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Seamounts are underwater mountains, often of volcanic origin, that rise above the surrounding seabed at least 100 m from the seabed but do not reach the surface. These underwater structures provide deep-sea hard substrate, allowing productive formation of deep-sea coral and sponge reef communities. Additionally, seamounts are considered highly productive, redirecting deep-sea currents rich in nutrients that attract a myriad of other marine organisms, such as fish and marine mammals.
Due to the volcanic history of the Galapagos Archipelago, hundreds of seamounts, ranging from > 3000 to 100 m in height, are known to be scattered on the seafloor in the reserve. Given that most seamounts lie outside the margins for safe SCUBA diving (< 40 m), and exploring deep-sea ecosystems is technologically and financially challenging, our understanding of seamounts and other deep-sea habitats remains very limited.
To close this critical knowledge gap CDF, in collaboration with the Galapagos National Park Directorate (GNPD), is leading a multi-institutional collaborative effort to characterize the biodiversity, ecology and physical environment of these mysterious deep-sea ecosystems.
Principal Investigator
Investigator
Project Assistant
This research project came together following three international oceanographic research cruises that took place between 2015-2016. In collaboration with CDF these expeditions, equipped with remotely operated vehicles (ROV) and manned submersibles, enabled the exploration of seamounts and lava flows at depths of 3200 to 100 meters.
Over 40 hours of video transects were recorded along seamount habitats and more than 300 biological samples of deep-sea organisms were collected. Additionally, the vessels carried out multiband bathymetry surveys over an area of 7065 km2 to support the development of high-resolution maps of the archipelago´s seafloor. Since 2016 our team has been analyzing this unique and valuable dataset, and working towards completing first large-scale characterization of the benthic habitats and biodiversity of these mysterious deep-sea spaces.
In 2018 we undertook a pilot study using small commercial ROVs to explore uncharted shallow seamounts, known to be key fishing sites, between depths of 200 to 30 m. A special characteristic of shallow seamounts is that they often reach the sunlight (euphotic) zone of the ocean, meaning that they potentially support a diverse range of marine habitats and mesophotic communities. After successfully video-surveying three shallow seamounts at different depth ranges, we will soon begin the analysis the videos to describe the habitats we found.
Our main goal is to complete the first comprehensive biophysical characterization of selected representative seamounts and other associated deep-sea ecosystems across the archipelago’s different bioregions.
With the help of expert taxonomist from all over the world so far we have identified more than 120 deep sea organism that were collected in the 2015-2016 expeditions. We have found that over half of these species are new records for the Galapagos and a few are potentially new species to science. Based on the analysis of video transects, we will be publishing the first inventories of deep-sea invertebrates for each phylum (e.g. Arthropoda, Mollusca, Cnidaria, etc.) on the online Ocean Biogeographic Information System (OBIS), accessible to the public. Additionally, we are currently analyzing the video transect data to produce the first description of the composition and distribution of deep-sea communities on seamounts in the Galapagos.
Although the in-depth analysis of the data set collected in the pilot study is about to start, preliminary results demonstrate the viability of surveying shallow seamounts with smaller and more affordable ROVs. What is more, we believe we have made an unexpected discovery: a kelp forest on the summit of one of the seamounts at a depth ~ 50 m. More results and details on this macroalgae habitat and other seamount ecosystems will be posted soon, so stay tuned for our next project blog posts.
Keywords: Seamounts, deep-sea, exploration, benthic invertebrates, new species
Galapagos National Park Directorate, Woods Hole Oceanographic Institution, Ocean Exploration Trust, National Geographic Pristine Seas, VideoRay, Southampton University, Smithsonian Institution, Louisiana State University, Boise State University, St Mary’s College, University of Victoria, Université Libre de Bruxelles, Universidad de los Andes, Smithsonian Natural Museum, Kumamoto University, University of Bristol, University of Hawaii, Texas A&M University, Universidad Nacional Autónoma de México.