Impacts of Temperature, CO2, and Salinity on Phytoplankton Community Composition in the Western Arctic Ocean

Sugie, Koji; Fujiwara, Amane; Nishino, Shigeto; Kameyama, Sohiko; Harada, Naomi

doi:10.3389/fmars.2019.00821

Cited by 43 publications

(25 citation statements)

References 84 publications

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“…Recent changes in the marine environment have a profound impact on the Arctic Ocean's biogeochemical cycle. For example, increasing water temperature directly influences biological activity and metabolism rates (Coello‐Camba & Agustí, 2017; Sugie et al, 2020). The increased amount of fresh water generated by melting sea ice and increased river runoff has enhanced the stratification in the ocean's upper layer (Frey et al, 2014; Screen & Simmonds, 2010; Timmermans et al, 2011), hindering the supply of nutrients from the deeper layers to the surface (Carmack et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Effects of Nitrogen Limitation on Phytoplankton Physiology in the Western Arctic Ocean in Summer

Gorbunov

Jung

et al. 2020

JGR Oceans

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Phytoplankton in the Arctic Ocean are subject to nitrogen limitation in the summer, however, how severely the nitrogen stress affects phytoplankton physiology remains largely unknown. In the summers of 2015-2018, we examined the distribution of phytoplankton photophysiological properties across two contrasting regions of the Arctic Ocean with distinctly different levels of nitrogen availability in the upper water column. We quantified the extent of nitrogen stress using a highly sensitive fluorescence induction and relaxation system to obtain continuous underway measurements and via discrete sample analyses of phytoplankton physiology, as well as nutrient enrichment incubations. The results revealed vast regions in the Chukchi Sea where phytoplankton photosynthesis was severely nitrogen-stressed. Thereby, the maximum quantum yield of photochemistry in photosystem II showed only a small decrease (12 ± 9%) relative to its nutrient-replete values, while the maximum photosynthetic electron transport rates under saturating irradiance were impaired to a greater extent (40 ± 17%). This phytoplankton photosynthesis response is indicative of a severe nitrogen limitation, which results in dramatic reduction in growth and net primary production rates. Nutrient enrichment incubations also revealed a marked increase in large-size phytoplankton growth (>10 μm) after the nitrogen stress was alleviated, suggesting that the larger cells were more susceptible to nitrogen stress. These results are important for understanding how regional nitrogen fluxes control variability in the primary production and phytoplankton community structure and how these processes might change with rapid climate changes in the Arctic Ocean. Plain Language Summary Nutrient availability is the main bottom-up controls of phytoplankton physiology and growth in the upper ocean. The distribution of nutrient limitation in the global ocean varies greatly in space and time, so phytoplankton responses to this factor are essential for understanding the marine ecosystem. Although nitrogen limitation was previously shown in the Arctic Ocean in the summer, how nitrogen stress affects phytoplankton physiology remains largely unknown. This study investigates, with high spatial resolution, the distribution of phytoplankton physiological status and quantifies the effects of nitrogen stress in the western Arctic Ocean. Our results revealed severe nitrogen limitation in the summer that results in dramatic reduction in growth and net primary production in this region of the ocean. Therefore, alterations in nitrogen fluxes along with climate change in the Arctic Ocean would be important for controlling phytoplankton growth and primary production in this region.

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Section: Introductionmentioning

confidence: 99%

Effects of Nitrogen Limitation on Phytoplankton Physiology in the Western Arctic Ocean in Summer

Gorbunov

Jung

et al. 2020

JGR Oceans

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“…For example, the probable adaptation patterns would benefit from a gene expression study to test patterns of acclimation, as recently exemplified in fish 80 complementing patterns observed for bacterial communities in the same samples 35 . Such data would feed into efforts to better understand and predict the impact of global warming, which could have a major impact on the polar biome community 81 . It has recently been suggested that advection by North Atlantic currents to the Arctic Ocean, combined with warming, will shift the distribution of phytoplankton poleward, leading to a restructuring of biogeography and complete communities 82 .…”

