Publications

Climate-induced changes in environmental gradients can cause shifts in ranges of organisms and community composition, with concomitant effects on ecosystem functions. Throughout geological time, deeper depths have been highlighted as refugia for biodiversity and ecosystem functions under a warming climate. Although the deep ocean provides several important ecosystem services, contemporary research on climate effects at the community and ecosystem levels has been limited to the upper 200 m of the water column. As a result, our knowledge of climate-induced impacts on the functions of deep-sea ecosystems is scarce. In this study, we examined climate-induced changes in deep-sea communities at a climate-change hotspot, the Gulf of Maine and adjacent continental slope in the Northwest Atlantic. We focused on deep-water coral communities, which are among the most diverse in the deep sea. Using a joint species distribution model, we projected and examined community composition, taxonomic diversity, and trait diversity of deep-water coral communities under two climate scenarios for the end of the century (2100). We found extensive shifts of suitable habitat for several coral genera from 500–1000 to 1500–2000 m, mostly attributed to warming in the upper 1000 m. This led to substantial reduction (30%–60%) in the existing taxonomic and functional richness at the upper continental slope, alongside gains in richness (10%–15%) at the lower continental slope and bathyal zone. Our study is the first to report extensive shifts in biodiversity from mesopelagic to bathyal depths, which will inevitably cause redistribution of ecosystem functions and services. These results showcase that climate change impacts at the ecosystem level are not restricted to shallow depths and highlight that further knowledge of them is essential for efficient conservation, planning, and management.

The role of geological gross geomorphology (shape) as an abiotic control governing the abundance and diversity of deep-sea corals has not been previously considered, but has the potential to provide easily-accessible and transformative insight into deep water coral community dynamics. This study aims to investigate the influence of geological shape (e.g. atolls, islands, banks, guyots, conical, ridges) on deep-sea coral genera and habitats in the Pacific Ocean to determine whether feature shape is an important predictor of deep water biological communities. Multivariate analyses were used to test whether the gross geomorphology (shape) of islands and seamounts influences the abundance and diversity of deep water coral genera. Geological features across the entire Pacific basin were categorized using a standard classification scheme to determine their shape category. Across the 50 most abundant deep water coral genera in the data set, all 50 showed a statically significant preference for at least one geomorphology. Additionally, the abundance of the different feature shapes was not evenly distributed across the Pacific basin. Gross geomorphology influences the abundance and diversity of deep-sea corals across the central Pacific, which provides insight into deep water coral community structure and resulting conservation implications.

The growing threats to deep-sea ecosystems (e.g., offshore wind, seabed mining, aquaculture) have the potential to damage these understudied systems, and to impact the fisheries that they support. However, to date there has not been a uniform assessment identifying which commercially landed species are associated with the cold-water corals and other structure-forming invertebrates (SFI) found in the deep sea. We conducted a metanalysis to identify the species of fish and invertebrates landed by commercial fisheries in California, USA (2010–2024), and evaluate their potential associations with SFI. Captured species are assigned to Landing Categories, which range in specificity from individual species to broad taxonomic groups. We developed a referenced list of observations documenting associations, and used three metrics to identify which of the 313 Landing Categories are (or are not) associated with SFI: (1) Adjacent: species observed within one body length of SFI (target fish) or touching SFI (target invertebrates); (2) General proximity: species observed within the general area of SFI or based on modelling; (3) Habitat: species' depth ranges and habitat requirements suggest associations. Approximately 30% of Landing Categories were associated with cold-water SFI, but the specific percentage varied across metrics (Adjacent: 23%; General proximity: 27%; Habitat: 36%). Commercially targeted fish were more likely to be associated with SFI than invertebrates, but many invertebrates had undocumented life histories and/or non-specific Landing Categories. This study provides a step toward understanding the importance of SFI for commercial fisheries, and demonstrates the broad co-occurrence between commercially landed marine species and living deep-water habitats.

An investigation of Alaska’s extraordinarily rich sponge fauna was conducted utilizing samples retained as bycatch during National Marine Fisheries Service stock assessment bottom trawl surveys in the Gulf of Alaska and Aleutian Islands between 1997 and 2021. Subsequent analysis of the samples revealed four new species, which are representatives of four different orders of demosponges: Cladocroce cylindrica sp. nov., Julavis borealis sp. nov., Polycapus rubrum gen. nov. & sp. nov., and Stelletta plana sp. nov.. The new species are described and compared to congeners. Polycapus rubrum was assigned to the Hymedesmiidae but the combination of acanthoxeas and chelae does not occur in any other existing genus within the family which necessitates a new genus. These new collections further highlight the richness of the sponge fauna from the region.

This is a comprehen­sive, up-to-date guide, detailing 161 coral taxa identified from museum collections, primary literature, and video records. The guide provides informa­tion for targeting new collections and identifying areas of high abundance and indicator species of vulnerable marine ecosystems.

In Flower Garden Banks National Marine Sanctuary region within the northwestern Gulf of Mexico, sponges thrive among diverse biological and geological habitats between 16–200+ m deep (i.e., coral reefs and communities, algal nodules, and coralline algae reefs, mesophotic reefs, patch reefs, scarps, ridges, soft substrate, and rocky outcrops). A synoptic guide is presented, developed by studying common sponge species in the region, through direct sampling and in-situ photographic records. This work improves our knowledge of Gulf of Mexico sponge biodiversity and highlights the importance of the region for scientists and resource managers.

Shore-based submersible operations, from 2006 to 2020, have allowed us to examine megabenthic assemblages along the island margin of Isla de Roatán from depths of about 150 to 750 m, including repeated observations of the same organisms. These dives were used to photo-document a diverse benthic assemblage and observe the health and condition of the sessile fauna in a well-explored but relatively undocumented area of the Mesoamerican Reef.

This study analyzed alpha and beta diversity of mesophotic coral forests on fourteen topographic banks in the northwestern Gulf of Mexico. The objective of the study was to examine differences in structure and community in relation to lease stipulations established by the Bureau of Ocean and Energy Management.

The Pourtalès Terrace is an exposed hard-bottom platform located south of the Florida Keys in 200–450 m depth with a diverse deep-sea coral ecosystem dominated by stylasterid hydrocorals, octocorals, and sponges that supports recreational and commercial fisheries. Here we report analyses of historic Terrace physiographic and geologic data with more recent high-resolution bathymetric and benthic data to statistically derive a benthic community characterization across the Terrace.

We provide the first consideration of larval connectivity among deep-sea sponge populations along the southeastern coast of North America, illustrate the influence of the Gulf Stream on dispersal, and complement published distribution models by evaluating colonization potential.