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Sample records for africa northeastern atlantic

  1. Bipolar seesaw in the northeastern tropical Atlantic during Heinrich stadials

    NASA Astrophysics Data System (ADS)

    Zarriess, Michelle; Johnstone, Heather; Prange, Matthias; Steph, Silke; Groeneveld, Jeroen; Mulitza, Stefan; Mackensen, Andreas

    2011-02-01

    Two SST records based on Mg/Ca of G. ruber (pink) from the continental slope off West Africa at 15°N and 12°N shed new light on the thermal bipolar seesaw pattern in the northeastern tropical Atlantic during periods of reduced Atlantic Meridional Overturning Circulation (AMOC) associated with Heinrich stadials H1 to H6. The two records indicate that the latitudinal position of the bipolar seesaw's zero-anomaly line, between cooling in the North and warming in the South, gradually shifted southward from H6 to H1. A conceptual model is presented that aims to provide a physically consistent mechanism for the southward migration of the seesaw's fulcrum. The conceptual model suggests latitudinal movements of the Intertropical Convergence Zone, driven by a combination of orbital-forced changes in the meridional temperature gradient within the realm of the Hadley cell and the expansion of the Northern Hemisphere cryosphere, as a major factor.

  2. Atlantic marginal basins of Africa

    SciTech Connect

    Moore, G.T.

    1988-02-01

    The over 10,000-km long Atlantic margin of Africa is divisible into thirty basins or segments of the margin that collectively contain over 18.6 x 10/sup 6/ km/sup 3/ of syn-breakup and post-breakup sediments. Twenty of these basins contain a sufficiently thick volume of sediments to be considered prospects. These basins lie, at least partially, within the 200 m isobath. The distribution of source rocks is broad enough to give potential to each of these basins. The sedimentation patterns, tectonics, and timing of events differ from basin to basin and are related directly to the margin's complex history. Two spreading modes exist: rift and transform. Rifting dates from Late Triassic-Early Jurassic in the northwest to Early Cretaceous south of the Niger Delta. A complex transform fault system separated these two margins. Deep-water communication between the two basins became established in the middle Cretaceous. This Mesozoic-Cenozoic cycle of rifting and seafloor spreading has segmented the margin and where observable, basins tend to be bounded by these segments.

  3. 77 FR 65498 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Adjustment to the Atlantic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-29

    ... (75 FR 48874, August 12, 2010). Due to an over-harvest in Area 1A in 2010, the FY 2012 sub-ACL in Area 1A was revised to 24,668 mt on February 24, 2012 (77 FR 10978, February 24, 2012). An additional 295... Northeastern United States; Atlantic Herring Fishery; Adjustment to the Atlantic Herring Management Area 1A...

  4. Atlantic and indian oceans pollution in africa

    NASA Astrophysics Data System (ADS)

    Abubakar, Babagana

    Africa is the second largest and most populated continent after Asia. Geographically it is located between the Atlantic and Indian Oceans. Most of the Africa's most populated and industrialized cities are located along the coast of the continent facing the Atlantic and Indian Oceans, example of such cities include Casablanca, Dakar, Accra, Lagos, Luanda and Cape town all facing the Atlantic Ocean and cities like East London, Durban, Maputo, Dar-es-salaam and Mogadishu are all facing the Indian Ocean. As a result of the geographical locations of African Coastal Cities plus increase in their population, industries, sea port operations, petroleum exploration activities, trafficking of toxic wastes and improper waste management culture lead to the incessant increase in the pollution of the two oceans. NATURE OF POLLUTION OF THE ATLANTIC OCEAN i. The petroleum exploration activities going on along the coast of "Gulf of Guinea" region and Angola continuously causes oil spillages in the process of drilling, bunkering and discharging of petroleum products in the Atlantic Ocean. ii. The incessant degreasing of the Sea Ports "Quay Aprons" along the Coastal cities of Lagos, Luanda, Cape Town etc are continuously polluting the Atlantic Ocean with chemicals. iii. Local wastes generated from the houses located in the coastal cities are always finding their ways into the Atlantic Ocean. NATURE OF POLLUTION OF THE INDIAN OCEAN i. Unlike the Atlantic ocean where petroleum is the major pollutant, the Indian Ocean is polluted by Toxic / Radioactive waste suspected to have been coming from the developed nations as reported by the United Nations Environmental Programme after the Tsunami disaster in December 2004 especially along the coast of Somalia. ii. The degreasing of the Quay Aprons at Port Elizabeth, Maputo, Dar-es-Salaam and Mongolism Sea Ports are also another major source polluting the Indian Ocean. PROBLEMS GENERATED AS A RESULT OF THE OCEANS POLLUTION i. Recent report

  5. Atlantic and Indian Oceans Pollution in Africa

    NASA Astrophysics Data System (ADS)

    Abubakar, B.

    2007-05-01

    Africa is the second largest and most populated continent after Asia. Geographically it is located between the Atlantic and Indian Oceans. Most of the Africa's most populated and industrialized cities are located along the coast of the continent facing the Atlantic and Indian Oceans, example of such cities include Casablanca, Dakar, Accra, Lagos, Luanda and Cape town all facing the Atlantic Ocean and cities like East London, Durban, Maputo, Dar-es-salaam and Mogadishu are all facing the Indian Ocean. As a result of the geographical locations of African Coastal Cities plus increase in their population, industries, sea port operations, petroleum exploration activities, trafficking of toxic wastes and improper waste management culture lead to the incessant increase in the pollution of the two oceans. NATURE OF POLLUTION OF THE ATLANTIC OCEAN i. The petroleum exploration activities going on along the coast of "Gulf of Guinea" region and Angola continuously causes oil spillages in the process of drilling, bunkering and discharging of petroleum products in the Atlantic Ocean. ii. The incessant degreasing of the Sea Ports "Quay Aprons" along the Coastal cities of Lagos, Luanda, Cape Town etc are continuously polluting the Atlantic Ocean with chemicals. iii. Local wastes generated from the houses located in the coastal cities are always finding their ways into the Atlantic Ocean. NATURE OF POLLUTION OF THE INDIAN OCEAN i. Unlike the Atlantic ocean where petroleum is the major pollutant, the Indian Ocean is polluted by Toxic / Radioactive waste suspected to have been coming from the developed nations as reported by the United Nations Environmental Programme after the Tsunami disaster in December 2004 especially along the coast of Somalia. ii. The degreasing of the Quay Aprons at Port Elizabeth, Maputo, Dar-es-Salaam and Mongolism Sea Ports are also another major source polluting the Indian Ocean. PROBLEMS GENERATED AS A RESULT OF THE OCEANS POLLUTION i. Recent report

  6. Atlantic and indian oceans pollution in africa

    NASA Astrophysics Data System (ADS)

    Abubakar, Babagana

    Africa is the second largest and most populated continent after Asia. Geographically it is located between the Atlantic and Indian Oceans. Most of the Africa's most populated and industrialized cities are located along the coast of the continent facing the Atlantic and Indian Oceans, example of such cities include Casablanca, Dakar, Accra, Lagos, Luanda and Cape town all facing the Atlantic Ocean and cities like East London, Durban, Maputo, Dar-es-salaam and Mogadishu are all facing the Indian Ocean. As a result of the geographical locations of African Coastal Cities plus increase in their population, industries, sea port operations, petroleum exploration activities, trafficking of toxic wastes and improper waste management culture lead to the incessant increase in the pollution of the two oceans. NATURE OF POLLUTION OF THE ATLANTIC OCEAN i. The petroleum exploration activities going on along the coast of "Gulf of Guinea" region and Angola continuously causes oil spillages in the process of drilling, bunkering and discharging of petroleum products in the Atlantic Ocean. ii. The incessant degreasing of the Sea Ports "Quay Aprons" along the Coastal cities of Lagos, Luanda, Cape Town etc are continuously polluting the Atlantic Ocean with chemicals. iii. Local wastes generated from the houses located in the coastal cities are always finding their ways into the Atlantic Ocean. NATURE OF POLLUTION OF THE INDIAN OCEAN i. Unlike the Atlantic ocean where petroleum is the major pollutant, the Indian Ocean is polluted by Toxic / Radioactive waste suspected to have been coming from the developed nations as reported by the United Nations Environmental Programme after the Tsunami disaster in December 2004 especially along the coast of Somalia. ii. The degreasing of the Quay Aprons at Port Elizabeth, Maputo, Dar-es-Salaam and Mongolism Sea Ports are also another major source polluting the Indian Ocean. PROBLEMS GENERATED AS A RESULT OF THE OCEANS POLLUTION i. Recent report

  7. Biogeographical Patterns of Marine Benthic Invertebrates Along the Atlantic Coast of the Northeastern USA

    EPA Science Inventory

    Aim Examine the biogeography of marine benthic invertebrates of the Atlantic coast of the northeastern USA, compare the results to historical biogeographic studies, define physical-chemical factors affecting species distributions, and provide biogeographic information needed to ...

  8. 76 FR 39313 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-06

    ... butterfish is 495 mt (76 FR 8306, February 14, 2011). Section 648.22 requires NMFS to close the directed... Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the Directed... under the Atlantic Mackerel, Squid, and Butterfish Fishery Management Plan (FMP). The procedures...

  9. 75 FR 20550 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Specifications

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-20

    ... National Oceanic and Atmospheric Administration 50 CFR Part 648 RIN 0648-AY14 Fisheries of the Northeastern United States; Atlantic Herring Fishery; Specifications AGENCY: National Marine Fisheries Service (NMFS... comments. SUMMARY: NMFS proposes 2010-2012 specifications for the Atlantic herring (herring) fishery....

  10. 76 FR 68657 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Temporary Removal of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-07

    ... 38,146 mt, and 0 mt of the sub-ACL is set aside for research (75 FR 48874, August 12, 2010). Section... Northeastern United States; Atlantic Herring Fishery; Temporary Removal of Herring Trip Limit in Atlantic Herring Management Area 3 AGENCY: National Marine Fisheries Service (NMFS), National Oceanic...

  11. 76 FR 51272 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-18

    ... Loligo was set at 3,384 mt (76 FR 8306, February 14, 2011). Due to an under harvest of the Trimester 1... Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the 2011 Trimester 2 Directed Loligo Squid Fishery AGENCY: National Marine Fisheries Service (NMFS), National Oceanic...

  12. 77 FR 22678 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-17

    ... percent of the quota (8,888 mt) (77 FR 16472, March 21, 2012). The regulations also require the... Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the Trimester 1 Longfin Squid Fishery AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and...

  13. 77 FR 40527 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-10

    ... percent of the quota (8,888 mt) (77 FR 16472, March 21, 2012). Due to an underharvest of quota in... Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the 2012 Trimester 2 Directed Longfin Squid Fishery AGENCY: National Marine Fisheries Service (NMFS), National Oceanic...

  14. 75 FR 48874 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Specifications

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-12

    ... on April 20, 2010 (75 FR 20550), with public comment accepted through May 20, 2010. These final... National Oceanic and Atmospheric Administration 50 CFR Part 648 RIN 0648-AY14 Fisheries of the Northeastern United States; Atlantic Herring Fishery; Specifications AGENCY: National Marine Fisheries Service...

  15. 78 FR 62471 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Framework Adjustment 2 and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-22

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 648 RIN 0648-BD17 Fisheries of the Northeastern United States; Atlantic Herring Fishery; Framework Adjustment 2 and Specifications Correction In...

  16. 76 FR 11373 - Fisheries of the Northeastern United States; Atlantic Herring; Amendment 4

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-02

    ... United States; Atlantic Herring; Amendment 4 AGENCY: National Marine Fisheries Service (NMFS), National... amended as follows: PART 648--FISHERIES OF THE NORTHEASTERN UNITED STATES 0 1. The authority citation for... Herring FMP. With the implementation of Amendment 1 to the Herring FMP (72 FR 11252, March 12, 2007),...

  17. Fathers in hot water: rising sea temperatures and a Northeastern Atlantic pipefish baby boom.

    PubMed

    Kirby, Richard R; Johns, David G; Lindley, John A

    2006-12-22

    We report unprecedented numbers of juvenile snake pipefish, Entelurus aequoreus, in continuous plankton records of the Northeastern Atlantic since 2002. Increased sea surface temperatures (SSTs) in the Northern Hemisphere, linked to global warming, are a likely cause. Analysis of a long-term time-series of SST data in the Northeastern Atlantic shows a rise in winter, spring and summer sea temperatures (January-September), when the eggs of E. aqueoreus, which are brooded by the male, are developing and the larvae are growing in plankton. From what is known of the reproductive biology of closely related species, we suggest that the increased abundance of larval and juvenile E. aequoreus in the plankton as far west as the Mid-Atlantic Ridge may reflect the impact of temperature on abundance, through its effects on the operational sex ratio and potential reproductive rate, the onset of the breeding season and juvenile survival in this sex role reversed fish.

  18. Fathers in hot water: rising sea temperatures and a Northeastern Atlantic pipefish baby boom

    PubMed Central

    Kirby, Richard R; Johns, David G; Lindley, John A

    2006-01-01

    We report unprecedented numbers of juvenile snake pipefish, Entelurus aequoreus, in continuous plankton records of the Northeastern Atlantic since 2002. Increased sea surface temperatures (SSTs) in the Northern Hemisphere, linked to global warming, are a likely cause. Analysis of a long-term time-series of SST data in the Northeastern Atlantic shows a rise in winter, spring and summer sea temperatures (January–September), when the eggs of E. aqueoreus, which are brooded by the male, are developing and the larvae are growing in plankton. From what is known of the reproductive biology of closely related species, we suggest that the increased abundance of larval and juvenile E. aequoreus in the plankton as far west as the Mid-Atlantic Ridge may reflect the impact of temperature on abundance, through its effects on the operational sex ratio and potential reproductive rate, the onset of the breeding season and juvenile survival in this sex role reversed fish. PMID:17148298

  19. 76 FR 61059 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Sub-ACL (Annual Catch...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-03

    ...,362 mt and 0 mt of the sub-ACL is set aside for research (75 FR 48874, August 12, 2010). The... Northeastern United States; Atlantic Herring Fishery; Sub-ACL (Annual Catch Limit) Harvested for Management... 2,000 lb (907.2 kg) of Atlantic herring (herring) in or from Management Area 1B (Area 1B)...

  20. 78 FR 63406 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Sub-Annual Catch Limit...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-24

    ... (October 4, 2013, 78 FR 61828). The regulations at Sec. 648.201 require that when the Administrator... Northeastern United States; Atlantic Herring Fishery; Sub-Annual Catch Limit (ACL) Harvested for Management...) of Atlantic herring (herring) per trip or calendar day in or from Management Area 3 until January...

  1. 77 FR 10977 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Sub-Annual Catch Limit...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-24

    ... specifications (75 FR 48874, August 12, 2010). However, due to an over- harvest in Area 1B in 2010, the FY 2012... Northeastern United States; Atlantic Herring Fishery; Sub-Annual Catch Limit (ACL) Harvested for Management... than 2,000 lb (907.2 kg) of Atlantic herring in or from Management Area 1B per calendar day...

  2. 75 FR 69903 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Temporary Removal of 2,000...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-16

    ... herring specifications for 2010-2012 published on August 12, 2010 (75 FR 48874). The 2010 total TAC is 91... Northeastern United States; Atlantic Herring Fishery; Temporary Removal of 2,000-lb (907.2 kg) Herring Trip Limit in Atlantic Herring Management Area 1A AGENCY: National Marine Fisheries Service (NMFS),...

  3. 76 FR 61061 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Sub-ACL (Annual Catch...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-03

    ... is 38,146 mt and 0 mt of the sub-ACL is set aside for research (75 FR 48874, August 12, 2010). The... Northeastern United States; Atlantic Herring Fishery; Sub-ACL (Annual Catch Limit) Harvested for Management... 2,000 lb (907.2 kg) of Atlantic herring (herring) in or from Management Area 3 (Area 3) per...

  4. Atlantic forcing of persistent drought in West Africa.

    PubMed

    Shanahan, T M; Overpeck, J T; Anchukaitis, K J; Beck, J W; Cole, J E; Dettman, D L; Peck, J A; Scholz, C A; King, J W

    2009-04-17

    Although persistent drought in West Africa is well documented from the instrumental record and has been primarily attributed to changing Atlantic sea surface temperatures, little is known about the length, severity, and origin of drought before the 20th century. We combined geomorphic, isotopic, and geochemical evidence from the sediments of Lake Bosumtwi, Ghana, to reconstruct natural variability in the African monsoon over the past three millennia. We find that intervals of severe drought lasting for periods ranging from decades to centuries are characteristic of the monsoon and are linked to natural variations in Atlantic temperatures. Thus the severe drought of recent decades is not anomalous in the context of the past three millennia, indicating that the monsoon is capable of longer and more severe future droughts.

  5. 78 FR 11809 - Fisheries of the Northeastern United States; Atlantic Bluefish Fishery; 2013-2014 Atlantic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-20

    .... Christopher M. Moore, Executive Director, Mid-Atlantic Fishery Management Council, Suite 201, 800 N. State... overfishing. Authority: 16 U.S.C. 1801 et seq. Dated: February 12, 2013. Alan D. Risenhoover, Director,...

  6. 77 FR 8776 - Fisheries of the Northeastern United States; Atlantic Bluefish Fishery; 2012 Atlantic Bluefish...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-15

    .... Moore, Executive Director, Mid-Atlantic Fishery Management Council, Suite 201, 800 N. State Street... Monitoring Committee. Authority: 16 U.S.C. 1801 et seq. Dated: February 9, 2012. Alan D. Risenhoover,...

  7. Application of otolith mass and shape for discriminating scabbardfishes Aphanopus spp. in the north-eastern Atlantic Ocean.

    PubMed

    Tuset, V M; Parisi-Baradad, V; Lombarte, A

    2013-05-01

    The otolith was used to investigate the variability between Aphanopus carbo and Aphanopus intermedius inhabiting the north-eastern Atlantic Ocean. The results indicate a high degree of morphological affinity between species and areas; a noticeable metabolic change in the otolith shape was noted in the specimens of A. carbo, which may be related to migrations of individuals from shallow water (closer to the continental coast) to deeper water (archipelagos of Madeira and the Canary Islands). The results suggest a single population for both species in the north-eastern Atlantic Ocean, although not conclusively.

  8. Spigelia genuflexa (Loganiaceae), a new geocarpic species from the Atlantic forest of northeastern Bahia, Brazil

    PubMed Central

    Popovkin, Alex V.; Mathews, Katherine G.; Santos, José Carlos Mendes; Molina, M. Carmen; Struwe, Lena

    2011-01-01

    Abstract A new species of Spigelia L. (Loganiaceae), Spigelia genuflexa Popovkin & Struwe, sp. n., from the Atlantic forest of northeastern Bahia, Brazil, is described, being the first reported geocarpic species in the family. During fruit maturation, the basal infructescences bend down towards the ground, depositing the fruit on the surface (and burying it in soft kinds of ground cover, e.g., moss), whereas the upper ones do so slightly but noticeably. The species is a short-lived annual apparently restricted to sandy-soil habitat of the Atlantic forest of northeastern Bahia, with variable and heterogeneous microenvironment and is known from only two restricted localities. A short review of amphi- and geocarpic species is provided. A discussion of comparative morphology within Spigelia with regards to dwarfism, indumentum, and annual habit is included. A phylogenetic parsimony and Bayesian analysis of ITS sequences from 15 Spigelia species plus 17 outgroups in Loganiaceae confirms its independent taxonomic status: on the basis of sequence similarity and phylogenetic topology it is phylogenetically distinct from all Spigelia species sequenced so far. PMID:22287919

  9. 75 FR 27221 - Fisheries of the Northeastern United States; Atlantic Bluefish Fishery; 2010 Atlantic Bluefish...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-14

    ... proposed specifications (75 FR 10450, March 8, 2010), and will not be repeated here. Final Specifications... RSA Program was published on January 2, 2009 (74 FR 72). Two research projects that would utilize... harvest limit, and recreational possession limits for Atlantic bluefish off the east coast of the U.S....

  10. 75 FR 10450 - Fisheries of the Northeastern United States; Atlantic Bluefish Fisheries; 2010 Atlantic Bluefish...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-08

    ...). Alternative 3, the no action alternative, is considered to be synonymous with status quo management measures... a given phase in the rebuilding period, or the status quo F, whichever is less. According to... alternatives (including a no action/status quo alternative) for 2010 Atlantic bluefish fishery. All...

  11. 77 FR 61299 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Sub-ACL (Annual Catch...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-09

    ... research in the 2010-2012 specifications (75 FR 48874, August 12, 2010). Section 648.201 requires the... Northeastern United States; Atlantic Herring Fishery; Sub-ACL (Annual Catch Limit) Harvested for Management... Administration (NOAA), Commerce. ACTION: Temporary rule; closure. SUMMARY: NMFS is closing the directed...

  12. 78 FR 21071 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Sub-ACL (Annual Catch...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-09

    ...-ACL is set aside for research (75 FR 48874, August 12, 2010). The regulations at Sec. 648.201 require... Northeastern United States; Atlantic Herring Fishery; Sub-ACL (Annual Catch Limit) Harvested for Management... Administration (NOAA), Commerce. ACTION: Temporary rule; closure. SUMMARY: NMFS is closing the directed...

  13. 76 FR 66654 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Sub-ACL (Annual Catch...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-27

    ... 1A is 26,546 mt, and 0 mt of the sub-ACL is set aside for research (75 FR 48874, August 12, 2010... Northeastern United States; Atlantic Herring Fishery; Sub-ACL (Annual Catch Limit) Harvested for Management... Administration (NOAA), Commerce. ACTION: Temporary rule; closure. SUMMARY: NMFS is closing the directed...

  14. 77 FR 10668 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Sub-ACL (Annual Catch...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-23

    ... 22,146 mt, and 0 mt of the sub-ACL is set aside for research (75 FR 48874, August 12, 2010). Section... Northeastern United States; Atlantic Herring Fishery; Sub-ACL (Annual Catch Limit) Harvested for Management... Administration (NOAA), Commerce. ACTION: Temporary rule; closure. SUMMARY: NMFS is closing the directed...

  15. 78 FR 62331 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Sub-Annual Catch Limit...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-17

    ... herring catch will reach 92 percent of the sub-ACL allocated in any of the four management areas... Northeastern United States; Atlantic Herring Fishery; Sub-Annual Catch Limit (ACL) Harvested for Management... fishery in management area 1A, because it projects that 92 percent of the catch limit for that area...

  16. Reconstructing precipitation changes in northeastern Africa during the Quaternary by clay mineralogical and geochemical investigations of Nile deep-sea fan sediments

    NASA Astrophysics Data System (ADS)

    Zhao, Yulong; Colin, Christophe; Liu, Zhifei; Paterne, Martine; Siani, Giuseppe; Xie, Xin

    2012-12-01

    Clay mineralogy combined with high-resolution element geochemistry of core MD90-9064, located in the distal part of the Nile deep-sea fan (Levantine Basin), have been investigated to reconstruct rainfall changes in northeastern Africa during the Quaternary and to determine possible climatic controls. Clay minerals of core MD90-964 are derived mainly from three sedimentary sources (the Sahara, Nile River and Egyptian wadis) and are characterized by contrasted mineralogical composition. Variations in illite content and logarithm ratios of Si/Al and K/Al permit the tracking of eolian input from Sahara to the Mediterranean Sea. It is suggested that precipitation changes in the Sahara are mainly dominated by glacial-interglacial cycles. Such variations are owing to a shift of climatic conditions in the North Atlantic from a NAO-positive-like condition in glacial times to a NAO-negative-like condition in interglacial times. Fe content in the Levantine sediments is mostly derived from Fe-bearing heavy minerals brought by the Nile River. Therefore, variations of Fe/Al ratios can be used to establish precipitation changes in the Nile River basin. Long-term variation in precipitation in the Nile River basin is governed by precessional and eccentricity signals, implying that the African monsoon is the most significant controlling factor for precipitation changes in this region. Precipitation changes in the northeastern coasts of Africa are reconstructed using kaolinite contents provided by the Egyptian wadis. It is reported that precipitation in coastal northeastern Africa is mainly of the Mediterranean-climate type. Long-term variations in rainfall in this region are also affected by the NAO-like climatic variability and thus dominated by the glacial-interglacial cycles.

  17. Modeling the impact of changes in Atlantic sea surface temperature on the climate of West Africa

    NASA Astrophysics Data System (ADS)

    Adeniyi, Mojisola O.

    2016-08-01

    This study assesses the impacts of warming/cooling of the Atlantic sea surface temperature (SST) on the climate of West Africa using Version 4.4 of Regional Climate Model (RegCM4.4) of International Center for Theoretical Physics, Trieste, Italy. The 1-2 K cooling and warming of the Atlantic SST both result in tripole temperature and precipitation change structure, having a northwest-southeast orientation over West Africa. Findings reveal that the responses of precipitation and temperature to the Atlantic SST cooling are opposite to those for the Atlantic SST warming and these responses intensify with increased warming/cooling of the Atlantic SST. The structure of the change in climate is attributed to the response of atmospheric/soil moisture gradient and orientation of orography in West Africa.

  18. Can seamounts provide a good habitat for polychaete annelids? Example of the northeastern Atlantic seamounts

    NASA Astrophysics Data System (ADS)

    Surugiu, Victor; Dauvin, Jean-Claude; Gillet, Patrick; Ruellet, Thierry

    2008-11-01

    Two seamount groups in the northeastern Atlantic were investigated during the 1980s and 1990s: the first was located along the Iberian and African coasts (Galicia, to the north of Portugal; and the Ampere, Gorringe, Josephine and Seine banks near the Madeira-Canary Islands) and the second was located offshore of the southern part of the Azores Islands, included the Atlantis, Hyeres, Irving, Meteor and Plato banks. Among the invertebrates, Annelida, specifically Polychaeta, were studied as surrogates for the biogeographical relationship between coastal and mid-oceanic seamounts in the northeastern Atlantic and the fauna in these areas. The dominant families were Onuphidae (27.46%), Syllidae (18.23%), Eunicidae (15.65%), Amphinomidae (11.45%) and Nereididae (5.61%), representing 78.4% of the total fauna. Data analyses clearly distinguished two seamount groups, one for coastal seamounts and the other offshore. Although the species distinguished and the family composition at the sampled sites were different (i.e., most diversified at the Josephine site and most impoverished at the Irving site), no coastal/offshore faunal impoverishment gradient could be identified. Thus, it seems that seamount environments do not favour any relationship between planktotrophic development and the direct development of polychaetes. Though the number of apparent endemic species was low (<7%), it remained in keeping with other invertebrate groups. Still, while seamounts may well encourage oceanic biodiversity in some zoological groups, this was clearly not the case for the polychaetes. We offer two explanations for this paradox: pelagic productivity and local environmental conditions.

  19. A new species of porcupine, genus Coendou (Rodentia: Erethizontidae) from the Atlantic forest of northeastern Brazil.

    PubMed

    Pontes, Antonio Rossano Mendes; Gadelha, José Ramon; Melo, Éverton R A; de Sá, Fabrício Bezerra; Loss, Ana Carolina; Caldara Junior, Vilacio; Costa, Leonora Pires; Leite, Yuri L R

    2013-01-01

    We report the discovery of a new species of Coendou (Rodentia, Erethizontidae), here designated Coendou speratus sp. nov. This small porcupine, locally known as coandumirim, is found in the Pernambuco Endemism Centre in the Atlantic coast of northeastern Brazil north of the São Francisco river, one of the most important known biodiversity hotspots. The geographic range of C. speratus overlaps with that of the larger, widespread C. prehensilis, but not with that of C. insidiosus from the southeastern Atlantic forest, nor with that of C. nycthemera, an eastern Amazonian species. Coendou speratus is a small-bodied, long-tailed species that appears to be completely spiny because it lacks long dorsal fur. The dorsal quills have conspicuously brownish red tips that contrast with the blackish dorsal background color. The new species is overall similar to C. nycthemera, but the dorsal body quills are typically tricolored in the former and bicolored in the latter. The new species is externally very distinct from C. insidiosus, especially because the latter has bicolored dorsal quills that are almost completely hidden beneath longer and homogeneous pale or dark hairs. PMID:26042302

  20. Iodine isotopes species fingerprinting environmental conditions in surface water along the northeastern Atlantic Ocean

    PubMed Central

    He, Peng; Hou, Xiaolin; Aldahan, Ala; Possnert, Göran; Yi, Peng

    2013-01-01

    Concentrations and species of iodine isotopes (127I and 129I) provide vital information about iodine geochemistry, environmental conditions and water masses exchange in oceans. Despite extensive investigations of anthropogenic 129I in the Arctic Ocean and the Nordic Seas, concentrations of the isotope in the Atlantic Ocean are, however, still unknown. We here present first data on 129I and 127I, and their species (iodide and iodate) in surface water transect along the northeastern Atlantic between 30° and 50°N. The results show iodate as the predominant species in the analyzed marine waters for both 127I and 129I. Despite the rather constant ratios of 127I−/127IO3−, the 129I−/129IO3− values reveal variations that apparently response to sources, environmental conditions and residence time. These findings provide a new tracer approach that will strongly enhance the application of anthropogenic 129I in ocean environments and impact on climate at the ocean boundary layer. PMID:24284916

  1. A new species of porcupine, genus Coendou (Rodentia: Erethizontidae) from the Atlantic forest of northeastern Brazil.

    PubMed

    Pontes, Antonio Rossano Mendes; Gadelha, José Ramon; Melo, Éverton R A; de Sá, Fabrício Bezerra; Loss, Ana Carolina; Caldara Junior, Vilacio; Costa, Leonora Pires; Leite, Yuri L R

    2013-01-01

    We report the discovery of a new species of Coendou (Rodentia, Erethizontidae), here designated Coendou speratus sp. nov. This small porcupine, locally known as coandumirim, is found in the Pernambuco Endemism Centre in the Atlantic coast of northeastern Brazil north of the São Francisco river, one of the most important known biodiversity hotspots. The geographic range of C. speratus overlaps with that of the larger, widespread C. prehensilis, but not with that of C. insidiosus from the southeastern Atlantic forest, nor with that of C. nycthemera, an eastern Amazonian species. Coendou speratus is a small-bodied, long-tailed species that appears to be completely spiny because it lacks long dorsal fur. The dorsal quills have conspicuously brownish red tips that contrast with the blackish dorsal background color. The new species is overall similar to C. nycthemera, but the dorsal body quills are typically tricolored in the former and bicolored in the latter. The new species is externally very distinct from C. insidiosus, especially because the latter has bicolored dorsal quills that are almost completely hidden beneath longer and homogeneous pale or dark hairs.

  2. Late Holocene intermediate water variability in the northeastern Atlantic as recorded by deep-sea corals

    NASA Astrophysics Data System (ADS)

    Copard, K.; Colin, C.; Henderson, G. M.; Scholten, J.; Douville, E.; Sicre, M.-A.; Frank, N.

    2012-01-01

    The Nd isotopic composition of the aragonite skeleton of fossil deep-sea corals ( Lophelia pertusa, Madrepora oculata and Desmophyllum dianthus) located in the northeastern Atlantic at water depths between 635 and 1300 m was investigated to reconstruct changes in the Atlantic mid-depth gyre circulation during the past millennium. The coral ɛNd values varied systematically from - 11.8 to - 14.4 during the past 1500 years, reflecting variations in seawater ɛNd and thus water mass provenance. Low ɛNd values (ɛNd = - 14) occurred during the warm Medieval Climatic Anomaly (MCA) (between 1000 AD and 1250 AD) and during the most recent period (1950 AD to 2000 AD), interrupted by a period of significantly higher ɛNd values (~-12.5) during the Little Ice Age (LIA) (between 1350 AD and 1850 AD). One long-lived branching coral even recorded an abrupt systematic rise from low to high ɛNd values around 1250 AD over the course of its 10-year growth period. These variations are interpreted to result from variable contributions of the subpolar and subtropical Atlantic intermediate water masses, which today are characterized by ɛNd values of - 15 and ~-11, respectively. The low ɛNd values observed during the warm MCA and during recent times imply a strong eastward extension of the mid-depth subpolar gyre (SPG) induced by a dominant positive phase of the North Atlantic oscillation (NAO). During the LIA, water from the subtropical gyre (STG) and potentially from the Mediterranean Sea Water (MSW) propagated further northward, as indicated by the higher coral ɛNd values. This pattern suggests a negative mean state of the NAO during the LIA, with weaker and more southerly located Westerlies and a westward contraction of the SPG. Variations in the contributions of the two gyres imply changes in the heat and salt budgets at intermediate depths during the past millennia that may have contributed to changes in the properties of North Atlantic inflow into the Nordic Seas and thus

  3. The North Atlantic Oscillation: Impact on Snowfall Conditions in the Northeastern U.S

    NASA Astrophysics Data System (ADS)

    Budikova, D.; Widen, H.; Coleman, J. S.

    2013-12-01

    The North Atlantic Oscillation (NAO) is one of the main components of atmospheric circulation variability within the middle and high latitudes of the Northern Hemisphere, particularly impacting winter weather patterns in northeastern United States. Previous research has indicated greater snowfall totals and higher frequency of snowfall days in the Northeast during a NAO negative phase due to repeated polar outbreaks; yet, the NAO positive phase has also been associated with extreme snowfall events in this region. This study examines the relationship between the NAO and winter (December - February) snowfall totals in northeastern U.S. between 1961 and 2010. Two case studies of recent winter events with differing NAO phases were evaluated to provide insight on how both NAO phases can produce significant snowfall in portions of the Northeast. The analysis revealed an inverse relationship between the NAO phase and seasonal snowfall, with positive (negative) NAO index years associated with lower (higher) average snowfall and snowfall days. Significantly greater snowfall during the NAO negative phase was mainly located along the East Coast as well as the interior southern half of the study region. A composite analysis of various tropospheric variables (e.g., 500-hPa heights) showed NAO negative years produced greater snowfall due to more extreme weather conditions affecting the Northeast, such as below normal sea level pressure, a deepened mid-tropospheric trough and weaker upper-level westerlies that permitted more frequent polar outbreaks. The intrusion of cold polar air into the interior U.S. generates more extreme temperature gradients and produces snowfall farther south than the NAO positive phase. In addition, the eastward displacement of the storms in the NAO negative phase along with the available moisture from the Atlantic Ocean creates more snowfall along the East Coast. These results correspond to the spatial distribution of snowfall that occurred during the

  4. Response of the Water Cycle of West Africa and Atlantic to Radiative Forcing by Saharan Dust

    NASA Technical Reports Server (NTRS)

    Lau, K. M.; Kim, Kyu-Myong; Sud, Yogesh C.; Walker, Gregory L.

    2010-01-01

    The responses of the atmospheric water cycle and climate of West Africa and the Atlantic to radiative forcing of Saharan dust are studied using the NASA finite volume general circulation model (fvGCM), coupled to a mixed layer ocean. We find evidence in support of the "elevated heat pump" (EHP) mechanism that underlines the responses of the atmospheric water cycle to dust forcing as follow. During the boreal summer, as a result of large-scale atmospheric feed back triggered by absorbing dust aerosols, rainfall and cloudiness are enhanced over the West Africa/Easter Atlantic ITCZ, and suppressed over the West Atlantic and Caribbean. region. Shortwave radiation absorption by dust warms the atmosphere and cools the surface, while long wave has the opposite response. The elevated dust layer warms the air over Nest Africa and the eastern Atlantic. The condensation heating associated with the induced deep convection drives and maintains an anomalous large-scale east-west overturning circulation with rising motion over West Africa/eastern Atlantic, and sinking motion over the Caribbean region. The response also includes a strengthening of the West African monsoon, manifested in northward shift of the West Africa precipitation over land, increased low-level westerlies flow over West Africa at the southern edge of the dust layer, and a near surface energy fluxes, resulting in cooling of the Nest African land and the eastern Atlantic, and a warming in the West Atlantic and Caribbean. The EHP effect is most effective for moderate to highly absorbing dusts, and becomes minimized for reflecting dust with single scattering albedo at 0.95 or higher.

  5. Hydrography and through-flow in the north-eastern North Atlantic Ocean: the NANSEN project

    NASA Astrophysics Data System (ADS)

    van Aken, H. M.; Becker, G.

    The circulation and hydrography of the north-eastern North Atlantic has been studied with an emphasis on the upper layers and the deep water types which take part in the thermohaline overturning of the Oceanic Conveyor Belt. Over 900 hydrographic stations were used for this study, mainly from the 1987-1991 period. The hydrographic properties of Subpolar Mode Water in the upper layer, which is transported towards the Norwegian Sea, showed large regional variation. The deep water mass was dominated by the cold inflow of deep water from the Norwegian Sea and by a cyclonic recirculation of Lower Deep Water with a high Antarctic Bottom Water content. At intermediate levels the dominating water type was Labrador Sea Water with only minor influence of Mediterranean Sea Water. In the permanent pycnocline traces of Antarctic Intermediate Water were found. Geostrophic transports have been estimated, and these agreed in order of magnitude with the local heat budget, with current measurements, with data from surface drifters, and with the observed water mass modification. A total of 23 Sv of surface water entered the region, of which 20 Sv originated from the North Atlantic Current, while 3 Sv entered via an eastern boundary current. Of this total, 13 Sv of surface water left the area across the Reykjanes Ridge, and 7 Sv entered the Norwegian Sea, while 3 Sv was entrained by the cold overflow across the Iceland-Scotland Ridge. Approximately 1.4 Sv of Norwegian Sea Deep Water was involved in the overflow into the Iceland Basin, which, with about 1.1 Sv of entrained water and 1.1 Sv recirculating Lower Deep Water, formed a deep northern boundary current in the Iceland Basin. At intermediate depths, where Labrador Sea Water formed the dominant water type, about 2 Sv of entrained surface water contributed to a saline water mass which was transported westwards along the south Icelandic slope.

  6. Occurrence and characteristics of mesoscale eddies in the tropical northeastern Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Schütte, Florian; Brandt, Peter; Karstensen, Johannes

    2016-05-01

    Coherent mesoscale features (referred to here as eddies) in the tropical northeastern Atlantic Ocean (between 12-22° N and 15-26° W) are examined and characterized. The eddies' surface signatures are investigated using 19 years of satellite-derived sea level anomaly (SLA) data. Two automated detection methods are applied, the geometrical method based on closed streamlines around eddy cores, and the Okubo-Weiß method based on the relation between vorticity and strain. Both methods give similar results. Mean eddy surface signatures of SLA, sea surface temperature (SST) and sea surface salinity (SSS) anomalies are obtained from composites of all snapshots around identified eddy cores. Anticyclones/cyclones are identified by an elevation/depression of SLA and enhanced/reduced SST and SSS in their cores. However, about 20 % of all anticyclonically rotating eddies show reduced SST and reduced SSS instead. These kind of eddies are classified as anticyclonic mode-water eddies (ACMEs). About 146 ± 4 eddies per year with a minimum lifetime of 7 days are identified (52 % cyclones, 39 % anticyclones, 9 % ACMEs) with rather similar mean radii of about 56 ± 12 km. Based on concurrent in situ temperature and salinity profiles (from Argo float, shipboard, and mooring data) taken inside of eddies, distinct mean vertical structures of the three eddy types are determined. Most eddies are generated preferentially in boreal summer and along the West African coast at three distinct coastal headland regions and carry South Atlantic Central Water supplied by the northward flow within the Mauretanian coastal current system. Westward eddy propagation (on average about 3.00 ± 2.15 km d-1) is confined to distinct zonal corridors with a small meridional deflection dependent on the eddy type (anticyclones - equatorward, cyclones - poleward, ACMEs - no deflection). Heat and salt fluxes out of the coastal region and across the Cape Verde Frontal Zone, which separates the shadow zone from

  7. Ectoparasites of bats (Mammalia: Chiroptera) in Atlantic forest fragments in north-eastern Brazil.

    PubMed

    Bezerra, Rayanna Hellem Santos; de Vasconcelos, Pedro Fonseca; Bocchiglieri, Adriana

    2016-10-01

    In Brazil, most studies involving parasites of bats (bat flies) treat the mid-west, south-east, and south of the country. This work aimed to characterize the ectoparasites community associated with bats in the Atlantic forest in the state of Sergipe, north-eastern Brazil. Sampling was conducted between January and June 2013 in the Serra de Itabaiana National Park (PNSI) and between November 2013 and June 2015 in the Wildlife Refuge Mata do Junco (RVSMJ). Parasitological indexes were determined, and the influence of host sex and the seasonality in prevalence rates and mean intensity for the most abundant parasites was evaluated. Some 129 parasites were collected in PNSI and 296 in RVSMJ, and 100 and 70.6 %, respectively, belong to the family Streblidae. The differences in parasitological rates in Sergipe in relation to other studies may be associated with the environmental characteristics and the composition of the host community. The influence of sex and the seasonal prevalence of Speiseria ambigua and Trichobius joblingi, associated with Carollia perspicillata, may be associated with a lower rate of female captures and low sampling in the dry season. This is a pioneer study in Sergipe that reveals the occurrence of 16 species of streblids and representatives of Acari and Basilia spp., highlighting the need for more studies to increase the wealth and understanding of host-parasite associations in the state.

  8. Chimaera opalescens n. sp., a new chimaeroid (Chondrichthyes: Holocephali) from the north-eastern Atlantic Ocean.

    PubMed

    Luchetti, E A; Iglésias, S P; Sellos, D Y

    2011-08-01

    A new species of chimaeroid, Chimaera opalescens n. sp., was described from 31 type specimens caught in the north-eastern Atlantic Ocean at 950-1400 m depth. This species differed from all its congeners by the combination of the following characters: body uniformly pale brown to bronze, iridescent on fresh specimens; unpaired fins brown to purple, uniformly coloured or with pale or whitish edges; iris black; claspers tripartite and divided for a third of their length, not extending beyond the pelvic fins in adults; dorsal spine equal to or shorter than first dorsal fin; ventral caudal lobe equal to or deeper than dorsal caudal lobe. Comparison of DNA sequences of the CO1 gene with those of related species supported C. opalescens n. sp. as a distinct species. Specimens of C. opalescens n. sp. were previously misidentified as Chimaera monstrosa, a species sharing a similar geographical distribution. Chimaera opalescens n. sp. lives in deeper water and is a larger-bodied species than C. monstrosa. The two species were newly exploited by deep-sea fisheries and confused under a single landing name.

  9. Multiple recurrent evolution of trophic types in northeastern Atlantic and Mediterranean seabreams (Sparidae, Percoidei).

    PubMed

    Hanel, R; Sturmbauer, C

    2000-03-01

    Seabreams are among the most valuable fish, not only for small-scale and semiindustrial fisheries but also for aquaculture throughout the Mediterranean. Nevertheless, their phylogenetic relationships are not at all clear. The current taxonomy is based solely on trophic morphology and rests on the assumption that each trophic type evolved only once from a less specialized ancestral condition. We analyzed a 486-bp segment of the mitochondrial 16S rDNA of all 24 seabream species described for the northeastern Atlantic and the Mediterranean to elucidate their generic and subfamily-level relationships. Three major mitochondrial lineages, each comprising species of different feeding strategy and dentition, were found that do not agree with the present taxonomic assignments. Most of the investigated genera were resolved paraphyletically, indicating that the structure and arrangement of oral teeth must have repeatedly evolved from a less specialized ancestral condition. Further, the genus Sparus was resolved as distantly related to the genus Pagrus, in that it was assigned to a different major mitochondrial lineage. Oblada melanura was consistently placed within the Diplodus radiation as sister group to Diplodus puntazzo. Our phylogenetic hypothesis thus suggests multiple independent origins of similar trophic specializations within the Sparidae and indicates that the currently recognized three or four subfamilies need to be redefined. PMID:10754071

  10. The morphology of saccular otoliths as a tool to identify different mugilid species from the Northeastern Atlantic and Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Callicó Fortunato, Roberta; Benedito Durà, Vicent; Volpedo, Alejandra

    2014-06-01

    In the Northeastern Atlantic and Mediterranean Sea there are 8 species of the Mugilidae family: Mugil cephalus, Liza aurata, Liza ramada, Oedalechilus labeo, Chelon labrosus, Liza saliens, Liza carinata and Liza haematocheila. The identification of mugilids is very important for local fisheries management and regulations, but it is difficult using gross morphological characters. This work aims to contribute to the identification of mullets present in the Northeastern Atlantic Ocean and Mediterranean Sea using saccular otolith features of each species. Specimens of C. labrosus, L. aurata, L. ramada, L. saliens and M. cephalus were obtained from Delta del Ebro (40°38'N-0°44'E) in artisanal catches. For L. carinata and O. labeo photographs extracted from AFORO online database were used. L. haematocheila was not studied for lack of otolith samples. A general pattern of the saccular otoliths for this family was identified: the shape of the otoliths are rectangular to oblong with irregular margins; they present a heterosulcoid, ostial sulcus acusticus, with an open funnel-like ostium to the anterior margin and a closed, tubular cauda, ending towards the posterior ventral corner, always larger than the ostium. In the present study, the mugilid species could be recognized using their saccular otolith morphology. Here we give the first key to identify Northeastern Atlantic and Mediterranean mullets. The distinctive features between the species were the position and centrality of the sulcus, the curvature of the cauda, the presence of areal depositions and plateaus, and the type of anterior and posterior regions. These features could be used not only to reinforce the identification keys through morphological and meristic characters of the species, but also to identify the species consumed by piscivores, being the otoliths the only identifiable remains of the individuals.

  11. Relevance of rangeland degradation in semiarid northeastern South Africa to the nonequilibrium theory.

    PubMed

    Wessels, Konrad J; Prince, A Stephen D; Carroll, Mark; Malherbe, Johan

    2007-04-01

    According to the nonequilibrium theory, livestock grazing has a limited effect on long-term vegetation productivity of semiarid rangelands, which is largely determined by rainfall. The communal lands in northeastern South Africa contain extensive degraded areas which have been mapped by the National Land Cover (NLC) program. Much evidence suggests that long-term heavy grazing is the cause of this degradation. In order to test for the prevalence of nonequilibrium dynamics, we determined the relative effects of rainfall- and grazing-induced degradation on vegetation productivity. The vegetation production in the NLC degraded areas was estimated using growth-season sums of the Normalized Difference Vegetation Index (sigmaNDVI), calculated using data from both the Advanced Very High Resolution Radiometer (AVHRR) (1985-2003) and Moderate-resolution Imaging Spectroradiometer (MODIS) (2000-2005). On average, rainfall and degradation accounted for 38% and 20% of the AVHRR sigmaNDVI variance and 50% and 33% of the MODIS sigmaNDVI variance, respectively. Thus, degradation had a significant influence on long-term vegetation productivity, and therefore the rangelands did not behave according to the nonequilibrium model, in which grazing is predicted to have a negligible long-term impact.

  12. 78 FR 3346 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-16

    ... rule for 2013 MSB specifications and management measures was published on November 19, 2012 (77 FR... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Specifications and Management Measures... measures for Atlantic mackerel, and 2013 specifications for butterfish. Specifications for longfin...

  13. 77 FR 69426 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-19

    ... available from: Dr. Christopher M. Moore, Executive Director, Mid-Atlantic Fishery Management Council, Suite... Part 648 Fisheries, Fishing, Recordkeeping and reporting requirements. Dated: November 14, 2012. Alan...

  14. Late Holocene climate change in the North Atlantic and equatorial Africa: Millennial-scale ITCZ migration

    NASA Astrophysics Data System (ADS)

    Russell, James M.; Johnson, Thomas C.

    2005-09-01

    Climate proxy data and numerical models suggest that latitudinal displacements of the Intertropical Convergence Zone (ITCZ) occur during millennial-scale cold events in the North Atlantic region, but the potential effects of these ITCZ movements on the climate of equatorial regions are unclear. Here we present a 5400-year geochemical record of rainfall and drought from Lake Edward in equatorial Africa. We observe a non-linear correlation in which drought in equatorial Africa occurs during both cold and warm extremes in the North Atlantic's 1500-year quasi-cycle. We propose that this relationship occurs due to northward/southward displacement of the ITCZ from its equatorial mean position during warm/cold events. Our results show that millennial-scale high-latitude climate events are linked to changes in equatorial terrestrial climate even during the late Holocene and suggest important constraints on the mechanisms linking tropical and extratropical climate variability.

  15. 77 FR 67305 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-09

    ... specifications (77 FR 16472; March 21, 2012). The total allowable level of foreign fishing (TALFF) for butterfish... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Specifications and Management Measures... butterfish fishery, which is managed as part of the Atlantic Mackerel, Squid, and Butterfish...

  16. 76 FR 74724 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-01

    ... November 7, 2011 (76 FR 68642). Details regarding the measures in Amendment 11 are in the final rule and... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Amendment 11 AGENCY: National Marine... implementing Amendment 11 to the Atlantic Mackerel, Squid, and Butterfish (MSB) Fishery Management Plan...

  17. 75 FR 32745 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-09

    ... meeting dates in a separate Federal Register notice published on May 27, 2010 (75 FR 29725). If the...; Atlantic Mackerel, Squid, and Butterfish Fisheries; Scoping Process AGENCY: National Marine Fisheries...) for Atlantic Mackerel, Squid, and Butterfish (MSB) and to prepare an EIS to analyze the impacts of...

  18. 77 FR 23635 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-20

    ..., 2011 (77 FR 16472). This action established catch levels for the 2012 fishing year for mackerel and... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Specifications and Management Measures... regulatory text in the final rule for 2012 Specifications for the Atlantic Mackerel, Squid, and...

  19. 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...

  20. 75 FR 36559 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery; Framework Adjustment 21

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-28

    ... delayed greatly beyond June 15, 2010, sea turtle conservation benefits during this short window of time... sea turtles as required by the March 14, 2008, Atlantic Sea Scallop Biological Opinion (Biological...-Atlantic during times when sea turtle distribution is expected to overlap with scallop fishing...

  1. 78 FR 46897 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Framework Adjustment 2 and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-02

    ... standards for several industries in a final rule effective July 22, 2013 (78 FR 37398, June 20, 2013). The... United States; Atlantic Herring Fishery; Framework Adjustment 2 and Specifications AGENCY: National... to the Atlantic herring Fishery Management Plan and the 2013-2015 fishery specifications for...

  2. 75 FR 56016 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Total Allowable Catch...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-15

    ... to Area 1B (75 FR 48874, August 12, 2010) is 4,362 mt; 0 mt of the TAC is set aside for research... United States; Atlantic Herring Fishery; Total Allowable Catch Harvested for Management Area 1B AGENCY...) of Atlantic herring in or from Management Area 1B (Area 1B) per trip or calendar day until January...

  3. 75 FR 69014 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Total Allowable Catch...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-10

    ... August 12, 2010 (75 FR 48874). The 2010 total TAC is 91,200 mt, allocated to the herring management areas... United States; Atlantic Herring Fishery; Total Allowable Catch Harvested for Management Area 1A AGENCY.... ACTION: Temporary rule; notification of trip limit reduction in Area 1A of the Atlantic Herring...

  4. 75 FR 22073 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery; Framework Adjustment 21

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-27

    ... United States; Atlantic Sea Scallop Fishery; Framework Adjustment 21 AGENCY: National Marine Fisheries...; request for comments. SUMMARY: NMFS proposes regulations to implement Framework Adjustment 21 (Framework 21) to the Atlantic Sea Scallop Fishery Management Plan (FMP), which was developed by the New...

  5. 75 FR 49420 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-13

    ... establish a target TAC greater than that recommended by the Council, the initial final rule (75 FR 27219... on June 22, 2010 (75 FR 35435), requesting public comment on the revised recommended catch level... (TAC) and corresponding fleet days-at-sea (DAS) allocation for the Atlantic deep- sea red crab...

  6. Decadal changes in the mid-depth water mass dynamic of the Northeastern Atlantic margin (Bay of Biscay)

    NASA Astrophysics Data System (ADS)

    Montero-Serrano, Jean-Carlos; Frank, Norbert; Tisnérat-Laborde, Nadine; Colin, Christophe; Wu, Chung-Che; Lin, Ke; Shen, Chuan-Chou; Copard, Kevin; Orejas, Covadonga; Gori, Andrea; De Mol, Lies; Van Rooij, David; Reverdin, Gilles; Douville, Eric

    2013-02-01

    The lithium/magnesium (Li/Mg) molar ratios, radiocarbon measurements (Δ14C) and Nd-isotopic composition (εNd) of the aragonite skeleton of a branching cold-water coral (CWC) species Madrepora oculata collected alive in the Bay of Biscay at ∼691 m water depth were investigated to reconstruct a robust record of the mid-depth water mass dynamics between 1950 and 1990 AD. Temperature estimates based on the skeletons Li/Mg molar ratios reveal small decadal changes of about 1 °C at thermocline depth synchronous to and of similar amplitude as surface temperature anomalies. Δ14C measurements shows quasi-decadal oscillations of 15‰ around pre-bomb Δ14C average value of -59±6‰ and post-bomb Δ14C of -12±6‰, which most likely reflect decadal changes of water mass exchange across the thermocline. The coral εNd values remain in narrow ranges of -11.9 to -10.2, similar to the isotopic composition of East North Atlantic Central Water, but show highest values in the late 1950s, and early 1960s, 1970s, and 1980s. The punctuated changes of the coral Nd-isotopic composition may thus reflect periods of particular enhanced advection of temperate intermediate water (mid-depth Subpolar Gyre/Mediterranean Sea Water). Altogether, our robust multi-proxy record provides new evidence that Northern Hemisphere atmospheric variability (such as, North Atlantic Oscillation and East Atlantic pattern) drives changes not only in the thermocline but also in the mid-depth water-mass advection patterns in the Northeastern Atlantic margin. However, the interannual variability of our record remains to be tested.

  7. Wood Litter Consumption by three Species of Nasutitermes Termites in an Area of the Atlantic Coastal Forest in Northeastern Brazil

    PubMed Central

    Vasconcellos, Alexandre; Moura, Flávia Maria da Silva

    2010-01-01

    Termites constitute a considerable fraction of the animal biomass in tropical forest, but little quantitative data are available that indicates their importance in the processes of wood decomposition. This study evaluated the participation of Nasutitermes corniger (Motschulsky) (Isoptera: Termitidae), N. ephratae (Holmgren), and N. macrocephalus (Silvestri) in the consumption of the wood litter in a remnant area of Atlantic Coastal Forest in northeastern Brazil. The populations of this species were quantified in nests and in decomposing tree trunks, while the rate of wood consumption was determined in the laboratory using wood test-blocks of Clitoria fairchildiana Howard (Fabales: Fabaceae), Cecropia sp. (Urticales: Cecropiaceae), and Protium heptaphyllum (Aublet) Marchand (Sapindales: Burseraceae). The abundance of the three species of termites varied from 40.8 to 462.2 individuals/m2. The average dry wood consumption for the three species was 9.4 mg/g of termites (fresh weight)/day, with N. macrocephalus demonstrating the greatest consumption (12.1 mg/g of termite (fresh weight)/day). Wood consumption by the three species of Nasutitermes was estimated to be 66.9 kg of dry wood /ha/year, corresponding to approximately 2.9% of the annual production of wood-litter in the study area. This consumption, together with that of the other 18 exclusively wood-feeders termite species known to occur in the area, indicates the important participation of termites in removing wood-litter within the Atlantic Coastal Forest domain. PMID:20673190

  8. Description of two new genera and two new species of Metarbelidae (Lepidoptera, Cossoidea) from the Northeastern Congolian Lowland Forests Ecoregion (Central Africa).

    PubMed

    Lehmann, Ingo

    2014-12-17

    The genera Dianfosseya gen. nov. and Janegoodallia gen. nov. and their single species D. leakeyi sp. nov. and J. davenporti sp. nov. are both described from Isiro, north-eastern Democratic Republic of the Congo, Central Africa (Afrotropical Region). Wing pattern and male genitalia of the new species are depicted and notes on the habitat are presented.

  9. Seroprevalence of Toxoplasma gondii and Neospora caninum in north-eastern Atlantic Harbor seal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antibodies to Toxoplasma gondii and Neospora caninum were determined in serum samples from 47 grey seals (Halichoerus grypus) and 56 harbor seals (Phoca vitulina vitulina) from the Atlantic coasts of United Kingdom and France. Antibodies to T. gondii assayed by the modified agglutination test (MAT) ...

  10. 77 FR 38566 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-28

    ... Omnibus Amendment to implement annual catch limits and accountability measures (76 FR 60606). Among other... the 2012 fishing year (2012 butterfish specifications; 77 FR 16472; March 21, 2012), the Council found... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Framework Adjustment 6...

  11. 76 FR 13887 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish (MSB...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-15

    ... Plan (FMP) (76 FR 8306; February 14, 2011). Butterfish catches have been constrained to low levels... days. ] NMFS policy guidelines for the use of emergency rules (62 FR 44421; August 21, 1997) specify... United States; Atlantic Mackerel, Squid, and Butterfish (MSB) Fishery; Revision of 2011...

  12. 75 FR 5537 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-03

    ... was published on November 12, 2009 (74 FR 58234), and the public comment period for the proposed rule... revised through Amendment 9 to the FMP (Amendment 9) (73 FR 37382, July 1, 2008) to reflect the analytical... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Specifications and Management...

  13. 75 FR 37739 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-30

    ... Butterfish Fisheries in the Federal Register on February 3, 2010 (75 FR 5537). The final rule modified... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Adjustment to the Loligo Trimester 2... Fishing Year (FY) Trimester 2 and 3 Loligo squid quotas. This action complies with the 2010...

  14. 75 FR 1024 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-08

    ..., 2003 (68 FR 27516), NMFS published, at the request of the Council, an ANPR indicating that the Council... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Control Date for Loligo and Illex Squid AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric...

  15. 75 FR 43090 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-23

    ...-2179, fax (978) 281-9135. SUPPLEMENTARY INFORMATION: On June 30, 2010 (75 FR 37739), a temporary rule... equivalent is 10,770 mt. Correction In rule FR Doc. 2010-15933 published on June 30, 2010, (75 FR 37739) make... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Adjustment to the Loligo Trimester...

  16. 75 FR 51683 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-23

    ... FR 5537, February 3, 2010). Section 648.22 requires NMFS to close the directed butterfish fishery in... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the Directed Butterfish..., Squid, and Butterfish Fishery Management Plan (FMP). The procedures for setting the annual...

  17. 76 FR 8306 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-14

    ... management measures was published on November 17, 2010 (75 FR 70187), and the public comment period for the..., established in 2010 by Amendment 10 to the FMP (Amendment 10) (75 FR 11441, March 11, 2010), could result in a...- Atlantic RSA Program through the Federal Register (75 FR 3092, January 19, 2010), and reviewed them in...

  18. 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...

  19. 77 FR 7544 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-13

    ... November 7, 2011 (76 FR ] 68642). The final measures in that action included: A tiered limited access... purposes of Executive Order 12866. Correction In the Federal Register of November 7, 2011, in FR Doc. 2011... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Amendment 11; Correction...

  20. 78 FR 60255 - Fisheries of the Northeastern United States; Atlantic Surfclam and Ocean Quahog Fisheries; Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-01

    ...NMFS informs surfclam and ocean quahog individual transferable quota (ITQ) allocation holders that they will be required to purchase their fishing year 2014 (January 1, 2014-December 31, 2014) cage tags from the National Band and Tag Company. The intent of this notice is to comply with regulations for the Atlantic surfclam and ocean quahog fisheries and to promote efficient distribution of......

  1. 76 FR 23940 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery; Framework Adjustment 22

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-29

    ... to minimize impacts of incidental take of sea turtles as required by the March 14, 2008, Atlantic Sea... management measures to minimize impacts of incidental take of sea turtles that are based on the proposed FY... to Minimize the Impacts of Incidental Take of Sea Turtles Under the Endangered Species Act,...

  2. 78 FR 53404 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-29

    ... INFORMATION: Background On June 9, 2010 (75 FR 32745), the Council published a notice of intent (NOI) to... review by the Secretary of Commerce, was published in the Federal Register on August 12, 2013 (78 FR... Atlantic Herring FMP (Amendment 5). A proposed rule to implement Amendment 5 (78 FR 33020) was published...

  3. 77 FR 26704 - Fisheries of the Northeastern United States; Northeast Multispecies, Monkfish, Atlantic Sea...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-07

    ... United States; Northeast Multispecies, Monkfish, Atlantic Sea Scallop; Amendment 17 AGENCY: National... the Office of Management and Budget of collection-of-information requirements for a days-at-sea credit... Multispecies Fishery Management Plan was published in the Federal Register on March 23, 2012 (77 FR...

  4. 78 FR 51131 - Fisheries of the Northeastern United States; Atlantic Coastal Fisheries Cooperative Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-20

    ... measures, we recently published a proposed rule (78 FR 35217; June 12, 2013), based on Commission... United States; Atlantic Coastal Fisheries Cooperative Management Act Provisions; American Lobster Fishery... provide background information and request public comment on potential changes to Federal American...

  5. 77 FR 74159 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-13

    ... Adjustment 7, are available from: Dr. Christopher M. Moore, Executive Director, Mid-Atlantic Fishery... Mackerel, Squid, and Butterfish (MSB) Fishery Management Plan (FMP) (75 FR 11441, March 11, 2010) as a...: December 10, 2012. Alan Risenhoover, Director, Office of Sustainable Fisheries, performing the...

  6. 77 FR 58507 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-21

    ... Framework Document, are available from: Dr. Christopher M. Moore, Executive Director, Mid- Atlantic Fishery...-9135. SUPPLEMENTARY INFORMATION: Background Amendment 11 to the MSB FMP (76 FR 68642, November 7, 2011... reporting requirements. Dated: September 17, 2012. Alan D. Risenhoover, Director, Office of...

  7. 78 FR 61828 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Framework Adjustment 2 and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-04

    ... United States; Atlantic Herring Fishery; Framework Adjustment 2 and Specifications AGENCY: National... Framework 2 and the 2013-2015 specifications (Framework 2/2013-2015 Specifications) on August 2, 2013 (78 FR... opportunity for providing a steady supply of catch to the market. At the same time, it maintains a...

  8. Nd isotopes in deep-sea corals in the North-eastern Atlantic

    NASA Astrophysics Data System (ADS)

    Copard, Kevin; Colin, Christophe; Douville, Eric; Freiwald, Andre; Gudmundsson, Gudmundur; De Mol, Ben; Frank, Norbert

    2010-09-01

    Neodymium (Nd) concentrations and isotopic signatures of living and fossil deep-sea coral species Lophelia pertusa, Desmophyllum dianthus and Madrepora oculata from the northeast Atlantic Ocean have been investigated in order to test the ability of deep-sea corals to reconstruct the seawater Nd isotopic signature and past changes of ocean circulation in the eastern North Atlantic. Small quantities of Nd—less than 45 ng/g—are incorporated into the aragonite skeleton of living deep-sea corals that dwell at upper intermediate depths throughout the Northeast Atlantic. Rigorous cleaning techniques are needed in order to avoid Nd contamination from manganese-oxide and iron hydroxide coatings. Moreover, Nd isotopic compositions have been measured using thermal ionization mass spectrometry (TIMS) by Nd-oxide method. Our data indicate that the isotopic signatures of modern corals are similar to those of adjacent water masses, implying that deep-sea corals can serve as an archive of the seawater Nd isotopic compositions in the past. The first results from few fully-cleaned fossils corals collected within the Porcupine Seabight and the southwest Rockall Bank reveal significantly higher ɛNd for corals dated between 150 ± 40 and 3060 ± 90 yrs than those of the living corals located in similar areas. This suggests rapid hydrological variations along the eastern margin of the North Atlantic Ocean at intermediate water depth with higher contribution of the Mediterranean Overflow Waters (MOW) or other temperate Atlantic mid-depth water masses (ENACW or NAC) in the past.

  9. Large bio-geographical shifts in the north-eastern Atlantic Ocean: From the subpolar gyre, via plankton, to blue whiting and pilot whales

    NASA Astrophysics Data System (ADS)

    Hátún, H.; Payne, M. R.; Beaugrand, G.; Reid, P. C.; Sandø, A. B.; Drange, H.; Hansen, B.; Jacobsen, J. A.; Bloch, D.

    2009-03-01

    Pronounced changes in fauna, extending from the English Channel in the south to the Barents Sea in the north-east and off Greenland in the north-west, have occurred in the late 1920s, the late 1960s and again in the late 1990s. We attribute these events to exchanges of subarctic and subtropical water masses in the north-eastern North Atlantic Ocean, associated with changes in the strength and extent of the subpolar gyre. These exchanges lead to variations in the influence exerted by the subarctic or Lusitanian biomes on the intermediate faunistic zone in the north-eastern Atlantic. This strong and persistent bottom-up bio-physical link is demonstrated using a numerical ocean general circulation model and data on four trophically connected levels in the food chain - phytoplankton, zooplankton, blue whiting, and pilot whales. The plankton data give a unique basin-scale depiction of these changes, and a long pilot whale record from the Faroe Islands offers an exceptional temporal perspective over three centuries. Recent advances in simulating the dynamics of the subpolar gyre suggests a potential for predicting the distribution of the main faunistic zones in the north-eastern Atlantic a few years into the future, which might facilitate a more rational management of the commercially important fisheries in this region.

