Leila Hamdan, University of Southern Mississippi
Microorganisms are essential to the function, habitability, and biodiversity of all seafloor ecosystems. Due to their small size, they lie invisible in plain sight. Yet they are abundant and present in all habitats on Earth. The seafloor is rich with natural habitats and built structures, including shipwrecks. These provide physical habitats for life in the sea. They also support the global biodiversity of the ocean. Marine sediments are among the most diverse ecosystems on the planet, with up to 10,000x times more microorganisms than ocean waters. However, the seafloor remains a frontier for discovery of habitats and their associated microbes.
Built environments are human-made features and structures. There are numerous examples of these in the ocean, including oil and gas infrastructure and shipwrecks. These environments may be as significant to biodiversity as natural structures and are thus deserving of scientific attention.
The collective microorganisms, their genetic elements and their interaction with the surrounding environment at a certain place is known as a microbiome. Once a microbiome is established on a built structure, larger organisms, including corals, crabs, fish and bivalves are drawn to these places, giving rise to artificial reefs.
Fig. 1. Sediment coring around shipwreck site #15711 during the Microbial Stowaways expedition, supported by NOAA Ocean Exploration in July 2019. Image courtesy of Microbial Stowaways. Download largest version (jpg, 2.0 MB).
Our work through this and other NOAA supported studies are helping us recognize built features as habitats that support biodiversity and biogeography (distribution across space and time) of seafloor microbes.
Fig. 2. A crab stops by to inspect coring operations around shipwreck site #15470 in the northern Gulf of Mexico. Image captured by Remotely Operated Vehicle Odysseus, courtesy of Microbial Stowaways. Download image (jpg, 118 KB).
The Gulf of Mexico has more than 2,000 known historic shipwrecks. It is likely that these shipwrecks shape the environment in ways never before understood. We hypothesize shipwrecks increase the local microbial biodiversity of surrounding sediments and support the transport and evolution of microbes between them. Since historic shipwrecks are somewhat isolated from another, each shipwreck could be considered an island .
Our goal is to discover how shipwrecks shape life in the ocean on local, regional and global scales. For this study, we will investigate if microbiome diversity is impacted by the presence of the shipwreck Norlindo on the seabed. This work will connect with recent discoveries centered on other historic shipwrecks in the Gulf of Mexico. The microbiology study of Norlindo, will aid work to devise tools to use microorganisms to point the way to new shipwrecks on the seabed.
Published August 16, 2021
