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

AIMS AND SCOPE OF THE STUDY The expansion of human activities into deep sea areas is leading to an increase in the number of manmade structures on the seafloor below the shallowwater zone (<50 m depth; Jouffray et al., 2020). These structures provide a new type of habitat— hard substrate on or above the soft, sedimented bottom (e.g., Degraer et al., 2020). The development, composition, and abundance of biofouling organisms on these structures are much less studied than those in the shallow waters (Cowie, 2010). Only patchy observations exist on the temporal scale of the biofouling process on hard substrates below 50 m depth (e.g., Apolinario and Coutinho, 2009; Cowie, 2010; Bellou et al., 2012; Degraer et al., 2020). Thus, our understanding of biofouling temporal and spatial scales, and its variation with depth, is limited. One way to increase the amount of data available for addressing the development of fouling communities is collection of long-term observations using replicates of different duration (e.g., Hutchison et al., 2020). These timeand effortconsuming studies are usually based on specially designed installations mounted at different depths (e.g., Railkin, 2004). Here, we propose a simple approach for collecting biofouling observations along with primary hydrological and geophysical data. The small addition of test panels to standard oceanographic instrumentation can help to fill the gaps in our understanding of the development of biofouling communities in lesser-known areas. Here, we first present a literature review of the state of knowledge of marine biofouling to introduce the field’s terms, concepts, and knowledge gaps. We then present two case studies that support our proposed approach to collecting biofouling information, followed by identification of further steps, recommendations, and research opportunities that will improve our understanding of biofouling with increasing water depth in the ocean.