INVESTIGADORES
MONFERRAN Magdalena Victoria
congresos y reuniones científicas
Título:
Identification of anthropic impact on the food web using carbon and nitrogen stable isotopes as chemical markers. Case study:
Autor/es:
JULIETA GRIBOFF; MICHA HORACEK; DANIEL WUNDERLIN; MAGDALENA MONFERRAN
Lugar:
Insbruck
Reunión:
Encuentro; 13th Austrian stable isotope user group meeting (SINA); 2014
Resumen:
Stable isotopes have been used to trace the
impact of anthropic activities, mainly untreated sewage discharges, in three reservoirs
presenting different degrees of eutrophication. The main goal of our research
was finding chemical-isotopic markers that could be used to link anthropic
pollution with changes in different compartments in reservoirs, namely water,
sediment, and different levels of the food web (plankton, shrimps and fish).Thus,
we measured ¦Ä13C and ¦Ä15N
values in various organisms (from primary producers to upper consumers) to
understand the influence of the different anthropogenic activities on the
environment and the possibility to distinguish regions with different types of
contamination, as well as areas of greater or lesser risk for food production.
Study site samplings were carried out during the wet season (April 2014),
after a massive rain event in three lakes
in C¨®rdoba, Argentina: San Roque, Los Molinos and R¨ªo Tercero lakes. San Roque Lake supplies drinking water to C¨®rdoba city, and is also
intended for recreational use. It is surrounded by cities and settlements which
are not fully connected to the public sewage system. Los Molinos
Lake provides water to the Southeastern area of the
city of C¨®rdoba and is used for recreational activities and irrigation.
In the surrounding agriculture, mainly corn and sorghum are produced. R¨ªo Tercero
Lake is the largest artificial reservoir in the province of C¨®rdoba, and it is used
for water supply and industrial activities, as well as for providing cooling
water for a nuclear power plant. We collected water, sediment, plankton, shrimp (Palaemonetes
argentinus) and fish (Odontesthes bonariensis) from each lake. Stable isotope analyses were performed
in an Isotope Ratio Mass Spectrometer (IRMS), connected with an elemental
analyzer (both Thermo Fisher Scientific). Results
showed distinctive patterns in ¦Ä13C and ¦Ä15N between the
lakes under study, allowing the identification of lakes more exposed to anthropogenic
sewage. San Roque Lake showed the highest ¦Ä15N values for
all the samples, indicating the most prominent influence of sewage on the lake
ecology. Further research studies are being conducted to confirm this
preliminary result, providing an interesting alternative to link sewage
discharges with levels of stable isotopes in biota, including edible fish;
thus, pointing out risk for people drinking water or eating fish from such
impacted lakes.