Section: Discussionmentioning

confidence: 99%

Equatorial to Polar genomic variability of the microalgae Bathycoccus prasinos

Leconte

Timsit

Delmont

et al. 2021

Preprint

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The importance of marine phytoplankton in food webs and biogeochemical cycles makes the study of prokaryotic and eukaryotic phytoplankton species essential to understand changes in the global ecosystem. As plankton is transported by ocean currents, its community composition varies. Some species are abundant in contrasting environments, which raises the question of the genomic basis of their adaptation. Here we exploit the cosmopolitan distribution of the eukaryotic picoalgae Bathycoccus prasinos to investigate its genomic variations among temperate and polar populations. Using multiple metagenomic data, we found that ~5% of genomic positions of B. prasinos are variable, with an overwhelming majority of biallelic patterns. Cold and temperate waters are clearly associated with changes in variant occurrences including striking differences at some non-synonymous positions of several genes. Data from transitional waters showed more balanced polymorphism at most of these positions. The comparison of mesophilic and psychrophilic gene variants of this species suggests that its adaptation to cold waters may involve few amino acid changes at positions of protein structures critical for physical and functional properties. These results provide new insights into the genomic diversity and temperature-associated amino acid changes of a cosmopolitan eukaryotic planktonic species.

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“…The Arctic Ocean in general is expected to be a 'hotspot' of ocean acidification (Orr et al, 2005;Sugie et al, 2020). Indeed, Chierici et al (2019) estimated continued CO 2 uptake by the ocean at the West Spitsbergen shelf and on the slope north of Svalbard.…”

Section: Ocean Acidification Perspectivesmentioning

confidence: 99%

Planktic Foraminiferal and Pteropod Contributions to Carbon Dynamics in the Arctic Ocean (North Svalbard Margin)

et al. 2021

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Planktic foraminifera and shelled pteropods are some of the major producers of calcium carbonate (CaCO3) in the ocean. Their calcitic (foraminifera) and aragonitic (pteropods) shells are particularly sensitive to changes in the carbonate chemistry and play an important role for the inorganic and organic carbon pump of the ocean. Here, we have studied the abundance distribution of planktic foraminifera and pteropods (individuals m–3) and their contribution to the inorganic and organic carbon standing stocks (μg m–3) and export production (mg m–2 day–1) along a longitudinal transect north of Svalbard at 81° N, 22–32° E, in the Arctic Ocean. This transect, sampled in September 2018 consists of seven stations covering different oceanographic regimes, from the shelf to the slope and into the deep Nansen Basin. The sea surface temperature ranged between 1 and 5°C in the upper 300 m. Conditions were supersaturated with respect to CaCO3 (Ω > 1 for both calcite and aragonite). The abundance of planktic foraminifera ranged from 2.3 to 52.6 ind m–3 and pteropods from 0.1 to 21.3 ind m–3. The planktic foraminiferal population was composed mainly of the polar species Neogloboquadrina pachyderma (55.9%) and the subpolar species Turborotalita quinqueloba (21.7%), Neogloboquadrina incompta (13.5%) and Globigerina bulloides (5.2%). The pteropod population was dominated by the polar species Limacina helicina (99.6%). The rather high abundance of subpolar foraminiferal species is likely connected to the West Spitsbergen Current bringing warm Atlantic water to the study area. Pteropods dominated at the surface and subsurface. Below 100 m water depth, foraminifera predominated. Pteropods contribute 66–96% to the inorganic carbon standing stocks compared to 4–34% by the planktic foraminifera. The inorganic export production of planktic foraminifera and pteropods together exceeds their organic contribution by a factor of 3. The overall predominance of pteropods over foraminifera in this high Arctic region during the sampling period suggest that inorganic standing stocks and export production of biogenic carbonate would be reduced under the effects of ocean acidification.

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Impacts of Temperature, CO2, and Salinity on Phytoplankton Community Composition in the Western Arctic Ocean

Cited by 43 publications

References 84 publications

Effects of Nitrogen Limitation on Phytoplankton Physiology in the Western Arctic Ocean in Summer

Effects of Nitrogen Limitation on Phytoplankton Physiology in the Western Arctic Ocean in Summer

Equatorial to Polar genomic variability of the microalgae Bathycoccus prasinos

Planktic Foraminiferal and Pteropod Contributions to Carbon Dynamics in the Arctic Ocean (North Svalbard Margin)

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