scholarly journals Regulation of algal blooms in Antarctic Shelf Waters by the release of iron from melting sea ice

1997 ◽  
Vol 24 (20) ◽  
pp. 2515-2518 ◽  
Author(s):  
Peter N. Sedwick ◽  
Giacomo R. DiTullio
Keyword(s):  
Sea Ice ◽  
Algal Blooms ◽  
Antarctic Shelf

scholarly journals Influence of Seasonal Environmental Variables on the Distribution of Presumptive Fecal Coliforms around an Antarctic Research Station

2003 ◽  
Vol 69 (8) ◽  
pp. 4884-4891 ◽  
Author(s):  
Kevin A. Hughes
Keyword(s):  
Environmental Factors ◽  
Solar Radiation ◽  
Sea Ice ◽  
Fecal Coliform ◽  
Algal Blooms ◽  
Austral Summer ◽  
Fecal Coliforms ◽  
Late Winter ◽  
Research Station ◽  
The Antarctic

ABSTRACT Factors affecting fecal microorganism survival and distribution in the Antarctic marine environment include solar radiation, water salinity, temperature, sea ice conditions, and fecal input by humans and local wildlife populations. This study assessed the influence of these factors on the distribution of presumptive fecal coliforms around Rothera Point, Adelaide Island, Antarctic Peninsula during the austral summer and winter of February 1999 to September 1999. Each factor had a different degree of influence depending on the time of year. In summer (February), although the station population was high, presumptive fecal coliform concentrations were low, probably due to the biologically damaging effects of solar radiation. However, summer algal blooms reduced penetration of solar radiation into the water column. By early winter (April), fecal coliform concentrations were high, due to increased fecal input by migrant wildlife, while solar radiation doses were low. By late winter (September), fecal coliform concentrations were high near the station sewage outfall, as sea ice formation limited solar radiation penetration into the sea and prevented wind-driven water circulation near the outfall. During this study, environmental factors masked the effect of station population numbers on sewage plume size. If sewage production increases throughout the Antarctic, environmental factors may become less significant and effective sewage waste management will become increasingly important. These findings highlight the need for year-round monitoring of fecal coliform distribution in Antarctic waters near research stations to produce realistic evaluations of sewage pollution persistence and dispersal.

Sea-ice algal phenology in a warmer Arctic

2020 ◽  
Author(s):  
Letizia Tedesco ◽  
Marcello Vichi ◽  
Enrico Scoccimarro
Keyword(s):  
Sea Ice ◽  
Algal Blooms ◽  
Climate Models ◽  
Time Windows ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Biogeochemical Model ◽  
Biological Time ◽  
Algal Productivity ◽  
The Impact

<p>The Arctic sea-ice decline is among the most emblematic manifestations of climate change and is occurring before we understand its ecological consequences. We investigated future changes in algal productivity combining a biogeochemical model for sympagic algae with sea-ice drivers from an ensemble of 18 CMIP5 climate models. Model projections indicate quasi-linear physical changes along latitudes but markedly nonlinear response of sympagic algae, with distinct latitudinal patterns. While snow cover thinning explains the advancement of algal blooms below 66°N, narrowing of the biological time windows yields small changes in the 66°N to 74°N band, and shifting of the ice seasons toward more favorable photoperiods drives the increase in algal production above 74°N. These diverse latitudinal responses indicate that the impact of declining sea ice on Arctic sympagic production is both large and complex, with consequent trophic and phenological cascades expected in the rest of the food web.</p>

scholarly journals Large Diversity in Nitrogen- and Sulfur-Containing Compatible Solute Profiles in Polar and Temperate Diatoms

2020 ◽  
Vol 60 (6) ◽  
pp. 1401-1413
Author(s):  
H M Dawson ◽  
K R Heal ◽  
A Torstensson ◽  
L T Carlson ◽  
A E Ingalls ◽  
...  
Keyword(s):  
Organic Matter ◽  
Sea Ice ◽  
Algal Blooms ◽  
Dimethyl Sulfide ◽  
Compatible Solutes ◽  
Diatom Species ◽  
Variable Environment ◽  
Ice Melt ◽  
Isethionic Acid ◽  
Sulfur Containing

