Geology topics

Amanda Demopoulos

Publications and source records attributed to Amanda Demopoulos.

At least 19 recordsLinked to original sources

USGS2025

Spawning and larval development of the mesophotic octocoral Swiftia exserta in aquaria

The 2010 Deepwater Horizon oil spill injured mesophotic and deep-sea environments over a vast area. In order to restore mesophotic and deep-sea coral species impacted by the spill, information on fundamental ecosystem processes such as reproduction is needed. During expeditions in 2021 and 2022, fragments of the mesophotic octocoral Swiftia exserta were collected from the northern Gulf of Mexico and transported to aquaria at federal facilities in South Carolina, Florida, and Texas. In fall of 2021 and 2022, several of these fragments spawned in captivity, providing an opportunity to learn about their reproduction and inform future restoration activities. Broadcast spawning occurred on 19 and 20 October, 2021, and on 20 days from 29 September to 7 November, 2022. These spawning events permitted detailed observations of spawning behavior and timing, and yielded over 2,400 oocytes. Individual spawns were preceded by a distinctive “spawning posture” in the polyps, lasting between five minutes and two hours, and may have been cued by light. Swiftia exserta larvae settled and developed at comparable rates to other broadcast spawning octocorals, becoming swimming planulae by three days post spawn (dps) and starting to settle by 14 dps. These observations represent the first such records for S. exserta and, more broadly, for any mesophotic coral in the Gulf of Mexico, providing important insights for the restoration of these species. This investigation lays the foundation for future work to explore the influences of seasonal environmental variables, such as light and temperature, on spawning and reproductive seasonality in this species.

Marine Biology↗

USGS2024

Benthic community metrics track hydrologically stressed mangrove systems

Mangrove restoration efforts have increased in order to help combat their decline globally. While restoration efforts often focus on planting seedlings, underlying chronic issues, including disrupted hydrological regimes, can hinder restoration success. While improving hydrology may be more cost-effective and have higher success rates than planting seedlings alone, hydrological restoration success in this form is poorly understood. Restoration assessments can employ a functional equivalency approach, comparing restoration areas over time with natural, reference forests in order to quantify the relative effectiveness of different restoration approaches. Here, we employ the use of baseline community ecology metrics along with stable isotopes to track changes in the community and trophic structure and enable time estimates for establishing mangrove functional equivalency. We examined a mangrove system impacted by road construction and recently targeted for hydrological restoration within the Rookery Bay National Estuarine Research Reserve, Florida, USA. Samples were collected along a gradient of degradation, from a heavily degraded zone, with mostly dead trees, to a transition zone, with a high number of saplings, to a full canopy zone, with mature trees, and into a reference zone with dense, mature mangrove trees. The transition, full canopy, and reference zones were dominated by annelids, gastropods, isopods, and fiddler crabs. Diversity was lower in the dead zone; these taxa were enriched in 13 C relative to those found in all the other zones, indicating a shift in the dominant carbon source from mangrove detritus (reference zone) to algae (dead zone). Community-wide isotope niche metrics also distinguished zones, likely reflecting dominant primary food resources (baseline organic matter) present. Our results suggest that stable isotope niche metrics provide a useful tool for tracking mangrove degradation gradients. These baseline data provide critical information on the ecosystem functioning in mangrove habitats following hydrological restoration.

Florida↗

USGS2024

Consumer isoscapes reveal heterogeneous food webs in deep-sea submarine canyons and adjacent slopes

The deep sea is the largest biome on earth, but one of the least studied despite its critical role in global carbon cycling and climate buffering. Deep-sea organisms largely rely on particulate organic matter from the surface ocean for energy – these organisms in turn play critical roles in energy transport, transformation, storage, and sequestration of carbon. Within the deep sea, submarine canyons are amongst the most complex and dynamic environments in our oceans, where varied morphology, powerful currents, and variable nutrient conditions influence the distribution of species and transport of organic material throughout the water column and the seafloor. Significant habitat heterogeneity provides ideal substrates for cold-water corals, making submarine canyons of interest to conservation and management. However, how these and other topographic features in the deep ocean influence energy flow and trophic pathways is poorly known. Thus, submarine canyons serve as model systems to track variability in organic material flux and consequential utilization and assimilation by the benthos. In this study, we used an extensive stable isotope dataset to examine food-web structure in Baltimore and Norfolk submarine canyons and compared them to their adjacent slopes located along the U.S. Atlantic margin. Linear models were used to construct geospatially-explicit consumer isoscapes that predicted variation in carbon and nitrogen isotopes across the canyon-slope seascape, providing a predictive map from which to test hypotheses on the distribution and flow of energy resources, relevant to understanding whole community function. Communities were composed of isotopically diverse feeding groups with photosynthetically-derived organic carbon providing the basal food resource. Canyon communities were distinct from the slope, with canyon consumers significantly 13 C-depleted, indicating a greater supply and/or utilization of fresh organic matter compared to the slope. Isoscapes for benthic and suspension feeders were distinct, possibly due to the consumption of different quality organic matter sources (fresh = suspension feeders, old = benthic feeders), each with distinct isotope composition. To our knowledge, our modeled isoscapes represent the first spatially extensive isotopic maps of deep-sea consumers, providing insights into regional-scale variation in stable carbon and nitrogen isotopes for different consumer groups. They provide a baseline for tracking climate-change induced fluctuations in the quality and availability of surface primary production and the consequential impact to benthic communities, which play critical roles in carbon cycling in our world’s oceans.