  10. Imprint of the Atlantic Multidecadal Oscillation on Tree-Ring Widths in Northeastern Asia since 1568

    PubMed Central

    Wang, Xiaochun; Brown, Peter M.; Zhang, Yanni; Song, Laiping

    2011-01-01

    We present a new tree-ring reconstruction of the Atlantic Multidecadal Oscillation (AMO) spanning 1568–2007 CE from northeast Asia. Comparison of the instrumental AMO index, an existing tree-ring based AMO reconstruction, and this new record show strongly similar annual to multidecadal patterns of variation over the last 440 years. Warm phases of the AMO are related to increases in growth of Scots pine trees and moisture availability in northeast China and central eastern Siberia. Multi-tape method (MTM) and cross-wavelet analyses indicate that robust multidecadal (∼64–128 years) variability is present throughout the new proxy record. Our results have important implications concerning the influence of North Atlantic sea surface temperatures on East Asian climate, and provide support for the possibility of an AMO signature on global multidecadal climate variability. PMID:21818380

  11. Multiple Beneficial Lipids Including Lecithin Detected in the Edible Invasive Mollusk Crepidula fornicata from the French Northeastern Atlantic Coast

    PubMed Central

    Dagorn, Flore; Buzin, Florence; Couzinet-Mossion, Aurélie; Decottignies, Priscilla; Viau, Michèle; Rabesaotra, Vony; Barnathan, Gilles; Wielgosz-Collin, Gaëtane

    2014-01-01

    The invasive mollusk Crepidula fornicata, occurring in large amounts in bays along the French Northeastern Atlantic coasts, may have huge environmental effects in highly productive ecosystems where shellfish are exploited. The present study aims at determining the potential economic value of this marine species in terms of exploitable substances with high added value. Lipid content and phospholipid (PL) composition of this mollusk collected on the Bourgneuf Bay were studied through four seasons. Winter specimens contained the highest lipid levels (5.3% dry weight), including 69% of PLs. Phosphatidylcholine (PC) was the major PL class all year, accounting for 63.9% to 88.9% of total PLs. Consequently, the winter specimens were then investigated for PL fatty acids (FAs), and free sterols. Dimethylacetals (DMAs) were present (10.7% of PL FA + DMA mixture) revealing the occurrence of plasmalogens. More than forty FAs were identified, including 20:5n-3 (9.4%) and 22:6n-3 (7.3%) acids. Fourteen free sterols were present, including cholesterol at 31.3% of the sterol mixture and about 40% of phytosterols. These data on lipids of C. fornicata demonstrate their positive attributes for human nutrition and health. The PL mixture, rich in PC and polyunsaturated FAs, offers an interesting alternative source of high value-added marine lecithin. PMID:25532566

  12. Source and delivery of nutrients to receiving waters in the Northeastern and Mid-Atlantic regions of the United States

    USGS Publications Warehouse

    Moore, Richard B.; Johnston, Criag M.; Smith, Richard A.; Milstead, Bryan

    2011-01-01

    This study investigates nutrient sources and transport to receiving waters, in order to provide spatially detailed information to aid water-resources managers concerned with eutrophication and nutrient management strategies. SPAtially Referenced Regressions On Watershed attributes (SPARROW) nutrient models were developed for the Northeastern and Mid-Atlantic (NE US) regions of the United States to represent source conditions for the year 2002. The model developed to examine the source and delivery of nitrogen to the estuaries of nine large rivers along the NE US Seaboard indicated that agricultural sources contribute the largest percentage (37%) of the total nitrogen load delivered to the estuaries. Point sources account for 28% while atmospheric deposition accounts for 20%. A second SPARROW model was used to examine the sources and delivery of phosphorus to lakes and reservoirs throughout the NE US. The greatest attenuation of phosphorus occurred in lakes that were large relative to the size of their watershed. Model results show that, within the NE US, aquatic decay of nutrients is quite limited on an annual basis and that we especially cannot rely on natural attenuation to remove nutrients within the larger rivers nor within lakes with large watersheds relative to the size of the lake.

  13. Influences of bioavailability, trophic position, and growth on methylmercury in hakes (Merluccius merluccius) from Northwestern Mediterranean and Northeastern Atlantic.

    PubMed

    Cossa, D; Harmelin-Vivien, M; Mellon-Duval, C; Loizeau, V; Averty, B; Crochet, S; Chou, L; Cadiou, J-F

    2012-05-01

    Methylmercury (MeHg) determinations in hake, its food-chain, and the surrounding waters and sediments allowed us to show that the higher length or age normalized mercury concentrations of Northwestern Mediterranean (Gulf of Lions: GoL) muscle hakes compared to its Northeastern Atlantic (Bay of Biscay: BoB) counterpart are due to both biotic and abiotic differences between their ecosystems. Bioenergetic modeling reveals that the slower growth rate of Mediterranean hake favors the MeHg bioaccumulation in the fish muscle and explains most of the difference between GOL and BoB hake populations. In addition, the waters of the Mediterranean hake habitat favor a higher MeHg exposition, due to the upper position of the thermohalocline, where MeHg is formed. Furthermore, we show that, within the Mediterranean hake population, a major increase in the biomagnification power (the slope of the relationships between logMeHg and δ(15)N), from 0.36 up to 1.12, occurs when individuals enter adulthood, resulting from the combined effects of lowering growth rate and change in feeding habits. Finally, δ(15)N normalized Hg concentrations indicate that the highest Hg concentrations are for hake from the shelf edge and the lowest are for hake from the Rhône prodelta area, suggesting a lower Hg bioavailability in inshore environments, consistent with MeHg distributions in water, sediment, and preys. PMID:22482912

  14. Source and Delivery of Nutrients to Receiving Waters in the Northeastern and Mid-Atlantic Regions of the United States

    USGS Publications Warehouse

    Moore, R.B.; Johnston, C.M.; Smith, R.A.; Milstead, B.

    2011-01-01

    This study investigates nutrient sources and transport to receiving waters, in order to provide spatially detailed information to aid water-resources managers concerned with eutrophication and nutrient management strategies. SPAtially Referenced Regressions On Watershed attributes (SPARROW) nutrient models were developed for the Northeastern and Mid-Atlantic (NE US) regions of the United States to represent source conditions for the year 2002. The model developed to examine the source and delivery of nitrogen to the estuaries of nine large rivers along the NE US Seaboard indicated that agricultural sources contribute the largest percentage (37%) of the total nitrogen load delivered to the estuaries. Point sources account for 28% while atmospheric deposition accounts for 20%. A second SPARROW model was used to examine the sources and delivery of phosphorus to lakes and reservoirs throughout the NE US. The greatest attenuation of phosphorus occurred in lakes that were large relative to the size of their watershed. Model results show that, within the NE US, aquatic decay of nutrients is quite limited on an annual basis and that we especially cannot rely on natural attenuation to remove nutrients within the larger rivers nor within lakes with large watersheds relative to the size of the lake. ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

  15. Lidar Observations of Tropospheric Aerosols Over Northeastern South Africa During the ARREX and SAFARI-2000 Dry Season Experiments

    NASA Technical Reports Server (NTRS)

    Campbell, James R.; Welton, Ellsworth J.; Spinhirne, James D.; Ji, Qiang; Tsay, Si-Chee; Piketh, Stuart J.; Barenbrug, Marguerite; Holben, Brent; Starr, David OC. (Technical Monitor)

    2002-01-01

    During the ARREX-1999 and SAFARI-2000 Dry Season experiments a micropulse lidar (523 nm) instrument was operated at the Skukuza Airport in northeastern South Africa. The Mar was collocated with a diverse array of passive radiometric equipment. For SAFARI-2000 the processed Mar data yields a daytime time-series of layer mean/derived aerosol optical properties, including extinction-to-backscatter ratios and vertical extinction cross-section profile. Combined with 523 run aerosol optical depth and spectral Angstrom exponent calculations from available CIMEL sun-photometer data and normalized broadband flux measurements the temporal evolution of the near surface aerosol layer optical properties is analyzed for climatological trends. For the densest smoke/haze events the extinction-to-backscatter ratio is found to be between 60-80/sr, and corresponding Angstrom exponent calculations near and above 1.75. The optical characteristics of an evolving smoke event from SAFARI-2000 are extensively detailed. The advecting smoke was embedded within two distinct stratified thermodynamic layers, causing the particulate mass to advect over the instrument array in an incoherent manner on the afternoon of its occurrence. Surface broadband flux forcing due to the smoke is calculated, as is the evolution in the vertical aerosol extinction profile as measured by the Han Finally, observations of persistent elevated aerosol during ARREX-1999 are presented and discussed. The lack of corroborating observations the following year makes these observation; both unique and noteworthy in the scope of regional aerosol transport over southern Africa.

  16. Preliminary report on geology along Atlantic Continental Margin of northeastern United States

    USGS Publications Warehouse

    Minard, J.P.; Perry, W.J.; Weed, E.G.A.; Rhodehamel, E.C.; Robbins, E.I.; Mixon, R.B.

    1974-01-01

    The U.S. Geological Survey is conducting a geologic and geophysical study of the northeastern United States outer continental shelf and the adjacent slope from Georges Bank to Cape Hatteras. The study also includes the adjacent coastal plain because it is a more accessible extension of the shelf. The total study area is about 324,000 sq km, of which the shelf and slope constitute about 181,000 sq km and the coastal plain constitutes 143,000 sq km. The shelf width ranges from about 30 km at Cape Hatteras to about 195 km off Raritan Bay and on Georges Bank. Analyses of bottom samples make it possible to construct a preliminary geologic map of the shelf and slope to a water depth of 2,000 m. The oldest beds cropping out in the submarine canyons and on the slope are of early ate Cretaceous age. Beds of Early Cretaceous and Jurassic age are present in deep wells onshore and probably are present beneath the shelf in the area of this study. Such beds are reported beneath the Scotian shelf on the northeast where they include limestone, salt, and anhydrite. Preliminary conclusions suggest a considerably thicker Mesozoic sedimentary sequence than has been described previously. The region is large; the sedimentary wedge is thick; structures seem favorable; and the hydrocarbon potential may be considerable.

  17. Cold season Africa-Asia multidecadal teleconnection pattern and its relation to the Atlantic multidecadal variability

    NASA Astrophysics Data System (ADS)

    Sun, Cheng; Li, Jianping; Ding, Ruiqiang; Jin, Ze

    2016-08-01

    A prominent teleconnection pattern of multidecadal variability of cold season (November to April) upper-level atmospheric circulation over North Africa and Eurasia (NA-EA) is revealed by empirical orthogonal function analysis of the Twentieth Century Reanalysis data. This teleconnection pattern is characterized by an eastward propagating wave train with a zonal wavenumber of 5-6 between 20° and 40°N, extending from the northwest coast of Africa to East Asia, and thus is referred to as the Africa-Asia multidecadal teleconnection pattern (AAMT). One-point correlation maps show that the teleconnectivity of AAMT is strong and further demonstrate the existence of the AAMT. The AAMT shapes the spatial structure of multidecadal change in atmospheric circulation over the NA-EA region, and in particular the AAMT pattern and associated fields show similar structures to the change occurring around the early 1960s. A strong in-phase relationship is observed between the AAMT and Atlantic multidecadal variability (AMV) and this connection is mainly due to Rossby wave dynamics. Barotropic modeling results suggest that the upper-level Rossby wave source generated by the AMV can excite the AAMT wave train, and Rossby wave ray tracing analysis further highlights the role of the Asian jet stream in guiding the wave train to East Asia. The AAMT acts as an atmospheric bridge conveying the influence of AMV onto the downstream multidecadal climate variability. The AMV is closely related to the coordinated change in surface and tropospheric air temperatures over Northwest Africa, the Arabian Peninsula and Central China, which may result from the adiabatic expansion/compression of air associated with the AAMT.

  18. Evidence of Northeastern Atlantic Ocean Acidification Recorded by Boron Isotopes on Deep-sea Coral Madrepora oculata

    NASA Astrophysics Data System (ADS)

    Gonzalez-Roubaud, C.; Douville, E.; Bordier, L.; Louvat, P.; Gaillardet, J.; Hall-Spencer, J. M.; Juillet-Leclerc, A.

    2011-12-01

    measurements of carbon and oxygen isotopes, as well as the comparison of boron variability with other physiological parameters such as coral density, will allow us to confirm the drop on seawater pH on the last decades for the northeastern intermediate Atlantic waters.

  19. NEAMWave12: The First Tsunami Exercise in the North-eastern Atlantic, the Mediterranean and Connected Seas

    NASA Astrophysics Data System (ADS)

    Necmioglu, Ocal; Matias Matias, Luis; Schindelé, François; Behrens, Jörn; Tinti, Stefano; Chouliaras, Gerasimos; Melis, Nicos; Carrilho, Fernando; Santoro, Francesca; Rudloff, Alexander; Crochet, Emilie; Gonzalez, Mauricio

    2013-04-01

    The first tsunami exercise of the Tsunami Early Warning and Mitigation System in the North-eastern Atlantic, the Mediterranean and connected seas (NEAMTWS) has been conducted on 27-28 November 2012 involving 19 of the 39 member countries of the Intergovernmental Coordination Group (ICG) for NEAMTWS. NEAMWave12 involved the simulation of the assessment of a tsunami, based on an earthquake-driven scenario followed by alert message dissemination by Candidate Tsunami Watch Provider (CTWP) (Phase A) and continued with the simulation of the National Tsunami Warning Center's/Tsunami Warning Focal Point's (NTWC/TWFP) and Civil Protection Authoritie's (CPA) actions (Phase B), as soon as the message produced in Phase A has been received. There were four earthquake triggered tsunami scenarios in NEAMWave12 in different parts of the NEAM Region, where each CTWP (CENALT-France, NOA-Greece, IPMA-Portugal and KOERI-Turkey) was responsible for a single scenario. The CENALT Scenario was based on a plausible worst-case scenario of magnitude 7.5 along the Western Mediterranean Algerian margin at a fault located close to 21-22 August 1856 Jijel earthquakes. The NOA scenario was based on an earthquake similar to the well-known Amorgos earthquake, which was followed by a tsunami that devastated the Aegean Sea on 9 July 1956. The IPMA scenario was based on the 1 November 1755 Lisbon event with the assumption that the event represents the worst-case tsunami scenario impacting the NE Atlantic region. Finally, the KOERI scenario was based on a Mw=8.4 worst-case interpretation of the 8 August 1303 Crete and Dodecanese Islands earthquake resulting in destructive inundation in the Eastern Mediterranean. Initial evaluation of the exercise indicates that all CTWPs successfully participated in the exercise, where existing operational and some future prototype systems were utilized. System end-users (NTWC/TWFP/CPA) benefited from the exercise considerably, demonstrating the first successful test

  20. Improving estimates of surface water radiocarbon reservoir ages in the northeastern Atlantic Ocean.

    NASA Astrophysics Data System (ADS)

    Greenop, Rosanna; Burke, Andrea; Rae, James; Austin, William; Reimer, Paula; Blaauw, Maarten; Crocker, Anya; Chalk, Thomas; Barker, Stephen; Knutz, Paul; Hall, Ian

    2016-04-01

    Radiocarbon measurements from foraminifera in marine sediment cores are widely used to constrain age models and the timing of paleoceanographic events, as well as past changes in ocean circulation and carbon cycling. However, the use of radiocarbon for both dating and palaeoceanographic applications is limited in sediment cores by a lack of knowledge about the surface ocean radiocarbon reservoir age and how it varies in both space and time. Typically, to convert a planktic radiocarbon age into a calendar age, an assumed constant reservoir age is applied. However, there is mounting evidence to suggest that this assumption of constant reservoir age through time is an oversimplification, particularly for the high latitude oceans during the cold climates of the last glacial and deglacial periods. Here we present new high-resolution radiocarbon records together with tephra tie points and 230-thorium (230Th) constrained sedimentation rates to improve estimates of radiocarbon reservoir age in the Northeast Atlantic Ocean. In addition we will explore the impact of the new reservoir ages for both the age models of the cores studied, as well as the palaeoceanographic implications of these reservoir age changes during intervals of rapid climate change over the past 40,000 years.

  1. Preliminary observation on sexual maturity of black anglerfish (Lophius budegassa) in north-eastern Atlantic waters

    NASA Astrophysics Data System (ADS)

    Landa, Jorge; Antolínez, Ana; Ámez, Marco A.; Barrado, Joaquín; Castro, Begoña; Cañás, Lucía; Autón, Urbano; Fariña, Antonio C.; Hernández, Carmen

    2014-08-01

    The reproduction of black anglerfish (Lophius budegassa) was studied from samples collected during 5 years, from January 2006 to December 2010, in Celtic Sea, West and South of Ireland (ICES Div. VIIb-k) and Northern Spanish Atlantic waters (ICES Div. VIIIc-IXa). A total of 1167 specimens (4-99 cm) were sampled. The sex ratio, the spawning period and the maturity ogives by length were studied. The sex ratio in both areas studied varied with length, and it was close to 1:1 (male:female), 1:1.22 (54.90% of females) in Div. VIIb-k, and 1:1.01 (50.30% of females) in Div. VIIIc-IXa. A seasonal variation in sex ratio by length was observed at first time in Div VIIIc-IXa, with a very low proportion of intermediate sized females (40-60 cm) in the second semester. A seasonal reproductive migratory behavior is discussed. The spawning period was between December and July in Div. VIIIc-IXa. Spawning males were found throughout the year, but fewer spawning females, as in previous studies. The L50 values were estimated in Div. VIIIc-IXa: 38.2 cm for combined sexes, 36.0 cm for males and 53.0 cm for females. These values of sex ratio and L50 are similar to those obtained in closed areas studied.

  2. Feather mites (Acari, Astigmata) associated with birds in an Atlantic Forest fragment in Northeastern Brazil.

    PubMed

    Silva, H M; Hernandes, F A; Pichorim, M

    2015-08-01

    The present study reports associations between feather mites (Astigmata) and birds in an Atlantic Forest fragment in Rio Grande do Norte state, in Brazil. In the laboratory, mites were collected through visual examination of freshly killed birds. Overall, 172 individuals from 38 bird species were examined, between October 2011 and July 2012. The prevalence of feather mites was 80.8%, corresponding to 139 infested individuals distributed into 30 species and 15 families of hosts. Fifteen feather mite taxa could be identified to the species level, sixteen to the genus level and three to the subfamily level, distributed into the families Analgidae, Proctophyllodidae, Psoroptoididae, Pteronyssidae, Xolalgidae, Trouessartiidae, Falculiferidae and Gabuciniidae. Hitherto unknown associations between feather mites and birds were recorded for eleven taxa identified to the species level, and nine taxa were recorded for the first time in Brazil. The number of new geographic records, as well as the hitherto unknown mite-host associations, supports the high estimates of diversity for feather mites of Brazil and show the need for research to increase knowledge of plumicole mites in the Neotropical region.

  3. Middle Tropospheric Cyclonic Vortex in Northeastern Brazil and the Tropical Atlantic

    NASA Astrophysics Data System (ADS)

    Fedorova, Natalia; dos Santos, Deydila Michele Bonfim; Segundo, Márcio Maciel Lopes; Levit, Vladimir

    2016-08-01

    Middle Tropospheric Cyclonic Vortices (MTCVs) are observed in the tropical region of the Southern Atlantic, with their center located between 700 and 400 hPa. The analysis of MTCVs' frequencies, location and duration over 3 years (2008-2010) was the principal goal of the present study. MTCVs have been identified and analyzed using the NCEP reanalysis data at the nine levels. About 232 MTCVs were observed each year. More frequently the MTCV centers were observed at the 700 hPa (41 % of all days with vortex). MTCVs were registered during all seasons (6-12 MTCVs per month, on average). The MTCVs' frequency only slightly varied over seasons with the lowest value in spring. MTCVs were predominantly (71 %) short and lasted less than 12 h. The vortices persisting longer than 30 h were detected more frequently in summer and rarely in autumn. MTCVs were observed more frequently (86 %) between 6 and 18°S over the ocean. About nine events per year were observed over the continental region between 9 and 21°S in summer and winter, and between 4 and 11°S in autumn and spring. One MTCV event is considered in detail.

  4. Taxonomic and functional profiles of soil samples from Atlantic forest and Caatinga biomes in northeastern Brazil

    PubMed Central

    Pacchioni, Ralfo G; Carvalho, Fabíola M; Thompson, Claudia E; Faustino, André L F; Nicolini, Fernanda; Pereira, Tatiana S; Silva, Rita C B; Cantão, Mauricio E; Gerber, Alexandra; Vasconcelos, Ana T R; Agnez-Lima, Lucymara F

    2014-01-01

    Although microorganisms play crucial roles in ecosystems, metagenomic analyses of soil samples are quite scarce, especially in the Southern Hemisphere. In this work, the microbial diversity of soil samples from an Atlantic Forest and Caatinga was analyzed using a metagenomic approach. Proteobacteria and Actinobacteria were the dominant phyla in both samples. Among which, a significant proportion of stress-resistant bacteria associated to organic matter degradation was found. Sequences related to metabolism of amino acids, nitrogen, and DNA and stress resistance were more frequent in Caatinga soil, while the forest sample showed the highest occurrence of hits annotated in phosphorous metabolism, defense mechanisms, and aromatic compound degradation subsystems. The principal component analysis (PCA) showed that our samples are close to the desert metagenomes in relation to taxonomy, but are more similar to rhizosphere microbiota in relation to the functional profiles. The data indicate that soil characteristics affect the taxonomic and functional distribution; these characteristics include low nutrient content, high drainage (both are sandy soils), vegetation, and exposure to stress. In both samples, a rapid turnover of organic matter with low greenhouse gas emission was suggested by the functional profiles obtained, reinforcing the importance of preserving natural areas. PMID:24706600

  5. Molecular systematics of the genus Holothuria in the Mediterranean and Northeastern Atlantic and a molecular clock for the diversification of the Holothuriidae (Echinodermata: Holothuroidea).

    PubMed

    Borrero-Pérez, Giomar Helena; Gómez-Zurita, Jesús; González-Wangüemert, Mercedes; Marcos, Concepción; Pérez-Ruzafa, Angel

    2010-11-01

    This work investigates the systematics of the genus Holothuria in the Mediterranean Sea and Northeastern Atlantic in the light of a wider molecular phylogenetic hypothesis of Holothuriidae, and it also provides a time-scale for the family diversification using mitochondrial markers and the molecular clock hypothesis. The subgenera Holothuria and Roweothuria are retrieved as paraphyletic. At least four separate lineages, with quite different time frameworks were identified. There are at least three species with an apparent long evolutionary history, H. forskali, H. sanctori and H. impatiens and six species belonging to Holothuria, Roweothuria and Vaneyothuria, which have diverged relatively recently.

  6. A GCM Study of Responses of the Atmospheric Water Cycle of West Africa and the Atlantic to Saharan Dust Radiative Forcing

    NASA Technical Reports Server (NTRS)

    Lau, K. M.; Kim, K. M.; Sud, Y. C.; Walker, G. K.

    2009-01-01

    The responses of the atmospheric water cycle and climate of West Africa and the Atlantic to radiative forcing of Saharan dust are studied using the NASA finite volume general circulation model (fvGCM), coupled to a mixed layer ocean. We find evidence of an "elevated heat pump" (EHP) mechanism that underlines the responses of the atmospheric water cycle to dust forcing as follow. During the boreal summerr, as a result of large-scale atmospheric feedback triggered by absorbing dust aerosols, rainfall and cloudiness are ehanIed over the West Africa/Eastern Atlantic ITCZ, and suppressed over the West Atlantic and Caribbean region. Shortwave radiation absorption by dust warms the atmosphere and cools the surface, while longwave has the opposite response. The elevated dust layer warms the air over West Africa and the eastern Atlantic. As the warm air rises, it spawns a large-scale onshore flow carrying the moist air from the eastern Atlantic and the Gulf of Guinea. The onshore flow in turn enhances the deep convection over West Africa land, and the eastern Atlantic. The condensation heating associated with the ensuing deep convection drives and maintains an anomalous large-scale east-west overturning circulation with rising motion over West Africa/eastern Atlantic, and sinking motion over the Caribbean region. The response also includes a strengthening of the West African monsoon, manifested in a northward shift of the West Africa precipitation over land, increased low-level westerlies flow over West Africa at the southern edge of the dust layer, and a near surface westerly jet underneath the dust layer overr the Sahara. The dust radiative forcing also leads to significant changes in surface energy fluxes, resulting in cooling of the West African land and the eastern Atlantic, and warming in the West Atlantic and Caribbean. The EHP effect is most effective for moderate to highly absorbing dusts, and becomes minimized for reflecting dust with single scattering albedo at0

  7. Chemical Characteristics of Continental Outflow Over the Tropical South Atlantic Ocean from Brazil and Africa

    NASA Technical Reports Server (NTRS)

    Talbot, R. W.; Bradshaw, J. D.; Sandholm, S. T.; Smyth, S.; Blake, D. R.; Blake, N. R.; Sachse, G. W.; Collins, J. E.; Heikes, B. G.; Anderson, B. E.; Gregory, G. L.; Singh, H. B.; Lefer, B. L.; Bachmeier, A. S.

    1996-01-01

    The chemical characteristics of air parcels over the tropical South Atlantic during September - October 1992 are summarized by analysis of aged marine and continental outflow classifications. Positive correlations between CO and CH3CL and minimal enhancements of C2CL40, and various ChloroFluoroCarbon (CFC) species in air parcels recently advected over the South Atlantic basin strongly suggest an impact on tropospheric chemistry from biomass burning on adjacent continental areas of Brazil and Africa. Comparison of the composition of aged Pacific air with aged marine air over the South Atlantic basin from 0.3 to 12.5 km altitude indicates potential accumulation of long-lived species during the local dry season. This may amount to enhancements of up to two-fold for C2H6, 30% for CO, and 10% for CH3Cl. Nitric oxide and NO(x) were significantly enhanced (up to approx. 1 part per billion by volume (ppbv)) above 10 km altitude and poorly correlated with CO and CH3Cl. In addition, median mixing ratios of NO and NO(x) were essentially identical in aged marine and continental outflow air masses. It appears that in addition to biomass burning, lightning or recycled reactive nitrogen may be an important source of NO(x) to the upper troposphere. Methane exhibited a monotonic increase with altitude from approx. 1690 to 1720 ppbv in both aged marine and continental outflow air masses. The largest mixing ratios in the upper troposphere were often anticorrelated with CO, CH3Cl, and CO2, suggesting CH, contributions from natural sources. We also argue, based on CH4/CO ratios and relationships with various hydrocarbon and CFC species, that inputs from biomass burning and the northern hemisphere are unlikely to be the dominant sources of CO, CH4 and C2H6 in aged marine air. Emissions from urban areas would seem to be necessary to account for the distribution of at least CH4 and C2H6. Over the African and South American continents an efficient mechanism of convective vertical transport

  8. Swim speed, behavior, and movement of North Atlantic right whales (Eubalaena glacialis) in coastal waters of northeastern Florida, USA.

    PubMed

    Hain, James H W; Hampp, Joy D; McKenney, Sheila A; Albert, Julie A; Kenney, Robert D

    2013-01-01

    In a portion of the coastal waters of northeastern Florida, North Atlantic right whales (Eubalaena glacialis) occur close to shore from December through March. These waters are included within the designated critical habitat for right whales. Data on swim speed, behavior, and direction of movement--with photo-identification of individual whales--were gathered by a volunteer sighting network working alongside experienced scientists and supplemented by aerial observations. In seven years (2001-2007), 109 tracking periods or "follows" were conducted on right whales during 600 hours of observation from shore-based observers. The whales were categorized as mother-calf pairs, singles and non-mother-calf pairs, and groups of 3 or more individuals. Sample size and amount of information obtained was largest for mother-calf pairs. Swim speeds varied within and across observation periods, individuals, and categories. One category, singles and non mother-calf pairs, was significantly different from the other two--and had the largest variability and the fastest swim speeds. Median swim speed for all categories was 1.3 km/h (0.7 kn), with examples that suggest swim speeds differ between within-habitat movement and migration-mode travel. Within-habitat right whales often travel back-and-forth in a north-south, along-coast, direction, which may cause an individual to pass by a given point on several occasions, potentially increasing anthropogenic risk exposure (e.g., vessel collision, fishing gear entanglement, harassment). At times, mothers and calves engaged in lengthy stationary periods (up to 7.5 h) that included rest, nursing, and play. These mother-calf interactions have implications for communication, learning, and survival. Overall, these behaviors are relevant to population status, distribution, calving success, correlation to environmental parameters, survey efficacy, and human-impacts mitigation. These observations contribute important parameters to conservation biology

  9. Micropulse lidar observations of tropospheric aerosols over northeastern South Africa during the ARREX and SAFARI 2000 dry season experiments

    NASA Astrophysics Data System (ADS)

    Campbell, James R.; Welton, Ellsworth J.; Spinhirne, James D.; Ji, Qiang; Tsay, Si-Chee; Piketh, Stuart J.; Barenbrug, Marguerite; Holben, Brent N.

    2003-07-01

    During the Aerosol Recirculation and Rainfall Experiment (ARREX 1999) and Southern African Regional Science Initiative (SAFARI 2000) dry season experiments, a micropulse lidar (523 nm) instrument was operated at the Skukuza Airport in northeastern South Africa. The lidar was colocated with a diverse array of passive radiometric equipment. For SAFARI 2000, a daytime time series of layer mean aerosol optical properties, including layer mean extinction-to-backscatter ratios and vertical extinction cross-section profiles are derived from the synthesis of the lidar data and aerosol optical depths from available AERONET Sun photometer data. Combined with derived spectral Angstrom exponents, normalized broadband flux measurements, and calculated air mass back-trajectories, the temporal evolution of the surface aerosol layer optical properties is analyzed for climatological trends. For dense biomass smoke events the extinction-to-backscatter ratio is between 50 and 90 sr, and corresponding spectral Angstrom exponent values are between 1.50 and 2.00. Observations of an advecting smoke event during SAFARI 2000 are shown. The smoke was embedded within two distinct stratified thermodynamic layers causing the particulate mass to advect over the instrument array in an incoherent manner on the afternoon of 1 September 2000. Significant surface broadband flux forcing of over -50 W/m2 was measured in this event. The evolution of the vertical aerosol extinction profile is profiled using the lidar data. Finally, observations of persistent elevated aerosol layers during ARREX 1999 are presented and discussed. Back-trajectory analyses combined with lidar and Sun photometer measurements indicate the likelihood for these aerosols being the result of long-range particulate transport from the southern and central South America.

  10. An Archeomagnetic Record From Southern Africa and its Bearing on the History of the South Atlantic Anomaly

    NASA Astrophysics Data System (ADS)

    Grigsby, M. R.; Tarduno, J. A.; Cottrell, R. D.; Huffman, T. N.; Watkeys, M. K.; Blackman, E.

    2015-12-01

    The low intensity area in Earth's recent magnetic field that spans the southern Atlantic Ocean, Africa and South America is commonly called the South Atlantic Anomaly (SAA). Many believe the SAA is linked to the dramatic decay of the dipole geomagnetic field intensity during the last 160 years, and the growth of a reversed core flux patch beneath South Africa. The dipole field decay has even motivated speculation that Earth is heading toward a geomagnetic field reversal. But understanding these phenomena within the context of longer-term geomagnetic history has been limited by a lack of Southern Hemisphere archeomagnetic data. We have recently presented the first archeomagnetic data from Iron Age sites of southern Africa (~1000-1650 AD) (Tarduno et al., 2014, 2015). Magnetic data show a sharp intensity drop at ~1300 AD, at a rate comparable to modern field changes in the SAA, (but to lower values). These changes motivated our conceptual model whereby the recurrence of low field values reflects magnetic flux expulsion from the core, promoted by the unusual core-mantle boundary composition and structure beneath southern Africa defined by seismology (specifically the African Large Low Velocity Seismic Province, or LLVSP). Because the African LLVSP is a longstanding structure, we expect this region to be a steady site of flux expulsion, and perhaps the triggering site for reversals, on time scales of millions of years. Here we discuss our ongoing efforts to extend the archeomagnetic record from southern Africa back in time, and further develop the flux expulsion- African LLVSP hypothesis, through new sampling and paleomagnetic analyses of Iron Age burnt huts, grain bins and kraals from South Africa, Zimbabwe and Botswana.

  11. 76 FR 36511 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab; Amendment 3

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-22

    ... United States; Atlantic Deep-Sea Red Crab; Amendment 3 AGENCY: National Marine Fisheries Service (NMFS... Fishery Management Council (Council) has submitted Amendment 3 to the Atlantic Deep-Sea Red Crab Fishery... envelope, ``Comments on Red Crab Amendment 3.'' Instructions: All comments received are part of the...

  12. An archeomagnetic record from southern Africa and its bearing on the history of the South Atlantic Anomaly

    NASA Astrophysics Data System (ADS)

    Tarduno, John; Cottrell, Rory; Huffman, Thomas; Watkeys, Michael; Grigsby, Miriam; Blackman, Eric

    2016-04-01

    The paucity of Southern Hemisphere archeomagnetic data limits the resolution of paleosecular variation models, while at the same time important changes in the modern and historical field, including the recent dipole decay, appear to originate in this region. We have recently presented the first archeomagnetic data from Iron Age sites of southern Africa (˜1000-1650 AD) (Tarduno et al., Nature Communications, 2015). Magnetic data show a sharp intensity drop at ˜1300 AD, at a rate comparable to modern field changes in the South Atlantic Anomaly (SAA), but to lower values. These changes motivated our conceptual model whereby the recurrence of low field values reflects magnetic flux expulsion from the core, promoted by the unusual core-mantle boundary composition and structure beneath southern Africa as defined by seismology (specifically the African Large Low Velocity Seismic Province, or LLVSP). Because the African LLVSP is a longstanding structure, we expect this region to be a steady site of flux expulsion, and perhaps the triggering site for reversals, on time scales of millions of years. Here we discuss our ongoing efforts to extend the archeomagnetic record from southern Africa back in time, and further develop the flux expulsion- African LLVSP hypothesis, through new sampling and paleomagnetic analyses of Iron Age burnt huts, grain bins and kraals from South Africa, Zimbabwe and Botswana. Our preliminary analyses define a loop in the archeomagnetic curve for southern Africa between ca. 400 and 1000 AD, absent in predictions from available paleosecular variation models, that might record another flux expulsion episode.

  13. New Perspectives from Satellite and Profile Observations on Tropospheric Ozone over Africa and the Adjacent Oceans: An Indian-Atlantic Ocean Link to tbe "Ozone Paradox"

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Witte, Jacquelyn C.; Diab, Roseanne D.; Thouret, Valerie; Sauvage, Bastien; Chatfield, B.; Guan, Hong

    2004-01-01

    In the past few years, tropospheric ozone observations of Africa and its adjacent ocenas have been greatly enhanced by high resolution (spatial and temporal) satellite measurements and profile data from aircraft (MOZAIC) and balloon-borne (SHADOZ) soundings. These views have demonstrated for the first time the complexity of chemical-dynamical interactions over the African continent and the Indian and Atlantic Oceans. The tropical Atlantic "ozone paradax" refers to the observation that during the season of maximum biomass burning in west Africa north of the Intertropical Convergence Zone (ITCZ), the highest tropospheric ozone total column occurs south of the ITCZ over the tropical Atlantic. The longitudinal view of tropospheric ozone in the southern tropics from SHADOZ (Southern Hemisphere Additional Ozonesondes) soundings shown the persistence of a "zonal-wave one" pattern that reinforces the "ozone paradox". These ozone features interact with dynamics over southern and northern Africa where anthropogenic sources include the industrial regions of the South African Highveld and Mideastern-Mediterranean influences, respectively. Our newest studies with satellites and soundings show that up to half the ozone pollution over the Atlantic in the January-March "paradox" period may originate from south Asian pollution. Individual patches of pollurion over the Indian Ocean are transported upward by convective mixing and are enriched by pyrogenic, biogenic sources and lightning as they cross Africa and descend over the Atlantic. In summary, local sources, intercontinental import and export and unique regional transport patterns put Africa at a crossroads of troposheric ozone influences.

  14. Measurements of the stable carbon isotope composition of dissolved inorganic carbon in the Northeastern Atlantic and Nordic Seas during summer 2012

    NASA Astrophysics Data System (ADS)

    Humphreys, M. P.; Achterberg, E. P.; Griffiths, A. M.; McDonald, A.; Boyce, A. J.

    2015-01-01

    The stable carbon isotope composition of dissolved inorganic carbon (δ13CDIC) in seawater was measured in samples collected during two cruises in the Northeastern Atlantic and Nordic Seas from June to August 2012. One cruise was part of the UK Ocean Acidification research programme, and the other was a repeat hydrographic transect of the Extended Ellett Line. In combination with measurements made of various other variables on these and other cruises, these data can be used to constrain the anthropogenic component of DIC in the interior ocean, and also assist in determining the influence of biological carbon uptake on surface ocean carbonate chemistry. The measurements have been processed, quality-controlled and submitted to an in-preparation global compilation of seawater δ13CDIC data, and are available from the British Oceanographic Data Centre. The observed δ13CDIC values fall in a range from -0.58 to +2.37‰, relative to the Vienna Peedee Belemnite standard. From duplicate samples collected during both cruises, the precision for the 552 results is 0.07‰, which is similar to other published studies of this kind. Data doi:10.5285/09760a3a-c2b5-250b-e053-6c86abc037c0 (Northeastern Atlantic), doi:10.5285/09511dd0-51db-0e21-e053-6c86abc09b95 (Nordic Seas).

  15. Genetic Diversity of White Sharks, Carcharodon carcharias, in the Northwest Atlantic and Southern Africa.

    PubMed

    O'Leary, Shannon J; Feldheim, Kevin A; Fields, Andrew T; Natanson, Lisa J; Wintner, Sabine; Hussey, Nigel; Shivji, Mahmood S; Chapman, Demian D

    2015-01-01

    The white shark, Carcharodon carcharias, is both one of the largest apex predators in the world and among the most heavily protected marine fish. Population genetic diversity is in part shaped by recent demographic history and can thus provide information complementary to more traditional population assessments, which are difficult to obtain for white sharks and have at times been controversial. Here, we use the mitochondrial control region and 14 nuclear-encoded microsatellite loci to assess white shark genetic diversity in 2 regions: the Northwest Atlantic (NWA, N = 35) and southern Africa (SA, N = 131). We find that these 2 regions harbor genetically distinct white shark populations (Φ ST = 0.10, P < 0.00001; microsatellite F ST = 0.1057, P < 0.021). M-ratios were low and indicative of a genetic bottleneck in the NWA (M-ratio = 0.71, P < 0.004) but not SA (M-ratio = 0.85, P = 0.39). This is consistent with other evidence showing a steep population decline occurring in the mid to late 20th century in the NWA, whereas the SA population appears to have been relatively stable. Estimates of effective population size ranged from 22.6 to 66.3 (NWA) and 188 to 1998.3 (SA) and evidence of inbreeding was found (primarily in NWA). Overall, our findings indicate that white population dynamics within NWA and SA are determined more by intrinsic reproduction than immigration and there is genetic evidence of a population decline in the NWA, further justifying the strong domestic protective measures that have been taken for this species in this region. Our study also highlights how assessment of genetic diversity can complement other sources of information to better understand the status of threatened marine fish populations.

  16. Dictyoceratida (Porifera: Demospongiae) from Tropical Southwestern Atlantic (Northeastern Brazil, Sergipe State) and the description of three new species.

    PubMed

    Sandes, Joana; Pinheiro, Ulisses

    2014-07-21

    Five species of dictyoceratid sponges were collected from trawling on the continental shelf of Sergipe State, Northeastern Brazil, of which three are new to science: Ircinia sergipana sp. nov., Ircinia repens sp. nov., Ircinia strobilina, Hyattella cavernosa and Smenospongia ramosa sp. nov., the latter the first record of the genus Smenospongia from Brazil. 

  17. 76 FR 39369 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fishery; Amendment 3

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-06

    ... United States; Atlantic Deep-Sea Red Crab Fishery; Amendment 3 AGENCY: National Marine Fisheries Service... Crab Fishery Management Plan (Red Crab FMP). The New England Fishery Management Council (Council) developed Amendment 3 to bring the Red Crab FMP into compliance with the annual catch limit (ACL)...

  18. 76 FR 60379 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab; Amendment 3

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-29

    ... measures in Amendment 3 published in the Federal Register on July 6, 2011 (76 FR 39369), with public... Amendment 3 was published in the Federal Register on June 22, 2011 (76 FR 36511), with public comments... United States; Atlantic Deep-Sea Red Crab; Amendment 3 AGENCY: National Marine Fisheries Service...

  19. Measurements of the stable carbon isotope composition of dissolved inorganic carbon in the northeastern Atlantic and Nordic Seas during summer 2012

    NASA Astrophysics Data System (ADS)

    Humphreys, M. P.; Achterberg, E. P.; Griffiths, A. M.; McDonald, A.; Boyce, A. J.

    2015-06-01

    The stable carbon isotope composition of dissolved inorganic carbon (δ13CDIC) in seawater was measured in a batch process for 552 samples collected during two cruises in the northeastern Atlantic and Nordic Seas from June to August 2012. One cruise was part of the UK Ocean Acidification research programme, and the other was a repeat hydrographic transect of the Extended Ellett Line. In combination with measurements made of other variables on these and other cruises, these data can be used to constrain the anthropogenic component of dissolved inorganic carbon (DIC) in the interior ocean, and to help to determine the influence of biological carbon uptake on surface ocean carbonate chemistry. The measurements have been processed, quality-controlled and submitted to an in-preparation global compilation of seawater δ13CDIC data, and are available from the British Oceanographic Data Centre. The observed δ13CDIC values fall in a range from -0.58 to +2.37 ‰, relative to the Vienna Pee Dee Belemnite standard. The mean of the absolute differences between samples collected in duplicate in the same container type during both cruises and measured consecutively is 0.10 ‰, which corresponds to a 1σ uncertainty of 0.09 ‰, and which is within the range reported by other published studies of this kind. A crossover analysis was performed with nearby historical δ13CDIC data, indicating that any systematic offsets between our measurements and previously published results are negligible. Data doi:10.5285/09760a3a-c2b5-250b-e053-6c86abc037c0 (northeastern Atlantic), doi:10.5285/09511dd0-51db-0e21-e053-6c86abc09b95 (Nordic Seas).

  20. Seroprevalence of Toxoplasma gondii in North-eastern Atlantic harbor seal (Phoca vitulina vitulina) and grey seal (Halichoerus grypus).

    PubMed

    Cabezón, O; Hall, A J; Vincent, C; Pabón, M; García-Bocanegra, I; Dubey, J P; Almería, S

    2011-06-30

    Antibodies to Toxoplasma gondii were determined in serum samples from 47 grey seals (Halichoerus grypus) and 56 harbor seals (Phoca vitulina vitulina) from the Atlantic coasts of United Kingdom and France. Antibodies to T. gondii assayed by the modified agglutination test (MAT) were found in 14 (13.6%; IC(95%): 7.0-20.2) of 103 seals tested, with titres of 1:25 in 13 seals and 1:50 in 1 seal. Seroprevalence against T. gondii (MAT 1:25 or higher) was significantly higher in grey seals (23.4%) compared to harbor seals (5.4%). No significant differences were found between seroprevalence against T. gondii and sex, age or geographical locations. These results show natural exposure of European harbor and grey seals to T. gondii oocysts in the Atlantic Ocean. To the best of our knowledge, this is the first serological survey of T. gondii in European grey and harbor seals.

  1. New dense-grid aeromagnetic map of Gulf of Guinea cul-de-sac, northeastern equatorial Atlantic Ocean

    SciTech Connect

    Babalola, O.O.

    1985-02-01

    As part of a major project to procure miscellaneous geophysical coverage of the entire country, the Geological Survey of Nigeria has acquired aeromagnetic data, presented as contour maps at various scales, over the nation's 7 sedimentary basins. The coverage over the Nigerian continental margin, acquired at 2500 ft above sea level, was flown at 4-km flight-line spacing in a north-northeasterly direction and at 20-km tie-line spacing in a west-northwesterly direction. Another tie line was flown along the coastline. Twenty 1:250,000 one-degree square, total intensity aeromagnetic contour maps covering the marginal basins down to the shelf break were assembled into a single aeromagnetic map of the Gulf of Guinea cul-desac. The map area lies within lat. 3/sup 0/-8/sup 0/N, and long. 2/sup 0/-9/sup 0/E. It covers the Nigerian portion of the Dahomey embayment, the Anambra and Niger delta basins, and the southern portion of the Benue rift. The map covers the location of the postulated Late Cretaceous triple junction involving the Benue Trough aulacogen, the northward-propagating South Atlantic, and the transform-dominated Equatorial Atlantic. In addition to the region seaward of the continental shelf, the map covers the Niger Delta basin, the basement of which is also inferred to consist mainly of oceanic crust prograded by the thick sediments of the Tertiary Niger delta. This areas is also the location of the Late Cretaceous coalescence of the North Atlantic and South Atlantic spreading systems hitherto separate from one another. This new aeromagnetic map fills an important data gap (due to proprietary restrictions and acquisition difficulties) in previous studies of this oil-prolific and geologically unique province. The map would be useful in future structural and tectonics studies of the Gulf of Guinea cul-de-sac.

  2. Source and Delivery of Nutrients to Receiving Waters in the Northeastern and Mid-Atlantic Regions of the United States1

    PubMed Central

    Moore, Richard B; Johnston, Craig M; Smith, Richard A; Milstead, Bryan

    2011-01-01

    Abstract This study investigates nutrient sources and transport to receiving waters, in order to provide spatially detailed information to aid water-resources managers concerned with eutrophication and nutrient management strategies. SPAtially Referenced Regressions On Watershed attributes (SPARROW) nutrient models were developed for the Northeastern and Mid-Atlantic (NE US) regions of the United States to represent source conditions for the year 2002. The model developed to examine the source and delivery of nitrogen to the estuaries of nine large rivers along the NE US Seaboard indicated that agricultural sources contribute the largest percentage (37%) of the total nitrogen load delivered to the estuaries. Point sources account for 28% while atmospheric deposition accounts for 20%. A second SPARROW model was used to examine the sources and delivery of phosphorus to lakes and reservoirs throughout the NE US. The greatest attenuation of phosphorus occurred in lakes that were large relative to the size of their watershed. Model results show that, within the NE US, aquatic decay of nutrients is quite limited on an annual basis and that we especially cannot rely on natural attenuation to remove nutrients within the larger rivers nor within lakes with large watersheds relative to the size of the lake. PMID:22457578

  3. Intracultural Variation in the Knowledge of Medicinal Plants in an Urban-Rural Community in the Atlantic Forest from Northeastern Brazil

    PubMed Central

    de Almeida, Cecília de Fátima Castelo Branco Rangel; Ramos, Marcelo Alves; Silva, Rafael Ricardo Vasconcelos; de Melo, Joabe Gomes; Medeiros, Maria Franco Trindade; Araújo, Thiago Antonio de Sousa; de Almeida, Alyson Luiz Santos; de Amorim, Elba Lúcia Cavalcanti; Alves, Rômulo Romeu da Nóbrega; de Albuquerque, Ulysses Paulino

    2012-01-01

    This study assessed the intracultural knowledge of the use of medicinal plants in an urban-rural community in an Atlantic forest fragment in northeastern Brazil. We examined the importance of native and exotic species and the effects of gender and age on that knowledge. We also compared data obtained from different groups of informants (local experts and general community). We conducted 194 interviews between June 2007 and January 2008, using the freelist technique and semistructured forms to collect ethnobotanical data. Information obtained from the community was compared with that from six local experts who participated in a survey in 2003. From a total of 209 ethnospecies, exotic and herbaceous plants presented higher richness. With respect to the number of citations, women and older informants were shown to know a higher number of medicinal plants. Comparing knowledge of local experts with that of the general community, we noted that experts know a similar wealth of plant families and therapeutic indications, but the community knows a greater species richness. These results indicate that local experts may provide useful information for studies that search for a quick diagnosis of the knowledge of a given community. PMID:22110546

  4. Reactive mercury in the troposphere: Model formation and results for Florida, the northeastern United States, and the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Sillman, Sanford; Marsik, Frank J.; Al-Wali, Khalid I.; Keeler, Gerald J.; Landis, Matthew S.

    2007-12-01

    We describe the development of a model for transport and photochemistry of atmospheric mercury at the regional scale, along with an application to the eastern United States and adjacent Atlantic Ocean and Gulf of Mexico, and comparison with aircraft-based measurements in Florida. The model is the Community Multiscale Air Quality model (CMAQ) with modifications to include an integrated solution for gas phase and aqueous photochemistry. The expanded chemistry includes O3, NOx, organics, sulfur, halogens and mercury. Divalent reactive gaseous mercury (RGM) is formed slowly through gas phase reactions and removed rapidly by aqueous reactions in cloud water. Model results show that elevated RGM (up to 260 pg m-3) forms intermittently over the Atlantic Ocean in air masses that have a cloud-free history. Aircraft measurements in Florida show RGM varying between 10 and 250 pg m-3 and increasing with altitude, a pattern that is consistent with model results. Ambient RGM would increase by 50% if aqueous reduction reactions were omitted. The model predicts that ambient elemental mercury and RGM anticorrelate in regions where RGM is produced photochemically and correlate in regions dominated by direct emissions. Model results also suggest positive correlations between RGM and SO2, reactive nitrogen and H2O2, which may be used to identify photochemically produced versus directly emitted RGM. RGM in the model is strongly correlated with O3 during pollution events, and ozone formation from anthropogenic precursors is predicted to cause a significant increase in RGM.

  5. Discriminating dusts and dusts sources using magnetic properties and hematite:Goethite ratios of surface materials and dust from North Africa, the Atlantic and Barbados

    NASA Astrophysics Data System (ADS)

    Oldfield, F.; Chiverrell, R. C.; Lyons, R.; Williams, E.; Shen, Z.; Bristow, C.; Bloemendal, J.; Torrent, J.; Boyle, J. F.

    2014-06-01

    Magnetic measurements and Diffuse Reflectance Spectroscopy are used in an attempt to differentiate dusts and dust sources in North Africa, over the Atlantic and in Barbados. Special attention is paid to dusts and to lacustrine clay and diatomite samples from the Bodélé Depression, in view of its alleged importance in trans-Atlantic and global dust generation. The results indicate that dusts from the Bodélé Depression can be distinguished from other dusts and potential sources in Niger, Chad, Burkina and Mali on the basis of their magnetic properties, notably their low magnetic concentrations, negligible frequency dependent magnetic susceptibility and distinctive IRM demagnetization characteristics. Dust from over the Atlantic and from Barbados, obtained from meshes in the 1960s and ’70s have high frequency dependent susceptibility values, are quite distinctive from the Bodélé Depression samples and are more closely comparable to samples from elsewhere in the Sahara and especially the Sahel. The Diffuse Reflectance Spectroscopy data, though of limited value here, are not inconsistent with the inferences based on the magnetic measurements. Overall, the results obtained point to a wide range of sources for dusts both over North Africa itself and across the Atlantic. They do not offer support to the view that dusts from the Bodélé Depression have dominated supply across the Atlantic over the last five decades.

  6. Africa.

    ERIC Educational Resources Information Center

    Martz, Carlton

    2001-01-01

    This publication explores issues related to Africa. It examines the U.S. response to the Barbary pirate states (Morocco, Algiers, Tunis, Tripoli) in the early 19th century; the current AIDS crisis in Africa; and 14th century Mali and other Islamic lands through the eyes of Ibn Battuta, who traveled throughout the Muslim world. Each article…

  7. Africa.

    ERIC Educational Resources Information Center

    Happel, Sue; Loeb, Joyce

    Although the activities in this unit are designed primarily for students in the intermediate grades, the document's text, illustrations, and bibliographic references are suitable for anyone interested in learning about Africa. Following a brief introduction and map work, the document is arranged into six sections. Section 1 traces Africa's history…

  8. Upper Intermediate Water Reservoir Ages in the Northeastern Atlantic During the Past 11000 Years: New Evidence for Mid Holocene Freshening of the North Atlantic

    NASA Astrophysics Data System (ADS)

    Frank, N.; Paterne, M.; Blamart, D.; Colin, C.; Tisnerat-Laborde, N.; van Weering, T.; Henriet, J.

    2006-12-01

    Deep-water corals such as Lophelia pertusa and Madrepora occulata construct reef like structures along the slopes of Rockall Trough and within the Porcupine Seabight between 500 and 1000m depth, so called carbonate mounds. The hydrography is complex, with upper intermediate and surface water originating in the temperate North Atlantic and water masses from the sub-polar gyre and Labrador Sea circulating at depth within the Rockall Trough. Moreover, Norwegian Sea deep-water returns southward over the sill close to Rosemary Bank and move along the western slope of Rockall Bank. In addition, strong winter mixing of up to 1000m depth causes a significant contribution of surface water at depth and vise versa. Sediment coring on carbonate mounds and subsequent U series dating of coral skeletons has revealed up to 5m thick Holocene coral reef structures. Combined U series and 14C dating on those corals allows reconstructing upper intermediate water reservoir ages almost continuously for the entire Holocene. Here we present a compilation of 40 reservoir ages from western Rockall Bank and Porcupine Seabight that span from 400 years PB to ~11000 years BP representing water masses between 610 and 750m depth. Reservoir ages vary remarkably between as low as 150 years to up to 800 years throughout the Holocene. Variable reservoir ages are recorded at the beginning of the Holocene having mean values of about 450-500 years. The Mid-Holocene warm phase between 8500 and 6000 years BP revealed stunningly small and constant reservoir ages of about 200±150 years indicating extremely well ventilated upper intermediate waters. Than reservoir ages rise towards values as high as 700 years and drop down again to about 500 years at 4000 years BP. During the past 4000 years reservoir ages remain far more stable at 450- 500 years. Such changes in upper intermediate water ventilation agree with changes in Northern Hemisphere climate and oceanography recorded by other sedimentary proxies such

  9. 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

  10. Family-level AMBI is valid for use in the north-eastern Atlantic but not for assessing the health of microtidal Australian estuaries

    NASA Astrophysics Data System (ADS)

    Tweedley, James R.; Warwick, Richard M.; Clarke, K. Robert; Potter, Ian C.

    2014-03-01

    Analysis of benthic macroinvertebrate samples at a higher taxonomic level than species, e.g. family, potentially provides a more cost-effective protocol for environmental impact assessments and monitoring as it requires less time, funds and taxonomic expertise. Using the AMBI database, species ecological group scores are shown to be coherent within families. Faunal data from a wide range of environmental impact scenarios in the north-eastern Atlantic demonstrate that AMBI, calculated from mean values for families, exhibits a strong linear relationship with species-level AMBI, the correlation improving by using square-root transformed rather than untransformed abundances. In many regions of the world, however, the sensitivity of benthic macroinvertebrates to environmental perturbations is unknown, precluding the use of AMBI for environmental assessments. Yet the families are essentially the same as in the AMBI database. The utility of family-level AMBI is tested using data for four south-western Australian estuaries previously subjected to environmental quality assessments, but where only 17 species of the 144 taxa are included in the AMBI database. Although family-level AMBI scores reflect differences in environmental quality spatially and temporally within an estuary, they do not follow variations in environmental quality among estuaries. Indeed, south-western Australia estuaries are numerically dominated by families with high AMBI scores, probably due to the detrimental effects of natural accumulations of organic material in estuaries with long residence times. As taxonomic distinctness follows trends in environmental quality among estuaries, as well as temporally and spatially within a system, it provides an appropriate substitute for assessing the 'heath' of microtidal estuaries.

  11. Radiative Effects and Feedbacks of Saharan Dust and Biomass Burning Aerosol over West Africa and the Northern Tropical Atlantic

    NASA Astrophysics Data System (ADS)

    Heinold, Bernd; Tegen, Ina; Bauer, Stefan; Wendisch, Manfred

    2010-05-01

    Soil dust aerosol from the world's arid and semi-arid regions and land fire smoke represent major components of the atmospheric aerosol load. They influence the climate system by changing the atmospheric radiation balance through direct and indirect effects and play an important role in the biogeochemical and hydrological cycle. However, in particular the magnitude and sign of the radiative effects are highly uncertain due to still existing uncertainties in their optical properties and the variability and complexity of the spatio-temporal distribution. The dust and biomass burning aerosol from Africa is of particular interest since the continent harbours the largest and most active sources of both aerosol types. The Saharan and Sahel regions contribute at least 50% to the global dust emissions and a considerable amount of smoke originates from active biomass burning areas in west and central Africa. Within continuous aerosol outbreaks, the Saharan dust and land fire smoke are transported towards the West African Monsoon region and across the tropical Atlantic Ocean. In boreal winter, when the most land fires are active, the Saharan dust layer merges with the West African smoke plumes resulting in a complex aerosol layering. Here, the results of a regional model study on direct radiative forcing and dynamic atmospheric response due to dust and biomass burning aerosol will be presented. Particular focus will be on radiative impacts on regional circulation patterns and implications for the aerosol transport. For simulations of the complex spatial distribution of the West African aerosol and estimates of direct radiative effects and feedbacks, the regional model system COSMO-MUSCAT is used. The model allows online interaction of the computed dust and biomass burning aerosol load with the solar and thermal radiation and with the model dynamics. The simulations are performed for the second field campaign of the SAharan Mineral dUst experiMent (SAMUM) that was conducted

  12. Recent invasion of the tropical Atlantic by an Indo-Pacific coral reef fish.

    PubMed

    Rocha, Luiz A; Robertson, D Ross; Rocha, Claudia R; Van Tassell, James L; Craig, Matthew T; Bowen, Brian W

    2005-11-01

    The last tropical connection between Atlantic and Indian-Pacific habitats closed c. 2 million years ago (Ma), with the onset of cold-water upwelling off southwestern Africa. Yet comparative morphology indicates more recent connections in several taxa, including reef-associated gobies (genus Gnatholepis). Coalescence and phylogenetic analyses of mtDNA cytochrome b sequences demonstrate that Gnatholepis invaded the Atlantic during an interglacial period approximately 145,000 years ago (d = 0.0054), colonizing from the Indian Ocean to the western Atlantic, and subsequently to the central ( approximately 100,000 years ago) and eastern Atlantic ( approximately 30,000 years ago). Census data show a contemporary range expansion in the northeastern Atlantic linked to global warming.

  13. Predicting Atlantic seasonal hurricane activity using outgoing longwave radiation over Africa

    NASA Astrophysics Data System (ADS)

    Karnauskas, Kristopher B.; Li, Laifang

    2016-07-01

    Seasonal hurricane activity is a function of the amount of initial disturbances (e.g., easterly waves) and the background environment in which they develop into tropical storms (i.e., the main development region). Focusing on the former, a set of indices based solely upon the meridional structure of satellite-derived outgoing longwave radiation (OLR) over the African continent are shown to be capable of predicting Atlantic seasonal hurricane activity with very high rates of success. Predictions of named storms based on the July OLR field and trained only on the time period prior to the year being predicted yield a success rate of 87%, compared to the success rate of NOAA's August outlooks of 53% over the same period and with the same average uncertainty range (±2). The resulting OLR indices are statistically robust, highly detectable, physically linked to the predictand, and may account for longer-term observed trends.

  14. Detachment and steep normal faulting in Atlantic oceanic crust west of Africa

    USGS Publications Warehouse

    Reston, T.J.; Ruoff, O.; McBride, J.H.; Ranero, C.R.; White, Robert S.

    1996-01-01

    Improved images of the internal structure of Early Cretaceous North Atlantic crust reveal both probable detachment faults and more steeply dipping normal faults. The detachment faults occur as subhorizontal structures passing ???1.5 km beneath fault blocks without offset; several steeper block-bounding faults appear to detach onto these structures. However, the detachments are bounded to the west (ridgeward) by presumably younger, more steeply west-dipping normal faults. In one possible interpretation, the detachment and the steep faults belong to the same "rolling-hinge" extension system. An intriguing alternative is that a phase of detachment faulting, perhaps related to increased magmatic activity, was succeeded by localized amagmatic extension along steeper and more deeply penetrating faults.

  15. A model study of the seasonality of sea surface temperature and circulation in the Atlantic North-Eastern Tropical Upwelling System.

    NASA Astrophysics Data System (ADS)

    Faye, Saliou; Lazar, Alban; Sow, Bamol; Gaye, Amadou

    2015-09-01

    The climatological seasonal cycle of the sea surface temperature (SST) in the north-eastern tropical Atlantic (7-25°N, 26-12°W) is studied using a mixed layer heat budget in a regional ocean general circulation model. The region, which experiences one of the larger SST cycle in the tropics, forms the main part of the Guinea Gyre. It is characterized by a seasonally varying open ocean and coastal upwelling system, driven by the movements of the intertropical convergence zone (ITCZ). The model annual mean heat budget has two regimes schematically. South of roughly 12°N, advection of equatorial waters, mostly warm, and warming by vertical mixing, is balanced by net air-sea flux. In the rest of the domain, a cooling by vertical mixing, reinforced by advection at the coast, is balanced by the air-sea fluxes. Regarding the seasonal cycle, within a narrow continental band, in zonal mean, the SST early decrease (from September, depending on latitude, until December) is driven by upwelling dynamics off Senegal and Mauritania (15°-20°N), and instead by air-sea fluxes north and south of these latitudes. Paradoxically, the later peaks of upwelling intensity (from March to July, with increasing latitude) essentially damp the warming phase, driven by air-sea fluxes. The open ocean cycle to the west, is entirely driven by the seasonal net air-sea fluxes. The oceanic processes significantly oppose it, but for winter north of ~18°N. Vertical mixing in summer-autumn tends to cool (warm) the surface north (south) of the ITCZ, and advective cooling or warming by the geostrophic Guinea Gyre currents and the Ekman drift. This analysis supports previous findings on the importance of air-sea fluxes offshore. It mainly offers quantitative elements on the modulation of the SST seasonal cycle by the ocean circulation, and particularly by the upwelling dynamics. Keywords: SST, upwelling, circulation, heat budget, observations, modeling

  16. Africa.

    ERIC Educational Resources Information Center

    Crofts, Marylee

    1986-01-01

    Reviews myths, misconceptions, and unintentional biases about Africa in United States K-12 social studies textbooks. Summarizes common topics and recommends additions. Provides the names, addresses and phone numbers of 10 university-based African Studies centers. Concludes that improvements to textbooks must continue. (JDH)

  17. Chryseobacterium piscium sp. nov., isolated from fish of the South Atlantic Ocean off South Africa.

    PubMed

    de Beer, Hanli; Hugo, Celia J; Jooste, Piet J; Vancanneyt, Marc; Coenye, Tom; Vandamme, Peter

    2006-06-01

    Four isolates from freshly caught fish samples obtained from the South Atlantic Ocean off the South African coastline were shown to represent a novel species in the genus Chryseobacterium by means of a polyphasic taxonomic study. The four isolates had virtually identical whole-cell protein profiles, fatty acid profiles and biochemical properties. Analysis of the 16S rRNA sequence of strain LMG 23089(T) revealed 99.3 and 98.9 % similarity to the 16S rRNA sequences of the type strains of Chryseobacterium balustinum and Chryseobacterium scophthalmum, respectively. Strain LMG 23089(T) and the C. balustinum and C. scophthalmum type strains formed a stable lineage supported by a bootstrap value of 100 %. The levels of DNA-DNA hybridization towards these nearest phylogenetic neighbours were below 57 %. The absence of growth on MacConkey agar or at 37 degrees C (on nutrient agar), the capacity to grow in the presence of 5 % NaCl and the production of urease activity differentiate this novel taxon from C. balustinum and C. scophthalmum. The four isolates are formally classified as Chryseobacterium piscium sp. nov., with strain LMG 23089(T) (=CCUG 51923(T)) as the type strain. Its DNA G + C content is 33.6 mol%. PMID:16738109

  18. First report of geophilid centipedes of the genus Ribautia (Myriapoda: Chilopoda: Geophilomorpha) from the Atlantic Forest biome, with description of a new miniature species from Misiones Province, Northeastern Argentina.

    PubMed

    Pereira, Luis Alberto

    2014-01-01

    Ribautia paranaensis sp. nov. a new miniature species of geophilid centipede from the Upper Paraná Atlantic Forest (the westernmost of the fifteen ecoregions comprising the Atlantic Forest biome sensu Di Bitetti et al. 2003), is herein described and illustrated. The new species is characterized by having the coxal organs grouped in clusters (one of these in each coxopleuron of the ultimate leg-bearing segment) and a claw-like pretarsus in the ultimate legs; these traits being shared by three other Neotropical members of the genus, i.e., R. combinata Pereira, Uliana & Minelli, 2006 (from the Amazonian rainforest of Peru), R. jakulicai Pereira, 2007 (from the Yungas rainforest of Northwestern Argentina), and R. lewisi Pereira, 2013 (collected in a gallery forest in the Mesopotamian region, Northeastern Argentina). R. paranaensis sp. nov. represents the first report of Ribautia Brölemann, 1909 in the entire Atlantic Forest biome, and the third confirmed record of the taxon from Argentina. PMID:24871738

  19. Northeastern Summer Electricity Market Alert

    EIA Publications

    2013-01-01

    The National Weather Service declared an excessive-heat warning for much of the Mid-Atlantic and northeastern United States, including major electric markets covering Philadelphia, Boston, Washington, D.C., and New York City. This report highlights the wholesale electricity market activity occurring in response to the higher-than-normal electricity demand caused by the heat wave.

