Vertical Fine Structure of Particulate Matter and Nutrients in Sea Ice of the High Arctic

1990 ◽  
Vol 47 (7) ◽  
pp. 1348-1355 ◽  
Author(s):  
Ralph E. H. Smith ◽  
W. Glen Harrison ◽  
Leslie R. Harris ◽  
Alex W. Herman
Keyword(s):  
Fine Structure ◽  
Particulate Matter ◽  
Sea Ice ◽  
Chlorophyll A ◽  
Light Availability ◽  
High Arctic ◽  
Inorganic Nutrient ◽  
Nutrient Concentrations ◽  
Ice Algae ◽  
Nitrogen And Phosphorus

The vertical fine structure of particulate matter and inorganic nutrients through the bottom layers of sea ice was determined at a site in the Canadian high arctic. Intense vertical gradients of chlorophyll a, nitrate, ammonium, nitrite, phosphate, and silicate developed in the lower 6 cm of the ice as ice algae attained standing crops of 250 mg∙m−2 (up to 60 mg∙L−1) of chlorophyll a. Pigment and inorganic nutrient concentrations were closely correlated, and pools of inorganic nutrient were shown to exist in the particulate matter, suggesting that the extremely high dissolved nutrient concentrations in the bottom ice (e.g. up to 400 μmol∙L−1 nitrate) were derived at least in part from leakage of algal intracellular pools. Nitrogen and phosphorus were present in excess of algal needs, but silicon may not have been. The ratios of particulate organic carbon to chlorophyll a and to particulate organic nitrogen increased from the ice–water interface upwards, consistent with a physiological response of the ice algae to the strong corresponding gradient of light availability. Although spatially compact, the assemblage of algae in the bottom ice inhabits a highly stratified environment.

scholarly journals Structural changes of the phytoplankton and epiphyton in an urban hypereutrophic reservoir

2016 ◽  
Vol 28 (0) ◽  
Author(s):  
Lucineide Maria Santana ◽  
Carla Ferragut
Keyword(s):  
Species Richness ◽  
Water Flow ◽  
Structural Changes ◽  
Light Availability ◽  
Temporal Changes ◽  
Nutrient Concentrations ◽  
Nitrogen And Phosphorus ◽  
Nutrients Availability ◽  
High Species Richness ◽  
Different Depths

Abstract: Aim This study evaluated the temporal changes of phytoplankton and epiphyton structure and their relationships with limnological factors in an urban hypereutrophic reservoir (Rasgão Reservoir, Brazil). Methods We collected water sample and phytoplankton in different depths at two sites (dam and near tributary input) in summer and winter 2010. Epiphyton on Salvinia spp. was sampled only at site near the tributary input. We determined limnological variables and structural attributes (species composition, density, biovolume, descriptors species, diversity) for both communities. Results Phytoplankton density and epiphyton density and biovolume were higher in the winter (dry season), which occurred the higher nutrient concentrations and lower water flow. Chlorophyceae was dominant in the phytoplankton in both period and Cyanobacteria was the second most abundant class in the winter. In the epiphyton, Bacillariophyceae was dominant in the summer and Cyanobacteria in the winter. The increase in light availability and water flow can have provided high species richness and diversity in the summer. Conclusion Temporal changes in the structure of phytoplankton and epiphyton on Salvinia were more related to increased nutrients availability (nitrogen and phosphorus) and flow variations in a hypereutrophic reservoir.

scholarly journals Production of Chromophoric Dissolved Organic Matter (CDOM) in Laboratory Cultures of Arctic Sea Ice Algae

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 926
Author(s):  
Guiju Li ◽  
Huixiang Xie ◽  
Guisheng Song ◽  
Michel Gosselin
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Sea Ice ◽  
Chlorophyll A ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Chromophoric Dissolved Organic Matter ◽  
Ice Algae ◽  
Production Rates ◽  
Arctic Sea

