Physical Control of Phytoplankton Production under Sea Ice (Manitounuk Sound, Hudson Bay)

1981 ◽  
Vol 38 (11) ◽  
pp. 1385-1392 ◽  
Author(s):  
L. Legendre ◽  
R. G. Ingram ◽  
M. Poulin
Keyword(s):  
Surface Water ◽  
Sea Ice ◽  
Water Column ◽  
Phytoplankton Bloom ◽  
Phytoplankton Production ◽  
Hudson Bay ◽  
Ice Algae ◽  
Phytoplankton Blooms ◽  
Low Salinity ◽  
Light Utilization

In polar and subpolar seas, there are numerous accounts of phytoplankton blooms in the upper water column under the ice. Various mechanisms have been invoked to explain these blooms: the seeding of the underlying surface water by algal cells (epontic flora) released from the melting ice, the optimization of light utilization by the cells, and the stabilization of the upper water column by the low-salinity melting water. From studies conducted in Manitounuk Sound (Hudson Bay), it is proposed that phytoplankton blooms under the ice probably result from the simultaneous deepening of both the photic layer (seasonal light increase) and the stratified layer (low-salinity melting water). In ice-covered seas, the release of ice algae superimposes itself on the phytoplankton bloom, resulting in the observed algal increase under melting ice.Key words: phytoplankton, under-ice blooms, ice flora, stability, nutrients, Hudson Bay

scholarly journals Environmental factors influencing the seasonal dynamics of spring algal blooms in and beneath sea ice in western Baffin Bay

Elem Sci Anth ◽  
2019 ◽  
Vol 7 ◽  
Author(s):  
L. Oziel ◽  
P. Massicotte ◽  
A. Randelhoff ◽  
J. Ferland ◽  
A. Vladoiu ◽  
...  
Keyword(s):  
Sea Ice ◽  
Water Column ◽  
Seasonal Dynamics ◽  
Phytoplankton Bloom ◽  
Arctic Sea Ice ◽  
Series Data ◽  
Western Coast ◽  
Snow Melt ◽  
Phytoplankton Blooms ◽  
Baffin Bay

Arctic sea ice is experiencing a shorter growth season and an earlier ice melt onset. The significance of spring microalgal blooms taking place prior to sea ice breakup is the subject of ongoing scientific debate. During the Green Edge project, unique time-series data were collected during two field campaigns held in spring 2015 and 2016, which documented for the first time the concomitant temporal evolution of the sea ice algal and phytoplankton blooms in and beneath the landfast sea ice in western Baffin Bay. Sea ice algal and phytoplankton blooms were negatively correlated and respectively reached 26 (6) and 152 (182) mg of chlorophyll a per m2 in 2015 (2016). Here, we describe and compare the seasonal evolutions of a wide variety of physical forcings, particularly key components of the atmosphere–snow–ice–ocean system, that influenced microalgal growth during both years. Ice algal growth was observed under low-light conditions before the snow melt period and was much higher in 2015 due to less snowfall. By increasing light availability and water column stratification, the snow melt onset marked the initiation of the phytoplankton bloom and, concomitantly, the termination of the ice algal bloom. This study therefore underlines the major role of snow on the seasonal dynamics of microalgae in western Baffin Bay. The under-ice water column was dominated by Arctic Waters. Just before the sea ice broke up, phytoplankton had consumed most of the nutrients in the surface layer. A subsurface chlorophyll maximum appeared and deepened, favored by spring tide-induced mixing, reaching the best compromise between light and nutrient availability. This deepening evidenced the importance of upper ocean tidal dynamics for shaping vertical development of the under-ice phytoplankton bloom, a major biological event along the western coast of Baffin Bay, which reached similar magnitude to the offshore ice-edge bloom.

scholarly journals Implications of sea-ice biogeochemistry for oceanic production and emissions of dimethyl sulfide in the Arctic