  20. Understanding the life of a sandy beach polychaete of functional importance - Scolelepis squamata (Polychaeta: Spionidae) on Belgian sandy beaches (northeastern Atlantic, North Sea)

    NASA Astrophysics Data System (ADS)

    Speybroeck, Jeroen; Alsteens, Lotte; Vincx, Magda; Degraer, Steven

    2007-08-01

    The cosmopolitan sandy beach polychaete Scolelepis squamata constitutes an important food resource for juvenile flatfish and wading birds in the northeastern Atlantic, thus playing an important role in sandy beach ecosystem functioning. However, its population dynamics and life history in this part of the world have gone widely uninvestigated. Eight beach transects on Belgian sandy beaches were sampled monthly from October 2003 until October 2004, in order to investigate seasonal trends in the species' abundance, biomass, secondary production, and patterns in reproduction and zonation. Average density, modal density and modal biomass (ash-free dry weight) (mean average density = 169 ± 9 SE ind/m 2; mean modal density = 505 ± 38 SE ind/m 2; mean modal biomass = 0.25 ± 0.02 SE g/m 2) did not exhibit major seasonal changes, whereas average biomass (0.081 ± 0.005 SE g/m 2) and individuals and biomass per strip transect (IST = 16286 ± 1330 SE ind/m; BMST = 7.8 + 0.7 SE g/m) did, peaking in May 2004. Production was calculated at 1.9 g/(m 2*year) (size-frequency method, SFM) and 0.88 g/(m 2*year) (mass specific growth rate method, MSGR) and mean annual biomass was 0.797 g/m 2; resulting in a P/B ratio of 2.40/year (SFM) and 1.11/year (MSGR), which is intermediate to moderately low compared to other polychaete species. Gravid individuals were found from February until August and a single recruitment period was observed from July until September. An average sex ratio of 1.41 ± 0.08 SE was calculated, with a female predominance. Highest densities (>200 ind/m 2) were mostly found above 3 m above MLLWS and at a median grain size from 190 to 320 μm. Average modal or peak density along each transect was situated from 3.95 m up to 4.40 m above MLLWS, in contrast to some other studies where the species was restricted to mid-tidal levels. Significant differences in elevation of peak density were found between non-gravid (411 ± 4 SE cm) and gravid (402 ± 5 SE cm) animals

  1. Biodiversity patterns of the marine benthic fauna on the Atlantic coast of tropical Africa in relation to hydroclimatic conditions and paleogeographic events

    NASA Astrophysics Data System (ADS)

    Lœuff, Pierre Le; von Cosel, Rudo

    1998-06-01

    Five different hydroclimatic regions are recognized in the tropical eastern Atlantic: the northern alternance region (Cape Blanc - Cape Verga), the atypical tropical region (Cape Palmas - border Benin/Nigeria), the southern alternance region (Cape Lopez - Cape Frio), all with periodical upwelling of colder water, and two intercalated typical tropical regions with warm water and reduced salinity. The faunal richness in the regions with upwelling is higher than in the typical tropical regions because many benthic species avoid warm and reduced salinity water. Faunistic exchange and affinity are greater between the upwelling zones and the bordering temperate zones. The cold regions are also more similar in faunal composition. Benthic communities in both tropical and temperate eastern Atlantic are not fundamentally different. Species diversity of benthic invertebrates in tropical West Africa is about the same order of magnitude as in Europe and the Mediterranean. Hydroclimatic conditions (upwelling, salinity reduction and internal waves with drastic temperature changes) and absence of coral reef formations do not favour the establishment and thriving of a warm stenohaline and stenotherm fauna in West Africa. Paleozoogeographic events, such as the formation of a large Euro-West African tropical province during the Miocene after the breakup of the Tethys, repeated climate deteriorations during Pliocene and Pleistocene with reductions of the tropical zone, sea level changes and large-scale extinction of warm-tropical species, are also factors responsible for the current low biodiversity in the tropical eastern Atlantic. Some species survived in two major relict pockets in Senegal and southern Angola with particular ecological conditions.

  2. Length composition and abundance of eel larvae, Anguilla anguilla (anguilliformes: Anguillidae), in the iberian basin (northeastern Atlantic) during July September 1984

    NASA Astrophysics Data System (ADS)

    Bast, H.-D.; Strehlow, B.

    1990-09-01

    376 leptocephali of Anguilla anguilla (L., 1758) from the Iberian Basin were analysed. The observed horizontal trends of abundance and particularly the mean sizes contradict the expectations based on the hypothesis of larvae distribution exclusively by drift with Gulf and North Atlantic Currents, and support the hypothesis of an active larval migration also south of the Azores.

  3. 78 FR 61838 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Removal of 2,000-lb (907.2...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-04

    ... National Oceanic and Atmospheric Administration 50 CFR Part 648 RIN 0648-XC894 Fisheries of the... Atlantic Herring Management Area 2 AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION: Temporary rule. SUMMARY: NMFS announces a...

  4. A new 200 Ma paleomagnetic pole for Africa, and paleo-secular variation scatter from Central Atlantic Magmatic Province (CAMP) intrusives in Morocco (Ighrem and Foum Zguid dykes)

    NASA Astrophysics Data System (ADS)

    Palencia-Ortas, A.; Ruiz-Martínez, V. C.; Villalaín, J. J.; Osete, M. L.; Vegas, R.; Touil, A.; Hafid, A.; McIntosh, G.; van Hinsbergen, D. J. J.; Torsvik, T. H.

    2011-06-01

    Available apparent polar wander (APW) paths for the 200 Ma configuration of Pangea, just prior to the opening of the Central Atlantic Ocean, differ as much as 10o in arc length. Here, we add new data from northwest Africa for this time, obtained from the northeast-trending Foum-Zguid and Ighrem dykes (ca. 200 Ma). These dykes form part of the northern domain of the Central Atlantic Magmatic Province (CAMP), and crosscut the Anti-Atlas Ranges in Morocco, and compositionally correspond to quartz-normative tholeiites intruded in continental lithosphere shortly before the opening of the Central Atlantic Ocean. The Foum-Zguid dyke has been intensively studied, whereas the Ighrem dyke has received less scientific focus. We sampled both dykes for paleomagnetic investigation along 100 km of each dyke (12 sites for Foum-Zguid and 11 for Ighrem, 188 samples included in the final analyses). Rock magnetic experiments indicate a mixture of multidomain and single-domain magnetite and/or low-Ti titanomagnetite particles as the principal remanence carriers. In both dykes, the primary nature of the characteristic remanent magnetization is supported by positive contact tests, related to Fe-metasomatism or baked overprints of the corresponding sedimentary country rocks. The directions of the characteristic magnetization exhibit exclusively normal polarity. Site-mean virtual geomagnetic poles are differently grouped in each dyke, suggesting distinct geomagnetic secular variation records. The Foum-Zguid paleomagnetic pole (N= 12, PLat= 67.9°N, PLon= 247.9°E, κ= 125, A95= 3.9°) plots close to that of Ighrem (N= 11, PLat= 78.4°N, PLon= 238.2°E, κ= 47, A95= 6.7°), confirming those mineralogical and geochemical evidences supporting that they represent dissimilar magmatic stages. Virtual geomagnetic poles dispersion from both dykes (S= 10.5°13.0°8.1°) is in line with those obtained from recent studies of a CAMP-related dyke in Iberia and results from CAMP lavas in the Argana

  5. Knowledge and use of medicinal plants by local specialists in an region of Atlantic Forest in the state of Pernambuco (Northeastern Brazil)

    PubMed Central

    Gazzaneo, Luiz Rodrigo Saldanha; de Lucena, Reinaldo Farias Paiva; de Albuquerque, Ulysses Paulino

    2005-01-01

    The study of local knowledge about natural resources is becoming increasingly important in defining strategies and actions for conservation or recuperation of residual forests. This study therefore sought to: collect information from local populations concerning the use of Atlantic Forest medicinal plants; verify the sources of medicinal plants used; determine the relative importance of the species surveyed, and; calculate the informant consensus factor in relation to medicinal plant use. Data was obtained using semi-structured forms to record the interviewee's personal information and topics related to the medicinal use of specific plants. The material collected represent 125 plants, distributed among 61 botanical families, with little participation of native plants. This study demonstrated that local people tend to agree with each other in terms of the plants used to treat blood-related problems, but cite a much more diverse group of plants to treat problems related to the respiratory and digestive systems – two important categories in studies undertaken in different parts of the world. The local medicinal flora is largely based on plants that are either cultivated or obtained from anthropogenic zones, possibly due to the use and access restrictions of the legally protected neighboring forest. Despite these restrictions, the species with the highest use-value by this community was Pithecellobium cochliocarpum (Gomez) Macb., a native plant of the Atlantic Forest. PMID:16270911

  6. At the Crossroads: Hazard Assessment and Reduction of Health Risks from Arsenic in Private Well Waters of Northeastern United States and Atlantic Canada

    PubMed Central

    Zheng, Yan; Ayotte, Joseph D.

    2014-01-01

    This special issue contains 12 papers that report on new understanding of arsenic hydrogeochemistry, performance of household well water treatment systems, and testing and treatment behaviors of well users in several states of the northeastern region of the United States and Nova Scotia, Canada. The responsibility to ensure water safety of private wells falls on well owners. In the U.S., 43 million Americans, mostly from rural areas, use private wells. In order to reduce As exposure in rural populations that rely on private wells for drinking water, risk assessment, which includes estimation of population at risk of exposure to As above the EPA Maximum Contaminant Level, is helpful but insufficient because it does not identify individual households at risk. Persistent optimism bias among well owners against testing and barriers such as cost of treatment mean that a large percentage of the population will not act to reduce their exposure to harmful substances such as As. If households are in areas with known As occurrence, a potentially large percentage of well owners will remain unaware of their exposure. To ensure that everyone, including vulnerable populations such as low income families with children and pregnant women, is not exposed to arsenic in their drinking water, alternative action will be required and warrants further research. PMID:25466685

  7. At the crossroads: Hazard assessment and reduction of health risks from arsenic in private well waters of the northeastern United States and Atlantic Canada

    USGS Publications Warehouse

    Zheng, Yan; Ayotte, Joseph

    2015-01-01

    This special issue contains 12 papers that report on new understanding of arsenic (As) hydrogeochemistry, performance of household well water treatment systems, and testing and treatment behaviors of well users in several states of the northeastern region of the United States and Nova Scotia, Canada. The responsibility to ensure water safety of private wells falls on well owners. In the U.S., 43 million Americans, mostly from rural areas, use private wells. In order to reduce As exposure in rural populations that rely on private wells for drinking water, risk assessment, which includes estimation of population at risk of exposure to As above the EPA Maximum Contaminant Level, is helpful but insufficient because it does not identify individual households at risk. Persistent optimistic bias among well owners against testing and barriers such as cost of treatment mean that a large percentage of the population will not act to reduce their exposure to harmful substances such as As. If households are in areas with known As occurrence, a potentially large percentage of well owners will remain unaware of their exposure. To ensure that everyone, including vulnerable populations such as low income families with children and pregnant women, is not exposed to arsenic in their drinking water, alternative action will be required and warrants further research.

  8. At the crossroads: Hazard assessment and reduction of health risks from arsenic in private well waters of the northeastern United States and Atlantic Canada.

    PubMed

    Zheng, Yan; Ayotte, Joseph D

    2015-02-01

    This special issue contains 12 papers that report on new understanding of arsenic (As) hydrogeochemistry, performance of household well water treatment systems, and testing and treatment behaviors of well users in several states of the northeastern region of the United States and Nova Scotia, Canada. The responsibility to ensure water safety of private wells falls on well owners. In the U.S., 43 million Americans, mostly from rural areas, use private wells. In order to reduce As exposure in rural populations that rely on private wells for drinking water, risk assessment, which includes estimation of population at risk of exposure to As above the EPA Maximum Contaminant Level, is helpful but insufficient because it does not identify individual households at risk. Persistent optimistic bias among well owners against testing and barriers such as cost of treatment mean that a large percentage of the population will not act to reduce their exposure to harmful substances such as As. If households are in areas with known As occurrence, a potentially large percentage of well owners will remain unaware of their exposure. To ensure that everyone, including vulnerable populations such as low income families with children and pregnant women, is not exposed to arsenic in their drinking water, alternative action will be required and warrants further research.

  9. New species of the genus Elachisina (Gastropoda: Elachisinidae) from northeastern Brazil.

    PubMed

    Cunha, Carlo M; Santos, Franklin N; Lima, Silvio F B

    2016-01-01

    The family Elachisinidae Ponder, 1985 includes minute marine gastropods that live predominantly in the sublittoral zone (Ponder & Keyzer 1998; Rolán & Rubio 2001; Rolán & Gofas 2003). Most elachisinids have been included in the genus Elachisina Dall, 1918 based on their shell morphology (Warén 1996; Rolán & Rubio 2001; Rolán & Gofas 2003), consequently, very little is known about the habitat and ecological niche of the species (Ponder & Keyzer 1998; Rolán & Gofas 2003). Elachisina floridana (Rehder, 1943) is the only Atlantic congener collected alive, and is known to live beneath rocks and in rocky crevices in the intertidal zone to about 1 m depth in the Bahamas and Caribbean Sea (Ponder 1985; Ponder & Keyzer 1998; Rolán & Gofas 2003; Redfern 2013). Eastern Atlantic E. canarica (Nordsieck & García-Talavera, 1979) was also collected alive from the Canary Islands, but with no information on the habitat (Rolán & Gofas 2003). The islands of the northeastern Atlantic and West Africa are the regions with the greatest Elachisina richness known, totaling nine species (Rolán & Rubio 2001; Rolán & Gofas 2003). Only E. floridana has been recognized so far to be widely distributed throughout the Western Atlantic (Rolán & Gofas 2003; Rios 2009; Redfern 2013). PMID:27470791

  10. 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...

  11. The ancient tropical rainforest tree Symphonia globulifera L. f. (Clusiaceae) was not restricted to postulated Pleistocene refugia in Atlantic Equatorial Africa

    PubMed Central

    Budde, K B; González-Martínez, S C; Hardy, O J; Heuertz, M

    2013-01-01

    Understanding the history of forests and their species' demographic responses to past disturbances is important for predicting impacts of future environmental changes. Tropical rainforests of the Guineo-Congolian region in Central Africa are believed to have survived the Pleistocene glacial periods in a few major refugia, essentially centred on mountainous regions close to the Atlantic Ocean. We tested this hypothesis by investigating the phylogeographic structure of a widespread, ancient rainforest tree species, Symphonia globulifera L. f. (Clusiaceae), using plastid DNA sequences (chloroplast DNA [cpDNA], psbA-trnH intergenic spacer) and nuclear microsatellites (simple sequence repeats, SSRs). SSRs identified four gene pools located in Benin, West Cameroon, South Cameroon and Gabon, and São Tomé. This structure was also apparent at cpDNA. Approximate Bayesian Computation detected recent bottlenecks approximately dated to the last glacial maximum in Benin, West Cameroon and São Tomé, and an older bottleneck in South Cameroon and Gabon, suggesting a genetic effect of Pleistocene cycles of forest contraction. CpDNA haplotype distribution indicated wide-ranging long-term persistence of S. globulifera both inside and outside of postulated forest refugia. Pollen flow was four times greater than that of seed in South Cameroon and Gabon, which probably enabled rapid population recovery after bottlenecks. Furthermore, our study suggested ecotypic differentiation—coastal or swamp vs terra firme—in S. globulifera. Comparison with other tree phylogeographic studies in Central Africa highlighted the relevance of species-specific responses to environmental change in forest trees. PMID:23572126

  12. Consequences of the Trans-Atlantic Slave Trade on Medicinal Plant Selection: Plant Use for Cultural Bound Syndromes Affecting Children in Suriname and Western Africa

    PubMed Central

    Vossen, Tessa; Towns, Alexandra; Ruysschaert, Sofie; Quiroz, Diana; van Andel, Tinde

    2014-01-01

    Folk perceptions of health and illness include cultural bound syndromes (CBS), ailments generally confined to certain cultural groups or geographic regions and often treated with medicinal plants. Our aim was to compare definitions and plant use for CBS regarding child health in the context of the largest migration in recent human history: the trans-Atlantic slave trade. We compared definitions of four CBS (walk early, evil eye, atita and fontanels) and associated plant use among three Afro-Surinamese populations and their African ancestor groups in Ghana, Bénin and Gabon. We expected plant use to be similar on species level, and assumed the majority to be weedy or domesticated species, as these occur on both continents and were probably recognized by enslaved Africans. Data were obtained by identifying plants mentioned during interviews with local women from the six different populations. To analyse differences and similarities in plant use we used Detrended Component Analysis (DCA) and a Wald Chi-square test. Definitions of the four cultural bound syndromes were roughly the same on both continents. In total, 324 plant species were used. There was little overlap between Suriname and Africa: 15 species were used on two continents, of which seven species were used for the same CBS. Correspondence on family level was much higher. Surinamese populations used significantly more weedy species than Africans, but equal percentages of domesticated plants. Our data indicate that Afro-Surinamers have searched for similar plants to treat their CBS as they remembered from Africa. In some cases, they have found the same species, but they had to reinvent the largest part of their herbal pharmacopeia to treat their CBS using known plant families or trying out new species. Ideas on health and illness appear to be more resilient than the use of plants to treat them. PMID:25372485

  13. Mitochondrial control region diversity of the houbara bustard Chlamydotis undulata complex and genetic structure along the Atlantic seaboard of North Africa.

    PubMed

    Idaghdour, Youssef; Broderick, Damien; Korrida, Amal; Chbel, Faiza

    2004-01-01

    The houbara bustard, Chlamydotis undulata, is a declining cryptic desert bird whose range extends from North Africa to Central Asia. Three subspecies are currently recognized by geographical distribution and morphology: C.u.fuertaventurae, C.u.undulata and C.u.macqueenii. We have sequenced 854 bp of mitochondrial control region from 73 birds to describe their population genetic structure with a particular sampling focus on the connectivity between C.u.fuertaventurae and C.u.undulata along the Atlantic seaboard of North Africa. Nucleotide and haplotypic diversity varied among the subspecies being highest in C.u.undulata, lowest in C.u.fuertaventurae and intermediate in C.u.macqueenii. C.u.fuertaventurae and C.u.undulata are paraphyletic and an average nucleotide divergence of 2.08% splits the later from C.u.macqueenii. We estimate that C.u.fuertaventurae and C.u.undulata split from C.u.macqueenii approximately 430 000 years ago. C.u.fuertaventurae and C.u.undulata are weakly differentiated (FST = 0.27, Nm = 1.3), indicative of a recent shared history. Archaeological evidence indicates that houbara bustards have been present on the Canary Islands for 130-170 000 years. However, our genetic data point to a more recent separation of C.u.fuertaventurae and C.u.undulata at around 20-25 000 years. Concordant archaeological, climatic opportunities for colonization and genetic data point to a scenario of: (i) initial colonization of the Canary Islands about 130 000 years ago; (ii) a period of secondary contact 19-30 000 years ago homogenizing any pre-existing genetic structure followed by; (iii) a period of relative isolation that persists today. PMID:14653787

  14. Mitochondrial control region diversity of the houbara bustard Chlamydotis undulata complex and genetic structure along the Atlantic seaboard of North Africa.

    PubMed

    Idaghdour, Youssef; Broderick, Damien; Korrida, Amal; Chbel, Faiza

    2004-01-01

    The houbara bustard, Chlamydotis undulata, is a declining cryptic desert bird whose range extends from North Africa to Central Asia. Three subspecies are currently recognized by geographical distribution and morphology: C.u.fuertaventurae, C.u.undulata and C.u.macqueenii. We have sequenced 854 bp of mitochondrial control region from 73 birds to describe their population genetic structure with a particular sampling focus on the connectivity between C.u.fuertaventurae and C.u.undulata along the Atlantic seaboard of North Africa. Nucleotide and haplotypic diversity varied among the subspecies being highest in C.u.undulata, lowest in C.u.fuertaventurae and intermediate in C.u.macqueenii. C.u.fuertaventurae and C.u.undulata are paraphyletic and an average nucleotide divergence of 2.08% splits the later from C.u.macqueenii. We estimate that C.u.fuertaventurae and C.u.undulata split from C.u.macqueenii approximately 430 000 years ago. C.u.fuertaventurae and C.u.undulata are weakly differentiated (FST = 0.27, Nm = 1.3), indicative of a recent shared history. Archaeological evidence indicates that houbara bustards have been present on the Canary Islands for 130-170 000 years. However, our genetic data point to a more recent separation of C.u.fuertaventurae and C.u.undulata at around 20-25 000 years. Concordant archaeological, climatic opportunities for colonization and genetic data point to a scenario of: (i) initial colonization of the Canary Islands about 130 000 years ago; (ii) a period of secondary contact 19-30 000 years ago homogenizing any pre-existing genetic structure followed by; (iii) a period of relative isolation that persists today.

  15. Assessment of carbon storage under rainforests in Humic Hapludox along a climosequence extending from the Atlantic coast to the highlands of northeastern Brazil.

    PubMed

    Araujo, Jane Kelly Silva; de Souza Júnior, Valdomiro Severino; Marques, Flávio Adriano; Voroney, Paul; da Silva Souza, Regilene Angelica

    2016-10-15

    An understanding of the stock of soil organic carbon (SOC) in the umbric epipedon of Oxisols located in the tropical forests surrounded by a semi-arid region is limited but essential because of their importance in the global cycle of carbon (C). The purpose of this study was to assess the effects of climatic (temperature and rainfall), soil organic matter (SOM) composition and litter on the stability of C in surfaces and subsurfaces in five Humic Oxisols along a 475-km climosequence from 143 to 963ma.s.l. in a tropical environment in northeastern Brazil. We assessed vertical changes in SOC; soil total nitrogen (N); C from the microbial biomass; δ(13)C, δ(15)N and the humified composition of SOM; the composition of the humin (HUM) fraction by Fourier Transform Infrared (FTIR); and Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC) at depth. The elemental and isotopic composition of the litter samples were analyzed in all areas studied. The results indicated that the current climate and recalcitrant organic compounds are not preponderant factors in the formation of the umbric epipedon, as suggested by the partial influence of temperature and rainfall on SOM. In addition, SOM was dominated by easily decomposable compounds, as indicated by the predominance of aliphatic C-H groups in the HUM fraction in the FTIR spectra; by the thermal oxidation through DSC-TG, which revealed that approximately 50% of the HUM was composed easily decomposable compounds; and by the high proportion of organic C present in the microbial biomass. Values of δ(13)C showed a predominance of C3 plant-C in SOM whereas δ(15)N patterns indicated that N dynamics differ among the profiles and drive the accumulation of C. These findings can help to characterize the susceptibility of these soils to changes in climate and land use and the implications for the sequestration of soil C. PMID:27300567

  16. Demography of a deep-sea lantern shark (Etmopterus spinax) caught in trawl fisheries of the northeastern Atlantic: Application of Leslie matrices with incorporated uncertainties

    NASA Astrophysics Data System (ADS)

    Coelho, Rui; Alpizar-Jara, Russell; Erzini, Karim

    2015-05-01

    The deep-sea lantern shark Etmopterus spinax occurs in the northeast Atlantic on or near the bottoms of the outer continental shelves and slopes, and is regularly captured as bycatch in deep-water commercial fisheries. Given the lack of knowledge on the impacts of fisheries on this species, a demographic analysis using age-based Leslie matrices was carried out. Given the uncertainties in the mortality estimates and in the available life history parameters, several different scenarios, some incorporating stochasticity in the life history parameters (using Monte Carlo simulation), were analyzed. If only natural mortality were considered, even after introducing uncertainties in all parameters, the estimated population growth rate (λ) suggested an increasing population. However, if fishing mortality from trawl fisheries is considered, the estimates of λ either indicated increasing or declining populations. In these latter cases, the uncertainties in the species reproductive cycle seemed to be particularly relevant, as a 2-year reproductive cycle indicated a stable population, while a longer (3-year cycle) indicated a declining population. The estimated matrix elasticities were in general higher for the survivorship parameters of the younger age classes and tended to decrease for the older ages. This highlights the susceptibility of this deep-sea squaloid to increasing fishing mortality, emphasizing that even though this is a small-sized species, it shows population dynamics patterns more typical of the larger-sized and in general more vulnerable species.

  17. The complex post-rift evolution of the South Atlantic margin, South Africa: new insights from joint inversion of apatite (U-Th)/He and fission track thermochronometry.

    NASA Astrophysics Data System (ADS)

    Wildman, Mark; Brown, Roderick; Persano, Cristina; Beucher, Romain; Stuart, Finlay

    2013-04-01

    The continental edge of southwestern Africa has long been seen as a type example of a high elevation passive margin, with its characteristic topography forming during or shortly after rifting (c. 130 Ma). Recent work along the South Atlantic passive margin has highlighted the importance of interactions between rift-tectonics, mantle flow and dynamic topography on controlling margin evolution, however, the temporal relationship between these processes is still poorly understood. There is now increasing evidence from satellite imagery, onshore field observations (e.g. Viola et al., 2012) and offshore sedimentary basin analysis (e.g. Hirsch et al., 2010) that suggests that these processes have resulted in a much more complex structural and thermal history along the margin than previously thought. A critical step towards developing a better understanding of the post-rift evolution of this margin is to quantify the surface response (i.e. uplift and erosion) to these major structural and thermal events. Apatite fission track analysis (AFTA) has been used world-wide as a powerful means of extracting quantitative constraints on the timing and rate of major episodes of onshore denudation. Previous AFTA studies in SW Africa have identified two distinct cooling events occurred during early and late Cretaceous, respectively. However, in places AFT ages vary significantly over relatively short distances and this has been interpreted to indicate local differential erosion levels controlled by tectonic displacements related to fault reactivation. A limitation of the AFT system is that it is sensitive to a temperature range of c. 120-60°C and therefore is unable to evaluate the magnitude of denudation episodes where the amounts are less than c. 1.5-2 km. So while the Cretaceous history of erosion is well established from existing AFTA data, the details of the timing and amount of erosion occurring during the Cenozoic remain relatively poorly constrained. The apatite (U

  18. Pore-Water Quality in the Clay-Silt Confining Units of the Lower Miocene Kirkwood Formation and Hypothetical Effects on Water Quality in the Atlantic City 800-Foot Sand, Northeastern Cape May County, New Jersey, 2001

    USGS Publications Warehouse

    Szabo, Zoltan; Keller, Elizabeth A.; Defawe, Rose M.

    2006-01-01

    Pore water was extracted from clay-silt core samples collected from a borehole at Ocean View, west of Sea Isle City, in northeastern Cape May County, New Jersey. The borehole intersects the lower Miocene Kirkwood Formation, which includes a thick sand and gravel unit between two clay-silt units. The sand and gravel unit forms a major confined aquifer in the region, known as the Atlantic City 800-foot sand, the major source of potable water along the Atlantic Coast of southern New Jersey. The pore water from the core is of interest because the borehole intersects the aquifer in an area where the ground water is sodium-rich and sulfidic. Locally in the aquifer in central and southern Cape May County, sodium concentrations are near the New Jersey secondary drinking-water standard of 50 mg/L (milligrams per liter), and typically are greater than 30 mg/L, but chloride and sulfate do not approach their respective secondary drinking-water standards except in southernmost Cape May County. Pore waters from the confining units are suspected to be a source of sodium, sulfur, and chloride to the aquifer. Constituent concentrations in filtered pore-water samples were determined using the inductively coupled plasma-mass spectrometry analytical technique to facilitate the determination of low-level concentrations of many trace constituents. Calcium-sodium-sulfate-bicarbonate, calcium-chloride-sulfate, calcium-sulfate, and sodium-sulfate-chloride-bicarbonate type waters characterize samples from the deepest part of the confining unit directly overlying the aquifer (termed the 'lower' confining unit). A sodium-chloride-sulfate type water is dominant in the composite confining unit below the aquifer. Sodium, chloride, and sulfate became increasingly dominant with depth. Pore water from the deepest sample recovered (1,390 ft (feet) below land surface) was brackish, with concentrations of sodium, chloride, and sulfate of 5,930, 8,400, and 5,070 mg/L, respectively. Pore-water samples

  19. Multiple, discrete inversion episodes revealed by apatite fission track analysis along the southernmost Atlantic margin of South Africa

    NASA Astrophysics Data System (ADS)

    Wildman, M.; Brown, R. W.; Persano, C.; Stuart, F. M.

    2013-12-01

    The morpho-tectonic history of the western South African continental margin and interior plateau remains enigmatic. Recent investigations of offshore sediment accumulation and interpretations of onshore structural and geomorphological observations have highlighted the complex geological evolution of South Africa throughout the Mesozoic and Cenozoic. Moreover, advances in geodynamic modelling approaches have explored the crustal response to varying styles of rifting and the influence of mantle upwelling beneath the African plate. These geological observations and models, however, require validation from quantitative constraints on the surface response (i.e. uplift and erosion) to syn- and post rift thermal and tectonic processes Over the last two decades, low temperature thermochronometry, particularly apatite fission track analysis (AFTA) and apatite (U-Th)/He, have been effective tools in providing these constraints by tracking the time-temperature history of rocks through c. 60 - 110°C and 80 - 40°C, respectively. The unique ability of AFTA to constrain both the timing and nature of sample cooling rests largely on the sensitivity of fission track annealing to temperature. Here, we present new AFT data from a suite of samples across the entire western continental margin of South Africa which contributes to a now extensive AFT dataset spanning the entire sub-continent. This dataset broadly invokes at least two discrete episodes of cooling driven by km scale denudation at c. 130 Ma, following rifting and break up of West Gondwana, and 90 Ma as a response to renewed tectonic uplift. However, the apparent lack of correlation of AFT age with elevation or with distance from the coast highlight the spatial and temporal variability of post-rift cooling that may be related to Mid-Cretaceous structural reactivation along the margin. We also present thermal history modelling using the Bayesian transdimensional inverse modelling approach of QTQt (Gallagher, 2012). Modelling

  20. An update of the tsetse fly (Diptera: Glossinidae) distribution and African animal trypanosomosis prevalence in north-eastern KwaZulu-Natal, South Africa.

    PubMed

    de Beer, Chantel J; Venter, Gert J; Kappmeier Green, Karin; Esterhuizen, Johan; de Klerk, Daniel G; Ntshangase, Jerome; Vreysen, Marc J B; Pienaar, Ronel; Motloang, Makhosazana; Ntantiso, Lundi; Latif, Abdalla A

    2016-06-09

    An unpredicted outbreak of African animal trypanosomosis or nagana in 1990 in north-eastern KwaZulu-Natal necessitated an emergency control programme, utilising the extensive cattledipping system in the area, as well as a reassessment of the tsetse and trypanosomosis problem in the province. Since 1990, sporadic blood sampling of cattle at the dip tanks in the naganainfested areas were undertaken to identify trypanosome species involved and to determine the infection prevalence in cattle. The distribution and species composition of the tsetse populations in the area were also investigated. From November 2005 to November 2007 selected dip tanks were surveyed for trypanosome infection prevalence. During April 2005 to August 2009 the distribution and abundance of tsetse populations were assessed with odour-baited H traps. The tsetse and trypanosome distribution maps were updated and potential correlations between tsetse apparent densities (ADs) and the prevalence of trypanosomosis were assessed. Glossina brevipalpis Newstead and Glossina austeni Newstead were recorded in locations where they have not previously been collected. No significant correlation between tsetse relative abundance and nagana prevalence was found, which indicated complex interactions between tsetse fly presence and disease prevalence. This was epitomised by data that indicated that despite large differences in the ADs of G. austeni and G. brevipalpis, trypanosome infection prevalence was similar in all three districts in the area. This study clearly indicated that both tsetse species play significant roles in trypanosome transmission and that it will be essential that any control strategy, which aims at sustainable management of the disease, should target both species.

  1. [Parasite fauna of the European Pilchard (Sardina Pilchardus Walbaum, 1792) from the Atlantic coastal water of North Africa: application of latitudinal patterns analysis for the host intraspecific structure].

    PubMed

    2013-01-01

    Two stocks of the European pilchard (Sardina pilchardus Walb.) from the Atlantic co- ast of Northwestern Africa were discriminated with the use of parasites as biological tags. A total of 646 fishes (TL = 15-25 cm; modal age 1-3) were examined for parasites in the area between 30-18 degree N during 2005-2010 winter and summer seasons. Fourteen species of parasites were found. Mean prevalence constituted 62%. The most abundant species (with prevalence 5% in at least one of the samples) included Goussia clupearum, Ceratonmyxa truncata, Cocomnxa morovi, Aphanurus stossichi, Lecitaster con!filsus, Bacciger bacciger, Hysterothylacium sp., and Anilocra capensis. All fishes were grouped into one-degree latitudinal groups. Analysis of parasite component communities in latitudinal groups allowed combining parasite component communities into northern (30-28 degree N) and southern (24-18 degree N) groups only in winter spawning season. These two groups cor- respond with two sardine stocks--"A + B" and "C" that were separated by FAO working group on the base of ecological and fishery data. Parasite component community of the stock "A + B" was characterized as balanced with dominant species B. bacciger. The parasite component community of the stock "C" was characterized as an unbalanced stock with Hysterothylacium sp. as the dominant species. Significant values of prevalence for G. clupearum A. stossichi, B. hacciger, Hysterothylacium sp., and A. capensis were revealed in fishes from stocks "A + B" and "C". These parasites may be used as biological tags that characterize specific of host-parasite complexes of northern and southern subareas examined. PMID:25507792

  2. [Parasite fauna of the European Pilchard (Sardina Pilchardus Walbaum, 1792) from the Atlantic coastal water of North Africa: application of latitudinal patterns analysis for the host intraspecific structure].

    PubMed

    Shukhgalter, O A

    2013-01-01

    Two stocks of the European pilchard (Sardina pilchardus Walb.) from the Atlantic co- ast of Northwestern Africa were discriminated with the use of parasites as biological tags. A total of 646 fishes (TL = 15-25 cm; modal age 1-3) were examined for parasites in the area between 30-18 degree N during 2005-2010 winter and summer seasons. Fourteen species of parasites were found. Mean prevalence constituted 62%. The most abundant species (with prevalence 5% in at least one of the samples) included Goussia clupearum, Ceratonmyxa truncata, Cocomnxa morovi, Aphanurus stossichi, Lecitaster con!filsus, Bacciger bacciger, Hysterothylacium sp., and Anilocra capensis. All fishes were grouped into one-degree latitudinal groups. Analysis of parasite component communities in latitudinal groups allowed combining parasite component communities into northern (30-28 degree N) and southern (24-18 degree N) groups only in winter spawning season. These two groups cor- respond with two sardine stocks--"A + B" and "C" that were separated by FAO working group on the base of ecological and fishery data. Parasite component community of the stock "A + B" was characterized as balanced with dominant species B. bacciger. The parasite component community of the stock "C" was characterized as an unbalanced stock with Hysterothylacium sp. as the dominant species. Significant values of prevalence for G. clupearum A. stossichi, B. hacciger, Hysterothylacium sp., and A. capensis were revealed in fishes from stocks "A + B" and "C". These parasites may be used as biological tags that characterize specific of host-parasite complexes of northern and southern subareas examined. PMID:25434194

  3. Very short-lived bromomethanes measured by the CARIBIC observatory over the North Atlantic, Africa and South-East Asia during 2009-2013

    NASA Astrophysics Data System (ADS)

    Wisher, A.; Oram, D. E.; Laube, J. C.; Mills, G. P.; van Velthoven, P.; Zahn, A.; Brenninkmeijer, C. A. M.

    2013-11-01

    Short-lived organic brominated compounds make up a significant part (~20%) of the organic bromine budget in the atmosphere. Emissions of these compounds are highly variable and there are limited measurements, particularly in the extra-tropical upper troposphere/lower stratosphere and tropical troposphere. Measurements of five short-lived bromomethanes (VSLB) were made in air samples collected on the CARIBIC project aircraft over three flight routes; Germany to Venezuela/Columbia during 2009-2011, Germany to South Africa during 2010 and 2011 and Germany to Thailand/Kuala Lumpur, Malaysia during 2012 and 2013. In the tropical troposphere, as the most important entrance region to the stratosphere, we observe a total mean organic bromine derived from these compounds across all flights at 10-12 km altitude of 3.4 ± 1.5 ppt. Individual mean tropical tropospheric mixing ratios across all flights were 0.43, 0.74, 0.14, 0.23 and 0.11 ppt for CHBr3, CH2Br2, CHBr2Cl, CHBrCl2 and CH2BrCl respectively. The highest levels of VSLS-derived bromine (4.20 ± 0.56 ppt) were observed in flights between Bangkok and Kuala Lumpur indicating that the South China Sea is an important source region for these compounds. Across all routes, CHBr3 and CH2Br2 accounted for 34% (4.7-71) and 48% (14-73) respectively of total bromine derived from the analysed VSLB in the tropical mid-upper troposphere totalling 82% (54-89). In samples collected between Germany and Venezuela/Columbia, we find decreasing mean mixing ratios with increasing potential temperature in the extra-tropics. Tropical mean mixing ratios are higher than extra-tropical values between 340-350 K indicating that rapid uplift is important in determining mixing ratios in the lower tropical tropopause layer in the West Atlantic tropics. O3 was used as a tracer for stratospherically influenced air and we detect rapidly decreasing mixing ratios for all VSLB above ~100 ppb O3 corresponding to the extra-tropical tropopause layer.

  4. Very short-lived bromomethanes measured by the CARIBIC observatory over the North Atlantic, Africa and Southeast Asia during 2009-2013

    NASA Astrophysics Data System (ADS)

    Wisher, A.; Oram, D. E.; Laube, J. C.; Mills, G. P.; van Velthoven, P.; Zahn, A.; Brenninkmeijer, C. A. M.

    2014-04-01

    Short-lived organic brominated compounds make up a significant part of the organic bromine budget in the atmosphere. Emissions of these compounds are highly variable and there are limited measurements, particularly in the extra-tropical upper troposphere/lower stratosphere and tropical troposphere. Measurements of five very short-lived bromomethanes (VSLB) were made in air samples collected on the CARIBIC project aircraft over three flight routes; Germany to Venezuela/Columbia during 2009-2011, Germany to South Africa during 2010 and 2011 and Germany to Thailand/Kuala Lumpur, Malaysia during 2012 and 2013. In the tropical troposphere, as the most important entrance region to the stratosphere, we observe a total mean organic bromine derived from these compounds across all flights at 10-12 km altitude of 3.4 ± 1.5 ppt. Individual mean tropical tropospheric mixing ratios across all flights were 0.43, 0.74, 0.14, 0.23 and 0.11 ppt for CHBr3, CH2Br2, CHBr2Cl, CHBrCl2 and CH2BrCl respectively. The highest levels of VSLB-derived bromine (4.20 ± 0.56 ppt) were observed in flights between Bangkok and Kuala Lumpur indicating that the South China Sea is an important source region for these compounds. Across all routes, CHBr3 and CH2Br2 accounted for 34% (4.7-71) and 48% (14-73) respectively of total bromine derived from the analysed VSLB in the tropical mid-upper troposphere totalling 82% (54-89). In samples collected between Germany and Venezuela/Columbia, we find decreasing mean mixing ratios with increasing potential temperature in the extra-tropics. Tropical mean mixing ratios are higher than extra-tropical values between 340-350 K indicating that rapid uplift is important in determining mixing ratios in the lower tropical tropopause layer in the West Atlantic tropics. O3 was used as a tracer for stratospherically influenced air and we detect rapidly decreasing mixing ratios for all VSLB above ∼100 ppb O3 corresponding to the extra-tropical tropopause layer.

  5. West Africa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    With its vast expanses of sand, framed by mountain ranges and exposed rock, northwestern Africa makes a pretty picture when viewed from above. This image was acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. The Canary Islands can be seen on the left side of the image just off Africa's Atlantic shore. The light brown expanse running through the northern two thirds of the image is the Sahara Desert. The desert runs up against the dark brown Haut Atlas mountain range of Morocco in the northwest, the Atlantic Ocean to the west and the semi-arid (light brown pixels) Sahelian region in the South. The Sahara, however, isn't staying put. Since the 1960s, the desert has been expanding into the Sahelian region at a rate of up to 6 kilometers per year. In the 1980s this desert expansion, combined with over cultivation of the Sahel, caused a major famine across west Africa. Over the summer months, strong winds pick up sands from the Sahara and blow them across the Atlantic as far west as North America, causing air pollution in Miami and damaging coral reefs in the Bahamas and the Florida Keys. The white outlines on the map represent country borders. Starting at the top-most portion of the map and working clockwise, the countries shown are Morocco, Western Sahara, Mauritania, Senegal, Mali, Burkina Fasso, Nigeria, Mali (again), and Algeria. Image by Reto Stockli, Robert Simmon, and Brian Montgomery, NASA Earth Observatory, based on data from MODIS

  6. South Atlantic interbasin exchange

    NASA Technical Reports Server (NTRS)

    Rintoul, Stephen Rich

    1991-01-01

    The exchange of mass and heat between the South Atlantic and the neighboring ocean basins was estimated using hydrographic data and inverse methods, in order to gain information on the links between the deep-water formation processes occurring within the Atlantic and the global thermohaline circulation. Results demonstrate that the global thermohaline cell associated with the formation and export of North Atlantic deep water (NADW) is closed primarily by a 'cold water path' in which deep water leaving the Atlantic ultimately returns as intermediate water entering the basin through Drake Passage. This conclusion conflicts with the suggestion by Gordon (1986) that the global thermohaline circulation associated with the formation of NADW is closed primarily by a 'warm water path', in which the export of NADW is compensated by an inflow of warm Indian Ocean thermocline water south of Africa.

  7. Two new species of the family Niphatidae van Soest, 1980 from Northeastern Brazil (Haplosclerida: Demospongiae: Porifera).

    PubMed

    Santos, George Garcia; Docio, Loyana; Pinheiro, Ulisses

    2014-03-06

    This paper deals with niphatid sponges from the coast of the Bahia State, northeastern coast of the Brazilian shelf (southwestern Atlantic). Two new species are described, Amphimedon estelae sp. nov. and Niphates luizae sp. nov. A taxonomic study of those samples is given, including description and illustrations. Both species were compared with their congeners present in the Atlantic Ocean.

  8. South Africa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    contained within South Africa's boundaries. In the upper righthand corner of the image is the Bay of Maputo, where sits Maputo, the capital of Mozambique. Fires are visible in the northeast corner of the image, near Maputo. Just north of Maputo is where the Limpopo River empties into the Indian Ocean. Tracing the Limpopo inland back toward the west, this river defines the northern boundary of South Africa with both Zimbabwe and Botswana. Johannesburg, the commercial capital of South Africa, can be seen as the greyish pixels in the northeastern region of the country. The country's legislative capital, Pretoria, is about 50 miles north of Johannesburg and 250 miles west of Maputo, in the heart of the Northern Province (formerly known as Transvaal). (Image courtesy Jacques Descloitres, MODIS Land Group, NASA Goddard Space Flight Center)

  9. MISR Images Northeastern Botswana

    NASA Technical Reports Server (NTRS)

    2000-01-01

    MISR images of the Ntwetwe and Sua Pans in northeastern Botswana, acquired on August 18, 2000 (Terra orbit 3553). The left image is a color view from the vertical-viewing (nadir) camera. On the right is a composite of red band imagery in which the 45-degree aft camera data are displayed in blue, 45-degree forward as green, and vertical as red. This combination causes wet areas to appear blue because of the glint-like reflection from water and damp surfaces. Clouds are visible in the upper left corner and right center of each image. The clouds look peculiar in the multi-angle view because geometric parallax resulting from their elevation above the surface causes a misregistration of the individual images making up the composite. This stereoscopic effect provides a way of distinguishing clouds from bright surfaces.

    The images are approximately 250 kilometers across. Ntwetwe and Sua pans are closed interior basins that catch rainwater and surface runoff during the wet season. Seasonal lakes form that may reach several meters in depth. During the dry season the collected waters rapidly evaporate leaving behind dissolved salts that coat the surface and turn it bright ('sua' means salt). The mining town of Sowa is located where the Sua Spit (a finger of grassland extending into the pan) attaches to the shore. Sowa represents headquarters for a JPL contingent carrying out MISR field experiments using the evaporite surface and the grasslands as targets and for Botswana scientists studying migration of groundwaters beneath the pans and surrounding areas. These efforts support the Southern Africa Regional Science Initiative (SAFARI-2000), which is now underway.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

    For more information: http://www-misr.jpl.nasa.gov

  10. 50 CFR 648.25 - Atlantic Mackerel, squid, and butterfish framework adjustments to management measures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Atlantic Mackerel, squid, and butterfish... OF THE NORTHEASTERN UNITED STATES Management Measures for the Atlantic Mackerel, Squid, and Butterfish Fisheries § 648.25 Atlantic Mackerel, squid, and butterfish framework adjustments to...

  11. 50 CFR 648.25 - Atlantic Mackerel, squid, and butterfish framework adjustments to management measures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Atlantic Mackerel, squid, and butterfish... OF THE NORTHEASTERN UNITED STATES Management Measures for the Atlantic Mackerel, Squid, and Butterfish Fisheries § 648.25 Atlantic Mackerel, squid, and butterfish framework adjustments to...

  12. 50 CFR 648.25 - Atlantic Mackerel, squid, and butterfish framework adjustments to management measures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Atlantic Mackerel, squid, and butterfish... OF THE NORTHEASTERN UNITED STATES Management Measures for the Atlantic Mackerel, Squid, and Butterfish Fisheries § 648.25 Atlantic Mackerel, squid, and butterfish framework adjustments to...

  13. Evolution of the Arctic-North Atlantic and the Western Tethys

    SciTech Connect

    Ziegler, P.A. )

    1988-01-01

    This volume provides an overview of the late Paleozoic to recent geological evolution of the continents and shelves bordering the North Atlantic Ocean, the Norwegian-Greenland Sea, the Arctic Ocean, and the Mediterranean Sea. The evolution of these seas has been the subject of many studies and compilations, which discuss the evolution of oceanic basins on the basis of their magnetic sea-floor anomalies. The volume presented combines this information with geological data from the adjacent shelf and onshore areas. It retraces the evolution of sedimentary basins developed during the rifting phases that preceded the opening of these oceans and highlights the scope of the associated intra-plate phenomena. The author presents a reconstruction of the late Paleozoic and early Mesozoic development of Europe, northernmost Africa and northeastern North America-Greenland and discusses the different orogenic cycles that accompanied the stepwise assembly of Pangea and the early rifting phases heralding its break-up.

  14. The morphotectonic history of the Atlantic continental margin of South Africa: insights from combined (U-Th)/He and fission track thermochronometry

    NASA Astrophysics Data System (ADS)

    Wildman, M.; Beucher, R.; Brown, R.; Persano, C.; Stuart, F.; Roelofse, F.

    2012-04-01

    The morphotectonic evolution of the South African continental margins and the interior plateau remains unresolved, with the crux of the debate being whether the present day topography represents an eroded remnant of a Cretaceous elevated interior or if the topography is much younger, developed as a result of Miocene epeirogenic-style uplift. In recent years, advances in the understanding of mantle dynamics have led to an appreciation of its importance as a major controlling factor on the evolution of the South African plateau since the break-up of Gondwana. However, constraints on the timing and amount of uplift derived from geodynamical models are still controversial due to a lack of tight constraints on mantle viscosity and density structure and because of differences in the way the plate motions at the surface are incorporated into the different models. It is therefore essential to obtain more directly relevant empirical observations that can be used to test these models. Low temperature thermochronology (LTT) is a powerful tool well able to address this question by providing constraints on the time-temperature history of rocks, denudation, landscape evolution and tectonic history. Over the past two decades, the main focus of LTT analysis in South Africa has been on Apatite Fission Track Analysis (AFTA) which generally supports a dominant Cretaceous (c. 90Ma) uplift event with km-scale erosion, but spatially as well as temporally variable, in the interior of the plateau. However, AFTA data is unable to provide robust constraints on the Tertiary cooling history due to the temperature range covered by the fission track system (e.g. 60-110°C). The (U-Th)/He method with a lower temperature range (c. 40-75°C) will therefore be more sensitive to more recent and smaller amounts of erosion offers a new opportunity to evaluate the magnitude of Cenozoic denudation in southern Africa. Here we present the first (U-Th)/He ages from SW South Africa, obtained from a transect

  15. Radiative Flux Changes by Aerosols from North America, Europe, and Africa over the Atlantic Ocean: Measurements and Calculations from TARFOX and ACE-2

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Hignett, P.; Livingston, J. M.; Schmid, B.; Chien, A.; Bergstrom, R.; Durkee, P. A.; Hobbs, P. V.; Bates, T. S.; Quinn, P. K.; Condon, Estelle (Technical Monitor)

    1998-01-01

    Aerosol effects on atmospheric radiative fluxes provide a forcing function that is a major source of uncertainty in understanding the past climate and predicting climate change. To help reduce this uncertainty, the 1996 Tropospheric Aerosol Radiative Forcing Experiment (TARFOX) and the 1997 second Aerosol Characterization Experiment (ACE-2) measured the properties and radiative effects of American, European, and African aerosols over the Atlantic. In TARFOX, radiative fluxes and microphysics of the American aerosol were measured from the UK C-130 while optical depth spectra, aerosol composition, and other properties were measured by the University of Washington C-131A and the CIRPAS Pelican. Closure studies show that the measured flux changes agree with those derived from the aerosol measurements using several modelling approaches. The best-fit midvisible single-scatter albedos (approx. 0.89 to 0.93) obtained from the TARFOX flux comparisons are in accord with values derived by independent techniques. In ACE-2 we measured optical depth and extinction spectra for both European urban-marine aerosols and free-tropospheric African dust aerosols, using sunphotometers on the R/V Vodyanitskiy and the Pelican. Preliminary values for the radiative flux sensitivities (Delta Flux / Delta Optical depth) computed for ACE-2 aerosols (boundary layer and African dust) over ocean are similar to those found in TARFOX. Combining a satellite-derived optical depth climatology with the aerosol optical model validated for flux sensitivities in TARFOX provides first-cut estimates of aerosol-induced flux changes over the Atlantic Ocean.

  16. Namib Desert, Namibia, Africa

    NASA Technical Reports Server (NTRS)

    1990-01-01

    One of the driest regions on Earth, the Namib Desert, Namibia, Africa (23.0N, 15.0E) lies adjacent to the Atlantic coast but the upwelling oceanic water causes a very stable rainless atmosphere. The few local inland rivers do not reach the sea but instead, appear as long indentations where they penetrate the dune fields and end as small dry lakes. The vast dune fields are the result of sands deposited over millions of years by the stream flow.

  17. Namib Desert, Namibia, Africa

    NASA Technical Reports Server (NTRS)

    1990-01-01

    One of the driest regions on Earth, the Namib Desert, Namibia, Africa (23.0N, 15.0E) lies adjacent to the Atlantic coast but upwelling oceanic water causes a very stable rainless atmosphere. The few local inland rivers do not reach the sea but instead appear as long indentations where rivers penetrate the dune fields and end as small dry lakes. The vast dune fields are the result of sands deposited over millions of years by the stream flow.

  18. Northeastern Exterior, Northwestern Exterior, & Southwestern Exterior Elevations, Northeastern Interior, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Northeastern Exterior, Northwestern Exterior, & Southwestern Exterior Elevations, Northeastern Interior, Southeastern Interior, & Southwestern Interior Elevations, Floor Plan, and Eastern Corner Detail - Manatoc Reservation, Vale Edge Adirondack, 1075 Truxell Road, Peninsula, Summit County, OH

  19. Late-glacial pollen, macrofossils and fish remains in northeastern U.S.A. — The Younger Dryas oscillation. A contribution to the 'North Atlantic seaboard programme' of IGCP-253, 'Termination of the Pleistocene'

    NASA Astrophysics Data System (ADS)

    Peteet, D. M.; Daniels, R. A.; Heusser, L. E.; Vogel, J. S.; Southon, J. R.; Nelson, D. E.

    The late-glacial environmental histories of Allamuchy Pond, New Jersey and Linsley Pond, Connecticut are reconstructed from pollen, macrofossil and fish scale remains. Accelerator mass spectrometry (AMS) 14C dating of seeds and needles indicates that the first organic deposition, evidenced by fossil Picea (spruce) needles, occurred approximately 12,400 BP. A major regional warming began in the northeastern United States at this time, correlative with the Bølling/Allerød warming of Europe and Greenland. The increase in Quercus (oak) pollen and presence of Pinus strobus (white pine) needles demonstrates the magnitude of warming reached at about 11,000 BP. The subsequent decline of thermophilous species and increase in boreal Picea, Abies (fir), Larix (larch), Betula papyrifera (paper birch) and Alnus (alder) from 10,800-10,000 BP was a regional vegetational reversal. Thus we find a North American expression of the Younger Dryas with a mean annual temperature depression of 3-4° C. The subsequent classical southern New England pine pollen zone 'B' and Pinus strobus macrofossils signalled a return to warmer conditions at approximately 10,000 BP, regionally, within approximately 50-100 years. A large increase in Quercus follows. This study is unique in documenting a continuous late-glacial record of fish remains from Allamuchy Pond, New Jersey sediments, indicating that members of the families Centrarchidae (sunfish), Salmonidae (trout), Percidae (perch) and Cyprinidae (minnow) were regionally present.

  20. A phylogenetic hypothesis for Crocodylus (Crocodylia) based on mitochondrial DNA: evidence for a trans-Atlantic voyage from Africa to the New World.

    PubMed

    Meredith, Robert W; Hekkala, Evon R; Amato, George; Gatesy, John

    2011-07-01

    The phylogenetic relationships among extant species of Crocodylus (Crocodylia) have been inconsistently resolved by previous systematic studies. Here we used nearly complete mitochondrial (mt) genomes (∼16,200 base pairs) for all described Crocodylus species, eight of which are new to this study, to derive a generally well-supported phylogenetic hypothesis for the genus. Model-based analyses support monophyly of all Asian+Australian species and paraphyly of Crocodylus niloticus (Nile crocodile) with a monophyletic New World clade nested within this species. Wild-caught Nile crocodiles from eastern populations group robustly with the four New World species to the exclusion of Nile crocodiles from western populations, a result that is also favored by parsimony analyses and by various subpartitions of the overall mt dataset. The fossil record of Crocodylus extends back only to the Late Miocene, while the earliest fossils assigned to C. niloticus and to New World Crocodylus are Pliocene. Therefore, in combination with paleontological evidence, mt DNA trees imply a relatively recent migration of Crocodylus from Africa to the Americas, a voyage that would have covered hundreds of miles at sea.

  1. Dust storm off Western Africa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The impacts of Saharan dust storms reach far beyond Africa. Wind-swept deserts spill airborne dust particles out over the Atlantic Ocean where they can enter trade winds bound for Central and North America and the Caribbean. This Moderate Resolution Imaging Spectroradiometer (MODIS) image shows a dust storm casting an opaque cloud of cloud across the Canary Islands and the Atlantic Ocean west of Africa on June 30, 2002. In general it takes between 5 and 7 days for such an event to cross the Atlantic. The dust has been shown to introduce foreign bacteria and fungi that have damaged reef ecosystems and have even been hypothesized as a cause of increasing occurrences of respiratory complaints in places like Florida, where the amount of Saharan dust reaching the state has been increasing over the past 25 years.

  2. The chronology and tectonic style of landscape evolution along the elevated Atlantic continental margin of South Africa resolved by joint apatite fission track and (U-Th-Sm)/He thermochronology

    NASA Astrophysics Data System (ADS)

    Wildman, Mark; Brown, Roderick; Beucher, Romain; Persano, Cristina; Stuart, Fin; Gallagher, Kerry; Schwanethal, James; Carter, Andrew

    2016-03-01

    Atlantic-type continental margins have long been considered "passive" tectonic settings throughout the entire postrift phase. Recent studies question the long-term stability of these margins and have shown that postrift uplift and reactivation of preexisting structures may be a common feature of a continental margin's evolution. The Namaqualand sector of the western continental margin of South Africa is characterized by a ubiquitously faulted basement but lacks preservation of younger geological strata to constrain postrift tectonic fault activity. Here we present the first systematic study using joint apatite fission track and apatite (U-Th-Sm)/He thermochronology to achieve a better understanding on the chronology and tectonic style of landscape evolution across this region. Apatite fission track ages range from 58.3 ± 2.6 to 132.2 ± 3.6 Ma, with mean track lengths between 10.9 ± 0.19 and 14.35 ± 0.22 µm, and mean (U-Th-Sm)/He sample ages range from 55.8 ± 31.3 to 120.6 ± 31.4 Ma. Joint inverse modeling of these data reveals two distinct episodes of cooling at approximately 150-130 Ma and 110-90 Ma with limited cooling during the Cenozoic. Estimates of denudation based on these thermal histories predict approximately 1-3 km of denudation coinciding with two major tectonic events. The first event, during the Early Cretaceous, was driven by continental rifting and the development and removal of synrift topography. The second event, during the Late Cretaceous, includes localized reactivation of basement structures as well as regional mantle-driven uplift. Relative tectonic stability prevailed during the Cenozoic, and regional denudation over this time is constrained to be less than 1 km.

  3. Fisheries. Population of origin of Atlantic cod.

    PubMed

    Nielsen, E E; Hansen, M M; Schmidt, C; Meldrup, D; Grønkjaer, P

    2001-09-20

    Most of the world's cod (Gadus morhua) fisheries are now tightly regulated or closed altogether. Being able to link individual fish to their population of origin would assist enormously in policing regulations and in identifying poachers. Here we show that microsatellite genetic markers can be used to assign individual cod from three different populations in the northeastern Atlantic Ocean to their population of origin. PMID:11565021

  4. Sex-structure, depth distribution, intermoult period and reproductive pattern of the deep-sea red crab Chaceon affinis (Brachyura, Geryonidae) in two populations in the north-eastern Atlantic

    NASA Astrophysics Data System (ADS)

    Biscoito, Manuel; Freitas, Mafalda; Pajuelo, José G.; Triay-Portella, Raül; Santana, José I.; Costa, Ana L.; Delgado, João; González, José A.

    2015-01-01

    This work investigated the biology of Chaceon affinis in two isolated populations of the Atlantic Ocean, including depth distribution, sexual structure, reproductive patterns and intermoult period. Males were larger and heavier than females. Mean size decreased with depth for both males and females. The highest abundance was found at 600-799 m of depth for males and at 800-999 m depth stratum for females. The highest abundance of ovigerous females was found at the 800-999 m depth stratum. Of the different ovaries' colour or colour shades recorded, only six categories were histologically characterized. The presence of spermatophores in the spermatheca of females in carapace stages II and III suggests that spermatophores are viable and used during the intermoult period. The size at sexual maturity in females was estimated at 104.4-104.7 mm carapace width (CW) in Madeira, and 109.3-110.5 mm CW in the Canary Islands. Only three categories of testes were identified. Mature testes consisted in a large mass, with highly coiled vasa deferentia visible to the naked eye. The size at sexual maturity in males was estimated at 113.8 mm CW in Madeira and 118.9 mm CW in the Canaries. The relative growth of males showed significant changes along the ontogeny and size at which allometric growth changes, as an indicator of morphometric maturity, occurred between 103.2 and 103.6 mm CW in Madeira and between 111.4 and 113.1 mm CW in the Canaries. In females, size at which allometric growth changes was found for maximum width of fifth abdominal somite (AS5W) at 98.2 mm CW in Madeira and 103.0 mm CW in the Canaries. The size at maturity obtained for C. affinis indicates that the minimum landing size (MLS) should not be set smaller than 125 mm CW in Madeira and 130 mm CW in the Canaries. This conservative MLS, higher than length at functional maturity, would safeguard immature individuals until they reach the size at which they can contribute to the reproductive capacity of the

  5. Morphological and genetic variation in North Atlantic giant file clams, Acesta spp. (Bivalvia: Limidae), with description of a new cryptic species in the northwest Atlantic.

    PubMed

    Gagnon, Jean-Marc; Kenchington, Ellen; Port, Antony; Anstey, Lynne J; Murillo, Francisco Javier

    2015-01-01

    We analyze the morphological and genetic variability within and between seven species of Acesta and specimens recently collected in the northwest Atlantic using traditional morphological measurements, landmark-based geometric morphometrics, and the cytochrome oxidase subunit I (COI) gene sequences, with particular emphasis on North Atlantic species. Shell morphology and external shell appearance do not allow reliable distinction between the widely recognized northeastern Atlantic A. excavata and other northwest Atlantic species or populations of Acesta, with the exception of A. oophaga. Similarly, shape analysis reveals a wide variability within northeastern Atlantic A. excavata, and significant morphological overlap with A. bullisi from the Gulf of Mexico and A. rathbuni from the southwestern Pacific and South China Sea. Specimens from the northwestern and Mid-Atlantic display shell shapes marginally similar to that of A. excavata. These differences are at least partly related to anterior or posterior shifting of the shell body and to the opposite shifting of the hinge line/dorsal region and upper lunule. These morphological variations, along with the midline-width-ratio, explain much of the variability extracted by principal component analysis. Results from a mitochondrial DNA barcode approach (COI), however, suggest that the northwest Atlantic specimens belong to a new species for which we propose the name Acesta cryptadelphe sp. nov. Differences in larval shell sizes between northeastern and northwestern Atlantic specimens are consistent with this result.

  6. Temporal chemical variations within lowermost jurassic tholeiitic magmas of the Central Atlantic Magmatic Province

    NASA Astrophysics Data System (ADS)

    Salters, Vincent J. M.; Ragland, P. C.; Hames, W. E.; Milla, K.; Ruppel, C.

    The Central Atlantic Magmatic Province (CAMP), of greater extent than any other large igneous province (LIP) yet identified surrounds the Central Atlantic in eastern North America, northeastern South America, western Africa, and southwestern Europe. It covers over 7×109 km2 and was active for no more than 4 Ma. Virtually all CAMP rocks are mafic tholeiites, and include both intrusives and extrusives. The most extensive intrusives, diabase (dolerite) dikes, occur in three main swarms on Pangaea: NW-, NE-, and NS trending. These mafic tholeiites can be classified based on their Ti contents into low-Ti (LTi), intermediate-Ti (ITi), and high-Ti (HTi). The NE swarm contains primarily the ITi magma type, whereas the NW swarm is heterogeneous and contains all three types. The N-S swarm contains highly evolved (high-Fe) quartz tholeiites in North America and ITi rocks in South America. These dike swarms can be correlated across the Atlantic basin on the basis of composition and attitude. The two principal magma types within the CAMP, LTi and ITi, were derived from mantle sources that were compositionally similar and contained both continental lithospheric and asthenospheric components. Compared with other large igneous provinces the CAMP basalts show depleted geochemical characteristics. Compositional differences between them are primarily due to differences in depth and degree of melting; LTi represents the deepest and greatest degrees of melting. The temporal progression of the chemical characteristics indicate deeper melting with time, which is consistent with a shallow (such as crustal thinning) and passive origin for the break-up of the Pangaean continent.

  7. Anisotropic tomography of the Atlantic ocean

    NASA Astrophysics Data System (ADS)

    Silveira, G.; Stutzmann, E.

    2003-04-01

    We present a regional tri-dimensional model of the Atlantic Ocean with anisotropy. The model, derived from Rayleigh and Love phase velocity measurements, is defined from the Moho down to 300 km depth with a lateral resolution of about 500 km and is presented in terms of average isotropic S-wave velocity, azimuthal anisotropy and transverse isotropy. The cratons beneath North America, Brazil and Africa are clearly associated with fast S-wave velocity anomalies. The Mid Atlantic Ridge is a shallow structure in the North Atlantic corresponding to a negative velocity anomaly down to about 150 km depth. In contrast, the ridge negative signature is visible in the South Atlantic down to the deepest depth inverted, that is 300~km depth. This difference is probably related to the presence of hot-spots along or close to the ridge axis in the South Atlantic and may indicate a different mechanism for the ridge between the North and South Atlantic. Negative velocity anomalies are clearly associated with hot-spots from the surface down to at least 300km depth, they are much broader that the supposed size of the hot-spots and seem to be connected along a North-South direction. Down to 100 km depth, a fast S-wave velocity anomaly is extenting from Africa into the Atlantic Ocean within the zone defined as the Africa superswell area. This result indicates that the hot material rising from below does not reach the surface in this area but may be pushing the lithosphere upward. In most parts of the Atlantic, the azimuthal anisotropy directions remain stable with increasing depth. Close to the ridge, the fast S-wave velocity direction is roughly parallel to the sea floor spreading direction. The hot-spot anisotropy signature is striking beneath Bermuda, Cape Verde and Fernando Noronha islands where the fast S-wave velocity direction seems to diverge radially from the hot-spots. The Atlantic average radial anisotropy is similar to that of the PREM model, that is positive down to about

  8. From Europe to America: Pliocene to Recent trans-Atlantic expansion of cold-water North Atlantic molluscs

    PubMed Central

    Vermeij, Geerat J

    2005-01-01

    Data on the geographical distribution, phylogeny and fossil record of cool-temperate North Atlantic shell-bearing molluscs that live in waters shallower than 100 m depth belong to two biogeographic provinces, one in eastern North America north of Cape Cod, the other in northern Europe. Amphi-Atlantic species, which are found in both provinces, comprise 30.8% of the 402 species in the northeastern Atlantic and 47.3% of the 262 species in the northwestern Atlantic. Some 54.8% of these amphi-Atlantic species have phylogenetic origins in the North Pacific. Comparisons among fossil Atlantic faunas show that amphi-Atlantic distributions became established in the Middle Pliocene (about 3.5 million years ago), and that all represent westward expansions of European taxa to North America. No American taxa spread eastward to Europe without human assistance. These results are in accord with previous phylogeographic studies among populations within several amphi-Atlantic species. Explanations for the unidirectional expansion of species across the Atlantic remain uncertain, but may include smaller size and greater prior extinction of the North American as compared to the European fauna and biased transport mechanisms. Destruction of the European source fauna may jeopardize faunas on both sides of the Atlantic. PMID:16271981

  9. Evolutionary diversity among Atlantic coast mangroves

    NASA Astrophysics Data System (ADS)

    Dodd, Richard S.; Rafii, Zara A.; Fromard, François; Blasco, François

    1998-06-01

    Current knowledge of intraspecific variation of mangrove species is limited in terms of rangewide distributions and is mostly restricted to morphological analyses, which have indicated a high degree of homogeneity. However, our analyses of the aliphatic hydrocarbon and triterpenoid fraction of foliar waxes (by gas chromatography and mass spectroscopy) of mangrove species ( Rhizophora mangle, Avicennia germinans and Laguncularia racemosa) from Gabon in West Africa and French Guiana in South America show significant genetic differentiation between eastern and western Atlantic provenances. The greater diversity in lipid composition, and the tendency for longer carbon chain lengths in all taxa from Africa, may suggest that American mangroves exhibit derived characteristics. A consequence of this hypothesis would be that Atlantic mangroves are unlikely to have dispersed from the Tethys via the Pacific, as has been proposed by some authors. More widespread sampling within the Atlantic and east Pacific region is needed to support and confirm these results.

  10. Southern Africa

    Atmospheric Science Data Center

    2013-04-16

    article title:  Southern Africa     View larger JPEG image ... visibility of smoke plumes and haze. The southern tip of South Africa is at the bottom of the image, and Zambia is at the top. ... MISR Team. Aug 25, 2000 - South Africa to Zambia including the Okavango Delta. project:  ...

