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We inferred late Holocene Adélie penguin occupation history and population dynamics on Zolotov Island, Vestfold Hills, Antarctica, using geochemical data from a dated ornithogenic sediment core (ZOL4). Radiocarbon dates on fossil penguin bones in the core indicate that Adélie penguins occupied the island as early as 1,800 years before present (yr BP), following the retreat of the S ørsdal glacier. This occupation began ~1,200 years later than that observed at Ardley Island and King George Island, in the South Shetland Islands. Phosphorus was identified as the most indicative bio-element for penguin guano in core ZOL4, and was used to infer past penguin population dynamics. Around 1,800 years ago, the Adélie penguin populations at both Zolotov Island and Ardley Island increased rapidly and reached their highest levels ~1,000 yr BP. For the past ~900 years, the penguin populations at Zolotov Island have shown a general rising trend, with fluctuations, while those at Ardley Island have shown a moderate decreasing trend. The Adélie penguin populations at both Ardley Island and Zolotov Island showed a clear decline ~300 years ago, which we interpret as a response to the Little Ice Age, or a neoglacial cooling event. [ABSTRACT FROM AUTHOR]

A sediment core was collected from the Fildes Peninsula of Antarctica, which contained numerous seal hairs and was identified to be seal excrement deposition. By analyzing its total organic carbon (TOC) and concentrations of bio-elements, the seal population changes of the past century were reconstructed. The variation of seal population in the last century on the Fildes Peninsula is primarily controlled by human activities. The sealing industry in the early 20th century caused the dramatic decline of seal population. The protection of the Antarctic seals since the 1960s and the reduced seal's competition with whales for prey resources due to whaling lead to the recovery of seal population and make the high level of the seal population sustainable. [ABSTRACT FROM AUTHOR]

For the first time synchrotron radiation X-ray fluorescence (SR-XRF) microanalysis was performed throughout the total length of 4 single barbs from the primaries and secondaries of a snow petrel (Pagodroma Nivea) collected in the Antarctica. Thirteen elements (S, Mg, K, Ca, Fe, Ni, Cu, Zn, Se, Sr, Ba, Hg and Pb) were detected somewhere in the barbs. Variations in levels of these elements within and among the barbs were obvious, indicating nonuniform microscale distributions. Factors influencing the fluctuations of the levels of the elements were investigated using a multivariate statistical analysis method. Five factors (F1 being associated with high loadings of Ca, Sr, and Ni, F2 with high loadings of Fe and Ba, F3 with high loadings of Se and Hg, F4 with high loadings of Ca and K, and F5 with high loadings of Zn and Pb) were found to explain about 80% of the total variance. Results from the factor analysis suggested external contamination of Fe, Ba, Pb, Zn and Hg on the feathers of the snow petrel. [Copyright &y& Elsevier]

Abstract: The concentrations of total mercury (HgT) and three bio-essential elements (phosphor, potassium, sodium) were analyzed in Antarctic seal hairs from a lake core spanning the past 2000 years and collected from King George Island (63°23′S, 57°00 ′W), West Antarctica. The HgT concentration shows a significant fluctuation while the levels of the three bio-essential elements remain almost constant. The rise and fall of the HgT concentration in the seal hairs are found to be closely coincided with ancient activities of gold and silver mining using Hg-amalgamation process around the world, especially in the Southern Hemisphere. Briefly, HgT levels are high during five episodes of extensive gold and silver mining activities—Rome Empire and China Han Dynasty (∼18–300 A.D.), Maya period and China Tang (750–900 A.D.), Incas civilization and Christian Kingdom (1200–1500 A.D.), New world (1650–1800 A.D.), and modern industry period (1840 A.D.–present); they are low during four time periods of reduced gold and silver mining activities—the China Han and Rome fall (since 300 A.D.), Maya fall and Wartime period in China (1050–1250 A.D.), Pizarro coming (ca. 1532 A.D.) and Independence War of South America (1800–1830 A.D.). Two profiles of HgT in other two lake cores, one affected by seal excrements and the other by penguin droppings, from the same region are similar to the one in seal hairs. The Hg concentration profile in the seal hairs is significantly correlated with the one in a peat bog of Southern Chile near King George Island. Since Hg is existent mainly at the form of methyl-mercury in seal hairs, this correlation supports a relationship and link between atmospheric mercury concentration and methyl-mercury production. Comparing with samples from American and European continents, the Antarctic seal hairs provide an archive of total mercury concentration in surface seawater of the South Ocean less affected by regional human activities, and this archive may provide a good reference for assessing the global Hg emissions, depositions and recycling in the past thousand years. [Copyright &y& Elsevier]

