首页|Nitrogen-limitation exacerbates the impact of ultraviolet radiation on the coccolithophore Gephyrocapsa oceanica

Nitrogen-limitation exacerbates the impact of ultraviolet radiation on the coccolithophore Gephyrocapsa oceanica

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  • NSTL
  • Elsevier
To investigate effects of UV radiation (UVR, 280-400 nm) on coccolithophorids under nutrient-limited conditions, we grew Gephyrocapsa oceanica to determine its resilience to consecutive daily short-term exposures to +UVR (irradiances > 295 nm) under a range of nitrate availabilities (100, 24, 12, 6 and 3 mu M). +UVR alone significantly hampered the growth of G. oceanica, with the synergistic negative effects of +UVR and N-limitation being about 58% and 22% greater than under UVR or N-limitation alone, respectively. Most 3 mu M nitrate cultures died, but those exposed to UVR succumbed sooner. This was due to a failure of photoprotection and repair mechanisms under low N-availability with exposures to UVR. Additionally, the UVR-induced inhibition of the effective quantum yield of photosystem II (PSII) was significantly higher and was further aggravated by N limitation. The algal cells increased photoprotective pigments and UV-absorbing compounds as a priority rather than using calcification for defense against UVR, indicating a trade-off in energy and resource allocation. Our results indicate the negative effects of UVR on coccolithophorid growth and photosynthesis, and highlight the important role of N availability in defense against UVR as well as high PAR. We predict that enhanced N -limi-tation in future surface oceans due to warming-induced stratification will exacerbate the sensitivity of G. oceanica to UVR, while coccolithophores can be potentially more susceptible to other environmental stresses due to increased levels of nutrient limitation.

CalcificationCoccolithophoreGrowthGephyrocapsa oceanicaNitrate-limitationPhotosynthesisPhytoplanktonUVRSOLAR UV-RADIATIONEMILIANIA-HUXLEYIMARINE-PHYTOPLANKTONLIGHT-INTENSITYINDUCED PHOTOINHIBITIONENVIRONMENTAL CONTROLSCALCIFICATION RATESORGANIC-CARBONCO2 FIXATIONAMINO-ACIDS

Jiang, Xiaowen、Zhang, Yong、Hutchins, David A.、Gao, Kunshan

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Xiamen Univ

Univ Southern Calif

2022

10.1016/j.jphotobiol.2021.112368

Journal of Photochemistry and Photobiology

Journal of Photochemistry and Photobiology

ISSN：1011-1344
年,卷(期)：2022.226
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