Diatoms, protein and carbohydrate sediment content as proxies for coastal eutrophication in Montevideo, Rio de la Plata Estuary, Uruguay

  • Felipe Garcia-Rodriguez Universidad de la República; Facultad de Ciencias; Seccion Oceanologia
  • Laura del Puerto Universidad de la República; Sede Rocha; Centro Universitario Regional Este
  • Natalia Venturini Universidad de la República; Facultad de Ciencias; Seccion Oceanologia
  • Ana Laura Pita Universidad de la República; Facultad de Ciencias; Seccion Oceanologia
  • Ernesto Brugnoli Universidad de la República; Facultad de Ciencias; Seccion Oceanologia
  • Leticia Burone Universidad de la República; Facultad de Ciencias; Seccion Oceanologia
  • Pablo Muniz Universidad de la República; Facultad de Ciencias; Seccion Oceanologia
Keywords: Diatoms, Carbohydrates, Proteins, Estuaries, Coastal eutrophication, Uruguay

Abstract

A study on sediment surface diatom composition in relation to both protein/carbohydrate content and salinity was carried out in Montevideo Bay and the adjacent coastal zone. Samples were seasonally taken during one year along a human impact gradient, and the trophic conditions were assessed from the biochemical composition of the surface sediment organic matter. The co-occurrence of the marine-brackish (Actinocyclus curvatulus, Actinocyclus gallicus, Coscinodiscus excentricus, Coscinodiscus radiatus, Hyalodiscus subtilis, Paralia sulcata) and freshwater diatom flora (Aulacoseira granulata, Aulacoseira italica, Aulacoseira muzzanensis, Actinocyclus normanii, Amphora copulata, Cyclotella meneghiniana, Nitzschia linearis), suggests myxohaline estuarine conditions in the study area. The sampling stations located within the bay, close to several contamination sources, exhibited hypertrophic conditions as indicated by the highest levels of protein content, but also by the high relative abundances of Actinocyclus normanii and Cyclotella meneghiniana, as both diatom species are very well established cosmopolitan proxies of aquatic degradation. The levels of both protein and carbohydrate content, but also photosynthetic pigments, recorded in the adjacent coastal zone suggest meso-eutrophic conditions as contamination levels from the inner bay might become diluted off shore. Multivariate diatom species-environmental data relationships, indicate that the trophic gradient is hierarchically more important than salinity in explaining the diatom distribution. The present data imply an improvement in our ability of assessing organic contamination in the study area, since both biological and biopolymer variables were introduced for the first time as a tool for assessing the benthic health/degradation in one of the most populated regions of the Río de la Plata.

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Published
2011-12-01
How to Cite
Garcia-Rodriguez, F., Puerto, L., Venturini, N., Pita, A., Brugnoli, E., Burone, L., & Muniz, P. (2011). Diatoms, protein and carbohydrate sediment content as proxies for coastal eutrophication in Montevideo, Rio de la Plata Estuary, Uruguay. Brazilian Journal of Oceanography, 59(4), 293-310. https://doi.org/10.1590/S1679-87592011000400001
Section
naodefinida