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• August 1, 2024 | Ancient Mystery Deepens With Discovery of Denisovan Remains in Tibetan Cave
• August 1, 2024 | Boost Your Workout: Scientists Have Discovered a New Treatment for Fatigue Caused by Exercise
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Chemistry August 1, 2024

Decoding Earth’s Ancient Atmosphere: Life’s Role in Shaping Our World

A recent scientific study traces the co-evolution of Earth’s atmosphere, oceans, and life over 500 million years, revealing how organisms like algae have modified and…

Speeding Up RNA Chip Synthesis With Revolutionary Technology

New Study Unfolds the Electric Mystery of Peptides

125 Years After Its Discovery, Actinium’s Chemistry Still Baffles Scientists

Microscopic Building Blocks: New Dual-Functional Supramolecular Structures Unveiled

Scientists Develop Extraordinary Material That Can Transform Sunlight and Water Into Clean Energy

Leveraging “Atomic Intelligence” – Researchers Propose Innovative New Method To Drastically Reduce Industrial Emissions

Revolutionizing THC Testing: Detecting Cannabis With Just a Few Drops of Saliva

100% Breakdown: Revolutionary New Method Uses Light To Clean Up Forever Chemicals

Chemistry July 26, 2024

Unique Pigments Discovered: Chemists Unveil New Secrets of Rembrandt’s Famous Painting “The Night Watch”

Researchers have discovered that Rembrandt used special arsenic sulfide pigments to create a ‘golden’ paint in “The Night Watch.” Chemists at the Rijksmuseum and the…

Chemistry July 25, 2024

DOE Researchers Discover New Cheaper, and More Efficient Way To Produce Important Chemical

Combining zirconium with silicon nitride improves the transformation of propane, a component of natural gas, into polypropylene, a highly sought-after plastic. Polypropylene is a widely…

Chemistry July 24, 2024

Magnetic Butterfly: Scientists Unveil Groundbreaking Design Concept for Next-Generation Quantum Materials

NUS researchers have created a new butterfly-shaped magnetic nanographene that could improve quantum computing by enabling better control of electron spins and extending the coherence…

Chemistry July 22, 2024

Chemists Use Electricity To Turn Waste Molecules Into Valuable Liquid Fuel

A study has revealed a more efficient method for creating methanol. For years, chemists have been striving to synthesize valuable materials from waste molecules. Now,…

Chemistry July 21, 2024

Electroadhesion: The Magic of Making Materials Stick Without Glue [Video]

A novel electroadhesion process allows for the easy and reversible attachment of hydrogels to metals using electricity, effective on a variety of materials from food…

Chemistry July 20, 2024

“This Had Never Been Done Before” – New Dual-Use Catalyst Overcomes the Thermodynamic Canyon

German researchers have created a catalyst that converts ammonia into hydrogen and nitrite, potentially combining hydrogen production and fertilizer creation in one process. A research…

Chemistry July 19, 2024

Scientists Transform Molecules Into Mondrian Masterpieces

Trinity College researchers developed a computer program that visualizes molecular structures in Piet Mondrian’s artistic style, enhancing understanding of molecular symmetry and offering a novel…

Chemistry July 17, 2024

Breaking the Efficiency Bottleneck: The Power of Doping in Photocatalytic Water Splitting

Photocatalytic water splitting, employing strategies like doping and defect control, has seen efficiency improvements, notably through recent advancements in doping methods that optimize energy conversion…

Chemistry July 16, 2024

Revolutionizing H2O2 Production: Ultrathin Nanosheets Show Immense Promise

Recent research has demonstrated the effectiveness of ultrathin Bi4O5Br2 nanosheets with controlled oxygen vacancies in enhancing the piezocatalytic production of hydrogen peroxide (H2O2), presenting a…

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• ACS Publications

10 Hot Topics in Chemistry so far in 2022

• Jul 8, 2022

In any field, there are always some current topics that get pulses racing. Chemistry is no different, so today we bring you our top ten hot topics of the summer. Grab an iced drink, and see if you agree with our run down…

AI and Big Data

At number ten, it’s artificial intelligence and big data in water environments. These powerful new tools are increasingly being used in environmental science to assess risks, examine contaminants, identify and characterize pollution sources, and to model water treatment processes. But there remain opportunities and challenges in applying machine learning and data analytics to solving environmental problems, and it is hoped that new techniques will significantly advance water-related research in the coming years. 1

10 Hot Topics in Chemistry So Far in 2023

Thermochemical processing of waste and biomass.

Next up: recent advances in biomass and wastes thermochemical processing. Earlier in the year the ACS journal Energy & Fuels highlighted developments presented by participants at a virtual symposium organized by the Washington State University Pacific Northwest National Laboratory Bioproducts Institute. The world is gradually transitioning from an era fueled by fossil power to one characterized by sustainability and renewable resources. Recent progresses the understanding of biomass thermochemical reactions are allowing research communities to visualize these in practical solutions to mitigate environmental issues. Contents within the issue fall into four areas: (1) fundamentals of biomass thermochemical reactions, (2) liquefaction technologies, (3) catalytic upgrading/refining, and (4) techno-economic analysis/material. 2

Next Gen Active Materials

At eight, bioconjugate biomaterials, and the next generation of active materials. Biomaterials are redefining modern medicine – from new chemical strategies to modify hydrogels, or biocompatible methods to stabilize proteins and peptides, biomaterials are changing the detection and treatment of disease. In addition, engineered systems reveal new insights into biological processes, including stem cell signaling, cellular motions, and tissue repair, with many applications in human health. 3

Advances in TB drug discovery and diagnosis

Or how about drug discovery and diagnosis in tuberculosis? Before the emergence of SARS-CoV-2, tuberculosis was the leading cause of death from an infectious disease, with drug resistance limiting the effectiveness of current treatments. But recent advances in drug discovery and diagnostics promise new efforts to combat this global health threat, which may come back to the forefront as COVID recedes. 4

Smoking and chemical toxicology

At six, research into the chemical toxicology of smoking – with consideration of the use of cigarettes, e-cigarettes, and cannabis, particularly given the rise of lung injury cases associated with vaping. It is likely that both conventional and innovative chemical tools will play a major role in understanding the mechanisms of toxicity of tobacco and its related products, as well as the transformation of e-cigarette constituents during vaping. 5

Process safety in chemistry

Into the top five now, and our pick is process safety. Many industrial chemical incidents happen around the world every year, resulting in deaths, property damage, and disrupted supply chains. Systematically studying process performance and learning from the past is an effective way to prevent such incidents, with new research contributing to strategies for improving chemical safety across natural, social, management, and engineering sciences. 6

Catalysis and energy snapshot in China

At four, energy and catalysis, with a focus on China. Energy plays a central role in society, and the hunt for clean and sustainable resources is becoming one of the most important global issues of our time. Over the past decade, researchers in China have made extensive efforts and achieved significant advances in the fields of energy and catalysis – both in the understanding of fundamental mechanisms, and the development of efficient materials and devices. 7

Applied chemistry in healthcare

The top three hot topics in this selection all take us back into chemical applications in healthcare. At three is antifungal drug discovery. Fungal diseases cause millions of deaths each year, and can increase the morbidity of other bacterial and viral infections. Current treatments such as polyenes, azoles, and echinocandins are old, and often do not offer cure – as well as being associated with severe side effects. New research and development is needed to improve outcomes, and to keep pace with emerging pathogens. 8

Neglected tropical diseases

Coming in at number two, neglected tropical diseases, which affect more than a billion people worldwide in tropical areas and impoverished communities. This category of diseases includes schistosomiasis, which can damage the bladder, kidneys and liver, and other tropical parasites. ACS journals collaborated in a special virtual issue to showcase recent advances in the diagnosis and treatment of these illnesses. 9

And our number one hot topic for the summer of 2022 – it’s vaccines. As we have all seen in recent years, vaccines are a key mitigation strategy against viruses. But their application is wider than just inoculating against infectious pathogens; indeed, they show utility in cancer and other diseases, and are driving new options for personalized medicine. Now, new materials and conjugation methods may simplify production and enhance outcomes. Furthermore, new biomolecules and display modalities can expand the reach of vaccines to target emerging and endemic viruses. Improved strategies to deliver vaccines and induce immunogenicity are critical to protect against future outbreaks. 10

All these topics have been covered in recent special and virtual issues of ACS journals. Visit the website to explore more, and connect with us on social media to tell us about your own favourite hot topics in the world of chemistry.

