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Sample records for address mid-atlantic fishery

  1. 76 FR 66041 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-25

    ... National Oceanic and Atmospheric Administration RIN 0648-XA786 Mid-Atlantic Fishery Management Council... Fishery Management Council's (Council) Ecosystem and Ocean Planning Committee will hold a public meeting... telephone: (410) 859- 3300. Council address: Mid-Atlantic Fishery Management Council, 800 N. State...

  2. 77 FR 65364 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-26

    ... Fishery Management Council (Council) Staff will convene a meeting of the Visioning and Strategic Planning... National Oceanic and Atmospheric Administration RIN 0648-XC316 Mid-Atlantic Fishery Management Council..., Baltimore, MD 21240; telephone: (410) 859-3300. Council address: Mid-Atlantic Fishery Management...

  3. 78 FR 48421 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-08

    ... Fishery Management Council's Spiny Dogfish Advisory Panel (AP) will meet to develop a Fishery Performance Report for the Spiny Dogfish fishery in preparation for the Council and the Council's Scientific and... link: http://mafmc.adobeconnect.com/dogfish/ Council address: Mid-Atlantic Fishery Management...

  4. 76 FR 56742 - Mid-Atlantic Fishery Management Council; Workshop

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-14

    ... National Oceanic and Atmospheric Administration RIN 0648-XA700 Mid-Atlantic Fishery Management Council... (NOAA), Commerce. ACTION: Notice of a workshop. SUMMARY: The Eight Regional Fishery Management Councils... Ecosystems Based Fishery Management (EBFM) issues from biological, economic and social perspectives....

  5. 76 FR 69706 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-09

    ..., Black Sea Bass Monitoring Committee, and the Mid-Atlantic Fishery Council's and the Atlantic States Marine Fisheries Commission's Summer Flounder, Scup, and Black Sea Bass Advisors will hold public... meeting agenda. ADDRESSES: The Summer Flounder, Scup, and Black Sea Bass Monitoring Committee...

  6. 75 FR 26922 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-13

    ... National Oceanic and Atmospheric Administration RIN 0648-XW41 Mid-Atlantic Fishery Management Council... Administration (NOAA), Commerce. ACTION: Notice of a public meeting. SUMMARY: The Mid-Atlantic Fishery Management... at the Mid-Atlantic Fishery Management Council, 800 N. State Street, Suite 201, Dover, DE...

  7. 78 FR 55063 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-09

    ... Atmospheric Administration (NOAA), Commerce. ACTION: Notice of public meeting. SUMMARY: The Spiny Dogfish... address below. Webinar link: http://mafmc.adobeconnect.com/dogfish/ Council address: Mid-Atlantic Fishery...: The Spiny Dogfish Monitoring Committee will review the annual catch target (ACT) and other...

  8. 77 FR 51968 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-28

    ... National Oceanic and Atmospheric Administration RIN 0648-XC188 Mid-Atlantic Fishery Management Council; Public Meeting AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION: Notice of a public meeting. SUMMARY: The Mid-Atlantic Fishery...

  9. 75 FR 4348 - Mid-Atlantic Fishery Management Council; Public Hearings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ... National Oceanic and Atmospheric Administration RIN 0648-XU05 Mid-Atlantic Fishery Management Council... Administration (NOAA), Commerce. ACTION: Notice of public hearings. SUMMARY: The Mid-Atlantic Fishery Management... Atlantic Mackerel, Squid, and Butterfish (MSB) Fishery Management Plan (FMP). See SUPPLEMENTARY...

  10. 78 FR 50395 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-19

    ... National Oceanic and Atmospheric Administration RIN 0648-XC814 Mid-Atlantic Fishery Management Council; Public Meeting AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION: Notice of a public meeting. SUMMARY: The Mid-Atlantic Fishery...

  11. 77 FR 65363 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-26

    ... National Oceanic and Atmospheric Administration RIN 0648-XC298 Mid-Atlantic Fishery Management Council; Public Meeting AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION: Notice of a public meeting. SUMMARY: The Mid-Atlantic Fishery...

  12. 77 FR 77036 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-31

    ... National Oceanic and Atmospheric Administration RIN 0648-XC421 Mid-Atlantic Fishery Management Council... Administration (NOAA), Commerce. ACTION: Notice of a public meeting. SUMMARY: The Mid-Atlantic Fishery Management... options for improving the management of the longfin and Illex squid fisheries, with a focus on...

  13. 76 FR 16617 - Mid-Atlantic Fishery Management Council (MAFMC); Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-24

    ... National Oceanic and Atmospheric Administration RIN 0648-XA315 Mid-Atlantic Fishery Management Council... Administration (NOAA), Commerce. ACTION: Notice of public meeting. SUMMARY: The Mid-Atlantic Fishery Management... Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE) Presentation from 10 a.m. until...

  14. 78 FR 20897 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-08

    .... Moore Ph.D., Executive Director, Mid-Atlantic Fishery Management Council, 800 N. State Street, Suite 201... protocol will be used to monitor and regulate ITQ ownership and lease activity in these fisheries....

  15. 75 FR 38464 - Mid-Atlantic Fishery Management Council; Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-02

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE...; Public Meetings AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION: Notice of public meetings. SUMMARY: The Mid-Atlantic Fishery...

  16. WATERSHED RESTORATION AND FISHERIES MANAGEMENT IN THE MID-ATLANTIC HIGHLANDS

    EPA Science Inventory

    This presentation is about watershed restoration and fisheries management in the Mid-Atlantic Highlands. The goal of the Canaan Valley Institue is to develop and implement solutions to restore damaged areas and protect aquatic systems in the Mid-Atlantic Highlands. A decision ana...

  17. 50 CFR 648.21 - Mid-Atlantic Fishery Management Council risk policy.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Mid-Atlantic Fishery Management Council risk policy. 648.21 Section 648.21 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE NORTHEASTERN UNITED...

  18. 75 FR 20984 - Mid-Atlantic Fishery Management Council (MAFMC); Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-22

    ...; telephone: (302) 674-2331. FOR FURTHER INFORMATION CONTACT: Daniel T. Furlong, Executive Director, Mid... comments on or before 5:00 p.m., EDT, on May 21, 2010 to Daniel T. Furlong, Mid-Atlantic Fishery...

  19. 77 FR 12010 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-28

    .... SUMMARY: The Mid-Atlantic Fishery Management Council's (Council) Ad-Hoc Atlantic Sturgeon Committee will... the Federal Register on February 17, 2012 (77 FR 9628). The date of the meeting changed from March...

  20. 78 FR 30869 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-23

    ...The Mid-Atlantic Fishery Management Council (Council) and its Research Set-Aside Committee, its Mackerel, Squid, Butterfish Committee, its Surfclam and Ocean Quahog Committee, and its Executive Committee will hold public...

  1. 75 FR 8673 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-25

    ...The Mid-Atlantic Fishery Management Council (Council) will conduct an educational workshop on catch shares in cooperation with the Fisheries Leadership and Sustainability Forum (FLSF), the Atlantic States Marine Fisheries Commission (ASMFC), and the National Marine Fisheries Service (NMFS). The intent of this workshop is to share information and concerns about the use of catch shares by the......

  2. 78 FR 52135 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-22

    .... SUPPLEMENTARY INFORMATION: The original notice published in the Federal Register on August 8, 2013 (78 FR 48421.... SUMMARY: The Mid-Atlantic Fishery Management Council's (Council) Spiny Dogfish Advisory Panel (AP) will meet to develop a Fishery Performance Report for the Spiny Dogfish fishery in preparation for...

  3. 76 FR 3878 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-21

    ...; Public Meeting AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION: Notice of a public meeting. SUMMARY: The Mid-Atlantic Fishery Management... bottom trawl survey in relation to the SSC's ABC recommendation for butterfish for the 2011 fishing...

  4. 76 FR 54739 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-02

    ... Statistical Committee (SSC) and the Spiny Dogfish Monitoring Committee of the Mid-Atlantic Fishery Management.... until 5 p.m. and Thursday, September 22 from 8 a.m. until 5 p.m. The Spiny Dogfish Monitoring Committee... recommendations for spiny dogfish; special session for social/economics issues; review MAFMC five-year...

  5. 77 FR 54566 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-05

    ...The Mid-Atlantic Fishery Management Council (Council) Staff will hold the second meeting of the Visioning and Strategic Planning Working Group. During this meeting, the group will finalize draft vision and mission statements, perform an abridged analysis of the Council's strengths, weaknesses, opportunities, and threats, and develop a goal structure for the strategic...

  6. 77 FR 76473 - Mid-Atlantic Fishery Management Council; Public Hearings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-28

    ... National Oceanic and Atmospheric Administration RIN 0648-XC416 Mid-Atlantic Fishery Management Council... Council (Council) will hold public hearings on January 15, 16, and 17, 2013 to allow for public input on... (chronologically) in Ocean City, MD; Lewes, DE; and Toms River, NJ. Written comments should be mailed to...

  7. 75 FR 20984 - Mid-Atlantic Fishery Management Council (MAFMC); Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-22

    ... Council's (MAFMC) Ad Hoc Search Committee will hold a closed meeting. DATES: Monday, May 10, 2010 from 9 a... INFORMATION: The Mid-Atlantic Council is currently seeking a new Executive Director. The Ad Hoc...

  8. 77 FR 49782 - Mid-Atlantic Fishery Management Council (MAFMC); Public Hearings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-17

    ... Council (Council) will hold public hearings to allow for public input on Amendment 3 to the Spiny Dogfish... Council at the address below or at http://www.mafmc.org/fmp/dogfish/dogfish.htm . Council address: Mid... four management issues related to management of the spiny dogfish fishery in Atlantic federal...

  9. Mid-Atlantic Region: A Report Identifying and Addressing the Educational Needs

    ERIC Educational Resources Information Center

    US Department of Education, 2011

    2011-01-01

    This report presents the deliberations of the Mid-Atlantic Regional Advisory Committee (RAC), one of 10 RACs established under the Educational Technical Assistance Act of 2002 (20 U.S.C. sections 9601 et. seq.) to assess the educational needs of the region. The committee's report outlines the educational needs across the District of Columbia and…

  10. 75 FR 25843 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-10

    ... Council's (MAFMC) Squid, Mackerel, and Butterfish Committee will hold a public meeting that also includes the Squid, Mackerel, and Butterfish Advisory Panel as well as the Amendment 11 Fishery Management... this meeting is to address outstanding issues within Amendment 11 to the Atlantic Mackerel, Squid,...

  11. 75 FR 29725 - Mid-Atlantic Fishery Management Council; Public Hearings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-27

    ... herrings (blueback and alewife) and shads (American and hickory) in the MSB fisheries, especially given the... herrings. Related to the above concerns, this amendment may address one or more of the following issues: (1... monitoring in order to determine the significance of river herring and shad incidental catch in the...

  12. 78 FR 19216 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-29

    ... of the workshop is to facilitate development of spatial alternatives for deep sea coral protection... address the need for a refined set of deep sea coral protection area options for inclusion in Amendment 16 to the Mackerel, Squid, and Butterfish Fishery Management Plan (Protections for Deep Sea Corals)....

  13. 77 FR 30507 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-23

    ... Fishery Management Council's (Council) Mackerel, Squid, and Butterfish Committee and Mackerel, Squid, and... Atlantic Mackerel, Squid, and Butterfish Fishery Management Plan, review public comments received, and...

  14. 75 FR 8923 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-26

    ... Fishery Management Council (MAFMC) and the New England Fishery Management Council's Joint Spiny Dogfish... updates to spiny dogfish stock status that occurred through the recent Transboundary Resource...

  15. 50 CFR 648.20 - Mid-Atlantic Fishery Management Council ABC control rules.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... biology of the stock, fisheries that exploit the stock, and data collection methods; (iv) The stock... SSC to determine the following: (i) Key features of the stock biology, the fisheries that exploit...

  16. 50 CFR 648.20 - Mid-Atlantic Fishery Management Council ABC control rules.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... biology of the stock, fisheries that exploit the stock, and data collection methods; (iv) The stock... SSC to determine the following: (i) Key features of the stock biology, the fisheries that exploit...

  17. 50 CFR 648.20 - Mid-Atlantic Fishery Management Council ABC control rules.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... biology of the stock, fisheries that exploit the stock, and data collection methods; (iv) The stock... SSC to determine the following: (i) Key features of the stock biology, the fisheries that exploit...

  18. 77 FR 2961 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-20

    ... Fishery Management Council's (Council) Tilefish Advisory Panel (AP) will meet with the Council's Social.... SUPPLEMENTARY INFORMATION: The purpose of this meeting is to review fishery performance and create an AP...

  19. 77 FR 52315 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-29

    ... acceptable biological catch (ABC) and also whether the catch cap of butterfish for the longfin squid fishery should be altered to be a discard cap on the longfin squid fishery. This meeting would constitute..., Squid, and Butterfish Fishery Management Plan.'' The second framework meeting would be at the...

  20. 78 FR 19215 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-29

    ..., Squid, and Butterfish (MSB) Advisory Panel (AP) will meet to develop Fishery Performance Reports for the Atlantic Mackerel, Squid, and Butterfish fisheries in preparation for the Council's setting of... purpose of the meeting is to create Fishery Performance Reports by the Council's Atlantic Mackerel,...

  1. 78 FR 53132 - Mid-Atlantic Fishery Management Council (MAFMC); Meeting; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-28

    ... published at 78 FR 48421, August 8, 2013, and the correction to the meeting time published at 78 FR 52135...-Atlantic Fishery Management Council's Spiny Dogfish Advisory Panel (AP) will meet to develop a Fishery Performance Report for the Spiny Dogfish fishery in preparation for the Council and the Council's...

  2. 76 FR 27019 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-10

    ... Fishery Management Council's (Council) Squid, Mackerel, Butterfish Monitoring Committee will hold a public... management of Atlantic mackerel, butterfish, Loligo and Illex Squids for 2012, including annual catch...

  3. 77 FR 29316 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-17

    ... Fishery Management Council's Mackerel, Squid, and Butterfish (MSB) Monitoring Committee will hold a public... management of Atlantic mackerel, butterfish, longfin (Loligo) squid, and Illex Squid for 2013,...

  4. 78 FR 52508 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-23

    ... Council's (Council) Mackerel, Squid, and Butterfish Advisory Panel (AP) will meet to develop... restricted in coming years. The small-mesh whiting and squid fisheries have bycatch of Georges Bank... small-mesh measures are likely to affect both the whiting and squid fisheries. The goal of the...

  5. 77 FR 9628 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-17

    ... Fishery Management Council's (Council) Ad-Hoc Atlantic Sturgeon Committee will hold a meeting. DATES: The... potential management actions to minimize incidental catches of Atlantic sturgeon in fisheries managed by the... sturgeon under the Endangered Species Act. Although non-emergency issues not contained in this agenda...

  6. 76 FR 70421 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-14

    ... management measures for the recreational summer flounder, scup, and black sea bass fisheries. DATES: The meeting will begin on Friday, December 2, 2011 at 1 p.m. and will end on Saturday, December 3, 2011 no... on the summer flounder, scup, and black sea bass fishery, and; (3) How the Council can work...

  7. 76 FR 56735 - Mid-Atlantic Fishery Management Council (MAFMC); Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-14

    ... Council's Squid, Mackerel, Butterfish Advisory Panel will hold a public meeting. DATES: The meeting will... will develop recommendations for the Council regarding Amendment 14 to the Atlantic Mackerel, Squid... Atlantic mackerel, squid, and butterfish fisheries. Special Accommodations The meeting is...

  8. 75 FR 26921 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-13

    ... Fishery Management Council's (MAFMC) Joint Spiny Dogfish Committee and Advisory Panel will hold a meeting... for inclusion in Amendment 3 to the Spiny Dogfish FMP. Details concerning participation on the...

  9. 77 FR 52695 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-30

    ... Council's (Council) Spiny Dogfish Advisory Panel (AP) will meet in Philadelphia, PA. DATES: The meeting... performance and create an AP Fishery Performance Report for Spiny Dogfish. Although non-emergency issues...

  10. 75 FR 14428 - Mid-Atlantic Fishery Management Council (MAFMC); Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-25

    ... Fishery Management Plans (FMPs). From 11 a.m. until Noon, the Council will consider, discuss and possibly... on the status of the Council's FMPs. The Council will review the Monkfish Advisory Panel and...

  11. 77 FR 65867 - Mid-Atlantic Fishery Management Council; Public Hearings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-31

    ...; Public Hearings AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric.... Scoping hearings will be held on the following dates: Nov 14, 2012, 6 p.m.-8 p.m.: Internet Webinar: https... be made in writing, electronically, or during the scoping hearings as described above. If the...

  12. 78 FR 44539 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-24

    ... Fishery Management Council (Council) and its Research Set-Aside Committee (RSA), and its Ecosystems and.... SUPPLEMENTARY INFORMATION: Tuesday, August 13, 2013 1 p.m. until 3 p.m.--The RSA Committee will meet. 3 p.m... the Council's Committees and the Council itself are: Tuesday, August 13, 2013 The RSA Committee...

  13. 77 FR 23662 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-20

    ... (SSC) will meet with the Council's Atlantic Mackerel, Squid, and Butterfish Advisory Panel (AP). The purpose of the meeting is to develop Fishery Performance Reports for the Atlantic Mackerel, Squid, and... Mackerel, Squid, and Butterfish Advisory Panel (AP). The intent of these reports is to facilitate a...

  14. 77 FR 31332 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-25

    ... Research Methodology (SBRM) presentation will be held from 10 a.m. until 10:30 a.m. The Council will hold... Fishery Management Council (Council) and its Research Set-Aside Committee, Mackerel, Squid, and Butterfish...; telephone: (302) 526-5255. SUPPLEMENTARY INFORMATION: Monday, June 11, 2012 The Research Set-Aside...

  15. 78 FR 52505 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-23

    ... Council's (MAFMC) Bluefish Monitoring Committee and Summer Flounder, Scup, and Black Sea Bass Monitoring..., Scup, and Black Sea Bass Monitoring Committee will meet on September 19 to discuss and recommend 2014..., scup, and black sea bass fisheries. Multi-year ACTs and management measures, applicable to...

  16. 76 FR 41767 - Mid-Atlantic Fishery Management Council (MAFMC); Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-15

    ... Bass, and Bluefish Industry Advisory Panels will hold public meetings. DATES: The meeting will be held...) 674-2331, extension 255. SUPPLEMENTARY INFORMATION: The Scup, Black Sea Bass, Summer Flounder, and... to achieve ACTs for the summer flounder, scup, black sea bass, and bluefish fisheries. Scup...

  17. 75 FR 66072 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-27

    ... Council's (MAFMC) Summer Flounder Monitoring Committee, Scup Monitoring Committee, Black Sea Bass... Commission's Sumer Flounder, Scup, and Black Sea Bass Advisors will hold public meetings. DATES: The meeting... sea bass fisheries. Although non-emergency issues not contained in this agenda may come before...

  18. 77 FR 59593 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-28

    ... Fishery Management Council (Council), its Visioning and Strategic Planning Working Group, and Spiny...: The meetings will be held at the Ocean Place, One Ocean Blvd., Long Branch, NJ 07740; telephone: (732... INFORMATION: Monday, October 15, 2012 1 p.m. until 5 p.m.--The Visioning and Strategic Planning Working...

  19. 75 FR 11129 - Mid-Atlantic Fishery Management Council; Atlantic Mackerel, Butterfish, Atlantic Bluefish, Spiny...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-10

    ... alternative measures to address the new Magnuson-Stevens Act requirements for ACLs and AMs (74 FR 12314). The..., tilefish, surfclams, and ocean quahogs. This supplemental notice is to alert the interested public of...

  20. 77 FR 44216 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-27

    ... reports, receive Organizational Reports, Executive Director's Report, Science Report, Committee Reports... windowpane flounder, the Executive Director's Report, the Science Report, Committee Reports, and conduct any... action to address the emergency. Special Accommodations This meeting is physically accessible to...

  1. 75 FR 35768 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-23

    ... Council's (MAFMC) Scientific and Statistical Committee (SSC) and Summer Flounder, Scup, Black Sea Bass... held on Tuesday, July 13, 2010, from 8:30 a.m. to 12 p.m. ADDRESSES: The webinar will be held at the..., Black Sea Bass, and Bluefish Monitoring Committee's will meet to discuss the 2010 stock...

  2. 77 FR 47820 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-10

    ... entitled ``Modeling Protogynous Hermaphrodite Fishes.'' DATES: The workshop will be held on Wednesday...: This workshop will address the need for improved stock assessment approaches for protogynous fish, by... current and innovative methods for assessing protogynous fish, and to discuss data needs and...

  3. 75 FR 57262 - New England and Mid-Atlantic Fishery Management Councils; Amendment 5 to the Monkfish Fishery...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-20

    ... FR 7880). The Magnuson-Stevens Act also required that the ACLs and AMs be adopted by 2011. During the... supplemental notice is to alert the interested public of the New ] England Fishery Management...

  4. Mid-Atlantic Regional Wind Energy Institute

    SciTech Connect

    Courtney Lane

    2011-12-20

    As the Department of Energy stated in its 20% Wind Energy by 2030 report, there will need to be enhanced outreach efforts on a national, state, regional, and local level to communicate wind development opportunities, benefits and challenges to a diverse set of stakeholders. To help address this need, PennFuture was awarded funding to create the Mid-Atlantic Regional Wind Energy Institute to provide general education and outreach on wind energy development across Maryland, Virginia, Delaware, Pennsylvania and West Virginia. Over the course of the two-year grant period, PennFuture used its expertise on wind energy policy and development in Pennsylvania and expanded it to other states in the Mid-Atlantic region. PennFuture accomplished this through reaching out and establishing connections with policy makers, local environmental groups, health and economic development organizations, and educational institutions and wind energy developers throughout the Mid-Atlantic region. PennFuture conducted two regional wind educational forums that brought together wind industry representatives and public interest organizations from across the region to discuss and address wind development in the Mid-Atlantic region. PennFuture developed the agenda and speakers in collaboration with experts on the ground in each state to help determine the critical issue to wind energy in each location. The sessions focused on topics ranging from the basics of wind development; model ordinance and tax issues; anti-wind arguments and counter points; wildlife issues and coalition building. In addition to in-person events, PennFuture held three webinars on (1) Generating Jobs with Wind Energy; (2) Reviving American Manufacturing with Wind Power; and (3) Wind and Transmission. PennFuture also created a web page for the institute (http://www.midatlanticwind.org) that contains an online database of fact sheets, research reports, sample advocacy letters, top anti-wind claims and information on how to

  5. 50 CFR 229.34 - Harbor Porpoise Take Reduction Plan Regulations-Mid-Atlantic.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Harbor Porpoise Take Reduction Plan Regulations-Mid-Atlantic. 229.34 Section 229.34 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS AUTHORIZATION FOR COMMERCIAL FISHERIES UNDER THE MARINE...

  6. MID-ATLANTIC REGIONAL ASSESSMENT: OVERVIEW REPORT

    EPA Science Inventory

    This peer-reviewed report summarizes the findings of the first Mid-Atlantic Regional Assessment. The Mid-Atlantic Regional Assessment was led by a team from The Pennsylvania State University. The assessment was sponsored by and conducted in partnership with the U.S. Environmental...

  7. 76 FR 60605 - Magnuson-Stevens Fishery Conservation and Management Act Provisions; Fisheries of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-29

    ...NMFS hereby implements an omnibus amendment to all Mid- Atlantic Fishery Management Council (Council) fishery management plans (FMPs) to bring all Council FMPs into compliance with the annual catch limit (ACL) and accountability measure (AM) requirements of the Magnuson-Stevens Act (MSA). This rule is necessary to establish measures that address the MSA-required elements to utilize scientific......

  8. MID-ATLANTIC LANDCOVER CHANGE DATA BROWSER

    EPA Science Inventory

    The Mid-Atlantic region is comprised of southern New York, southern and western New Jersey, Pennsylvania, West Virginia, Maryland, Virginia, northeastern North Carolina, Delaware, and Washington, DC. It is an ecosystem rich in streams, wetlands, forests, estuaries, breeding birds...

  9. Forecasting fish biomasses, densities, productions, and bioaccumulation potentials of Mid-Atlantic wadeable streams

    EPA Science Inventory

    Regional fishery conditions of Mid-Atlantic wadeable streams in the eastern United States are estimated using the BASS bioaccumulation and fish community model and data collected by the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program (EMAP)....

  10. MID-ATLANTIC REGIONAL ASSESSMENT: PROJECT DESCRIPTION

    EPA Science Inventory

    As part of the USGCRP's First National Assessment effort, EPA's Global Change Research Program sponsored the first Mid-Atlantic Regional Assessment. A multi-disciplinary team of 14 Pennsylvania State University (Penn State) faculty members led this regional assessment effort.

  11. INNOVATIVE ENVIRONMENTAL EDUCATION CONTRIBUTES TO IMPROVED MANAGEMENT PRACTICES IN THE MID-ATLANTIC

    EPA Science Inventory

    The Mid-Atlantic Integrated Assessment (MAIA) and its partner, University of Maryland, Baltimore County (UMBC) have developed a graduate-level course focused on successful application of science by decision-makers to address a particular problem. Students conduct a literature rev...

  12. Nematocarcinus Milne Edwards, 1881 (Crustacea, Decapoda) from Southwestern Atlantic, including the Southern Mid-Atlantic Ridge area.

    PubMed

    Cardoso, Irene A; Burukovsky, Rudolf N

    2014-01-01

    The deep sea shrimp genus Nematocarcinus Milne Edwards, 1881 includes 47 species, ten of them have been recorded from the Atlantic Ocean. Herein, material sampled during three scientific projects (REVIZEE Central Fishery project; Campos Basin Deep Sea Environmental Project; Evaluation of Environmental Heterogeneity in the Campos Basin) made in the Southwestern Atlantic, off Brazil, is examined. In addition, material sampled from the South Mid Atlantic Ridge (MAR-ECO Project) was also examined. Four species are recorded for the first time to the southwestern Atlantic Ocean including Mid Atlantic Ridge area: Nematocarcinus faxoni Burukovsky, 2001; N. gracilipes Filhol, 1884; N. rotundus Crosnier & Forest, 1973 and N. tenuipes Spence-Bate, 1888. PMID:25543942

  13. Mid-Atlantic Wind - Overcoming the Challenges

    SciTech Connect

    Daniel F. Ancona III; Kathryn E. George; Lynn Sparling; Bruce C. Buckheit; Daniel LoBue; and Richard P. Bowers

    2012-06-29

    This study, supported by the US Department of Energy, Wind Powering America Program, Maryland Department of Natural Resources and Chesapeake Bay Foundation, analyzed barriers to wind energy development in the Mid-Atlantic region along with options for overcoming or mitigating them. The Mid-Atlantic States including Delaware, Maryland, North Carolina and Virginia, have excellent wind energy potential and growing demand for electricity, but only two utility-scale projects have been installed to date. Reasons for this apathetic development of wind resources were analyzed and quantified for four markets. Specific applications are: 1) Appalachian mountain ridgeline sites, 2) on coastal plains and peninsulas, 3) at shallow water sites in Delaware and Chesapeake Bays, Albemarle and Pamlico Sounds, and 4) at deeper water sites off the Atlantic coast. Each market has distinctly different opportunities and barriers. The primary barriers to wind development described in this report can be grouped into four categories; state policy and regulatory issues, wind resource technical uncertainty, economic viability, and public interest in environmental issues. The properties of these typologies are not mutually independent and do interact. The report concluded that there are no insurmountable barriers to land-based wind energy projects and they could be economically viable today. Likewise potential sites in sheltered shallow waters in regional bay and sounds have been largely overlooked but could be viable currently. Offshore ocean-based applications face higher costs and technical and wind resource uncertainties. The ongoing research and development program, revision of state incentive policies, additional wind measurement efforts, transmission system expansion, environmental baseline studies and outreach to private developers and stakeholders are needed to reduce barriers to wind energy development.

  14. Mid-Atlantic Wind - Overcoming the Challenges

    SciTech Connect

    Daniel F. Ancona III; Kathryn E. George; Richard P. Bowers; Dr. Lynn Sparling; Bruce Buckheit; Daniel LoBue

    2012-05-31

    This study, supported by the US Department of Energy, Wind Powering America Program, Maryland Department of Natural Resources and Chesapeake Bay Foundation, analyzed barriers to wind energy development in the Mid-Atlantic region along with options for overcoming or mitigating them. The Mid-Atlantic States including Delaware, Maryland, North Carolina and Virginia, have excellent wind energy potential and growing demand for electricity, but only two utility-scale projects have been installed to date. Reasons for this apathetic development of wind resources were analyzed and quantified for four markets. Specific applications are: 1) Appalachian mountain ridgeline sites, 2) on coastal plains and peninsulas, 3) at shallow water sites in Delaware and Chesapeake Bays, Albemarle and Pamlico Sounds, and 4) at deeper water sites off the Atlantic coast. Each market has distinctly different opportunities and barriers. The primary barriers to wind development described in this report can be grouped into four categories; state policy and regulatory issues, wind resource technical uncertainty, economic viability, and public interest in environmental issues. The properties of these typologies are not mutually independent and do interact. The report concluded that there are no insurmountable barriers to land-based wind energy projects and they could be economically viable today. Likewise potential sites in sheltered shallow waters in regional bay and sounds have been largely overlooked but could be viable currently. Offshore ocean-based applications face higher costs and technical and wind resource uncertainties. The ongoing research and development program, revision of state incentive policies, additional wind measurement efforts, transmission system expansion, environmental baseline studies and outreach to private developers and stakeholders are needed to reduce barriers to wind energy development.

  15. ECOLOGICAL CONDITION OF THE U.S. MID-ATLANTIC ESTUARIES: THE MID-ATLANTIC INTEGRATED ASSESSMENT (MAIA)

    EPA Science Inventory

    The Mid-Atlantic Integrated Assessment (MAIA-Estuaries) evaluated ecological conditions in US Mid-Atlantic estuaries during the summers of 1997 and 1998. Over 800 probability-based stations were monitored in four main estuarine systems?Chesapeake Bay, the Delaware Estuary, Maryla...

  16. Pathways of fish invasions in the Mid-Atlantic region of the United States

    USGS Publications Warehouse

    Lapointe, Nicolas W. R.; Fuller, Pam; Neilson, Matthew; Murphy, Brian R.; Angermeier, Paul

    2016-01-01

    Non-native fish introductions are a major threat to biodiversity and fisheries, and occur through numerous pathways that vary regionally in importance. A key strategy for managing invasions is to focus prevention efforts on pathways posing the greatest risk of future introductions. We identified high-risk pathways for fish establishment in the Mid-Atlantic region of the United States based on estimates of probability of establishment and records of previous introductions, which were considered in the context of emerging socioeconomic trends. We used estimates of propagule pressure, species’ environmental tolerance, and size of species pool to assess the risk of establishment by pathway. Pathways varied considerably in historic importance and species composition, with the majority of species introduced intentionally via stocking (primarily for sport, forage, or biocontrol) or bait release. Bait release, private stocking, illegal introductions intended to establish reproducing populations (e.g., of sport fish), aquaculture, and the sale of live organisms all create risks for future invasions in the Mid-Atlantic region. Of these pathways, bait release probably poses the greatest risk of introductions for the Mid-Atlantic region because propagule pressure is moderate, most released species are tolerant of local environmental conditions, and the pool of species available for transplantation is large. Our findings differ considerably from studies in other regions (e.g., bait release is a dominant pathway in the Mid-Atlantic region, whereas illegal introduction of sport fish is dominant in the western US and aquarium releases are dominant in Florida), demonstrating the need for regional-scale assessments of, and management strategies for, introduction pathways.

  17. Satellite Movie Sees Major Winter Storm Nearing Mid-Atlantic

    NASA Video Gallery

    This animation NOAA's GOES-East satellite imagery from Jan. 20 to 22 shows the movement of the system that is expected to bring a powerful winter storm to the U.S. Mid-Atlantic region. Credit: NASA...

  18. MAIA PROJECT SUMMARY: CONDITION OF THE MID-ATLANTIC ESTUARIES

    EPA Science Inventory

    The Mid-Atlantic Integrated Assessment (MAIA) is an interagency, multi disciplinary research, monitoring and assessment program to develop high-quality scientific information on the region's natural resources: current condition, stresssors, trends, and vulnerabilities. MAIA resul...

  19. Forecasting fish biomasses, densities, productions, and bioaccumulation potentials of mid-atlantic wadeable streams.

    PubMed

    Barber, M Craig; Rashleigh, Brenda; Cyterski, Michael J

    2016-01-01

    Regional fishery conditions of Mid-Atlantic wadeable streams in the eastern United States are estimated using the Bioaccumulation and Aquatic System Simulator (BASS) bioaccumulation and fish community model and data collected by the US Environmental Protection Agency's Environmental Monitoring and Assessment Program (EMAP). Average annual biomasses and population densities and annual productions are estimated for 352 randomly selected streams. Realized bioaccumulation factors (BAF) and biomagnification factors (BMF), which are dependent on these forecasted biomasses, population densities, and productions, are also estimated by assuming constant water exposures to methylmercury and tetra-, penta-, hexa-, and hepta-chlorinated biphenyls. Using observed biomasses, observed densities, and estimated annual productions of total fish from 3 regions assumed to support healthy fisheries as benchmarks (eastern Tennessee and Catskill Mountain trout streams and Ozark Mountains smallmouth bass streams), 58% of the region's wadeable streams are estimated to be in marginal or poor condition (i.e., not healthy). Using simulated BAFs and EMAP Hg fish concentrations, we also estimate that approximately 24% of the game fish and subsistence fishing species that are found in streams having detectable Hg concentrations would exceed an acceptable human consumption criterion of 0.185 μg/g wet wt. Importantly, such streams have been estimated to represent 78.2% to 84.4% of the Mid-Atlantic's wadeable stream lengths. Our results demonstrate how a dynamic simulation model can support regional assessment and trends analysis for fisheries. PMID:25858149

  20. 76 FR 19329 - New England Fishery Management Council (NEFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-07

    ... limit exemptions in the monkfish cooperative research program. The Northeast Fisheries Science Center... Fisheries Regional Administrator (Northeast Region), Northeast Fisheries Science Center and Mid-Atlantic... relationships among the NEFMC, the Northeast Regional Office, and the Northeast Fisheries Science Center...

  1. Educator Effectiveness Series: Assessing School Climate. Q&A with Jonathan Cohen, Ph.D. REL Mid-Atlantic Webinar

    ERIC Educational Resources Information Center

    Cohen, Jonathan

    2015-01-01

    The REL Mid-Atlantic Webinar discussed the elements in a positive school climate and shared different methods for assessing school data, including the Comprehensive School Climate Inventory. The Q&A presented in this document address the questions participants had for Dr. Cohen following the webinar. The webinar recording and PowerPoint…

  2. 77 FR 32082 - New England Fishery Management Council (NEFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-31

    ... Science Center (NEFSC) will present a briefing on their new social science data collection efforts... Regional Administrator (Northeast Region), the Northeast Fisheries Science Center and Mid-Atlantic...

  3. Microbial gene analysis of Mid-Atlantic CEAP wetlands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Mid-Atlantic Regional Conservation Effects Assessment Project (CEAP)-Wetland Study is one of five regional studies underway as part of the national CEAP-Wetland effort. This study collected information at sites in the DelMarVa and North Carolina coastal plain regions, and sites were equally divi...

  4. BIOLOGICAL INTEGRITY IN MID-ATLANTIC COASTAL PLAINS HEADWATER STREAMS

    EPA Science Inventory

    The objective of this study was to assess the applicability of using landscape variables in conjunction with water quality and benthic data to efficiently estimate stream condition of select headwater streams in the Mid-Atlantic Coastal Plains. Eighty-two streams with riffle sit...

  5. Characterization of Intraplate Seismicity in the Mid-Atlantic US

    NASA Astrophysics Data System (ADS)

    Soto-Cordero, L.; Meltzer, A.; Stachnik, J. C.

    2015-12-01

    Using data from the USArray TA and permanent seismic stations we explore the relationship between seismicity and lithospheric structure in the Mid-Atlantic US where previous studies suggest the clustering of seismicity within several seismic zones. Given low strain rates, creating a robust catalog of tectonic events with a low magnitude threshold is essential. Analysis of events in our study region with hypocenters determined by the Array Network Facility (ANF) during the last 2 years shows that 51% have a depth equal to zero. To assess whether the events are of natural or anthropogenic origin we apply a series of discriminants, such as, geographic correlation to known mining sites, temporal clustering and waveform characteristics. Using West Virginia as a test, we found 100% of events with zero depth are associated with mining operations. Interesting patterns emerge when comparing ANF locations of depths greater than zero with historic seismicity and events instrumentally recorded by permanent stations. Seismicity occurs in some regions where no seismic activity had been previously observed but events along the boundary between the Piedmont and Coastal Plain appear as a continuous band of seismicity making it more difficult to identify discrete seismic zones. Earthquake magnitude threshold is also examined in preparation for high-precision relocation of the events to better address the spatio-temporal nature of seismicity in the region. The ANF catalog shows a magnitude of completeness to 2.2 in the region. However, the ANSS catalog shows 58 events M≤2.2 in the last 2 years while the ANF catalog provides location for only 12 of those events (21%). Continued efforts to calibrate the detection and association algorithms will help lower the magnitude threshold and complete the catalog.

  6. GLOBAL CHANGE RESEARCH NEWS #17: PUBLICATION OF MID-ATLANTIC REGIONAL ASSESSMENT

    EPA Science Inventory

    The report, "Preparing for a Changing Climate: The Potential Consequences of Climate Variability and Change - Mid-Atlantic Overview", summarizes the findings of the first Mid-Atlantic Regional Assessment. The Mid-Atlantic Regional Assessment was led by a team from The Pennsylvani...

  7. Composition of basalts from the Mid-Atlantic Ridge

    USGS Publications Warehouse

    Engel, A.E.J.; Engel, C.G.

    1964-01-01

    Studies of volcanic rocks in dredge hauls from the submerged parts of the Mid-Atlantic Ridge suggest that it consists largely of tholeiitic basalt with low values of K, Ti, and P. In contrast, the volcanic islands which form the elevated caps on the Ridge are built of alkali basalt with high values of Ti, Fe3+, P, Na, and K. This distinct correlation between the form of the volcanic structures, elevation above the sea floor, and composition suggests that the islands of alkali basalt are derived from a parent tholeiitic magma by differentiation in shallow reservoirs. The volume of low-potassium tholeiites along the Mid-Atlantic Ridge and elsewhere in the oceans appears to be many times that of the alkali basalts exposed on oceanic islands. Tholeiitic basalts with about 0.2 K2O appear to be the primary and predominant magma erupted on the oceanic floor.

  8. An introduction to mid-Atlantic seasonal pools

    USGS Publications Warehouse

    Brown, L.J.; Jung, R.E.

    2005-01-01

    Seasonal pools, also known as vernal ponds, provide important ecological services to the mid-Atlantic region. This publication serves as an introduction to seasonal pool ecology and management; it also provides tools for exploring seasonal pools, including a full-color field guide to wildlife. Seasonal pools are defined as having four distinctive features: surface water isolation, periodic drying, small size and shallow depth, and support of a characteristic biological community. Seasonal pools experience regular drying that excludes populations of predatory fish. Thus, pools in the mid-Atlantic region provide critical breeding habitat for amphibian and invertebrate species (e.g., spotted salamander (Ambystoma maculatum), wood frog (Rana sylvatica), and fairy shrimp (Order Anostraca)) that would be at increased risk of predation in more permanent waters. The distinctive features of seasonal pools also make them vulnerable to human disturbance. In the mid-Atlantic region, land-use changes pose the greatest challenges to seasonal pool conservation. Seasonal pools are threatened by direct loss (e.g., filling or draining of the pool) as well as by destruction and fragmentation of adjoining terrestrial habitat. Many of the species that depend on seasonal pools for breeding spend the majority of their lives in the surrounding lands that extend a radius of 1000 feet or more from the pools; these vital habitats are being transected by roads and converted to other land uses. Other threats to seasonal pools include biological introductions and removals, mosquito control practices, amphibian diseases, atmospheric deposition, and climate change. The authors recommend a three-pronged strategy for seasonal pool conservation and management in the mid-Atlantic region: education and research, inventory and monitoring of seasonal pools, and landscape-level planning and management.

  9. Ecosystem services and cooperative fisheries research to address a complex fishery problem

    EPA Science Inventory

    The St. Louis River represents a complex fishery management problem. Current fishery management goals have to be developed taking into account bi-state commercial, subsistence and recreational fisheries which are valued for different characteristics by a wide range of anglers, as...

  10. Diet of mid-Atlantic Sowerby's beaked whales Mesoplondon bidens

    NASA Astrophysics Data System (ADS)

    Pereira, J. N.; Neves, V. C.; Prieto, R.; Silva, M. A.; Cascão, I.; Oliveira, C.; Cruz, M. J.; Medeiros, J. V.; Barreiros, J. P.; Porteiro, F. M.; Clarke, D.

    2011-11-01

    The first mid-Atlantic diet of Mesoplodon beaked whales is presented, from ten Sowerby's Mesoplodon bidens stranded in the Azores region between 2002 and 2009. This doubles the worldwide number of stomachs sampled, and reveals new feeding habits for this species. The mean number of prey items per stomach was 85±89 (range: 12-238), with fish accounting for 99.3% and cephalopods contributing less than 1% of total prey. Fish otoliths from 15 families and cephalopod lower mandibles from three families were identified, representing 22 taxa. The diet consisted mainly of small mid-water fish, the most numerous being Diaphus sp., Lampanyctus sp. and Melamphaidae species. Myctophids were present in all stranded individuals, followed by Diretmidae, Melamphaidae and Opisthoproctus soleatus, while the remaining fish species were scarce or single occurrences. Consistency of diet in four different years reveals a divergence from all previous records in continental areas, where mainly neritic and shelf-break benthopelagic fish species have been reported. Mid-Atlantic Sowerby's beaked whales' showed dietary plasticity, feeding on the most abundant mid-water groups occurring between 0 and750 m. Trophic level from prey numerical frequency was estimated at 4.4±0.46.

  11. Comparative visual ecophysiology of mid-Atlantic temperate reef fishes

    PubMed Central

    Horodysky, Andrij Z.; Brill, Richard W.; Crawford, Kendyl C.; Seagroves, Elizabeth S.; Johnson, Andrea K.

    2013-01-01

    Summary The absolute light sensitivities, temporal properties, and spectral sensitivities of the visual systems of three mid-Atlantic temperate reef fishes (Atlantic spadefish [Ephippidae: Chaetodipterus faber], tautog [Labridae: Tautoga onitis], and black sea bass [Serranidae: Centropristis striata]) were studied via electroretinography (ERG). Pelagic Atlantic spadefish exhibited higher temporal resolution but a narrower dynamic range than the two more demersal foragers. The higher luminous sensitivities of tautog and black sea bass were similar to other benthic and demersal coastal mid-Atlantic fishes. Flicker fusion frequency experiments revealed significant interspecific differences at maximum intensities that correlated with lifestyle and habitat. Spectral responses of the three species spanned 400–610 nm, with high likelihood of cone dichromacy providing the basis for color and contrast discrimination. Significant day-night differences in spectral responses were evident in spadefish and black sea bass but not tautog, a labrid with characteristic structure-associated nocturnal torpor. Atlantic spadefish responded to a wider range of wavelengths than did deeper-dwelling tautog or black sea bass. Collectively, these results suggest that temperate reef-associated fishes are well-adapted to their gradient of brighter to dimmer photoclimates, representative of their unique ecologies and life histories. Continuing anthropogenic degradation of water quality in coastal environments, at a pace faster than the evolution of visual systems, may however impede visual foraging and reproductive signaling in temperate reef fishes. PMID:24285711

  12. THE MID-ATLANTIC INTEGRATED ASSESSMENT MAIA - ESTUARIES 1997-1998 SUMMARY REPORT

    EPA Science Inventory

    During the summers of 1997-98, a consortium of federal and state environmental agencies conducted the Mid-Atlantic Integrated Assessment (MAIA) program to characterize the environmental condition of the four major estuaries in the the mid-Atlantic region of the United States. The...

  13. COLLABORATIVE RESEARCH, MONITORING AND ASSESSMENT IN THE MID-ATLANTIC REGION

    EPA Science Inventory

    EPA Region 3 to implement a long-term research, monitoring, and assessment program in the Mid-Atlantic region - the Mid-Atlantic Integrated Assessment (MAIA). The MAIA mission is to develop a broad-based partnership to integrate scientific knowledge into the decision-making proc...

  14. Mid-Atlantic Consumer Purchasing Behavior and Knowledge of Locally Grown and Seasonal Produce

    ERIC Educational Resources Information Center

    Chamberlain, Amy J.; Kelley, Kathleen M.; Hyde, Jeffrey

    2013-01-01

    Mid-Atlantic urban consumers were surveyed on their fruit and vegetable purchasing behaviors and their knowledge of produce grown in the region. Consumers were generally unaware of what produce is grown in the mid-Atlantic and during what months they are harvested. Additionally, differences pertaining to number of produce items purchased were…

  15. GLOBAL CHANGE RESEARCH NEWS #6: PUBLICATION OF FIRST REPORT FROM MID-ATLANTIC REGIONAL ASSESSMENT (MARA)

    EPA Science Inventory

    This research news edition announces the publication of the first report from the Mid-Atlantic Regional Assessment (MARA). The report is entitled, *Climate Change Impacts in the Mid-Atlantic Region -- A Workshop Report.* MARA is being conducted as part of the USGCRP First Nation...

  16. Pesticides in surface water of the Mid-Atlantic region

    USGS Publications Warehouse

    Ferrari, Matthew J.; Ator, Scott W.; Blomquist, Joel D.; Dysart, Joel E.

    1997-01-01

    Water-quality data from 463 surface-water sites were compiled and analyzed to document the occurrence and distribution of pesticides in surface water of the Mid-Atlantic region as part of the Mid-Atlantic Integrated Assessment program of the U.S. Environmental Protection Agency. Those data collected by the U.S. Geological Survey from October 1973 through March 1997 were used in the analyses. Data are available for a large part of the Mid-Atlantic region, but large spatial gaps in the data do exist. USGS data bases contained analyses of surface-water samples for 127 pesticide compounds, including 12 degradates, but only 16 of the compounds were commonly detected. Atrazine, metolachlor, simazine, prometon, alachlor, tebuthiuron, cyanazine, diazinon, carbaryl, chlorpyrifos, pendimethalin, 2,4-D, dieldrin, DCPA, metribuzin, and desethylatrazine (an atrazine degradate) were detected in more than 100 of the samples analyzed. At least one pesticide was detected in about 75 percent of the samples collected and at more than 90 percent of the sites sampled. Concentrations greater than the Federal Maximum Contaminant Level (MCL) for drinking water of 3 micrograms per liter (ug/L) for atrazine were found in 67 of 2,076 samples analyzed; concentrations greater than the MCL of 2ug/L for alachlor were found in 13 of 1,693 samples analyzed, and concentrations greater than the MCL of 4 ug/L for simazine were found in 17 of 1,995 samples analyzed. Concentrations of four pesticides were greater than Federal Health Advisory levels for drinking water, and concentrations of nine pesticides were greater than Federal Ambient Water-Quality Criteria for the Protection of Aquatic Organisms. Streams draining basins with different land uses tend to have different pesticide detection frequencies and median concentrations. Median concentrations of herbicides tend to be highest in streams draining basins in which the major land use is agriculture, whereas median concentrations of insecticides

  17. Dynamics of the direct intrusion of Gulf Stream ring water onto the Mid-Atlantic Bight shelf

    NASA Astrophysics Data System (ADS)

    Zhang, Weifeng G.; Gawarkiewicz, Glen G.

    2015-09-01

    Onshore intrusions of offshore waters onto the Mid-Atlantic Bight shelf can greatly affect shelf circulation, biogeochemistry, and fisheries. Previous studies have concentrated on onshore intrusions of slope water. Here we present a direct intrusion of Gulf Stream warm-core ring water onto the shelf representing a previously unknown exchange process at the shelfbreak. Impingement of warm-core rings at the shelfbreak generates along-isobath intrusions that grow like Pinocchio's nose, extending hundreds of kilometers to the southwest. By combining satellite and Ocean Observatory Initiative Pioneer Array data and idealized numerical simulations, we discover that the intrusion results from topographically induced vorticity variation of the ring water, rather than from entrainment of the shelfbreak frontal jet. This intrusion of the Gulf Stream ring water has important biogeochemical implications and could facilitate migration of marine species across the shelfbreak barrier and transport low-nutrient surface Gulf Stream ring water to the otherwise productive shelfbreak region.

  18. 78 FR 3401 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-16

    ... the human environment of alternative measures to protect deep-sea corals in the Mid-Atlantic region... identifying the significant issues related to deep-sea coral protections in the Mid-Atlantic. This notice is..., and Butterfish (MSB), which addresses protections of deep-sea corals from the impacts of fishing...

  19. A STRATEGY FOR INTEGRATED ECOLOGICAL RESTORATION OF RIPARIAN BUFFERS IN THE MID-ATLANTIC REGION

    EPA Science Inventory

    Increased sediments, nutrients, and other contaminants in the Mid-Atlantic region contribute to environmental problems ranging from stream degradation to possibly Pfiesteria attacks in Chesapeake Bay. Restoring riparian areas - the filters between terrestrial watersheds and aquat...

  20. RAILROAD DIGITAL LINE GRAPHS FOR THE MID-ATLANTIC INTEGRATED ASSESSMENT (MAIA) STUDY AREA

    EPA Science Inventory

    This data set is a geographic information system (GIS) coverage of railroads for the United States Environmental Protection Agency (USEPA) Mid-Atlantic Integrated Assessment (MAIA) Project region. The coverage was produced using US Geological Survey transportation digital line ...

  1. Mid-Atlantic Technology Applications Center. Quarters 1-4

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Mid-atlantic Technology Application Center (MTAC) pursued a number of initiatives designed to enhance the strategic position of the Langley Research Center (LaRC) and NASA in industry. Among these was a closer association with the ISA, International Society for Measurement and Control. During 1997, MTAC placed articles regarding NASA-developed technologies in each In Tech magazine. The monthly magazine is sent to 46,000 sensors and instrumentation professionals. In addition, MTAC coordinated NASXs participation in the ISA Tech 97 Conference, securing $112,000 of free exhibit space, 1500 NASA sensors posters at no cost to NASA, and thousands of dollars of free publicity. MTAC was awarded a contract by ISA to operate its Technical Resource Center (TRC). The goal of this project is to determine what user needs are in order to identify opportunities for collaboration between NASA centers and companies. In addition, the TRC work will lay the groundwork for the Technology Development Consortium (TDC) proposed by MTAC. The purpose of the TDC is to: match current industry needs with NASA technologies available now, and to identify future needs of NASA and industry which may lead to dual use projects. The goal of these activities is twofold: to infuse NASA technologies into the sensors and instrumentation industry and to secure industry funds to support NASA technology development projects. The instrumentation and sensors industry is valued at $30 billion worldwide, with $12 billion in sales in the United States. The growth rate averages 13.5%, so that by the year 2000, the industry will produce products worth $49 billion. More than 80% of instruments, sensors and control systems are currently manufactured in the United States. NASA and the industry do not have a history of collaborative projects; MTAC's initiatives in this area are designed to foster working relationships between the two parties that will help maintain U.S. leadership in this field. Mid-atlantic Technology

  2. Phytoplankton Assemblage Patterns in the Southern Mid-Atlantic Bight

    NASA Technical Reports Server (NTRS)

    Makinen, Carla; Moisan, Tiffany A. (Editor)

    2012-01-01

    As part of the Wallops Coastal Oceans Observing Laboratory (Wa-COOL) Project, we sampled a time-series transect in the southern Mid-Atlantic Bight (MAB) biweekly. Our 2-year time-series data included physical parameters, nutrient concentrations, and chlorophyll a concentrations. A detailed phytoplankton assemblage structure was examined in the second year. During the 2-year study, chlorophyll a concentration (and ocean color satellite imagery) indicated that phytoplankton blooms occurred in January/February during mixing conditions and in early autumn under stratified conditions. The chlorophyll a concentrations ranged from 0.25 microgram 1(exp -1) to 15.49 microgram 1(exp -1) during the 2-year period. We were able to discriminate approximately 116 different species under phase contrast microscopy. Dominant phytoplankton included Skeletonema costatum, Rhizosolenia spp., and Pseudo-nitzschia pungens. In an attempt to determine phytoplankton species competition/succession within the assemblage, we calculated a Shannon Weaver diversity index for our diatom microscopy data. Diatom diversity was greatest during the winter and minimal during the spring. Diatom diversity was also greater at nearshore stations than at offshore stations. Individual genera appeared patchy, with surface and subsurface patches appearing abruptly and persisting for only 1-2 months at a time. The distribution of individual species differed significantly from bulk variables of the assemblage (chlorophyll a ) and total phytoplankton assemblage (cells), which indicates that phytoplankton species may be limited in growth in ways that differ from those of the total assemblage. Our study demonstrated a highly diverse phytoplankton assemblage throughout the year, with opportunistic species dominating during spring and fall in response to seasonal changes in temperature and nutrients in the southern MAB.

  3. Variability of particulate flux over the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Abell, Richard E.; Brand, Tim; Dale, Andrew C.; Tilstone, Gavin H.; Beveridge, Christine

    2013-12-01

    The magnitude and composition of the sinking-particle flux were studied over the northern Mid-Atlantic Ridge (MAR) from June 2007 to July 2010. Four moorings equipped with dual sediment traps, 100 m and 1000 m above the sea floor, sampled regions north and south of the Charlie Gibbs Fracture Zone (between 49°N and 54°N) and east and west of the MAR. Biogenic data were coupled with satellite estimates of primary production and modelled particle source to assess the variability in export flux. Large variations were found in the seasonality, chemical composition, magnitude and source of sinking particulate material between mooring sites. The northern moorings recorded both greater mean primary production and greater particle mass flux than the southern moorings, although, the large inter-annual variability within the sites exceeded inter-site differences. While estimates of primary production and organic carbon fluxes are comparable to other investigations of this type, they are notably lower than previous estimates for the abyssal plain of the North Atlantic. The deeper traps consistently recorded a higher mass flux compared to the shallower traps. However, we suggest that the overall flux recorded by the shallower traps was reduced by trapping inefficiency, which in the light of the low current velocities, may largely be due to the physical nature of the sinking material. Although deep-trap flux estimates may be more susceptible to errors due to re-suspended and advected material from nearby topography, mass flux and current velocity are not linked. In addition, the relatively low aluminium concentration of the deep-trap material indicates that this contribution is relatively small. The organic carbon flux to the NE, NW, SE and SW station was 0.8, 1.2, 1.1 and 1.1 g m-2 y-1 respectively, corresponding to an export flux of 0.6% over this region of the MAR.

  4. The deep biosphere below North Pond: A mid-Atlantic microbial observatory

    NASA Astrophysics Data System (ADS)

    Edwards, K. J.; Bach, W.; Klaus, A.

    2011-12-01

    IODP Expedition 336 (Sept-Nov 2011) was executed to address fundamental microbiological questions concerning the nature of the subseafloor deep biosphere in oceanic hydrological, geological, and biogeochemical context (Edwards et al., 2010). Our principal objective is to study the subseafloor microbiological communities in young igneous ocean crust, in order to understand their role in ocean crust alteration and their ecology in hydrological and biogeochemical context. Specifically, we are testing the hypothesis that microbes play an active role in ocean crust alteration, while also exploring broad based ecological questions such as how hydrological structure and geochemistry influence microbial community structures. We will accomplish this by installing borehole observatories (CORKs) for coupled microbiological, geochemical, and hydrological experiments. These CORKs will allow us to monitor conditions and study processes in-situ,after the drilling disturbance and contaminating influences in the borehole environment have dissipated. Operations during Expedition 336 will lay the foundation for long-term monitoring, experimentation, and observations by subsequent ROV or submersible dive expeditions. CORKs will be used in perturbation and monitoring points for single- and cross-hole experiments, and will use recently developed novel in-situ microbiological experimentation system "FLOCS" (Orcutt et al., 2010a; Orcutt et al., 2010b). This talk will present initial results from Expedition 336 and discuss plans for future observatory operations. Edwards KJ, Bach W, Klaus A (2010). Mid-Atlantic ridge flank microbiology: Initiation of long-term coupled microbiological, geochemical, and hydrological experimentation within the seafloor at North Pond, western flank of the Mid-Atlantic ridge. IODP Sci. Prosp., 336. Integrated Ocean Drilling Program: College Station, TX. p 62 pp.http://publications.iodp.org/scientific_prospectus/336/ Orcutt B, Wheat CG, Edwards KJ (2010a

  5. An index of biological integrity for northern Mid-Atlantic Slope drainages

    USGS Publications Warehouse

    Daniels, R.A.; Riva-Murray, K.; Halliwell, D.B.; Vana-Miller, D. L.; Bilger, M.D.

    2002-01-01

    An index of biological integrity (IBI) was developed for streams in the Hudson, Delaware, and Susquehanna River drainages in the northeastern United States based on fish assemblage data from the Mohawk River drainage of New York. The original IBI, developed for streams in the U.S. Midwest, was modified to reflect the assemblage composition and structure present in Mid-Atlantic Slope drainages. We replaced several of the Midwestern IBI metrics and criteria scores because fishes common to the Midwest are absent from or poorly represented in the Northeast and because stream fish assemblages in the Northeast are less rich than those in the Midwest. For all replacement metrics we followed the ecology-based rationale used in the development of each of the metrics of the Midwestern IBI so that the basic theoretical underpinnings of the IBI remained unchanged. The validity of this modified IBI is demonstrated by examining the quality of streams in the Hudson, Delaware, and lower Susquehanna River basins. The relationships between the IBI and other indicators of environmental quality are examined using data on assemblages of fish and benthic macroinvertebrates and on chemical and physical stream characteristics obtained during 1993-2000 by the U.S. Geological Survey's National Water Quality Assessment Program in these three river basins. A principal components analysis (PCA) of chemical and physical variables from 27 sites resulted in an environmental quality gradient as the primary PCA axis (eigenvalue, 0.41 ). Principal components analysis site scores were significantly correlated with such benthic macroinvertebrate metrics as the percentage of Ephemeroptera, Plecoptera, and Trichoptera taxa (Spearman R = -0.66, P < 0.001). Index of biological integrity scores for sites in these three river basins were significantly correlated with this environmental quality gradient (Spearman R = -0.78, P = 0.0001). The northern Mid-Atlantic Slope IBI appears to be sensitive to

  6. Shelf-Slope Exchange in the Mid-Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Goodman, P. J.; Wilkin, J.

    2004-12-01

    A high resolution model (ROMS, the Regional Ocean Modeling System) of U.S. East Coast circulation from Newfoundland to Cuba is used to explore features of alongshelf freshwater transport, residence time, and shelf-sea/deep-ocean exchange. The focus of the analysis is the Mid-Atlantic Bight (MAB) shelf-slope system which, like continental shelves throughout the world, contributes to the oceanic budgets of heat, salt, and fresh water. In addition, the "continental shelf pump" transfers carbon from the atmosphere to the deep ocean through fluxes of dissolved organic carbon and particulate organic carbon off the shelves. Solar radiation, evaporation, rainfall, riverine input, gas exchange with the atmosphere, and biological production all modify the character of shelf waters. In the MAB, the shelf-slope front separates shallow coastal waters from slope waters and the Gulf Stream, extending residence times on the shelf and maintaining coastal salinities at significantly lower levels than those offshore. The southwestward coastal mean flow exchanges weakly with slope waters along most of the MAB, with the strongest offshore flow occurring at Cape Hatteras where much of the flow is entrained into the Gulf Stream front. The shelf circulation is influenced by input from the Hudson and Delaware Rivers and Chesapeake Bay. Along the shelf break, exchange is modulated by warm-core rings from the Gulf Stream and variability of the shelf-break front. Key features of the seasonal circulation such as the MAB "Cold Pool" are captured by the simulation. Measurements suggest that DOC in shelf and shallow slope waters of the MAB include both old marine carbon and a young terrestrial-riverine-estuarine component, and these carbon cycling processes are being studied with a companion primary production, nitogen and carbon cycle model directly coupled to ROMS. Results showing salinity, idealized dye and Lagrangian float tracking results from a ROMS simulation of the MAB shelf circulation

  7. Traumatic uveitis in the mid-Atlantic United States

    PubMed Central

    Engelhard, Stephanie B; Patrie, James; Prenshaw, John; Bajwa, Asima; Monahan, Rose; Reddy, Ashvini K

    2015-01-01

    Purpose The purpose of this study was to conduct an in-depth analysis of traumatic uveitis in patients managed in a mid-Atlantic tertiary care center with the goal of better characterizing the clinical features and outcomes of this large and important subset of uveitis patients. Methods This was a retrospective, observational study comparing traumatic uveitis patients with nontraumatic uveitis patients seen at the University of Virginia, Charlottesville, VA, USA, from 1984 to 2014. Results Fifty-four traumatic uveitis patients (55 eyes) were identified. The patient population was 70.4% male, 57.4% Caucasian, and 37.0% African American. Mean age at diagnosis was 31.2 years; mean duration of follow-up was 5.4 years; and mean number of visits to the clinic was 4. The most common treatment modality was local steroids (77.8%). Glaucoma was medically managed in eight patients (14.8%). Cataract surgery was performed in five patients (9.3%). Mean best-corrected visual acuity at baseline for traumatic uveitis patients was 0.33 logMAR (SD 0.42) at the initial visit and 0.16 logMAR (SD 0.33) at the final visit. Mean baseline intraocular pressure (IOP) in the traumatic uveitis group was 15.5 mmHg (SD 7.4) at the initial visit and 14.6 mmHg (SD 4.0) at the final visit. Patients in the traumatic uveitis cohort tended to have better visual outcomes than those in the nontraumatic uveitis cohort. Conclusion In our series, traumatic uveitis patients tended to be young and male and present with unilateral disease, all findings consistent with other reports. Despite relatively good visual outcomes, the traumatic uveitis patients still experienced a high burden of disease, measured both in the number of clinic visits and duration of follow-up. Due to the young mean age of patients, these disease burdens and decreased quality of life are nontrivial, emphasizing the importance of careful management and prompt treatment of this subset of uveitis patients. PMID:26491249

  8. 75 FR 70192 - Fisheries of the Northeastern United States; Summer Flounder, Scup, and Black Sea Bass Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-17

    ... Fishing Permits (EFPs) as part of the Mid-Atlantic Fishery Management Council's (Council) Research Set... Fishery Management Plan (FMP) require NMFS to publish specifications for the upcoming fishing year for... the Magnuson-Stevens Fishery Conservation and Management Act (Magnuson-Stevens Act), 16 U.S.C. 1801...

