Modelling carbon cycling through phytoplankton and microbes in the Scotia—Weddell Sea area during sea ice retreat

1991 ◽  
Vol 35 (1-4) ◽  
pp. 305-324 ◽  
Author(s):  
Christiane Lancelot ◽  
Gilles Billen ◽  
Cornelis Veth ◽  
Sylvie Becquevort ◽  
Sylvie Mathot
Keyword(s):  
Sea Ice ◽  
Carbon Cycling ◽  
Weddell Sea ◽  
Ice Retreat ◽  
Sea Ice Retreat ◽  
Sea Area

scholarly journals On the freshening of the northwestern Weddell Sea continental shelf

Ocean Science ◽  
2011 ◽  
Vol 7 (3) ◽  
pp. 305-316 ◽  
Author(s):  
H. H. Hellmer ◽  
O. Huhn ◽  
D. Gomis ◽  
R. Timmermann
Keyword(s):  
Sea Ice ◽  
Continental Shelf ◽  
Weddell Sea ◽  
Central Basin ◽  
Thermal Front ◽  
Late 20Th Century ◽  
Ice Shelves ◽  
Ice Retreat ◽  
Reduced Salt ◽  
Sea Ice Retreat

Abstract. We analyzed hydrographic data from the northwestern Weddell Sea continental shelf of the three austral winters 1989, 1997, and 2006 and two summers following the last winter cruise. During summer a thermal front exists at ~64° S separating cold southern waters from warm northern waters that have similar characteristics as the deep waters of the central basin of the Bransfield Strait. In winter, the whole continental shelf exhibits southern characteristics with high Neon (Ne) concentrations, indicating a significant input of glacial melt water. The comparison of the winter data from the shallow shelf off the tip of the Antarctic Peninsula, spanning a period of 17 yr, shows a salinity decrease of 0.09 for the whole water column, which has a residence time of <1 yr. We interpret this freshening as being caused by a combination of reduced salt input due to a southward sea ice retreat and higher precipitation during the late 20th century on the western Weddell Sea continental shelf. However, less salinification might also result from a delicate interplay between enhanced salt input due to sea ice formation in coastal areas formerly occupied by Larsen A and B ice shelves and increased Larsen C ice loss.

scholarly journals Moisture transport and Antarctic sea ice: austral spring 2016 event

2018 ◽  
Vol 9 (3) ◽  
pp. 939-954 ◽  
Author(s):  
Monica Ionita ◽  
Patrick Scholz ◽  
Klaus Grosfeld ◽  
Renate Treffeisen
Keyword(s):  
Indian Ocean ◽  
Sea Ice ◽  
Ross Sea ◽  
Weddell Sea ◽  
Antarctic Region ◽  
Austral Spring ◽  
Ice Retreat ◽  
The Indian Ocean ◽  
Sea Ice Retreat ◽  
The Antarctic

Abstract. In austral spring 2016 the Antarctic region experienced anomalous sea ice retreat in all sectors, with sea ice extent in October and November 2016 being the lowest in the Southern Hemisphere over the observational period (1979–present). The extreme sea ice retreat was accompanied by widespread warming along the coastal areas as well as in the interior of the Antarctic continent. This exceptional event occurred along with a strong negative phase of the Southern Annular Mode (SAM) and the moistest and warmest spring on record, over large areas covering the Indian Ocean, the Ross Sea and the Weddell Sea. In October 2016, the positive anomalies of the totally integrated water vapor (IWV) and 2 m air temperature (T2m) over the Indian Ocean, western Pacific, Bellingshausen Sea and southern part of Ross Sea were unprecedented in the last 39 years. In October and November 2016, when the largest magnitude of negative daily sea ice concentration anomalies was observed, repeated episodes of poleward advection of warm and moist air took place. These results suggest the importance of moist and warm air intrusions into the Antarctic region as one of the main contributors to this exceptional sea ice retreat event.

scholarly journals Moisture transport and Antarctic sea ice: Austral spring 2016 event

2017 ◽  
Author(s):  
Monica Ionita ◽  
Patrick Scholz ◽  
Klaus Grosfeld ◽  
Renate Treffeisen
Keyword(s):  
Indian Ocean ◽  
Sea Ice ◽  
Ross Sea ◽  
Weddell Sea ◽  
Antarctic Region ◽  
Austral Spring ◽  
Ice Retreat ◽  
The Indian Ocean ◽  
Sea Ice Retreat ◽  
The Antarctic

Abstract. In austral spring 2016 the Antarctic region experienced anomalous sea ice retreat in all sectors, with sea ice extent in October and November 2016 being the lowest in the Southern Hemisphere over the observational record (1979–present). The extreme sea ice retreat was accompanied by widespread warming along the coastal areas as well as in the interior of the Antarctic continent. This exceptional event occurred along with a strong negative phase of the Southern Annular Mode (SAM) and the wettest and warmest spring on record, over large areas covering the Indian ocean, the Ross Sea and the Weddell Sea. In October 2016, the positive anomalies of the totally integrated water vapor (IWV) and 2 m air temperature (TT) over the Indian Ocean, Western Pacific, Bellingshausen Sea and southern part of Ross Sea were unprecedented in the last 39 years. In October and November 2016, when the lowest daily sea ice concentration anomalies were observed, repeated episodes of poleward advection of warm and moist air took place, with the most intense episode occurring at the end of November 2016. These results suggest the importance of moist and warm air intrusions into the Antarctic region as one of the main contributors to this exceptional sea ice retreat event.

scholarly journals Timing of sea ice retreat can alter phytoplankton community structure in the western Arctic Ocean

