Sample records for reef health pathfinder

  1. PATHFINDER

    NSDL National Science Digital Library

    PATHFINDER is a new Web Site created by the Time Warner Group of companies. In Pathfinder you will find samples of Time Warner's products including: Time, People, Money, Entertainment Weekly, Fortune, and Real Simple.

  2. Shifting the paradigm of coral-reefhealth’ assessment

    Microsoft Academic Search

    Craig A. Downs; Cheryl M. Woodley; Robert H. Richmond; Lynda L. Lanning; Richard Owen

    2005-01-01

    Coral reefs are in crisis. Globally, our reefs are degrading at an accelerating rate and present methodologies for coral-reefhealth’ assessment, although providing important information in describing these global declines, have been unable to halt these declines. These assessments are usually employed with no clear purpose and using uncorrelated methods resulting in a failure to prevent or mitigate coral reef

  3. Quality Health Information on the Internet: Developing a Diabetes Pathfinder for the Chinese Population

    PubMed Central

    Cleveland, Ana D.; Philbrick, Jodi; Pan, Xuequn (Della); Yu, Xinyu; Chen, Jiangping; O'Neill, Marty; Smith, Lisa

    2010-01-01

    A Web-based bilingual diabetes information pathfinder was created to help the Chinese population access quality health information on the Internet as part of a collaborative outreach project in the Dallas-Fort Worth area. A survey was conducted to identify the demographics, Internet usage, health information needs, and preferences for training sessions of the Chinese population. Breast cancer, diabetes, and breast cancer were the top three diseases of interest. The process of developing the pathfinder is described from start to finish, and it can serve as a model for the development of others. Pathfinder training sessions were held. PMID:20526379

  4. Oral health related behaviors among adult Tanzanians: a national pathfinder survey

    Microsoft Academic Search

    Joyce R Masalu; Emil N Kikwilu; Febronia K Kahabuka; Ahadieli R Senkoro; Irene A Kida

    2009-01-01

    BACKGROUND: The oral health education programs which have been organised and delivered in Tanzania were not based on a thorough understanding of behaviours which influence oral health. Therefore, evaluation of these programs became difficult. This study aimed at investigating the oral health related behaviours and their determinants among Tanzanian adults. METHODS: A national pathfinder cross sectional survey was conducted in

  5. Pathfinder-Plus on flight in Hawaii

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Pathfinder-Plus on a flight over Hawaii in 1998. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

  6. Pathfinder-Plus on flight over Hawaii

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Pathfinder-Plus flying over the Hawaiian Islands in 1998 with Ni'ihau Island in the background. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

  7. Pathfinder-Plus on flight over Hawaii

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Pathfinder-Plus on flight over Hawaii. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

  8. Research Spotlight: New method to assess coral reef health

    NASA Astrophysics Data System (ADS)

    Tretkoff, Ernie

    2011-03-01

    Coral reefs around the world are becoming stressed due to rising temperatures, ocean acidification, overfishing, and other factors. Measuring community level rates of photosynthesis, respiration, and biogenic calcification is essential to assessing the health of coral reef ecosystems because the balance between these processes determines the potential for reef growth and the export of carbon. Measurements of biological productivity have typically been made by tracing changes in dissolved oxygen in seawater as it passes over a reef. However, this is a labor-intensive and difficult method, requiring repeated measurements. (Geophysical Research Letters, doi:10.1029/2010GL046179, 2011)

  9. Pathfinder-Plus takes off on flight in Hawaii

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Pathfinder-Plus on a flight over Hawaii in 1998. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

  10. Pathfinder-Plus on a flight in Hawaii

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Pathfinder-Plus on a flight in 1998 over Hawaiian waters. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

  11. Pathfinder-Plus on flight over Hawaiian Islands

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Pathfinder-Plus on flight over Hawaiian Islands in 1998. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

  12. Pathfinder-Plus on flight over Hawaiian island N'ihau

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Pathfinder-Plus on a flight over the Hawaiian island of N'ihau in 1998. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

  13. Pathfinder-Plus on a flight over Hawaiian island N'ihau

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Pathfinder-Plus on a flight over the Hawaiian island of N'ihau in 1998. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

  14. Pathfinder-Plus on flight near Hawaiian island N'ihau

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Pathfinder-Plus on a flight with the Hawaiian island of N'ihau in the background. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

  15. New mapping techniques help assess the health of Hawaii's coral reefs

    USGS Publications Warehouse

    Field, M.E.; Chavez, P.S., Jr.; Evans, K.R.; Cochran, S.A.

    2001-01-01

    The U.S. Geological Survey (USGS) is working closely with academic institutions and state and Federal agencies to assess the factors that affect the health of Hawaii's and our Nation's coral reefs. In order to establish a basis from which scientists can objectively detect changes in reef health, the USGS and its cooperators are applying many new techniques to the mapping and monitoring of coral reefs in Hawaii.

  16. Pathfinder-Plus on flight over Hawaiian Islands, with N'ihau and Lehua in the background

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Pathfinder-Plus on flight over Hawaiian Islands, with N'ihau and Lehua in the background. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

  17. Emotional Pathfinding

    Microsoft Academic Search

    Toby Donaldson; Andrew Park; I-ling Lin

    2004-01-01

    \\u000a This paper presents a study of the influence of emotions on the behaviour of an intelligent pathfinding agent. A model of\\u000a pathfinding is proposed that takes into account the emotional state of the agent. Results show that blindly following the\\u000a most urgent emotion can lead to degenerate behaviour, and that cross-exclusion can be used to effectively moderate emotional\\u000a influences. Applications

  18. [General health, reproductive health and internet. A pathfinder for French speaking adolescents].