  9. Assisting Students Struggling with Mathematics: Response to Intervention (RtI) for Elementary and Middle Schools. Q&A with Ben Clarke Ph.D and Paul Riccomini, Ph.D. REL Mid-Atlantic Event

    ERIC Educational Resources Information Center

    Clarke, Ben; Riccomini, Paul

    2013-01-01

    This REL Mid-Atlantic Event focused on effective strategies for screening, instruction, and differentiation of instruction as part of math RtI implementation. The Q&A presented in this document address the questions participants had for Dr. Clarke and Dr. Riccomini following the event. Dr. Clarke's and Dr. Riccomini's PowerPoint presentations…

  10. Relative species richness and community completeness: avian communities and urbanization in the mid-Atlantic states

    USGS Publications Warehouse

    Cam, E.; Nichols, J.D.; Sauer, J.R.; Hines, J.E.; Flather, C.H.

    2000-01-01

    The idea that local factors govern local richness has been dominant for years, but recent theoretical and empirical studies have stressed the influence of regional factors on local richness. Fewer species at a site could reflect not only the influence of local factors, but also a smaller regional pool. The possible dependency of local richness on the regional pool should be taken into account when addressing the influence of local factors on local richness. It is possible to account for this potential dependency by comparing relative species richness among sites, rather than species richness per se. We consider estimation of a metric permitting assessment of relative species richness in a typical situation in which not all species are detected during sampling sessions. In this situation, estimates of absolute or relative species richness need to account for variation in species detection probability if they are to be unbiased. We present a method to estimate relative species richness based on capture-recapture models. This approach involves definition of a species list from regional data, and estimation of the number of species in that list that are present at a site-year of interest. We use this approach to address the influence of urbanization on relative richness of avian communities in the Mid-Atlantic region of the United States. There is a negative relationship between relative richness and landscape variables describing the level of urban development. We believe that this metric should prove very useful for conservation and management purposes because it is based on an estimator of species richness that both accounts for potential variation in species detection probability and allows flexibility in the specification of a 'reference community.' This metric can be used to assess ecological integrity, the richness of the community of interest relative to that of the 'original' community, or to assess change since some previous time in a community.

  11. 75 FR 360 - Solios Power Trading LLC; Solios Power Mid-Atlantic Trading LLC; Solios Power Midwest Trading LLC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ... Energy Regulatory Commission Solios Power Trading LLC; Solios Power Mid-Atlantic Trading LLC; Solios Power Midwest Trading LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...-referenced proceeding of Solios Power Trading LLC, Solios Power Mid-Atlantic Trading LLC, and Solios...

  12. 78 FR 54644 - 2013 Fall Joint Meeting of the Ozone Transport Commission and the Mid-Atlantic Northeast...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-05

    ... AGENCY 2013 Fall Joint Meeting of the Ozone Transport Commission and the Mid-Atlantic Northeast... Transport Commission (OTC) and the Mid-Atlantic Northeast Visibility Union (MANE-VU). The meeting agenda...: For documents and press inquiries contact: Ozone Transport Commission, 444 North Capitol Street...

  13. 77 FR 5008 - Solios Power Mid-Atlantic Virtual LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-01

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Solios Power Mid-Atlantic Virtual LLC; Supplemental Notice That Initial... notice in the above-referenced proceeding of Solios Power Mid-Atlantic Virtual LLC's application...

  14. 75 FR 48666 - Calpine Mid-Atlantic Marketing, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-11

    ... Energy Regulatory Commission Calpine Mid-Atlantic Marketing, LLC; Supplemental Notice That Initial Market... supplemental notice in the above-referenced proceeding, of Calpine Mid-Atlantic Marketing, LLC's application for market-based rate authority, with an accompanying rate schedule, noting that such...

  15. Contribution of dissolved organic nitrogen deposition to mid-Atlantic coastal waters. Precipitation concentration, isotopic composition and wet flux

    SciTech Connect

    Galloway, J.N.; Macko, S.A.; Russell, K.M.; Scudlark, J.R.; Church, T.M.

    1998-03-01

    There is a substantial evidence that power-plant emissions of NOx are a significant source of nitrogen (N) in atmospheric wet deposition to the mid-Atlantic region. To be able to ascertain the contribution of power-plant emissions to total nitrogen wet deposition in the mid-Atlantic region, two pices of information are required.

  16. STATISTICAL TECHNIQUES FOR DETERMINATION AND PREDICTION OF FUNDAMENTAL FISH ASSEMBLAGES OF THE MID-ATLANTIC HIGHLANDS

    EPA Science Inventory

    A statistical software tool, Stream Fish Community Predictor (SFCP), based on EMAP stream sampling in the mid-Atlantic Highlands, was developed to predict stream fish communities using stream and watershed characteristics. Step one in the tool development was a cluster analysis t...

  17. PREDICTION OF FUNDAMENTAL ASSEMBLAGES OF MID-ATLANTIC HIGHLAND STREAM FISHES

    EPA Science Inventory

    A statistical software tool, the Stream Fish Assemblage Predictor (SFAP), based on stream sampling data collected by the EPA in the mid-Atlantic Highlands, was developed to predict potential stream fish communities using characteristics of the stream and its watershed.
    Step o...

  18. Characterization Methods for Small Estuarine Systems in the Mid-Atlantic Region of the United States

    EPA Science Inventory

    Various statistical methods were applied to spatially discrete data from 14 intensively sampled small estuarine systems in the mid-Atlantic U.S. The number of sites per system ranged from 6 to 37. The surface area of the systems ranged from 1.9 to 193.4 km2. Parameters examined ...

  19. ASSESSING THE HYDROGEOLOGIC CLASSIFICATION SYSTEM IN MID-ATLANTIC COASTAL PLAIN STREAMS USING BENTHIC MACROINVERTEBRATES

    EPA Science Inventory

    Assessing classification systems that describe natural variation across regions is an important first step for developing indicators. We evaluated a hydrogeologic framework for first order streams in the mid-Atlantic Coastal Plain as part of the LIPS-MACS (Landscape Indicators f...

  20. INDICATORS OF CHANGE IN MID-ATLANTIC WATERSHEDS, AND CONSEQUENCES IN UPPER CHESAPEAKE BAY

    EPA Science Inventory

    The rate of change of atmospheric temperature in the Northern Hemisphere in the past century relative to the preceding millennium strongly suggests that we are in a period of rapid global climate change. The mid-Atlantic region is quite sensitive to larger-scale climate variation...

  1. 90-METER DIGITAL ELEVATION MODEL (DEM) FOR THE MID-ATLANTIC INTEGRATED ASSESSMENT (MAIA) STUDY AREA

    EPA Science Inventory

    This data set is a geographic information system (GIS) coverage of the 90-meter digital elevation model (DEM) for the United States Environmental Protection Agency (USEPA) Mid-Atlantic Integrated Assessment (MAIA) Project region. The coverage was produced using US Geological Su...

  2. Mid-Atlantic Region Special Education Instructional Materials Center. Final Technical Report.

    ERIC Educational Resources Information Center

    Cottrell, Raymond S.; Carter, Robert

    The final report of the Mid-Atlantic Region Special Education Instructional Materials Center (MAR-SEIMC) describes field services, information services, library services, and research and evaluation activities conducted from 1967 to August 1974. It is explained that 39 affiliate centers were established throughout Pennsylvania, New Jersey,…

  3. Ecological Condition of Coastal Ocean Waters Along the U.S. Mid-Atlantic Bight: 2006

    EPA Science Inventory

    This report presents the results of an assessment of ecological condition in coastal-ocean waters of the U.S. mid-Atlantic Bight (MAB), along the U.S. continental shelf from Cape Cod, MA and Nantucket Shoals to the northeast to Cape Hatteras to the south, based on sampling conduc...

  4. IMPACT OF CLIMATE VARIATION AND CHANGE ON MID-ATLANTIC REGION HYDROLOGY AND WATER RESOURCES

    EPA Science Inventory

    The sensitivity of hydrology and water resources to climate variation and climate change is assessed for the Mid-Atlantic Region (MAR) of the United States. Observed streamflow, groundwater, and water-quality data are shown to vary in association with climate variation. Projectio...

  5. EFFECTIVENESS OF STREAM AND RIPARIAN RESTORATION IN THE MID-ATLANTIC REGION

    EPA Science Inventory

    The USEPA-ORD-GWERD has research projects in several locations in the Mid-Atlantic in progress to evaluate the effectiveness of stream and riparian restoration, including Mine Bank Run (Baltimore Co., MD), Susquehanna watershed (York and Lancaster Co., PA), and Leipsic watershed ...

  6. INNOVATIVE ENVIRONMENTAL EDUCATION CONTRIBUTES TO IMPROVED MANAGEMENT PRACTICES IN THE MID-ATLANTIC

    EPA Science Inventory

    EPA and other federal agencies have conducted considerable research in the Mid-Atlantic region. EPA's Science to Achieve Results (STAR) program funds academic scientists and engineers to conduct complementary research. Some of the research results are being used, but there is a...

  7. Satellite-derived coastal ocean and estuarine salinity in the Mid-Atlantic

    NASA Astrophysics Data System (ADS)

    Geiger, Erick F.; Grossi, Matthew D.; Trembanis, Arthur C.; Kohut, Josh T.; Oliver, Matthew J.

    2013-07-01

    Coastal salinity is a basic oceanographic property that is not routinely estimated by satellites. Efforts to measure ocean salinity from space are designed for large scale open ocean environments, not coastal regions. In the Mid-Atlantic coastal ocean, salinity is critical for understanding circulation patterns, river plumes, and transport, which in turn impact the status of the ecosystem. However, the spatial and temporal coverage of in situ salinity measurements in this region are sparse and do not synoptically capture salinity in the coastal ocean. We compiled ˜2 million salinity records from four regional research vessels between the years 2003-2008 and found ˜9 thousand salinity records that could be adequately matched to MODIS-Aqua data. We show that the spectral shape of water-leaving radiance and sea surface temperature are most correlated with in situ salinity. Four neural network models designed to predict salinity were developed for the Mid-Atlantic coastal region and three of its major estuaries (Hudson, Delaware, and Chesapeake). Our models predict salinity with RMS errors between 1.40psu and 2.29psu, which are much less than the null model ranges (4.87-10.08psu) and the natural range of the system (0-32psu). Seasonal climatologies for the Chesapeake, Delaware, and Mid-Atlantic regions based on these models are fresher than the existing NODC climatologies. We also found significant freshening trends in the Mid-Atlantic over a 6 year period.

  8. The Mid-Atlantic Wetland Conservation Effects Assessment Project: Ecosystem Services, Conservation Practices, and Synergistic Monitoring

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Mid-Atlantic Region of the eastern U.S. is characterized by a diversity of coastal and freshwater wetland ecosystems that humans and other species depend upon. Ecosystem services provided by wetlands include the regulation of runoff and floodwaters, habitat for many unique organisms, pollutant r...

  9. 76 FR 68745 - DC Energy, LLC; DC Energy Mid-Atlantic, LLC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-07

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission DC Energy, LLC; DC Energy Mid-Atlantic, LLC v. PJM Interconnection, L.L.C... Federal Energy Regulatory Commission (Commission), 18 CFR 385.206 (2011), DC Energy, LLC (DC Energy)...

  10. MULTI-RESOLUTION LAND CHARACTERISTICS FOR THE MID-ATLANTIC INTEGRATED ASSESMENT (MAIA) STUDY AREA

    EPA Science Inventory

    This data set is a Geographic Information System (GIS) coverage of the land use and land cover for the United States Environmental Protection Agency (USEPA) Mid-Atlantic Integrated Assessment (MAIA) Project region. The coverage was produced using 1988, 1989, 1991,1992, and 1993...

  11. A REGIONAL SCALE TOXICITY ASSESSMENT OF SEDIMENT IN THE MID-ATLANTIC AND SOUTHERN ROCKIES, USA

    EPA Science Inventory

    As part of the Environmental Monitoring and Assessment Program (EMAP), sediment samples were collected to assess toxicity on a regional scale in streams and rivers in the Mid-Atlantic U.S. in 1994, 1997 and 1998, and in the Colorado Rocky Mountains in 1994 and 1995. Sample sites...

  12. A SURVEY OF FISH CONTAMINATION IN SMALL WADEABLE STREAMS IN THE MID-ATLANTIC REGION

    EPA Science Inventory

    In 1993 and 1994, fish tissue samples were collected from first, second and third order streams in the Mid-Atlantic Region of the United States.The tissue samples were prepared from whole fish from prioritized lists of Small Target Species and Large Target Species. The two types ...

  13. MID-ATLANTIC COASTAL STREAMS STUDY: STATISTICAL DESIGN FOR REGIONAL ASSESSMENT AND LANDSCAPE MODEL DEVELOPMENT

    EPA Science Inventory

    A network of stream-sampling sites was developed for the Mid-Atlantic Coastal Plain (New Jersey through North Carolina) as part of collaborative research between the U.S. Environmental Protection Agency and the U.S. Geological Survey. A stratified random sampling with unequal wei...

  14. MID-ATLANTIC COASTAL STREAMS STUDY: STATISTICAL DESIGN FOR REGIONAL ASSESSMENT AND LANDSCAPE MODEL DEVELOPMENT

    EPA Science Inventory

    A network of stream-sampling sites was developed for the Mid-Atlantic Coastal Plain (New Jersey through North Carolina) a collaborative study between the U.S. Environmental Protection Agency and the U.S. Geological Survey. A stratified random sampling with unequal weighting was u...

  15. Harvesting Strawberries from Fall to Spring in the mid-Atlantic Region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the mid-Atlantic coast region, there is interest in meeting market demand for locally produced fresh strawberries from September to April by using high tunnels and heated greenhouses. But, varieties that can produce high quality fruit or practical methods to produce plants that will flower and f...

  16. DEVELOPMENT OF AN INDEX OF BIOTIC INTEGRITY FOR THE MID-ATLANTIC HIGHLANDS REGION

    EPA Science Inventory

    From 1993 to 1996, fish assemblage data were collected from 309 wadeable streams in the U.S. Mid-Atlantic Highlands region as part of the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program. Stream sites were selected with a probabilistic sampl...

  17. IMPACTS OF CLIMATE VARIATION AND CHANGE ON MID-ATLANTIC REGION HYDROLOGY

    EPA Science Inventory

    This study analyzes periodic variations in the climate of the mid-Atlantic Region over the last 100 years and uses general circulation models (GCMs) to project major climate trends for the next hundred years. Historical data include the Palmer Drought Severity Index (PDSI) for th...

  18. APPLICATION OF A MULTIPURPOSE UNEQUAL-PROBABILITY STREAM SURVEY IN THE MID-ATLANTIC COASTAL PLAIN

    EPA Science Inventory

    A stratified random sample with unequal-probability selection was used to design a multipurpose survey of headwater streams in the Mid-Atlantic Coastal Plain. Objectives for data from the survey include unbiased estimates of regional stream conditions, and adequate coverage of un...

  19. CHLORDANES IN THE MID-ATLANTIC ATMOSPHERE: NEW JERSEY 1997-1999

    EPA Science Inventory

    To characterize the atmospheric dynamics and behavior of chlordane compounds in the mid-Atlantic region of the United States, atmospheric concentrations were measured in 1997-1999 at three New Jersey locations as part of the New Jersey Atmospheric Deposition Network (NJADN) pro...

  20. INTEGRATION OF COASTAL ENVIRONMENTAL INDICATORS FOR THE U.S. MID-ATLANTIC REGION

    EPA Science Inventory

    The Mid-Atlantic Integrated Assessment (MAlA) Project began in 1994 as a partnership between USEPA's Region III Office and Office of Research and Development. This multi-year initiative was envisioned to: (1) improve the quality of environmental science and promote the use of sou...

  1. MID-ATLANTIC INTEGRATED ASSESSMENT (MAIA) STATE OF THE FLOWING WATERS REPORT

    EPA Science Inventory

    This assessment serves the purpose of a report card on the state of streams and rivers in the Mid-Atlantic region. It combines data from two sample surveys of flowing waters conducted in the region by the U.S. Environmental Protection Agency during the period 1993-98. Two unique...

  2. VULNERABILITY OF ECOSYSTEMS OF THE MID-ATLANTIC REGION, USA, TO CLIMATIC CHANGE

    EPA Science Inventory

    Changes in the distribution of vegetation in the mid-Atlantic region of the United States were explored for two climate-change scenarios. The equilibrium vegetation ecology (EVE) model was used to project the distribution of life forms and to combine these into biomes for a doubl...

  3. ASSOCIATIONS BETWEEN NAO VARIBILITY AND U.S. MID-ATLANTIC REGION HYDROCLIMATOLOGY

    EPA Science Inventory

    Variability in the climate of the US Mid-Atlantic Region is associated with larger scale variability in the El Nino-Southern Oscillation (ENSO), the Pacific North American (PNA) teleconnection pattern, and the North Atlantic Oscillation (NAO). Collectively, these three large-scal...

  4. CONDITION OF THE MID ATLANTIC ESTUARIES: PRODUCTION OF A STATE OF THE ENVIRONMENT REPORT

    EPA Science Inventory

    The U.S. Environmental Protection Agency has released a report entitled Condition of the Mid-Atlantic Estuaries. That report summarizes the findings of several studies conducted by federal and state agencies and academic institutions in Chesapeake Bay, Delaware Estuary, and the c...

  5. Nitrous oxide emissions from natural, converted, and restored wetlands of the Mid-atlantic Coastal Plain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    On the Mid-Atlantic Coastal Plain of the United States, wetlands have often been drained and converted to agricultural use. Recent efforts by the Natural Resources Conservation Service have attempted to restore some of the prior-converted farmland back to their natural state. These restored wetlands...

  6. SELF-ORGANIZING MAPS FOR INTEGRATED ASSESSMENT OF THE MID-ATLANTIC REGION

    EPA Science Inventory

    A. new method was developed to perform an environmental assessment for the
    Mid-Atlantic Region (MAR). This was a combination of the self-organizing map (SOM) neural network and principal component analysis (PCA). The method is capable of clustering ecosystems in terms of envi...

  7. THE POTENTIAL IMPACTS OF CLIMATE CHANGE ON THE MID-ATLANTIC COASTAL REGION

    EPA Science Inventory

    This paper assesses the potential impacts of climate change on the mid-Atlantic coastal (MAC) region of the United States. In order of increasing uncertainty, it is projected that sea level, temperature and streamflow will increase in the MAC region in response to higher levels o...

  8. Mid-Atlantic Regional Training Center for Residential Construction Trades. Final Program Evaluation Report.

    ERIC Educational Resources Information Center

    Wasdyke (R. G.) & Associates, Annapolis, MD.

    A group of partners headed by the Home Builders Institute (HBI) created the Mid-Atlantic Regional Training (MART) Center for Residential Construction, with a primary focus on providing education and training services related to the masonry and carpentry trades at existing institutions in the District of Columbia, Maryland, Virginia, and West…

  9. DECISION TOOL FOR RIPARIAN ECOSYSTEM MANAGMENT IN THE MID-ATLANTIC HIGHLANDS

    EPA Science Inventory

    In the Canaan Valley Highlands of the Mid-Atlantic, riparian zone restoration has been identified as a critical watershed management practice not only for the ecosystem services provided but also for the potential socioeconomic growth from environmental investment and job creatio...

  10. ESTIMATING STREAMFLOW AND ASSOCIATED HYDRAULIC GEOMETRY, THE MID-ATLANTIC REGION, USA

    EPA Science Inventory

    Methods to estimate streamflow and channel hydraulic geometry were developed for ungaged streams in the Mid-Atlantic Region. Observed mean annual streamflow and associated hydraulic geometry data from 75 gaging stations located in the Appalachian Plateau, the Ridge and Valley, an...

  11. Trophic Structure Over the Northern Mid-Atlantic Ridge: The Bathypelagic Zone Really Matters

    EPA Science Inventory

    We present preliminary results and ongoing efforts to characterize the trophic structure and energy flow of the pelagic ecosystems of the northern Mid-Atlantic Ridge (MAR), from Iceland to the Azores. This study is one component of the international CoML field project MAR-ECO (ww...

  12. GLOBAL CHANGE RESEARCH NEWS #2: MID-ATLANTIC REGIONAL ASSESSMENT (MARA)

    EPA Science Inventory

    As part of this National Assessment effort mandated by the Global Change Research Act of 1990, EPA's Global Change Research Program is sponsoring the Mid-Atlantic Regional Assessment (MARA). With EPA sponsorship, a multi-disciplinary team of faculty members is leading the first a...

  13. 77 FR 65363 - New England Fishery Management Council (NEFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-26

    ... Fisheries Science Center's (NEFSC) Science and Research Director will present an overview of the NEFSC draft... Fisheries Science Center and Mid-Atlantic Fishery Management Council liaisons, NOAA General Counsel... Atmospheric Administration (NOAA), Commerce. ACTION: Notice of a public meeting. SUMMARY: The New...

  14. 78 FR 2370 - New England Fishery Management Council (NEFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-11

    ... Science Center and Mid- Atlantic Fishery Management Council liaisons, NOAA General Counsel... allocations (based on Framework 2 provisions), research set- asides, set-asides for fixed gear fisheries in..., January 30, 2013 The Council will receive a report from the Northeast Fisheries Science Center...

  15. WATERSHED HEALTH ASSESSMENT TOOLS INVESTIGATING FISHERIES WHAT IF VERSION 2 A MANAGER'S GUIDE TO NEW FEATURES

    EPA Science Inventory

    The Canaan Valley Institute (CVI) is dedicated to addressing the environmental problems in the Mid-Atlantic Highlands (MAH). Their goal is to develop and implement solutions to restore damaged areas and protect aquatic systems. In most wadeable streams of the Mid-Atlantic Highlan...

  16. IPOD-USGS multichannel seismic reflection profile from Cape Hatteras to the Mid-Atlantic Ridge

    USGS Publications Warehouse

    Grow, John A.; Markl, Rudi G.

    1977-01-01

    A 3,400-km-long multichannel seismic-reflection profile from Cape Hatteras to the Mid-Atlantic Ridge was acquired commercially under contract to the National Science Foundation and the U.S. Geological Survey. These data show evidence for massive erosion of the continental slope, diapirs at the base of the continental slope, and mantle reflections beneath the Hatteras Abyssal Plain.

  17. An oilspill risk analysis for the Mid-Atlantic Outer Continental Shelf lease area

    USGS Publications Warehouse

    Smith, Richard Allmon; Slack, James Richard; Davis, Robert K.

    1976-01-01

    An oilspill risk analysis was conducted to determine relative environmental impacts of developing oil in different regions of the Mid-Atlantic Outer Continental Shelf lease area. The study analyzed probability of spills, likely path of pollutants from spills, and locations in space and time of recreational and biological resources likely to be vulnerable. These results are combined to yield estimates of the overall oilspill risk associated with development of the lease area. (Woodard-USGS)

  18. PIPELINES, TRANSMISSION LINES, AND MISCELLANEOUS TRANSPORTATION FEATURES DIGITAL LINE GRAPHS FOR THE MID-ATLANTIC INTEGRATED ASSESSMENT (MAIA) STUDY AREA

    EPA Science Inventory

    This data set is a geographic information system (GIS) coverage of pipelines, transmission lines, and miscellaneous transportation features for the United States Environmental Protection Agency (USEPA) Mid-Atlantic Integrated Assessment (MAIA) Project region. The coverage was p...

  19. 78 FR 57377 - Mid-Atlantic Hydro, LLC; Notice of Competing Preliminary Permit Application Accepted for Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-18

    ...: Kristina Johnson, Mid-Atlantic Hydro, LLC, 5425 Wisconsin Avenue, Suite 600, Chevy Chase, MD 20815; phone...) 502-8659 (TTY). In lieu of electronic filing, please send a paper copy to: Secretary, Federal...

  20. DEVELOPMENT AND EVALUATION OF A MACROINVERTEBRATE BIOTIC INTEGRITY INDEX (MBII) FOR REGIONALLY ASSESSING MID-ATLANTIC HIGHLANDS STREAMS

    EPA Science Inventory

    The multimetric Macroinvertebrate Biotic Integrity Index (MBII) was developed from data collected at 574 wadeable stream reaches in the Mid-Atlantic Highlands region (MAHR) by the USEPA's Environmental Monitoring and Assessment Program (EMAP). Over 100 candidate metrics were eval...

  1. Particulate Matter Pollution and its Regional Transport in the Mid-Atlantic States

    NASA Astrophysics Data System (ADS)

    He, H.; Goldberg, D. L.; Hembeck, L.; Canty, T. P.; Vinciguerra, T.; Ring, A.; Salawitch, R. J.; Dickerson, R. R.

    2015-12-01

    Particulate matter (PM) causes negative effects on human health, impair visibility in scenic areas, and affect regional/global climate. PM can be formed through chemical changes of precursors, including biogenic VOCs and anthropogenic SO2 and NOx often from fossil fuel combustion. In the past decades, PM pollution in the US has improved substantially. However, some areas in the Mid-Atlantic States are still designated as 'moderate' nonattainment by EPA. We utilize datasets obtained during the NASA 2011 DISCOVER-AQ campaign to characterize the composition and distribution of summertime PM pollution in the Mid-Atlantic States. Aircraft measurements and OMI satellite retrieval of major anthropogenic precursors (NO2 and SO2) are analyzed to investigate the regional transport of PM precursors from upwind sources. We compare PM concentration and chemical composition observed during the field campaign to CMAQ simulations with the latest EPA emission inventory. Specifically, we focus on the secondary organic aerosol (SOA) chemistry in CMAQ simulations using various biogenic VOCs estimates from the MEGAN and BEIS models. Airborne PM observations including PILS measurements from DISCOVER-AQ campaign and OMI retrievals of HCHO are also used to validate and improve the representation of SOA chemistry and PM pollution within CMAQ. The comparison reveals the source and evolution of PM pollution in the Mid-Atlantic States.

  2. Feeding Ecology of Coryphaenoides rupestris from the Mid-Atlantic Ridge

    PubMed Central

    Bergstad, Odd Aksel; Gjelsvik, Guro; Schander, Christoffer; Høines, Åge S.

    2010-01-01

    The Macrourid fish roundnose grenadier, Coryphaenoides rupestris, is one of the most common benthopelagic fishes on the northern mid-Atlantic Ridge. The ecology of the species is comparatively well studied in continental slope waters of the North Atlantic, but not on the mid-Atlantic Ridge, which is a central mid-ocean area of its distribution. In total, 166 specimens from the RV G.O. Sars cruise in July 2004 were examined. The diet mainly comprised cephalopods, pelagic shrimps and fish. Pelagic and benthopelagic copepods were the most numerous prey, but did not contribute much on a weight basis. Cephalopods were by far the most important prey of the small grenadiers, while shrimps and fish became increasingly significant with increasing size. Previous studies from other areas have also found pelagic prey to be important, but in contrast to this study, cephalopods were generally of less importance. The study was an element of more wide-ranging food-web studies of the mid-Atlantic Ridge macro- and megafauna communities within the international MAR-ECO project. PMID:20454674

  3. Quantitative relationships between watershed-scale stressors and estuarine condition for mid-Atlantic region

    SciTech Connect

    Paul, J.F.; Hale, S.S.; Comeleo, R.L.; Copeland, J.; August, P.V.

    1995-12-31

    A pilot project has been conducted that developed quantitative relationships between watershed-scale (landscape) stressors and sediment contamination for sub-estuaries within Chesapeake Bay. The landscape stressors, land use patterns (derived from classified, contemporary satellite imagery) and point source pollution, were spatially analyzed for each individual watershed of 25 sub-estuaries using a geographic information system. Sediment contamination data for the sub-estuaries, available from the Environmental Monitoring and Assessment Program (EMAP), were statistically reduced to one principal component for the metals and organics. Non-parametric statistical techniques were used to develop empirical relationships between sediment contamination and developed land (positive), herbaceous land (negative) and point source loadings (positive). These analyses have been extended to (1) include approximately 80 subestuaries across the mid-Atlantic region for which EMAP data were available, and (2) relate landscape stressors with estuarine condition. The measure of estuarine condition was an index of benthic quality developed by EMAP. The only available land use data set for the entire mid-Atlantic region was from US Geological Survey Land Use Data Analysis database, which is of 1970s vintage. Because of the dramatic differences in spatial area of the sub-estuaries in the mid-Atlantic region, adjustments for differing hydrologic regimes had to be factored into the analysis. Results indicate that it is possible to develop relationships between watershed-scale stressors and estuarine condition across large geographic regions.

  4. 75 FR 56994 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-17

    ...) set 2011 SSC schedule, (8) discussed development of Industry Advisory Panel Reports, and (9) discussed formation of SSC Ecosystem Subcommittee and development of ecosystem terms of reference for the Council. Details about participation in the Webinar will be posted on the Council's website which can be...

  5. 77 FR 55192 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-07

    ... INFORMATION: The primary issues for the SSC meeting include: Developing 2013-17 ABC recommendations for the Council for spiny dogfish; considerations for setting multi-year ABC specifications; ABC/OY control rule... to clarify the SSC's 2012 butterfish ABC recommendations if necessary. Although non-emergency...

  6. 77 FR 12814 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-02

    ...-5255. SUPPLEMENTARY INFORMATION: The primary purpose of the SSC meeting includes: 2012-14 ABC...; discussion of the peer review of the Management Strategy Evaluation Study of the ABC Control Rules; development of criteria for establishing multi-year ABC recommendations; and development of technical...

  7. 78 FR 13867 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-01

    ... of Tilefish Industry AP Performance Report, (2) review information relevant to 2013-2014 Tilefish ABC recommendations, (3) SUN Subcommittee update on signpost development for multi-year ABC specifications, (4)...

  8. 75 FR 27990 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-19

    ... multi-disciplinary study looking at adaptation to climate change in a human-natural coupled system. The... management measures for Council consideration and action; and receive a presentation on Climate Change...

  9. 76 FR 3878 - Mid-Atlantic Fishery Management Council; Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-21

    ... Council (Council) and its Squid, Mackerel, Butterfish Committee with Advisors, its Surfclam/Ocean Quahog... INFORMATION: Tuesday, February 8, 2011 1 p.m. until 5 p.m.--The Squid, Mackerel, Butterfish Committee with... Committees and the Council itself are: Tuesday, February 8--The Squid, Mackerel, and Butterfish...

  10. 78 FR 26616 - Mid-Atlantic Fishery Management Council (Council); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-07

    ... potential changes to squid (longfin and Illex) assessment and management. DATES: The Narragansett, RI...: In January 2013, the Council held a workshop on squid (longfin and Illex) assessment and management... squid management more responsive to current conditions. A summary and additional materials from...

  11. 76 FR 16620 - Mid-Atlantic Fishery Management Council (MAFMC); Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-24

    ...) will meet with the Council's Squid, Mackerel, and Butterfish (SMB) Advisory Panel (AP). DATES: Thursday... Squid, Mackerel, and Butterfish. On Friday, April 15--The Joint Meeting of the Squid, Mackerel,...

  12. 77 FR 16811 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-22

    ... 5 to Squid, Mackerel, and Butterfish will be discussed. 10:30 a.m. until 11 a.m.--Framework 6 to Squid, Mackerel, and Butterfish will be discussed. 11 a.m. until 1 p.m.--The Council will hold its... vessel hold certification requirements in Framework 5 to the Squid, Mackerel, and Butterfish FMP...

  13. 75 FR 57904 - Mid-Atlantic Fishery Management Council (MAFMC); Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-23

    ... Squid, Mackerel, and Butterfish Committee will hold public meetings. DATES: The meetings will be held on... Dogfish Management Measures for 2011 and beyond will be discussed from 10 a.m. until 12 p.m. The Squid... measure recommendations for the 2011 fishing year and beyond. The Squid, Mackerel, and...

  14. 75 FR 56509 - Mid-Atlantic Fishery Management Council (MAFMC); Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-16

    ... Council's (MAFMC) Squid, Mackerel, and Butterfish Committee will hold a public meeting. DATES: Wednesday...-5255. SUPPLEMENTARY INFORMATION: The purpose of this Squid, Mackerel, and Butterfish Committee meeting is to begin the development of Amendment 14 to the Atlantic Mackerel, Squid, and Butterfish...

  15. 75 FR 20566 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-20

    ... Council's (MAFMC) Atlantic Mackerel, Squid, and Butterfish Monitoring Committee will hold a public meeting... Atlantic mackerel, Loligo and Illex squid and butterfish. Although non-emergency issues not contained...

  16. 78 FR 57620 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-19

    ..., the Science Report, Committee Reports, and conduct any continuing and/or new business. Agenda items by... Report, Science Report, Committee Reports, and conduct any continuing and/or new business. Although non.... Special Accommodations These meetings are physically accessible to people with disabilities. Requests...

  17. 76 FR 58782 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-22

    ..., Council Liaison Reports, Executive Director's Report, Science Report, Committee Reports, and any... Director's Report, the Science Report, Committee Reports, and any continuing and/or new business. Special Accommodations This meeting is physically accessible to people with disabilities. Requests for sign...

  18. 78 FR 70017 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-22

    ... Reports, the Executive Director's Report, the Science Report, Committee Reports, and conduct any... Council will receive a report of the National Science Foundation Coupled Natural and Human Systems Surfclam Study: Climate change and responses in a coupled marine system and an update on the Science...

  19. 76 FR 72906 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-28

    ..., Science Report, Committee Reports, and any continuing and/or new business. Agenda items by day for the... Science Report, Committee Reports, and any continuing and/or new business. Although non-emergency issues... meetings are physically accessible to people with disabilities. Requests for sign language...

  20. 77 FR 4013 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-26

    ... Report, the Executive Director's Report, the Science Report, Committee Reports, and conduct any... Report, the Executive Director's Report, Science Report, Committee Reports, and conduct any continuing and/or new business. Special Accommodations This meeting is physically accessible to people...

  1. 77 FR 70149 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-23

    ... liaison, organizational, Executive Director, Science, and Committee Reports. From 11:30 a.m. until 12 p.m... will discuss the next steps for completing the draft strategic plan, finalize Science and Data and..., organizational, Executive Director, Science, and Committee Reports. The Council will receive a presentation...

  2. 76 FR 45232 - Mid-Atlantic Fishery Management Council (MAFMC); Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-28

    ... Director's Report, Science Report, Committee Reports, and any continuing and/or new business. Agenda items... SAW/SARC 52 report, the Executive Director's Report, the Science Report, Committee Reports, and any continuing and/ or new business. Special Accommodations This meeting is physically accessible to people...

  3. 50 CFR 648.21 - Mid-Atlantic Fishery Management Council risk policy.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... rules in § 648.20(a) through (d) to ensure the MAFMC's preferred tolerance for the risk of overfishing... to have an atypical life history, the maximum probability of overfishing as informed by the OFL... higher (i.e., the stock is at BMSY or higher). The maximum probability of overfishing shall...

  4. 77 FR 55812 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ... Atmospheric Administration (NOAA), Commerce. ACTION: Notice of a public meeting. SUMMARY: The Spiny Dogfish..., Dover, DE 19901; telephone: (302) 526-5255. SUPPLEMENTARY INFORMATION: The Spiny Dogfish...

  5. 75 FR 53952 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-02

    ... Council's (MAFMC) Spiny Dogfish Monitoring Committee will hold a meeting. DATES: The meeting will be held... dogfish for fishing years 2011-15. Although non-emergency issues not contained in this agenda may...

  6. 75 FR 55743 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-14

    ... assessment information and specify overfishing level and acceptable biological catch for spiny dogfish for... spiny dogfish for fishing years 2011-15; (3) progress report on Management Strategy Evaluation study;...

  7. 78 FR 27189 - Mid-Atlantic Fishery Management Council (Council); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-09

    ... MSB specifications. The first meeting will be in Gloucester, MA and the second will be via webinar. DATES: The first meeting will be May 23, 2013, starting at 10 a.m. and ending by 5 p.m. The second... in Gloucester, MA and the second will be via webinar. The May ] 23 Gloucester meeting will focus...

  8. 78 FR 17358 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-21

    .... until 3 p.m.--A Forage Fish Workshop will be held. Agenda items by day for the Council's Committees and... A Forage Fish Workshop will be held to discuss the key issues relevant to forage fish assessment and management under the MSA. A panel of experts will discuss the role of forage species within ecosystems...

  9. 76 FR 12943 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-09

    ... to develop a roadmap for the implementation of the Visioning and Strategic Planning Project. The roadmap will detail how the Council solicits stakeholder input and then incorporates that input into...

  10. 50 CFR 648.21 - Mid-Atlantic Fishery Management Council risk policy.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., best available science indicates that stock biomass is stable or increasing; and the SSC provides a determination that, based on best available science, the recommended increase to the ABC is not expected...

  11. 78 FR 21915 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-12

    ... Atmospheric Administration (NOAA), Commerce. ACTION: Notice of a public meeting. SUMMARY: The Scientific and... arising after publication of this notice that require emergency action under section 305(c) of...

  12. 78 FR 23223 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-18

    ... Atmospheric Administration (NOAA), Commerce. ACTION: Notice of a public meeting. SUMMARY: The Scientific and... publication of this notice that require emergency action under section 305(c) of the Magnuson-Stevens...

  13. 77 FR 39998 - Mid-Atlantic Fishery Management Council; Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-06

    ...), Commerce. ACTION: Notice of public meetings. SUMMARY: The Scientific and Statistical Committee (SSC) and... publication of this notice that require emergency action under section 305(c) of the Magnuson-Stevens...

  14. 78 FR 53731 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-30

    ... Atmospheric Administration (NOAA), Commerce. ACTION: Notice of public meeting. SUMMARY: The Scientific and... issues specifically identified in this notice and any issues arising after publication of this...

  15. 76 FR 26252 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-06

    ... Atmospheric Administration (NOAA), Commerce. ACTION: Notice of a public meeting. SUMMARY: The Scientific and... restricted to those issues specifically listed in this notice and any issues arising after publication...

  16. 77 FR 26515 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-04

    ...), Commerce. ACTION: Notice of a public meeting. SUMMARY: The Scientific and Statistical Committee (SSC) of... arising after publication of this notice that require emergency action under section 305(c) of...

  17. 77 FR 77036 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-31

    ... Atmospheric Administration (NOAA), Commerce. ACTION: Notice of public meeting. SUMMARY: The Scientific and... arising after publication of this notice that require emergency action under section 305(c) of...

  18. 75 FR 2488 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-15

    ... Council's (MAFMC) Scientific and Statistical Committee (SSC) will hold a public meeting. DATES: The... specifically identified in this notice and any issues arising after publication of this notice that...

  19. 78 FR 67128 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-08

    ... Summer Flounder, Scup, and Black Sea Bass Advisory Panel will hold public meetings. DATES: The meeting... 255. SUPPLEMENTARY INFORMATION: The Summer Flounder, Scup, and Black Sea Bass Advisory Panel will... sea bass measures from 3:30 p.m. to 4:30 p.m. Although non-emergency issues not contained in...

  20. 77 FR 66586 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-06

    ..., Scup, and Black Sea Bass Advisory Panel will hold a public meeting. DATES: The meeting will be held on.... SUPPLEMENTARY INFORMATION: The Summer Flounder, Scup, and Black Sea Bass Advisory Panel will discuss potential... provisions of Amendment 9 to the Summer Flounder, Scup and Black Sea Bass FMP. Based on input from...

  1. 77 FR 66586 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-06

    ..., Scup, and Black Sea Bass Advisory Panel will hold a public meeting. DATES: The meeting will be held on... 255. SUPPLEMENTARY INFORMATION: The Summer Flounder, Scup, and Black Sea Bass Advisory Panel will... measures will be discussed from 1 p.m. to 2 p.m., scup measures from 2 p.m. to 3 p.m., and black sea...

  2. 76 FR 30920 - Mid-Atlantic Fishery Management Council (MAFMC); Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-27

    ... Council (Council) and its Research Set-Aside (RSA) Committee, its Ecosystems and Ocean Planning Committee, its Executive Committee, its Surfclam, Ocean Quahog, Tilefish Committee, its Visioning Committee, and... RSA Committee will hold an OPEN meeting from 2 p.m. until 3 p.m. The Ecosystems and Ocean...

  3. 75 FR 26920 - Mid-Atlantic Fishery Management Council; Spiny Dogfish Amendment 3 Scoping Process

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-13

    ... Register on August 5, 2009 (74 FR 39063). This NOI solicited comments for the following issues to be... issues not listed in the original NOI. DATES: Written comments must be received on or before 5 p.m., EST... fishing impact analysis that were originally done in the 1999 FMP. It will also include any...

  4. 76 FR 9553 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-18

    ...) will meet with the Council's Atlantic Mackerel, Squid and Butterfish Industry Advisory Panel (AP... industry advisors concerning development of an AP Performance Report. Although non-emergency issues...

  5. 76 FR 14378 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-16

    ... Council's (MAFMC) River Herring and Shad Ad Hoc Committee will hold a webinar meeting. DATES: The meeting... available to the Council for management of River Herring (blueback and alewife) and Shad (American...

  6. 75 FR 20567 - Mid-Atlantic Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-20

    ... Council's (MAFMC) Scientific and Statistical Committee (SSC) will hold a public meeting. DATES: The... reference for this meeting include: (1) Review stock assessment information and specify overfishing...

  7. 76 FR 39074 - Mid-Atlantic Fishery Management Council; Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-05

    ... Black Sea Bass Monitoring Committees will meet on Friday, July 29, 2010 from 8:30 a.m. to 5 p.m... Black Sea Bass Monitoring Committees will hold public meetings. DATES: The SSC meeting will be held... and acceptable biological catch (ABC) for bluefish, summer flounder, scup, and black sea bass for...

  8. 78 FR 65973 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-04

    ..., and Black Sea Bass Monitoring Committee will hold a public meeting. DATES: The meeting will be held on Friday, November 22, 2013, from 9 a.m. to 5 p.m. See SUPPLEMENTARY INFORMATION for meeting agenda... Summer Flounder, Scup, and Black Sea Bass Monitoring Committee will meet to recommend...

  9. 75 FR 72791 - Mid-Atlantic Fishery Management Council; Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-26

    ... on the status of MAFMC's FMPs, Committee Reports, and any continuing and/ or new business. Agenda... Reports, the Executive Director's Report, an update on the status of the Council's FMPs, Committee...

  10. 75 FR 44226 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-28

    ... the status of MAFMC's FMPs, Committee Reports, and any continuing and/ or new business. Agenda items..., the Executive Director's Report, an update on the status of the Council's FMPs, Committee Reports,...

  11. 78 FR 5421 - Mid-Atlantic Fishery Management Council (MAFMC); Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-25

    ... for the Deep Sea Corals Amendment. On Thursday February 14--A presentation on the new Council Web site... Plan (Deep Sea Corals Amendment) and review alternatives to be included in the Amendment. The Council... Butterfish FMP (Deep Sea Corals). On Thursday, February 14--The Council will hold its regular...

  12. 75 FR 3897 - Mid-Atlantic Fishery Management Council; Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-25

    ... a Clam Processing Plant in Milford, DE. Thursday, February 11, 2010 8 a.m. -- The Council will... coast. The Council will then tour a Clam Processing Plant in Milford, DE on Wednesday afternoon....

  13. 77 FR 22285 - Mid-Atlantic Fishery Management Council; Public Hearings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-13

    ... available via webinar. For specific locations and webinar access, see SUPPLEMENTARY INFORMATION below...) Implement Effective RH/S Catch Monitoring; (B) Reduce RH/S Bycatch and/or Catch; and (C) Consider if RH/S...) 208-0002. May 16, 2012: 6-8 p.m.; Available via Internet webinar (...

  14. Nitrate and selected pesticides in ground water of the Mid-Atlantic region

    USGS Publications Warehouse

    Ator, Scott W.; Ferrari, Matthew J.

    1997-01-01

    Data from more than 850 sites were compiled and analyzed to document the occurrence of nitrate and pesticides in ground water of the Mid-Atlantic region as part of the Mid-Atlantic Integrated Assessment program of the U.S. Environmental Protection Agency. Only those data collected by the U.S. Geological Survey as part of regional networks between October 1985 and September 1996 (inclusive) were used in the analyses, and the data were examined to ensure analytical results are not biased toward sites at the same location or sites sampled multiple times during this period. Regional data are available for most of the Mid-Atlantic region but large spatial gaps in available data do exist. Nitrate was detected in nearly three-quarters of the samples for which it was analyzed, commonly at levels that suggest anthropogenic sources. Ten percent of samples contained nitrate at concentrations exceeding the Federal Maximum Contaminant Level (MCL) of 10 milligrams per liter as nitrogen. Pesticide compounds (including atrazine, metolachlor, prometon, simazine, and desethylatrazine, an atrazine degradate) were detected in about half of the samples for which they were analyzed, but rarely at concentrations exceeding established MCL?s. The most commonly detected pesticide compounds were desethylatrazine and atrazine. The occurrence of nitrate and pesticides in ground water of the Mid-Atlantic region is related to land cover and rock type. Likely sources of nitrate and pesticides to ground water include agricultural and urban land-use practices; rock type affects the movement of these compounds into and through the ground-water system. Nitrate concentrations in the compiled data set are significantly higher in ground water in agricultural areas than in urban or forested areas, but concentrations in areas of row crops are statistically indistinguishable from those in areas of pastures. Detection frequencies of atrazine, desethylatrazine, and simazine are indistinguishable among urban

  15. Patterns and Rates of Historical Shoreline Change along the New England and Mid-Atlantic Coasts

    NASA Astrophysics Data System (ADS)

    Kratzmann, M. G.; Hapke, C. J.; Himmelstoss, E. A.; List, J. H.; Thieler, E. R.

    2010-12-01

    The U.S. Geological Survey is analyzing historical shoreline changes along open-ocean shores of the conterminous United States and parts of Hawaii, Alaska and the Great Lakes to calculate trends and rates of shoreline movement. This accurate and detailed coastal change information is necessary as growing coastal communities and infrastructure are threatened by erosion. Repeatable analytical methods were developed for shoreline movement calculations to facilitate periodic updates of coastal change in a systematic and internally consistent manner. The U.S. New England and Mid-Atlantic coasts from Maine to Virginia are the most recent to be completed in the National Assessment of Shoreline Change project. Shorelines from the 1800s through 2007 were derived from historical maps, orthophotos, and airborne lidar (1997-2007). All shoreline change rates are calculated using the Digital Shoreline Analysis System (DSAS) developed by the U.S. Geological Survey. Long-term rates of change are calculated using linear regression through all available shorelines (n = 4 to 12) for the full period of record (100-150 years). Short-term rates of change are calculated for the most recent 25-30 years, using the end-point method. Shoreline change rates were calculated for 78% of the 1360 km of coast in the study area. Complete coverage is lacking due to data gaps, as well as locations (rocky coastlines, large embayments, and beaches) where robust data are unavailable. The average rates of shoreline change for New England and the Mid-Atlantic are erosional, with higher erosion rates observed in the long-term than in the short-term. The average rates of long- and short-term shoreline change in New England (Maine, New Hampshire, Massachusetts, Rhode Island) are -0.4 m/yr ± 0.1 m/yr and -0.2 ± 0.09 m/yr, respectively. The average long-term rate in the Mid-Atlantic (New York, New Jersey, Delaware, Maryland, Virginia) is -0.6 ± 0.1 m/yr and the short-term rate of change is -0.3 ± 0.1 m

  16. 77 FR 51858 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-27

    ..., NMFS published a proposed rule (76 FR 66260) that included the Mid-Atlantic Fishery Management Council... butterfish specifications (March 21, 2012; 77 FR 16472) that temporarily reinstated the status quo butterfish..., 2011; 76 FR 66260), there is no need to re-propose these final specifications. NMFS used the...

  17. Summary of the Mid-Atlantic conference on small-scale hydropower in the Mid-Atlantic states: resolution of the barriers impeding its development

    SciTech Connect

    Not Available

    1980-05-01

    The workshop was conducted to bring together interested persons to examine and discuss the major problems associated with small-scale hydroelectric dam development in the Mid-Atlantic region. The conference opened with an introductory panel which outlined the objectives and the materials available to conference participants. Two of the workshops discussed problems and policy responses raised by state and Federal regulation. The other two workshops concerned economic issues confronting small-scale hydro development and the operation and usefulness of the systems dynamics model under development by the Thayer School of Engineering at Dartmouth. Various Federal and state programs designed to stimulate small-scale hydro development were discussed. A plenary session completed the workshops.

  18. Recycling of construction debris as aggregate in the Mid-Atlantic Region, USA

    USGS Publications Warehouse

    Robinson, G.R., Jr.; Menzie, W.D.; Hyun, H.

    2004-01-01

    Reclaimed asphalt pavement (RAP) and portland cement concrete (RPCC) are abundant and available substitutes for natural aggregate in many areas. This paper presents an overview of factors that affect recycled aggregate cost, availability, and engineering performance, and the results of a survey of business practices in the Mid-Atlantic region. For RAP, processing costs are less than those for virgin natural aggregate. Use of efficient asphalt pavement stripping technology, on-site reclamation, and linked two-way transport of asphalt debris and processed asphalt paving mix between asphalt mix plants and paving sites has led to extensive recycling of asphalt pavement in the Mid-Atlantic region of the US. Most of the sites that recycle asphalt pavement (RAP) are located in or near urban areas close to important transportation corridors. RPCC is a viable aggregate source in urban settings where unit costs for processed aggregate from RPCC and natural aggregate are comparable. Disposal fees charged at RPCC recycling sites help defray processing costs and the significantly lower tipping fees at recycling sites versus landfill disposal sites encourage recycling of construction debris as aggregate. Construction contractors and construction debris recycling centers, many of which have the ability to crush and process concrete debris at the job site, produce most RPCC. Production of RPCC aggregate from construction debris that is processed on site using portable equipment moved to the construction site eliminates transportation costs for aggregate and provides an economic incentive for RPCC use. Processing costs, quality and performance issues, and lack of large quantities where needed limit RPCC use. Most RPCC suppliers in the Mid-Atlantic area are located in counties with population densities greater than 400 people/km2 (1036 people/mile2) and that have high unit-value costs and limited local availability of natural aggregate. ?? 2004 Published by Elsevier B.V.

  19. Sustainable use of flatfish resources: Addressing the credibility crisis in mixed fisheries management

    NASA Astrophysics Data System (ADS)

    Rijnsdorp, A. D.; Daan, N.; Dekker, W.; Poos, J. J.; Van Densen, W. L. T.

    2007-02-01

    Many flatfish species are caught in mixed demersal trawl fisheries and managed by Total Allowable Catch (TAC). Despite decades of fisheries management, several major stocks are severely depleted. Using the Common Fisheries Policy (CFP) as an example, the failure of mixed-fisheries management is analysed by focussing on: the management system; the role of science; the role of managers and politicians; the response of fisheries to management. Failure of the CFP management could be ascribed to: incorrect management advice owing to bias in stock assessments; the tendency of politicians to set the TAC well above the recommended level; and non-compliance of the fisheries with the management regulations. We conclude that TAC management, although apparently successful in some single-species fisheries, inevitably leads to unsustainable exploitation of stocks caught in mixed demersal fisheries as it promotes discarding of over-quota catch and misreporting of catches, thereby corrupting the basis of the scientific advice and increasing the risk of stock collapse. This failure in mixed demersal fisheries has resulted in the loss of credibility of both scientists and managers, and has undermined the support of fishermen for management regulations. An approach is developed to convert the TAC system into a system that controls the total allowable effort (TAE). The approach takes account of the differences in catch efficiency between fleets as well as seasonal changes in the distribution of the target species and can also be applied in the recovery plans for rebuilding specific components of the demersal fish community, such as plaice, cod and hake.

  20. Final Report of the Mid-Atlantic Marine Wildlife Surveys, Modeling, and Data

    SciTech Connect

    Saracino-Brown, Jocelyn; Smith, Courtney; Gilman, Patrick

    2013-07-01

    The Wind Program hosted a two-day workshop on July 24-25, 2012 with scientists and regulators engaged in marine ecological survey, modeling, and database efforts pertaining to the waters of the Mid-Atlantic region. The workshop was planned by Federal agency, academic, and private partners to promote collaboration between ongoing offshore ecological survey efforts, and to promote the collaborative development of complementary predictive models and compatible databases. The meeting primarily focused on efforts to establish and predict marine mammal, seabird, and sea turtle abundance, density, and distributions extending from the shoreline to the edge of the Exclusive Economic Zone between Nantucket Sound, Massachusetts and Cape Hatteras, North Carolina.

  1. Potential Economic Impacts from Offshore Wind in the Mid-Atlantic Region (Fact Sheet)

    SciTech Connect

    Keyser, D.; Tegen, S.; Flores, F.; Zammit, D.; Kraemer, M.; Miles, J.

    2014-01-01

    Offshore wind is a clean, renewable source of energy and can be an economic driver in the United States. To better understand the employment opportunities and other potential regional economic impacts from offshore wind development, the U.S. Department of Energy (DOE) funded research that focuses on four regions of the country. The studies use multiple scenarios with various local job and domestic manufacturing content assumptions. Each regional study uses the new offshore wind Jobs and Economic Development Impacts (JEDI) model, developed by the National Renewable Energy Laboratory. This fact sheet summarizes the potential economic impacts for the Mid-Atlantic region.

  2. Scrap tire management in the New York/Mid Atlantic region

    SciTech Connect

    Blumenthal, M.

    1995-05-01

    The Scrap Tire Management Council (STMC) is a North American tire manufactures sponsored, advocacy organization, created to identify and promote environmentally and economically sound markets for scrap tires. The primary goal of the Council is to assist in the creation of demand for 100 percent of the annually generated scrap tires in the United States. Based on current market demand and projected market growth, we envision the primary goal to be met by the turn of the century. A national overview of the scrap tire situation is presented, and then the situations in New York/Mid Atlantic region are discussed.

  3. Effects of highway construction on stream water quality and macroinvertebrate condition in a Mid-Atlantic Highlands watershed, USA

    USGS Publications Warehouse

    Chen, Y.; Viadero, R.C., Jr.; Wei, X.; Fortney, Ronald H.; Hedrick, Lara B.; Welsh, S.A.; Anderson, James T.; Lin, L.-S.

    2009-01-01

    Refining best management practices (BMPs) for future highway construction depends on a comprehensive understanding of environmental impacts from current construction methods. Based on a before-after-control impact (BACI) experimental design, long-term stream monitoring (1997-2006) was conducted at upstream (as control, n = 3) and downstream (as impact, n = 6) sites in the Lost River watershed of the Mid-Atlantic Highlands region, West Virginia. Monitoring data were analyzed to assess impacts of during and after highway construction on 15 water quality parameters and macroinvertebrate condition using the West Virginia stream condition index (WVSCI). Principal components analysis (PCA) identified regional primary water quality variances, and paired t tests and time series analysis detected seven highway construction-impacted water quality parameters which were mainly associated with the second principal component. In particular, impacts on turbidity, total suspended solids, and total iron during construction, impacts on chloride and sulfate during and after construction, and impacts on acidity and nitrate after construction were observed at the downstream sites. The construction had statistically significant impacts on macroinvertebrate index scores (i.e., WVSCI) after construction, but did not change the overall good biological condition. Implementing BMPs that address those construction-impacted water quality parameters can be an effective mitigation strategy for future highway construction in this highlands region. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  4. Effects of highway construction on stream water quality and macroinvertebrate condition in a mid-Atlantic highlands watershed, USA

    USGS Publications Warehouse

    Welsh, Stuart A.; Chen, Yushun; Viadero, Stuart C.; Wei, Xinchao; Hedrick, Lara B.; Anderson, James T.; Lin, Lian-Shin

    2009-01-01

    Refining best management practices (BMPs) for future highway construction depends on a comprehensive understanding of environmental impacts from current construction methods. Based on a before-after-control impact (BACI) experimental design, long-term stream monitoring (1997–2006) was conducted at upstream (as control, n = 3) and downstream (as impact, n = 6) sites in the Lost River watershed of the Mid-Atlantic Highlands region, West Virginia. Monitoring data were analyzed to assess impacts of during and after highway construction on 15 water quality parameters and macroinvertebrate condition using the West Virginia stream condition index (WVSCI). Principal components analysis (PCA) identified regional primary water quality variances, and paired t tests and time series analysis detected seven highway construction-impacted water quality parameters which were mainly associated with the second principal component. In particular, impacts on turbidity, total suspended solids, and total iron during construction, impacts on chloride and sulfate during and after construction, and impacts on acidity and nitrate after construction were observed at the downstream sites. The construction had statistically significant impacts on macroinvertebrate index scores (i.e., WVSCI) after construction, but did not change the overall good biological condition. Implementing BMPs that address those construction-impacted water quality parameters can be an effective mitigation strategy for future highway construction in this highlands region.

  5. 76 FR 11737 - Fisheries of the Northeastern United States; Monkfish; Amendment 5

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-03

    ... was generally the case with prior monkfish management actions. The trip limit model was used to assess... Management Plan (Monkfish FMP). The New England and Mid-Atlantic Fishery Management Councils (Councils... accountability measure (AM) requirements of the Magnuson-Stevens Fishery Conservation and Management...

  6. 76 FR 30265 - Fisheries of the Northeastern United States; Monkfish; Amendment 5

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-25

    ... additional Amendment 5 management measures to promote efficiency and reduce waste, brings the biological and... implements measures that were approved in Amendment 5 to the Monkfish Fishery Management Plan (FMP). The New England and Mid-Atlantic Fishery Management Councils (Councils) developed Amendment 5 to bring the...

  7. Satellite detection of phytoplankton export from the mid-Atlantic Bight during the 1979 spring bloom

    NASA Technical Reports Server (NTRS)

    Walsh, J. J.; Dieterle, D. A.; Esaias, W. E.

    1986-01-01

    Analysis of Coastal Zone Color Scanner (CZCS) imagery confirms shipboard and in situ moored fluorometer observations of resuspension of near-bottom chlorophyll within surface waters (1 to 10 m) by northwesterly wind events in the mid-Atlantic Bight. As much as 8 to 16 micrograms chl/l are found during these wind events from March to May, with a seasonal increase of algal biomass until onset of stratification of the water column. Rapid sinking or downwelling apparently occurs after subsequent wind events, however, such that the predominant surface chlorophyll pattern is approx. 0.5 to 1.5 micrograms/l over the continental shelf during most of the spring bloom. Perhaps half of the chlorophyll increase observed by satellite during a wind resuspension event represents in-situ production during the 4 to 5 day interval, with the remainder attributed to accumulation of algal biomass previously produced and temporarily stored within near-bottom water. Present calculations suggest that about 10% of the primary production of the spring bloom may be exported as ungrazed phytoplankton carbon from mid-Atlantic shelf waters to those of the continental slope.

