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M. Smith

Bio: M. Smith is an academic researcher from Gulf of Mexico Foundation. The author has contributed to research in topics: Brine pool. The author has an hindex of 1, co-authored 1 publications receiving 11 citations.
Topics: Brine pool

Papers
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Journal ArticleDOI
TL;DR: In this article, the authors collected from ROV JASON III on randomized transects (generally 10 per site) was used to compare seven suspected hydrocarbon seeps on the lower continental slope at depths of 956 to 2330 m.
Abstract: Photographic sampling collected from ROV JASON III on randomized transects (generally 10 per site) was used to compare seven suspected hydrocarbon seeps on the lower continental slope at depths of 956 to 2330 m. The study design focused on areas containing high-amplitude reflectance patterns in seismic returns from the bottom. Animal samples nested in these areas and high-resolution photographic mosaics permitted fine-scale description of the community components and their associations with each other. The transect results showed three types of chemosynthetic community: carbonate prone, brine pool prone, and low-density. These communities are characterized by, respectively, abundant carbonate rubble and tubeworm clusters, bacterial mats and brine pools, and relatively sparse chemosynthetic fauna that tended to be overlooked by the photographic survey plan. These differences were not clearly related to depth or longitude because the sites are at the opposite eastern and western extents of the project region. Photographic survey is a statistically reliable method for detecting the carbonate rubble and bacterial mat types of community, but may be unreliable for sparse or clustered fauna such as seep mussels. Photographic survey results provided relatively low taxonomic resolution, but were sufficient to distinguish statistical differences in the abundance of characteristic faunal groups, such as the Echinoidea and Gorgonacea, associated with hydrocarbon seeps. Initial studies of statistical power indicate that future photographic surveys of suspected seep communities, if conducted with an equivalent level of effort, might detect the presence of more abundant habitat, including carbonate rubble, bacterial mats, and tubeworms, but could miss less abundant indicators.

11 citations


Cited by
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Journal ArticleDOI
TL;DR: Authigenic carbonates from hydrocarbon seeps are unique long-term archives of past fluid flow and are used to assess the evolution of seep activity and potential driving forces.

29 citations

Journal ArticleDOI
TL;DR: Video analysis of the Makapu'u deep-sea coral bed yields new insight on the spatial ecology of seamounts, pointing out that community changes can occur over narrow depth ranges and that communities can be structured by small-scale physiography.
Abstract: Seamounts are largely unexplored undersea mountains rising abruptly from the ocean floor, which can support an increased abundance and diversity of organisms. Deep-sea corals are important benthic structure-formers on current-swept hard substrates in these habitats. While depth is emerging as a factor structuring the fauna of seamounts on a large spatial scale, most work addressing deep-sea coral and seamount community structure has not considered the role of small-scale variation in species distributions. Video from six ROV dives over a depth range of ~320–530 m were analyzed to assess the diversity and density of benthic megafaunal invertebrates across the Makapu'u deep-sea coral bed, offshore of Oahu, Hawaii. At the same time, the physical environment along the dive track was surveyed to relate biotic patterns with abiotic variables including depth, aspect, rugosity, substrate, slope and relief to test the factors structuring community assemblages. Despite the narrow range examined, depth was found to be the strongest structuring gradient, and six unique macrobenthic communities were found, with a 93% faunal dissimilarity over the depth surveyed. Relief, rugosity and slope were also factors in the final model. Alcyonacean octocorals were the dominant macrofaunal invertebrates at all but the deepest depth zone. The commercially harvested precious coral C. secundum was the dominant species at depths 370–470 m, with a distribution that is on average deeper than similar areas. This may be artificial due to the past harvesting of this species on the shallower portion of its range. Primnoid octocorals were the most abundant octocoral family overall. This work yields new insight on the spatial ecology of seamounts, pointing out that community changes can occur over narrow depth ranges and that communities can be structured by small-scale physiography.

27 citations

Journal ArticleDOI
TL;DR: This work describes hypersaline environments potentially or likely to become contaminated with hydrocarbons, including perennial and transient environments above and below ground, and discusses what is known about the microbes degrading hydroCarbons and the extent of their activities.

25 citations

Journal ArticleDOI
TL;DR: In the Arctic Ocean, cold seep communities are characterized by a lack of large specialized chemo-obligate polychaetes and molluscs often seen at non-Arctic seeps, but nonetheless have substantially higher benthic abundance and biomass compared to adjacent areas lacking seeps as discussed by the authors.
Abstract: Cold-seep benthic communities in the Arctic exist at the nexus of two extreme environments; one reflecting the harsh physical extremes of the Arctic environment, and another reflecting chemical extremes and strong environmental gradients associated with seafloor seepage of methane and toxic sulfide enriched sediments. Recent ecological investigations of cold seeps at numerous locations on the margins of the Arctic Ocean basin reveal that seabed seepage of reduced gas and fluids strongly influence benthic communities and associated marine ecosystems. These Arctic seep communities are mostly different from both conventional Arctic benthic communities as well as cold-seep systems elsewhere in the world. They are characterized by a lack of large specialized chemo-obligate polychaetes and molluscs often seen at non-Arctic seeps, but nonetheless have substantially higher benthic abundance and biomass compared to adjacent Arctic areas lacking seeps. Arctic seep communities are dominated by expansive tufts or meadows of siboglinid polychaetes, which can reach densities up to >3x10^5 ind.m-2. The enhanced authochthonous chemosynthetic production, combined with reef-like structures from methane-derived authigenic carbonates, provides a rich and complex local habitat that results in aggregations of non-seep specialized fauna from multiple trophic levels, including several commercial species. Seeps are far more widespread in the Arctic than thought even a few years ago. They exhibit in situ benthic chemosynthetic production cycles that operate on different spatial and temporal cycles than the sunlight driven counterpart of photosynthetic production in the ocean’s surface. These systems can act as a spatio-temporal bridge for benthic communities and associated ecosystems that may otherwise suffer from a lack of consistency in food quality from the surface ocean during seasons of low production. As climate change impacts accelerate in Arctic marginal seas, photosynthetic primary production cycles are being modified, including in terms of changes in the timing, magnitude, and quality of photosynthetic carbon, whose delivery to the seabed fuels benthic communities. Furthermore, an increased northward expansion of species is expected as a consequence of warming seas. This may have implications for dispersal and evolution of both chemosymbiotic species as well as for background taxa in the entire realm of the Arctic and fringing seas.

25 citations

Journal ArticleDOI
TL;DR: In this paper, the authors combined published values for methane fluxes with data collected across various scales and resolutions to compile a methane budget for Green Canyon (GC) 600 in the Northern Gulf of Mexico.

18 citations