    PubMed

    Alvin, P; Buceta, A; Dailland, F

    2003-02-01

    Internet offers interesting information concerning health issues. This paper presents a selection of french sites destined for youth about general and reproductive health. Pediatricians could recommend them to their adolescent patients. These addresses and their content need to be checked at regular intervals PMID:12829369

  19. Coastal nutrification and coral health at Porto Seguro reefs, Brazil

    NASA Astrophysics Data System (ADS)

    Costa, O.; Attrill, M.; Nimmo, M.

    2003-04-01

    Human activities have substantially increased the natural flux of nutrients to coastal systems worldwide. In Brazilian reefs, all major stresses (sedimentation, overfishing, tourism-related activities and nutrification) are human induced. To assess nutrification levels in Brazilian coastal reefs, measurements of the distribution patterns of nutrients and chlorophyll concentrations were conducted in three nearshore and offshore reefs with distinct nutrient inputs along the south coast of Bahia State. Seawater and porewater samples were analysed for soluble reactive phosphorus, total oxidised nitrogen and reactive silica. Benthic surveys were performed at all sites to investigate the relationships between benthic community composition and nutrient and chlorophyll concentrations. Sampling was undertaken in dry and rainy seasons. Results of both seawater and porewater nutrient measurements revealed the occurrence of consistent spatial and temporal patterns. An inshore-offshore gradient reflects the occurrence of land-based point sources, with significant amount of nutrients being delivered by human activities on the coast (untreated sewage and groundwater seepage). Another spatial gradient is related to distance from a localized source of pollution (an urban settlement without sewerage treatment) with two nearshore reefs presenting distinct nutrient and chlorophyll concentrations. Seasonal variations suggest that submarine groundwater discharge (SGD) is the primary source of nutrients for the coastal reefs during rainy season. The data also suggests that the SGD effect is not restricted to nearshore reefs, and may be an important factor controlling the differences between landward and seaward sides on the offshore reef. Benthic community assessment revealed that turf alga is the dominant group in all studied reefs and that zoanthids are the organisms most adapted to take advantage of nutrient increase in coastal areas. At nearshore reefs, there was a negative correlation between zoanthids and algal abundance and a positive correlation with the amount of available space for settlement. On the offshore reef, correlation of algal cover with both zoanthids and available space were negative, suggesting that hard substrate may be the primary limiting factor for algal settlement and growth in the nearshore reefs. Highly variable physical disturbances (like wave energy and low tide exposure) between landward and seaward reef sides appear to be the factors controlling algal distribution in the offshore reef. Highly spatial variability in coral cover ultimately reflects the patchy distribution of stony corals over the reefs.

  20. LISA Pathfinder

    NASA Technical Reports Server (NTRS)

    Stebbins, Robin

    2008-01-01

    USA Pathfinder is a space mission dedicated to demonstrating technology for the Laser Interferometer Space Antenna (LISA). LISA is a joint ESA/NASA mission to detect low-frequency gravitational waves on the 0.0001 to 0.1 Hz frequency band. LISA is expected to observe 100's of merging massive black hole binaries out z-15, tens of thousands of close compact binary systems in the Milky Way, merging intermediate-mass black hole binaries, tens of stellar-mass black holes falling into supermassive black holes in galactic centers, and possibly other exotic sources. Several critical LISA technologies have not been demonstrated at the requisite level of performance. In spaceflight, and some fight hardware cannot be tested in a 1-g environment. Hence, the LISA Pathfinder mission is being implemented to demonstrate these critical LISA technologies in a relevant flight environment. LISA Pathfinder mimics one arm of the LISA constellation by shrinking the 5-million-kilometer armlength down to a few tens of centimeters. The experimental concept is to measure the relative separation between two test masses nominally following their own geodesics, and thereby determine the relative residual acceleration between them near 1 mHz, about a decade above the lowest frequency required by LISA. To implement such a concept, disturbances on the test masses must be kept very small by many design features, but chiefly by "drag-free" flight. A drag-free spacecraft follows a free-falling test mass which it encloses, but has no mechanical connection to. The spacecraft senses it's orientation and separation with respect to the proof mass, and its propulsion system is commanded to keep the spacecraft centered about the test mass. Thus, the spacecraft shields the test mass from most external influences, and minimizes the effect of force gradients arising from the spacecraft, and acting on the test mass. LISA Pathfinder will compare the geodesic of one test mass against that of the other. Only a metrology system based on interferometry can achieve the displacement sensitivity. Interferometers monitor the separation of both test masses with a sensitivity comparable to that required by LISA, and using the same technologies. LISA Pathfinder is scheduled to be launched in the first half of 1020 to a Lissajous orbit around the first Sun-Earth Lagrange point, L1. In addition to a complete European technology package (the LISA Technology Package, or LTP), LISA Pathfinder will also carry thrusters and software, known as ST-7, a part of NASA's New Millennium Program.

