Dinoflagellate cyst distribution in surface sediments of Ambon Bay (eastern Indonesia): Environmental conditions and harmful blooms

Sem Likumahua,Francesca Sangiorgi,M Karin De Boer,Willem M Tatipatta,Daniel D Pelasula,Dominggus Polnaya,Jance Hehuwat,Donna M Siahaya,Anita G.J Buma

doi:10.1016/j.marpolbul.2021.112269

Sem Likumahua, Francesca Sangiorgi + Show 7 more

Open Access

https://doi.org/10.1016/j.marpolbul.2021.112269

Copy DOI

Abstract

The present study aimed to document dinocyst ecological preferences in Ambon Bay, Eastern Indonesia, and to investigate if the bay sediments serve as a seedbank for toxic bloom events. To this end, dinocyst and geochemical analyses of surface sediment samples were performed, along with physicochemical water column parameters. Twentythree dinocyst species were identified, and high dinocyst concentrations (up to ~12,000 cysts g−1 dry sediment) were found in the inner bay. Environmental factors such as surface water temperature and salinity generally played an important role in dinocyst distribution. The concentration of Polysphaeridium zoharyi cysts showed a strong positive correlation with phosphorus. A statistically significant correlation was also found with the concentration of other autotrophic dinocysts in the sediments, and an inverse correlation was observed with the sediment C/N ratio. Cysts may serve as seedbanks for Pyrodinium bahamense blooms in the area.

Highlights

Dinoflagellates are a group of aquatic eukaryotic organisms that play an important role in the marine realm as primary and secondary producers
The concentration in the outer bay ranged between 425 cysts g− 1 DW and 1433 cysts g− 1 DW, of which the highest was at station 8
High abundances of P. zoharyi were found at stations in the inner bay, of which the highest concen tration was detected at station 4 (5975 cysts g− 1 DW) (Fig. 4B and Table 2)

Summary

Introduction

Dinoflagellates are a group of aquatic eukaryotic organisms that play an important role in the marine realm as primary (phototrophic/auto trophic ones) and secondary (heterotrophic ones) producers. Harmful representatives of this taxo nomic group are subject to many studies focusing on their ecology, toxicology, and their complex life cycles (Bravo and Figueroa, 2014). Based on modern surface sediment studies, approximately 15% of the roughly 2000 marine dinoflagellate species are known to produce organic-walled resting cysts, hereafter referred to as dinocysts (Head, 1996; Matsuoka et al, 2013; Bravo and Figueroa, 2014), which are produced mostly after sexual reproduction. Studies of modern dinocysts are useful to trace present and predict future (toxic) bloom events of a certain species in a particular area. Cysts provide insight in the ecology, biogeography, taxonomy and phylogeny of living species (Aydin and Uzar, 2014)

Methods

Results

Discussion

Conclusion