Impacts on phytoplankton dynamics by free-drifting icebergs in the NW Weddell Sea

Vernet, María; Sines, Karie; Chakos, D.; Cefarelli, Adrián Oscar; Ekern, Lindsey

doi:10.1016/j.dsr2.2010.11.022

Cited by 52 publications

(47 citation statements)

References 74 publications

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“…The continued break up of ice shelves will also lead to an increase in icebergs over the CZ. Melting icebergs have been found to provide a significant amount of iron and nutrients to surface waters, leading to increased phytoplankton productivity (Lin et al, 2011;Vernet et al, 2011;Duprat et al, 2016). Increased iceberg numbers will also contribute to increased productivity throughout the SSIZ and POOZ as they are propelled by ocean currents around Antarctica (see above).…”

Section: West Antarcticamentioning

confidence: 99%

“…Climate warming and the breakup of Antarctic ice shelves (Scambos et al, 2000) could increase the number of icebergs in the POOZ (see CZ below). Melting icebergs enrich the surrounding water with iron, enhancing phytoplankton growth and productivity Lin et al, 2011;Shaw et al, 2011;Vernet et al, 2011Vernet et al, , 2012, and increasing export of carbon from surface waters (Smith et al, 2011). This heightened productivity also attracts large grazing populations that increase food availability to higher trophic levels and facilitates the sequestration of carbon to the deep ocean through fecal pellet production .…”

Section: Permanently Open Ocean Zonementioning

confidence: 99%

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Southern Ocean Phytoplankton in a Changing Climate

2017

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Phytoplankton are the base of the Antarctic food web, sustain the wealth and diversity of life for which Antarctica is renowned, and play a critical role in biogeochemical cycles that mediate global climate. Over the vast expanse of the Southern Ocean (SO), the climate is variously predicted to experience increased warming, strengthening wind, acidification, shallowing mixed layer depths, increased light (and UV), changes in upwelling and nutrient replenishment, declining sea ice, reduced salinity, and the southward migration of ocean fronts. These changes are expected to alter the structure and function of phytoplankton communities in the SO. The diverse environments contained within the vast expanse of the SO will be impacted differently by climate change; causing the identity and the magnitude of environmental factors driving biotic change to vary within and among bioregions. Predicting the net effect of multiple climate-induced stressors over a range of environments is complex. Yet understanding the response of SO phytoplankton to climate change is vital if we are to predict the future state/s of the ecosystem, estimate the impacts on fisheries and endangered species, and accurately predict the effects of physical and biotic change in the SO on global climate. This review looks at the major environmental factors that define the structure and function of phytoplankton communities in the SO, examines the forecast changes in the SO environment, predicts the likely effect of these changes on phytoplankton, and considers the ramifications for trophodynamics and feedbacks to global climate change. Predictions strongly suggest that all regions of the SO will experience changes in phytoplankton productivity and community composition with climate change. The nature, and even the sign, of these changes varies within and among regions and will depend upon the magnitude and sequence in which these environmental changes are imposed. It is likely that predicted changes to phytoplankton communities will affect SO biogeochemistry, carbon export, and nutrition for higher trophic levels.

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Section: West Antarcticamentioning

confidence: 99%

Section: Permanently Open Ocean Zonementioning

confidence: 99%

Southern Ocean Phytoplankton in a Changing Climate

2017

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“…The winds induce water turbulence and resuspension of sediments in shallow parts of the bay. The input of fresh water from melting glaciers bearing mineral suspensions causes an increase in turbidity, decrease in light intensity and decrease in surface salinity (Lipski 1987;Schwarz and Schodlock 2009;Vernet et al 2011). These phenomena contribute to the complex hydrology of the area, particularly near retreating glaciers and close to freshwater streams (Dierssen et al 2002).…”

Section: Study Areamentioning

confidence: 99%

Temporal and spatial variation of phytoplankton in Admiralty Bay, South Shetlands: the dynamics of summer blooms shown by pigment and light microscopy analysis

