Holocene occupation history of pygoscelid penguins at Stranger Point, King George (25 de Mayo) Island, northern Antarctic Peninsula

We report additional fossil evidence for pygoscelid penguins breeding on King George (25 de Mayo) Island, South Shetland Islands, in the Holocene beginning at ~7000 cal. yr BP. This evidence comes from a raised marine beach deposit formerly studied and described as Pingfo I at Stranger Point, Potter Peninsula. We relocated and exposed deposits at this site and recovered additional samples of penguin bones from five stratigraphic beds that are redescribed here. Most of these bones are from juvenile penguins and exhibit little or no wear indicating minimal transport to the beach deposits. Some of the bones are developed enough to be identifiable to Adélie ( Pygoscelis adeliae), Gentoo ( Pygoscelis papua), and Chinstrap ( Pygoscelis antarctica) penguins, indicating that all three species were breeding at Stranger Point from ~7320 to 4865 cal. yr BP. This breeding occupation corresponds with the first warming and deglaciation that occurred in the northern Antarctic Peninsula by this time and ends with the onset of reglaciation of the Peninsula. At least 31 abandoned penguin mounds and ornithogenic soils also were located and sampled at Stranger Point and indicate that the current occupation of this area by all three pygoscelid penguins dates no older than ~535 cal. yr BP. The absence of ornithogenic soils from earlier Holocene breeding was probably due to glacial activity and soil solifluction during periods of warming in the mid to late Holocene.

Draft Genome of Shewanella frigidimarina Ag06-30, a Marine Bacterium Isolated from Potter Peninsula, King George Island, Antarctica

We present the draft genome of Shewanella frigidimarina Ag06-30, a marine bacterium from King George Island, Antarctica, which encodes the carbapenemase SFP-1. The assembly contains 4,799,218 bp (G+C content 41.24%). This strain harbors several mobile genetic elements that provide insight into lateral gene transfer and bacterial plasticity and evolution.

Soil–landform–plant-community relationships of a periglacial landscape on Potter Peninsula, maritime Antarctica

Integrated studies on the interplay between soils, periglacial geomorphology and plant communities are crucial for the understanding of climate change effects on terrestrial ecosystems of maritime Antarctica, one of the most sensitive areas to global warming. Knowledge on physical environmental factors that influence plant communities can greatly benefit studies on the monitoring of climate change in maritime Antarctica, where new ice-free areas are being constantly exposed, allowing plant growth and organic carbon inputs. The relationship between topography, plant communities and soils was investigated on Potter Peninsula, King George Island, maritime Antarctica. We mapped the occurrence and distribution of plant communities and identified soil–landform–vegetation relationships. The vegetation map was obtained by classification of a QuickBird image, coupled with detailed landform and characterization of 18 soil profiles. The sub-formations were identified and classified, and we also determined the total elemental composition of lichens, mosses and grasses. Plant communities on Potter Peninsula occupy 23% of the ice-free area, at different landscape positions, showing decreasing diversity and biomass from the coastal zone to inland areas where sub-desert conditions prevail. There is a clear dependency between landform and vegetated soils. Soils that have greater moisture or are poorly drained, and with acid to neutral pH, are favourable for moss sub-formations. Saline, organic-matter-rich ornithogenic soils of former penguin rookeries have greater biomass and diversity, with mixed associations of mosses and grasses, while stable felsenmeers and flat rocky cryoplanation surfaces are the preferred sites for Usnea and Himantormia lugubris lichens at the highest surface. Lichens sub-formations cover the largest vegetated area, showing varying associations with mosses.

Soil–landform–plant communities relationships of a periglacial landscape at Potter Peninsula, Maritime Antarctica

Integrated studies on the interplay between soils, periglacial geomorphology and plant communities are crucial for the understanding of climate change effects on terrestrial ecosystems of Maritime Antarctica, one of the most sensitive areas to global warming. Knowledge on physical environmental factors that influence plant communities can greatly benefit studies on monitoring climate change in Maritime Antarctica, where new ice-free areas are being constantly exposed, allowing plant growth and organic carbon inputs. The relationship between topography, plant communities and soils was investigated in Potter Peninsula, King George Island, Maritime Antarctica. We mapped the occurrence and distribution of plant communities and identified soil–landform–vegetation relationships. The vegetation map was obtained by classification of a Quickbird image, coupled with detailed landform and characterization of 18 soil profiles. The sub-formations were identified and classified, and we also determined the total elemental composition of lichens, mosses and grasses. Plant communities at Potter Peninsula occupy 23% of the ice-free area, at different landscape positions, showing decreasing diversity and biomass from the coastal zone to inland areas where sub-desert conditions prevail. There is a clear dependency between landform and vegetated soils. Soils with greater moisture or poorly drained, and acid to neutral pH, are favourable for mosses subformations. Saline, organic-matter rich ornithogenic soils of former penguin rookeries have greater biomass and diversity, with mixed associations of mosses and grasses, while stable felseenmeers and flat rocky cryoplanation surfaces are the preferred sites for Usnea and Himantormia lugubris lichens, at the highest surface. Lichens subformations cover the largest vegetated area, showing varying associations with mosses.