• AI and Big Data in Water Environments. ACS EST Water Available at: https://pubs.acs.org/page/aewcaa/vi/ai-big-data-water-environments .
• Recent Advances in Biomass and Wastes Thermochemical Processing. Energy Fuels Available at: https://pubs.acs.org/page/enfuem/vi/thermochemical-processing
• Bioconjugate Biomaterials: Leveraging Biology for the Next Generation of Active Materials. Bioconjugate Chem Available at: https://pubs.acs.org/page/bcches/vi/bioconjugatebiomaterials
• Tuberculosis Drug Discovery and Diagnosis. ACS Infect Dis Available at: https://pubs.acs.org/page/vi/tuberculosis
• Chemical Toxicology of Cigarette, e-Cigarette and Cannabis Smoking. Chem Res Toxicol Available at: https://pubs.acs.org/page/crtoec/vi/chemical-toxicology-cigarette
• Process Safety from Bench to Pilot to Plant. A special collaboration issue. Available at: https://pubs.acs.org/page/vi/process-safety-bench-pilot-plant
• Energy and Catalysis in China. J Phys Chem C Available at: https://pubs.acs.org/page/jpccck/vsi/energy-catalysis-china
• Antifungal Drug Discovery. A special collaboration issue. Available at: https://pubs.acs.org/page/vi/antifungals
• Neglected tropical Diseases. A special collaboration issue. Available at: https://pubs.acs.org/page/vi/ntdday
• Vaccine Strategies. Bioconjugate Chem Available at: https://pubs.acs.org/page/bcches/vi/vaccinestrategies

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Drugs and vaccines could be freed from cold chains by hydrogel

Stiff gel prevents proteins from aggregating, preserving their therapeutic power

Iron coatings help Komodo dragons maintain their sharp ziphodont teeth

Research sheds light on structure–function relationships in teeth of carnivorous reptiles

Electrocatalyst-in-a-box recycles nitrogen species to produce ammonia from wastewater

Electrochemical catalytic system can handle real wastewater

Amorphous clusters across a vast range of sizes found to affect crystal nucleation

The clusters provide sites for nucleation, which contradicts classical nucleation theory

Nanopore proteins designed from scratch and turned into biosensors

Designer ylide transfers single carbon atoms, optical trap experiments pick up recoil of a single alpha particle blasting off, computer program ‘paints’ porphyrin structures in the style of famous artist, forgotten borole synthesis expands family of antiaromatic compounds, imaging study illuminates new type of electrical tree.

Fast charging supercapacitors

Rapid development of the alternative energy storage technology to rechargeable batteries is already having real world impact. James Mitchell Crow talks to the scientists working on upping their performance

Is DNA the future of digital data storage?

DNA is being explored as a long-term solution to preserving digital information for future generations. Nina Notman reports

The wonder of whisky

Kit Chapman takes a closer look at the chemistry of the water of life, from the slow reactions of its ageing to testing for fakes

Brain chemistry basics

Andy Extance looks into the latest in Alzheimer’s disease, pain and memory

The proteins that drive drug addiction

Jamie Durrani speaks to researchers exploring how epigenetic changes in the brain affect drug-seeking behaviours

Algorithm predicts bitterness from mass spectra data alone

Plastic recycling studies need reliable polymer data. this database is ready to inform them, new gene-editing tool found in bacterium could carry out extensive genome remodelling, genetic engineering feat coaxes yeast to produce valuable vaccine compound.

Electrochemical reaction outcomes controlled by customised AC waveforms

Glycolysis method breaks down mixed textiles for recycling, a sneak peek at the atomic secrets of copper-catalysed electroreduction of carbon dioxide, ‘lasagna-like’ layered structure could triple productivity of water splitting.

PFAS from rechargeable batteries pose environmental threat

Zinc–air batteries created from paper industry waste, cold plasma converts biogas into long-chain hydrocarbon feedstocks, environmental, cassini probe’s radar provide new insight into titan’s liquid hydrocarbon seas.

Xylitol latest sugar alcohol to be linked to heart attacks and strokes

Microscopy structures reveal mechanism behind bitter taste, brewing better belgian beer with artificial intelligence.

First single crystal structure of actinium shows unexpected coordination behaviour

Ai trained on photos of salt ‘stains’ can predict their chemical composition, all-metal aromatic ring isolated for the first time, redox-fluid ligand stabilised as triradical for the first time.

Mechanochemistry adds fluorine to discarded polystyrene

Companion compound for naloxone could boost opioid reversal effects, save lives, conjugate vaccine curbs xylazine effects in mice, nanoscience.

Oxygen-free conditions are key to high-quality graphene

Oxygen’s exotic yet stable bonding in graphene explained, liquid metal synthesis of diamonds achieved at atmospheric pressure, study raises questions about media used for in vitro tests on nanomaterials.

Super-fast automated synthesis promises to make chemistry accessible to many more

Impossible aerogel that reflects more visible light than it receives prompts scepticism, water droplets accelerate formation of mineral nanoparticles essential for life, computational chemistry.

New tool could find use in food science and drug development 

Calculations and experiments reveal that water microdroplets may play role in soil formation

Labs across the globe networked by AI discover state-of-the-art emitters for lasers

Demonstration shows how algorithms could organise timing and match specialist equipment to experiments

AI predicts vape flavours can break down into potentially harmful compounds when heated

Algorithm designs proteins from scratch that can bind drugs and small molecules, simulations track how mofs adsorb water, one molecule at a time, culture and people.

2024-07-23T13:30:00+01:00 By Zahra Khan

Algorithm turns molecules’ structure into Mondrian-inspired representations

Pioneering preservative removal from ancient Greek ship allows accurate dating

Lead found in Beethoven’s hair reveals new insight into his ailing health

Chemical analysis reveals origins of early English silver coins

Using analytical chemistry to illuminate the unlisted ingredients in tattoo inks

Striking reptilian fossil discovered in 1931 found to be fake.

280-million-year-old lizard ‘fossil’ was mostly painted on

Chemistry tools reveal surprise lead layer under a Rembrandt masterpiece

X-ray imaging uncovers a surprising lead substance beneath  The Night Watch , likely used to safeguard the famous painting from moisture

Playing her part in building South Africa’s scientific reputation

Meet Pinkie Ntola, an early-career Black researcher who is passionate about being a credible scientist, an inspiring teacher and a supportive mentor

Green chemistry

Science needs to get its house in order when it comes to energy use and waste

Labs have an outsized environmental footprint but solutions are within reach 

Redox reactions ‘mine’ old fluorescent light bulbs for europium

In just three simple steps rare earth element can be recovered, avoiding ‘ecologically devastating’ mining

Biomass, plastic waste and carbon dioxide feedstocks key to cutting chemical industry’s emissions

Royal Society report warns that without intervention defossilisation of the chemicals sector will take many decades

Analysis of three French chemistry labs shows how they could halve their carbon footprint by 2030

Open-source tool helps researchers evaluate a series of carbon mitigation strategies

There’s a world of chemistry in water

Managing our most precious resource

Riding the microwave: three chemists share their stories

Disagreements surrounding non-thermal effects didn’t stop microwave reactors becoming a standard part of laboratory life

Public support high for recruiting best students and talent for UK universities

Immigration remains a polarising topic for the country though, even where universities are concerned

Caltech gets new theoretical chemistry centre that honours Nobel laureate

Two former chemistry postdocs pledge $30 million to build the Rudy Marcus Center

How hoarding knowledge is hurting the industry in the long run

Sharing results that are not commercially viable would speed up research

Elemental analysis under scrutiny again as competition raises accuracy questions

Doubts grow over the standard used by journals as competition highlights 26% failure rate with simple molecule

Japanese chemistry institute sues archival site for hosting discontinued journal

Case could set an important precedent if it reaches court

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100+ Great Chemistry Research Topics

Table of contents

• 1 5 Tips for Writing Chemistry Research Papers
• 2 Chemical Engineering Research Topics
• 3 Organic Сhemistry Research Topics
• 4 Іnorganic Сhemistry Research Topics
• 5 Biomolecular Сhemistry Research Topics
• 6 Analytical Chemistry Research Topics
• 7 Computational Chemistry Research Topics
• 8 Physical Chemistry Research Topics
• 9 Innovative Chemistry Research Topics
• 10 Environmental Chemistry Research Topics
• 11 Green Chemistry Research Topics
• 12.1 Conclusion

Do you need a topic for your chemistry research paper? Are you unsure of where to start? Don’t worry – we’re here to help. In this post, we’ll go over a series of the best chemistry research paper topics as well as Tips for Writing Chemistry Research Papers on different topics. By the time you finish reading this post, you’ll have plenty of ideas to get started on your next research project!