Abstract: The nitrous oxide emissions were measured at three tundra sites and one snowpack on the Fildes Peninsula in the maritime Antarctic in the summertime of 2002. The average fluxes at two normal tundra sites were 1.1±2.2 and 0.6±1.7μg N2O m−2 h−1, respectively. The average flux from tundra soil site with penguin dropping addition was 3.7±2.0μg N2O m−2 h−1, 3–6 times those from the normal tundra soils, suggesting that the deposition of fresh droppings enhanced N2O emissions during penguin breeding period. The summer precipitation had an important effect on N2O emissions; the flux decreased when heavy precipitation occurred. The diurnal cycle of the N2O fluxes from Antarctic tundra soils was not obtained due to local fluky weather conditions. The N2O fluxes through four snowpack sites were obtained by the vertical N2O concentration gradient and their average fluxes were 0.94, 1.36, 0.81 and 0.85μg N2O m−2 h−1, respectively. The tundra soils under snowpack emitted N2O in the maritime Antarctic and increased local atmospheric N2O concentrations; therefore these fluxes could constitute an important part of the annual N2O budget for Antarctic tundra ecosystem. [Copyright &y& Elsevier]

A geochemical method, mainly based upon analyses of “bio-elements” in the sediments from the inter-zone depression between a penguin colony and tundra vegetation, was proposed and applied to reconstruct the occupation history of a penguin colony in the maritime Antarctic. The results from the samples of Ardley Island and Barton Peninsula revealed a general, seesaw-like relationship between a penguin colony and tundra vegetation and several basic occupation patterns. This method and the results may provide new and valuable information about the history of penguin-colony occupation and the paleoenvironment in the maritime Antarctic. [ABSTRACT FROM AUTHOR]

Presents information on a study which analyzed nitrous oxides in the marine boundary layer in Fildes Peninsula, maritime Antarctica. Details of sampling sites and analysis; Results and discussion; Conclusions.

Heavy metal contaminants in Mirror Peninsula, East Antarctica, have rarely been studied and the source and influencing factors are poorly understood. We sampled a grid of 189 topsoil samples from Mirror Peninsula and analyzed the concentrations of Zn, Cu, U, Cr, Ga, Pb, Hg, Se and As; we also calculated the chemical index of alteration (CIA), a proxy of weathering. The results show that the distributions of Cr, Ga, Cu, and Zn are associated with weathering; the distributions of As and Pb are related to vehicle use and unloading activities at the wharfs, respectively; and the distribution of Hg is likely associated with both anthropogenic impacts and biological activity. The contamination level of these heavy metals in Mirror Peninsula is relatively low and within the controllable range. Both weathering processes and anthropogenic impacts can cause the enrichment of heavy metals; thus reliable source apportionment is crucial in studying heavy metal enrichment and contamination. Image 1093 • Heavy metal contamination levels of topsoils from Mirror Peninsula, East Antarctica, are within the controllable range. • The observed spatial distribution of heavy metal concentrations is related to logistical activities and vehicle use. • Biological activities, including biomagnification along the food chain, are another source. • Enrichment of heavy metal induced by weathering process should be eliminated as natural process. Heavy metal contamination in Mirror Peninsula falls within the controllable range and various factors contributed to the enrichment of heavy metals. [ABSTRACT FROM AUTHOR]

