Antarctic harpacticoids exploit different trophic niches: a summer snapshot using fatty acid trophic markers (Potter Cove, King George Island)

2017 ◽  
Vol 568 ◽  
pp. 59-71
Author(s):  
E Werbrouck ◽  
A Vanreusel ◽  
D Deregibus ◽  
D Van Gansbeke ◽  
M De Troch
Keyword(s):  
Fatty Acid ◽  
King George Island ◽  
Potter Cove ◽  
Trophic Markers ◽  
Trophic Niches

Trophic niches determined from fatty acid profiles of sympatric coral reef mesopredators

2019 ◽  
Vol 632 ◽  
pp. 159-174 ◽  
Author(s):  
SL Bierwagen ◽  
H Pethybridge ◽  
MR Heupel ◽  
A Chin ◽  
CA Simpfendorfer
Keyword(s):  
Fatty Acid ◽  
Coral Reef ◽  
Fatty Acid Profiles ◽  
Trophic Niches

On the competitive balance of macroalgae at Potter Cove (King George Island, South Shetlands)

Polar Biology ◽  
1994 ◽  
Vol 14 (1) ◽  
Author(s):  
H. Kl�ser ◽  
G. Mercuri ◽  
F. Laturnus ◽  
M.L. Quartino ◽  
C. Wiencke
Keyword(s):  
Competitive Balance ◽  
King George Island ◽  
Potter Cove ◽  
South Shetlands

Fatty acid trophic markers in Lake Baikal phytoplankton: A comparison of endemic and cosmopolitan diatom-dominated phytoplankton assemblages

2018 ◽  
Vol 85 ◽  
pp. 878-886 ◽  
Author(s):  
Sergey M. Shishlyannikov ◽  
Alyona A. Nikonova ◽  
Yuri S. Bukin ◽  
Alexander G. Gorshkov
Keyword(s):  
Fatty Acid ◽  
Lake Baikal ◽  
Phytoplankton Assemblages ◽  
Trophic Markers

Population dynamics of the bivalve Laternula elliptica from Potter Cove, King George Island, South Shetland Islands

1998 ◽  
Vol 10 (2) ◽  
pp. 153-160 ◽  
Author(s):  
H.-Jörg Urban ◽  
Guillermo Mercuri
Keyword(s):  
Population Dynamics ◽  
Growth Parameters ◽  
Total Mortality ◽  
Growth Function ◽  
South Shetland Islands ◽  
King George Island ◽  
Potter Cove ◽  
Cycle Growth ◽  
Laternula Elliptica ◽  
Complete Study

Body size, geographical distribution and biomass make Laternula elliptica one of the most important bivalve species of the Antarctic. A complete study on the population dynamics (reproduction cycle, growth, mortality and productivity) of this species from King George Island gave growth parameters for the von-Bertalanffy-growth-function of: L∞ = 112.2 mm, K = 0.160 yr 1, t0 = 0.000 yr. Total mortality was estimated as Z = 0.392 yr−1. Somatic production and mean biomass of two distinct sub-populations were 8.7 and 67.3 g AFDW m−2 yr−1 at Beach & Glacier and 20.0 and 88.6 g AFDW m−2 yr−1 at Punta Elefante. The following P / B values were calculated; Beach & Glacier = 0.129, Punta Elefante = 0.226. It is suggested that these differences are linked to mortality caused by icebergs which is expected to be higher at the shallower Punta Elefante site.

Iron transport by subglacial meltwater indicated by stable iron isotopes in fjord sediments of King George Island, Antarctica

2020 ◽  
Author(s):  
Jan Hartmann ◽  
Susann Henkel ◽  
Sabine Kasten ◽  
Adrián Silva Busso ◽  
Michael Staubwasser
Keyword(s):  
Iron Transport ◽  
Data Availability ◽  
Glacier Retreat ◽  
King George Island ◽  
Strong Argument ◽  
Potter Cove ◽  
Fe Oxides ◽  
Subglacial Meltwater ◽  
Subglacial Environments