  11. Tropical forcing of the recent rapid Arctic warming in northeastern Canada and Greenland.

    PubMed

    Ding, Qinghua; Wallace, John M; Battisti, David S; Steig, Eric J; Gallant, Ailie J E; Kim, Hyung-Jin; Geng, Lei

    2014-05-01

    Rapid Arctic warming and sea-ice reduction in the Arctic Ocean are widely attributed to anthropogenic climate change. The Arctic warming exceeds the global average warming because of feedbacks that include sea-ice reduction and other dynamical and radiative feedbacks. We find that the most prominent annual mean surface and tropospheric warming in the Arctic since 1979 has occurred in northeastern Canada and Greenland. In this region, much of the year-to-year temperature variability is associated with the leading mode of large-scale circulation variability in the North Atlantic, namely, the North Atlantic Oscillation. Here we show that the recent warming in this region is strongly associated with a negative trend in the North Atlantic Oscillation, which is a response to anomalous Rossby wave-train activity originating in the tropical Pacific. Atmospheric model experiments forced by prescribed tropical sea surface temperatures simulate the observed circulation changes and associated tropospheric and surface warming over northeastern Canada and Greenland. Experiments from the Coupled Model Intercomparison Project Phase 5 (ref. 16) models with prescribed anthropogenic forcing show no similar circulation changes related to the North Atlantic Oscillation or associated tropospheric warming. This suggests that a substantial portion of recent warming in the northeastern Canada and Greenland sector of the Arctic arises from unforced natural variability.

  12. Tropical forcing of the recent rapid Arctic warming in northeastern Canada and Greenland.

    PubMed

    Ding, Qinghua; Wallace, John M; Battisti, David S; Steig, Eric J; Gallant, Ailie J E; Kim, Hyung-Jin; Geng, Lei

    2014-05-01

    Rapid Arctic warming and sea-ice reduction in the Arctic Ocean are widely attributed to anthropogenic climate change. The Arctic warming exceeds the global average warming because of feedbacks that include sea-ice reduction and other dynamical and radiative feedbacks. We find that the most prominent annual mean surface and tropospheric warming in the Arctic since 1979 has occurred in northeastern Canada and Greenland. In this region, much of the year-to-year temperature variability is associated with the leading mode of large-scale circulation variability in the North Atlantic, namely, the North Atlantic Oscillation. Here we show that the recent warming in this region is strongly associated with a negative trend in the North Atlantic Oscillation, which is a response to anomalous Rossby wave-train activity originating in the tropical Pacific. Atmospheric model experiments forced by prescribed tropical sea surface temperatures simulate the observed circulation changes and associated tropospheric and surface warming over northeastern Canada and Greenland. Experiments from the Coupled Model Intercomparison Project Phase 5 (ref. 16) models with prescribed anthropogenic forcing show no similar circulation changes related to the North Atlantic Oscillation or associated tropospheric warming. This suggests that a substantial portion of recent warming in the northeastern Canada and Greenland sector of the Arctic arises from unforced natural variability. PMID:24805345

  13. Irrigation in northeastern Mississippi

    USGS Publications Warehouse

    Lang, J.W.; Boswell, E.H.

    1957-01-01

    The phenomenal increase in the use of water for agriculture, industry, and public water supply in the past few years has been an important factor in bringing about the current accelerated inventory and appraisal of the water resources of Mississippi. As a result of severe droughts during the past several years, and of the favorable results of experiments, the water resources of northeastern Mississippi today are rapidly being developed for irrigation. Records have shown that even during years of normal rainfall the distribution of the rain usually is such that supplementary irrigation can be profitably practiced on almost any crop. Although in northeaster Mississippi the annual precipitation generally is enough to support crops and pasture, short periods of drought are common. Supplemental irrigation protects against the periods of drought during the growing season and increases the yield and quality of crops.

  14. An inflated subpolar gyre blows life toward the northeastern Atlantic

    NASA Astrophysics Data System (ADS)

    Hátún, H.; Lohmann, K.; Matei, D.; Jungclaus, J. H.; Pacariz, S.; Bersch, M.; Gislason, A.; Ólafsson, J.; Reid, P. C.

    2016-09-01

    Deep convection in the Labrador and Irminger Seas inflates the cold and low-saline subpolar gyre, which is a rich nutrient and zooplankton source for the surrounding warmer waters of subtropical origin. The zooplankton abundances on the south Iceland shelf show characteristic sub-decadal variability, which closely reflect the oceanic abundances of the ecologically most important zooplankton species - Calanus finmarchicus. Much higher abundances of this species are observed during years when the winter mixed layer depths (MLD) in the Labrador-Irminger Sea, and over the Reykjanes Ridge are deep. Furthermore, a tight relationship is identified between on-shelf zooplankton abundances and lateral shifts of the biologically productive subarctic front southwest of Iceland. Thus, we suggest that northeastward expansion of the subpolar gyre results in biologically productive periods in the waters southwest of Iceland - both oceanic and on the shelf. In addition to local atmospheric forcing, we find that the MLD and frontal position are also impacted by remote heat losses and convection in the Labrador Sea, through northward advection of unstable mode waters. The sub-decadal oceanic and on-shelf biological production peaks are possibly predictable by half a year (local winter convection to subsequent summer production), and the advective time-lag from the Labrador Sea might induce an even longer predictability horizon (up to 1.5 years).

  15. Neotectonics in northeastern Brazil

    NASA Astrophysics Data System (ADS)

    Bezerra, Francisco Hilario Rego

    The thesis describes neotectonic deformation in the continental intraplate region of northeastern Brazil and explores its links with modern seismicity. The region, which is under E-W-oriented compression and N-S-oriented extension, shows shallow earthquake swarms which last for several years and include 5.0-5.2 mb events. Remote sensing, borehole and geophysical data, in conjunction with field structural information, indicate a continuous faulting process since the Miocene which has reactivated Cretaceous faults and Precambrian shear zones or in places generated new faults which cut across existing structures. Three main sets of faults are recognised across the area: a NE-striking set, a NW-striking set and a N-striking set. The first and the second sets are pervasive and their cross-cutting relationships show that they locally form a conjugate set and display both a strike-slip and a dip-slip component of movement. They have generated troughs filled by as much as 260 m of Cainozoic sediments. Radiocarbon dating shows that some of the faults slipped as recently as 4,041-3,689 cal. yr BP. Although the elevation of coastal deposits is consistent with the predictions of glacioisostatic models for the area, tectonic influence can be detected notably near the Carnaubais fault, where rapid emergence by at least 5 m to the east of Sao Bento occurred 4,080-2,780 cal. yr BP. Secondary ground failure, which includes hydroplastic deformation, liquefaction and landslides, can be seen in Quaternary alluvial sediments and is reported in the historical record. The present data show that the potential for large earthquakes in northeastern Brazil has been underestimated. Empirical relationships using liquefaction and surface rupture point to events of at least Ms=6.8 compared to a maximum mb = 5.2 recorded instrumentally. The finding that NE- and NW-trending faults are favourably orientated for reactivation in relation to the current stress field is of potential value for seismic

  16. Three new species of Eurypon Gray, 1867 from Northeastern Brazil (Poecilosclerida; Demospongiae; Porifera).

    PubMed

    Santos, George Garcia; França, Fernando; Pinheiro, Ulisses

    2014-12-15

    Three new species of Eurypon from Northeastern Brazil are described: Eurypon clavilectuarium sp. nov.; Eurypon suassunai sp. nov. and Eurypon distyli sp. nov. Samples were collected from the continental shelf of Rio Grande do Norte, Bahia and Paraíba States. While the majority of Atlantic Eurypon species have been described from deep water, two of three new species described in this study were collected from shallow depths. The three new species from Brazil were compared with all other eighteen Eurypon species described from the Atlantic

  17. East-looking view across Atlantic waters during MA-9 22 orbit

    NASA Technical Reports Server (NTRS)

    1963-01-01

    East looking view across Atlantic waters toward Africa, showing Mauritania and Spanish Sahara photographed from the Mercury-Atlas 9 capsule by Astronaut L. Gordon Cooper Jr., during his 22 orbit Mercury-Atlas 9 (MA-9) spaceflight.

  18. Linkages of Remote Sea Surface Temperatures and Atlantic Tropical Cyclone Activity Mediated by the African Monsoon

    SciTech Connect

    Taraphdar, Sourav; Leung, Lai-Yung R.; Hagos, Samson M.

    2015-01-28

    Warm sea surface temperatures (SSTs) in North Atlantic and Mediterranean (NAMED) can influence tropical cyclone (TC) activity in the tropical East Atlantic by modulating summer convection over western Africa. Analysis of 30 years of observations show that the NAMED SST is linked to a strengthening of the Saharan heat low and enhancement of moisture and moist static energy in the lower atmosphere over West Africa, which favors a northward displacement of the monsoonal front. These processes also lead to a northward shift of the African easterly jet that introduces an anomalous positive vorticity from western Africa to the main development region (50W–20E; 10N–20N) of Atlantic TC. By modulating multiple processes associated with the African monsoon, this study demonstrates that warm NAMED SST explains 8% of interannual variability of Atlantic TC frequency. Thus NAME SST may provide useful predictability for Atlantic TC activity on seasonal-to-interannual time scale.

  19. The first occurrence of the order Mormonilloida (Copepoda) in the tropical Southwest Atlantic Ocean.

    PubMed

    Melo, Pedro Augusto M C; De Melo Júnior, Mauro; Araújo, Moacyr; Neumann-Leitão, Sigrid

    2015-03-01

    This communication is the first report of the occurrence of the order Mormonilloida (Mormonilla phasma) in the tropical Southwestern Atlantic Ocean. Female individuals were found in surface waters from the shelf break state of Rio Grande do Norte (Northeastern Brazil) and between depths of 60 and 100 m in the epipelagic layer around the St. Peter and St. Paul Archipelago (equatorial Atlantic). This finding extends the vertical limits for this species.

  20. Tenarife Island, Canary Island Archipelago, Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Tenarife Island is one of the most volcanically active of the Canary Island archipelago, Atlantic Ocean, just off the NW coast of Africa, (28.5N, 16.5W). The old central caldera, nearly filled in by successive volcanic activity culminating in two stratocones. From those two peaks, a line of smaller cinder cones extend to the point of the island. Extensive gullies dissect the west side of the island and some forests still remain on the east side.

  1. Climate Forcing of North Atlantic Tropical Cyclone Activity over the last 6000 years

    NASA Astrophysics Data System (ADS)

    Donnelly, J. P.; Woodruff, J. D.; Scileppi, E.; Lane, P.

    2006-12-01

    Reconstructions of extreme overwash events in backbarrier lagoons and wetlands from the Caribbean to the northeastern United States show similar patterns of event occurrence. Comparisons with instrumental and historical records indicate that most of these overwash layers were likely deposited by landfalling tropical cyclones. Over the last 6000 years intense tropical cyclones have deposited coarse grained laminae in a coastal lagoon on Vieques, Puerto Rico. Intervals with more frequent intense tropical cyclone strikes occurred at 5600-4200 years ago, 2500-1000 years ago, and 250 years ago to present. Similarly records from backbarrier wetlands in the New York/New Jersey Bight provide evidence of more frequent overwash in the last 300 years and 2200 to 900 years ago. An earlier active interval in New York is also evident and dates to sometime before 2700 years ago. Other shorter records from the northeastern United States also provide evidence of more frequent storm-induced deposition over the last few hundred years following a relative lull in overwash and presumably tropical cyclone landfalls. This increase in tropical cyclone landfalls occurs during the later half of the Little Ice Age (LIA) when sea surface temperatures (SSTs) in the tropics were 2-3°C cooler than modern. Over the last several millennia a coherent pattern of climate change appears to have modulated intense tropical cyclone activity in the North Atlantic. The evolution of El Niño/Southern Oscillation (ENSO) variability over the late Holocene likely played an important role in controlling the frequency of intense tropical cyclones in the entire North Atlantic Basin, with intervals of fewer strong El Niño events being more favorable to intense tropical cyclone activity. In addition, variations in the West African monsoon, possibly tied to ENSO, may be an important control on the frequency of North Atlantic intense tropical cyclones. With increases in intense convective storms over tropical

  2. West Africa

    Atmospheric Science Data Center

    2013-04-16

    ... article title:  Hazy and Dusty Skies over Western Africa     View Larger Image ... the entire globe between 82 degrees north and 82 degrees south latitude. These data products were generated from a portion of the ...

  3. South Africa

    Atmospheric Science Data Center

    2013-04-16

    article title:  Red Tide Strands South African Rock Lobsters     ... and on atmospheric and oceanic conditions. At Elands Bay in South Africa's Western Cape province, about 1000 tons of rock lobsters beached ...

  4. Children's Literature from Northeastern Asia.

    ERIC Educational Resources Information Center

    Richardson, Maurine V.; And Others

    This paper presents an overview of three countries, China, Japan, and Korea, in the northeastern Asia region and provides a bibliography of children's literature from the area in the appendix. The document advocates that the global interdependence of societies necessitates an understanding of the cultures with which people must interrelate.…

  5. Cretaceous paleogeography of Africa

    SciTech Connect

    Hulver, M.L.; Ziegler, A.M.; Rowley, D.B.; Sahagian, D.

    1986-05-01

    Five stage-length maps (Valanginian, Aptian, Cenomanian, Coniacian, and Maestrichtian) of Africa integrate topography/bathymetry, lithofacies, tectonics, and climatically sensitive sediments. These reconstructions differ from currently available maps in their level of detail and accuracy, and in that computer routines were developed to plot all aspects of the maps, including lithofacies patterns. Bathymetric contours were determined from community paleoecology and from thermal subsidence models of the newly opening Atlantic and Indian oceans. Topographic contours have been estimated from uplift models of rift shoulders, as well as from the erosion and sedimentation record of both the internal and marginal basins. The uplift of rift shoulders from Nigeria to Sudan is suggested by the extensive Nubian and equivalent sandstones across north Africa. This Benue-Ngaoundere-Abu Gabra rift system approximately paralleled the paleoequator, and its shoulders must have experienced the high rainfall normally associated with the intertropical convergence zone (ITCZ). In fact, these mountains would have served as a high level heat source, and would have pinned the ITCZ to their summits. Such a system tends to reduce seasonal excursions of the ITCZ, and may have influenced the high biological productivity represented by the oil source rocks of the Arabian peninsula. These sources also lie on the equator and could have resulted from a shelf incursion of the equatorial divergence zone, which is controlled by the ITCZ.

  6. Observed Influence of Amazon rainfall on the Atlantic ITCZ and Atlantic Nino

    NASA Astrophysics Data System (ADS)

    Fu, R.; Wang, H.

    2007-05-01

    Most of previous studies on climate variabilities of the tropical Atlantic Ocean have been focused on remote and internal oceanic processes or atmosphere-ocean interaction. In comparison, relatively few studies have examined the influences from adjacent continents, especially the influence of rainfall over the South American continent. Using the Tropical Rainfall Measuring Mission (TRMM) daily rain-rate dada, the QuikSCAT ocean surface wind and PIRATA buoy data, we have found that convection developed over the Amazonia appears to propagate eastward across the Atlantic and then into Africa. Such changes modulate the intensity and location of the convection within the Atlantic ITCZ and result in a zonal oscillation of the ITCZ between the west and east equatorial Atlantic Ocean. The eastward propagating disturbances appear to be an atmospheric Kelvin wave with a period of 6 to 7 days and a phase speed of around 12 m s-1. Such convectively coupled Kelvin wave is particularly strong during boreal spring and dominates the synoptic variations of the lower and upper troposphere winds. Our results further suggest that the interannual changes of these convective coupled Kelvin waves have an important influence on trigging the onset of Atlantic Ninos. In particular, anomalously late northward withdraw of the South American rainfall in boreal spring lead to stronger Kelvin wave activities and stronger westerly wind anomalies in the western equatorial Atlantic. The latter triggers a change of the slope of the thermocline in the equatorial Atlantic Ocean and induces sea surface temperature anomalies in the eastern Atlantic. These changes contribute to the onset of the Atlantic Nino in earlier boreal summer.

  7. Early Mesozoic cooling from low temperature thermochronology in N Spain and N Africa

    NASA Astrophysics Data System (ADS)

    Grobe, R.; Alvarez-Marrón, J.; Glasmacher, U. A.; Menéndez-Duarte, R.

    2009-04-01

    , Volume 94, Issue 2, pp.193-203. Ghorbal, B.; Bertotti, G.; Foeken, J.; Andriessen, P. (2008). Unexpected Jurassic to Neogene vertical movements in ‘stable' parts of NW Africa revealed by low temperature geochronology. Terra Nova, Volume 20, Number 5, October 2008 , pp. 355-363(9). Jourdan, F.; Marzoli, A.; Bertrand, H.; Cosca, M.; Fontignie, D. (2003). The Northernmost CAMP: 40Ar/39Ar Age, petrology and Sr-Nd-Pb isotope geochemistry of the Kerforne Dike, Brittany, France. In: Hames, W.E., McHone, J.G., Renne, P.R., Ruppel, C. (Eds.), The Central Atlantic Magmatic Province: Insights From Fragments of Pangea. AGU, Geophys. Mon., vol. 136, pp. 209-226. Juez-Larré, J. (2003). Post Late Paleozoic tectonothermal evolution of the northeastern margin of Iberia, assessed by fission-track and (U-T)/He analysis: a case history from the Catalan Coastal Ranges. Ph.D. thesis, Free University of Amsterdam. 200 pp. Marzoli, A.; Renne, P.R.; Piccirillo, E.M.; Ernesto, M.; Bellieni, G.; De Min, A. (1999). Extensive 200-million-year-old continental food basalts of the Central Atlantic magmatic province. Science 284, 616-618. Pe-Piper, G.; Jansa, L.F.; Lambert, R.St.-J. (1992). Early Mesozoic magmatism of the Eastern Canadian margin. In: Puffer, J.H., Ragland, P.C. (Eds.), Eastern North American Mesozoic magmatism. Geol. Soc. Am., Spec. Paper, vol. 268, pp. 13-36. Wilson, M. (1997). Thermal evolution of the Central Atlantic passive margins: continental break-up above a Mesozoic super-plume. J. Geol. Soc. (Lond.) 154, 491-495.

  8. 76 FR 2640 - Fisheries of the Northeastern United States; Atlantic Bluefish Fishery; 2011 Atlantic Bluefish...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-14

    ..., economic, and social impacts of the recommendations. NMFS is responsible for reviewing these... in state waters. All federally permitted vessels fall into the definition of small businesses; thus... for bluefish (a low, medium, and high level of harvest). For analysis of impacts of each...

  9. 76 FR 17789 - Fisheries of the Northeastern United States; Atlantic Bluefish Fishery; 2011 Atlantic Bluefish...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-31

    ... considered to be synonymous with ``status quo'' management measures for 2010 since the alternative...., least restrictive commercial quota), but was not recommended because it is the status quo. Additionally.... The intent of this action is to establish the allowable 2011 harvest levels and other...

  10. 76 FR 65971 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Adjustment to the Atlantic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-25

    ... the sub-ACL is set aside for research (75 FR 48874, August 12, 2010). Due to the variability of Canadian catch in the New Brunswick weir fishery, a portion of the buffer between ABC and OY (the buffer to... the amount specified in the buffer. The NMFS Regional Administrator is required to monitor the...

  11. 78 FR 26523 - Fisheries of the Northeastern United States; Atlantic Bluefish Fishery; 2013 and 2014 Atlantic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-07

    ... supporting documents for the specifications, are available from Dr. Christopher M. Moore, Executive Director... published in the Federal Register on February 20, 2013 (78 FR 11809), and comments were accepted through..., 2013. Alan D. Risenhoover, Director, Office of Sustainable Fisheries, performing the functions...

  12. 77 FR 25100 - Fisheries of the Northeastern United States; Atlantic Bluefish Fishery; 2012 Atlantic Bluefish...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-27

    ... other supporting documents for the specifications, are available from Dr. Christopher M. Moore... published in the Federal Register on February 15, 2012 (77 FR 8776), and comments were accepted through... 24, 2012. Alan D. Risenhoover, Acting Deputy Assistant Administrator for Regulatory...

  13. Infectious Disease and the Demography of the Atlantic Peoples.

    ERIC Educational Resources Information Center

    Crosby, Alfred W.

    1991-01-01

    Discusses effects of disease on the Atlantic basin after Christopher Columbus established contact between the hemispheres. Emphasizes the decimation of the native populations of the Americas when exposed to illnesses common in Eurasia and Africa. Relates the epidemics to the development of the slave trade and the rise of the middle class in…

  14. Combined 40Ar/39Ar and Fission-Track study of the Freetown Layered Igneous Complex, Freetown, Sierra Leone, West Africa: Implications for the Initial Break-up of Pangea to form the Central Atlantic Ocean and Insight into the Post-rift Evolution of the Sie

    NASA Astrophysics Data System (ADS)

    Barrie, Ibrahim; Wijbrans, Jan; Andriessen, Paul; Beunk, Frank; Strasser-King, Victor; Fode, Daniel

    2010-05-01

    Sierra Leone lies within the south-western part of the West African Craton and comprises two major Archaean structural divisions: a low-grade granite-greenstone terrane characterised by N-S striking structures and a NW-SE striking highly metamorphosed belt of strained rocks that form the coastal margin of the craton. Intruded into the belt is the Freetown Layered Igneous Complex (FLIC), a tholeiitic magamtic body emplaced prior to or during the break-up of Pangea to form the Central Atlantic Ocean and, forming today the high ground of the coastal outline of Sierra Leone which is one of the most distinctive features on the West African coast. The break-up of Pangaea to form the Central Atlantic and its passive margins began in the Early Jurassic. Geo-tectonically, the break-up was particularly characterised by the formation of the Central Atlantic Magmatic Province (CAMP), covering once-contiguous parts of North America, Europe, Africa and South America. The FLIC forming part of the heart of CAMP is the largest single layered igneous intrusive yet known on either side of the Central Atlantic, measuring on surface, 65 x 14 x 7 km. Geophysical investigations indicate that the intrusion extends offshore to a depth of about 20 km. Geologically the Complex is a rhythmically layered elongated ultramafic-mafic lopolith divisible into 4 major zones each comprising repeated sequences of troctolitic, gabbroic and anorthositic rocks. An idealised unit of layering is from base upwards: dunite, troctolite, olivine-gabbro, leuco-gabbro, gabbro-norite and anorthosite cumulates. 40Ar-39Ar age spectra and 40Ar/36Ar versus 39Ar/36Ar isochron plots obtained by stepwise-heating experiments on plagioclases, biotites and amphiboles from troctolites, olivine-gabbros, gabbro-norites and anorthosites of the four zones yield plateau and isochron ages that seem to depict the cooling history of the Complex after emplacement. The biotites and some of the plagioclases and amphiboles give very

  15. Combined 40Ar/39Ar and Fission-Track study of the Freetown Layered Igneous Complex, Freetown, Sierra Leone, West Africa: Implications for the Initial Break-up of Pangea to form the Central Atlantic Ocean and Insight into the Post-rift Evolution of the Sie

    NASA Astrophysics Data System (ADS)

    Barrie, Ibrahim; Wijbrans, Jan; Andriessen, Paul; Beunk, Frank; Strasser-King, Victor; Fode, Daniel

    2010-05-01

    Sierra Leone lies within the south-western part of the West African Craton and comprises two major Archaean structural divisions: a low-grade granite-greenstone terrane characterised by N-S striking structures and a NW-SE striking highly metamorphosed belt of strained rocks that form the coastal margin of the craton. Intruded into the belt is the Freetown Layered Igneous Complex (FLIC), a tholeiitic magamtic body emplaced prior to or during the break-up of Pangea to form the Central Atlantic Ocean and, forming today the high ground of the coastal outline of Sierra Leone which is one of the most distinctive features on the West African coast. The break-up of Pangaea to form the Central Atlantic and its passive margins began in the Early Jurassic. Geo-tectonically, the break-up was particularly characterised by the formation of the Central Atlantic Magmatic Province (CAMP), covering once-contiguous parts of North America, Europe, Africa and South America. The FLIC forming part of the heart of CAMP is the largest single layered igneous intrusive yet known on either side of the Central Atlantic, measuring on surface, 65 x 14 x 7 km. Geophysical investigations indicate that the intrusion extends offshore to a depth of about 20 km. Geologically the Complex is a rhythmically layered elongated ultramafic-mafic lopolith divisible into 4 major zones each comprising repeated sequences of troctolitic, gabbroic and anorthositic rocks. An idealised unit of layering is from base upwards: dunite, troctolite, olivine-gabbro, leuco-gabbro, gabbro-norite and anorthosite cumulates. 40Ar-39Ar age spectra and 40Ar/36Ar versus 39Ar/36Ar isochron plots obtained by stepwise-heating experiments on plagioclases, biotites and amphiboles from troctolites, olivine-gabbros, gabbro-norites and anorthosites of the four zones yield plateau and isochron ages that seem to depict the cooling history of the Complex after emplacement. The biotites and some of the plagioclases and amphiboles give very

  16. Potential tropical Atlantic impacts on Pacific decadal climate trends

    NASA Astrophysics Data System (ADS)

    Chikamoto, Y.; Mochizuki, T.; Timmermann, A.; Kimoto, M.; Watanabe, M.

    2016-07-01

    The tropical Pacific cooling from the early 1990s to 2013 has contributed to the slowdown of globally averaged sea surface temperatures (SSTs). The origin of this regional cooling trend still remains elusive. Here we demonstrate that the remote impact of Atlantic SST anomalies, as well as local atmosphere-ocean interactions, contributed to the eastern Pacific cooling during this period. By assimilating observed three-dimensional Atlantic temperature and salinity anomalies into a coupled general circulation model, we are able to qualitatively reproduce the observed Pacific decadal trends of SST and sea level pressure (SLP), albeit with reduced amplitude. Although a major part of the Pacific SLP trend can be explained by equatorial Pacific SST forcing only, the origin of this low-frequency variability can be traced back further to the remote impacts of equatorial Atlantic and South Atlantic SST trends. Atlantic SST impacts on the atmospheric circulation can also be detected for the Northeastern Pacific, thus providing a linkage between Atlantic climate and Western North American drought conditions.

  17. Reorganization of the North Atlantic Oscillation during early Holocene deglaciation

    NASA Astrophysics Data System (ADS)

    Wassenburg, Jasper A.; Dietrich, Stephan; Fietzke, Jan; Fohlmeister, Jens; Jochum, Klaus Peter; Scholz, Denis; Richter, Detlev K.; Sabaoui, Abdellah; Spötl, Christoph; Lohmann, Gerrit; Andreae, Meinrat O.; Immenhauser, Adrian

    2016-08-01

    The North Atlantic Oscillation is the dominant atmospheric pressure mode in the North Atlantic region and affects winter temperature and precipitation in the Mediterranean, northwest Europe, Greenland, and Asia. The index that describes the sea-level pressure difference between Iceland and the Azores is correlated with a dipole precipitation pattern over northwest Europe and northwest Africa. How the North Atlantic Oscillation will develop as the Greenland ice sheet melts is unclear. A potential past analogue is the early Holocene, during which melting ice sheets around the North Atlantic freshened surface waters, affecting the strength of the meridional overturning circulation. Here we present a Holocene rainfall record from northwest Africa based on speleothem δ18O and compare it against a speleothem-based rainfall record from Europe. The two records are positively correlated during the early Holocene, followed by a shift to an anti-correlation, similar to the modern record, during the mid-Holocene. On the basis of our simulations with an Earth system model, we suggest the shift to the anti-correlation reflects a large-scale atmospheric and oceanic reorganization in response to the demise of the Laurentide ice sheet and a strong reduction of meltwater flux to the North Atlantic, pointing to a potential sensitivity of the North Atlantic Oscillation to the melting of ice sheets.

  18. Central Atlantic Magmatic Province (CAMP): The Palisade Sill Connection

    NASA Astrophysics Data System (ADS)

    Ghatak, A.; Basu, A. R.

    2012-12-01

    The extensively studied 200Ma Central Atlantic Magmatic Province (CAMP) is considered to be the world's largest continental Large Igneous Province (LIP) covering up to 7 X 106 km2. This igneous province has been linked to the ~200Ma Mesozoic opening of the Central Atlantic Ocean. This opening fragmented the CAMP into several segments that occur on four different tectonic plates today. The CAMP related LIP is different from others in that it constitutes almost entirely of dikes and sills with sparse volcanic outflows. The 200 Ma Palisade Sill, exposed along the Hudson River in northeastern North America is an expression of the CAMP magmatism. On the basis of similar ages of eruption, Palisade Sill tholeiites have been correlated to other CAMP exposures in four continents. We provide an isotopic tracer study of the Palisade Sill basalts and relate them to low-Ti (<2 wt %) CAMP related tholeiites from North and South America, western Europe, and West Africa. We report Nd-Sr-Pb isotopic and multiple trace element data of 19 basalts and gabbros, 3 chilled margin basalts, and 4 sandstones spanning the entire length and thickness of the Palisade Sill in New York and New Jersey. These geochemical data are essential to understand the relationship between mantle geodynamic processes involved in the generation of the CAMP tholeiites prior to the formation of the of the Atlantic Ocean crust. The Palisade Sill basalts of this study yield the typical composition of low-Ti CAMP tholeiites with small LREE enrichments (LaN/SmN = 1.7 to 2.3), radiogenic Sr and negative ɛNd(I) values (87Sr/87Sr(I) = 0.70668 to 0.71037; ɛNd(I) = -0.64 to -3.8), and Pb-isotopic ratios (e.g. 206Pb/204Pb = 18.11 to 18.69) above the NHRL and subparallel to it. These geochemical data indicate the Palisade Sill basalts were derived from a slightly enriched OIB-like mantle source. Further, these rocks were derived by ~15% melting of a slightly depleted spinel peridotite with up to 20% contamination by the

  19. High Diversity of Drosophilidae in High-Altitude Wet Forests in Northeastern Brazil.

    PubMed

    Monteiro, L S; Garcia, A C L; Oliveira, G F; Rohde, C

    2016-06-01

    The high-altitude wet forests of northeastern Brazil, locally known as "Brejos de Altitude," are enclaves of the Atlantic Forest situated above 500 m, surrounded by dryland vegetation, the Caatinga. The aim of this study was to characterize drosophilid communities in these upland forests, since few ecological studies on drosophilid communities have been conducted in northeastern Brazil. Four sites were investigated in three different times of the year throughout standardized traps. The results reveal the presence of 55 different species in a total of 13,064 specimens collected. The data were evaluated using ecological diversity measurements and compared with those obtained for other environments in the same geographic region. As for species composition, the Bonito upland forest, in a boundary forest location, stood out as having high species richness.

  20. Atlantic reef fish biogeography and evolution

    USGS Publications Warehouse

    Floeter, S.R.; Rocha, L.A.; Robertson, D.R.; Joyeux, J.C.; Smith-Vaniz, W.F.; Wirtz, P.; Edwards, A.J.; Barreiros, J.P.; Ferreira, C.E.L.; Gasparini, J.L.; Brito, A.; Falcon, J.M.; Bowen, B.W.; Bernardi, G.

    2008-01-01

    Aim: To understand why and when areas of endemism (provinces) of the tropical Atlantic Ocean were formed, how they relate to each other, and what processes have contributed to faunal enrichment. Location: Atlantic Ocean. Methods: The distributions of 2605 species of reef fishes were compiled for 25 areas of the Atlantic and southern Africa. Maximum-parsimony and distance analyses were employed to investigate biogeographical relationships among those areas. A collection of 26 phylogenies of various Atlantic reef fish taxa was used to assess patterns of origin and diversification relative to evolutionary scenarios based on spatio-temporal sequences of species splitting produced by geological and palaeoceanographic events. We present data on faunal (species and genera) richness, endemism patterns, diversity buildup (i.e. speciation processes), and evaluate the operation of the main biogeographical barriers and/or filters. Results: Phylogenetic (proportion of sister species) and distributional (number of shared species) patterns are generally concordant with recognized biogeographical provinces in the Atlantic. The highly uneven distribution of species in certain genera appears to be related to their origin, with highest species richness in areas with the greatest phylogenetic depth. Diversity buildup in Atlantic reef fishes involved (1) diversification within each province, (2) isolation as a result of biogeographical barriers, and (3) stochastic accretion by means of dispersal between provinces. The timing of divergence events is not concordant among taxonomic groups. The three soft (non-terrestrial) inter-regional barriers (mid-Atlantic, Amazon, and Benguela) clearly act as 'filters' by restricting dispersal but at the same time allowing occasional crossings that apparently lead to the establishment of new populations and species. Fluctuations in the effectiveness of the filters, combined with ecological differences among provinces, apparently provide a mechanism

  1. Two new species of Aulospongus Norman, 1878 with a key to the Atlantic species (Poecilosclerida; Demospongiae; Porifera).

    PubMed

    Cavalcanti, Thaynã; Santos, George Garcia; Pinheiro, Ulisses

    2014-07-03

    We describe two new species: Aulospongus trirhabdostylus sp. nov. and Aulospongus mandela sp. nov. from Potiguar Basin (Rio Grande do Norte State, Northeastern Brazil). Both species were compared with their congeners and an identification key for the Atlantic species of Aulospongus is provided. The genus Aulospongus now contains 16 species.

  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. South Africa, Namibia, and Botswana

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Pale green vegetation and red-brown deserts dominate this MODIS image of Namibia (left), Botswana (upper right), and the Republic of South Africa (bottom) acquired on June3, 2002. In central Namibia the mountainous terrain of Namaqualand is sandwiched between the Namib Desert on the Atlantic Coast and the Kalahari Desert to the interior, where white dots mark the location of small, impermanent lakes and ponds. Namaqualand is home to numerous rare succulent plants that can survive on the region.s scant rainfall as well as fog that blows in off the ocean. Namaqualand extends south of the Orange River, which runs along the border of Namibia and South Africa and into that country.s Northern Cape region. The Orange River extends almost all the way back through the country, and where it makes a sharp southward dip in this image (at lower right), it runs through the Asbestos Mountains, names for the naturally-occurring asbestos they contain. In southwestern South Africa, high plateaus, such as the Great Karoo become mountain ridges near the coast, and the city of Cape Town is visible as a grayish area of pixels on the north shores of the horseshoe-shaped False Bay at the Cape of Good Hope. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  4. Phanerozoic geological evolution of Northern and Central Africa: An overview

    NASA Astrophysics Data System (ADS)

    Guiraud, R.; Bosworth, W.; Thierry, J.; Delplanque, A.

    2005-10-01

    West African Craton (end Early Cambrian) and during the polyphased Hercynian-Variscan Orogeny that extended the final closure of the Paleotethys Ocean and resulted in the formation of the Maghrebian and Mauritanides belts. Only gentle deformation affected central and northeastern African during the Paleozoic, the latter remaining a passive margin of the Paleotethys Ocean up to the Early Permian when the development of the Neotethys initiated along the Eastern Mediterranean Basins. The Mesozoic-Cenozoic sedimentary sequence similarly consists of a succession of eustatically and tectonically controlled depositional cycles. Through time, progressive southwards shift of the basin margins occurred, related to the opening of the Neotethys Ocean and to the transgressions resulting from warming of the global climate and associated rise of the global sea level. The Guinean-Nigerian Shield, the Hoggar, Tibesti-Central Cyrenaica, Nubia, western Saudi Arabia, Central African Republic, and other long-lived arches delimited the principal basins. The main tectonic events were the polyphased extension, inversion, and folding of the northern African-Arabian shelf margin resulting in the development of the Alpine Maghrebian and Syrian Arc belts, rifting and drifting along the Central Atlantic, Somali Basins, and Gulf of Aden-Red Sea domains, inversion of the Murzuq-Djado Basin, and rifting and partial inversion along the Central African Rift System. Two major compressional events occurred in the Late Santonian and early Late Eocene. The former entailed folding and strike-slip faulting along the northeastern African-northern Arabian margin (Syrian Arc) and the Central African Fold Belt System (from Benue to Ogaden), and thrusting in Oman. The latter ("Pyrenean-Atlasic") resulted in folding, thrusting, and local metamorphism of the northern African-Arabian plate margin, and rejuvenation of intra-plate fault zones. Minor or more localized compressional deformations took place in the end

  5. Regional geologic framework off northeastern United States

    USGS Publications Warehouse

    Schlee, J.; Behrendt, John C.; Grow, J.A.; Robb, James M.; Mattick, R.; Taylor, P.T.; Lawson, B.J.

    1976-01-01

    Six multichannel seismic-reflection profiles taken across the Atlantic continental margin Previous HitoffTop the northeastern United States show an excess of 14 km of presumed Mesozoic and younger sedimentary rocks in the Baltimore Canyon trough and 8 km in the Georges Bank basin. Beneath the continental rise, the sedimentary prism thickness exceeds 7 km south of New Jersey and Maryland, and it is 4.5 km thick south of Georges Bank. Stratigraphically, the continental slope--outer edge of the continental shelf is a transition zone of high-velocity sedimentary rock, probably carbonate, that covers deeply subsided basement. Acoustically, the sedimentary sequence beneath the shelf is divided into three units which are correlated speculatively with the Cenozoic, the Cretaceous, and the Jurassic-Triassic sections. These units thicken offshore, and some have increased seismic velocities farther offshore. The uppermost unit thickens from a fraction of a kilometer to slightly more than a kilometer in a seaward direction, and velocity values range from 1.7 to 2.2 km/sec. The middle unit thickens from a fraction of a kilometer to as much as 5 km (northern Baltimore Canyon trough), and seismic velocity ranges from 2.2 to 5.4 km/sec. The lowest unit thickens to a maximum of 9 km (northern Baltimore Canyon), and velocities span the 3.9 to 5.9-km/sec interval. The spatial separation of magnetic and gravity anomalies on line 2 (New Jersey) suggests that in the Baltimore Canyon region the magnetic-slope anomaly is due to edge effects and that the previously reported free-air and isostatic gravity anomalies over the outer shelf may be due in part to a lateral increase in sediment density (velocity) near the shelf edge. The East Coast magnetic anomaly and the free-air gravity high both coincide over the outer shelf edge on line 1 (Georges Bank) but are offset by 20 km from the ridge on the reflection profile. Because the magnetic-slope-anomaly wavelength is nearly 50 km across, a

  6. Assessment of simulated rainfall and temperature from the regional climate model REMO and future changes over Central Africa

    NASA Astrophysics Data System (ADS)

    Fotso-Nguemo, Thierry C.; Vondou, Derbetini A.; Tchawoua, Clément; Haensler, Andreas

    2016-07-01

    This work investigates spatial and temporal changes in rainfall and temperature over Central Africa, using historical and representative concentration pathways (RCP2.6, RCP4.5 and RCP8.5) of the regional climate model REMO forced by two general climate models: the Europe-wide Consortium Earth System Model (EC-Earth) and the Max Planck Institute-Earth System Model (MPI-ESM). We found that in the present period (1980-2005), the spatial distribution of rainfall is simulated with an annual spatial pattern correlation coefficient (PCC) of 0.76 for REMO driven by EC-Earth and 0.74 for REMO driven by MPI-ESM respectively when compared to CRU data. In terms of temperature, the annual PCC is 0.93 for the two REMO outputs. According to the climatology of Central Africa, we subdivided the study area into five sub-regions, we also noticed that the annual and seasonal PCC depend on the considered sub-region. For the future period (2070-2095), temperature is projected to increase following all the three scenarios. The rainfall amount is projected to decrease by up to 5 mm/day towards the end of the twenty first century under RCP8.5 scenario, and by 1-2 mm/day under RCP4.5 and RCP2.6 scenarios over Equatorial Guinea, Gabon, Congo, north-western Democratic Republic of Congo (DRC) and the Lake Victoria. Significant decrease is predicted to occur mostly in the northern part of the domain under RCP8.5 scenario. However, future rainfall over High Lands of Cameroon, Adamawa Plateau, north-eastern DRC and Atlantic Ocean is projected to increase.

  7. Analogy between natural gas found in lakes of rift valley system of east Africa and its allied gas in Japan

    SciTech Connect

    Fukuta, O.

    1984-09-01

    The Afar triangle in northeastern Ethiopia is where the Red Sea rift, the Carlsberg Ridge of the Indian Ocean, and the Rift Valley system of east Africa meet. In 1979, J. Welhan and H. Craig reported that hydrothermal vents at 21/sup 0/N, on the East Pacific Rise, are discharging turbid waters. Mixtures of the plumes with ambient seawater contain significant amounts of dissolved H/sub 2/ and CH/sub 4/ as well as mantel-derived /sup 3/He-rich helium. The /sup 3/He//sup 4/He ratios of rock samples obtained earlier by J. Lupton and H. Craig from the Mid-Oceanic Ridge, including the Mid-Atlantic Ridge and the east Pacific Rise, are extremely high at an almost constant value of (1.3 +/- 0.2) x 10/sup -5/, which they defined as the MOR-type helium. However, the deep brines of the Red Sea contain about 1,000 times more methane than normal seawater does, according to Gold and Soter in 1980. Much evidence leads us to believe that large amounts of /sup 3/He-rich helium-bearing natural gas have been gushing out in many places of the Rift Valley of east Africa for a long time. In 1980, Gold and Soter stated that Lake Kivu, which occupies part of the East African rift valley, contains 50 million tons of dissolved methane for which there is no adequate microbial source. The Japanese Islands began to separate from the Asian continent during the early Miocene. The early Miocene was characterized by intensive volcanic activity that produced large amounts of pyroclastics and other volcanic rocks, generally called green tuff in Japan. It has been suggested that oil and gas in green tuff is derived from the upper mantle.

  8. Monitoring of persistent organic pollutants in Africa. Part 2: design of a network to monitor the continental and intercontinental background.

    PubMed

    Lammel, G; Dobrovolný, P; Dvorská, A; Chromá, K; Brázdil, R; Holoubek, I; Hosek, J

    2009-11-01

    A network for the study of long-term trends of the continental background in Africa and the intercontinental background of persistent organic pollutants as resulting from long-range transport of contaminants from European, South Asian, and other potential source regions, as well as by watching supposedly pristine regions, i.e. the Southern Ocean and Antarctica is designed. The results of a pilot phase sampling programme in 2008 and meteorological and climatological information from the period 1961-2007 was used to apply objective criteria for the selection of stations for the monitoring network: out the original 26 stations six have been rejected because of suggested strong local sources of POPs and three others because of local meteorological effects, which may prevent part of the time long-range transported air to reach the sampling site. Representativeness of the meteorological patterns during the pilot phase with respect to climatology was assessed by comparison of the more local airflow situation as given by climatological vs. observed wind roses and by comparison of backward trajectories with the climatological wind (NCEP/NCAR re-analyses). With minor exceptions advection to nine inspected stations was typical for present-day climate during the pilot phase, 2008. Six to nine stations would cover satisfyingly large and densely populated regions of North-eastern, West and East Africa and its neighbouring seas, the Mediterranean, Northern and Equatorial Atlantic Ocean, the Western Indian Ocean and the Southern Ocean. Among the more densely populated areas Southern Cameroon, parts of the Abessinian plateau and most of the Great Lakes area would not be covered. The potential of the network is not hampered by on-going long-term changes of the advection to the selected stations, as these do hardly affect the coverage of target areas.

  9. The African Diaspora: Mitochondrial DNA and the Atlantic Slave Trade

    PubMed Central

    Salas, Antonio; Richards, Martin; Lareu, María-Victoria; Scozzari, Rosaria; Coppa, Alfredo; Torroni, Antonio; Macaulay, Vincent; Carracedo, Ángel

    2004-01-01

    Between the 15th and 19th centuries ad, the Atlantic slave trade resulted in the forced movement of ∼13 million people from Africa, mainly to the Americas. Only ∼11 million survived the passage, and many more died in the early years of captivity. We have studied 481 mitochondrial DNAs (mtDNAs) of recent African ancestry in the Americas and in Eurasia, in an attempt to trace them back to particular regions of Africa. Our results show that mtDNAs in America and Eurasia can, in many cases, be traced to broad geographical regions within Africa, largely in accordance with historical evidence, and raise the possibility that a greater resolution may be possible in the future. However, they also indicate that, at least for the moment, considerable caution is warranted when assessing claims to be able to trace the ancestry of particular lineages to a particular locality within modern-day Africa. PMID:14872407

  10. Petrography of Archean Spherule Layers from the CT3 Drill Core, Barberton Greenstone Belt, South Africa

    NASA Astrophysics Data System (ADS)

    Hoehnel, D.; Reimold, W. U.; Mohr-Westheide, T.; Hofmann, A.; Altenberger, U.

    2016-08-01

    One of the major questions to be addressed in the core CT3 from the northeastern Barberton Greenstone Belt in South Africa is about the actual number of impact events represented by the 17 spherule layers over a stratigraphic interval of 150 m.

  11. Emissions from savanna fires in southern Africa

    NASA Astrophysics Data System (ADS)

    Sinha, Parikhit

    2004-12-01

    Airborne measurements are presented of emissions from savanna fires in southern Africa during the dry season. Measurements were obtained aboard the University of Washington Convair-580 research aircraft during the SAFARI 2000 field project in August and September 2000. Savanna fires in southern Africa emit a wide range of gaseous and particulate species including carbon, sulfur, nitrogen, halogen, and oxygenated compounds. Emission factors, emission ratios, and regional emissions of fifty trace gas and particulate species were derived, including eight species not previously reported in the literature (dimethyl sulfide, methyl nitrate, five species of hydrocarbons, and particles with diameters from 0.1--3 mum diameter). The physical, chemical, and radiative properties of the plume from a large savanna fire in South Africa are characterized, including plume dimensions, secondary formation of ozone and organic acids, oxidation of hydrocarbons, coagulation of particles, and gas-to-particle conversion in aged smoke. Numerous fires, thermodynamically stable layers aloft, and large-scale anticylonic flow result in high concentrations of air pollution distributed throughout the lower troposphere over southern Africa during the dry season. Average regional concentrations of CO (261 +/- 81 ppbv), SO2 (2.5 +/- 1.6 ppbv), O3 (64 +/- 13 ppbv), black particulate carbon (2.3 +/- 1.9 mug m-3), organic particulate carbon (6.2 +/- 5.2 mug m-3), total particle mass (26.0 +/- 4.7 mug m-3) are comparable to those found in polluted urban environments. The GEOS-CHEM model of tropospheric chemistry is used to characterize the transport of biomass burning emissions from southern Africa to the neighboring Atlantic and Indian Oceans during the dry season (May--October) of 2000. A large quantity of biomass burning emissions from southern Africa is transported westward over the latitudes 0--20°S to the southern Atlantic Ocean (˜40 Tg CO from May--October), contributing to a pollution anomaly

  12. Pacific and Atlantic Ocean influences on multidecadal drought frequency in the United States

    PubMed Central

    McCabe, Gregory J.; Palecki, Michael A.; Betancourt, Julio L.

    2004-01-01

    More than half (52%) of the spatial and temporal variance in multidecadal drought frequency over the conterminous United States is attributable to the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). An additional 22% of the variance in drought frequency is related to a complex spatial pattern of positive and negative trends in drought occurrence possibly related to increasing Northern Hemisphere temperatures or some other unidirectional climate trend. Recent droughts with broad impacts over the conterminous U.S. (1996, 1999–2002) were associated with North Atlantic warming (positive AMO) and northeastern and tropical Pacific cooling (negative PDO). Much of the long-term predictability of drought frequency may reside in the multidecadal behavior of the North Atlantic Ocean. Should the current positive AMO (warm North Atlantic) conditions persist into the upcoming decade, we suggest two possible drought scenarios that resemble the continental-scale patterns of the 1930s (positive PDO) and 1950s (negative PDO) drought. PMID:15016919

  13. Regional nitrogen budgets and riverine N & P fluxes for the drainages to the North Atlantic Ocean: Natural and human influences

    USGS Publications Warehouse

    Howarth, R.W.; Billen, G.; Swaney, D.; Townsend, A.; Jaworski, N.; Lajtha, K.; Downing, J.A.; Elmgren, Ragnar; Caraco, N.; Jordan, T.; Berendse, F.; Freney, J.; Kudeyarov, V.; Murdoch, P.; Zhu, Z.-L.

    1996-01-01

    We present estimates of total nitrogen and total phosphorus fluxes in rivers to the North Atlantic Ocean from 14 regions in North America, South America, Europe, and Africa which collectively comprise the drainage basins to the North Atlantic. The Amazon basin dominates the overall phosphorus flux and has the highest phosphorus flux per area. The total nitrogen flux from the Amazon is also large, contributing 3.3 Tg yr-1 out of a total for the entire North Atlantic region of 13.1 Tg yr-1. On a per area basis, however, the largest nitrogen fluxes are found in the highly disturbed watersheds around the North Sea, in northwestern Europe, and in the northeastern U.S., all of which have riverine nitrogen fluxes greater than 1,000 kg N km-2 yr-1. Non-point sources of nitrogen dominate riverine fluxes to the coast in all regions. River fluxes of total nitrogen from the temperate regions of the North Atlantic basin are correlated with population density, as has been observed previously for fluxes of nitrate in the world's major rivers. However, more striking is a strong linear correlation between river fluxes of total nitrogen and the sum of anthropogenically-derived nitrogen inputs to the temperate regions (fertilizer application, human-induced increases in atmospheric deposition of oxidized forms of nitrogen, fixation by leguminous crops, and the import/export of nitrogen in agricultural products). On average, regional nitrogen fluxes in rivers are only 25% of these anthropogenically derived nitrogen inputs. Denitrification in wetlands and aquatic ecosystems is probably the dominant sink, with storage in forests perhaps also of importance. Storage of nitrogen in groundwater, although of importance in some localities, is a very small sink for nitrogen inputs in all regions. Agricultural sources of nitrogen dominate inputs in many regions, particularly the Mississippi basin and the North Sea drainages. Deposition of oxidized nitrogen, primarily of industrial origin, is the

  14. 3. VIEW LOOKING NORTH WEST OVER CENTRAL ATLANTIC WITH ATLANTIC ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. VIEW LOOKING NORTH WEST OVER CENTRAL ATLANTIC WITH ATLANTIC OCEAN IN THE FOREGROUND. DENNIS HOTEL, BLENHEIM HOTEL, AND MARLBOROUGH HOTEL (LEFT TO RIGHT) ARE LOCATED IN THE CENTER OF THE PHOTOGRAPH. THE CLARIDGE HOTEL IS THE HIGHRISE IMMEDIATELY TO THE RIGHT OF THE MARLBOROUGH HOTEL - Marlborough, Blenheim & Dennis Hotels (aerial views), Between Park Place, Michigan Avenue & Boardwalk, Atlantic City, Atlantic County, NJ

  15. Pb isotopes in surficial pelagic sediments from the North Atlantic

    NASA Technical Reports Server (NTRS)

    Hamelin, B.; Grousset, F.; Sholkovitz, E. R.

    1990-01-01

    The concentration of Pb and its isotopic composition were measured in samples from the surface of sea-water sediments obtained from the northeastern Atlantic, the Sargasso Sea, and the U.S. continental shelf, with the purpose of investigating changes in Pb sources due to the anthropogenic perturbation that took place in modern times. It was found that the anthropogenic Pb input to marine sediments due to the increase of Pb contamination over the ocean during the last century could be identified in all these samples. However, samples from eastern and western Atlantic had very different Pb isotopic profiles, each reflecting the character of anthropogenic Pb emissions from the European and U.S. industries, respectively.

  16. Restoring a Ruptured Relationship: Barnard College's Caryl Phillips' Senior English Seminar Focuses on Broken International Connections and Culminates with a Trans-Atlantic Journey

    ERIC Educational Resources Information Center

    Keels, Crystal L.

    2004-01-01

    Millions of African people who were captured, kidnapped and shackled for sale as part of the trans-Atlantic slave trade first passed through Cape Coast Castle in Ghana, West Africa. They stepped through the doorway that set them on a horrifying journey across the Atlantic Ocean. Men, women and children were taken by force, leaving their loved…

  17. Shallow mtDNA coalescence in Atlantic pygmy angelfishes (genus Centropyge) indicates a recent invasion from the Indian Ocean.

    PubMed

    Bowen, B W; Muss, A; Rocha, L A; Grant, W S

    2006-01-01

    Pygmy angelfishes (genus Centropyge) are widespread and species-rich in the Indo-Pacific, but only three species are recognized in the Atlantic: Centropyge resplendens on the Mid-Atlantic Ridge, Centropyge argi in the Caribbean, and Centropyge aurantonotus in Brazil and the southern Caribbean. Atlantic species are distinguished only by color patterns and are very similar to Centropyge acanthops (Cac) in the western Indian Ocean, raising the possibility that pygmy angelfish recently invaded the Atlantic Ocean via southern Africa. To test this zoogeographic hypothesis, we compared a 454-bp segment of the mitochondrial DNA (mtDNA) control region among pygmy angelfishes of the subgenus Xiphypops, which includes the three Atlantic species, the Indian Ocean species, and an Indo-Pacific species [Centropyge fisheri (Cfi)]. The Indian Ocean species Cac is closest to the Atlantic species (d = 0.059) relative to Cfi (d = 0.077). The mtDNA genealogy indicates a colonization pathway from the Indian Ocean directly to the West Atlantic, followed by at least two waves of dispersal to the Mid-Atlantic Ridge. The gene tree for the three Atlantic species is polyphyletic, raising questions about taxonomic assignments based on color pattern. Mismatch distributions place Atlantic founder events and population expansions at about 250,000-500,000 years ago. Estimates of effective female population sizes from mismatch and coalescence analyses are consistent with founder events by tens of individuals in the western Atlantic, followed by expansions to several million individuals.

  18. O the Genesis of Anomalous SST and Rainfall Patterns Over the Tropical Atlantic Basin

    NASA Astrophysics Data System (ADS)

    Nobre, Paulo

    Empirical orthogonal functions (EOFs), correlation, and composite analyses are used to investigate the evolution of phenomena associated with sea surface temperature (SST) and rainfall variability over the tropical Atlantic. The most important findings in this research are as follows. 1. The well known droughts over northeastern Brazil (Nordeste) are a local manifestation of a much larger -scale anomalies pattern encompassing the whole equatorial Atlantic and Amazon region. 2. The large-scale dipole-like anomalous rainfall pattern over the equatorial Atlantic and Amazon in March, April, and May (MAM), which is the rainy season for Nordeste region, is a consequence of meridional displacements of the inter-tropical convergence zone (ITCZ). In particular, negative rainfall anomalies to the south of the equator during MAM are related to an early withdrawal of ITCZ towards the warm SST anomalies over the northern tropical Atlantic. Concurrent with the rainfall anomaly dipole, there are large-scale patterns of SST and wind stress over the tropical Atlantic Ocean which also show a prominent dipole-like structure. The dipole patterns of SST and surface wind stress are the most dominant mode of interannual variability. Weaker trade winds are associated with warmer SST; stronger trade winds with cooler SST. 3. The spatial structure of (dipole-like) anomalous SST, rainfall and surface wind stress during MAM are clearly a modulation of the annual cycle for that season. The similarity between the patterns of interannual variability and MAM seasonal anomalies (departure from the annual mean) is quite remarkable. 4. Previous work has suggested the direct influence of the El Nino/Southern Oscillation (ENSO) on the southern Atlantic. This study brings observational evidence that ENSO effect over the northern Atlantic may happen through teleconnection patterns into higher latitudes of the Northern Hemisphere. The teleconnection effects over the northern Atlantic are out of phase

  19. Tectonics of Atlantic Canada

    USGS Publications Warehouse

    Williams, H.; Dehler, S.A.; Grant, A.C.; Oakey, G.N.

    1999-01-01

    The tectonic history of Atlantic Canada is summarized according to a model of multiple ocean opening-closing cycles. The modern North Atlantic Ocean is in the opening phase of its cycle. It was preceded by an early Paleozoic lapetus Ocean whose cycle led to formation of the Appalachian Orogen. lapetus was preceded by the Neoproterozoic Uranus Ocean whose cycle led to formation of the Grenville Orogen. The phenomenon of coincident, or almost coincident orogens and modern continental margins that relate to repeated ocean opening-closing cycles is called the Accordion Effect. An understanding of the North Atlantic Ocean and its continental margins provides insights into the nature of lapetus and the evolution of the Appalachian Orogen. Likewise, an understanding of lapetus and the Appalachian Orogen raises questions about Uranus and the development of the Grenville Orogen. Modern tectonic patterns in the North Atlantic may have been determined by events that began before 1000 m.y.

  20. The arboreal component of a dry forest in Northeastern Brazil.

    PubMed

    Rodal, M J N; Nascimento, L M

    2006-05-01

    The dry forests of northeastern Brazil are found near the coastal zone and on low, isolated mountains inland amid semi-arid vegetation. The floristic composition of these dry montane forests, as well as their relationship to humid forests (Atlantic forest sensu stricto) and to the deciduous thorn woodlands (Caatinga sensu stricto) of the Brazilian northeast are not yet well known. This paper sought to determine if the arboreal plants in a dry forest growing on a low mountain in the semi-arid inland region (Serra Negra, 8 degrees 35 - 8 degrees 38 S and 38 degrees 02 - 38 degrees 04 W) between the municipalities of Floresta and Inajá, state of Pernambuco have the same floristic composition and structure as that seen in other regional forests. In fifty 10 x 20 m plots all live and standing dead trees with trunk measuring > 5 cm diameter at breast height were measured. Floristic similarities between the forest studied and other regional forests were assessed using multivariate analysis. The results demonstrate that the dry forest studied can be classified into two groups that represent two major vegetational transitions: (1) a humid forest/dry forest transition; and (2) a deciduous thorn-woodland/ dry forest transition.

  1. North Atlantic Oscillation records in Siberian tree rings

    NASA Astrophysics Data System (ADS)

    Sidorova, Olga; Saurer, Matthias; Siegwolf, Rolf

    2010-05-01

    Changes in the Eurasian subarctic like temperature increase, thawing of permafrost, changes in seasonality (shifting of the beginning of the growth period), and changes in the amount of precipitations are linked to a positive phase of North Atlantic Oscillation (NAO) in recent decades. We report about the response of larch trees to climatic changes in the eastern Taimyr (Central Siberia) and northeastern Yakutia (Eastern Siberia) at high latitudes during the last century using tree ring width, latewood density and stable isotope wood and cellulose (δ13C, δ18O) chronologies. Not only the summer months were related to the carbon and oxygen isotope variations. The positive relationship, which was found between February temperature and δ18O of cellulose for northeastern Yakutia and the negative correlations between the temperature of February and δ13C of wood and cellulose for eastern Taimyr, could be explained by the influence of North Atlantic Oscillation. This work was supported by Swiss National Science Foundation SNF 200021_121838/1 and RFBR_sibir 09-05-98015.

  2. Africa: Prosperous times

    SciTech Connect

    1996-08-01

    Political instability and corruption is the rule, rather than the exception, in Africa`s main producing regions, but exploration and production prospects there are bright and attractive to foreign operators. The paper discusses exploration, drilling, resource development, and production in Nigeria, Libya, Algeria, Egypt, Angola, Congo, Gabon, and Tunisia. The other countries of Africa are briefly mentioned, i.e., Cameroon, Cote D`Ivoire, South Africa, Sudan, Namibia, Equatorial Guinea, Eritrea, Zaire, Mozambique, Ghana, Niger, and Seychelles.

  3. New species and records of Anacroneuria (Plecoptera: Perlidae) from the northeastern semi-arid region of Brazil.

    PubMed

    Duarte, Tácio; Lecci, Lucas Silveira

    2016-01-01

    The genus Anacroneuria is widely distributed in the Neotropical Region. There are about 80 species listed from Brazil, five of which are recorded from the northeastern semi-arid region of Brazil, an area characterized by irregular and low precipitation. Examination of adult Anacroneuria material from this including areas of Caatinga desert vegetation and Atlantic forest revealed two new species records, A. debilis (Pictet) and A. terere Righi-Cavallaro & Lecci. Additionally, two new species, A. calori n. sp. and A. singela n. sp., are described from this material. These new records and new species reflect a major effort to document the biodiversity of the aquatic insects of the northeastern semi-arid region of Brazil by the Research Program in Semi-arid Biodiversity. PMID:27396007

  4. Africa's Geomosaic under Stress.

    ERIC Educational Resources Information Center

    de Blij, H. J.

    1991-01-01

    Traces the transformation of Subsaharan Africa during the last 35 years. Contends that the domino effect hastened decolonization and increased polarization within South Africa. Argues that modernization is taking place only in South Africa's core and that the geopolitical framework appears stable but may collapse from within. (NL)

  5. Oxygen Isotope Speleothem record of Decadal and Multidecadal Atlantic Oscillations over the last millennium in Southwestern Morocco

    NASA Astrophysics Data System (ADS)

    Ait Brahim, Yassine; Sha, LiJuan; Sifeddine, Abdelfettah; Cheng, Hai; Bouchaou, Lhoussaine; Da Cruz Junior, Francisco William; Khodri, Myriam; Peerbocus, Nawaaz; Mariller, Alexandre; Apaestegui, James; Guyot, Jean-Loup; Auler, Augusto; Hassane Beraaouz, El

    2016-04-01

    In this work, we present a stable oxygen isotope (δ18O) speleothem record from Ifoulki cave located South-West of Morocco (N 30°42'29'', W 09°19'39'' and 1267 meters above sea level). The age model, based on eighteen U-Th dates, reveals that the record covers the AD 790-1953 period with a data resolution of ~1.7 years. Stable oxygen isotope variations show substantial decadal to multi-decadal swings between dry and humid periods. The Medieval Climate Anomaly (MCA) is characterized by the longest period with δ18O values above the average, suggestive of pronounced drying possibly as a response to positive North Atlantic Oscillation (NAO) phases and increased volcanic activity during this period. However, at least two short wet phases are recognized during the MCA in Morocco, with peaks centered on the years AD 1040 and AD 1190 and seem to overlap with negative NAO phases as recorded in a recently published NAO reconstruction for the last millennium. During the next centuries, the NAO again depicts predominantly negative values and the δ18O drops below the average during the Little Ice Age (LIA). Furthermore, a striking resemblance is observed between our record and another recently published stalagmite record from the Piste cave in Northeastern Morocco, which is quite remarkable given the different type of tracers (δ18O vs. Mg and Sr) obtained from different environments (Western High Atlas vs. Northeastern Middle Atlas and ~634 km away). Comparison with regional paleorecords from other studies also reveals the replication of many characteristic climate features from the last millennium, first detected in Northern Morocco and the Iberian Peninsula. In particular, the evidence of generally dry conditions during the MCA and wetter conditions in the LIA, which is confirmed by all the paleorecords. These similarities indicate coherent climate variability in Northwest Africa and the Iberian Peninsula and suggest a strong regional control of the NAO during the last

  6. The Pivoting Motion of Africa in the Late Cretaceous and Early Cenozoic

    NASA Astrophysics Data System (ADS)

    Cande, S. C.

    2014-12-01

    Indo-Atlantic plate kinematics during the Late Cretaceous and early Cenozoic were characterized by two distinctive events: a period of unusually rapid motion of India starting around 70 Ma and lasting until roughly 50 Ma, and a large slowdown of Africa also starting around 70 Ma and also lasting roughly 20 Ma. The synchroneity of India's fastest motion (66 to 63 Ma) with the maximum outpouring of Deccan flood basalts has been noted by many, leading some to conclude that the speedup was caused by the arrival of the Reunion plume head at the Earth's surface. The slowdown of Africa starting at 70 Ma has not received as much attention, but the near synchroneity of this event with India's speedup is striking and suggests that it too may have been driven by the Reunion plume head. Establishing the connection between the changes in motion of India and Africa remains an outstanding problem. Cande and Stegman (2011) showed that an analysis of Africa's motion in which the stage poles constraining the relative motion of North America-Africa, South America-Africa and Antarctica-Africa are treated as velocity vectors reveal important aspects of Africa's motion that had not previously been noticed. Specifically they showed that Africa had a distinctive pivoting motion that started at the same time that India started to speed up. Here I use recently revised Antarctic-Africa stage poles to re-examine the pivoting motion of Africa. These rotations show that there were two distinctive events in Africa's motion. There was an initial, large slowdown (decrease in the rate of counterclockwise rotation) of Africa about a pivot point in the North Atlantic around 71 Ma, about the time India starts to speed up. This initial slowing was followed by a second event in which the change in motion was a gradual but prolonged increase in the rate of Africa's clockwise rotation about a pivot point in the South Atlantic that lasted from 68 Ma until 53 Ma, the period of the most rapid motion of India

  7. The Cretaceous opening of the South Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Granot, Roi; Dyment, Jérôme

    2015-03-01

    The separation of South America from Africa during the Cretaceous is poorly understood due to the long period of stable polarity of the geomagnetic field, the Cretaceous Normal Superchron (CNS, lasted between ∼121 and 83.6 Myr ago). We present a new identification of magnetic anomalies located within the southern South Atlantic magnetic quiet zones that have arisen due to past variations in the strength of the dipolar geomagnetic field. Using these anomalies, together with fracture zone locations, we calculate the first set of magnetic anomalies-based finite rotation parameters for South America and Africa during that period. The kinematic solutions are generally consistent with fracture zone traces and magnetic anomalies outside the area used to construct them. The rotations indicate that seafloor spreading rates increased steadily throughout most of the Cretaceous and decreased sharply at around 80 Myr ago. A change in plate motion took place in the middle of the superchron, roughly 100 Myr ago, around the time of the final breakup (i.e., separation of continental-oceanic boundary in the Equatorial Atlantic). Prominent misfit between the calculated synthetic flowlines (older than Anomaly Q1) and the fracture zones straddling the African Plate in the central South Atlantic could only be explained by a combination of seafloor asymmetry and internal dextral motion (<100 km) within South America, west of the Rio Grande fracture zone. This process has lasted until ∼92 Myr ago after which both Africa and South America (south of the equator) behaved rigidly. The clearing of the continental-oceanic boundaries within the Equatorial Atlantic Gateway was probably completed by ∼95 Myr ago. The clearing was followed by a progressive widening and deepening of the passageway, leading to the emergence of north-south flow of intermediate and deep-water which might have triggered the global cooling of bottom water and the end for the Cretaceous greenhouse period.