Synopsis Intense bottom-ice algal blooms, often dominated by diatoms, are an important source of food for grazers, organic matter for export during sea ice melt, and dissolved organic carbon. Sea-ice diatoms have a number of adaptations, including accumulation of compatible solutes, that allows them to inhabit this highly variable environment characterized by extremes in temperature, salinity, and light. In addition to protecting them from extreme conditions, these compounds present a labile, nutrient-rich source of organic matter, and include precursors to climate active compounds (e.g., dimethyl sulfide [DMS]), which are likely regulated with environmental change. Here, intracellular concentrations of 45 metabolites were quantified in three sea-ice diatom species and were compared to two temperate diatom species, with a focus on compatible solutes and free amino acid pools. There was a large diversity of metabolite concentrations between diatoms with no clear pattern identifiable for sea-ice species. Concentrations of some compatible solutes (isethionic acid, homarine) approached 1 M in the sea-ice diatoms, Fragilariopsis cylindrus and Navicula cf. perminuta, but not in the larger sea-ice diatom, Nitzschia lecointei or in the temperate diatom species. The differential use of compatible solutes in sea-ice diatoms suggests different adaptive strategies and highlights which small organic compounds may be important in polar biogeochemical cycles.

scholarly journals Sea-ice algal phenology in a warmer Arctic

2019 ◽  
Vol 5 (5) ◽  
pp. eaav4830 ◽  
Author(s):  
L. Tedesco ◽  
M. Vichi ◽  
E. Scoccimarro
Keyword(s):  
Sea Ice ◽  
Algal Blooms ◽  
Climate Models ◽  
Time Windows ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Biogeochemical Model ◽  
Biological Time ◽  
Algal Productivity ◽  
The Impact

The Arctic sea-ice decline is among the most emblematic manifestations of climate change and is occurring before we understand its ecological consequences. We investigated future changes in algal productivity combining a biogeochemical model for sympagic algae with sea-ice drivers from an ensemble of 18 CMIP5 climate models. Model projections indicate quasi-linear physical changes along latitudes but markedly nonlinear response of sympagic algae, with distinct latitudinal patterns. While snow cover thinning explains the advancement of algal blooms below 66°N, narrowing of the biological time windows yields small changes in the 66°N to 74°N band, and shifting of the ice seasons toward more favorable photoperiods drives the increase in algal production above 74°N. These diverse latitudinal responses indicate that the impact of declining sea ice on Arctic sympagic production is both large and complex, with consequent trophic and phenological cascades expected in the rest of the food web.

scholarly journals How are Antarctic planktonic microbial food webs and algal blooms affected by melting of sea ice? Microcosm simulations

1999 ◽  
Vol 20 ◽  
pp. 183-201 ◽  
Author(s):  
HC Giesenhagen ◽  
AE Detmer ◽  
J de Wall ◽  
A Weber ◽  
RR Gradinger ◽  
...  
Keyword(s):  
Sea Ice ◽  
Food Webs ◽  
Algal Blooms ◽  
Microbial Food Webs

scholarly journals The importance of turbulent ocean-sea ice nutrient exchanges for simulation of ice algal biomass and production with CICE6.1 and Icepack 1.2

2021 ◽  
Author(s):  
Pedro Duarte ◽  
Philipp Assmy ◽  
Karley Campbell ◽  
Arild Sundfjord
Keyword(s):  
Sea Ice ◽  
Algal Blooms ◽  
Molecular Diffusion ◽  
Critical Role ◽  
The Arctic ◽  
Algal Production ◽  
Biogeochemical Models ◽  
Momentum And Heat Transfer ◽  
Turbulent Momentum ◽  
Heat Exchanges

Abstract. Different sea-ice models apply unique approaches in the computation of nutrient diffusion between the ocean and the ice bottom, which are generally decoupled from the calculation of turbulent momentum and heat flux. Often, a simple molecular diffusion formulation is used. We argue that nutrient transfer from the ocean to sea ice should be as consistent as possible with momentum and heat transfer, since all these fluxes respond to varying forcing in a similar fashion. We hypothesize that biogeochemical models which do not consider such turbulent nutrient exchanges between the ocean and the sea-ice underestimate bottom-ice algal production. The Los Alamos Sea Ice Model (CICE + Icepack) was used to test this hypothesis by comparing simulations with molecular and turbulent diffusion of nutrients into the bottom of sea ice, implemented in a way that is consistent with turbulent momentum and heat exchanges. Simulation results support the hypothesis, showing a significant enhancement of ice algal production and biomass when nutrient limitation was relieved by bottom-ice turbulent exchange. Our results emphasize the potentially critical role of turbulent exchanges to sea ice algal blooms, and the importance of thus properly representing them in biogeochemical models. The relevance of this becomes even more apparent considering ongoing trends in the Arctic Ocean, with a predictable shift from light to nutrient limited growth of ice algae earlier in the spring, as the sea ice becomes more fractured and thinner with a larger fraction of young ice with thin snow cover.