2017 ◽  
Vol 14 (12) ◽  
pp. 3129-3155 ◽  
Author(s):  
Hakase Hayashida ◽  
Nadja Steiner ◽  
Adam Monahan ◽  
Virginie Galindo ◽  
Martine Lizotte ◽  
...  
Keyword(s):  
Sea Ice ◽  
Water Column ◽  
Dimethyl Sulfide ◽  
Phytoplankton Bloom ◽  
Model Simulation ◽  
Field Measurements ◽  
Sulfur Cycle ◽  
The Arctic ◽  
Model Parameters ◽  
Ocean Ecosystem

Abstract. Sea ice represents an additional oceanic source of the climatically active gas dimethyl sulfide (DMS) for the Arctic atmosphere. To what extent this source contributes to the dynamics of summertime Arctic clouds is, however, not known due to scarcity of field measurements. In this study, we developed a coupled sea ice–ocean ecosystem–sulfur cycle model to investigate the potential impact of bottom-ice DMS and its precursor dimethylsulfoniopropionate (DMSP) on the oceanic production and emissions of DMS in the Arctic. The results of the 1-D model simulation were compared with field data collected during May and June of 2010 in Resolute Passage. Our results reproduced the accumulation of DMS and DMSP in the bottom ice during the development of an ice algal bloom. The release of these sulfur species took place predominantly during the earlier phase of the melt period, resulting in an increase of DMS and DMSP in the underlying water column prior to the onset of an under-ice phytoplankton bloom. Production and removal rates of processes considered in the model are analyzed to identify the processes dominating the budgets of DMS and DMSP both in the bottom ice and the underlying water column. When openings in the ice were taken into account, the simulated sea–air DMS flux during the melt period was dominated by episodic spikes of up to 8.1 µmol m−2 d−1. Further model simulations were conducted to assess the effects of the incorporation of sea-ice biogeochemistry on DMS production and emissions, as well as the sensitivity of our results to changes of uncertain model parameters of the sea-ice sulfur cycle. The results highlight the importance of taking into account both the sea-ice sulfur cycle and ecosystem in the flux estimates of oceanic DMS near the ice margins and identify key uncertainties in processes and rates that should be better constrained by new observations.

scholarly journals Photosynthetic production in the Central Arctic during the record sea-ice minimum in 2012

2015 ◽  
Vol 12 (3) ◽  
pp. 2897-2945 ◽  
Author(s):  
M. Fernández-Méndez ◽  
C. Katlein ◽  
B. Rabe ◽  
M. Nicolaus ◽  
I. Peeken ◽  
...  
Keyword(s):  
Sea Ice ◽  
Primary Production ◽  
Arctic Ocean ◽  
Water Column ◽  
Primary Productivity ◽  
Ice Cover ◽  
Annual Production ◽  
Ice Algae ◽  
Central Arctic Ocean ◽  
Eurasian Basin

Abstract. The ice-covered Central Arctic Ocean is characterized by low primary productivity due to light and nutrient limitations. The recent reduction in ice cover has the potential to substantially increase phytoplankton primary production, but little is yet known about the fate of the ice-associated primary production and of the nutrient supply with increasing warming. This study presents results from the Central Arctic Ocean collected during summer 2012, when sea-ice reached a minimum extent since the onset of satellite observations. Net primary productivity (NPP) was measured in the water column, sea ice and melt ponds by 14CO2 uptake at different irradiances. Photosynthesis vs. irradiance (PI) curves were established in laboratory experiments and used to upscale measured NPP to the deep Eurasian Basin (north of 78° N) using the irradiance-based Central Arctic Ocean Primary Productivity (CAOPP) model. In addition, new annual production was calculated from the seasonal nutrient drawdown in the mixed layer since last winter. Results show that ice algae can contribute up to 60% to primary production in the Central Arctic at the end of the season. The ice-covered water column has lower NPP rates than open water due to light limitation. As indicated by the nutrient ratios in the euphotic zone, nitrate was limiting primary production in the deep Eurasian Basin close to the Laptev Sea area, while silicate was the main limiting nutrient at the ice margin near the Atlantic inflow. Although sea-ice cover was substantially reduced in 2012, total annual new production in the Eurasian Basin was 17 ± 7 Tg C yr-1, which is within the range of estimates of previous years. However, when adding the contribution by sub-ice algae, the annual production for the deep Eurasian Basin (north of 78° N) could double previous estimates for that area with a surplus of 16 Tg C yr-1. Our data suggest that sub-ice algae are an important component of the ice-covered Central Arctic productivity. It remains an important question if their contribution to productivity is on the rise with thinning ice, or if it will decline due to overall sea-ice retreat and be replaced by phytoplankton.

