Reactive Oxygen Species Dynamics in Marine Environments

Reactive oxygen species (ROS) such as superoxide and hydrogen peroxide are transient but influential constituents of marine waters, bridging biological metabolism and elemental cycling. These molecules arise through photochemical reactions at the sea surface, as by-products of phytoplankton photosynthesis, and via light-independent processes mediated by bacteria, corals and sponges. Once formed, ROS drive redox transformations of trace metals, regulate microbial community interactions and modulate nutrient bioavailability. Spatially and temporally, ROS levels vary from picomolar to nanomolar concentrations, with hotspots occurring in productive coastal zones, oxygen minimum regions and benthic habitats. A fuller understanding of ROS dynamics reveals their dual role as signalling agents at low concentrations and stress inducers at elevated levels, with implications for carbon cycling, pollutant degradation and ecosystem health under changing climatic conditions.

Research from Nature Portfolio

Deep‐ocean surveys of hydrogen peroxide across multiple basins have uncovered persistent nanomolar concentrations well below the photic zone, demonstrating that photochemistry alone cannot account for observed levels. Evidence points to dark, pelagic production—most likely of microbial origin—sufficient to sustain deep‐sea H2O2. This work compels a reappraisal of redox sourcing in the abyssal ocean and highlights the role of subsurface microbial communities in global ROS budgets.

Reactive Oxygen Species Dynamics in Marine Environments publication trend

The graph below shows the total number of articles in reactive oxygen species dynamics in marine environments across all publications each year (not limited to Nature Index journals).

Technical terms

Reactive oxygen species (ROS): Chemically reactive molecules derived from oxygen, including radicals and peroxides, that mediate redox processes in seawater.

Superoxide: The one-electron reduction product of molecular oxygen (O2•−), notable for rapid redox cycling and potential signalling functions.

Hydrogen peroxide: A non-radical ROS (H2O2) capable of diffusing through cell membranes and driving oxidative transformations of organic and inorganic substrates.

Photic zone: The upper layer of the ocean penetrated by sunlight, where photochemical ROS production and photosynthesis occur.

Extracellular production: The release of ROS into ambient seawater by organisms, influencing local redox conditions and biogeochemical cycles.

References

1. Corals and sponges are hotspots of reactive oxygen species in the deep sea. PNAS Nexus (2023).
2. Production of extracellular reactive oxygen species by phytoplankton: past and future directions. Journal of Plankton Research (2018).
3. The Influence of Extracellular Superoxide on Iron Redox Chemistry and Bioavailability to Aquatic Microorganisms. Frontiers in Microbiology (2012).
4. Hydrogen peroxide in deep waters from the Mediterranean Sea, South Atlantic and South Pacific Oceans. Scientific Reports (2017).
5. Spatial Heterogeneity in Particle‐Associated, Light‐Independent Superoxide Production Within Productive Coastal Waters. Journal of Geophysical Research - Oceans (2020).
6. Heterotrophic Bacteria Exhibit a Wide Range of Rates of Extracellular Production and Decay of Hydrogen Peroxide. Frontiers in Marine Science (2020).