Algal Community Membership of Estuarine Mudflats from the Savannah River, United States

Kalina Manoylov,Yenkang France,Joseph Dominy,Abeselom Geletu

doi:10.3390/jmse4010011

Abstract

Algae represent a large and diverse group of photosynthetic organisms inhabiting all aquatic habitats. Although the traditional assessment of algal diversity relies mainly on microscopy-based morphological identification, certain limitations exist. In this study, we present a combined molecular and morphological assessment of algal diversity in mudflats from the Savannah River Estuary, Georgia. High diversity of diatoms was documented, and less than 20% of the algal community was physiologically active at the time of collection. From the total genomic DNA extracted from the field samples and lab isolates, 18S rDNA sequences were PCR amplified, cloned, sequenced, identified, and then compared to the taxa identified via microscopy. Only a few of the DNA sequences matched documented taxa, and the abundance of particular algal species was limited to morphological analysis. Surprisingly, upon examination of the remaining lysis buffer from the mechanical lysis step of algal cells, diatom species were left intact even in the presence of a detergent indicating that the diatom species resistant to lysis could be easily underrepresented. Generation of additional algal sequences data, tied to accurate taxonomic identification, is essential to current environmental sequencing projects and potentially would allow faster acquisition of algal community structure within these unique environments.

Highlights

Estuaries can be defined as partially enclosed bodies of coastal water with a free connection to the open sea, within which seawater is diluted by a freshwater system [1]
From the whole algal community enumeration, less than 20% of the observed algae were alive at the time of collection
As a result of this research, we identified, for the first time, all algal groups inhabiting the mudflats of the Savannah River and found that diatoms dominated the community

Summary

Introduction

Estuaries can be defined as partially enclosed bodies of coastal water with a free connection to the open sea, within which seawater is diluted by a freshwater system [1]. These areas contain varying amounts of salinity and nutrients dependent upon tidal changes and upstream runoff. Disturbances include red tides, fish kills, marine mammal deaths, shellfish poisoning, hypoxia, and anoxia [2,3]. Often times, these events are preceded by changes in algal species composition. The importance for studying primary producers from these dynamic ecosystems may provide answers for prevention of large-scale disturbance within those ecologically important habitats

Objectives

Results

Conclusion