  1. LISA Pathfinder

    Microsoft Academic Search

    P. McNamara; S. Vitale; K. Danzmann

    2008-01-01

    LISA Pathfinder (formerly known as SMART-2) is an ESA mission designed to pave the way for the joint ESA\\/NASA Laser Interferometer Space Antenna (LISA) mission by testing in-flight the critical technologies required for space-borne gravitational wave detection; it will put two test masses in a near-perfect gravitational free fall, and control and measure their motion with an unprecedented accuracy. This

  2. Mars Pathfinder

    NSDL National Science Digital Library

    NASA Jet Propulsion Laboratory

    This extensive site from NASA's Jet Propulsion Laboratory is divided into two parts. The first features information available at the time of Pathfinder's 1997 landing on Mars while the second part focuses on information available at the end of the mission. Each part presents archived news and science articles, data and general mission information as well as many images. The site is searchable and includes links to related information.

  3. Clues to Coral Reef Ecosystem Health: Spectral Analysis Coupled with Radiative Transfer Modeling

    NASA Astrophysics Data System (ADS)

    Guild, L.; Ganapol, B.; Kramer, P.; Armstrong, R.; Gleason, A.; Torres, J.; Johnson, L.; Garfield, N.

    2003-12-01

    Coral reefs are among the world's most productive and biologically rich ecosystems and are some of the oldest ecosystems on Earth. Coralline structures protect coastlines from storms, maintain high diversity of marine life, and provide nurseries for marine species. Coral reefs play a role in carbon cycling through high rates of organic carbon metabolism and calcification. Coral reefs provide fisheries habitat that are the sole protein source for humans on remote islands. Reefs respond immediately to environmental change and therefore are considered "canaries" of the oceans. However, the world's reefs are in peril: they have shrunk 10-50% from their historical extent due to climate change and anthropogenic activity. An important contribution to coral reef research is improved spectral distinction of reef species' health where anthropogenic activity and climate change impacts are high. Relatively little is known concerning the spectral properties of coral or how coral structures reflect and transmit light. New insights into optical processes of corals under stressed conditions can lead to improved interpretation of airborne and satellite data and forecasting of immediate or long-term impacts of events such as bleaching and disease in coral. We are investigating the spatial and spectral resolution required to detect remotely changes in reef health by coupling spectral analysis of in situ spectra and airborne spectral data with a new radiative transfer model called CorMOD2. Challenges include light attenuation by the water column, atmospheric scattering, and scattering caused by the coral themselves that confound the spectral signal. In CorMOD2, input coral reflectance measurements produce modeled absorption through an inversion at each visible wavelength. The first model development phase of CorMOD2 imposes a scattering baseline that is constant regardless of coral condition, and further specifies that coral is optically thick. Evolution of CorMOD2 is towards a coral-specific radiative transfer model that includes coral biochemical concentrations, specific absorptivities of coral components, and transmission measurements from coral surfaces.

  4. Mapping Health of Bonaire Coral Reefs Using a Lightweight Hyperspectral Mapping System - First Results

    NASA Astrophysics Data System (ADS)

    Suomalainen, Juha; Mucher, Sander; Kooistra, Lammert; Meesters, Erik

    2014-05-01

    The Dutch Caribbean island of Bonaire is one of the world's top diving holiday destinations much due to its clear waters and healthy coral reefs. The coral reefs surround the western side of the island as an approximately 50-150m wide band. However, the general consensus is that the extent and biodiversity of the Bonarian coral reef is constantly decreasing due to anthropogenic pressures. The last extensive study of the health of the reef ecosystem was performed in 1985 by Van Duyl creating an underwater atlas. In order to update this atlas of Bonaire's coral reefs, in October 2013, a hyperspectral mapping campaign was performed using the WUR Hyperspectral Mapping System (HYMSY). A dive validation campaign has been planned for early 2014. The HYMSY consists of a custom pushbroom spectrometer (range 450-950nm, FWHM 9nm, ~20 lines/s, 328 pixels/line), a consumer camera (collecting 16MPix raw image every 2 seconds), a GPS-Inertia Navigation System (GPS-INS), and synchronization and data storage units. The weight of the system at take-off is 2.0kg allowing it to be mounted on varying platforms. In Bonaire the system was flown on two platforms. (1) on a Cessna airplane to provide a coverage for whole west side of the island with a hyperspectral map in 2-4m resolution and a RGB orthomosaic in 15cm resolution, and (2) on a kite pulled by boat and car to provide a subset coverage in higher resolution. In this presentation we will present our mapping technique and first results including a preliminary underwater atlas and conclusions on reef development.

  5. Use of integrated landscape indicators to evaluate the health of linked watersheds and coral reef environments in the Hawaiian islands.

    PubMed

    Rodgers, Ku'ulei S; Kido, Michael H; Jokiel, Paul L; Edmonds, Tim; Brown, Eric K

    2012-07-01

    A linkage between the condition of watersheds and adjacent nearshore coral reef communities is an assumed paradigm in the concept of integrated coastal management. However, quantitative evidence for this "catchment to sea" or "ridge to reef" relationship on oceanic islands is lacking and would benefit from the use of appropriate marine and terrestrial landscape indicators to quantify and evaluate ecological status on a large spatial scale. To address this need, our study compared the Hawai'i Watershed Health Index (HI-WHI) and Reef Health Index (HI-RHI) derived independently of each other over the past decade. Comparisons were made across 170 coral reef stations at 52 reef sites adjacent to 42 watersheds throughout the main Hawaiian Islands. A significant positive relationship was shown between the health of watersheds and that of adjacent reef environments when all sites and depths were considered. This relationship was strongest for sites facing in a southerly direction, but diminished for north facing coasts exposed to persistent high surf. High surf conditions along the north shore increase local wave driven currents and flush watershed-derived materials away from nearshore waters. Consequently, reefs in these locales are less vulnerable to the deposition of land derived sediments, nutrients and pollutants transported from watersheds to ocean. Use of integrated landscape health indices can be applied to improve regional-scale conservation and resource management. PMID:22538320

  6. Status monitoring and health assessment of Luhuitou fringing reef of Sanya, Hainan, China

    Microsoft Academic Search

    Qiaomin Zhang; Qi Shi; Gang Chen; T. C. W. Fong; D. C. C. Wong; Hui Huang; Hankui Wang; Meixia Zhao

    2006-01-01

    The monitoring survey and health assessment for benthic community were carried out in Luhuitou fringing reef of Sanya, Hainan,\\u000a China in 2002. Monitoring survey included manta tow, line intercept transect, video transect and digital photograph. The mean\\u000a live coral cover was 23.40%. Comparison of used monitoring methods showed that video transect can replace line intercept transect,\\u000a and 50 m transect

  7. Coral Reefs Under Stress

    NSDL National Science Digital Library

    Peter Mumby (University of Exeter; )

    2009-10-05

    Coral reefs are more critical to an oceanâ??s health than you might think, and the effects of climate change and ocean acidification are effectively damaging and destroying most reefs in the world. Coral reefs provide many important ecosystem services, including: providing food, shelter, and meeting places for thousands of animals; anchoring sand for recreational beaches; and supplying building materials for remote peoples.

  8. Jurassic Reef Park

    NSDL National Science Digital Library

    Reinhold Leinfelder

    This is a bilingual, educational website from Munich, Germany. The main feature is a virtual field trip to the reefs of the Jurassic period. Besides a view of the Jurassic reefs, their builders, and their ecological settings, there is also an emphasis on the importance of modern reefs as indicators of the state-of-health of the globe and evidence of how some changes in the composition of reefs may represent the forerunners of catastrophic, regional or global, environmental change.

  9. NOAA's Coral Reef

    NSDL National Science Digital Library

    In an effort to centralize information on Coral Reefs, the National Oceanic and Atmospheric Administration (NOAA) has launched this site on Coral Reefs. The site serves both as a news resource (see the frequently updated News Releases section) as well as a basic information resource (see Year of the Reef 1997 and Coral Reef Photos) on coral reefs. For information on current research (scientific and citizen), see the Coral Health and Monitoring Program, the Great American Fish Count, or the Coral Reef Initiative sections. Additionally, a dozen Coral Reef Links point users to further resources. For the pure enthusiast or beginning college student, this site serves as a fine entry-way into learning about Coral Reefs.

  10. Pathfinder aircraft in flight

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The Pathfinder solar-powered research aircraft is silhouetted against a clear blue sky as it soars aloft during a checkout flight from the Dryden Flight Research Center, Edwards, California, November, 1996. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

  11. Pathfinder aircraft flight

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The Pathfinder research aircraft's wing structure is clearly defined as it soars under a clear blue sky during a test flight from Dryden Flight Research Center, Edwards, California, in November of 1996. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

  12. Pathfinder: Humans in space

    NASA Technical Reports Server (NTRS)

    Anderson, John L.

    1988-01-01

    Viewgraphs are presented on the Pathfinder program. Information is given on human exploration of the solar system, technical requirements interfaces, program objectives, space suits, human performance, man-machine systems, space habitats, life support systems, and artificial gravity

  13. Pathfinder aircraft in flight

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Pathfinder is shown flying low over Rogers Dry Lakebed at Edwards Air Force Base. Its wing is very flexible, while its upper surface is covered with solar cells. While at high altitude, the vehicle was controlled by a remote pilot on the ground, but when the concept is fully developed, a vehicle larger than but similar to Pathfinder may be able to stay aloft for months at a time, without landing and with only sunlight as its 'fuel.'

  14. Mars Pathfinder Mission

    NSDL National Science Digital Library

    1997-01-01

    The Mars Pathfinder Mission is a historic event and NASA's site offers a comprehensive account of its background, objectives, and progress. Users will find the latest news, a mission timeline, and information on the landing site and the instruments involved, including the Rover Sojourner. Additional features offered at this site include education and outreach activities for students, current data received from the spacecraft, and a realtime simulation of the Pathfinder entry, descent, and landing.

  15. Assessing community values for reducing agricultural emissions to improve water quality and protect coral health in the Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Rolfe, John; Windle, Jill

    2011-12-01

    Policymakers wanting to increase protection of the Great Barrier Reef from pollutants generated by agriculture need to identify when measures to improve water quality generate benefits to society that outweigh the costs involved. The research reported in this paper makes a contribution in several ways. First, it uses the improved science understanding about the links between management changes and reef health to bring together the analysis of costs and benefits of marginal changes, helping to demonstrate the appropriate way of addressing policy questions relating to reef protection. Second, it uses the scientific relationships to frame a choice experiment to value the benefits of improved reef health, with the results of mixed logit (random parameter) models linking improvements explicitly to changes in "water quality units." Third, the research demonstrates how protection values are consistent across a broader population, with some limited evidence of distance effects. Fourth, the information on marginal costs and benefits that are reported provide policymakers with information to help improve management decisions. The results indicate that while there is potential for water quality improvements to generate net benefits, high cost water quality improvements are generally uneconomic. A major policy implication is that cost thresholds for key pollutants should be set to avoid more expensive water quality proposals being selected.

  16. Martian Surface & Pathfinder Airbags

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image of the Martian surface was taken in the afternoon of Mars Pathfinder's first day on Mars. Taken by the Imager for Mars Pathfinder (IMP camera), the image shows a diversity of rocks strewn in the foreground. A hill is visible in the distance (the notch within the hill is an image artifact). Airbags are seen at the lower right.

    The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.' It stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  17. The LISA Pathfinder Mission

    NASA Astrophysics Data System (ADS)

    Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Brandt, N.; Bursi, A.; Caleno, M.; Cavalleri, A.; Cesarini, A.; Cruise, M.; Danzmann, K.; Diepholz, I.; Dolesi, R.; Dunbar, N.; Ferraioli, L.; Ferroni, V.; Fitzsimons, E.; Freschi, M.; Gallegos, J.; García Marirrodriga, C.; Gerndt, R.; Gesa, L. I.; Gibert, F.; Giardini, D.; Giusteri, R.; Grimani, C.; Harrison, I.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hueller, M.; Huesler, J.; Inchauspé, H.; Jennrich, O.; Jetzer, P.; Johlander, B.; Karnesis, N.; Kaune, B.; Korsakova, N.; Killow, C.; Lloro, I.; Maarschalkerweerd, R.; Madden, S.; Mance, D.; Martín, V.; Martin-Porqueras, F.; Mateos, I.; McNamara, P.; Mendes, J.; Mendes, L.; Moroni, A.; Nofrarias, M.; Paczkowski, S.; Perreur-Lloyd, M.; Petiteau, A.; Pivato, P.; Plagnol, E.; Prat, P.; Ragnit, U.; Ramos-Castro, J.; Reiche, J.; Romera Perez, J. A.; Robertson, D.; Rozemeijer, H.; Russano, G.; Sarra, P.; Schleicher, A.; Slutsky, J.; Sopuerta, C. F.; Sumner, T.; Texier, D.; Thorpe, J.; Trenkel, C.; Tu, H. B.; Vetrugno, D.; Vitale, S.; Wanner, G.; Ward, H.; Waschke, S.; Wass, P.; Wealthy, D.; Wen, S.; Weber, W.; Wittchen, A.; Zanoni, C.; Ziegler, T.; Zweifel, P.

    2015-05-01

    LISA Pathfinder (LPF), the second of the European Space Agency's Small Missions for Advanced Research in Technology (SMART), is a dedicated technology validation mission for future spaceborne gravitational wave detectors, such as the proposed eLISA mission. LISA Pathfinder, and its scientific payload - the LISA Technology Package - will test, in flight, the critical technologies required for low frequency gravitational wave detection: it will put two test masses in a near-perfect gravitational free-fall and control and measure their motion with unprecedented accuracy. This is achieved through technology comprising inertial sensors, high precision laser metrology, drag-free control and an ultra-precise micro-Newton propulsion system. LISA Pathfinder is due to be launched in mid-2015, with first results on the performance of the system being available 6 months thereafter. The paper introduces the LISA Pathfinder mission, followed by an explanation of the physical principles of measurement concept and associated hardware. We then provide a detailed discussion of the LISA Technology Package, including both the inertial sensor and interferometric readout. As we approach the launch of the LISA Pathfinder, the focus of the development is shifting towards the science operations and data analysis - this is described in the final section of the paper

  18. The LISA Pathfinder Mission

    NASA Astrophysics Data System (ADS)

    McNamara, Paul

    2015-04-01

    LISA Pathfinder is the second of the European Space Agency's Small Missions for Advanced Research and Technology (SMART). The goal of LISA Pathfinder (LPF) is to demonstrate the technologies required for future laser interferometric spaceborne gravitational wave detectors. The development of the LPF hardware is now over, and final integration and testing of the spacecraft and payload is underway. The delivery of the opto-mechanical heart of the payload is scheduled for Q2 2015, following which the final system tests will be performed. Launch is scheduled for September 2015. First results will be available approximately 3 months after launch. In this presentation I will describe the LISA Pathfinder mission, and provide the current status of the mission and remaining activities to launch and operations.

  19. Martian terrain near Pathfinder

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Large boulders are visible in this enlargement of pictures taken by the Mars Pathfinder lander camera on July 4, 1997. The landing site is in the dry flood channel named Ares Valles. The boulders probably represent deposits from one of the catastrophic floods that carved the ancient channel. Between the rocks is brownish windblown soil. The gray-tan sky results from dust particles in the atmosphere.

    Pathfinder, a low-cost Discovery mission, is the first of a new fleet of spacecraft that are planned to explore Mars over the next ten years. Mars Global Surveyor, already en route, arrives at Mars on September 11 to begin a two year orbital reconnaissance of the planet's composition, topography, and climate. Additional orbiters and landers will follow every 26 months.

    Mars Pathfinder was developed and managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  20. Pathfinder Spies Dust Devils

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This set of images from NASA's 1997 Pathfinder mission highlight the dust devils that gust across the surface of Mars. The right image shows the dusty martian sky as our eye would see it. The left image has been enhanced to expose the dust devils that lurk in the hazy sky.

  1. Coral Reefs

    NSDL National Science Digital Library

    dramsden

    2009-11-19

    This page offers information on coral reefs. Coral reefs are often refered to as the rainforest of the oceans. This exploration will help you to see why that is. Follow these links to learn about coral reefs. This link will take you to Florida where a girl will take guide you over a coral reef. Coral Kid This site ...

