Patterns in Alpha and Beta Phytoplankton Diversity along a Conductivity Gradient in Coastal Mediterranean Lagoons

Evangelia Michaloudi,Maria Moustaka-Gouni,Matina Katsiapi,Maria Demertzioglou,Dimitris Tsianis,Natassa Stefanidou

doi:10.3390/d12010038

Evangelia Michaloudi, Maria Moustaka-Gouni + Show 4 more

Open Access

https://doi.org/10.3390/d12010038

Copy DOI

Abstract

Understanding the diversity patterns of phytoplankton assemblages in coastal lagoons is clearly important for water management. In this study, we explored alpha and beta diversity patterns in phytoplankton communities across five Mediterranean lagoons hydrologically connected to Vistonikos Gulf. We examined the phytoplankton community composition and biomass on a monthly basis from November 2018 to October 2019. For this, water samples were collected from seven inshore, brackish and coastal waters, sampling sites covering a wide range of conductivity. We found significant spatial and temporal differences in phytoplankton alpha diversity and in phytoplankton biomass metrics explained by the high variation of conductivity. Evenness remained low throughout the study period, reflecting significant dominance of several phytoplankton blooms. Harmful algal blooms of Prorocentrum minimum, Alexandrium sp., Rhizosolenia setigera and Cylindrotheca closterium occurred. The system’s species pool was characterized by relatively high phytoplankton beta diversity (average ~0.7) resulting from high temporal species turnover (90%). Overall, alpha and beta diversity components were indicative of rather heterogeneous phytoplankton communities which were associated with the high differences in conductivity among the sampling sites.

Highlights

Coastal lagoons are shallow semi-enclosed dynamic ecosystems which are connected to the sea by one or more restricted inlets [1]
In addition to human exploitation, coastal lagoons have been identified as one of the most vulnerable habitants to potential impacts associated with climate change [5,9]
We explored the degree of homogeneity across the different waterbodies by computing beta diversity

Summary

Introduction

Coastal lagoons are shallow semi-enclosed dynamic ecosystems which are connected to the sea by one or more restricted inlets [1]. They are transitional zones between the terrestrial and the marine environment occupying 13% of the coastal areas worldwide [2]. Coastal lagoons provide essential ecosystem services [3]. Due to their shallow depth and the restricted water exchange with the adjacent sea, they are naturally high productive ecosystems [4,5] that are usually subjected to intensive human activities, mostly aquaculture, with several consequences [6,7,8]. Projections for atmospheric temperature increase up to 6 ◦ C in parallel with the more often and stronger hot extremes for the Mediterranean region [10,11] would most probably increase the salinity in coastal lagoons affecting, in turn, the biological communities

Objectives

Methods

Results

Discussion

Conclusion