Understanding responses by penguins to climate change in Antarctica is often complicated by other factors including microclimate and landscape effects. Here, we analyze an ornithogenic sediment profile to reconstruct penguin occupation history on the eastern side of Ardley Island, west Antarctic Peninsula, and synthesize the results from various studies on Ardley Island in the past 20 years. Penguins have inhabited the eastern side of this island since about 900 yr BP, with populations significantly increasing from ∼500 yr BP. On the western side, delineated by the Ardley Ridge Line , penguins began to abandon nest or molt sites at ∼1000 yr BP. By the time of 500 yr BP, the abandonment and population decline became a common tendency on the west side. This shift in occupation areas was likely driven by local microclimate and a change in wind patterns causing more snow to accumulate on the west side of the island. We found a linkage between this penguin movement and the Southern Westerly Winds, which became stronger at ∼1000 yr BP and impacted local conditions at Ardley Island, likely induced by more positive Southern Annular Mode (SAM). These results indicate that island topography, wind and snow patterns, combined with large-scale climate forcing can be just as important in determining penguin distribution as temperature and other environmental factors. This study provides a new perspective for investigating the possible impact of microclimate and site topography on penguin behavior. • Penguins moved from the western to the eastern side of Ardley Island from 1000 yr BP. • Enhanced westerlies impacted local microclimate conditions and drove penguins to move. • A new perspective is proposed for investigating the impacts of climate forcing and site topography on penguin distribution. [ABSTRACT FROM AUTHOR]

Abstract: Total mercury (Hg) concentration and several other geochemical parameters were determined for five sediment profiles from the Antarctic Ross Sea region. Our data exhibit significant positive correlations between Hg concentration and total organic carbon (TOC) content in all profiles, suggesting the predominant role of organic matter (OM) as a Hg carrier. The OM in the sediments originates primarily from penguin guano and algae. High Hg content in guano and a positive correlation between Hg and a guano bio-element (phosphorus, P) in the ornithogenic sediment profiles (MB6, BI and CC) indicate that Hg was strongly influenced by guano input. The bottom sediments of MB6 with seal hairs contain relatively high Hg. This increase is attributed to the input of seal excrement, suggesting that sedimentary Hg may be an effective trophic-level indicator from seals to penguins. The enrichment factor (EF) for Hg was calculated and the results indicated apparent Hg enrichment in the sediment profiles from the Ross Sea region caused by bio-vectors such as penguins and seals. Compared with typical sediments from other sites in Antarctica and the SQGs (sediment quality guidelines), the total amount of Hg in our study area is still not considered to be adversely high. [Copyright &y& Elsevier]

Abstract: The total gaseous mercury (TGM) measurements were performed using an automatic Mercury Vapor Analyze (model 2537B) aboard the Chinese research vessel (R/V) XueLong during the 24th China Antarctic Research Expedition from Shanghai, China to Prydz Bay, Antarctica in 2007. TGM ranged between 0.302 and 4.496 ng m−3 with an average of 1.536 ± 0.785 ng m−3 over the entire period. Geographically, TGM in the Northern Hemisphere and the Southern Hemisphere along the cruise path were 1.746 ± 0.513 and 1.471 ± 0.842 ng m−3 in average, respectively. Higher TGM concentrations were observed in the coastal regions outside the polar region due primarily to air masses transported from the adjacent mainland reflecting the contribution from anthropogenic sources. The pronounced episode was recorded when ship passed through Sunda straits, which should be ascribed to the volcano plume and/or biomass burning contamination. In the maritime Antarctic TGM level was in agreement with the values by land-based observation, presenting a diurnal cycle with the maximum around midday and minimum at night. Atmospheric mercury destruction events dominated by the oxidation of atmospheric Hg0 were apparently observed in this region. [Copyright &y& Elsevier]