  2. Reef ED

    NSDL National Science Digital Library

    Great Barrier Reef Marine Park Authority's resource and activity center for teachers and students. Find teaching units for K-12 on: coral reef habitats and marine life; human dependence and impacts on the reef; biodiversity and threatened species; coastal zone and reef management. Lesson plans offer objectives, inquiry learning focus activities, resources, class or field activities. Student pages contain: marine life profiles; reef conservation projects; role playing activities; web investigations. Excellent image library (stills and video).

  3. The LISA Pathfinder Mission

    NASA Technical Reports Server (NTRS)

    Stebbins, Robin

    2009-01-01

    LISA Pathfinder (formerly known as SMART-2) is a European Space Agency (ESA) mission designed to pave the way for the joint ESA/NASA Laser Interferometer Space Antenna (LISA) mission by testing in flight the critical technologies required for spaceborne gravitational wave detection: it will put two test masses in a near-perfect gravitational free-fall and control and measure their motion with unprecedented accuracy. LISA Pathfinder is currently in the integration and test phase of the development, and is due to be launched on a dedicated launch vehicle in late 2011, with first results on the performance of the system being available approx 6 months later. This poster will describe the mission in detail, give the current status of the spacecraft development, and highlight the future milestones in the integration and test campaign.

  4. Mars Pathfinder [foldout].

    PubMed

    1997-12-01

    The following foldout present images and analysis from the Mars Pathfinder Mission that are discussed in seven subsequent Reports. The center is a four-page panorama of the surface of Mars around the lander (Plate 1). The back of the foldout contains surface images (Plate 7), a different perspective of the landing site (Plate 2), rover targets (Plate 3), locations of rocks and other features (Plate 6) and data analysis (Plates 4, 4, 8, 9, and 10). PMID:9411794

  5. Cytokines Online Pathfinder Encyclopaedia

    NSDL National Science Digital Library

    The Cytokines Online Pathfinder Encyclopaedia (COPE) is the brainchild of Horst Ibelgaufts of Germany's Ludwig-Maximilians-Universit't Gene Center. Part super-glossary, part general guide to the "jungles, morasses, and deserts of cytokine-land," this incredibly extensive Web site helps researchers stay on top of newly identified proteins and previously identified but recently reevaluated proteins. As of February 2003, COPE contains over 8,700 entries, which have been mercifully grouped into sub-glossaries by subject: apoptosis, cell lines, chemokines, cytokine topics, hematology, metalloproteinases virokines, viroceptors, and virulence factors.

  6. Delta II Mars Pathfinder

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Final preparations for lift off of the DELTA II Mars Pathfinder Rocket are shown. Activities include loading the liquid oxygen, completing the construction of the Rover, and placing the Rover into the Lander. After the countdown, important visual events include the launch of the Delta Rocket, burnout and separation of the three Solid Rocket Boosters, and the main engine cutoff. The cutoff of the main engine marks the beginning of the second stage engine. After the completion of the second stage, the third stage engine ignites and then cuts off. Once the third stage engine cuts off spacecraft separation occurs.

  7. Effects of changing temperatures on coral reef health: Implications for management

    Microsoft Academic Search

    Elizabeth Rose Selig

    2008-01-01

    Human-induced climate change has already led to substantial changes in a variety of ecosystems. Coral reefs are particularly vulnerable to rises in ocean temperature as a result of climate change because they already live near their thermal limits. However, we know little about the spatial patterns of temperature anomalies, areas of greater than usual temperature, which cause coral mortality and

  8. Pathfinder Rover Atop Mermaid Dune

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Mars Pathfinder Lander camera image of Sojourner Rover atop the Mermaid 'dune' on Sol 30. Note the dark material excavated by the rover wheels. These, and other excavations brought materials to the surface for examination and allowed estimates of mechanical properties of the deposits.

    NOTE: original caption as published in Science Magazine

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

  9. LISA Pathfinder ground testing

    NASA Astrophysics Data System (ADS)

    Guzman, Felipe; LISA Pathfinder Team

    2010-01-01

    The space-based gravitational wave observatory LISA is a joint NASA-ESA mission that requires challenging technology to ensure pure geodetic trajectories of test masses and the interferometric measurement of distance variations between them. The LISA Pathfinder mission is an ESA-launched technology demonstrator of key LISA subsystems such as spacecraft control with micronewton thrusters, test mass drag-free control, and precision laser interferometry between free-flying test masses. Ground testing of pre-flight hardware of the Gravitational Reference Sensor and Optical Metrology subsystems is currently ongoing. Studies have been carried out on very sensitive torsion pendulums that effectively reproduce a free-fall condition for the test mass within a horizontal plane in the lab, down to frequencies < 0.1 mHz. Thermal gradient induced effects, impact of gas molecules, noisy charging, surface charge patches, and other effects have been investigated and their physical models consolidated. A final upper limit on non-modeled disturbances has also been obtained within one order of magnitude of LISA requirements at 1 mHz. The interferometry system has also been extensively studied to identify noise sources and develop approaches to mitigate them. Engineering models of the optical bench, laser head and laser modulators have been interconnected and tested for functionality and noise level in closed-loop operation, demonstrating the required optical metrology sensitivity to test mass displacement. This poster presents the current status in the development and implementation of LISA Pathfinder pre-flight systems and latest results of the ongoing ground testing efforts.

  10. Metatranscriptome Sequencing of a Reef-building Coral Elucidates Holobiont Community Gene Functions in Health and Disease

    NASA Astrophysics Data System (ADS)

    Timberlake, S.; Helbig, T.; Fernando, S.; Penn, K.; Alm, E.; Thompson, F.; Thompson, J. R.