2015

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We conducted an integrated study of phytoplankton taxonomic composition, biomass and physicochemical properties of the water in Admiralty Bay, South Shetlands. The aim of the study was to provide detailed information on phytoplankton composition and diversity related to relevant environmental conditions. High-performance liquid chromatography pigment analysis and microscopy were performed in the summers of 2007 and 2009-2010. Results for 2007 showed a typical high-nutrient, low-chlorophyll system. Total carbon biomass and cell numbers were dominated by nanoflagellates, while diatoms made up 1.2-4.5 % of the total algal numbers and contributed a maximum of 23.4 % to the total cell carbon. A small algal bloom occurred in the center of the bay, with chlorophyll a values of *1.0 lg l -1 . The prevalent pigment was 19 0 -hexanoyloxyfucoxanthin, characteristic of the Prymnesiophyceae. In January 2010, the values of chlorophyll a (8-24 lg l -1 ) and cell carbon (150 lg l -1 ) were the highest ever recorded for Admiralty Bay. In general the algal populations were dominated numerically by nanoflagellates, but a bloom of diatoms (maximum 30 % of total cells and 50 % of total cell carbon) was observed. Diatoms were dominated by those of micro-size: Thalassiosira ritscheri and T. antarctica. The dominant pigment was fucoxanthin, mainly found in diatoms. The diatom bloom could be related to the southeast wind direction, stable water column conditions and an inflow of diatom-rich waters from the Bransfield Strait, while the input of high-turbidity, low-salinity water from melting glaciers and strong katabatic northwest winds could favor nanoflagellates.

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“…In the fall, phytoplankton biomass is variable, with chl a concentrations anywhere from 0.1 to 2 mg m −3 within the surface mixed layer (Vernet et al 2011).…”

Section: Resale or Republication Not Permitted Without Written Consenmentioning

confidence: 99%

Primary production throughout austral fall, during a time of decreasing daylength in the western Antarctic Peninsula

Vernet¹,

Kozlowski²,

Yarmey³

et al. 2012

Mar. Ecol. Prog. Ser.

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Antarctic phytoplankton is characterized by a pronounced seasonality in abundance, driven mainly by changes in sunlight. We combined measurements and modeling to describe the influence of changing daylength on fall and winter phytoplankton production in coastal waters of the western Antarctic Peninsula (wAP) in 2001 and 2002. The model was parameterized with field observations from the Palmer Long-Term Ecological program in the wAP during summer and early fall and from the Southern Ocean Global Ecosystems Dynamics program fall and winter cruises to Marguerite Bay and shelf waters. Shorter daylength and a deepening of the mixed layer account for most of the decrease in primary production during March, April, and May. At this time, biomass decreases by an order of magnitude and remains low and constant until the end of August. An additional loss rate was added to the primary production model to fit output to observations. This loss rate, estimated at ~0.1 to 0.15 d −1 , is due to physical, chemical, and biological processes such as scavenging by sea ice, zooplankton grazing, cell lysis, and cell sedimentation, which are expected to be high at this time of year. Growth and loss rates of phytoplankton populations are similar on 1 March, with growth decreasing rapidly over time while the loss rates remain constant. By the beginning of winter (1 June), growth is low, with minimum rates in July and increasing towards September. During a period of diminishing food supply, preliminary estimates of grazing indicate that fall biomass could support existing macrozooplankton populations, but the timing and concentration of food supply is variable and expected to affect health of zooplankton as they enter the winter.KEY WORDS: Phytoplankton · Primary production · Antarctica · Bloom demise · Fall · Winter · Growth rates · Loss rates Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 452: [45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61] 2012 summer of 1 to 3 mg chlorophyll a (chl a) m −3 with peaks or blooms up to 30 mg m −3 (Smith et al. 1998) decreases to a low of < 0.2 mg m −3 in the winter , Fritsen et al. 2008, Meyer et al. 2009). In the fall, phytoplankton biomass is variable, with chl a concentrations anywhere from 0.1 to 2 mg m −3 within the surface mixed layer (Vernet et al. 2011).Our knowledge of fall and winter phytoplankton dynamics in the Southern Ocean is limited by the difficulty of sampling underneath the ice and the lack of ocean color remote sensing images from April to October due to low sun angle (Marrari et al. 2008). This lack of information precludes understanding variability due to latitude and interannual changes in the water column. Scarce supply of food during winter combined with low starvation tolerance of some zooplankton, e.g. larval krill, might necessitate their use of an alternative food source (Walsh et al. 2001). Several investigators (Daly 1990, Smetacek et al. 1990, Quetin & Ross 1991 have suggested that sea i...

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Impacts on phytoplankton dynamics by free-drifting icebergs in the NW Weddell Sea

Cited by 52 publications

References 74 publications

Southern Ocean Phytoplankton in a Changing Climate

Southern Ocean Phytoplankton in a Changing Climate

Temporal and spatial variation of phytoplankton in Admiralty Bay, South Shetlands: the dynamics of summer blooms shown by pigment and light microscopy analysis

Primary production throughout austral fall, during a time of decreasing daylength in the western Antarctic Peninsula

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