  8. Gaidropsarus (Gadidae, Teleostei) of the North Atlantic Ocean: a brief phylogenetic review.

    PubMed

    Francisco, S M; Robalo, J I; Stefanni, S; Levy, A; Almada, V C

    2014-08-01

    The phylogenetic relationships among the North Atlantic Gaidropsarus and between the three Gaidropsarinae genera Gaidropsarus, Ciliata and Enchelyopus are reviewed with the hitherto most comprehensive taxonomic sampling of this group. Phylogenetic results (maximum parsimony, maximum likelihood and Bayesian inference) based on nuclear (rhodopsin) and concatenated mitochondrial (12s, 16s and cytb) markers clearly support this subfamily. For the north-eastern Atlantic species of Gaidropsarus, two previously unreported clades were strongly supported, clarifying the relationships within the genus, and revealing fewer distinct taxa in the north Atlantic Gaidropsarus than previously stipulated. The data challenge the specific status of Gaidropsarus mediterraneus and Gaidropsarus guttatus and raise doubts concerning the distinctiveness of other species. A taxonomic revision of the genus is suggested. PMID:24961593

  9. Management of immigration and pregnancy screening in northeastern Italy.

    PubMed

    Tamaro, Giorgio; Parco, Sergio

    2011-01-01

    This study assesses the impact of immigration in Friuli Venezia Giulia, a region of northeastern Italy, on the epidemiological features of hemoglobin patterns and on prothrombotic and trisomy risk in pregnancy for patients of non-Italian origin. This study follows a series of studies on the incidence of thalassemia and other hemoglobinopathies with reduced globin chain synthesis, that were performed during the postwar (1939-45) period in Friuli Venezia Giulia following immigration into the region from Istria and Sardinia (regions of northern and central Italy). Current data show that today's constantly growing immigration into the region differs from previous decades, in terms of origin and quantity of migrants, who mainly come from third world countries. This has a significant impact on health care issues, and more specifically on prospective health screening for foreigners. The authors conclude that scholastic education and hospital services, either public or private, and voluntary associations, may contribute to solving the problem, but only in terms of training and organization, for non-European Union citizens arriving in northern Italy and neighboring areas, especially those from Africa, Asia, Latin America, and eastern Europe.

  10. North Atlantic Circulation

    NASA Astrophysics Data System (ADS)

    Molinari, R.; Bryan, K.; Schott, F.

    The intensity of the North Atlantic winddriven and thermohaline circulation and the close proximity of many oceanographic installations make the North Atlantic a particularly favored region of the world ocean from the standpoint of research in ocean circulation. Recent increases in available data and advances in numerical modeling techniques served as the impetus to convene a joint workshop of modelers and observers working on the North Atlantic with the Scientific Committee on Oceanic Research (SCOR) Working Group (WG) 68 (“North Atlantic Circulation”). Goals of the workshop were to provide an update on data sets and models and to discuss the poleward heat flux problem and possible monitoring strategies. The joint Workshop/SCOR WG-68 meeting was convened by F. Schott (chairman of the working group; Rosenstiel School of Marine and Atmospheric Science, Miami, Fla.), K. Bryan (National Oceanic and Atmospheric Administration/ Geophysical Fluid Dynamics Laboratory (NOAA/GFDL)), and R. Molinari (NOAA/Atlantic Oceanographic and Meteorological Laboratory (NOAA/AOML)).

  11. Atlantic Telehealth Knowledge Exchange.

    PubMed

    Dwyer, Patricia; Hagerman, Valerie; Ingram, Chris-Anne; MacFarlane, Ron; McCourt, Sherry

    2004-01-01

    Atlantic Canada has some of the earliest, most comprehensive, well-established networks, and innovative applications for telehealth in the country. The region offers a range of models for telehealth, in terms of management structure, coordination, funding, equipment, utilization, and telehealth applications. Collectively, this diversity, experience, and wealth of knowledge can significantly contribute to the development of a knowledge base for excellence in telehealth services. There is no formal process in place for the sharing of information amongst the provinces. Information sharing primarily occurs informally through professional contacts and participation in telehealth organizations. A core group of organizations partnered to develop a process for knowledge exchange to occur. This type of collaborative approach is favored in Atlantic Canada, given the region's economy and available resources. The Atlantic Telehealth Knowledge Exchange (ATKE) project centred on the development of a collaborative structure, information sharing and dissemination, development of a knowledge repository and sustainability. The project is viewed as a first step in assisting telehealth stakeholders with sharing knowledge about telehealth in Atlantic Canada. Significant progress has been made throughout the project in increasing the profile of telehealth in Atlantic Canada. The research process has captured and synthesized baseline information on telehealth, and fostered collaboration amongst telehealth providers who might otherwise have never come together. It has also brought critical awareness to the discussion tables of governments and key committees regarding the value of telehealth in sustaining our health system, and has motivated decision makers to take action to integrate telehealth into e-health discussions.

  12. Crustal structure of northeastern California

    NASA Astrophysics Data System (ADS)

    Zucca, John J.; Fuis, Gary S.; Milkereit, Bernd; Mooney, Walter D.; Catchings, Rufus D.

    1986-06-01

    In 1981, the U.S. Geological Survey conducted a seismic refraction survey of northeastern California designed to characterize the structure in four geologic provinces: the Klamath Mountains, Cascade Range, Modoc Plateau, and Basin and Range provinces. The survey consisted of north-south lines in the Klamath Mountains and Modoc Plateau provinces, northwest-southeast lines centered on Mount Shasta and Medicine Lake volcano, and an east-west line linking all the profiles. All lines except the east-west line ranged in length from 125 to 140 km, contained three shot points, and were recorded by 100 instruments. The east-west line was 260 km long, contained six shot points, and was recorded by 200 instruments. The Klamath and Modoc lines yielded the simplest models. The Klamath model is finely layered from the surface to at least 14-km depth, consisting of a series of high-velocity layers (6.1-6.7 km/s), ranging in thickness from 1 to 4 km, with alternating positive and negative velocity gradients. A layer with an unreversed velocity of 7.0 km/s extends from 14 km downward to an unknown depth. The Modoc model, in contrast, is thickly layered and has lower velocity at all depths down to 25 km. The uppermost layer, 4.5 km thick, consists of low-velocity material (2-4.5 km/s). Velocity beneath this layer is much higher (6.2 km/s) and increases slowly with depth. A small velocity step (to 6.4 km/s) is seen at 11 km, and a larger step (to 7.0 km/s) is seen at 25 km depth. Moho is probably 38-45 km deep under the Modoc Plateau, but its depth is unknown under the Klamath Mountains. Models for the Shasta and Medicine Lake lines show special features including low velocity (less than 3.5 km/s) in the edifice of Mount Shasta but high velocity (5.6 km/s) at shallow depth (1-2 km) under the summit of Medicine Lake volcano. The model for the east-west line consists of a western part similar to the Klamath model, an eastern part similar to the Modoc model, and laterally changing

  13. Regional paleogeographic evolution of west Africa: Implications for hydrocarbon exploration

    SciTech Connect

    Hempton, M.R.; Rosen, M.A.; Coughlin, R.M.; Scardina, A.D.; Hagen, E.S.; Nordstrom, P.J. )

    1991-03-01

    New paleogeographic reconstructions of west African continental margins provide a regional framework to contrast differences in hydrocarbon habitat and tectonostratigraphic style. Five regional provinces are delineated: (1) Northwest Africa margin from mauritania to Sierra Leone, (2) Transform margin from Liberia to Benin, (3) Niger delta of Nigeria, Cameroon, and Equatorial Guinea, (4) South Atlantic Salt basin margin from Cameroon to Angola, and (5) Southwest Africa margin of Namibia and South Africa. Computer-constrained paleogeographic reconstructions based on exploration data depict the separation of west Africa from South and North America during the Late Triassic to the present along three rift systems. In northwest Africa rifting began in the Late Triassic associated with the opening of the Central Atlantic. In southwest Africa rifting began between the southern tips of Africa and South America in the Early Cretaceous (Valanginian) and propagated northward to the Benue Trough, a broad zone of left-lateral shear and extensional basins that began to open in the Aptian. Between these two rift systems, the Transform margin rift system initiated in the Early Cretaceous (Barremain) as a wrench-fault dominated eastward extension of the Proto-Caribbean ocean that propagated to the Benue Trough by the middle Albian. The most important variables affecting the tectonostratigraphic and hydrocarbon evolution of the west African margins include (1) the geometry, kinematics, and duration of rifting; (2) distribution of rift basins relative to paleoclimate zones (which affects the deposition of lacustrine source rocks and evaporites while influencing the type and quantity of sediment derived from land); (3) sea-level fluctuations; and (4) distribution of deltaic and turbiditic depocenters.

  14. Sensitivity of the North Atlantic Basin to cyclic climatic forcing during the early Cretaceous

    USGS Publications Warehouse

    Dean, W.E.; Arthur, M.A.

    1999-01-01

    Striking cyclic interbeds of laminated dark-olive to black marlstone and bioturbated white to light-gray limestone of Neocomian (Early Cretaceous) age have been recovered at Deep Sea Drilling Project (DSDP) and Ocean Drilling Project (ODP) sites in the North Atlantic. These Neocomian sequences are equivalent to the Maiolica Formation that outcrops in the Tethyan regions of the Mediterranean and to thick limestone sequences of the Vocontian Trough of France. This lithologic unit marks the widespread deposition of biogenic carbonate over much of the North Atlantic and Tethyan seafloor during a time of overall low sealevel and a deep carbonate compensation depth. The dark clay-rich interbeds typically are rich in organic carbon (OC) with up to 5.5% OC in sequences in the eastern North Atlantic. These eastern North Atlantic sequences off northwest Africa, contain more abundant and better preserved hydrogen-rich, algal organic matter (type II kerogen) relative to the western North Atlantic, probably in response to coastal upwelling induced by an eastern boundary current in the young North Atlantic Ocean. The more abundant algal organic matter in sequences in the eastern North Atlantic is also expressed in the isotopic composition of the carbon in that organic matter. In contrast, organic matter in Neocomian sequences in the western North Atlantic along the continental margin of North America has geochemical and optical characteristics of herbaceous, woody, hydrogen-poor, humic, type III kerogen. The inorganic geochemical characteristics of the dark clay-rich (80% CaCO3) interbeds in both the eastern and western basins of the North Atlantic suggest that they contain minor amounts of relatively unweathered eolian dust derived from northwest Africa during dry intervals.

  15. Phylogeographic analysis reveals a deep lineage split within North Atlantic Littorina saxatilis

    PubMed Central

    Doellman, Meredith M.; Trussell, Geoffrey C.; Grahame, John W.; Vollmer, Steve V.

    2011-01-01

    Phylogeographic studies provide critical insight into the evolutionary histories of model organisms; yet, to date, range-wide data are lacking for the rough periwinkle Littorina saxatilis, a classic example of marine sympatric speciation. Here, we use mitochondrial DNA (mtDNA) sequence data to demonstrate that L. saxatilis is not monophyletic for this marker, but is composed of two distinct mtDNA lineages (I and II) that are shared with sister species Littorina arcana and Littorina compressa. Bayesian coalescent dating and phylogeographic patterns indicate that both L. saxatilis lineages originated in the eastern North Atlantic, around the British Isles, at approximately 0.64 Ma. Both lineages are now distributed broadly across the eastern, central and western North Atlantic, and show strong phylogeographic structure among regions. The Iberian Peninsula is genetically distinct, suggesting prolonged isolation from northeastern North Atlantic populations. Western North Atlantic populations of L. saxatilis lineages I and II predate the last glacial maximum and have been isolated from eastern North Atlantic populations since that time. This identification of two distinct, broadly distributed mtDNA lineages further complicates observed patterns of repeated incipient ecological speciation in L. saxatilis, because the sympatric origins of distinct ecotype pairs on eastern North Atlantic shores may be confounded by admixture of divergent lineages. PMID:21429920

  16. Phylogeographic analysis reveals a deep lineage split within North Atlantic Littorina saxatilis.

    PubMed

    Doellman, Meredith M; Trussell, Geoffrey C; Grahame, John W; Vollmer, Steve V

    2011-11-01

    Phylogeographic studies provide critical insight into the evolutionary histories of model organisms; yet, to date, range-wide data are lacking for the rough periwinkle Littorina saxatilis, a classic example of marine sympatric speciation. Here, we use mitochondrial DNA (mtDNA) sequence data to demonstrate that L. saxatilis is not monophyletic for this marker, but is composed of two distinct mtDNA lineages (I and II) that are shared with sister species Littorina arcana and Littorina compressa. Bayesian coalescent dating and phylogeographic patterns indicate that both L. saxatilis lineages originated in the eastern North Atlantic, around the British Isles, at approximately 0.64 Ma. Both lineages are now distributed broadly across the eastern, central and western North Atlantic, and show strong phylogeographic structure among regions. The Iberian Peninsula is genetically distinct, suggesting prolonged isolation from northeastern North Atlantic populations. Western North Atlantic populations of L. saxatilis lineages I and II predate the last glacial maximum and have been isolated from eastern North Atlantic populations since that time. This identification of two distinct, broadly distributed mtDNA lineages further complicates observed patterns of repeated incipient ecological speciation in L. saxatilis, because the sympatric origins of distinct ecotype pairs on eastern North Atlantic shores may be confounded by admixture of divergent lineages. PMID:21429920

  17. CHARCOAL-PRODUCING INDUSTRIES IN NORTHEASTERN BRAZIL

    EPA Science Inventory

    Charcoal workers in northeastern Brazil: Occupational risks and effects of exposure to wood smoke
    ABSTRACT
    Brazil has the largest production of charcoal in the world, which is used mostly in the iron and steel industries. In most of the production sites, the process is ba...

  18. Pathogenic Hantaviruses, Northeastern Argentina and Eastern Paraguay

    PubMed Central

    Martinez, Valeria P.; Bellomo, Carla; Maidana, Silvina; San Juan, Jorge; Tagliaferri, Paulina; Bargardi, Severino; Vazquez, Cynthia; Colucci, Norma; Estévez, Julio; Almiron, María

    2007-01-01

    We describe the first, to our knowledge, cases of hantavirus pulmonary syndrome in northeastern Argentina and eastern Paraguay. Andes and Juquitiba (JUQ) viruses were characterized. JUQV was also confirmed in 5 Oligoryzomys nigripes reservoir species from Misiones. A novel Akodon-borne genetic hantavirus lineage was detected in 1 rodent from the Biologic Reserve of Limoy. PMID:17953094

  19. Superintendent Communication Patterns in Northeastern Indiana

    ERIC Educational Resources Information Center

    Clendening, David Earl

    2009-01-01

    The purpose of the qualitative study was to examine the communication patterns of superintendents in Northeastern Indiana. The demand for accountability, transparency, and student achievement calls for today's superintendent to increase communication strategies and support the needs of the varied stakeholders. Today's public school leaders are…

  20. Molecular detection of the human pathogenic Rickettsia sp. strain Atlantic rainforest in Amblyomma dubitatum ticks from Argentina.

    PubMed

    Monje, Lucas D; Nava, Santiago; Eberhardt, Ayelen T; Correa, Ana I; Guglielmone, Alberto A; Beldomenico, Pablo M

    2015-02-01

    To date, three tick-borne pathogenic Rickettsia species have been reported in different regions of Argentina, namely, R. rickettsii, R. parkeri, and R. massiliae. However, there are no reports available for the presence of tick-borne pathogens from the northeastern region of Argentina. This study evaluated the infection with Rickettsia species of Amblyomma dubitatum ticks collected from vegetation and feeding from capybaras (Hydrochoerus hydrochaeris) in northeastern Argentina. From a total of 374 A. dubitatum ticks collected and evaluated by PCR for the presence of rickettsial DNA, 19 were positive for the presence of Rickettsia bellii DNA, two were positive for Rickettsia sp. strain COOPERI, and one was positive for the pathogenic Rickettsia sp. strain Atlantic rainforest. To our knowledge, this study is the first report of the presence of the human pathogen Rickettsia sp. strain Atlantic rainforest and Rickettsia sp. strain COOPERI in Argentina. Moreover, our findings posit A. dubitatum as a potential vector for this pathogenic strain of Rickettsia.

  1. Connection between South Mediterranean climate and North African atmospheric circulation during the last 50,000 yr BP North Atlantic cold events

    NASA Astrophysics Data System (ADS)

    Bout-Roumazeilles, V.; Combourieu Nebout, N.; Peyron, O.; Cortijo, E.; Landais, A.; Masson-Delmotte, V.

    2007-12-01

    High-resolution clay mineralogical analyses were performed on sediment deposited during the last 50,000 yr in the Alboran sea (ODP Site 976). The clay mineral record is compared with pollen assemblages and with annual precipitation (Pann) and mean temperatures of the coldest month (MTCO) reconstructed with the modern analog technique (MAT). Enhanced contribution of palygorskite, a typical wind-blown clay mineral, characterizes the North Atlantic cold climatic events. Coeval development of the semi-arid vegetation (Artemisia rich) associated with a drastic fall of reconstructed precipitations and temperatures, suggest cold and arid continental conditions in the West Mediterranean area during North Atlantic cold events. The clay mineral association, especially the palygorskite content and the illite-to-kaolinite ratio, indicate western Morocco as one of the major source of the clay-size fraction during the North Atlantic cold events. The maximum abundance of Artemisia associated with the presence of Argania pollen both indicate Morocco as the main origin for pollen during these cold periods. The comparison of these pollen and clay mineral-specific features allows us to pinpoint western Morocco as the dominant source of wind-blown particles during North Atlantic cold events. These specific mineralogical composition and palynological assemblages reveal enhanced aridity over North Africa and intensification of winds favouring dust erosion and transport from North Africa toward the Alboran Sea during the North Atlantic cold events. According to atmospheric models, such a meridian transport (1) likely results from the development of strong and stable anticyclonic conditions over the tropical Atlantic and North Africa, similar to today's summer meteorological configuration and (2) implies a northward position of the westerly winds during North Atlantic cold events. Finally the synoptic situation over the West Mediterranean during the North Atlantic cold events is compared

  2. Out of Africa and into an ice age: on the role of global climate change in the late Pleistocene migration of early modern humans out of Africa.

    PubMed

    Carto, Shannon L; Weaver, Andrew J; Hetherington, Renée; Lam, Yin; Wiebe, Edward C

    2009-02-01

    The results from two climate model simulations are used to explore the relationship between North Atlantic sea surface temperatures and the development of African aridity around 100,000 years ago. Through the use of illustrative simulations with an Earth System Climate Model, it is shown that freshwater fluxes associated with ice sheet surges into the North Atlantic, known as Heinrich events, lead to the southward shift of the intertropical convergence zone over Africa. This, combined with the overall increased aridity in the cooler mean climate, leads to substantial changes in simulated African vegetation cover, particularly in the Sahel. We suggest that Heinrich events, which occurred episodically throughout the last glacial cycle, led to abrupt changes in climate that may have rendered large parts of North, East, and West Africa unsuitable for hominin occupation, thus compelling early Homo sapiens to migrate out of Africa.

  3. Out of Africa and into an ice age: on the role of global climate change in the late Pleistocene migration of early modern humans out of Africa.

    PubMed

    Carto, Shannon L; Weaver, Andrew J; Hetherington, Renée; Lam, Yin; Wiebe, Edward C

    2009-02-01

    The results from two climate model simulations are used to explore the relationship between North Atlantic sea surface temperatures and the development of African aridity around 100,000 years ago. Through the use of illustrative simulations with an Earth System Climate Model, it is shown that freshwater fluxes associated with ice sheet surges into the North Atlantic, known as Heinrich events, lead to the southward shift of the intertropical convergence zone over Africa. This, combined with the overall increased aridity in the cooler mean climate, leads to substantial changes in simulated African vegetation cover, particularly in the Sahel. We suggest that Heinrich events, which occurred episodically throughout the last glacial cycle, led to abrupt changes in climate that may have rendered large parts of North, East, and West Africa unsuitable for hominin occupation, thus compelling early Homo sapiens to migrate out of Africa. PMID:19019409

  4. Fennerosquilla heptacantha (Crustacea: Stomatopoda: Squillidae) in South Atlantic Ocean.

    PubMed

    Lucatelli, Débora

    2015-01-01

    Fennerosquilla is a monotypic genus that belongs to the family Squillidae, which has the highest generic diversity within Stomatopoda. This genus has been recorded in the north Atlantic Ocean, the Gulf of Mexico and Caribbean Sea, between 105 and 458 m depth. The present specimen was collected during the project "Avaliação da Biota Bentônica e Planctônica na porção offshore das Bacias Potiguar e Ceará", in 2011, from the continental slope region of Brazil. In this expedition Fennerosquilla heptacantha was found at 178-193 m depth, and represents the first record of the species in the south Atlantic Ocean (Rio Grande do Norte State, northeastern Brazil), expanding the southern limit distribution. The specimen is the largest recorded, measuring 149 mm total length. The pigmentation zone on median region of telson and all diagnostic characters are still preserved and agree with the original description. Fennerosquilla heptacantha has a disjunct deep water distribution (more than 100 m) in the tropical western Atlantic, mostly along the continental slope. PMID:26624302

  5. Fennerosquilla heptacantha (Crustacea: Stomatopoda: Squillidae) in South Atlantic Ocean.

    PubMed

    Lucatelli, Débora

    2015-10-07

    Fennerosquilla is a monotypic genus that belongs to the family Squillidae, which has the highest generic diversity within Stomatopoda. This genus has been recorded in the north Atlantic Ocean, the Gulf of Mexico and Caribbean Sea, between 105 and 458 m depth. The present specimen was collected during the project "Avaliação da Biota Bentônica e Planctônica na porção offshore das Bacias Potiguar e Ceará", in 2011, from the continental slope region of Brazil. In this expedition Fennerosquilla heptacantha was found at 178-193 m depth, and represents the first record of the species in the south Atlantic Ocean (Rio Grande do Norte State, northeastern Brazil), expanding the southern limit distribution. The specimen is the largest recorded, measuring 149 mm total length. The pigmentation zone on median region of telson and all diagnostic characters are still preserved and agree with the original description. Fennerosquilla heptacantha has a disjunct deep water distribution (more than 100 m) in the tropical western Atlantic, mostly along the continental slope.

  6. [[History of Community Health in Africa. The Swiss Medical Missionaries' Endeavour in South Africa].

    PubMed

    Mabika, Hines

    2015-01-01

    It was not Dutch settlers nor British colonizers who introduced public and community health practice in north-eastern South Africa but medical doctors of the Swiss mission in southern Africa. While the history of medical knowledge transfer into 19th-20th century Africa emphasises colonial powers, this paper shows how countries without colonies contributed to expand western medical cultures, including public health. The Swiss took advantage of the local authorities' negligence, and implemented their own model of medicalization of African societies, understood as the way of improving health standards. They moved from a tolerated hospital-centred medicine to the practice of community health, which was uncommon at the time. Elim hospital's physicians moved back boundaries of segregationist policies, and sometime gave the impression of being involved in the political struggle against Apartheid. Thus, Swiss public health activities could later be seen as sorts of seeds that were planted and would partly reappear in 1994 with the ANC-projected national health policy.

  7. [[History of Community Health in Africa. The Swiss Medical Missionaries' Endeavour in South Africa].

    PubMed

    Mabika, Hines

    2015-01-01

    It was not Dutch settlers nor British colonizers who introduced public and community health practice in north-eastern South Africa but medical doctors of the Swiss mission in southern Africa. While the history of medical knowledge transfer into 19th-20th century Africa emphasises colonial powers, this paper shows how countries without colonies contributed to expand western medical cultures, including public health. The Swiss took advantage of the local authorities' negligence, and implemented their own model of medicalization of African societies, understood as the way of improving health standards. They moved from a tolerated hospital-centred medicine to the practice of community health, which was uncommon at the time. Elim hospital's physicians moved back boundaries of segregationist policies, and sometime gave the impression of being involved in the political struggle against Apartheid. Thus, Swiss public health activities could later be seen as sorts of seeds that were planted and would partly reappear in 1994 with the ANC-projected national health policy. PMID:26403059

  8. A new Crossodactylodes Cochran, 1938 (Anura: Leptodactylidae: Paratelmatobiinae) from the highlands of the Atlantic Forests of southern Bahia, Brazil.

    PubMed

    Teixeira, Mauro; Recoder, Renato Sousa; Amaro, Renata Cecília; Damasceno, Roberta Pacheco; Cassimiro, José; Rodrigues, Miguel Trefaut

    2013-01-01

    A new Crossodactylodes is described from Serra das Lontras, in the highlands of the Atlantic Forests of southern Bahia. The new species can be distinguished from all other Crossodactylodes by having Finger I ending in an acute tip, a larger body size, by cranial features, and by molecular data. Like their congeners, the new species live in bromeliads but is widely geographically disjunct, being apparently restricted to the summit of a mountain range in Northeastern Brazil. PMID:26146739

  9. Earthquakes in and near the northeastern United States, 1638-1998

    USGS Publications Warehouse

    Wheeler, R.L.; Trevor, N.K.; Tarr, A.C.; Crone, A.J.

    2000-01-01

    The data are those used to make a large-format, colored map of earthquakes in the northeastern United States and adjacent parts of Canada and the Atlantic Ocean (Wheeler, 2000; Wheeler and others, 2001; references in Data_Quality_Information, Lineage). The map shows the locations of 1,069 known earthquakes of magnitude 3.0 or larger, and is designed for a non-technical audience. Colored circles represent earthquake locations, colored and sized by magnitude. Short descriptions, colonial-era woodcuts, newspaper headlines, and photographs summarize the dates, times of day, damage, and other effects of notable earthquakes. The base map shows color-coded elevation, shaded to emphasize relief.

  10. Commonalities in Mercury Behavior in Contrasting Northeastern USA Landscapes

    NASA Astrophysics Data System (ADS)

    Shanley, J. B.; Scherbatskoy, T.; Schuster, P. F.; Reddy, M. M.; Chalmers, A.

    2001-05-01

    Generally less than 20% of atmospherically deposited mercury is exported from watersheds in streamflow, but the mercury export that does occur is highly episodic. Our research from diverse landscapes in northern New England, including small forested, agricultural, and urban watersheds as well as some larger rivers discharging to Lake Champlain and the Atlantic Ocean, indicates a consistent positive correlation between Hg concentrations and stream discharge. This relation appears to be driven by increased DOC, POC, and suspended sediment concentrations at increased streamflow. Streamwater Hg analyses pooled from 10 watersheds of diverse size and land use during the 2000 snowmelt within the Sleepers River Research Watershed in northeastern Vermont displayed a high correlation between (1) dissolved Hg and DOC, and (2) particulate Hg and POC. The same correlations held at Nettle Brook, a forested Vermont watershed 100 km west of Sleepers River. At Nettle Brook, DOC and dissolved mercury concentrations were both greater than at Sleepers River but the relation at the two sites was co-linear. In an agricultural watershed in northwestern Vermont, particulate Hg concentrations in streamflow were comparable to those at Nettle Brook despite markedly higher suspended sediment (and presumably POC) concentrations, suggesting the soil Hg pool is depleted by more frequent erosional events. The coupling of organic carbon with mercury may originate in the shallow soil zone; high concentrations of DOC and dissolved Hg were observed in O-horizon soil solution both at Nettle Brook and at some sites in the Adirondack Mountains of New York. Our findings underscore the importance of sampling during high-flow to determine accurate fluxes of Hg in streamflow. It is not clear, however, whether organic carbon actually controls Hg mobility, or whether organic carbon and Hg move in tandem simply as a result of their common source in soil organic matter.

  11. 75 FR 7435 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-19

    ... approximate OFL. This magnitude of catch provides a 24- to 32-percent buffer between OFL and ABC, which is consistent with general guidance on buffers for data- moderate to data-poor stocks.'' The SSC also noted ``that there should be a substantial buffer between OFL and ABC for data-poor stocks, an ABC based on...

  12. 75 FR 35435 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-22

    ... crab emergency action implemented by NMFS (74 FR 9770, March 6, 2009), i.e., a target TAC of 3.56..., 2010 final rule implementing the FY 2010 red crab specifications (75 FR 27219), that rule set the... catch (TAC) and a fleet-wide days-at-sea (DAS) allocation. However, the implementing regulations for...

  13. 75 FR 27219 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-14

    ... crab fishery, including a target total allowable catch (TAC) and a fleet-wide days-at-sea (DAS... England Fishery Management Council (Council) to recommend, on a triennial basis, a target TAC and a fleet... emergency rule to modify the 2009 target TAC and fleet DAS to be consistent with the recommendations of...

  14. Atmospheric Chemistry Over Southern Africa

    NASA Technical Reports Server (NTRS)

    Gatebe, Charles K.; Levy, Robert C.; Thompson, Anne M.

    2011-01-01

    During the southern African dry season, regional haze from mixed industrial pollution, biomass burning aerosol and gases from domestic and grassland fires, and biogenic sources from plants and soils is worsened by a semi-permanent atmosphere gyre over the subcontinent. These factors were a driver of several major international field campaigns in the 1990s and early 2000s, and attracted many scientists to the region. Some researchers were interested in understanding fundamental processes governing chemistry of the atmosphere and interaction with climate change. Others found favorable conditions for evaluating satellite-derived measurements of atmospheric properties and a changing land surface. With that background in mind a workshop on atmospheric chemistry was held in South Africa. Sponsored by the International Commission for Atmospheric Chemistry and Global Pollution (ICACGP; http://www.icacgp.org/), the workshop received generous support from the South African power utility, Eskom, and the Climatology Research Group of the University of the Witwatersrand, Johannesburg, South Africa. The purpose of the workshop was to review some earlier findings as well as more recent findings on southern African climate vulnerability, chemical changes due to urbanization, land-use modification, and how these factors interact. Originally proposed by John Burrows, president of ICACGP, the workshop was the first ICACGP regional workshop to study the interaction of air pollution with global chemical and climate change. Organized locally by the University of the Witwatersrand, the workshop attracted more than 60 delegates from South Africa, Mozambique, Botswana, Zimbabwe, France, Germany, Canada, and the United States. More than 30 presentations were given, exploring both retrospective and prospective aspects of the science. In several talks, attention was focused on southern African chemistry, atmospheric pollution monitoring, and climate processes as they were studied in the field

  15. What role does crustal heterogeneity play on continental break-up; the interplay of a foldbelt, rift system and ocean basin in the South Atlantic

    NASA Astrophysics Data System (ADS)

    Paton, Douglas; Mortimer, Estelle; Hodgson, Neil

    2015-04-01

    Although extensively studied, two key questions remain unanswered regarding the evolution of the southern South Atlantic. Firstly, where is the Cape Foldbelt (CFB) in offshore South Africa? The CFB is part of the broader Gonwanian Orogeny that prior to South Atlantic rifting continued into the Ventana Foldbelt of Argentina but to date its location in the offshore part of South Africa remains enigmatic. Secondly, the conjugate rift basin to South Africa is the Colorado Basin in Argentina but why does it trend east-west despite its perpendicular orientation to the Atlantic spreading ridge? Current plate models and structural understands cannot explain these fundamental questions. We use newly acquired deep reflection seismic data in the Orange Basin, South Africa, to develop a new structural model for the southern South Atlantic. We characterise the geometry of the Cape Foldbelt onshore and for the first time correlate it into the offshore. We show that it has a north-south trend immediately to the north of the Cape Peninsula but then has a syntaxis (Garies syntaxis) that results in a change to an east-west orientation. This forms the missing jigsaw piece of the Atlantic reconstruction as this is directly beside the restored Colorado Basin. When considered within the pre-break up structural configuration our observations imply that prior to the main phase of Atlantic rifting in the Mezosoic there was significant variation in crustal geometry incorporating the Orange Basin of South Africa, the Colorado Basin and the Gariep Belt of Namibia. These faults were active during Gondwana rifting, but the Colorado rift failed resulting in the present day location of the South Atlantic. Not only do our results improve our understanding of the evolution of the South Atlantic ocean, they highlight the importance of differentiating between early rift evolution and strain localisation during the subsequent rift phase prior to seafloor spreading.

  16. Array seismological investigation of the South Atlantic 'Superplume'

    NASA Astrophysics Data System (ADS)

    Hempel, Stefanie; Gassmöller, Rene; Thomas, Christine

    2015-04-01

    We apply the axisymmetric, spherical Earth spectral elements code AxiSEM to model seismic compressional waves which sample complex `superplume' structures in the lower mantle. High-resolution array seismological stacking techniques are evaluated regarding their capability to resolve large-scale high-density low-velocity bodies including interior structure such as inner upwellings, high density lenses, ultra-low velocity zones (ULVZs), neighboring remnant slabs and adjacent small-scale uprisings. Synthetic seismograms are also computed and processed for models of the Earth resulting from geodynamic modelling of the South Atlantic mantle including plate reconstruction. We discuss the interference and suppression of the resulting seismic signals and implications for a seismic data study in terms of visibility of the South Atlantic `superplume' structure. This knowledge is used to process, invert and interpret our data set of seismic sources from the Andes and the South Sandwich Islands detected at seismic arrays spanning from Ethiopia over Cameroon to South Africa mapping the South Atlantic `superplume' structure including its interior structure. In order too present the model of the South Atlantic `superplume' structure that best fits the seismic data set, we iteratively compute synthetic seismograms while adjusting the model according to the dependencies found in the parameter study.

  17. Patterns of distribution of deepwater demersal fishes of the North Atlantic mid-ocean ridge, continental slopes, islands and seamounts

    NASA Astrophysics Data System (ADS)

    Bergstad, Odd Aksel; Menezes, Gui M. M.; Høines, Åge S.; Gordon, John D. M.; Galbraith, John K.

    2012-03-01

    Basin-scale spatial and depth-related distribution patterns of deepwater demersal fishes were analysed using bottom trawl datasets from the North Atlantic continental margin, slopes of oceanic islands and seamounts, and the mid-Atlantic Ridge. Depth-stratified presence-absence data for 593 species were compiled from fisheries-independent trawl studies with full species lists. The datasets comprised trawls conducted on the upper continental slope (200 m) to abyssal depths, and 750 m wide depth strata were used. Number of species and families declined with depth in all areas. Species number was highest in the western North Atlantic, significantly lower on the mid-Atlantic Ridge and eastern North Atlantic. Observed species numbers are also low in southern areas (Bahamas, NW Africa, southerly seamounts), but the sampling effort in these waters has been much less than in northern sites. Fish assemblages vary by depth, latitude and longitude, and the study corroborates earlier suggestions that assemblages are broadly distributed in relation to regional circulation and watermass features. The mid-Atlantic Ridge assemblages between Iceland and the Azores are most similar to those on eastern North Atlantic slopes and rises, rather dissimilar to all others, including western Atlantic, Greenland, northwest Africa and Azorean seamount and island assemblages. Across the North Atlantic differences between subareas are strongest at slope depths, much less pronounced at the less speciose rise and abyssal depths. Demersal fish biomass estimates suggest that the American slope (New England) has low biomass compared with Newfoundland and European areas, and that the supposedly oligotrophic mid-Atlantic Ridge has a level of biomass similar to or higher than the European margin.

  18. Fracture zones in the equatorial Atlantic and the breakup of western Pangea

    SciTech Connect

    Jones, E.J.W.

    1987-06-01

    The early breakup of western Pangea has been investigated by mapping the pattern of fracture zones and distribution of seismic reflectors within the sedimentary cover of the Atlantic between the Cape Verde Islands and the equator. Two distinct sets of transverse oceanic lineaments are present, separated by the Guinea Fracture Zone near lat 10/sup 0/N. Lineaments to the north are associated with the formation of the central Atlantic in the Late Jurassic and Early Cretaceous; those in the south relate to the Cretaceous opening of the South Atlantic. The Guinea Fracture Zone is thus the conjugate of the Jurassic transform boundary under peninsular Florida, which linked the Atlantic with the Gulf of Mexico. The distribution of dated seismic reflectors suggests that deposition of deep-water sediments was confined to the region north of the Guinea transform until Aptian time, when the Sierra Leone Basin began to open. The latter started to widen at least 15 m.y. after the initiation of the Cape Basin off southwest Africa, an age difference that can be explained if a short-lived plate boundary developed in either Africa or South America during the Early Cretaceous. Neither the trends of the equatorial fracture zones nor the seismic stratigraphy supports the existence of a predrift gap between west Africa and Brazil.

  19. 78 FR 34879 - Special Local Regulations for Marine Events, Atlantic City Offshore Race, Atlantic Ocean...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-11

    ... City Offshore Race, Atlantic Ocean; Atlantic City, NJ AGENCY: Coast Guard, DHS. ACTION: Temporary final... to only one recurring marine event, held on the Atlantic Ocean, offshore of Atlantic City, New Jersey... Atlantic Ocean near Atlantic City, New Jersey, during the event. DATES: This rule will be effective on...

  20. Arctic Vortex changes alter the sources and isotopic values of precipitation in northeastern US.

    PubMed

    Puntsag, Tamir; Mitchell, Myron J; Campbell, John L; Klein, Eric S; Likens, Gene E; Welker, Jeffrey M

    2016-01-01

    Altered atmospheric circulation, reductions in Arctic sea ice, ocean warming, and changes in evaporation and transpiration are driving changes in the global hydrologic cycle. Precipitation isotopic (δ(18)O and δ(2)H) measurements can help provide a mechanistic understanding of hydrologic change at global and regional scales. To study the changing water cycle in the northeastern US, we examined the longest (1968-2010) record of precipitation isotope values, collected at the Hubbard Brook Experimental Forest in New Hampshire, US (43(°)56'N, 71(°)45'W). We found a significant reduction in δ(18)O and δ(2)H values over the 43-year record, coupled with a significant increase in d-excess values. This gradual reduction in δ(18)O and δ(2)H values unexpectedly occurred during a period of regional warming. We provide evidence that these changes are governed by the interactions among the Atlantic Multidecadal Oscillation, loss of Arctic sea ice, the fluctuating jet stream, and regular incursions of polar air into the northeastern US. PMID:26971874

  1. Migration patterns and wintering range of common loons breeding in the Northeastern United States

    USGS Publications Warehouse

    Kenow, K.P.; Adams, D.; Schoch, N.; Evers, D.C.; Hanson, W.; Yates, D.; Savoy, L.; Fox, T.J.; Major, A.; Kratt, R.; Ozard, J.

    2009-01-01

    A study, using satellite telemetry, was conducted to determine the precise migration patterns and wintering locations of Common Loons (Gavia immer) breeding in the northeastern United States. Transmitters were implanted in 17 loons (16 adults and one juvenile) that were captured on breeding lakes in New York, New Hampshire, and Maine during the summers of 2003, 2004, and 2005. Transmitters from ten of the birds provided adequate location data to document movement to wintering areas. Most adult loons appeared to travel non-stop from breeding lakes, or neighboring lakes (within 15 km), to the Atlantic coast. Adult loons marked in New Hampshire and Maine wintered 152 to 239 km from breeding lakes, along the Maine coast. Adult loons marked in the Adirondack Park of New York wintered along the coasts of Massachusetts (414 km from breeding lake), Rhode Island (362 km), and southern New Jersey (527 km). Most of the loons remained relatively stationary throughout the winter, but the size of individual wintering areas of adult loons ranged from 43 to 1,159 km 2, based on a 95% fixed kernel utilization distribution probability. A juvenile bird from New York made a number of stops at lakes and reservoirs en route to Long Island Sound (325 km from breeding lake). Maximum functional life of transmitters was about 12 months, providing an opportunity to document spring migration movements as well. This work provides essential information for development and implementation of regional Common Loon conservation strategies in the Northeastern U.S.

  2. Arctic Vortex changes alter the sources and isotopic values of precipitation in northeastern US

    PubMed Central

    Puntsag, Tamir; Mitchell, Myron J.; Campbell, John L.; Klein, Eric S.; Likens, Gene E.; Welker, Jeffrey M.

    2016-01-01

    Altered atmospheric circulation, reductions in Arctic sea ice, ocean warming, and changes in evaporation and transpiration are driving changes in the global hydrologic cycle. Precipitation isotopic (δ18O and δ2H) measurements can help provide a mechanistic understanding of hydrologic change at global and regional scales. To study the changing water cycle in the northeastern US, we examined the longest (1968–2010) record of precipitation isotope values, collected at the Hubbard Brook Experimental Forest in New Hampshire, US (43o56′N, 71o45′W). We found a significant reduction in δ18O and δ2H values over the 43-year record, coupled with a significant increase in d-excess values. This gradual reduction in δ18O and δ2H values unexpectedly occurred during a period of regional warming. We provide evidence that these changes are governed by the interactions among the Atlantic Multidecadal Oscillation, loss of Arctic sea ice, the fluctuating jet stream, and regular incursions of polar air into the northeastern US. PMID:26971874

  3. Layered Atlantic Smoke Interactions with Clouds (LASIC) Science Plan

    SciTech Connect

    Zuidema, P; Chiu, C; Fairall, CW; Ghan, SJ; Kollias, P; McFarguhar, GM; Mechem, DB; Romps, DM; Wong, H; Yuter, SE; Alvarado, MJ; DeSzoeke, SP; Feingold, G; Haywood, JM; Lewis, ER; McComiskey, A; Redemann, J; Turner, DD; Wood, R; Zhu, P

    2015-12-01

    Southern Africa is the world’s largest emitter of biomass-burning (BB) aerosols. Their westward transport over the remote southeast Atlantic Ocean colocates some of the largest atmospheric loadings of absorbing aerosol with the least examined of the Earth’s major subtropical stratocumulus decks. Global aerosol model results highlight that the largest positive top-of-atmosphere forcing in the world occurs in the southeast Atlantic, but this region exhibits large differences in magnitude and sign between reputable models, in part because of high variability in the underlying model cloud distributions. Many uncertainties contribute to the highly variable model radiation fields: the aging of shortwave-absorbing aerosol during transport, how much of the aerosol mixes into the cloudy boundary layer, and how the low clouds adjust to smoke-radiation and smoke-cloud interactions. In addition, the ability of the BB aerosol to absorb shortwave radiation is known to vary seasonally as the fuel type on land changes.

  4. Early Triassic geologic history of northeastern Nevada

    SciTech Connect

    Paull, R.K.; Paull, R.A.

    1986-08-01

    Conodont biostratigraphic and lithostratigraphic studies of Lower Triassic rocks in northeastern Elko County, Nevada, and adjacent parts of Idaho and Utah provide new information about regional geologic history. A sequential summary of Early Triassic events in this area follows: (1) rapid transgression of the Griesbachian sea to limiting barriers on the south (Oquirrh-Uinta axis) and west (Humboldt highland.). (2) Although the initial Triassic transgression may have persisted farther south and west than present-day evidence indicates, a period of progradation during the Dienerian limited marine sedimentation to northeastern-most Nevada and adjacent states. (3) In Smithian time, a widespread transgression spilled south and west over the earliest Triassic basin margin. (4) The southward flood is characterized by locally spectacular basal conglomerates followed by shallow marine deposits of the Thaynes Formation. (5) The transgression to the west was facilitated by tectonic removal of the restrictive barrier during the Smithian. This resulted in a slope-basin environment that accumulated a thick sequence of shale and calcareous siltstone with interbeds of turbidite conglomerates, olistostromes, and exotic blocks derived from Permian formations in northern Nevada or adjacent Idaho. (6) During a regional progradation in early Spathian time, marine conditions persisted in northeastern Nevada. (7) A final depositional episode is documented by the progressive westward spread of carbonate rocks of the Thaynes Formation. (8) Withdrawal of Triassic seas from northeast Nevada occurred post-latest Early Triassic, since a carbonate sequence of more than 300 m overlies the youngest dated interval.

  5. Generation 2030/Africa

    ERIC Educational Resources Information Center

    You, Danzhen; Hug, Lucia; Anthony, David

    2014-01-01

    Until relatively recently, much of Africa has been among the economically least developed and least densely populated places on earth, replete with villages and rural communities. Africa is changing rapidly, in its economy, trade and investment; in climate change; in conflict and stability; in urbanization, migration patterns, and most of all in…

  6. Teaching about Francophone Africa.

    ERIC Educational Resources Information Center

    Merryfield, Mary; Timbo, Adama

    Lessons and resources for Social Studies and French courses are included in this document. The major goals of these materials are to help students (1) explore the history and geography of Francophone Africa, (2) examine French influences in contemporary Africa, (3) recognize and appreciate cultural differences and similarities in values and…

  7. Language in South Africa.

    ERIC Educational Resources Information Center

    Mesthrie, Rajend, Ed.

    This collection of 24 papers focuses on language and society in South Africa. Part 1, "The Main Language Groupings," includes (1) "South Africa: A Sociolinguistic Overview" (R. Mesthrie); (2) "The Khoesan Languages" (A. Traill); (3) "The Bantu Languages: Sociohistorical Perspectives" (Robert K. Herbert and Richard Bailey); (4) "Afrikaans:…

  8. Historical Capsule: South Africa.

    ERIC Educational Resources Information Center

    Cole, Robert

    1988-01-01

    Briefly traces the history of South Africa from British acquisition in 1815 through the creation of the Union of South Africa in 1910. Presents a chronicle of the year 1900 to show part of the European achievement in close-up. Lists accomplishments in literature, fine arts, science, technology, music, theater, and dance. (GEA)

  9. Multilingualism in Southern Africa.

    ERIC Educational Resources Information Center

    Peirce, Bonny Norton; Ridge, Stanley G. M.

    1997-01-01

    Reviews recent research in multilingualism in Southern Africa, focusing on the role of languages in education, sociolinguistics, and language policy. Much of the research is on South Africa. Topics discussed include language of instruction in schools, teacher education, higher education, adult literacy, language contact, gender and linguistic…

  10. Reconstruction of Major Atlantic Hurricane Activity Back To 1750

    NASA Astrophysics Data System (ADS)

    Nyberg, J.; Malmgren, B. A.

    A reconstruction is presented of major hurricane activity in the Atlantic region back to 1750. Almost all Atlantic major hurricanes (> 50 m/s; categories 3, 4, or 5 on the Saffir-Simpson hurricane scale) are developed in the area westward of Africa across the tropical Atlantic and Caribbean Sea at latitudes between 10N and 20N; an area termed the Main Development Region (MDR). They are developed through atmo- spheric easterly waves that propagate westward from Africa across the tropical North Atlantic. The magnitude of the vertical shear of the horizontal winds between the lower and upper troposphere |Vz| during August to October together with sea-surface temperatures (SSTs) in the MDR are the dominant factors controlling major hurricane activity. Local vertical wind shear |Vz| of > 8 m/s is unfavourable for development of major hurricanes due to prevention of the axisymmetric organisation of deep convec- tion. Local SSTs play a direct role in providing moist enthalpy to incipient hurricanes. Two proxies of tradewind variability from the Caribbean Sea derived from lumines- cence intensity in a coral core and abundance of the planktonic foraminifer Globige- rina bulloides in a sediment core, which are strongly correlated with |Vz| in MDR and major hurricane activity back to 1949 and 1944, respectively, are together with records of SSTs used to reconstruct major hurricane activity. The reconstruction indicates that the time interval from the late 1960s to early 1990s may have experienced strong |Vz| and few major hurricanes compared to other periods since 1750.

  11. What controls early or late onset of tropical North Atlantic hurricane season?

    NASA Astrophysics Data System (ADS)

    Zuo, Heng; Li, Tim; Liu, Jia; Peng, Melinda

    2016-06-01

    The occurrence of first hurricane in early summer signifies the onset of an active Atlantic hurricane season. The interannual variation of this hurricane onset date is examined for the period 1979-2013. It is found that the onset date has a marked interannual variation. The standard deviation of the interannual variation of the onset day is 17.5 days, with the climatological mean onset happening on July 23. A diagnosis of tropical cyclone (TC) genesis potential index (GPI) indicates that the major difference between an early and a late onset group lies in the maximum potential intensity (MPI). A further diagnosis of the MPI shows that it is primarily controlled by the local SST anomaly (SSTA). Besides the SSTA, vertical shear and mid-tropospheric relative humidity anomalies also contribute significantly to the GPI difference between the early and late onset groups. It is found that the anomalous warm (cold) SST over the tropical Atlantic, while uncorrelated with the Niño3 index, persists from the preceding winter to concurrent summer in the early (late) onset group. The net surface heat flux anomaly always tends to damp the SSTA, which suggests that ocean dynamics may play a role in maintaining the SSTA in the tropical Atlantic. The SSTA pattern with a maximum center in northeastern tropical Atlantic appears responsible for generating the observed wind and moisture anomalies over the main TC development region. A further study is needed to understand the initiation mechanism of the SSTA in the Atlantic.

  12. Contextual view showing northeastern eucalyptus windbreak and portion of citrus ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Contextual view showing northeastern eucalyptus windbreak and portion of citrus orchard. Camera facing 118" east-southeast. - Goerlitz House, 9893 Highland Avenue, Rancho Cucamonga, San Bernardino County, CA

  13. Magnetotactic bacteria population in a pristine French Atlantic lagoon.

    PubMed

    Pradel, Nathalie; Fuduche, Maxime; Ollivier, Bernard

    2016-01-01

    In this study, we report for the first time the presence of magnetotactic bacteria (MTB) on the Northeastern Atlantic coast. Microscopy observations indicated a heterogeneous population of MTB morphotypes. The analysis of the 16S rDNA by pyrosequencing technology revealed four operational taxonomic sequence units affiliated within the Magnetococcales order, class Alphaproteobacteria. One of them was closely related to sequences of MTB from the Tunisian coast, central Mediterranean Sea. This work offers information on anew environmental context and on biogeography of MTB, highlights the putative impact that marine currents may have on MTB distribution on Earth, and underlines the role that pristine or polluted areas may play on the structure of the MTB communites.

  14. An investigation of Ekman upwelling in the North Atlantic

    NASA Technical Reports Server (NTRS)

    Mcclain, Charles R.; Firestone, James

    1993-01-01

    The spatial and temporal variability of the North Atlantic Ekman upwelling fields on seasonal and interannual time scales is investigated on the basis of surface winds from the Fleet Numerical Oceanography Center for 1979-1986. A pronounced minimum in the basin-wide monthly mean vertical Ekman velocities during 1981-1982 is found. It is shown that the primary source of the interannual signal was the region off NW Africa in the vicinity of the Guinea Dome. Other sectors of the basin experienced no significant interannual trends. Hydrographic data and SST data from the NW Africa sector for 1981-1986 indicate a cooling trend beginning in late 1982, consistent with increased upwelling. The fall and winter seasons' mixed layers at the center of the Guinea Dome were deeper in 1984 and 1985 than in previous years. The potential impact of large interannual variations in Ekman upwelling on basin-wide primary productivity is discussed.

  15. Two Distinct Roles of Atlantic SSTs in ENSO Variability: North Tropical Atlantic SST and Atlantic Nino

    NASA Technical Reports Server (NTRS)

    Ham, Yoo-Geun; Kug, Jong-Seong; Park, Jong-Yeon

    2013-01-01

    Two distinct roles of the Atlantic sea surface temperatures (SSTs), namely, the North Tropical Atlantic (NTA) SST and the Atlantic Nino, on the El Nino-Southern Oscillation (ENSO) variability are investigated using the observational data from 1980 to 2010 and coupled model experiments. It appears that the NTA SST and the Atlantic Nino can be used as two independent predictors for predicting the development of ENSO events in the following season. Furthermore, they are likely to be linked to different types of El Nino events. Specifically, the NTA SST cooling during February, March, and April contributes to the central Pacific warming at the subsequent winter season, while the negative Atlantic Nino event during June, July, and August contributes to enhancing the eastern Pacific warming. The coupled model experiments support these results. With the aid of a lagged inverse relationship, the statistical forecast using two Atlantic indices can successfully predict various ENSO indices.

  16. Safe water for Africa (Africa-1000)

    SciTech Connect

    Dalton, R.; Kashkari, C.

    1996-12-31

    Africa-1000 is a program to provide safe water to thousands of villages in Africa. It is a formidable effort and needs the support of the international scientific community. Science and technology is the only hope for a solution of the African crisis. There are vast areas in the Sub-Saharan Africa that have water under the ground but due to lack of electric power, the water cannot be pumped. Thus the land is dry and barren and people are starving. The African continent has abundant renewable energy in the form of solar and wind energy. The technologies are well developed and available in the developed countries. Therefore, the solution is as follows: dig and drill wells and boreholes to reach underground water; install standardized solar or wind driven pumps to bring water to the surface; train village technicians to operate, maintain and repair these energy systems; and replicate these installations in thousands of villages, thus establishing standard water and energy systems across Africa.

  17. Long-Term Simulation of Dust Distribution with the GOCART Model: Correlation with the North Atlantic Oscillation

    NASA Technical Reports Server (NTRS)

    Ginoux, P.; Prospero, J.; Torres, O.; Chin, M.

    2002-01-01

    Global distribution of aeolian dust is simulated from 1981 to 1996 with the Goddard Ozone Chemistry Aerosol Radiation and Transport (GOCART) model. The results are assessed with in-situ measurements and the Total Ozone Mapping Spectrometer (TOMS) aerosol products. The annual budget over the different continents and oceans are analyzed. It is found that there is a maximum of 25% difference of global annual emission from the minimum in 1996 to the maximum in 1988. There is a downward trend of dust emission over Africa and East Asia, of 6 and 2 Tg/yr, respectively. The inter-annual variability of dust distribution is analyzed over the North Atlantic and Africa. It is found that in winter most of the North Atlantic and Africa dust loading is correlated with the North Atlantic Oscillation. The GOCART model indicates that a controlling factor of such correlation can be attributed to dust emission from the Sahel. The Bodele depression is the major dust source in winter and its inter-annual variability is highly correlated with the NAO. However, it is not possible to conclude without further analysis that the North Atlantic Oscillation is forcing the inter-annual variability of dust emission and in-turn dust concentration over the North Atlantic.

  18. A benthic foraminiferal record of middle to late Pliocene (3.15-2.85 Ma) deep water change in the North Atlantic

    USGS Publications Warehouse

    Ishman, S.E.

    1996-01-01

    Records of benthic foraminifera from North Atlantic DSDP Site 607 and Hole 610A indicate changes in deep water conditions through the middle to late Pliocene (3.15 to 2.85 Ma). Quantitative analyses of modern associations in the North Atlantic indicate that seven species, Fontbotia wuellerstorfi, Cibicidoides kullenbergi, Uvigerina peregrina, Nuttallides umboniferus, Melonis pompilioides, Globocassidulina subglobosa and Epistominella exigua are useful for paleoenvironmental interpretation. The western North Atlantic basin (Site 607) was occupied by North Atlantic Deep Water (NADW) until ???2.88 Ma. At that time, N. umboniferus increased, indicating an influx of Southern Ocean Water (SOW). The eastern North Atlantic basin (Hole 610A) was occupied by a relatively warm water mass, possibly Northeastern Atlantic Deep Water (NEADW), through ???2.94 Ma when SOW more strongly influenced the site. These interpretations are consistent with benthic ??18O and ??13C records from 607 and 610A (Raymo et al., 1992). The results presented in this paper suggest that the North Atlantic was strongly influenced by northern component deep water circulation until 2.90-2.95 Ma. After that there was a transition toward a glacially driven North Atlantic circulation more strongly influenced by SOW associated with the onset of Northern Hemisphere glaciation. The circulation change follows the last significant SST and atmospheric warming prior to ???2.6 Ma.

  19. Do West African thunderstorms predict the intensity of Atlantic hurricanes?

    NASA Astrophysics Data System (ADS)

    Price, Colin; Reicher, Naama; Yair, Yoav

    2015-04-01

    Since 85% of all major Atlantic hurricanes originate as thunderstorm clusters in equatorial Africa, we have investigated the connection between these African thunderstorms and the consequent development of these disturbances into tropical storms. We have analyzed Meteosat infrared cloud top temperature data to determine the areal coverage of cold cloud tops over a 6 year period from 2005 to 2010. In addition, hurricane statistics from the same period (intensity, date of generation, location, and maximum winds) were obtained from the National Hurricane Center database. We first show that the areal coverage of cold clouds (with brightness temperatures Tb < -50°C) in tropical Africa is a good indicator of the monthly number of African Easterly Waves (AEWs) leaving the west coast of tropical Africa. Furthermore, the AEWs that develop into tropical storms have a significantly larger area covered by cold cloud tops compared with nondeveloping waves. Finally, we show that on a storm-by-storm basis, the cold cloud coverage in West Africa is positively correlated (r = 0.57) with the accumulated cyclone energy of the future tropical cyclones that develop out of these waves.

  20. Do West African Thunderstorms Predict the Intensity of Atlantic Hurricanes?

    NASA Astrophysics Data System (ADS)

    Price, Colin; Reicher, Naama; Yair, Yoav

    2015-04-01

    Since 85% of all major Atlantic hurricanes originate as thunderstorm clusters in equatorial Africa, we have investigated the connection between these African thunderstorms and the consequent development of these disturbances into tropical storms. We have analyzed METEOSAT infrared cloud-top temperature data to determine the areal coverage of cold cloud tops over a six year period from 2005-2010. In addition, hurricane statistics from the same period (intensity, date of generation, location, maximum winds) were obtained from the National Hurricane Center (NHC) data base. We first show that the areal coverage of cold clouds (with brightness temperatures Tb<-50oC) in tropical Africa is a good indicator of the monthly number of African Easterly Waves (AEWs) leaving the west coast of tropical Africa. Furthermore, the AEWs that develop into tropical storms have a significantly larger area covered by cold cloud tops compared with non-developing waves. Finally, we show that on a storm-by-storm basis, the cold cloud coverage in West Africa is positively correlated (r=0.57) with the accumulated cyclone energy (ACE) of the future tropical cyclones that develop out of these waves.

  1. Wet periods in northeastern Brazil over the past 210 kyr linked to distant climate anomalies.

    PubMed

    Wang, Xianfeng; Auler, Augusto S; Edwards, R Lawrence; Cheng, Hai; Cristalli, Patricia S; Smart, Peter L; Richards, David A; Shen, Chuan-Chou

    2004-12-01

    The tropics are the main source of the atmosphere's sensible and latent heat, and water vapour, and are therefore important for reconstructions of past climate. But long, accurately dated records of southern tropical palaeoclimate, which would allow the establishment of climatic connections to distant regions, have not been available. Here we present a 210,000-year (210-kyr) record of wet periods in tropical northeastern Brazil--a region that is currently semi-arid. The record is obtained from speleothems and travertine deposits that are accurately dated using the U/Th method. We find wet periods that are synchronous with periods of weak East Asian summer monsoons, cold periods in Greenland, Heinrich events in the North Atlantic and periods of decreased river runoff to the Cariaco basin. We infer that the wet periods may be explained with a southward displacement of the Intertropical Convergence Zone. This widespread synchroneity of climate anomalies suggests a relatively rapid global reorganization of the ocean-atmosphere system. We conclude that the wet periods probably affected rainforest distribution, as plant fossils show that forest expansion occurred during these intermittent wet intervals, and opened a forest corridor between the Amazonian and Atlantic rainforests. PMID:15592409

  2. Structure and Dynamics of the Shark Assemblage off Recife, Northeastern Brazil

    PubMed Central

    Afonso, André S.; Andrade, Humber A.; Hazin, Fábio H. V.

    2014-01-01

    Understanding the ecological factors that regulate elasmobranch abundance in nearshore waters is essential to effectively manage coastal ecosystems and promote conservation. However, little is known about elasmobranch populations in the western South Atlantic Ocean. An 8-year, standardized longline and drumline survey conducted in nearshore waters off Recife, northeastern Brazil, allowed us to describe the shark assemblage and to monitor abundance dynamics using zero-inflated generalized additive models. This region is mostly used by several carcharhinids and one ginglymostomid, but sphyrnids are also present. Blacknose sharks, Carcharhinus acronotus, were mostly mature individuals and declined in abundance throughout the survey, contrasting with nurse sharks, Ginglymostoma cirratum, which proliferated possibly due to this species being prohibited from all harvest since 2004 in this region. Tiger sharks, Galeocerdo cuvier, were mostly juveniles smaller than 200 cm and seem to use nearshore waters off Recife between January and September. No long-term trend in tiger shark abundance was discernible. Spatial distribution was similar in true coastal species (i.e. blacknose and nurse sharks) whereas tiger sharks were most abundant at the middle continental shelf. The sea surface temperature, tidal amplitude, wind direction, water turbidity, and pluviosity were all selected to predict shark abundance off Recife. Interspecific variability in abundance dynamics across spatiotemporal and environmental gradients suggest that the ecological processes regulating shark abundance are generally independent between species, which could add complexity to multi-species fisheries management frameworks. Yet, further research is warranted to ascertain trends at population levels in the South Atlantic Ocean. PMID:25010514

  3. Structure and dynamics of the shark assemblage off Recife, Northeastern Brazil.

    PubMed

    Afonso, André S; Andrade, Humber A; Hazin, Fábio H V

    2014-01-01

    Understanding the ecological factors that regulate elasmobranch abundance in nearshore waters is essential to effectively manage coastal ecosystems and promote conservation. However, little is known about elasmobranch populations in the western South Atlantic Ocean. An 8-year, standardized longline and drumline survey conducted in nearshore waters off Recife, northeastern Brazil, allowed us to describe the shark assemblage and to monitor abundance dynamics using zero-inflated generalized additive models. This region is mostly used by several carcharhinids and one ginglymostomid, but sphyrnids are also present. Blacknose sharks, Carcharhinus acronotus, were mostly mature individuals and declined in abundance throughout the survey, contrasting with nurse sharks, Ginglymostoma cirratum, which proliferated possibly due to this species being prohibited from all harvest since 2004 in this region. Tiger sharks, Galeocerdo cuvier, were mostly juveniles smaller than 200 cm and seem to use nearshore waters off Recife between January and September. No long-term trend in tiger shark abundance was discernible. Spatial distribution was similar in true coastal species (i.e. blacknose and nurse sharks) whereas tiger sharks were most abundant at the middle continental shelf. The sea surface temperature, tidal amplitude, wind direction, water turbidity, and pluviosity were all selected to predict shark abundance off Recife. Interspecific variability in abundance dynamics across spatiotemporal and environmental gradients suggest that the ecological processes regulating shark abundance are generally independent between species, which could add complexity to multi-species fisheries management frameworks. Yet, further research is warranted to ascertain trends at population levels in the South Atlantic Ocean.

  4. Structure and dynamics of the shark assemblage off Recife, Northeastern Brazil.

    PubMed

    Afonso, André S; Andrade, Humber A; Hazin, Fábio H V

    2014-01-01

    Understanding the ecological factors that regulate elasmobranch abundance in nearshore waters is essential to effectively manage coastal ecosystems and promote conservation. However, little is known about elasmobranch populations in the western South Atlantic Ocean. An 8-year, standardized longline and drumline survey conducted in nearshore waters off Recife, northeastern Brazil, allowed us to describe the shark assemblage and to monitor abundance dynamics using zero-inflated generalized additive models. This region is mostly used by several carcharhinids and one ginglymostomid, but sphyrnids are also present. Blacknose sharks, Carcharhinus acronotus, were mostly mature individuals and declined in abundance throughout the survey, contrasting with nurse sharks, Ginglymostoma cirratum, which proliferated possibly due to this species being prohibited from all harvest since 2004 in this region. Tiger sharks, Galeocerdo cuvier, were mostly juveniles smaller than 200 cm and seem to use nearshore waters off Recife between January and September. No long-term trend in tiger shark abundance was discernible. Spatial distribution was similar in true coastal species (i.e. blacknose and nurse sharks) whereas tiger sharks were most abundant at the middle continental shelf. The sea surface temperature, tidal amplitude, wind direction, water turbidity, and pluviosity were all selected to predict shark abundance off Recife. Interspecific variability in abundance dynamics across spatiotemporal and environmental gradients suggest that the ecological processes regulating shark abundance are generally independent between species, which could add complexity to multi-species fisheries management frameworks. Yet, further research is warranted to ascertain trends at population levels in the South Atlantic Ocean. PMID:25010514

  5. Interannual variability of tropical cyclone activity and regional Hadley circulation over the Northeastern Pacific

    NASA Astrophysics Data System (ADS)

    Zhang, Gan; Wang, Zhuo

    2015-04-01

    The interannual variability of the regional Hadley circulation (HC) and tropical cyclone (TC) activity over the Northeastern Pacific (NEP) was investigated. The interannual variability of the HC in the NEP hurricane season is found dominated by a mode (M1EP) regulating the strength and meridional extent of the Intertropical Convergence Zone. M1EP has a more robust correlation with NEP TC activity than the El Niño-Southern Oscillation sea surface temperature indices. The strong correlation is attributed to the impacts of M1EP on environmental conditions. In addition, the leading mode of the Atlantic HC, which has an anticorrelation with M1EP, also strongly impacts NEP TC activity. The findings, together with Zhang and Wang (2013), highlight the role of the HC in controlling the variability of TC activity as well as the interbasin connection between the NEP and the Atlantic. The regional HC is thus recommended as a useful metric to benchmark models in simulating TC activity.

  6. Wet periods in northeastern Brazil over the past 210 kyr linked to distant climate anomalies.

    PubMed

    Wang, Xianfeng; Auler, Augusto S; Edwards, R Lawrence; Cheng, Hai; Cristalli, Patricia S; Smart, Peter L; Richards, David A; Shen, Chuan-Chou

    2004-12-01

    The tropics are the main source of the atmosphere's sensible and latent heat, and water vapour, and are therefore important for reconstructions of past climate. But long, accurately dated records of southern tropical palaeoclimate, which would allow the establishment of climatic connections to distant regions, have not been available. Here we present a 210,000-year (210-kyr) record of wet periods in tropical northeastern Brazil--a region that is currently semi-arid. The record is obtained from speleothems and travertine deposits that are accurately dated using the U/Th method. We find wet periods that are synchronous with periods of weak East Asian summer monsoons, cold periods in Greenland, Heinrich events in the North Atlantic and periods of decreased river runoff to the Cariaco basin. We infer that the wet periods may be explained with a southward displacement of the Intertropical Convergence Zone. This widespread synchroneity of climate anomalies suggests a relatively rapid global reorganization of the ocean-atmosphere system. We conclude that the wet periods probably affected rainforest distribution, as plant fossils show that forest expansion occurred during these intermittent wet intervals, and opened a forest corridor between the Amazonian and Atlantic rainforests.