There are many different subfields of chemistry, so it can be tough to find interesting chemistry topics to write about. If you’re struggling to narrow down your topic, we’ll go over lists of topics in multiple fields of study.

Doing research is important to help scientists learn more about the world around us. By researching different compounds and elements, we can learn more about how they interact with one another and how they can be used to create new products or improve existing ones.

There are many different topics that you can choose to research in chemistry. Here are just a few examples:

• The history of chemistry and how it has evolved over time
• How different chemicals react with one another
• How to create new compounds or improve existing ones
• The role of chemistry in the environment
• The health effects of different chemicals

5 Tips for Writing Chemistry Research Papers

Once you have chosen a topic for your research paper , it is important to follow some tips to ensure that your paper is well-written and accurate. Here are a few tips to get you started:

• Start by doing some background research on your topic. This will help you understand the basics of the topic and give you a good foundation to build your paper on.
• Make sure to cite all of the sources that you use in your paper. This will help to show where you got your information and will also help to add credibility to your work.
• Be sure to proofread your paper before you submit it. This will ensure that there are no errors and that your paper is clear and concise.
• Get help from a tutor or friend if you are struggling with your paper. They may be able to offer helpful advice or feedback.
• Take your time when writing your research paper . This is not a race, and it is important to make sure that you do a good job on your research.

By following these tips, you can be sure that your chemistry research paper will be a success! So what are you waiting for? Let’s go over some of the best research paper topics out there.

Chemical Engineering Research Topics

Chemical Engineering is a branch of engineering that deals with the design and application of chemical processes. If you’re wondering how to choose a paper topic, here are some ideas to inspire you:

• How to create new alloy compounds or improve existing ones
• The health effects of the food industry chemicals
• Chemical engineering and sustainable development
• The future of chemical engineering
• Chemical engineering and the food industry
• Chemical engineering and the pharmaceutical industry
• Chemical engineering and the cosmetics industry
• Chemical engineering and the petrochemical industry
• Biocompatible materials for drug delivery systems
• Membrane technology in water treatment
• Development of synthetic fibers for industrial use

These are just a few examples – there are many more possibilities out there! So get started on your research today. Who knows what you might discover!

Need expert assistance with a research project? Get your paper written by a professional writer Get Help Reviews.io 4.9/5

Organic Сhemistry Research Topics

Organic chemistry is the study of carbon-containing molecules. There are many different organic chemistry research topics that a student could choose to focus on and here are just a few examples of possible research projects in organic chemistry:

• Investigating new methods for synthesizing chiral molecules
• Studying the structure and reactivity of carbon nanotubes
• Investigating metal complexes with organometallic ligands
• Designing benzene derivatives with improved thermal stability
• Exploring new ways to control the stereochemistry of chemical reactions
• Studying the role of enzymes in organic synthesis
• Investigating new strategies for combating drug resistance
• Developing new methods for detecting explosives residues
• Studying the photochemistry of organic molecules
• Studying the behavior of organometallic compounds in biological systems
• Synthetic routes for biodegradable plastics
• Catalysis in organic synthesis
• Development of non-toxic solvents

Іnorganic Сhemistry Research Topics

Inorganic Chemistry is the study of the chemistry of materials that do not contain carbon. Unlike other chemistry research topics, these include elements such as metals, minerals, and inorganic compounds. If you are looking for inorganic chemistry research topics on inorganic chemistry, here are some ideas to get you started:

• How different metals react with one another
• How to create new alloys or improve existing ones
• The role of inorganic chemistry in the environment
• Rare earth elements and their applications in electronics
• Inorganic polymers in construction materials
• Photoluminescent materials for energy conversion
• Inorganic chemistry and sustainable development
• The future of inorganic chemistry
• Inorganic chemistry and the food industry
• Inorganic chemistry and the pharmaceutical industry
• Atomic structure progressive scale grading
• Inorganiс Сhemistry and the cosmetics industry

Biomolecular Сhemistry Research Topics

Biomolecular chemistry is the study of molecules that are important for life. These molecules can be found in all living things, from tiny bacteria to the largest animals. Researchers who work in this field use a variety of techniques to learn more about how these molecules function and how they interact with each other.

If you are looking for essential biomolecular chemistry research topics, here are some ideas to get you started:

• The structure and function of DNA
• Lipidomics and its applications in disease diagnostics
• The structure and function of proteins
• The role of carbohydrates in the body
• The role of lipids in the body
• How enzymes work
• Protein engineering for therapeutic applications
• The role of biochemistry in heart disease
• Cyanides and their effect on the body
• The role of biochemistry in cancer treatment
• The role of biochemistry in Parkison’s disease treatment
• The role of biochemistry in the immune system
• Carbohydrate-based vaccines

The possibilities are endless for someone willing to dedicate some time to research.

Analytical Chemistry Research Topics

Analytical Chemistry is a type of chemistry that helps scientists figure out what something is made of. This can be done through a variety of methods, such as spectroscopy or chromatography. If you are looking for research topics, here are some ideas to get you started:

• How food chemicals react with one another
• Mass spectrometry
• Microplastics detection in marine environments
• Development of sensors for heavy metal detection in water
• Analytical aspects of gas and liquid chromatography
• Analytical chemistry and sustainable development
• Atomic absorption spectroscopy methods and best practices
• Analytical chemistry and the pharmaceutical industry in Ibuprofen consumption
• Analytical chemistry and the cosmetics industry in UV protectors
• High-throughput screening methods in pharmaceutical analysis
• Dispersive X-ray analysis of damaged tissues

Analytical chemistry is considered by many a complex science and there is a lot yet to be discovered in the field.

Computational Chemistry Research Topics

Computational chemistry is a way to use computers to help chemists understand chemical reactions. This can be done by simulating reactions or by designing new molecules. If you are looking for essential chemistry research topics in computational chemistry, here are some ideas to get you started:

• Molecular mechanics simulation
• Machine learning applications in predicting molecular properties
• Reaction rates of complex chemical reactions
• Designing new molecules: how can simulation help
• The role of computers in the study of quantum mechanics
• How to use computers to predict chemical reactions
• Using computers to understand organic chemistry
• The future of computational Chemistry in organic reactions
• The impacts of simulation on the development of new medications
• Combustion reaction simulation impact on engine development
• Quantum-chemistry simulation review
• Simulation of protein folding and misfolding in diseases
• Development of algorithms for chemical synthesis planning
• Applications of Metal-Organic Frameworks in water sequestration and catalysis

Computers are cutting-edge technology in chemical research and this relatively new field of study has a ton yet to be explored.

Physical Chemistry Research Topics

Physical chemistry is the study of how matter behaves. It looks at the physical and chemical properties of atoms and molecules and how they interact with each other. If you are looking for physical chemistry research topics, here are some ideas to get you started:

• Standardization of pH scales
• Structure of atom on a quantum scale
• Bonding across atoms and molecules
• The effect of temperature on chemical reactions
• The role of light in in-body chemical reactions
• Chemical kinetics
• Molecular dynamics in confined spaces
• Quantum computing for solving chemical problems
• Studies on non-Newtonian fluids in industrial processes
• Surface tension and its effects on mixtures
• The role of pressure in chemical reactions
• Rates of diffusion in gases and liquids
• The role of entropy in chemical reactions

Here are just a few samples, but there are plenty more options! Start your research right now!

Innovative Chemistry Research Topics

Innovative chemistry is all about coming up with new ideas and ways to do things. This can be anything from creating new materials to finding new ways to make existing products. If you are looking for ground-breaking chemistry research topics, here are some ideas to get you started:

• Amino acids side chain effects in protein folding
• Chemistry in the production of nanomaterials
• The role of enzymes in chemical reactions
• Photocatalysis in 3D printing
• Avoiding pesticides in agriculture
• Combining chemical and biological processes
• Gene modification in medicinal chemistry
• The role of quantum mechanics in chemical reactions
• Astrochemical research on extraterrestrial molecules
• Spectroscopy signatures of pressurized organic components
• Development of smart materials with responsive properties
• Chemistry in space: studying chemical reactions in microgravity
• Utilization of CO2 in chemical synthesis
• Use of black soldier fly carcasses for bioplastic production using extracted chitin
• Bioorthogonal chemistry for molecule synthesis inside living systems

If you need a hand, there are several sites that also offer research papers for sale and can be a great asset as you work to create your own research papers.