During the summertime of 2005/2006 net methane fluxes and environmental variables were investigated in two tundra wetlands Wolong Marsh and Tuanjie Marsh of eastern Antarctica, using the closed chamber technique. At Wolong Marsh, the measurements were made at four wet tundra sites, four mesic tundra sites, and two dry sites. flux for wet tundra sites averaged and for the mesic sites . For the dry sites, all the fluxes showed the negative values with an average of . At Tuanjie Marsh, flux measurements were made at two open ponds, two shallow fens and two dry sites. The average flux for the pond sites was and for the fen sites . For the dry sites fluxes were approximately one order of magnitude lower than those for pond and fen sites and averaged . Spatial variations in flux were primarily driven by the water table position at two tundra wetlands, whereas temporal variations in flux from wet and mesic sites were related with the thermal regime of tundra soil layers. The fluxes from six observation sites showed a consistent diurnal cycle with the peak at 14:00 and the lowest at 2:00 (local time), which was correlated with ground temperature at the depth of 0–10cm. The emissions from coastal wetlands could constitute an important part of the annual budget for Antarctic tundra ecosystems. [Copyright &y& Elsevier]

As a result of climate changes, penguins are predicted to be at risk of losing their breeding habitats. Changes in penguin colony distribution suggest that some colonies have withstood environmental changes better than others, serving as initial post-glacial settlements or refuges in adverse climatic conditions. Here we have synthesized over 200 dates (including 91 new dates) of penguin remains and of guano in 107 ornithogenic profiles from abandoned nests on Inexpressible Island, one of the longest persisting Adélie penguin colonies in Antarctica, to investigate the dynamics of population size and the role of this island in the ecological history of this species. The results indicate that, following the retreat of Ross Ice Shelf, the Adélies first colonized this island at ∼8.6 kyr BP, documenting the earliest known breeding site in the Ross Sea since deglaciation. During ∼7-3 kyr BP the reconstructed population on Inexpressible Island was generally consistent with the change in pack ice, reaching relative peaks at 5.5–5.0 and 4.0–3.5 kyr BP. After brief decline at 3.5–3.0 kyr, substantial enlargement of the penguin colony occurred between 3.0 and 1.5 kyr BP, attributed to the immigration from the abandoned colonies along the Scott Coast. During this time, the persistent efficiency of Terra Nova Bay polynya offered conditions favourable to the expansion of the penguin population on Inexpressible Island, which probably represented a refuge area under increased coastal sea-ice. This longest-dwelling penguin colony may provide a valuable refuge for the Adélie penguin if the recurrent Terra Nova Bay polynya persists under future climatic and environmental changes, as occurred in the past. • Inexpressible Island was first colonized by Adélie penguins at 8.6 kyr BP, the earliest in the Ross Sea since deglaciation. • Increasing population at 3.0–1.5 kyr BP corresponds to the abandonment of other colonies in the Ross Sea. • The persistent efficiency of Terra Nova Bay polynya offered a refuge for Adélie penguins under excessive coastal sea-ice. [ABSTRACT FROM AUTHOR]

Abstract: Nitrous oxide (N2O) fluxes across air–water interface were investigated in the littoral zones of three alga-rich lakes (Lake Mochou, Lake Tuanjie and Lake Daming) in east Antarctica during the summers of 2007/2008 and 2008/2009. In the littoral zones of these three lakes, the mean N2O fluxes were 3.1 ± 6.7 μgN2O–N m−2 h−1, 2.5 ± 2.8 μgN2O–N m−2 h−1 and 7.2 ± 6.9 μgN2O–N m−2 h−1, respectively. The fluxes showed a large temporal and spatial variation in lake littoral zones. On the whole, lake littoral zones were the emission sources for atmospheric N2O although negative fluxes occurred on most of the observation sites. The mean flux significantly correlated with NO3 −–N concentration in the sediments at each site, suggesting that spatial variations of N2O fluxes have a connection with NO3 −–N concentration. The seasonal pattern of the flux was positively related to daily radiation and air temperature and negatively to water depth, indicating that these factors and alga activity had an important effect on N2O emissions. The summertime N2O budget across air–water interface was estimated to be 6.7 mg N2O–N m−2, 5.4 mg N2O–N m−2 and 15.6 mg N2O–N m−2 from the littoral zones of Lake Mochou, Lake Tuanjie and Lake Daming, respectively. Our results indicated that lake littoral N2O emissions could have a regional importance in coastal Antarctica. [Copyright &y& Elsevier]