Progress in Oceanography↗

USGS2024

The National Ocean Biodiversity Strategy

President Biden has been clear that the ocean is central to life on Earth. As he has proclaimed, “the ocean powers millions of jobs; feeds and sustains us; and is a rejuvenating source of inspiration, exploration, and recreation.” The Biden-Harris Administration has worked hard to fulfill the President’s goal to protect and conserve at least 30% of U.S. waters by 2030. The ocean faces increased threats from warming, overfishing, increased acidity, and loss of biodiversity. It is now more important than ever to sustain the many benefits that the ocean, coasts, and Great Lakes provide, including food, a favorable climate, recreation, physical and mental health, and for many, a sense of cultural identity. Ocean life represents an irreplaceable heritage, the foundation of a habitable planet, and a vast trove of resources. Keeping our ocean healthy requires reliable information on the changing status of these living organisms, the drivers of biodiversity change, and options for effectively addressing those drivers. Over 2 million species are estimated to live in the ocean, yet only about 240,000 species have been described by scientists. Most of the ocean’s benefits result from those diverse species interacting with one another and the environment they create. To protect and conserve the ocean, we as a nation need to make better use of existing knowledge and prioritize acquiring new biodiversity knowledge to enable better policy and management decisions. The ability to monitor ocean species and habitats has expanded dramatically over the past decade, with innovations in technology, genomics, taxonomy, big data management and sharing, artificial intelligence, and machine learning. Yet large fractions of the U.S. ocean remain almost unknown. The National Ocean Biodiversity Strategy (strategy) reflects the urgent need to leverage these advances. The goals of this strategy must be guided by the nation’s diverse voices and ways of knowing, in order to maximize effective and equitable stewardship of the ocean’s diverse life and its benefits to people. The strategy is intended as a guiding document for government to advance three overarching goals: ● Goal 1: Drive delivery of ocean biodiversity knowledge at the national scale. Objectives include developing an Implementation Plan for achieving the strategy’s three goals; establishing a coordination mechanism to manage the implementation; and documenting gaps in biodiversity knowledge and the benefits of ocean biodiversity to people and economies. ● Goal 2: Strengthen tools and institutions to deliver ocean biodiversity knowledge. Objectives include establishing a robust information pipeline to support indicators and dynamic maps of ocean biodiversity, from the coasts to the deep sea. This pipeline should include expanded observing systems and comprehensive data management; science and technology solutions to accelerate the availability of biodiversity information; and plans to leverage previous investments to rebuild and expand the nation’s human capital and infrastructure to sustain foundational taxonomy and biodiversity science. ● Goal 3: Protect, conserve, restore, and sustainably use ocean biodiversity. Objectives include expanding the collection, delivery, and use of biodiversity knowledge to inform actions that advance ocean protection, conservation, restoration, and sustainable development. Government should lead in establishing and incentivizing diverse partnerships across scales and sectors to implement those actions and should educate and involve the public to discover and value the nation’s diverse ocean life. Achieving these goals will require commitments across society: new federal and private investments, coordination across sectors to address climate and equity challenges, and engagement of Indigenous Knowledge holders and frontline communities as full partners throughout planning and implementation. The Subcommittee on Ocean Science and Technology (SOST) IWG-Biodiversity will begin developing an Implementation Plan to describe and direct specific actions to implement the strategy. Successful implementation of the strategy will harmonize and expand collection and delivery of timely knowledge on ocean life to all of society. The strategy will also enable evidence-based management and protection of the ocean. Advancing the strategy will build human and institutional capital and partnerships that support both existing mandates and new needs to rebuild and sustain biodiversity, achieve healthy ocean ecosystems, and manage living resources. Implementing the strategy will deliver knowledge for monitoring, modeling, forecasting, and assessments that support food security, public health, and cultural values, and that more effectively protect, conserve, and restore nature.