Chromophoric dissolved organic matter (CDOM) is highly enriched in bottom sea ice in the Arctic during ice algal blooms, giving rise to multifaceted ecological implications in both the sea ice and the underlying seawater. We conducted laboratory culture incubations to assess the potential role of ice algae in the accumulation of CDOM in Arctic sea ice. Non-axenic monocultures of Attheya septentrionalis and Nitzschia frigida and a natural ice algal assemblage (NIAA) were grown at 4 °C in an f/2 medium under cool white fluorescent light. Culture samples were collected several days apart throughout the exponential, stationary, and senescent phases, and analyzed for CDOM absorbance, chlorophyll a, and bacterial cell abundance. The cultures displayed apparent specific growth rates of algal and bacterial cells comparable to those in the field. Accumulations of CDOM were observed in all cultures during the time-course incubations, with the senescent phase showing the largest accumulations and the highest production rates. The senescent-phase production rate for NIAA was ~40% higher than that for A. septentrionalis. The chlorophyll a-normalized CDOM production rates in the cultures are comparable to those reported for Arctic first-year sea ice. The absorption spectra of CDOM in the cultures exhibited characteristic short-ultraviolet shoulders similar to those previously identified in sea ice. This study demonstrates that ice algal-derived CDOM can account for the springtime accumulation of CDOM in Arctic sea ice.

Night metabolism of recent photosynthate by sea ice algae in the high Arctic

1990 ◽  
Vol 107 (2) ◽  
pp. 255-261 ◽  
Author(s):  
R. E. H. Smith ◽  
P. Clement ◽  
E. J. Head
Keyword(s):  
Sea Ice ◽  
High Arctic ◽  
Ice Algae ◽  
Sea Ice Algae

scholarly journals Photobiological Effects on Ice Algae of a Rapid Whole-Fjord Loss of Snow Cover during Spring Growth in Kangerlussuaq, a West Greenland Fjord

2021 ◽  
Vol 9 (8) ◽  
pp. 814
Author(s):  
Brian K. Sorrell ◽  
Ian Hawes ◽  
Tanja Stratmann ◽  
Lars Chresten Lund-Hansen
Keyword(s):  
Sea Ice ◽  
Snow Cover ◽  
Climate Models ◽  
Light Availability ◽  
Fluorescence Yield ◽  
Ice Algae ◽  
West Greenland ◽  
Complex Interactions ◽  
Wind Event ◽  
Loss Event

Snow cover on sea ice is the most important factor controlling light availability for sea ice algae, but it is predicted by climate models to become more variable and stochastic. Here, we document effects of a sudden, complete loss of the entire snow cover on first-year sea ice at Kangerlussuaq Fjord, West Greenland, due to a natural Föhn wind event that caused a ca. 17 °C air temperature increase over 36 h. We applied Imaging-PAM fluorometry to examine effects of snow cover on algal distribution and photobiology and observed a rapid decrease in algal biomass associated with loss of the skeletal ice crystal layer on the underside of the ice that had supported most of the visible algae. Furthermore, the remaining algae were photobiologically stressed, as seen in a significant decrease in the dark-acclimated fluorescence yield (ΦPSII_max) from 0.55 before snow loss to 0.41 after. However, recovery in the dark suggested that non-photosynthetic quenching was successfully dissipating excess energy in the community and that there was little photodamage. An observed decrease in the photosynthetic efficiency α from 0.22 to 0.16 µmol é m−2 s−1 is therefore likely to be due to photoacclimation and the change in community composition. Centric diatoms and flagellates were the main taxa lost in the snow loss event, whereas the sea ice specialist Nitzschia frigida increased in numbers. These observations are similar to those seen in artificial snow-clearing experiments and consistent with snow clearing being a useful approach for investigating the complex interactions between snow cover, irradiance fluctuations, and ice algal performance.

scholarly journals Sea ice algae chlorophyll a concentrations derived from under-ice spectral radiation profiling platforms

2016 ◽  
Vol 121 (12) ◽  
pp. 8511-8534 ◽  
Author(s):  
Benjamin A. Lange ◽  
Christian Katlein ◽  
Marcel Nicolaus ◽  
Ilka Peeken ◽  
Hauke Flores
Keyword(s):  
Sea Ice ◽  
Chlorophyll A ◽  
Ice Algae ◽  
Spectral Radiation ◽  
Sea Ice Algae

Hydrography and nutrient concentrations in years of contrasting sea ice conditions in the Atlantic inflow region north of Svalbard

2020 ◽  
Author(s):  
Angelika Renner ◽  
Allison Bailey ◽  
Marit Reigstad ◽  
Arild Sundfjord ◽  
Sigrid Øygarden
Keyword(s):  
Sea Ice ◽  
Light Availability ◽  
Late Summer ◽  
Atlantic Water ◽  
Early Summer ◽  
The Arctic ◽  
Nutrient Concentrations ◽  
Boundary Current ◽  
Nutrient Consumption ◽  
Ice Conditions

