Impact of Organic Loads and Environmental Gradients on Microphytobenthos and Meiofaunal Distribution in a Coastal Lagoon

Abstract

The impact of organic loads and environmental gradients on spatial and temporal distribution of microphytobenthos and meiofauna was investigated in the Lesina Lagoon. This system was characterised by high organic matter contents (mostly composed of carbohydrates 60–70%). which decreased from the marine to the continental sector of the lagoon and influenced the meiofaunal distribution and abundance. Both meiofaunal abundance (638–6328 ind. 10 cm⁻²) and microphytobenthos density and biomass (43–1031 × 10³ cells cm⁻³ and 24.43–591.12 μgC cm⁻³, respectively) displayed a wide spatial and temporal variability, more evident for microphytobenthos than for meiofauna. Our study suggests that, in the Lesina lagoon, meiofaunal abundance was reduced by sediment organic matter accumulation, but was not affected by salinity gradients, which conversely influenced microphytobenthos distribution.

Keywords:

• Meiofauna
• Microphytobenthos
• Organic matter
• Lagoon