Report↗

USGS2023

Expanding our view of the cold-water coral niche and accounting of the ecosystem services of the reef habitat

Coral reefs are iconic ecosystems that support diverse, productive communities in both shallow and deep waters. However, our incomplete knowledge of cold-water coral (CWC) niche space limits our understanding of their distribution and precludes a complete accounting of the ecosystem services they provide. Here, we present the results of recent surveys of the CWC mound province on the Blake Plateau off the U.S. east coast, an area of intense human activity including fisheries and naval operations, and potentially energy and mineral extraction. At one site, CWC mounds are arranged in lines that total over 150 km in length, making this one of the largest reef complexes discovered in the deep ocean. This site experiences rapid and extreme shifts in temperature between 4.3 and 10.7 °C, and currents approaching 1 m s −1 . Carbon is transported to depth by mesopelagic micronekton and nutrient cycling on the reef results in some of the highest nitrate concentrations recorded in the region. Predictive models reveal expanded areas of highly suitable habitat that currently remain unexplored. Multidisciplinary exploration of this new site has expanded understanding of the cold-water coral niche, improved our accounting of the ecosystem services of the reef habitat, and emphasizes the importance of properly managing these systems.

Scientific Reports↗

USGS2023

One byte at a time: Gathering best practices, guidelines, and resources for data standards to support ocean exploration and characterization

Initiated through Presidential direction and now codified, the National Ocean Mapping, Exploration, and Characterization (NOMEC) Council comprises leaders from U.S. federal agencies with a shared goal of mapping all waters of the United States and exploring and characterizing priority areas. The NOMEC Council’s two Interagency Working Groups, Ocean and Coastal Mapping (IWG-OCM) and Ocean Exploration and Characterization (IWG-OEC), both achieved major milestones recently with the 2023 release of the Draft Standard Ocean Mapping Protocols (SOMP) and the 2022 publication of the National Priorities for Ocean Exploration and Characterization. Building on this groundwork, the IWG-OEC is now looking to define and share best practices, guidelines, and resources for ocean exploration and characterization with the long-term goal of increasing community wide standardization to help achieve consistent common practices. First, the IWG-OEC plans to compile federal agency resources and share them in a newly developed online resource repository. The next phase is for the IWG-OEC to create opportunities for non-federal sectors to provide input on developing and populating this repository with additional content (existing standards and protocols, best practice and guidelines documents, etc.). After experts representing multiple sectors are identified, a series of results-oriented workshops are planned to provide input on all aspects of the data, products, and services from exploration and characterization. Finally, the IWG-OEC plans to widely share the online repository of best practices and standard operating procedures. A systematic, transparent, and collaborative process to share standards and protocols can help to enhance the interoperability of data and inform new lines of inquiry, discovery, research, and innovation.

Frontiers in Marine Science↗

USGS2023

Comprehensive inventory of habitat assessment and evaluation datasets to support Deepwater Horizon mesophotic and deep benthic communities

This report is part of the NOAA Mesophotic and Deep Benthic Communities (MDBC) Series of publications that share the results of work conducted by the Deepwater Horizon MDBC restoration projects. The 2010 Deepwater Horizon oil spill was an unprecedented event. Approximately 3.2 million barrels of oil were released into the deep ocean over nearly three months. The plume of oil moved throughout the water column, formed surface slicks that cumulatively covered an area the size of Virginia, and washed oil onto at least 1,300 miles of shoreline habitats. More than 770 square miles (2,000 square kilometers) of deep benthic habitat surrounding the Deepwater Horizon wellhead and 4-square miles of the Pinnacles mesophotic reef complex, located at the edge of the continental shelf, were injured by the oil spill. Under the Oil Pollution Act, state and federal natural resource trustees conducted a Natural Resource Damage Assessment (NRDA). The Trustees assessed damages, quantifying the unprecedented injuries to natural resources and lost services. They also developed a programmatic restoration plan to restore injured resources and compensate the public for lost services. In April 2016, a settlement was finalized that included up to $8.8 billion in funding for the Deepwater Horizon Trustees to restore the natural resource injuries caused by the oil spill as described in their programmatic restoration plan, Final Programmatic Damage Assessment and Restoration Plan and Final Programmatic Environmental Impact Statement. The Deepwater Horizon Open Ocean Trustee Implementation Group is responsible for restoring natural resources and their services within the Open Ocean Restoration Area that were injured by the oil spill. The Open Ocean Trustees include NOAA, Department of the Interior, U.S. Environmental Protection Agency, and U.S. Department of Agriculture. In 2019, the Open Ocean Trustee Implementation Group committed more than $126 million to implement four restoration projects to address the injury to MDBC. The MDBC projects are: mapping, Ground-truthing, and Predictive Habitat Modeling; Habitat Assessment and Evaluation; Coral Propagation Technique Development; and Active Management and Protection. NOAA and the Department of the Interior are implementing the projects, in cooperation with a range of partners, over eight years. Together, the projects take a phased approach to meet the challenges involved in restoring deep-sea habitats. Challenges to restoration include a limited scientific understanding of these communities, limited experience with restoration at the depths at which these communities occur, and remote locations that limit accessibility. More information about Deepwater Horizon restoration and the MDBC restoration projects is available at: www.gulfspillrestoration.noaa.gov.