  8. Origins of chemical pollution derived from Mid-Atlantic aircraft profiles using a clustering technique

    NASA Astrophysics Data System (ADS)

    Hains, Jennifer C.; Taubman, Brett F.; Thompson, Anne M.; Stehr, Jeffrey W.; Marufu, Lackson T.; Doddridge, Bruce G.; Dickerson, Russell R.

    Upwind sources of NO x and SO 2 play a crucial role in the amount of O 3 and aerosols in the lower troposphere in the Mid-Atlantic US. This paper describes a novel method of clustering trace gas and aerosol profiles allowing for the quantification of the relationship between point sources and pollution levels. This improves our understanding of pollution origins and has the potential for prediction of episodes of poor air quality. A hierarchical clustering method was used to classify distinct chemical and meteorological events from over 200 aircraft vertical profiles in the lower troposphere. Profile measurements included O 3, SO 2, CO and particle scattering from June to August 1997-2003, in the Mid-Atlantic US (mostly in Maryland, Pennsylvania and Virginia). The clustering technique could discriminate distinct profile shapes including measurements made during the 2002 Canadian forest fires. Forty-eight-hour back trajectories were run for each profile and the integrated NO x and SO 2 point source emissions encountered by each trajectory were calculated using data from the EPA Clean Air Market Division's emissions database. There was a strong correlation between integrated NO x emissions and O 3 profiles, indicating that O 3 profiles are strongly influenced by and can be predicted with point source emissions. There is a prevalent concentration of SO 2 over the eastern US with mixing ratios decreasing smoothly from about 3.5 ppb near the surface to 0.2 ppb at 2400 m.

  9. Vulnerability of Mid-Atlantic forested watersheds to timber harvest disturbance.

    PubMed

    Schaberg, Rex H; Abt, Robert C

    2004-06-01

    Forested watersheds of the Mid-Atlantic Region are an important economic resource. They are also critical for maintaining water quality, sustaining important ecological services, and providing habitat to many animal and plant species of conservation concern. These forests are vulnerable to disturbance and fragmentation from changing patterns of land use in the Mid-Atlantic Region, and from harvests of commercially mature and relatively inexpensive timber. The U.S. Department of Agriculture Forest Service (USDA-FS) Forest Inventory and Analysis (FIA) compiles data on forest condition by state and county. We have transformed these FIA data to a U.S. Geological Survey (USGS) 6-digithdrologic unit code (HUC 6) watershed base, and projected trends in timber growth, inventory, and harvest to 2025 using a timber economics forecasting model (SRTS). We consider forest sustainability from the perspective of timber production, and from the perspective of landscape stability important to conservation values. Simulation data is combined with FIA planted pine acreage data to form a more complete picture of forest extent, composition, and silvicultural practice. Early recognition of prevailing economic trends which encourage the fragmentation of mature forests due to increasing timber harvests may provide managers and policy makers with a planning tool to mitigate undesirable impacts. PMID:15141449

  10. Earthquake swarms on the Mid-Atlantic Ridge - Products of magmatism or extensional tectonics?

    NASA Technical Reports Server (NTRS)

    Bergman, Eric A.; Solomon, Sean C.

    1990-01-01

    The spatial and temporal patterns and other characteristics of earthquakes in 34 earthquake swarms on the Mid-Atlantic Ridge were compared with those of well-studied earthquake swarms which accompany terrestrial volcanic eruptions, to test the assumption that the teleseismically observed earthquake swarms along mid-ocean ridges are indicators of volcanism. Improved resolution of these patterns for the mid-ocean ridge events was achieved by a multiple-event relocation technique. It was found that the teleseismically located earthquake swarms on the mid-ocean ridge system have few features in common with swarms directly associated with active magmatism in terrestrial volcanic rift zones such as Hawaii and Iceland. While the possibility that some of the mid-ocean earthquake swarms might be directly associated with a current episode of eruptive activity on the Mid-Atlantic Ridge cannot be excluded, none of the 34 swarms studied in this work was found to be a conspicuously attractive candidate for such a role.

  11. Polychaete abundance, biomass and diversity patterns at the Mid-Atlantic Ridge, North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Shields, Mark A.; Blanco-Perez, Raimundo

    2013-12-01

    Recent studies have revealed that the Mid-Atlantic Ridge (MAR) in the North Atlantic Ocean accounts for a large proportion of available bathyal soft-sediment habitat. When comparing the MAR to the continental margins of the North Atlantic, it is apparent that very little is known about the soft-sediment macrofaunal community associated with the MAR. In the present study, as part of the ECOMAR (Ecosystems of the Mid-Atlantic Ridge at the Sub-Polar Front and Charlie-Gibbs Fracture Zone) project, the polychaete component of the MAR macrofaunal community was investigated. A total of 751 polychaete specimens and 133 species were identified from megacorer samples collected at four MAR sites (48-54°N, depth: 2500-2800 m) sampled during the RRS James Cook 48 cruise in the summer of 2010. Polychaetes were the most abundant member of the macrofaunal community, and there was no significant difference in polychaete abundance, biomass and diversity between any of the MAR sites. In addition, the MAR did not appear to provide a physical barrier to the distribution of bathyal polychaetes either side of the ridge.

  12. Magnetic Anomalies over the Mid-Atlantic Ridge near 27{degrees}N.

    PubMed

    Phillips, J D

    1967-08-25

    Ten magnetic profiles across the mid-Atlantic ridge near 27 degrees N show trends that are parallel to the ridge axis and symmetrical about the ridge axis. The configuration of magnetic bodies that could account for the pattern supports the Vine and Matthews hypothesis for the origin of magnetic anomalies over oceanic ridges. A polarity-reversal time scale inferred from models for sea-floor spreading in the Pacific-Antarctic ridge and radiometrically dated reversals of the geomagnetic field indicates a spreading rate of 1.25 centimeters per year during the last 6 million years and a rate of 1.65 centimeters per year between 6 and 10 million years ago. A similar analysis of more limited data over the mid-Atlantic ridge near 22 degrees N also indicates a change in the spreading rate. Here a rate of 1.4 centimeters per year appears to have been in effect during the last 5 million years; between 5 and 9 million years ago, an increased rate of 1.7 centimeters per year is indicated. The time of occurrence and relative magnitude of these changes in the spreading rate, about 5 to 6 million years ago and 18 to 27 percent, respectively, accords with the spreading rate change implied for the Juan de Fuca ridge in the northeast Pacific. PMID:17792827

  13. Mathematic model for the population biology of rabies in raccoons in the mid-Atlantic states.

    PubMed

    Coyne, M J; Smith, G; McAllister, F E

    1989-12-01

    A series of coupled differential equations was used to model the temporal dynamics of rabies in raccoons in the mid-Atlantic region of the United States. The model takes explicit account of the development of natural immunity to rabies and was used to evaluate culling and vaccination elimination strategies. For habitats typical of the mid-Atlantic states, and given the assumptions of the model, it was estimated that elimination of rabies in raccoons by culling may involve the annual removal of over 32% of the raccoon population or the yearly vaccination of up to 99% of the susceptible fraction. Assuming a constant marginal cost for both culling and vaccination, the model suggests that, whatever the actual cost of each method, the cheapest strategy will always involve either culling or vaccination alone. A combined strategy of culling and vaccination will be cheaper than culling alone only when the per capita cost of vaccination is around one-fifth or less the per capita cost of culling. PMID:2610445

  14. MEASURING BASE-FLOW CHEMISTRY AS AN INDICATOR OF REGIONAL GROUND-WATER QUALITY IN THE MID-ATLANTIC COASTAL PLAIN

    EPA Science Inventory

    Water quality in headwater (first-order) streams of the Mid-Atlantic Coastal Plain during base flow in the winter and spring is related to land use, hydrogeology, and other natural and human influences. A random survey of water quality in 174 headwater streams in the Mid-Atlantic...

  15. The influence of surface waves on water circulation in a mid-Atlantic continental shelf region

    NASA Technical Reports Server (NTRS)

    Whitlock, C. H.; Talay, T. A.

    1974-01-01

    The importance of wave-induced currents in different weather conditions and water depths (18.3 m and 36.6 m) is assessed in a mid-Atlantic continental-shelf region. A review of general circulation conditions is conducted. Factors which perturb the general circulation are examined using analytic techniques and limited experimental data. Actual wind and wave statistics for the region are examined. Relative magnitudes of the various currents are compared on a frequency of annual occurrence basis. Results indicated that wave-induced currents are often the same order of magnitude as other currents in the region and become more important at higher wind and wave conditions. Wind-wave and ocean-swell characteristics are among those parameters which must be monitored for the analytical computation of continental-shelf circulation.

  16. Past permafrost on the Mid-Atlantic coastal plain, eastern United States

    USGS Publications Warehouse

    French, H.; Demitroff, M.; Newell, W.L.

    2009-01-01

    Sand-wedge casts, soil wedges and other non-diastrophic, post-depositional sedimentary structures suggest that Late-Pleistocene permafrost and deep seasonal frost on the Mid-Atlantic Coastal Plain extended at least as far south as southern Delaware, the Eastern Shore and southern Maryland. Heterogeneous cold-climate slope deposits mantle lower valley-side slopes in central Maryland. A widespread pre-existing fragipan is congruent with the inferred palaeo-permafrost table. The high bulk density of the fragipan was probably enhanced by either thaw consolidation when icy permafrost degraded at the active layer-permafrost interface or by liquefaction and compaction when deep seasonal frost thawed. ?? 2009 John Wiley & Sons, Ltd.

  17. The stratigraphic record of recent climate change in mid-Atlantic USA

    SciTech Connect

    Brush, G.S.; Hilgartner, W.B.; Khan, H. )

    1994-06-01

    The Medieval Warm Period and Little Ice Age recorded in sediments deposited in tributaries and marshes surrounding the Chesapeake and Delaware Bays in the mid-Atlantic region of USA, by changes in pollen and seeds of terrestrial and aquatic plants, and changes in influxes of charcoal, sediment, metals and nutrients. Fossil pollen and seeds portray a regional landscape characterized by conditions drier that present from about 1000 to 1200 AD. During the same period, high charcoal and sediment influxes indicate high fire frequency. This short dry interval was followed by an expansion of submerged aquatic plants, low marsh plants, and terrestrial plants that occupy wet habitats. Charcoal influxes are extremely low during the latter interval, which extended from about 1200 AD to 1500 AD. Plant macrofossil and pollen distributions indicate a second dry period extending from 1550 to 1650 AD, which appears similar to the earlier Medieval Warm interval.

  18. Rain rate duration statistics derived from the Mid-Atlantic coast rain gauge network

    NASA Technical Reports Server (NTRS)

    Goldhirsh, Julius

    1993-01-01

    A rain gauge network comprised of 10 tipping bucket rain gauges located in the Mid-Atlantic coast of the United States has been in continuous operation since June 1, 1986. Rain rate distributions and estimated slant path fade distributions at 20 GHz and 30 GHz covering the first five year period were derived from the gauge network measurements, and these results were described by Goldhirsh. In this effort, rain rate time duration statistics are presented. The rain duration statistics are of interest for better understanding the physical nature of precipitation and to present a data base which may be used by modelers to convert to slant path fade duration statistics. Such statistics are important for better assessing optimal coding procedures over defined bandwidths.

  19. Crustal Thickness on the Mid-Atlantic Ridge: Bull's-Eye Gravity Anomalies and Focused Accretion.

    PubMed

    Tolstoy, M; Harding, A J; Orcutt, J A

    1993-10-29

    Spreading segments of the Mid-Atlantic Ridge show negative bull's-eye anomalies in the mantle Bouguer gravity field. Seismic refraction results from 33 degrees S indicate that these anomalies can be accounted for by variations in crustal thickness along a segment. The crust is thicker in the center and thinner at the end of the spreading segment, and these changes are attributable to variations in the thickness of layer 3. The results show that accretion is focused at a slow-spreading ridge, that axial valley depth reflects the thickness of the underlying crust, and that along-axis density variations should be considered in the interpretation of gravity data. PMID:17812339

  20. Carbon monoxide in the U.S. mid-Atlantic troposphere: Evidence for a decreasing trend

    NASA Astrophysics Data System (ADS)

    Hallock-Waters, Kristen A.; Doddridge, Bruce G.; Dickerson, Russell R.; Spitzer, Shane; Ray, John D.

    Nearly continuous measurements of carbon monoxide (CO) were made at Shenandoah National Park-Big Meadows in rural Virginia, a site considered representative of regional air quality, from December 1994 to November 1997. Similar observations were also made at this location from October 1988 to October 1989. These observations combine to indicate a decreasing trend in CO concentration over the U.S. mid-Atlantic region of about 5.0 ppbv yr-1, with greater than 95% confidence that the slope is significantly different from zero. The decrease suggests U.S. reductions in anthropogenic CO emissions have been effective in reducing pollutant levels. The observed trend is consistent with the U.S. EPA reported trend in emissions and the decrease in Northern Hemisphere tropospheric background CO mixing ratios observed by other researchers.

  1. PaTH: towards a learning health system in the Mid-Atlantic region

    PubMed Central

    Amin, Waqas; Tsui, Fuchiang (Rich); Borromeo, Charles; Chuang, Cynthia H; Espino, Jeremy U; Ford, Daniel; Hwang, Wenke; Kapoor, Wishwa; Lehmann, Harold; Martich, G Daniel; Morton, Sally; Paranjape, Anuradha; Shirey, William; Sorensen, Aaron; Becich, Michael J; Hess, Rachel

    2014-01-01

    The PaTH (University of Pittsburgh/UPMC, Penn State College of Medicine, Temple University Hospital, and Johns Hopkins University) clinical data research network initiative is a collaborative effort among four academic health centers in the Mid-Atlantic region. PaTH will provide robust infrastructure to conduct research, explore clinical outcomes, link with biospecimens, and improve methods for sharing and analyzing data across our diverse populations. Our disease foci are idiopathic pulmonary fibrosis, atrial fibrillation, and obesity. The four network sites have extensive experience in using data from electronic health records and have devised robust methods for patient outreach and recruitment. The network will adopt best practices by using the open-source data-sharing tool, Informatics for Integrating Biology and the Bedside (i2b2), at each site to enhance data sharing using centrally defined common data elements, and will use the Shared Health Research Information Network (SHRINE) for distributed queries across the network. PMID:24821745

  2. PaTH: towards a learning health system in the Mid-Atlantic region.

    PubMed

    Amin, Waqas; Tsui, Fuchiang Rich; Borromeo, Charles; Chuang, Cynthia H; Espino, Jeremy U; Ford, Daniel; Hwang, Wenke; Kapoor, Wishwa; Lehmann, Harold; Martich, G Daniel; Morton, Sally; Paranjape, Anuradha; Shirey, William; Sorensen, Aaron; Becich, Michael J; Hess, Rachel

    2014-01-01

    The PaTH (University of Pittsburgh/UPMC, Penn State College of Medicine, Temple University Hospital, and Johns Hopkins University) clinical data research network initiative is a collaborative effort among four academic health centers in the Mid-Atlantic region. PaTH will provide robust infrastructure to conduct research, explore clinical outcomes, link with biospecimens, and improve methods for sharing and analyzing data across our diverse populations. Our disease foci are idiopathic pulmonary fibrosis, atrial fibrillation, and obesity. The four network sites have extensive experience in using data from electronic health records and have devised robust methods for patient outreach and recruitment. The network will adopt best practices by using the open-source data-sharing tool, Informatics for Integrating Biology and the Bedside (i2b2), at each site to enhance data sharing using centrally defined common data elements, and will use the Shared Health Research Information Network (SHRINE) for distributed queries across the network. PMID:24821745

  3. Ambient light emission from hydrothermal vents on the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    White, Sheri N.; Chave, Alan D.; Reynolds, George T.; Van Dover, Cindy L.

    2002-08-01

    A spectral imaging camera was used to observe light emission from high-temperature, deep-sea vents at three hydrothermal sites on the Mid-Atlantic Ridge (MAR): Logatchev, Snake Pit, and Lucky Strike. Ambient light measured at these sites is similar to that observed at sites along the East Pacific Rise and the Juan de Fuca Ridge, with components from both thermal and non-thermal sources. The shrimp species Rimicaris exoculata, which is found on the MAR but not in the Eastern Pacific, possesses a unique photoreceptor capable of detecting low light levels. It is not yet known if R. exoculata ``sees'' vent light. However, since the characteristics of vent light appear to be unrelated to geographical location, the exclusion of R. exoculata from the Eastern Pacific is probably unrelated to differences in ambient light conditions.

  4. Carbon in Natural, Cultivated, and Restored Depressional Wetlands in the Mid-Atlantic Coastal Plain.

    PubMed

    Fenstermacher, D E; Rabenhorst, M C; Lang, M W; McCarty, G W; Needelman, B A

    2016-03-01

    Aerial extent of wetland ecosystems has decreased dramatically since precolonial times due to the conversion of these areas for human use. Wetlands provide various ecosystem services, and conservation efforts are being made to restore wetlands and their functions, including soil carbon storage. This Mid-Atlantic Regional USDA Wetland Conservation Effects Assessment Project study was conducted to evaluate the effects and effectiveness of wetland conservation practices along the Mid-Atlantic Coastal Plain. This study examined 48 wetland sites in Delaware, Maryland, Virginia, and North Carolina under natural, prior converted cropland, and 5- to 10-yr post wetland restoration states. The North Carolina sites mainly contained soils dominated by organic soil materials and therefore were analyzed separately from the rest of the sites, which primarily contained mineral soils. Soil samples were collected using the bulk density core method by horizon to a depth of 1 m and were analyzed for percent carbon. The natural wetlands were found to have significantly greater carbon stocks (21.5 ± 5.2 kg C m) than prior converted croplands (7.95 ± 1.93 kg C m; < 0.01) and restored wetlands (4.82 ± 1.13 kg C m; < 0.001). The restored and prior converted sites did not differ significantly, possibly the result of the methods used to restore the wetlands, and the relatively young age of the restored sites. Wetlands were either restored by plugging drainage structures, with minimal surface disturbance, or by scraping the surface (i.e., excavation) to increase hydroperiod. Sites restored with the scraping technique had significantly lower carbon stocks (2.70 ± 0.38 kg C m) than those restored by passive techniques (6.06 ± 1.50 kg C m; = 0.09). Therefore, techniques that involve excavation and scraping to restore hydrology appear to negatively affect C storage. PMID:27065423

  5. A Chemical Climatology of the Mid-Atlantic US Lower Troposphere: Implications for Origins and Lifetimes

    NASA Astrophysics Data System (ADS)

    Hains, J. C.; Taubman, B. F.; Thompson, A. M.; Marufu, L. T.; Stehr, J. W.; Doddridge, B. G.; Dickerson, R. R.

    2006-12-01

    Upwind sources of NOx and SO2 play a crucial role in the amount of O3 and aerosols in the lower troposphere in the Mid-Atlantic region. In this study a hierarchical clustering method was used to separate distinct chemical and meteorological events from over 200 aircraft vertical profiles in the lower troposphere measuring O3, SO2, CO, and particle absorption and scattering in the Mid-Atlantic US. Forty eight hour back trajectories were run for each profile and the integrated NOx and SO2 point source emissions encountered by each trajectory were calculated using the EPA Clean Air Market Division`s database. Greater integrated NOx emissions along back trajectories were correlated with greater O3 mixing ratios measured during the flights, indicating that O3 mixing ratios are strongly influenced by point source emissions. The amount of CO observed depended on where the profiles were made, and larger CO values were found in areas with larger mobile source emissions. Profiles with greater particle absorption were associated with greater CO values. There is a pervasive "background" SO2 profile over the eastern US with mixing ratios decreasing smoothly from about 3.5 ppb near the surface to 0.2 ppb at 2400 m altitude. The observed SO2 profile and point source emissions can be used to calculate an average SO2 lifetime. Under certain daytime summer conditions this lifetime can be less than a few hours. Profiles with larger, more scattering particles, were correlated with greater integrated SO2 emissions. The clustering technique also separated profiles made during the 2002 Canadian forest fires.

  6. Biologic Indicators of Seabed Methane Venting Along the US Mid-Atlantic Margin

    NASA Astrophysics Data System (ADS)

    Prouty, N.; Roark, E. B.; Demopoulos, A. W.; Condon, D. J.; Davis, K.; Ross, S.; Brooke, S.

    2014-12-01

    Evidence of seabed methane venting along the US Mid-Atlantic Margin is confirmed by the presence of authigenic carbonates and methantrophic deep-sea mussels, Bathymodiolus childressi, collected near areas of methane seepage. The biological indicators of methane venting presented here expand the understanding of widespread seepage identified by previous geophysical data. Both dead and living chemosynthetic mussels as well as authigenic carbonate samples were collected from Baltimore Canyon (360-430 m) and on the Virginia outer continental shelf (1600-1475 m). Stable isotope (carbon and sulfur) composition of mussel tissue material illustrates that the chemosynthetic communities are metabolically-dependent on methane rather than sulphide-oxidizing microbial symbionts. Average δ13C from tissue material was -62.80 ‰ and average δ34S was 12.58 ‰. Shell δ13C values were depleted relative to seawater dissolved inorganic carbon, highlighting the influence of methane concentration from cold seeps on shell growth. Lighter stable oxygen isotope values from shells collected at Baltimore Canyon reflect warmer temperatures relative to the colder and deeper Virginia seep site. However, at both sites isotopic disequilibrium relative to seawater δ18O suggests influence of enriched δ18O pore water. The chemical composition of the authigenic carbonates at both sites is dominated by aragonite rather than calcite, with an average δ13C signature of -46 ‰, a value expected from the microbially driven anaerobic oxidation of methane-rich fluids occurring at or near the sediment-water interface. This interpretation is supported by strontium isotope values close to modern seawater values. U/Th data are also reported from the authigenic carbonate stratigraphy to assess the timing and duration of methane venting along the US Mid-Atlantic Margin.

  7. Appendix C of the Final Report of the Mid-Atlantic Marine Wildlife Surveys, Modeling, and Data

    SciTech Connect

    2013-07-01

    The Wind Program hosted a two-day workshop on July 24-25, 2012 with scientists and regulators engaged in marine ecological survey, modeling, and database efforts pertaining to the waters of the Mid-Atlantic region. This is the third appendix to the report, the compendium of pre-workshop answers.

  8. INDICATORS OF CHANGE IN THE MID-ATLANTIC WATERSHEDS AND CONSEQUENCES OF CLIMATE IN UPPER CHESAPEAKE BAY

    EPA Science Inventory

    The rate of change in Northern Hemisphere atmospheric temperature in the past century relative to the preceding millennium strongly suggests that we are in a period of rapid global climate change. The mid-Atlantic region is quite sensitive to larger scale climate variation, which...

  9. HISTORICAL CHANGES IN GLOBAL SCALE CIRCULATION PATTERNS, MID-ATLANTIC CLIMATE STREAM FLOW AND NUTRIENT FLUXES TO THE CHESAPEAKE BAY

    EPA Science Inventory

    The rate of change in Northern Hemisphere temperature in the past century strongly suggests that we are now in a period of rapid global climate change. Also, the climate in the mid-Atlantic is quite sensitive to larger scale climate variation, which affects the frequency and seve...

  10. 78 FR 60271 - Mid-Atlantic Hydro, LLC; Notice of Preliminary Permit Application Accepted for Filing and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-01

    ..., 2013, Mid-Atlantic Hydro, LLC filed an application for a preliminary permit, pursuant to section 4(f... to the existing outlet; (2) a concrete powerhouse to be located on the right descending bank; (3) 6- megawatt (MW) and 3-MW generators for a total installed capacity of 9.0 MW; (4) a concrete tailrace...

  11. 75 FR 25291 - Outer Continental Shelf (OCS) Mid-Atlantic Proposed Oil and Gas Lease Sale 220

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-07

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR Minerals Management Service Outer Continental Shelf (OCS) Mid-Atlantic Proposed Oil and Gas Lease Sale 220... May 17, 2010 (see 75 FR 16830). Pursuant to the regulations implementing the procedural provisions...

  12. Appendix E of the Final Report of the Mid-Atlantic Marine Wildlife Surveys, Modeling, and Data

    SciTech Connect

    2013-07-01

    The Wind Program hosted a two-day workshop on July 24-25, 2012 with scientists and regulators engaged in marine ecological survey, modeling, and database efforts pertaining to the waters of the Mid-Atlantic region. This is the fifth appendix to the report, the bibliography of references.

  13. 77 FR 65380 - 2012 Fall Joint Meeting of the Ozone Transport Commission and the Mid-Atlantic Northeast...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-26

    ... AGENCY 2012 Fall Joint Meeting of the Ozone Transport Commission and the Mid-Atlantic Northeast... Environmental Protection Agency is announcing the joint 2012 Fall Meeting of the Ozone Transport Commission (OTC... inquiries contact: Ozone Transport Commission, 444 North Capitol Street NW., Suite 322, Washington, DC...

  14. INVENTORY OF ECOLOGICAL RESTORATION PROJECTS WITHIN THE MID-ATLANTIC INTEGRATED ASSESSMENT (MAIA) REGION, NATIONAL RISK MANAGEMENT RESEARCH LABORATORY

    EPA Science Inventory

    In cooperation with the Office of Water, the Office of Research and Development's National Risk Management Research Laboratory is developing an inventory of ecosystem restoration projects within the Mid-Atlantic Integrated Assessment (MAIA) Region. The MAIA Region includes five s...

  15. ROAD CLASS 3 TRANSPORTATION DIGITAL LINE GRAPHS FOR THE MID-ATLANTIC INTEGRATED ASSESSMENT (MAIA) STUDY AREA

    EPA Science Inventory

    This data set is a geographic information system (GIS) coverage of the lower level divided roads and streets (Class 3 Roads) for the United States Environmental Protection Agency (USEPA) Mid-Atlantic Integrated Assessment (MAIA) Project region. The coverage was produced using U...

  16. ROAD CLASS 5 TRANSPORTATION DIGITAL LINE GRAPHS FOR THE MID-ATLANTIC INTEGRATED ASSESSMENT (MAIA) STUDY AREA

    EPA Science Inventory

    This data set is a geographic information system (GIS) coverage of the trails, footbridges, and perimeters of parking areas (Class 5 Roads) for the United States Environmental Protection Agency (USEPA) Mid-Atlantic Integrated Assessment (MAIA) Project region. The coverage was p...

  17. ROAD CLASS 1 TRANSPORTATION DIGITAL LINE GRAPHS FOR THE MID-ATLANTIC INTEGRATED ASSESSMENT (MAIA) STUDY AREA

    EPA Science Inventory

    This data set is a geographic information system (GIS) coverage of the Interstate and United States Highways (Class 1 Roads) for the United States Environmental Protection Agency (USEPA) Mid-Atlantic Integrated Assessment (MAIA) Project region. The coverage was produced using U...

  18. ROAD CLASS 4 TRANSPORTATION DIGITAL LINE GRAPHS FOR THE MID-ATLANTIC INTEGRATED ASSESSMENT (MAIA) STUDY AREA

    EPA Science Inventory

    This data set is a geographic information system (GIS) coverage of the lower level roads and streets (Class 4 Roads) for the United States Environmental Protection Agency (USEPA) Mid-Atlantic Integrated Assessment (MAIA) Project region. The coverage was produced using US Geolog...

  19. ROAD CLASS 2 TRANSPORTATION DIGITAL LINE GRAPHS FOR THE MID-ATLANTIC INTEGRATED ASSESSMENT (MAIA) STUDY AREA

    EPA Science Inventory

    This data set is a geographic information system (GIS) coverage of the state and county highways (Class 2 Roads) for the United States Environmental Protection Agency (USEPA) Mid-Atlantic Integrated Assessment (MAIA) Project region. The coverage was produced using US Geological...

  20. COMPARING STRENGTHS OF GEOGRAPHIC AND NONGEOGRAPHIC CLASSIFICATIONS OF STREAM BENTHIC MACROINVERTEBRATES IN THE MID-ATLANTIC HIGHLANDS, USA

    EPA Science Inventory

    The US Environmental Protection Agency's (USEPA) Environmental Monitoring and Assessment Program (EMAP) sampled - 500 wadeable streams in the Mid-Atlantic Highlands region of the US during the late spring of 1993 to 1995 for a variety of physical, chemical, and biological indicat...

  1. DESIGN AND APPLICATION OF A STRATIFIED UNEQUAL-PROBABILITY STREAM SURVEY IN THE MID-ATLANTIC COASTAL PLAIN

    EPA Science Inventory

    A stratified random sample with unequal probability selection within strata was used to design a multipurpose survey of headwater watersheds in the Mid-Atlantic Coastal Plain. Objectives for data from the survey include unbiased estimates of regional headwater watershed condition...

  2. DEVELOPMENT OF A MID-ATLANTIC LAND USE/ LAND COVER CHANGE DATA SET (1970S TO 1990S)

    EPA Science Inventory

    The Mid-Atlantic region (MAIA) is comprised of southern New York, southern and western New Jersey, Pennsylvania, West Virginia, Maryland, Virginia, northeastern North Carolina, Delaware, and Washington, D.C. in the lower-48 American States. It is an ecosystem rich in streams, wet...

  3. Appendix A of the Final Report of the Mid-Atlantic Marine Wildlife Surveys, Modeling, and Data

    SciTech Connect

    2013-07-01

    The Wind Program hosted a two-day workshop on July 24-25, 2012 with scientists and regulators engaged in marine ecological survey, modeling, and database efforts pertaining to the waters of the Mid-Atlantic region. This is the first appendix to the report, the workshop agenda.

  4. LONG-TERM AGRONOMIC PERFORMANCE OF ORGANIC AND CONVENTIONAL FIELD CROPS IN THE MID-ATLANTIC REGION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Despite increasing interest in organic grain crop production among farmers, government agencies and others, there is little information on expected crop yields and production challenges in organic grain production, especially in Coastal Plain soils of the mid-Atlantic region. The USDA-ARS Beltsville...

  5. Long-term economic performance of organic and conventional field crops in the mid-Atlantic region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Interest in organic grain production is increasing in the United States but there is limited information regarding the economic performance of organic grain and forage production in the mid-Atlantic region. We present the results from enterprise budget analyses for individual crops and for complete...

  6. Persistence to Doctoral Completion of African American Men at Predominately White Universities in One Mid-Atlantic State

    ERIC Educational Resources Information Center

    Matthews, Kimberly Ann

    2012-01-01

    This qualitative study examined the experiences of 20 African American men who graduated from predominately White institutions in one mid-Atlantic state between the years of 2001 and 2011 with doctoral degrees in Education or in a Humanities and Sciences field. Interviews were conducted to gather the lived experiences of the African American men…

  7. STREAM BIOASSESSMENTS AND HOW TAXONOMIC RESOLUTION AFFECTS OUR VIEW OF THE WORLD: AN EXAMPLE FROM THE MID-ATLANTIC HIGHLANDS

    EPA Science Inventory

    During late spring 1993-1995, the USEPA's Environmental Monitoring and Assessment Program (EMAP) sampled wadeable streams in the mid-Atlantic region of the U.S. for a variety of physical, chemical, and biological indicators of environmental condition. A representative set of abou...

  8. Conservation tillage issues: cover crop-based organic rotational no-till grain production in the mid-atlantic region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic producers in the mid-Atlantic region are interested in reducing tillage, labor, and time requirements for grain production. Cover crop-based organic rotational no-till grain production is one approach to accomplishing these goals. Advancements in a system for planting crops into a mat of cov...

  9. 78 FR 69081 - Mid-Atlantic Hydro, LLC; Notice of Preliminary Permit Application Accepted for Filing and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-18

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Mid-Atlantic Hydro, LLC; Notice of Preliminary Permit Application Accepted... powerhouse, containing one 7.9-megawatt (MW) turbine generator unit; (3) a new 2.8-mile-long, 25-kilovolt...

  10. DEVELOPMENT OF A AGGREGATED INDEX OF ENVIRONMENTAL INTEGRITY FOR THE MID-ATLANTIC REGION OF THE UNITED STATES

    EPA Science Inventory

    A series of reports on the condition of resources for the Mid-Atlantic region of the United States is being produced. These reports focus on individual resources (e.g., estuaries, streams, forests, and landscapes), summarizing
    with an environmental report card for each resour...

  11. MACROINVERTEBRATE METRICS AND WATER CHEMISTRY RELATIONSHIPS FROM NON-WADEABLE STREAMS OF THE MID-ATLANTIC INTEGRITY ASSESSMENT

    EPA Science Inventory

    Macroinvertebrates were collected from non-wadeable streams during the summer of 1997 and 1998 for the USEPA Environmental Monitoring and Assessent Program (EMAP) Mid-Atlantic Integrated Assessment (MAIA). In this study we examined macroinvertebrate metrics to identify those whi...

  12. THE RELATIONSHIP BETWEEN STREAM CHEMISTRY AND WATERSHED LAND COVER DATA IN THE MID-ATLANTIC REGION, U.S.

    EPA Science Inventory

    In order to investigate the relationship between stream chemistry and watershed land cover at the regional scale, we analyzed data from 368 wadeable streams sampled in the mid-Atlantic region of the U.S. during spring 1993-1994. Study sites were selected using a probability sampl...

  13. EFFECTS OF ACIDIC DEPOSITION ON STREAMS IN THE APPALACHIAN MOUNTAINS AND PIEDMONT REGION OF THE MID-ATLANTIC UNITED STATES

    EPA Science Inventory

    Streams in the Appalachian Mountain area of the Mid-Atlantic receive some of the largest acidic deposition loadings of any region of the United States. ompilation of survey data from the Mid-Appalachians yields a consistent picture of the acid-base status of streams. cidic stream...

  14. Sisterhood Surveyed. Proceedings of the Mid-Atlantic Women's Studies Association Conference (West Chester, Pennsylvania, October 1-2, 1982).

    ERIC Educational Resources Information Center

    Sessa, Anne Dzamba, Ed.

    Proceedings of the 1982 conference of the Mid-Atlantic Women's Studies Association are presented. Synopses of sessions include the following topics: iconography of sisterhood, matriarchy, ethnic and cultural critiques, political perspectives, and nontraditional women students. Conference papers and authors are as follows: "Friends for Half a…

  15. LONG-TERM AGRONOMIC PERFORMANCE OF ORGANIC AND CONVENTIONAL FIELD CROPS IN THE MID-ATLANTIC REGION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Despite increasing interest in organic grain crop production among farmers, government agencies and other stakeholders, there is little information on expected crop yields and production challenges in organic grain production, especially in Coastal Plain soils of the mid-Atlantic region. The USDA-AR...

  16. The Predictive Validity of Selected Benchmark Assessments Used in the Mid-Atlantic Region. Issues & Answers. REL 2007-No. 017

    ERIC Educational Resources Information Center

    Brown, Richard S.; Coughlin, Ed

    2007-01-01

    This report examines the availability and quality of predictive validity data for a selection of benchmark assessments identified by state and district personnel as in use within Mid-Atlantic Region jurisdictions. Based on a review of practices within the school districts in the region, this report details the benchmark assessments being used, in…

  17. Bathypelagic Food Web Structure of the Northern Atlantic Mid-Atlantic Ridge Based on Stable Isotope Analysis

    EPA Science Inventory

    The objective of our study was to characterize the trophic connections of the dominant fishes of the deep-pelagic region of the northern Mid-Atlantic Ridge (MAR) with respect to vertical distribution using carbon (C) and nitrogen (N) stable isotope analysis. Our goals were to id...

  18. DETERMINING BACKGROUND EXPOSURE TO PETROLEUM AND COMBUSTION BY-PRODUCTS: COMPARISON OF MID-WESTERN AND MID-ATLANTIC REGIONS

    EPA Science Inventory

    Regional background levels of exposure to fish from petroleum and combustion by-products were determined for the state of Ohio and the mid-Atlantic region. Exposures were measured using bile metabolites that fluoresce at 290/335 nm for naphthalene(NAPH)-type compounds and at 380...

  19. COMPARISON OF MID-WESTERN AND MID-ATLANTIC REGIONS EXPOSURE CRITERIA FOR PETROLEUM AND COMBUSTION BY-PRODUCTS

    EPA Science Inventory

    Regional background levels of exposure to fish from petroleum and combustion by-products were determined for the state of Ohio (mid-Western) and the mid-Atlantic region. Exposures were measured using bile metabolites that fluoresce at 290/335 nm for naphthalene (NAPH)-type compou...

  20. CONTAMINATION OF FISH IN STREAMS OF THE MID-ATLANTIC REGION: AN APPROACH TO REGIONAL INDICATOR SELECTION AND WILDLIFE ASSESSMENT

    EPA Science Inventory

    The extent of contamination of fish in the Mid-Atlantic Region was evaluated as part of the U.S. Environmental Protection Agency's Monitoring and Assessment Program's regional assessment in 1993 through 1994. Fish assemblages from wadeable streams were dominated by small, short-...

  1. Feeding ecology of the Stomiiformes (Pisces) of the northern Mid-Atlantic Ridge. 1. The Sternoptychidae and Phosichthyidae

    NASA Astrophysics Data System (ADS)

    Carmo, Vanda; Sutton, Tracey; Menezes, Gui; Falkenhaug, Tone; Bergstad, Odd Aksel

    2015-01-01

    Comprehensive trophic studies in the vast mid-oceanic regions are rare compared to coastal and fisheries-oriented investigations. Field sampling conducted by the multidisciplinary, international Census of Marine Life project MAR-ECO, namely the 2004 G.O. Sars cruise, has generated one of the largest open ocean deep-pelagic sample collections ever obtained. With the overall goal of understanding carbon flow processes within and through the deep-pelagic nekton associated with the northern Mid-Atlantic Ridge system (N MAR), quantitative trophic analyses were conducted in order to identify the major intraspecific patterns in diet of characteristic members of the midwater fish community. Diets of five abundant species of zooplanktivorous fishes were examined in detail in terms of prey taxonomy and variability in space, ontogeny and diel cycle. Two major patterns of feeding were identified. Pattern 1 included three species preying primarily on copepods, Argyropelecus hemigymnus, Maurolicus muelleri and Vinciguerria attenuata, the former two of which revealed spatial differences in diet with latitude, mostly likely related to latitudinal prey distributions and densities. Maurolicus demonstrated ecological differences in diet that mirrored phenotypic variation North and South of the Subpolar Front, an 'oceanic species concept' question that warrants further research. Pattern 2 included two species feeding primarily on amphipods, Argyropelecus aculeatus and Sternoptyx diaphana, both of which showed ontogenetic variability in feeding primarily related to specific amphipod taxon sizes, rather than prey switching to other major prey taxa. This is the first study that highlights the importance of amphipods in the diets of these species. All fish species showed selectivity in prey choice, possibly related to competition with the other major nekton components along the N MAR, namely the Myctophidae and other zooplanktivorous Stomiiformes. Daily ration fell within the expected

  2. Mid- Atlantic Gas Hydrate, Heat Flow, and Basin Analysis: Implications to Hydrocarbon Production in the Carolina Trough

    NASA Astrophysics Data System (ADS)

    Phrampus, B. J.

    2015-12-01

    The new Mid- and South Atlantic Planning Areas for oil and gas leasing is proposed to open in 2021. This region lacks in contemporary geologic and geophysical petroleum data and has no conventional wells drilled within the proposed leasing area. As such, addressing the hydrocarbon potential of this region is particularly difficult. Here, we use new and legacy multi-channel seismic data with heat flow observations, ocean temperature measurements, and new seismic interpretations of gas hydrate deposits to determine basin-wide heat flow along the Mid- Atlantic. These data reveal a conductive heat flow regime along the continental margin with a lack of fluid flow that is consistent with sea floor spreading rates and cooling oceanic crust. We then use these observations in combination with basal heat flow models and sedimentation records to determine the thermal history of a cross section of the Carolina Trough. These models reveal varying depth of potential hydrocarbon production that begin at ~ 2000 mbsf and extend down to depths greater than 7000 mbsf across the Carolina Trough. These potentially productive depths correspond to varying stratal ages, but all models contain the Late Jurassic, which is a potential analog to the U.S. Gulf Coast's Smackover Formation. Additionally, the timing of hydrocarbon generation reveal that Early through Middle Jurassic evaporite deposits and Late Jurassic tight limestones should have been in place before the Early Jurassic source rocks reached a depth of burial sufficiently deep for the production of hydrocarbons. These potential seals may trap significant quantities of hydrocarbons with in the Jurassic layers, resulting in significant hydrocarbon potential within the Carolina Trough.

  3. The formation and linking of mid-segment detachment faults at the slow-spreading Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Schouten, H.; Smith, D. K.; Dick, H. J.; Escartin, J.

    2011-12-01

    The Mid-Atlantic Ridge axis at 16.5N has a remarkably high rate of teleseismic and hydrophone-recorded seismicity, and we have identified it as a region of active detachment faulting. Limited multibeam bathymetry data on the west side of the median valley show two parallel, linear ridges: 50-km-long West Ridge at 15 km west of the volcanic axis, and 10-km-long East Ridge at only 6 km from the axis. The ridges are interpreted to be the tops of rotated detachment fault scarps (breakaways), indicating significant fault rotation (> 25 degrees). A striated surface, characteristic of a core complex, is associated with West Ridge. This region stands out because it presents a dramatic demonstration of a new detachment fault forming nearer to the axis (East Ridge) and interrupting the overall development of what we interpret to be a longer, older and still active detachment fault that has its breakaway at the older West Ridge. We hypothesize that the section of the West Ridge detachment behind the East Ridge detachment was deactivated when East Ridge formed and furthermore, that the East Ridge detachment has linked into the West Ridge detachment to form a single detachment fault. This area represents an opportunity to address the initiation and cessation of mid-segment detachment faulting as well as how the faults link along the axis. Sampling of the detachment footwall will allow us to relate the subcrustal architecture of the segment to the local magmatic budget, and how this influences the initiation and geometry of the faulting. A broad, well-developed neovolcanic zone at the adjacent spreading axis suggests abundant volcanism. The greater depth of the local off-axis morphology, though, indicates that East Ridge may have formed in a relatively amagmatic corridor. Massifs at the western limit of the multibeam bathymetry data suggest asymmetric spreading through detachment faulting has dominated this region for at least the last several million years and perhaps much

  4. Longer and More Frequent Mid-Atlantic Heat Waves by Mid-Century

    NASA Astrophysics Data System (ADS)

    Sewall, J. O.

    2011-12-01

    Changes in extreme weather events are an area of concern in the face of changing climate. Heat waves (periods of sustained, above normal temperature) are of particular interest given the heavy costs, not only in strain on infrastructure and utilities but also in loss of human life, they can engender (e.g. in the United States, 1995, 2001, 2010; in Europe, 2003, 2006, 2010). In many instances, the costs of heat waves are associated with insufficient local preparedness and infrastructure. With the Earth predicted to warm, future heat waves could be more frequent, sustained, or intense; therefore, preparation for such events might greatly reduce their societal impacts. This study focuses on potential heat wave changes in the highly populous (greater than 96 people/km2) mid-Atlantic region of the Eastern United States from Alexandria, VA through Washington, DC, Baltimore, MD, Philadelphia, PA, the entire state of New Jersey, New York, NY, Long Island, NY, and the entire state of Connecticut. A nested regional climate model (RegCM3) simulated future climate over this region at a 10 km horizontal resolution for two future emissions scenarios (SRES B1 and A1FI). Output from the NCAR CCSM3 drove the regional simulations for two fifteen-year windows from 2050 - 2064 and 2085 - 2099. The final decade of each simulation was averaged for analyses and compared to a 1990 - 1999 simulation. Under both future forcing scenarios, heat waves in the study region increase compared to the twentieth century. In the B1 simulation, the number of summer (June, July, and August average) days exceeding 37.8° C increased by up to 600% at mid-century and up to 200% at the end of the century; the duration of the longest summer heat wave (consecutive days exceeding 37.8° C) increased by up to 26 days at mid-century and up to 10 days by the end of the century. For the A1FI scenario, the number of summer days exceeding 37.8° C increased by up to 250% at mid-century and up to 1300% at the end of

  5. New High-Resolution Mapping of Submarine Canyons in the Mid-Atlantic Continental Margin

    NASA Astrophysics Data System (ADS)

    ten Brink, U. S.; Chaytor, J. D.; Brothers, D. S.; Twichell, D. C.; Ross, S. W.; Brooke, S.

    2011-12-01

    During June 2011, a BOEMRE/NOAA/USGS -funded multibeam bathymetry survey mapped the upper reaches (<900-m depths) of the Norfolk, Washington, and Baltimore canyons. Combined with existing multibeam bathymetry of the continental slope and rise, the new data provide a detailed view of the sedimentary processes that shaped the mid-Atlantic margin. The shelf-breaching canyon heads are surrounded by two terraces at depths of 95-100 m and 115-125 m in the Norfolk and Washington canyons and at depths of 115-125 m and 135-145 m in the Baltimore canyon. These terraces may represent paleo-shorelines formed during sea level stillstands. The canyon thalwegs within the shelf appear to be filled with sand in accord with old core results. The gradient of their thalweg profile is variable and relatively low across the shelf, slope, and upper rise, in contrast to the concave gradient of most non-shelf breaching canyons in the region. A few of the non-shelf breaching canyons in the mid-Atlantic margin also have relatively low and variable gradients suggesting that they once breached the shelf but are now completely filled. The seaward extensions of the Norfolk, Washington, and Baltimore canyons onto the continental rise are characterized by channels bordered by 100-200 m high levees. In places, these channels meander tightly. The extensions of other canyons onto the rise are either defined by subtle, linear depressions or cannot be traced. Channel-capture by adjacent canyons and channel abandonment originate in the lower slope and were prompted by either landslides or levee breaching. These observations indicate dynamic outer shelf deltas fed by large rivers, which were active at the last glacial maximum (LGM). The river channels on the shelf have been progressively filled during the Holocene. The clear expression of levied channels on the continental rise that extend from shelf-breaching canyons suggests that these canyons were the last ones to deliver turbidity flows to the rise

  6. Geological mapping of the Rainbow Massif, Mid-Atlantic Ridge, 36°14'N

    NASA Astrophysics Data System (ADS)

    Ildefonse, B.; Fouquet, Y.; Hoisé, E.; Dyment, J.; Gente, P.; Thibaud, R.; Bissessur, D.; Yatheesh, V.; Momardream 2008 Scientific Party*, T.

    2008-12-01

    The Rainbow hydrothermal field at 36°14'N on the Mid-Atlantic Ridge is one of the few known sites hosted in ultramafic basement. The Rainbow Massif is located along the non-transform offset between the AMAR and South AMAR second-order ridge segments, and presents the characteristic dome morphology of oceanic core complexes, although no corrugated surface has been observed so far. One of the objectives of Cruises MOMAR DREAM (July 2007, R/V Pourquoi Pas ?; Aug-Sept 2008, R/V Atalante) was to study the petrological and structural context of the hydrothermal system at the scale of the Rainbow Massif. Our geological sampling complements previous ones achieved during Cruises FLORES (1997) and IRIS (2001), and consisted in dredge hauls, and submersible dives by manned submersible Nautile and ROV Victor. The tectonics of the Rainbow Massif is dominated by a N-S trending fault pattern on the western flank of the massif, and a series of SW-NW ridges on its northeastern side. The active hydrothermal site is located in the area were these two systems crosscut. The most abundant recovered rock type is peridotite (harzburgite and dunite) that presents a variety of serpentinization styles and intensity, and a variety of deformation styles (commonly undeformed, sometimes displaying ductile or brittle foliations). Serpentinites are frequently oxidized. Some peridotite samples have melt impregnation textures. Massive chromitite was recovered in one dredge haul. Variously evolved gabbroic rocks were collected as discrete samples or as centimeter to decimeter-thick dikes in peridotites. Basalts and fresh basaltic glass were also sampled in talus and sediments on the southwestern and northeastern flanks of the massif. Our sampling is consistent with the lithological variability encountered in oceanic core complexes along the Mid-Atlantic Ridge and Southwest Indian Ridge. The stockwork of the hydrothermal system has been sampled on the western side of the present-day hydrothermal

  7. Metal Concentrations in Two Commercial Tuna Species from an Active Volcanic Region in the Mid-Atlantic Ocean.

    PubMed

    Torres, Paulo; Rodrigues, Armindo; Soares, Lília; Garcia, Patrícia

    2016-02-01

    Concentrations of cadmium (Cd), mercury (Hg), and lead [Pb (µg g(-1) wet weight)] were determined in liver and muscle samples of 15 bigeye (Thunnus obesus) and 15 skipjack tunas (Katsuwonus pelamis) caught over an active volcanic region in the Mid-Atlantic Ocean (Azores, Portugal) and evaluated regarding consumption safety. None of the muscle samples (edible part) exceeded the European Union (EU) maximum limits (MLs) for Hg and Pb. Cd concentrations in muscle were much greater than EU MLs with 53 and 26 % of the bigeye tuna and skipjack tuna, respectively, in exceedance of the limits. Results obtained in this work, together with other studies in the same region, support the existence of an important volcanic source of Cd in waters of the Mid-Atlantic region, which should be carefully monitored given the importance of many commercial marine species for human consumption, mainly in Europe. PMID:26681184

  8. Wildlife Densities and Habitat Use Across Temporal and Spatial Scales on the Mid-Atlantic Outer Continental Shelf. Final Report to the Department of Energy EERE Wind & Water Power Technologies Office

    SciTech Connect

    Williams, Kathryn A.; Stenhouse, Iain J.; Johnson, Sarah M.; Connelly, Emily E.

    2015-10-01

    The Mid-Atlantic Baseline Studies Project helped address environmental barriers to offshore wind energy development in the mid-Atlantic region by providing regulators, developers, and other stakeholders with comprehensive baseline ecological data and analyses. Project funders and collaborators from a range of academic institutions, non-governmental organizations, federal agencies, foundations, and private companies came together to study bird, sea turtle, and marine mammal distributions, densities, and movements on the mid-Atlantic Outer Continental Shelf between 2012 and 2014. Specific project activities and goals included the following: (1) Conduct standardized surveys to quantify bird, sea turtle, and marine mammal densities seasonally and annually throughout the study region and identify important habitat use or aggregation areas. (2) Develop statistical models to help understand the drivers of wildlife distribution and abundance patterns. (3) Use individual tracking data for several focal bird species to provide information on population connectivity and individual movements that is complementary to survey data. (4) Identify species that are likely to be exposed to offshore wind energy development activities in the mid-Atlantic study area. (5) Develop U.S.-based technological resources and assessment methods for future monitoring efforts, including a comparison of high resolution digital video aerial surveys to boat-based surveys. (6) Help meet data needs associated with National Environmental Policy Act (NEPA), Marine Mammal Protection Act, and Endangered Species Act requirements, by contributing several years of data and analysis towards future Environmental Impact Statements. This report consists of six parts: Project overview (executive summary and Chapters 1-2); Examining wildlife distributions and relative abundance from a digital video aerial survey platform (Chapters 3-6); Examining wildlife distributions and abundance using boat-based surveys

  9. Delta-proteobacterial SAR324 group in hydrothermal plumes on the South Mid-Atlantic Ridge.

    PubMed

    Cao, Huiluo; Dong, Chunming; Bougouffa, Salim; Li, Jiangtao; Zhang, Weipeng; Shao, Zongze; Bajic, Vladimir B; Qian, Pei-Yuan

    2016-01-01

    In the dark ocean, the SAR324 group of Delta-proteobacteria has been associated with a chemolithotrophic lifestyle. However, their electron transport chain for energy generation and information system has not yet been well characterized. In the present study, four SAR324 draft genomes were extracted from metagenomes sampled from hydrothermal plumes in the South Mid-Atlantic Ridge. We describe novel electron transport chain components in the SAR324 group, particularly the alternative complex III, which is involved in energy generation. Moreover, we propose that the C-type cytochrome, for example the C553, may play a novel role in electron transfer, adding to our knowledge regarding the energy generation process in the SAR324 cluster. The central carbon metabolism in the described SAR324 genomes exhibits several new features other than methanotrophy e.g. aromatic compound degradation. This suggests that methane oxidation may not be the main central carbon metabolism component in SAR324 cluster bacteria. The reductive acetyl-CoA pathway may potentially be essential in carbon fixation due to the absence of components from the Calvin-Benson cycle. Our study provides insight into the role of recombination events in shaping the genome of the SAR324 group based on a larger number of repeat regions observed, which has been overlooked thus far. PMID:26953077

  10. Aerobic Anoxygenic Phototrophic Bacteria in the Mid-Atlantic Bight and the North Pacific Gyre

    PubMed Central

    Cottrell, Matthew T.; Mannino, Antonio; Kirchman, David L.

    2006-01-01

    The abundance of aerobic anoxygenic phototrophic (AAP) bacteria, cyanobacteria, and heterotrophs was examined in the Mid-Atlantic Bight and the central North Pacific Gyre using infrared fluorescence microscopy coupled with image analysis and flow cytometry. AAP bacteria comprised 5% to 16% of total prokaryotes in the Atlantic Ocean but only 5% or less in the Pacific Ocean. In the Atlantic, AAP bacterial abundance was as much as 2-fold higher than that of Prochlorococcus spp. and 10-fold higher than that of Synechococcus spp. In contrast, Prochlorococcus spp. outnumbered AAP bacteria 5- to 50-fold in the Pacific. In both oceans, subsurface abundance maxima occurred within the photic zone, and AAP bacteria were least abundant below the 1% light depth. The abundance of AAP bacteria rivaled some groups of strictly heterotrophic bacteria and was often higher than the abundance of known AAP bacterial genera (Erythrobacter and Roseobacter spp.). Concentrations of bacteriochlorophyll a (BChl a) were low (∼1%) compared to those of chlorophyll a in the North Atlantic. Although the BChl a content of AAP bacteria per cell was typically 20- to 250-fold lower than the divinyl-chlorophyll a content of Prochlorococcus, the pigment content of AAP bacteria approached that of Prochlorococcus in shelf break water. Our results suggest that AAP bacteria can be quite abundant in some oceanic regimes and that their distribution in the water column is consistent with phototrophy. PMID:16391092

  11. Trace Gases and Aerosol Optical Properties Over the US Mid-Atlantic During Summer 2001

    NASA Astrophysics Data System (ADS)

    Doddridge, B. G.; Piety, C. A.

    2001-12-01

    Anthropogenic emissions from rapid urban sprawl, commuter/commercial traffic and industrialization along the East Coast of the United States have a profound effect on urban and regional air quality. During summer 2001 we used a light aircraft research platform operated from North Carolina northward through Pennsylvania measuring meteorological scalars, selected trace gases and aerosol optical properties on selected pollution episode days. The goal of this research is to gain an improved understanding of the sources, sinks, transport and photochemical transformations controlling the observed abundance of photochemical oxidants and fine particulate haze over the U.S. Mid-Atlantic region. The aircraft research capabilities will be described, over 60 research flights totaling in excess of 160 flight hours summarized, and key findings presented. Although westerly transport of remnant ozone and haze along with precursors can make substantial contributions to observed urban corridor air quality aloft, significant production downwind of the urban center often can occur within the planetary boundary layer during the afternoon hours.

  12. Aerobic Anoxygenic Phototrophic Bacteria in the Mid-Atlantic Bight and the North Pacific Gyre. Revised

    NASA Technical Reports Server (NTRS)

    Cottrell, Matthew T.; Mannino, Antonio; Kirchman, David L.

    2005-01-01

    The abundance of aerobic anoxygenic phototrophic (AM) bacteria, cyanobacteria and heterotrophs was examined in the Mid-Atlantic Bight and the central North Pacific gyre using infrared fluorescence microscopy coupled with image analysis and flow cytometry. AAP bacteria comprised 5% to 16% of total prokaryotes in the Atlantic but only 5% or less in the Pacific. In the Atlantic, AAP bacterial abundance was as much as 2-fold higher than Prochlorococcus and 10-folder higher than Synechococcus. In contrast, Prochlorococcus outnumbered AAP bacteria 5- to 50-fold in the Pacific. In both oceans, subsurface abundance maxima occurred within the photic zone, and AAP bacteria were least abundant below the 1% light depth. Concentrations of bacteriochlorophyll a (BChl a) were low (approx.1%) compared to chlorophyll a. Although the BChl a content of AAP bacteria per cell was typically 20- to 250-fold lower than the divinyl-chlorophyll a content of Prochlorococcus, in shelf break water the pigment content of AAP bacteria approached that of Prochlorococcus. The abundance of AAP bacteria rivaled some groups of strictly heterotrophic bacteria and was often higher than the abundance of known AAP genera (Erythrobacter and Roseobacter spp.). The distribution of AAP bacteria in the water column, which was similar in the Atlantic and the Pacific, was consistent with phototrophy.

  13. Documenting nursing and health care history in the mid-Atlantic region.

    PubMed

    Weinberg, D M

    1993-01-01

    The records of health care institutions can be of great value to library patrons. Yet, librarians rarely provide these unique resources because records must be collected, arranged, and described before they can be useful to patrons. The University of Pennsylvania's Center for the Study of the History of Nursing conducted a survey of health care agencies in the mid-Atlantic region to locate records created by area health care institutions. The goals of this project were to develop a database of primary source materials, to place organizational records with enduring value at suitable repositories, and to assist in the development of in-house archival programs at agencies keeping records. In-house programs provide health care institutions with a systematic way to preserve their records for administrative, legal, fiscal, and research use. Such programs also facilitate access to information, reduce cost through records management, and promote an institution through preservation and use of its historical records. The survey demonstrated that record keeping is not coordinated in most institutions, and that institutional awareness of the organization or content of records is minimal. PMID:8428186

  14. Application of a multipurpose unequal probability stream survey in the Mid-Atlantic Coastal Plain

    USGS Publications Warehouse

    Ator, S.W.; Olsen, A.R.; Pitchford, A.M.; Denver, J.M.

    2003-01-01

    A stratified, spatially balanced sample with unequal probability selection was used to design a multipurpose survey of headwater streams in the Mid-Atlantic Coastal Plain. Objectives for the survey include unbiased estimates of regional stream conditions, and adequate coverage of unusual but significant environmental settings to support empirical modeling of the factors affecting those conditions. The design and field application of the survey are discussed in light of these multiple objectives. A probability (random) sample of 175 first-order nontidal streams was selected for synoptic sampling of water chemistry and benthic and riparian ecology during late winter and spring 2000. Twenty-five streams were selected within each of seven hydrogeologic subregions (strata) that were delineated on the basis of physiography and surficial geology. In each subregion, unequal inclusion probabilities were used to provide an approximately even distribution of streams along a gradient of forested to developed (agricultural or urban) land in the contributing watershed. Alternate streams were also selected. Alternates were included in groups of five in each subregion when field reconnaissance demonstrated that primary streams were inaccessible or otherwise unusable. Despite the rejection and replacement of a considerable number of primary streams during reconnaissance (up to 40 percent in one subregion), the desired land use distribution was maintained within each hydrogeologic subregion without sacrificing the probabilistic design.

  15. Seaweed biogeography of the mid-Atlantic coast of the United States

    NASA Astrophysics Data System (ADS)

    Searles, R. B.

    1984-06-01

    The northern boundary of the warm temperate region of the mid-Atlantic coast of the United States is set at Cape Hatteras; the southern boundary lies at Cape Canaveral. There is some spillover of cool temperate species south of Cape Hatteras into North Carolina and spillover of warm temperate species south of Cape Canaveral toward Palm Beach. Elements of the warm temperate flora also extend into the northern Gulf of Mexico, but precise limits to the flora cannot be drawn there. Thirty-one species are endemic to the warm temperate flora. The inshore waters of North Carolina include approximately equal numbers of species with northern and southern centres of distribution; the species of the offshore waters have predominantly southern affinities, but also include most of the endemic species. Seasonal changes in the shallow water flora of North Carolina reflect eurythermal cool temperate and tropical elements in winter and summer respectively and a year-round warm temperate element. These groupings have been verified by experimental studies in which light and temperature were varied. The deep water flora is a summer flora dominated by perennial species. The inshore, eurythermal cool temperate and tropical species have a variety of cryptic stages by which they persist throughout the year.

  16. Myctophid feeding ecology and carbon transport along the northern Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Hudson, Jeanna M.; Steinberg, Deborah K.; Sutton, Tracey T.; Graves, John E.; Latour, Robert J.

