Change in N and P concentrations in Antarctic streams as a response to change in penguin populations

This study presents changes in the concentrations of nitrogen and phosphorus in two streams in Western Antarctica (Admiralty Bay, King George Island, South Shetlands) that differ in trophic status. The results suggest a decline in concentrations of the determined forms of N and P between 2001 and 2005. The decrease ranged from 9.3% for reactive phosphorus to 73.2% for ammonium-nitrogen. Such inferred declines in N and P concentrations are considered to reflect reduced deposition on land of organic matter brought in from the seas by the penguins nesting in the area. The ultimate cause of this is in turn the steady decline in abundance that is being noted for these penguins

Production and Biomass of Seaweeds in Newly Ice-Free Areas: Implications for Coastal Processes in a Changing Antarctic Environment

The Antarctic rocky coasts are mainly colonized by extensive seaweed communities, which play key roles as food resource, habitat, and refuge for many benthic and pelagic organisms. Due to climate warming, Antarctic marine ecosystems are being affected by glacier retreat opening new habitats, e.g., newly ice-free areas that can be colonized by macroalgae. As a consequence, primary production and fate of macroalgae are changing in these new polar environments. In these ecosystems,the carbon production, especially from large brown algae, is an important food source to the benthic invertebrate communities mainly when other resources are scarce. Thus, in new areas colonized by seaweeds, the trophic structure and biogeochemical fluxes can vary considerably. Moreover, when seaweeds die or are removed by water movement, ice scouring, or storms, they are detached, fragmented,and degraded, incorporating and releasing particulate and dissolved organic matter to the coastal food webs, i.e., they support a large fraction of the secondary production of the benthos. The present chapter is a review of the knowledge on seaweed biomass and production in the coastal Antarctic ecosystem opening a discussion on the role of these organisms as main energy sources in, e.g., small fjords and glacier-influenced sites, impacted by recent climatic change.Fil: Quartino, Maria Liliana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Saravia, Leonardo Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de General Sarmiento. Instituto de Ciencias; ArgentinaFil: Campana, Gabriela Laura. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Deregibus, Dolores. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Matua, Carolina V.. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Boraso, Alicia Lilian. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Momo, Fernando Roberto. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentin