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Southeastern US Marine Ecosystems and Hydrocarbon Exploration
- 1. SOUTHEASTERN US MARINESOUTHEASTERN US MARINE ECOSYSTEMS ANDECOSYSTEMS AND HYDROCARBON EXPLORATIONHYDROCARBON EXPLORATION Steve W.Steve W. RossRoss
- 2. SEUS MarineSEUS Marine EcosystemsEcosystems • Large estuaries and numerous rivers • Long coastlines, inshore and offshore • Extremely high marine and estuarine biodiversity (> 1000 spp. of fishes < 200 m, more than anywhere else in US except FL) Moderate climate Temperate latitudes (warm and cool temperate with subtropical input Habitat diversity high (shallow and deep) Gulf Stream (nutrient dynamics, temperature modulation, transport)
- 3. Manteo Prospect Hatteras Middle Slope (“The Point”) Since the late 1980s to early 1990s, there has been substantial progress in understanding offshore ecology. Even so, the farther offshore we go, the less we know, and in some cases there are almost complete knowledge gaps. 500 m 1000 m • Dynamic oceanography • Rugged terrain • High carbon deposition • High infaunal biomass • Unusual communities • High productivity and biological activity
- 4. Depths in meters Muds and canyons north of Cape Hatteras Hard grounds and carbonate sands south of Cape Hatteras A virtual data desert beyond 2000 m, esp. for benthic ecology & biology
- 5. Gulf Stream dominates regional oceanography. Influences: •Weather/climate •zoogeography •genetic connectivity •nutrient delivery to shelf via upwelling •Designated as EFH Sargassso Sea
- 6. Spawning migration Juvenile recruitment Estuarine-dependent species: Atlantic croaker Atlantic menhaden Gulf flounder Spot Silver perch Spring Fall Winter Summer Juvenile recruitment Spawning migration Anadromous species: American shad Blueback herring Hickory shad Striped bass Atlantic sturgeon Catadromous species: American eel Spawning migration Juvenile recruitment Reef-associated species: Snapper/grouper Juvenile recruitment Freshwater Estuaries Nearshore Offshore Michel 2011 Great connectivity between river/estuarine and offshore systems But less connectivity with deeper (> 200 m) waters Takes place generally inshore of 200 m Big issues facing these resources are degraded habitat and overfishing (by catch issues).
- 7. Demersal fishes Catch(milliontonnes) 0 2000 4000 6000 8000 10000 12000 Pelagic fishes 0 8000 16000 24000 32000 40000 48000 0 500 1000 Reef associated fishes and flatfishes Year 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 0 1000 2000 3000 4000 5000 6000 Flatfishes All fishes 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 0 15000 30000 45000 60000 75000 90000 105000 120000 135000 Regional commercial fish landings. The great majority of these are caught in shelf depths. There are few current fisheries deeper than 200 m (exceptions = wreckfish, offshore pelagics) (Michele 2011, www.seaaroundus.org)
- 8. This example of detailed estuarine and nearshore habitat mapping is typical of many states. This level of detail or precision is very rare offshore. Ecological knowledge declines rapidly with increasing distance offshore. after Deaton et al. 2010
- 10. South Atlantic Bight Marine Assessment Benthic Habitat Hardbottom Anderson et al. (in review 2015) Shelf (<200 m) Hardbottom •Dominant resources = snapper, grouper, porgy complex & other reef fishes •Invertebrate fauna very rich but poorly studied •Reefs support diverse subtropical communities •Designated as EFH •Overfishing & habitat degradation are issues. Do the 6 shelf edge MPAs offer sufficient protection?
- 11. Sedberry et al. (2006) Blackbelly rosefish Snowy grouper Most data < 200 m)
- 12. Deep-sea (> 300m) Coral Habitats • Banks scattered, but common on SEUS slope (370- 800 m), also on rocks and in canyons • Very rugged topography (30-100 m tall mounds) • High species richness, high numbers of species new to science and new to region • Provide shelter, feeding areas, and possibly spawning areas to many species • Support commercial & potentially commercial spp. • Influenced by Gulf Stream dynamics, large environmental variations
- 13. Environmental data (2 Dec 09 – 16 May 10) from lander deployed at deep coral mounds off Cape Lookout, NC (430 m). Note Gulf Stream intrusions on bottom (Temp & other spikes). Gulf of Mexico 425 m
- 14. Gulf Stream Loop Current More deep-sea heterogeneity than expected Deep Reef & Canyon Study Areas (groupings based on fish communities) Genetic discontinuity also displayed by L. pertusa deep corals: GOM differs from SEUS
- 15. South Atlantic Fishery Management Council created 4 deep coral HAPCs (23,000 sq. miles) that protect most deep coral habitat off the SEUS. The largest protected area off the continental US.
- 16. Off Cape Hatteras Pelagic to Mesopelagic Environment: •Important fisheries (billfishes, sharks, dolphin, mackerels, tunas) •Highly migratory species •Charismatic & endangered species (mammals, turtles, seabirds, whale sharks) •Mesopelagic may have greatest abundance & biomass of any marine habitat •Role of mesopelagic fauna in carbon movement probably far underestimated •Important conduit for larval movement •Surface to mid-depth is area of likely spill impacts (as in DWH) •Important nursery and feeding habitats (Sargassum) At least 80 fish species use Sargassum (Casazza & Ross 2008)
- 17. NE FACING SLOPE TOP WEST FACING SLOPE ¯ ¯ Cape Fear coral mound 3-D view Cape Fear Bank Baltimore Canyon
- 18. Areas recently (2006- ) mapped with high detail, high precision multibeam sonar Mapped boxes are only 4.4% of the two planning areas.
- 19. RESEARCH TORESEARCH TO CONSIDERCONSIDER • Severe lack of biological data > 200 m (benthic & mesopelagic)Severe lack of biological data > 200 m (benthic & mesopelagic) • Multibeam mapping of interest/target areasMultibeam mapping of interest/target areas – Strong need for better habitat descriptionsStrong need for better habitat descriptions • Trophodynamic studies (most bang per $$)Trophodynamic studies (most bang per $$) – Complete unfinished studies, add othersComplete unfinished studies, add others • Interaction of physical oceanography and biologyInteraction of physical oceanography and biology – larval transport, genetic continuity, dispersal barriers orlarval transport, genetic continuity, dispersal barriers or conduitsconduits • Population structure & connectivity studiesPopulation structure & connectivity studies • Marine larvae dynamicsMarine larvae dynamics – distributions, seasonality, movementsdistributions, seasonality, movements • Locate ocean spawning areas for important speciesLocate ocean spawning areas for important species
Hinweis der Redaktion
- Viosca Knoll area of Gulf of Mexico This talk will focus on a few high points concerning regional offshore ecology and will provide some update on what we have learned in recent years.
- 26 years ago
- Canyon province north of Hatteras and Carbonate-Blake Plateau province south of Hatteras.
- Surface currents as high as 5 kts and 3 kts common
- In addition there is seasonal north-south movement. What about beyond 200 m?
- Habitat is key to fishery production.
- Located in area of extensive coral mounds. These types of long term, intensive data are limited in deep-sea research & usually collected for oceanographic purposes rather than biological. Such events would be very difficult to detect using opportunistic sampling from a ship. Moorings could be used but have more instrument restrictions, instruments not at same depth, and are not as stable.
- Basically the water column above the bottom to the surface.