Temperature Dependence of Oxygen Dynamics and Comm

Authors: Raquel VaquerSunyer Carlos M Duarte Gabriel Jordà Sergio RuizHalpern

Publish Date: 2012/05/30

Volume: 35, Issue: 5, Pages: 1182-1192

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Abstract

Hypoxia is emerging as a major threat to marine coastal biota Predicting its occurrence and elucidating the driving factors are essential to set successful management targets to avoid its occurrence This study aims to elucidate the effects of warming on the likelihood of hypoxia Highfrequency dissolved oxygen measurements have been used to estimate gross primary production GPP net ecosystem production NEP and community respiration CR in a shallow macroalgae Caulerpa prolifera ecosystem in a highly humaninfluenced closed Mediterranean bay Daily averaged GPP and CR ranged from 0 to 12409 and 514 to 12973 mmol O2 m−2 day−1 respectively The higher GPP and CR were calculated for the same day when daily averaged water temperature was 283 °C and resulted in a negative NEP of −564 mmol O2 m−2 day−1 The ecosystem was net heterotrophic during the studied period probably subsidized by allochthonous organic inputs from ground waters and from the surrounding town and boating activity Oxygen dynamics and metabolic rates strongly depend on water temperature with lower oxygen content at higher temperatures The probability of hypoxic conditions increased at a rate of 039  °C−1 ±014  °C−1 Global warming will increase the likelihood of hypoxia in the bay studied as well as in other semienclosed baysThis research is a contribution to the “Water bodies in Europe Integrative Systems to assess Ecological Status and Recovery WISER” project funded by FP7 contract 226273 the project MEDEICG funded by the Spanish Ministry of Science and Innovation number CTM200907013 and the project MARINERA funded by the Spanish Government Ref CTM200804183E/MAR R VaquerSunyer was funded by the WISER project G Jordà acknowledges a JAEDOC contract funded by the Spanish research council CSIC We thank R Martínez L Royo M Noguera and A Steckbauer for help on sampling and JC Alonso for nutrient analysis We want to thank JJ Coloso for his generosity in sharing his MATLAB program with us

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