Table 1 A non-exhaustive list of key sessile (micro)organism groups in marine biofouling communities.

Biofilms^5,6

Archaea

Bacteria

Fungi

Microalgae (mainly diatoms)

Protists

The marine biofilm acts as the foundation on which the subsequent biofouling community is built. The biofilm provides an adhering layer for micro- and macro-fouling organisms alike and has been observed to be critical in the attachment and growth of a variety of sessile marine species.

Biocalcifying microorganisms^55,56,93,94

Bacterial groups such as Cyanobacteria, sulfate-reducing bacteria, denitrifying bacteria and ureolytic bacteria.

Calcareous diatoms

The metabolic processes of these microorganisms can induce precipitation of calcium carbonate in their immediate surrounding leading to scaling and associated issues with hard fouling.

Morphogenesis agents^22,23,25

Marine invertebrates (Notable bacteria include Pseudoalteromonas luteoviolacea, Cellulophaga lytica, Bacillus aquimaris and Staphylococcus warneri)

Algae (Roseovarius sp. MS2 and Maribacter sp.

MS6 for the green algae genus Ulva; co-culture containing several Proteobacteria candidates for brown algae Ectocarpus sp.)

Several bacterial species have been observed to be critical for the morphogenesis of marine invertebrate larvae and algal spores into their sessile forms, promoting the propagation of many macro-fouling organisms.

Biofilm-based viruses³⁴

Double stranded DNA viruses (Notable examples from Class Caudoviricetes and Class Maveriviricetes)

Biofilm-based viruses have been observed to integrate into bacterial genomes, appearing to provide functional genes for adhesins and polysaccharide metabolism. This integration can potentially increase the biofilm formation capabilities of the host bacteria.

Macro-fouling organisms^{9,95,96,97,98,99}

Bivalve molluscs (Phylum Mollusca, Class Bivalvia)

Barnacles (Phylum Arthropoda, Class Thecostraca)

Bryozoans (Phylum Bryozoa)

Calcaerous tubeworms (Phylum Annelida, Class Polychaeta)

Hard corals (Phylum Cnidaria, Class

Anthozoa, Order Scleractinia)

Soft corals (Phylum Cnidaria, Class

Anthozoa, Order Alcyonacea)

Hydroids (Phylum Cnidaria, Class Hydrozoa)

Sea Anemones (Phylum Cnidaria, Class

Anthozoa, Order Actiniaria)

Ascidians, tunicates and seq squirts (Phylum Chordata, Class Ascidiacea)

Marine sponges (Phylum Porifera)

Green algae (Division Chlorophyta)

Brown algae and kelp (Phylum Gyrista, Class Phaeophyceae)

Red algae (Division Rhodophyta)

Uncontrolled growth can lead to increased weight and rugosity of affected structures, compromising structural integrity and efficient operation of traveling vessels.

Coverage of vital structural component such as sensors, connectors and moving parts can inhibit the operation of maritime machinery.

Increased operational costs due to additional cleaning requirements, as well as increased fuel costs due to drag on maritime vessels.