Inhibition of invertebrate larval settlement by biofilm ciliates

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 557:77-90 (2016) - DOI: https://doi.org/10.3354/meps11825 Inhibition of invertebrate larval settlement by biofilm ciliates Matthew G. Watson1,*, Andrew J. Scardino2, Liliana Zalizniak1, Jeff Shimeta1 1Centre for Environmental Sustainability and Remediation, School of Science, RMIT University, Bundoora, Victoria, Australia 2Maritime Division, Defence Science and Technology, Fishermans Bend, Victoria, Australia *Corresponding author: matt_watson@live.com.au ABSTRACT: Protozoa, a ubiquitous component of microbial biofilms, are able to rapidly colonise new substrata and reach high abundances, yet their potential to influence invertebrate settlement on these biofilms remains largely unknown. We conducted still-water, no-choice settlement assays to determine the individual effects of 4 different species of marine biofilm-dwelling ciliates on settlement of the polychaete worm Galeolaria caespitosa. The ciliates included vagile and planktonic species common to natural assemblages. Each ciliate species significantly inhibited the settlement of G. caespitosa, with the exception of Litonotus sp. The extent of inhibition differed significantly among ciliate species. Settlement was significantly reduced in the presence of Amphisiella sp. (37.5%), Euplotes minuta (43.7%) and Uronema marinum (39.6%) over 72 h compared to the control. Settlement rates in the presence of filtrate from ciliate cultures were at no point significantly different from a control, ruling out a dissolved chemical cue; settlement was only inhibited in the physical presence of ciliates. Video analysis showed that E. minuta elicits more erratic movement and substrate avoidance in surface exploration by G. caespitosa larvae. In addition, the distribution of bacteria in the ciliate treatments was significantly more clustered than in controls, indicating a potential indirect mechanism by which ciliates impacted larval settlement. This is the first report of a behavioural response of invertebrate larvae following direct contact with ciliates, which, together with possible indirect interactions involving bacteria, may constrain invertebrate recruitment in nature. KEY WORDS: Microbial biofilms · Ciliates · Microbial ecology · Marine invertebrates · Settlement · Galeolaria caespitosa Full text in pdf format PreviousNextCite this article as: Watson MG, Scardino AJ, Zalizniak L, Shimeta J (2016) Inhibition of invertebrate larval settlement by biofilm ciliates. Mar Ecol Prog Ser 557:77-90. https://doi.org/10.3354/meps11825 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 557. Online publication date: September 28, 2016 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2016 Inter-Research.