scholarly journals Ocean–atmosphere exchange of organic carbon and CO<sub>2</sub> surrounding the Antarctic Peninsula

2014 ◽  
Vol 11 (10) ◽  
pp. 2755-2770 ◽  
Author(s):  
S. Ruiz-Halpern ◽  
M. Ll. Calleja ◽  
J. Dachs ◽  
S. Del Vento ◽  
M. Pastor ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Antarctic Peninsula ◽  
Austral Summer ◽  
Migration Patterns ◽  
Chl A ◽  
Diel Cycles ◽  
Antarctic Waters ◽  
Gaseous Fraction ◽  
The Antarctic

Abstract. Exchangeable organic carbon (OC) dynamics and CO2 fluxes in the Antarctic Peninsula during austral summer were highly variable, but the region appeared to be a net sink for OC and nearly in balance for CO2. Surface exchangeable dissolved organic carbon (EDOC) measurements had a 43 ± 3 (standard error, hereafter SE) μmol C L−1 overall mean and represented around 66% of surface non-purgeable dissolved organic carbon (DOC) in Antarctic waters, while the mean concentration of the gaseous fraction of organic carbon (GOC H–1) was 46 ± 3 SE μmol C L−1. There was a tendency towards low fugacity of dissolved CO2 (fCO2-w) in waters with high chlorophyll a (Chl a) content and high fCO2-w in areas with high krill densities. However, such relationships were not found for EDOC. The depth profiles of EDOC were also quite variable and occasionally followed Chl a profiles. The diel cycles of EDOC showed two distinct peaks, in the middle of the day and the middle of the short austral dark period, concurrent with solar radiation maxima and krill night migration patterns. However, no evident diel pattern for GOC H–1 or CO2 was observed. The pool of exchangeable OC is an important and active compartment of the carbon budget surrounding the Antarctic Peninsula and adds to previous studies highlighting its importance in the redistribution of carbon in marine environments.

scholarly journals Ocean-atmosphere exchange of organic carbon and CO<sub>2</sub> in the Antarctic Peninsula – physical and biological controls

2013 ◽  
Vol 10 (10) ◽  
pp. 16173-16211
Author(s):  
S. Ruiz-Halpern ◽  
M. L. Calleja ◽  
J. Dachs ◽  
S. Del Vento ◽  
M. Pastor ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Antarctic Peninsula ◽  
Austral Summer ◽  
Co2 Fluxes ◽  
Migration Patterns ◽  
Chl A ◽  
Diel Cycles ◽  
Partial Pressures ◽  
The Antarctic

Abstract. Exchangeable organic carbon (OC) dynamics and CO2 fluxes in the Antarctic Peninsula region during austral summer are highly variable. By stations, the region is a weak source of CO2 to the atmosphere, however, continuous records of CO2 revealed this area as a weak sink. OC fluxes are also in both directions but generally towards the ocean and much higher than CO2 fluxes, sometimes by a factor of 10. Surface exchangeable dissolved organic carbon (EDOC) measurements had a 43 ± 3 μmol C L−1 overall mean, while the gaseous organic carbon equilibrated in water as given by the Henry's Law constant (H') resulted in (GOC H'−1) concentrations of 46 ± 3 μmol C L−1. EDOC represents around 66% of surface dissolved organic carbon (DOC) in Antarctic waters. There is a tendency towards low partial pressures of CO2 in waters with high Chlorophyll a (Chl a) content and high fCO2 in areas with high krill densities. However, such relationships were not found for EDOC. Depth profiles of EDOC were also quite variable and followed Chl a profiles, but only in some instances, while diel cycles of EDOC revealed two distinct peaks around midday and middle of the short austral dark period concurrent with solar radiation maxima and krill night migration patterns. However, there was no evident diel pattern for GOC H'−1. The pool of exchangeable OC reveals itself as an important compartment of the carbon budget in the Antarctic Peninsula and adds to previous studies highlighting its importance in the redistribution of carbon in marine environments.

scholarly journals An Assessment of ERA5 Reanalysis for Antarctic Near-Surface Air Temperature