    2014-11-01

    Myctophids are among the most abundant fishes in the world's ocean and occupy a key position in marine pelagic food webs. Through their significant diel vertical migrations and metabolism they also have the potential to be a significant contributor to carbon export. We investigated the feeding ecology and contribution to organic carbon export by three myctophid species, Benthosema glaciale, Protomyctophum arcticum, and Hygophum hygomii, from a structurally and ecologically unique ecosystem- the Mid-Atlantic Ridge (MAR). Similar to the results of previous studies, the diet of these fishes was primarily copepods and euphausiids, however, gelatinous zooplankton was identified in the diet of B. glaciale for the first time. Ridge section and time of day were significant explanatory variables in the diet of B. glaciale as determined by canonical correspondence analysis, while depth was the only significant explanatory variable in the diet of P. arcticum. Daily consumption by MAR myctophids was less than 1% of dry body weight per day and resulted in the removal of less than 1% of zooplankton biomass daily. Although lower than previous estimates of carbon transport by myctophids and zooplankton in other areas, MAR myctophid active transport by diel vertical migration was equivalent to up to 8% of sinking particulate organic carbon in the North Atlantic. While highly abundant, myctophids do not impart significant predation pressure on MAR zooplankton, and play a modest role in the active transport of carbon from surface waters.

  17. Discovery of a magma chamber and faults beneath a Mid-Atlantic Ridge hydrothermal field.

    PubMed

    Singh, Satish C; Crawford, Wayne C; Carton, Hélène; Seher, Tim; Combier, Violaine; Cannat, Mathilde; Pablo Canales, Juan; Düsünür, Doga; Escartin, Javier; Miranda, J Miguel

    2006-08-31

    Crust at slow-spreading ridges is formed by a combination of magmatic and tectonic processes, with magmatic accretion possibly involving short-lived crustal magma chambers. The reflections of seismic waves from crustal magma chambers have been observed beneath intermediate and fast-spreading centres, but it has been difficult to image such magma chambers beneath slow-spreading centres, owing to rough seafloor topography and associated seafloor scattering. In the absence of any images of magma chambers or of subsurface near-axis faults, it has been difficult to characterize the interplay of magmatic and tectonic processes in crustal accretion and hydrothermal circulation at slow-spreading ridges. Here we report the presence of a crustal magma chamber beneath the slow-spreading Lucky Strike segment of the Mid-Atlantic Ridge. The reflection from the top of the magma chamber, centred beneath the Lucky Strike volcano and hydrothermal field, is approximately 3 km beneath the sea floor, 3-4 km wide and extends up to 7 km along-axis. We suggest that this magma chamber provides the heat for the active hydrothermal vent field above it. We also observe axial valley bounding faults that seem to penetrate down to the magma chamber depth as well as a set of inward-dipping faults cutting through the volcanic edifice, suggesting continuous interactions between tectonic and magmatic processes. PMID:16943836

  18. Imprint of Late Quaternary Climate Change on the Mid-Atlantic Landscape

    NASA Astrophysics Data System (ADS)

    Pavich, M.; Markewich, H.; Newell, W. L.; Litwin, R.; Smoot, J.; Brook, G.

    2009-12-01

    Recent geomorphic, lithostratigraphic, palynologic and chronostratigraphic investigations of the mid-Atlantic region show that much of the modern landscape flanking the Chesapeake Bay and the Potomac River is developed on late Quaternary sediments. These deposits, dated by OSL and 14C, include transgressive marine and estuarine sediments deposited between 120ka and 32ka, and parabolic dunes formed between 32ka and 15ka. The stacked estuarine units were deposited in a subsiding basin as eustatic sea level fell from +7m to -60m. The estuarine units contain pollen that provides evidence for millennial scale climate fluctuations. The dunes formed during the period of rapid expansion of the Laurentide Ice Sheet as sea level fell to -120m. Permafrost features such as frost wedges and periglacial “pots” formed during cold intervals associated with marine oxygen isotope stages 4 and 2. This periglacial climate, along with glacioisostatic adjustments to growth and decay of the Laurentide Ice Sheet, affected landscape processes at least as far south as the Potomac River valley. While many of these features were recognized in earlier mapping and stratigraphic investigations, OSL dating has greatly extended the range of available dates and significantly improved our understanding of the impacts of highly variable periglacial climate on this region.

  19. Clean Coal Technology: Region 3 Market Description, Mid-Atlantic. Summary

    SciTech Connect

    Not Available

    1993-09-01

    The Region 3 Market Description summary provides information that can be used in developing an understanding of the potential markets for clean coal technologies (CCTs) in the Mid-Atlantic Region. This region (which geographically is Federal Region 3) consists of the District of Columbia and the following five states: Delaware, Virginia, Maryland, West Virginia, Pennsylvania. In order to understand the potential market, a description is provided of the region`s energy use, power generation capacity, and potential growth. Highlights of state government activities that could have a bearing on commercial deployment of CCTs are also presented. The potential markets characterized in this summary center on electric power generation by investor-owned, cooperative, and municipal electric utilities and involve planned new capacity additions and actions taken by utilities to comply with Phases I and II of the Clean Air Act Amendments (CAAA) of 1990. Regulations, policies, utility business strategies, and organizational changes that could impact the role of CCTs as a utility option are identified and discussed. The information used to develop the Region 3 Market Description is based mainly on an extensive review of plans and annual reports of 17 investor-owned, cooperative, and municipal electric utilities and public information on strategies and actions for complying with the CAAA of 1990.

  20. Karst of the Mid-Atlantic region in Maryland, West Virginia, and Virginia

    USGS Publications Warehouse

    Doctor, Daniel H.; Weary, David J.; Brezinski, David K.; Orndorff, Randall C.; Spangler, Lawrence E.

    2015-01-01

    The Mid-Atlantic region hosts some of the most mature karst landscapes in North America, developed in highly deformed rocks within the Piedmont and Valley and Ridge physiographic provinces. This guide describes a three-day excursion to examine karst development in various carbonate rocks by following Interstate 70 west from Baltimore across the eastern Piedmont, across the Frederick Valley, and into the Great Valley proper. The localities were chosen in order to examine the structural and lithological controls on karst feature development in marble, limestone, and dolostone rocks with an eye toward the implications for ancient landscape evolution, as well as for modern subsidence hazards. A number of caves will be visited, including two commercial caverns that reveal strikingly different histories of speleogenesis. Links between karst landscape development, hydrologic dynamics, and water resource sustainability will also be emphasized through visits to locally important springs. Recent work on quantitative dye tracing, spring water geochemistry, and groundwater modeling reveal the interaction between shallow and deep circulation of groundwater that has given rise to the modern karst landscape. Geologic and karst feature mapping conducted with the benefit of lidar data help reveal the strong bedrock structural controls on karst feature development, and illustrate the utility of geologic maps for assessment of sinkhole susceptibility.

  1. Arsenic speciation in food chains from mid-Atlantic hydrothermal vents

    USGS Publications Warehouse

    Taylor, Vivien F.; Jackson, Brian P.; Siegfried, Matthew R.; Navratilova, Jana; Francesconi, Kevin A.; Kirshtein, Julie; Voytek, Mary

    2012-01-01

    Arsenic concentration and speciation were determined in benthic fauna collected from the Mid-Atlantic Ridge hydrothermal vents. The shrimp species, Rimicaris exoculata, the vent chimney-dwelling mussel, Bathymodiolus azoricus, Branchipolynoe seepensis, a commensal worm of B. azoricus and the gastropod Peltospira smaragdina showed variations in As concentration and in stable isotope (δ13C and δ15N) signature between species, suggesting different sources of As uptake. Arsenic speciation showed arsenobetaine to be the dominant species in R. exoculata, whereas in B. azoricus and B. seepensis arsenosugars were most abundant, although arsenobetaine, dimethylarsinate and inorganic arsenic were also observed, along with several unidentified species. Scrape samples from outside the vent chimneys covered with microbial mat, which is a presumed food source for many vent organisms, contained high levels of total As, but organic species were not detectable. The formation of arsenosugars in pelagic environments is typically attributed to marine algae, and the pathway to arsenobetaine is still unknown. The occurrence of arsenosugars and arsenobetaine in these deep sea organisms, where primary production is chemolithoautotrophic and stable isotope analyses indicate food sources are of vent origin, suggests that organic arsenicals can occur in a foodweb without algae or other photosynthetic life.

  2. Delta-proteobacterial SAR324 group in hydrothermal plumes on the South Mid-Atlantic Ridge

    PubMed Central

    Cao, Huiluo; Dong, Chunming; Bougouffa, Salim; Li, Jiangtao; Zhang, Weipeng; Shao, Zongze; Bajic, Vladimir B.; Qian, Pei-Yuan

    2016-01-01

    In the dark ocean, the SAR324 group of Delta-proteobacteria has been associated with a chemolithotrophic lifestyle. However, their electron transport chain for energy generation and information system has not yet been well characterized. In the present study, four SAR324 draft genomes were extracted from metagenomes sampled from hydrothermal plumes in the South Mid-Atlantic Ridge. We describe novel electron transport chain components in the SAR324 group, particularly the alternative complex III, which is involved in energy generation. Moreover, we propose that the C-type cytochrome, for example the C553, may play a novel role in electron transfer, adding to our knowledge regarding the energy generation process in the SAR324 cluster. The central carbon metabolism in the described SAR324 genomes exhibits several new features other than methanotrophy e.g. aromatic compound degradation. This suggests that methane oxidation may not be the main central carbon metabolism component in SAR324 cluster bacteria. The reductive acetyl-CoA pathway may potentially be essential in carbon fixation due to the absence of components from the Calvin-Benson cycle. Our study provides insight into the role of recombination events in shaping the genome of the SAR324 group based on a larger number of repeat regions observed, which has been overlooked thus far. PMID:26953077

  3. A simulation analysis of the fate of phytoplankton within the mid-Atlantic bight

    NASA Technical Reports Server (NTRS)

    Walsh, J. J.; Dieterle, D. A.; Meyers, M. B.

    1986-01-01

    A time-dependent, three-dimensional simulation model of wind-induced changes of the circulation field, of light and nutrient regulation of photosynthesis, of vertical mixing as well as algal sinking, and of herbivore grazing stress, is used to analyze the seasonal production, consumption, and transport of the spring bloom within the mid-Atlantic Bight. The particular case (c) of a 58-day period in February-April 1979, simulated primary production, based on both nitrate and recycled nitrogen, with a mean of 0.62 g C sq m/day over the whole model domain, and an export at the shelf-break off Long Island of 2.60 g ch1 sq m/day within the lower third of the water column. About 57% of the carbon fixation was removed by herbivores, with 21% lost as export, either downshelf or offshore to slope waters, after the first 58 days of the spring bloom. Extension of the model for another 22 days of case (c) increased the mean export to 27%, while variation of the model's parameters in 8 other cases led to a range in export from 8% to 38% of the average primary production. Spatial and temporal variations of the simulated albal biomass, left behind in the shelf water column, reproduced chlorophyll fields sensed by satellite, shipboard, and in situ instruments.

  4. Low-frequency whale and seismic airgun sounds recorded in the mid-Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Nieukirk, Sharon L.; Stafford, Kathleen M.; Mellinger, David K.; Dziak, Robert P.; Fox, Christopher G.

    2004-04-01

    Beginning in February 1999, an array of six autonomous hydrophones was moored near the Mid-Atlantic Ridge (35 °N-15 °N, 50 °W-33 °W). Two years of data were reviewed for whale vocalizations by visually examining spectrograms. Four distinct sounds were detected that are believed to be of biological origin: (1) a two-part low-frequency moan at roughly 18 Hz lasting 25 s which has previously been attributed to blue whales (Balaenoptera musculus); (2) series of short pulses approximately 18 s apart centered at 22 Hz, which are likely produced by fin whales (B. physalus); (3) series of short, pulsive sounds at 30 Hz and above and approximately 1 s apart that resemble sounds attributed to minke whales (B. acutorostrata); and (4) downswept, pulsive sounds above 30 Hz that are likely from baleen whales. Vocalizations were detected most often in the winter, and blue- and fin whale sounds were detected most often on the northern hydrophones. Sounds from seismic airguns were recorded frequently, particularly during summer, from locations over 3000 km from this array. Whales were detected by these hydrophones despite its location in a very remote part of the Atlantic Ocean that has traditionally been difficult to survey.

  5. Tuberculosis control activities before and after Hurricane Sandy--northeast and mid-Atlantic states, 2012.

    PubMed

    2013-03-22

    On October 29, 2012, Hurricane Sandy struck the U.S. northeast and mid-Atlantic seaboard; the effects of the storm extended to southeastern and midwestern states and to eastern Canada. At the time, 1,899 residents in the most affected areas were undergoing treatment for tuberculosis (TB) disease or infection. To ascertain the operational abilities of state and local TB programs during and after the storm and to determine whether lessons learned from a previous hurricane were effective in ensuring continuity of TB patient care, CDC interviewed staff members at all of the affected state and city TB control programs, including those in areas with power outages and flooded streets, tunnels, and subway lines. The interviews determined that continuity of care for TB patients in programs affected by Hurricane Sandy was better preserved than it had been during and after Hurricane Katrina in August 2005. This improvement might be attributed to 1) preparedness measures learned from Hurricane Katrina (e.g., preparing line lists of patients, providing patients with as-needed medications, and making back-up copies of patient records in advance of the storm) and 2) less widespread displacement of persons after Hurricane Sandy than occurred after Hurricane Katrina. Maintaining readiness among clinicians and TB control programs to respond to natural disasters remains essential to protecting public health and preserving TB patients' continuity of care. PMID:23515057

  6. Ground-water vulnerability to nitrate contamination in the mid-atlantic region

    USGS Publications Warehouse

    Greene, Earl A.; LaMotte, Andrew E.; Cullinan, Kerri-Ann; Smith, Elizabeth R.

    2005-01-01

    The U.S. Environmental Protection Agency?s (USEPA) Regional Vulnerability Assessment (ReVA) Program has developed a set of statistical tools to support regional-scale, integrated ecological risk-assessment studies. One of these tools, developed by the U.S. Geological Survey (USGS), is used with available water-quality data obtained from USGS National Water-Quality Assessment (NAWQA) and other studies in association with land cover, geology, soils, and other geographic data to develop logistic-regression equations that predict the vulnerability of ground water to nitrate concentrations exceeding specified thresholds in the Mid-Atlantic Region. The models were developed and applied to produce spatial probability maps showing the likelihood of elevated concentrations of nitrate in the region. These maps can be used to identify areas that currently are at risk and help identify areas where ground water has been affected by human activities. This information can be used by regional and local water managers to protect water supplies and identify land-use planning solutions and monitoring programs in these vulnerable areas.

  7. Diet composition of Bathylagus euryops (Osmeriformes: Bathylagidae) along the northern Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Sweetman, C. J.; Sutton, T. T.; Vecchione, M.; Latour, R. J.

    2014-10-01

    The northern Mid-Atlantic Ridge, from Iceland to the Azores (MAR), is the largest topographical feature in the Atlantic Ocean. Despite its size, few studies have described dietary patterns of pelagic fishes along the MAR. MAR-ECO, a Census of Marine Life field project, aimed to describe the food web structure of abundant fish species along the ridge through a series of research expeditions to the MAR. Among the midwater fishes sampled during the MAR-ECO project, Bathylagus euryops (Osmeriformes: Bathylagidae) was the biomass-dominant pelagic species and ranked third in total abundance. In this paper, we describe the dietary composition of B. euryops along the MAR. Overall, copepods represented the dominant prey group consumed by B. euryops. Multivariate analyses, including a cluster analysis and a canonical correspondence analysis, revealed that fish size significantly influenced the diet of B. euryops with ostracods representing the most important prey group at small sizes (<95 mm) and decapod shrimp and calanoid copepods becoming more important with increasing fish size. Due to the high abundance and biomass observed along the MAR combined with its role as a link for energy transfer between zooplankton and higher trophic level predators, B. euryops appears to be an ecologically important species in the oceanic food web of the North Atlantic Ocean.

  8. Health and climate benefits of offshore wind facilities in the Mid-Atlantic United States

    NASA Astrophysics Data System (ADS)

    Buonocore, Jonathan J.; Luckow, Patrick; Fisher, Jeremy; Kempton, Willett; Levy, Jonathan I.

    2016-07-01

    Electricity from fossil fuels contributes substantially to both climate change and the health burden of air pollution. Renewable energy sources are capable of displacing electricity from fossil fuels, but the quantity of health and climate benefits depend on site-specific attributes that are not often included in quantitative models. Here, we link an electrical grid simulation model to an air pollution health impact assessment model and US regulatory estimates of the impacts of carbon to estimate the health and climate benefits of offshore wind facilities of different sizes in two different locations. We find that offshore wind in the Mid-Atlantic is capable of producing health and climate benefits of between 54 and 120 per MWh of generation, with the largest simulated facility (3000 MW off the coast of New Jersey) producing approximately 690 million in benefits in 2017. The variability in benefits per unit generation is a function of differences in locations (Maryland versus New Jersey), simulated years (2012 versus 2017), and facility generation capacity, given complexities of the electrical grid and differences in which power plants are offset. This work demonstrates health and climate benefits of offshore wind, provides further evidence of the utility of geographically-refined modeling frameworks, and yields quantitative insights that would allow for inclusion of both climate and public health in benefits assessments of renewable energy.

  9. Monitoring stink bugs (Hemiptera: Pentatomidae) in mid-Atlantic apple and peach orchards.

    PubMed

    Leskey, T C; Hogmire, H W

    2005-02-01

    Pyramid traps coated with "industrial safety yellow" exterior latex gloss enamel paint and baited with Euschistus spp. aggregation pheromone, methyl (2E,4Z)-decadienoate captured more stink bugs than all other baited and unbaited trap types in both apple and peach orchards in 2002 and 2003. Commercial sources of dispensers of methyl (2E,4Z)-decadienoate deployed in association with pyramid traps had a significant impact on trap captures. Captures in pyramid traps were four-fold greater when baited with lures from IPM Technologies, Inc. (Portland, OR) than with lures from Suterra (Bend, OR). Variation in yellow pyramid trap color ("industrial safety yellow" and "standard coroplast yellow") and material (plywood, plastic, and masonite) did not affect trap captures. Brown stink bug was the predominant species captured (58%), followed by dusky stink bug, Euschistus tristigmus (Say) (20%); green stink bug, Acrosternum hilare (Say) (14%); and other stink bugs (Brochymena spp. and unidentified nymphs) (8%). Captures in baited pyramid traps were significantly correlated with tree beating samples in both managed and unmanaged apple orchards and with sweep netting samples in the unmanaged apple orchard. However, problems associated with trapping mechanisms of pyramid trap jar tops and jar traps likely resulted in reduced captures in baited traps. Improved trapping mechanisms must be established to develop an effective monitoring tool for stink bugs in mid-Atlantic orchards. PMID:15765676

  10. Near seafloor bioluminescence, macrozooplankton and macroparticles at the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Craig, Jessica; Youngbluth, Marsh; Jamieson, Alan J.; Priede, Imants G.

    2015-04-01

    The benthic boundary layer is a region often perceived to be high in faunal abundance and biomass. In this study, we investigated the distribution of near seafloor bioluminescent zooplankton (BL), macrozooplankton (>1 cm) and macroparticles (>430 μm) at the Northern Mid-Atlantic Ridge at ca. 2500 m depth. At sites south of 52°N, the Charlie Gibbs Fracture Zone, BL density increased weakly towards the seafloor. This trend was driven by small bioluminescent crustaceans, comprising ca. 90% of the total BL density. Macroparticle density was coherent with BL density, exhibiting a small increase towards the seafloor. Appendicularians (animals as well as occupied and discarded houses) were the most abundant macrozooplankton, and the only group to show a significant increase in density towards the seafloor. The absence of pronounced increases in BL and macroparticle density, and no increase in macrozooplankton (except appendicularians), towards the seafloor do not support the conventional view of high concentrations of particulate organic matter and zooplankton biomass in the benthic boundary layer relative to overlying waters.

  11. The Mid-Atlantic Region in Transition: Employment Trends, 1974-84. Rural Development Research Report Number 57.

    ERIC Educational Resources Information Center

    Fuller, Theodore E.

    A comparison of the Mid-Atlantic region (New York, New Jersey, and Pennsylvania) with the nation from 1974 to 1984 revealed that this region trailed New England and the nation in rate of employment growth between 1974-79 and 1979-84. The region had an above-average share of employment in the national fast-growth sectors (services, finance,…

  12. Wave climate model of the Mid-Atlantic shelf and shoreline (Virginian Sea): Model development, shelf geomorphology, and preliminary results

    NASA Technical Reports Server (NTRS)

    Goldsmith, V.; Morris, W. D.; Byrne, R. J.; Whitlock, C. H.

    1974-01-01

    A computerized wave climate model is developed that applies linear wave theory and shelf depth information to predict wave behavior as they pass over the continental shelf as well as the resulting wave energy distributions along the coastline. Reviewed are also the geomorphology of the Mid-Atlantic Continental Shelf, wave computations resulting from 122 wave input conditions, and a preliminary analysis of these data.

  13. Energy landscapes: Coal canals, oil pipelines, and electricity transmission wires in the mid-Atlantic, 1820--1930

    NASA Astrophysics Data System (ADS)

    Jones, Christopher F.

    2009-12-01

    Coal canals, oil pipelines, and electricity transmission wires transformed the built environment of the American mid-Atlantic region between 1820 and 1930. By transporting coal, oil, and electrons cheaply, reliably, and in great quantities, these technologies reshaped the energy choices available to mid-Atlantic residents. In particular, canals, pipelines, and wires created new energy landscapes: systems of transport infrastructure that enabled the ever-increasing consumption of fossil fuels. Energy Landscapes integrates history of technology, environmental history, and business history to provide new perspectives on how Americans began to use fossil fuels and the social implications of these practices. First, I argue that the development of transport infrastructure played critical, and underappreciated, roles in shaping social energy choices. Rather than simply responding passively to the needs of producers and consumers, canals, pipelines, and wires structured how, when, where, and in what quantities energy was used. Second, I analyze the ways fossil fuel consumption transformed the society, economy, and environment of the mid-Atlantic. I link the consumption of coal, oil, and electricity to the development of an urban and industrialized region, the transition from an organic to a mineral economy, and the creation of a society dependent on fossil fuel energy.

  14. Inorganic and organic nitrogen uptake by phytoplankton and heterotrophic bacteria in the stratified Mid-Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Bradley, Paul B.; Sanderson, Marta P.; Frischer, Marc E.; Brofft, Jennifer; Booth, Melissa G.; Kerkhof, Lee J.; Bronk, Deborah A.

    2010-08-01

    Little is known about the relative importance of inorganic and organic nitrogen (N) sources in fueling production of phytoplankton versus heterotrophic bacteria on the continental shelf. This issue was addressed during two diel experiments conducted in the Mid-Atlantic Bight at the Long-term Ecosystem Observatory, LEO-15, off southern New Jersey. Uptake of 15N-labeled ammonium (NH 4+), nitrate (NO 3-), and nitrite (NO 2-), and dual-labeled ( 15N and 13C) urea and dissolved free amino acids was measured in water taken from the surface and bottom mixed layers approximately every 4 h over two 24 h periods in July 2002. Two methods were used to quantify 15N uptake rates: (1) traditional filtration into various phytoplankton and bacterial size classes, and (2) flow cytometric (FCM) sorting of autotrophic cells based on the presence of chlorophyll autofluorescence. Due to a strong pycnocline, the nutrient composition was quite distinct between the surface and bottom mixed layers. Dissolved organic N (DON) comprised >99% of the total dissolved N (TDN) pool in surface waters, whereas the bottom-water TDN pool was roughly divided between NH 4+, NO 3-, and DON. Urea was the dominant N form used by all fractions at the surface, and although phytoplankton >3 μm was responsible for most of the urea uptake, bacterial use was detected using stable isotopes and also suggested by ureC sequence analysis. The majority of ureC sequences recovered from the 0.2-0.8 μm fraction belonged to members of the Alphaproteobacteria (46%), whereas those of the 0.8-3.0 μm size class consisted primarily of Cyanobacteria (70%). In contrast to the surface, N uptake in the bottom layer was dominated by NH 4+. The bacterial fraction was responsible for 20-49% of the size-fractionated NH 4+ and NO 3- uptake in surface samples and 36-93% at the bottom. These results suggest that organic N, such as urea, is a viable source of N nutrition to phytoplankton forced to compete with heterotrophic bacteria

  15. 75 FR 67083 - Magnuson-Stevens Act Provisions; General Provisions for Domestic Fisheries; Application for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-01

    ... SNE Flatfish Discard Mortality EFP.'' Comments may also be sent via facsimile (fax) to (978) 281-9135... Southern New England (SNE) Flatfish Discard Mortality Study conducted by the University of Massachusetts... mortality of flatfish discarded in SNE and Mid-Atlantic trawl fisheries. The researchers would conduct...

  16. Impacts of interstate transport of pollutants on high ozone events over the Mid-Atlantic United States

    NASA Astrophysics Data System (ADS)

    Liao, Kuo-Jen; Hou, Xiangting; Baker, Debra Ratterman

    2014-02-01

    The impacts of interstate transport of anthropogenic nitrogen oxides (NOx) and volatile organic compound (VOC) emissions on peak ozone formation in four nonattainment areas (i.e., Baltimore, Philadelphia-Wilmington-Atlantic City, Pittsburgh-Beaver Valley and Washington, DC) in the Mid-Atlantic U.S. were quantified in this study. Regional air quality and sensitivities of ground-level ozone to emissions from four regions in the eastern U.S. were simulated for three summer months (June, July and August) in 2007 using the U.S. EPA's Community Multiscale Air Quality model with the decoupled direct method 3D. The emissions inventory used in this study was the 2007 Mid-Atlantic Regional Air Management Association Level 2 inventory, developed for State Implementation Plan screening modeling for the Ozone Transport Commission region. The modeling results show that responses of peak ozone levels at specific locations to emissions from EGU (i.e., electric generating unit) and non-EGU sources could be different. Therefore, emissions from EGU and non-EGU sources should be considered as two different control categories when developing regional air pollution mitigation strategies. Based on the emission inventories used in this study, reductions in anthropogenic NOx emissions (including those from EGU and non-EGU sources) from the Great Lake region as well as northeastern and southeastern U.S. would be effective for decreasing area-mean peak ozone concentrations during the summer of 2007 in the Mid-Atlantic ozone air quality nonattainment areas. The results also show that reductions in anthropogenic VOC emissions from the northeastern U.S. would also be effective for decreasing area-mean peak ozone concentrations over the Mid-Atlantic U.S. In some cases, reductions in anthropogenic NOx emissions from the Great Lake and northeastern U.S. could slightly increase area-mean peak ozone concentrations at some ozone monitors in the Pittsburgh-Beaver Valley and Washington, DC areas

  17. Landscape correlates of breeding bird richness across the United States mid-Atlantic region

    USGS Publications Warehouse

    Jones, K.B.; Neale, A.C.; Nash, M.S.; Riitters, K.H.; Wickham, J.D.; O'Neill, R. V.; Van Remortel, R. D.

    2000-01-01

    Using a new set of landscape indicator data generated by the U.S.EPA, and a comprehensive breeding bird database from the National Breeding Bird Survey, we evaluated associations between breeding bird richness and landscape characteristics across the entire mid-Atlantic region of the United States. We evaluated how these relationships varied among different groupings (guilds) of birds based on functional, structural, and compositional aspects of individual species demographics. Forest edge was by far the most important landscape attribute affecting the richness of the lumped specialist and generalist guilds; specialist species richness was negatively associated with forest edge and generalist richness was positively associated with forest edge. Landscape variables (indicators) explained a greater proportion of specialist species richness than the generalist guild (46% and 31%, respectively). The lower value in generalists may reflect freer-scale distributions of open habitat that go undetected by the Landsat satellite, open habitats created by roads (the areas from which breeding bird data are obtained), and the lumping of a wide variety of species into the generalist category. A further breakdown of species into 16 guilds showed considerable variation in the response of breeding birds to landscape conditions; forest obligate species had the strongest association with landscape indicators measured in this study (55% of the total variation explained) and forest generalists and open ground nesters the lowest (17% of the total variation explained). The variable response of guild species richness to landscape pattern suggests that one must consider species' demographics when assessing the consequences of landscape change on breeding birds.Using a new set of landscape indicator data generated by the U.S. EPA, and a comprehensive breeding bird database from the National Breeding Bird Survey, we evaluated associations between breeding bird richness and landscape

  18. Igneous Crystallization Beginning at 20 km Beneath the Mid-Atlantic Ridge, 14 to 16 N

    NASA Astrophysics Data System (ADS)

    Kelemen, P.

    2003-12-01

    ODP Leg 209 drilled 19 holes at 8 sites along the Mid-Atlantic Ridge from 14° 43 to 15° 44 N. All sites were previously surveyed by submersible, and were chosen to be < 200 m from peridotite or dunite exposed on the seafloor; outcrops of gabbroic rock were also near some sites. One primary goal of Leg 209 was to constrain melt migration and igneous petrogenesis in this region where residual peridotites are exposed on both sides of the Ridge axis. At Sites 1269 and 1273, we penetrated 112 m of basaltic rubble; recovery was poor (3.7 m) and holes unstable, so drilling was terminated. Lavas form nearly horizontal surfaces overlying cliffs exposing peridotite and gabbro. At 6 other sites, we drilled a mixture of residual peridotite and gabbroic rocks intrusive into peridotite. We penetrated 1075 meters at these 6 sites, and recovered 354 m of core. Drilling at Sites 1268, 1270, 1271 and 1272 recovered 25% gabbroic rocks and 75% residual mantle peridotite. Core from Site 1274 is mainly residual peridotite, with a few m-scale gabbroic intrusions. Core from Site 1275 is mainly gabbroic, but contains 24% poikilitic lherzolite interpreted as residual peridotite "impregnated" by plagioclase and pyroxene crystallized from melt migrating along olivine grain boundaries; these impregnated peridotites were later intruded by evolved gabbros. Impregnated peridotites are also common at Site 1271, and present at Sites 1268 and 1270. The overall proportion of gabbroic rocks versus residual peridotites from these 6 sites is similar to previous dredging and submersible sampling in the area. The proportion of gabbro is larger than in"amagmatic" regions on the ultra-slow spreading SWIR and Gakkel Ridges. Impregnated peridotites from Site 1275 have "equilibrated" textures and contain olivine, 2 pyroxenes, plag and Cr-rich spinel. Their whole rock Mg#, Cr# and Ni are high, extending to residual peridotite values. 87 MORB glasses from 14 to 16° N with Mg# from 60 to 73 [from PetDB] could

  19. Distribution of Seismicity and thermal structure at Lucky Strike Hydrothermal Segment of Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Rai, A.; Singh, S. C.; Crawford, W. C.; Escartin, J.; Cannat, M.; Seher, T.

    2009-12-01

    The Lucky-strike segment (37.2 deg. N), located at the slow-spreading Mid-Atlantic Ridge (MAR) south of the Azores hot-spot, is characterized by a large hydrothermal field underlain by a 3-km deep magma chamber. To study the seismic activity in the Lucky-strike segment, four short-period and one broad-band ocean-bottom seismometers (OBSs) were deployed in a diamond shape at an spacing of 4.5 km, and centered at the hydrothermal field. These five OBSs recorded two horizontal, one vertical and one pressure channels, over a period of 13 months (06/08-08/09) as a part of the BBMOMAR experiment. All the five equipments have recorded large number of micro-earthquakes, earthquake swarms and teleseismic earthquakes. Here, we present the preliminary analysis of distribution of micro-seismicity in and around the Lucky-strike segment. We have detected about 6000 earthquakes to date. Out of these, we have located about 800 earthquakes which have been recorded by at-least four equipments with clear P- and S- arrivals. The distribution of earthquakes show a concentration of events at both inside corners North and South of the Lucky Strike segment, reaching maximum depths of more than 10 km, and a relative low number of events at the segment center, below the central volcano, with maximum depths reaching only 6 km. We have also identified several swarm activity in the region. This study will be extended to include the new data of 8/08-9/09 time period, after recovery and redeployment of instruments during the BATHYLUCK09 cruise. These additional data will thus provide the best constraints to date on the thermal structure throughout the segment and around the magma chamber at its center, and intern on the links between hydrothermal activity and deformation of the oceanic lithosphere at this site.

  20. Genetic Connectivity between North and South Mid-Atlantic Ridge Chemosynthetic Bivalves and Their Symbionts

    PubMed Central

    van der Heijden, Karina; Petersen, Jillian M.; Dubilier, Nicole; Borowski, Christian

    2012-01-01

    Transform faults are geological structures that interrupt the continuity of mid-ocean ridges and can act as dispersal barriers for hydrothermal vent organisms. In the equatorial Atlantic Ocean, it has been hypothesized that long transform faults impede gene flow between the northern and the southern Mid-Atlantic Ridge (MAR) and disconnect a northern from a southern biogeographic province. To test if there is a barrier effect in the equatorial Atlantic, we examined phylogenetic relationships of chemosynthetic bivalves and their bacterial symbionts from the recently discovered southern MAR hydrothermal vents at 5°S and 9°S. We examined Bathymodiolus spp. mussels and Abyssogena southwardae clams using the mitochondrial cytochrome c oxidase subunit I (COI) gene as a phylogenetic marker for the hosts and the bacterial 16S rRNA gene as a marker for the symbionts. Bathymodiolus spp. from the two southern sites were genetically divergent from the northern MAR species B. azoricus and B. puteoserpentis but all four host lineages form a monophyletic group indicating that they radiated after divergence from their northern Atlantic sister group, the B. boomerang species complex. This suggests dispersal of Bathymodiolus species from north to south across the equatorial belt. 16S rRNA genealogies of chemoautotrophic and methanotrophic symbionts of Bathymodiolus spp. were inconsistent and did not match the host COI genealogy indicating disconnected biogeography patterns. The vesicomyid clam Abyssogena southwardae from 5°S shared an identical COI haplotype with A. southwardae from the Logatchev vent field on the northern MAR and their symbionts shared identical 16S phylotypes, suggesting gene flow across the Equator. Our results indicate genetic connectivity between the northern and southern MAR and suggest that a strict dispersal barrier does not exist. PMID:22792208

  1. Negative gravity anomaly over spreading rift valleys: Mid-Atlantic Ridge at 26°N

    NASA Astrophysics Data System (ADS)

    Bowin, Carl; Milligan, Julie

    1985-03-01

    A pronounced negative free-air gravity anomaly commonly occurs over the median valley of slow spreading ocean ridges. Previous results, using Wiener filtering and cross-spectral analysis techniques for the Mid-Atlantic Ridge, obtained estimates of the elastic plate thickness in the range of 7-13 km and the existence of a residual negative gravity anomaly over the median rift valley, suggesting that the rift valley has a response function different than the remainder of the spreading ridge. In this paper we have improved the derivation of the topography-gravity admittance function for spreading ocean crust by carefully avoiding several sources of spectral splattering when processing the data: (1) selecting data from a cruise that followed a flowline of central North Atlantic relative plate motion and hence is least corrupted by fracture zones; and (2) accounting for the difference in distance between the gravity meter and the regional variation in elevation as the ridge crest is traversed. Improvements of lesser importance include the use of cubic splines to interpolate to equally spaced data rather than linear interpolation, and correction of the free-air anomaly values for long-wavelength variations of the indirect effect. Comparison of the resulting admittance function to elastic flexure response functions suggests an elastic plate thickness of about 8 km. The improved admittance function, when convolved with the ridge topography, provides a predicted gravity profile that accounts very well for the negative anomaly over the rift valley. Therefore, the isostatic response function for the rift valley is similar to that for the topography away from the rift valley.

  2. Seismogenic behavior of symmetric vs. detachment-dominated sections of the Northern Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Olive, J. A. L.; Escartin, J.

    2015-12-01

    Normal faults are essential in shaping the seafloor formed at slow-spreading mid-ocean ridges, and information on their behavior on short (seismic cycle) time scales is limited. Here we combine catalogs of hydro-acoustically recorded [Bohnenstiehl et al., 2000; 2002] and teleseismic earthquakes to analyze the modes of seismic moment release along the Northern Mid-Atlantic Ridge between the Marathon (12ºN) and Oceanographer (35ºN) Fracture Zones. Along about 50% of the ridge axis, tectonic extension is taken up by steep, symmetric conjugate faults that bound a well-defined axial valley. By contrast, along the remaining 50% most of the tectonic strain is accommodated by large-offset detachment faults [Escartín et al., 2008]. Upon declustering the catalogs to remove major aftershock sequences, we estimate seismicity rates and infer seismic moment release along the ridge axis by converting hydro-acoustic source level to moment magnitude. The shape of the resulting cumulative moment release curves is then investigated at individual ridge sections defined by tectonic interpretation of seafloor morphology. Qualitatively, the seismogenic behavior of symmetric sections appears more stick slip-like (with large events separated by a few years of relative quiescence) than that of detachment-dominated sections, which feature more frequent, smaller events. We quantify these differences by measuring relevant parameters (e.g., background seismicity rates, b-values...) along different tectonic ridge sections, as well as along sliding windows with no prior knowledge of the seafloor morphology. Finally, we assess possible relations between the observed contrasted seismogenic behavior and the systematic variations in fault geometry and rheology (dip, offset, cross-axis and down-dip extent, presence of weak minerals in the fault zone) inferred from seafloor observations along slow-spreading ridges.

  3. Antioxidant systems and lipid peroxidation in Bathymodiolus azoricus from Mid-Atlantic Ridge hydrothermal vent fields.

    PubMed

    Bebianno, M J; Company, R; Serafim, A; Camus, L; Cosson, R P; Fiala-Médoni, A

    2005-11-30

    Enzymatic defenses involved in protection from oxygen radical damage were determined in gills and mantle of Bathymodiolus azoricus collected from three contrasting Mid-Atlantic Ridge (MAR) hydrothermal vent fields (Menez-Gwen, Lucky Strike and Rainbow). The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidases (GPx) (total and Se-dependent), and levels of total oxyradical scavenging capacity (TOSC), metallothioneins (MT) and lipid peroxidation (LPO) were determined in B. azoricus tissues and the impact of metal concentrations on these antioxidant systems and lipid peroxidation assessed. SOD, CAT, TOSC, MTs and LPO levels were higher in B. azoricus gills while glutathione peroxidases (total and Se-dependent) were higher in the mantle, and with the exception of CAT, were of the same order of magnitude as in other molluscs. TOSC levels from Menez-Gwen indicate that the vent environment at this site is less stressful and the formation of ROS in mussels is effectively counteracted by the antioxidant defense system. TOSC depletion indicates an elevated ROS production in molluscs at the other two vent sites. Cytosolic SOD, GPx and LPO were more relevant at Lucky Strike (Bairro Alto) where levels of essential (Cu and Zn) and toxic metals (Cd and Ag) were highest in the organisms. CAT activity and LPO were predominant at the Rainbow vent site, where an excess of Fe in mussel tissues and in vent fluids (the highest of all three vent sites) may have contributed to increased LPO. Therefore, three distinct pathways for antioxidant enzyme systems and LPO based on environmental metal speciation of MAR vent fields are proposed for Bathymodiolus gills. At Menez-Gwen, TOSC towards peroxyl and hydroxyl radicals and peroxynitrite are predominant, while at Lucky Strike cytosolic SOD activity and GPx are the main antioxidant mechanisms. Finally at Rainbow, catalase and lipid peroxidation are dominant, suggesting that resistance of mussels to metal toxicity at

  4. Temporal trends in nitrate and selected pesticides in Mid-Atlantic ground water.

    PubMed

    Debrewer, Linda M; Ator, Scott W; Denver, Judith M

    2008-01-01

    Evaluating long-term temporal trends in regional ground-water quality is complicated by variable hydrogeologic conditions and typically slow flow, and such trends have rarely been directly measured. Ground-water samples were collected over near-decadal and annual intervals from unconfined aquifers in agricultural areas of the Mid-Atlantic region, including fractured carbonate rocks in the Great Valley, Potomac River Basin, and unconsolidated sediments on the Delmarva Peninsula. Concentrations of nitrate and selected pesticides and degradates were compared among sampling events and to apparent recharge dates. Observed temporal trends are related to changes in land use and chemical applications, and to hydrogeology and climate. Insignificant differences in nitrate concentrations in the Great Valley between 1993 and 2002 are consistent with relatively steady fertilizer application during respective recharge periods and are likely related to drought conditions in the later sampling period. Detecting trends in Great Valley ground water is complicated by long open boreholes characteristic of wells sampled in this setting which facilitate significant ground-water mixing. Decreasing atrazine and prometon concentrations, however, reflect reported changes in usage. On the Delmarva Peninsula between 1988 and 2001, median nitrate concentrations increased 2 mg per liter in aerobic ground water, reflecting increasing fertilizer applications. Correlations between selected pesticide compounds and apparent recharge date are similarly related to changing land use and chemical application. Observed trends in the two settings demonstrate the importance of considering hydrogeology and recharge date along with changing land and chemical uses when interpreting trends in regional ground-water quality. PMID:18765775

  5. Community composition of scavenging amphipods at bathyal depths on the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Horton, Tammy; Thurston, Michael H.; Duffy, Grant A.

    2013-12-01

    This study focussed on a section of the Mid-Atlantic Ridge with one pair of sampling areas at 49°N and the other at 54°N, north and south of the Charlie-Gibbs Fracture Zone and east and west of the ridge, at a water depth of 2500 m. Sixteen baited-trap samples of necrophagous amphipods were collected during three research cruises on the R.R.S. James Cook in 2007, 2009 and 2010. Amphipods of the superfamily Lysianassoidea are numerically dominant and taxonomically diverse and form the most important group of necrophages in most deep-sea environments. A total of 39 scavenging species from 253,306 specimens were identified at the four sampling areas over the 4-year study period. Less than half of the entities could be ascribed to known species. More than 25% of the species recorded were found at all of the sampling areas, supporting the view that necrophagous amphipods are widely distributed animals. The number of lysianassoid species (31) was higher than expected when compared with other studies of necrophagous amphipods, particularly as all sampling was done at one depth (2500 m). Deep-sea scavenging amphipods are generally thought to have low diversity and previous studies have supported this view. Sample sizes were large with some traps containing more than 40,000 specimens. The most abundant species, Abyssorchomene abyssorum, dominated all trap samples with percentage compositions over 90% at the NE sites in 2009-2010. Univariate and Multivariate analyses indicated a significant difference in community composition and species richness between the northern and southern stations. There are at least 15 new species to be described from these samples, and particular effort is required in the genus Paracallisoma and the genus Tryphosella.

  6. Population genetic structure of the abyssal grenadier (Coryphaenoides armatus) around the mid-Atlantic ridge

    NASA Astrophysics Data System (ADS)

    Ritchie, H.; Cousins, N. J.; Cregeen, S. J.; Piertney, S. B.

    2013-12-01

    Understanding the factors that affect the levels and distribution of genetic diversity in oceanic and deep sea environments is a central focus in marine population genetics. Whilst it has been considered that the oceans represent a homogenous environment that would facilitate dispersal and minimise population structure, it is now clear that topographical features and current patterns can influence the extent of spatial gene flow and promote significant population genetic divergence even at local scales. Here we examine patterns of population genetic structure among N. Atlantic populations of the cosmopolitan abyssal grenadier Coryphaenoides armatus in relation to two hypothesised barriers to gene flow-the mid-Atlantic Ridge and the Charlie-Gibbs Fracture Zone/Sub-Polar Front. A suite of microsatellite markers were developed to examine the spatial pattern of allelic variation among 210 individuals from ten sampling locations encompassing sites east and west of the MAR and north and south of the CGFZ, plus a geographically distinct sample of individuals from the Crozet Islands in the Indian Ocean. Considerable genetic diversity was detected among individuals (na=5-13 and HO=0.46-0.69 across populations) but with an overall lack of genetic divergence between populations. Pairwise estimates of divergence among NE Atlantic samples were small and non-significant (max FST=0.04) and Structure-based Bayesian analysis of genetic clusters returned no distinct population structure. The only indication of genetic structure was between the Atlantic and Indian Oceans, with FST estimates of ca. 0.05. Patterns of genetic diversity and divergence are discussed in relation to what has been resolved in Coryphaenoides congeners, and what is known about the life history and ecology of C. armatus.

  7. Abundance and distribution of fatty acids in sediments of the South Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Huang, Xin; Zeng, Zhigang; Chen, Shuai; Yin, Xuebo; Wang, Xiaoyuan; Ma, Yao; Yang, Baoju; Rong, Kunbo; Shu, Yunchao; Jiang, Tao

    2015-04-01

    Sediment samples obtained from the South Mid-Atlantic Ridge were studies by gas chromatography-mass spectrometer (GC-MS) for the abundance and distributions of total fatty acids (TFAs). Approximately 34 fatty acids were identified, with the chain-lengths ranging from C12 to C30. The total concentrations of TFAs (ΣTFA) ranged from 7.15 to 30.09 μg g-1 dry sediment, and ΣTFA was weakly correlated with bitumen content ( R 2 = 0.69). The ΣTFA of samples around hydrothermal areas were significantly higher than that of samples away from hydrothermal areas, indicating intense primary production and large biomass in the hydrothermal areas, and suggesting a close relationship between hydrothermal activity and ΣTFA of samples. The characteristics of the TFA composition in the present study are rich in monounsaturated fatty acids and lacking in polyunsaturated fatty acids, and the ratios between the concentrations of monounsaturated fatty acids and ΣTFAs in samples close to the hydrothermal areas, are about 0.8, but for samples far from the hydrothermal areas, they are only about 0.5. Several fatty acids ( e.g., a/iC15:0 and C16:1ω7), which are signature biomarkers for sulfur-metabolizing bacteria, show the same distribution trend as ΣTFA of samples, further highlighting the close relationship between fatty acid content and hydrothermal activity and/or hydrothermal communities. The metabolic activities of hydrothermal communities, especially those of microorganisms, are likely the main source of fatty acids in samples.

  8. Origin and fate of the North Atlantic Current at the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Breckenfelder, Tilia; Myers, Paul G.; Rhein, Monika; Pennelly, Clark; Hu, Xianmin

    2016-04-01

    Warm, salty tropical and subtropical water is brought into the subpolar gyre by the North Atlantic Current (NAC). The NAC is the northward extension of the Gulf Stream and is part of the upper branch of the Atlantic Meridional Overturning Circulation. The warm, salty water is further transported into the Nordic Seas via the Rockall Trough, into the Denmark Strait and, finally into the Labrador Sea, where it plays an important role in the deep water formation process. On its way into the Labrador Sea the water mass increases its density by dissipating heat to the atmosphere and thereby influencing the local climate. To further understand the processes behind warm water transport towards higher latitudes, we start our investigation at the Mid-Atlantic Ridge (MAR). Here, the NAC flows from the western to eastern basin of the North Atlantic and crosses the MAR via the Charlie-Gibbs, Faraday and Maxwell Fracture Zones. The role of the subpolar and subtropical gyre on the different water masses, and their properties, originating or reaching the MAR is studied using the lagrangian tool ARIANE with the 3D velocity fields taken from a 1/12° AGRIF nest set in a regional NEMO configuration. One result of this investigation is that the majority of particles released at the MAR, distributed over the entire water column, recirculate. Most of the remaining particles make their way into the East Greenland Current or turn in the eastern basin towards the south. The influence of the North Atlantic Oscillation (NAO) is investigated by studying the pathways of the NAC and their properties during different NAO phases.

  9. Evidence for accumulated melt beneath the slow-spreading Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Sinha, M. C.; Navin, D. A.; MacGregor, L. M.; Constable, S.; Peirce, C.; White, A.; Heinson, G.; Inglis, M. A.

    The analysis of data from a multi-component geophysical experiment conducted on a segment of the slow-spreading (20 mm yr-1) Mid-Atlantic Ridge shows compelling evidence for a significant crustal magma body beneath the ridge axis. The role played by a crustal magma chamber beneath the axis in determining both the chemical and physical architecture of the newly formed crust is fundamental to our understanding of the accretion of oceanic lithosphere at spreading ridges, and over the last decade subsurface geophysical techniques have successfully imaged such magma chambers beneath a number of intermediate and fast spreading (60-140 mm yr-1 full rate) ridges. However, many similar geophysical studies of slow-spreading ridges have, to date, found little or no evidence for such a magma chamber beneath them. The experiment described here was carefully targeted on a magmatically active, axial volcanic ridge (AVR) segment of the Reykjanes Ridge, centred on 57 degrees 43 minutes North. It consisted of four major components: wide-angle seismic profiles using ocean bottom seismometers; seismic reflection profiles; controlled source electromagnetic sounding; and magneto-telluric sounding. Interpretation and modelling of the first three of these datasets shows that an anomalous body lies at a depth of between 2 and 3 km below the seafloor beneath the axis of the AVR. This body is characterized by anomalously low seismic P-wave velocity and electrical resistivity, and is associated with a seismic reflector. The geometry and extent of this melt body shows a number of similarities with the axial magma chambers observed beneath ridges spreading at much higher spreading rates. Magneto-telluric soundings confirm the existence of very low electrical resistivities in the crust beneath the AVR and also indicate a deeper zone of low resistivity within the upper mantle beneath the ridge.

  10. Crystallization depth beneath an oceanic detachment fault (ODP Hole 923A, Mid-Atlantic Ridge)

    NASA Astrophysics Data System (ADS)

    Lissenberg, C. Johan; Rioux, Matthew; MacLeod, Christopher J.; Bowring, Samuel A.; Shimizu, Nobumichi

    2016-01-01

    Oceanic detachment faults are increasingly recognized as playing an integral role in the seafloor spreading process at slow and ultraslow spreading mid-ocean ridges, with significant consequences for the architecture of the oceanic lithosphere. Although melt supply is considered to play a critical control on the formation and evolution of oceanic detachments, much less well understood is how melts and faults interact and influence each other. Few direct constraints on the locus and depth of melt emplacement in the vicinity of detachments are available. Gabbros drilled in ODP Hole 923A near the intersection of the Mid-Atlantic Ridge and the Kane transform fault (23°N; the MARK area) represent magmas emplaced into the footwall of such a detachment fault and unroofed by it. We here present U-Pb zircon dates for these gabbros and associated diorite veins which, when combined with a tectonic reconstruction of the area, allow us to calculate the depths at which the melts crystallized. Th-corrected single zircon U-Pb dates from three samples range from 1.138 ± 0.062 to 1.213 ± 0.021 Ma. We find a crystallization depth of 6.4 +1.7/-1.3 km, and estimate that the melts parental to the gabbros were initially emplaced up to 1.5 km deeper, at <8 km below the seafloor. The tectonic reconstruction implies that the detachment fault responsible for the exposure of the sampled sequence likely crossed the ridge axis at depth, suggesting that melt emplacement into the footwall of oceanic detachment faults is an important process. The deep emplacement depth we find associated with "detachment mode" spreading at ˜1.2 Ma appears to be significantly greater than the depth of magma reservoirs during the current "magmatic mode" of spreading in the area, suggesting that the northern MARK segment preserves a recent switch between two temporally distinct modes of spreading with fundamentally different lithospheric architecture.

  11. National Assessment of Shoreline Change; historical shoreline change along the New England and Mid-Atlantic coasts

    USGS Publications Warehouse

    Hapke, Cheryl J.; Himmelstoss, Emily A.; Kratzmann, Meredith G.; List, Jeffrey H.; Thieler, E. Robert

    2011-01-01

    Beach erosion is a chronic problem along many open-ocean shores of the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information regarding past and present trends and rates of shoreline movement. There is also a need for a comprehensive analysis of shoreline movement that is consistent from one coastal region to another. To meet these national needs, the U.S. Geological Survey (USGS) is conducting an analysis of historical shoreline changes along open-ocean sandy shores of the conterminous United States and parts of Hawaii, Alaska, and the Great Lakes. One purpose of this work is to develop standard, repeatable methods for mapping and analyzing shoreline movement so that periodic, systematic, internally consistent updates regarding coastal erosion and land loss can be made nationally. In the case of this study, the shoreline is the interpreted boundary between the ocean water surface and the sandy beach. This report on the New England and Mid-Atlantic coasts is the fifth in a series of reports on historical shoreline change. Previous investigations include analyses and descriptive reports of the Gulf of Mexico, the Southeast Atlantic, and, for California, the sandy shoreline and the coastal cliffs. The rates of change presented in this report represent conditions up to the date of the most recent shoreline data and therefore are not intended for predicting future shoreline positions or rates of change. Because of the geomorphology of the New England and Mid-Atlantic (rocky coastlines, large embayments and beaches) as well as data gaps in some areas, this report presents beach erosion rates for 78 percent of the 1,360 kilometers of the New England and Mid-Atlantic coasts. The New England and Mid-Atlantic shores were subdivided into a total of 10 analysis regions for the purpose of reporting regional trends in shoreline change rates. The average rate of long

  12. Heat and Volume Fluxes at the Turtle Pits Vent Site, southern Mid Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Köhler, Janna; Walter, Maren; Mertens, Christian; Sültenfuß, Jürgen; Rhein, Monika

    2010-05-01

    The Turtle Pits vent site consists of eight known high temperature vents and several diffuse vent sites which are distributed over three hydrothermal fields: Turtle Pits, Comfortless Cove, and Red Lion. These vent fields are located in a north-south orientated rift valley at the Mid-Atlantic Ridge (MAR) near 5°S. The total volume and heat emissions of the entire Turtle Pits site have been calculated with three different approaches using data collected during a Meteor cruise in May 2006 and a L'Atalante cruise in January 2008. The data sets consist of vertical profiles and towed transects of temperature, salinity, and turbidity, as well as direct velocity measurements with a lowered acoustic Doppler current profiler (LADCP) and water samples for Helium isotope analysis. Vent fluid samples for noble gas analysis where taken with ROVs. Since the vent fluid is highly enriched in primordial 3He this noble gas can be used as a conservative tracer for vent fluid. The geographical setting of the vent site confines the particle plume to the rift valley since the depth of the valley exceeds the rise height of the plume. Therefore the fluxes of heat and volume can be estimated from the horizontal helium transport in the valley in combination with a mean 3He endmember concentration determined from the water samples taken with the ROVs. The comparison of the 3He concentrations measured south of the hydrothermal vents with the 3He signal north of the hydrothermal vents suggests a rather strong northward flow. This is confirmed by the tide corrected velocities observed with the LADCP during the Meteor cruise. The northward volume transport has been calculated using the local bathymetry and tide corrected velocities from the Meteor cruise. In combination with the 3He concentrations and the average 3He endmember concentration a flux of 1000 l/s is estimated, which corresponds to a heat flux of 1400 MW. The measured temperature anomalies within the plume combined with the known

  13. Diffusion transport model for pelagic sediments on the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Mitchell, Neil C.

    1995-10-01

    The diffusion model is potentially useful for quantifying the effect of downslope gravity transport on sedimentation rate variations, which are commonly found between Deep Sea Drilling Project and Ocean Drilling Program sites. If appropriate, the model and stratigraphy could be used, for example, to constrain the amount and timing of fault block rotation. Deep Tow profiler records from the French-American Mid-Ocean Undersea Study area of the Mid-Atlantic Ridge are examined to determine whether they are consistent with a diffusion model. Sedimentary contacts with basement show that a variety of processes may be operating, some of which are inconsistent with the diffusion model. For example, there are moats around some contacts which are typical of scouring or nondeposition due to high current velocities. More than half of the contacts, however, show onlapping, which is qualitatively consistent with the diffusion model. Sediments generally fill low areas of the topography and have smooth surfaces, as expected from a diffusion model. Where the fluxes of sediment entering a basin are constant, the diffusion model predicts that the sediment surface should evolve to a parabola (the steady state solution). Some 20 curved surfaces in the profiler data were digitized and least squares parabolas fitted to them with rms errors of less than 1 m. The slopes of the model parabolas provide values for the ratio of sediment flux to diffusivity at the edges of the basins (steep surfaces are produced by low diffusivity or high fluxes). This ratio is combined with estimates of the fluxes to determine the apparent sediment diffusivity, Kapp, for eacri basin. Flux is estimated by assuming the abyssal hill topography acts as a simple sediment trap, so that the lateral flux equals the width of a basin's pelagic catchment area times the area's mean sedimentation rate S. Using this method, median Kapp is 0.04-0.11 m2 yr-1 (assuming S = 10-30 m m.y.-1). Variations in Kapp and the assumptions

  14. The Distribution and Abundance of Mercury Methylating Microorganisms in Mid-Atlantic Wetlands

    NASA Astrophysics Data System (ADS)

    Santillan, E. F. U.; Gilmour, C. C.; Schwartz, G.; Christensen, G. A.; King, A. J.; Elias, D. A.

    2015-12-01

    The discovery of the genes responsible for microbial methylmercury production, hgcAB, has led to the identification of novel Hg methylators with diverse metabolisms including Fe and SO42- reducing bacteria, syntrophs, and methanogens. We recently developed DNA probes for hgcA in each group of methylators: Deltaproteobacteria, Firmicutes, and Archaea [Christensen, 2015]. In this study, we use the probes to determine quantity and distribution of hgcA+ organisms in mid-Atlantic marshes and sediments, and in Hg-contaminated wetland soils. We also analyze hgcA distribution over a 28-day soil slurry experiment designed to evaluate the impact of activated carbon on Hg methylation and demethylation [Gilmour, 2015]. Initial soils show Deltaproteobacteria comprise most hgcA+ organisms. Methanogens encompass >45% of the remaining methylators. The addition of SO42- to induce SO42- reducing conditions in slurries caused the number of hgcA+ Deltaproteobacteria to increase and the number of hgcA+ methanogens to decrease to >32%. In soils and slurries, Firmicutes were below detection, suggesting our Firmicute primers are either unrepresentative in natural samples, or that hgcA+ Firmicutes are rare. This observation is interesting as Firmicutes include organisms with divergent metabolisms, and their role in environmental methylation is still unknown. Slurries also show no correlation between hgcA abundance and Hg concentrations. We now plan to explore how hgcA abundance relates to Hg-methylation and electron acceptor availability. Our results offer initial insights into the natural distribution of hgcA, supporting the idea that the distribution of different methylators is related to electron acceptors and redox chemistry. Christensen, G., Wymore, AM, King, A, Pdar, M, Hurt Jur, RA, Santillan, EFU, Gilmour, CC, Brandt, CC, Brown, SD, Palumbo, AV, Elias, DA (2015), A Study of Mercury Methylation Genetics: Qualitative and Quantitative Analysis of hgcAB in Pure Culture, paper presented

  15. Potential effects of climate change on freshwater ecosystems of the New England/Mid-Atlantic Region

    USGS Publications Warehouse

    Moore, M.V.; Pace, M.L.; Mather, J.R.; Murdoch, Peter S.; Howarth, R.W.; Folt, C.L.; Chen, C.-Y.; Hemond, Harold F.; Flebbe, P.A.; Driscoll, C.T.

    1997-01-01

    Numerous freshwater ecosystems, dense concentrations of humans along the eastern seaboard, extensive forests and a history of intensive land use distinguish the New England/Mid-Atlantic Region. Human population densities are forecast to increase in portions of the region at the same time that climate is expected to be changing. Consequently, the effects of humans and climatic change are likely to affect freshwater ecosystems within the region interactively. The general climate, at present, is humid continental, and the region receives abundant precipitation. Climatic projections for a 2 ??CO2 atmosphere, however, suggest warmer and drier conditions for much of this region. Annual temperature increases ranging from 3-5??C are projected, with the greatest increases occurring in autumn or winter. According to a water balance model, the projected increase in temperature will result in greater rates of evaporation and evapotranspiration. This could cause a 21 and 31% reduction in annual stream flow in the southern and northern sections of the region, respectively, with greatest reductions occurring in autumn and winter. The amount and duration of snow cover is also projected to decrease across the region, and summer convective thunderstorms are likely to decrease in frequency but increase in intensity. The dual effects of climate change and direct anthropogenic stress will most likely alter hydrological and biogeochemical processes, and, hence, the floral and faunal communities of the region's freshwater ecosystems. For example, the projected increase in evapotranspiration and evaporation could eliminate most bog ecosystems, and increases in water temperature may increase bioaccumulation, and possibly biomagnification, of organic and inorganic contaminants. Not all change may be adverse. For example, a decrease in runoff may reduce the intensity of ongoing estuarine eutrophication, and acidification of aquatic habitats during the spring snowmelt period may be

  16. Methanethiol abundance in high-temperature hydrothermal fluids from the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Reeves, E.; Seewald, J. S.; Saccocia, P.; van der Meer, M.

