Bacterial composition of sponges, sediment and seawater in enclosed and open marine lakes in Ha Long Bay Vietnam

ABSTRACT

Marine lakes are landlocked bodies of seawater, isolated to varying degrees from the surrounding marine habitat. Isolated lakes generally have lower pH values, salinities and higher temperatures than more open lakes. We used a 16S rRNA gene barcoded pyrosequencing approach to study the bacterial communities of two sponge species, sediment and seawater in one enclosed and two open marine lakes. Bacterial communities of the sponge Spheciospongia solida mainly consisted of Proteobacteria, Cyanobacteria and Bacteroidetes. In contrast, Proteobacteria, Chloroflexi and Acidobacteria dominated the bacterial communities of the sponge Spongia ceylonensis. Although only a limited amount of samples were collected, both water and S. ceylonensis sponge had higher relative abundances of Cyanobacteria in the enclosed lake, which mainly consisted of OTUs assigned to the genus Synechococcus. This is in line with a number of previous studies, which have shown that environmental conditions found within low pH environments such as marine lakes benefit the growth of Synechococcus spp. Future studies should address the mechanism by which Synechococcus spp. may help host sponges and their bacterial communities adapt to low pH conditions in isolated marine lakes and other low-pH environments.

KEYWORDS:

• Bacteria
• composition
• Marine lakes
• Vietnam

Acknowledgements

This work is a contribution to the projects LESS CORAL, PTDC/AAC-AMB/115304/2009 and Ecotech-Sponge (PTDC/BIAMIC/6473/2014 – POCI-01-0145-FEDER-016531) funded by FEDER, through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI), and by national funds (OE), through FCT/MCTES. Thanks are due, for the financial support to CESAM (UID/AMB/50017/2019), to FCT/MEC through national funds, and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. Marina R. S. Ferreira (Ph.D. scholarship: SFRH/BD/114809/2016) and Ana R.M. Polónia (postdoctoral scholarship: SFRH/BPD/117563/2016) were supported by scholarships funded by FCT, Portugal subsidised by National funds MCTES. We are grateful to students and colleagues from the Department of Marine Biodiversity and Conservation, Research Institute for Marine Fisheries in Vietnam that assisted in the field.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Daniel Francis Richard Cleary http://orcid.org/0000-0002-6143-3390

Marina R. S. Ferreira http://orcid.org/0000-0003-0470-9677

Ana Rita Moura Polónia http://orcid.org/0000-0003-3381-7677

Newton Carlos Marcial Gomes http://orcid.org/0000-0003-1934-0091

Nicole Joy de Voogd http://orcid.org/0000-0002-7985-5604

Additional information

Funding

This work was supported by Fundação para a Ciência e a Tecnologia [Grant Number PTDC/AAC-AMB/115304/2009, PTDC/BIAMIC/6473/2014-POCI-01-0145-FEDER-016531,UID/AMB/50017/2019, SFRH/BD/114809/2016, SFRH/BPD/117563/2016].