Benthic algal community structures in a bivalent eutrophied tidal channel system at the Northern Patagonian Atlantic coast

FRICKE, A.; NARVARTE, M.; KOPPRIO, G.A.; MARTÍNEZ, A.; ALEMANY, D.; GASTALDI, M.; RENDAS, D.; HIDALGO, F; ALBANO, M.; SAR, E.A.; IRIBARNE, O.; LARA, R.J.; PARODI, E.R.; MARTINETTO, P.

Stralsund

Conferencia; 15th Scientific Conference of the Phycology Section of the German Botanical Society; 2014

German Botanical Society

Eutrophication is one of the most severe anthropogenic impacts of coastalhabitats. Benthic algae react sensitively to changes in ambient nutrientconcentrations, which can be observed in algal blooms and an alteration inwhole community structure. A change in the algal communities can affectthe benthic ecosystem and might alter the top-down bottom-up balance.Due to its extended size and the presence of pristine sites close to humanimpacted areas, the Argentinean Patagonian coast provides a uniquepossibility to study and directly compare the potential effect ofanthropogenic activities on the benthic ecosystem. Nevertheless,knowledge of Patagonian benthic algal communities is currently scarce,compared to that of northern latitudes.Aim of the present work is to investigate benthic algal communities at theNorth Patagonian Atlantic coast, in terms of 1) algal succession, 2) speciescomposition, 3) community structure and 4) chemical algal communitycomposition, in relation to different environmental conditions.Three manipulative multifactorial field experiments were conducted duringspring and autumn 2012/13 at the study site at San Antonio Bay(S40 43 W64 56). In October 2012 a total of 42 experimental units wereexposed in the subtidal of the SAO channel for a period of three weeks,testing the interactive effect of nutrient enrichment (3 levels) on early andlate successional communities. In March 2013 a total of 30 experimentalunits were exposed in parallel at a pristine and a polluted site for a periodof two weeks, to test the interactive effect of nutrient enrichment (3 levels)on naturally grown and site-cross transplanted communities. In parallel thenatural succession was followed at a pristine and a polluted site over aperiod of 357 days.Results of the present study give a first and deep insight into the diversityand complexity of benthic algal communities of the area. Findings of thisstudy provide valuable information which can be used as a baseline forfurther studies investigating potential anthropogenic impact and asecological indicators to improve coastal zone management.