<p>The shelf break north of Svalbard represents a major gateway for the inflow of nutrient-rich Atlantic Water (AW) to the Arctic Ocean. In this region, AW leaves the surface and subducts below Polar Surface Water (PSW). The supply of nutrients to the euphotic layer therefore varies strongly by season but also interannually, depending on e.g. rates of advection of sea ice and PSW over the AW boundary current. Additionally, the presence of sea ice can limit light availability in spring and early summer. Here, we present results from repeat sampling of hydrography, macronutrients (nitrate/nitrite, phosphate and silicic acid), and chlorophyll a along a transect at 31 E, 81.5 N in the period 2012-2017. Such time series are scarce but invaluable for investigating the range of variability in hydrography and nutrient concentrations. Measurements were done in late summer/early autumn, giving an indication of the nutrient consumption by primary producers over summer. The different years were characterised by very distinct sea ice conditions, both during the productive season and during the field campaigns. This impacted hydrography and primary production and thus nutrient concentrations in the surface and AW layers at the end of summer.</p>

scholarly journals Carbon and nitrogen uptake rates and macromolecular compositions of bottom-ice algae and phytoplankton at Cambridge Bay in Dease Strait, Canada

2020 ◽  
Vol 61 (82) ◽  
pp. 106-116
Author(s):  
Kwanwoo Kim ◽  
Sun-Yong Ha ◽  
Bo Kyung Kim ◽  
C. J. Mundy ◽  
Kathleen M. Gough ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Nutrient Concentrations ◽  
Carbon Uptake ◽  
Ice Algae ◽  
Carbon And Nitrogen ◽  
Uptake Rates ◽  
Marine System ◽  
Landfast Sea Ice

AbstractOur understanding of ice algal responses to the recent changes in Arctic sea ice is impeded by limited field observations. In the present study, environmental characteristics of the landfast sea-ice zone as well as primary production and macromolecular composition of ice algae and phytoplankton were studied in the Kitikmeot Sea near Cambridge Bay in spring 2017. Averaged total chlorophyll-a (Chl-a) concentration was within the lower range reported previously for the same region, while daily carbon uptake rates of bottom-ice algae were significantly lower in this study than previously reported for the Arctic. Based on various indicators, the region's low nutrient concentrations appear to limit carbon uptake rates and associated accumulation of bottom-ice algal biomass. Furthermore, the lipids-dominant biochemical composition of bottom-ice algae suggests strong nutrient limitation relative to the distinctly different carbohydrates-dominant composition of phytoplankton. Together, the results confirm strong nitrate limitation of the local marine system.

Effects of increased irradiance on biomass, photobiology, nutritional quality, and pigment composition of Arctic sea ice algae

2020 ◽  
Vol 648 ◽  
pp. 95-110 ◽  
Author(s):  
LC Lund-Hansen ◽  
I Hawes ◽  
K Hancke ◽  
N Salmansen ◽  
JR Nielsen ◽  
...  
Keyword(s):  
Sea Ice ◽  
Primary Production ◽  
Snow Cover ◽  
Nutritional Quality ◽  
Light Availability ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ice Algae ◽  
Sea Ice Algae ◽  
Arctic Sea

Ice algae are key contributors to primary production and carbon fixation in the Arctic, and light availability is assumed to limit their growth and productivity. We investigated photo-physiological responses in sea ice algae to increased irradiance during a spring bloom in West Greenland. During a 14 d field experiment, light transmittance through sea ice was manipulated to provide 3 under-ice irradiance regimes: low (0.04), medium (0.08), and high (0.16) transmittances. Chlorophyll a decreased with elevated light availability relative to the control. Maximum dark-adapted photosynthetic efficiency (ΦPSII_max) showed an initially healthy and productive ice algae community (ΦPSII_max > 0.6), with ΦPSII_max decreasing markedly under high-light treatments. This was accompanied by a decrease in the light utilization coefficient (α) and photosynthetic capacity (maximum relative electron transfer rate), and a decrease in the ratio of mono- to polyunsaturated fatty acids. This was partly explained by a corresponding increase of photoprotective pigments (diadinoxanthin and diatoxanthin), and a development of mycosporine-like amino acids as identified from a distinctive spectral absorption peak at 360 nm. After 14 d, in situ fluorescence imaging revealed significant differences in ΦPSII_max between treatments of dark-adapted cells (i.e. those sampled before sunrise and after sunset), during diel cycles, with clear chronic photoinhibition in high and medium treatments. Data demonstrate the high sensitivity of spring-blooming Arctic sea ice algae to elevated irradiance caused by loss of snow cover. The predicted loss of snow cover on landfast ice will negatively impact ice algae, their potential primary production, and nutritional quality for higher trophic levels.

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