Whatever route you decide to take, good luck! And remember – the sky’s the limit when it comes to research! So get started today and see where your studies may take you. Who knows, you might just make a breakthrough discovery!

Environmental Chemistry Research Topics

Environmental Chemistry is the study of how chemicals interact with the environment. This can include anything from the air we breathe to the water we drink. If you are looking for environmental chemistry research topics, here are some ideas to get you started:

• Plastic effects on ocean life
• Urban ecology
• The role of carbon in climate change
• Air pollution and its effects
• Water pollution and its effects
• Chemicals in food and their effect on the body
• The effect of chemicals on plant life
• Earth temperature prediction models
• Effects of pharmaceuticals in aquatic environments
• Atmospheric chemistry and urban air quality
• Bioremediation techniques for oil spill cleanup
• Regulatory and environmental impact of Per- and Polyfluoroalkyl (PFA) substances
• Comparison of chemical regulation impacts like PFA with historical cases such as lead in fuel

A lot of research on the environment is being conducted at the moment because the environment is in danger. There are a lot of environmental problems that need to be solved, and research is the key to solving them.

Green Chemistry Research Topics

Green chemistry is the study of how to make products and processes that are environmentally friendly. This can include anything from finding new ways to recycle materials to developing new products that are biodegradable. If you are looking for green chemistry research topics, here are some ideas to get you started:

• Recycling and reuse of materials
• Developing biodegradable materials
• Improving existing recycling processes
• Green chemistry and sustainable development
• The future of green chemistry
• Green chemistry and the food industry
• Lifecycle assessment of chemical processes
• Green chemistry and the pharmaceutical industry
• Development of catalysts for green chemistry
• Green chemistry and the cosmetics industry
• Alternative energy sources for chemical synthesis

A more environmentally friendly world is something we all aspire for and a lot of research has been conducted on how we can achieve this, making this one of the most promising areas of study. The results have been varied, but there are a few key things we can do to make a difference.

Controversial Chemistry Research Topics

Controversial chemistry is all about hot-button topics that people are passionate about. This can include anything from the use of chemicals in warfare to the health effects of different chemicals. If you are looking for controversial topics to write about , here are some ideas to get you started:

• The use of chemicals in warfare
• Gene modification in human babies
• Bioengineering
• How fast food chemicals affect the human brain
• The role of the government in regulating chemicals
• Evolution of cigarette chemicals over time
• Chemical effects of CBD oils
• Ethical issues in genetic modification of organisms
• Nuclear energy: risks and benefits
• Use of chemicals in electronic waste recycling
• Antidepressant chemical reactions
• Synthetic molecule replication methods
• Gene analysis

Controversial research papers often appear in the media before it has been peer-reviewed and published in a scientific journal. The reason for this is that the media is interested in stories that are new, exciting, and generate a lot of debate.

Chemistry is an incredibly diverse and interesting field, with many controversial topics to write about. If you are looking for a research topic, consider the examples listed in this article. With a little bit of effort, you are sure to find a topic that is both interesting and within your skillset.

In order to be a good researcher, it is important to be able to think critically and solve problems. However, innovation in chemistry research can be challenging. When thinking about how to innovate, it is important to consider both the practical and theoretical aspects of your research. Additionally, try to build on the work of others in order to create something new and unique. With a little bit of effort, you are sure to be able to find a topic that is both interesting and within your skillset.

Happy writing!

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• Brief Communication
• Open access
• Published: 22 July 2024

Evidence of dark oxygen production at the abyssal seafloor

• Andrew K. Sweetman   ORCID: orcid.org/0000-0002-9547-9493 1 ,
• Alycia J. Smith 2 ,
• Danielle S. W. de Jonge   ORCID: orcid.org/0000-0002-4093-2721 1 ,
• Tobias Hahn   ORCID: orcid.org/0000-0002-9001-5753 3 ,
• Peter Schroedl   ORCID: orcid.org/0000-0002-9874-3800 4 ,
• Michael Silverstein   ORCID: orcid.org/0000-0003-2205-3624 5 ,
• Claire Andrade 4 ,
• R. Lawrence Edwards 6 ,
• Alastair J. M. Lough   ORCID: orcid.org/0000-0002-8095-9064 7 ,
• Clare Woulds 7 ,
• William B. Homoky   ORCID: orcid.org/0000-0002-9562-8591 7 ,
• Andrea Koschinsky   ORCID: orcid.org/0000-0002-9224-0663 8 ,
• Sebastian Fuchs 9 ,
• Thomas Kuhn 9 ,
• Franz Geiger 10 &
• Jeffrey J. Marlow   ORCID: orcid.org/0000-0003-2858-8806 4  

Nature Geoscience ( 2024 ) Cite this article

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• Element cycles
• Environmental chemistry
• Environmental impact
• Marine biology
• Marine chemistry

Deep-seafloor organisms consume oxygen, which can be measured by in situ benthic chamber experiments. Here we report such experiments at the polymetallic nodule-covered abyssal seafloor in the Pacific Ocean in which oxygen increased over two days to more than three times the background concentration, which from ex situ incubations we attribute to the polymetallic nodules. Given high voltage potentials (up to 0.95 V) on nodule surfaces, we hypothesize that seawater electrolysis may contribute to this dark oxygen production.

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Oxygen (O 2 ) is prevalent in deep-sea surface sediments where its rate of consumption reflects the sum of aerobic respiration and oxidation of reduced inorganic compounds produced by anaerobic decay. These processes define sediment community O 2 consumption (SCOC), and quantifying SCOC is needed to estimate fluxes of major elemental cycles through marine systems 1 , 2 , 3 . We undertook multiple in situ benthic chamber lander experiments to measure abyssal SCOC in the Nauru Ocean Resources Inc. (NORI)-D licence area of the Clarion–Clipperton Zone (CCZ; Extended Data Fig. 1 and Extended Data Table 1 ) where polymetallic nodules cover extensive areas of seafloor. Sediments and nodules were exposed to different experimental treatments, which included the addition of dead-algal biomass, dissolved inorganic carbon and ammonium (NH 4 + ) or cold filtered surface seawater. No-injection controls were also performed. In contrast to previous deep-sea O 2 flux studies that only showed SCOC, we consistently found that more O 2 was accumulating in the chambers than was being consumed, resulting in net O 2 production.

Constant linear decreases in O 2 optode readings were observed in two experiments (Fig. 1 ), and SCOC determined by in situ O 2 microprofiling was 0.7 mmol O 2  m −2  d −1 indicating that SCOC occurs in NORI-D as in many abyssal habitats 2 , 3 , 4 . However, O 2 concentrations in 25 benthic chamber incubations started at 185.2 ± 2.9 µmol l −1 (1 standard error (SE)) and reached O 2 maxima between 201 and 819 µmol l −1 over 47 h (Fig. 1 ), indicating net dark O 2 production (DOP) corresponding to rates of 1.7–18 mmol O 2  m −2  d −1 . Independent measurements of O 2 concentration using the Winkler method also showed DOP (Extended Data Fig. 2 ), providing evidence that the optodes were not malfunctioning. No statistically significant difference in the total net O 2 produced (maximum [O 2 ] – initial [O 2 ]; Extended Data Table 2 ) was found between chambers (ANOVA, F 2,9  = 0.107, p  = 0.900) or experimental treatments (ANOVA, F 3,9  = 0.876, p  = 0.489), ruling out any experimental bias. We found no difference in the total net O 2 produced between cruises (ANOVA, F 2,12  = 0.391, p  = 0.684), though DOP was correlated to the average surface area of the nodules (Spearman’s correlation, ⍴  = 0.664, p  = 0.031). A re-evaluation of in situ O 2 optode data collected from 36-h benthic chamber experiments in the abyssal eastern and western CCZ (Extended Data Figs. 1 and 3 ) also showed DOP, indicating its occurrence in multiple locations across the CCZ. Our findings contrast with all published deep-sea benthic O 2 flux studies and suggest that DOP may provide O 2 for benthic respiration. Whereas the DOP measured was greater than SCOC, we would urge caution when temporally upscaling our results, as the nonlinear production of O 2 suggests that DOP may not be continuous in nature. Moreover, the variance in DOP activity seen between experiments and its relationship to nodule surface area suggests DOP activity may change with nodule spatial density and type (for example, diagenetic versus hydrogenetic), so upscaling our results by area is also imprudent without additional studies.

