Continuous bubble streams for controlling marine biofouling on static artificial structures

Grant A Hopkins; Fletcher Gilbertson; Oli Floerl; Paula Casanovas; Matt Pine; Patrick Cahill

doi:10.7717/peerj.11323

Continuous bubble streams for controlling marine biofouling on static artificial structures

PeerJ. 2021 Apr 30:9:e11323. doi: 10.7717/peerj.11323. eCollection 2021.

Authors

Grant A Hopkins¹, Fletcher Gilbertson¹, Oli Floerl¹, Paula Casanovas¹, Matt Pine², Patrick Cahill¹

Affiliations

¹ Cawthron Institute, Nelson, New Zealand.
² Department of Biology, University of Victoria, B.C. Canada.

Abstract

Biofouling accumulation is not proactively managed on most marine static artificial structures (SAS) due to the lack of effective options presently available. We describe a series of laboratory and field trials that examine the efficacy of continuous bubble streams in maintaining SAS free of macroscopic biofouling and demonstrate that this treatment approach is effective on surface types commonly used in the marine environment. At least two mechanisms were shown to be at play: the disruption of settlement created by the bubble stream, and the scouring of recently settled larvae through shear stress. Field trials conducted over a one-year period identified fouling on diffusers as a major issue to long-term treatment applications. Field measurements suggest that noise associated with surface mounted air blowers and sub-surface diffusers will be highly localised and of low environmental risk. Future studies should aim to develop and test systems at an operational scale.

Keywords: Air bubbles; Marinas; Settlement; Static structures; Treatment.

Grants and funding

The publication of this work was supported by Cawthron’s Internal Investment Fund and New Zealand’s Ministry of Business, Innovation and Employment funding (CAWX1904—A toolbox to underpin and enable tomorrow’s marine biosecurity system). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.