    2008-12-01

    The formation of aqueous organic sulfur compounds in hydrothermal systems remains poorly constrained, despite their potential significance in 'prebiotic' chemistry and the origin of life. The simplest - methanethiol (CH3SH) - has been implicated as a critical abiogenic precursor to the establishment of primitive microbial metabolism in early Earth hydrothermal settings. It also represents a readily-utilized substrate for microbial sulfate-reducing communities and a potential intermediate species in abiotic CH4 formation. To assess the abundance of CH3SH and factors regulating its stability under hydrothermal conditions we measured CH3SH concentrations in a suite of hydrothermal fluids collected from the Rainbow, Lucky Strike, TAG and Lost City hydrothermal sites located on the Mid-Atlantic Ridge. Fluids were collected using isobaric gas-tight samplers and analyzed for CH3SH by shipboard purge-and-trap gas chromatography. Measured concentrations at Rainbow (1.2 -- 223nM), Lucky Strike (1.1 -- 26nM), TAG (8.5 -- 11nM) and Lost City (1.6 -- 3.0nM) are all substantially lower than predicted for thermodynamic equilibrium with CO2, H2 and H2S at measured vent conditions. The highest concentrations (91 -- 223nM), however, were observed at Rainbow in intermediate temperature (128 -- 175°C) H2-rich fluids that may have undergone conductive cooling. Increased concentrations with decreasing temperature is consistent with the thermodynamic drive for the formation from CO2, suggesting a possible abiotic origin for CH3SH in some fluids. Substantially lower concentrations in the low temperature fluids at Lost City are consistent with the extremely low levels of CO2 and H2S in these fluids. Other possible sources of CH3SH to vent fluids must be considered, however, and include thermal alteration of biomass present in low-temperature environments and microbial consortia that produce CH3SH as a byproduct of anaerobic methane oxidation. Current models for the emergence of primordial

  17. Quality of dissolved organic matter (DOM) in watershed compartments for a forested mid-Atlantic watershed

    NASA Astrophysics Data System (ADS)

    Singh, S.; Inamdar, S. P.; Finger, N.; Mitchell, M. J.; Levia, D. F.; Scott, D.; Bais, H.

    2010-12-01

    Catchment exports of dissolved organic matter (DOM) in streamflow can be influenced by multiple sources, which, may vary with hydrologic conditions or seasons. Thus, understanding the concentrations and quality of DOM for potential watershed sources is critical to assessing the dynamics of DOM. We investigated the quality of DOM across various watershed sources in a 12 ha forested watershed located in the Piedmont region of the mid-Atlantic USA. Sampling was performed over a two-year time period (2008-2009) and included: rainfall, throughfall, litter-leachate, soil water, riparian and wetland waters, seeps, stream runoff, and shallow and deep groundwaters. DOM constituents were characterized using ultraviolet (UV) absorption and PARAFAC modeling of fluorescence excitation emission matrices (EEMs). Specific indices that were used include: UV absorption coefficient at 254nm (a254), specific UV absorbance at 254nm (SUVA254), spectral slope ratio (SR), humification index (HIX), fluorescence index (FI), biological index (BIX), and percent humic-like and protein-like components. Our results indicated that of all the watershed DOM sources litter-leachate had the highest aromatic (high values of a254, SUVA, % C5) and humic (high HIX) content. Aromatic and humic content of DOM then decreased with soil depth with lowest values for deep groundwaters and seeps. In addition, the SR index indicated a decrease in molecular weight of DOM with soil depth. Taken together, these indices suggest that the aromatic and high molecular weight fractions of DOM were preferentially removed by sorption as runoff water percolated through the soil profile. While throughfall was less aromatic than litter-leachate, it was more aromatic than the other watershed compartments. The aromatic and humic content of soil and stream water was intermediate between litter-leachate and deep groundwaters. In contrast to the trend in aromatic DOM, the % of protein-like DOM component increased with soil depth

  18. Structure and development of an axial volcanic ridge: Mid-Atlantic Ridge, 45°N

    NASA Astrophysics Data System (ADS)

    Searle, R. C.; Murton, B. J.; Achenbach, K.; LeBas, T.; Tivey, M.; Yeo, I.; Cormier, M. H.; Carlut, J.; Ferreira, P.; Mallows, C.; Morris, K.; Schroth, N.; van Calsteren, P.; Waters, C.

    2010-10-01

    We describe the most comprehensive and detailed high resolution survey of an axial volcanic ridge (AVR) ever conducted, at 45°N on the Mid-Atlantic Ridge. We use 3 m resolution sidescan sonar, deep-towed magnetic field measurements, video observations from eleven ROV dives, and two very-high-resolution bathymetry and magnetic surveys. The most recently active AVR has high topographic relief, high acoustic backscatter, high crustal magnetization and little faulting. It is sharp-crested, 25 × 4 km in extent and 500 m high, and is covered by approximately 8000 volcanic "hummocks" whose detailed nature is revealed for the first time. Each is an individual volcano ≤ 450 m in diameter and ≤ 200 m high, ranging from steep-sided (45°) cones to low domes. Many have suffered significant flank collapse. Hummocks tend to align in rows parallel to the AVR axis, parallel to its NE-trending spurs or, on its lower flanks, sub-normal to the AVR trend. These latter are spaced 1-2 km apart and comprise 1-2 km-long rows of single volcanoes. We infer that their emplacement is controlled by down-flank magma transport, possibly via lava tubes. The AVR contains only one large flat-topped seamount. The flanking median valley floor consists of either older hummocky volcanic terrain or flat-lying, mostly sediment-covered lavas. These typically have low-relief lobate surfaces, inflation and collapse structures, and occasional lava tubes and tumuli. The AVR displays open fissures, mostly along its crest. There is direct evidence for only a few small faults on the AVR, though steep, outward-facing slopes draped by elongate pillows may be small normal faults covered by lava. The surrounding median valley floor is heavily fissured. Normal faults cut it and an older AVR, the latter displaying significant outward facing faults. High crustal magnetization, an approximate proxy for crustal age within the Brunhes, is confined to the active AVR. Magnetic palaeointensity measurements are

  19. Sea-level in the U.S. mid-Atlantic coast during the Common Era

    NASA Astrophysics Data System (ADS)

    Shaw, Timothy; García-Artola, Ane; Engelhart, Simon; Kemp, Andrew; Cahill, Niamh; Nikitina, Daria; Corbett, Reide; Brain, Matthew; Vane, Christopher; Walker, Jennifer; Pilarczyk, Jessica; Clear, Jennifer; Horton, Benjamin

    2016-04-01

    Understanding of Common Era sea-level change is fragmentary compared to understanding of temperature variability, for which several global syntheses have been generated. This limitation prevents accurate assessment of the Common Era relationship between temperature and global mean sea level (GMSL), including the sea-level response to climate phases such as the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). Previous records of relative sea-level (RSL) change along the U.S. Atlantic coast during the Common Era have revealed spatial and temporal variability that reflects differences in the static-equilibrium effects of land ice changes and/or to ocean dynamic effects. Here we present two new RSL records spanning the Common Era from saltmarsh sites in the Delaware Bay and Chesapeake Bay. Motivation for this work stems from discrepancies in the timing and magnitude of sea-level changes for the mid-Atlantic coast. This region also experiences some of the highest rates of 20th century RSL change (up to ~5 mm/yr) along the U.S. Atlantic Coast. At Delaware Bay and Chesapeake Bay, extensive stratigraphic surveys revealed thick sequences of salt-marsh peat ideally suited to proxy-based RSL reconstructions utilizing foraminifera. Estimates of paleo marsh elevation were provided through contemporary training sets incorporating modern analogues from the full range of intertidal environments and subtracted from surveyed altitudes to provide RSL trends. Temporal constraints on sea-level changes were incorporated into a Bayesian framework using a composite chronology composed of AMS radiocarbon dating, short-lived radionuclides, regional pollution histories and pollen chronohorizons documenting land clearance events. The reconstructions showed a similar pre-instrumental RSL rise of ~1.1 - 1.6 mm/yr in Delaware Bay and Chesapeake Bay, respectively. The rate of RSL rise in both regions during the past ~130 years coincides with the increased rate observed in instrumental

  20. Comparison of Nitrogen Cycling Between Old Growth Forests and Secondary Forests in the U.S. Mid-Atlantic

    NASA Astrophysics Data System (ADS)

    Walker, R. H.; Epstein, H. E.; McGarvey, J.; Thompson, J.; Mills, A. L.

    2014-12-01

    Throughout the eastern United States, forests are experiencing regrowth, and the sequestration of carbon (C) associated with this regrowth makes these forests a key component of greenhouse gas mitigation strategies (Albani et al., 2006). Through production and decomposition of plant biomass, the C and nitrogen (N) cycles are closely coupled, suggesting that N has a major impact on the cycling of C in N-limited Mid-Atlantic forest systems. The majority of C and N in a temperate forest system is located in the soil organic matter (Templer et al., 2012), so understanding soil N is important for estimating the potential for C sequestration in soils as Mid-Atlantic forests mature (Knicker, 2010). Due to the scarcity of old growth forest stands in the region, previous empirical studies of Mid-Atlantic forests in the old growth stage of succession are limited. I sampled soil C and N in twenty-five remnant old growth forests and matched secondary stands in the Mid-Atlantic to identify differences in soil organic C and N mass and concentrations of nitrate and ammonium. No significant differences were observed between the old growth and secondary growth concentrations of inorganic N species, N fraction, and C:N ratio. Rather, secondary growth values for these variables were found to have significant, positive linear relationships with old growth values, indicating that biotic and abiotic factors varying on a regional scale are driving variability seen in these N characteristics. Further, this suggests that as forest stands reach approximately 75 years in age, these N characteristics are largely established and not likely to change significantly as stands enter the old growth successional stage. Both N fraction and O-horizon depth were shown to have significant negative correlations with old growth stand age. These results indicate that old growth forest stands have a more efficient microbial decomposer community, which could have significant implications for both soil N and

  1. Sociocultural dimensions of supply and demand for natural aggregate; examples from the Mid-Atlantic region, United States

    USGS Publications Warehouse

    Robinson, Gilpin R., Jr.; Brown, William M.

    2002-01-01

    The United States uses large quantities of natural aggregate to build and maintain a continuously expanding infrastructure. In recent years, per capita demand for aggregate in the United States has grown to about 9.7 metric tons (10.7 tons) per person per year. Over the next 25 years, the aggregate industry expects to mine quantities equivalent to all aggregate mined in the United States over the past 100 years. The issues surrounding supply and demand for aggregate in the mid-Atlantic states of Maryland, Pennsylvania, Virginia, and West Virginia illustrate competing requirements for industrial minerals and many simultaneous social and environmental objectives.

  2. Simulation of the 1979 spring bloom in the Mid-Atlantic Bight - A coupled physical/biological/optical model

    NASA Technical Reports Server (NTRS)

    Gregg, Watson W.; Walsh, John J.

    1992-01-01

    A coupled physical/biological/optical model is developed for studies of phytoplankton variability in the spring 1979 Mid-Atlantic Bight, as observed by CZCS imagery. The model incorporates advection, mixing, sinking, growth as a function of light, temperature, nutrient availability, and death as a function of ingestion. It produced chlorophyll concentrations within the first attenuated depth within 1 standard deviation of CZCS imagery on large scale. The primary production estimates obtained using this model were within reasonable agreement with those measured in situ.

  3. Nested rain cell contour statistics derived from radar measurements in the mid-Atlantic coast of the United States

    NASA Technical Reports Server (NTRS)

    Goldhirsh, Julius; Musiani, Bert H.

    1991-01-01

    During a period spanning more than 5 years, a series of low elevation rain radar measurements encompassing 17 rain days were systematically executed in the mid-Atlantic coast of the United States. Drop size distribution measurements with a nearby disdrometer were also acquired during the same rain days. The drop size data were utilized to convert the radar reflectivity factors to estimated rain rates for the respective rain days of operation. Applying developed algorithms to the radar and disdrometer data, 'core' values of rain intensities and nested families of rain rate isopleths enveloping them were identified and their equi-circle diameters were statistically analyzed.

  4. Finescale parameterizations of energy dissipation in a region of strong internal tides and sheared flow, the Lucky-Strike segment of the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Pasquet, Simon; Bouruet-Aubertot, Pascale; Reverdin, Gilles; Turnherr, Andreas; Laurent, Lou St.

    2016-06-01

    The relevance of finescale parameterizations of dissipation rate of turbulent kinetic energy is addressed using finescale and microstructure measurements collected in the Lucky Strike segment of the Mid-Atlantic Ridge (MAR). There, high amplitude internal tides and a strongly sheared mean flow sustain a high level of dissipation rate and turbulent mixing. Two sets of parameterizations are considered: the first ones (Gregg, 1989; Kunze et al., 2006) were derived to estimate dissipation rate of turbulent kinetic energy induced by internal wave breaking, while the second one aimed to estimate dissipation induced by shear instability of a strongly sheared mean flow and is a function of the Richardson number (Kunze et al., 1990; Polzin, 1996). The latter parameterization has low skill in reproducing the observed dissipation rate when shear unstable events are resolved presumably because there is no scale separation between the duration of unstable events and the inverse growth rate of unstable billows. Instead GM based parameterizations were found to be relevant although slight biases were observed. Part of these biases result from the small value of the upper vertical wavenumber integration limit in the computation of shear variance in Kunze et al. (2006) parameterization that does not take into account internal wave signal of high vertical wavenumbers. We showed that significant improvement is obtained when the upper integration limit is set using a signal to noise ratio criterion and that the spatial structure of dissipation rates is reproduced with this parameterization.

  5. Widespread active detachment faulting and core complex formation near 13 degrees N on the Mid-Atlantic Ridge.

    PubMed

    Smith, Deborah K; Cann, Johnson R; Escartín, Javier

    2006-07-27

    Oceanic core complexes are massifs in which lower-crustal and upper-mantle rocks are exposed at the sea floor. They form at mid-ocean ridges through slip on detachment faults rooted below the spreading axis. To date, most studies of core complexes have been based on isolated inactive massifs that have spread away from ridge axes. Here we present a survey of the Mid-Atlantic Ridge near 13 degrees N containing a segment in which a number of linked detachment faults extend for 75 km along one flank of the spreading axis. The detachment faults are apparently all currently active and at various stages of development. A field of extinct core complexes extends away from the axis for at least 100 km. Our observations reveal the topographic characteristics of actively forming core complexes and their evolution from initiation within the axial valley floor to maturity and eventual inactivity. Within the surrounding region there is a strong correlation between detachment fault morphology at the ridge axis and high rates of hydroacoustically recorded earthquake seismicity. Preliminary examination of seismicity and seafloor morphology farther north along the Mid-Atlantic Ridge suggests that active detachment faulting is occurring in many segments and that detachment faulting is more important in the generation of ocean crust at this slow-spreading ridge than previously suspected. PMID:16871215

  6. A watershed-based method for environmental vulnerability assessment with a case study of the Mid-Atlantic region

    SciTech Connect

    Tran, Liem T.; O'Neill, Robert V.; Smith, Elizabeth R.

    2012-04-15

    The paper presents a method for environmental vulnerability assessment with a case study of the Mid-Atlantic region. The method is based on the concept of 'self-/peer-appraisal' of a watershed in term of vulnerability. The self-/peer-appraisal process is facilitated by two separate linear optimization programs. The analysis provided insights on the environmental conditions, in general, and the relative vulnerability pattern, in particular, of the Mid-Atlantic region. The suggested method offers a simple but effective and objective way to perform a regional environmental vulnerability assessment. Consequently the method can be used in various steps in environmental assessment and planning. - Highlights: Black-Right-Pointing-Pointer We present a method for regional environmental vulnerability assessment. Black-Right-Pointing-Pointer It is based on the self-/peer-appraisal concept in term of vulnerability. Black-Right-Pointing-Pointer The analysis is facilitated by two separate linear optimization programs. Black-Right-Pointing-Pointer The method provides insights on the regional relative vulnerability pattern.

  7. Investigation of extractable organic compounds in deep-sea hydrothermal vent fluids along the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    McCollom, Thomas M.; Seewald, Jeffrey S.; German, Christopher R.

    2015-05-01

    The possibility that deep-sea hydrothermal vents may contain organic compounds produced by abiotic synthesis or by microbial communities living deep beneath the surface has led to numerous studies of the organic composition of vent fluids. Most of these studies have focused on methane and other light hydrocarbons, while the possible occurrence of more complex organic compounds in the fluids has remained largely unstudied. To address this issue, the presence of higher molecular weight organic compounds in deep-sea hydrothermal fluids was assessed at three sites along the Mid-Atlantic Ridge that span a range of temperatures (51 to >360 °C), fluid compositions, and host-rock lithologies (mafic to ultramafic). Samples were obtained at several sites within the Lucky Strike, Rainbow, and Lost City hydrothermal fields. Three methods were employed to extract organic compounds for analysis, including liquid:liquid extraction, cold trapping on the walls of a coil of titanium tubing, and pumping fluids through cartridges filled with solid phase extraction (SPE) sorbents. The only samples to consistently yield high amounts of extractable organic compounds were the warm (51-91 °C), highly alkaline fluids from Lost City, which contained elevated concentrations of C8, C10, and C12n-alkanoic acids and, in some cases, trithiolane, hexadecanol, squalene, and cholesterol. Collectively, the C8-C12 acids can account for about 15% of the total dissolved organic carbon in the Lost City fluids. The even-carbon-number predominance of the alkanoic acids indicates a biological origin, but it is unclear whether these compounds are derived from microbial activity occurring within the hydrothermal chimney proximal to the site of fluid discharge or are transported from deeper within the system. Hydrothermal fluids from the Lucky Strike and Rainbow fields were characterized by an overall scarcity of extractable dissolved organic compounds. Trace amounts of aromatic hydrocarbons including

  8. Ground-water vulnerability to nitrate contamination at multiple thresholds in the mid-Atlantic region using spatial probability models

    USGS Publications Warehouse

    Greene, Earl A.; LaMotte, Andrew E.; Cullinan, Kerri-Ann

    2005-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency?s Regional Vulnerability Assessment Program, has developed a set of statistical tools to support regional-scale, ground-water quality and vulnerability assessments. The Regional Vulnerability Assessment Program?s goals are to develop and demonstrate approaches to comprehensive, regional-scale assessments that effectively inform managers and decision-makers as to the magnitude, extent, distribution, and uncertainty of current and anticipated environmental risks. The U.S. Geological Survey is developing and exploring the use of statistical probability models to characterize the relation between ground-water quality and geographic factors in the Mid-Atlantic Region. Available water-quality data obtained from U.S. Geological Survey National Water-Quality Assessment Program studies conducted in the Mid-Atlantic Region were used in association with geographic data (land cover, geology, soils, and others) to develop logistic-regression equations that use explanatory variables to predict the presence of a selected water-quality parameter exceeding a specified management concentration threshold. The resulting logistic-regression equations were transformed to determine the probability, P(X), of a water-quality parameter exceeding a specified management threshold. Additional statistical procedures modified by the U.S. Geological Survey were used to compare the observed values to model-predicted values at each sample point. In addition, procedures to evaluate the confidence of the model predictions and estimate the uncertainty of the probability value were developed and applied. The resulting logistic-regression models were applied to the Mid-Atlantic Region to predict the spatial probability of nitrate concentrations exceeding specified management thresholds. These thresholds are usually set or established by regulators or managers at National or local levels. At management thresholds of

  9. Contrasted Origins For Gabbroic Cumulates Along The Mid-Atlantic Ridge.

    NASA Astrophysics Data System (ADS)

    Nonnotte, P.; Benoit, M.; Ceuleneer, G.

    2005-12-01

    Gabbroic cumulates sampled along mid-ocean ridges are classically viewed as fractional crystallization products of primitive mid-ocean-ridge basalts (MORB) in shallow axial magma chambers. Recent observations of deep horizons of the ocean crust have shown that, in slow spreading environments, crustal building proceeds by repeated injections of modest amounts of variously evolved melt batches. Such a discontinuous character of magma emplacement favors the development of complex petrogenetic evolutions triggered by the migration of various types of melts and fluids into formerly crystallized - or still crystallizing - gabbroic cumulates and into residual peridotite. In some occurrences, however, gabbros are clearly not issued from fractional crystallization of MORB-like melts. In order to better constrain the origin of various kinds of gabbronorites emplaced along the Mid-Atlantic Ridge (MAR), we performed a geochemical study (trace elements and Sr-Nd isotopes) of clinopyroxene (cpx) separates leached with a severe analytical protocol designed to remove the geochemical effects of post-crystallization water rock interaction. We focus on two sites: MAR off the FAMOUS area (DSDP Site 334) and MAR on both sides of the 15°20 N fracture zone (MODE98-Leg1 cruise). Cumulates sampled at DSDP Site 334 are orthopyroxene-rich gabbronorites which call for parent melts richer in SiO2, more "andesitic", than MORB at a given MgO content. They also show an extreme depletion in most incompatible major, minor and trace elements compared to MORB. We measured isotopic signatures to trace the source of the DSDP Site 334 cumulates. We find that Site 334 cpx depart from the global mantle correlation: normal MORB values for the 143Nd/144Nd ratio (0.51307-0.51315) are associated to highly radiogenic 87Sr/86Sr (0.7034-0.7067) ratios. These signatures show that the parent melts of Site 334 cumulates are issued from an ultra-depleted MORB source and that contamination with seawater occurred at

  10. Lost in Iceland? Fracture Zone Complications Along the Mid-Atlantic Plate Boundary

    NASA Astrophysics Data System (ADS)

    Brandsdóttir, B.; Einarsson, P.; Detrick, R. S.; Mayer, L.; Calder, B.; Driscoll, N.; Richter, B.

    2003-12-01

    The mid-Atlantic plate boundary breaks up into a series of segments across Iceland. Two transform zones, the South Iceland Seismic Zone (SISZ) and the Tjörnes Fracture Zone (TFZ) separate the on land rift zones from the Reykjanes Ridge (RR), and the Kolbeinsey Ridge (KR), offshore N-Iceland. Both are markedly different from fracture zones elsewhere along the plate boundary. The 80 km E-W and 10--15 km N-S SISZ is made up of more than 20 N-S aligned, right-lateral, strike-slip faults whereas the TFZ consists of a broad zone of deformation, roughly 150 km E-W and 75 km N-S. The over-all left-lateral transform motion within the SISZ is accommodated by bookshelf faulting whereas the right-lateral transform motion within the TFZ is incorporated within two WNW-trending seismic zones, spaced ˜40 km apart, the Grímsey Seismic Zone (GSZ) and the Húsavík-Flatey fault (HFF). Recently collected EM300 and RESON8101 multibeam bathymetric data along with CHIRP subbottom data has unveiled some tectonic details within the TFZ. The GSZ runs along the offshore extension of the Northern Volcanic Rift Zone (NVRZ) and is made up of four left-stepping, en-echelon, NS-striking rift segments akin to those on land. Large GSZ earthquakes seem to be associated with lateral strike-slip faulting along ESE-striking fault planes. Fissure swarms transecting the offshore volcanic systems have also been subjected to right-lateral transformation along the spreading direction. As the Reykjanes Peninsula, the on land extension of the RR, the GSZ bears the characteristics of an oblique rift zone. The plate boundary segments connecting to the RR and KR are thus symmetrical with respect to the plate separation vector (105° ) and orientation of individual volcanic systems. The HFF has an overall strike of N65° W and can be traced continuously along its 75--80 km length, between the Theistareykir volcanic system within the NVRZ, across the central TFZ-graben, the Skjálfandi bay, and into the largest

  11. Compositional Comparison of Iceland Rift Zones and Adjacent Portions of the Mid-Atlantic Ridge.

    NASA Astrophysics Data System (ADS)

    Kelley, D.; Barton, M.

    2007-12-01

    Iceland is a portion of the Mid-Atlantic Ridge (MAR) that has been built by anomalous crustal production throughout the 55ma spreading history of the opening of the Atlantic Ocean. The anomalously thick crust of Iceland contains the subaerial traces of the MAR which are the volcanically active rift zones. From the south, the Reykjanes Ridge (RR) continues on land as the Western Volcanic Zone (WVZ). In the north, the Northern Volcanic Zone (NVZ) traces into the sea where it offset from the Kolbeinsey Ridge (KR) by the Tjornnes Fracture Zone (TVZ). We report the results of petrologic comparison of the WVZ, the EVZ, and the NVZ of Iceland and the adjacent portions of the MAR - the RR and the KR. The EVZ, WVZ, and NVZ have been shown to have similar crustal structures with ~20 km thick crust thickening toward the hotspot in central Iceland with magma chambers located at the base of the crust and at some depth in the upper crust. Likewise, the KR and RR have melt chambers at the base of and within the crust. Melt compositions have been compared using a filtered database of 588 glass analyses from 29 localities throughout the rift zones, 57 glass analyses from the KR, and 521 glass analyses from the RR. This is the first such study carried out with such an extensive data set. Compositions are similar between the NVZ and WVZ with SiO2 wt.% of 49.0, and 48.6, MgO wt.% of 7.9, and 7.5, and FeOT wt.% of 10.9, and 11.7 respectively. The EVZ which is considered to be a propagating rift is a bit different with SiO2 wt.% of 49.4, MgO wt.% of 5.9, and FeOT wt.% of 13.8. The NVZ and WVZ have also been compared with their respectively adjacent ridge segments, the KR (SiO2 50.3 wt.%, MgO 6.9 wt.%, and FeOT 12.0 wt.%), and the RR (SiO2 50.8 wt.%, MgO 6.9 wt.%, and FeOT 12.3 wt.%). Mg#s for the NVZ and the WVZ are 0.56, and .053 respectively while the Mg# for both the KR and RR is 0.50. For further comparison, a database of 9035 glass analyses from mid-ocean ridge basalts worldwide

  12. Hydrothermal Fluxes at the Mid-Atlantic Ridge, 5°S

    NASA Astrophysics Data System (ADS)

    Mertens, C.; Walter, M.; Koehler, J.; Sueltenfuss, J.; Rhein, M.

    2011-12-01

    The growing number of known hydrothermal vent sites has lead to an increasing recognition of the quantitative importance of hydrothermally derived materials in the large scale ocean circulation due to their possible impact on the ocean carbon cycle. The basin wide spreading of primordial helium measured during the WOCE era revealed intense hydrothermal venting in the South Atlantic, but it was not until 2005 that the first vent fields were located after intense surveys along the Mid-Atlantic Ridge. Before these sur- veys no hydrothermal fields were known in the Atlantic between 12°N and the Southern Ocean, thus leaving a large gap in the biogeography of hydrothermal vent fauna. One of the newly discovered sites is located in a relatively short segment of the rift valley at 5°S. It consists of three known high temperature fields: Turtle Pits, Comfortless Cove, and Red Lion, as well as several areas were diffuse venting was found. Hydrographic measurements were carried out at the Turtle Pits vent site during three cruises: Meteor cruise 68/1 in May 2006, a cruise with the french vessel L'Atalante in January 2008, and Meteor cruise 78/2 in April/May 2009. The data collected during these cruises are vertical profiles and towed sections of temperature, salinity, and turbidity, direct velocity measurements with lowered acoustic Doppler current profilers, as well as water samples for Helium isotope analysis. The hydrography at the vent sites is largely determined by the location of the sites in relation to the surrounding rift valley. The vents are situated in the center of the valley at a topographic sill. The water column plumes of the vent fields are clearly visible by strong signals in turbidity and temperature anomalies, and show a maximum rise height of more than 200 m, which does not exceed the height of the side walls of the graben. The currents in the rift valley are predominantly northward; the difference in stratification between upstream and downstream

  13. Controls of Plume Dispersal at the Slow Spreading Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Walter, M.; Mertens, C.; Koehler, J.; Sueltenfuss, J.; Rhein, M.; Keir, R. S.; Schmale, O.; Schneider v. Deimling, J.; German, C. R.; Yoerger, D. R.; Baker, E. T.

    2011-12-01

    The slow-spreading Mid-Atlantic Ridges hosts a multitude of different types of hydrothermal systems. Here, we compare the fluxes and the plume dispersal at three high temperature sites located in very diverse settings at comparable depths (~3000m): The recently discovered sites Turtle Pits, and Nibelungen on the southern MAR, and the Logatchev field in the North Atlantic. Plume mapping for these sites on cruises between 2004 and 2009 consisted of CTD Towyo-, Yoyo,- and station work, including velocity profiling, as well as water sampling for analysis of trace gases (CH4, H2, 3He/4He) and metals; temperature measurements and fluid sampling at the vent sites were carried out with an ROV. The aim of this work is to gain a better understanding of how the setting of a vent site affects the dispersal of the particle plume, and what means can be used to infer possible locations of vent sites based on the hydrographic properties and plume observations, using high resolution bathymetric mapping and hydrographic information. The ultramafic-hosted Nibelungen site (8°18'S) consists of a single active smoking crater, along with several extinct smokers, which is located off-axis south of a non-transform offset. The setting is characterized by rugged topography, favorable for the generation of internal tides, internal wave breaking, and vertical mixing. Elevated mixing with turbulent diffusivities Kρ up to 0.1 m2 s-1, 3 to 4 orders of magnitude higher than open ocean values, was observed close to the vent site. The mixing as well as the flow field exhibited a strong tidal cycle; the plume dispersal is thus dominated by the fast and intermittent vertical exchange and characterized by small scale spatial and temporal variability. The Turtle Pits vent fields (4°48'S) are located on a sill in a north-south orientated rift valley. The site consists of three (known) high temperature fields: Turtle Pits, Comfortless Cove, and Red Lion. The particle plume is confined to the rift

  14. Anatomy of an Axial Volcanic Ridge: The Mid-Atlantic Ridge at 45°N

    NASA Astrophysics Data System (ADS)

    Achenbach, K. L.; Searle, R. C.

    2009-12-01

    Study of a single axial volcanic ridge in the Mid-Atlantic Ridge median valley at 45°N has enabled us to construct a detailed volcano-stratigraphic model and thrown new light on the structure and development of AVRs. Data sets include 50 m resolution multibeam bathymetry, comprehensive 3 m resolution deep-towed sidescan sonar, a grid of twenty-two 1.4 km-spaced lines of deep-towed magnetic field measurements, continuous video observations and 270 rock samples from eleven ROV dives, and two approximately 8 km2 areas of very-high-resolution bathymetry and magnetics. A continuous topographic ridge extends ~35 km along the segment, and strikes 010°, ~5-10° CCW of the regional ridge trend. The northernmost 10 km appears older, as attested by lower topographic relief, acoustic backscatter and crustal magnetisation and greater degree of faulting. The rest, which we infer to be most recently constructed, is 25 km long, ~ 4 km wide and ~500 m high. It has a sharp crest, and lateral spurs trending NE that we attribute to tectonic control from the right-stepping MAR axis. The recent AVR is covered by approximately 3000 small (<450 m diameter, 200 m high) circular volcanoes ranging from steep-sided (45°) cones to more rounded domes. They tend to align in rows parallel to the AVR axis, to its NE-trending spurs, or, on its lower flanks, sub-normal to the AVR trend. These latter lineaments, which are spaced 1-2 km apart, comprise short (1-2 km) rows of single cones. We infer that their emplacement is controlled by down-flank magma transport. The AVR itself contains only one volcano >450 m diameter, though about ten, all flat-topped and up to 1.2 km diameter, occur elsewhere on the median valley floor. The high-resolution surveys show all cones >70 m high suffered significant flank collapse, often with near-vertical collapse scars. The active AVR is partly flanked by hummocky volcanic terrain similar to the AVR but of lower acoustic backscatter, which we infer to be older, and

  15. Application of satellite altimetry for fisheries investigation

    NASA Astrophysics Data System (ADS)

    Sirota, A. M.; Lebedev, S. A.; Burykin, S. N.; Timokhin, E. N.; Chernyshkov, P. P.

    Satellite altimetry data provide good possibility to reveal the zones of high dynamic activity e g oceanic currents and fronts mesoscale features etc The four oceanic region were considered Irminger Sea Mid Atlantic Ridge North Atlantic Canary Upwelling Region Eastern Central Atlantic and Southeastern Pacific Both satellite altimetry data TOPEX Poseidon ERS -1 2 and in situ measurements oceanographic surveys demonstrated good correlation between these two different types of data in revealing of dynamic features at the ocean surface The main dynamic features in the regions are Sub-Polar Front and North Atlantic Current Irminger Sea and Mid Atlantic Ridge Canary Current and coastal upwelling Eastern Central Atlantic Sub-Tropical Front and South Pacific Current Southeastern Pacific Analysis of distribution abundance and biological state of various fish species revealed the links between organisms and their dynamic environmental conditions in the considered regions Variability of the distribution and abundance of rock grenadier over Mid Atlantic Ridge is closely connected to variations of Sub-Polar Front location Distribution of fishery grounds in the Irminger Sea coincides with dynamic heterogeneities at the sea surface elevation field Distribution of small pelagic fish in Canary Upwelling Region is influenced by mesoscale features of Canary Current and coastal upwelling Sub-Tropical Front meandering and eddies in Southeast Pacific influence significantly horse mackerel distribution Thus the peculiarities of dynamic features of the ocean

  16. A Comparison of Sulfur Dioxide Column Content Between Aircraft and Satellite Over the U.S. Mid-Atlantic

    NASA Astrophysics Data System (ADS)

    Hains, J. C.; Dickerson, R. R.; Doddridge, B. G.; Burrows, J. P.; Richter, A.

    2002-12-01

    Sulfur Dioxide (SO2) is a major contributor to air pollution in the mid-Atlantic region of the United States. Sources of SO2 include coal fired power plants as well as diesel engines. Fine particulate sulfate (with diameter less than 2.5 mm) formed from SO2 can cause health problems as well as decreased visibility. Reliable measurements of SO2 within the lower troposphere are needed to determine sources, test emission inventories and to evaluate federal air quality standards. Monthly averages of SO2 lower-tropospheric column content for various points in the mid-Atlantic region of the United States have been calculated from episodic aircraft measurements during the summer months of 2000 and 2001 (http://www.meto.umd.edu/~umdair/rammpp01.html). A Thermo Environmental Instruments 4 3C SO2 analyzer was used to obtain data during aircraft spiral profiles, usually made from the near-surface to an altitude in the range of 2.3 to 3.1 km. From June to August 2000, 44 columns of SO2 were calculated from aircraft profiles over 11 different locations between North Carolina and Pennsylvania. Individual column concentrations of SO2 ranged from 0.10 to 2.31 Dobson Units (DU). Monthly averaged column concentrations were made for each location and the average concentrations for 2000 ranged from 0.02 to 1.18 DU. In 2001, 149 columns of SO2 were obtained from 36 different locations for the months of May through August. The individual column concentrations ranged from 0.01 to 3.40 DU and the monthly averaged columns ranged from 0.05 to 3.40 DU. UV-visible spectra collected by the Global Ozone Monitoring Experiment (GOME) have been analyzed for SO2 by the research group at the University of Bremen in Germany (http://www.iup.physik.uni-bremen.de/gome/). The period of data collection by the University of Maryland team coincide with data collection by the University of Bremen. The monthly averages of SO2 determined from aircraft measurements are compared with measurements from the

  17. Panmixia in a Fragmented and Unstable Environment: The Hydrothermal Shrimp Rimicaris exoculata Disperses Extensively along the Mid-Atlantic Ridge

    PubMed Central

    Teixeira, Sara; Serrão, Ester A.; Arnaud-Haond, Sophie

    2012-01-01

    Dispersal plays a fundamental role in the evolution and persistence of species, and especially for species inhabiting extreme, ephemeral and highly fragmented habitats as hydrothermal vents. The Mid-Atlantic Ridge endemic shrimp species Rimicaris exoculata was studied using microsatellite markers to infer connectivity along the 7100-Km range encompassing the sampled sites. Astonishingly, no genetic differentiation was found between individuals from the different geographic origins, supporting a scenario of widespread large-scale dispersal despite the habitat distance and fragmentation. We hypothesize that delayed metamorphosis associated to temperature differences or even active directed migration dependent on physical and/or chemical stimuli could explain these results and warrant further studies on adaptation and dispersal mechanisms. PMID:22679511

  18. Chirp seismic-reflection data from the Baltimore, Washington, and Norfolk Canyons, U.S. mid-Atlantic margin

    USGS Publications Warehouse

    Obelcz, Jeffrey B.; Brothers, Daniel S.; ten Brink, Uri S.; Chaytor, Jason D.; Worley, Charles R.; Moore, Eric M.

    2014-01-01

    A large number of high-resolution geophysical surveys between Cape Hatteras and Georges Bank have been conducted by federal, state, and academic institutions since the turn of the century. A major goal of these surveys is providing a continuous view of bathymetry and shallow stratigraphy at the shelf edge in order to assess levels of geological activity during the current sea level highstand. In 2012, chirp seismic-reflection data was collected by the U.S. Geologial Survey aboard the motor vessel Tiki XIV near three United States mid-Atlantic margin submarine canyons. These data can be used to further our understanding of passive continental margin processes during the Holocene, as well as providing valuable information regarding potential submarine geohazards.

  19. Results of APL rain gauge network measurements in mid-Atlantic coast region and comparisons of distributions with CCIR models

    NASA Technical Reports Server (NTRS)

    Goldhirsh, Julius; Gebo, Norman; Rowland, John

    1988-01-01

    In this effort are described cumulative rain rate distributions for a network of nine tipping bucket rain gauge systems located in the mid-Atlantic coast region in the vicinity of the NASA Wallops Flight Facility, Wallops Island, Virginia. The rain gauges are situated within a gridded region of dimensions of 47 km east-west by 70 km north-south. Distributions are presented for the individual site measurements and the network average for the year period June 1, 1986 through May 31, 1987. A previous six year average distribution derived from measurements at one of the site locations is also presented. Comparisons are given of the network average, the CCIR (International Radio Consultative Committee) climatic zone, and the CCIR functional model distributions, the latter of which approximates a log normal at the lower rain rate and a gamma function at the higher rates.

  20. Potassium-Argon Ages and Spreading Rates on the Mid-Atlantic Ridge at 45{degrees} North.

    PubMed

    Aumento, F; Wanless, R K; Stevens, R D

    1968-09-27

    Potassium-argon dates obtained from extrusives collected on a traverse across the Mid-Atlantic Ridge at 45 degrees N are consistent with the hypothesis of ocean-floor spreading. The dates suggest a spreading rate in the range of 2.6 to 3.2 centimeters per year near the axis of the ridge; the rate agrees with that computed from fission-track dating of basalt glasses. Additional data for a basalt collected 62 kilometers west of the axis gives a spreading rate of 0.8 centimeter per year, which is similar to the rate inferred from magnetic anomaly patterns in the area. Reasons for the difference in calculated spreading rates are discussed. PMID:17831344

  1. Compositional variation of lavas from a young volcanic field on the Southern Mid-Atlantic Ridge, 8°48'S

    NASA Astrophysics Data System (ADS)

    Haase, K.; Brandl, P. A.; Melchert, B.; Hauff, F.; Garbe-Schoenberg, C.; Paulick, H.; Kokfelt, T. F.; Devey, C. W.

    2012-12-01

    Volcanic eruptions along the mid-oceanic ridge system are the most abundant signs of volcanic activity on Earth but little is known about the timescales and nature of these processes. The main parameter determining eruption frequency as well as magma composition appears to be the spreading rate of the mid-oceanic ridge. However, few observations on the scale of single lava flows exist from the slow-spreading Mid-Atlantic Ridge so far. Here we present geological observations and geochemical data for the youngest volcanic features of the so-called A2 segment (Bruguier et al., 2003, Hoernle et al., 2011) of the slow-spreading (33 mm/yr) southern Mid-Atlantic Ridge at 8°48'S. This segment has a thickened crust of about 9 km indicating increased melt production in the mantle. Side-scan sonar mapping revealed a young volcanic field with high reflectivity that was probably erupted from two volcanic fissures each of about 3 km length. Small-scale sampling of the young lava field at 8°48'S by ROV and wax corer and geochemical analyses of the volcanic glasses reveal three different compositional lava units along this about 11 km long portion of the ridge. Based on the incompatible element compositions of volcanic glasses (e.g. K/Ti, Ce/Yb) we can distinguish two lava units forming the northern and the larger southern part of the lava field covering areas of about 5 and 9 square kilometres, respectively. Basalts surrounding the lava field and from an apparently old pillow mound within the young flows are more depleted in incompatible elements than glasses from the young volcanic field. Radium disequilibria suggest that most lavas from this volcanic field have ages of 3000 to 5000 yrs whereas the older lavas surrounding the lava field are older than 8000 yrs. Faults and a thin sediment cover on many lavas support the ages and indicate that this part of the Mid-Atlantic Ridge is in a tectonic rather than in a magmatic stage. Lavas from the northern and southern ends of the

  2. Comparative morphological studies on four populations of the shrimp Rimicaris exoculata from the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Vereshchaka, A. L.

    1997-11-01

    Four populations (a total of 677 specimens) of the hydrothermal shrimp species Rimicaris exoculata from three Mid-Atlantic Ridge vent fields were studied: Broken Spur (29°N), TAG (26°N), and "14-45" (14°N). Five morphological characters were analysed: number of dorsolateral spines on telson, telative carapace width, relative abdominal length, presence of "abnormal telson", and fat content. Dependences of each character upon shrimp size were analysed. Division of the shrimp ontogenesis on the basis of general morphology is proposed. Phenotypic analysis based upon five selected characters revealed statistically significant divergence between two populations within the same vent field TAG. Probable causes of observed divergence are discussed.

  3. Drilling the Snake Pit hydrothermal sulfide deposit on the Mid-Atlantic Ridge, lat 23/sup 0/22'N

    SciTech Connect

    Detrick, R.S.; Honnorez, J.; Adamson, A.C.; Brass, G.; Gillis, K.M.; Humphris, S.E.; Mevel, C.; Meyer, P.; Petersen, N.; Rautenschlein, M.; Shibata, T.; Staudigel, H.; Yamamoto, K.

    1986-12-01

    A major high-temperature hydrothermal area has been discovered in the Mid-Atlantic Ridge rift valley about 25 km south of the Kane Fracture Zone. The vent field consists of a wide area (> 40,000 m/sup 2/) of dark hydrothermal deposits, numerous sulfide chimneys and mounds, some up to 11 m high, and high-temperature black-smoker vents. Ten shallow holes, the first ever drilled in an active submarine hydrothermal area, recovered friable, unconsolidated Fe, Cu-Fe, and Zn sulfides and several large fragments of massive sulfide (mainly chalcopyrite) from the locally thick (> 13 m) hydrothermal deposits. The vents are also associated with an unusual biological community of smaller, more mobile organisms than reported from the East Pacific Rise.

  4. An oilspill risk analysis for the Mid-Atlantic (proposed sale 76) outer continental shelf lease area

    USGS Publications Warehouse

    Samuels, W.B.; Hopkins, Dorothy

    1982-01-01

    An oilspill risk analysis was conducted for the mid-Atlantic (proposed sale 76) Outer Continental Shelf (OCS) lease area. The analysis considered: the probability of spill occurrences based on historical trends; likely movement of oil slicks based on a climatological model; and locations of environmental resources which could be vulnerable to spilled oil. The times between spill occurrence and contact with resources were estimated to aid analysts in estimating slick characteristics. Critical assumptions made for this particular analysis were (1) that oil exists in the lease area, and (2) that 0.879 billion barrels of oil will be found and produced from tracts sold in sale 76. On the basis of this resource estimate, it was calculated that 3 to 4 oilspills of 1,000 barrels or greater will occur over the 30-year production life of the proposed sale 76 lease tracts. The results also depend upon the routes and methods chosen to transport oil from 0CS platforms to shore. Given the above assumptions, the estimated probability that one or more oilspills of 1,000 barrels or larger will occur and contact land after being at sea less than 30 days is 0.36; for spills 10,000 barrels or larger, the probability is 0.22. These probabilities also reflect the following assumptions: oilspills remain intact for up to 30 days, do not weather, and are not cleaned up. It is noteworthy that over 90 percent of the risk from proposed sale 76 is due to transportation rather than production of oil. In addition, the risks from proposed sale 76 are about 1/10 to 1/15 those of existing tanker transportation of crude oil imports and refined products in the mid-Atlantic area.

  5. Anthropocene streams and base-level controls from historic dams in the unglaciated mid-Atlantic region, USA

    USGS Publications Warehouse

    Merritts, Dorothy; Walter, Robert; Rahnis, Michael; Hartranft, Jeff; Cox, Scott; Gellis, Allen; Potter, Noel; Hilgartner, William; Langland, Michael; Manion, Lauren; Lippincott, Caitlin; Siddiqui, Sauleh; Rehman, Zain; Scheid, Chris; Kratz, Laura; Shilling, Andrea; Jenschke, Matthew; Datin, Katherine; Cranmer, Elizabeth; Reed, Austin; Matuszewski, Derek; Voli, Mark; Ohlson, Erik; Neugebauer, Ali; Ahamed, Aakash; Neal, Conor; Winter, Allison; Becker, Steven

    2011-01-01

    Recently, widespread valley-bottom damming for water power was identified as a primary control on valley sedimentation in the mid-Atlantic US during the late seventeenth to early twentieth century. The timing of damming coincided with that of accelerated upland erosion during post-European settlement land-use change. In this paper, we examine the impact of local drops in base level on incision into historic reservoir sediment as thousands of ageing dams breach. Analysis of lidar and field data indicates that historic milldam building led to local base-level rises of 2-5 m (typical milldam height) and reduced valley slopes by half. Subsequent base-level fall with dam breaching led to an approximate doubling in slope, a significant base-level forcing. Case studies in forested, rural as well as agricultural and urban areas demonstrate that a breached dam can lead to stream incision, bank erosion and increased loads of suspended sediment, even with no change in land use. After dam breaching, key predictors of stream bank erosion include number of years since dam breach, proximity to a dam and dam height. One implication of this work is that conceptual models linking channel condition and sediment yield exclusively with modern upland land use are incomplete for valleys impacted by milldams. With no equivalent in the Holocene or late Pleistocene sedimentary record, modern incised stream-channel forms in the mid-Atlantic region represent a transient response to both base-level forcing and major changes in land use beginning centuries ago. Similar channel forms might also exist in other locales where historic milling was prevalent.

  6. Watershed Scale Impacts of Stormwater Green Infrastructure on Hydrology and Nutrient Fluxes in the Mid-Atlantic Region.

    NASA Astrophysics Data System (ADS)

    Jaffe, P. R.; Pennino, M. J.; McDonald, R.

    2015-12-01

    Stormwater green infrastructure (SGI), including rain gardens, detention ponds, bioswales, and green roofs, is being implemented in cities across the globe to help reduce flooding, decrease combined sewer overflows, and lessen pollutant transport to streams and rivers. Despite the increasing use of urban SGI, there is much uncertainty regarding the cumulative effects of multiple SGI projects on hydrology and water quality at the watershed scale. To assess the cumulative effects of SGI, major cities across the mid-Atlantic were selected based on availability of SGI, water quality, and stream flow data. The impact of SGI was evaluated by comparing similar watersheds, with and without SGI or by assessing how long-term changes in SGI impact hydrologic and water quality metrics over time. Most mid-Atlantic cities have a goal of achieving 10-75% SGI by 2030. Of these cites, Washington D.C. currently has the highest density of SGI (15.5%), while Philadelphia, PA and New York, NY have the lowest (0.14% and 0.28%, respectively). When comparing watersheds of similar size and percent impervious surface cover, watersheds with lower amounts of SGI, on average, show up to 40% greater annual total nitrogen and 75% greater total phosphorus loads and show flashier hydrology (as indicated by 35% greater average peak discharge, 26% more peak discharge events per year, and 21% higher peak-to-volume ratio) compared to watersheds with higher amounts of SGI. However, for cities with combined sewer systems (e.g. Washington, D.C. and Philadelphia, PA), there was no relationship between the level of combined sewer overflows (CSOs) and the amount of SGI, indicating the level of SGI may not yet be sufficient to reduce CSOs as intended. When comparing individual watersheds over time, increases in SGI show no significant effect on the long-term trends in nutrient loads or hydrologic variables, potentially being obscured by the larger effect of interannual variability.

  7. Long-term observations of bottom current and bottom sediment movement on the mid-Atlantic continental shelf

    USGS Publications Warehouse

    Butman, Bradford; Noble, Marlene A.; Folger, David W.

    1979-01-01

    Long-term in situ observations made at three locations on the mid-Atlantic continental shelf during 1975–1976 clearly show intermittent movement of bottom sediment caused by currents, waves, and other forcing mechanisms. In winter, storm-associated bottom currents greater than 30 cm s−1 resuspended and transported sediments. Net water particle excursions during storms were about 20–30 km longshelf and 5–10 km cross-shelf. Wave-induced bottom currents also resuspended sediments during periods of low mean flow. Sediment motion was observed in summer, although bottom conditions were generally tranquil. Significant changes in suspended matter concentration were observed that were only partially related to bottom currents. These changes may have been caused by biological activity or advection. Bottom currents on the mid-Atlantic region of the continental shelf were characterized by a coherent, primarily cross-shelf tidal flow of 5–10 cm s−1 and a low-frequency longshelf component of 5–20 cm s−1. The longshelf current was coherent over length scales of 100 km at tidal frequencies and for motions with periods greater than 50 hours. For these longer periods the longshelf flow was coherent with wind stress, which implies that winds were a major driving force of the longshelf current. The cross-shelf current was not coherent at stations separated by 100 km except at tidal frequencies. Packets of high-frequency internal waves were observed during stratified conditions in summer with bottom currents as large as 20 cm s−1.

  8. Anthropocene streams and base-level controls from historic dams in the unglaciated mid-Atlantic region, USA.

    PubMed

    Merritts, Dorothy; Walter, Robert; Rahnis, Michael; Hartranft, Jeff; Cox, Scott; Gellis, Allen; Potter, Noel; Hilgartner, William; Langland, Michael; Manion, Lauren; Lippincott, Caitlin; Siddiqui, Sauleh; Rehman, Zain; Scheid, Chris; Kratz, Laura; Shilling, Andrea; Jenschke, Matthew; Datin, Katherine; Cranmer, Elizabeth; Reed, Austin; Matuszewski, Derek; Voli, Mark; Ohlson, Erik; Neugebauer, Ali; Ahamed, Aakash; Neal, Conor; Winter, Allison; Becker, Steven

    2011-03-13

    Recently, widespread valley-bottom damming for water power was identified as a primary control on valley sedimentation in the mid-Atlantic US during the late seventeenth to early twentieth century. The timing of damming coincided with that of accelerated upland erosion during post-European settlement land-use change. In this paper, we examine the impact of local drops in base level on incision into historic reservoir sediment as thousands of ageing dams breach. Analysis of lidar and field data indicates that historic milldam building led to local base-level rises of 2-5 m (typical milldam height) and reduced valley slopes by half. Subsequent base-level fall with dam breaching led to an approximate doubling in slope, a significant base-level forcing. Case studies in forested, rural as well as agricultural and urban areas demonstrate that a breached dam can lead to stream incision, bank erosion and increased loads of suspended sediment, even with no change in land use. After dam breaching, key predictors of stream bank erosion include number of years since dam breach, proximity to a dam and dam height. One implication of this work is that conceptual models linking channel condition and sediment yield exclusively with modern upland land use are incomplete for valleys impacted by milldams. With no equivalent in the Holocene or late Pleistocene sedimentary record, modern incised stream-channel forms in the mid-Atlantic region represent a transient response to both base-level forcing and major changes in land use beginning centuries ago. Similar channel forms might also exist in other locales where historic milling was prevalent. PMID:21282157

  9. Reinterpretation of the Franklin "Shore" in the Mid-Atlantic bight as a paleo-shelf edge

    NASA Astrophysics Data System (ADS)

    Goff, John A.; Austin, James A.; Fulthorpe, Craig S.

    2013-06-01

    The presence of a scarp sub-parallel to, but landward of, the modern continental shelf edge is commonly used to infer a fossil shoreline preserved during the course of a sea level rise and shoreline transgression. Advances in geophysical imaging, including bathymetric data compilations and high-resolution acoustic reflection, merit a review of these scarps and their origins. We focus on the Mid-Atlantic Bight, east coast of the United States, where four siliciclastic fossil shorelines have previously been identified and are still cited as such in the literature. Two of the scarps are not in evidence in the newest compilation of bathymetry. A third, the Mid-Shelf Scarp, is of limited extent and, as established in previous studies, represents a seaward edge of delta lobes rather than a fossil shoreline. The fourth, the Franklin Scarp, is a major topographic feature that extends from Cape Hatteras to Cape Cod. However, morphologic and stratigraphic evidence leads us to conclude that, instead of a fossil shore, this scarp represents a paleo-shelf edge, likely formed during the MIS 4 lowstand (~65 ka). Both the modern shelf edge and the Franklin Scarp deepen to the north by ~50 m, while systematically maintaining a depth offset of ~40 m. This observation, which cannot be attributed to glacial isostatic processes, is enigmatic but suggests fundamental environmental controls on the depth of the clinoform rollover. Furthermore, all the major shelf-indenting canyons in the Mid-Atlantic Bight are bounded landward by the Franklin Scarp, which suggests that interfluve progradation may be a more significant mechanism for growth of these canyons than headward erosion.

  10. Identifying patterns of forest hydrologic and biogeochemical fluxes using weather map classification in a Mid-Atlantic deciduous forest

    NASA Astrophysics Data System (ADS)

    Siegert, C. M.; Levia, D. F., Jr.; Leathers, D. J.; Van Stan, J. T., II; Mitchell, M. J.

    2014-12-01

    The partitioning of precipitation within the forest canopy into throughfall and stemflow is controlled by biotic and abiotic factors, which include storm characteristics (e.g., intensity, duration, and magnitude) and canopy structural parameters. Our research uses novel applications of weather map classification to relate synoptic scale weather patterns to the surface environment. A daily synoptic calendar was developed in the Mid-Atlantic (USA) to categorize the subcanopy hydrologic and biogeochemical fluxes during storm events in an eastern deciduous forest. Synoptic classification identified 6 low pressure systems, 4 high pressure systems, 1 cold front, 3 northerly flow regimes, 3 southerly flow regimes, and 5 weak patterns across 4 seasons. The low pressure systems were commonly associated with the largest average flux-based enrichment ratios of solutes in throughfall and stemflow compared to rainfall solute concentrations. Low pressures such as the Weak Coastal Low, centered off the Mid-Atlantic coast with easterly winds over the study region, were associated with large rainfall events with moderate intensities falling over a long period of time. This combination of meteorological conditions allowed complete washoff of antecedent atmospheric deposition and maximum canopy leaching as storm systems of this magnitude were able to wet the entire canopy. The lowest flux-based enrichment ratios occurred during the passage of cold fronts and under weak southwest flow regimes, which were both characterized by moderately high rainfall amounts that occurred over short periods of time (i.e., < 0.5 days) with high intensities (i.e., > 5 mm h-1). As a result, the water from these storm systems passed through the forest canopy very quickly and with minimal contact time thus resulting in minimal enrichment of throughfall and stemflow. The distinct chemical signatures of synoptic types provide evidence that this novel application of storm classification in forest hydrology is

  11. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (Mid-Atlantic). Surf Clam

    SciTech Connect

    Fay, C.W.; Neves, R.J.; Pardue, G.B.

    1983-10-01

    The surf clam (Spisula solidissima) is a dominant clam species in the mid-Atlantic region, and contributed 71.8% of all clam meats consumed in the United States between 1970 and 1974; total landings in 1981 were 20.9 thousand metric tons (46.1 million lb). Surf clams live in the coastal zone from the Gulf of Maine to Cape Hatteras, North Carolina; they are most common in the breaker zone, but occur to depths of 70 m (230 ft). They reach sexual maturity in 2 years and spawn in the mid-Atlantic region from mid-July through mid-October, often with two spawning peaks per year. Larval stages are planktonic; upon settlement, they metamorphose into juvenile clams. Adults live buried in sandy or gravel substrates, with siphons extended above the bottom for feeding and respiration. Surf clams may live up to 25 years and reach a size of 225 mm (8.9 inches). Larvae tolerate water temperatures of 14/sup 0/ to 30/sup 0/F (57/sup 0/) to 86/sup 0/F), and salinities as low as 16 ppt. Adults tolerate 0/sup 0/ to 28/sup 0/C (32/sup 0/ to 82/sup 0/F) and 12.5 ppt salinity or higher. Depletion of dissolved oxygen in ocean bottom waters was the major cause for large-scale surf clam mortalities off New York and New Jersey over the last two decades. Sewage, sludge, and heavy metals often cause accumulation of toxic materials in surf clam meats and force closure of beds to fishing to prevent human consumption of these toxic materials. 98 references, 2 figures, 3 tables.

  12. Appendix D of the Final Report of the Mid-Atlantic Marine Wildlife Surveys, Modeling, and Data. Workshop to Establish Coordination and Communication

    SciTech Connect

    2013-07-01

    The Wind Program hosted a two-day workshop on July 24-25, 2012 with scientists and regulators engaged in marine ecological survey, modeling, and database efforts pertaining to the waters of the Mid-Atlantic region. This is the fourth appendix to the report, the presentations from the workshop.

  13. CHARACTERIZATION AND PREDICTION OF NUTRIENTS AND PESTICIDES IN BASE FLOW CONDITIONS OF FIRST ORDER STREAMS IN THE MID-ATLANTIC COASTAL PLAIN-A COLLABORATIVE EFFORT

    EPA Science Inventory

    The Landscape Indicators for Pesticides Study in Mid-Atlantic Coastal Streams (LIPS-MACS) is a collaborative research effort between the U.S. Environmental Protection Agency's Office of Research and Development and the U.S. Geological Survey's National Water Quality Assessment Pr...

  14. Sampling techniques and detection methods for developing risk assessments for root-knot nematode (Meloidogyne incognita) on lima bean (Phaseolus lunatus) in the Mid-Atlantic region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lima bean, Phaseolus lunatus, is a cornerstone crop in the Mid-Atlantic region and Meloidogyne incognita, the southern root knot nematode (RKN), causes significant yield loss. The RKN has become more pervasive as toxic nematicides have been removed from the market, and risk evaluation research is ne...

  15. What English Language Arts, Math, and Science Instructional Materials Have Districts in the Mid-Atlantic Region States Adopted? Issues & Answers. REL 2010-No. 096

    ERIC Educational Resources Information Center

    Burzichelli, Claudia; Morrill, William; Bausmith, Jennifer; Mackey, Philip E.; Magarelli, Christopher

    2010-01-01

    Despite increasing accountability requirements and a national call for transparency in public policy, Mid-Atlantic Region state education agencies indicate that they have little information about what instructional materials districts adopt. This report describes first-year results of an ongoing project to generate and share information on core…

  16. GLOBAL CHANGE RESEARCH NEWS #34: PUBLICATION OF FACT SHEET BY EPA REGION 3, "HOW WILL CLIMATE CHANGE AFFECT THE MID-ATLANTIC REGION?"

    EPA Science Inventory

    EPA's Global Change Research Program is pleased to announce the publication of a fact sheet entitled, "How Will Climate Change Affect the Mid-Atlantic Region?." This information sheet was prepared and published by EPA's Region 3 office. It summarizes key findings from the Mid-Atl...

  17. Dropout Prevention Programs in Nine Mid-Atlantic Region School Districts: Additions to a Dropout Prevention Database. Issues & Answers. REL 2011-No. 103

    ERIC Educational Resources Information Center

    Burzichelli, Claudia; Mackey, Philip E.; Bausmith, Jennifer

    2011-01-01

    The current study replicates work of Regional Educational Laboratory (REL) Northeast and Islands. It describes dropout prevention programs in nine Mid-Atlantic Region (Delaware, the District of Columbia, Maryland, New Jersey, and Pennsylvania) school districts serving communities with populations of 24,742-107,250 (as of July 2008). All nine…

  18. Dropout Prevention Programs in Nine Mid-Atlantic Region School Districts: Additions to a Dropout Prevention Database. Summary. Issues & Answers. REL 2011-No. 103

    ERIC Educational Resources Information Center

    Burzichelli, Claudia; Mackey, Philip E.; Bausmith, Jennifer

    2011-01-01

    The current study replicates work of Regional Educational Laboratory (REL) Northeast and Islands. It describes dropout prevention programs in nine Mid-Atlantic Region (Delaware, the District of Columbia, Maryland, New Jersey, and Pennsylvania) school districts serving communities with populations of 24,742-107,250 (as of July 2008). All nine…

  19. COMPARING THE STRENGTHS OF GEOGRAPHIC AND NON-GEOGRAPHIC CLASSIFICATIONS OF STREAM BENTHIC MACROINVERTEBRATES IN THE MID-ATLANTIC HIGHLANDS, USA

    EPA Science Inventory

    The US Environmental Protection Agency's (USEPA) Environmental Monitoring and Assessment Program (EMAP) sampled approximately 500 wadeable streams in the Mid-Atlantic Highlands region of the US during the late spring of 1993 to 1995 for a variety of physical, chemical and biologi...