    2012-12-01

    The coral reefs of the Abrolhos Bank of Brazil play a vital ecological role in the health of the Southern Atlantic Ocean, but accelerating rates of disease, particularly white plague, threaten this ecosystem. Thus, an understanding of white plague disease and diagnostic tests for it are urgently needed. The coral animal is associated with a distinct microbiome, a diverse assemblage of eukaryotes, bacteria, and viruses. That these microbes have a great influence on the health of the coral has been long known, however, most of their functions are still mysterious. While recent studies have contrasted healthy and white-plague-associated communities, the causative agents and mechanisms of the disease remain unknown. We collected fragments of healthy and diseased corals, as well as post-disease skeleton, from 12 colonies of the genus Mussismilia, the major component of the reef structure in the Abrolhos bank, and increasingly, a victim of white-plague disease. Fragments were flash-frozen in situ, and prepped for culture-free high throughput sequencing of gene transcripts with the Illumina II-G. While the membership of the microbial communities associated with coral has been previously described, the a coral holobiont community's gene function has, to date, never been assayed by this powerful approach. We designed a bioinformatics pipeline to analyze the short-read data from this complex sample: identifying the functions of genes expressed in the holobiont, and describing the active community's taxonomic composition. We show that gene functions expressed by the coral's bacterial assemblage are distinct from those of the underlying skeleton, and we highlight differences in the disease samples. We find that gene markers for the dissimilatory sulfate reduction pathway more abundant in the disease state, and we further quantify this difference with qPCR. Finally, we report the abundant expression of highly repetitive transcripts in the diseased coral samples, and highlight other coral host genes whose expression differs in this disease. Our work provides a first glimpse into coral holobiont community gene function and its deviations in disease. Moreover, we hope that our bioinformatic protocol, designed to cope with the challenges of short-read transcriptomics from complex ecosystems with no close reference, will be a useful template to further understanding of the gene functions and ecological partnerships in coral reefs and other complex ecosystems.

  11. Hillary Clinton visits Pathfinder projects in Brazil.

    PubMed

    1996-01-01

    In October 1995, US First Lady Hillary Clinton visited a maternity hospital in Salvador, Brazil, in which a family planning (FP)/reproductive health program has been administered by Pathfinder International since 1981 with funding from USAID. During her tour of the facility, Clinton learned about the high degree of unmet need for FP in the region which results from a lack of sufficient resources to meet demand. Clinton, in turn, praised the state of Bahia for its emphasis on FP in low-income areas. PMID:12179683

  12. Coral Reefs

    NSDL National Science Digital Library

    Description of coral reef environment for high school level and higher. Page is chock full of fantastic photographs each featuring a descriptive caption. Topics discussed include ecology, symbiosis, and predator defense. The site features many different species and stages of coral from all over the globe, and also many of the fishes that are associated with coral reefs.

  13. Coral Reefs

    NSDL National Science Digital Library

    2012-08-03

    This problem-based learning (PBL) module prompts students to address coral reef destruction and think about biodiversity worldwide. Students identify possible sources of coral reef destruction, examine conflicting evidence, evaluate possible courses of action, and make recommendations. As they do this, students look at man's impact on the global environment. Two versions of the PBL module are provided. The middle school scenario focuses on the question: is the cumulative weight of human activities changing the environment and destroying coral reefs—one of Earth’s last great areas of biodiversity? The high school scenario focuses on the question: what are the pros and cons of artificial reefs—are they effective in preserving biodiversity that can be lost when natural coral reefs are destroyed? This module is part of Exploring the Environment.

  14. Mars Pathfinder Landing Site Workshop

    NASA Technical Reports Server (NTRS)

    Golombek, Matthew (editor)

    1994-01-01

    The Mars Pathfinder Project is an approved Discovery-class mission that will place a lander and rover on the surface of the Red Planet in July 1997. The Mars Pathfinder Landing Site Workshop was designed to allow the Mars scientific community to provide input as to where to land Pathfinder on Mars. The workshop was attended by over 60 people from around the United States and from Europe. Over 20 landing sites were proposed at the workshop, and the scientific questions and problems concerning each were addressed. The workshop and the discussion that occured during and afterward have significantly improved the ability to select a scientifically exciting but safe landing site on Mars.

  15. Date: November 10, 2006 To: Becky Shortland, Gray's Reef Reserve

    E-print Network

    Rosemond, Amy Daum

    -making. Given that the effects of land-based pollution on the health of reefs offshore are cause for concern-borne pollution in rivers and streams is the effect that these pollutants and nutrients have on coral reefs and Phosphorous (found commonly from fertilizer runoff) can all have negative effects on the health of reefs

  16. Coral Reefs

    NSDL National Science Digital Library

    2012-10-20

    In this video, Jonathan examines the biology of coral reefs and their importance to the marine ecosystem. Please see the accompanying lesson plan that discusses pH and ocean acidification for educational objectives, discussion points and classroom activities.

  17. Coral Reefs

    NSDL National Science Digital Library

    NBC Learn

    2010-10-07

    Scientists are studying coral reefs around the world to discover the impact that warmer temperatures and increased carbon dioxide may have on the life cycle of corals. "Changing Planet" is produced in partnership with the National Science Foundation.