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 217
Author(s):  
Jiangping Zhu ◽  
Aihong Xie ◽  
Xiang Qin ◽  
Yetang Wang ◽  
Bing Xu ◽  
...  
Keyword(s):  
Linear Relationship ◽  
Antarctic Peninsula ◽  
Austral Summer ◽  
Correlation Coefficients ◽  
East Antarctica ◽  
West Antarctica ◽  
Austral Spring ◽  
Reanalysis Dataset ◽  
Near Surface ◽  
The Antarctic

The European Center for Medium-Range Weather Forecasts (ECMWF) released its latest reanalysis dataset named ERA5 in 2017. To assess the performance of ERA5 in Antarctica, we compare the near-surface temperature data from ERA5 and ERA-Interim with the measured data from 41 weather stations. ERA5 has a strong linear relationship with monthly observations, and the statistical significant correlation coefficients (p < 0.05) are higher than 0.95 at all stations selected. The performance of ERA5 shows regional differences, and the correlations are high in West Antarctica and low in East Antarctica. Compared with ERA5, ERA-Interim has a slightly higher linear relationship with observations in the Antarctic Peninsula. ERA5 agrees well with the temperature observations in austral spring, with significant correlation coefficients higher than 0.90 and bias lower than 0.70 °C. The temperature trend from ERA5 is consistent with that from observations, in which a cooling trend dominates East Antarctica and West Antarctica, while a warming trend exists in the Antarctic Peninsula except during austral summer. Generally, ERA5 can effectively represent the temperature changes in Antarctica and its three subregions. Although ERA5 has bias, ERA5 can play an important role as a powerful tool to explore the climate change in Antarctica with sparse in situ observations.

scholarly journals Antarctic krill as a source of dissolved organic carbon to the Antarctic ecosystem

2011 ◽  
Vol 56 (2) ◽  
pp. 521-528 ◽  
Author(s):  
Sergio Ruiz-Halpern ◽  
Carlos M. Duarte ◽  
Antonio Tovar-Sanchez ◽  
Marcos Pastor ◽  
Burkhard Horstkotte ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Antarctic Krill ◽  
Antarctic Ecosystem ◽  
The Antarctic

Stratigraphy of Antarctic late Cenozoic pectinid-bearing deposits

1998 ◽  
Vol 10 (2) ◽  
pp. 161-170 ◽  
Author(s):  
H.A. Jonkers
Keyword(s):  
Southern Ocean ◽  
Food Availability ◽  
Habitat Loss ◽  
Antarctic Peninsula ◽  
East Antarctica ◽  
Combined Effects ◽  
Late Cenozoic ◽  
Late Pliocene ◽  
Antarctic Waters ◽  
The Antarctic

Antarctic late Cenozoic pectinid-bearing sedimentary strata are chiefly confined to localities in the northern part of the Antarctic Peninsula, in the McMurdo Sound area, and Marine Plain, East Antarctica. Ages of these deposits range from Oligocene to Holocene. Chlamys-like scallops, which are absent from today's Southern Ocean, thrived in Antarctic waters during both glacial and interglacial episodes, but disappeared during the Late Pliocene. Their extinction is believed to result from the combined effects of increased carbonate solubility, habitat loss and limitations in food availability, associated with major cooling.

Behaviour and dive times of Arnoux's beaked whales, Berardius arnuxii, at narrow leads in fast ice

1996 ◽  
Vol 74 (2) ◽  
pp. 388-393 ◽  
Author(s):  
R. P. Hobson ◽  
A. R. Martin
Keyword(s):  
Sea Ice ◽  
Antarctic Peninsula ◽  
Austral Summer ◽  
Food Resources ◽  
Breath Hold ◽  
Beaked Whale ◽  
Horizontal Movement ◽  
Beaked Whales ◽  
Fast Ice ◽  
The Antarctic