  20. PREDICTING THE OCCURRENCE OF NUTRIENTS AND PESTICIDES DURING BASE FLOW IN STREAMS: STATUS OF MID-ATLANTIC COASTAL PLAIN AND MIDWEST CORN BELT STUDIES

    EPA Science Inventory

    Random surveys of 174 headwater streams of the Mid-Atlantic Coastal Plain (MACP) and 110 third-order streams in the Midwest Corn Belt (MCB) were conducted in 2000 and 2004, respectively in two cooperative research studies by the U.S. Environmental Protection Agency and U.S. Geolo...

  1. MULTI-RESOURCE ENVIRONMENTAL ASSESSMENTS ACROSS THE U.S. MID-ATLANTIC REGION: USE OF GIS AND THE ISSUE OF SCALE

    EPA Science Inventory

    The U.S. EPA's Mid-Atlantic Integrated Assessment (MAIA) program is focusing on preparing State of the Region Reports. Individual resource reports have been prepared for landscapes, estuaries and streams. The program is ready to begin the integration of the information on the ind...

  2. The Squishy and Stubborn Problem of Retention: A Study of a Mid Atlantic Historically Black Institution with a Land-Grant Mission

    ERIC Educational Resources Information Center

    Nyirenda, Stanley M.; Gong, Tao

    2010-01-01

    This study of a Mid Atlantic Historically Black Institution (MAHBI) examines cognitive, social, and institutional factors to identify those that are most critical in contributing to the steady decline of the rate of student retention for this institution and others with similar characteristics. Secondary source data pertaining to three cohorts…

  3. Appendix B of the Final Report of the Mid-Atlantic Marine Wildlife Surveys, Modeling, and Data. Workshop to Establish Coordination and Communication

    SciTech Connect

    2013-07-01

    The Wind Program hosted a two-day workshop on July 24-25, 2012 with scientists and regulators engaged in marine ecological survey, modeling, and database efforts pertaining to the waters of the Mid-Atlantic region. This is the second appendix to the report, the workshop participants.

  4. EVALUATION OF MACROINVERTEBRATE TRENDS IN STREAMS VULNERABLE TO ACID DEPOSITION IN THE MID-ATLANTIC HIGHLANDS REGION OF THE U.S.A.

    EPA Science Inventory

    Benthic macroinvertebrate and water chemistry samples were collected from wadeable stream sites in the Mid-Atlantic Highlands region of the U.S. during 1993-1995 and 2001 in support of USEPA's TIME (Temporally Integrated Monitoring of Ecosystems) Progam. This study was designed ...

  5. Impact of the invasive brown marmorated stink bug, Halyomorpha halys (Stal) in Mid-Atlantic tree fruit orchards in the United States: case studies of commercial management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four commercial orchards in the mid-Atlantic region of the United States were surveyed weekly in 2010 and 2011 for the presence of brown marmorated stink bug and the injury caused to both apple and peaches. Among tested sampling techniques, baited pyramid traps yielded the most brown marmorated sti...

  6. DEVELOPMENT AND EVALUATION OF A MACROINVERTEBRATE BENTHOS INTEGRITY INDEX (SBII) FOR BIOASSESSMENT OF STREAMS IN THE MID-ATLANTIC HIGHLANDS REGION

    EPA Science Inventory

    A multimetric macroinvertebrate index called the Stream Benthos Integrity Index (SBII) was developed for the Mid-Atlantic Highlands Region of the United States. The SBII was developed for assessing biological conditions of wadeable streams and was based on benthic macroinvertebr...

  7. What English Language Arts, Math, and Science Instructional Materials Have Districts in the Mid-Atlantic Region States Adopted? Summary. Issues & Answers. REL 2010-No. 096

    ERIC Educational Resources Information Center

    Burzichelli, Claudia; Morrill, William; Bausmith, Jennifer; Mackey, Philip E.; Magarelli, Christopher

    2010-01-01

    Despite increasing accountability requirements and a national call for transparency in public policy, Mid-Atlantic Region state education agencies indicate that they have little information about what instructional materials districts adopt. This report describes first-year results of an ongoing project to generate and share information on core…

  8. National Commission on Libraries and Information Science Mid-Atlantic States Regional Hearing, Philadelphia, Pennsylvania, May 21, 1975. Volume One. Scheduled Witnesses.

    ERIC Educational Resources Information Center

    National Commission on Libraries and Information Science, Washington, DC.

    This is the first of two volumes of written testimony presented to the National Commission on Libraries and Information Science (NCLIS) at its Mid-Atlantic States Regional Hearing held May 21, 1975 at Philadelphia, Pennsylvania. Statements are provided by public, academic, research, special, regional, state, and school librarians, as well as by…

  9. Draft Genome Sequence of the Deep-Sea Ascomycetous Filamentous Fungus Cadophora malorum Mo12 from the Mid-Atlantic Ridge Reveals Its Biotechnological Potential

    PubMed Central

    Rédou, Vanessa; Kumar, Abhishek; Hainaut, Matthieu; Henrissat, Bernard; Record, Eric; Barbier, Georges

    2016-01-01

    Cadophora malorum Mo12 was isolated from the Rainbow hydrothermal site on the Mid-Atlantic Ridge. We present the draft genome sequence of this filamentous fungal strain, which has high biotechnological potentials as revealed by the presence of genes encoding biotechnologically important enzymes and genes involved in the synthesis of secondary metabolites. PMID:27389260

  10. Draft Genome Sequence of the Deep-Sea Ascomycetous Filamentous Fungus Cadophora malorum Mo12 from the Mid-Atlantic Ridge Reveals Its Biotechnological Potential.

    PubMed

    Rédou, Vanessa; Kumar, Abhishek; Hainaut, Matthieu; Henrissat, Bernard; Record, Eric; Barbier, Georges; Burgaud, Gaëtan

    2016-01-01

    Cadophora malorum Mo12 was isolated from the Rainbow hydrothermal site on the Mid-Atlantic Ridge. We present the draft genome sequence of this filamentous fungal strain, which has high biotechnological potentials as revealed by the presence of genes encoding biotechnologically important enzymes and genes involved in the synthesis of secondary metabolites. PMID:27389260

  11. PREDICTING THE OCCURRENCE OF NUTRIENTS AND PESTICIDES DURING BASE FLOW IN NONTIDAL HEADWATER STREAMS OF THE MID-ATLANTIC COASTAL PLAIN

    EPA Science Inventory

    Water quality in nontidal headwater (first-order) streams of the Mid-Atlantic Coastal Plain (MACP) during base flow in the late winter and spring is related to land use, hydrogeology, and other natural or human influences in contributing watersheds.

  12. Emergency Contraceptive Pills: A 10-Year Follow-up Survey of Use and Experiences at College Health Centers in the Mid-Atlantic United States

    ERIC Educational Resources Information Center

    Miller, Laura McKeller; Sawyer, Robin G.

    2006-01-01

    The authors conducted a 10-year follow-up study using a telephone survey to investigate the availability of emergency contraceptive pills (ECPs) at college health centers in the mid-Atlantic region of the United States. They also examined related issues, such as distribution procedure, existence of a written protocol, personnel involved,…

  13. HYDROGEOLOGIC FOUNDATION IN SUPPORT OF ECOSYSTEM RESTORATION: BASE-FLOW LOADINGS OF NITRATE IN MID-ATLANTIC AGRICULTURAL WATERSHEDS (EPA/600/R-99/104)

    EPA Science Inventory

    Field evidence suggests that deep denitrification in the subsurface has the potential forremoval of nitrate from ground water. Two adjacent agricultural watersheds in the mid-Atlantic coastal plain display remarkable differences in their ground-water nitrate discharges.It is b...

  14. Common Core State Standards and Teacher Effectiveness. Q&A with Ross Wiener, Ph.D. REL Mid-Atlantic Teacher Effectiveness Webinar Series

    ERIC Educational Resources Information Center

    Regional Educational Laboratory Mid-Atlantic, 2013

    2013-01-01

    In this REL Mid-Atlantic webinar, Dr. Ross Wiener, Vice President and Executive Director of the Education and Society Program, Aspen Institute, discussed strategies for integrating the Common Core State Standards (CCSS) into teacher effectiveness systems, including ways in which the CCSS can support professional growth and inform teacher…

  15. Mapping the Spatial and Temporal Distribution of N and O Isotopes in Precipitation Nitrate Across the Northeastern and Mid-Atlantic United States

    NASA Astrophysics Data System (ADS)

    Elliott, E. M.; Kendall, C.; Harlin, K.; Butler, T.; Carlton, R.; Wankel, S.

    2004-12-01

    Atmospheric deposition of N is a universally important pathway by which ecosystems receive fixed, bioavailable N. Since the 1880s, atmospheric deposition of N has become increasingly important, as NOx emissions from fossil fuel combustion have steadily increased. In particular, the Northeastern and Mid-Atlantic U.S. receive some of the highest rates of nitrate wet deposition in the country, causing a cascade of detrimental effects. In order to effectively mediate the impacts of nitrate deposition, it is critical to understand the dynamics among NOx sources, atmospheric chemical transformations and transport, and the characteristics of the nitrate that is ultimately deposited. To address this need, this research takes advantage of recent methodological improvements, coupled with national networks (NADP, AIRMoN) of archived precipitation, to characterize N and O isotopic composition of nitrate in precipitation across the Northeastern and Mid-Atlantic U.S. We investigate the critical question of whether variations in \\delta15N and \\delta18O of nitrate wet deposition are mainly a function of atmospheric processes (e.g., seasonal variations in reaction pathways) or variable NOx source contributions (e.g., power plant emissions, vehicle exhaust). Spatial and seasonal variability of \\delta15N and \\delta18O is investigated using bimonthly archived samples from 2000. Furthermore, a high resolution record of daily precipitation from a single site is used to highlight within-season isotopic variability. Potential correlations between isotopic values and major NOx sources are explored using EPA datasets for monthly county-level emissions from two major NOx sources, electric generating units and on-road vehicles. Analysis of samples for \\Delta17O is in progress. A key concern regarding analysis of archived samples is nitrate preservation. We tested the stability of nitrate concentrations, and hence potential isotopic fractionations, by reanalyzing filtered, refrigerated

  16. Stock enhancement to address multiple recreational fisheries objectives: an integrated model applied to red drum Sciaenops ocellatus in Florida.

    PubMed

    Camp, E V; Lorenzen, K; Ahrens, R N M; Allen, M S

    2014-12-01

    An integrated socioecological model was developed to evaluate the potential for stock enhancement with hatchery fishes to achieve socioeconomic and conservation objectives in recreational fisheries. As a case study, this model was applied to the red drum Sciaenops ocellatus recreational fishery in the Tampa Bay estuary, Florida, U.S.A. The results suggest that stocking of juvenile fish larger than the size at which the strongest density dependence in mortality occurs can help increase angler satisfaction and total fishing effort (socioeconomic objectives) but are likely to result in decreases to the abundance of wild fishes (a conservation objective). Stocking of small juveniles that are susceptible to density-dependent mortality after release does not achieve socioeconomic objectives (or only at excessive cost) but still leads to a reduction of wild fish abundance. The intensity and type of socioeconomic gains depended on assumptions of dynamic angler-effort responses and importance of catch-related satisfaction, with greatest gains possible if aggregate effort is responsive to increases in abundance and satisfaction that are greatly related to catch rates. These results emphasize the view of stock enhancement, not as a panacea but rather as a management tool with inherent costs that is best applied to recreational fisheries under certain conditions. PMID:25469950

  17. Localized Deformation Beginning more than 15 km Beneath the Mid-Atlantic Ridge, 14 to 16 N

    NASA Astrophysics Data System (ADS)

    Kelemen, P.

    2003-12-01

    ODP Leg 209 drilled 19 holes at 8 sites along the Mid-Atlantic Ridge from 14° 43 to 15° N. All sites were surveyed by submersible, and chosen to be < 200 m from peridotite or dunite exposed on the seafloor; outcrops of gabbroic rock were also close to some sites. One of our primary goals was to constrain the mechanism of mantle upwelling, corner flow and exhumation of shallow mantle rocks. Drilling at Sites 1268, 1270-72, 1274 and 1275 penetrated 1075 meters, and recovered 354 m of core. At Sites 1268 and 1270-72 we recovered 25% gabbroic rocks and 75% residual mantle peridotite. Core from Site 1274 was mainly residual peridotite, while core from Site 1275 was mainly gabbroic. Most of the residual peridotites have nearly undeformed, protogranular textures. Orthopyroxenes are interstitial to olivine or even poikilitic. Rare, isolated clinopyroxene grains are also interstitial. Skeletal spinel grains have mm-scale extensions in three dimensions, with no discernable shape fabric. These textures are clearly different from porphyroclastic textures typical in ophiolites and fracture zone dredges. As described elsewhere at this meeting, impregnated peridotites contain olivine, 2 pyroxenes, plagioclase and spinel, and equilibrated at 0.54 GPa (+/-0.14 GPa, 2σ ) and 1220° C (+/-16° C, 2σ ) [Kinzler & Grove, JGR 92]. Melts entered the thermal boundary layer beneath the Mid-Atlantic Ridge at about 20 km [e.g., Sleep, JGR 75; Reid & Jackson, MGR 82; Grove et al JGR 92; Cannat JGR 96; Michael & Chase CMP 97; Braun et al., EPSL 00], and began to crystallize within impregnated peridotites and as discrete plutons intruding peridotite. Gabbroic rocks and peridotites from most sites underwent large tectonic rotations since aquiring remanent magnetization. At some sites, rotations may have exceeded 60° around near-horizontal axes parallel to the Mid-Atlantic Ridge. Such large rotations are unlikely to have been accomodated along a single fault, and instead blocks were

  18. Deep-Towed Sidescan Sonar Studies of Amagmatic Spreading Centres: the Mid-Atlantic Ridge at 13N

    NASA Astrophysics Data System (ADS)

    Mallows, C.; Searle, R. C.; Party, J. S.

    2007-12-01

    In areas of sparse magmatism, plate separation is accommodated predominately by tectonic processes, which is often observed in the form of long-lived detachment faults exhuming lower crustal rocks and mantle peridotites to the seafloor. During research cruise JC007, a number of these oceanic core complexes (OCCs) recently identified by Smith et al. (2006) along the Mid-Atlantic Ridge (MAR) were imaged using the National Oceanography Centres Towed Ocean Bottom Instrument (TOBI). Sidescan sonar data were collected across two active OCCs at 1320N and 1330N and one inactive OCC at 1350N, including the intervening regions. We made extensive use of 3-D Fledermaus visualisations during our interpretations, and will include these in our presentation. The sidescan sonar data show distinct similarities between the two active OCCs. They both appear as large domal detachment surfaces being exhumed from beneath the ridge axis that are capped by a complexly deformed central massif and volcanic ridge at the breakaway (as suggested by Smith et al, 2006). The structures extend for c.20km off axis and c.10km along axis, and the detachment faults are characterised by large-scale spreading-parallel bathymetric corrugations and fine scale striations (interpreted as streams of basalt derived from tectonic erosional screes imaged at the terminations). The hanging walls above the zones of emergence of the detachment faults exhibit faulting that appears to trend from the ridge axis (N and S of the OCC) towards the spreading direction (at the OCC). The neo-volcanic zones along the ridge axis are apparently absent opposite active OCC formation, which is likely indicative of predominately tectonic spreading. In the regions between the active OCCs, sidescan sonar imagery shows a clear neo-volcanic zone at the ridge axis, indicating robust magmatic plate separation and accretion. The extinct OCC is characterised by heavy sediment cover over a much shallower detachment surface, presumably due to

  19. Root Cause Analysis Webinar: Q&A with Roni Silverstein. REL Mid-Atlantic Webinar

    ERIC Educational Resources Information Center

    Regional Educational Laboratory Mid-Atlantic, 2014

    2014-01-01

    Root cause analysis is a powerful method schools use to analyze data to solve problems; it aims to identify and correct the root causes of problems or events, rather than simply addressing their symptoms. In this webinar, veteran practitioner, Roni Silverstein, talked about the value of this process and practical ways to use it in your school or…

  20. Classifying multi-frequency fisheries acoustic data using a robust probabilistic classification technique.

    PubMed

    Anderson, C I H; Horne, J K; Boyle, J

    2007-06-01

    A robust probabilistic classification technique, using expectation maximization of finite mixture models, is used to analyze multi-frequency fisheries acoustic data. The number of clusters is chosen using the Bayesian Information Criterion. Probabilities of membership to clusters are used to classify each sample. The utility of the technique is demonstrated using two examples: the Gulf of Alaska representing a low-diversity, well-known system; and the Mid-Atlantic Ridge, a species-rich, relatively unknown system. PMID:17552574

  1. Seasonal and spatial patterns of Penilia avirostris and three tunicate species in the southern Mid-Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Ambler, Julie W.; Kumar, Ajoy; Moisan, Tiffany A.; Aulenbach, Donielle L.; Day, Melissa C.; Dix, Stephanie A.; Winsor, Michele A.

    2013-10-01

    The cladoceran Penilia avirostris and three tunicate species, Oikopleura dioica, Dolioletta gegenbauri and Thalia democratica, form a mesozooplankton group which ingests a wide range of particles from pico- to micro- plankton, grows rapidly due to asexual reproduction, and thus can have major impacts on phytoplankton populations. These four zooplankton species were the most abundant tunicate and cladoceran species in a study where zooplankton were sampled biweekly at five stations across the inner continental shelf in the Mid-Atlantic Bight in 2005, 2006 and 2007. Vertical tows were taken at shallow stations and depth stratified vertical tows at stations >10 m. P. avirostris and O. dioica had highly predictable seasonal cycles with peak abundances in July and August. D. gegenbauri also was present during this time period if upwelling favorable winds were present, which implies cross shelf transport from source populations in slope waters and the Gulf Stream. T. democratica only appeared in pulses when southerly winds were increasing in strength. The co-occurrence P. avirostris and the tunicate species with abundant Synechococcus and heterotrophic nanoflagellates during highly stratified summer conditions provide potential connections to microbial food webs as well as grazing opportunities on event scale blooms of dinoflagellate and diatoms species present in the area.

  2. Carbon storage in old-growth forests of the Mid-Atlantic: toward better understanding the eastern forest carbon sink.

    PubMed

    McGarvey, Jennifer C; Thompson, Jonathan R; Epstein, Howard E; Shugart, Herman H

    2015-02-01

    Few old-growth stands remain in the matrix of secondary forests that dominates the eastern North American landscape. These remnant stands offer insight on the potential carbon (C) storage capacity of now-recovering secondary forests. We surveyed the remaining old-growth forests on sites characteristic of the general Mid-Atlantic United States and estimated the size of multiple components of forest C storage. Within and between old-growth stands, variability in C density is high and related to overstory tree species composition. The sites contain 219 ± 46 Mg C/ha (mean ± SD), including live and dead aboveground biomass, leaf litter, and the soil O horizon, with over 20% stored in downed wood and snags. Stands dominated by tulip poplar (Liriodendron tulipifera) store the most live biomass, while the mixed oak (Quercus spp.) stands overall store more dead wood. Total C density is 30% higher (154 Mg C/ha), and dead wood C density is 1800% higher (46 Mg C/ha) in the old-growth forests than in the surrounding younger forests (120 and 5 Mg C/ha, respectively). The high density of dead wood in old growth relative to secondary forests reflects a stark difference in historical land use and, possibly, the legacy of the local disturbance (e.g., disease) history. Our results demonstrate the potential for dead wood to maintain the sink capacity of secondary forests for many decades to come. PMID:26240851

  3. Mesophotic reef fish assemblages of the remote St. Peter and St. Paul's Archipelago, Mid-Atlantic Ridge, Brazil

    NASA Astrophysics Data System (ADS)

    Rosa, Marcos Rogerio; Alves, Aline Cristina; Medeiros, Diego Valverde; Coni, Ericka Oliveira Cavalcanti; Ferreira, Camilo Moitinho; Ferreira, Beatrice Padovani; de Souza Rosa, Ricardo; Amado-Filho, Gilberto Menezes; Pereira-Filho, Guilherme Henrique; de Moura, Rodrigo Leão; Thompson, Fabiano Lopes; Sumida, Paulo Yukio Gomes; Francini-Filho, Ronaldo Bastos

    2016-03-01

    Mesophotic reef fish assemblages (30-90 m depth) of the small and remote St. Peter and St. Paul's Archipelago (SPSPA), Mid-Atlantic Ridge, Brazil, were characterized using remotely operated vehicles. Ordination analyses identified distinct fish assemblages in the upper (30-50 m) and lower (50-90 m) mesophotic zones, the former characterized by high abundances of species that are also abundant at euphotic reefs ( Caranx lugubris, Melichthys niger, Stegastes sanctipauli and Chromis multilineata) and the latter dominated by two mesophotic specialists ( Prognathodes obliquus and Chromis enchrysura). Planktivores dominated fish assemblages, particularly in the upper mesophotic zone, possibly due to a greater availability of zooplankton coming from the colder Equatorial Undercurrent in mesophotic depths of the SPSPA. Turf algae, fleshy macroalgae and scleractinian corals dominated benthic assemblages between 30 and 40 m depth, while bryozoans, black corals and sponges dominated between 40 and 90 m depth. Canonical correspondence analysis explained 74 % of the relationship between environmental characteristics (depth, benthic cover and complexity) and structure of fish assemblages, with depth as the most important independent variable. Juveniles of Bodianus insularis and adults of P. obliquus and C. enchrysura were clearly associated with branching black corals ( Tanacetipathes spp.), suggesting that black corals play key ecological roles in lower mesophotic reefs of the SPSPA. Results from this study add to the global database about mesophotic reef ecosystems (MREs) and provide a baseline for future evaluations of possible anthropogenic and natural disturbances on MREs of the SPSPA.

  4. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (North and Mid-Atlantic): Blue mussel

    SciTech Connect

    Newell, R.I.E.

    1989-06-01

    The blue mussel, Mytilus edulis L. is a widely distributed and locally abundant bivalve mollusc in the North and Mid-Atlantic Regions. It is a valuable commercial species; regional landings in 1986 were worth nearly $4 million. It is a semi-sessile species, anchored by byssus threads to firm surfaces in littoral and sub-littoral environments at salinities ranging from 5 to 35 ppt. It is a suspension feeder, ingesting phytoplankton and detrital particles in the size range of 3--30 /mu/m. The geographical range of the species is limited by lethal water temperatures above 27/degree/C in the south and by temperatures too low for growth and reproduction in the north. Animals from the northern end of the range are stressed by temperatures above 20/degree/C, whereas those near the southern distributional limit are not severely stressed by temperatures as high as 25/degree/C. The blue mussel is diecious and oviparous. The planktotrophic larvae take about 3 weeks to develop and metamorphose. The environmental tolerances of larvae are more restricted than those of adults. The juveniles grow to approximately 1.5 mm while attached to filamentous algae before being carried by water currents to reattach to a firm substrate, often close to adult mussels. Larval and adult blue mussels are important prey items for many animals, including crabs, fishes, and birds. 95 refs., 5 figs., 2 tabs.

  5. An oilspill risk analysis of the Mid-Atlantic (Proposed Sale 49) outer continental shelf lease area

    USGS Publications Warehouse

    Slack, James Richard; Wyant, Timothy

    1978-01-01

    An oilspill risk analysis was conducted to determine the relative environmental hazards of developing oil in different regions of the mid-Atlantic Outer Continental Shelf lease area. The study analyzed the probability of spill occurrence, likely paths of the spilled oil, and locations in space and time of recreational and biological resources that are likely to be vulnerable. These results are combined to yield estimates of the overall oilspill risk associated with development of the proposed lease area. The analysis implicitly includes estimates of weathering rates and slick dispersion and an indication of the possible mitigating effects of cleanups. Assuming that economically recoverable amounts of petroleum are found in the area, the leasing of the tracts proposed for sale 49 will increase the expected number of spills by about 20-25 percent over the number expected from the existing (sale 40) leases. The probability that an object such as land will be contacted by a spill is increased by at most five percentage points. (Woodard-USGS)

  6. Diversity and Metabolic Potentials of Subsurface Crustal Microorganisms from the Western Flank of the Mid-Atlantic Ridge

    PubMed Central

    Zhang, Xinxu; Feng, Xiaoyuan; Wang, Fengping

    2016-01-01

    Deep-sea oceanic crust constitutes the largest region of the earth’s surface. Accumulating evidence suggests that unique microbial communities are supported by iron cycling processes, particularly in the young (<10 million-year old), cool (<25°C) subsurface oceanic crust. To test this hypothesis, we investigated the microbial abundance, diversity, and metabolic potentials in the sediment-buried crust from “North Pond” on western flank of the Mid-Atlantic Ridge. Three lithologic units along basement Hole U1383C were found, which typically hosted ∼104 cells cm-3 of basaltic rock, with higher cell densities occurring between 115 and 145 m below seafloor. Similar bacterial community structures, which are dominated by Gammaproteobacterial and Sphingobacterial species closely related to iron oxidizers, were detected regardless of variations in sampling depth. The metabolic potentials of the crust microbiota were assayed by metagenomic analysis of two basalt enrichments which showed similar bacterial structure with the original sample. Genes coding for energy metabolism involved in hydrocarbon degradation, dissimilatory nitrate reduction to ammonium, denitrification and hydrogen oxidation were identified. Compared with other marine environments, the metagenomes from the basalt-hosted environments were enriched in pathways for Fe3+ uptake, siderophore synthesis and uptake, and Fe transport, suggesting that iron metabolism is an important energy production and conservation mechanism in this system. Overall, we provide evidence that the North Pond crustal biosphere is dominated by unique bacterial groups with the potential for iron-related biogeochemical cycles. PMID:27047476

  7. Nitrogen Stimulates the Growth of Subsurface Basalt-associated Microorganisms at the Western Flank of the Mid-Atlantic Ridge

    PubMed Central

    Zhang, Xinxu; Fang, Jing; Bach, Wolfgang; Edwards, Katrina J.; Orcutt, Beth N.; Wang, Fengping

    2016-01-01

    Oceanic crust constitutes the largest aquifer system on Earth, and microbial activity in this environment has been inferred from various geochemical analyses. However, empirical documentation of microbial activity from subsurface basalts is still lacking, particularly in the cool (<25°C) regions of the crust, where are assumed to harbor active iron-oxidizing microbial communities. To test this hypothesis, we report the enrichment and isolation of crust-associated microorganisms from North Pond, a site of relatively young and cold basaltic basement on the western flank of the Mid-Atlantic Ridge that was sampled during Expedition 336 of the Integrated Ocean Drilling Program. Enrichment experiments with different carbon (bicarbonate, acetate, methane) and nitrogen (nitrate and ammonium) sources revealed significant cell growth (one magnitude higher cell abundance), higher intracellular DNA content, and increased Fe3+/ΣFe ratios only when nitrogen substrates were added. Furthermore, a Marinobacter strain with neutrophilic iron-oxidizing capabilities was isolated from the basalt. This work reveals that basalt-associated microorganisms at North Pond had the potential for activity and that microbial growth could be stimulated by in vitro nitrogen addition. Furthermore, iron oxidation is supported as an important process for microbial communities in subsurface basalts from young and cool ridge flank basement. PMID:27199959

  8. The impact of mantle heterogeneity on oceanic core complex formation, 12-16°N, Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Barnard, A.; Casey, J. F.; Chang, T.; Murton, B. J.

    2012-12-01

    The 12-16°N segment of the Mid-Atlantic Ridge has two fundamentally different modes of seafloor spreading: symmetric and asymmetric. The central part of this segment (~14°N) is characterized by continuous axial rift valleys flanked by normal faults with high length/displacement ratios. In contrast, crust that has spread asymmetrically within this segment features shorter fault scarp lengths, outward tilted surfaces, nodal basins, discontinuous neovolcanic zones and has a more irregular bathymetric character. Asymmetric spreading is a result of amagmatic tectonic extension and is accommodated by very-large-offset low-angle normal faults. These faults expose a complete section through the mafic crust to serpentinized mantle on the seafloor. Collectively, tectonic, magmatic and hydrothermal processes lead to the formation and character of oceanic core complexes. Dredged peridotites from this region are predominantly harzburgites. Electron microprobe analyses of accessory chromian spinel suggest at least 16 to 20% melt extraction preceded their exposure. However, it is difficult to reconcile the high melt volumes implied by the peridotite with thin, absent, and asymmetrically spreading crust. This evidence supports our prior suggestions that magma supply, and oceanic core complex formation, within these ridge segments is controlled by mantle heterogeneities. Heterogeneities may include, but are not limited to, garnet-pyroxenite sources that produce high volume melts and ultra-depleted mantle that produce little melt. Large segments of the mantle are likely receiving a free ride to the surface without significant melting in the region.

  9. Streamlining Screening to Treatment: The Hepatitis C Cascade of Care at Kaiser Permanente Mid-Atlantic States.

    PubMed

    Jonas, M Cabell; Rodriguez, Carla V; Redd, Jacquelyn; Sloane, Dana A; Winston, Bradley J; Loftus, Bernadette C

    2016-05-15

    Hepatitis C virus (HCV) screening is recommended for patients at risk and/or born during 1945-1965, but screening gaps persist. This new program screens target populations and enhances care linkage for chronically HCV-infected patients. Kaiser Permanente Mid-Atlantic States created a comprehensive HCV screening pathway, supported by a HCV care coordinator. The testing pathway includes HCV antibody (Ab), automatic HCV RNA for Ab-positive patients, coinfection and liver health tests, vibration-controlled transient elastography (VCTE), and a physician referral. A total of 11 200 patients were screened; 3.25% were HCV Ab positive, and 100% of Ab-positive patients received HCV RNA testing. Of HCV Ab-positive patients, 75.9% had chronic HCV, of which 80.8% underwent VCTE. HCV diagnosis was communicated to 94% of patients, and 70.9% had HCV documented in the electronic health record. The pathway shows promise in closing gaps, including improving HCV RNA testing, communicating diagnoses, and assessing liver fibrosis. Improved testing and linkage could increase curative treatment access. PMID:26908812

  10. The production of methane, hydrogen, and organic compounds in ultramafic-hosted hydrothermal vents of the Mid-Atlantic Ridge.

    PubMed

    Konn, C; Charlou, J L; Holm, N G; Mousis, O

    2015-05-01

    Both hydrogen and methane are consistently discharged in large quantities in hydrothermal fluids issued from ultramafic-hosted hydrothermal fields discovered along the Mid-Atlantic Ridge. Considering the vast number of these fields discovered or inferred, hydrothermal fluxes represent a significant input of H2 and CH4 to the ocean. Although there are lines of evidence of their abiogenic formation from stable C and H isotope results, laboratory experiments, and thermodynamic data, neither their origin nor the reaction pathways generating these gases have been fully constrained yet. Organic compounds detected in the fluids may also be derived from abiotic reactions. Although thermodynamics are favorable and extensive experimental work has been done on Fischer-Tropsch-type reactions, for instance, nothing is clear yet about their origin and formation mechanism from actual data. Since chemolithotrophic microbial communities commonly colonize hydrothermal vents, biogenic and thermogenic processes are likely to contribute to the production of H2, CH4, and other organic compounds. There seems to be a consensus toward a mixed origin (both sources and processes) that is consistent with the ambiguous nature of the isotopic data. But the question that remains is, to what proportions? More systematic experiments as well as integrated geochemical approaches are needed to disentangle hydrothermal geochemistry. This understanding is of prime importance considering the implications of hydrothermal H2, CH4, and organic compounds for the ocean global budget, global cycles, and the origin of life. PMID:25984920

  11. Tectonic evolution of 200 km of Mid-Atlantic Ridge over 10 million years: Interplay of volcanism and faulting

    NASA Astrophysics Data System (ADS)

    Cann, Johnson R.; Smith, Deborah K.; Escartin, Javier; Schouten, Hans

    2015-07-01

    We reconstruct the history of the mode of accretion of an area of the Mid-Atlantic Ridge south of the Kane fracture zone using bathymetric morphology. The area includes 200 km of the spreading axis and reaches to 10 Ma on either side. We distinguish three tectonic styles: (1) volcanic construction with eruption and intrusion of magma coupled with minor faulting, (2) extended terrain with abundant large-offset faults, (3) detachment faulting marked by extension on single long-lived faults. Over 40% of the seafloor is made of extended terrain and detachment faults. The area includes products of seven spreading segments. The spreading axis has had detachment faulting or extended terrain on one or both sides for 70% of the last 10 Ma. In some parts of the area, regions of detachment faulting and extended terrain lie close to segment boundaries. Regions of detachment faulting initiated at 10 Ma close to the adjacent fracture zones to the north and south, and then expanded away from them. We discuss the complex evidence from gravity, seismic surveys, and bathymetry for the role of magma supply in generating tectonic style. Overall, we conclude that input of magma at the spreading axis has a general control on the development of detachment faulting, but the relationship is not strong. Other factors may include a positive feedback that stabilizes detachment faulting at the expense of volcanic extension, perhaps through the lubrication of active detachment faults by the formation of low friction materials (talc, serpentine) on detachment fault surfaces.

  12. Cold-climate slope deposits and landscape modifications of the Mid-Atlantic Coastal Plain, Eastern USA

    USGS Publications Warehouse

    Newell, W.L.; Dejong, B.D.

    2011-01-01

    The effects of Pleistocene cold-climate geomorphology are distributed across the weathered and eroded Mid-Atlantic Coastal Plain uplands from the Wisconsinan terminal moraine south to Tidewater Virginia. Cold-climate deposits and landscape modifications are superimposed on antecedent landscapes of old, weathered Neogene upland gravels and Pleistocene marine terraces that had been built during warm periods and sea-level highstands. In New Jersey, sequences of surficial deposits define a long history of repeating climate change events. To the south across the Delmarva Peninsula and southern Maryland, most antecedent topography has been obscured by Late Pleistocene surficial deposits. These are spatially variable and are collectively described as a cold-climate alloformation. The cold-climate alloformation includes time-transgressive details of climate deterioration from at least marine isotope stage (MIS) 4 through the end of MIS 2. Some deposits and landforms within the alloformation may be as young as the Younger Dryas. Southwards along the trend of the Potomac River, these deposits and their climatic affinities become diffused. In Virginia, a continuum of erosion and surficial deposits appears to be the product of ‘normal’ temperate, climate-forced processes. The cold-climate alloformation and more temperate deposits in Virginia are being partly covered by Holocene alluvium and bay mud.

  13. Active methane venting observed at giant pockmarks along the U.S. mid-Atlantic shelf break

    NASA Astrophysics Data System (ADS)

    Newman, Kori R.; Cormier, Marie-Helene; Weissel, Jeffrey K.; Driscoll, Neal W.; Kastner, Miriam; Solomon, Evan A.; Robertson, Gretchen; Hill, Jenna C.; Singh, Hanumant; Camilli, Richard; Eustice, Ryan

    2008-03-01

    Detailed near-bottom investigation of a series of giant, kilometer scale, elongate pockmarks along the edge of the mid-Atlantic continental shelf confirms that methane is actively venting at the site. Dissolved methane concentrations, which were measured with a commercially available methane sensor (METS) designed by Franatech GmbH mounted on an Autonomous Underwater Vehicle (AUV), are as high as 100 nM. These values are well above expected background levels (1-4 nM) for the open ocean. Sediment pore water geochemistry gives further evidence of methane advection through the seafloor. Isotopically light carbon in the dissolved methane samples indicates a primarily biogenic source. The spatial distribution of the near-bottom methane anomalies (concentrations above open ocean background), combined with water column salinity and temperature vertical profiles, indicate that methane-rich water is not present across the entire width of the pockmarks, but is laterally restricted to their edges. We suggest that venting is primarily along the top of the pockmark walls with some advection and dispersion due to local currents. The highest methane concentrations observed with the METS sensor occur at a small, circular pockmark at the southern end of the study area. This observation is compatible with a scenario where the larger, elongate pockmarks evolve through coalescing smaller pockmarks.

  14. Spatial Distribution of Brown Marmorated Stink Bug (Hemiptera: Pentatomidae) Injury at Harvest in Mid-Atlantic Apple Orchards.

    PubMed

    Joseph, Shimat V; Stallings, Jonathan W; Leskey, Tracy C; Krawczyk, Greg; Polk, Dean; Butler, Bryan; Bergh, J Christopher

    2014-10-01

    Brown marmorated stink bug, Halyomorpha halys (Stål), injury to late-season apple cultivars was measured at harvest in 2011 and 2012 in commercial orchards in four mid-Atlantic states. In each orchard block, a border zone (adjacent to woods), an interior zone (near orchard center), and an intermediate zone (between border and interior zones) comprised 1-3 tree rows per zone, depending on block size. Just before commercial harvest, 10 fruit were sampled from the upper, middle, and lower third of the canopy from five trees in each zone. After 3-5 wk in cold storage, fruit were examined for external and internal injury, and severity of internal injury (number of injury sites per fruit) from H. halys. A zero-inflated negative binomial model accounted for significant variation among the orchards and showed that apples from the upper canopy of border zone trees had the highest probability of experiencing external and internal injury. A minor interaction was detected among the orchards and zones for injury prevalence and severity, but there was no evidence of an orchard showing less expected injury in the border zone compared with other zones. Adjusting for orchard-to-orchard variation, differences in injury distributions among the zones and canopies were primarily due to injury prevalence rather than expected injury severity. The implications of these results to scouting and managing H. halys in eastern apple orchards are discussed. PMID:26309274

  15. History and geochemistry of a metalliferous sediment core from the Mid-Atlantic Ridge at 26 degree N

    SciTech Connect

    Metz, S.; Trefry, J.H. ); Nelsen, T.A. )

    1988-10-01

    Fourteen thousand years of hydrothermal deposition are recorded in a metalliferous sediment core recovered from the Trans-Atlantic Geotraverse (TAG) Hydrothermal Field on the Mid-Atlantic Ridge at 26{degree}N. An estimated 26 to > 96% of the sediment at this core site is hydrothermally derived as determined from the CaCO{sub 3}, Al and Fe data. Layers of essentially pure vent precipitates contain < 3% CaCO{sub 3} and < 0.5% Al, with high concentrations of Fe (43%), Cu (4.1%), Zn (1.2%), Mn (1.1%), V (480 ppm), Pb (175 ppm), Cd (32 ppm) and Hg (3.8 ppm). Sediment accumulation rates vary from {approximately}1 to > 30 g/cm{sup 2}/1,000 y throughout the core, a function of the intensity of hydrothermal inputs. Distinct hydrothermal events are recorded at 6,000 and 8,500 y B.P. in layers containing > 90% vent-derived material. Vertical metal profiles and interelement relationships in the core result from variable deposition of oxides and sulfides, oxidation and dissolution of sulfide phases and scavenging of metals from seawater.

  16. Evidence for Methylotrophic Symbionts in a Hydrothermal Vent Mussel (Bivalvia: Mytilidae) from the Mid-Atlantic Ridge †

    PubMed Central

    Cavanaugh, Colleen M.; Wirsen, Carl O.; Jannasch, H. W.

    1992-01-01

    Symbioses between chemolithoautotrophic bacteria and the major macrofaunal species found at hydrothermal vents have been reported for numerous sites in the Pacific Ocean. We present microscopical and enzymatic evidence that methylotrophic bacteria occur as intracellular symbionts in a new species of mytilid mussel discovered at the Mid-Atlantic Ridge hydrothermal vents. Two distinct ultrastructural types of gram-negative procaryotic symbionts were observed within gill epithelial cells by transmission electron microscopy: small coccoid or rod-shaped cells and larger coccoid cells with stacked intracytoplasmic membranes typical of methane-utilizing bacteria. Methanol dehydrogenase, an enzyme diagnostic of methylotrophs, was detected in the mytilid gills, while tests for ribulose-1,5-bisphosphate carboxylase, the enzyme diagnostic of autotrophy via the Calvin cycle, were negative. Stable carbon isotope values (δ13C) of mytilid tissue (−32.7 and −32.5% for gill and foot tissues, respectively) fall within the range of values reported for Pacific vent symbioses but do not preclude the use of vent-derived methane reported to be isotopically heavy relative to biogenically produced methane. Images PMID:16348816

  17. Simulation analysis of moored fluorometer time series from the Mid-Atlantic Bight during 1987--1990

    SciTech Connect

    Walsh, J.J.

    1990-01-01

    The goal of the previous research during 1987-1990 within the DOE (Department of Energy) Shelf Edge Exchange Processes (SEEP) program in the Mid-Atlantic Bight was to understand the physical and biogeochemical processes effecting the diffusive exchange of the proxies of energy-related, by-products associated with particulate matter between estuarine, shelf, and slope waters on this continental margin. As originally envisioned in the SEEP program plan, SEEP-III would take place at Cape Hatteras to study the advective exchange of materials by a major boundary current. One problem of continuing interest is the determination of the local assimilative capacity of slope waters and sediments off the eastern seaboard of the US to lengthen the pathway between potentially harmful energy by-products and man. At basin scales, realistic specification of the lateral transport by western boundary currents of particulate matter is a necessary input to global models of carbon/nitrogen cycling. Finally, at these global scales, the generic role of continental margins in cycling greenhouse gases, e.g. CO{sub 2}, CH{sub 4}, and N{sub 2}O, is now of equal interest. This continuing research of model construction and evaluation within the SEEP program focuses on all three questions at local, regional, and basin scales. Results from SEEP-I and II are discussed as well as plans for SEEP-III. 14 figs., 3 tabs.

  18. Biogeographical distribution of Rimicaris exoculata resident gut epibiont communities along the Mid-Atlantic Ridge hydrothermal vent sites.

    PubMed

    Durand, Lucile; Roumagnac, Marie; Cueff-Gauchard, Valérie; Jan, Cyrielle; Guri, Mathieu; Tessier, Claire; Haond, Marine; Crassous, Philippe; Zbinden, Magali; Arnaud-Haond, Sophie; Cambon-Bonavita, Marie-Anne

    2015-10-01

    Rimicaris exoculata is a deep-sea hydrothermal vent shrimp whose enlarged gill chamber houses a complex trophic epibiotic community. Its gut harbours an autochthonous and distinct microbial community. This species dominates hydrothermal ecosystem megafauna along the Mid-Atlantic Ridge, regardless of contrasting geochemical conditions prevailing in them. Here, the resident gut epibiont community at four contrasted hydrothermal vent sites (Rainbow, TAG, Logatchev and Ashadze) was analysed and compiled with previous data to evaluate the possible influence of site location, using 16S rRNA surveys and microscopic observations (transmission electron microscopy, scanning electron microscopy and fluorescence in situ hybridization analyses). Filamentous epibionts inserted between the epithelial cell microvilli were observed on all examined samples. Results confirmed resident gut community affiliation to Deferribacteres, Mollicutes, Epsilonproteobacteria and to a lesser extent Gammaproteobacteria lineages. Still a single Deferribacteres phylotype was retrieved at all sites. Four Mollicutes-related operational taxonomic units were distinguished, one being only identified on Rainbow specimens. The topology of ribotype median-joining networks illustrated a community diversification possibly following demographic expansions, suggesting a more ancient evolutionary history and/or a larger effective population size at Rainbow. Finally, the gill chamber community distribution was also analysed through ribotype networks based on sequences from R. exoculata collected at the Rainbow, Snake Pit, TAG, Logatchev and Ashadze sites. Results allow the refining of hypotheses on the epibiont role and transmission pathways. PMID:26324855

  19. Free-living nematode species (Nematoda) dwelling in hydrothermal sites of the North Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Tchesunov, Alexei V.

    2015-12-01

    Morphological descriptions of seven free-living nematode species from hydrothermal sites of the Mid-Atlantic Ridge are presented. Four of them are new for science: Paracanthonchus olgae sp. n. (Chromadorida, Cyatholaimidae), Prochromadora helenae sp. n. (Chromadorida, Chromadoridae), Prochaetosoma ventriverruca sp. n. (Desmodorida, Draconematidae) and Leptolaimus hydrothermalis sp. n. (Plectida, Leptolaimidae). Two species have been previously recorded in hydrothermal habitats, and one species is recorded for the first time in such an environment. Oncholaimus scanicus (Enoplida, Oncholaimidae) was formerly known from only the type locality in non-hydrothermal shallow milieu of the Norway Sea. O. scanicus is a very abundant species in Menez Gwen, Lucky Strike and Lost City hydrothermal sites, and population of the last locality differs from other two in some morphometric characteristics. Desmodora marci (Desmodorida, Desmodoridae) was previously known from other remote deep-sea hydrothermal localities in south-western and north-eastern Pacific. Halomonhystera vandoverae (Monhysterida, Monhysteridae) was described and repeatedly found in mass in Snake Pit hydrothermal site. The whole hydrothermal nematode assemblages are featured by low diversity in comparison with either shelf or deep-sea non-hydrothermal communities. The nematode species list of the Atlantic hydrothermal vents consists of representatives of common shallow-water genera; the new species are also related to some shelf species. On the average, the hydrothermal species differ from those of slope and abyssal plains of comparable depths by larger sizes, diversity of buccal structures, presence of food content in the gut and ripe eggs in uteri.

  20. Microbial community structure of hydrothermal deposits from geochemically different vent fields along the Mid-Atlantic Ridge

    USGS Publications Warehouse

    Flores, Gilberto E.; Campbell, James H.; Kirshtein, Julie D.; Meneghin, Jennifer; Podar, Mircea; Steinberg, Joshua I.; Seewald, Jeffrey S.; Tivey, Margaret Kingston; Voytek, Mary A.; Yang, Zamin K.; Reysenbach, Anna-Louise

    2011-01-01

    To evaluate the effects of local fluid geochemistry on microbial communities associated with active hydrothermal vent deposits, we examined the archaeal and bacterial communities of 12 samples collected from two very different vent fields: the basalt-hosted Lucky Strike (37°17'N, 32°16.3'W, depth 1600-1750m) and the ultramafic-hosted Rainbow (36°13'N, 33°54.1'W, depth 2270-2330m) vent fields along the Mid-Atlantic Ridge (MAR). Using multiplexed barcoded pyrosequencing of the variable region 4 (V4) of the 16S rRNA genes, we show statistically significant differences between the archaeal and bacterial communities associated with the different vent fields. Quantitative polymerase chain reaction (qPCR) assays of the functional gene diagnostic for methanogenesis (mcrA), as well as geochemical modelling to predict pore fluid chemistries within the deposits, support the pyrosequencing observations. Collectively, these results show that the less reduced, hydrogen-poor fluids at Lucky Strike limit colonization by strict anaerobes such as methanogens, and allow for hyperthermophilic microaerophiles, like Aeropyrum. In contrast, the hydrogen-rich reducing vent fluids at the ultramafic-influenced Rainbow vent field support the prevalence of methanogens and other hydrogen-oxidizing thermophiles at this site. These results demonstrate that biogeographical patterns of hydrothermal vent microorganisms are shaped in part by large scale geological and geochemical processes.

  1. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Mid-Atlantic): Atlantic marsh fiddler

    SciTech Connect

    Grimes, B.H.; Huish, M.T.; Kerby, J.H.; Moran, D.; National Wetlands Research Center, Slidell, LA )

    1989-09-01

    The Atlantic marsh fiddler is the only endemic species of Uca in the Mid-Atlantic region. Males display a series of visual and acoustical displays during mating, with a weak waving and bleaching of the larger claw. Egg clutch size in female varies. Larvae are released in phase with nocturnal high tides. The 5 zoeal and 1 megalops stages compose much of the estuarine plankton. First and second crab stages are weak and unable to burrow. Adult lifespan is 1--1.5 years with 1--2 molts per year. Molting is temperature dependent and ceases below 20{degree}C. Crabs feed by scrubbing the preferred muddy substratum for diatoms, fungi, vascular plants, and debris, bioturbating and recycling the marsh surface. This crab is eaten regularly by estuarine birds, fish, crabs, and some mammals. This fiddler can acclimate to lower temperatures, but dies below 2-3{degree}C or above 40{degree}C. It prefers seawater, lacking freshwater tolerance. Oxygen uptake correlates with activity. Preferred habitats are muddy substrata and short smooth cordgrass. Burrow density decreases from low to high marsh. The Atlantic marsh fiddler has the highest radiation LD-50 of sympatric species of fiddler crabs. Insecticides Temefos, DDT, DDF, Aldrin, and Dieldrin, and contaminant PCB's, mercury, and cadmium reduce populations of fiddlers, some being concentrated in their tissues. 90 refs., 4 figs.

  2. High-resolution bathymetry reveals contrasting landslide activity shaping the walls of the Mid-Atlantic Ridge axial valley

    NASA Astrophysics Data System (ADS)

    Cannat, Mathilde; Mangeney, Anne; OndréAs, HéLèNe; Fouquet, Yves; Normand, Alain

    2013-04-01

    Axial valleys are found along most slow-spreading mid-ocean ridges and are one of the most prominent topographic features on Earth. In this paper, we present the first deep-tow swath bathymetry for the axial valley walls of the Mid-Atlantic Ridge. These data allow us to analyze axial valley wall morphology with a very high resolution (0.5 to 1 m compared to ≥ 50 m for shipboard multibeam bathymetry), revealing the role played by landslides. Slow-spreading ridge axial valleys also commonly expose mantle-derived serpentinized peridotites in the footwalls of large offset normal faults (detachments). In our map of the Ashadze area (lat. 13°N), ultramafic outcrops have an average slope of 18° and behave as sliding deformable rock masses, with little fragmentation. By contrast, the basaltic seafloor in the Krasnov area (lat. 16°38'N) has an average slope of 32° and the erosion of the steep basaltic rock faces leads to extensive fragmentation, forming debris with morphologies consistent with noncohesive granular flow. Comparison with laboratory experiments suggests that the repose angle for this basaltic debris is > 25°. We discuss the interplay between the normal faults that bound the axial valley and the observed mass wasting processes. We propose that, along axial valley walls where serpentinized peridotites are exposed by detachment faults, mass wasting results in average slopes ≤ 20°, even in places where the emergence angle of the detachment is larger.

  3. The relationships between volcanism, tectonism and hydrothermal activity on the Mid-Atlantic Ridge south of the equator

    NASA Astrophysics Data System (ADS)

    Devey, C. W.; German, C. R.; Haase, K. M.; Lackschewitz, K. S.; Melchert, B.; Connelly, D.; Parson, L. M.

    2009-04-01

    Using data from the complete bathymetric and side-scan (TOBI) coverage of the Mid-Atlantic Ridge 2-14 °S collected since 2004 in conjunction with the results of extensive prospecting for hydrothermal systems in this area we attempt to formulate a general model for the interplay between volcanism, tectonics and hydrothermalism on a slow-spreading ridge. The model defines three basic types of ridge morphology with specific hydrothermal characteristics: (a) A deep, tectonically-dominated rift valley where hydrothermalism is seldom associated with volcanism and much more likely confined to long-lived bounding faults (b) a shallower, segment-centre bulge where a combination of repeated magmatic activity and tectonism results in repeated, possibly temporally overlapping periods of hydrothermal activity on the ridge axis and (c) a very shallow, inflated axis beneath which temperatures in all but the uppermost crust are so high that deformation is ductile, inhibiting the formation of high-porosity deep fractures and severely depressing hydrothermal circulation. This model is used together with predicted bathymetry to provide forecasts of the best places to look for hydrothermal sites in the remaining unexplored regions of the South Atlantic

  4. Nitrogen Stimulates the Growth of Subsurface Basalt-associated Microorganisms at the Western Flank of the Mid-Atlantic Ridge.

    PubMed

    Zhang, Xinxu; Fang, Jing; Bach, Wolfgang; Edwards, Katrina J; Orcutt, Beth N; Wang, Fengping

    2016-01-01

    Oceanic crust constitutes the largest aquifer system on Earth, and microbial activity in this environment has been inferred from various geochemical analyses. However, empirical documentation of microbial activity from subsurface basalts is still lacking, particularly in the cool (<25°C) regions of the crust, where are assumed to harbor active iron-oxidizing microbial communities. To test this hypothesis, we report the enrichment and isolation of crust-associated microorganisms from North Pond, a site of relatively young and cold basaltic basement on the western flank of the Mid-Atlantic Ridge that was sampled during Expedition 336 of the Integrated Ocean Drilling Program. Enrichment experiments with different carbon (bicarbonate, acetate, methane) and nitrogen (nitrate and ammonium) sources revealed significant cell growth (one magnitude higher cell abundance), higher intracellular DNA content, and increased Fe(3+)/ΣFe ratios only when nitrogen substrates were added. Furthermore, a Marinobacter strain with neutrophilic iron-oxidizing capabilities was isolated from the basalt. This work reveals that basalt-associated microorganisms at North Pond had the potential for activity and that microbial growth could be stimulated by in vitro nitrogen addition. Furthermore, iron oxidation is supported as an important process for microbial communities in subsurface basalts from young and cool ridge flank basement. PMID:27199959

  5. Diversity and Metabolic Potentials of Subsurface Crustal Microorganisms from the Western Flank of the Mid-Atlantic Ridge.

    PubMed

    Zhang, Xinxu; Feng, Xiaoyuan; Wang, Fengping

    2016-01-01

    Deep-sea oceanic crust constitutes the largest region of the earth's surface. Accumulating evidence suggests that unique microbial communities are supported by iron cycling processes, particularly in the young (<10 million-year old), cool (<25°C) subsurface oceanic crust. To test this hypothesis, we investigated the microbial abundance, diversity, and metabolic potentials in the sediment-buried crust from "North Pond" on western flank of the Mid-Atlantic Ridge. Three lithologic units along basement Hole U1383C were found, which typically hosted ∼10(4) cells cm(-3) of basaltic rock, with higher cell densities occurring between 115 and 145 m below seafloor. Similar bacterial community structures, which are dominated by Gammaproteobacterial and Sphingobacterial species closely related to iron oxidizers, were detected regardless of variations in sampling depth. The metabolic potentials of the crust microbiota were assayed by metagenomic analysis of two basalt enrichments which showed similar bacterial structure with the original sample. Genes coding for energy metabolism involved in hydrocarbon degradation, dissimilatory nitrate reduction to ammonium, denitrification and hydrogen oxidation were identified. Compared with other marine environments, the metagenomes from the basalt-hosted environments were enriched in pathways for Fe(3+) uptake, siderophore synthesis and uptake, and Fe transport, suggesting that iron metabolism is an important energy production and conservation mechanism in this system. Overall, we provide evidence that the North Pond crustal biosphere is dominated by unique bacterial groups with the potential for iron-related biogeochemical cycles. PMID:27047476

  6. Distinct Benthic Community Trends Driven by Particle Transport and Deposition in Mid-Atlantic Bight Canyons, NW Atlantic

    NASA Astrophysics Data System (ADS)

    Demopoulos, A. W.; Robertson, C. M.; Bourque, J. R.; Mienis, F.; Duineveld, G.; Ross, S.; Brooke, S.; Davies, A. J.

    2014-12-01

    The Mid-Atlantic Bight (MAB) is a well-studied region of the U.S. East coast continental margin, rich in submarine canyons. Baltimore and Norfolk canyons were studied during the multidisciplinary Atlantic Deepwater Canyons project through funding from BOEM, NOAA, and USGS. Sediment and water column properties were assessed in the context of canyon physical dynamics and ecosystem ecology. Sediment samples were collected by NIOZ box corer in 2012 and 2013 along canyon axes and comparative adjacent slopes at standardized depths. Sediments were analyzed for grain size, organic content, stable carbon and nitrogen isotopes, chlorophyll a, and benthic infauna. Water column properties were sampled using CTD transects, and benthic landers and moorings positioned along canyon axes. Significant differences in sediment transport regimes were found for each canyon where observed nepheloid layers corresponded to shifts in infaunal community structure. Significant community shifts were observed in stations at depths > 900m in Baltimore Canyon, coinciding with higher organic matter concentrations at depths below the nepheloid layer. In contrast, adjacent slope communities exhibited a more uniform infaunal assemblage where distinct zonation patterns by depth were observed. Preliminary data for Norfolk Canyon suggest very different sediment deposition rates in the canyon and also show clear differences between canyon and slope benthic communities. Geological processes and canyon topography coupled with organic inputs and disturbance events are clear factors in determining benthic infaunal diversity and standing stock dynamics in and around these canyons.

  7. Microbial community structure of hydrothermal deposits from geochemically different vent fields along the Mid-Atlantic Ridge

    SciTech Connect

    Flores, Gilberto E; Campbell, James H; Kirshtein, Julie D; Meneghin, Jennifer; Podar, Mircea; Steinberg, Joshua; Seewald, Jeffrey S; Tivey, Margaret Kingston; Voytek, Mary A; Reysenbach, Anna-Louise; Yang, Zamin Koo

    2011-01-01

    To evaluate the effects of local fluid geochemistry on microbial communities associated with active hydrothermal vent deposits, we examined the archaeal and bacterial communities of 12 samples collected from two very different vent fields: the basalt-hosted Lucky Strike (37 17'N, 32 16.3'W, depth 1600-1750 m) and the ultramafic-hosted Rainbow (36 13'N, 33 54.1'W, depth 2270-2330 m) vent fields along the Mid-Atlantic Ridge (MAR). Using multiplexed barcoded pyrosequencing of the variable region 4 (V4) of the 16S rRNA genes, we show statistically significant differences between the archaeal and bacterial communities associated with the different vent fields. Quantitative polymerase chain reaction (qPCR) assays of the functional gene diagnostic for methanogenesis (mcrA), as well as geochemical modelling to predict pore fluid chemistries within the deposits, support the pyrosequencing observations. Collectively, these results show that the less reduced, hydrogen-poor fluids at Lucky Strike limit colonization by strict anaerobes such as methanogens, and allow for hyperthermophilic microaerophiles, like Aeropyrum. In contrast, the hydrogen-rich reducing vent fluids at the ultramafic-influenced Rainbow vent field support the prevalence of methanogens and other hydrogen-oxidizing thermophiles at this site. These results demonstrate that biogeographical patterns of hydrothermal vent microorganisms are shaped in part by large scale geological and geochemical processes.

  8. Volcanic Glasses as Habitat for Microfossils: Evidence from the Early Paleoproterozoic Pillow Lavas of Karelia and their Modern Analogues in the Mid-Atlantic Ridge

    NASA Technical Reports Server (NTRS)

    Adtafieva, M. M.; Rozanov, A. Yu; Sharkov, E. V.; Chistyakov, A. V.; Bogina, M. M.; Hoover, R. B.

    2009-01-01

    Microbial complexes were identified in the volcanic glasses from the ancient (2.4-Ga-old basaltic pillow-lavas of Karelia) and modern (pillow lavas of Mid-Atlantic ridge) volcanic rocks. It was shown that that their microbial colonization is likely to occur by the same mechanism. Thus, well preserved pillow lavas, which occupy a spacious fields in the Archean and Early Paleoproterozoic greenstone belts, are promising object for search of the earliest traces of life on Earth.

  9. Wave refraction diagrams for the Baltimore Canyon region of the mid-Atlantic continental shelf computed by using three bottom topography approximation techniques

    NASA Technical Reports Server (NTRS)

    Poole, L. R.

    1976-01-01

    The Langley Research Center and Virginia Institute of Marine Science wave refraction computer model was applied to the Baltimore Canyon region of the mid-Atlantic continental shelf. Wave refraction diagrams for a wide range of normally expected wave periods and directions were computed by using three bottom topography approximation techniques: quadratic least squares, cubic least squares, and constrained bicubic interpolation. Mathematical or physical interpretation of certain features appearing in the computed diagrams is discussed.

  10. Crustal structure of the Mid-Atlantic Margin from the MAGIC seismic array

    NASA Astrophysics Data System (ADS)

    Benoit, M. H.; Long, M. D.; Kirby, E.; King, S. D.; Miller, S. R.

