Modeling of the Influence of Sea Ice Cycle and Langmuir Circulation on the Upper Ocean Mixed Layer Depth and Freshwater Distribution at the West Antarctic Peninsula

Schultz, Cristina; Doney, Scott C.; Zhang, Weifeng G.; Regan, Heather; Holland, Paul R.; Meredith, Michael P.; Stammerjohn, Sharon

doi:10.1002/essoar.10502066.1

Cited by 2 publications

(7 citation statements)

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“…The measured pH values were calibrated against the pH values calculated from underway pCO 2 data collected on board the ship in the vicinity of the mooring location and salinity-derived TA (Shadwick et al, 2021). Salinity data for the 2018 deployment was incomplete (stopped in May 2018), and therefore was filled with results from a 3-D regional ocean model (Saenz & Arrigo, 2014;Schultz, 2019;Schultz et al, 2020).…”

Section: Data Acquisitionmentioning

confidence: 99%

“…The salinity-normalized DIC gradient was obtained from a separate, 3-D modeled seasonal climatology (Schultz, 2019;Schultz et al, 2020). For each mixed layer DIC model time step, dDIC/dz below the corresponding MLD was calculated using the climatological DIC profile from the 3-D model outputs.…”

Section: Mixed Layer Carbon Mass Balance Modelmentioning

confidence: 99%

“…The model simulated vertical DIC gradients (dDIC/dz, Figure 4) across the base of the mixed layer (Schultz 2019;Schultz et al, 2020) were relatively small (between 0.5 and 2 mmol m −4 ), with higher values in the summer, when MLD was shallow, and lower values in winter. Although the same climatological model outputs were used for both years (deployments), the magnitudes of dDIC/dz for the 2017 and 2018 deployments were different due to the difference in the observed MLD, reflecting variations in the vertical profile of dDIC/dz.…”

Section: Computed Variablesmentioning

confidence: 99%

“…Figure 4. Annual cycles of salinity-normalized DIC gradients (dDIC/dz, mmol m −4 ) across the base of the mixed layer.The gradient was a seasonal climatology calculated from a 1991-2014 model result(Schultz, 2019;Schultz et al, 2020). The gray dots and blue crosses indicate the original data, and the smoothed (30-day running mean) are presented in gray and blue lines.…”

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confidence: 99%

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Annual Mixed Layer Carbon Budget for the West Antarctic Peninsula Continental Shelf: Insights From Year‐Round Mooring Measurements

et al. 2021

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The Western Antarctic Peninsula (WAP, Figure 1) is a highly productive ocean coastal/shelf region with an estimated annual primary production of over 1.0 Tg C yr −1 (Moreau et al., 2015), which supports ample phytoplankton carbon stocks at the base of the polar marine ecosystem (Ducklow et al., 2013). The WAP region is also generally considered as a strong seasonal sink for atmospheric CO 2 (Carrillo et al., 2004;Legge et al., 2017), although some studies (e.g., Roobaert et al., 2019) showed that the northern tip of WAP is a net annual CO 2 source to the atmosphere. The WAP marine ecosystem is largely shaped by the unique physical conditions of the polar, seasonally ice-covered coastal region (Ducklow et al., 2013). The Antarctic Circumpolar Current (ACC) flows eastward along the continental slope of the WAP region, transporting a large volume of warm water just below the surface layer (known as Upper Circumpolar Deep Water, UCDW) (Martinson & McKee, 2012;Martinson et al., 2008). The onshore flow of this warm water mass, primarily through subsea canyons and mesoscale eddies, supplies heat, nutrients and dissolved inorganic carbon (DIC) to the WAP continental shelf with important ecological and biogeochemical impacts (Ducklow et al., 2013;Hauri et al., 2015). Freshwater input from sea-ice melting and glacial runoff also have strong