a – c , The in situ benthic chamber lander deployments were made during the 5D ( a ), 5E ( b ) and 7A ( c ) cruises to the NORI-D license area (Extended Data Fig. 1 ). Nodules were present in all incubation experiments. The green hue, blue hue and red lines in the 5D figure ( a ) denote dead-algal biomass, dissolved inorganic carbon + NH 4 + and filtered seawater treatments, respectively. The gap in the optode data in AKS279-Ch.3 was caused by the optode periodically not logging data. The black line indicates ambient O 2 concentration measured on the outside of the benthic chambers during AKS273 on the 5D cruise. The green and yellow hue lines in the 5E ( b ) and 7A ( c ) figures denote the dead-algal biomass and control (no injection) treatments, respectively. The minor drops seen in some of the O 2 concentration profiles at 28, 38 and 47 h are caused by the dilution of the chamber water with 50 ml of seawater that was entrained from the outside into the chamber through a 1.5 m (0.25 cm diameter) open tube when the syringe sampler collected seawater samples from within the chamber. The constant O 2 concentration measured during the first 2 h of the 5D and 7A experiments was due to the stirrers being turned off for 1 h to allow the substrates (for example, dead-algal biomass) to sink to the sediment surface. Stirrers were turned on during the 5E expedition from the moment the lander was deployed until the lander returned and power to the stirrers was disconnected.

Source data

Several lines of evidence indicate that the DOP was not caused by experimental artefacts. First, the total O 2 change between the experimental and control (non-injection) treatments was statistically indistinguishable, and a steady increase in O 2 concentration was recorded over many hours in multiple experiments; these observations demonstrate that DOP was not attributable to the injection of exogenous fluids. Second, diffusion of O 2 from trapped air bubbles within the chamber was unlikely because each chamber uses two one-way valves in the lid to purge air from the chambers as the lander sinks. Even if an air bubble could be trapped long enough to reach the seafloor, gaseous diffusion of O 2 into the water phase would take < 1 s at 4,000 m depth (Extended Data Table 3 ), which is inconsistent with the steady increase in O 2 over many hours seen in multiple experiments (Fig. 1 ). Third, intrusion of O 2 from the plastic chambers into the water phase is unlikely ( Methods ) as they are built from polyoxymethylene, which is both highly inert and chemically stable in well-oxygenated settings and would not explain the variation in DOP because all experiments used identical materials. Last, DOP was also observed during 48-h ex situ sediment incubations (Extended Data Fig. 4 ).

Several lines of enquiry were pursued to explain the DOP. Subsurface advection of oxic bottom water from seamount flanks into seafloor sediments 5 , 6 and then into the chambers was discounted based on in situ O 2 microprofiling that showed pore water was a net sink for O 2 and undersaturated compared with the O 2 seen in the chambers. Furthermore, DOP was measured in sealed ex situ experiments (Extended Data Fig. 4 ) that prevented O 2 intrusion from below. It is unlikely that biological mechanisms were responsible for the bulk of the DOP as ex situ core incubations revealed DOP in the presence of poison (HgCl 2 ; Extended Data Fig. 4 ). Whereas many microbes in the CCZ are able to detoxify Hg (II) to Hg (0) 7 , and some microhabitat pore spaces in the core may have remained HgCl 2 free, the taxa known to be capable of DOP (for example, Nitrosopumilus maritimus ) are killed by its addition 8 . We also observed weak statistical support between the relative abundance of certain nitrogen-cycling microbial taxa and DOP (for example, Candidatus Nitrosopumilus ⍴  = 0.474, p  = 0.420). The fact that DOP was detected in ex situ controls containing only polymetallic nodules (Extended Data Fig. 4 ) suggested that the DOP was linked to their presence. Hence, we estimated the potential contribution of radiolytic O 2 production using a kinetic model 9 and found 0.18 μmol l −1  O 2 would be generated by this process within 48 h. We also modelled the chemical reduction of manganese (IV) oxide at in situ temperature (1.6 °C) across a range of pH and O 2 conditions encountered at the seafloor to assess if this reaction (2MnO 2  → 2MnO + O 2 ;Extended Data Fig. 5 ) could liberate the O 2 but found that <0.1 nmol of manganese (IV) oxide would be chemically reduced to manganese (II) at seafloor conditions. As such, localized radiolytic O 2 production from the sediments and nodules and chemical dissolution explain only a negligible proportion (< 0.5%) of the DOP observed.

The oxygen evolution reaction requires an input voltage of 1.23 V plus an overpotential of approximately 0.37 V to split seawater into H 2 and O 2 (ref. 10 ) at NORI-D’s seafloor mean pH (7.41). This value can be lowered by several hundred millivolts if the reaction proceeds via the lattice-oxygen-mediated mechanism 11 . Use of metal catalysts such as Mn oxides enriched with transition metals (for example, Ni) found in nodules 12 and characterized by large tunnel areas and abundant defect sites can optimize the adsorption of reactants and enhance conductivity and catalytic performance 11 , 13 , 14 . We tested the electrical potential between two platinum electrodes at 153 sites on the surfaces of 12 nodules (Fig. 2 ) from the UK1, NORI-D and Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) license areas. Although the potentials between different positions on the nodules were highly variable, - potentials up to 0.95 V were found and high mean background-corrected potentials were detected under cold-water conditions (Fig. 2 and Extended Data Table 4 ). On the basis of these studies and DOP being observed in nodule-only ex situ incubations (Extended Data Fig. 4 ), we hypothesize that the DOP may have partly resulted from seawater electrolysis, with the necessary energy coming from the potential difference between metal ions within the nodule layers, leading to an internal redistribution of electrons. Whereas questions remain concerning this potential mechanism (such as the identity of the energy source(s), longevity of DOP, catalytic stabilities, electrochemical conditions on exposed versus buried nodules surfaces and the influence of different chemistries within the nodule layers), the ‘geo-battery’ hypothesis was supported by the link between DOP and nodule average surface area. This connection could be due to an increased abundance of anode and cathode sites or a greater abundance of high Ni and Cu dendritic porous layers in larger nodules 15 . Assuming the ‘geo-battery’ is partly responsible for the DOP observed, the initial high DOP rate may have been related to the ‘bow-wave’ of the lander removing sediments from the surface of the nodules and exposing electrochemically active sites on the nodules. The slowdown in DOP seen later in the incubations could have then been caused by a reduction in voltage potential and/or degradation of metal-oxide catalysts that has been observed in Mn oxide catalysts previously 10 . Whereas this process requires further investigation, if true, DOP activity may fluctuate with sediment coverage on the nodules inviting the urgent question of how sediment remobilization and distribution over large areas during deep-sea mining may influence DOP.

The nodules were collected from the NORI-D (1-5), UK1 (6-8) and the BGR (9-12) license areas. Potentials were measured at 21 °C (nodules 1–12) and 5 °C (nodules 6 and 7 cold) and between two different UK1 nodules (Tests 1 and 2) and across the surface of a metamorphosed carbonate rock (control). Means are designated by the ‘x’ symbol, medians by the line, boxes show the lower and upper quartile values (excluding the median), whereas the whisker bars refer to the minimum and maximum data values. The number of technical replicate measurements made at different points on the surface of each nodule/rock to make each box-whisker is shown by the number above each whisker bar.

Understanding the mechanism(s) behind DOP, its temporal nature and its spatial distribution will allow its role in abyssal ocean ecosystems to be better understood. Future studies of DOP in the deep sea may also shed light on broader relationships between metal-oxide deposition, biological evolution and the oxygenation of Earth 16 , 17 .