Gulf of Mexico↗

USGS2023

Cruise Report for NOAA Ship Nancy Foster Cruise NF-22-06

Between 9 August and 1 September, 2022, the Mesophotic and Deep Benthic (MDBC) Habitat Assessment and Evaluation (HAE) and Mapping, Ground-truthing, and Predictive Habitat Modeling (MGM) projects implemented remotely operated vehicle (ROV) dives, multibeam surveys, and conductivity, temperature, depth (CTD) operations at deep-sea sites in the northern Gulf of Mexico. The primary sites selected are a region of known deep-sea coral habitats, including Deepwater Horizon (DWH) injured and reference sites at depths of 1,100–2,000 m. The cruise includes objectives from MGM and HAE projects. Habitat characterization and analysis of biological samples collected with ROV Odysseus maintain long-term data flows and fill critical data gaps on the biology and ecology at impacted and reference sites, assess potential ongoing impacts from threats, refine predictive habitat models, help target locations for direct restoration and protection, and determine a baseline for health and condition. Multibeam echosounder data can help document the broadscale abundance and distribution of MDBC, characterize benthic habitats, and provide information that can help guide future ROV surveys.

DWH MDBC Cruise Report↗

USGS2022

Workshops report for mesophotic and deep benthic community fish, mobile invertebrates, sessile invertebrates and infauna

Two workshops with subject matter experts in the appropriate fields, were held in November and December 2021 to elicit guidance and feedback from the broader mesophotic and deep benthic scientific community. These workshops focused on best practices/approaches and identifying data gaps relative to habitat assessment and evaluation goals of the Mesophotic and Deep Benthic Community (MDBC) restoration portfolio. The first workshop was a combined effort of the Habitat Assessment and Evaluation (HAE) Project Team and the Deepwater Horizon (DWH) Program. Industrial Economics, Inc. (IEc) provided extensive workshop planning, organizing, execution, and facilitation support during all stages of the workshop. Based on a questionnaire sent to scientists in August, 2021, the workshop focused on fish and mobile invertebrate habitat associations, abundance trends, community metrics, and food web functionality. Topical presentations and discussions focused not only on demersal fish and mobile invertebrates that are directly associated with mesophotic and deep benthic habitats, but also considered water column species and communities that benefit from these habitats more broadly. The second workshop, intended to complement the first workshop, focused on identifying best practices and critical information gaps for key community metrics, larval dispersal modeling, connectivity, effects and variability of environmental parameters, and recovery trajectories of corals, infauna, and other sessile invertebrates. Through literature review, internal HAE scientists considered these topics to be critical for restoration success. Products from the literature review included topical summaries (see Appendix B) that summarized the current state-of-the-science and provided the framework for the workshop. Information generated from the workshops will assist the MDBC HAE Project, and more broadly the DWH Program, identify data gaps and develop a suite of best practices for restoration activities.

DWH MDBC Summary Report↗

USGS2022

A characterization of the deep-sea coral and sponge community along the California, Oregon, and Washington coasts using a remotely operated vehicle on the EXPRESS 2019 expedition

NOAA’s Deep-Sea Coral Research Technology Program (DSCRTP) began a 4-year funding initiative for the U.S. West Coast in 2018. The goals of the West Coast Deep-Sea Coral Initiative were to: 1) gather baseline information on DSCS in areas subject to fishing regulation changes prior to the implementation of Amendment 28; 2) improve our understanding of known DSCS bycatch “hot spots”; and 3) explore and assess DSCS resources within NOAA National Marine Sanctuaries with emphasis on areas of sanctuary resource protection and management concerns. Following the 2018 research expedition supported by NOAA Ship Bell M. Shimada (Laidig et al., 2021), a second research cruise was planned for 2019 to further survey seafloor communities in priority areas off the West Coast from Washington to California. The 2019 expedition spanned 35 days (4 Oct – 7 Nov) and was conducted from the NOAA Ship Reuben Lasker (hereafter referred to as “the ship”), beginning and ending in San Diego, CA. Surveys were conducted in deeper areas (generally 500-1200 m) in 2019 than in 2018 (limited to <650 m). These two expeditions provide data on seafloor communities and DSCS assemblages over a broad range of depths 50-1200 m.