  7. Poverty reduction in Africa

    PubMed Central

    Collier, Paul

    2007-01-01

    Poverty in Africa has been rising for the last quarter-century, while it has been falling in the rest of the developing world. Africa's distinctive problem is that its economies have not been growing. This article attempts to synthesize a range of recent research to account for this failure of the growth process. I argue that the reasons lie not in African peculiarities but rather in geographic features that globally cause problems but that are disproportionately pronounced in Africa. These features interact to create three distinct challenges that are likely to require international interventions beyond the conventional reliance on aid. PMID:17942702

  8. Livestock First Reached Southern Africa in Two Separate Events

    PubMed Central

    Sadr, Karim

    2015-01-01

    After several decades of research on the subject, we now know when the first livestock reached southern Africa but the question of how they got there remains a contentious topic. Debate centres on whether they were brought with a large migration of Khoe-speakers who originated from East Africa; or whether the livestock were traded down-the-line among hunter-gatherer communities; or indeed whether there was a long history of diverse small scale population movements in this part of the world, one or more of which ‘infiltrated’ livestock into southern Africa. A new analysis of the distribution of stone toolkits from a sizeable sample of sub-equatorial African Later Stone Age sites, coupled with existing knowledge of the distribution of the earliest livestock remains and ceramics vessels, has allowed us to isolate two separate infiltration events that brought the first livestock into southern Africa just over 2000 years ago; one infiltration was along the Atlantic seaboard and another entered the middle reaches of the Limpopo River Basin. These findings agree well with the latest results of genetic research which together indicate that multiple, small-scale infiltrations probably were responsible for bringing the first livestock into southern Africa. PMID:26295347

  9. Livestock First Reached Southern Africa in Two Separate Events.

    PubMed

    Sadr, Karim

    2015-01-01

    After several decades of research on the subject, we now know when the first livestock reached southern Africa but the question of how they got there remains a contentious topic. Debate centres on whether they were brought with a large migration of Khoe-speakers who originated from East Africa; or whether the livestock were traded down-the-line among hunter-gatherer communities; or indeed whether there was a long history of diverse small scale population movements in this part of the world, one or more of which 'infiltrated' livestock into southern Africa. A new analysis of the distribution of stone toolkits from a sizeable sample of sub-equatorial African Later Stone Age sites, coupled with existing knowledge of the distribution of the earliest livestock remains and ceramics vessels, has allowed us to isolate two separate infiltration events that brought the first livestock into southern Africa just over 2000 years ago; one infiltration was along the Atlantic seaboard and another entered the middle reaches of the Limpopo River Basin. These findings agree well with the latest results of genetic research which together indicate that multiple, small-scale infiltrations probably were responsible for bringing the first livestock into southern Africa.

  10. Multiproxy (pollen, stable isotopes, trace elements) reconstruction of climate variability in northeastern Amazon during the late Holocene

    NASA Astrophysics Data System (ADS)

    Conte, M. H.; Urrego, D. H.; Charles-Dominique, P.; Giraudeau, J.; Martinez, P.; Bush, M. B.; Huang, Y.; Russell, J. M.; Gaucher, P.

    2013-12-01

    Model projections of future climate predict changes in ocean-atmosphere processes that will affect the organization of the Atlantic Intertropical Convergence Zone (ITCZ) and ENSO, and in turn, precipitation patterns over much of South America. The northeastern Amazon is particularly sensitive to ITCZ and ENSO organization, and experiences major episodes of drought and rainfall extremes due to interannual variability in ITCZ intensity and position. Hence understanding Holocene climate variability in the northeastern Amazon, and its phasing with other South American records, can provides new insights into past ITCZ organization and Atlantic-Pacific teleconnections. Lac Toponowini is a landslide-dammed lake in the undisturbed highland rainforest of French Guiana (Guyane). Toponowini sediments are finely varved, with pronounced light-dark couplets that appear to reflect alternating wet and dry season conditions. High-resolution X-Ray Fluorescence (XRF) profiling reveals that the couplets consist of bands of weathered clays and organic-rich material containing co-precipitated sulfides and platinum group elements (PGEs), sourced from gold deposits in the watershed. Mobility of PGEs is highly sensitive to hydrology and groundwater chemistry, and subtle variations in PGE flux and composition in Lac Toponowini appears to track past hydrologic conditions. Of note is the inverse correlation between the Pd/Pb ratio in Toponowini sediments and the %Ti record of fluvial input into the Cariaco Basin (Peterson and Haug 2006, Palaeogeog. Palaeoclim. Palaeoecol. 234, 97-113), which suggests antiphasing between rainfall in northern South America and French Guiana, consistent with ITCZ migration forced by multidecadal Atlantic variability. The carbon isotopic composition (δ13C) of terrestrial leaf waxes exhibits a maximum at ~1500 years BP, consistent with pollen evidence (Ledru 2001, Rev. Paleobot. Palynol. 115, 161-176) for ecosystem adaptations indicative of drier conditions in

  11. A new genus and a new species of Sminthuridae (Collembola: Symphypleona) from Atlantic Forest of Brazil.

    PubMed

    Da Silva, Diego Dias; Palacios-Vargas, José G; Bellini, Bruno Cavalcante

    2015-01-01

    Sminthuridae comprises approximately 240 species distributed worldwide. In Brazil it is represented only by 11 species and four genera. Herein we describe a new genus and species of subfamily Sminthurinae from Atlantic Forest of Rio Grande do Norte State, Northeastern Brazil. The new described genus is similar to Gisinurus, Songhaica, Dietersminthurus and Soqotrasminthurus, especially in its unguis shape, with open cavity; but differs from all other genera of Sminthuridae by the presence of a single pretarsal chaeta in anterior side, smooth mucronal edges and a unique head chaetotaxy. PMID:26250241

  12. Impacts of Low-Flow and Stream-Temperature Changes on Endangered Atlantic Salmon - Current Research

    USGS Publications Warehouse

    Dudley, Robert W.; Hodgkins, Glenn A.; Letcher, Benjamin H.

    2008-01-01

    Recent climate studies in New England and the northeastern United States have shown evidence of physical changes over time, including trends toward earlier snowmelt runoff, decreasing river ice, and increasing spring water temperatures. A U.S. Geological Survey (USGS) study funded by the National Global Warming and Wildlife Science Center will be investigating changes in summer low streamflows and stream temperatures and the potential effects of those changes on endangered Atlantic salmon populations. The study also will evaluate management options that would be most likely to mitigate the effects of any changes in streamflow and temperature.

  13. A new genus and a new species of Sminthuridae (Collembola: Symphypleona) from Atlantic Forest of Brazil.

    PubMed

    Da Silva, Diego Dias; Palacios-Vargas, José G; Bellini, Bruno Cavalcante

    2015-07-27

    Sminthuridae comprises approximately 240 species distributed worldwide. In Brazil it is represented only by 11 species and four genera. Herein we describe a new genus and species of subfamily Sminthurinae from Atlantic Forest of Rio Grande do Norte State, Northeastern Brazil. The new described genus is similar to Gisinurus, Songhaica, Dietersminthurus and Soqotrasminthurus, especially in its unguis shape, with open cavity; but differs from all other genera of Sminthuridae by the presence of a single pretarsal chaeta in anterior side, smooth mucronal edges and a unique head chaetotaxy.

  14. Barriers to Gene Flow in the Marine Environment: Insights from Two Common Intertidal Limpet Species of the Atlantic and Mediterranean

    PubMed Central

    Sá-Pinto, Alexandra; Branco, Madalena S.; Alexandrino, Paulo B.; Fontaine, Michaël C.; Baird, Stuart J. E.

    2012-01-01

    Knowledge of the scale of dispersal and the mechanisms governing gene flow in marine environments remains fragmentary despite being essential for understanding evolution of marine biota and to design management plans. We use the limpets Patella ulyssiponensis and Patella rustica as models for identifying factors affecting gene flow in marine organisms across the North-East Atlantic and the Mediterranean Sea. A set of allozyme loci and a fragment of the mitochondrial gene cytochrome C oxidase subunit I were screened for genetic variation through starch gel electrophoresis and DNA sequencing, respectively. An approach combining clustering algorithms with clinal analyses was used to test for the existence of barriers to gene flow and estimate their geographic location and abruptness. Sharp breaks in the genetic composition of individuals were observed in the transitions between the Atlantic and the Mediterranean and across southern Italian shores. An additional break within the Atlantic cluster separates samples from the Alboran Sea and Atlantic African shores from those of the Iberian Atlantic shores. The geographic congruence of the genetic breaks detected in these two limpet species strongly supports the existence of transpecific barriers to gene flow in the Mediterranean Sea and Northeastern Atlantic. This leads to testable hypotheses regarding factors restricting gene flow across the study area. PMID:23239977

  15. Barriers to gene flow in the marine environment: insights from two common intertidal limpet species of the Atlantic and Mediterranean.

    PubMed

    Sá-Pinto, Alexandra; Branco, Madalena S; Alexandrino, Paulo B; Fontaine, Michaël C; Baird, Stuart J E

    2012-01-01

    Knowledge of the scale of dispersal and the mechanisms governing gene flow in marine environments remains fragmentary despite being essential for understanding evolution of marine biota and to design management plans. We use the limpets Patella ulyssiponensis and Patella rustica as models for identifying factors affecting gene flow in marine organisms across the North-East Atlantic and the Mediterranean Sea. A set of allozyme loci and a fragment of the mitochondrial gene cytochrome C oxidase subunit I were screened for genetic variation through starch gel electrophoresis and DNA sequencing, respectively. An approach combining clustering algorithms with clinal analyses was used to test for the existence of barriers to gene flow and estimate their geographic location and abruptness. Sharp breaks in the genetic composition of individuals were observed in the transitions between the Atlantic and the Mediterranean and across southern Italian shores. An additional break within the Atlantic cluster separates samples from the Alboran Sea and Atlantic African shores from those of the Iberian Atlantic shores. The geographic congruence of the genetic breaks detected in these two limpet species strongly supports the existence of transpecific barriers to gene flow in the Mediterranean Sea and Northeastern Atlantic. This leads to testable hypotheses regarding factors restricting gene flow across the study area.

  16. View of northeastern Italy including Venice

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A near vertical view of northeastern Italy including the Venice (Venezia) area is seen in this Skylab 3 Earth Resources Experiments Package S190-B (five-inch earth terrain camera) infrared photograph taken from the Skylab space station in Earth orbit. The mountainous area is the Dolomite Alps. The most conspicuous stream northeast of Venice is the Piave River. The city near the center of the picture on the Brenta River is Bassano del Grappa. The large city of Padua (Padova) is on the western bank of the Grenta near the clock.

  17. Recent sedimentation, northeastern Port Valdez, Alaska

    NASA Astrophysics Data System (ADS)

    Palmer, Harold D.

    1981-09-01

    Sediments accumulating on the northeastern shore of Port Valdez, a fjord leading to Prince William Sound in southern Alaska, are derived from both deltaic and alluvial fan processes. The resulting thick wedge of Recent silts, sands, shells and gravels lies atop irregular ridges of local graywacke bedrock and scattered till deposits. Seismic reflection profiling augmented by soil borings indicates that rapid infilling and upbuilding has occurred at this site. Evidence of slumping suggests general instability of steep submarine slopes in an area characterized by strong earthquakes and large tidal ranges.

  18. Research Management in Africa.

    ERIC Educational Resources Information Center

    Benneh, George

    2002-01-01

    Examines research management, particularly within higher education institutions, in Africa including, research and current trends in knowledge production, institutional aspects, research funding, and good practice in research management. (EV)

  19. Women in Africa

    ERIC Educational Resources Information Center

    Spitzer, Manon

    1975-01-01

    The role and status of women in Africa has changed profoundly since the end of the colonial period. Many differences in women's status and role are based on geography, history, nationality, political and socioeconomic systems, culture, and religion. (JR)

  20. 78 FR 16573 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery and Northeast...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-15

    ... other considered alternatives and provides a thorough analysis of the impacts of the proposed measures... Analysis (IRFA), are available upon request from Paul J. Howard, Executive Director, New England Fishery... according to Amendment 11 to the Scallop FMP (Amendment 11; 72 FR 20090; April 14, 2008) fleet...

  1. 75 FR 65580 - Fisheries of the Northeastern United States; Atlantic Surfclam and Ocean Quahog Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-26

    ... than 4.75 inches (120 mm) and the overall reduced size is not attributable to harvest from beds where... were less than 4.75 inches (120 mm). Based on these data, the Regional Administrator adopts the...

  2. 75 FR 70187 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-17

    ... (75 FR 3092, January 19, 2010). The deadline for submission was March 22, 2010. The project selection... the Loligo fishery, established in 2010 by MSB Amendment 10 (75 FR 11441, March 11, 2010), could.... Section 648.26 as amended at 75 FR 11450, March 11, 2010, effective January 1, 2011, and is...

  3. 76 FR 47492 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fishery...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-05

    ... the interim rule published March 15, 2011 (76 FR 13887), is extended through March 16, 2012, unless... (76 FR 13887), as authorized by section 305(c) of the Magnuson-Stevens Act, to increase the butterfish... the MSB Fishery Management Plan (FMP) (76 FR 8306; February 14, 2011). There was one anonymous...

  4. 76 FR 45742 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-01

    ... multiple occasions since 1992, with the most recent control date set as July 5, 2002 (67 FR 44792, later reaffirmed on June 9, 2005, 70 FR 33728). The Council initially notified the public of its intent to consider...) on March 4, 2005 (70 FR 10605). The Council subsequently conducted scoping meetings in March 2005...

  5. 77 FR 51853 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-27

    ... Adjustment 6 on June 28, 2012 (77 FR 38566). Additional background information and detail on why and how... implemented Omnibus Amendment for Annual Catch Limits and Accountability Measures (October 31, 2011; 76 FR..., 2011; 76 FR 66260) with the Council's original 2012 butterfish ABC recommendation (3,622 mt)...

  6. 76 FR 68642 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-07

    ... Federal Register on August 1, 2011 (76 FR 45742), with comments accepted through September 15, 2011. The... Secretary on August 12, 2011, and published as a final rule on September 29, 2011 (76 FR 60606). Several... July 1, 2011 (76 FR 38650). The FEIS describes the impacts of the proposed Amendment 11 measures on...

  7. 75 FR 11441 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-11

    ... Amendment 10 was published on July 14, 2009 (74 FR 33986), with a comment period ending on September 14, 2009. A proposed rule for Amendment 10 was published on September 3, 2009 (74 FR 45597), with a comment... June 26, 2009; a notice of availability was published on July 2, 2009 (74 FR 31733). In...

  8. 77 FR 16472 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-21

    ... MSB specifications and management measures was published on October 26, 2011 (76 FR 66260), and the... Amendment (Omnibus Amendment; 76 FR 60606, September 29, 2011), which established annual catch limit (ACL... mackerel, the Omnibus Amendment and Amendment 11 to the MSB FMP (76 FR 68642; November 7, 2011)...

  9. 77 FR 28311 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery; Closure of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-14

    ... Framework Adjustment 22 to the Scallop FMP (Framework 22) (76 FR 43774, July 21, 2011). Framework 22 set the... guidelines for the use of emergency rules (62 FR 44421; August 21, 1997) specify the following three criteria... of fishing effort in this area, which could have reduced long-term scallop biomass and yield...

  10. 77 FR 73957 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery; Closure of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-12

    ... Adjustment 22 to the Scallop FMP (Framework 22) (76 FR 43774; July 21, 2011), which used 2010 scallop... policy guidelines for the use of emergency rules (62 FR 44421; August 21, 1997) specify the following... could reduce long-term scallop biomass and optimum yield from the ETA, and could compromise the...

  11. 75 FR 28762 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-24

    ... INFORMATION: Background On March 11, 2010 (75 FR 11441), a final rule was published implementing Amendment 10... specifications and management measures for the 2010 fishing year (February 3, 2010, 75 FR 5537), and becomes..., published on March 11, 2010, at 75 FR 11441, is corrected as follows: 1. On page 11450, beginning in...

  12. 76 FR 31491 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery; Closure of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-01

    ... make adjustments to the current scallop access area rotational schedule outlined in the regulations... Register on April 11 and April 29, 2011, respectively (76 FR 19929 and 76 FR 23940), with the comment... undermine the rotational area management program for FY 2012 and beyond, thereby jeopardizing...

  13. 78 FR 70009 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Adjustments to 2014 Sub...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-22

    ... discarded herring. Amendment 4 to the Herring FMP final rule (76 FR 11373, March 2, 2011) revised the... rule for Framework 2 and the 2013-15 specifications on October 4, 2013 (78 FR 61828). Among other... Policy Act analyses to support this action were completed in Amendment 4 (76 FR 11373, March 2, 2011)...

  14. 78 FR 42890 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery and Northeast...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-18

    ..., 2013, the final rule for Joint Framework 24/49 published in the Federal Register (78 FR 27088). The... NGOM as a distinct management area through Amendment 11 to the Scallop FMP (73 FR 20090; April 14,...

  15. Changes in lagoonal marsh morphology at selected northeastern Atlantic coast sites of significance to migratory waterbirds

    USGS Publications Warehouse

    Erwin, R.M.; Sanders, G.M.; Prosser, D.J.

    2004-01-01

    Five lagoonal salt marsh areas, ranging from 220 ha to 3,670 ha, were selected from Cape Cod, Massachusetts to the southern DelMarVa peninsula, Virginia, USA to examine the degree to which Spartina marsh area and microhabitats had changed from the early or mid- 1900s to recent periods. We chose areas based on their importance to migratory bird populations, agency concerns about marsh loss and sea-level rise, and availability of historic imagery. We georeferenced and processed aerial photographs from a variety of sources ranging from 1932 to 1994. Of particular interest were changes in total salt marsh area, tidal creeks, tidal flats, tidal and non-tidal ponds, and open water habitats. Nauset Marsh, within Cape Cod National Seashore, experienced an annual marsh loss of 0.40% (19% from 1947 to 1994) with most loss attributed to sand overwash and conversion to open water. At Forsythe National Wildlife Refuge in southern New Jersey, annual loss was 0.27% (17% from 1932 to 1995), with nearly equal attribution of loss to open water and tidal pond expansion. At Curlew Bay, Virginia, annual loss was 0.20% (9% from 1949 to 1994) and almost entirely due to perimeter erosion to open water. At Gull Marsh, Virginia, a site chosen because of known erosional losses, we recorded the highest annual loss rate, 0.67% per annum, again almost entirely due to erosional, perimeter loss. In contrast, at the southernmost site, Mockhorn Island Wildlife Management Area, Virginia, there was a net gain of 0.09% per annum (4% from 1949 to 1994), with tidal flats becoming increasingly vegetated. Habitat. implications for waterbirds are considerable; salt marsh specialists such as laughing gulls (Larus atricilla), Forster's terns (Sterna forsteri), black rail, (Laterallus jamaicensis), seaside sparrow (Ammodramus maritimus), and saltmarsh sharp-tailed sparrow (Ammodramus caudacutus) are particularly at risk if these trends continue, and all but the laughing gull are species of concern to state and federal managers.

  16. 77 FR 52 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery; Framework Adjustment 23

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-03

    ... measures to: Minimize impacts on sea turtles through the requirement of a turtle deflector dredge; improve.... According to recent research indicating where sea turtle interactions most often occur, the proposed area... loggerheads, but Kemps ridley turtles and one green sea turtle have also been observed to interact...

  17. 77 FR 20728 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery; Framework Adjustment 23

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-06

    ... cumulatively benefit sea turtle conservation, while not compromising the structural integrity of the dredge...)(11)), TDDs are expected to provide an additional conservation benefit to sea turtles by reducing the... Management Council and includes measures to: Minimize impacts on sea turtles through the requirement of...

  18. 76 FR 43773 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery; Framework Adjustment 22

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-21

    ... TAC; management measures to minimize impacts of incidental take of sea turtles as required by the... Minimize the Impacts of Incidental Take of Sea Turtles Under the Endangered Species Act (ESA), each Federal... jeopardize, the continued existence of four sea turtles species (Kemp's ridley, loggerhead, green,...

  19. 78 FR 33020 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Amendment 5

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-03

    .... SUPPLEMENTARY INFORMATION: Background On May 8, 2008 (73 FR 26082), the Council published a notice of intent... on December 28, 2009, (74 FR 68577) announcing the split between the amendments, and that impacts... Secretary of Commerce, was published in the Federal Register on April 22, 2013 (78 FR 23733). The...

  20. 76 FR 66260 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-26

    ... from these requirements because they have a life cycle of less than 1 year. This action also proposes... requirements because they have a life cycle of less than 1 year. For both squid species, regulations at Sec... finalized regulations implementing the Omnibus Amendment (76 FR 60606, September 29, 2011),...

  1. 76 FR 79610 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Adjustment to 2012 Annual...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-22

    ... for 2010-2012, which were approved by NMFS on August 12, 2010 (75 FR 48874). Although herring is not... to the Herring FMP (Amendment 4) (76 FR 11373, March 2, 2011) revised the specification-setting... requirements to obtain more timely catch reports (76 FR 54385, September 1, 2011). As a result of...

  2. 77 FR 67624 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Adjustment to 2013 Annual...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-13

    ... by NMFS on August 12, 2010 (75 FR 48874). The stock-wide herring ACL (91,200 mt) is divided among... Herring FMP (Amendment 4) (76 FR 11373, March 2, 2011) revised the specification-setting process, bringing... 2012 herring specifications in a final rule, which became effective on February 24, 2012 (77 FR...

  3. 77 FR 10978 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Adjustment to 2012 Annual...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-24

    ..., which were approved by NMFS on August 12, 2010 (75 FR 48874). Although herring is not overfished and is... FMP (Amendment 4) (76 FR 11373, March 2, 2011) revised the specification-setting process, bringing the... September 2011, NMFS revised vessels reporting requirements to obtain more timely catch reports (76 FR...

  4. 78 FR 12625 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Adjustment to 2013 Annual...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-25

    ... specifications for 2010-2012, which were approved by NMFS on August 12, 2010 (75 FR 48874). The Herring FMP... Area 3. Amendment 4 to the Herring FMP (Amendment 4) (76 FR 11373, March 2, 2011) revised the... Amendment 4 (76 FR 11373, March 2, 2011). This final rule has been determined to be not significant...

  5. 78 FR 27088 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery and Northeast...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-09

    ... Gilbert, Fishery Policy Analyst, 978-281-9244; fax 978-281-9135. SUPPLEMENTARY INFORMATION: Background The... (78 FR 16574), with a 15-day public comment period that ended April 1, 2013. NMFS received eight... the Scallop FMP (Amendment 11; 72 FR 20090; April 14, 2008) fleet allocations, with 94.5...

  6. Reproductive biology of Urotrygon microphthalmum (Batoidea: Urotrygonidae) from north-eastern Brazil, tropical west Atlantic Ocean.

    PubMed

    Santander-Neto, J; Araújo, M L G; Lessa, R P

    2016-07-01

    The reproductive biology of Urotrygon microphthalmum was studied based on specimens caught as by-catch in shrimp (Litopenaeus schmitti, Xiphopenaeus kroyeri, Farfantepenaeus subtilis and Farfantepenaeus brasiliensis) fishing operations between March 2010 and March 2012 on the coast of Pernambuco, Brazil. Females reached a larger total length (LT ) and total body mass (MT ) (298 mm and 148 g) than males (250 mm and 90 g). Length at maturity was estimated to be 188 and 199 mm LT for males and females. Uterine fecundity ranged from one to four embryos (mean ± s.d.: 1·85 ± 0·45). Size at birth was estimated to be 105 mm LT . Gestation lasted between 4 and 5 months. The reproductive cycle of U. microphthalmum is hypothesized to be asynchronous and biannual.

  7. 75 FR 63791 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Amendment 4

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-18

    ... Standard 1 guidelines task the Council with determining which specific target stocks and/or non-target... or personal use, and non- target stocks are fish caught incidentally during the pursuit of target... is the only stock directly managed by the Herring FMP. Because there may be non-target stocks...

  8. 78 FR 14230 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-05

    ... for Framework Adjustment 7, are available from: Dr. Christopher M. Moore, Executive Director, Mid... NMFS published a proposed rule for Framework Adjustment 7 on December 13, 2012 (77 FR 74159). The... Butterfish (MSB) Fishery Management Plan (FMP) (75 FR 11441, March 11, 2010) as a means of reducing...

  9. 77 FR 71720 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-04

    ... Fishery Management Council, including the Framework Document, are available from: Dr. Christopher M. Moore... on September 21, 2012 (77 FR 58507). Additional background information and detail on why and how... 11 to the MSB FMP (76 FR 68642, November 7, 2011) implemented a three-tiered mackerel limited...

  10. 75 FR 63721 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery; Framework Adjustment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-18

    ..., the final rule for Framework 21 published in the Federal Register (75 FR 36559). The purpose of... through the final rule to Amendment 11 to the Scallop FMP (April 14, 2008; 73 FR 20090). These... (April 27, 2010; 75 FR 22073) and final rules to implement Framework 21. Classification Pursuant to 5...

  11. 76 FR 34947 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Regulatory Amendment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-15

    ... was most recently amended on March 2, 2011 (76 FR 11373), in Amendment 4 to the Herring FMP (Amendment... stock assessment that over-estimates biomass (75 FR 48874, August 12, 2010). While the herring optimum... June 2007 (72 FR 11252, March 31, 2007) to better match the capacity of the fleet to the size of...

  12. 76 FR 54385 - Fisheries of the Northeastern United States; Atlantic Herring Fishery; Regulatory Amendment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-01

    ... revising reporting requirements for the herring fishery was published on June 15, 2011 (75 FR 34947), with... daily via vessel monitoring systems (VMS), open access herring vessels to report catch weekly via the... report herring catch daily via VMS; open access herring vessels report catch weekly via IVR; and...

  13. Profile of South Africa

    SciTech Connect

    Fox, G.J.; Tonneson, L.C.

    1996-08-01

    A broad overview of the Republic of South Africa`s nuclear energy program is presented. Economic aspects are the main focus of the article, and numerical data is provided for electricity generation and use and uranium production. The role of the molecular laser isotope process for enrichment is discussed. The research reactor program, waste disposal and decommissioning, mining history, uranium production, and nonproliferation policy are other highlighted topics.

  14. Astronomy Landscape in Africa

    NASA Astrophysics Data System (ADS)

    Nemaungani, Takalani

    2015-01-01

    The vision for astronomy in Africa is embedded in the African Space Policy of the African Union in early 2014. The vision is about positioning Africa as an emerging hub for astronomy sciences and facilities. Africa recognized the need to take advantage of its natural resource, the geographical advantage of the clear southern skies and pristine sites for astronomy. The Pan African University (PAU) initiative also presents an opportunity as a post-graduate training and research network of university nodes in five regions of Africa and supported by the African Union. The Southern African node based in South Africa concentrates on space sciences which also includes astronomy. The PAU aims to provide the opportunity for advanced graduate training and postgraduate research to high-performing African students. Objectives also include promoting mobility of students and teachers and harmonizing programs and degrees.A number of astronomy initiatives have burgeoned in the Southern African region and these include the Southern Africa Largest Optical Telescope (SALT), HESS (High Energy Stereoscopic System), the SKA (Square Kilometre Array) and the AVN (African Very Long Baseline Interferometer Network). There is a growing appetite for astronomy sciences in Africa. In East Africa, the astronomy community is well organized and is growing - the East African Astronomical society (EAAS) held its successful fourth annual conference since 2010 on 30 June to 04 July 2014 at the University of Rwanda. Centred around the 'Role of Astronomy in Socio-Economic Transformation,' this conference aimed at strengthening capacity building in Astronomy, Astrophysics and Space Science in general, while providing a forum for astronomers from the region to train young and upcoming scientists.

  15. Usutu virus in Africa.

    PubMed

    Nikolay, Birgit; Diallo, Mawlouth; Boye, Cheikh Saad Bouh; Sall, Amadou Alpha

    2011-11-01

    Usutu virus (USUV) was discovered in South Africa in 1959. Since then, it has been reported in several African countries including Senegal, Central African Republic, Nigeria, Uganda, Burkina Faso, Cote d'Ivoire, and Morocco. In 2001, USUV has been identified for the first time outside of Africa, namely in Europe, where it caused a significant mortality among blackbirds in Vienna, Austria. In 2009, the first two human cases of USUV infection in Europe have been reported in Italy, causing encephalitis in immunocompromised patients. The host range in Africa includes mainly Culex mosquitoes, birds, and also humans with one benign and one severe case. Given its role as a potential human pathogen and the similar appearance compared with other emerging arboviruses, it is essential to investigate the natural history and ecology of USUV in Africa. In this regard, we review the emergence of USUV in Africa, summarizing data about isolations, host range, and potential vectors, which should help to improve our understanding of the factors underlying the circulation of USUV in Europe and Africa. PMID:21767160

  16. Mapping tectonic deformation in the crust and upper mantle beneath Europe and the North Atlantic Ocean.

    PubMed

    Zhu, Hejun; Tromp, Jeroen

    2013-08-23

    We constructed a three-dimensional azimuthally anisotropic model of Europe and the North Atlantic Ocean based on adjoint seismic tomography. Several features are well correlated with historical tectonic events in this region, such as extension along the North Atlantic Ridge, trench retreat in the Mediterranean, and counterclockwise rotation of the Anatolian Plate. Beneath northeastern Europe, the direction of the fast anisotropic axis follows trends of ancient rift systems older than 350 million years, suggesting "frozen-in" anisotropy related to the formation of the craton. Local anisotropic strength profiles identify the brittle-ductile transitions in lithospheric strength. In continental regions, these profiles also identify the lower crust, characterized by ductile flow. The observed anisotropic fabric is generally consistent with the current surface strain rate measured by geodetic surveys. PMID:23929947

  17. First observations of megafaunal communities inhabiting George Bligh Bank, Northeast Atlantic

    NASA Astrophysics Data System (ADS)

    Narayanaswamy, Bhavani E.; Hughes, David J.; Howell, Kerry L.; Davies, Jaime; Jacobs, Colin

    2013-08-01

    George Bligh Bank, situated at the north-eastern end of the Rockall Plateau, forms part of an extensive system of elevated submarine topography in the UK's Exclusive Economic Zone of the northeast Atlantic. Through the UK's Strategic Environmental Assessment programme, these seamounts and offshore banks have only recently been investigated in any detail, allowing the first photographic record of epibenthic megafaunal communities. The results presented here are based on photographic and video observations along seven transects on George Bligh Bank, covering a depth range from 425 to 1338 m. Diverse communities of sedentary suspension-feeding organisms were observed along five of the seven transects, with some evidence of localised hard coral frameworks. Community composition on George Bligh Bank is similar to those observed on other hard substrata in the deep northeast Atlantic.

  18. Advancing decadal-scale climate prediction in the North Atlantic sector.

    PubMed

    Keenlyside, N S; Latif, M; Jungclaus, J; Kornblueh, L; Roeckner, E

    2008-05-01

    The climate of the North Atlantic region exhibits fluctuations on decadal timescales that have large societal consequences. Prominent examples include hurricane activity in the Atlantic, and surface-temperature and rainfall variations over North America, Europe and northern Africa. Although these multidecadal variations are potentially predictable if the current state of the ocean is known, the lack of subsurface ocean observations that constrain this state has been a limiting factor for realizing the full skill potential of such predictions. Here we apply a simple approach-that uses only sea surface temperature (SST) observations-to partly overcome this difficulty and perform retrospective decadal predictions with a climate model. Skill is improved significantly relative to predictions made with incomplete knowledge of the ocean state, particularly in the North Atlantic and tropical Pacific oceans. Thus these results point towards the possibility of routine decadal climate predictions. Using this method, and by considering both internal natural climate variations and projected future anthropogenic forcing, we make the following forecast: over the next decade, the current Atlantic meridional overturning circulation will weaken to its long-term mean; moreover, North Atlantic SST and European and North American surface temperatures will cool slightly, whereas tropical Pacific SST will remain almost unchanged. Our results suggest that global surface temperature may not increase over the next decade, as natural climate variations in the North Atlantic and tropical Pacific temporarily offset the projected anthropogenic warming.

  19. Atlantic surfclam connectivity within the Middle Atlantic Bight: Mechanisms underlying variation in larval transport and settlement

    NASA Astrophysics Data System (ADS)

    Zhang, Xinzhong; Munroe, Daphne; Haidvogel, Dale; Powell, Eric N.

    2016-05-01

    Larval transport and settlement have been shown in various studies to be essential in determining population abundance and connectivity for benthic invertebrates. This transport is influenced by both the physical environment and biological behavior. The Atlantic surfclam, Spisula solidissima, is a commercially important benthic invertebrate fishery species along the U.S northeastern coast. In this study, a physical circulation model is coupled to a surfclam larval model to investigate the dynamics of larval transport and settlement within the Middle Atlantic Bight (MAB) shelf in 2006. The main physical mechanisms causing variability in larval transport and settlement are also examined. Model results show that surfclam larvae released from July to early October experience relatively larger settlement rates, due to higher average temperatures experienced by larvae. Larval along-shore transport exhibits a mean down-coast pattern following the coastal current from the northeast to the southwest, with most high-frequency (period of 2-10 days) variations caused by fluctuations in the along-shore surface wind stress, and with seasonal variations speculated to be driven mainly by changes in the across-shelf density gradient. Larval across-shelf movement is highly correlated with the along-shore surface wind stress mediated by coastal upwelling and downwelling episodes, but the correlation is further dependent on the vertical distribution of the larvae, particularly their position relative to the thermocline. Most surfclam larvae released from the Middle Atlantic shelf stay below the thermocline and experience a net onshore transport during the summer-stratified season when upwelling-favorable wind forcing dominates. A proposed critical value of water temperature at the thermocline successfully regulates the observed patterns of vertical distribution of surfclam larvae and their across-shelf movement off the New Jersey and South Virginia shelves; that is, when the water

  20. North Atlantic Bloom

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Reminiscent of the distinctive swirls in a Van Gogh painting, millions of microscopic plants color the waters of the North Atlantic with strokes of blue, turquoise, green, and brown. Fed by nutrients that have built up during the winter and the long, sunlit days of late spring and early summer, the cool waters of the North Atlantic come alive every year with a vivid display of color. The microscopic plants, called phytoplankton, that give the water this color are the base of the marine food chain. Some species of phytoplankton are coated with scales of calcium (chalk), which turn the water electric blue. Chlorophyll and other light-capturing pigments in others give the water a deep green hue. The proliferation of many different species in various stages of growth and decay provides many nuances of color in this concentrated bloom. The bloom stretches across hundreds of kilometers, well beyond the edges of this photo-like image, captured on June 23, 2007, by the Moderate Resolution Imaging Spectroradiometer (MODIS) flying aboard NASA's Aqua satellite. The upper left edge of the image is bounded by Greenland. Iceland is in the upper right. Plumes of dust are blowing off the island, probably adding nutrients to the surface waters to its south. NASA image courtesy Norman Kuring, Ocean Color Group at NASA Goddard Space Flight Center

  1. Extratropical North Atlantic SST influence on Sahel rainfall

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Chiang, J. C.

    2013-12-01

    imposed as lateral boundary conditions. A moisture budget analysis of the GCM anomalies further suggests that reductions of humidity and monsoon flow are dominant processes through which the cooling reduces the Sahel rainfall. The strength of the teleconnection, inferred from air temperature changes due to radiative feedbacks diagnosed with a radiative kernel technique, is shown to be tied to low cloud cover over the Atlantic cooling region and the greenhouse effect of moisture over North Africa. Sahel summer climates: upper panels: anomalies in an AGCM simulation with 2K North Atlantic cooling; lower panels: difference between 1970-1979 and 1950-1959 in observation

  2. The long-range transport of southern African aerosols to the tropical South Atlantic

    NASA Astrophysics Data System (ADS)

    Swap, R.; Garstang, M.; Macko, S. A.; Tyson, P. D.; Maenhaut, W.; Artaxo, P.; KâLlberg, P.; Talbot, R.

    1996-10-01

    Two episodes of long-range aerosol transport (4000 km) from southern Africa into the central tropical South Atlantic are documented. Stable nitrogen isotope analysis, multielemental analysis, and meteorological observations on local and regional scales are used to describe the observed surface aerosol chemistry during these transport episodes. The chemical, kinematic, and thermodynamic analyses suggest that for the central tropical South Atlantic, west Africa between 0° and 10°S is the primary air mass source region (over 50%) during austral spring. Over 70% of all air arriving in the lower and middle troposphere in the central tropical South Atlantic comes from a broad latitudinal band extending from 20°S to 10°N. Air coming from the east subsides and is trapped below the midlevel and trade wind inversion layers. Air from the west originates at higher levels (500 hPa) and contributes less than 30% of the air masses arriving in the central tropical South Atlantic. The source types of aerosols and precursor trace gases extend over a broad range of biomes from desert and savanna to the rain forest. During austral spring, over this broad region, processes include production from vegetation, soils, and biomass burning. The aerosol composition of air masses over and the atmospheric chemistry of the central South Atlantic is a function of the supply of biogenic, biomass burning, and aeolian emissions from tropical Africa. Rainfall is a common controlling factor for all three sources. Rain, in turn, is governed by the large-scale circulations which show pronounced interannual variability. The field measurements were taken in an extremely dry year and reflect the circulation and transport fields typical of these conditions.

  3. Early Jurassic Dikes as Tectonic Features in Northeastern North America

    NASA Astrophysics Data System (ADS)

    McHone, J. G.

    2001-05-01

    Five great dolerite dike systems extend for hundreds of km through northeastern North America. Each dike system contains a distinct tholeiite magma that was generated during the massive igneous paroxysm of 201 Ma (near the Tr-J boundary), and which is part of the enormous central Atlantic magmatic province (CAMP) that preceded the breakup of Pangaea. The individual dike basalts formed via mantle melting and fractionation processes that remain somewhat mysterious, but magmatic pulses of more than 50,000 km3 are evidenced by surface lavas, sills, and large dikes. The dikes crossed several active Mesozoic rift basins and interacted with some extensional basin faults, and they also produced large sills and lava flows within and above Triassic basin strata. Both the basins and the dikes show local trend changes that apparently reflect lithospheric-orogenic fabrics and/or Mesozoic stress systems, as understood from surface observations (maps and measurements). However, the regional trends and distribution of the dikes do not correspond well with the geography and geometry of basin structures. How can rift-dike fractures be independent of contemporaneous rift-basin faults? Unlike the upper-crustal structures that are mapped as basin controls, the dikes represent much deeper lithospheric fractures that were initiated by upper-mantle dynamics. The process of dike propagation should be similar to hydrofracturing, in which the confining stress pattern is more influential than the anisotropy of the surrounding rock. The dikes intruded both vertically and laterally through the lithosphere as their infilling magmas moved rapidly from individual (?) mantle or deep-lithospheric source zones, a process rarely observed but which is modelled through geophysics and experimental petrology. Despite only small age differences, North American dike systems formed in overlapping swarms with variable trends from NW-SE to N-S to NE-SW along 2500 km of eastern North America. These trends must

  4. Hematologically and genetically distinct forms of sickle cell anemia in Africa. The Senegal type and the Benin type.

    PubMed

    Nagel, R L; Fabry, M E; Pagnier, J; Zohoun, I; Wajcman, H; Baudin, V; Labie, D

    1985-04-01

    Patients with sickle cell anemia vary in the hematologic and clinical features of their disease, in part because of variability in the presence of linked and unlinked genes that modify the expression of the disease. The hemoglobin S gene is strongly linked to three different haplotypes of polymorphic endonuclease-restriction sites of the beta-like gene cluster (genes in the vicinity of the beta-globin gene)--one prevalent in Atlantic West Africa, another in central West Africa, and yet another in Bantu-speaking Africa (equatorial, East, and southern Africa). We have studied the differences in the hematologic characteristics of patients with sickle cell anemia from the first two geographical areas. We find that the Senegalese (Atlantic West Africa) patients have higher levels of hemoglobin F, a preponderance of G gamma chains in hemoglobin F, a lower proportion of very dense red cells, and a lower percentage of irreversibly sickled cells than those from Benin (central West Africa). We interpret these data to mean that the gamma-chain composition and the hemoglobin F level are haplotype linked and that the decrease in the percentage of dense cells and irreversibly sickled cells is secondary to the elevation in the hemoglobin F level. Patients with sickle cell anemia in the New World probably correspond to various combinations of these types, in addition to the still hematologically undefined haplotype associated with sickle cell anemia in the Bantu-speaking areas of Africa. PMID:2579336

  5. Convective Lofting Links Indian Ocean Air Pollution to Paradoxical South Atlantic Ozone Maxima

    NASA Technical Reports Server (NTRS)

    Chatfield, Robert B.; Guan, Hong; Thompson, Anne M.; Witte, Jacquelyn C.

    2003-01-01

    We describe a broad resolution of the "Atlantic Paradox" concerning the seasonal and geographic distribution of tropical tropospheric ozone. We describe periods of significant maximum tropospheric O3 for Jan.-April, 1999, exploiting satellite estimates and SHADOZ (Southern Hemisphere Additional Ozonesondes). Trajectory analyses connecting sondes and Total Tropospheric Ozone (TTO)O3 maps suggest a complex influence from the Indian Ocean: beginning with mixed combustion sources, then low level transport, cumulonimbus venting, and finally high-level transport to the west, with possible mixing over Africa. For the Jan.- March highest column-O3 periods in the Atlantic, distinct sounding peaks trace to specific NO sources, especially lightning, while in the same episodes, recurring every 30 or 60 days, more diffuse buildups of Indian-to-Atlantic pollution make important contributions.

  6. Convective lofting links Indian Ocean air pollution to paradoxical South Atlantic ozone maxima

    NASA Technical Reports Server (NTRS)

    Chatfield, R. B.; Guan, H.; Thompson, A. M.; Witte, J. C.

    2005-01-01

    We describe a broad resolution of the Atlantic Parado concerning the seasonal and geographic distribution, of tropical tropospheric ozone. We highlight periods of significant maximum tropospheric O3 for Jan.- April, 1999, exploiting satellite estimates and SHADOZ (Southern Hemisphere Additional Ozonesondes). Trajectory analyses connecting sondes and Total Tropospheric Ozone (TTO) maps suggest a complex influence from the Indian Ocean: beginning with mixed combustion sources, then low level transport, cumulonimbus venting, possible stratospheric input, and finally high-level transport to the west, with possible mixing over Africa. For the Jan.-March highest column-O3 periods in the Atlantic, distinct sounding peaks trace to specific NO sources, especially lightning, while in the same episodes, recurring every 20-50 days, more diffuse buildups of Indian-to-Atlantic pollution make important contributions.

  7. Aerosol interactions with African/Atlantic climate dynamics

    NASA Astrophysics Data System (ADS)

    Hosseinpour, F.; Wilcox, E. M.

    2014-07-01

    Mechanistic relationships exist between variability of dust in the oceanic Saharan air layer (OSAL) and transient changes in the dynamics of Western Africa and the tropical Atlantic Ocean. This study provides evidence of possible interactions between dust in the OSAL region and African easterly jet-African easterly wave (AEJ-AEW) system in the climatology of boreal summer, when easterly wave activity peaks. Synoptic-scale changes in instability and precipitation in the African/Atlantic intertropical convergence zone are correlated with enhanced aerosol optical depth (AOD) in the OSAL region in response to anomalous 3D overturning circulations and upstream/downstream thermal anomalies at above and below the mean-AEJ level. Upstream and downstream anomalies are referred to the daily thermal/dynamical changes over the West African monsoon region and the Eastern Atlantic Ocean, respectively. Our hypothesis is that AOD in the OSAL is positively correlated with the downstream AEWs and negatively correlated with the upstream waves from climatological perspective. The similarity between the 3D pattern of thermal/dynamical anomalies correlated with dust outbreaks and those of AEWs provides a mechanism for dust radiative heating in the atmosphere to reinforce AEW activity. We proposed that the interactions of OSAL dust with regional climate mainly occur through coupling of dust with the AEWs.

  8. Simulation of Rainfall Variability Over West Africa

    NASA Astrophysics Data System (ADS)

    Bader, J.; Latif, M.

    The impact of sea surface temperature (SST) and vegetation on precipitation over West Africa is investigated with the atmospheric general circulation model ECHAM4.x/T42. Ensemble experiments -driven with observed SST- show that At- lantic SST has a significant influence on JJA precipitation over West Africa. Four- teen experiments were performed in which the climatological SST was enhanced or decreased by one Kelvin in certain ocean areas. Changing SST in the eastern tropi- cal Atlantic only caused significant changes along the Guinea Coast, with a positive SSTA increasing rainfall and a negative reducing it. The response was nearly linear. Changing SST in other ocean areas caused significant changes over West Africa, es- pecially in the Sahel area. The response is found to be non linear, with only negative SSTA leading to significant reduction in Sahel rainfall. Also, the impact of the SSTAs from the different ocean regions was not additive with respect to the rainfall. Four simulations with a coupled model (the simple dynamic vegetation model (SVege) and the ECHAM4-AGCM were coupled) were also performed, driven with observed SST from 1945 to 1998. The standard ECHAM-AGCM -forced by the same observed SST- was able to reproduce the drying trend from the fifties to the mid-eighties in the Sahel, but failed to mirror the magnitude of the rainfall anomalies. The coupled model was not only able to reproduce this drying trend, but was also able to better reproduce the amplitudes of the rainfall anomalies. The dynamic vegetation acted like an amplifier, increasing the SST induced rainfall anomalies.

  9. Invariable biomass-specific primary production of taxonomically discrete picoeukaryote groups across the Atlantic Ocean.

    PubMed

    Grob, Carolina; Hartmann, Manuela; Zubkov, Mikhail V; Scanlan, Dave J

    2011-12-01

    Oceanic photosynthetic picoeukaryotes (< 3 µm) are responsible for > 40% of total primary production at low latitudes such as the North-Eastern tropical Atlantic. In the world ocean, warmed by climate changes, the expected gradual shift towards smaller primary producers could render the role of photosynthetic picoeukaryotes even more important than they are today. Little is still known, however, about how the taxonomic composition of this highly diverse group affects primary production at the basin scale. Here, we combined flow cytometric cell sorting, NaH¹⁴CO₃ radiotracer incubations and class-specific fluorescence in situ hybridization (FISH) probes to determine cell- and biomass-specific inorganic carbon fixation rates and taxonomic composition of two major photosynthetic picoeukaryote groups on a ∼7500-km-long latitudinal transect across the Atlantic Ocean (Atlantic Meridional Transect, AMT19). We show that even though larger cells have, on average, cell-specific CO₂ uptake rates ∼5 times higher than the smaller ones, the average biomass-specific uptake is statistically similar for both groups. On the other hand, even at a high taxonomic level, i.e. class, the contributions to both groups by Prymnesiophyceae, Chrysophyceae and Pelagophyceae are significantly different (P < 0.001 in all cases). We therefore conclude that these group's carbon fixation rates are independent of the taxonomic composition of photosynthetic picoeukaryotes across the Atlantic Ocean. Because the above applies across different oceanic regions the diversity changes seem to be a secondary factor determining primary production.

  10. Hantaviruses in Africa.

    PubMed

    Witkowski, Peter T; Klempa, Boris; Ithete, Ndapewa L; Auste, Brita; Mfune, John K E; Hoveka, Julia; Matthee, Sonja; Preiser, Wolfgang; Kruger, Detlev H

    2014-07-17

    This paper summarizes the progress in the search for hantaviruses and hantavirus infections in Africa. After having collected molecular evidence of an indigenous African hantavirus in 2006, an intensive investigation for new hantaviruses has been started in small mammals. Various novel hantaviruses have been molecularly identified not only in rodents but also in shrews and bats. In addition, the first African hantavirus, Sangassou virus, has been isolated and functionally characterized in cell culture. Less is known about the ability of these hantaviruses to infect humans and to cause diseases. To date, no hantavirus genetic material could be amplified from patients' specimens collected in Africa. Serological studies in West Africa, based on a battery of screening and confirmatory assays, led to the detection of hantavirus antibodies in the human population and in patients with putative hantavirus disease. In addition to this overview, we present original data from seroepidemiological and field studies conducted in the Southern part of Africa. A human seroprevalence rate of 1.0% (n=1442) was detected in the South African Cape Region whereas no molecular evidence for the presence of hantavirus was found in 2500 small animals trapped in South Africa and Namibia.

  11. Hantaviruses in Africa.

    PubMed

    Witkowski, Peter T; Klempa, Boris; Ithete, Ndapewa L; Auste, Brita; Mfune, John K E; Hoveka, Julia; Matthee, Sonja; Preiser, Wolfgang; Kruger, Detlev H

    2014-07-17

    This paper summarizes the progress in the search for hantaviruses and hantavirus infections in Africa. After having collected molecular evidence of an indigenous African hantavirus in 2006, an intensive investigation for new hantaviruses has been started in small mammals. Various novel hantaviruses have been molecularly identified not only in rodents but also in shrews and bats. In addition, the first African hantavirus, Sangassou virus, has been isolated and functionally characterized in cell culture. Less is known about the ability of these hantaviruses to infect humans and to cause diseases. To date, no hantavirus genetic material could be amplified from patients' specimens collected in Africa. Serological studies in West Africa, based on a battery of screening and confirmatory assays, led to the detection of hantavirus antibodies in the human population and in patients with putative hantavirus disease. In addition to this overview, we present original data from seroepidemiological and field studies conducted in the Southern part of Africa. A human seroprevalence rate of 1.0% (n=1442) was detected in the South African Cape Region whereas no molecular evidence for the presence of hantavirus was found in 2500 small animals trapped in South Africa and Namibia. PMID:24406800

  12. ITCZ controls on Late Cretaceous black shale sedimentation in the tropical Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Hofmann, P.; Wagner, T.

    2011-12-01

    This study presents high resolution organic and inorganic proxy records for Coniacian to Santonian black shale on the Demerara Rise (ODP Site 1261) in the western tropical Atlantic off South America. We integrate these records with approximately time equivalent geochemical data from the eastern tropical Atlantic off tropical Africa (ODP Site 959) to extract the underlying relationships of Intertropical Convergence Zone (ITCZ) dynamics and black shale formation in the tropical Cretaceous Atlantic at orbital time scales. The geochemical records from the Demerara Rise show repetitive fluctuations in productivity, ocean redox conditions, and clastic sediment supply consistent with a dynamic paleo-upwelling regime off tropical South America. Upwelling intensity most likely was driven by shifts of the mean annual position of the ITCZ, which connects the large-scale precipitation and wind field patterns of the Hadley cells. Upwelling was strongest off South America and burial of oil-prone organic matter most pronounced when the ITCZ was in its southernmost position, which maximized the impact of NE trade winds on the inner, tropical part of the northern Hadley cell. Geochemical records from the Deep Ivorian Basin (equatorial Atlantic) suggest that source rock formation occurred in phase with regions north of the equator. Off tropical Africa, however, black shale formation was primarily driven by regional rainfall and nutrient export. The results of this study provide a conceptual framework that explains the formation, distribution and quality of petroleum source rocks below the tropical component of the Hadley cells on orbital time scales.

  13. Contributions of Tropical Cyclones to the North Atlantic Climatological Rainfall as Observed from Satellites

    NASA Technical Reports Server (NTRS)

    Rodgers, Edward B.; Adler, Robert F.; Pierce, Harold F.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The tropical cyclone rainfall climatology study that was performed for the North Pacific was extended to the North Atlantic. Similar to the North Pacific tropical cyclone study, mean monthly rainfall within 444 km of the center of the North Atlantic tropical cyclones (i.e., that reached storm stage and greater) was estimated from passive microwave satellite observations during, an eleven year period. These satellite-observed rainfall estimates were used to assess the impact of tropical cyclone rainfall in altering the geographical, seasonal, and inter-annual distribution of the North Atlantic total rainfall during, June-November when tropical cyclones were most abundant. The main results from this study indicate: 1) that tropical cyclones contribute, respectively, 4%, 3%, and 4% to the western, eastern, and entire North Atlantic; 2) similar to that observed in the North Pacific, the maximum in North Atlantic tropical cyclone rainfall is approximately 5 - 10 deg poleward (depending on longitude) of the maximum non-tropical cyclone rainfall; 3) tropical cyclones contribute regionally a maximum of 30% of the total rainfall 'northeast of Puerto Rico, within a region near 15 deg N 55 deg W, and off the west coast of Africa; 4) there is no lag between the months with maximum tropical cyclone rainfall and non-tropical cyclone rainfall in the western North Atlantic, while in the eastern North Atlantic, maximum tropical cyclone rainfall precedes maximum non-tropical cyclone rainfall; 5) like the North Pacific, North Atlantic tropical cyclones Of hurricane intensity generate the greatest amount of rainfall in the higher latitudes; and 6) warm ENSO events inhibit tropical cyclone rainfall.

  14. Multiple cenozoic invasions of Africa by penguins (Aves, Sphenisciformes).

    PubMed

    Ksepka, Daniel T; Thomas, Daniel B

    2012-03-01

    Africa hosts a single breeding species of penguin today, yet the fossil record indicates that a diverse array of now-extinct taxa once inhabited southern African coastlines. Here, we show that the African penguin fauna had a complex history involving multiple dispersals and extinctions. Phylogenetic analyses and biogeographic reconstructions incorporating new fossil material indicate that, contrary to previous hypotheses, the four Early Pliocene African penguin species do not represent an endemic radiation or direct ancestors of the living Spheniscus demersus (blackfooted penguin). A minimum of three dispersals to Africa, probably assisted by the eastward-flowing Antarctic Circumpolar and South Atlantic currents, occurred during the Late Cenozoic. As regional sea-level fall eliminated islands and reduced offshore breeding areas during the Pliocene, all but one penguin lineage ended in extinction, resulting in today's depleted fauna. PMID:21900330

  15. Multiple cenozoic invasions of Africa by penguins (Aves, Sphenisciformes).

    PubMed

    Ksepka, Daniel T; Thomas, Daniel B

    2012-03-01

    Africa hosts a single breeding species of penguin today, yet the fossil record indicates that a diverse array of now-extinct taxa once inhabited southern African coastlines. Here, we show that the African penguin fauna had a complex history involving multiple dispersals and extinctions. Phylogenetic analyses and biogeographic reconstructions incorporating new fossil material indicate that, contrary to previous hypotheses, the four Early Pliocene African penguin species do not represent an endemic radiation or direct ancestors of the living Spheniscus demersus (blackfooted penguin). A minimum of three dispersals to Africa, probably assisted by the eastward-flowing Antarctic Circumpolar and South Atlantic currents, occurred during the Late Cenozoic. As regional sea-level fall eliminated islands and reduced offshore breeding areas during the Pliocene, all but one penguin lineage ended in extinction, resulting in today's depleted fauna.

  16. Variability in Vertical Profiles of Water Vapor Associated with African Aerosol over the Tropical Atlantic

    NASA Astrophysics Data System (ADS)

    Huang, J.; Zhang, C.; Prospero, J. M.

    2007-12-01

    We used four years (2003-2006) of MODIS aerosol optical depth and concurrent AIRS profiled water vapor to explore how the vertical distribution of water vapor may systematically change with outbreaks of African aerosol over the tropical Atlantic Ocean. The first step was to look for a relationship in the Barbados region using in-situ Barbados dust record and the profiled relative humidity from meteorological soundings. We extended the study to the synoptic scale in the West Indies using the MODIS and AIRS products. In the tropical Atlantic, preliminary results indicate that water vapor at 850-1000 hPa is significantly less in July on dusty days than clean days over the northeastern tropical Atlantic [5-25N, 30-20W] where African dust is predominant. In contrast, over the southeastern tropical Atlantic [15S-0, 5W-10E], where African biomass burning smoke prevails, water vapor at 600-1000 hPa is significantly higher in August on smoky days than clean days. Additionally, in January when African mixed aerosol (dust and smoke) is anomalously high over the equatorial eastern tropical Atlantic [5S-5N, 15W-5E], less water vapor is observed at two levels: 925-1000 hPa and 500-600 hPa. It is hypothesized that these results are associated with the non-hygroscopic nature of African dust, the hygroscopic properties of African smoke, and their transport pathways over the tropical Atlantic. These results are useful in the design and diagnostics of model simulations of climate effects of aerosols such as aerosol related precipitation change.

  17. Regional stratigraphy and petroleum geology, North Africa-Middle East

    SciTech Connect

    Peterson, J.A. )

    1991-03-01

    The North Africa-Middle East petroleum provinces are part of the broad sedimentary platform that occupied the northern and northeastern borders of the African-Arabian craton adjacent to the ancestral Hercynian (late Paleozoic) and subsequent Tethyan-Alpine oceans. Carbonate-clastic-evaporite sediments of infra-Cambrian through Holocene age were cyclically deposited in a relatively continuous belt around the eastern and northern borders of the craton, mainly on a broad, shallow-water platform adjacent to the proto-Tethys and Tethys seaway. The Paleozoic section reaches a substantial thickness in the subsurface of the Middle East and in northern Africa adjacent to the Mediterranean Sea, but all or part of it is absent because of nondeposition or erosion over much of the region. Post-Paleozoic deposition was more or less continuous across the entire craton border region in the Middle East and along the northern border of the Sahara platform in North Africa and in Somalia and eastern Ethiopia. Similar marine and associated sedimentary rock facies are present in all of these regions, although paleotectonic-stratigraphic interrelationships and continental paleolatitude positions have greatly affected petroleum generation and accumulation in the specific provinces along the craton border. A series of regional stratigraphic-sedimentary environment, and continental position, layer maps illustrates the relative influence of these factors through geologic time with respect to the relationship between petroleum reservoirs, source rocks, and confining rock facies.

  18. Urbanization and water supplies for northeastern Colorado

    SciTech Connect

    Smith, R.R.

    1981-03-01

    Increasing populations in northeastern Colorado have resulted in reductions in irrigated acreage and the proportionate quantities of water available to support that segment of the agricultural industry. The growth has caused increased demands for municipal-domestic and industrial water supplies from the South Platte and Colorado River Basins. These impacts have been determined by comparing hydrologic data in conjunction with water use for agricultural, municipal-domestic, and industrial purposes between the period 1975 to 1979. Pricing and water rights ownership were also compared for the same period, as were land conversion data, population data, and crop production valuation. Proper administration of nonconsumptive return flows coupled with the importation of water from the Colorado River Basin will provide adequate, industrial, and irrigation water supplies for this growth intense area and downstream farm lands. 8 figures.

  19. Flooding in the Northeastern United States, 2011

    USGS Publications Warehouse

    Suro, Thomas P.; Roland, Mark A.; Kiah, Richard G.

    2015-12-31

    The annual exceedance probability (AEP) for 327 streamgages in the Northeastern United States were computed using annual peak streamflow data through 2011 and are included in this report. The 2011 peak streamflow for 129 of those streamgages was estimated to have an AEP of less than or equal to 1 percent. Almost 100 of these peak streamflows were a result of the flooding associated with Hurricane Irene in late August 2011. More extreme than the 1-percent AEP, is the 0.2-percent AEP. The USGS recorded peak streamflows at 31 streamgages that equaled or exceeded the estimated 0.2-percent AEP during 2011. Collectively, the USGS recorded peak streamflows having estimated AEPs of less than 1 percent in Connecticut, Delaware, Maine, Maryland, Massachusetts, Ohio, Pennsylvania, New Hampshire, New Jersey, New York, and Vermont and new period-of-record peak streamflows were recorded at more than 180 streamgages resulting from the floods of 2011.

  20. Transport of Biomass Burning Emissions from Southern Africa

    NASA Technical Reports Server (NTRS)

    Sinha, Parikhit; Jaegle,Lyatt; Hobbs, Peter V.; Liang, Qing

    2004-01-01

    The transport of biomass burning emissions from southern Africa to the neighboring Atlantic and Indian Oceans during the dry season (May-October) of 2000 is characterized using ground, ozonesonde, and aircraft measurements of carbon monoxide (CO) and ozone (O3) in and around southern Africa, together with the GEOS-CHEM global model of tropospheric chemistry. The model shows a positive bias of approximately 20% for CO and a negative bias of approximately 10-25% for O3 at oceanic sites downwind of fire emissions. Near areas of active fire emissions the model shows a negative bias of approximately 60% and approximately 30% for CO and O3, respectively, likely due to the coarse spatial (2 deg. x 2.5 deg.) and temporal (monthly) resolution of the model compared to that of active fires. On average, from 1994 to 2000, approximately 60 Tg of carbon monoxide (CO) from biomass burning in southern Africa was transported eastward to the Indian Ocean across the latitude band 0 deg. -60 S during the 6 months of the dry season. Over the same time period, approximately 40 Tg of CO from southern African biomass burning was transported westward to the Atlantic Ocean over the latitudes 0 deg. -20 S during the 6-month dry season, but most of that amount was transported back eastward over higher latitudes to the south (21 deg. -60 S). Eastward transport of biomass burning emissions from southern Africa enhances CO concentrations by approximately 4- 13 ppbv per month over the southern subtropical Indian Ocean during the dry season, with peak enhancements in September. Carbon monoxide from southern African and South American biomass burning is seen in the model simulations as far away as Australia, contributing approximately 8 ppbv and approximately 12-15 ppbv CO, respectively, and thus explaining the approximately 20- 25 ppbv observed enhancement of CO over Melbourne in mid-September 2000.

  1. Dual Hurricanes in the Atlantic

    NASA Video Gallery

    Cameras on the International Space Station show views of Hurricane Julia and Hurricane Igor, both moving west-northwest across the Atlantic on Sept. 14, 2010. At the time the video was captured, Ju...

  2. The Atlantic Climate Change Program

    SciTech Connect

    Molinari, R.L. ); Battisti, D. ); Bryan, K. ); Walsh, J. )

    1994-07-01

    The Atlantic Climate Change Program (ACCP) is a component of NOAA's Climate and Global Change Program. ACCP is directed at determining the role of the thermohaline circulation of the Atlantic Ocean on global atmospheric climate. Efforts and progress in four ACCP elements are described. Advances include (1) descriptions of decadal and longer-term variability in the coupled ocean-atmosphere-ice system of the North Atlantic; (2) development of tools needed to perform long-term model runs of coupled simulations of North Atlantic air-sea interaction; (3) definition of mean and time-dependent characteristics of the thermohaline circulation; and (4) development of monitoring strategies for various elements of the thermohaline circulation. 20 refs., 4 figs., 1 tab.

  3. Seafloor methane: Atlantic bubble bath

    NASA Astrophysics Data System (ADS)

    Kessler, John

    2014-09-01

    The release of large quantities of methane from ocean sediments might affect global climate change. The discovery of expansive methane seeps along the US Atlantic margin provides an ideal test bed for such a marine methane-climate connection.

  4. North Atlantic Coastal Tidal Wetlands

    EPA Science Inventory

    The book chapter provides college instructors, researchers, graduate and advanced undergraduate students, and environmental consultants interested in wetlands with foundation information on the ecology and conservation concerns of North Atlantic coastal wetlands. The book c...

  5. North Atlantic Deep Water Formation

    NASA Technical Reports Server (NTRS)

    Bennett, T. (Editor); Broecker, W. S. (Editor); Hansen, J. (Editor)

    1984-01-01

    Various studies concerning differing aspects of the North Atlantic are presented. The three major topics under which the works are classified include: (1) oceanography; (2) paleoclimate; and (3) ocean, ice and climate modeling.

  6. 77 FR 25144 - Fisheries of the South Atlantic; South Atlantic Fishery Management Council; Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-27

    .... Council address: South Atlantic Fishery Management Council, 4055 Faber Place Drive, Suite 201, N... Atlantic Fishery Management Council, 4055 Faber Place Drive, Suite 201, N. Charleston, SC, 29405;...

  7. Out of Africa: the slow train to australasia.

    PubMed

    Waters, Jonathan M; Roy, Michael S

    2004-02-01

    We used mitochondrial DNA (mtDNA) sequences to test biogeographic hypotheses for Patiriella exigua (Asterinidae), one of the world's most widespread coastal sea stars. This small intertidal species has an entirely benthic life history and yet occurs in southern temperate waters of the Atlantic, Indian, and Pacific oceans. Despite its abundance around southern Africa, southeastern Australia, and several oceanic islands, P. exigua is absent from the shores of Western Australia, New Zealand, and South America. Phylogenetic analysis of mtDNA sequences (cytochrome oxidase I, control region) indicates that South Africa houses an assemblage of P. exigua that is not monophyletic (P = 0.04), whereas Australian and Lord Howe Island specimens form an interior monophyletic group. The placement of the root in Africa and small genetic divergences between eastern African and Australian haplotypes strongly suggest Pleistocene dispersal eastward across the Indian Ocean. Dispersal was probably achieved by rafting on wood or macroalgae, which was facilitated by the West Wind Drift. Genetic data also support Pleistocene colonization of oceanic islands (Lord Howe Island, Amsterdam Island, St. Helena). Although many biogeographers have speculated about the role of long-distance rafting, this study is one of the first to provide convincing evidence. The marked phylogeographic structure evident across small geographic scales in Australia and South Africa indicates that gene flow among populations may be generally insufficient to prevent the local evolution of monophyly. We suggest that P. exigua may rely on passive mechanisms of dispersal. PMID:14965897

  8. A Phororhacoid bird from the Eocene of Africa

    NASA Astrophysics Data System (ADS)

    Mourer-Chauviré, Cécile; Tabuce, Rodolphe; Mahboubi, M'hammed; Adaci, Mohammed; Bensalah, Mustapha

    2011-10-01

    The bird fossil record is globally scarce in Africa. The early Tertiary evolution of terrestrial birds is virtually unknown in that continent. Here, we report on a femur of a large terrestrial new genus discovered from the early or early middle Eocene (between ˜52 and 46 Ma) of south-western Algeria. This femur shows all the morphological features of the Phororhacoidea, the so-called Terror Birds. Most of the phororhacoids were indeed large, or even gigantic, flightless predators or scavengers with no close modern analogs. It is likely that this extinct group originated in South America, where they are known from the late Paleocene to the late Pleistocene (˜59 to 0.01 Ma). The presence of a phororhacoid bird in Africa cannot be explained by a vicariant mechanism because these birds first appeared in South America well after the onset of the mid-Cretaceous Gondwana break up (˜100 million years old). Here, we propose two hypotheses to account for this occurrence, either an early dispersal of small members of this group, which were still able of a limited flight, or a transoceanic migration of flightless birds from South America to Africa during the Paleocene or earliest Eocene. Paleogeographic reconstructions of the South Atlantic Ocean suggest the existence of several islands of considerable size between South America and Africa during the early Tertiary, which could have helped a transatlantic dispersal of phororhacoids.

