Effects of salinity changes on coastal Antarctic phytoplankton physiology and assemblage composition

Hernando, Marcelo Pablo; Schloss, Irene R; Malanga, Gabriela; Almandoz, Gastón O.; Ferreyra, Gustavo A.; Aguiar, María Belén; Puntarulo, Susana

doi:10.1016/j.jembe.2015.02.012

Cited by 70 publications

(47 citation statements)

References 67 publications

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“…Navicula, Nitzschia, etc.) have greater tolerance to low salinities than large diatoms (Hernando et al 2015), such that the phytoplankton response to glacial meltwater inputs may differ depending on community composition and the timing of inputs relative to bloom progression.…”

Section: Phytoplankton and Microbial Community Dynamicsmentioning

confidence: 99%

“…An acidification-driven shift towards larger diatoms would act against the proposed shift towards smaller diatoms, haptophytes and cryptophytes driven by changing ice distributions and freshwater inputs (e.g. Hernando et al 2015;Rozema et al 2017a;Schofield et al 2017). As such, the phytoplankton response to competing physical and biological forcings along the WAP could vary significantly over time and space, compounding variability in the forcings themselves.…”

Section: Ecosystem Responses To Ocean Acidificationmentioning

confidence: 99%

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Variability and change in the west Antarctic Peninsula marine system: Research priorities and opportunities

Henley

Schofield

Hendry

et al. 2019

Progress in Oceanography

112

115

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The west Antarctic Peninsula (WAP) region has undergone significant changes in temperature and seasonal ice dynamics since the mid-twentieth century, with strong impacts on the regional ecosystem, ocean chemistry and hydrographic properties. Changes to these long-term trends of warming and sea ice decline have been observed in the 21 st century, but their consequences for ocean physics, chemistry and the ecology of the high-productivity shelf ecosystem are yet to be fully established. The WAP shelf is important for regional krill stocks and higher trophic levels, whilst the degree of variability and change in the physical environment and documented biological and biogeochemical responses make this a model system for how climate and sea ice changes might restructure high-latitude ecosystems. Although this region is arguably the best-measured and bestunderstood shelf region around Antarctica, significant gaps remain in spatial and temporal data capable of resolving the atmosphere-ice-ocean-ecosystem feedbacks that control the dynamics and evolution of this complex polar system. Here we summarise the current state of knowledge regarding the key mechanisms and interactions regulating the physical, biogeochemical and biological processes at work, the ways in which the shelf environment is changing, and the ecosystem response to the changes underway. We outline the overarching cross-disciplinary priorities for future research, as well as the most important discipline-specific objectives. Underpinning these priorities and objectives is the need to better-define the causes, magnitude and timescales of variability and change at all levels of the system. A combination of traditional and innovative approaches will be critical to addressing these priorities and developing a coordinated observing system for the WAP shelf, which is required to detect and elucidate change into the future.

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Section: Phytoplankton and Microbial Community Dynamicsmentioning

confidence: 99%

Section: Ecosystem Responses To Ocean Acidificationmentioning

confidence: 99%

Variability and change in the west Antarctic Peninsula marine system: Research priorities and opportunities

Henley

Schofield

Hendry

et al. 2019

Progress in Oceanography

112

115

View full text Add to dashboard Cite

show abstract

“…This suggests important localized forcings. Similar comparative studies are not available for other areas of the Southern Ocean, which are differentially affected by sea ice, glacial meltwater (Hernando et al, 2015), iron availability, and other stressors such as CO 2 increase and the consequent ocean acidification (Hoppe et al, 2013;Trimborn et al, 2013Trimborn et al, , 2017Hancock et al, 2018). Other than phytoplankton, bulk community composition and a deeper understanding of the microbial realm, including bacteria, archaea, and viruses, and the role of recalcitrant dissolved organic matter (microbial carbon pump, Jiao et al, 2010) are essential to the food-web carbon flux as well as to the ocean-carbon pump and CO 2 sequestration.…”