California, Oregon, Washington↗

USGS2021

Potential for carbon and nitrogen sequestration by restoring tidal connectivity and enhancing soil surface elevations in denuded and degraded south Florida mangrove ecosystems

Mangroves are tidally dependent wetlands that are influenced often by alterations in hydrology associated with coastal developments that impact their distribution, health, and function. Alteration in frequency, depth, duration, and seasonality of tidal inundation can lead to changes in forest condition, although these stress-adapted ecosystems may persist for many years before succumbing to mortality. However, arresting this decline through hydrological restoration can significantly improve ecosystem condition and the provision of ecosystem services. Much of the mangrove resource on Marco Island, Florida, USA, is unhealthy if not already dead or dying due to soil structural shifts, permanent flooding, and peat compression resulting from road construction, tidal restriction, and delays in restoration actions. In order to determine the impact of restricted hydrology on these mangrove forests, we examined soil surface elevation change and soil carbon (C) and nitrogen (N) content along a degradation gradient and within a small-scale, community-driven restoration area. Using a space-for-time substitution approach, we found that the restoration of regular tidal inundation to Marco Island mangroves has the potential to increase C sequestration in surface soils alone from 0 to 360 g C/m 2 /yr (3.60 Mg C/ha/yr) and increase N sequestration from 0 to 24 g N/m2/yr (0.24 Mg N/ha/yr). Additional sequestration benefits would be realized with aboveground forest recovery. Successful mangrove restoration trials and small community-based projects such as those on Marco Island could serve as a model for larger efforts and empower stakeholders and policy makers to restore other wetlands and better manage coastal carbon.

Florida↗

USGS2021

New geochemical tools for investigating resource and energy functions at deep-sea cold seeps using amino-acid δ15N in chemosymbiotic mussels (Bathymodiolus childressi)

In order to reconstruct the ecosystem structure of chemosynthetic environments in the fossil record, geochemical proxies must be developed. Here, we present a suite of novel compound-specific isotope parameters for tracing chemosynthetic production with a focus on understanding nitrogen dynamics in deep-sea cold seep environments. We examined the chemosymbiotic bivalve Bathymodiolus childressi from three geographically distinct seep sites on the NE Atlantic Margin and compared isotope data to non-chemosynthetic littoral mussels to test whether water depth, seep activity, and/or mussel bed size are linked to differences in chemosynthetic production. The bulk isotope analysis of carbon (δ 13 C) and nitrogen (δ 15 N), and δ 15 N values of individual amino acids (δ 15 N AA ) in both gill and muscle tissues, as well as δ 15 N AA- derived parameters including trophic level (TL), baseline δ 15 N value (δ 15 N Phe ), and a microbial resynthesis index (Σ V ), were used to investigate specific geochemical signatures of chemosynthesis. Our results show that δ 15 N AA values provide a number of new proxies for relative reliance on chemosynthesis, including TL, ∑V, and both δ 15 N values and molar percentages (Gly/Glu mol% index) of specific AA. Together, these parameters suggested that relative chemoautotrophy is linked to both degree of venting from seeps and mussel bed size. Finally, we tested a Bayesian mixing model using diagnostic AA δ 15 N values, showing that percent contribution of chemoautotrophic versus heterotrophic production to seep mussel nutrition can be directly estimated from δ 15 N AA values. Our results demonstrate that δ 15 N AA analysis can provide a new set of geochemical tools to better understand mixotrophic ecosystem function and energetics, and suggest extension to the study of ancient chemosynthetic environments in the fossil record.