A benthic chamber lander was deployed in the NORI-D license area six times in May–June 2021 (5D cruise), five times in November–December 2021 (5E cruise) and five times in August–September 2022 (7A cruise) (Extended Data Fig. 1 and Extended Data Table 1 ). The lander comprised three independent, autonomous, square benthic chambers (484 cm 2 ) separated by approximately <0.5 m. After arriving at the seafloor, the lander waited for 0.07–1.34 d before the chambers were pushed into the sediment to create an enclosed microcosm of the seafloor. Ten minutes into the incubation period, the enclosed chambers were injected with 50 ml of one of three solutions: (1) 0.45-µm-filtered, cold surface seawater containing 79.2 mg of freeze-dried Phaeodactylum tricornutum algae, (2) 32 µM Na 2 HCO 3 and 40 µM NH 4 Cl dissolved in cold artificial seawater (salinity 35) and (3) 0.45-µm-filtered, cold surface seawater. On some occasions, the injection mechanism failed allowing the response to control (no injection) conditions to be measured. The seafloor in the study area had a temperature of 1.6 °C ± 0.006 °C (SE, n  = 28) and a pH of 7.41 ± 0.05 (SE, n  = 17). Immediately after the injection, the overlying water was mixed with a submersible stirrer at 60 rpm for 1 min before the stirrer was turned off that allowed any particulate substrates to settle for 1 h. After 1 h, the stirrer was then turned on again for the remainder of the experiments. During the 5E expedition, the stirrers were programmed to continually stir the overlying water even immediately after injection.

The syringe samplers removed approximately 50 ml of seawater from the water phase of each chamber at 0.1 or 0.03, 1, 3, 9, 28, 38 and 47 h into the incubation experiment. Oxygen optodes (CONTROS HydroFlash O 2 manufactured by Kongsberg Maritime Contros GmbH) mounted in the lid of each chamber logged O 2 concentrations in the chamber every 10 seconds throughout each experiment. Two days before the first lander deployment of each cruise, the optodes underwent a two-point, multi-temperature calibration using 0 and 100% O 2 calibration solutions at 1.2, 7, 18 and 30 °C following the recommendations of Bittig et al. (ref. 18 ). On the 5D cruise, we also calibrated the sensors 2 d after the last lander experiment so we could estimate optode drift, which was negligible (0.27 µmol l −1  d − 1 ) over the course of the six-week cruise. The 0% and 100% O 2 saturation solutions were created by bubbling 0.45-µm-filtered surface seawater in a bottle sitting in a water-chilling/heating unit with N 2 gas (0%) or an aquarium air bubbling unit (100%) for 30 min. The O 2 concentration of the calibration solutions was confirmed in triplicate by Winkler titration. After incubating seafloor sediments for 47 h, the lander chambers were closed by a shutter door at the base of the chambers, and the chambers were then pulled slowly out of the sediment, which took 1 h. The lander was then recalled from the seafloor. In eight instances, the lander programme did not finish and the doors did not shut, preventing the sampling of sediment and determination of the volume of the water phase in the chambers (Extended Data Table 2 ). Once the lander was back and secured on deck, the chambers were opened and the water above the sediment removed via syphoning into a bucket. The distance from the top of the sediment to the base of the chamber lid was then measured in four places to get an accurate water depth for water volume estimates. Whenever possible, a photograph was then taken of the chamber sediment and nodules from directly above the opening of the chamber. All syringes containing water samples were removed and taken to the shipboard lab for immediate processing or stored in a cold lab (4 °C) before processing. The optodes were removed and their onboard data downloaded to a computer. Finally, the nodules were removed from the chambers and washed of attached organic debris with cold (4 °C), 0.45-µm-filtered surface seawater and placed in sterile Whirlpak bags to be weighed in the laboratory later. The number of polymetallic nodules at the seafloor determined from chamber counts was 1170 ± 97 m −2 .

Unfiltered syringe sample seawater was carefully transferred from each 50 ml syringe to a 12 ml exetainer via a 10 cm tube attached to the syringe nozzle, ensuring no air bubbles were introduced and immediately fixed for microWinkler titration. The sample was then mixed thoroughly using a glass bead placed in the exetainer and placed in the dark in a 4 °C refrigerator for 30–45 min to allow the precipitate to settle. Once the precipitate had sedimented, the exetainers were shaken again and left for 2–3 h before Winkler titrations were performed. All titrations were completed within 12 h after sampling to determine dissolved O 2 concentrations. Each Winkler sample (approximately 5 ml) was titrated twice, and duplicate measurements showed minor differences in O 2 concentration (5D cruise error: 3.5 ± 0.3 μmol l −1 , n  = 71; 5E cruise error: 1.3 ± 0.2 μmol l − 1 , n  = 69; 7A cruise error: 2.8 ± 0.4 μmol l − 1 , n  = 84). Winkler O 2 concentration data were averaged for each syringe sample. The O 2 concentrations estimated by Winkler analysis were 22 ± 1% ( n  = 42, SE, 5D cruise), 8 ± 4% ( n  = 39, SE, 5E cruise) and 24 ± 2% ( n  = 40, SE, 7A cruise) lower than the concentrations measured by the optodes at the same time point in the same incubations most likely due to out gassing of supersaturated O 2 caused by depressurization and warming of the externally mounted syringes (whose samples were used for Winkler analyses) during the lander recovery to the surface.

Back on shore, the final O 2 concentration values were calculated following Bittig et al. (ref. 18 ) from the optode, calibration and in situ pressure data that was derived from the depth where each lander deployment was made. Time stamps in the optode data were compared to the lander computer programme times so the optode readings could be aligned to the schedule of the chamber experiment. The total change in O 2 concentration in each chamber was then calculated from the volume of the water phase above the sediment and the difference in O 2 concentration from when the chambers started to seal off the sediment to the point when the maximum O 2 concentration was reached.

Benthic O 2 microprofiling

Benthic O 2 microprofiles were made during lander deployments AKS313, AKS316, AKS318 and AKS321 during the 5E cruise using a UNISENSE deep-sea microprofiling unit mounted <0.5 m from the benthic chambers. The microprofiles were made using 20 cm O 2 microsensors that penetrated the sediment in 0.05 mm steps. The microsensors were calibrated 2 h before the lander deployments at in situ temperature (1.6 °C) at 0% and 100% O 2 saturation (above). At each sampling depth, the microsensor stopped for 5 s before each measurement was made. The sensor then recorded five individual O 2 concentration measurements. The average of these five measurements was taken for each depth point. The sediment surface was determined manually based on the turning point in the slope of O 2 concentration with depth where O 2 started to become depleted. SCOC was determined from Fick’s first law of diffusion.

Microbiology sampling

Nodule and sediment samples for microbial community analyses were collected from the 5D experimental chambers. Approximately 30 g of sediment from each of the 0–2 cm and 2–5 cm horizons and 50 g of intact nodules were placed in separate sterile Whirlpak bags with a pre-sterilized spatula and then transferred to a −80 °C freezer. DNA from approximately 10 g of nodules and 250 mg of sediment were extracted using the Qiagen PowerMax soil and PowerSoil extraction kits, respectively. Extracted DNA was then shipped on dry ice to Laragen Inc. and sequenced using a proprietary in-house method. The V4 region of 16 S rRNA genes were amplified using the Earth Microbiome Project protocol 19 with the 515 F (5′‐GTGYCAGCMGCCGCGGTAA 20 ) and 806 R (5′-GGACTACNVGGGTWTCTAAT 21 ) primers. Raw fastq files were processed using a custom pipeline ( https://github.com/Boston-University-Microbiome-Initiative/BU16s ) built with QIIME 2020.2 ( https://www.nature.com/articles/s41587-019-0209-9 ). Adaptor sequences were removed using cutadapt ( https://doi.org/10.14806/ej.17.1.200 ), read truncation positions were determined by mineer (more below), amplicon sequence variants (ASVs) were generated using dada2 (trunc-len-r 20 ) ( https://doi.org/10.1038/nmeth.3869 ) and ASVs were clustered to 99% identity with the SILVA 132 database ( https://academic.oup.com/nar/article/42/D1/D643/1061236 ) using the vsearch cluster-features-closed-reference ( https://doi.org/10.7717/peerj.2584 ). Due to drops in sequencing quality, all reverse reads were truncated by 49 bases (from a length of 301 to 252) as determined by minERR, an algorithm for determining optimal sequence length based on sequence quality scores ( https://github.com/michaelsilverstein/mineer ). Family- and genus-level abundance was computed by summing the relative abundance of all ASVs with the same family/genus classification within each sample. Spearman correlations were then computed between family- and genus-level abundance and observed optode-derived total O 2 changes. Sequences have been archived at National Centre for Biotechnology Information GenBank under the Bioproject ID PRJNA1117483.

Polymetallic nodule surface area measurements

Photographs of the surface sediment and nodules in the chambers were imported into Image J. The outline of each nodule in each chamber photograph was then traced and the surface area of the nodule automatically calculated in Image J (assuming each surface nodule was flat in shape) and logged as an Image J file before being exported and saved as an Excel file.

