The role of seagrass vegetation and local environmental conditions in shaping benthic bacterial and macroinvertebrate communities in a tropical coastal lagoon.

Abstract
We investigated the influence of seagrass canopies on the benthic biodiversity of bacteria and macroinvertebrates in a Red Sea tropical lagoon. Changes in abundance, number of taxa and assemblage structure were analyzed in response to seagrass densities (low, SLD; high, SHD; seagrasses with algae, SA), and compared with unvegetated sediments. Biological and environmental variables were examined in these four habitats (hereafter called treatments), both in the underlaying sediments and overlaying waters, at three randomly picked locations in March 2017. Differences between treatments were more apparent in the benthic habitat than in the overlaying waters. The presence of vegetation (more than its cover) and changes in sedimentary features (grain size and metals) at local scales influenced the observed biological patterns, particularly for macroinvertebrates. Of note, the highest percentage of exclusive macroinvertebrate taxa (18% of the gamma diversity) was observed in the SHD treatment peaking in the SA for bacteria. Benthic macroinvertebrates and bacteria shared a generally low number of taxa across treatments and locations; approximately, 25% of the gamma diversity was shared among all treatments and locations for macrofauna, dropping to 11% for bacteria. Given the low overlap in the species distribution across the lagoon, sustaining the connectivity among heterogeneous soft sediment habitats appears to be essential for maintaining regional biodiversity. This study addresses a current scientific gap related to the relative contributions of vegetated and unvegetated habitats to biodiversity in tropical regions.

Citation
Alsaffar, Z., Pearman, J. K., Cúrdia, J., Ellis, J., Calleja, M. L., Ruiz-Compean, P., … Carvalho, S. (2020). The role of seagrass vegetation and local environmental conditions in shaping benthic bacterial and macroinvertebrate communities in a tropical coastal lagoon. Scientific Reports, 10(1). doi:10.1038/s41598-020-70318-1

Acknowledgements
The authors would like to thank the boat captains from the Coastal & Marine Resources core laboratory who enabled the sampling to be undertaken. The research reported in this publication was supported by funding from KAUST as well as from collaboration between KAUST and Saudi Aramco within the framework of the Saudi Aramco – KAUST Center for Marine Environmental Observations. We would also like to thank the editor and two reviewers who greatly contributed to improving an earlier version of this manuscript.

Publisher
Springer Nature

Journal
Scientific Reports

DOI
10.1038/s41598-020-70318-1

PubMed ID
32782295

PubMed Central ID
PMC7419567

Additional Links
http://www.nature.com/articles/s41598-020-70318-1

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