    2015-12-01

    The eastern United States continental margin has undergone two full supercontinental cycles over the last billion years. While the scars of the repeated episodes of rifting, subduction, and collision are evident in the surficial geology of the eastern United States, the deeper crust and mantle lithospheric structure of the region also was altered during this tectonism. In general, the bulk crustal structure of the eastern US has largely remained uncharacterized before the arrival of the EarthScope, other than through analysis of a handful of regional seismic arrays. We present results of receiver function stacking of seismic data recorded from the MAGIC EarthScope Flex Array, composed of 27 STS-2 broadband stations located in a linear array that spans roughly SE-NE from Richmond,VA to Fort Wayne, Indiana. The array traverses several physiographic provinces, including the Atlantic Piedmont, Blue Ridge, Appalachian Valley and Ridge, and Appalachian Plateau. Preliminary results suggest that the crustal thickness varies significantly over short lateral distances in Virginia, and that the crust within the Appalachian Valley and Ridge contains significant layering. Characterization of the crustal thickness can help address long-standing questions regarding the relative contribution of isostasy in sustaining Appalachian topography.

  11. Testing Models of Mantle Upwelling: Microstructure, Crystallography, and Seismic Anisotropy of Peridotites From 15 Degrees N, Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Achenbach, K. L.; Faul, U.; Cheadle, M.; Swapp, S.

    2005-12-01

    Owing to the scarcity of oriented mantle peridotite samples, few microstructural and crystallographic data are currently available to constrain models of mantle upwelling and deformation beneath slow-spreading ridges. Here we present quantitative data regarding the shape- and lattice-preferred orientations (SPO and LPO) of olivine and orthopyroxene in peridotites from Hole 1274A, drilled to a depth of 156 mbsf, on the western flank of the rift valley wall at 15° 39' N on the Mid-Atlantic Ridge during ODP Leg 209. With as little as 50% alteration in places, our samples are the freshest peridotites recovered during Leg 209. The rocks are protogranular harzburgites with 75-82% olivine, 17-22% orthopyroxene, 0.8-1.4% clinopyroxene, and 0.9-2.4% spinel, and one dunite with 96.3% olivine, 0.1% opx, 1.7% clinopyroxene, and 1.9% spinel . The samples preserve evidence of melt-rock interaction and weak lithospheric deformation, but the primary asthenospheric SPO is preserved. Olivine and orthopyroxene exhibit a weak but consistently measurable foliation; no spinel lineation is readily apparent. Crystallographic data, collected using Electron Backscatter Diffraction (EBSD), are based on measurements of as many as 1100 olivine crystals and 530 orthopyroxene crystals per sample in rocks from ten sections of core (recovered from depths ranging from 20 - 150 mbsf). Olivine crystals show a strong [010] maximum subperpendicular to foliation, with a less strongly developed [100] maximum and diffuse clusters of [001] axes roughly parallel to the foliation plane. This fabric is consistent with dislocation creep operating at ~1200° C predominantly on the olivine (010)[100] slip system. The relatively weakly developed [100] and [001] maxima may be attributed to a low strain rate, or to a component of slip in another slip system. Orthopyroxene crystals show a [001] maximum parallel to the foliation plane, with a [100] maximum subperpendicular to the foliation plane, indicative of the

  12. The Production of Methane, Hydrogen, and Organic Compounds in Ultramafic-Hosted Hydrothermal Vents of the Mid-Atlantic Ridge

    PubMed Central

    Charlou, J.L.; Holm, N.G.; Mousis, O.

    2015-01-01

    Abstract Both hydrogen and methane are consistently discharged in large quantities in hydrothermal fluids issued from ultramafic-hosted hydrothermal fields discovered along the Mid-Atlantic Ridge. Considering the vast number of these fields discovered or inferred, hydrothermal fluxes represent a significant input of H2 and CH4 to the ocean. Although there are lines of evidence of their abiogenic formation from stable C and H isotope results, laboratory experiments, and thermodynamic data, neither their origin nor the reaction pathways generating these gases have been fully constrained yet. Organic compounds detected in the fluids may also be derived from abiotic reactions. Although thermodynamics are favorable and extensive experimental work has been done on Fischer-Tropsch-type reactions, for instance, nothing is clear yet about their origin and formation mechanism from actual data. Since chemolithotrophic microbial communities commonly colonize hydrothermal vents, biogenic and thermogenic processes are likely to contribute to the production of H2, CH4, and other organic compounds. There seems to be a consensus toward a mixed origin (both sources and processes) that is consistent with the ambiguous nature of the isotopic data. But the question that remains is, to what proportions? More systematic experiments as well as integrated geochemical approaches are needed to disentangle hydrothermal geochemistry. This understanding is of prime importance considering the implications of hydrothermal H2, CH4, and organic compounds for the ocean global budget, global cycles, and the origin of life. Key Words: Hydrogen—Methane—Organics—MAR—Abiotic synthesis—Serpentinization—Ultramafic-hosted hydrothermal vents. Astrobiology 15, 381–399. PMID:25984920

  13. Evaluation of two algorithms for a network of coastal HF radars in the Mid-Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Kohut, Josh; Roarty, Hugh; Randall-Goodwin, Evan; Glenn, Scott; Lichtenwalner, C. Sage

    2012-06-01

    The National High Frequency (HF) Surface Current Mapping Radar Network is being developed as a backbone system within the U.S. Integrated Ocean Observing System. This paper focuses on the application of HF radar-derived surface current maps to U.S. Coast Guard Search and Rescue operations along the Mid-Atlantic coast of the USA. In that context, we evaluated two algorithms used to combine maps of radial currents into a single map of total vector currents. In situ data provided by seven drifter deployments and four bottom-mounted current meters were used to (1) evaluate the well-established unweighted least squares (UWLS) and the more recently adapted optimal interpolation (OI) algorithms and (2) quantify the sensitivity of the OI algorithm to varying decorrelation scales and error thresholds. Results with both algorithms were shown to depend on the location within the HF radar data footprint. The comparisons near the center of the HF radar coverage showed no significant difference between the two algorithms. The most significant distinction between the two was seen in the drifter trajectories. With these simulations, the weighting of radial velocities by distance in the OI implementation was very effective at reducing both the distance between the actual drifter and the cluster of simulated particles as well as the scale of the search area that encompasses them. In this study, the OI further reduced the already improved UWLS-based search areas by an additional factor of 2. The results also indicated that the OI output was relatively insensitive to the varying decorrelation scales and error thresholds tested.

  14. Landscape controls on the timing of spring, autumn, and growing season length in mid-Atlantic forests

    USGS Publications Warehouse

    Elmore, A.J.; Guinn, S.M.; Minsley, B.J.; Richardson, A.D.

    2012-01-01

    The timing of spring leaf development, trajectories of summer leaf area, and the timing of autumn senescence have profound impacts to the water, carbon, and energy balance of ecosystems, and are likely influenced by global climate change. Limited field-based and remote-sensing observations have suggested complex spatial patterns related to geographic features that influence climate. However, much of this variability occurs at spatial scales that inhibit a detailed understanding of even the dominant drivers. Recognizing these limitations, we used nonlinear inverse modeling of medium-resolution remote sensing data, organized by day of year, to explore the influence of climate-related landscape factors on the timing of spring and autumn leaf-area trajectories in mid-Atlantic, USA forests. We also examined the extent to which declining summer greenness (greendown) degrades the precision and accuracy of observations of autumn offset of greenness. Of the dominant drivers of landscape phenology, elevation was the strongest, explaining up to 70% of the spatial variation in the onset of greenness. Urban land cover was second in importance, influencing spring onset and autumn offset to a distance of 32 km from large cities. Distance to tidal water also influenced phenological timing, but only within ~5 km of shorelines. Additionally, we observed that (i) growing season length unexpectedly increases with increasing elevation at elevations below 275 m; (ii) along gradients in urban land cover, timing of autumn offset has a stronger effect on growing season length than does timing of spring onset; and (iii) summer greendown introduces bias and uncertainty into observations of the autumn offset of greenness. These results demonstrate the power of medium grain analyses of landscape-scale phenology for understanding environmental controls on growing season length, and predicting how these might be affected by climate change.

  15. Geomorphic characterization of four shelf-sourced submarine canyons along the U.S. Mid-Atlantic continental margin

    USGS Publications Warehouse

    Obelcz, Jeffrey; Brothers, Daniel S.; Chaytor, Jason D.; ten Brink, Uri S.; Ross, Steve W.; Brooke, Sandra

    2013-01-01

    Shelf-sourced submarine canyons are common features of continental margins and are fundamental to deep-sea sedimentary systems. Despite their geomorphic and geologic significance, relatively few passive margin shelf-breaching canyons worldwide have been mapped using modern geophysical methods. Between 2007 and 2012 a series of geophysical surveys was conducted across four major canyons of the US Mid-Atlantic margin: Wilmington, Baltimore, Washington, and Norfolk canyons. More than 5700 km2 of high-resolution multibeam bathymetry and 890 line-km of sub-bottom CHIRP profiles were collected along the outer shelf and uppermost slope (depths of 80-1200 m). The data allowed us to compare and contrast the fine-scale morphology of each canyon system. The canyons have marked differences in the morphology and orientation of canyon heads, steepness and density of sidewall gullies, and the character of the continental shelf surrounding canyon rims. Down-canyon axial profiles for Washington, Baltimore and Wilmington canyons have linear shapes, and each canyon thalweg exhibits morphological evidence for recent, relatively small-scale sediment transport. For example, Washington Canyon displays extremely steep wall gradients and contains ~100 m wide, 5–10 m deep, v-shaped incisions down the canyon axis, suggesting modern or recent sediment transport. In contrast, the convex axial thalweg profile, the absence of thalweg incision, and evidence for sediment infilling at the canyon head, suggest that depositional processes strongly influence Norfolk Canyon during the current sea-level high-stand. The north walls of Wilmington, Washington and Norfolk canyons are steeper than the south walls due to differential erosion, though the underlying cause for this asymmetry is not clear. Furthermore, we speculate that most of the geomorphic features observed within the canyons (e.g., terraces, tributary canyons, gullies, and hanging valleys) were formed during the Pleistocene, and show only

  16. On the mass and salt budgets for a region of the continental shelf in the southern Mid-Atlantic Bight

    SciTech Connect

    Kim, Yoo Yin; Weatherly, Georges L.; Pietrafesa, Leonard J.

    2001-12-01

    Two field studies were conducted across and along the continental shelf, one from February to May 1996 (deployment 1) and the other from July to October 1996 (deployment 2), in part to determine the mass and salt budgets of shelf water from south of Cape Henry to north of Cape Hatteras, the southernmost portion of the Mid-Atlantic Bight. The temporal means of current meter records indicated that most of the water enters the region across its northern boundary near the shelf break as part of a southward, alongshore current and exits the southeast corner as a southeastward flowing current. Estimates of the volume transports indicated that not all the transport across the northern boundary was accounted for by transport across the southern boundary, and that the remainder occurred as a broad, diffusive flow across the eastern boundary at the shelf break. Time series of volume transport across northern and southern boundaries were very similar and associated with variations in the alongshore wind stress and sea level, indicative of a geostrophic balance. Examination of the individual current meter records indicated these fluctuations were very barotropic even during deployment 2, which included the stratified summer season. Time series of the volume transport across the eastern boundary at the shelf break strongly mirrored the volume transport across the northern boundary minus that across the southern boundary, suggesting that the inferred eastern boundary transport was real and accommodated whatever the southern boundary could not. The turbulent salt flux across each boundary contributes very little to the net respective mass fluxes because the salt fluxes are almost governed by current velocity fields. The instantaneous and mean salt fluxes across each boundary were very well approximated by the instantaneous and mean volume transports across the boundary times the deployment average salinity across that boundary, respectively. The Ocean Margins Program (OMP) moored

  17. End-Pleistocene Soil Constituents from Selected Sites on the Mid-Atlantic Coastal Plain: First Results

    NASA Astrophysics Data System (ADS)

    Lecompte, M. A.; Rock, B. N.; Demitroff, M.; Reid, M.; Lucas, L.; Hughes, D.; Hayden, L. B.

    2008-12-01

    Stratigraphic analyses of soil samples taken from dated and undated sites located along the mid-Atlantic Coastal Plain have yielded evidence of increased contemporary biomass burning, compared to under and overlying strata. Host strata ages are known or projected to bracket the onset of the Younger Dryas cooling episode at 12.9 cal ka. This ongoing investigation includes samples from: 1) a late-Pleistocene aged periglacial feature located within the Pine Barrens of southern New Jersey; 2) an artifact dated stratum (~ 12.9 ka) in an embankment on the Chesapeake Bay in Maryland; and 3) an as yet undated (C14 test results pending) embankment of the Perquimans River in northeastern North Carolina projected to be age-appropriate. Sample analysis of scanning electron (SEM) micrographs from the Chesapeake Bay site revealed charred fragments of late-Wisconsinan Krummholz birch (Betula) and species of spruce (Picea) and fir (Abies), which are not extant on the modern-day, temperate Coastal Plain. In addition, organic faunal material is found in association with ancient charred boreal wood, including hollow hair and skin fragments that are as yet unidentified, perhaps from cold climate adapted animals as inferred from host sediment age. Charred wood fragments are found to be attracted to a neodymium magnet. Some aggregates of organic matter appear to contain magnetic spherule-like grains whose composition is awaiting geochemical analysis. Photomicrographs of all specimens and a stratigraphic breakdown in the relative amount of burned carbon associated with each site and strata will be presented, along with the results of various analyses that are currently underway.

  18. Novel Bacterial and Archaeal Lineages from an In Situ Growth Chamber Deployed at a Mid-Atlantic Ridge Hydrothermal Vent

    PubMed Central

    Reysenbach, Anna-Louise; Longnecker, Krista; Kirshtein, Julie

    2000-01-01

    The phylogenetic diversity was determined for a microbial community obtained from an in situ growth chamber placed on a deep-sea hydrothermal vent on the Mid-Atlantic Ridge (23°22′ N, 44°57′ W). The chamber was deployed for 5 days, and the temperature within the chamber gradually decreased from 70 to 20°C. Upon retrieval of the chamber, the DNA was extracted and the small-subunit rRNA genes (16S rDNA) were amplified by PCR using primers specific for the Archaea or Bacteria domain and cloned. Unique rDNA sequences were identified by restriction fragment length polymorphisms, and 38 different archaeal and bacterial phylotypes were identified from the 85 clones screened. The majority of the archaeal sequences were affiliated with the Thermococcales (71%) and Archaeoglobales (22%) orders. A sequence belonging to the Thermoplasmales confirms that thermoacidophiles may have escaped enrichment culturing attempts of deep-sea hydrothermal vent samples. Additional sequences that represented deeply rooted lineages in the low-temperature eurarchaeal (marine group II) and crenarchaeal clades were obtained. The majority of the bacterial sequences obtained were restricted to the Aquificales (18%), the ɛ subclass of the Proteobacteria (ɛ-Proteobacteria) (40%), and the genus Desulfurobacterium (25%). Most of the clones (28%) were confined to a monophyletic clade within the ɛ-Proteobacteria with no known close relatives. The prevalence of clones related to thermophilic microbes that use hydrogen as an electron donor and sulfur compounds (S0, SO4, thiosulfate) indicates the importance of hydrogen oxidation and sulfur metabolism at deep-sea hydrothermal vents. The presence of sequences that are related to sequences from hyperthermophiles, moderate thermophiles, and mesophiles suggests that the diversity obtained from this analysis may reflect the microbial succession that occurred in response to the shift in temperature and possible associated changes in the chemistry of the

  19. Geochemistry of vent fluid particles formed during initial hydrothermal fluid-seawater mixing along the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Klevenz, Verena; Bach, Wolfgang; Schmidt, Katja; Hentscher, Michael; Koschinsky, Andrea; Petersen, Sven

    2011-10-01

    We present geochemical data of black smoker particulates filtered from hydrothermal fluids with seawater-dilutions ranging from 0-99%. Results indicate the dominance of sulphide minerals (Fe, Cu, and Zn sulphides) in all samples taken at different hydrothermal sites on the Mid-Atlantic Ridge. Pronounced differences in the geochemistry of the particles between Logatchev I and 5°S hydrothermal fields could be attributed to differences in fluid chemistry. Lower metal/sulphur ratios (Me/H2S < 1) compared to Logatchev I result in a larger amount of particles precipitated per liter fluid and the occurrence of elemental sulphur at 5°S, while at Logatchev I Fe oxides occur in larger amounts. Systematic trends with dilution degree of the fluid include the precipitation of large amounts of Cu sulphides at a low dilution and a pronounced drop with increasing dilution. Moreover, Fe (sulphides or oxides) precipitation increases with dilution of the vent fluid by seawater. Geochemical reaction path modeling of hydrothermal fluid-seawater mixing and conductive cooling indicates that Cu sulphide formation at Logatchev I and 5°S mainly occurs at high temperatures and low dilution of the hydrothermal fluid by seawater. Iron precipitation is enhanced at higher fluid dilution, and the different amounts of minerals forming at 5°S and Logatchev I are thermodynamically controlled. Larger total amounts of minerals and larger amounts of sulphide precipitate during the mixing path when compared to the cooling path. Differences between model and field observations do occur and are attributable to closed system modeling, to kinetic influences and possibly to organic constituents of the hydrothermal fluids not accounted for by the model.

  20. Analysis of a PAH-degrading bacterial population in subsurface sediments on the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Shao, Zongze; Cui, Zhisong; Dong, Chunming; Lai, Qiliang; Chen, Liang

    2010-05-01

    Little is known about the types and concentrations of polycyclic aromatic hydrocarbons (PAHs) existing in the deep-sea subsurface environment, which is believed to be cold, oligothrophic and of high static pressure. PAHs in the upper layers of the water column are unavoidably subjected to degradation while they are deposited to the sea floor and become embedded in the deep-sea sediment. In this report, a high concentration of PAHs was discovered in the sediment 2.7 m beneath the bottom surface at a water depth of 3962 m on the Mid-Atlantic Ridge (MAR). The total concentration of PAHs was 445 ng (g dry wt sediment) -1. Among the seven detected PAHs, the concentrations of phenanthrene (222 ng g -1) and fluorene (79 ng g -1) were relatively high. In addition, PAH-degrading bacteria were found within the sediments. As in a previously detected site on the MAR, in the PAH-enriched region of this site, a bacterium of the genus Cycloclasticus was found to be the predominant isolate detected by PCR-DGGE analysis. In addition, bacteria of the Halomonas, Marinobacter, Alcanivorax, Thalassospira and Maricaulis genera, were also included in the PAH-degrading community. In summary, a high concentration of PAHs was detected in the subsurface of the deep-sea sediment, and once again, the Cycloclasticus bacterium was confirmed to be a ubiquitous marine PAH degrader even in the subsurface marine environment. Considering the abundance of PAHs therein, biodegradation is thus thought to be inactive, probably because of the low temperature, limited oxygen and/or limited nutrients.

  1. A study of job satisfaction of nursing and allied health graduates from a Mid-Atlantic university.

    PubMed

    Lyons, Kevin J; Lapin, Jennifer; Young, Barbara

    2003-01-01

    There have been numerous changes in the health care system, including cost-containment efforts, the increased growth of managed care, and shortages of many health professionals. It is important to assess the impact these changes are having on the quality of health care delivery and the way various health professionals view their jobs. To accomplish this assessment, a sample of experienced nursing and allied health professionals were asked to provide their assessment of positive and negative changes in the health system over a 5-year period. They also were asked to indicate their level of satisfaction with their profession, their current job, and various aspects of that job. A Health Care Environment Survey was mailed to six groups of graduates of a mid-Atlantic college of health professions. Three of the groups had been in practice for 5 years, and three of the groups had been in practice for 10 years. The survey asked respondents to assess the magnitude of certain changes in the health system over the previous 5 years and to provide an assessment of their satisfaction with their current job. A total of 1,610 surveys were mailed, and 787 were returned for a rate of 49%. Nursing and allied health professionals who responded to the survey reported that there have been many more negative than positive changes in the health care system, including less job security, efficiency, and time available to spend with individual patients and increases in workload, paperwork, and control of health care by insurance companies. Even with these negative changes, nurses and allied health professionals report a high level of satisfaction with their jobs. In investigating the aspects of their jobs that were most related to satisfaction, having a feeling of worthwhile accomplishment from their job, opportunities for personal and professional growth, recognition and satisfaction with their workload were found to be the best predictors of job satisfaction. PMID:12665288

  2. Comparing biosignatures from North Pond, Mid-Atlantic Ridge and the Louisville Seamount Chain, off New Zealand

    NASA Astrophysics Data System (ADS)

    Türke, Andreas; Ménez, Bénédicte; Bach, Wolfgang

    2016-04-01

    The subseafloor ocean represents Earth's largest aquifer and the flow of seawater fluxed through these flanks is > 1016 L/yr, rivaling the rate of river discharge into the oceans. When volcanic basalt glass is exposed to oxygen-rich seawater, rims of palagonite form at the expense of glass. Within subseafloor basalt glass, a range of putative microbial biosignatures have been interpreted as traces of life in these basaltic aquifers, and these have been studied as a potential analogue for early life on Earth or extraterrestrial habitats for several years. However, little is known about the relationship of the physical and chemical nature of the habitat and the prevalent types of biosignatures. We report and compare biosignatures from two distinctly different study sites that vary strongly. We analyzed rock samples microscopically for their putative textural biosignatures and their associated organic molecules via Fourier transform infrared spectrometry. The biosignatures found in basalts from the North Pond Region, at the western flank of the Mid-Atlantic Ridge 23°N, which is young well-oxygenated crust, are characterized by a small textural diversity. However, the organic molecules associated, show evidence for the occurrence of complex molecules like proteins. In contrast, the biosignatures from the Louisville Seamount Chain, which are much older (50 - 80 Ma), are more diverse in terms of textures, while the organic molecules are more degraded and suggest an Archaeal origin. We propose that microbial communities change significantly during crustal evolution and that microbes associated with older and severely altered crust may not be related to the textures commonly found within subseafloor basalt glass and often interpreted as trace fossils.

  3. Fish parasites in the bathyal zone: The halosaur Halosauropsis macrochir (Günther, 1878) from the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Klimpel, S.; Palm, H. W.; Busch, M. W.; Kellermanns, E.

    2008-01-01

    A total of 42 Halosauropsis macrochir from a single position on the Mid-Atlantic Ridge (MAR) were collected for studies on parasites and feeding ecology. A total of 9 different parasite species were found, with most of them belonging to the Digenea (4 species) and Nematoda (3). The host specific Degeneria halosauri, (Digenea) and Cystidicolidae indet. (Nematoda) were the predominant species, reaching a prevalence of 100.0% and 57.1% with intensities of infection of 1-12 and 1-10, respectively. Less host specific parasites such as Gonocerca phycidis (Digenea) and Tetraphyllidea indet. (Cestoda) occurred at low rates of infection. The parasite fauna of this bathyal fish can be described as predominantly adult and host specific, with larval and less host specific components. A total of 16 different food groups were identified, most of them of benthic origin or associated with the benthopelagial. The predominant prey organisms belonged to the Crustacea (e.g., Copepoda, Gammaridea, Amphipoda and Isopoda), which serve as main parasite vectors for H. macrochir. This deep-sea fish seems to follow a general pattern of fish parasites in the deep sea, with most isolated parasites belonging to the digeneans, nematodes and a cestode. The parasite composition is caused by the narrow depth range of the species and the restricted distribution of the fish family Halosauridae. The species richness was found to be lower than other demersal fish from the deep sea and shallow waters, however, higher than those from deep-sea fish living in the pelagial.

  4. Turbulence and finestructure in a deep ocean channel with sill overflow on the mid-Atlantic ridge

    NASA Astrophysics Data System (ADS)

    Tippenhauer, Sandra; Dengler, Marcus; Fischer, Tim; Kanzow, Torsten

    2015-05-01

    Diapycnal mixing in the deep ocean is known to be much stronger in the vicinity of rough topography of mid-ocean ridges than above abyssal plains. In this study a horizontally profiling microstructure probe attached to an autonomous underwater vehicle (AUV) is used to infer the spatial distribution of the dissipation rate of turbulent kinetic energy (ε) in the central valley of the Mid-Atlantic Ridge. To the authors' knowledge, this is the first successful realization of a horizontal, deep-ocean microstructure survey. More than 22 h of horizontal, near-bottom microstructure data from the Lucky Strike segment (37°N) are presented. The study focuses on a channel with unidirectional sill overflow. Density was found to decrease along the channel following the mean northward flow of 3 to 8 cm/s. The magnitude of the rate of turbulent kinetic energy dissipation was distributed asymmetrically relative to the position of the sill. Elevated dissipation rates were present in a segment 1-4 km downstream (north) of the sill with peak values of 1 ×10-7 W/kg. Large flow speeds and elevated density finestructure were observed within this segment. Lowered hydrographic measurements indicated unstable stratification in the same region. The data indicate that hydraulic control was established at least temporarily. Inside the channel at wavelengths between 1 m and 250 m the slopes of AUV-inferred horizontal temperature gradient spectra were found to be consistent with turbulence in the inertial-convective subrange. Integrated temperature gradient variance in this wavelength interval was consistent with an ε2/3 dependence. The results illustrate that deep-reaching AUVs are a useful tool to study deep ocean turbulence over complex terrain where free-falling and lowered turbulence measurements are inefficient and time-consuming.

  5. OBS records of Whale vocalizations from Lucky-strike segment of the Mid-Atlantic Ridge during 2007-2008

    NASA Astrophysics Data System (ADS)

    Chauhan, A.; Rai, A.; Singh, S. C.; Crawford, W. C.; Escartin, J.; Cannat, M.

    2009-12-01

    Passive seismic experiments to study seismicity require a long term deployment of ocean-bottom seismometers (OBSs). These instruments also record a large amount of non-seismogenic signals such as movement of large ships, air-gun shots, and marine mammal vocalizations. We report a bi-product of our passive seismic experiment (BBMOMAR) conducted around the Lucky-strike hydrothermal field of the slow-spreading mid-Atlantic ridge. Five multi-component ocean-bottom seismometers (recording two horizontal, one vertical and one pressure channel) were deployed during 2007-2008. During 13 months of deployment, abundant vocalizations of marine mammals have been recorded by all the five equipments. By analyzing the frequency content of data and their pattern of occurrence, we conclude that these low-frequency vocalizations (~20-40 Hz) typically corresponds to blue and fin-whales. These signals if not identified, could be mis-interpreted as underwater seismic/hydrothermal activity. Our data show an increase in the number of vocalizations recorded during the winter season relative to the summer. As part of the seismic monitoring of the Lucky-strike site, we anticipate to extend this study to the 2008-2009 and 2009-2010 periods, after the recovery and deployment of the array during the BATHYLUCK09 cruise. Long-term and continuous records of calls of marine mammals provide valuable information that could be used to identify the species, study their seasonal behaviour and their migration paths. Our study suggestes that passive experiments such as ocean-bottom seismometers deployed at key locations, could provide useful secondary infromation about oceanic species besides recording seismicity, which is otherwise not possible without harming or interfering with their activity.

  6. Characteristic length scales and time-averaged transport velocities of suspended sediment in the mid-Atlantic Region, USA

    USGS Publications Warehouse

    Pizzuto, James; Schenk, Edward R.; Hupp, Cliff R.; Gellis, Allen; Noe, Greg; Williamson, Elyse; Karwan, Diana L.; O'Neal, Michael; Marquard, Julia; Aalto, Rolf; Newbold, Denis

    2014-01-01

    Watershed Best Management Practices (BMPs) are often designed to reduce loading from particle-borne contaminants, but the temporal lag between BMP implementation and improvement in receiving water quality is difficult to assess because particles are only moved downstream episodically, resting for long periods in storage between transport events. A theory is developed that describes the downstream movement of suspended sediment particles accounting for the time particles spend in storage given sediment budget data (by grain size fraction) and information on particle transit times through storage reservoirs. The theory is used to define a suspended sediment transport length scale that describes how far particles are carried during transport events, and to estimate a downstream particle velocity that includes time spent in storage. At 5 upland watersheds of the mid-Atlantic region, transport length scales for silt-clay range from 4 to 60 km, while those for sand range from 0.4 to 113 km. Mean sediment velocities for silt-clay range from 0.0072 km/yr to 0.12 km/yr, while those for sand range from 0.0008 km/yr to 0.20 km/yr, 4–6 orders of magnitude slower than the velocity of water in the channel. These results suggest lag times of 100–1000 years between BMP implementation and effectiveness in receiving waters such as the Chesapeake Bay (where BMPs are located upstream of the characteristic transport length scale). Many particles likely travel much faster than these average values, so further research is needed to determine the complete distribution of suspended sediment velocities in real watersheds.

  7. Trawled megafaunal invertebrate assemblages from bathyal depth of the Mid-Atlantic Ridge (48°-54°N)

    NASA Astrophysics Data System (ADS)

    Alt, Claudia H. S.; Rogacheva, Antonina; Boorman, Benjamin; Alan Hughes, J.; Billett, David S. M.; Gooday, Andrew J.; Jones, Daniel O. B.

    2013-12-01

    We investigated the effects of contrasting surface primary production on the benthic invertebrate megafauna at four sites on the Mid-Atlantic Ridge. The sites, designated NW, NE, SW and SE, were located to the west and east of the Ridge axis and to the north and south of the Charlie-Gibbs Fracture Zone. Benthic megafauna were sampled in 2007 and 2009 with a semi-balloon otter trawl, at a target depth of 2,500 m. The total biomass and density of major taxonomic groups did not differ significantly between sites, despite those to the north being characterised by greater surface productivity than those to the south. However, the density and biomass of individual taxonomic groups, as well as diversity and body size, all showed significant differences between sites. Diversity was highest at the SE, and lowest at the NE site. Most species were larger to the north. Community composition was significantly different between all sites, with the greatest number of unique species found at the SE, and noticeably fewer unique species at the northern sites. There was no clear correlation between the surface productivity and community structure, suggesting complex ecological controls on the communities. It is speculated that, in addition to the energy supply, drivers such as strong currents and sediment characteristics, play an important role in shaping the communities at the different sites. To what extent the ridge acts as a dispersal barrier for benthic invertebrate fauna remains unclear. However, high numbers of species unique to the southern site suggest a limited dispersal between the northern and southern areas.

  8. Active and relict sea-floor hydrothermal mineralization at the TAG hydrothermal field, Mid-Atlantic Ridge

    SciTech Connect

    Rona, P.A. . Atlantic Oceanographic and Meteorological Labs.); Hannington, M.D. ); Raman, C.V. ); Thompson, G.; Tivey, M.K.; Humphris, S.E. ); Lalou, C. . Lab. CNRS-CEA); Petersen, S. Aachen Univ. of Technology )

    1993-12-01

    The TAG hydrothermal field is a site of major active and inactive volcanic-hosted hydrothermal mineralization in the rift valley of the slow-spreading Mid-Atlantic Ridge at 26[degree]N. The axial high is the principal locus of present magmatic intrusions. The TAG field contains three main areas of present and past hydrothermal activity: (1) an actively venting high-temperature sulfide mound; (2) two former high-temperature vent areas; (3) a zone of low-temperature venting and precipitation of Fe and Mn oxide deposits. The volcanic centers occur at the intersections between ridge axis-parallel normal faults and projected axis-transverse transfer faults. The intersections of these active fault systems may act as conduits both for magmatic intrusions from sources beneath the axial high that build the volcanic centers and for hydrothermal upwelling that taps the heat sources. Radiometric dating of sulfide samples and manganese crusts in the hydrothermal zones and dating of sediments intercalated with pillow lava flows in the volcanic center adjacent to the active sulfide mound indicate multiple episodes of hydrothermal activity throughout the field driven by heat supplied by episodic intrusions over a period of at least 140 [times] 10[sup 3] yr. The sulfide deposits are built by juxtaposition and superposition during relatively long residence times near episodic axial heat sources counterbalanced by mass wasting in the tectonically active rift valley of the slow-spreading oceanic ridge. Hydrothermal reworking of a relict hydrothermal zone by high-temperature hydrothermal episodes has recrystallized sulfides and concentrated the first visible primary gold reported in a deposit at an oceanic ridge.

  9. Comparing strengths of geographic and nongeographic classifications of stream benthic macroinvertebrates in the Mid-Atlantic Highlands, USA

    USGS Publications Warehouse

    Waite, I.R.; Herlihy, A.T.; Larsen, D.P.; Klemm, D.J.

    2000-01-01

    The US Environmental Protection Agency's (USEPA) Environmental Monitoring and Assessment Program (EMAP) sampled ~500 wadeable streams in the Mid-Atlantic Highlands region of the US during the late spring of 1993 to 1995 for a variety of physical, chemical, and biological indicators of environmental condition. Eighty-eight sites that were minimally affected by human activities were chosen to determine the extent to which geographic and stream-based classifications accounted for variation in the composition of riffle macroinvertebrate assemblages. Bray-Curtis similarities among sites were calculated from the relative abundance of macroinvertebrates to assess the strength of classifications based on geography (ecoregions and catchments), habitat (slope and stream order), and water chemistry (conductivity). For comparison, a taxonomic classification (two-way indicator species analysis, TWINSPAN) and a gradient analysis (correspondence analysis, CA) were performed on the macroinvertebrate data. To assess the effect of taxonomic resolution, all analyses were completed at the family level and to lowest practical taxon. The large overall variation within and among ecoregions resulted in a low average classification strength (CS) of ecoregions, although some ecoregions had high CS. Stream order had the highest CS of the habitat and water chemistry classifications. Ecoregion CS increased, however, when stream sites were 1(st) stratified by stream order (ecoregions nested within stream order). Nested ecoregion CS did not increase within 1(st)-order streams, yet increased within 2(nd)- and 3(rd)-order streams. CA ordinations and TWINSPAN classification showed a clear gradient of streams along stream size (order), with a clear separation of 1(st)- and 3(rd)-order streams based on macroinvertebrate composition. The ordinations did not, however, show a distinct clustering of sites on the basis of ecoregions. Overall, the lowest practical taxon level of identification resulted in

  10. Distribution of the biomass-dominant pelagic fish, Bathylagus euryops (Argentiniformes: Microstomatidae), along the northern Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Sweetman, C. J.; Sutton, T. T.; Vecchione, M.; Latour, R. J.

    2013-08-01

    The northern Mid-Atlantic Ridge (MAR), from Iceland to the Azores, ranges in depth from 800-4500 m and extends over an area of 3.7 million km2. Despite its size, few studies have described the distribution of pelagic fishes along the MAR. Recent evidence from MAR-ECO, a Census of Marine Life field project, reported increased abundance and biomass of deep-pelagic fishes below 1000 m on the ridge, which stands in stark contrast to the traditional view that abundance and biomass decline exponentially with increasing depth in ‘typical’ open ocean ecosystems. Among the midwater fishes sampled during the MAR-ECO campaign, Bathylagus euryops (Argentiniformes: Microstomatidae) was the biomass-dominant pelagic species and ranked third in total abundance. In this paper, we characterize the distribution of B. euryops in relation to physical and biological variables along the MAR. Average catch of B. euryops over the MAR varied between 0.68 individuals/100,000 m3±0.70 individuals at the Azorean Zone and 5.82 individuals/100,000 m3±2.08 individuals at the Reykjanes Ridge. Generalized linear models applied to B. euryops catch data indicated that ridge section, depth zone, and prey abundance were important explanatory variables in structuring the distribution along the MAR. Analyses of vertical distribution patterns, relative to time of day and fish size, showed that larger fish were found deeper in the water column, likely due to an ontogenetic migration to depth. Mean fish size increased from 58.9 mm standard length in the epipelagic zone and continually increased to 155.7 mm standard length between 2300-3000 m. Due to the high abundance and biomass observed along the MAR, B. euryops appears to be an important species in the oceanic food web of the North Atlantic Ocean.

  11. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (Mid-Atlantic). Striped Bass

    SciTech Connect

    Fay, C.W.; Neves, R.J.; Pardue, G.B.

    1983-10-01

    Species profiles are literature summaries on the taxonomy, morphology, range, life history, and environmental requirements of coastal aquatic species. The striped bass (Morone saxatilis) is a highly valued recreational and commercial fish species and is surpassed in total recreational catch (weight) only by bluefish and Atlantic mackerel on the Atlantic coast. Males mature at age 2 or 3, and females at age 4 or 5. Striped bass are anadromous, spawning in fresh or nearly fresh water, from April through June in the Mid-Atlantic region. Upper Chesapeake Bay, its major tributaries, and the Chesapeake-Delaware Canal are the most important spawning grounds on the Atlantic coast. Eggs are semibuoyant, and require a minimum current velocity of 30.5 cm/s during development to keep them from settling and smothering on the bottom. Environmental conditions during the larval stage are considered most crucial in terms of future year class strength. Juveniles remain in or near areas of origin for 2 or 3 years, at which time a portion of the juveniles may join coastal migratory stocks, moving north in spring and summer and south in fall and winter. Temperature, salinity, current velocity, and turbidity are important environmental factors for striped bass. Eggs require water temperatures between 14/sup 0/C and 23/sup 0/C, salinities between 0 and 10 ppt, water currents of at least 30.5 cm/s, and turbidities less than 1000 mg/l for successful development and hatching. Larvae require temperatures between 10/sup 0/C and 25/sup 0/C, salinities between 0 and 15 ppt, and turbidities less than 500 mg/1 for survival. Juvenile and adult tolerances are generally wider. 171 references, 4 figures, 9 tables.

  12. Serpentinization of abyssal peridotites from the MARK area, Mid-Atlantic Ridge: Sulfur geochemistry and reaction modeling

    USGS Publications Warehouse

    Alt, J.C.; Shanks, Wayne C., III

    2003-01-01

    The opaque mineralogy and the contents and isotope compositions of sulfur in serpentinized peridotites from the MARK (Mid-Atlantic Ridge, Kane Fracture Zone) area were examined to understand the conditions of serpentinization and evaluate this process as a sink for seawater sulfur. The serpentinites contain a sulfur-rich secondary mineral assemblage and have high sulfur contents (up to 1 wt.%) and elevated ??34Ssulfide (3.7 to 12.7???). Geochemical reaction modeling indicates that seawater-peridotite interaction at 300 to 400??C alone cannot account for both the high sulfur contents and high ??34Ssulfide. These require a multistage reaction with leaching of sulfide from subjacent gabbro during higher temperature (???400??C) reactions with seawater and subsequent deposition of sulfide during serpentinization of peridotite at ???300??C. Serpentinization produces highly reducing conditions and significant amounts of H2 and results in the partial reduction of seawater carbonate to methane. The latter is documented by formation of carbonate veins enriched in 13C (up to 4.5???) at temperatures above 250??C. Although different processes produce variable sulfur isotope effects in other oceanic serpentinites, sulfur is consistently added to abyssal peridotites during serpentinization. Data for serpentinites drilled and dredged from oceanic crust and from ophiolites indicate that oceanic peridotites are a sink for up to 0.4 to 6.0 ?? 1012 g seawater S yr-1. This is comparable to sulfur exchange that occurs in hydrothermal systems in mafic oceanic crust at midocean ridges and on ridge flanks and amounts to 2 to 30% of the riverine sulfate source and sedimentary sulfide sink in the oceans. The high concentrations and modified isotope compositions of sulfur in serpentinites could be important for mantle metasomatism during subduction of crust generated at slow spreading rates. ?? 2003 Elsevier Science Ltd.

  13. Characteristic length scales and time-averaged transport velocities of suspended sediment in the mid-Atlantic Region, USA

    NASA Astrophysics Data System (ADS)

    Pizzuto, James; Schenk, Edward R.; Hupp, Cliff R.; Gellis, Allen; Noe, Greg; Williamson, Elyse; Karwan, Diana L.; O'Neal, Michael; Marquard, Julia; Aalto, Rolf; Newbold, Denis

    2014-02-01

    Watershed Best Management Practices (BMPs) are often designed to reduce loading from particle-borne contaminants, but the temporal lag between BMP implementation and improvement in receiving water quality is difficult to assess because particles are only moved downstream episodically, resting for long periods in storage between transport events. A theory is developed that describes the downstream movement of suspended sediment particles accounting for the time particles spend in storage given sediment budget data (by grain size fraction) and information on particle transit times through storage reservoirs. The theory is used to define a suspended sediment transport length scale that describes how far particles are carried during transport events, and to estimate a downstream particle velocity that includes time spent in storage. At 5 upland watersheds of the mid-Atlantic region, transport length scales for silt-clay range from 4 to 60 km, while those for sand range from 0.4 to 113 km. Mean sediment velocities for silt-clay range from 0.0072 km/yr to 0.12 km/yr, while those for sand range from 0.0008 km/yr to 0.20 km/yr, 4-6 orders of magnitude slower than the velocity of water in the channel. These results suggest lag times of 100-1000 years between BMP implementation and effectiveness in receiving waters such as the Chesapeake Bay (where BMPs are located upstream of the characteristic transport length scale). Many particles likely travel much faster than these average values, so further research is needed to determine the complete distribution of suspended sediment velocities in real watersheds.

  14. Estimating population abundance and mapping distribution of wintering sea ducks in coastal waters of the mid-Atlantic

    USGS Publications Warehouse

    Koneff, M.D.; Royle, J. Andrew; Forsell, D.J.; Wortham, J.S.; Boomer, G.S.; Perry, M.C.

    2005-01-01

    Survey design for wintering scoters (Melanitta sp.) and other sea ducks that occur in offshore waters is challenging because these species have large ranges, are subject to distributional shifts among years and within a season, and can occur in aggregations. Interest in winter sea duck population abundance surveys has grown in recent years. This interest stems from concern over the population status of some sea ducks, limitations of extant breeding waterfowl survey programs in North America and logistical challenges and costs of conducting surveys in northern breeding regions, high winter area philopatry in some species and potential conservation implications, and increasing concern over offshore development and other threats to sea duck wintering habitats. The efficiency and practicality of statistically-rigorous monitoring strategies for mobile, aggregated wintering sea duck populations have not been sufficiently investigated. This study evaluated a 2-phase adaptive stratified strip transect sampling plan to estimate wintering population size of scoters, long-tailed ducks (Clangua hyemalis), and other sea ducks and provide information on distribution. The sampling plan results in an optimal allocation of a fixed sampling effort among offshore strata in the U.S. mid-Atlantic coast region. Phase I transect selection probabilities were based on historic distribution and abundance data, while Phase 2 selection probabilities were based on observations made during Phase 1 flights. Distance sampling methods were used to estimate detection rates. Environmental variables thought to affect detection rates were recorded during the survey and post-stratification and covariate modeling were investigated to reduce the effect of heterogeneity on detection estimation. We assessed cost-precision tradeoffs under a number of fixed-cost sampling scenarios using Monte Carlo simulation. We discuss advantages and limitations of this sampling design for estimating wintering sea duck

  15. Mid-Atlantic

    Atmospheric Science Data Center

    2014-05-15

    ... as a function of view angle are visible over both land and water. Scientists are using MISR data to monitor changes in clouds, Earth's surface, and pollution particles in the air, and to assess their impact on climate. MISR ...

  16. Modes of deformation in ultramafic rocks exhumed in the footwall of detachment faults at the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Picazo, S. M.; Cannat, M.; Delacour, A.; Silantiev, S.; Fouquet, Y.

    2010-12-01

    Mantle exhumation by detachment faulting is common at slow spreading mid-ocean ridges. We present deformation structures related to exhumation in ultramafic and associated mafic rocks which were dredged and sampled by ROV during the SERPENTINE cruise (2007) in the footwall of detachments along the Mid-Atlantic Ridge: next to the Ashadze vent field at 13°N, and to the Logatchev vent field at 14°45'N. At these two locations, the main fault zones have been eroded by rockslides. However, we infer that our samples come from < 200m of these main faults. The exhumed rocks belong to 4 lithological types in varying proportions: metabasalts and metadolerites (0,5 to 54%), metagabbros (0,1 to 18%), and serpentinized peridotites with (25 to 49%) and without (2 to 74%) gabbroic injections. We focused our study on these last two types and identified 4 types of deformation. For each type of deformation, we use the weight % of affected samples as an indicator of the distributed character of this deformation in the detachment footwall. Only 0,2% of the ultramafic rocks is affected to some degree by lithospheric ductile deformation with recrystallization of primary minerals (olivine, pyroxenes). 17% presents brittle-ductile shear zones. Most of these shear zones contains mineral assemblages typical of greenschist facies hydrous alteration of gabbroic material (tremolite after hornblende, chlorite after plagioclase, and occasional zircon). These minerals, with serpentine and less common talc are recrystallized, or kinked and fractured. A small number of shear zones are comprised of strongly oriented tremolite fibbers with post-kinematic replacement by talc and carbonates. These are interpreted as sheared hydrothermal veins. Matrix-supported cataclasites are observed in samples collected near the Logatchev vent field, where they represent 13% of the ultramafics. These cataclasites contain serpentinized and gabbroic clasts in a matrix of sheared and/or fractured chlorite, serpentine

  17. Legacy effects of colonial millponds on floodplain sedimentation, bank erosion, and channel morphology, MID-Atlantic, USA

    USGS Publications Warehouse

    Schenk, E.R.; Hupp, C.R.

    2009-01-01

    Many rivers and streams of the Mid-Atlantic Region, United States (U.S.) have been altered by postcolonial floodplain sedimentation (legacy sediment) associated with numerous milldams. Little Conestoga Creek, Pennsylvania, a tributary to the Susquehanna River and the Chesapeake Bay, is one of these streams. Floodplain sedimentation rates, bank erosion rates, and channel morphology were measured annually during 2004-2007 at five sites along a 28-km length of Little Conestoga Creek with nine colonial era milldams (one dam was still in place in 2007). This study was part of a larger cooperative effort to quantify floodplain sedimentation, bank erosion, and channel morphology in a high sediment yielding region of the Chesapeake Bay watershed. Data from the five sites were used to estimate the annual volume and mass of sediment stored on the floodplain and eroded from the banks for 14 segments along the 28-km length of creek. A bank and floodplain reach based sediment budget (sediment budget) was constructed for the 28 km by summing the net volume of sediment deposited and eroded from each segment. Mean floodplain sedimentation rates for Little Conestoga Creek were variable, with erosion at one upstream site (-5 mm/year) to deposition at the other four sites (highest = 11 mm/year) despite over a meter of floodplain aggradation from postcolonial sedimentation. Mean bank erosion rates range between 29 and 163 mm/year among the five sites. Bank height increased 1 m for every 10.6 m of channel width, from upstream to downstream (R2 = 0.79, p < 0.0001) resulting in progressively lowered hydraulic connectivity between the channel and the floodplain. Floodplain sedimentation and bank erosion rates also appear to be affected by the proximity of the segments to one existing milldam, which promotes deposition upstream and scouring downstream. The floodplain and bank along the 28-km reach produced a net mean sediment loss of 5,634 Mg/year for 2004-2007, indicating that bank

  18. Observations of oceanic crust and mantle structures at a deep ocean seismic array in the Eastern Mid Atlantic

    NASA Astrophysics Data System (ADS)

    Hannemann, Katrin; Krüger, Frank; Dahm, Torsten

    2016-04-01

    In 2011, twelve ocean bottom stations (OBS) were installed approximately 100 km North of the Gloria Fault during the DOCTAR project (Deep OCean Test ARray). This fault marks the plate boundary between the Eurasian and African plate in the North Eastern Mid Atlantic. The experiment took place in water depth of 4-6 km, 800 km West of the Portuguese coast. The stations were equipped with broad band seismometers which recorded for ten months. We employ P and S receiver functions (RF) to have a closer look at the structure of crust and mantle. The ocean is a quite noisy environment, therefore the number of usable events is low (around 20) compared to RF studies on land. We use several quality criteria (e.g. signal to noise ratio, relative spike position) to select proper processing parameters for the calculation of the RF and carefully reviewed all later on used RF. Despite the low number of events, the usage of an array of OBS with an aperture of 75 km allows us to investigate deeper discontinuities (e.g. in 410 and 660 km depth) compared to single station approaches which are usually employed for OBS. Furthermore, we increase the number of usable events by applying array methods. We use move out corrected and stacked RF to have a closer look at the mantle transition zone, and estimate average depth values for the Moho, the lithosphere asthenosphere boundary (LAB) and the base of the asthenosphere. The Moho lies at depth of 7 km, the LAB at approximately 50 km and the asthenosphere has an approximated thickness of 110 km. We observe a slight increase in the time difference of the mantle discontinuity conversion times compared to PREM. RF give just information regarding the impedance contrast at a discontinuity instead of velocities. We additionally use P wave polarization of teleseismic events to estimate absolute S velocities beneath the single stations. All in all, we use the information gained by the RF analysis, and the analysis of the P wave polarization to

  19. A geological perspective on sea-level rise and its impacts along the U.S. mid-Atlantic coast

    NASA Astrophysics Data System (ADS)

    Miller, Kenneth G.; Kopp, Robert E.; Horton, Benjamin P.; Browning, James V.; Kemp, Andrew C.

    2013-12-01

    We evaluate paleo-, historical, and future sea-level rise along the U.S. mid-Atlantic coast. The rate of relative sea-level rise in New Jersey decreased from 3.5 ± 1.0 mm/yr at 7.5-6.5 ka, to 2.2 ± 0.8 mm/yr at 5.5-4.5 ka to a minimum of 0.9 ± 0.4 mm/yr at 3.3-2.3 ka. Relative sea level rose at a rate of 1.6 ± 0.1 mm/yr from 2.2 to 1.2 ka (750 Common Era [CE]) and 1.4 ± 0.1 mm/yr from 800 to 1800 CE. Geological and tide-gauge data show that sea-level rise was more rapid throughout the region since the Industrial Revolution (19th century = 2.7 ± 0.4 mm/yr; 20th century = 3.8 ± 0.2 mm/yr). There is a 95% probability that the 20th century rate of sea-level rise was faster than it was in any century in the last 4.3 kyr. These records reflect global rise (˜1.7 ± 0.2 mm/yr since 1880 CE) and subsidence from glacio-isostatic adjustment (˜1.3 ± 0.4 mm/yr) at bedrock locations (e.g., New York City). At coastal plain locations, the rate of rise is 0.3-1.3 mm/yr higher due to groundwater withdrawal and compaction. We construct 21st century relative sea-level rise scenarios including global, regional, and local processes. We project a 22 cm rise at bedrock locations by 2030 (central scenario; low- and high-end scenarios range of 16-38 cm), 40 cm by 2050 (range 28-65 cm), and 96 cm by 2100 (range 66-168 cm), with coastal plain locations having higher rises (3, 5-6, and 10-12 cm higher, respectively). By 2050 CE in the central scenario, a storm with a 10 year recurrence interval will exceed all historic storms at Atlantic City.

  20. Lipid Biomarkers and Carbon Isotopic Composition from Authigenic Carbonates and Seep Sediments from the US Mid-Atlantic Margin

    NASA Astrophysics Data System (ADS)

    Campbell, P.; Prouty, N.; Demopoulos, A. W.; Roark, B.; Coykendall, K.

    2015-12-01

    Anaerobic oxidation of methane (AOM), mediated by Archaea and sulfate-reducing bacteria, is common in continental margin sediment and can result in authigenic carbonate precipitation. A lipid biomarker study was undertaken in Mid-Atlantic submarine canyons, focusing specifically on Baltimore and Norfolk canyons, to determine biomarker variability of carbonate rock and the associated sediment in cold seep communities dominated by chemosynthetic mussels, Bathymodiolus childressi. Preliminary 16S metagenomic results confirm the presence of free-living sulfur-reducing bacteria and methantrophic endosymbiotic bacteria in the mussels. Depleted d13C values in both the mussel tissue (-63 ‰) and authigenic carbonates (-48 ‰) support methanotrophy as the dominant nutritional pathway and AOM as the main driver of carbonate precipitation. In addition, paired 14C and 230Th dates are highly discordant, reflecting dilution of the 14C pool with fossil hydrocarbon derived carbon. Seep and canyon sediment, as well as authigenic carbonates, were collected and analyzed for a suite of biomarkers, including sterols, alcohols, alkanes and fatty acids, as well as δ13C values of select biomarkers, to elucidate pathways of organic matter cycling. A comparison of terrestrial biomarker signatures (e.g., n-alkane carbon preference index and C23 / (C23 + C29) values, HMW n-alkanes and C29 sterols) suggests that terrestrial inputs dominate the submarine canyon surface sediment, whereas seep sediment is predominantly marine autochthonous (i.e., cholesterol and 5α-cholestanol). Lipid biomarker profiles (e.g., n-alkanes in the C15 to C33 range) from authigenic carbonates mirror those found in the seep sediment, suggesting that the organisms mediating carbonate precipitation on the seafloor are characteristic of the assemblages present in the sediment at these sites. With widespread methane leakage recently discovered along the Atlantic Margin, the presence of AOM-mediated carbonate

  1. In Search for Diffuse Hydrothermal Venting at North Pond, Western Flank of the Mid-Atlantic-Ridge

    NASA Astrophysics Data System (ADS)

    Villinger, H. W.; Becker, K.; Hulme, S.; Kaul, N. E.; Müller, P.; Wheat, C. G.

    2015-12-01

    We present results from temperature measurements made with a ROV temperature lance in sediments deposited on the slopes of abyssal hills and small basins surrounding North Pond. North Pond is a ~8x15 km large sediment basin located on ~7 Ma year old crust west of the Mid-Atlantic Ridge at 23°N. Data were collected with the ROV Jason II during cruise MSM37 on the German RV Maria S. Merian in April 2014. The temperature lance consists of a 60 cm long stainless steel tube (o.d. 12 mm) housing 8 thermistors with a spacing of 80 mm, resulting in an active length of 56 cm. Data are logged with an 8-channel data logger (XR-420-T8, RBR, Ottawa) and transmitted online to the control van of the ROV. Data reduction and temperature gradient calculation is done according to the HFRED algorithm (Villinger & Davis, 1987). 90 sites in total were visited, 88 gave good data for temperature gradient calculation. Calculated gradients are usually of good to very good quality. The gradients vary between less than 20 to more than 1000 mK/m reflecting the very heterogeneous distribution of geothermal heat flow. The expected conductive lithospheric heat flow for North Pond is ~190 mW/m2 (geothermal gradient of ~190 mK/m with a thermal conductivity of 1 W/Km). The highest temperature gradients are measured in places where temperature ~50 cm below the sediment-water boundary exceeds bottom water temperature by ~0.5 K . These high temperature gradients may reflect local hydrothermal circulation within the pillow lavas, however no focused discharge was detected. The analysis of temperature measurements made with the ROV-mounted CTD shows clearly detectable bottom water temperature anomalies. We infer that they are either caused by hydrothermal discharge through the thin sediment cover or through unsedimented pillow basalts nearby. Hydrothermal circulation in a North-Pond-like environment appears to be diffuse in nature, hence very difficult if not impossible to detect and to quantify.

  2. Seismic airgun sounds recorded on moored hydrophones near the Mid-Atlantic Ridge and East Pacific Rise

    NASA Astrophysics Data System (ADS)

    Mellinger, D. K.; Nieukirk, S. L.; Dziak, R. P.; Haxel, J. H.; Fox, C. G.

    2003-12-01

    Sounds of seismic airguns were detected in two years of data collected from large, remote areas near the Mid-Atlantic Ridge (MAR) and the East Pacific Rise (EPR). From February 1999-February 2001, six autonomous hydrophones were moored near the MAR between 15-35 N and 33-50 W, and six more were moored in the EPR between 8 N - 8 S and 95-110 W. Continuous acoustic data recovered from both arrays were examined for sounds associated with seismic airgun activity. This was done using an automatic detection algorithm designed to identify repetitive sounds in the 20-60 Hz band. Airgun impulses occurred every 10-20 s and were recorded frequently on all hydrophones. In the Atlantic, airgun activity peaked in the summer months, and airgun impulses were detected in nearly 100% of the hours examined; Pacific seasonal trends were less obvious. Because of the high source level of the airgun signals, it was possible to estimate the locations of ships conducting seismic surveys despite their great distance, often over 3,000 km from our array. In the Atlantic, we located seismic vessels, presumably commercial, working off the coast of Nova Scotia during summer, and off western Africa and northeast Brazil in spring, summer,and fall. During summer 1999, research airguns were recorded on the MAR near 26 N 50 W. In the eastern tropical Pacific, the predominant source of airgun sounds was seismic vessels in the nearshore waters of southern Ecuador and northern Peru. All of the areas in which intense airgun activity was detected include important habitat for marine mammals; one area included habitat of the critically endangered northern right whale. Sounds from airguns appear to be a major contributor to the sound field in the Atlantic and parts of the Pacific Ocean, and may be of concern given the recent interest in ocean noise and its effects on marine mammals. Acoustic pressure levels of earthquakes are also investigated, and received levels in some common marine mammal habitats are

  3. Geological Constraints on Ocean-Floor Detachment Faulting (Mid-Atlantic Ridge, Fifteen-Twenty Fracture Zone)

    NASA Astrophysics Data System (ADS)

    MacLeod, C. J.; Escartin, J.

    2001-12-01

    During RRS James Clark Ross cruise JR63 we made a detailed geological investigation of a number of corrugated massifs adjoining the Mid-Atlantic Ridge axis north of the Fifteen-Twenty fracture zone. This area is known to be one at which magma supply is low and where peridotite exposures are widespread in the axial valley. Spreading parallel striations are evident on our swath bathymetry, TOBI sidescan sonar images and seabed photographs over an area of some 300 sq. km. Wavelengths of the corrugations range from km down to mm in scale. We sampled the striated surfaces using the BRIDGE wireline rock drill, an electrically powered rotary coring device that can take azimuthally orientated metre-length cores from hard-rock seafloor. Core was retrieved at 65 sites out of 73 attempted at water depths of up to 4520m and on slopes of up to 44 degrees. Dredging (29 sites) was also carried out in order to sample the steeper flanks of the corrugated massifs. Drill cores commonly contain highly deformed schistose serpentinite with sub-horizontal fabrics. This is the first direct evidence that the corrugated surfaces indeed represent low angle detachment-type fault planes, and shows that they are lubricated by serpentinite. A cupola of gabbro underlies the shallowest of the corrugated massifs. It is more than 100 sq. km in area and has very irregular form. At its sides it intrudes undeformed serpentinised mantle peridotite, and its upper surface passes into a very extensive swarm of chilled dolerite dykes, locally sheeted, that intrude the deformed serpentinite. Deformation and magmatism were clearly synchronous: some dykes cut deformed serpentinite; others are deformed and incorporated into a sheared serpentinite mélange. Many dolerites and gabbros are cataclastically deformed and contain greenschist facies alteration assemblages. No evidence for high-temperature ductile deformation is observed. These relationships place important constraints on the geometry and deformation

  4. Predicting the timing of cherry blossoms in Washington, DC and Mid-Atlantic States in response to climate change.

    PubMed

    Chung, Uran; Mack, Liz; Yun, Jin I; Kim, Soo-Hyung

    2011-01-01

    Cherry blossoms, an icon of spring, are celebrated in many cultures of the temperate region. For its sensitivity to winter and early spring temperatures, the timing of cherry blossoms is an ideal indicator of the impacts of climate change on tree phenology. Here, we applied a process-based phenology model for temperate deciduous trees to predict peak bloom dates (PBD) of flowering cherry trees (Prunus×yedoensis 'Yoshino' and Prunus serrulata 'Kwanzan') in the Tidal Basin, Washington, DC and the surrounding Mid-Atlantic States in response to climate change. We parameterized the model with observed PBD data from 1991 to 2010. The calibrated model was tested against independent datasets of the past PBD data from 1951 to 1970 in the Tidal Basin and more recent PBD data from other locations (e.g., Seattle, WA). The model performance against these independent data was satisfactory (Yoshino: r(2) = 0.57, RMSE = 6.6 days, bias = 0.9 days and Kwanzan: r(2) = 0.76, RMSE = 5.5 days, bias = -2.0 days). We then applied the model to forecast future PBD for the region using downscaled climate projections based on IPCC's A1B and A2 emissions scenarios. Our results indicate that PBD at the Tidal Basin are likely to be accelerated by an average of five days by 2050 s and 10 days by 2080 s for these cultivars under a mid-range (A1B) emissions scenario projected by ECHAM5 general circulation model. The acceleration is likely to be much greater (13 days for 2050 s and 29 days for 2080s) under a higher (A2) emissions scenario projected by CGCM2 general circulation model. Our results demonstrate the potential impacts of climate change on the timing of cherry blossoms and illustrate the utility of a simple process-based phenology model for developing adaptation strategies to climate change in horticulture, conservation planning, restoration and other related disciplines. PMID:22087317

  5. New Pressure Results from the Expedition 336 CORKs at North Pond, Western Flank of the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Becker, K.; Villinger, H. W.; Davis, E. E.