  9. Pan-Atlantic analysis of the overlap of a highly migratory species, the leatherback turtle, with pelagic longline fisheries

    PubMed Central

    Fossette, S.; Witt, M. J.; Miller, P.; Nalovic, M. A.; Albareda, D.; Almeida, A. P.; Broderick, A. C.; Chacón-Chaverri, D.; Coyne, M. S.; Domingo, A.; Eckert, S.; Evans, D.; Fallabrino, A.; Ferraroli, S.; Formia, A.; Giffoni, B.; Hays, G. C.; Hughes, G.; Kelle, L.; Leslie, A.; López-Mendilaharsu, M.; Luschi, P.; Prosdocimi, L.; Rodriguez-Heredia, S.; Turny, A.; Verhage, S.; Godley, B. J.

    2014-01-01

    Large oceanic migrants play important roles in ecosystems, yet many species are of conservation concern as a result of anthropogenic threats, of which incidental capture by fisheries is frequently identified. The last large populations of the leatherback turtle, Dermochelys coriacea, occur in the Atlantic Ocean, but interactions with industrial fisheries could jeopardize recent positive population trends, making bycatch mitigation a priority. Here, we perform the first pan-Atlantic analysis of spatio-temporal distribution of the leatherback turtle and ascertain overlap with longline fishing effort. Data suggest that the Atlantic probably consists of two regional management units: northern and southern (the latter including turtles breeding in South Africa). Although turtles and fisheries show highly diverse distributions, we highlight nine areas of high susceptibility to potential bycatch (four in the northern Atlantic and five in the southern/equatorial Atlantic) that are worthy of further targeted investigation and mitigation. These are reinforced by reports of leatherback bycatch at eight of these sites. International collaborative efforts are needed, especially from nations hosting regions where susceptibility to bycatch is likely to be high within their exclusive economic zone (northern Atlantic: Cape Verde, Gambia, Guinea Bissau, Mauritania, Senegal, Spain, USA and Western Sahara; southern Atlantic: Angola, Brazil, Namibia and UK) and from nations fishing in these high-susceptibility areas, including those located in international waters. PMID:24523271

  10. Pan-atlantic analysis of the overlap of a highly migratory species, the leatherback turtle, with pelagic longline fisheries.

    PubMed

    Fossette, S; Witt, M J; Miller, P; Nalovic, M A; Albareda, D; Almeida, A P; Broderick, A C; Chacón-Chaverri, D; Coyne, M S; Domingo, A; Eckert, S; Evans, D; Fallabrino, A; Ferraroli, S; Formia, A; Giffoni, B; Hays, G C; Hughes, G; Kelle, L; Leslie, A; López-Mendilaharsu, M; Luschi, P; Prosdocimi, L; Rodriguez-Heredia, S; Turny, A; Verhage, S; Godley, B J

    2014-04-01

    Large oceanic migrants play important roles in ecosystems, yet many species are of conservation concern as a result of anthropogenic threats, of which incidental capture by fisheries is frequently identified. The last large populations of the leatherback turtle, Dermochelys coriacea, occur in the Atlantic Ocean, but interactions with industrial fisheries could jeopardize recent positive population trends, making bycatch mitigation a priority. Here, we perform the first pan-Atlantic analysis of spatio-temporal distribution of the leatherback turtle and ascertain overlap with longline fishing effort. Data suggest that the Atlantic probably consists of two regional management units: northern and southern (the latter including turtles breeding in South Africa). Although turtles and fisheries show highly diverse distributions, we highlight nine areas of high susceptibility to potential bycatch (four in the northern Atlantic and five in the southern/equatorial Atlantic) that are worthy of further targeted investigation and mitigation. These are reinforced by reports of leatherback bycatch at eight of these sites. International collaborative efforts are needed, especially from nations hosting regions where susceptibility to bycatch is likely to be high within their exclusive economic zone (northern Atlantic: Cape Verde, Gambia, Guinea Bissau, Mauritania, Senegal, Spain, USA and Western Sahara; southern Atlantic: Angola, Brazil, Namibia and UK) and from nations fishing in these high-susceptibility areas, including those located in international waters.

  11. Pan-atlantic analysis of the overlap of a highly migratory species, the leatherback turtle, with pelagic longline fisheries.

    PubMed

    Fossette, S; Witt, M J; Miller, P; Nalovic, M A; Albareda, D; Almeida, A P; Broderick, A C; Chacón-Chaverri, D; Coyne, M S; Domingo, A; Eckert, S; Evans, D; Fallabrino, A; Ferraroli, S; Formia, A; Giffoni, B; Hays, G C; Hughes, G; Kelle, L; Leslie, A; López-Mendilaharsu, M; Luschi, P; Prosdocimi, L; Rodriguez-Heredia, S; Turny, A; Verhage, S; Godley, B J

    2014-04-01

    Large oceanic migrants play important roles in ecosystems, yet many species are of conservation concern as a result of anthropogenic threats, of which incidental capture by fisheries is frequently identified. The last large populations of the leatherback turtle, Dermochelys coriacea, occur in the Atlantic Ocean, but interactions with industrial fisheries could jeopardize recent positive population trends, making bycatch mitigation a priority. Here, we perform the first pan-Atlantic analysis of spatio-temporal distribution of the leatherback turtle and ascertain overlap with longline fishing effort. Data suggest that the Atlantic probably consists of two regional management units: northern and southern (the latter including turtles breeding in South Africa). Although turtles and fisheries show highly diverse distributions, we highlight nine areas of high susceptibility to potential bycatch (four in the northern Atlantic and five in the southern/equatorial Atlantic) that are worthy of further targeted investigation and mitigation. These are reinforced by reports of leatherback bycatch at eight of these sites. International collaborative efforts are needed, especially from nations hosting regions where susceptibility to bycatch is likely to be high within their exclusive economic zone (northern Atlantic: Cape Verde, Gambia, Guinea Bissau, Mauritania, Senegal, Spain, USA and Western Sahara; southern Atlantic: Angola, Brazil, Namibia and UK) and from nations fishing in these high-susceptibility areas, including those located in international waters. PMID:24523271

  12. Tobacco in Africa.

    PubMed

    Yach, D

    1996-01-01

    Tobacco has been a common commodity in Africa for over three centuries. By 1993, some 500 000 tons of tobacco were being grown in 33 African countries, with only two countries exporting more than they import. Attempts to measure the current and potential impact of the tobacco business on health, society and the environment are still in their early stages, but the need for preventive action is already inescapably clear. Comprehensive control strategies are urgently required to prevent a major epidemic of tobacco-related disease in Africa. PMID:8820139

  13. Causes of mortality across different immigrant groups in Northeastern Italy

    PubMed Central

    Ferroni, Eliana; Pigato, Mara; Avossa, Francesco; Saugo, Mario

    2015-01-01

    Background. Despite massive immigration towards Southern Europe in the last two decades, data on mortality by cause among immigrants in Italy are scarce. The aim of this study was to investigate mortality from all and from specific causes of death among immigrants residing in the Veneto Region (Northeastern Italy). Methods. Mortality records for the period 2008–2013 were extracted from the regional archive of causes of death, whereas population data were obtained from the 2011 Italian census. Immigrants were grouped by area of provenience based on the information on country of citizenship available both in mortality and census data. Standardized Mortality Ratios (SMR) with 95% Confidence Intervals (CI) were computed for the period 2008–2013 in subjects aged 20–59 years, with rates of Italian citizens as a reference. Results. Overall mortality was reduced both in male (SMR 0.86, CI [0.80–0.92]) and female immigrants (SMR 0.72, CI [0.65–0.78]), although an increased risk was observed for subjects from Sub-Saharan Africa. Significantly raised SMR for circulatory diseases were found among Sub-Saharan Africans and Southern Asians in both genders. Sub-Saharan Africans experienced a higher risk of death, especially from cerebrovascular diseases: SMR 4.78 (CI [2.67–7.89]) and SMR 6.09 (CI [1.96–14.2]) in males and females, respectively. Among Southern Asians, the increase in mortality from ischemic heart diseases reached statistical significance in males (SMR 2.53, CI [1.42–4.18]). In spite of a lower risk of death for all neoplasms combined, mortality from cancer of cervix uteri was increased among immigrants (SMR 2.61, CI [1.35–4.56]), as well as for other cancer sites in selected immigrant groups. A raised mortality was found for infectious diseases in Sub-Saharan Africans (both genders), and for transport accidents among females from Eastern Europe. Conclusion. Our study showed great variations in mortality by cause and area of provenience among

  14. Seismotectonics of northeastern United States and adjacent Canada

    NASA Astrophysics Data System (ADS)

    Yang, Jih-Ping; Aggarwal, Yash Pal

    1981-06-01

    Data for local earthquakes recorded by a network of stations in northeastern United States and adjacent Canada were analyzed to study the seismicity, the relationship between earthquakes and known faults, the state of stress, and crustal and upper mantle velocity structure. In addition, portable seismographs were deployed in the field to study aftershocks. As a result, accurate locations for about 364 local earthquakes (2 ≤ mb ≤ 5) and 22 focal mechanism solutions were determined. A comparison of the spatial distribution of these events (1970-1979) with historical earthquakes (1534-1959) reveals that seismic activity in the northeast is relatively stationary in space: those areas that have had little or no seismicity historically are relatively aseismic today, whereas the historically active areas are also active today. The instrumental locations, historical seismicity, and focal mechanism solutions show an internal consistency that help us distinguish two distinct seismogenic provinces. (1) The Adirondack-western Quebec province is a northwesterly trending zone of seismic activity, about 200 km wide and at least 500 km long, extending from the SE Adirondacks into western Quebec, Canada. Thrust faulting on planes striking NNW to NW appears to predominate, and the inferred axis of maximum horizontal compression is largely uniform and trends WSW, nearly parallel to the calculated absolute plate motion of North America. Little or no seismicity is found where anorthosite outcrops at the surface. Correlations between gravity anomalies and earthquake locations suggest that seismic activity in this zone is localized to regions of steep NE or SW gradient in Bouguer anomalies. This zone does not appear to extend southeastward to Boston, as proposed by some workers. (2) The Appalachian province is a northeasterly trending zone of seismic activity extending from northern Virginia to New Brunswick, Canada. Highangle reverse or thrust faulting on N to NE trending planes

  15. On the North Atlantic circulation

    SciTech Connect

    Schmitz, W.J. Jr.; McCartney, M.S. )

    1993-02-01

    A summary for North Atlantic circulation is proposed to replace the circulation scheme hypothesized by Worthington in 1976. Divergences from the previous model are in thermohaline circulation, cross-equatorical transport and Florida Current sources, flow in the eastern Atlantic, circulation in the Newfoundland Basin, slope water currents, and flow pattern near the Bahamas. The circulation patterns presented here are consistent with the majority of of published accounts of flow components. 77 refs., 14 figs., 3 tabs.

  16. Oceanic origin of southeast tropical Atlantic biases

    NASA Astrophysics Data System (ADS)

    Xu, Zhao; Li, Mingkui; Patricola, Christina M.; Chang, Ping

    2014-12-01

    Most coupled general circulation models suffer from a prominent warm sea surface temperature bias in the southeast tropical Atlantic Ocean off the coast of Africa. The origin of the bias is not understood and remains highly controversial. Previous studies suggest that the origin of the bias stems from systematic errors of atmospheric models in simulating surface heat flux and coastal wind, or poorly simulated coastal upwelling. In this study, we show, using different reanalysis and observational data sets combined with a set of eddy-resolving regional ocean model simulations, that systematic errors in ocean models also make a significant contribution to the bias problem. In particular (1) the strong warm bias at the Angola-Benguela front that is maintained by the local wind and the convergence of Angola and Benguela Currents is caused by an overshooting of the Angola Current in ocean models and (2) the alongshore warm bias to the south of the front is caused by ocean model deficiencies in simulating the sharp thermocline along the Angola coast, which is linked to biases in the equatorial thermocline, and the complex circulation system within the Benguela upwelling zone.

  17. South Atlantic Spreading Velocities and Time Scales

    NASA Astrophysics Data System (ADS)

    Clark, S. R.; Smethurst, M. A.; Bianchi, M. C.

    2013-12-01

    Plate reconstructions based on hierarchical spherical rotations have been around for many years. For the breakup of Pangea and Gondwana, these reconstructions are based on two major sources: magnetic isochrons and geological evidence for the onset of rifting and the tightness of the fit between continents. These reconstructions imply spreading velocities and it is the changes in velocities that can be used to probe questions of the forces moving plates around. In order to calculate the velocities correctly though, the importance of the choice of geologic time scale is often ignored. In this talk, we focus on the South Atlantic and calculate the spreading velocity errors implied by the choice of time scale for three major epochs: the Cenozoic and Late Mesozoic, the Cretaceous Quiet Zone and the Late Cretaceous to the Early Jurassic. In addition, we report the spreading velocities implied through these phases by various available magnetic isochron-derived reconstructions and the geological fits for South America and Africa used by large scale global reconstruction as well as in recent papers. Finally, we will highlight the implications for the choice of the mantle reference frame on African plate velocities.

  18. Evidence for episodic acidification effects on migrating Atlantic salmon Salmo salar smolts.

    PubMed

    Kelly, J T; Lerner, D T; O'Dea, M F; Regish, A M; Monette, M Y; Hawkes, J P; Nislow, K H; McCormick, S D

    2015-11-01

    Field studies were conducted to determine levels of gill aluminium as an index of acidification effects on migrating Atlantic salmon Salmo salar smolts in the north-eastern U.S.A. along mainstem river migration corridors in several major river basins. Smolts emigrating from the Connecticut River, where most (but not all) tributaries were well buffered, had low or undetectable levels of gill aluminium and high gill Na(+) /K(+) -ATPase (NKA) activity. In contrast, smolts emigrating from the upper Merrimack River basin where most tributaries are characterized by low pH and high inorganic aluminium had consistently elevated gill aluminium and lower gill NKA activity, which may explain the low adult return rates of S. salar stocked into the upper Merrimack catchment. In the Sheepscot, Narraguagus and Penobscot Rivers in Maine, river and year-specific effects on gill aluminium were detected that appeared to be driven by underlying geology and high spring discharge. The results indicate that episodic acidification is affecting S. salar smolts in poorly buffered streams in New England and may help explain variation in S. salar survival and abundance among rivers and among years, with implications for the conservation and recovery of S. salar in the north-eastern U.S.A. These results suggest that the physiological condition of outmigrating smolts may serve as a large-scale sentinel of landscape-level recovery of atmospheric pollution in this and other parts of the North Atlantic region. PMID:26399385

  19. Evidence for episodic acidification effects on migrating Atlantic salmon Salmo salar smolts.

    PubMed

    Kelly, J T; Lerner, D T; O'Dea, M F; Regish, A M; Monette, M Y; Hawkes, J P; Nislow, K H; McCormick, S D

    2015-11-01

    Field studies were conducted to determine levels of gill aluminium as an index of acidification effects on migrating Atlantic salmon Salmo salar smolts in the north-eastern U.S.A. along mainstem river migration corridors in several major river basins. Smolts emigrating from the Connecticut River, where most (but not all) tributaries were well buffered, had low or undetectable levels of gill aluminium and high gill Na(+) /K(+) -ATPase (NKA) activity. In contrast, smolts emigrating from the upper Merrimack River basin where most tributaries are characterized by low pH and high inorganic aluminium had consistently elevated gill aluminium and lower gill NKA activity, which may explain the low adult return rates of S. salar stocked into the upper Merrimack catchment. In the Sheepscot, Narraguagus and Penobscot Rivers in Maine, river and year-specific effects on gill aluminium were detected that appeared to be driven by underlying geology and high spring discharge. The results indicate that episodic acidification is affecting S. salar smolts in poorly buffered streams in New England and may help explain variation in S. salar survival and abundance among rivers and among years, with implications for the conservation and recovery of S. salar in the north-eastern U.S.A. These results suggest that the physiological condition of outmigrating smolts may serve as a large-scale sentinel of landscape-level recovery of atmospheric pollution in this and other parts of the North Atlantic region.

  20. Telecommunications and Development in Africa.

    ERIC Educational Resources Information Center

    Kiplagat, B. A., Ed.; Werner, M. C. M., Ed.

    The Telecommunications Foundation of Africa (TFA) was created in 1992 out of a conviction that insufficient telecommunications in Africa are an impediment to economic growth, and that more resources could be mobilized to strengthen this sector. This volume was made by TFA for readers both inside and outside of Africa and the telecommunications…

  1. Family Planning Programmes in Africa.

    ERIC Educational Resources Information Center

    Pradervand, Pierre

    The countries discussed in this paper are the francophone countries of West Africa and the Republic of Congo, with comparative references made to North Africa (mainly Morocco, Algeria, and Tunisia). Obstacles to the adoption of family planning in the countries of tropical Africa are a very high mortality rate among children; a socioeconomic…

  2. Country Energy Profile, South Africa

    SciTech Connect

    1995-08-01

    This country energy profile provides energy and economic information about South Africa. Areas covered include: Economics, demographics, and environment; Energy situation; Energy structure; Energy investment opportunities; Department of Energy (DOE) programs in South Africa; and a listing of International aid to South Africa.

  3. Geographical distribution of pelagic decapod shrimp in the Atlantic Ocean.

    PubMed

    Judkins, David C

    2014-12-16

    Ninety-one species of pelagic decapod shrimp were identified in 938 midwater-trawl collections taken between 1963 and 1974 from the North and South Atlantic. Distributional maps are provided for the most frequently occurring species. Nighttime abundance of most species was greatest within the upper 200 m. Degree of geographical overlap was estimated using the geometric mean of the proportion of joint occurrences with a value ≥ 0.5 deemed significant. Geographical distributions tended to be unique, and only 31 species had values ≥ 0.5 with one or more other species. Species within genera and within phylogenetic subgroups of Sergia were generally parapatric or partially overlapping in distribution. Five geographical groupings of co-occurring species across genera were identified: Subpolar-Temperate, Southern Hemisphere, Central, Tropical, Eastern Tropical and Western Tropical. The two species of the Southern Hemisphere group are circumpolar at temperate latitudes. The 12 species of the Central group occurred throughout the subtropical and tropical North and South Atlantic. The eight species of the Tropical group occurred broadly across the equatorial Atlantic and Caribbean with ranges usually extending into the Gulf of Mexico and northward in the Gulf Stream. The two species of the Western Tropical group occurred most often in the western tropics, but there were scattered occurrences at subtropical latitudes. The four species of the Eastern Tropical group were endemic to the Mauritanian Upwelling and the Angola-Benguela Frontal zones off western Africa. Two of the three species in the Subpolar-Temperate group had bipolar distributions, and all three occurred in the Mediterranean and in the Mauritanian Upwelling zone. Most Central, Tropical and Western Tropical species were present in the in the Gulf of Mexico. The 10 species from the Mediterranean were a mixture of Subpolar-Temperate, Central and benthopelagic species. Patterns of distribution in Atlantic pelagic

  4. 60. NORTHEASTERN VIEW OF THE REMAINS OF THE DOROTHY SIX ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    60. NORTHEASTERN VIEW OF THE REMAINS OF THE DOROTHY SIX BLAST FURNACE COMPLEX. (Martin Stupich) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  5. 55. GENERAL NORTHEASTERN VIEW OF DOROTHY SIX BLAST FURNACE COMPLEX ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    55. GENERAL NORTHEASTERN VIEW OF DOROTHY SIX BLAST FURNACE COMPLEX WITH LADLE HOUSE AND IRON DESULPHERIZATION BUILDING ON RIGHT. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  6. 43. NORTHEASTERN VIEW OF MOULD CONDITIONING BUILDING AND BOP SHOP, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    43. NORTHEASTERN VIEW OF MOULD CONDITIONING BUILDING AND BOP SHOP, WITH OPEN HEARTH No. 2 BUILDING ON LEFT. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  7. 14. NORTHEASTERN VIEW OF ORIGINAL DEMAG AIR COMPRESSOR UNIT FOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. NORTHEASTERN VIEW OF ORIGINAL DEMAG AIR COMPRESSOR UNIT FOR THE LINDE 1000 TONS PER DAY HIGH PURITY OXYGEN MAKING PLANT. - U.S. Steel Duquesne Works, Fuel & Utilities Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  8. Landscape Thresholds and the Condition of Northeastern Estuaries

    EPA Science Inventory

    Anthropogenic impacts to northeastern estuaries have been well documented and many researchers have quantified the associations between broad scale human land uses in contributing landscapes and impacted estuarine condition. However, associations alone are not adequate for ident...

  9. 3. NORTHEASTERN VIEW OF THE ROCK CREEK AND POTOMAC PARKWAY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. NORTHEASTERN VIEW OF THE ROCK CREEK AND POTOMAC PARKWAY RAMP. VIEW TAKEN FROM NORTHERN RAILING OF MEMORIAL BRIDGE. - Arlington Memorial Bridge, Watergate & Bridge Plaza, Adjacent to Arlington Memorial Bridge & Lincoln Memorial, Washington, District of Columbia, DC

  10. IS NITROGEN DEPOSITION ALTERING THE NITROGEN STATUS OF NORTHEASTERN FORESTS?

    EPA Science Inventory

    This paper reviews literature and compiles existing data to address the question "Is N deposition altering the N status in Northeastern forests?" Using correlational techniques and large sample size, three different categories of indicators appear to give different results. The...

  11. Changes in Hadley Circulation, Azores High and Winter Precipitation over East Africa

    NASA Astrophysics Data System (ADS)

    Iqbal, M. J.; Hameed, S.

    2008-12-01

    We present a study of changes in winter precipitation over a region comprising Ethiopia, Kenya and Tanzania during 1952-2002. A persistent drying trend in addition to interannual variability is noted. Previously variability of precipitation in East Africa has been interpreted in terms of the North Atlantic Oscillation. Our results show that the centers of action approach, i.e., considering changes in the Azores High and the Icelandic low separately gives quantitatively improved explanation of changes in rainfall. The drying trend in East Africa is seen to be related to a strengthening as well as poleward displacement of the Azores High pressure system, which are attributed to changes in Hadley circulation over the North Atlantic.

  12. Dust generation and drought patterns in Africa from helium-4 in a modern Cape Verde coral

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, S.; Kreycik, P.

    2008-10-01

    We show that helium-4 (4He) concentrations in a modern Porites coral from Cape Verde provides a robust reconstruction of mineral dust loading over the Eastern Tropical Atlantic from mid-1950's to mid-1990's. The 4He record demonstrates pronounced increases in dust emission from North Africa associated with the severe droughts in the Sahel. Our record provides direct evidence that dust emission rates in the 1950's, prior to the onset of the Sahel droughts, were a factor of nine lower than during 1980-84. This large change in dust emission rate indicates global aerosol contents would have increased by ~45% over this period, which may have contributed to a reduction in solar radiation reaching the Earth's surface. We find that dust emission from North Africa is most closely related to drought patterns, rather than to changes in atmospheric circulation patterns resulting from climate oscillations, such as North Atlantic Oscillations and El Nino/Southern Oscillation.

  13. Pythiosis in Africa

    PubMed Central

    Rivierre, Christine; Laprie, Caroline; Guiard-Marigny, Olivier; Bergeaud, Patrick; Berthelemy, Madeleine

    2005-01-01

    We report the first case of pythiosis from Africa in an 8-month-old dog with a chronic and ulcerative cutaneous lesion. The etiologic agent belonged to the genus Pythium. Phylogenetic analysis placed the isolate in a sister group to the other P. insidiosum strains. However, the isolate may belong to a new Pythium species. PMID:15757572

  14. Photomontage. Water in Africa.

    ERIC Educational Resources Information Center

    McKoski, David

    The Water in Africa Project was realized over a 2-year period by a team of Peace Corps volunteers. As part of an expanded, detailed design, resources were collected from over 90 volunteers serving in African countries, photos and stories were prepared, and standards-based learning units were created for K-12 students. This unit, "Photomontage,"…

  15. Anglicising Postapartheid South Africa

    ERIC Educational Resources Information Center

    Louw, P. Eric

    2004-01-01

    The apartheid state deliberately encouraged linguistic diversity and actively built cultural infrastructures which impeded Anglicisation. With the end of apartheid has come "de facto" Anglicisation. So although South Africa has, since 1994, had 11 official languages, in reality, English is swamping the other 10 languages. Afrikaans has, in…

  16. Topical Research: Africa.

    ERIC Educational Resources Information Center

    Lynn, Karen

    This lesson plan can be used in social studies, language arts, or library research. The instructional objective is for students to select a topic of study relating to Africa, write a thesis statement, collect information from media sources, and develop a conclusion. The teacher may assign the lesson for written or oral evaluation. The teacher…

  17. Out of Africa

    ERIC Educational Resources Information Center

    Wilbert, Nancy Corrigan

    2009-01-01

    Karen Blixen (Isak Dinesen), author of "Out of Africa," said, "God made the world round so people would never be able to see too far down the road." The author embraced this wonderful thought by venturing on a three-week journey to Kenya and Tanzania in search of grand adventure. In this article, the author shares her adventure with her students…

  18. Africa: Myth and Reality.

    ERIC Educational Resources Information Center

    Brown, Barbara B.

    1994-01-01

    Reports on the Third International Social Studies Conference held in Nairobi, Kenya, in 1994. Discusses democracy, educational reform efforts, and the importance of tourism to the Kenyan economy. Asserts that U.S. teachers must use accurate and nonstereotypical instructional materials in teaching about Africa. (CFR)

  19. West and Central Africa.

    PubMed

    Lydie, N; Robinson, N J

    1998-01-01

    This article reviews scientific and other literature during the 1990s that links migration and mobility with the spread of sexually transmitted diseases (STDs), including HIV/AIDS. The focus is on key population groups linked to the spread of HIV and STDs in West and Central Africa: migrant laborers, truck drivers, itinerant traders, commercial sex workers (CSWs), and refugees. Countries with high emigration and immigration tend to have high levels of HIV infection, with the exception of Senegal. The main destination of immigrants are Senegal, Nigeria, and Cote d'Ivoire in West Africa and Cameroon, Congo, Gabon, and Congo in Central Africa. The risk of infection and the spread of HIV is variable among migrants. There is little in the literature that substantiates hypotheses about the strong association between migration and HIV-positive status. Information is needed on the duration, frequency of return visits, living conditions, sexual activities with multiple partners, and information before departure, along the routes, at final destination, and at the time of returns. Action-based research in five West African countries (Burkina Faso, Cote d'Ivoire, Mali, Niger, and Senegal) should produce results in late 1998. Comparable studies in Central Africa are unknown. Regional studies should be complemented by local studies. Prevention would benefit from studies on the relative size of these five population groups by geographic location.

  20. South Africa's Constitutional Change.

    ERIC Educational Resources Information Center

    Getman, Thomas

    1987-01-01

    Describes the striking dichotomy of South Africa's beauty and the squalor resulting from the apartheid policies of the government. Reviews reactions of black South Africans to recent constitutional changes and details efforts to secure more sweeping reform. Includes stories of several individuals who have taken actions which oppose the system of…

  1. Trends Abroad: South Africa

    ERIC Educational Resources Information Center

    Varley, Douglas H.

    1970-01-01

    In South Africa today there is a complex structure of laws and regulations which impose a variety of restrictions on individual liberties including the freedom to publish and read literary material. The successive steps by which this state of affairs has been reached are briefly described. (NH)

  2. Education in Africa.

    ERIC Educational Resources Information Center

    Educational Documentation and Information, 1977

    1977-01-01

    This selected, annotated bibliography of information resources in English and/or French is divided into sections on books; documents and articles; UNESCO publications; reference works; and African periodicals. A list of institutions concerned with education in Africa is included, as well as educational documentation and information services in…

  3. AED in Africa

    ERIC Educational Resources Information Center

    Academy for Educational Development, 2004

    2004-01-01

    Founded in 1961, the Academy for Educational Development (AED) is an independent, nonprofit, charitable organization that operates development programs in the United States and throughout the world. This directory presents an overview of the AED programs in Africa since 1975. Current AED Programs include: (1) HIV/AIDS Prevention and Impact…

  4. Neonatal surgery in Africa.

    PubMed

    Chirdan, Lohfa B; Ngiloi, Petronilla J; Elhalaby, Essam A

    2012-05-01

    The management of neonatal surgical problems continues to pose considerable challenges, particularly in low-resource settings. The burden of neonatal surgical diseases in Africa is not well documented. The characteristics of some neonatal surgical problems are highlighted. Late presentation coupled with poor understanding of the milieu interior of the neonates by incompetent health care providers and poorly equipped hospitals combine to give rise to the unacceptable high morbidity and mortality in most parts of Africa. Proper training of all staff involved in neonatal health care coupled with community awareness must be vigorously pursued by all stakeholders. Various governments throughout the continent of Africa, in conjunction with international donor agencies, must not only provide an adequate budget for health care services and improve infrastructures, but must also deliberately encourage and provide funding for neonatal surgical care and research across the continent. The well-established pediatric surgical training programs, particularly in North and South Africa, should hold the moral responsibility of training all possible numbers of young surgeons from other African countries that do not have any existing pediatric surgical training programs or those countries suffering from remarkable shortage of trained pediatric surgeons.

  5. Africa and Applied Linguistics.

    ERIC Educational Resources Information Center

    Makoni, Sinfree, Ed.; Meinhof, Ulrike H., Ed.

    2003-01-01

    This collection of articles includes: "Introducing Applied Linguistics in Africa" (Sinfree Makoni and Ulrike H. Meinhof); "Language Ideology and Politics: A Critical Appraisal of French as Second Official Language in Nigeria" (Tope Omoniyi); "The Democratisation of Indigenous Languages: The Case of Malawi" (Themba Moyo); "Classroom Code-Switching…

  6. Literacy in Francophone Africa.

    ERIC Educational Resources Information Center

    Kokora, Pascal D.

    1991-01-01

    Literacy in francophone Africa, where literacy is still a privilege, is reviewed in terms of the complex linguistic situation, effects of population change, concepts and definitions of literacy, promotion of literacy in adult nonformal settings (e.g., African language literacy materials, multilingual settings). (23 references) (LB)

  7. 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

  8. Decadal-Scale Tropical North Atlantic Climate Variability Recorded in Slow Growing Cape Verde Corals

    NASA Astrophysics Data System (ADS)

    Moses, C. S.; Swart, P. K.; Dodge, R. E.; Helmle, K. P.; Thorrold, S.

    2002-12-01

    The decadal to century scale climate variability of the tropical North Atlantic has major implications for both neighboring coastal and inland areas. Changes in patterns of sea surface temperature (SST) and SST anomalies (SSTA) in the tropical North Atlantic are known to affect rainfall in Florida, South America, and sub-Saharan Africa, as well as the number of major hurricanes formed in the Atlantic. Because of the significance of these connections, it is important to further increase our predictive capacity for the recognition of trends and cycles in tropical North Atlantic SST and SSTA. Located at 15° N latitude off the west coast of sub-Saharan Africa, the Cape Verde Islands are an ideal geographic location to search for records of the Tropical North Atlantic Index (TNA). Such patterns are present in proxy indicators of climate (O, C, Sr/Ca and Mg/Ca) recorded in the skeletons of slow growing corals, such as Siderastrea radians, found in Cape Verde (growth rate = 1-2 mm/yr). These corals represent an archive for SST and SSTA records that exceed the instrumental period of the eastern tropical North Atlantic. We cored corals from several different locations within the Cape Verde archipelago and analyzed them for stable isotopes (δ13C and δ18O) and minor elements (Sr, Mg, and Ba). The δ18O signal present in these corals shows a distinct relationship to the TNA over the better part of the last 100 years. In addition, the δ18O record in several of these corals also records the onset of the latest Sahel (11°-18° N in Africa) drought which began in 1970. The Sr/Ca and Mg/Ca records of these corals indicate a slight warming of the waters around Cape Verde during the last 100 years, as well as accurately recording the El Niño events of 1982-83 and 1997-98. The correlations present between the records in these corals and the known instrumental record for the eastern tropical North Atlantic suggests that the fluctuations recorded in the proxy indicators may be

  9. Short shrift for Africa.

    PubMed

    Collymore, Y

    1994-01-01

    The plan of action that emerged from the International Conference on Population and development (ICPD) held in Cairo in September 1994 did not directly address the major problems of pervasive poverty and dismal infant and maternal mortality rates in Africa. The Organization of African Unity met the week before ICPD to develop an integrated population and development strategy. The continent's population growth rate of 3% far exceeds that in most other developing countries; the maternal mortality rate is 640/100,000 live births vs. only 30 for industrialized countries. Its infant mortality rate is 114 deaths/1000 live births--double that of Western Europe. Africa's annual requirements under the Cairo plan for environmental, population, and development strategies would be $2.2-3 billion during 1995-2000. The estimated needs will grow to $4.3-5.6 billion by the year 2015. However, Botswana, Lesotho, Malawi, Mozambique, Namibia, Swaziland, and South Africa warned against these ambitious goals, preferring instead individual national targets. South Africa is compiling population data that indicate that the rate of growth is 2%/year with a current estimated population of 40 million. A population policy is being considered within the context of reconstruction and development. Namibia also faces a growing population that could compromise economic development. Some nongovernmental organizations have stated that the ICPD failed to confront unsafe abortions and reproductive health problems in an effort to appease the Vatican and Islamic countries. Women's reproductive and sexual rights have also been rejected by some Latin American and Islamic countries as alien to their laws and culture. Nevertheless, an agreement was reached on information and access to family planning services for teenagers and counseling on responsible sexual behavior. There were also charges from African delegates about diverting attention from the internecine conflicts in Africa that have resulted in

  10. Multi-velocity, multi-directional extension in the South Atlantic rift

    NASA Astrophysics Data System (ADS)

    Heine, Christian; Brune, Sascha; Zoethout, Jasper; Dietmar Müller, R.

    2013-04-01

    Integrated plate kinematic and forward extensional modelling provides new and powerful insights into the evolution of conjugate passive margin systems. The South Atlantic conjugate margins are an ideal laboratory as intracontinental rifting in Africa and South America preceeding the opening of the South Atlantic rift allows to quantitatively reconstruct the kinematics of the pre-seafloor spreading extensional phase. We utilise a self-consistent, high resolution plate kinematic model which includes deforming plates to analyse the spatio-temporal evolution of rifting in the South Atlantic and Equatorial rift system and relate our findings to margin geometry and volcanism. We find that the South Atlantic Rift initiates with a slow extension velocity that persists over ~20 My followed by rapid plate acceleration whereby the extension rate increases ten-fold during few million years to final sea-floor spreading velocities. Simultaneously, the plate motion vector of the South American plate experiences strong counter-clockwise rotation. We further combine our plate kinematic models with forward numerical models of lithosphere extension to investigate the effects of a multi-velocity, multi-directional extensional history on the dynamics of lithosphere deformation. Our results illustrate the spatio-temporal variability of breakup, extension and margin geometry along the South Atlantic and Equatorial rift systems.

  11. A clinico-epidemiological study of epidemic typhus in Africa.

    PubMed

    Perine, P L; Chandler, B P; Krause, D K; McCardle, P; Awoke, S; Habte-Gabr, E; Wisseman, C L; McDade, J E

    1992-05-01

    Epidemic, louse-borne typhus persists in the rugged, mountainous areas of Ethiopia and much of northeastern and central Africa as well as in the rural highlands of Central and South America, where the conditions of living favor the harboring of body lice and where antibiotic treatment and effective louse-control measures are unavailable. The historical significance and current epidemiology of typhus, including the reservoir of Rickettsia prowazekii in flying squirrels in the United States, are reviewed, and the clinical presentation, laboratory findings, and hospital course in the cases of 60 patients admitted with epidemic, louse-borne typhus to the St. Paul's Hospital in Addis Ababa, Ethiopia, are described. Treatment of this disease with oral doxycycline, tetracycline, or chloramphenicol prevents complications and results in prompt resolution of symptoms. PMID:1600020

  12. Boninites: Characteristics and tectonic constraints, northeastern Appalachians

    USGS Publications Warehouse

    Kim, J.; Jacobi, R.D.

    2002-01-01

    Boninites are high Mg andesites that are thought to form in suprasubduction zone tectonic environments as primary melts from refractory mantle. Boninites provide a potential constraint on tectonic models for ancient terranes that contain boninites because the only unequivocal tectonic setting in which "modern" boninites have been recognized is a fore-arc setting. Tectonic models for "modern" boninite genesis include subduction initiation ("infant arc"), fore-arc spreading, and the forearc side of intra-arc rifting (spreading). These models can be differentiated by the relative age of the boninites and to a lesser degree, geochemistry. The distinctive geochemistry of boninites promotes their recognition in ancient terranes. As detailed in this report, several mafic terranes in the northeastern Appalachians contain boninites; these terranes were situated on both sides of Iapetus. The characteristics of these boninites can be used to constrain tectonic models of the evolution of the northeastern Appalachians. On the Laurentian side of Iapetus, "infant arc" boninites were not produced ubiquitously during the Cambrian subduction initiation, unless sampling problems or minimum age dates obscure a more widespread boninite "infant arc". The Cambrian subduction initiation on the Laurentian side was probably characterized by both "infant arc" boninitic arc construction (perhaps the >496 Ma Hawley Formation and the >488 Ma Betts Cove Ophiolite) and "normal" arc construction (Mt. Orford). This duality is consistent with the suggestion that the pre-collisional geometry of the Laurentian margin was complex. The Bay of Islands Complex and Thetford Mines ophiolite boninites are likely associated with forearc/intra-arc spreading during the protracted evolution of the Cambrian arc system. The relatively young boninites in the Bronson Hill Arc suggest that the Taconic continuous eastward subduction tectonic model is less tenable than other models. On the Gondwana side of Iapetus, the

  13. Floods of June 2012 in northeastern Minnesota

    USGS Publications Warehouse

    Czuba, Christiana R.; Fallon, James D.; Kessler, Erich W.

    2012-01-01

    During June 19–20, 2012, heavy rainfall, as much as 10 inches locally reported, caused severe flooding across northeastern Minnesota. The floods were exacerbated by wet antecedent conditions from a relatively rainy spring, with May 2012 as one of the wettest Mays on record in Duluth. The June 19–20, 2012, rainfall event set new records in Duluth, including greatest 2-day precipitation with 7.25 inches of rain. The heavy rains fell on three major watersheds: the Mississippi Headwaters; the St. Croix, which drains to the Mississippi River; and Western Lake Superior, which includes the St. Louis River and other tributaries to Lake Superior. Widespread flash and river flooding that resulted from the heavy rainfall caused evacuations of residents, and damages to residences, businesses, and infrastructure. In all, nine counties in northeastern Minnesota were declared Federal disaster areas as a result of the flooding. Peak-of-record streamflows were recorded at 13 U.S. Geological Survey streamgages as a result of the heavy rainfall. Flood-peak gage heights, peak streamflows, and annual exceedance probabilities were tabulated for 35 U.S. Geological Survey streamgages. Flood-peak streamflows in June 2012 had annual exceedance probabilities estimated to be less than 0.002 (0.2 percent; recurrence interval greater than 500 years) for five streamgages, and between 0.002 and 0.01 (1 percent; recurrence interval greater than 100 years) for four streamgages. High-water marks were identified and tabulated for the most severely affected communities of Barnum (Moose Horn River), Carlton (Otter Creek), Duluth Heights neighborhood of Duluth (Miller Creek), Fond du Lac neighborhood of Duluth (St. Louis River), Moose Lake (Moose Horn River and Moosehead Lake), and Thomson (Thomson Reservoir outflow near the St. Louis River). Flood-peak inundation maps and water-surface profiles were produced for these six severely affected communities. The inundation maps were constructed in a

  14. Cholera outbreaks in Africa.

    PubMed

    Mengel, Martin A; Delrieu, Isabelle; Heyerdahl, Leonard; Gessner, Bradford D

    2014-01-01

    During the current seventh cholera pandemic, Africa bore the major brunt of global disease burden. More than 40 years after its resurgence in Africa in 1970, cholera remains a grave public health problem, characterized by large disease burden, frequent outbreaks, persistent endemicity, and high CFRs, particularly in the region of the central African Great Lakes which might act as reservoirs for cholera. There, cases occur year round with a rise in incidence during the rainy season. Elsewhere in sub-Saharan Africa, cholera occurs mostly in outbreaks of varying size with a constant threat of widespread epidemics. Between 1970 and 2011, African countries reported 3,221,050 suspected cholera cases to the World Health Organization, representing 46 % of all cases reported globally. Excluding the Haitian epidemic, sub-Saharan Africa accounted for 86 % of reported cases and 99 % of deaths worldwide in 2011. The number of cholera cases is possibly much higher than what is reported to the WHO due to the variation in modalities, completeness, and case definition of national cholera data. One source on country specific incidence rates for Africa, adjusting for underreporting, estimates 1,341,080 cases and 160,930 deaths (52.6 % of 2,548,227 estimated cases and 79.6 % of 209,216 estimated deaths worldwide). Another estimates 1,411,453 cases and 53,632 deaths per year, respectively (50 % of 2,836,669 estimated cases and 58.6 % of 91,490 estimated deaths worldwide). Within Africa, half of all cases between 1970 and 2011 were notified from only seven countries: Angola, Democratic Republic of the Congo, Mozambique, Nigeria, Somalia, Tanzania, and South Africa. In contrast to a global trend of decreasing case fatality ratios (CFRs), CFRs have remained stable in Africa at approximately 2 %. Early propagation of cholera outbreaks depends largely on the extent of individual bacterial shedding, host and organism characteristics, the likelihood of people coming into contact with

  15. Sea-level fluctuations show Ocean Circulation controls Atlantic Multidecadal Variability

    NASA Astrophysics Data System (ADS)

    McCarthy, Gerard; Haigh, Ivan; Hirschi, Joel; Grist, Jeremy; Smeed, David

    2015-04-01

    We present observational evidence that ocean circulation controls the decadal evolution of heat content and consequently sea-surface temperatures (SST) in the North Atlantic. One of the most prominent modes of Atlantic variability is the Atlantic multidecadal oscillation (AMO) observed in SSTs. Positive (negative) phases of the AMO are associated with warmer (cooler) SSTs. Positive phases of the AMO have been linked with decadal climate fluctuations including increased summer precipitation in Europe; increased northern hemisphere land temperatures, fewer droughts in the Sahel region of Africa and increased Atlantic hurricane activity. It is widely believed that the Atlantic circulation controls the phases of the AMO by controlling the decadal changes in heat content in the North Atlantic. However, due to the lack of ocean circulation observations, this link has not been previously proven. We present a new interpretation of the sea-level gradient along to the east coast of the United States to derive a measure of ocean circulation spanning decadal timescales. We use this to estimate heat content changes that we validate against direct estimates of heat content. We use the longevity of the tide gauge record to show that circulation, as interpreted in sea-level gradient changes, drives the major transitions in the AMO since the 1920's. We show that the North Atlantic Oscillation is highly correlated with this sea-level gradient, indicating that the atmosphere drives the circulation changes. The circulation changes are essentially integrated by the ocean in the form of ocean heat content and returned to the atmosphere as the AMO. An additional consequence of our interpretation is that recently reported accelerations in sea-level rise along the US east coast are consistent with a declining AMO that has been predicted by a number of authors.

  16. Latest Jurassic-early Cretaceous regressive facies, northeast Africa craton

    SciTech Connect

    van Houten, F.B.

    1980-06-01

    Nonmarine to paralic detrital deposits accumulated in six large basins between Algeria and the Arabo-Nubian shield during major regression in latest Jurassic and Early Cretaceous time. The Ghadames Sirte (north-central Libya), and Northern (Egypt) basins lay along the cratonic margin of northeastern Africa. The Murzuk, Kufra, and Southern (Egypt) basins lay in the south within the craton. Data for reconstructing distribution, facies, and thickness of relevant sequences are adequate for the three northern basins only. High detrital influx near the end of Jurassic time and in mid-Cretaceous time produced regressive nubian facies composed largely of low-sinuosity stream and fahdelta deposits. In the west and southwest the Ghadames, Murzuk, and Kufra basins were filled with a few hundred meters of detritus after long-continued earlier Mesozoic aggradation. In northern Egypt the regressive sequence succeeded earlier Mesozoic marine sedimentation; in the Sirte and Southern basins correlative deposits accumulated on Precambrian and Variscan terranes after earlier Mesozoic uplift and erosion. Waning of detrital influx into southern Tunisia and adjacent Libya in the west and into Israel in the east initiated an Albian to early Cenomanian transgression of Tethys. By late Cenomanian time it had flooded the entire cratonic margin, and spread southward into the Murzuk and Southern basins, as well as onto the Arabo-Nubian shield. Latest Jurassic-earliest Cretaceous, mid-Cretaceous, and Late Cretaceous transgressions across northeastern Africa recorded in these sequences may reflect worldwide eustatic sea-level rises. In contrast, renewed large supply of detritus during each regression and a comparable subsidence history of intracratonic and marginal basins imply regional tectonic control. 6 figures.

  17. 78 FR 59878 - Atlantic Highly Migratory Species; Commercial Atlantic Aggregated Large Coastal Shark (LCS...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-30

    ... management groups is closed, even across fishing years. On July 3, 2013 (78 FR 40318), NMFS announced the... Species; Commercial Atlantic Aggregated Large Coastal Shark (LCS), Atlantic Hammerhead Shark, Atlantic Blacknose Shark, and Atlantic Non-Blacknose Small Coastal Shark (SCS) Management Groups AGENCY:...

  18. The Inter-Tropical Convergence Zone: A causal mechanism for Pb isotope cyclicity in Tropical Atlantic sediment cores

    NASA Astrophysics Data System (ADS)

    Abouchami, W.; Zabel, M.

    2003-04-01

    Lead isotopic compositions of bulk sediment cores from the Tropical Atlantic can be used to infer variations in the provenance of terrigenous input to the Tropical Atlantic during Pleistocene climate cycles. Pb isotope data were obtained using the triple spike method (Galer, 1999) on bulk sediments cores and cover the last six Marine Isotope Stages. The 200-ka high precision (2σ ˜100 ppm) Pb isotope records of the Ceará Rise (Western Atlantic, core GeoB1523-1, 3^o49'N, 41^o37'W, 3292 m) and Sierra Leone Rise (Eastern Atlantic, core GeoB2910-1, 4^o50'N, 21^o03'W, 2703 m) cores show a clear glacial-interglacial cyclicity, reflected by alternating unradiogenic Pb and radiogenic Pb. Changes in the relative proportions of the glacial (unradiogenic) and interglacial (radiogenic) Pb source(s) can be explained by changes in the erosional regime (chemical vs. physical) as a function of prevailing climate, combined with different mechanisms of Pb transport to the oceans (predominantly eolian in the Eastern Atlantic vs. riverine in the Western Atlantic). We interpret these regional changes as reflecting shifts in the mean latitude of the Inter-Tropical Convergence Zone that affects the hydrological cycle over South America and the wind systems over Africa. Our results strongly favor an increase in winter wind transport (rather than glacial hyper aridity) as the cause of enhanced glacial terrigenous fluxes observed in the Tropical Atlantic (Ruddiman, 1997). The two Atlantic Pb isotopic records exhibit strong correlations with Pleistocene sea level fluctuations, providing evidence for global teleconnection between tropical records and high latitude climate. Galer, S.J.G. (1999). Optimal double and triple spiking for high precision lead isotopic measurements. Chem. Geol. 154, 255-274. Ruddiman, W. F. (1997). Tropical Atlantic terrigenous fluxes since 25,000 yrs B.P., Mar. Geol., 136, 189-207.

  19. Phylogenetic analysis in Myrcia section Aulomyrcia and inferences on plant diversity in the Atlantic rainforest

    PubMed Central

    Staggemeier, Vanessa Graziele; Diniz-Filho, José Alexandre Felizola; Forest, Félix; Lucas, Eve

    2015-01-01

    Background and Aims Myrcia section Aulomyrcia includes ∼120 species that are endemic to the Neotropics and disjunctly distributed in the moist Amazon and Atlantic coastal forests of Brazil. This paper presents the first comprehensive phylogenetic study of this group and this phylogeny is used as a basis to evaluate recent classification systems and to test alternative hypotheses associated with the history of this clade. Methods Fifty-three taxa were sampled out of the 120 species currently recognized, plus 40 outgroup taxa, for one nuclear marker (ribosomal internal transcribed spacer) and four plastid markers (psbA-trnH, trnL-trnF, trnQ-rpS16 and ndhF). The relationships were reconstructed based on Bayesian and maximum likelihood analyses. Additionally, a likelihood approach, ‘geographic state speciation and extinction’, was used to estimate region- dependent rates of speciation, extinction and dispersal, comparing historically climatic stable areas (refugia) and unstable areas. Key Results Maximum likelihood and Bayesian inferences indicate that Myrcia and Marlierea are polyphyletic, and the internal groupings recovered are characterized by combinations of morphological characters. Phylogenetic relationships support a link between Amazonian and north-eastern species and between north-eastern and south-eastern species. Lower extinction rates within glacial refugia suggest that these areas were important in maintaining diversity in the Atlantic forest biodiversity hotspot. Conclusions This study provides a robust phylogenetic framework to address important ecological questions for Myrcia s.l. within an evolutionary context, and supports the need to unite taxonomically the two traditional genera Myrcia and Marlierea in an expanded Myrcia s.l. Furthermore, this study offers valuable insights into the diversification of plant species in the highly impacted Atlantic forest of South America; evidence is presented that the lowest extinction rates are found inside

  20. Hongshan chiefly communities in Neolithic northeastern China

    PubMed Central

    Peterson, Christian E.; Lu, Xueming; Drennan, Robert D.; Zhu, Da

    2010-01-01

    The Hongshan societies of northeastern China are among East Asia’s earliest complex societies. They have been known largely from elaborate burials with carved jades in ceremonial platforms. The most monumental remains are concentrated in a “core zone” in western Liaoning province. Residential remains are less well known and most investigations of them have been in peripheral regions outside the core zone. Recent regional settlement pattern research around the well known ceremonial site of Dongshanzui has begun to document the communities that built and used Hongshan core zone monuments and to assess their developmental dynamics. The core zone, like the Hongshan periphery, appears to have been organized into a series of small chiefly districts within which ceremonial activities were important integrative forces. Their estimated populations of less than 1,000 are not much larger than those of districts in the periphery, and the evidence does not suggest that these districts were integrated into any larger political entity. The greater elaboration of core zone monumental architecture is thus not attributable to demographically larger communities or to larger-scale political integration. Future research should focus on documenting the organization of statuses and economic activities within these core zone communities to assess potential differences from peripheral communities in these regards. PMID:20224038

  1. Filarioids infecting dogs in northeastern Brazil.

    PubMed

    Ramos, Rafael Antonio Nascimento; de Oliveira do Rêgo, Ana Gabriela; de Farias Firmino, Everton Diogo; do Nascimento Ramos, Carlos Alberto; de Carvalho, Gílcia Aparecida; Dantas-Torres, Filipe; Otranto, Domenico; Alves, Leucio Câmara

    2016-08-15

    Species of filarial nematodes belonging to the genera Dirofilaria and Acanthocheilonema are recognised as common parasites of dogs throughout the world. Recently, other filarioids featured by the presence of dermal microfilariae (e.g., Onchocerca lupi and Cercopithifilaria spp.) have been recognised in Europe. In Brazil, reports of filarioids in dogs are limited to Dirofilaria immitis, Acanthocheilonema reconditum and Cercopithifilaria bainae. To investigate the distribution of filarial infections in dogs living in an endemic region from northeastern Brazil, blood and skin samples (n=104) were microscopically (modified Knott's test and skin snip sediment examination) and molecularly evaluated. Twenty-two dogs (21.15%) were positive at microscopic and/or molecular examination for at least one filarioid species, with 21 (20.19%) animals positive for blood microfilariae at molecular and/or at microscopic examination. Microfilariae of D. immitis were detected in 12 (11.54%) animals, with co-infection of D. immitis and A. reconditum observed in four (3.85%) individuals. One animal was positive for C. bainae at both microscopic and molecular examination. Analysis of sequence obtained in the present study showed significant alignment identity with that of C. bainae from Europe. Considering that in the area of study arthropod vectors (mosquitoes, fleas and ticks) are prevalent throughout the year, preventive measures should be disposed in order to avoid the animal infestation and pathogen infection. PMID:27514878

  2. A palaeomagnetic reconnaissance of northeastern Baluchistan, Pakistan

    NASA Astrophysics Data System (ADS)

    Klootwijk, Chris T.; Nazirullah, Russel; de Jong, Kees A.; Ahmed, Habib

    1981-01-01

    A total of 560 samples from three areas in northeastern Baluchistan (the southern Sulaiman Range, the central Loralai Range, and the northern Kirthar Range) were analyzed using thermal demagnetization techniques. Thirteen formations of late Palaeozoic to early Tertiary age were studied palaeomagnetically. Inclinations of the obtained results show a general affinity with the Indian apparent polar wander path. Deviating declinations from the Loralai Range indicate a clockwise rotation over 50° with respect to the Indian shield. Secondary magnetization components probably of late Palaeocene to early Eocene age were consistently present in the samples from the Kirthar Range and the Sulaiman Range but were not observed in samples from the Loralai Range. Acquisition of these components is attributed to crustal upwarping during the Palaeocene, which is tentatively related to initial collision of continental Indo-Pakistan with an island arc off south central Asia. The Baluchistan data support recent palaeomagnetic results from the Indus-Tsangpo suture zone in Ladakh (NW Himalaya), which indicate that such an initial collision took place at very low northern palaeolatitudes.

  3. Filarioids infecting dogs in northeastern Brazil.

    PubMed

    Ramos, Rafael Antonio Nascimento; de Oliveira do Rêgo, Ana Gabriela; de Farias Firmino, Everton Diogo; do Nascimento Ramos, Carlos Alberto; de Carvalho, Gílcia Aparecida; Dantas-Torres, Filipe; Otranto, Domenico; Alves, Leucio Câmara

    2016-08-15

    Species of filarial nematodes belonging to the genera Dirofilaria and Acanthocheilonema are recognised as common parasites of dogs throughout the world. Recently, other filarioids featured by the presence of dermal microfilariae (e.g., Onchocerca lupi and Cercopithifilaria spp.) have been recognised in Europe. In Brazil, reports of filarioids in dogs are limited to Dirofilaria immitis, Acanthocheilonema reconditum and Cercopithifilaria bainae. To investigate the distribution of filarial infections in dogs living in an endemic region from northeastern Brazil, blood and skin samples (n=104) were microscopically (modified Knott's test and skin snip sediment examination) and molecularly evaluated. Twenty-two dogs (21.15%) were positive at microscopic and/or molecular examination for at least one filarioid species, with 21 (20.19%) animals positive for blood microfilariae at molecular and/or at microscopic examination. Microfilariae of D. immitis were detected in 12 (11.54%) animals, with co-infection of D. immitis and A. reconditum observed in four (3.85%) individuals. One animal was positive for C. bainae at both microscopic and molecular examination. Analysis of sequence obtained in the present study showed significant alignment identity with that of C. bainae from Europe. Considering that in the area of study arthropod vectors (mosquitoes, fleas and ticks) are prevalent throughout the year, preventive measures should be disposed in order to avoid the animal infestation and pathogen infection.

  4. Temperature mediated moose survival in Northeastern Minnesota

    USGS Publications Warehouse

    Lenarz, M.S.; Nelson, M.E.; Schrage, M.W.; Edwards, A.J.

    2009-01-01

    The earth is in the midst of a pronounced warming trend and temperatures in Minnesota, USA, as elsewhere, are projected to increase. Northern Minnesota represents the southern edge to the circumpolar distribution of moose (Alces alces), a species intolerant of heat. Moose increase their metabolic rate to regulate their core body temperature as temperatures rise. We hypothesized that moose survival rates would be a function of the frequency and magnitude that ambient temperatures exceeded the upper critical temperature of moose. We compared annual and seasonal moose survival in northeastern Minnesota between 2002 and 2008 with a temperature metric. We found that models based on January temperatures above the critical threshold were inversely correlated with subsequent survival and explained >78 of variability in spring, fall, and annual survival. Models based on late-spring temperatures also explained a high proportion of survival during the subsequent fall. A model based on warm-season temperatures was important in explaining survival during the subsequent winter. Our analyses suggest that temperatures may have a cumulative influence on survival. We expect that continuation or acceleration of current climate trends will result in decreased survival, a decrease in moose density, and ultimately, a retreat of moose northward from their current distribution.

  5. Atlantic Seaduck Project

    USGS Publications Warehouse

    Perry, M.C.; Hanson, Alan; Kerekes, Joseph; Paquet, Julie

    2006-01-01

    Atlantic Seaduck Project is being conducted to learn more about the breeding and moulting areas of seaducks in northern Canada and more about their feeding ecology on wintering areas, especially Chesapeake Bay. Satellite telemetry is being used to track surf scoters wintering in Chesapeake Bay, Maryland and black scoters on migrational staging areas in New Brunswick, Canada to breeding and moulting areas in northern Canada. Various techniques used to capture the scoters included mist netting, night-lighting, and net capture guns. All captured ducks were transported to a veterinary hospital where surgery was conducted following general anaesthesia procedures. A PTT100 transmitter (39 g) manufactured by Microwave, Inc., Columbia, Maryland was implanted into the duck?s abdominal cavity with an external (percutaneous) antenna. Eight of the surf scoters from Chesapeake Bay successfully migrated to possible breeding areas in Canada and all 13 of the black scoters migrated to suspected breeding areas. Ten of the 11 black scoter males migrated to James Bay presumably for moulting. Updated information from the ARGOS Systems aboard the NOAA satellites on scoter movements was made accessible on the Patuxent Website. Habitat cover types of locations using GIS (Geographical Information Systems) and aerial photographs (in conjunction with remote sensing software) are currently being analyzed to build thematic maps with varying cosmetic layer applications. Many factors related to human population increases have been implicated in causing changes in the distribution and abundance of wintering seaducks. Analyses of the gullet (oesophagus and proventriculus) and the gizzard of seaducks are currently being conducted to determine if changes from historical data have occurred. Scoters in the Bay feed predominantly on the hooked mussel and several species of clams. The long-tailed duck appears to select the gem clam in greater amounts than other seaducks, but exhibits a diverse diet of

  6. Compound-specific isotopic analyses track changes in seasonal precipitation regimes in the Northeastern United States at ca 8200 cal yr BP

    NASA Astrophysics Data System (ADS)

    Shuman, Bryan; Huang, Yongsong; Newby, Paige; Wang, Yi

    2006-11-01

    We analyzed the hydrogen isotopic composition of sedimentary leaf wax (C 28n-acid) and palmitic acid (C 16n-acid) in cores from Berry and Crooked Ponds in Massachusetts. The results show a dramatic positive shift in leaf wax δD values around 8200 cal yr BP, when regional lake levels rose and plant communities shifted in favor of plants intolerant of dry conditions. To aid our interpretation, we studied modern lake sediment samples and found that the δD values of leaf wax and palmitic acid record the hydrogen isotopic composition of water available during the synthesis of these compounds. Palmitic acid δD values follow lake water values often derived from winter precipitation, and leaf wax δD values track the water available to terrestrial plants during the growing season. Based on these results, we interpret the downcore isotopic shift as an increase in the fraction of precipitation falling during the growing season. The increase coincides with evidence from pollen and palmitic acid δD values for a multi-century period of cold conditions at ca 8200 cal yr BP. The close timing of the brief cool period and a step-change in summer precipitation levels in the northeastern United States is consistent with the hypothesis that the collapse of the Laurentide ice sheet occurred in association with cold North Atlantic conditions from 8400 to 8000 cal yr BP. The location of the northeastern US downwind of the ice sheet and close to the North Atlantic makes it sensitive to both factors. Our results also provide insight into later changes in the northeastern US because they indicate a progressive decrease in summer precipitation levels after ca 8000 cal yr BP.

  7. Effects of orbital-scale ITCZ fluctuations on the mid Cretaceous tropical Atlantic region

    NASA Astrophysics Data System (ADS)

    Hofmann, P.; Beckmann, B.; Flögel, S.; Wagner, T.

    2009-04-01

    Shifts of the Inter Tropic Convergence Zone (ITCZ) on Milankovitch time scales have profound effects on the climate-ocean system of tropical regions. Changes in wind systems, regional hydrology and continental runoff linked to past fluctuations of the ITCZ are well known to have triggered a complex chain of forcing and feedback mechanisms between the regional biosphere and geosphere. In our study we explore these relationships for the mid-Cretaceous super-greenhouse. We present proxy records from two regions of the Coniacian tropical Atlantic, ODP Site 959 (West Africa off Ivory Coast) and ODP Site 1261 (Northern South America off Suriname) and compare them with results of GENESIS Atmospheric General Circulation modeling. Our data suggest that bioproductivity in the eastern tropical Atlantic mainly followed a precession controlled cyclic pattern which was closely linked to changes in nutrient and freshwater supply via continental runoff from the African continent. Different from that bioproductivity in the western tropical Atlantic shows a strong obliquity and eccentricity cycle pattern. We propose that these differences in the west were mainly caused by fluctuations in wind-driven upwelling off northern South America with a constant and high supply of nutrients from the continent maintaining the ocean redox system anoxic without interruption. Bioproductivity from wind-driven upwelling in the west would have pushed the water column into repetitive sulfidic conditions (euxinia), as confirmed by geochemical evidence. Overall bioproductivity east and west of the tropical Atlantic was high supporting deposition of extensive black shale deposits. The observed differences in depositional patterns on both sides of the Coniacian tropical Atlantic support that (orbital-driven) fluctuations of the ITCZ were mainly responsible, with strong contrasts in regional moisture distribution over Africa and South America and local strengthening of the trade wind system causing

  8. Mid-Cretaceous polar standstill of the Americas and motion of the Atlantic hotspots

    NASA Astrophysics Data System (ADS)

    Somoza, R.

    2008-05-01

    The hotspot (HS) fixity axiom installed early in the plate tectonics as an attractive toll for geodynamic analyzes. In particular, a mid-Cretaceous discrepancy between fixed Indo-Atlantic hotspot and paleomagnetic reference frames has been interpreted as evidence for true polar wander (TPW). Recent paleomagnetic findings (C.B. Zaffarana, this session) indicate that the Americas rotated (with different angular rates) about the spin axis between 125 and at least 100 Ma. This kinematic-paleogeographic scenario points to failure of the above mentioned TPW hypothesis, suggesting that the mid-Cretaceous HS-paleomagnetic discrepancy is related to motion of the Atlantic hotspots. On the other hand, dated outcrops and seamounts in the >2000 km White Mountains - New England trail define a tight cluster with no clear age progression when observed in African coordinates, suggesting that the sub-lithospheric melting anomaly responsible for the New England chain moved little with respect to Africa between 120 and 80 Ma. However, small circles centered in the feeder of the New England seamounts as seen from Africa misfit the 120-80 Ma trend of the Walvis ridge in the African South Atlantic, arguing for ~1 cm/yr inter-Atlantic HS motion, which in turn represents about 30 % the rate of coeval full spreading in the Central Atlantic. These observations suggest that a scenario where sub-lithospheric melting anomalies move and deform in concert with flow in the surrounding mantle needs to be allowed for assaying tectonic and geodynamic models. In agreement with this, reconstruction of Cretaceous poles from the Americas with respect to the moving-hotspot framework developed by O´Neill et al. (G3 6 (4), 2005) reduced to a half the paleopole-spin axis offset observed in fixed-HS coordinates (R. Somoza and C.B. Zaffarana, EPSL, in revision), with the residual offset being similar than that is found when large datasets of Cenozoic poles are observed in moving-HS coordinates.

  9. Internet Performance to Africa

    SciTech Connect

    Cottrell, L

    2003-10-01

    We report the first results ever for real-time Internet performance to Africa using the PingER methodology. Multiple monitoring hosts were used to enable comparisons with performance from different parts of the world. From these preliminary measurements, we have found that Internet packet losses to some African sites in recent months range from very poor to bad (> 12%), some getting better, others are holding steady or getting worse. This, together with the average monthly Round Trip Times, imply end-to-end maximum TCP throughputs that are order of magnitudes different between countries in the region. Africa is shown to be far from the Internet performance in industrialized nations due to the poor infrastructure in place today. These monitoring efforts can provide valuable information to analyze the relative rates of future improvement and today they help us to quantify the digital divide and can provide quantitative information to policy makers.

  10. This Is Africa.

    PubMed

    Verlo, April R; Bailey, Hugh H; Cook, Martin R

    2015-01-01

    Military deployments will always result in exposure to health hazards other than those from combat operations. The occupational and environmental health and endemic disease health risks are greater to the Special Operations Forces (SOF) deployed to the challenging conditions in Africa than elsewhere in the world. SOF are deployed to locations that lack life support infrastructures that have become standard for most military deployments; instead, they rely on local resources to sustain operations. Particularly, SOF in Africa do not generally have access to advanced diagnostic or monitoring capabilities or to medical treatment in austere locations that lack environmental or public health regulation. The keys to managing potential adverse health effects lie in identifying and documenting the health hazards and exposures, characterizing the associated risks, and communicating the risks to commanders, deployed personnel, and operational planners.