scholarly journals The biogeochemical role of a microbial biofilm in sea ice

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Arnout Roukaerts ◽  
Florian Deman ◽  
Fanny Van der Linden ◽  
Gauthier Carnat ◽  
Arne Bratkic ◽  
...  
Keyword(s):  
Sea Ice ◽  
Algal Blooms ◽  
Nutrient Concentrations ◽  
Community Attachment ◽  
Microbial Biofilm ◽  
Autotrophic Biomass ◽  
High Concentrations ◽  
Landfast Sea Ice ◽  
Carbon Concentrations

A paradox is commonly observed in productive sea ice in which an accumulation in the macro-nutrients nitrate and phosphate coincides with an accumulation of autotrophic biomass. This paradox requires a new conceptual understanding of the biogeochemical processes operating in sea ice. In this study, we investigate this paradox using three time series in Antarctic landfast sea ice, in which massive algal blooms are reported (with particulate organic carbon concentrations up to 2,600 µmol L–1) and bulk nutrient concentrations exceed seawater values up to 3 times for nitrate and up to 19 times for phosphate. High-resolution sampling of the bottom 10 cm of the cores shows that high biomass concentrations coexist with high concentrations of nutrients at the subcentimeter scale. Applying a nutrient-phytoplankton-zooplankton-detritus model approach to this sea-ice system, we propose the presence of a microbial biofilm as a working hypothesis to resolve this paradox. By creating microenvironments with distinct biogeochemical dynamics, as well as favoring nutrient adsorption onto embedded decaying organic matter, a biofilm allows the accumulation of remineralization products (nutrients) in proximity to the sympagic (ice-associated) community. In addition to modifying the intrinsic physicochemical properties of the sea ice and providing a substrate for sympagic community attachment, the biofilm is suggested to play a key role in the flux of matter and energy in this environment.

scholarly journals Macro-nutrient concentrations in Antarctic pack ice: Overall patterns and overlooked processes

Elem Sci Anth ◽  
2017 ◽  
Vol 5 ◽  
Author(s):  
François Fripiat ◽  
Klaus M. Meiners ◽  
Martin Vancoppenolle ◽  
Stathys Papadimitriou ◽  
David N. Thomas ◽  
...  
Keyword(s):  
Microbial Community ◽  
Sea Ice ◽  
Silicic Acid ◽  
Algal Blooms ◽  
Inorganic Nitrogen ◽  
Ice Cores ◽  
Nutrient Concentrations ◽  
Phosphate Adsorption ◽  
Dissolved Inorganic Nitrogen ◽  
Pack Ice

Antarctic pack ice is inhabited by a diverse and active microbial community reliant on nutrients for growth. Seeking patterns and overlooked processes, we performed a large-scale compilation of macro-nutrient data (hereafter termed nutrients) in Antarctic pack ice (306 ice-cores collected from 19 research cruises). Dissolved inorganic nitrogen and silicic acid concentrations change with time, as expected from a seasonally productive ecosystem. In winter, salinity-normalized nitrate and silicic acid concentrations (C*) in sea ice are close to seawater concentrations (Cw), indicating little or no biological activity. In spring, nitrate and silicic acid concentrations become partially depleted with respect to seawater (C* < Cw), commensurate with the seasonal build-up of ice microalgae promoted by increased insolation. Stronger and earlier nitrate than silicic acid consumption suggests that a significant fraction of the primary productivity in sea ice is sustained by flagellates. By both consuming and producing ammonium and nitrite, the microbial community maintains these nutrients at relatively low concentrations in spring. With the decrease in insolation beginning in late summer, dissolved inorganic nitrogen and silicic acid concentrations increase, indicating imbalance between their production (increasing or unchanged) and consumption (decreasing) in sea ice. Unlike the depleted concentrations of both nitrate and silicic acid from spring to summer, phosphate accumulates in sea ice (C* > Cw). The phosphate excess could be explained by a greater allocation to phosphorus-rich biomolecules during ice algal blooms coupled with convective loss of excess dissolved nitrogen, preferential remineralization of phosphorus, and/or phosphate adsorption onto metal-organic complexes. Ammonium also appears to be efficiently adsorbed onto organic matter, with likely consequences to nitrogen mobility and availability. This dataset supports the view that the sea ice microbial community is highly efficient at processing nutrients but with a dynamic quite different from that in oceanic surface waters calling for focused future investigations.

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