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Assessment of trace metals in droppings of Adélie penguins (Pygoscelis adeliae) from different locations of the Antarctic Peninsula area
Get PDFIn recent decades, polar regions of the planet have witnessed an increase in human presence. Antarctica is considered one of the most pristine regions of the world, but it could be affected by pollution owing to anthropogenic activities, particularly in the Antarctic Peninsula. Human presence can increase the levels of some trace metals in Antarctic environments, an issue that needs to be evaluated. To acquire data of trace metal contamination in the Antarctic Peninsula region, concentrations (dry weight) of Cd, Pb, As, Cu, Hg and Zn in fresh excrement of Adélie penguins were determined by atomic absorption spectrophotometry. During the 2012/2013 austral summer, samples were collected from four important nesting sites on the Antarctic Peninsula: Arctowski Base, Kopaitic Island (both sites in the northern Antarctic Peninsula), Yalour Island and Avian Island (both sites in the southern Antarctic Peninsula). Data showed that Adélie penguin excreta had significantly higher levels (mg·kg-1) of As, Cd, Hg, Pb and Cu at Arctowski Base and Kopaitic Island, both sites that have major anthropogenic activities that probably contributed to increased metal levels. The levels of trace metals in Adélie penguins were similar to those reported in excreta of Antarctic species in previous studies, and lower than those in excreta of other Antarctic animals. Data suggest that metals ingested by these penguin species that feed in the sea, end up in terrestrial ecosystems
Seawater nutrient and chlorophyll α distributions near the Great Wall Station, Antarctica
Get PDFWe examined the influences upon nutrient, temperature, salinity and chlorophyll a distributions in Great Wall Cove (GWC) and Ardley Cove (AC), near the Chinese Antarctic Great Wall Station, using measurements taken in January 2013 and other recent data. Nutrient concentrations were high, with phosphate concentrations of 1.94 (GWC) and 1.96 (AC) μmol·L−1, DIN(dissolved inorganic nitrogen) concentrations of 26.36 (GWC) and 25.94 (AC) μmol·L−1 and silicate concentrations of 78.6 (GWC) and 79.3 (AC) μmol·L−1. However, average concentrations of chlorophyll a were low (1.29 μg·L−1, GWC and 1.08 μg·L−1, AC), indicating that this region is a high-nutrient and low-chlorophyll (HNLC) area. Nutrient concentrations of freshwater (stream and snowmelt) discharge into GWC and AC in the austral summer are low, meaning freshwater discharge dilutes the nutrient concentrations in the two coves. Strong intrusion of nutrient-rich water from the Bransfield Current in the south was the main source of nutrients in GWC and AC. Low water temperature and strong wind-induced turbulence and instability in the upper layers of the water column were the two main factors that caused the low phytoplankton biomass during the austral summer
Seasonal variations of sulfur aerosols at Zhongshan Station, East Antarctica
Get PDFObservations of atmospheric methane-sulfonic acid (MSA) and non-sea-salt sulfate (nss-SO4 2−) from December 2010 to November 2011 at Zhongshan Station are presented in this paper. MSA and nss-SO4 2− average concentrations were 24.2 ± 37.9 ng·m-3 (0.5–158.3 ng·m-3 ) and 53.0 ± 82.6 ng·m-3 (not detected [n.d.]) – 395.4 ng·m-3 ), respectively. Strong seasonal variations of MSA and nss-SO4 2−, with maxima in austral summer and minima in winter, were examined. The high concentrations of sulfur compounds in December may be attributed the dimethyl sulfide (DMS) emissions from the marginal ice zone, when open water near the sampling site was important in impacting the sulfur species of January and February at Zhongshan Station. In austral winter, there was almost no phytoplanktonic activity in offshore waters, and atmospheric sulfur compounds likely had long-range transport sources
Phosphorus in the aerosols over oceans transported offshore from China to the Arctic Ocean: Speciation, spatial distribution, and potential sources
Get PDFAtmospheric aerosol samples were collected from July to September 2008 onboard a round-trip cruise over the Eastern China Sea, Japan Sea, Western North Pacific Ocean, and the Arctic Ocean (31.1°N–85.18°N, 122.48°E–146.18°W). Total phosphorus (TP) and total inorganic phosphorus (TIP) were analyzed. The organic phosphorus (OP) was calculated by subtracting TIP from TP. Average concentrations of TP in the East Asia, Western North Pacific and Arctic Ocean were 7.90±6.45, 6.87±6.66 and 7.13±6.76 ng∙m-3, while TIP levels were 6.67±5.02, 6.07±6.58, and 6.23±5.96 along the three regions. TP and TIP levels varied considerably both spatially and temporally over the study extent. TIP was found to be the dominant species in most samples, accounting for 86.6% of TP on average. OP was also a significant fraction of TP due to the primary biogenic aerosol (PBA) contribution. The phosphorus in the atmospheric aerosol over the Arctic Ocean had a higher concentration than previous model simulations. Source apportionment analysis indicates that dust is an important phosphorus source which can be globally transported, and thus dust aerosol may be an important nutrient source in some remote regions
Variation characteristics of carbon monoxide and ozone over the course of the 2014 Chinese National Arctic Research Expedition
