Havsförsurningens effekter på fiskars hjärnor och beteende
Tidsperiod: 2013-01-01 till 2016-12-31
Budget: 2 400 000 SEK
Ocean CO2 concentration increase in line with atmospheric CO2 resulting in ocean acidification. In addition, rising ocean CO2 concentrations may by itself have severe disturbing effects on fish behaviour. Recent studies have shown that near future CO2 levels, can cause a behavioural reversal in larval fish, significantly reducing settling success. In fish, high pCO2 could lead to a shift in the gradients of Cl- and/or HCO3- across neural membranes, resulting in a reversal of the GABA-A receptor action, i.e. making it excitatory instead of inhibitory. This hypothesis is supported by a recent report that treatment with a GABA-A receptor antagonist counteracts the behavioural effects of elevated pCO2. The effect could be wide spread among marine fish species since GABA-A receptor mechanisms appear conserved. However, the time-course of the behavioural effects of elevated pCO2 suggests that effects on gene expression may be involved. Moreover, it is likely that fresh water fish living shallow eutrophic environments, where pCO2 may fluctuate, display adaptations to high pCO2. The current proposal will apply a comparative approach, comparing marine fish to zebrafish in order to assess behavioural effects of GABA-A receptor ion permeability and subunit composition. This will provide information on the mechanisms behind the behavioural changes, which can subsequently be used to predict the sensitivity of different species to rising ocean CO2 concentrations.