A glimpse to Laguna de los Cisnes, a field laboratory and natural monument in the Chilean Patagonia (original) (raw)
Related papers
Oceanography of the Chilean Patagonia
Continental Shelf Research, 2011
Chilean Patagonia is one of the most extended fjord regions in the world that covers nearly 240,000 km2 with an extremely complex coastline and topography in one of the least densely populated areas of the country (1–8 inhabitants every 10 km2). In recent years, the area has been undergoing somewhat intense pressure since several commercial projects in hydroelectricity, tourism, and commercial salmon and mytilid cultures have been developed, or are in progress. Concomitantly, several large research programs have been devised to study the physical, chemical, and biological environment of Patagonia, such as the CIMAR FIORDO, and recently COPAS Sur-Austral based at Universidad de Concepcion, that attempts to close the bridge between oceanographic knowledge and its use by society.In this introductory article we summarize the collection of papers comprising this Special Issue of Continental Shelf Research. These papers deal with aspects of regional oceanography and geology, inorganic and organic geochemistry, ecology of pelagic and benthic organisms, and past changes in productivity.►Chilean Patagonia is an extended fjord region covering ca. 240,000 km2 with a low population density (1–8 inhabitants per 10 km2). ►The fjord area is under intense pressure for industrial development that will impact landscape and natural resources. ►We summarize the most recent collection of research papers on the Chilean Patagonia that deal with regional oceanography and geology, inorganic and organic geochemistry, ecology of pelagic and benthic organisms, and past changes in productivity.
Heterogeneity of fresh-water Patagonia ecosystems
Ecologia Austral
The wide diversity of Patagonian freshwater ecosystems may be classified into three groups: glacial Andean lakes, Extra-andine closed depressions, and rivers and man-made lakes. We here analysed the biotic structure of Patagonian lentic and lotic ecosystems. We focus on the effect of both abiotic (climate, water composition, etc.) and biotic factors (competition, predation) on species diversity and composition of these communities. Zooplankton (rotifers and copepods) and macrobenthic insects (Plecoptera) were chosen as examples of the distribution patterns observed in lakes and rivers respectively. Rotifer species richness was explained by altitude, while species composition was related with conductivity. Three different rotifer assemblages were identified and associated with particular ranges of conductivity. In addition, the distribution of two rotifer genera, Keratella and Asplanchna, was related with biotic interactions (competition and predation). Crustacean size spectrum depended on visual fish predation. Plecoptera species richness decreased as a function of the stream order. Low stream order covered by Nothofagus forest showed the highest species number.
Plankton crustaceans in bays with different trophic status in Llanquihue lake (41° S Chile)
Brazilian Journal of Biology, 2017
The Llanquihue lake is included in the called Araucanian or Nord Patagonian lakes located between 38-41° S. These lakes are characterized by their oligo-mesotrophic status due to human intervention which takes to the increase in nutrients inputs from industries and towns. Effects on zooplankton assemblages are observed with marked increase of daphnids abundance. The aim of the present study is to analyze the trophic status and zooplankton relative abundance in different bays of Llanquihue lake. It was found direct associations between chlorophyll a with daphnids percentage, total dissolved nitrogen with reactive soluble phosphorus nitrogen/phosphorus molar radio with cyclopoids percentage, and an inverse relation between daphnids and calanoids percentages. The occurrence of three kinds of microcrustacean assemblages and environmental conditions was evidenced: the first one with high calanoids percentage, low species number and low chlorophyll and nutrients concentration, a second wi...
