Impact of Ultraviolet Radiation on Marine Primary Production

Ultraviolet radiation (UVR) exerts a complex influence on marine primary production by directly affecting the photosynthetic machinery of phytoplankton and indirectly modifying community structure and biogeochemical cycles. UVR spans wavelengths from 280 to 400 nm and penetrates the water column to depths governed by optical properties and stratification. At the cellular level, exposure to UV-B (280–315 nm) induces photoinhibition through damage to photosystem II reaction centres, DNA lesions and oxidative stress, while UV-A (315–400 nm) can generate reactive oxygen species that impair metabolic functions. Phytoplankton deploy various photoprotective strategies, including synthesis of mycosporine-like amino acids and activation of repair mechanisms, but these incur energetic costs that can reduce net carbon fixation. Moreover, UVR interacts with nutrient availability, water column mixing and temperature to reshape species composition, often favouring smaller cells with higher surface-to-volume ratios or mixotrophic modes of nutrition. These dynamics influence global carbon sequestration, since marine phytoplankton account for roughly half of planetary photosynthetic activity. Changes in ozone concentration, climate-driven stratification and increased water transparency in oligotrophic regions may exacerbate UVR exposure, with potential feedbacks on marine food webs and the ocean’s role in regulating atmospheric CO₂.

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Impact of Ultraviolet Radiation on Marine Primary Production publication trend

The graph below shows the total number of articles in impact of ultraviolet radiation on marine primary production across all publications each year (not limited to Nature Index journals).

Technical terms

Ultraviolet radiation (UVR): Electromagnetic radiation in the 280–400 nm range that can penetrate water and affect biological processes.

Photosynthetically active radiation (PAR): The 400–700 nm waveband utilised by phytoplankton for photosynthesis, often interacting with UVR in penetration and attenuation.

Photoinhibition: A reduction in photosynthetic efficiency caused by damage to the photosynthetic apparatus under high light or UVR exposure.

Biological weighting function (BWF): A mathematical representation of the relative effectiveness of different UV wavelengths in causing photoinhibitory damage to organisms.

Mixotrophy: A nutritional strategy combining photoautotrophy and heterotrophy, enabling organisms to supplement photosynthesis with ingestion of organic matter.

References

1. Interactive Effect of UVR and Phosphorus on the Coastal Phytoplankton Community of the Western Mediterranean Sea: Unravelling Eco-Physiological Mechanisms. PLOS ONE (2015).
2. UV effects on the primary productivity of picophytoplankton: biological weighting functions and exposure response curves of Synechococcus. Biogeosciences (2014).
3. Contrasting Responses of Marine and Freshwater Photosynthetic Organisms to UVB Radiation: A Meta-Analysis. Frontiers in Marine Science (2017).