Groups of the little-known Arnoux's beaked whale, Berardius arnuxii, were observed at narrow cracks or leads in sea ice near the Antarctic peninsula during the austral summer of 1992–1993. The whales were grey, had a slightly asymmetric blowhole and blow, and were heavily scarred in adulthood. At least 30 animals were uniquely identified using their scars. Despite often cramped conditions at the breathing holes, the whales were always calm and nonaggressive, reacting to the circumstances with surfacing and submerging behaviour involving little horizontal movement. Seventy dive durations by 17 identified adults were recorded, with a mode of 35–65 min and a maximum of at least 70 min. Eight periods of respiration varied between 1.2 and 6.8 min, with an average of 9.6 blows/min. These breath-hold characteristics confirm B. arnuxii as one of the most accomplished mammalian divers, capable of swimming up to an estimated 7 km between breathing sites in sea ice. Whales moved to and from the observed lead, apparently able to find other breathing sites in what appeared to be unbroken ice. The species seems well adapted to life in ice-covered waters and may be able to exploit food resources inaccessible to other predators in the region.

scholarly journals The AEMET-<i>γ</i>SREPS over the Antarctic Peninsula and the impact of kilometric-resolution EPS on logistic activities on the continent

2020 ◽  
Vol 17 ◽  
pp. 209-217
Author(s):  
Sergi Gonzalez ◽  
Alfons Callado ◽  
Mauricia Martínez ◽  
Benito Elvira
Keyword(s):  
Boundary Conditions ◽  
Antarctic Peninsula ◽  
Positive Impact ◽  
Austral Summer ◽  
Added Value ◽  
Ensemble Prediction ◽  
Prediction Systems ◽  
Nwp Model ◽  
The Antarctic ◽  
The Impact

Abstract. Kilometric-resolution Ensemble Prediction Systems (EPSs) will be the new state-of-the-art forecasting tools for short-range prediction in the following decade. Their value will be even greater in Antarctica due to the increasingly demanding weather forecasts for logistic services. During the 2018–2019 austral summer (1 December–31 March), coinciding with the Southern Hemisphere Special Observation Period of the Year of Polar Prediction (YOPP), the 2.5 km AEMET-γSREPS was operationally integrated over the Antarctic Peninsula. In particular, the Antarctic version of γSREPS comes up with crossing four non-hydrostatic convection-permitting NWP models at 2.5 km with three global NWP driving models as boundary conditions. The γSREPS forecasting system has been validated in comparison with ECMWF EPS. It is concluded that γSREPS has an added value to ECMWF EPS due to both its higher resolution and its multi-boundary conditions and multi-NWP model approach. γSREPS performance has a positive impact on logistic activities at research stations and its design may contribute to polar prediction research.

Influence of catchment topography on water chemistry in southeastern Québec Shield lakes

1997 ◽  
Vol 54 (10) ◽  
pp. 2215-2227 ◽  
Author(s):  
Pierre D'Arcy ◽  
Richard Carignan
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Water Chemistry ◽  
Surface Waters ◽  
Overland Flow ◽  
Canadian Shield ◽  
Chl A ◽  
Lake Water Chemistry ◽  
High Runoff ◽  
Shield Lakes

For 30 Canadian Shield lakes of southeastern Quebec, catchment slope and lake morphometry account for 50-70% of the variability of chlorophyll a (Chl a), dissolved organic carbon (DOC), total phosphorus (TP), NO3- , and NH4+ . Dissolved organic carbon, TP, Chl a, Ca, and Mg are negatively related to catchment slope, whereas NO3- and NH4+ increase with increasing slope. Concentrations of more conservative constituents (SO42-, Na, K) increase with decreasing elevation as a result of higher evapotranspiration and lower precipitation at low elevations. Catchment variables (slope, drainage area, percent wetlands) are as good predictors of Chl a (r2 = 0.7) as are water chemistry variables (TP, Ca, Mg, and pH). Dominant vegetation (deciduous vs. coniferous) has little or no influence on lake water chemistry. Hydrogeological data for the Canadian Shield suggest that, during periods of high runoff, the development of waterlogged areas and the importance of overland flow on saturated soils are inversely proportional to catchment slope. We propose that the strong influence of catchment slope on water quality is due to slope-dependent seasonal waterlogging, which determines the fate (retention or export to surface waters) of dissolved substances produced within and moving through the forest floor.