Abstract: During the summertime of 2007/2008, carbon dioxide (CO2) and methane (CH4) fluxes across air–water interface were investigated in the littoral zones of Lake Mochou and Lake Tuanjie, east Antarctica, using a static chamber technique. The mean fluxes of CO2 and CH4 were −70.8 mgCO2 m−2 h−1 and 144.6 μgCH4 m−2 h−1, respectively, in the littoral zone of Lake Mochou; The mean fluxes were −36.9 mgCO2 m−2 h−1 and 109.8 μgCH4 m−2 h−1, respectively, in the littoral zone of Lake Tuanjie. Their fluxes showed large temporal and spatial dynamics. The CO2 fluxes showed a significantly negative correlation with daily total radiation (DTR) and a weakly negative correlation with air temperature and water temperature, indicating that sunlight intensity controlled the magnitude of CO2 fluxes from the open lakes. The CH4 fluxes significantly correlated with local air temperature, water table and total dissolved solids (TDS), indicating that they were the predominant factors influencing CH4 fluxes. Summertime CO2 budgets in the littoral zones of Lake Mochou and Lake Tuanjie were estimated to be −152.9 gCO2 m−2 and −79.7 gCO2 m−2, respectively, and net CH4 emissions were estimated to be 312.3 mgCH4 m−2 and 237.2 mgCH4 m−2, respectively. Our results show that shallow, open, alga-rich lakes might be strong summertime CO2 absorbers and small CH4 emitters during the open water in coastal Antarctica. [Copyright &y& Elsevier]

Abstract: In coastal Antarctica, freezing and thawing influence many physical, chemical and biological processes for ice-free tundra ecosystems, including the production of greenhouse gases (GHGs). In this study, penguin guanos and ornithogenic soil cores were collected from four penguin colonies and one seal colony in coastal Antarctica, and experimentally subjected to three freezing–thawing cycles (FTCs) under ambient air and under N2. We investigated the effects of FTCs on the emissions of three GHGs including nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4). The GHG emission rates were extremely low in frozen penguin guanos or ornithogenic soils. However, there was a fast increase in the emission rates of three GHGs following thawing. During FTCs, cumulative N2O emissions from ornithogenic soils were greatly higher than those from penguin guanos under ambient air or under N2. The highest N2O cumulative emission of 138.24μgN2O–Nkg−1 was observed from seal colony soils. Cumulative CO2 and CH4 emissions from penguin guanos were one to three orders of magnitude higher than those from ornithogenic soils. The highest cumulative CO2 (433.0mgCO2–Ckg−1) and CH4 (2.9mgCH4–Ckg−1) emissions occurred in emperor penguin guanos. Penguin guano was a stronger emitter for CH4 and CO2 while ornithogenic soil was a stronger emitter for N2O during FTCs. CO2 and CH4 fluxes had a correlation with total organic carbon (TOC) and soil/guano moisture (Mc) in penguin guanos and ornithogenic soils. The specific CO2–C production rate (CO2–C/TOC) indicated that the bioavailability of TOC was markedly larger in penguin guanos than in ornithogenic soils during FTCs. This study showed that FTC-released organic C and N from sea animal excreta may play a significant role in FTC-related GHG emissions, which may account for a large proportion of annual fluxes from tundra ecosystems in coastal Antarctica. [Copyright &y& Elsevier]

