Vergleich der Toleranz gegenüber Salinitätsstress bei der einheimischen Bivalviaart Perna perna und der invasiven Bivalviaart Isognomon bicolor in dem Bundesstaat Rio de Janeiro in Brasilien.

Mummelthei, Corinna (2010) Vergleich der Toleranz gegenüber Salinitätsstress bei der einheimischen Bivalviaart Perna perna und der invasiven Bivalviaart Isognomon bicolor in dem Bundesstaat Rio de Janeiro in Brasilien. (Diploma thesis), Albert-Ludwigs Universität , Freiburg, Germany, 96 pp.

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Abstract

Bioinvasions are becoming more frequent in coastal habitats. Another process that affects coastal habitats is an increase in frequency and intensity of extreme weather
events, e.g. heavy precipitation and droughts that are predicted with climate change. In the face of climate change it can be questioned if native or invasive marine species cope better with abiotic stress. For an experimental study marine bivalves were collected at
the coast of Rio de Janeiro state in Brazil. The species studied were the bivalves Perna perna and Isognomon bicolor. P. perna is an important ecological engineer and the dominant native species in benthic communities at Brazilian´s coastline. The invasive species I. bicolor, coming from the Carribean, first established in Brazil around the 1970's or 80's, became very abundant explosively in the 90's and started to outcompete native species.
This study applied short- and long-term salinity stress to P. perna and I. bicolor to compare their stress response. The response variables measured were oxygen
consumption, Byssus thread production and mortality. Byssus thread production showed that salinity stress affected the two bivalves. The strength of salinity stress was reflected
in the occurrence of Byssus thread production. Exposure to 5 PSU showed a significant effect on the oxygen consumption of the two bivalves. Both species lowered their oxygen consumption under stress. At the second day of stress, oxygen comsumption of I. bicolor was 25 % less than the oxygen consumption of P. perna. Furthermore the oxygen-uptake of P. perna fluctuated in the post stress phase, whereas such fluctuation was not found in I. bicolor. This suggested that P. perna needed more time after stress
to get back to its initial state of respiration. Under stress, mortality was more common in P. perna than in I. bicolor. This occurred under a hyposalinity of 5 PSU and 20 PSU as well as under a hypersalinity of 65 PSU. Results of the experiments suggest that the invasive species I. bicolor copes better with salinity stress than the native species P. perna.
If invasive species generally have higher stress tolerance against abiotic stress, climate change may influence competitive hierarchies in benthic communities by favouring
invaders.

Document Type: Thesis (Diploma thesis)
Thesis Advisors: UNSPECIFIED
Additional Information: Betreuer: Prof. Dr. Gerhard Bauer, Dr. Mark Lenz, Prof. Dr. Bernardo da Gama
Keywords: Benthic Ecology; GAME; bioinvasion; coastal ecosystem; Perna perna; Isognomon bicolor
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EOE-B Experimental Ecology - Benthic Ecology
Open Access Journal?: No
Projects: GAME
Date Deposited: 05 Sep 2011 08:36
Last Modified: 06 Jul 2012 14:59
URI: http://oceanrep.geomar.de/id/eprint/12086

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