Geobiology↗

USGS2021

The role of habitat heterogeneity and canyon processes in structuring sediment macrofaunal communities associated with hard substrate habitats in Norfolk Canyon, USA

Topographic and hydrodynamic complexity in submarine canyons promotes steep gradients in food availability and geophysical parameters which affect ecological assemblages and beta diversity. While habitat heterogeneity in submarine canyons is known to support diverse and abundant megafaunal communities, due to difficulty in sampling little is known about infaunal communities adjacent to hard substrate habitats, their contribution to canyon assemblages, and overall deep-sea diversity. Sediments were collected in three distinct habitat types: within Norfolk Canyon (western Atlantic) adjacent to hard substrate habitats including canyon walls and large boulders, along the main axis of the canyon, and on the adjacent continental slope to quantify macrofaunal (>300 μm) density, diversity and community composition, and sediment geochemical parameters including grain size, organic content, and stable isotope composition. While macrofaunal densities were similar among habitats sampled at comparable depths, diversity was higher near the hard substrate environments. Discrete communities were present in each habitat type, while annelid functional composition was similar between hard substrate adjacent and canyon axis habitats. Although diversity and abundance of hard substrate adjacent sediment communities did not change with depth, communities were driven by sediments with low organic matter content, whereas canyon and slope community assemblages were best explained by depth and higher organic content. Beta diversity among hard substrate adjacent sediments and canyon axis communities was high, with 27% of canyon taxa and 10% of regional taxa only occurring in hard substrate habitats. Given the thousands of submarine canyons worldwide, our results highlight the overall importance of substrate habitat heterogeneity within canyons in supporting deep-sea benthic diversity and suggest that both within-canyon and regional diversity are underestimated.

Norfolk Canyon↗

USGS2021

A characterization of deep-sea coral and sponge communities along the California and Oregon coast using a remotely operated vehicle on the EXPRESS 2018 expedition

Deep-sea coral and sponge (DSCS) communities serve as essential fish habitats (EFH) by providing shelter and nursery habitat, increasing diversity, and increasing prey availability (Freese and Wing, 2003; Bright, 2007; Baillon et al., 2012; Henderson et al., 2020). Threats to these long-lived, fragile organisms from bottom contact fishing gear, potential offshore renewable energy development, and ocean warming and acidification have increased the need for DSCS research along the U.S. West Coast (Gomez et al., 2018; Salgado et al., 2018; Yoklavich, et al., 2018; Gugliotti et al., 2019). The focus of these studies has varied from species distribution and abundance (Yoklavich and Love, 2005; Tissot et al., 2006) to developing and validating predictive distribution models (Huff et al., 2013; Rooper et al., 2017; Kreidler, 2020) to finding medicinal uses for corals and sponges (Essack et al., 2011; Shrestha et al., 2018). Due to the vast area of unexplored seafloor within the U.S. exclusive economic zone (EEZ; 200 nautical miles off the coast) and the technological requirements and expanse of deep-sea research, there is still much to learn about the distributions and biology of DSCS. This information is critical to resource managers for effective conservation and management of DSCS habitats. Protections are provided by the Pacific Fishery Management Council (PFMC) designation of groundfish EFH conservation areas (EFHCA) and the National Marine Sanctuaries Act (NMSA). Areas designated as EFHCA are closed to bottom trawl fishing to protect and preserve seafloor habitats. Recently the PFMC adopted Amendment 28 to the Groundfish Fishery Management Plan (GFMP; Pacific Fishery Management Council, 2019) which modified EFHCAs by closing new areas identified as vulnerable and reopening areas deemed not vulnerable. The NMSA prohibits bottom disturbance from certain activities within areas designated as national marine sanctuaries, such as oil and gas exploration or extraction, cable laying, and other forms of seabed alteration or construction that disturb benthic communities. NOAA’s Deep-Sea Coral and Research Technology Program (DSCRTP) began a 4-yr funding initiative for the U.S. West Coast in 2017. The goals of the West Coast Deep-Sea Coral Initiative (WCDSCI) were to: 1) gather baseline information on areas subject to fishing regulation changes prior to the implementation of Amendment 28; 2) improve our understanding of known DSCS bycatch “hot spots”; and 3) explore and assess DSCS resources within NOAA National Marine Sanctuaries with emphasis on areas of sanctuary resource protection and management concerns. During the first year of the program, a research cruise was developed to survey the West Coast from Oregon to California studying the DSCS ecosystems in priority areas. The 31-day expedition (9 Oct – 8 Nov, 2018) was launched from the NOAA Ship Bell M. Shimada, beginning in Newport, OR and ending in San Diego, CA. The science team assembled for this cruise were members of the EXpanding Pacific Research and Exploration of Submerged Systems (EXPRESS) campaign, which brings together researchers from federal and nonfederal institutions to collaborate on scientific expeditions targeting the deepwater areas off California, Oregon, and Washington. EXPRESS supports researchers leveraging funding, resources, personnel, and expertise to accomplish more science than would have been possible by a single entity alone. The 2018 coastwide expedition included research partners from National Marine Fisheries Service (NMFS) Southwest Fisheries Science Center (SWFSC) and Northwest Fisheries Science Center (NWFSC), National Ocean Service (Channel Islands, Cordell Bank, Greater Farallones, and Monterey Bay National Marine Sanctuaries), Bureau of Ocean Energy Management (BOEM), U.S. Geological Survey (USGS), and Monterey Bay Aquarium Research Institute (MBARI). Research objectives for the cruise were to: 1) Collect DSCS baseline information at 10 of the EFHCA sites undergoing protection modifications by the Pacific Fishery Management Council. 2) Collect DSCS and fish data at previously unexplored sites within West Coast National Marine Sanctuaries. 3) Revisit a subset of previously surveyed sites to document if changes in DCSC have occurred over time. 4) Collect information to validate BOEM supported cross-shelf habitat suitability models for DSCS. 5) Collect samples to help in identifying (and understanding) West Coast DSCS and expand use of new technologies (ROV, AUV, and environmental DNA [eDNA]). 6) Collect water samples for coastwide eDNA, nutrient, and carbon chemistry studies.