  11. Cenozoic siliciclastic sediment budget at continent-scale, Africa.

    NASA Astrophysics Data System (ADS)

    Guillocheau, François; Robin, Cécile; Calves, Gérôme; Baby, Guillaume

    2013-04-01

    Siliciclastic sediment budget measurements was performed along the margins and onshore basins of Africa for Cenozoic times. Our objective was first to quantify the ratio between onshore and offshore sediment preservation in the case of a relief with mostly no mountain belt and secondly to understand the factors forcing the sediment supply along the passive margins of Africa that can be long to very-long relief deformation (mantle dynamics, ridge push…) or climate changes (with the major aridification of Africa since Middle Miocene). This study is based on basin-scale regional sections (seismic reflection data from industry and academics, wells correlation), calibrated in age and lithology on different types of wells (industry, DSDP/ODP). Most of the effort was on the revaluation of the ages (calibration and uncertainties). The volumes of sediments and uncertainties on depth conversion velocity laws, lithology and ages were measured using software developed by J. Braun (Grenoble University, France). • The sediment preserved onshore (750 000 km3) is one of magnitude less than was is preserved offshore • The main deformations controlling the sediment supply are (1) the growth or the domes of the East African rift and (2) the marginal bulge of the central and equatorial segments of the South Atlantic Ocean (from southern Angola to Guinea). • The aridification of Africa since at least Middle Miocene is very sensitive in the south (fossilization of the relief of the South African Plateau) and in the northwest, with a sharp decrease of the sediment supply. • Some buffer effects are very important, for example for the Nile and the Zambezi, where sediments were first stored in onshore basins, Sudan or Malawi rift, and later drained because of a capture (Nile) or a regional stress change (Zambezi). Keywords: Africa, Cenozoic, Siliciclastic sediment fluxes, Deformation, Climate

  12. Climatic Variability over the North Atlantic

    NASA Astrophysics Data System (ADS)

    Hurrell, J.; Hoerling, M. P.; Folland, C. K.

    INTRODUCTION WHAT IS THE NORTH ATLANTIC OSCILLATION AND HOW DOES IT IMPACT REGIONAL - CLIMATE? WHAT ARE THE MECHANISMS THAT GOVERN NORTH ATLANTIC OSCILLATION VARIABILITY? Atmospheric Processes Ocean Forcing of the Atmosphere CONCLUDING COMMENTS ON THE OTHER ASPECTS OF NORTH ATLANTIC CLIMATE - VARIABILITY REFERENCES

  13. Terrorism in South Africa.

    PubMed

    MacFarlane, Campbell

    2003-01-01

    The Republic of South Africa lies at the southern tip of the African continent. The population encompasses a variety of races, ethnic groups, religions, and cultural identities. The country has had a turbulent history from early tribal conflicts, colonialisation, the apartheid period, and post-apartheid readjustment. Modern terrorism developed mainly during the apartheid period, both by activities of the state and by the liberation movements that continued to the time of the first democratic elections in 1994, which saw South Africa evolve into a fully representative democratic state with equal rights for all. Since 1994, terrorist acts have been criminal-based, evolving in the Cape Town area to political acts, largely laid at the feet of a predominantly Muslim organisation, People against Gangsterism and Drugs, a vigilant organisation allegedly infiltrated by Muslim fundamentalists. Along with this, has been terrorist activities, mainly bombings by disaffected members of white, right-wing groups. In the apartheid era, a Draconian series of laws was enacted to suppress liberation activities. After 1994, most of these were repealed and new legislation was enacted, particularly after the events of 11 September 2001; this legislation allows the government to act against terrorism within the constraints of a democratic system. Disaster management in South Africa has been largely local authority-based, with input from provincial authorities and Civil Defence. After 1994, attempts were made to improve this situation, and national direction was provided. After 11 September 2001, activity was increased and the Disaster Management Act 2002 was brought into effect. This standardized disaster management system at national, provincial, and local levels, also facilites risk assessment and limitation as well as disaster mitigation. The potential still exists for terrorism, mainly from right-wing and Muslim fundamentalist groups, but the new legislation should stimulate disaster

  14. Mozambique Coast, Africa

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The serene coastline of Mozambique (17.0S, 39.5E) Africa and the Indian Ocean offer some of the best beaches and recreational diving water in the world. Offshore reefs provide interesting coral formations that host a wide variety of marine life. Inland, the coastal savannas of this tropical nation are filled with a wide range of wildlife in some of the last animal refuges on the African continent.

  15. Lake Chad, Chad, Africa

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The fluctuating water levels of Lake Chad, (13.0N, 15.0E) at the intersection of the borders of Chad, Niger and Cameroon in the Sahara Desert, is an index of the drought in Africa. The lake level continues to decrease as indicated by the growing number and extent of emerging islands as previously submerged ancient sand dunes become visible. The water impounded between the dunes is probably because of local rainfall rather than a reversal of desertification.

  16. Atlantic opportunities for ENSO prediction

    NASA Astrophysics Data System (ADS)

    del Rey, Marta Martin; Rodríguez-Fonseca, Belén; Polo, Irene

    2015-04-01

    El Niño-Southern Oscillation (ENSO) is the dominant mode of tropical climate variability with worldwide impacts. Major advances in ENSO research have been done in the last decades, focusing on the mechanisms involved in its onset and development, as well as, its global climate teleconnections. Although modelling efforts have been made in ENSO forecast, the prediction of these episodes still remains a challenge for the scientific community. Recent studies put forward the role of extra-tropical and tropical regions as precursors of ENSO, but these teleconnections have changed along the 20th century. In particular, an Atlantic Niño precedes the development of a Pacific La Niña (and vice versa) 6 months in advance, taking part of an air-sea coupled mode of variability which only shows up during negative phases of the Atlantic Multidecadal Oscillation (AMO). The non-stationarity of this mode opens window opportunities for ENSO forecast, using the Tropical Atlantic Sea Surface Temperature (SST) as the predictor field. Here, we present for the first time a statistical crossvalidated hindcast of ENSO events based on an Extended Multiple Maximum Covariance Analysis (EMMCA). This method considers a unique predictor field, the summer Atlantic SSTs, and a set of predictant fields in different regions and seasons, according to the Atlantic-Pacific mechanism. The predicted tropical Pacific variables involved in ENSO development, show a good agreement with the observed ones during negative AMO phases, with a remarkable increase of the predictability skill based on correlations. During those negative AMO decades, the hindcast reproduces quite well the observed Atlantic-modulated ENSO episodes, but with stronger signal than observations. This AMO-dependency of the ENSO predictability could help to resolve some open questions about the seasonal to decadal ENSO forecast and its impacts.

  17. Astrophysics in Southern Africa

    NASA Astrophysics Data System (ADS)

    Whitelock, Patricia

    2008-03-01

    The government of South Africa has identified astronomy as a field in which their country has a strategic advantage and is consequently investing very significantly in astronomical infrastructure. South Africa now operates a 10-m class optical telescope, the Southern African Large Telescope (SALT), and is one of two countries short listed to host the Square Kilometre Array (SKA), an ambitious international project to construct a radio telescope with a sensitivity one hundred times that of any existing telescope. The challenge now is to produce an indigenous community of users for these facilities, particularly from among the black population which was severely disadvantaged under the apartheid regime. In this paper I briefly describe the observing facilities in Southern Africa before going on to discuss the various collaborations that are allowing us to use astronomy as a tool for development, and at the same time to train a new generation of astronomers who will be well grounded in the science and linked to their colleagues internationally.

  18. Drought in West Africa

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Drought settled over West Africa's Ivory Coast region when wet season rains came late in 2007. Instead of beginning in February, the rainy season didn't start until March, and steady rains didn't start until late March, said the Famine Early Warning System Network. Though the rain had started to alleviate the drought, vegetation was still depressed in parts of Cote d'Ivoire (Ivory Coast) between March 22 and April 6, 2007, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured the data used to make this image. The image shows current vegetation conditions compared to average conditions recorded since 2000. Areas where plants are growing more slowly or more sparsely than average are brown, while areas where vegetation is denser than average are green. The brown tint that dominates the image indicates that plants through most of the country are more sparse than normal. Among the crops affected by the lack of rain was West Africa's cocoa crop. About 70 percent of the world's cocoa comes from West Africa, and Cote d'Ivoire is a top grower, said Reuters. Cocoa prices climbed as the crop fell short. Farmers called the drought the worst in living memory, Reuters said. The delay in rainfall also led to water shortages in parts of Cote d'Ivoire, according to the United Nations Office for the Coordination of Humanitarian Affairs.

  19. On the North Atlantic Circulation

    NASA Astrophysics Data System (ADS)

    Schmitz, William J.; McCartney, Michael S.

    1993-02-01

    A new, speculative, and, we hope, provocative summary of the North Atlantic circulation is described, including both horizontal currents (wind-driven) and the primarily (thermohaline) meridional flows that involve the transformation of warm to cold water at high latitudes. Our picture is based on a synthesis of a variety of independent investigations that are contained in the literature as opposed to a presentation of the results of one technique or the point of view of one author. We describe a thermohaline cell (the so-called thermohaline conveyor belt) that is concentrated within the Atlantic and Southern oceans (rather than essentially global), with the most important upwelling sites being in the circumpolar and the equatorial current regimes. We concentrate on deep water formation and its replacement relative to intermediate-water formation. It has been pointed out recently that the formation of 13 Sv (1 Sv = 106 m³ s-1) of southward flowing North Atlantic Deep Water is compensated for in the upper ocean by northward cross-equatorial transport. We suggest that this thermocline layer flow passes through the Straits of Florida, transits the Gulf Stream system on its inshore side, and exits through the North Atlantic Current system after recirculation and modification. There is now a clear observational basis for the structure of recirculating gyres on the southern and northern sides of the Gulf Stream. We suggest a recirculation for the North Atlantic Current as well. We also describe a C-shaped component to the southern Gulf Stream recirculation and identify a roughly 10-Sv circulation in the eastern North Atlantic associated with the Azores Current. Recirculations play an important role in deep boundary current regimes and in water mass formation and modification. The transport of the deep western and northern boundary currents in the North Atlantic Ocean may be boosted (roughly doubled or tripled) by counterclockwise recirculating gyres and by additions of

  20. Downscaling GISS ModelE Boreal Summer Climate over Africa

    NASA Technical Reports Server (NTRS)

    Druyan, Leonard M.; Fulakeza, Matthew

    2015-01-01

    The study examines the perceived added value of downscaling atmosphere-ocean global climate model simulations over Africa and adjacent oceans by a nested regional climate model. NASA/Goddard Institute for Space Studies (GISS) coupled ModelE simulations for June- September 1998-2002 are used to form lateral boundary conditions for synchronous simulations by the GISS RM3 regional climate model. The ModelE computational grid spacing is 2deg latitude by 2.5deg longitude and the RM3 grid spacing is 0.44deg. ModelE precipitation climatology for June-September 1998-2002 is shown to be a good proxy for 30-year means so results based on the 5-year sample are presumed to be generally representative. Comparison with observational evidence shows several discrepancies in ModelE configuration of the boreal summer inter-tropical convergence zone (ITCZ). One glaring shortcoming is that ModelE simulations do not advance the West African rain band northward during the summer to represent monsoon precipitation onset over the Sahel. Results for 1998-2002 show that onset simulation is an important added value produced by downscaling with RM3. ModelE Eastern South Atlantic Ocean computed sea-surface temperatures (SST) are some 4 K warmer than reanalysis, contributing to large positive biases in overlying surface air temperatures (Tsfc). ModelE Tsfc are also too warm over most of Africa. RM3 downscaling somewhat mitigates the magnitude of Tsfc biases over the African continent, it eliminates the ModelE double ITCZ over the Atlantic and it produces more realistic orographic precipitation maxima. Parallel ModelE and RM3 simulations with observed SST forcing (in place of the predicted ocean) lower Tsfc errors but have mixed impacts on circulation and precipitation biases. Downscaling improvements of the meridional movement of the rain band over West Africa and the configuration of orographic precipitation maxima are realized irrespective of the SST biases.

  1. Downscaling GISS ModelE boreal summer climate over Africa

    NASA Astrophysics Data System (ADS)

    Druyan, Leonard M.; Fulakeza, Matthew

    2015-11-01

    The study examines the perceived added value of downscaling atmosphere-ocean global climate model simulations over Africa and adjacent oceans by a nested regional climate model. NASA/Goddard Institute for Space Studies (GISS) coupled ModelE simulations for June-September 1998-2002 are used to form lateral boundary conditions for synchronous simulations by the GISS RM3 regional climate model. The ModelE computational grid spacing is 2° latitude by 2.5° longitude and the RM3 grid spacing is 0.44°. ModelE precipitation climatology for June-September 1998-2002 is shown to be a good proxy for 30-year means so results based on the 5-year sample are presumed to be generally representative. Comparison with observational evidence shows several discrepancies in ModelE configuration of the boreal summer inter-tropical convergence zone (ITCZ). One glaring shortcoming is that ModelE simulations do not advance the West African rain band northward during the summer to represent monsoon precipitation onset over the Sahel. Results for 1998-2002 show that onset simulation is an important added value produced by downscaling with RM3. ModelE Eastern South Atlantic Ocean computed sea-surface temperatures (SST) are some 4 K warmer than reanalysis, contributing to large positive biases in overlying surface air temperatures (Tsfc). ModelE Tsfc are also too warm over most of Africa. RM3 downscaling somewhat mitigates the magnitude of Tsfc biases over the African continent, it eliminates the ModelE double ITCZ over the Atlantic and it produces more realistic orographic precipitation maxima. Parallel ModelE and RM3 simulations with observed SST forcing (in place of the predicted ocean) lower Tsfc errors but have mixed impacts on circulation and precipitation biases. Downscaling improvements of the meridional movement of the rain band over West Africa and the configuration of orographic precipitation maxima are realized irrespective of the SST biases.

  2. A new species of Dolicholana Bruce, 1986 (Isopoda, Cymothoidea, Cirolanidae), the first record of the genus from the Atlantic Ocean.

    PubMed

    Paiva, Ricardo J C; Souza-Filho, Jesser F

    2015-11-05

    The isopod genus Dolicholana Bruce, 1986, previously known only from the Indo-West Pacific, is recorded for the first time from the Atlantic Ocean. A new species, Dolicholana brucei sp. nov., is described from the northeastern Brazilian coast, and is the first record of the genus Dolicholana Bruce, 1986 for the Atlantic Ocean. The material was collected from the upper part of the continental slope off Rio Grande do Norte (150 m depth). The new species is characterized by pereopod 1 propodal palm being crenulate, ischium of pereopod 1 and 2 with a plumose seta on the anterior margin, peduncle of pleopods 3-5 bearing an accessory lobe acute on the distolateral angle, pleotelson posterior margin being rounded, and the uropodal endopod and the exopod apices distally being rounded. A revised key to the genus is provided.

  3. A Study of Mesoscale Gravity Waves over the North Atlantic with Satellite Observations and a Mesoscale Model

    NASA Technical Reports Server (NTRS)

    Wu, Dong L.; Zhang, Fuqing

    2004-01-01

    Satellite microwave data are used to study gravity wave properties and variabilities over the northeastern United States and the North Atlantic in the December-January periods. The gravity waves in this region, found in many winters, can reach the stratopause with growing amplitude. The Advanced Microwave Sounding Unit-A (AMSU-A) observations show that the wave occurrences are correlated well with the intensity and location of the tropospheric baroclinic jet front systems. To further investigate the cause(s) and properties of the North Atlantic gravity waves, we focus on a series of wave events during 19-21 January 2003 and compare AMSU-A observations to simulations from a mesoscale model (MM5). The simulated gravity waves compare qualitatively well with the satellite observations in terms of wave structures, timing, and overall morphology. Excitation mechanisms of these large-amplitude waves in the troposphere are complex and subject to further investigations.

  4. Experimental evaluation of atmospheric aerosol turbidity in different Atlantic regions

    SciTech Connect

    Plakhina, I.N.; Pyrogov, S.M.

    1994-12-31

    The statistical estimation of the experimental values of atmospheric turbidity are considered over the different Atlantic regions: from clean atmospheric conditions to very turbid conditions influenced by air masses from Africa containing continental Sahara aerosol. The factors influencing the variability of atmospheric turbidity are also analyzed. The contribution of aerosol to atmospheric attenuation of the direct solar radiation is estimated. It is shown that aerosol is the main factor determining the values of the optical thickness and its variability. The single scattering albedo is evaluated. The influence of the Sahara dust on the total solar radiation over the ocean surface is estimated. Based on the found relationship between aerosol optical thickness, total atmosphere, and aerosol turbidity in the surface layer, the height of the homogeneous atmosphere has been estimated. In addition, the aerosol generation by ocean surface in storm conditions has been considered.

  5. Geomagnetic observations on tristan da cunha, south atlantic ocean

    USGS Publications Warehouse

    Matzka, J.; Olsen, N.; Maule, C.F.; Pedersen, L.W.; Berarducci, A.M.; Macmillan, S.

    2009-01-01

    Few geomagnetic ground observations exist of the Earth's strongest core field anomaly, the South Atlantic Anomaly (SAA). The geomagnetic repeat station on the island Tristan da Cunha, located half-way between South Africa and South America at 37?? 05' S, 12?? 18' W, is therefore of crucial importance. We have conducted several sets of repeat station measurements during magnetically quiet conditions (Kp 2o or less) in 2004. The procedures are described and the results are compared to those from earlier campaigns and to the predictions of various global field models. Features of the local crustal bias field and the solar quiet daily variation are discussed. We also evaluate the benefit of continuous magnetic field recordings from Tristan da Cunha, and argue that such a data set is a very valuable addition to geomagnetic satellite data. Recently, funds were set up to establish and operate a magnetometer station on Tristan da Cunha during the Swarm magnetic satellite mission (2011-2014).

  6. Amphibian DNA shows marked genetic structure and tracks pleistocene climate change in northeastern Brazil.

    PubMed

    Carnaval, Ana Carolina; Bates, John M

    2007-12-01

    The glacial refugia paradigm has been broadly applied to patterns of species dynamics and population diversification. However, recent geological studies have demonstrated striking Pleistocene climate changes in currently semiarid northeastern Brazil at time intervals much more frequent than the climatic oscillations associated with glacial and interglacial periods. These geomorphic data documented recurrent pulses of wet regimes in the past 210,000 years that correlate with climate anomalies affecting multiple continents. While analyzing DNA sequences of two mitochondrial genes (cytochrome b and NADH-dehydrogenase subunit 2) and one nuclear marker (cellular-myelocytomatosis proto-oncogene) in the forest-associated frogs Proceratophrys boiei and Ischnocnema gr. ramagii, we found evidence of biological responses consistent with these pluvial maxima events. Sampled areas included old, naturally isolated forest enclaves within the semiarid Caatinga, as well as recent man-made fragments of humid coastal Atlantic forest. Results show that mtDNA lineages in enclave populations are monophyletic or nearly so, whereas nonenclave populations are polyphyletic and more diverse. The studied taxa show evidence of demographic expansions at times that match phases of pluvial maxima inferred from geological data. Divergence times between several populations fall within comparatively drier intervals suggested by geomorphology. Mitochondrial and nuclear data show local populations to be genetically structured, with some high levels of differentiation that suggest the need of further taxonomic work.

  7. Potential environmental contaminant risks to avian species at important bird areas in the northeastern United States

    USGS Publications Warehouse

    Rattner, B.A.; Ackerson, B.K.

    2008-01-01

    Environmental contaminants can have profound effects on birds, acting from the molecular through population levels of biological organization. An analysis of potential contaminant threats was undertaken at 52 Important Bird Areas (IBAs) within the northeastern Atlantic coast drainage. Using geographic information system methodology, data layers describing or integrating contamination (impaired waters, fish or wildlife consumption advisories, toxic release inventory sites, and estimates of pesticide use) were overlaid on buffered IBA boundaries, and the relative threat at each site was ranked. The most threatened sites include Jefferson National Forest (NF), Stewart B. McKinney National Wildlife Refuge (NWR), Great Dismal Swamp NWR, Blue Ridge Parkway, Shenandoah National Park (NP), Adirondack Park, Edwin B. Forsythe NWR, George Washington NF, Green Mountain NF, Long Island Piping Plover Beaches, and Merrymeeting Bay. These sites exhibited moderate to high percentages of impaired waters and had fish consumption advisories related to mercury and polychlorinated biphenyls, and were located in counties with substantial pesticide use. Endangered, threatened and Watch List bird species are present at these sites. The Contaminant Exposure and Effects--Terrestrial Vertebrates database was searched within buffered IBA boundaries, and for a moderate number of sites there was concordance between the perceived risk and contaminant exposure. Several of the IBAs with apparently substantial contaminant threats had no avian ecotoxicological data (e.g., George Washington NF, Shenandoah NP). Based upon this screening level risk assessment, contaminant biomonitoring is warranted at such sites, and data generated from these efforts should foster natural resource management activities.

  8. Regional movements of the tiger shark, Galeocerdo cuvier, off Northeastern Brazil: inferences regarding shark attack hazard.

    PubMed

    Hazin, Fábio H V; Afonso, André S; De Castilho, Pedro C; Ferreira, Luciana C; Rocha, Bruno C L M

    2013-09-01

    An abnormally high shark attack rate verified off Recife could be related to migratory behavior of tiger sharks. This situation started after the construction of the Suape port to the south of Recife. A previous study suggested that attacking sharks could be following northward currents and that they were being attracted shoreward by approaching vessels. In this scenario, such northward movement pattern could imply a higher probability of sharks accessing the littoral area of Recife after leaving Suape. Pop-up satellite archival tags were deployed on five tiger sharks caught off Recife to assess their movement patterns off northeastern Brazil. All tags transmitted from northward latitudes after 7-74 days of freedom. The shorter, soak distance between deployment and pop-up locations ranged between 33-209 km and implied minimum average speeds of 0.02-0.98 km.h-1. Both pop-up locations and depth data suggest that tiger shark movements were conducted mostly over the continental shelf. The smaller sharks moved to deeper waters within 24 hours after releasing, but they assumed a shallower (< 50 m) vertical distribution for most of the monitoring period. While presenting the first data on tiger shark movements in the South Atlantic, this study also adds new information for the reasoning of the high shark attack rate verified in this region.

  9. Variations in productivity and eolian fluxes in the northeastern Arabian Sea during the past 110 ka

    NASA Astrophysics Data System (ADS)

    Pourmand, Ali; Marcantonio, Franco; Schulz, Hartmut

    2004-04-01

    High-resolution (one to two samples/ka) radionuclide proxy records from core 93KL in the northeastern Arabian Sea provide evidence for millennial climate variability over the past 110 ka. We interpret 230Th-normalized 232Th fluxes as a proxy for eolian input, and authigenic uranium concentrations as a proxy for past productivity. We attribute orbital and suborbital variations in both proxies to changes in the intensity of the southwest Indian Ocean monsoon. The highest 230Th-normalized 232Th fluxes occur at times that are consistent with the timing of the Younger Dryas, Heinrich events 1-7 and cold Dansgaard-Oeschger stadial events recorded in the GISP2 ice core. Such high dust fluxes may be due to a weakened southwest monsoon in conjunction with strengthened northwesterlies from the Arabian Peninsula and Mesopotamia. Authigenic uranium concentrations, on the other hand, are highest during warm Dansgaard-Oeschger interstadials when the southwest monsoon is intensified relative to the northwesterly winds. Our results also indicate that on orbital timescales maximum average eolian fluxes coincide with the timing of marine isotopic stage (MIS) 2 and 4, while minimum fluxes occur during MIS 1, 3 and 5. Although the forcing mechanism(s) controlling suborbital variabilities in monsoonal intensity is still debated, our findings suggest an atmospheric teleconnection between the low-latitude southwest monsoon and North Atlantic climate.

  10. Long-term subsidence, cooling, and exhumation history along the South Atlantic passive continental margin in NW-Namibia

    NASA Astrophysics Data System (ADS)

    Menges, Daniel; Glasmacher, Ulrich Anton; Salomon, Eric; Hackspacher, Peter Christian; Schneider, Gabi

    2016-04-01

    has been estimated to ~ 2.7 km in the northeastern and ~ 4 km in the western Kaoko Belt. References 1. Miller, R.McG. Becker, T., 2008. The Geology of Namibia: Ministry of Mines and Energy, Geological Survey (Namibia). 2. Stollhofen, H., 1999. Karoo Synrift-Sedimentation und ihre tektonische Kontrolle am entstehenden Kontinentalrand Namibias: Z.dt.geol.Ges. 149: 519-632. 3. Renne, P.R., Glen, J.M., Milner, S.C., Duncan, A.R., 1996. Age of Etendeka flood volcanism and associated intrusions in southwestern Africa: Geology 24 (7): 659- 662. 4. Salomon, E., Koehn, D., Passchier, C., 2014. Brittle reactivation of ductile shear zones in NW Namibia in relation to South Atlantic rifting: Tectonics 34, 70-85.

  11. Rabies in southern Africa.

    PubMed

    Swanepoel, R; Barnard, B J; Meredith, C D; Bishop, G C; Brückner, G K; Foggin, C M; Hübschle, O J

    1993-12-01

    The first confirmed outbreak of rabies in Africa, believed to have followed the importation of an infected dog from England in 1892, occurred in the eastern Cape Province of South Africa, and was brought under control in 1894. An unconfirmed epidemic of rabies in dogs occurred in western Zambia in 1901. By the following year the disease had apparently spread along a major trade route, to cause an outbreak in Zimbabwe which engulfed most of the country before being eradicated in 1913. The existence of endemic rabies of viverrids (mongooses and genets) was confirmed in South Africa in 1928, and since then the viverrid disease has continued to occur widely on the interior plateau of the country with spill-over of infection to cattle and a variety of other animals. From about 1947 onwards, an invasive form of dog rabies spread from southern Zambia and/or Angola into Namibia, across northern and eastern Botswana into Zimbabwe and the northern Transvaal by 1950, entered Mozambique in 1952, and spread from there to Swaziland in 1954. Dog rabies extended from southern Mozambique into Natal in 1961 to cause a major epidemic which was brought under control in 1968. The disease re-entered northern Natal from Mozambique in 1976 and since then dog rabies has proved difficult to control in the peri-urban settlements of Natal-KwaZulu. The disease spread from Natal to Lesotho in 1982, and into the Transkei region of the eastern Cape Province in 1987, to reach the Ciskei by 1990. The spread of the disease in dogs was followed by the emergence of rabies of jackals and cattle in central Namibia, northern Botswana, Zimbabwe and the northern Transvaal. A unique outbreak of rabies in kudu antelope occurred in central Namibia from 1977 to 1985, apparently involving oral spread of infection between individuals. A few cases of rabies in the bat-eared fox were recognized each year in Namibia from 1967 onwards, and from the 1970s the occurrence of the disease in the fox has emerged as a

  12. Three climate cycles of millennial-scale vegetation change in Africa (Invited)

    NASA Astrophysics Data System (ADS)

    Dupont, L. M.

    2010-12-01

    Marine sediments can deliver long well-dated continuous sequences of environmental change, not only of the ocean but also of the continents. Vegetation records from these archives are often the only land-cover records to encompass several climate cycles. Comparing vegetation development during several cycles uncovers the structural and systematic differences between glacial and interglacial vegetation. Such data may help with the validation of the current earth system models including dynamic vegetation modules. A number of marine pollen records from the East Atlantic (ODP658, GIK16415, GIK16776, GIK16867, GeoB1016) and a new one from the Indian Ocean (MD96-2048) register the vegetation development in West and South Africa over a period of more than 300 thousand years covering at least three full glacial-interglacial cycles. From these dataset typical patterns of vegetation change in Africa are inferred and differences between cycles are discussed. Both latitudinal and altitudinal shifts in the vegetation have been recorded by pollen of e.g. Chenopods, Asteraceae (daisies), Ericaceae (heath), Podocarpus (yellow wood), Poaceae (grass), and lowland forest. While latitudinal shifts in the area of desert and savannah are typical in West Africa, altitudinal changes of the belt with mountainous forest and mountainous shrubs are more common in Southern Africa. During glacial times, vegetation includes ericaceous shrubs in Southern Africa, while desert shrubs expand in West Africa, and the area of the lowland forests is strongly reduced on the whole continent.

  13. Hierarchical model analysis of the Atlantic Flyway Breeding Waterfowl Survey

    USGS Publications Warehouse

    Sauer, John R.; Zimmerman, Guthrie; Klimstra, Jon D.; Link, William A.

    2014-01-01

    We used log-linear hierarchical models to analyze data from the Atlantic Flyway Breeding Waterfowl Survey. The survey has been conducted by state biologists each year since 1989 in the northeastern United States from Virginia north to New Hampshire and Vermont. Although yearly population estimates from the survey are used by the United States Fish and Wildlife Service for estimating regional waterfowl population status for mallards (Anas platyrhynchos), black ducks (Anas rubripes), wood ducks (Aix sponsa), and Canada geese (Branta canadensis), they are not routinely adjusted to control for time of day effects and other survey design issues. The hierarchical model analysis permits estimation of year effects and population change while accommodating the repeated sampling of plots and controlling for time of day effects in counting. We compared population estimates from the current stratified random sample analysis to population estimates from hierarchical models with alternative model structures that describe year to year changes as random year effects, a trend with random year effects, or year effects modeled as 1-year differences. Patterns of population change from the hierarchical model results generally were similar to the patterns described by stratified random sample estimates, but significant visibility differences occurred between twilight to midday counts in all species. Controlling for the effects of time of day resulted in larger population estimates for all species in the hierarchical model analysis relative to the stratified random sample analysis. The hierarchical models also provided a convenient means of estimating population trend as derived statistics from the analysis. We detected significant declines in mallard and American black ducks and significant increases in wood ducks and Canada geese, a trend that had not been significant for 3 of these 4 species in the prior analysis. We recommend using hierarchical models for analysis of the Atlantic

  14. Model Sensitivity to North Atlantic Freshwater Forcing at 8.2 Ka

    NASA Technical Reports Server (NTRS)

    Morrill, Carrie; Legrande, Allegra Nicole; Renssen, H.; Bakker, P.; Otto-Bliesner, B. L.

    2013-01-01

    We compared four simulations of the 8.2 ka event to assess climate model sensitivity and skill in responding to North Atlantic freshwater perturbations. All of the simulations used the same freshwater forcing, 2.5 Sv for one year, applied to either the Hudson Bay (northeastern Canada) or Labrador Sea (between Canada's Labrador coast and Greenland). This freshwater pulse induced a decadal-mean slowdown of 10-25%in the Atlantic Meridional Overturning Circulation (AMOC) of the models and caused a large-scale pattern of climate anomalies that matched proxy evidence for cooling in the Northern Hemisphere and a southward shift of the Intertropical Convergence Zone. The multi-model ensemble generated temperature anomalies that were just half as large as those from quantitative proxy reconstructions, however. Also, the duration of AMOC and climate anomalies in three of the simulations was only several decades, significantly shorter than the duration of approx.150 yr in the paleoclimate record. Possible reasons for these discrepancies include incorrect representation of the early Holocene climate and ocean state in the North Atlantic and uncertainties in the freshwater forcing estimates.

  15. Constraining South Atlantic growth with seafloor spreading data

    NASA Astrophysics Data System (ADS)

    Pérez-Díaz, Lucía.; Eagles, Graeme

    2014-09-01

    Recent models of South Atlantic opening history focus on early plate divergence by incorporating intracontinental deformation, which is poorly constrained. Aiming to avoid the uncertainties in this approach, we model the entire divergence history with a joint inversion for seafloor spreading data. For this history, the pre-Campanian motion parameters are the first to feature formal uncertainty estimates. We date the onset of spreading at 138 Ma, with movement along intracontinental accommodation zones leading to the assembly of South America by 123 Ma and Africa by 106 Ma. Part of the ridge in the Agulhas Basin jumped westward soon afterward toward the Bouvet plume, initiating the motion of a short-lived Malvinas Plate. The NE Georgia and Maud rises and Agulhas Plateau formed as a large igneous province over the plume. Farther north, part of the ridge jumped eastward toward the Tristan plume around 94-93 Ma but seems not to have resulted in independent plate motion. Our results show that the South Atlantic grew by diachronous breakup of continents on just two plates. Cretaceous intracontinental deformation in South America and Africa can be interpreted in terms of the accommodation of stress associated with northward propagation of this process. The pattern of accommodation is usually envisaged as focusing all of the strain in narrow belts. With our rotations, a commonly used set of such belts accounts instead for just 42-67% of the implied total strain. We suggest that the remainder was accommodated at all scales within the continental interiors and the extended continental margins.

  16. Ocean climate of the South East Atlantic observed from satellite data and wind models [review article

    NASA Astrophysics Data System (ADS)

    Hardman-Mountford, N. J.; Richardson, A. J.; Agenbag, J. J.; Hagen, E.; Nykjaer, L.; Shillington, F. A.; Villacastin, C.

    2003-10-01

    The near-coastal South East Atlantic Ocean off Africa is a unique and highly dynamic environment, comprising the cool Benguela Current, warm Angola Current and warm Agulhas Current. Strong coastal upwelling and the Congo River strongly influence primary production. Much of the present knowledge of the South East Atlantic has been derived from ship-borne measurements and in situ sensors, which cannot generally provide extensive spatial and temporal coverage. Similarly, previous satellite studies of the region have often focused on small spatial areas and limited time periods. This paper provides an improved understanding of seasonal and interannual variability in ocean dynamics along the South East Atlantic coast of Africa using time series of satellite and model derived data products. Eighteen years of satellite sea surface temperature data are complimented by 7 years of sea level data. Three years of chlorophyll a data illustrate the seasonal biological response, but the time series is not of sufficient length for investigating interannual variability in chlorophyll biomass. Modelled wind fields are used to describe atmospheric forcing of the surface ocean. This is the first synoptic-scale description of the South East Atlantic from a suite of large spatial coverage, long time series products. Previous studies of seasonal and interannual variability in the region are reviewed and used to interpret key oceanographic features and processes identified in the satellite data. Key findings of this study are: Descriptions of seasonal and interannual variability from these data show climate forcing of the South East Atlantic coast of Africa from both the northern and southern boundaries. Bimodal seasonal signals of equatorial origin propagate poleward along the Angolan coast, while the trade winds and events in the Agulhas region dominate the Agulhas Bank and Southern Benguela. The Northern Benguela is a mixed regime, under the influence of forcing from both directions

  17. Nitrogen Gas Fluxes in Northeastern Temperate Forests

    NASA Astrophysics Data System (ADS)

    Lafave, S.; Groffman, P. M.; Venterea, R. T.; Lovett, G. M.

    2002-12-01

    Nitrogen gas fluxes are a poorly quantified component of the nitrogen (N) cycle of forest ecosystems and are important to water quality, atmospheric chemistry and forest health. We measured fluxes of nitric oxide (NO), nitrous oxide (N2O) and dinitrogen (N2) in oak and maple stands in the Catskill mountains of New York State. Fluxes of NO and N2O were measured using in situ chambers and N2 flux was measured in intact cores incubated in a helium-oxygen atmosphere closed recirculation system in the laboratory. Fluxes of NO and N2O were higher in maple than in oak stands, which is consistent with previous work showing higher rates of N cycling under maple than oak. NO fluxes averaged 1.7 mg N m-2 d-1 in maple and 0.2 in oak. N2O fluxes averaged 0.10 mg N m-2 d-1 in maple and 0.004 in oak. However, N2 fluxes were higher in oak (2.3 mg N m-2 d-1) than maple (0.15), a surprising result that was supported by independent measurements of denitrification potential. There was marked variability in fluxes between replicate plots that was linked to the presence of understory vegetation and physical characteristics of the forest floor. Results suggest that N gas fluxes in northeastern temperate forests may be more important than previously thought and may be an important regulator of export of N to coastal waters, N-related atmospheric chemistry and forest N saturation.

  18. Denitrification in marine shales in northeastern Colorado

    USGS Publications Warehouse

    McMahon, P.B.; Böhlke, J.K.; Bruce, B.W.

    1999-01-01

    Parts of the South Platte River alluvial aquifer in northeastern Colorado are underlain by the Pierre Shale, a marine deposit of Late Cretaceous age that is <1000 m thick. Ground water in the aquifer is contaminated with NO3/-, and the shale contains abundant potential electron donors for denitrification in the forms of organic carbon and sulfide minerals. Nested piezometers were sampled, pore water was squeezed from cores of shale, and an injection test was conducted to determine if denitrification in the shale was a sink for alluvial NO3/- and to measure denitrification rates in the shale. Measured values of NO3/-, N2, NH4/+, ??15[NO3/-], ??15N[N2], and ??15N[NH4/+] in the alluvial and shale pore water indicated that denitrification in the shale was a sink for alluvial NO3/-. Chemical gradients, reaction rate constants, and hydraulic head data indicated that denitrification in the shale was limited by the slow rate of NO3/- transport (possibly by diffusion) into the shale. The apparent in situ first-order rate constant for denitrification in the shale based on diffusion calculations was of the order of 0.04-0.4 yr-1, whereas the potential rate constant in the shale based on injection tests was of the order of 60 yr-1. Chemical data and mass balance calculations indicate that organic carbon was the primary electron donor for denitrification in the shale during the injection test, and ferrous iron was a minor electron donor in the process. Flux calculations for the conditions encountered at the site indicate that denitrification in the shale could remove only a small fraction of the annual agricultural NO3/- input to the alluvial aquifer. However, the relatively large potential first-order rate constant for denitrification in the shale indicated that the percentage of NO3/- uptake by the shale could be considerably larger in areas where NO3/- is transported more rapidly into the shale by advection.

  19. Long distance dispersal and connectivity in amphi-Atlantic corals at regional and basin scales.

    PubMed

    Nunes, Flavia L D; Norris, Richard D; Knowlton, Nancy

    2011-01-01

    Among Atlantic scleractinian corals, species diversity is highest in the Caribbean, but low diversity and high endemism are observed in various peripheral populations in central and eastern Atlantic islands and along the coasts of Brazil and West Africa. The degree of connectivity between these distantly separated populations is of interest because it provides insight into processes at both evolutionary and ecological time scales, such as speciation, recruitment dynamics and the persistence of coral populations. To assess connectivity in broadly distributed coral species of the Atlantic, DNA sequence data from two nuclear markers were obtained for six coral species spanning their distributional ranges. At basin-wide scales, significant differentiation was generally observed among populations in the Caribbean, Brazil and West Africa. Concordance of patterns in connectivity among co-distributed taxa indicates that extrinsic barriers, such as the Amazon freshwater plume or long stretches of open ocean, restrict dispersal of coral larvae from region to region. Within regions, dispersal ability appears to be influenced by aspects of reproduction and life history. Two broadcasting species, Siderastrea siderea and Montastraea cavernosa, were able to maintain gene flow among populations separated by as much as 1,200 km along the coast of Brazil. In contrast, brooding species, such as Favia gravida and Siderastrea radians, had more restricted gene flow along the Brazilian coast.

  20. The strong association between western Sahelian monsoon rainfall and intense atlantic hurricanes

    SciTech Connect

    Landsea, C.W.; Gray, W.M. )

    1992-05-01

    Seasonal variability of Atlantic basin tropical cyclones is examined with respect to the monsoon rainfall over West Africa. Variations of intense hurricanes are of the most interest, as they are responsible for over three-quarters of United States tropical cyclone spawned destruction, though they account for only one-fifth of all landfalling cyclones. Intense hurricanes have also shown a strong downward trend during the last few decades. It is these storms that show the largest concurrent association with Africa's western Sahelian June-September rainfall for the years 1949-90. Though the Sahel is currently experiencing a multidecadal drought, the relationship between Atlantic tropical cyclones and western Sahelian rainfall is not dependent on the similar downward trends in both datasets. A detrended analysis confirms that a strong association still exists, though reduced somewhat in variance explained. Additionally, independent data from the years 1899 to 1948 substantiate the existence of the tropical cyclone-western Sahelian rainfall association. The fact that the Sahel periodically experiences multidecadal wet and dry regimes suggests that the current Sahelian drought, which began in the late 1960s, could be a temporary condition that may end in the near future. When this occurs, the Atlantic hurricane basin-especially the Caribbean islands and the United States East Coast-will likely see a large increase in intense hurricane activity associated with abundant Sahelian rainfall similar to the period of the late 1940s through the 1960s.

  1. Tracking leatherback turtles from the world's largest rookery: assessing threats across the South Atlantic.

    PubMed

    Witt, Matthew J; Augowet Bonguno, Eric; Broderick, Annette C; Coyne, Michael S; Formia, Angela; Gibudi, Alain; Mounguengui Mounguengui, Gil Avery; Moussounda, Carine; NSafou, Monique; Nougessono, Solange; Parnell, Richard J; Sounguet, Guy-Philippe; Verhage, Sebastian; Godley, Brendan J

    2011-08-01

    Despite extensive work carried out on leatherback turtles (Dermochelys coriacea) in the North Atlantic and Indo-Pacific, very little is known of the at-sea distribution of this species in the South Atlantic, where the world's largest population nests in Gabon (central Africa). This paucity of data is of marked concern given the pace of industrialization in fisheries with demonstrable marine turtle bycatch in African/Latin American waters. We tracked the movements of 25 adult female leatherback turtles obtaining a range of fundamental and applied insights, including indications for methodological advancement. Individuals could be assigned to one of three dispersal strategies, moving to (i) habitats of the equatorial Atlantic, (ii) temperate habitats off South America or (iii) temperate habitats off southern Africa. While occupying regions with high surface chlorophyll concentrations, these strategies exposed turtles to some of the world's highest levels of longline fishing effort, in addition to areas with coastal gillnet fisheries. Satellite tracking highlighted that at least 11 nations should be involved in the conservation of this species in addition to those with distant fishing fleets. The majority of tracking days were, however, spent in the high seas, where effective implementation of conservation efforts is complex to achieve. PMID:21208949

  2. Long Distance Dispersal and Connectivity in Amphi-Atlantic Corals at Regional and Basin Scales

    PubMed Central

    Nunes, Flavia L. D.; Norris, Richard D.; Knowlton, Nancy

    2011-01-01

    Among Atlantic scleractinian corals, species diversity is highest in the Caribbean, but low diversity and high endemism are observed in various peripheral populations in central and eastern Atlantic islands and along the coasts of Brazil and West Africa. The degree of connectivity between these distantly separated populations is of interest because it provides insight into processes at both evolutionary and ecological time scales, such as speciation, recruitment dynamics and the persistence of coral populations. To assess connectivity in broadly distributed coral species of the Atlantic, DNA sequence data from two nuclear markers were obtained for six coral species spanning their distributional ranges. At basin-wide scales, significant differentiation was generally observed among populations in the Caribbean, Brazil and West Africa. Concordance of patterns in connectivity among co-distributed taxa indicates that extrinsic barriers, such as the Amazon freshwater plume or long stretches of open ocean, restrict dispersal of coral larvae from region to region. Within regions, dispersal ability appears to be influenced by aspects of reproduction and life history. Two broadcasting species, Siderastrea siderea and Montastraea cavernosa, were able to maintain gene flow among populations separated by as much as 1,200 km along the coast of Brazil. In contrast, brooding species, such as Favia gravida and Siderastrea radians, had more restricted gene flow along the Brazilian coast. PMID:21799816

  3. Intracontinental deformation in southern Africa during the Late Cretaceous

    NASA Astrophysics Data System (ADS)

    Brown, Roderick; Summerfield, Michael; Gleadow, Andrew; Gallagher, Kerry; Carter, Andrew; Beucher, Romain; Wildman, Mark

    2014-12-01

    Intracontinental deformation accommodated along major lithospheric scale shear zone systems and within associated extensional basins has been well documented within West, Central and East Africa during the Late Cretaceous. The nature of this deformation has been established by studies of the tectonic architecture of sedimentary basins preserved in this part of Africa. In southern Africa, where the post break-up history has been dominated by major erosion, little evidence for post-break-up tectonics has been preserved in the onshore geology. Here we present the results of 38 new apatite fission track analyses from the Damara region of northern Namibia and integrate these new data with our previous results that were focused on specific regions or sections only to comprehensively document the thermo-tectonic history of this region since continental break-up in the Early Cretaceous. The apatite fission track ages range from 449 ± 20 Ma to 59 ± 3 Ma, with mean confined track lengths between 14.61 ± 0.1 μm (SD 0.95 μm) to 10.83 ± 0.33 μm (SD 2.84 μm). The youngest ages (c. 80-60 Ma) yield the longest mean track lengths, and combined with their spatial distribution, indicate major cooling during the latest Cretaceous. A simple numerical thermal model is used to demonstrate that this cooling is consistent with the combined effects of heating caused by magmatic underplating, related to the Paraná-Etendeka continental flood volcanism associated with rifting and the opening of the South Atlantic, and enhanced erosion caused by major reactivation of major lithospheric structures within southern Africa during a key period of plate kinematic change that occurred in the South Atlantic and SW Indian ocean basins between 87 and 56 Ma. This phase of intraplate tectonism in northern Namibia, focused in discrete structurally defined zones, is coeval with similar phases elsewhere in Africa and suggests some form of trans-continental linkage between these lithospheric zones.

  4. Oxygen and hydrogen isotope signatures of Northeast Atlantic water masses

    NASA Astrophysics Data System (ADS)

    Voelker, Antje H. L.; Colman, Albert; Olack, Gerard; Waniek, Joanna J.; Hodell, David

    2015-06-01

    Only a few studies have examined the variation of oxygen and hydrogen isotopes of seawater in NE Atlantic water masses, and data are especially sparse for intermediate and deep-water masses. The current study greatly expands this record with 527 δ18O values from 47 stations located throughout the mid- to low-latitude NE Atlantic. In addition, δD was analyzed in the 192 samples collected along the GEOTRACES North Atlantic Transect GA03 (GA03_e=KN199-4) and the 115 Iberia-Forams cruise samples from the western and southern Iberian margin. An intercomparison study between the two stable isotope measurement techniques (cavity ring-down laser spectroscopy and magnetic-sector isotope ratio mass spectrometry) used to analyze GA03_e samples reveals relatively good agreement for both hydrogen and oxygen isotope ratios. The surface (0-100 m) and central (100-500 m) water isotope data show the typical, evaporation related trend of increasing values equatorward with the exception for the zonal transect off Cape Blanc, NW Africa. Off Cape Blanc, surface water isotope signatures are modified by the upwelling of fresher Antarctic Intermediate Water (AAIW) that generally has isotopic values of 0.0 to 0.5‰ for δ18O and 0 to 2‰ for δD. Along the Iberian margin the Mediterranean Outflow Water (MOW) is clearly distinguished by its high δ18O (0.5-1.1‰) and δD (3-6‰) values that can be traced into the open Atlantic. Isotopic values in the NE Atlantic Deep Water (NEADW) are relatively low (δ18O: -0.1 to 0.5‰; δD: -1 to 4‰) and show a broader range than observed previously in the northern and southern convection areas. The NEADW is best observed at GA03_e Stations 5 and 7 in the central NE Atlantic basin. Antarctic Bottom Water isotope values are relatively high indicating modification of the original Antarctic source water along the flow path. The reconstructed δ18O-salinity relationship for the complete data set has a slope of 0.51, i.e., slightly steeper than the 0

  5. Large-scale circulation patterns associated with high concentrations of tropospheric ozone in the tropical South Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Fakhruzzaman, K. M.; Fishman, J.; Brackett, V. G.; Kendall, J. D.; Justice, C. O.

    1994-01-01

    Several years of satellite observations indicate the presence of enhanced amounts of tropospheric ozone over the tropical South Atlantic during the austral springs. Wide-spread biomass burning is prevalent over Africa and South America during the same time of the year. Another recent satellite technique has identified the locations of fires over the continents. In this study, we present an analysis of the prevailing meteorological conditions when the highest amounts of tropospheric ozone are present.

  6. Differential opening of the Central and South Atlantic Oceans and the opening of the West African rift system

    NASA Astrophysics Data System (ADS)

    Fairhead, J. D.; Binks, R. M.

    1991-02-01

    Plate tectonic studies of the development of the Central and South Atlantic Oceans using Seasat and Geosat altimeter and magnetic anomaly isochron data now provide quantitative models of seafloor spreading through time. Such models enable an initial assessment of the differential opening between these two oceanic basins to be determined. The Equatorial Atlantic is an integral part of this oceanic rifting process, allowing stresses arising from the differential opening to be dissipated into both the Caribbean and Africa along its northern and southern boundaries respectively. The tectonic model for the West African rift system, based on geological and geophysical studies, shows a series of strike-slip fault zones diverging into Africa from the Gulf of Guinea and dissipating their shear movement into the development of extensional basins orientated perpendicular to these faults zones. The development of the West African rift system was contemporaneous with the early opening of the South Atlantic, continued to develop well after the final breakup of South America from Africa and did not cease until the late Cretaceous when there was a major phase of basin inversion and deformation. Santonian ( ~ 80 Ma) deformation across the Benue Trough (Nigeria) is broadly contemporaneous with dextral shear reactivation of the central African fracture system which, in turn resulted in renewed extension in the Sudan basins during the late Cretaceous and early Tertiary. This paper illustrates the close linkage in both time and space between the history of the African rift basins and the opening of the Atlantic. Both exhibit distinct phases of evolution with the rift basins developing in direct response to the differential opening between the Central and South Atlantic in order to dissipate stresses generated by this opening. The Mesozoic tectonic model proposed is therefore one of an intimate interaction between oceanic and continental tectonics.

  7. Imaging the lithosphere of rifted passive margins using waveform tomography: North Atlantic, South Atlantic and beyond

    NASA Astrophysics Data System (ADS)

    Lebedev, Sergei; Schaeffer, Andrew; Celli, Nicolas Luca

    2016-04-01

    Lateral variations in seismic velocities in the upper mantle reflect variations in the temperature of the rocks at depth. Seismic tomography thus provides a proxy for lateral changes in the temperature and thickness of the lithosphere. It can map the deep boundaries between tectonic blocks with different properties and age of the lithosphere. Our 3D tomographic models of the upper mantle and the crust at the Atlantic and global scales are constrained by an unprecedentedly large global dataset of broadband waveform fits (over one million seismograms) and provide improved resolution of the lithosphere, compared to other available models. The most prominent high-velocity anomalies, seen down to 150-200 km depths, indicate the cold, thick, stable mantle lithosphere beneath Precambrian cratons, including those in North America, Greenland, northern and eastern Europe, Africa and South America. The dominant, large-scale, low-velocity feature is the global system of mid-ocean ridges, with broader low-velocity regions near hotspots, including Iceland. Currently active continental rifts show highly variable expression in the upper mantle, from pronounced low velocities to weak anomalies; this correlates with the amount of magmatism within the rift zone. Rifted passive margins have typically undergone cooling since the rifting and show more subtle variations in their seismic-velocity structure. Their thermal structure and evolution, however, are also shaped by 3D geodynamic processes since their formation, including cooling by the adjacent cratonic blocks inland and heating by warm oceanic asthenosphere.

  8. Long-term trends in aerosol and precipitation composition over the western North Atlantic Ocean at Bermuda

    NASA Astrophysics Data System (ADS)

    Keene, W. C.; Moody, J. L.; Galloway, J. N.; Prospero, J. M.; Cooper, O. R.; Eckhardt, S.; Maben, J. R.

    2014-03-01

    Since the 1980s, emissions of SO2 and NOx (NO + NO2) from anthropogenic sources in the United States (US) and Europe have decreased significantly suggesting that the export of oxidized S and N compounds from surrounding continents to the atmosphere overlying North Atlantic Ocean (NAO) has also decreased. The chemical compositions of aerosols and precipitation sampled daily on Bermuda (32.27° N, 64.87° W) from 1989 to 1997 and from 2006 to 2009 were evaluated to quantify the magnitudes, significance, and implications of associated tends in atmospheric composition. The chemical data were stratified based on FLEXPART retroplumes into four discrete transport regimes: westerly flow from the eastern North America (NEUS/SEUS); easterly trade-wind flow from northern Africa and the subtropical NAO (Africa); long, open-ocean, anticyclonic flow around the Bermuda High (Oceanic); and transitional flow from the relatively clean open ocean to the polluted northeastern US (North). Based on all data, annual average concentrations of non-sea-salt (nss) SO42- associated with aerosols and annual VWA concentrations in precipitation decreased significantly (by 22 and 49%, respectively) whereas annual VWA concentrations of NH4+ in precipitation increased significantly (by 70%). Corresponding trends in aerosol and precipitation NO3- and of aerosol NH4+ were insignificant. Nss SO42- in precipitation under NEUS/SEUS and Oceanic flow decreased significantly (61% each) whereas corresponding trends in particulate nss SO42- under both flow regimes were insignificant. Trends for precipitation were driven in part by decreasing emissions of SO2 over upwind continents and associated decreases in anthropogenic contributions to nss SO42- concentrations. Under NEUS/SEUS and Oceanic flow, the ratio of anthropogenic to biogenic contributions to to nss SO42- in the column scavenged by precipitation were relatively greater than those in near surface aerosol, which implies that, for these flow regimes

  9. Witches in the Atlantic World.

    ERIC Educational Resources Information Center

    Breslaw, Elaine

    2003-01-01

    Presents a lesson plan that focuses on witchcraft in the Atlantic world. Describes each of the four sections of the lesson that encompasses learning about terms and religious views on witchcraft to the history of witchcraft in New England, in the United States, and the Salem (Massachusetts) witchcraft trials. (CMK)

  10. New Sediment Data to Constrain Southern Atlantic Holocene Secular Variation

    NASA Astrophysics Data System (ADS)

    Korte, M. C.; Frank, U.; Nowaczyk, N. R.; Frederichs, T.; Brown, M. C.

    2014-12-01

    The present day geomagnetic field shows a notable weak zone stretching from South America to southern Africa. This is known as the South Atlantic Anomaly caused by a growing patch of reversed magnetic flux at the core-mantle boundary. The investigation of existence and evolution of similar features over the past millennia using global spherical harmonic models is hampered by the fact that at present only very few paleomagnetic data from equatorial and many southern hemisphere regions are available to constrain models well in these regions. Here, we present the results of paleomagnetic investigations of sediment cores from four locations at low latitudes. OPD 1078 and 1079 lie off the coast of Angola, GeoB6517-2 and ODP 1076D are located in the Congo Fan and M35003-4 is situated southeast of Grenada in the Tobago Basin. In addition to the paleomagnetic work all cores were subjected to a comprehensive set of rock magnetic measurements. Detailed age models based on radiocarbon dating are available for all locations, since the sites were already subjects of different aspects of climatic studies. We include these new records and previously presented data from two Ethiopian locations in millennial scale global models of the CALSxk type. Agreement of the new data to previous models and modifications of models due to the additional data are discussed, focussing in particular on magnetic field structures resembling the present-day South Atlantic Anomaly.

  11. Future Radiation Damage in Space due to South Atlantic Anomaly

    NASA Technical Reports Server (NTRS)

    Heirtzler, J. R.

    1999-01-01

    Predictions of radiation damage for Low Earth Orbit (LEO) satellites now use semi-empirical models developed from prior satellite data. From these models it is clear that the low field strength of the South Atlantic Anomaly (SAA) controls where the maximum radiation damage occurs. One may make an estimate of future radiation damage to LEO spacecraft if one can predict the future of the SAA. Although reliable maps of the geomagnetic field strength and its secular change have only been made in the last few decades, certain geomagnetic observatories in South America and Africa have recorded the geomagnetic field for a much longer time. These observatories show that the present geomagnetic field change has persisted for more than 100 years. In spite of the fact that a few observatories have shown sudden changes in secular variation, those around the SAA have shown a stable secular variation. Assuming that this will continue for the next 50 to 100 years one can show that the SAA will expand to cover most of the South Atlantic Ocean and will become much weaker. This will greatly intensify the radiation hazard in LEO, put significant new limitations on radiation-hardened hardware, severely restrict the length of time that humans can remain in orbit, and materially change the configuration of the radiation belts.

  12. North Atlantic salinity as a predictor of Sahel rainfall

    PubMed Central

    Li, Laifang; Schmitt, Raymond W.; Ummenhofer, Caroline C.; Karnauskas, Kristopher B.

    2016-01-01

    Water evaporating from the ocean sustains precipitation on land. This ocean-to-land moisture transport leaves an imprint on sea surface salinity (SSS). Thus, the question arises of whether variations in SSS can provide insight into terrestrial precipitation. This study provides evidence that springtime SSS in the subtropical North Atlantic ocean can be used as a predictor of terrestrial precipitation during the subsequent summer monsoon in Africa. Specifically, increased springtime SSS in the central to eastern subtropical North Atlantic tends to be followed by above-normal monsoon-season precipitation in the African Sahel. In the spring, high SSS is associated with enhanced moisture flux divergence from the subtropical oceans, which converges over the African Sahel and helps to elevate local soil moisture content. From spring to the summer monsoon season, the initial water cycling signal is preserved, amplified, and manifested in excessive precipitation. According to our analysis of currently available soil moisture data sets, this 3-month delay is attributable to a positive coupling between soil moisture, moisture flux convergence, and precipitation in the Sahel. Because of the physical connection between salinity, ocean-to-land moisture transport, and local soil moisture feedback, seasonal forecasts of Sahel precipitation can be improved by incorporating SSS into prediction models. Thus, expanded monitoring of ocean salinity should contribute to more skillful predictions of precipitation in vulnerable subtropical regions, such as the Sahel. PMID:27386525

  13. North Atlantic salinity as a predictor of Sahel rainfall.

    PubMed

    Li, Laifang; Schmitt, Raymond W; Ummenhofer, Caroline C; Karnauskas, Kristopher B

    2016-05-01

    Water evaporating from the ocean sustains precipitation on land. This ocean-to-land moisture transport leaves an imprint on sea surface salinity (SSS). Thus, the question arises of whether variations in SSS can provide insight into terrestrial precipitation. This study provides evidence that springtime SSS in the subtropical North Atlantic ocean can be used as a predictor of terrestrial precipitation during the subsequent summer monsoon in Africa. Specifically, increased springtime SSS in the central to eastern subtropical North Atlantic tends to be followed by above-normal monsoon-season precipitation in the African Sahel. In the spring, high SSS is associated with enhanced moisture flux divergence from the subtropical oceans, which converges over the African Sahel and helps to elevate local soil moisture content. From spring to the summer monsoon season, the initial water cycling signal is preserved, amplified, and manifested in excessive precipitation. According to our analysis of currently available soil moisture data sets, this 3-month delay is attributable to a positive coupling between soil moisture, moisture flux convergence, and precipitation in the Sahel. Because of the physical connection between salinity, ocean-to-land moisture transport, and local soil moisture feedback, seasonal forecasts of Sahel precipitation can be improved by incorporating SSS into prediction models. Thus, expanded monitoring of ocean salinity should contribute to more skillful predictions of precipitation in vulnerable subtropical regions, such as the Sahel. PMID:27386525

  14. Massive Open Online Courses for Africa by Africa

    ERIC Educational Resources Information Center

    Oyo, Benedict; Kalema, Billy Mathias

    2014-01-01

    Africa is known for inadequate access to all sorts of human needs including health, education, food, shelter, transport, security, and energy. Before the emergence of massive open online courses (MOOCs), open access to higher education (HE) was exclusive of Africa. However, as a generally affordable method of post-secondary education delivery,…

  15. Modulation of Atlantic Aerosols by the Madden-Julian Oscillation

    NASA Technical Reports Server (NTRS)

    Tian, B.; Waliser, D. E.; Kahn, Ralph A.; Wong, S.

    2010-01-01

    Much like the better-known EI Nino-Southern Oscillation, the Madden-Julian Oscillation (MJO) is a global-scale atmospheric phenomenon. The MJO involves periodic, systematic changes in the distribution of clouds and precipitation over the western Pacific and Indian oceans, along with differences in wind intensity over even more extensive areas, including the north and subtropical Atlantic Ocean. The lead authors of this paper developed a sophisticated mathematical technique for mapping the spatial and temporal behavior of changes in the atmosphere produced by the MJO. In a previous paper, we applied this technique to search for modulation of airborne particle amount in the eastern hemisphere associated with the "wet" (cloudy) vs. "dry" phases of the MJO. The study used primarily AVHRR, MODIS, and TOMS satellite-retrieved aerosol amount, but concluded that other factors, such as cloud contamination of the satellite signals, probably dominated the observed variations. The current paper looks at MJO modulation of desert dust transport eastward across the Atlantic from northern Africa, a region much less subject to systematic cloud contamination than the eastern hemisphere areas studied previously. In this case, a distinct aerosol signal appears, showing that dust is transported westward much more effectively during the MJO phase that favors westward-flowing wind, and such transport is suppressed when the MJO reduces these winds. Aside form the significant achievement in identifying such an effect, the result implies that an important component of global dust transport can be predicted based on the phase of the MJO. As a consequence, the impact of airborne dust on storm development in the Atlantic, and on dust deposition downwind of the desert sources, can also be predicted and more accurately modeled.

  16. AIDS in South Africa.

    PubMed

    Ijsselmuiden, C; Evian, C; Matjilla, J; Steinberg, M; Schneider, H

    1993-01-01

    The National AIDS Convention in South Africa (NACOSA) in October 1992 was the first real attempt to address HIV/AIDS. In Soweto, government, the African National Congress, nongovernmental organizations, and organized industry and labor representatives worked for 2 days to develop a national plan of action, but it did not result in a united effort to fight AIDS. The highest HIV infection rates in South Africa are among the KwaZulu in Natal, yet the Inkatha Freedom Party did not attend NACOSA. This episode exemplifies the key obstacles for South Africa to prevent and control AIDS. Inequality of access to health care may explain why health workers did not diagnose the first AIDS case in blacks until 1985. Migrant labor, Bantu education, and uprooted communities affect the epidemiology of HIV infection. Further, political and social polarization between blacks and whites contributes to a mindset that AIDS is limited to the other race which only diminishes the personal and collective sense of susceptibility and the volition and aptitude to act. The Department of National Health and Population Development's voluntary register of anonymously reported cases of AIDS specifies 1517 cumulative AIDS cases (October 1992), but this number is low. Seroprevalence studies show between 400,000-450,000 HIV positive cases. Public hospitals cannot give AIDS patients AZT and DDI. Few communities provided community-based care. Not all hospitals honor confidentiality and patients' need for autonomy. Even though HIV testing is not mandatory, it is required sometimes, e.g., HIV testing of immigrants. AIDS Training, Information and Counselling Centers are in urban areas, but not in poor areas where the need is most acute. The government just recently developed in AIDS education package for schools, but too many people consider it improper, so it is not being used. The poor quality education provided blacks would make it useless anyhow. Lifting of the academic boycott will allow South African

  17. Regions. [Africa, Middle East].

    PubMed

    1985-03-01

    This discussion of population focuses on the regions of Africa and the Middle East. In South Africa more white women are working but fewer black women work. The overall result is that the percentage of women who work is declining. Marita de Beer, research liaison executive at the South African Advertising Research Foundation, reports that the female population grew by 31% in the past 10 years while the number of working women has grown by only 11%. Among blacks the female population rose by 36%, but the number of workers among them declined by about 1%. Married women are among the fastest growing groups of working women in South Africa. The most recent estimate of the population of Nigeria is 92 million. According to Professor Vremudia Diejomaoh, Nigeria's population will probably reach 155 million by 2000 with 33% living in urban areas. In Saudi Arabia the Pan Arab Research Center recently completed a census of retail outlets in 3 metropolitan areas: Jeddah, Riyadh, and Dammam. The types of outlets surveyed include large supermarkets, small supermarkets, groceries with and without deep freeze, tobacco shops, meat shop/delis, small cafeterias, large restaurants/hotels, cosmetics shops or perfumeries, camera stores, toy shops, pharmacies, watch and gift shop, newsstands, department store, and appliance outlets. Using the Census of Retail Outlets as a base, Pan Arab Research Center also has a new distribution audit system that will cover 500 outlets. By plotting Arab countries according to their population policies and their current growth rates, it is possible to project where the middle class will grow fastest in the Arab world. The countries that have declining growth rates and strong population programs designed to encourage lower fertility rates among women are Egypt, Tunisia, Morocco, Algeria, and Lebanon. The countries most likely to have a better per capita distribution of resources within this decade are those where governments encourage reductions in

  18. Regions. [Africa, Middle East].

    PubMed

    1985-03-01

    This discussion of population focuses on the regions of Africa and the Middle East. In South Africa more white women are working but fewer black women work. The overall result is that the percentage of women who work is declining. Marita de Beer, research liaison executive at the South African Advertising Research Foundation, reports that the female population grew by 31% in the past 10 years while the number of working women has grown by only 11%. Among blacks the female population rose by 36%, but the number of workers among them declined by about 1%. Married women are among the fastest growing groups of working women in South Africa. The most recent estimate of the population of Nigeria is 92 million. According to Professor Vremudia Diejomaoh, Nigeria's population will probably reach 155 million by 2000 with 33% living in urban areas. In Saudi Arabia the Pan Arab Research Center recently completed a census of retail outlets in 3 metropolitan areas: Jeddah, Riyadh, and Dammam. The types of outlets surveyed include large supermarkets, small supermarkets, groceries with and without deep freeze, tobacco shops, meat shop/delis, small cafeterias, large restaurants/hotels, cosmetics shops or perfumeries, camera stores, toy shops, pharmacies, watch and gift shop, newsstands, department store, and appliance outlets. Using the Census of Retail Outlets as a base, Pan Arab Research Center also has a new distribution audit system that will cover 500 outlets. By plotting Arab countries according to their population policies and their current growth rates, it is possible to project where the middle class will grow fastest in the Arab world. The countries that have declining growth rates and strong population programs designed to encourage lower fertility rates among women are Egypt, Tunisia, Morocco, Algeria, and Lebanon. The countries most likely to have a better per capita distribution of resources within this decade are those where governments encourage reductions in

  19. 40 CFR 81.79 - Northeastern Oklahoma Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Northeastern Oklahoma Intrastate Air... Air Quality Control Regions § 81.79 Northeastern Oklahoma Intrastate Air Quality Control Region. The Metropolitan Tulsa Intrastate Air Quality Control Region has been renamed the Northeastern Oklahoma...

  20. 40 CFR 81.79 - Northeastern Oklahoma Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Northeastern Oklahoma Intrastate Air... Air Quality Control Regions § 81.79 Northeastern Oklahoma Intrastate Air Quality Control Region. The Metropolitan Tulsa Intrastate Air Quality Control Region has been renamed the Northeastern Oklahoma...