scholarly journals Temporal evolution of IP25 and other highly branched isoprenoid lipids in sea ice and the underlying water column during an Arctic melting season

Elem Sci Anth ◽  
2019 ◽  
Vol 7 ◽  
Author(s):  
Rémi Amiraux ◽  
Lukas Smik ◽  
Denizcan Köseoğlu ◽  
Jean-François Rontani ◽  
Virginie Galindo ◽  
...  
Keyword(s):  
Sea Ice ◽  
Water Column ◽  
Spring Bloom ◽  
Phytoplankton Bloom ◽  
Change Point Analysis ◽  
The Arctic ◽  
Distribution Data ◽  
Ice Melt ◽  
Point Analysis ◽  
The Impact

In recent years, certain mono- and di-unsaturated highly branched isoprenoid (HBI) alkene biomarkers (i.e., IP25 and HBI IIa) have emerged as useful proxies for sea ice in the Arctic and Antarctic, respectively. Despite the relatively large number of sea ice reconstructions based on IP25 and HBI IIa, considerably fewer studies have addressed HBI variability in sea ice or in the underlying water column during a spring bloom and ice melt season. In this study, we quantified IP25 and various other HBIs at high temporal and vertical resolution in sea ice and the underlying water column (suspended and sinking particulate organic matter) during a spring bloom/ice melt event in Baffin Bay (Canadian Arctic) as part of the Green Edge project. The IP25 data are largely consistent with those reported from some previous studies, but also highlight: (i) the short-term variability in its production in sea ice; (ii) the release of ice algae with high sinking rates following a switch in sea ice conditions from hyper- to hyposaline within the study period; and (iii) the occurrence of an under-ice phytoplankton bloom. Outcomes from change-point analysis conducted on chlorophyll a and IP25, together with estimates of the percentage of ice algal organic carbon in the water column, also support some previous investigations. The co-occurrence of other di- and tri-unsaturated HBIs (including the pelagic biomarker HBI III) in sea ice are likely to have originated from the diatom Berkeleya rutilans and/or the Pleurosigma and Rhizosolenia genera, residing either within the sea ice matrix or on its underside. Although a possible sea ice source for HBIs such as HBI III may also impact the use of such HBIs as pelagic counterparts to IP25 in the phytoplankton marker-IP25 index, we suggest that the impact is likely to be small based on HBI distribution data.

Southern ocean–sea-ice interaction: implications for climate and modelling

1990 ◽  
Vol 81 (4) ◽  
pp. 397-405 ◽  
Author(s):  
Douglas G. Martinson
Keyword(s):  
Surface Water ◽  
Sea Ice ◽  
Water Column ◽  
Deep Water ◽  
Stable Region ◽  
Deep Water Formation ◽  
Sea Ice Thickness ◽  
Water Column Stability ◽  
Water Formation ◽  
Ocean Region