<p>Polar regions are critical for future climate evolution, and they experience major environmental changes. A particular focus of biogeochemical investigations in these regions lies on iron (Fe). This element drives primary productivity and, thus, the uptake of atmospheric CO<sub>2</sub> in vast areas of the ocean. Due to the Fe-limitation of phytoplankton growth in the Southern Ocean, Antarctica is a key region for studying the change of iron fluxes as glaciers progressively melt away. The respective climate feedbacks can currently hardly be quantified because data availability is low, and iron transport and reaction pathways in Polar coastal and shelf areas are insufficiently understood. We show how novel stable Fe isotope techniques, in combination with other geochemical analyses, can be used to identify iron discharges from subglacial environments and how this will help us assessing short and long term impacts of glacier retreat on coastal ecosystems.</p><p>Stable Fe isotopes (δ<sup>56</sup>Fe) may be used to trace Fe sources and reactions, but respective data availability is low. In addition, there is a need to constrain δ<sup>56</sup>Fe endmembers for different types of sediments, environments, and biogeochemical processes.</p><p>δ<sup>56</sup>Fe data from pore waters and sequentially extracted solid Fe phases at two sites in Potter Cove (King George Island, Antarctica), a bay affected by fast glacier retreat, are presented. Close to the glacier front, sediments contain high amounts of easily reducible Fe oxides and show a dominance of ferruginous conditions compared to sediments close to the ice-free coast, where surficial oxic meltwater discharges and sulfate reduction dominates. We suggest that high amounts of reducible Fe oxides close to the glacier mainly derive from subglacial sources, where Fe liberation from comminuted material beneath the glacier is coupled to biogeochemical weathering. A strong argument for a subglacial source is the predominantly negative δ<sup>56</sup>Fe signature of reducible Fe oxides that remains constant throughout the ferruginous zone. In situ dissimilatory iron reduction (DIR) does not significantly alter the isotopic composition of the oxides. The composition of the easily reducible Fe fraction therefore suggests pre-depositional microbial cycling as it occurs in subglacial environments. Sediments influenced by oxic meltwater discharge show downcore trends towards positive δ<sup>56</sup>Fe signals in pore water and reactive Fe oxides, typical for in situ DIR as <sup>54</sup>Fe becomes less available with increasing depth.</p><p>We found that a quantification of benthic Fe fluxes and subglacial Fe discharges based on stable Fe isotope geochemistry will be complicated because (1) diagenetic processes vary strongly at short lateral distances and (2) the variability of δ<sup>56</sup>Fe in subglacial meltwater has not been sufficiently well investigated yet. However, isotope mass balance models that consider the current uncertainties could, in combination with an application of ancillary proxies, lead to a much better quantification of Fe inputs into polar marine waters than currently available. This would consequently allow a better assessment of the flux and fate of Fe originating from the Antarctic Ice Sheet.</p><p><strong>Henkel et al. (2018)</strong> Diagenetic iron cycling and stable Fe isotope fractionation in Antarctic shelf sediments, King George Island. GCA 237, 320-338.</p>

H2O2 accumulation from photochemical production and atmospheric wet deposition in Antarctic coastal and off-shore waters of Potter Cove, King George Island, South Shetland Islands

1999 ◽  
Vol 11 (2) ◽  
pp. 131-139 ◽  
Author(s):  
Doris Abele ◽  
Gustavo A. Ferreyra ◽  
Irene Schloss
Keyword(s):  
Hydrogen Peroxide ◽  
Surface Waters ◽  
Wet Deposition ◽  
High Energy ◽  
South Shetland Islands ◽  
King George Island ◽  
The South ◽  
Potter Cove ◽  
Shetland Islands ◽  
Snowfall Event

Temporal and spatial variations of the hydrogen peroxide accumulation were measured in off-shore waters and in intertidal rockpools near Jubany Station, King George Island, South Shetland Islands. As H2O2 photoformation is mainly driven by the short wavelength radiation in the UV-B and the UV-A range of the solar spectrum, the study was conducted between the beginning of October and the end of December 1995, the period of Antarctic spring ozone depletion. Wet deposition of H2O2 containing snow was identified as a major source of hydrogen peroxide in the surface waters of Potter Cove. As the concentrations of dissolved organic carbon (DOC) in Potter Cove surface waters were low (121 ± 59 μmol Cl−1), when compared to the highly eutrophicated waters on the German Wadden coast (6000–7000 μmol Cl−1), direct UV-induced DOC photo-oxidation was of only limited significance in the Antarctic sampling site. Nonetheless, under experimental conditions, H2O2 photoformation in Potter Cove surface waters amounted to 90 ± 40 nmol H2O2 h−1 l−1 under a UV-transparent quartz plate. When high energy UV-B photons were cut-off by a WG320 filter formation continued at a rate of 66 ± 29 nmol H2O2 h−1 l−1 due to UV-A and visible light photons. Samples from freshly deposited snow contained between 10 000 and 13 600 nmol H2O2 l−1, and a snowfall event in mid November resulted in a maximum concentration of 1450 nmol H2O2 l−1 in the upper 10 cm layer of Potter Cove surface waters. Maximal H2O2 concentrations in intertidal rockpools were even higher and reached up to 2000 nmol H2O2 l−1 after the snowfall event. During a grid survey on December 17 1995, H2O2 concentrations and salinity displayed a north to south gradient, with higher concentrations and PSU at the south coast of the cove. The reasons for this spatial inhomogenety are as yet unknown, but may relate to a minor local input of photo-reactive organic matter from creeks entering the cove in the south-east, as well as to waste water discharge from the station, located on the south beach.

Sign in / Sign up

Export Citation Format

Share Document