Only few estimates of nitrous oxide (N2O) emissions are available from Antarctic tundra ecosystems. During the summer of 2005/2006, for the first time field measurements of N2O emissions were conducted by a static chamber technique in two coastal marshes (Wolong Marsh and Tuanjie Marsh) of eastern Antarctica. In Wolong Marsh, the N2O fluxes ranged from −20.6 to 85.6μgN2O-Nm−2 h−1, −5.3 to 50.8μgN2O-Nm−2 h−1 and 6.4 to 27.1μgN2O-Nm−2 h−1 at the wet, mesic and dry sites, respectively. In Tuanjie Marsh, the fluxes ranged from −5.9 to 12.6μgN2O-Nm−2 h−1, −3.6 to 12.1μgN2O-Nm−2 h−1 and 12.8 to 59.8μgN2O-Nm−2 h−1 at the ponds, shallow fens and dry tundra sites, respectively. The seasonal pattern of N2O fluxes followed the warming of the sediment/soil, indicating that the variation of ground temperatures had an important effect on N2O emissions. The freezing–thawing cycle seemed to increase the N2O emissions from the wetlands, and water table was the major parameter for spatial variations of controlling N2O fluxes. There was a consistent diurnal pattern in the N2O emission rates from two wetlands and a good correlation with ground temperatures. The sparse data in this study hint at the potential importance of coastal tundra wetlands in the total local atmospheric N2O load in eastern Antarctica. [Copyright &y& Elsevier]

The gas phosphine (PH3) is a part of an atmospheric link of the phosphorus cycle on earth. Previous research reported the terrestrial lower tropospheric PH3 at night in the 1ngm−3 range in remote areas, with the peak of 100ngm−3 in populated areas, and at daytime even lower concentrations in the pgm−3 range. The data of the global marine atmospheric PH3 are still very sparse. This study presents surprisingly high concentrations of PH3 in the order of 0. 1–1μgm−3 in many of 32 samples of the marine atmosphere in the latitudinal range from 30°N to 65°S (the cruise of research ship Xuelong from Shanghai Harbor, China, to Antarctica). The highest concentrations were measured near coastal areas of Eastern Asia and Western Australia. A significant correlation exists between marine atmospheric PH3 concentration and air temperature at 22:00 (local time). PH3 concentrations at different latitudes strongly decline with daylight intensity according to a logarithmic relationship. These surprisingly high concentrations of the readily oxidizable PH3 in the air indicate hitherto unknown but important PH3 emission sources in marine environment. More work is necessary to evaluate the sources of atmospheric PH3 from marine biosphere. [Copyright &y& Elsevier]

Drastic climate change is widely believed to threaten the ecological security of penguins. Previous studies have concluded that penguins on the Scott Coast, southern Ross Sea, disappeared from ∼2000 yr BP; two opposite hypotheses of "cooling" and "warming" have been proposed for the disappearance. Here, by identifying penguin guano and remains such as eggshell fragments, bones and feathers in a sediment profile from Dunlop Island, we found that this island was not abandoned at ∼2000 yr BP. In addition, sedimentological evidence from Cape Ross deduced the permanent snow/ice cover at ∼1700 yr BP, which is consistent with a Neoglacial cooling period on the Scott Coast. We suggest that Neoglacial cooling caused the widespread abandonment of penguin colonies on the Scott Coast, by the increased coastal sea ice and/or snow/ice accumulation. However, penguins persisted at particular localities due to specific topographical or oceanic conditions shielding them from the impacts of snow and ice. • Neoglacial cooling caused wide abandonment of penguin colonies on the Scott Coast by increased sea ice and/or snow/ice cover. • Penguins did not completely disappear from the Scott Coast at ∼2000 yr BP. • Penguins persisted at some localities with specific topographical or oceanic conditions. [ABSTRACT FROM AUTHOR]