ABSTRACTThe ocean/sea-ice interaction of the Antarctic open ocean region is described through a one-dimensional model. The model includes processes responsible for maintaining stability in this marginally stable region and reveals the importance of the various processes controlling deep water formation/ventilation and sea-ice thickness and their sensitivity to climate change. This information is used to estimate changes, as they impact water column stability, induced by glacial conditions. Increased stability is conducive to greater ice cover and less deep water formation/ventilation; decreased stability conducive to the opposite.Sensitivity studies show that the system is destabilised given: (1) shallowing of the pycnocline (induced by increased gyre vigor); (2) decrease in the ratio of heat to salt through the pycnocline (induced by introducing a colder and/or saltier deep water or by increasing the salinity of the surface water); (3) decreased pycnocline strength (induced by a fresher deep water or saltier surface water) and (4) increased atmospheric heat loss. Most of the assumed glacial conditions drive the system toward destabilisation, but the critical effect of changes in NADW characteristics depends strongly on the temperature and salinity of the replacement water. The importance of this deep water influence is evident today—as little as 3Wm−2 in the upper ocean heat balance or an additional 15 cm of ice growth is sufficient to overturn the water column in some regions.

scholarly journals Meteoric water contribution to sea ice formation and its control of the surface water carbonate cycle on the Wandel Sea shelf, northeastern Greenland

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Nicolas-Xavier Geilfus ◽  
Kathleen Munson ◽  
Marcos Lemes ◽  
Feiyue Wang ◽  
Jean-Louis Tison ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Surface Water ◽  
Sea Ice ◽  
Water Column ◽  
Inorganic Carbon ◽  
Meteoric Water ◽  
Ice Cover ◽  
Total Alkalinity ◽  
Carbonate Minerals ◽  
Glacial Meltwater

An influx of glacial meltwater has the ability to alter the properties of marine surface waters and their ability to exchange CO2 through changes to water column stratification and the inorganic carbon system. Here, we report how inputs of meteoric water affect the physical and biogeochemical properties of both the water column and the sea ice cover on the Wandel Sea shelf, northeastern Greenland, during spring 2015. The observed depleted δ18O–H2O in the water column, with surface water values as low as –16.3 ‰, suggests a strong input of meteoric water (i.e., water derived from atmospheric precipitation). Depleted δ18O–H2O observed within sea ice (from –21.5 to –8.0 ‰) reflects its formation from surface water that was already depleted isotopically. In addition, a thick snow cover, as present during the study, promotes the formation of snow ice as well as insulates the ice cover. Within sea ice, the resulting relatively warm temperature and low salinity impedes ikaite formation. However, measurements of total dissolved inorganic carbon and total alkalinity indicate that, in both sea ice and the water column, the dissolution of calcium carbonate was the main process affecting the carbonate system. This finding suggests that inputs of glacial meltwater deliver glacier-derived carbonate minerals to the ocean which become incorporated within the ice structure, increasing calcium carbonate dissolution in the water column in the absence of ikaite precipitation within the sea ice. If widespread in glacial-fed waters, bedrock carbonate minerals could increase CO2 sequestration in glacial catchments despite the weakening of the sea ice carbon pump.

scholarly journals Processes controlling aggregate formation and distribution during the Arctic phytoplankton spring bloom in Baffin Bay

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Jordan Toullec ◽  
Brivaëla Moriceau ◽  
Dorothée Vincent ◽  
Lionel Guidi ◽  
Augustin Lafond ◽  
...  
Keyword(s):  
Sea Ice ◽  
Spring Bloom ◽  
Phytoplankton Bloom ◽  
Light Availability ◽  
Open Water ◽  
The Arctic ◽  
Phytoplankton Production ◽  
Baffin Bay ◽  
Migration Pathway ◽  
Phytoplankton Cells

In the last decades, the Arctic Ocean has been affected by climate change, leading to alterations in the sea ice cover that influence the phytoplankton spring bloom, its associated food web, and therefore carbon sequestration. During the Green Edge 2016 expedition in the central Baffin Bay, the phytoplankton spring bloom and its development around the ice edge was followed along 7 transects from open water to the ice-pack interior. Here, we studied some of the processes driving phytoplankton aggregation, using aggregate and copepod distribution profiles obtained with an underwater vision profiler deployed at several stations along the transects. Our results revealed a sequential pattern during sea ice retreat in phytoplankton production and in aggregate production and distribution. First, under sea ice, phytoplankton started to grow, but aggregates were not formed. Second, after sea ice melting, phytoplankton (diatoms and Phaeocystis spp. as the dominant groups) benefited from the light availability and stratified environment to bloom, and aggregation began coincident with nutrient depletion at the surface. Third, maxima of phytoplankton aggregates deepened in the water column and phytoplankton cells at the surface began to degrade. At most stations, silicate limitation began first, triggering aggregation of the phytoplankton cells; nitrate limitation came later. Copepods followed aggregates at the end of the phytoplankton bloom, possibly because aggregates provided higher quality food than senescing phytoplankton cells at the surface. These observations suggest that aggregation is involved in 2 export pathways constituting the biological pump: the gravitational pathway through the sinking of aggregates and fecal pellets and the migration pathway when zooplankton follow aggregates during food foraging.