scholarly journals Seasonal variations in concentration and lability of dissolved organic carbon in Tokyo Bay

2015 ◽  
Vol 12 (1) ◽  
pp. 269-279 ◽  
Author(s):  
A. Kubo ◽  
M. Yamamoto-Kawai ◽  
J. Kanda
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
River Water ◽  
Seasonal Variations ◽  
Relative Concentration ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Tokyo Bay ◽  
Chl A

Abstract. Concentrations of recalcitrant and bioavailable dissolved organic carbon (DOC) and their seasonal variations were investigated at three stations in Tokyo Bay, Japan, and in two freshwater sources flowing into the bay. On average, recalcitrant DOC (RDOC), as a remnant of DOC after 150 days of bottle incubation, accounted for 78% of the total DOC in Shibaura sewage treatment plant (STP) effluent, 67% in the upper Arakawa River water, 66% in the lower Arakawa River water, and 78% in surface bay water. Bioavailable DOC (BDOC) concentrations, defined as DOC minus RDOC, were lower than RDOC at all stations. In freshwater environments, RDOC concentrations were almost constant throughout the year. In the bay, RDOC was higher during spring and summer than in autumn and winter because of freshwater input and biological production. The relative concentration of RDOC in the bay derived from phytoplankton, terrestrial, and open-oceanic waters was estimated to be 8–10, 21–32, and 59–69%, respectively, based on multiple regression analysis of RDOC, salinity, and chl a. In addition, comparison with previous data from 1972 revealed that concentrations of RDOC and BDOC have decreased by 33 and 74% at freshwater sites and 39 and 76% in Tokyo Bay, while the ratio of RDOC to DOC has increased. The change in DOC concentration and composition was probably due to increased amounts of STP effluent entering the system. Tokyo Bay exported mostly RDOC to the open ocean because of the remineralization of BDOC.

Late Holocene advance of the Müller Ice Shelf, Antarctic Peninsula: sedimentological, geochemical and palaeontological evidence

1995 ◽  
Vol 7 (2) ◽  
pp. 159-170 ◽  
Author(s):  
Eugene W. Domack ◽  
Scott E. Ishman ◽  
Andrew B. Stein ◽  
Charles E. McClennen ◽  
A.J. Timothy Jull
Keyword(s):  
Antarctic Peninsula ◽  
Deep Water ◽  
Sediment Cores ◽  
Austral Summer ◽  
Ice Age ◽  
Geochemical Data ◽  
Organic Carbon Content ◽  
Ice Shelf ◽  
Circumpolar Deep Water ◽  
The Antarctic

Marine sediment cores were obtained from in front of the Müller Ice Shelf in Lallemand Fjord, Antarctic Peninsula in the austral summer of 1990–91. Sedimentological and geochemical data from these cores document a warm period that preceded the advance of the Müller Ice Shelf into Lallemand Fjord. The advance of the ice shelf is inferred from a reduction in the total organic carbon content and an increase in well-sorted, aeolian, sand in cores proximal to the present calving line. This sedimentological change is paralleled by a change in the foraminiferal assemblages within the cores. Advance of the ice shelf is indicated by a shift from assemblages dominated by calcareous benthic and planktonic forms to those dominated by agglutinated forms. A 14C chronology for the cores indicates that the advance of the Müller Ice Shelf took place c. 400 years ago, coincident with glacier advances in other high southern latitude sites during the onset of the Little Ice Age. Ice core evidence, however, documents this period as one of warmer temperatures for the Antarctic Peninsula. We suggest that the ice shelf advance was linked to the exclusion of circumpolar deep water from the fjord. This contributed to increased mass balance of the ice shelf system by preventing the rapid undermelt that is today associated with warm circumpolar deep water within the fjord. We also document the recent retreat of the calving line of the Müller Ice Shelf that is apparently in response to a recent (four decade long) warming trend along the western side of the Antarctic Peninsula.

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