Radiolysis O 2 production estimates

To estimate the potential radiolytic O 2 production, published concentrations of 238 U, 235 U, 232 Th, 40 K (refs. 22 , 23 , 24 , 25 , 26 ) in seawater were used (Supplementary Table 1 ). For nodules, 238 U, 235 U and 232 Th isotopes of three nodules from chamber experiments from the 5D cruise were measured by Multicollector-Inductively Coupled Plasma Mass Spectrometer using previously described methods 27 , 28 , 29 and averaged; 40 K values were derived from the literature 12 . Nodule and seawater contributions were calculated using a kinetic model developed by ref. 9 that incorporates 32 reactions (equation (1) in ref. 30 ). The nodule boundary layer was assumed to be fully integrated with the seawater, surpassing the respective ~23 to ~452 μm stopping power distance of alpha and beta particles used to model geologic materials 31 . Sediment radiolytic O 2 was calculated as half of the previously quantified H 2 production rates in equatorial Pacific subsurface sediment 32 , given the stoichiometry of water’s radiolytic decomposition (an equivalency that probably offers an overestimate of derived O 2 ). Contributions from these three components (nodules, sediment and seawater) were scaled by the benthic chamber’s size and contents to produce an estimate of 0.18 μmol l −1 of O 2 generated over 48 h according to the following expression.

Here (O 2 ) t is the mass (kg) of O 2 produced over a given time t (yr), Q iz is the mass (g) of the isotope, E a is the average energy (eV) released from the decay of one atom; G (O 2 ) is the radiation chemical yield of molecules per 100 eV of the radiation energy; M O2 is the O 2 molecular mass (g), A iz is the isotope atomic mass (g) and λ is the isotope-specific decay constant (y −1 ). The overall (O 2 ) t value summed the contributions from 238 U, 235 U, 232 Th and 40 K across water, nodule and sediment sources.

Electrochemistry measurements

Voltage potentials were measured using a Keithley DMM6500 digital multimeter on nodules previously collected by coring in the UK1, NORI-D and BGR license areas. Nodules were initially immersed for seven days in Instant Ocean artificial seawater (salinity 35). To measure the potentials, two electrodes (platinum wire, 99.9% purity) were first washed in perchloric acid, rinsed in Milli-Q water and dried before being attached to alligator clamps attached to the multimeter. The platinum wires were then immersed in Instant Ocean artificial seawater in a glass petri dish to measure background voltages (0.003 ± 0.001 V, SE, n  = 17) until stable. Once stable, a nodule was placed in the petri dish and the platinum probes placed on the nodule at random locations, ensuring contact in one of two ways. We either carefully drilled a hole into some nodules so one platinum wire could be fixed inside it while the second platinum wire was firmly pressed against the nodule surface using a clamp. Alternatively, the platinum wires were pressed firmly against two different spots on the nodule surface and held in place using a clamp. Voltages were then recorded for 1–2 min until the signal was stable. This procedure was repeated up to 20 times in different randomly selected regions of the nodules depending on their size. Measurements were undertaken on 12 nodules at 21 °C ( n  = 153) and a single control rock composed of metamorphosed carbonate ( n  = 10). Two nodules from UK1 were also retested after being cooled to 5 °C ( n  = 18) by placing them in Instant Ocean water in a refrigerator overnight. Voltage potentials ( n  = 20) between two nodules were measured using four nodules collected from UK1. Potentials measured during each measurement were averaged and corrected for the background seawater voltage measured using only Instant Ocean seawater in the absence of a nodule. Measured resistances inside some of the nodules that were broken up were in the kΩ to 100s of kΩ range, though it is unclear if these resistivities change at the nano- or microscale requiring further investigation.

Geochemistry modelling

The chemical stability and solubility of manganese (IV) oxide (birnessite) to dissolved Mn 2+ as a function of pH and O 2 activity was modelled using the Geochemist Workbench Professional (version 12) software, with the in-built and internally consistent THERMO database. The conditions used for generating the phase diagram (Extended Data Fig. 5 ) represent bottom seawater as measured in the eastern CCZ with a temperature of 1.6 °C and chlorine and manganese concentrations of 0.55 M Cl and 2e −10  M Mn, respectively.

Ex situ core incubations

Opportunistic ex situ experiments were undertaken during the 5D cruise using sediment cores retrieved by a multi-corer from the CTA area (Extended Data Fig. 1 ). Immediately after the multi-corer arrived back at the surface, cores were removed and transferred to a cold lab held at in situ temperature. The cores were then exposed to the following five treatments (administered using a 60 ml syringe), which included (1) Na 2 HCO 3 (0.3 μM final concentration, n  = 3), (2) NH 4 Cl (10 μM final concentration, n  = 3) and (3) NH 4 Cl (50 μM final concentration, n  = 3), (4) 0.3 μM Na 2 HCO 3  + 10 μM NH 4 Cl (final concentration, n  = 3) and (5) HgCl 2 (1.1 μM final concentration, n  = 3). No-injection controls ( n  = 3) were also performed and separate core experiments in which four nodules were incubated for 48 h by themselves with no additions. After addition, the water phase of each core was stirred and a 50-ml sample of top water was taken for microWinkler analysis (as above). Stoppers were then placed on the top of the cores, ensuring no air bubbles were present. The stoppers were secured tightly and the cores fully submerged in a large bucket containing 0.45-µm-filtered, cold, surface seawater (salinity 35). The bucket was covered with five black plastic bags and secured in the cold room with the lights turned off. After 48 h, the cores were removed from the bucket, and the cores were inspected for the presence of air bubbles. Only one core, a HgCl 2 treatment, had a gas bubble beneath the bung, which was rejected from further analysis, leaving n  = 2 for this treatment. The other cores were then re-sampled for dissolved O 2 and analysed as before. Core-specific water volume measurements were used together with the change in O 2 concentration to calculate the total net O 2 change per core.

To determine if our ex situ DOP detection was affected by intrusion of O 2 from the atmosphere into the core tube, two controls were performed: a shipboard test with an O 2 microprofiler and a lab-based test using the Winkler method. Shipboard, a clean core tube was filled with Milli-Q water and sparged with N 2 for 10 min before beginning the test. A Metrohm 8663 Multimeter was inserted through a predrilled hole in the rubber stopper, allowing for O 2 concentration to be recorded every 5 s. An increase from 39 to 69 µmol l −1 was observed over ~5 h, corresponding to a rate of 0.14 mmol m −2  d −1 or 4% of the 3.5 mmol m −2  d −1 mean net DOP measured in the ex situ experiments. Back in the home laboratory, three of the original core tubes were filled with 4 °C, 0.2-µm-filtered artificial seawater (salinity 35) and sparged with N 2 for 8 min through a filtered pipette tip to achieve an initial dissolved O 2 concentration of ~100 µmol l −1 (for example, the approximate starting O 2 concentrations for the shipboard experiments). The tubes were sealed with rubber stoppers and electrical tape, being careful to avoid bubble formation. They were then submerged in a 32-gallon plastic garbage can of unfiltered seawater (O 2 concentration: 228.12 µmol l −1 ) in a dark cold room (8 °C) for 48 h. After 48 h, the tubes were quickly unsealed and analysed one at a time to prevent additional O 2 dissolution from the air. A 50-ml sterile syringe was used to slowly collect 10 ml of seawater from the centre of the core tube, being sure to avoid bubble entrainment into the syringe. The sample was carefully expelled into a 10-ml reaction vial and fixed using the adjusted values for a 10-ml sample according to a volume-scaled Winkler titration protocol 33 and the reagents from the LaMotte Dissolved Oxygen Test Kit. The fixation of each collected sample was done in less than 2 min in a fume hood. Dissolved O 2 increased by 0.11 mmol m −2  d −1 during the 48 h, which corresponds to between 3.2% of the mean net DOP rate observed in the ex situ experiments (3.5 mmol m −2  d −1 ). Both of our control experiments provide high confidence that the diffusion of external O 2 into the core tubes did not cause the O 2 production measured in the ex situ core incubations.

