Assessing the Contribution of Posidonia oceanica to Mediterranean Secondary Production Through Stable Isotope Analysis

Abstract

The role of seagrasses in providing a complex habitat for marine organisms is globally documented; however, few studies have investigated the trophic incorporation of endemic Mediterranean Posidonia oceanica into marine food webs. Meadows of P. oceanica are declining due to climate change and anthropogenic pressures, emphasising the need to determine its contribution in local trophic dynamics. We investigated whether benthic marine invertebrate (BMI) and fish consumers assimilate carbon directly from P. oceanica seagrass or other sources along the seagrass meadow margins in Malta. We sampled and analysed the δ13C and δ15N isotope values of P. oceanica, particulate organic matter (POM), macroalgae, 14 invertebrate taxa, and 10 fishes at three locations marginal to P. oceanica seagrass meadows. Stable isotope ratios were significantly different between all taxa (F26 = 17.37, R2 = 0.68, p

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