scholarly journals Phenology and Environmental Control of Phytoplankton Blooms in the Kong Håkon VII Hav in the Southern Ocean

2021 ◽  
Vol 8 ◽  
Author(s):  
Hanna M. Kauko ◽  
Tore Hattermann ◽  
Thomas Ryan-Keogh ◽  
Asmita Singh ◽  
Laura de Steur ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Environmental Changes ◽  
Environmental Control ◽  
Phytoplankton Bloom ◽  
Mixed Layer Depth ◽  
Marine Ecosystem ◽  
Light Availability ◽  
Phytoplankton Blooms ◽  
Atlantic Sector

Knowing the magnitude and timing of pelagic primary production is important for ecosystem and carbon sequestration studies, in addition to providing basic understanding of phytoplankton functioning. In this study we use data from an ecosystem cruise to Kong Håkon VII Hav, in the Atlantic sector of the Southern Ocean, in March 2019 and more than two decades of satellite-derived ocean color to study phytoplankton bloom phenology. During the cruise we observed phytoplankton blooms in different bloom phases. By correlating bloom phenology indices (i.e., bloom initiation and end) based on satellite remote sensing to the timing of changes in environmental conditions (i.e., sea ice, light, and mixed layer depth) we studied the environmental factors that seemingly drive phytoplankton blooms in the area. Our results show that blooms mainly take place in January and February, consistent with previous studies that include the area. Sea ice retreat controls the bloom initiation in particular along the coast and the western part of the study area, whereas bloom end is not primarily connected to sea ice advance. Light availability in general is not appearing to control the bloom termination, neither is nutrient availability based on the autumn cruise where we observed non-depleted macronutrient reservoirs in the surface. Instead, we surmise that zooplankton grazing plays a potentially large role to end the bloom, and thus controls its duration. The spatial correlation of the highest bloom magnitude with marked topographic features indicate that the interaction of ocean currents with sea floor topography enhances primary productivity in this area, probably by natural fertilization. Based on the bloom timing and magnitude patterns, we identified five different bloom regimes in the area. A more detailed understanding of the region will help to highlight areas with the highest relevance for the carbon cycle, the marine ecosystem and spatial management. With this gained understanding of bloom phenology, it will also be possible to study potential shifts in bloom timing and associated trophic mismatch caused by environmental changes.

scholarly journals Photosynthetic production in the central Arctic Ocean during the record sea-ice minimum in 2012

2015 ◽  
Vol 12 (11) ◽  
pp. 3525-3549 ◽  
Author(s):  
M. Fernández-Méndez ◽  
C. Katlein ◽  
B. Rabe ◽  
M. Nicolaus ◽  
I. Peeken ◽  
...  
Keyword(s):  
Sea Ice ◽  
Primary Production ◽  
Arctic Ocean ◽  
Water Column ◽  
Primary Productivity ◽  
Ice Cover ◽  
Annual Production ◽  
Ice Algae ◽  
Central Arctic Ocean ◽  
Eurasian Basin

