Physicochemical variables and biological elements to assess climate change impacts within a north Patagonia estuarine ecosystem (south Atlantic): perspectives after 30 years of data

ARIAS, A.H.; PICCOLO, C.M.; SPETTER, C.V.; FREIJE, R.H.; MARCOVECCHIO, J.H.

Portugal, Figueira da Foz "Centro de Artes e Espectáculos (CAE)"

Congreso; ECSA 47 (Estuarine & Coastal Sciences Association) congress; 2010

Estuarine & Coastal Sciences Association

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-GB;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Climatic change will generate an increase in temperature around the globe, ice melting, a sea level rise, an increase in precipitation in the global mean, among other alterations of the environment. While the expected consequences of climate change are global, the occurrence of extreme events and specific environmental problems are usually local or regional phenomenon. In particular, coastal ecosystems are vulnerable zones to early climate impacts. The Bahia Blanca estuary, Argentina, is located at 38º 40´ S and 62º 09´ W in the north Patagonia, with an area of 2300 km2. Based on more than thirty years historical oceanographic and meteorological data of the Bahia Blanca estuary, an outline of present and future climatic impacts is presented. Water temperature showed -in average- a consistent warming in the last four decades, with an increase in the values of maximum temperature and strong interannual variations. The water pH trend matched the globally observed acidification trend, although it was climatically altered during ENSO events in the present decade. On the other hand, great precipitation variability was found in the study region: during the last two decades, the area presented extreme droughts (i.e., 1995) and extreme precipitation amounts (2001). Long term physical-chemical variability (water temperature, salinity, pH and dissolved oxygen) was linked to observed effects on the ecosystem, namely, phytoplankton and zooplankton community’s changes and commercial crustaceans and fisheries decrement. Finally, following the sea level rise IPCC’s predictions due to water expanding and melting from land-based glaciers and ice caps, a modeled evaluation of potential coastal impacts was approached, showing that the area of study is one of the most vulnerable areas of the North Patagonia coasts: predictive models showed that the extensive intertidal area and all the islands would be covered -reaching an area of about 1463 Km2-, consequently changing the ecosystem functioning and baseline conditions.