    2014-12-01

    We report results from a nearly two-year record of pressure data from three CORK hydrogeological observatories in the ~8x15 km "North Pond" sedimented basin in ~7 Ma crust west of the mid-Atlantic Ridge at 23°N. The new data were recovered during operations with the ROV Jason from the German R/V Maria S. Merian in April of 2014. Two of the CORKs (in Holes U1382A and U1383C) had been installed during IODP Expedition 336 in fall of 2011, with an initial installment of 6-7 months data recovered in spring 2012, also by Jason from R/V Merian. The third hole, U1383B, was instrumented during the 2012 cruise with a "CORK-Lite" deployed by the ROV. All three installations monitor formation pressures in basement beneath the sediment pond. The new data confirm results of the first half-year of data, which suggested a slight formation overpressure (~10 kPa) relative to hydrostatic in the two full CORK installations. This was somewhat surprising given (a) the long history of downhole flow in DSDP Hole 395A that also penetrated basement beneath the sediment pond, and (b) prior observations at more thickly-sedimented eastern Pacific ridge flanks of formation underpressures in sites drilled into basement lows. The new results show a small phase lag and attenuation of formation tidal signals relative to seafloor tides that is the same in all three holes, which confirms that the CORKs are properly sealed at the seafloor. The phase lag and attenuation are also the same among three separate basement intervals in Hole U1383C, which suggests either that the entire drilled section is hydrogeologically well connected or that downhole packers between the intervals do not seal completely. We explore potential models to explain the slight observed overpressures. One possibility is that the geometry of the isolated sediment pond results in higher formation temperatures and less dense formation fluids immediately below the relatively impermeable sediment pond, such that surrounding cooler

  6. Effects of non-native earthworms on on below- and aboveground processes in the Mid-Atlantic region

    NASA Astrophysics Data System (ADS)

    Szlavecz, K. A.; McCormick, M. K.; Xia, L.; Pitz, S.; O'Neill, J.; Bernard, M.; Chang, C.; Whigham, D. F.

    2011-12-01

    Many biotic and abiotic disturbances have shaped the structure of the deciduous forests in the Mid-Atlantic region. One major anthropogenic factor is land use history. Agricultural practices in the past undoubtedly facilitated non-native earthworm colonization and establishment. Today most secondary forests are dominated by European lumbricid earthworms, although native species also occur in some habitats. To investigate how earthworm community composition and abundance affect belowground processes and tree seedling growth we set up a field manipulation experiment at the Smithsonian Environmental Research Center in Edgewater, MD. A total of 66 experimental plots were set up in successional (70 yrs) and mature (150 yrs) Tulip-poplar-Oak associations. We manipulated earthworm abundance and leaf litter input, and planted seedlings of Tulip poplar, Red maple, Red oak, and American beech. The experiment lasted for two years during which we regularly monitored density, biomass and species composition of earthworm assemblages and measured soil respiration. Soil moisture, temperature and air temperature were also continuously monitored using a wireless sensor network. At harvest, soil bulk density, pH, N pools, C:N ratio, potential N-mineralization rates, and enzyme activity were determined. We used quantitative PCR to assess the community composition of soil fungi. We also determined the extent of mycorrhizal colonization and biomass of roots, shoots and leaves. We conducted likelihood ratio tests for random and fixed effects based on mixed model analyses of variance. Differences between soil depths and among sites and plots accounted for a large portion of the variation in many soil properties. Litter quality affected soil pH and N mineralization. Earthworm densities affected bulk density, inorganic N content, and N mineralization. Both mycorrhizal groups were more abundant in mature than in successional forests. Both ectomycorrhizal (ECM) and arbuscular (AM) fungi were

  7. Along-axis variability in crustal accretion at the Mid-Atlantic Ridge: Results from the OCEAN study

    USGS Publications Warehouse

    Henstock, T.J.; White, Robert S.; McBride, J.H.

    1996-01-01

    The OCEAN experiment is an integrated geophysical study of a region of the Cape Verde abyssal plain that formed at 140 Ma. Deep seismic reflection and ocean bottom hydrophone (OBH) refraction data were acquired along lines parallel and perpendicular to the paleoridge axis trend identified from a detailed magnetic anomaly survey. The igneous basement is overlain by about 1.3 km of sediment which enables improved imaging of intracrustal structure beyond that possible near the Mid-Atlantic Ridge axis. We describe the results of a 150-km long profile oriented parallel to magnetic anomalies M15 and M16, along which deep seismic reflection data collected by the British Institutions Reflection Profiling Syndicate are complemented by refraction data constrained by four OBHs. The line spans an entire spreading segment between two fracture zones; the northern of which has an offset of 40 km and the other (central) has an offset of only 10 km. Away from the fracture zones, the mean igneous crustal thickness is 7.2 km; near both fracture zones, thinning of up to 4 km is observed, giving a mean igneous crustal thickness over the whole segment of approximately 6.5 km. Differences are seen between the two fracture zones in their seismic velocity structure, in the associated basement topography, and in the presence of a strong reflection extending into the mantle beneath the northern fracture zone. The boundary between oceanic layers 2 and 3 correlates with variably coherent normal incidence reflections and a change in the character of the reflectivity. A number of planar reflections up to 10 km in length are present within the middle and lower crust, dipping outward from beneath low-amplitude basement highs at ??? 15??; these appear to be present only within layer 3. The Moho has several expressions in the reflection data, including isolated reflection events, a local increase in reflected amplitudes, and a downward decrease in coherent reflections. At the center of the segment

  8. Lithospheric Structure, Stress, and Magmatism at the Rainbow Non-Transform Offset on the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Paulatto, M.; Canales, J. P.; Dunn, R. A.

    2014-12-01

    New oceanic lithosphere is formed at slow-spreading mid-ocean ridges by a combination of eruption and intrusion of magma and by tectonic exhumation and alteration of lower crustal and mantle rocks. We look at the relationship between these two processes and how their relative contributions vary at non-transform ridge-segment offsets (NTOs). Models of mantle upwelling predict magmatic input and heat flux to be relatively low at NTOs, yet many host high-temperature hydrothermal systems, which are difficult to explain without the presence of a crustal magmatic source. We analyzed newly acquired swath bathymetry, gravity and magnetic data from the MARINER experiment together with archived data from the Rainbow NTO (36º10' N) on the Mid-Atlantic Ridge. This NTO is currently experiencing both mantle exhumation and magmatic input as evidenced by the active Rainbow high-temperature hydrothermal field. We calculate mantle Bouguer gravity anomalies and crustal magnetization to constrain the lithospheric structure and tectonic evolution of the NTO during the past ~2 Myr. The swath bathymetry data are used to map faults, extrusive volcanic terrain and tectonized blocks and show that the style of crustal accretion varies along the adjacent ridge segments. Spatial changes in the style of extensional faulting are indicative of variations in the mechanical properties and the state of stress of the lithosphere. We suggest that the availability of magma to drive hydrothermal activity at Rainbow and other similar settings is controlled not only by the thermal regime and the structure of the lithosphere but also by the effect of local stress conditions on magma migration. Models of magma migration and dyking show that changes in the direction of minimum compressive stress affect the propagation of magmatic intrusions. We argue that stress rotation can explain the formation of crustal magma chambers at NTOs despite a reduced magmatic flux. These constraints help determine the role of

  9. Styles of Detachment Faulting at the Kane Oceanic Core Complex, 23°N Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Hansen, L. N.; Cheadle, M. J.; John, B. E.; Swapp, S. M.; Dick, H. J.; Tucholke, B. E.; Tivey, M. A.

    2007-12-01

    In 2004, R/V Knorr Cruise 180-2 used ROV Jason II, the autonomous vehicle ABE, and dredges to collect samples and geophysical data from the Kane Oceanic Core Complex (OCC) on the Mid-Atlantic Ridge at 23°N. Examination of the deformed samples by hand-sample analysis, petrography, electron backscatter diffraction, and geothermometry in conjunction with the interpreted bathymetry suggests that the Kane OCC is bound by a detachment fault system that initiated at a moderate to high angle (45-60°), and rooted below the brittle-plastic transition. Constraints on the initial dip of the detachment fault come from the slopes of the ridge forming the breakaway (>23° to the west and >22° to the east). Assuming this ridge formed by flexural uplift, these slopes suggest the detachment fault formed with a dip >45°. Fault rocks, including peridotite mylonites and gabbro ultramylonites, reveal a history of deformation from granulite and amphibolite through sub-greenschist facies including brittle cataclasis. We present two cross sections through the detachment fault and footwall based on samples collected from secondary, high-angle normal faults that cut the detachment. One section, through Cain Dome in the central OCC, is dominated by peridotite and shows a ~450-m thick zone of discrete ductile shear zones with the uppermost portion overprinted by a 200-m zone of semi-brittle and brittle deformation. These are maximum shear zone thicknesses due to the possibility of down-scarp slumping/displacement. The other section, through Adam Dome on the southwest part of the OCC, is dominated by gabbroic rocks and shows little deformation. This section lies <4 km from the breakaway, and is therefore inferred to have undergone only brittle deformation in the shallow crust. A rheologic analysis, using LPO-deduced deformation mechanisms and geothermometry to construct deformation mechanism maps, suggests strain rates for the amphibole-bearing gabbros, the gabbronorites, and the

  10. Off-axis Submarine Massive Sulfide accumulation at the fault-controlled Logatchev 1 hydrothermal field, Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Andersen, Christine; Theissen-Krah, Sonja; Hannington, Mark

    2016-04-01

    The largest Submarine Massive Sulfide (SMS) deposits in Mid-ocean ridge settings are found along slow-spreading ridges, where tectonic processes dominate and long-lived faults control the circulation of hydrothermal fluids through the oceanic crust. Here we combine results from 2D fluid flow simulations of the off-axis (8km), fault-controlled, high-T Logatchev 1 hydrothermal field (LHF1) at the Mid-Atlantic Ridge with data on vent fluid chemistry and the associated SMS deposit, which give insights about its accumulation history. Modeled high vent temperatures of 360°C, as measured at the active LHF1, result in a total integrated mass-flow rate through the seafloor of ~36 kg/sec scaled to 28 vent orifices of 10x10cm, located in the 7 known high-T sites at the LHF1. About 42% of the vent fluids are hotter than 350°C, the minimum temperature required for efficient metal transport, with a mass-flow rate of 13 kg/sec. This corresponds to ~400 kilotons of potentially SMS-forming hydrothermal fluids leaving the vent field per year. Combined with a total H2S-SiO2-metal (Zn+Cu+Fe) concentration of 732 ppm, measured in the LHF1 vent fluids, this makes a flux of ~300 t of hydrothermal precipitates per year. The SMS deposit at LHF1 has been dated to 58.200 years and has an estimated tonnage of 135 kilotons. Applying the above modeled annual discharge rate over the dated time period, results in an SMS accumulation efficiency of ~0.8% for the SMS deposit at the Logatchev 1 field, which fits the range of estimated global average for MORs between <0.3% and 3%. Our predicted depositional efficiency is based on numerical modeling, which simulates continuous and ideal venting. Realistically, venting at LHF1 might well have been fluctuating, including periods of low temperature discharge, where metal transport is insufficient or periods of inactivity, compensated by periods with a higher depositional efficiency than 0.8%. Such fluctuations could have been caused by variations in

  11. Initiation and collapse of active circulation in a hydrothermal system at the Mid-Atlantic Ridge, 23°N

    NASA Astrophysics Data System (ADS)

    Gallinatti, Barbara Cosens

    1984-05-01

    Gabbro and basalt, collected from an area south of the Kane Fracture Zone along the Mid-Atlantic Ridge, have three stages of alteration which record the cooling of a hydrothermal system: (1) Stage 1. Penetration of seawater began between 400° and 550°C, altering pyroxene to fibrous green amphibole. (2) Stage 2. Propylitic alteration formed along connected fractures between 250° and 300°C. As fracture density increased, the Fe/Mg ratio of chlorite increased, the final result being an Fe chlorite-quartz-sulfide breccia. (3) Stage 3. Late smectite veinlets formed at low temperatures (≤200°C) after active circulation ceased The study focuses on stage 2 alteration. By assuming local equilibrium between alteration minerals and the hydrothermal fluid, constraints can be placed on the fluid composition responsible for stage 2 alteration, the stage associated with deposition of sulfides. The following activities of species in solution were determined for the system FeO Na2O-CaO-MgO-Al2O3-SiO2-H2O at 350 bars and 250°C: log a (Ca++)/a2 (H+) = 8.0, log a (Na+)/a (H+) = 5.0, log a (Fe++)/a2 (H+) = 1.7, log a (Mg++)/a2 (H+) = 6.0. Log a (SiO2) was set at quartz saturation (-2.3 at 350 bars and 250°C). Fluid inclusions record the introduction of a low temperature, seawater-salinity fluid during formation of the latest quartz veins associated with stage 2 alteration. Mixing of this and the hydrothermal fluid caused a drop in temperature and increase in oxidation state, resulting in increased precipitation of quartz, pyrite and chalcopyrite. The salinities of fluid inclusions trapped in quartz during stage 2 alteration are as much as 3 times that of seawater. Concentration of a fluid initially of seawater salinity may be the result of boiling at ≥350°C and ≤3000 m depth.

  12. Biodiversity patterns, environmental drivers and indicator species on a high-temperature hydrothermal edifice, Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Sarrazin, Jozée; Legendre, Pierre; de Busserolles, Fanny; Fabri, Marie-Claire; Guilini, Katja; Ivanenko, Viatcheslav N.; Morineaux, Marie; Vanreusel, Ann; Sarradin, Pierre-Marie

    2015-11-01

    Knowledge on quantitative faunal distribution patterns of hydrothermal communities in slow-spreading vent fields is particularly scarce, despite the importance of these ridges in the global mid-ocean system. This study assessed the composition, abundance and diversity of 12 benthic faunal assemblages from various locations on the Eiffel Tower edifice (Lucky Strike vent field, Mid-Atlantic Ridge) and investigated the role of key environmental conditions (temperature, total dissolved iron (TdFe), sulfide (TdS), copper (TdCu) and pH) on the distribution of macro- and meiofaunal species at small spatial scales (<1 m). There were differences in macro- and meiofaunal community structure between the different sampling locations, separating the hydrothermal community of the Eiffel Tower edifice into three types of microhabitats: (1) cold microhabitats characterized by low temperatures (<6 °C), high TdCu (up to 2.4±1.37 μmol l-1), high pH (up to 7.34±0.13) but low TdS concentrations (<6.98±5.01 μmol l-1); (2) warm microhabitats characterized by warmer temperatures (>6 °C), low pH (<6.5) and high TdS/TdFe concentrations (>12.8 μmol l-1/>1.1 μmol l-1 respectively); and (3) the third microhabitat characterized by intermediate abiotic conditions. Environmental conditions showed more variation in the warm microhabitats than in the cold microhabitats. In terms of fauna, the warm microhabitats had lower macro- and meiofaunal densities, and lower richness and Shannon diversity than the cold microhabitats. Six macrofaunal species (Branchipolynoe seepensis, Amathys lutzi, Bathymodiolus azoricus, Lepetodrilus fucensis, Protolira valvatoides and Chorocaris chacei) and three meiofaunal taxa (Paracanthonchus, Cephalochaetosoma and Microlaimus) were identified as being significant indicator species/taxa of particular microhabitats. Our results also highlight very specific niche separation for copepod juveniles among the different hydrothermal microhabitats. Some sampling units

  13. Local Seismicity of the slow-spreading Mid-Atlantic ridge: median valley earthquakes shallow towards segment ends

    NASA Astrophysics Data System (ADS)

    Tilmann, F.; Planert, L.; Flueh, E.; Reston, T.; Weinrebe, W.

    2003-04-01

    Slow spreading mid-ocean ridges are characterized by along-axis segmentation where crustal composition and structure varies significantly within a segment and across transform faults and other ridge axis discontinuities. In May 2000, the GERSHWIN experiment (Geophysical Experiments to investigate Ridge Segmentation HoW INside and outside corners forms) investigated the Mid-Atlantic Ridge (MAR) at 5oS during cruise M47/2 of RV Meteor. The work program included seismic refraction profiling, bathymetric mapping, dredging, and a passive seismological survey, the results of which we are reporting here. In the study area, two spreading segments of the MAR are separated by a 70 km offset transform fault. This segment of the ridge is unusual in that the inside corner high has been split by a change in location of active seafloor spreading. (Reston et al., 2002). Just south of the 5oS transform fault, a network of up to 15 ocean bottom stations (13 hydrophones and 2 seismometers), recorded micro-earthquake activity for a duration of altogether 10 days (because of instrument failures and early recovery instrument numbers vary throughout this period, though). Approximately, 150 earthquakes produced clear arrivals on three or more stations. Approximately half of these events have five or more picks and a azimuthal gap less than 300o, so can be considered well located; 49 events have good depth control. Earthquake activity is concentrated along a narrow zone along the median valley. A few events occur along the transform fault, and in diffuse regions within the Inside Corner High and the bounding massif near the centre of the segment. Event depths vary between 5 and 13 km below sea level (approx. 1-9 km below the seafloor), with most occurring at 7-9 km depth below seafloor. Earthquake depths within the median valley shallow towards the segment end, however, there is no significant seismicity within the immediate neighbourhood of the fracture zone or beneath the volcanic ridge

  14. Selenium and tellurium systematics in MORBs from the southern Mid-Atlantic Ridge (47-50°S)

    NASA Astrophysics Data System (ADS)

    Lissner, M.; König, S.; Luguet, A.; le Roux, P. J.; Schuth, S.; Heuser, A.; le Roex, A. P.

    2014-11-01

    Selenium and tellurium concentrations along with sulfur and Highly Siderophile Element (HSE) contents as well as 187Os signatures were determined in 20 Mid-Ocean-Ridge Basalts (MORBs) from the southern Mid-Atlantic Ridge (SMAR; 47-50°S), ranging in composition from depleted N-MORBs to mantle plume-related E-MORBs. A comparison between glassy rims and crystalline pillow interiors reveal that secondary processes are only reflected in seawater-overprinted 187Os/188Os signatures and degassing-related low S contents of the crystalline pillow cores but did not affect the Se and Te abundances. In contrast, the segregation of sulfide liquids during MORB differentiation lowers the Se and Te concentrations (∼35% and 60%, respectively) and leads to higher Se/Te ratios. Recomputed primitive melt Se contents broadly overlap for both, N- and E-MORBs, while primitive E-MORB melts have systematically higher Te contents and lower Se/Te ratios compared to those of the N-MORBs (13-14 ppb Te and Se/Te ≈ 18 vs. 9-11 ppb Te and Se/Te ≈ 25). As suggested by lithophile trace element and Sr-Nd-Pb isotopic constraints, the Se-Te systematics of the E-MORB mantle source traces the involvement of a recycled component likely derived from the nearby Discovery mantle plume. Bulk mixing models suggests an addition of either 20% pyroxenitic melts, or only 10 ppm of metasomatic sulfides to account for the Te-richer E-MORB compositions. A conservative correction of our MORB data for sulfide segregation combined with a near fractional melting model predicts a Te-depleted MORB mantle reservoir with a non-chondritic Se/Te of 18-25, significantly higher than the primitive mantle Se/Te estimates (6.3-9.9). The existence of these different Se-Te signatures between the E-MORB mantle source, the N-MORB mantle source and the primitive mantle support an incompatible behavior of both Se and Te during partial melting, with Te being slightly more incompatible. More importantly, this stresses the necessity

  15. Hydrothermal alteration and sulfide mineralization in gabbroids of the Markov Deep (Mid-Atlantic Ridge, 6° N)

    NASA Astrophysics Data System (ADS)

    Sharkov, E. V.; Abramov, S. S.; Simonov, V. A.; Krinov, D. I.; Skolotnev, S. G.; Bel'Tenev, V. E.; Bortnikov, N. S.

    2007-12-01

    A new type of sulfide occurrence related to metasomatically altered brecciated gabbroids has been studied at the Sierra Leone site situated in the axial rift valley of the Mid-Atlantic Ridge (Markov Deep, 6° N). Two associations of plutonic, subvolcanic, and volcanic rocks were dredged: (1) mid-ocean ridge basalts (MORB) and their intrusive analogues and (2) rocks of the silicic Fe-Ti-oxide series with dominating gabbronorites and sporadic trondhjemites. Almost all igneous rocks at the Sierra Leone site are enriched in Pb, Cu, U, Ga, Ta, Nb, Cs, and Rb and depleted in Zr, Th, and Hf. The rocks of the Fe-Ti-oxide series are enriched in Zn, Sn, and Mo and depleted in Ni and Cr. The main ore-bearing zone is situated at the foot of the eastern wall of the deep, where it is hosted in cataclastic hornblende gabbro and gabbronorite of the Fe-Ti-oxide series. Ore mineralization in metasomatically altered rocks is composed of quartz-sulfide and prehnite-sulfide veinlets, disseminated sulfide, and veined copper sulfide ore. The ore consists of pyrite, chalcopyrite, sphalerite, pyrrhotite, bornite, chalcocite, and digenite. The δ34S value of sulfides varies from 3.0 to 15.3‰. At the foot of the eastern wall of the Markov Deep, directly downslope from the ore-bearing zone, loose sediments contain grains of native Cu, Pb, Zn, and Sn and intermetallic compounds (isoferroplatinum, tetraferroplatinum, and brass) apparently derived from the ore. Mineral assemblages of ore-bearing metasomatic rocks and fluid inclusions therein were studied. Ore metasomatism developed under a low oxygen potential within a temperature interval from 400 to 160°C, though initial hydrothermal alteration of rocks proceeded at temperatures of 800-450°C. The temperature of stringer-disseminated ore mineralization is estimated at 170-280°C. The hydrothermal fluids are considered to be of magmatic origin; as the hydrothermal system evolved, they became diluted with seawater that was contained in

  16. Dynamic Management of NOx and SO2 Emissions in the Texas and Mid-Atlantic Electric Power Systems and Implications for Air Quality.

    PubMed

    McDonald-Buller, Elena; Kimura, Yosuke; Craig, Michael; McGaughey, Gary; Allen, David; Webster, Mort

    2016-02-01

    Cap and trade programs have historically been designed to achieve annual or seasonal reductions in emissions of nitrogen oxides and sulfur dioxide from power plants. Emissions reductions may not be temporally coincident with meteorological conditions conducive to the formation of peak ozone and fine particulate matter concentrations. Integrated power system and air quality modeling methods were developed to evaluate time-differentiated emissions price signals on high ozone days in the Mid-Atlantic portion of the Pennsylvania-New Jersey-Maryland (PJM) Interconnection and Electric Reliability Council of Texas (ERCOT) grids. Sufficient flexibility exists in the two grids with marked differences in demand and fuel generation mix to accommodate time-differentiated emissions pricing alone or in combination with a season-wide program. System-wide emissions reductions and production costs from time-differentiated pricing are shown to be competitive with those of a season-wide program on high ozone days and would be more cost-effective if the primary policy goal was to target emissions reductions on these days. Time-differentiated pricing layered as a complement to the Cross-State Air Pollution Rule had particularly pronounced benefits for the Mid-Atlantic PJM system that relies heavily on coal-fired generation. Time-differentiated pricing aimed at reducing ozone concentrations had particulate matter reduction co-benefits, but if particulate matter reductions are the primary objective, other approaches to time-differentiated pricing may lead to greater benefits. PMID:26727552

  17. A geochemical study of metalliferous sediment from the TAG Hydrothermal Mound, 26°08‧N, Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    German, C. R.; Higgs, N. C.; Thomson, J.; Mills, R.; Elderfield, H.; Blusztajn, J.; Fleer, A. P.; Bacon, M. P.

    1993-06-01

    An Alvin push core collected near the base of the TAG hydrothermal mound, 26°08'N, Mid-Atlantic Ridge, sampled a 7 cm-thick layer of Fe-rich red-brown mud (20-40% Fe) overlying a 4 cm-thick layer of carbonate ooze (5-70% CaCO3) which also contains up to 32%Fe. On the basis of chemical compositions, two separate layers can be identified within the red-brown mud. The core position, X ray diffractometry, Pb isotope analyses, and elemental abundances all indicate that these two layers were derived from mass wasting of oxidized, originally sulphidic material from the slopes of the TAG hydrothermal mound. High concentrations (11-19 ppm) of seawater-derived U occur in both Fe-rich layers. These enrichments may derive from uptake of U linked to the oxidation of sulphide phases. Metal concentrations in the rich layer are lower than in the upper part of the core but higher than in open ocean pelagic sediments. The 230Thxs/Fe, 231Paxs/Fe, and rare earth element/Fe distributions indicate that the hydrothermal input to the carbonate-rich layer is dominated by settling of suspended particulate material from the overlying hydrothermal plume. Such CaCO3-rich sediments may record an important component of the flux of hydrothermal material to sediments of the Mid-Atlantic Ridge rift valley.

  18. Three-dimensional geometry of axial magma chamber roof and faults at Lucky Strike volcano on the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Combier, Violaine; Seher, Tim; Singh, Satish C.; Crawford, Wayne C.; Cannat, Mathilde; Escartín, Javier; Dusunur, Doga

    2015-08-01

    We present results from three-dimensional (3-D) processing of seismic reflection data, acquired in June 2005 over the Lucky Strike volcano on the Mid-Atlantic Ridge as a part of the Seismic Study for Monitoring of the Mid-Atlantic Ridge survey. We use a 3-D tomographic velocity model derived from a coincident ocean bottom seismometer experiment to depth convert the poststack time-migrated seismic volume and provide 3-D geometry of the axial magma chamber roof, fault reflectors, and layer 2A gradient marker. We also generate a high-resolution bathymetric map using the seismic reflection data. The magma chamber roof is imaged at 3.4 ± 0.4 km depth beneath the volcano, and major faults are imaged with dips ranging between 33° and 50°. The magma chamber roof geometry is consistent with a focused melt supply at the segment center and steep across-axis thermal gradients as indicated by the proximity between the magma chamber and nearby faults. Fault scarps on the seafloor and fault dip at depth indicate that tectonic extension accounts for at least 10% of the total plate separation. Shallow dipping reflectors imaged in the upper crust beneath the volcano flanks are interpreted as buried lava flow surfaces.

  19. Decadal Declines of Mercury in Adult Bluefish (1972-2011) from the Mid-Atlantic Coast of the U.S.A.

    PubMed

    Cross, Ford A; Evans, David W; Barber, Richard T

    2015-08-01

    Concentrations of total mercury were measured in muscle of adult bluefish (Pomatomus saltatrix) collected in 2011 off North Carolina and compared with similar measurements made in 1972. Concentrations of mercury decreased by 43% in the fish between the two time periods, with an average rate of decline of about 10% per decade. This reduction is similar to estimated reductions of mercury observed in atmospheric deposition, riverine input, seawater, freshwater lakes, and freshwater fish across northern North America. Eight other studies between 1973 and 2007 confirm the decrease in mercury levels in bluefish captured in the Mid-Atlantic Bight. These findings imply that (1) reductions in the release of mercury across northern North America were reflected rather quickly (decades) in the decline of mercury in adult bluefish; (2) marine predatory fish may have been contaminated by anthropogenic sources of mercury for over 100 years; and (3) if bluefish are surrogates for other predators in the Mid-Atlantic Bight, then a reduction in the intake of mercury by the fish-consuming public has occurred. Finally, with global emissions of mercury continuing to increase, especially from Asia, it is important that long-term monitoring programs be conducted for mercury in marine fish of economic importance. PMID:26148053

  20. The consequences of landscape change on ecological resources: An assessment of the United States mid-Atlantic region, 1973-1993

    USGS Publications Warehouse

    Jones, K.B.; Neale, A.C.; Wade, T.G.; Wickham, J.D.; Cross, C.L.; Edmonds, C.M.; Loveland, T.R.; Nash, M.S.; Riitters, K.H.; Smith, E.R.

    2001-01-01

    Spatially explicit identification of changes in ecological conditions over large areas is key to targeting and prioritizing areas for environmental protection and restoration by managers at watershed, basin, and regional scales. A critical limitation to this point has been the development of methods to conduct such broad-scale assessments. Field-based methods have proven to be too costly and too inconsistent in their application to make estimates of ecological conditions over large areas. New spatial data derived from satellite imagery and other sources, the development of statistical models relating landscape composition and pattern to ecological endpoints, and geographic information systems (GIS) make it possible to evaluate ecological conditions at multiple scales over broad geographic regions. In this study, we demonstrate the application of spatially distributed models for bird habitat quality and nitrogen yield to streams to assess the consequences of landcover change across the mid-Atlantic region between the 1970s and 1990s. Moreover, we present a way to evaluate spatial concordance between models related to different environmental end-points. Results of this study should help environmental managers in the mid-Atlantic region target those areas in need of conservation and protection.

  1. Time-clustering behavior of spreading-center seismicity between 15 and 35°N on the Mid-Atlantic Ridge: observations from hydroacoustic monitoring

    NASA Astrophysics Data System (ADS)

    Bohnenstiehl, DelWayne R.; Tolstoy, Maya; Smith, Deborah K.; Fox, Christopher G.; Dziak, Robert P.

    2003-07-01

    An earthquake catalog derived from the detection of seismically-generated T-waves is used to study the time-clustering behavior of moderate-size (≳3.0 M) earthquakes between 15 and 35°N along the Mid-Atlantic Ridge (MAR). Within this region, the distribution of inter-event times is consistent with a non-periodic, non-random, clustered process. The highest degrees of clustering are associated temporally with large mainshock-aftershock sequences; however, some swarm-like activity also is evident. Temporal fluctuations characterized by a power spectral density P( f) that decays as 1/ fα are present within the time sequence, with α ranging from 0.12 to 0.55 for different regions of the spreading axis. This behavior is negligible at time scales less than ˜5×10 3 s, and earthquake occurrence becomes less clustered (smaller α) as increasing size thresholds are applied to the catalog. A power-law size-frequency scaling for Mid-Atlantic Ridge earthquakes also can be demonstrated using the distribution of acoustic magnitudes, or source levels. Although fractal seismic behavior has been linked to the structure of the underlying fault population in other environments, power-law fault size distributions have not been observed widely in the mid-ocean ridge setting.

  2. Distribution, population biology, and trophic ecology of the deepwater demersal fish Halosauropsis macrochir (Pisces: Halosauridae) on the mid-Atlantic Ridge.

    PubMed

    Bergstad, Odd Aksel; Clark, Laura; Hansen, Hege Øverbø; Cousins, Nicola

    2012-01-01

    Halosauropsis macrochir ranked amongst the most abundant and widespread demersal fishes on the mid-Atlantic Ridge of the North Atlantic (Iceland-Azores) with greatest abundance at 1700-3500 m. All sizes, ranging from 10-76 cm total length, occurred in the area without any apparent spatial pattern or depth trend. Using otolith sections displaying growth increments assumed to represent annuli, the age range recorded was 2-36 years, but most individuals were <20 years. Length and weight at age data were used to fit growth models. No differences between sexes in length and weight at age were observed. The majority of samples had a surplus of males. Diet analysis showed that H. macrochir feeds on Crustacea, Teleostei, Polychaeta, and Cephalopoda, but few prey could be identified to lower taxonomical levels. The mid-Atlantic Ridge constitutes a major portion of the North Atlantic living space of the abyssal halosaur where it completes its full life cycle, primarily as an actively foraging euryophagous micronekton/epibenthos and infauna feeder, becoming a partial piscivore with increasing size. PMID:22384030

  3. Distribution, Population Biology, and Trophic Ecology of the Deepwater Demersal Fish Halosauropsis macrochir (Pisces: Halosauridae) on the Mid-Atlantic Ridge

    PubMed Central

    Bergstad, Odd Aksel; Clark, Laura; Hansen, Hege Øverbø; Cousins, Nicola

    2012-01-01

    Halosauropsis macrochir ranked amongst the most abundant and widespread demersal fishes on the mid-Atlantic Ridge of the North Atlantic (Iceland-Azores) with greatest abundance at 1700–3500 m. All sizes, ranging from 10–76 cm total length, occurred in the area without any apparent spatial pattern or depth trend. Using otolith sections displaying growth increments assumed to represent annuli, the age range recorded was 2–36 years, but most individuals were <20 years. Length and weight at age data were used to fit growth models. No differences between sexes in length and weight at age were observed. The majority of samples had a surplus of males. Diet analysis showed that H. macrochir feeds on Crustacea, Teleostei, Polychaeta, and Cephalopoda, but few prey could be identified to lower taxonomical levels. The mid-Atlantic Ridge constitutes a major portion of the North Atlantic living space of the abyssal halosaur where it completes its full life cycle, primarily as an actively foraging euryophagous micronekton/epibenthos and infauna feeder, becoming a partial piscivore with increasing size. PMID:22384030

  4. MoMar-Demo at Lucky Strike. A near-real time multidisciplinary observatory of hydrothermal processes and ecosystems at the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Cannat, M.; Sarradin, P.; Blandin, J.; Escartin, J.; Colaco, A.; MoMAR-Demo Scientific Party : Aron Michael, Aumont Virginie, Baillard Christian, Ballu Valérie, Barreyre Thibaut, Blandin Jérôme, Blin Alexandre, Boulart Cédric, Cannat Mathilde, Carval Thierry, Castillo Alain, Chavagnac Valérie, Coail Jean Yves, Colaço Ana, Corela Carlos, Courrier Christophe, Crawford Wayne, Cuvelier Daphné, Daniel Romuald, Dausse Denis, Escartin Javier, Fabrice Fontaine, Gabsi Taoufik, Gayet Nicolas, Guyader Gérard, Lallier François, Lecomte Benoit, Legrand Julien, Lino Silva, Miranda Miguel, Mitard Emmelyne, Pichavant Pascal, Pot Olivier, Reverdin Gilles, Rommevaux Céline, Sarradin Pierre Marie, Sarrazin Jozée, Tanguy Virginie, Villinger Heinrich, Zbinden Magali

    2011-12-01

    The MoMAR "Monitoring the Mid-Atlantic Ridge" project was initiated by InterRidge in 1998 to study the environmental instability resulting from active mid-ocean-ridge processes at hydrothermal vent fields south of the Azores. It then developped into a component of the ESONET (European Seafloor Observatory Network) and EMSO (European Multidisciplinary Subsea Observatory) programs, which coordinate eulerian observatory initiatives in the seas around Europe. MoMAR experiments have started in 2006 and address two main questions : What are the feedbacks between volcanism, deformation, seismicity, and hydrothermalism at a slow spreading mid-ocean ridge? and How does the hydrothermal ecosystem couple with these sub-seabed processes? The MoMAR-Demo project started in 2010 with partial support from ESONET. It has been implemented so far by 2 cruises of the RV Pourquoi Pas ? during which we successfully deployed (in 2010), and upgraded (in 2011) a near-realtime buoyed observatory system. The system comprises two Sea Monitoring Nodes (SeaMoN) at the seafloor, which are acoustically linked to a surface relay buoy (BoRel), ensuring satellite communication to a land base station in Brest (France). One SeaMoN node connects to a 3-components seismometer and an hydrophone for seismic event detection, and two pressure probes for geodetic measurements, and the other SeaMoN node connects to a video camera, a dissolved-iron analyzer, and an optode (oxygen and temperature probe) for ecological time studies. The BOREL transmission buoy is equiped with GPS (geodetic experiment and buoy location) and meteo station. Data and/or status signals from these sensors are transmitted every 6 hours, and put on line in compliance with the ESONET-EMSO data policy (temporary access through http://www.ifremer.fr/WC2en/allEulerianNetworks). The MoMAR-Demo system also allows for interactive connections and changes of data transmission rates on demand. It is nested in arrays of autonomous sensors (OBSs

  5. Characterization of dissolved organic matter (DOM) for a mid-Atlantic Piedmont forested watershed using multivariate analyses

    NASA Astrophysics Data System (ADS)

    Singh, S.; Inamdar, S. P.

    2011-12-01

    Understanding the biotic and abiotic mechanisms of DOM solubilization and immobilization in forested ecosystem have important implications to comprehend present and future carbon budgets. In this study, DOM concentrations and compositions were investigated for a mid-Atlantic Piedmont forested watershed using excitation-emission matrices (EEMs) fluorescence combined with parallel factor analysis (PARAFAC). Samples were collected across wide sources including throughfall, litter, soils , wetlands, streams, hyproheic, seeps, shallow, riparian, and deep groundwaters, over a two year period (2008-2009) during baseflow conditions. A site specific PARAFAC model was developed to evaluate DOM characteristics, resulted in six diverse DOM compositions, which include, two terrestrial humic-like (component 1 and 4), one soil derived humic-like (component 3), one non-humic like (component 2), and two protein-like (component 5 and 6) components. Component 1 and 3 showed a decreasing trend from surface (litter, throughfall, wetlands), with an exception in soils, to subsurface layers with a high variability in riparian, shallow, and deep ground waters in addition to seep locations . Component 2, an indicator of biologically labile organic matter, showed a larger variability in subsurface sources, with a highest value at seep locations, in comaprison to surface sources. The observed median values for component 4 (visible-humic-like,) was highest in soils (0.14 RU) and lowest in deep groundwaters (0.08 RU). In contrast to component 1 and 3, component 5 and 6 (indicator of protein-like moieties) were significantly higher in subsurface sources (riparian, seep, and deep groundwaters). Median values for components 5 ranged from 0.09 to 0.33 RU, whereas the same for component 6 ranged from 0.02 to 0.76 RU (litter and deep groundwaters, respectively). Other optical DOM metrics were generated including a254, SUVA254, UV253/203, HIX, FI, alongwith DOC concentrations, across all watershed

  6. Patterns and contributions of floodplain and legacy sediments remobilized from Piedmont streams of the mid-Atlantic U.S.

    NASA Astrophysics Data System (ADS)

    Donovan, Mitchell; Miller, Andrew; Baker, Matthew; Gellis, Allen

    2015-04-01

    The perceived role of streambank erosion as a contributor to watershed sediment yield is an important driver of policy decisions for managing downstream impacts in the United States. In the Piedmont physiographic province of the eastern U.S. and in other regions of the south and midwest, the issue of 'legacy' sediment stored in stream valleys has long been recognized as a consequence of rapid deforestation and erosive agricultural practices following European settlement. Remobilization of stored floodplain sediment by bank erosion is frequently cited as a dominant component of watershed sediment budgets, with legacy sediment comprising the largest portion of this source. However there are few published studies documenting spatially extensive measurements of channel change throughout the drainage network on time scales of more than a few years. In this study we document 1) rates of sediment remobilization from Baltimore County floodplains by channel migration and bank erosion, 2) proportions of streambank sediment derived from legacy deposits, and 3) potential contribution of net streambank erosion and legacy sediments to downstream sediment yield within the Mid-Atlantic Piedmont. We measured gross erosion and channel deposition rates over 45 years within the fluvial corridor along 40 valley segments from 18 watersheds with drainage areas between 0.18 and 155 km2 by comparing stream channel and floodplain morphology from LiDAR-based digital elevation data collected in 2005 with channel positions recorded on 1:2400-scale topographic maps from 1959-1961. Results were extrapolated to estimate contributions to watershed sediment yield from 1005 km2 of northern Baltimore County. Results indicate that legacy sediment is a dominant component (62%) of the sediment derived from bank erosion and that its relative importance is greater in larger valleys with broader valley floors and lower gradients. Although mass of sediment remobilized per unit channel length is greater in

  7. Plume or Mantle Heterogeneity? Numerical Modeling of the Mid-Atlantic Ridge between 2°-14°S

    NASA Astrophysics Data System (ADS)

    Hasenclever, J.; Hort, M. K.; Phipps-Morgan, J.

    2009-12-01

    The ˜900 km long section of the Mid-Atlantic ridge (MAR) between 2°-14°S is a study area of the German priority program SPP 1144, and has been the site of several ship cruises since 2004. Ridge morphology, ridge axis bathymetry, and crustal thickness vary considerably along this part of the MAR, several large- and small-offset fracture zones displace the ridge axis by up to 250 km. The most prominent (and mostly unexplained) geodynamic features are the active volcanic island of Ascension, located 80 km west of the MAR, and a melting anomaly beneath the MAR at 9°30'S causing an elevated ridge axis without axial valley, with crustal thicknesses of up to 11 km, and large seamounts. Possible explanations are enhanced melting of a mantle heterogeneity or the influence of a weak mantle plume located either close to the ridge axis or beneath the Circe seamount (˜450 km east of the MAR). By numerically modeling the different scenarios we test their feasibility in terms of mantle flow and melting. We use a self-developed parallel 3D finite element MATLAB code to numerically solve for viscous flow, advection and diffusion of heat, and melting of a multi-component mantle, discretized on unstructured tetrahedra meshes. The velocity-pressure formulation is based on Maday and Patera [State of the Art Surveys in Computational Mechanics, 1989] and solved using a multigrid-preconditioned conjugate gradient algorithm. Advection of temperature and compositional fields is achieved by a semi-Lagrange Predictor-Corrector scheme combined with bi-cubic interpolation on the unstructured mesh. Diffusion of heat is solved using standard operator-splitting methods and a conjugate gradient algorithm. The melting formulation is based on Phipps Morgan [G3, 2001], to which we added the effect of source water using the parameterization of Katz et al. [G3, 2004]. We include the buoyancy effects of Fe-depletion and melt in pores, and assume a rheology that depends on depth, temperature, water

  8. Magmatic ^18O in Zircons From Gabbros and Serpentinized Peridotite at the Mid-Atlantic Ridge (ODP Leg 153)

    NASA Astrophysics Data System (ADS)

    Cavosie, A. J.; Kita, N. T.; Valley, J. W.

    2005-12-01

    Zircons from gabbros and serpentinized ultramafic rocks from the Mid-Atlantic Ridge near the Kane Transform (MARK area) drilled during Leg 153 of the Ocean Drilling Program were analyzed for δ18O in situ in rock chips by ion microprobe. The gabbros contain clinopyroxene, plagioclase, apatite, Fe-oxides, with zircon occurring primarily along grain boundaries and as inclusions in other minerals (e.g. plagioclase). The mineralogy of the serpentinites is more complex, as they are comprised predominantly of a serpentine matrix that is cross-cut by multiple generations of intrusions, including zircon-bearing magmas emplaced as cm- to mm-scale gabbroic dikes and also lower temperature hydrothermal veins. The gabbroic dikes were pervasively altered at greenschist facies conditions, leaving zircon ± apatite as the only preserved magmatic phases. In some serpentinites it is difficult to distinguish altered magmatic veins from lower temperature hydrothermal veins. Zircons in serpentinite and gabbroic samples yield average δ18O values of 4.94±0.80‰ VSMOW (2 SD, N=33 analyses on 12 grains). This value would be in high temperature, magmatic equilibrium with MORB if δ18O (WR) ~ 5.3‰, or mantle peridotite if δ18O (Ol) = ~4.8‰. Equilibrium fractionation factors for δ18O between zircon-water (Zrc-H2O) were calculated by combining fractionation factors for Zrc-quartz (Valley et al. 2003) and quartz-H2O (Clayton et al., 1972; Matsuhisa et al., 1979). Over the temperature range of the calibrated fractionation factors (i.e. 500-800°C), calculated δ18O (zircon) values would be < 1 ‰ for zircon in equilibrium with previously measured MARK hydrothermal fluids (e.g. δ18O = 2.3‰). Zircon in equilibrium with seawater with δ18O = 0.0‰ would have 2.3‰ lower values. We note that extrapolation of the Zrc-H2O fractionation factors to temperatures below the calibrations of Zrc-Qtz and Qtz-H2O (e.g. <500°C) does not yield a typical mineral-water `crossover' at lower

  9. Microbial iron mats at the Mid-Atlantic Ridge and evidence that Zetaproteobacteria may be restricted to iron-oxidizing marine systems.

    PubMed

    Scott, Jarrod J; Breier, John A; Luther, George W; Emerson, David

    2015-01-01

    Chemolithoautotrophic iron-oxidizing bacteria play an essential role in the global iron cycle. Thus far, the majority of marine iron-oxidizing bacteria have been identified as Zetaproteobacteria, a novel class within the phylum Proteobacteria. Marine iron-oxidizing microbial communities have been found associated with volcanically active seamounts, crustal spreading centers, and coastal waters. However, little is known about the presence and diversity of iron-oxidizing communities at hydrothermal systems along the slow crustal spreading center of the Mid-Atlantic Ridge. From October to November 2012, samples were collected from rust-colored mats at three well-known hydrothermal vent systems on the Mid-Atlantic Ridge (Rainbow, Trans-Atlantic Geotraverse, and Snake Pit) using the ROV Jason II. The goal of these efforts was to determine if iron-oxidizing Zetaproteobacteria were present at sites proximal to black smoker vent fields. Small, diffuse flow venting areas with high iron(II) concentrations and rust-colored microbial mats were observed at all three sites proximal to black smoker chimneys. A novel, syringe-based precision sampler was used to collect discrete microbial iron mat samples at the three sites. The presence of Zetaproteobacteria was confirmed using a combination of 16S rRNA pyrosequencing and single-cell sorting, while light micros-copy revealed a variety of iron-oxyhydroxide structures, indicating that active iron-oxidizing communities exist along the Mid-Atlantic Ridge. Sequencing analysis suggests that these iron mats contain cosmopolitan representatives of Zetaproteobacteria, but also exhibit diversity that may be uncommon at other iron-rich marine sites studied to date. A meta-analysis of publically available data encompassing a variety of aquatic habitats indicates that Zetaproteobacteria are rare if an iron source is not readily available. This work adds to the growing understanding of Zetaproteobacteria ecology and suggests that this organism

  10. Microbial Iron Mats at the Mid-Atlantic Ridge and Evidence that Zetaproteobacteria May Be Restricted to Iron-Oxidizing Marine Systems

    PubMed Central

    Scott, Jarrod J.; Breier, John A.; Luther, George W.; Emerson, David

    2015-01-01

    Chemolithoautotrophic iron-oxidizing bacteria play an essential role in the global iron cycle. Thus far, the majority of marine iron-oxidizing bacteria have been identified as Zetaproteobacteria, a novel class within the phylum Proteobacteria. Marine iron-oxidizing microbial communities have been found associated with volcanically active seamounts, crustal spreading centers, and coastal waters. However, little is known about the presence and diversity of iron-oxidizing communities at hydrothermal systems along the slow crustal spreading center of the Mid-Atlantic Ridge. From October to November 2012, samples were collected from rust-colored mats at three well-known hydrothermal vent systems on the Mid-Atlantic Ridge (Rainbow, Trans-Atlantic Geotraverse, and Snake Pit) using the ROV Jason II. The goal of these efforts was to determine if iron-oxidizing Zetaproteobacteria were present at sites proximal to black smoker vent fields. Small, diffuse flow venting areas with high iron(II) concentrations and rust-colored microbial mats were observed at all three sites proximal to black smoker chimneys. A novel, syringe-based precision sampler was used to collect discrete microbial iron mat samples at the three sites. The presence of Zetaproteobacteria was confirmed using a combination of 16S rRNA pyrosequencing and single-cell sorting, while light micros-copy revealed a variety of iron-oxyhydroxide structures, indicating that active iron-oxidizing communities exist along the Mid-Atlantic Ridge. Sequencing analysis suggests that these iron mats contain cosmopolitan representatives of Zetaproteobacteria, but also exhibit diversity that may be uncommon at other iron-rich marine sites studied to date. A meta-analysis of publically available data encompassing a variety of aquatic habitats indicates that Zetaproteobacteria are rare if an iron source is not readily available. This work adds to the growing understanding of Zetaproteobacteria ecology and suggests that this organism

  11. Nitrogen fluxes in response to changing NOx emissions and deposition at EPA's Mid-Atlantic Long Term Monitoring (LTM) stream sites, 1990-2009

    NASA Astrophysics Data System (ADS)

    Funk, C.; Lynch, J. A.

    2012-12-01

    Surface water chemistry provides direct indicators of the potential effects of anthropogenic impacts, such as acid deposition and climate change, on the overall health of aquatic ecosystems. Long-term surface water monitoring networks provide a host of environmental data that can be used, in conjunction with other networks, to assess how water bodies respond to stressors and if they are potentially at risk (e.g., receiving pollutant deposition beyond its critical load). Two EPA-administered monitoring programs provide information on the effects of acidic deposition on headwater aquatic systems: the Temporally Integrated Monitoring of Ecosystems (TIME) program and Long Term Monitoring (LTM) program, designed to track the effectiveness of the 1990 Clean Air Act Amendments (CAAA) in reducing the acidity of surface waters in the Northeast and Mid-Atlantic. Here we compare trends in inorganic nitrogen emissions and deposition to streamwater nitrate (NO3-) concentration trends and NO3- export in headwater Mid-Atlantic streams. Annual NOx emissions from the fossil fuel based power sector, regulated under Title IV of the 1990 CAAA, decreased 67% from 6.7 million tones in 1990 to 2.0 million tones in 2009. Commensurate with decreased NOx emissions, there was a 31% reduction in total inorganic nitrogen deposition in the Mid-Atlantic region, from 8.7 kg N/ha to 6.0 kg N/yr. Over the same time period, surface water nitrate concentrations in headwater streams in the Northern Appalachian Plateau (n=9) and Central Appalachian mountains (n=66) improve (show a decreasing NO3- trend) at 30% and 50% of monitored sites, respectively. Despite these improvements, only 10% of monitored Appalachian streams show improvement in critical load status to no longer exceed the acid sensitivity threshold and experience adverse ecological effects. Information from long-term monitoring has shown that emission reductions have in improved environmental conditions and increased ecosystem protection

  12. Small-scale distribution of deep-sea demersal nekton and other megafauna in the Charlie-Gibbs Fracture Zone of the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Felley, J. D.; Vecchione, M.; Wilson, R. R., Jr.

    2008-01-01

    Videotapes from manned submersibles diving in the area of the Charlie-Gibbs Fracture Zone of the Mid-Atlantic Ridge were used to investigate the distribution of fishes, large crustaceans, epifaunal and sessile organisms, and environmental features along a series of transects. Submersibles MIR 1 and MIR 2 conducted paired dives in an area of mixed sediment and rock (beginning depth ca. 3000 m) and on a large pocket of abyssal-like sediments (depth ca. 4000 m). In the shallower area, the submersibles passed over extremely heterogeneous terrain with a diversity of nekton, epifaunal forms and sessile forms. In the first pair of dives, MIR 1 rose along the Mid-Atlantic Ridge from 3000 to 1700 m, while MIR 2 remained near the 3000 m isobath. Nekton seen in these relatively shallow dives included large and small macrourids (genus Coryphaenoides), shrimp (infraorder Penaeidea), Halosauropsis macrochir, Aldrovandia sp., Antimora rostrata, and alepocephalids. The last two were more characteristic of the upper areas of the slope reached by MIR 1, as it rose along the Mid-Atlantic Ridge to depths less than 3000 m. Distributions of some forms seemed associated with depth and/or the presence of hard substrate. Sessile organisms such as sponges and large cnidaria were more likely to be found in rocky areas. The second pair of dives occurred in an abyssal area and the submersibles passed over sediment-covered plains, with little relief and many fewer countable organisms and features. The most evident of these were holes, mounds, small cerianthid anemones, small macrourids and the holothurian Benthodytes sp. A few large macrourids and shrimp also were seen in these deeper dives, as well as squat lobsters ( Munidopsis sp.). Sponges and larger cnidaria were mostly associated with a few small areas of rocky substrate. Holes and mounds showed distributions suggesting large-scale patterning. Over all dives, most sessile and epifaunal forms showed clumped distributions. However, large

  13. Sea floor cycling of organic matter in the continental margin of the mid-Atlantic Bight. Final report, May 1, 1995--April 30, 1998

    SciTech Connect

    Jahnke, R.A.

    1998-12-31

    The objective of this project was to examine quantitatively the cycling of organic matter at the sea floor of the mid-Atlantic Bight continental margin. This information would be used to better understand sedimentary geochemical processes and, when used in conjunction with other measurements made within the DOE Ocean Margins Program, would be used to constrain the offshore and surface-to-deep water transport of organic carbon in this region. The latter information is critical in assessing the role of continental margins in the sequestration of anthropogenic carbon dioxide, the dominant greenhouse gas, in the deep ocean. Because the build-up of greenhouse gases in the atmosphere may cause significant changes in climate, this project had major societal importance.

  14. Morphological and karyotypic differentiation in Caranx lugubris (Perciformes: Carangidae) in the St. Peter and St. Paul Archipelago, mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Jacobina, Uedson Pereira; Martinez, Pablo Ariel; Cioffi, Marcelo de Bello; Garcia, José; Bertollo, Luiz Antonio Carlos; Molina, Wagner Franco

    2014-03-01

    Isolated oceanic islands constitute interesting model systems for the study of colonization processes, as several climatic and oceanographic phenomena have played an important role in the history of the marine ichthyofauna. The present study describes the presence of two morphotypes of Caranx lugubris, in the St. Peter and St. Paul Archipelago located in the mid-Atlantic. Morphotypes were compared in regard to their morphological and cytogenetic patterns, using C-banding, Ag-NORs, staining with CMA3/DAPI fluorochromes and chromosome mapping by dual-color FISH analysis with 5S rDNA and 18S rDNA probes. We found differences in chromosome patterns and marked divergence in body patterns which suggest that different populations of the Atlantic or other provinces can be found in the Archipelago of St. Peter and St. Paul.

  15. Hydrothermal circulation, serpentinization, and degassing at a rift valley-fracture zone intersection: Mid-Atlantic Ridge near 15[degree]N, 45[degree]W

    SciTech Connect

    Rona, P.A.; Nelson, T.A. ); Bougault, H.; Charlou, J.L.; Needham, H.D. ); Appriou, P. ); Trefry, J.H. ); Eberhart, G.L.; Barone, A. )

    1992-09-01

    A hydrothermal system characterized by high ratios of methane to both manganese and suspended particulate matter was detected in seawater sampled at the eastern intersection of the rift valley of the Mid-Atlantic Ridge with the Fifteen-Twenty Fracture Zone. This finding contrasts with low ratios in black smoker-type hydrothermal systems that occur within spreading segments. Near-bottom water sampling coordinated with SeaBeam bathymetry and camera-temperature tows detected the highest concentrations of methane at fault zones in rocks with the appearance of altered ultramafic units in a large dome that forms part of the inside corner high at the intersection. The distinct chemical signatures of the two types of hydrothermal systems are inferred to be controlled by different circulation pathways related to reaction of seawater primarily with ultramafic rocks at intersections of spreading segments with fracture zones but with mafic rocks within spreading segments.

  16. A new species of Comephoronema (Nematoda: Cystidicolidae) from the stomach of the abyssal halosaur Halosauropsis macrochir (Teleostei) from the Mid-Atlantic Ridge.

    PubMed

    Moravec, Frantisek; Klimpel, Sven

    2007-08-01

    A new species of parasitic nematode Comephoronema macrochiri n. sp. (Cystidicolidae), is described from the stomach of the marine deep-sea fish Halosauropsis macrochir (abyssal halosaur) from the Mid-Atlantic Ridge (MAR). The new species, studied with both light and scanning electron microscopy, is characterized mainly by 6 pairs of preanal papillae, by which it principally differs from members of Ascarophis; the spicules are 297-375 microm and 99-120 microm long and fully developed eggs possess 2 long filaments on 1 pole. Rhabdochona beatriceinsleyae is transferred to Comephoronema as C. beatriceinsleyae (Holloway and Klewer, 1969) n. comb. Comephoronema macrochiri differs from all other congeners mainly in having eggs with filaments on 1 pole only, and from individual species by some additional features such as the number of preanal papillae, the shape of pseudolabial projections, and the body and organ measurements. PMID:17918373

  17. The national assessment of shoreline change: A GIS compilation of vector shorelines and associated shoreline change data for the New England and Mid-Atlantic Coasts

    USGS Publications Warehouse

    Himmelstoss, Emily A.; Kratzmann, Meredith; Hapke, Cheryl; Thieler, E. Robert; List, Jeffrey

    2010-01-01

    Sandy ocean beaches are a popular recreational destination, often surrounded by communities containing valuable real estate. Development is on the rise despite the fact that coastal infrastructure is subjected to flooding and erosion. As a result, there is an increased demand for accurate information regarding past and present shoreline changes. The U.S. Geological Survey's National Assessment of Shoreline Change Project has compiled a comprehensive database of digital vector shorelines and shoreline-change rates for the New England and Mid-Atlantic Coasts. There is currently no widely accepted standard for analyzing shoreline change. Existing measurement and rate-calculation methods vary from study to study and preclude combining results into statewide or regional assessments. The impetus behind the National Assessment project was to develop a standardized method that is consistent from coast to coast for measuring changes in shoreline position. The goal was to facilitate the process of periodically and systematically updating the results in an internally consistent manner.

  18. Local and regional contributions of fine particulate mass to urban areas in the Mid-Atlantic and Southwestern US. Report for November 1997--September 1998

    SciTech Connect

    Schichtel, B.A.

    1999-03-29

    This work examined the seasonal local and regional contributions of PM2.5 to urban areas in the Mid-Atlantic States: Baltimore, MD, Washington, DC, and Philadelphia, PA and Phoenix, AZ in the Southwest. This was accomplished using two different methods. The first method estimated urban excesses by comparing seasonal PM2.5 trends at the urban monitors to nearby rural monitors. The second approach used a simple model based on the PM2.5 dependence on wind speed and wind direction to classify a site as being dominated by local or regional source contributions. The method also quantifies the regional contributions during high wind speed conditions. The wind vectors were derived from surface observations and air mass histories. All monitoring sites in the urban centers were dominated by local sources during the cold season.

  19. Biodiversity and degradation potential of oil-degrading bacteria isolated from deep-sea sediments of South Mid-Atlantic Ridge.

    PubMed

    Gao, Xiangxing; Gao, Wei; Cui, Zhisong; Han, Bin; Yang, Peihua; Sun, Chengjun; Zheng, Li

    2015-08-15

    The indigenous oil-degrading bacterial consortia MARA and MARB were enriched from the deep-sea sediments of South Mid-Atlantic Ridge (MAR) with crude oil as sole carbon and energy sources. Biodiversity and community analyses showed that members of α-Proteobacteria were the key players in consortium MARA, whereas those of γ-Proteobacteria were the key players in consortium MARB, which were studied by MiSeq sequencing method. Gravimetric method estimated the oil degradation rates of MARA and MARB to be 63.4% and 85.8%, respectively, after 20d. Eleven cultivable oil degraders with different morphologies were isolated. These strains were identified as Alcanivorax, Bacillus, Dietzia, Erythrobacter, Marinobacter, Nitratireductor, and Oceanicola based on 16S rRNA gene sequences. Three strains belonging to Dietzia exhibited the highest oil degradation capability. Results indicated that the intrinsic biodegradation capacity of oil contaminants by indigenous microbial communities exists in South MAR sediments. PMID:26077158

  20. Quantification of the effects of eustasy, subsidence, and sediment supply on Miocene sequences, mid-Atlantic margin of the United States

    USGS Publications Warehouse

    Browning, J.V.; Miller, K.G.; McLaughlin, P.P.; Kominz, M.A.; Sugarman, P.J.; Monteverde, D.; Feigenson, M.D.; Hernandez, J.C.

    2006-01-01

    We use backstripping to quantify the roles of variations in global sea level (eustasy), subsidence, and sediment supply on the development of the Miocene stratigraphic record of the mid-Atlantic continental margin of the United States (New Jersey, Delaware, and Maryland). Eustasy is a primary influence on sequence patterns, determining the global template of sequences (i.e., times when sequences can be preserved) and explaining similarities in Miocene sequence architecture on margins throughout the world. Sequences can be correlated throughout the mid-Atlantic region with Sr-isotopic chronology (??0.6 m.y. to ??1.2 m.y.). Eight Miocene sequences correlate regionally and can be correlated to global ??18O increases, indicating glacioeustatic control. This margin is dominated by passive subsidence with little evidence for active tectonic overprints, except possibly in Maryland during the early Miocene. However, early Miocene sequences in New Jersey and Delaware display a patchwork distribution that is attributable to minor (tens of meters) intervals of excess subsidence. Backstripping quantifies that excess subsidence began in Delaware at ca. 21 Ma and continued until 12 Ma, with maximum rates from ca. 21-16 Ma. We attribute this enhanced subsidence to local flexural response to the progradation of thick sequences offshore and adjacent to this area. Removing this excess subsidence in Delaware yields a record that is remarkably similar to New Jersey eustatic estimates. We conclude that sea-level rise and fall is a first-order control on accommodation providing similar timing on all margins to the sequence record. Tectonic changes due to movement of the crust can overprint the record, resulting in large gaps in the stratigraphic record. Smaller differences in sequences can be attributed to local flexural loading effects, particularly in regions experiencing large-scale progradation. ?? 2006 Geological Society of America.