Environmental Monitoring and Assessment, 2013
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Plankton and hydrochemistry of Lake Futalaufquen (Patagonia, Argentina) during the growing season
Hydrobiologia, 1995
Plankton communities and hydrochemistry of an oligotrophic lake occupying a glacial valley in Argentinian Patagonia (42 °49'S ; 71 °43'W) were studied. Monthly samples at three stations integrated from 0 to 50 m and stratified samples at the site of maximum depth, were taken during the growing season. Transparency was always controlled by glacial silt, and not by phytoplankton. Lake water belongs to the calcium-bicarbonate type, with low conductivity (24 1tS cm-1), and poor buffering capacity. Forty-five phytoplankton taxa were found. Mean phytoplankton density was 49 cells ml-1 and mean biomass 69 Mg 1-1. N :P relationships, inorganic nitrogen exhaustion in the photic layer, and correlations between nutrients and phytoplankton density suggests nitrogen as the main limiting factor. Fifteen zooplankton species were found. Mean zooplankton density was 12 .2 ind. 1-1 and mean biomass 22 .9 ug 1-1. Diatoms and Boeckellidae were the dominant planktonic groups. Morphometry and hydrological factors were responsible for horizontal heterogeneity in phytoplankton and chemical variables. 63 Futalaufquen Lake. Altitude 518 m a.s .l. Surface area 44 .6 km2 Mean depth * 101 m Maximum depth * 168 m Volume * 4509 km3 Total watershed area 2920 km2
Progress in Oceanography, 2007
We compared the signals of several water column properties (upwelling intensity, sea level anomaly, temperature, nutrients, dissolved oxygen, chlorophyll-a, and surface sediments) of the continental shelf off Concepció n (36°S) during the 1997-1998 El Niñ o with those of a normal year (2002)(2003). We found that the primary hydrographic effect of El Niñ o 1997-1998 was a reduction in the input of nutrient-rich, oxygen-poor Equatorial Subsurface Water over the shelf. This affected the biology of the water column, as evidenced by the reduced phytoplankton biomass. Surface sediment properties (biogenic opal, organic carbon, bulk d 15 N) observed during El Niñ o 1997-1998 reflected a reduced export production and the sediments failed to show the water column seasonality that occurs under normal conditions. In addition, weakened denitrification and/or upper water column fertilization could be inferred from the sedimentary d 15 N. Although diminished, export production was preserved in the surface sediments, revealing less degraded organic matter in the upwelling period of the El Niñ o year than in the normal year. We suggest that the fresher organic material on the seafloor was probably associated with a severe reduction in the polychaete Parapronospio pinnata, which is considered to be the most important metazoan remineralizer of organic carbon at the sediment-water interface in the study area.
Evidence of the Anthropic Impact on a Crustacean Zooplankton Community in Two North Patagonian Lakes
Sustainability
Lately, agriculture, livestock, forestry, and aquaculture activities have been greatly developed in Chilean North Patagonia, negatively impacting the balance of the environmental conditions in lakes and affecting the development and survival of several native species. The aim of this study was to assess the anthropic impact on a zooplankton community in two North Patagonian lakes. We collected samples from four sites belonging to Lake Icalma and Lake Llanquihue, including four replicates per site. Water samples were analyzed for physicochemical characteristics and zooplankton communities. We focused on the presence of Daphnia pulex, a species of zooplanktonic crustacean that performs a key role in capturing energy from primary producers to deliver it to final consumers such as fish. We found that Llanquihue showed higher total phosphorus, nitrogen, copper, iron, manganese, total dissolved solids (TDS), and conductivity (EC) than Icalma. Furthermore, ecological variables were greatly...
Biogeosciences Discussions, 2012
We assessed temporal variability in phytoplankton biomass, Chlorophyll a, nutrient availability, Gross Primary Production (GPP), community respiration (CR), and bacterial secondary production (BSP) over a year of monthly observations (October 2007 to October 2008) at a fixed station in the Puyuhuapi fjord, Chilean Patagonia (44 • S, 73 • W). A set of in situ observations gathered over two consecutive spring-summer seasons, and one autumn-winter season in the middle, has made it possible to connect the two-phase (i.e. productive season/non-productive season) pattern of Chlorophyll a (Chl a) variability shown by satellite data with a two-phase cycle in GPP, CR, and the composition of phytoplankton assemblages. Estimates of annual GPP and CR, integrated over the top 20 meters of the water column, were 533 and 537 g C m −2 yr −1 , respectively. Low values of pCO 2 were measured in mixed layer autotrophic waters (GPP/CR > 1) while high pCO 2 levels were measured in mixed layer heterotrophic waters (GPP/CR < 1). Bacterial Secondary Production (BSP) was significantly and positively correlated with GPP (r = 0.6, p < 0.05, n = 24) and Chl a (r = 0.4, p < 0.05, n = 24) on an annual cycle basis. The winter drop in bacterioplankton (both bacteria and archea) activity (from 0.9 ± 0.6 g C m −2 d −1 to 0.6 ± 0.3 g C m −2 d −1) was not as pronounced as the winter drop in phytoplankton activity (from 1.1 ± 1.12 g C m −2 d −1 to 0.1 ± 0.09 g C m −2 d −1). It is hypothesized that dissolved organic matter (DOM) of terrestrial origin plays an important role (especially in winter) supporting bacterial activity in the Puyuhuapi fjord.