Get PDFThe concentrations of carbon monoxide and ozone in the marine boundary layer were measured during the 6th Chinese National Arctic Research Expedition (from July to September, 2014). Carbon monoxide concentration ranged between 47.00 and 528.52 ppbv with an average of 103.59 ± 40.37 ppbv. A slight decrease with increasing latitude was observed, except for the extremely high values over the East China Sea which may be attributed to anthropogenic emissions. Ozone concentration ranged between 3.27 and 77.82 ppbv with an average of 29.46±10.48 ppbv. Ozone concentration decreased sharply with increasing latitude outside the Arctic Ocean (during both the northward and the southward course), while no significant variation was observed over the Arctic Ocean. The positive correlation between carbon monoxide and ozone in most sections suggests that the ozone in the marine boundary layer mainly originated from photochemical reactions involving carbon monoxide
Characterizing proteases in an Antarctic Janthinobacterium sp. isolate: Evidence of a protease horizontal gene transfer event
Get PDFWe report the isolation of a cold-adapted bacterium belonging to the genus Janthinobacterium (named AU11), from a water sample collected in Lake Uruguay (King George Island, South Shetlands). AU11 (growth between 4°C and 30°C) produces a single cold-active extracellular protease (ExPAU11), differentially expressed at low temperature. ExPAU11 was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS) as an alkaline metallo-protease (70% coverage with an extracellular protease of Janthinobacterium sp. PI12), and by protease-inhibitor screening identified as a serine-protease. To the best of our knowledge this is the first experimental evidence of a cold-active extracellular protease produced by Janthinobacterium. Furthermore, we identified a serine-protease gene (named JSP8A) showing 60% identity (98% query coverage) to subtilisin peptidases belonging to the S8 family (S8A subfamily) of many cyanobacteria. A phylogenetic analysis of the JSP8A protease, along with related bacterial protein sequences, confirms that JSP8A clusters with S8A subtilisin sequences from different cyanobacteria, and is clearly separated from S8A bacterial sequences of other phyla (including its own). An analysis of the genomic organization around JSP8A suggests that this protease gene was acquired in an event that duplicated a racemase gene involved in transforming L- to D-amino acids. Our results suggest that AU11 probably acquired this subtilisin-like protease gene by horizontal gene transfer (HGT) from a cyanobacterium. We discuss the relevance of a bacterial protease-HGT in the Antarctic environment in light of this hypothesis
Methodological approach to the isolation of functionally active proteins from the tissues of marine hydrobionts: an example of Adamussium colbecki
Get PDFEnzymes from cold-adapted organisms have significant application potential. Because of their unique properties they have been found to be useful in various industries. Despite indisputable practical interest, cold active enzymes also represent a valuable model for fundamental research into protein folding and catalysis. Many investigators have focused their attention on marine hydrobionts, which are growing in importance as a promising source of enzymes. The nature of the source not only determines the availability and the cost of biomolecules of interest but also determines the choice of method for their extraction. A simple and convenient methodological approach of two-stage extraction of proteins has been tested on the Antarctic marine hydrobiont—Adamussium colbecki. This method extracts enough effective protein directly from primary raw materials, as well as when using leftover crude precipitates. The electrophoretic pattern of proteins showed the presence of molecules in a wide range of molecular weights in the samples of A. colbecki after the first and the second stage of extraction. The general proteolytic activity in the first and the second extracts were examined using a zymogram technique. Our experiments revealed that the second extract of A. colbecki contained thermo stable protease exhibiting a molecular weight of 95 kDa in a gelatin zymogram. Further biochemical assays, using different substrates, were conducted to partially identify the types of hydrolases present in the first and the second extracts. Our results revealed the presence of enzymes with collagenolytic and some amylolytic activities preserved in the second extracts. But no esterase or amidase trypsin-like activities were found in the second extract, in contrast to the first extract where this type of activity was significant
Arctic Science Summit Week Conference 2015, Session Report For ISAR-4 and ICARP III Sessions
Get PDFThe Arctic Science Summit Week (ASSW) Session Report. ASSW is the annual gathering of the international organizations engaged in supporting and facilitating Arctic research. The purpose of the summit is to provide opportunities for coordination, collaboration and cooperation in all areas of Arctic science. The summit attracts scientists, students, policy makers and other professionals from all over the world
Arctic Yearbook 2015 -- Arctic Governance and Governing
Get PDFPreface - Arctic Governance
Fran Ulmer
“The most important thing for people to know about the governance of the Arctic is that we have a chance now to act to maintain the integrity of the system or to lose it. To lose it means that we will dismember the vital systems that make the Arctic work. It's not just a cost to the people who live there. It's a cost to all people everywhere.” -Sylvia Earle
Governance is “the processes of interaction and decision-making among the actors involved in a collective problem that lead to the creation, reinforcement, or reproduction of social norms and institutions.”2 In short, it’s the effort to make good decisions for society
