1. Explosive volcanic submarine activity is expected to affect seagrass communities due to suddenand dramatic changes in the physical and chemical features of sea water and sediments, with possiblylarge ecosystem effects. However, seagrass response to the harsh environmental conditions thatarise due to explosive volcanism is as yet unexplored as it is not easy to predict when and where aneruption will occur. Here, we investigate the uptake of hydrothermal carbon within the seagrassPosidonia oceanica by the analysis of d13C and growth rates in tissue laid down before and after anexceptional and massive hydrothermal gas release in the Aeolian Islands (Italy, MediterraneanSea).2. Hydrothermal submarine activity was recorded by P. oceanica, which showed a large and persistent13C-depletion in both scales and rhizomes in the site close to the eruption. Both increased CO2availability and reduced carbon demand, as a consequence of stressful environmental conditions(e.g. light limitation due to turbidity, high temperature), combined to give much lower d13C signatures.Our results suggest that the explosive volcanism caused physiological stress in the seagrass,leading to a reduction in productivity, whereas slower, more diffuse release of hydrothermal CO2 isknown to enhance seagrass productivity.3. Synthesis. We analysed the effect of a sudden and large hydrothermal event on d13C interannualvariations and growth of the seagrass P. oceanica. Our results confirm that shallow submarinehydrothermal vents can be used as natural laboratories for exploring biological responses to acuteand often extreme environmental conditions. P. oceanica can record geological events by capturingCO2 derived from vent systems, with implications for habitat management to mitigate against raisingCO2 levels and ocean acidification. This leads the way to further studies to evaluate the effects ofhydrothermal carbon on shallow ecosystems.
|Numero di pagine||8|
|Rivista||Journal of Ecology|
|Stato di pubblicazione||Published - 2010|
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