INVESTIGADORES
VILLAFAÑE virginia Estela
congresos y reuniones científicas
Título:
Impact of UVR and temperature on symbiotic dinoflagellates from tropical coral reef ecosystems
Autor/es:
BANASZAK, A. T.; VILLAFAÑE, V. E.; GUENDULAIN GARCIA, S. D.; LOMBARDO, L.; HELBLING, E. W.
Lugar:
Mar del Plata
Reunión:
Congreso; The Changing Coastal and Estuarine Environment: A Comparative Approach; 2012
Institución organizadora:
Coastal and Estuarine Research Federation
Resumen:
Coral-reef
ecosystems are characterized by exposure to high UVR levels due to the low
solar zenith angles typical of tropical regions as well as the naturally low
ozone concentrations in combination with the high transparency of the overlying
water column. Over geological time, UVR has been a strong selective pressure
for coral-reef dwelling organisms to adapt photoprotective and repair
mechanisms to cope with this stressor. Over the last few decades, a new
stressor, rising sea surface temperature, has been increasingly documented in
coral reef environments and implicated in coral bleaching events. Coral
bleaching is defined as the breakdown of the relationship between the coral
host and its photosynthetic dinoflagellate symbionts belonging to the genus Symbiodinium such that the coral tissue
becomes pale. In extreme cases, bleaching events can lead to widespread mass
mortality of corals. The combination of high UVR levels and increased temperature
may have important effects on corals and their symbionts. Here we describe a
series of experiments that were undertaken with various genetic types (clades)
of Symbiodinium using both artificial
and natural solar radiation where UVR and PAR (photosynthetically active
radiation) were varied in combination with ambient and increased temperatures.
Our results suggest that the various Symbiodinium
clades that were tested have widely different responses to UVR and temperature
in terms of the quantum yield of photosystem II (PSII) fluorescence as well as
their inhibition and recovery rates. Our data demonstrate that the variety of
responses is due to differences in the photoprotective and non-photochemical
quenching mechanisms characteristic of each clade