2014 ◽  
Vol 11 (7) ◽  
pp. 1705-1716 ◽  
Author(s):  
A. Fujiwara ◽  
T. Hirawake ◽  
K. Suzuki ◽  
I. Imai ◽  
S.-I. Saitoh
Keyword(s):  
Community Structure ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Phytoplankton Community ◽  
Phytoplankton Community Structure ◽  
Western Arctic Ocean ◽  
Phytoplankton Communities ◽  
Ice Retreat ◽  
Western Arctic ◽  
Sea Ice Retreat

Abstract. This study assesses the response of phytoplankton assemblages to recent climate change, especially with regard to the shrinking of sea ice in the northern Chukchi Sea of the western Arctic Ocean. Distribution patterns of phytoplankton groups in the late summers of 2008–2010 were analysed based on HPLC pigment signatures and, the following four major algal groups were inferred via multiple regression and cluster analyses: prasinophytes, diatoms, haptophytes and dinoflagellates. A remarkable interannual difference in the distribution pattern of the groups was found in the northern basin area. Haptophytes dominated and dispersed widely in warm surface waters in 2008, whereas prasinophytes dominated in cold water in 2009 and 2010. A difference in the onset date of sea ice retreat was evident among years–the sea ice retreat in 2008 was 1–2 months earlier than in 2009 and 2010. The spatial distribution of early sea ice retreat matched the areas in which a shift in algal community composition was observed. Steel-Dwass's multiple comparison tests were used to assess the physical, chemical and biological parameters of the four clusters. We found a statistically significant difference in temperature between the haptophyte-dominated cluster and the other clusters, suggesting that the change in the phytoplankton communities was related to the earlier sea ice retreat in 2008 and the corollary increase in sea surface temperatures. Longer periods of open water during the summer, which are expected in the future, may affect food webs and biogeochemical cycles in the western Arctic due to shifts in phytoplankton community structure.

scholarly journals The Response of the Nordic Seas to Wintertime Sea-ice Retreat

2021 ◽  
pp. 1-40
Author(s):  
Yue Wu ◽  
David P. Stevens ◽  
Ian A. Renfrew ◽  
Xiaoming Zhai
Keyword(s):  
Global Warming ◽  
Sea Ice ◽  
Climate Model ◽  
Sea Temperature ◽  
Nordic Seas ◽  
Ocean Response ◽  
Marginal Ice Zone ◽  
Ice Retreat ◽  
Ice Edge ◽  
Sea Ice Retreat

AbstractThe ocean response to wintertime sea-ice retreat is investigated in the coupled climate model HiGEM. We focus on the marginal ice zone and adjacent waters of the Nordic Seas, where the air-sea temperature difference can be large during periods of off-ice winds promoting high heat flux events. Both control and transient climate model ensembles are examined, which allows us to isolate the ocean response due to sea-ice retreat from the response due to climate change. As the wintertime sea-ice edge retreats towards the Greenland coastline, it exposes waters that were previously covered by ice which enhances turbulent heat loss and mechanical mixing, leading to a greater loss of buoyancy and deeper vertical mixing in this location. However, under global warming, the buoyancy loss is inhibited as the atmosphere warms more rapidly than the ocean which reduces the air-sea temperature difference. This occurs most prominently further away from the retreating ice edge, over the Greenland Sea gyre. Over the gyre the upper ocean also warms significantly, resulting in a more stratified water column and, as a consequence, a reduction in the depth of convective mixing. In contrast, closer to the coast the effect of global warming is overshadowed by the effect of the sea-ice retreat, leading to significant changes in ocean temperature and salinity in the vicinity of the marginal ice zone.

scholarly journals Impacts of large-scale atmospheric circulation changes due to winter sea-ice retreat on Black Carbon transport and deposition to the Arctic

2016 ◽  
Author(s):  
Luca Pozzoli ◽  
Srdan Dobricic ◽  
Simone Russo ◽  
Elisabetta Vignati
Keyword(s):  
Sea Ice ◽  
Atmospheric Circulation ◽  
North Atlantic ◽  
Large Scale ◽  
Southern Oscillation ◽  
The Arctic ◽  
The North ◽  
Ice Retreat ◽  
The North Atlantic Oscillation ◽  
Sea Ice Retreat

Abstract. Winter warming and sea ice retreat observed in the Arctic in the last decades determine changes of large scale atmospheric circulation pattern that may impact as well the transport of black carbon (BC) to the Arctic and its deposition on the sea ice, with possible feedbacks on the regional and global climate forcing. In this study we developed and applied a new statistical algorithm, based on the Maximum Likelihood Estimate approach, to determine how the changes of three large scale weather patterns (the North Atlantic Oscillation, the Scandinavian Blocking, and the El Nino-Southern Oscillation), associated with winter increasing temperatures and sea ice retreat in the Arctic, impact the transport of BC to the Arctic and its deposition. We found that the three atmospheric patterns together determine a decreasing winter deposition trend of BC between 1980 and 2015 in the Eastern Arctic while they increase BC deposition in the Western Arctic. The increasing trend is mainly due to the more frequent occurrences of stable high pressure systems (atmospheric blocking) near Scandinavia favouring the transport in the lower troposphere of BC from Europe and North Atlantic directly into to the Arctic. The North Atlantic Oscillation has a smaller impact on BC deposition in the Arctic, but determines an increasing BC atmospheric load over the entire Arctic Ocean with increasing BC concentrations in the upper troposphere. The El Nino-Southern Oscillation does not influence significantly the transport and deposition of BC to the Arctic. The results show that changes in atmospheric circulation due to polar atmospheric warming and reduced winter sea ice significantly impacted BC transport and deposition. The anthropogenic emission reductions applied in the last decades were, therefore, crucial to counterbalance the most likely trend of increasing BC pollution in the Arctic.

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