California, Oregon↗

USGS2020

Stable isotope dynamics of herbivorous reef fishes and their ectoparasites

Acanthurids (surgeonfishes) are an abundant and diverse group of herbivorous fishes on coral reefs. While their contribution to trophic linkages and dynamics in coral reef systems has received considerable attention, the role of linkages involving their parasites has not. As both consumers of fish tissue and prey to microcarnivores, external parasites may play a significant role in trophic transfer between primary consumers (and hence their predominantly algae-based diet) and the broader coral reef community. Stable isotope analysis is a common tool for studying trophic linkages which can be used for studies involving parasites. We examined the stable isotope ecology ( 13 C and 15 N) of copepod ( Caligus atromaculatus ) and monogenean ( Neobenedenia sp.) ectoparasites collected from two species of Caribbean acanthurids ( Acanthurus coeruleus and Acanthurus bahianus ). There were significant intraspecific differences in isotope discrimination factors between parasites collected from the two different host species as well as interspecific differences between parasites collected from the same host species. Discrimination factors for 15 N were consistently positive but varied in magnitude depending on host and parasite species and were slightly lower than what would be expected for consumers. The 13 C discrimination factors for both monogeneans and copepods collected from A. coeruleus were consistently positive but were negative for copepods collected from A. bahianus . These findings emphasize the complexity of the stable isotope trophic interactions occurring between parasites and their hosts, highlighting the value of these types of host-parasite isotopic studies.

Diversity↗

USGS2020

Distribution of deep-water scleractinian and stylasterid corals across abiotic environmental gradients on three seamounts in the Anegada Passage

In the Caribbean Basin the distribution and diversity patterns of deep-sea scleractinian corals and stylasterid hydrocorals are poorly known compared to their shallow-water relatives. In this study, we examined species distribution and community assembly patterns of scleractinian and stylasterid corals on three high-profile seamounts within the Anegada Passage, a deep-water throughway linking the Caribbean Sea and western North Atlantic. Using remotely operated vehicle surveys conducted on the E/V Nautilus by the ROV Hercules in 2014, we characterized coral assemblages and seawater environmental variables between 162 and 2,157 m on Dog Seamount, Conrad Seamount, and Noroît Seamount. In all, 13 morphospecies of scleractinian and stylasterid corals were identified from video with stylasterids being numerically more abundant than both colonial and solitary scleractinians. Cosmopolitan framework-forming species including Madrepora oculata and Solenosmilia variabilis were present but occurred in patchy distributions among the three seamounts. Framework-forming species occurred at or above the depth of the aragonite saturation horizon with stylasterid hydrocorals being the only coral taxon observed below Ωarag values of 1. Coral assemblage variation was found to be strongly associated with depth and aragonite saturation state, while other environmental variables exerted less influence. This study enhances our understanding of the factors that regulate scleractinian and stylasterid coral distribution in an underreported marginal sea and establishes a baseline for monitoring future environmental changes due to ocean acidification and deoxygenation in the tropical western Atlantic.

