At the Interface of Marine Disciplines: Use of Autonomous Seafloor Equipment for Studies of Biofouling Below the Shallow-Water Zone

Biofouling of artificial substrates is a well-known phenomenon that can negatively impact offshore industry operations as well as data collection in the ocean. Fouling communities worldwide have mostly been studied within the top 50 m of the ocean surface, while biofouling below this depth remains largely underreported. Existing methods used to study biofouling are labor intensive and expensive when applied to the deep sea. Here, we propose a simple and cost-effective modification of traditional methods for studying biofouling by mounting test plates on autonomous seafloor equipment and preserving them in ethanol upon retrieval for transport to the laboratory. This method can greatly advance our understanding of biofouling processes in the deeper ocean, including fouling community biodiversity, recruitment, and seasonality. We present two case studies from the Laptev Sea and the Sea of Okhotsk in support of this method. In the first study, we looked at fouling communities on the surfaces of ocean-bottom seismometers deployed for one year in the 36–350 m depth range. In the second study, we tested metal and plexiglass (poly(methyl methacrylate) plates mounted on autonomous bottom stations and found evidence of both micro- and macrofouling after three months of deployment. Our results demonstrate that various autonomous seafloor equipment can be used as supporting platforms for biofouling studies.

A small collection of Endeis juveniles (Arthropoda: Pycnogonida: Endeidae) sorted from the fouling organisms on the R/V Dayangyihao

Endeis straughani Clark, 1970 was originally described from Queensland, Australia. Its range was extended to Ghana, West Africa when E. picta Bamber, 1979 was synonymised with E. straughani by Staples (1982). The current paper extends this range further, to include Port Louis, Mauritius. Five immature individuals gathered amongst hydroids during the 5th leg of the DY125-34 expedition were tentatively identified as E. straughani juveniles. Since these were collected from the fouling community on the ship’s hull, they probably originated in Port Louis (Mauritius) when the ship was docked there.

Taxonomic structure of the coastal fouling community formed by the Black Sea mussel Mytilus galloprovincialis

Peculiarities of the taxonomic structure of the coastal fouling community formed by the bivalve mollusk Mytilus galloprovincialis Lamarck, 1819 on the underwater surface of solid substrates located in the Odessa Bay of the Black Sea have been revealed. The qualitative composition, degree of occurrence, size characteristics and features of quantitative development of invertebrates of this community were determined. As part of the fouling community, 65 species of invertebrates belonging to 61 genera, 47 families, 22 orders, 10 classes and 6 types were identified. It was found that among the large taxa of the community Cnidaria, Annelida, Bryozoa, Arthropoda, Mollusca, Chordata, the most numerous species was the Arthropod type. Annelida and Mollusca accounted for one-fifth and one-fourth of all species. The other three types of invertebrates were represented by one or two species. A characteristic feature of the taxonomic structure of the community was that in most cases, each identified genus was represented by only one species, which in specific conditions was the most environmentally plastic representative of it. It is shown that the species structure of the fouling community was characterized by evident dominance of its edificator M. galloprovincialis. The maximum abundance of this species in the community was 11960 sp.·m-2, and biomass – 10328,6 g·m-2. In addition, 12 other invertebrates with 100 % occurrence were key-species of the community. These species, together with those with occurrence of more than 75 %, belonged to the characteristic species of the community. A total of 22 such species were identified. Among other invertebrates, 5 species (P = 50–75 %) were permanent, 8 species (P = 25–50 %) were rare, and 30 species (P <25 %) were random. The most of the organisms in the coastal fouling community of the Odessa Bay are eurybiont species was established. The presence in the fouling community invasive species of bivalve mollusks Arcuatula senhousia (Benson, 1842), which is systematically very close to the Black Sea mussel Mytilus galloprovincialis, was revealed. Due to its opportunistic properties, this mollusk poses a certain threat to the existence of settlements of aboriginal species of bivalve mollusks. The coastal fouling community formed by the Black Sea mussel has a certain degree of stability, as the same species of invertebrates remain characteristic of its taxonomic structure for 40 years.