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Section: Data Acquisitionmentioning

confidence: 99%

Section: Mixed Layer Carbon Mass Balance Modelmentioning

confidence: 99%

Section: Computed Variablesmentioning

confidence: 99%

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Annual Mixed Layer Carbon Budget for the West Antarctic Peninsula Continental Shelf: Insights From Year‐Round Mooring Measurements

et al. 2021

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“…Reductions in ice sheets and sea ice and weakened vertical mixing can increase the availability of iron and light in this area, which is expected to impact lower‐trophic‐level biota (Boyd & Brown, 2015; Boyd et al., 2016; Brown et al., 2019). On the other hand, the increase in the exposure duration of the upper pelagic layer to the atmosphere with the increasing sea ice retreat might play a role in reducing light availability or increasing nutrients (e.g., iron) supply into the euphotic depth by inducing intermittent wind‐driven mixing (Schultz et al., 2020).…”

Section: Introductionmentioning

confidence: 99%

Exploring the Roles of Iron and Irradiance in Dynamics of Diatoms and Phaeocystis in the Amundsen Sea Continental Shelf Water

Kwon

Jung

et al. 2021

JGR Oceans

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The Southern Ocean, generally defined as the waters occurring south of 60°S and encircling Antarctica, plays a disproportionate role in control of atmospheric carbon by contributing ∼40% of the total oceanic uptake of anthropogenic carbon dioxide (CO 2) emissions (Frölicher et al., 2015; Khatiwala et al., 2009; Takahashi et al., 2009, 2012). In particular, the Antarctic continental shelf areas show substantial carbon uptake capacity due to efficient biological pump through primary production (Arrigo et al., 2008) during the summertime when sea ice retreat allows solar irradiance penetration into the upper ocean. However, the reason for the low efficiency of carbon export into the deep ocean despite the high productivity in the upper Abstract The Amundsen Sea continental shelf (ACS) water ecosystem is expected to undergo changes since increasing melt rate of glacier and decreasing sea ice extent by global warming would lead to the mitigation of iron and light limitation. We investigated how diatoms and Phaeocystis, two dominant taxa, and primary production in the ACS water would respond to variations in iron and light availabilities by using a 1-D pelagic ecosystem model. In the model, we added sea ice effects that reduce light penetration and optimized model parameters for diatoms and Phaeocystis. The results from our model showed good agreement with 20-year observations of Chl-a as well as the biomass proportion of diatoms and Phaeocystis and nutrient distributions during the growing season. Our model experimental results suggest that the current moderate iron and high light conditions favor the growth of Phaeocystis over diatoms. Moreover, as iron increases, the organic carbon exudation by phytoplankton increases more rapidly than net primary production (NPP), leading to a decline in phytoplankton biomass. On the other hand, irradiance plays a role in controlling NPP in terms of photoinhibition which is reduced by increasing iron. Increases in both iron and irradiance lead to an advance in the timing of the bloom peak (surface Chl-a maximum) due to increases in phytoplankton carbon loss and photoinhibition. Our results imply that the dominance of Phaeocystis can continue and that the carbon uptake capacity of the ACS in the summer seasons might increase given that iron availability will increase with future climate change. Plain Language Summary We firmly believe that this research based on an optimum biogeochemical model developed for the Amundsen Sea continental shelf water is of sufficiently broad interest for the public as well as the scientific community, since it advances the study of phytoplankton ecology and carbon uptake in the Antarctic coastal area. A complex coupled ocean-ecosystem model was developed to investigate dynamics of the two dominant species (diatoms and Phaeocystis) in the ACS water, one of the most rapidly warming regions on Earth with extremely high primary productivity. These two groups are particularly important as they could significantly contribute to the carbon export into the dee...

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Modeling of the Influence of Sea Ice Cycle and Langmuir Circulation on the Upper Ocean Mixed Layer Depth and Freshwater Distribution at the West Antarctic Peninsula

Cited by 2 publications

References 40 publications

Annual Mixed Layer Carbon Budget for the West Antarctic Peninsula Continental Shelf: Insights From Year‐Round Mooring Measurements

Annual Mixed Layer Carbon Budget for the West Antarctic Peninsula Continental Shelf: Insights From Year‐Round Mooring Measurements

Exploring the Roles of Iron and Irradiance in Dynamics of Diatoms and Phaeocystis in the Amundsen Sea Continental Shelf Water

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