February 1st to 5th 2016
Olhão, Portugal
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Physiological resilience of southern edge populations of Fucus vesiculosus to consecutive desiccation and heat shock

Scientific Exhibition
Future Oceans
Wednesday, February 3, 2016 -
18:30 to 20:00

Martins, N. 1 Serrão, E.A. 2 Pearson, G.A. 3

1Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
2Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
3Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal

Intertidal communities are particularly sensitive to climatic stress, since they are exposed to a wide range of adverse environmental fluctuations, especially towards their southern distribution limits. In previous work our group examined how microhabitat thermal conditions relate to physiological limits in a recently extinct southern edge population of the intertidal alga Fucus vesiculosus. The authors suggested that desiccation may function as a protective strategy by maintaining algal tissues in a metabolically inactive state during peak stress periods [1]. Although several studies focused on intertidal algal responses to environmental stress, little is known about their responses to the repeated adverse conditions to which they are exposed in the field. In this study we evaluated the physiological resilience of southern edge populations of F. vesiculosus to 3 consecutive cycles of heat shock or desiccation. Apices of this species were acclimated for approximately 1 week immersed at 15ºC under a 12 h day photoperiod (50-100 ?mol m-2 s-1). The assays were carried out by exposing acclimated apices to heat shock or desiccation at 25 and 35ºC for 5 h. Controls were manipulated as stress treatments at 15ºC. Physiological responses were determined by measuring maximum photosynthetic efficiency (Fv/Fm) after the stress treatment and following a 2 and 19 h recovery period under acclimation conditions. Overall, F. vesiculosus can withstand higher levels of thermal stress when aerially exposed than when immersed. Consecutive exposure to thermal stress led to cumulative loss of resilience, as algae failed to fully recover from the damage caused by previous exposures.[1] Mota CF et al. (2014) Functional Ecology doi: 10.1111/1365-2435.12373
keywords: 
intertidal stress, desiccation, heat shock, range edge populations, Fucus vesiculosus

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