Managing Biofouling on Submerged Static Artificial Structures in the Marine Environment – Assessment of Current and Emerging Approaches

Grant Hopkins,Patrick Cahill,Oliver Floerl,Donald Morrisey,Ian Davidson,Eugene Georgiades

doi:10.3389/fmars.2021.759194

Abstract

The number, extent, diversity, and global reach of submerged static artificial structures (SSAS) in the marine environment is increasing. These structures are prone to the accumulation of biofouling that can result in unwanted impacts, both immediate and long-term. Therefore, management of biofouling on SSAS has a range of potential benefits that can improve structure functions, cost-efficiency, sustainability, productivity, and biosecurity. This review and synthesis collates the range of methods and tools that exist or are emerging for managing SSAS biofouling for a variety of sectors, highlighting key criteria and knowledge gaps that affect development, and uptake to improve operational and environmental outcomes. The most common methods to manage biofouling on SSAS are mechanical and are applied reactively to manage biofouling assemblages after they have developed to substantial levels. Effective application of reactive methods is logistically challenging, occurs after impacts have accumulated, can pose health and safety risks, and is costly at large scales. Emerging technologies aim to shift this paradigm to a more proactive and preventive management approach, but uncertainty remains regarding their long-term efficacy, feasibility, and environmental effects at operational scales. Key priorities to promote more widespread biofouling management of SSAS include rigorous and transparent independent testing of emerging treatment systems, with more holistic cost-benefit analyses where efficacy is demonstrated.

Highlights

A burgeoning human population is dramatically increasing the number, extent, diversity, and reach of submerged static artificial structures (SSAS) in the marine environment (Firth et al, 2016; Todd et al, 2019; Floerl et al, in press)
High-pressure washing and mechanical methods failed the Biosecurity and Collateral Effects criteria due to risks associated with the potential release of viable propagules, organic material, or chemical contaminants during treatment
For the energy and ports and marina industries, the Feasibility criterion was the biggest implementation hurdle, as many of the present-day tools would be cost-prohibitive or impractical to apply at scale or to SSAS types associated with these industries

Summary

Introduction

A burgeoning human population is dramatically increasing the number, extent, diversity, and reach of submerged static artificial structures (SSAS) in the marine environment (Firth et al, 2016; Todd et al, 2019; Floerl et al, in press). Over the last century, floating pontoons, industrial water-use structures (e.g., power plants), oil and gas rigs, desalination plants, marine-farming installations, wave buoys, turbines, and other renewable-energy infrastructure have added to increasing amounts of traditional structures (Bugnot et al, 2020; Floerl et al, in press) All of these structures are subject to constant colonization pressure by microorganisms, macroalgae, and invertebrates – commonly. In nuclear power plants, biofouling has caused significant pressure drops in cooling water systems that impose serious production penalties and can instigate safety concerns (Neitzel et al, 1984, Satpathy, 1999) All of these direct outcomes necessitate heightened engineering considerations prior to installation to cope with loss of hydrodynamic performance, weight loading scenarios, and impaired functioning that requires increased initial investment, operating, and maintenance costs (Jenner et al, 1998; Polman et al, 2013)

Results

Discussion

Conclusion