Abstract. The ice-covered central Arctic Ocean is characterized by low primary productivity due to light and nutrient limitations. The recent reduction in ice cover has the potential to substantially increase phytoplankton primary production, but little is yet known about the fate of the ice-associated primary production and of the nutrient supply with increasing warming. This study presents results from the central Arctic Ocean collected during summer 2012, when sea-ice extent reached its lowest ever recorded since the onset of satellite observations. Net primary productivity (NPP) was measured in the water column, sea ice and melt ponds by 14CO2 uptake at different irradiances. Photosynthesis vs. irradiance (PI) curves were established in laboratory experiments and used to upscale measured NPP to the deep Eurasian Basin (north of 78° N) using the irradiance-based Central Arctic Ocean Primary Productivity (CAOPP) model. In addition, new annual production has been calculated from the seasonal nutrient drawdown in the mixed layer since last winter. Results show that ice algae can contribute up to 60% to primary production in the central Arctic Ocean at the end of the productive season (August–September). The ice-covered water column has lower NPP rates than open water due to light limitation in late summer. As indicated by the nutrient ratios in the euphotic zone, nitrate was limiting primary production in the deep Eurasian Basin close to the Laptev Sea area, while silicate was the main limiting nutrient at the ice margin near the Atlantic inflow. Although sea-ice cover was substantially reduced in 2012, total annual new production in the Eurasian Basin was 17 ± 7 Tg C yr−1, which is within the range of estimates of previous years. However, when adding the contribution by sub-ice algae, the annual production for the deep Eurasian Basin (north of 78° N) could double previous estimates for that area with a surplus of 16 Tg C yr−1. Our data suggest that sub-ice algae are an important component of the productivity in the ice-covered Eurasian Basin of the central Arctic Ocean. It remains an important question whether their contribution to productivity is on the rise with thinning ice, or whether it will decline due to overall sea-ice retreat and be replaced by phytoplankton.

scholarly journals Late and Postglacial Paleoenvironments of the Gulf of St. Lawrence: Marine and Terrestrial Palynological Evidence

2007 ◽  
Vol 47 (2) ◽  
pp. 167-180 ◽  
Author(s):  
Anne de Vernal ◽  
Joël Guiot ◽  
Jean-Louis Turon
Keyword(s):  
Surface Water ◽  
Sea Ice ◽  
Sea Surface ◽  
Early Holocene ◽  
Laurentide Ice Sheet ◽  
Gulf Region ◽  
Low Salinity ◽  
Cooling Phase ◽  
Summer Temperatures ◽  
Younger Dryas Event

ABSTRACT Cored sediments from Anticosti and Esquiman channels and from Cabot Strait have been analyzed for their palynological content, which includes pollen and spores and dinoflagellate cysts. The dinoflagellate cyst assemblages led to the establishment of a regional ecostratigraphy and to quantitative reconstruction of changes in sea-surface conditions using transfer function (best analogue method). Prior to about 10,000 BP, assemblages dominated by Brigantedinium are associated with relatively cold (4-100C in August) surface water and extensive seasonal sea-ice cover (up to 8 months/yr.); in Cabot Strait low salinity conditions (25-27%o) were recorded from about 11,800 to 10,000 BP as the result of outflow of meltwater discharge from the Laurentide Ice Sheet. Between ca. 11,000 and 10,500 BP a cooling phase in surface water probably corresponds to the Younger Dryas event. At about 10,000 BP, a sharp transition marked by the occurrence of abundant Gonyaulacales, corresponds to the establishment of conditions similar to the present with summer temperatures up to 160C, salinity of -31 %o and a seasonal extent of sea-ice of about 2 months/yr. During the Holocene, slight fluctuations of sea-surface temperature are reconstructed, and a thermal optimum is recorded at about 6000 BP. The pollen and spore assemblages led to direct correlations with the onshore palynostratigraphy. In the northern Gulf region, Picea migration apparently rapidly followed the early Holocene surface water warming although the development of closed coniferous forests occurred much later. In the southern part of the Gulf, the Picea forest expansion coincides with the early Holocene increase of temperature, and the significant occurrence of Tsuga followed the middle Holocene thermal optimum as recorded in sea-surface water.

Sign in / Sign up

Export Citation Format

Share Document