The influence of riverine input on marine meiobenthic copepods

SCIBERRAS, MICHEL; DI ROSSI, CATALINA

Congreso; International Conference on Copepoda e-ICOC 2022; 2022

World Association of Copepodologists

We performed a study to test the influence of the riverine input on the community of marine miobenthic copepods. We sampled the intertidal region surrounding the mouth of nine rivers in the Buenos Aires Province (Argentina). In each river we took three sediment samples in three different levels: next to the mouth, and 200 m to the north and 200 m to the south on the cost. The sampling was carried out in July (winter), November (spring) and February (summer) to consider the seasonal variability. Using a Structural Equation Modeling we explored the relationship of several environmental variables (temperature, salinity, sediment heterogeneity, organic matter content) with the copepod diversity (Shannon diversity index), regardless the level on the cost. We found a positive relation between the organic matter content and copepod diversity, and beside the content of organic matter was positively influence by the sediment heterogeneity. Since we found that the only variable analysed that had an influence on copepod diversity was the organic matter content, we performed a Genelarized Linear Mixed Model to evaluated the relation between the relative abundance of species in the different levels (mouth, north, south) and the organic matter content. We found a positive relation (significant but with a low slope) between the two variables but we found a strong difference among the abundances in the different levels (mouths had more abundance than north and south sites, and north sites had more abundance than south sites). According to these results, the riverine input has an influence on the diversity of marine meiobenthic copepods. Part of this influence is explained by the organic matter content but there are probably other variables that were not analysed in this study playing and important role.