Calculations to quantify intrusion of O 2 from the polyoxymethylene chambers and lids

Oxygen intrusion was estimated from Stephens 34 who calculated that 20.66 µmol l −1 of O 2 could diffuse out of 428 cm 2 of polyoxymethylene plastic when immersed for 48 h in hypoxic water (O 2 diffusion rate: 0.02 µmol O 2  cm −2  d −1 ). To determine the total area of plastic that would be available for diffusion (869–1,584 cm 2 ), we added the surface area of the lid to the surface area of the four walls that would be exposed at the seafloor (based on the depth of the water phase—above). The minimum and maximum areas available for diffusion were multiplied by 0.02 µmol O 2  cm −2  d −1 to estimate that 41.9–76.5 µmol O 2  l −1 would diffuse out of the polyoxymethylene chamber walls and lid in 48 h under hypoxic conditions. Thus, we are highly confident that O 2 leakage from the plastic chambers could not replicate the high O 2 concentration seen in some of our oxygenated experiments (Fig. 1 ).

Data availability

Source data are provided with this paper. These data are also available via Dryad at https://doi.org/10.5061/dryad.tdz08kq6w (ref. 35 ), and geological samples were exported in accordance with relevant permits. The nucleotide sequences generated by metagenome sequencing have been deposited in the National Centre for Biotechnology Information database under BioProject ID PRJNA1117483 .

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Acknowledgements

We would like to thank S. Wilson, E. Holsting, F. Mann and L. Carrera at Maersk Supply Service, the captain and crew of the research vessels ‘Maersk Launcher’ and ‘Island Pride’ for all their help preparing for the research expeditions and their excellent assistance at sea. We are grateful to R. Davis for help with the lander deployments and D. Anderson, M. Delgado and M. Cecchetto for help at sea. We thank Y. Maierhaba, C. Momjian and A. Shukla for their assistance with lab-based molecular analyses and R. Merrifield for his help with the electrochemistry analysis. We would like to acknowledge and give our thanks to K. M. Allen, M. Clarke, A. O’Sullivan, P. Clarke, L. Marsh and J. Smith for helping to initiate the research. The work was funded by The Metals Company Inc. through its subsidiary Nauru Ocean Resources Inc. (NORI). NORI holds exploration rights to the NORI-D contract area in the CCZ and is regulated by the International Seabed Authority and sponsored by the government of Nauru (A.K.S., C.W., W.B.H.). UK Seabed Resources funded the research expedition to the UK1 and OMS license areas in 2015 (A.K.S.), and the Gordon and Betty Moore Foundation provided funding for the research cruise to APEIs 1, 4 and 7 in 2018 (A.K.S.). Research support from the Natural Environment Research Council SMARTEX (Seabed Mining And Resilience To Experimental impact) project (grant number NE/T003537/1) and the European Commission project iAtlantic (grant number 818123) to A.K.S. is also acknowledged. We thank K. Mizell at the US Geological Survey for comments on our manuscript.

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Contributions

A.K.S., C.W., W.B.H. and J.J.M. generated the funding. A.K.S. conceived the study and led the benthic chamber lander investigations with A.J.S. A.K.S., A.J.S., D.S.W.d.J., C.A., P.S. and J.J.M. conducted the Winkler analysis and ex situ core incubations. A.K.S., A.J.S., D.S.W.d.J. and T.H. carried out the in situ oxygen optode calibrations and analysis. M.S., P.S. and J.J.M. led the microbiology analysis, whereas P.S. and R.L.E. undertook the radioactivity measurements and radiolysis calculations. A.K., S.F., T.K. and A.K.S. did the solubility assessments, and F.G. and A.K.S. undertook the electrochemistry measurements. A.K.S., J.J.M. and W.B.H. drafted the paper, and all authors contributed further ideas and approved the final version.

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Correspondence to Andrew K. Sweetman .

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Competing interests.

A.K.S., C.W. and W.B.H. received research support (funding) from The Metals Company, and A.K.S. also received research support from UK Seabed Resources to carry out part of the work. The Metals Company and UK Seabed Resources aided in the selection of study sites and operational scheduling at sea in a collaborative effort. S.F. and T.K. also work for the Federal Institute for Geoscience and Natural Resources, which holds exploration rights in the CCZ.

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Extended data

Extended data fig. 1 benthic chamber lander and multi-corer deployment locations across the ccz..

Benthic chamber lander (BCL) locations in APEIs 1, 4, and 7 (western CCZ), UK1 and OMS and NORI-D (stars) (a) and both areas (Collector Test Area or CTA and Preservation Reference Zone or PRZ) (b–d) of NORI-D in the central abyssal Pacific. The deployment location for the multi-corer (MUC) that sampled sediments for the ex situ experiments conducted during the 5D cruise is also shown (c).

Extended Data Fig. 2 Oxygen concentrations measured from water samples by Winkler titration during the NORI-D benthic chamber lander experiments.

Mean O 2 concentration (μmol L −1 ) measured by micro-Winkler analysis conducted on water samples that were collected periodically from the chambers through time (hr) under different treatments. The treatments were dead-algal biomass during expeditions 5D (A), 5E (E), and 7A (G), DIC + NH 4 + during expedition 5D (B), 0.45-μm filtered seawater during expedition 5D (C), and control (no injection) during expeditions 5D (D), 5E (F), and 7A (H). Each datapoint is the mean of two Winkler measurements.

Extended Data Fig. 3 Oxygen optode concentrations measured during benthic chamber lander experiments in the UK1 and OMS license areas and APEIs 1, 4, and 7.

Oxygen optode readings through time (hr) from 36-hour abyssal (4037-5216m) in-situ benthic chamber lander experiments conducted in the UK1 and OMS license areas in 2015 and APEIs 1, 4, and 7 in the western CCZ in June 2018. The experiments that were conducted were identical to those carried out at NORI-D. The O 2 concentrations recorded by the optodes in the 2015 and 2018 experiments were derived from factory calibrations undertaken 4–6 months prior to the expeditions as in-situ temperature could not be replicated onboard during the optode calibration process. As such, only relative changes in O 2 concentrations can be interpreted.

Extended Data Fig. 4 Bar chart showing total net O 2 production in ex situ sediment cores.

Mean total net O 2 production (μmol O 2 core −1 ) measured on sediment cores (n=1-3) exposed to a variety of treatments during 48-hr ex situ incubations that were carried out on the ship at in-situ temperature and in the dark during the 5D cruise. Oxygen production was determined from the difference in O 2 concentration of the water phase overlying the sediment between t = 0 hours and 48 hours accounting for the core volume. Error bars refer to ± 1 standard deviation. Individual fluxes from the ex-situ incubations are also shown as data points overlying the bars.

Extended Data Fig. 5 Phase stability and solubility of birnessite in seawater as a function of O 2 activity and pH.

The phase stability and solubility of birnessite (manganese [IV] oxide) in seawater as a function of O 2 activity and pH at a temperature of 1.6 °C, 0.55M Cl, and 2e −10 M Mn. The bold black line illustrates the phase boundary between birnessite and dissolved Mn 2+ ; the dashed lines the solubility of birnessite into seawater. The green point indicates the predominant manganese form that would be experienced at the highest pH that was measured in MUC cores, and the lowest O 2 condition (average bottom seawater); the red point indicates the predominant manganese form at the lowest pH (measured in MUC cores) and highest O 2 concentration measured in the in-situ benthic chamber experiments at NORI-D with the arrows showing their range. Under the latter conditions, a vanishing small amount of birnessite would dissolve into seawater to form Mn 2+ .

Supplementary information

Supplementary information.

Supplementary Table 1 and caption.

Source Data Fig. 1

Oxygen optode concentration (μmol l −1 ) data from benthic chamber lander experiments made during cruises 5D, 5E and 7A.

Source Data Fig. 2

Voltages (V) measured on the surface of nodules from the NORI-D, UK1 and BGR license areas.

Source Data Extended Data Fig. 2

Oxygen concentrations (μmol l −1 ) determined by Winkler titration on syringe samples collected from benthic chamber lander experiments made during cruises 5D, 5E and 7A.

Source Data Extended Data Fig. 3

Oxygen optode concentration (μmol l −1 ) data from benthic chamber lander experiments made during research cruises to the OMS, UK1 and APEI 1, 4 and 7 areas.

Source Data Extended Data Fig. 4

Oxygen concentrations (μmol l −1 ) determined by Winkler titration from the ex situ experiments conducted during the 5D cruise.

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Sweetman, A.K., Smith, A.J., de Jonge, D.S.W. et al. Evidence of dark oxygen production at the abyssal seafloor. Nat. Geosci. (2024). https://doi.org/10.1038/s41561-024-01480-8

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DOI : https://doi.org/10.1038/s41561-024-01480-8

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