Puerto Rico↗

USGS2020

Submarine canyons influence macrofaunal diversity and density patterns in the deep-sea benthos

Submarine canyons are often morphologically complex features in the deep sea contributing to habitat heterogeneity. In addition, they act as major conduits of organic matter from the shallow productive shelf to the food deprived deep-sea, promoting gradients in food resources and areas of sediment resuspension and deposition. This study focuses on the Baltimore and Norfolk canyons, in the western North Atlantic Ocean, and investigates how different biogeochemical drivers influence canyon and slope macrofaunal communities. Replicated sediment cores were collected along the main axes (~180–1200 m) of Baltimore and Norfolk canyons and at comparable depths on the adjacent slopes. Cores were sorted, assessing whole community macrofaunal (>300 μm) abundance, diversity and standing stocks. Canyon communities were significantly different from slope communities in terms of diversity, abundance patterns and community assemblages, which were attributed to high levels of organic matter enrichment within canyons. There was a significant departure from the expected density-depth relationship in both canyons, driven by enhanced abundances between 800 and 900 m canyon depths, which was characterised as a deposition zone for organic matter. Bathymetric zonation, sediment dynamics, organic enrichment, and disturbance events were clear factors that structured the benthic communities in both Baltimore and Norfolk canyons. Coupling family-level community data, with sediment grain-size and biogeochemistry data explained community dynamics across depth and biogeochemical gradients, providing further evidence that canyons disrupt macrofaunal diversity and density patterns in the deep-sea benthos.

Deep Sea Research Part A, Oceanographic Research P↗

USGS2020

Benthic infaunal communities of Baltimore and Norfolk Canyons

The imperative for finding, cataloging, and understanding continental margin diversity derives from the many key functions, goods and services provided by margin ecosystems and by an increasingly deleterious human footprint on our continental slopes (Levin and Dayton 2009). Progress in seafloor mapping technology and direct observation has revealed unexpected heterogeneity, with a mosaic of habitats and ecosystems linked to geomorphological, geochemical, and hydrographic features that are capable of influencing biotic diversity (Levin and Sibuet 2012). Submarine canyons are dramatic and widespread topographic features crossing continental and island margins in oceans, connecting shelf-margins to deep ocean basins (Harris and Whiteway 2011). Their importance as biodiversity hotspots has continued to emerge over the last two decades as research efforts have increased. Understanding the physical parameters within a canyon system is a primary factor for understanding habitat variability and ecological patterns within the confines of canyon systems (Levin et al. 2001). Margin sediments exhibit ubiquitous depth zonation (Carney et al. 2005), with a diverse suite of species that occupy restricted bathymetric ranges along any given section of the margin. Major shifts in composition among taxa are observed at the shelf-slope transition zone (canyons <500 m), along the upper slope (1,000 m), and at the lower slope transition zone (<3,000 m) (Gibson et al. 2005). In the deep sea, macrofaunal assemblages are generally limited by the availability of allochthonous organic material (Rowe et al. 1982, Billet et al. 1983, Rex et al. 2005, Smith et al. 2008) where macrofaunal densities usually decline with depth and distance from the shore (Rowe et al. 1982, Houston and Haedrich 1984, Rex et al. 2005). However, canyon fauna can experience enhanced food supply through the resuspension and deposition of organic-rich sediments, delivered by increased current velocities within the confines of the canyon (Rowe 1971, Shepard et al. 1974). As a result, canyons are often reported as sustaining enhanced abundances and biomass compared with nearby open slope habitats at similar depths (Vetter and Dayton 1998, Duineveld et al. 2001, De Leo et al. 2010) as well as enhancing regional (γ) and local (α) biodiversity (Hecker et al. 1983, Vetter and Dayton 1998, De Leo et al. 2010, Vetter et al. 2010). Furthermore, enhanced habitat heterogeneity can also be a major structuring agent of ecological assemblages, promoting beta (β) diversity (McClain and Barry 2010) in canyon environments. Canyon systems have often been described as biodiversity hotspots, especially at mid-slope depths (Levin and Sibuet 2012) where physical processes, characterized by complex patterns in hydrography, promote topographically induced upwelling, enhanced mixing via internal tides, and the focusing of tidal bores (Vetter and Dayton 1998, Cacchione et al. 2002). Additionally, sediment transport and accumulation (García et al. 2008) represent important influential ecological drivers. Factors such as substrata heterogeneity (Levin and Sibuet 2012) and concentration of organic matter (De Leo et al. 2010) have been suggested to explain higher faunal diversity, abundance, and benthic productivity found in canyon systems compared with surrounding areas. Bathymetric patterns of species diversity have been attributed to changes in sediment characteristics (Etter and Grassle 1992), productivity, currents, oxygen, disturbance, and the interplay of biotic effects with depth and latitude (Levin et al. 2001, Carney et al. 2005). Recent studies report on the uniqueness of canyon benthic communities and habitats and the view that no two canyons are alike (Cunha et al. 2011). Certain submarine canyons may maintain 436 characteristic and unique faunas, but more often canyon macrofaunal assemblages show high dominance and locally reduced biodiversity (Rowe 1971, Gage 1997, Curdia et al. 2004, Cun

Baltimore Canyon, Norfolk Canyon↗