Section: Theme 6: Impacts Of Global Change On Southern Ocean Ecosystemsmentioning

confidence: 99%

Delivering Sustained, Coordinated, and Integrated Observations of the Southern Ocean for Global Impact

et al. 2019

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Newman et al. The Southern Ocean Observing System time series of key variables, and delivers the greatest impact from data to all key end-users. Although the Southern Ocean remains one of the least-observed ocean regions, enhanced international coordination and advances in autonomous platforms have resulted in progress toward sustained observations of this region. Since 2009, the Southern Ocean community has deployed over 5700 observational platforms south of 40 • S. Large-scale, multi-year or sustained, multidisciplinary efforts have been supported and are now delivering observations of essential variables at space and time scales that enable assessment of changes being observed in Southern Ocean systems. The improved observational coverage, however, is predominantly for the open ocean, encompasses the summer, consists of primarily physical oceanographic variables, and covers surface to 2000 m. Significant gaps remain in observations of the ice-impacted ocean, the sea ice, depths >2000 m, the air-ocean-ice interface, biogeochemical and biological variables, and for seasons other than summer. Addressing these data gaps in a sustained way requires parallel advances in coordination networks, cyberinfrastructure and data management tools, observational platform and sensor technology, twoway platform interrogation and data-transmission technologies, modeling frameworks, intercalibration experiments, and development of internationally agreed sampling standards and requirements of key variables. This paper presents a community statement on the major scientific and observational progress of the last decade, and importantly, an assessment of key priorities for the coming decade, toward achieving the SOOS vision and delivering essential data to all end-users.

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“…This process starts in June when ablation intensifies and ends in September when the air temperature drops, leading to a significant decrease in the inflow of suspended sediments and the volume of fresh water (Węsławski et al 1995). There are also known cases of mass mortality of krill (Węsławski and Legżyńska 1998), phytoplankton (Hernando et al 2015), and amphipods (Eiane and Daase 2002) as a result of osmotic shock resulting from the direct proximity of the glacier or the glacial river. On the other hand, previous research demonstrates the high tolerance of the krill Euphausia superba to a wide salinity range from 25 to 45 (Aareset and Torres 1989).…”

Section: Sedimentation and Glacier Trapmentioning

confidence: 99%

Plankton or benthos: where krill belongs in Spitsbergen fjords? (Svalbard Archipelago, Arctic)

2019

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This study couples observations of krill (Thysanoessa inermis, Thysanoessa longicaudata, Thysanoessa rashii) from Tucker trawl nets and cameras, trying to test hypothesis that in the glaciated fjords of Svalbard most of the euphausiids biomass is located in near-bottom habitat and explains why in this region there are a substantial part of the krill population near the sea floor. Photographic material from the summers of 2013-2017 shows large numbers of near-bottom euphausiids (39% of the total krill biomass in Hornsund and 41% in Kongsfjorden), which reached a maximum density of 751 ± 224 indiv. m −3 in Kongsfjorden, 731 ± 198 indiv. m −3 in Hornsund, and 426 ± 124 indiv. m −3 in Adventfjorden. Regional distribution of near-bottom aggregations of krill seem to be associated with close proximity to the glacier front rather than with depth. The highest densities were located in the glacial bays. Where and why these aggregations occur is probably complicated and dependent on many environmental factors acting together. However, the dominant factors seem to be sedimentation and estuarine circulation. No krill aggregations were found during the winter cruise. The dominating species was T. inermis which made up 90% of the community. Other krill species-T. rashii and T. longicaudata, made up 6% and 4%, respectively. In the summer, aggregations of other macrozooplankton were also observed: amphipods of the genus Themisto and chaetognaths of the genera Eukrohnia and Parasagitta. Euphausiid densities in the water column (from Tucker trawl hauls) were an order of magnitude lower (0.33 indiv. m −3 for Kongsfjorden and 0.61 indiv. m −3 for Hornsund) than those of the near-bottom aggregations observed on cameras system. At most stations, the krill exhibited a behaviour, known as "nose diving" in the sediment, which is likely related to feeding. Observation of this phenomenon may indicate that krill (mostly T. inermis), found near the bottom of Spitsbergen fjords, is looking for food there. Near-bottom aggregations of zooplankton, mainly krill, are common in glacial bays and can be important in the function of the fjord ecosystem. Our research proves that the zooplankton biomass can be highly underestimated if only Tucker trawl sampling is done, due to neglecting the near-bottom layer in this type of method.

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Effects of salinity changes on coastal Antarctic phytoplankton physiology and assemblage composition

Cited by 70 publications

References 67 publications

Variability and change in the west Antarctic Peninsula marine system: Research priorities and opportunities

Variability and change in the west Antarctic Peninsula marine system: Research priorities and opportunities

Delivering Sustained, Coordinated, and Integrated Observations of the Southern Ocean for Global Impact

Plankton or benthos: where krill belongs in Spitsbergen fjords? (Svalbard Archipelago, Arctic)

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