  18. LISA Pathfinder: mission and status

    Microsoft Academic Search

    F. Antonucci; M. Armano; H. Audley; G. Auger; M. Benedetti; P. Binetruy; C. Boatella; J. Bogenstahl; D. Bortoluzzi; P. Bosetti; M. Caleno; A. Cavalleri; M. Cesa; M. Chmeissani; G. Ciani; A. Conchillo; G. Congedo; I. Cristofolini; M. Cruise; K. Danzmann; F. De Marchi; M. Diaz-Aguilo; I. Diepholz; G. Dixon; R. Dolesi; N. Dunbar; J. Fauste; L. Ferraioli; D. Fertin; W. Fichter; E. Fitzsimons; M. Freschi; A. García Marin; C. García Marirrodriga; R. Gerndt; L. Gesa; F. Gilbert; D. Giardini; C. Grimani; A. Grynagier; B. Guillaume; F. Guzmán; I. Harrison; G. Heinzel; M. Hewitson; D. Hollington; J. Hough; D. Hoyland; M. Hueller; J. Huesler; O. Jeannin; O. Jennrich; P. Jetzer; B. Johlander; C. Killow; X. Llamas; I. Lloro; A. Lobo; R. Maarschalkerweerd; S. Madden; D. Mance; I. Mateos; P. W. McNamara; J. Mendes; E. Mitchell; A. Monsky; D. Nicolini; D. Nicolodi; M. Nofrarias; F. Pedersen; M. Perreur-Lloyd; A. Perreca; E. Plagnol; P. Prat; G. D. Racca; B. Rais; J. Ramos-Castro; J. Reiche; J. A. Romera Perez; D. Robertson; H. Rozemeijer; J. Sanjuan; A. Schleicher; M. Schulte; D. Shaul; L. Stagnaro; S. Strandmoe; F. Steier; T. J. Sumner; A. Taylor; D. Texier; C. Trenkel; D. Tombolato; S. Vitale; G. Wanner; H. Ward; S. Waschke; P. Wass; W. J. Weber; P. Zweifel

    2011-01-01

    LISA Pathfinder, the second of the European Space Agency's Small Missions for Advanced Research in Technology (SMART), is a dedicated technology demonstrator for the joint ESA\\/NASA Laser Interferometer Space Antenna (LISA) mission. The technologies required for LISA are many and extremely challenging. This coupled with the fact that some flight hardware cannot be fully tested on ground due to Earth-induced

  19. Gravitational science with LISA Pathfinder

    Microsoft Academic Search

    C. Trenkel; S. Kemble

    2009-01-01

    We investigate the potential of conducting interesting gravitational science experiments with LISA Pathfinder, by executing well defined de-orbiting manoeuvres following the nominal mission. Preliminary work suggests that the residual control authority of the micropropulsion system is sufficient to follow trajectories that cross the region surrounding the Sun-Earth saddle point, and also include one or multiple Earth flybys. Crossing the saddle

  20. Pathfinder's rover, airbags, & Martian terrain

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This is one of the first pictures taken by the camera on the Mars Pathfinder lander shortly after its touchdown at 10:07 AM Pacific Daylight Time on July 4, 1997. The small rover, named Sojourner, is seen in the foreground in its position on a solar panel of the lander. The white material on either side of the rover is part of the deflated airbag system used to absorb the shock of the landing. Between the rover and the horizon is the rock-strewn martian surface. Two hills are seen in the right distance, profiled against the light brown sky.

    Pathfinder, a low-cost Discovery mission, is the first of a new fleet of spacecraft that are planned to explore Mars over the next ten years. Mars Global Surveyor, already en route, arrives at Mars on September 11 to begin a two year orbital reconnaissance of the planet's composition, topography, and climate. Additional orbiters and landers will follow every 26 months.

    The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  1. Pathfinder Teaching and Learning Units.

    ERIC Educational Resources Information Center

    Hawaii Univ., Honolulu. Sea Grant Program.

    This collection of teaching units were selected from materials developed during the Operation Pathfinder Institutes (OPI) which took place in the Pacific region between 1994 and 1999. The institutes were intended to provide upper elementary and middle school science teachers with an opportunity to develop a deeper understanding of the marine…

  2. Spacetime Metrology with LISA Pathfinder

    NASA Astrophysics Data System (ADS)

    Congedo, Giuseppe

    2012-04-01

    LISA is the proposed ESA-NASA gravitational wave detector in the 0.1 mHz - 0.1 Hz band. LISA Pathfinder is the down-scaled version of a single LISA arm. The arm - named Doppler link - can be treated as a differential accelerometer, measuring the relative acceleration between test masses. LISA Pathfinder - the in-flight test of the LISA instrumentation - is currently in the final implementation and planned to be launched in 2014. It will set stringent constraints on the ability to put test masses in geodesic motion to within the required differential acceleration of 3times10^{-14} m s^{-2} Hz^{-1/2} and track their relative motion to within the required differential displacement measurement noise of 9times10^{-12} m Hz^{-1/2}, around 1 mHz. Given the scientific objectives, it will carry out - for the first time with such high accuracy required for gravitational wave detection - the science of spacetime metrology, in which the Doppler link between two free-falling test masses measures the curvature. This thesis contains a novel approach to the calculation of the Doppler response to gravitational waves. It shows that the parallel transport of 4-vectors records the history of gravitational wave signals. In practice, the Doppler link is implemented with 4 bodies in LISA and 3 bodies in LISA Pathfinder. To compensate for noise sources a control logic is implemented during the measurement. The closed-loop dynamics of LISA Pathfinder can be condensed into operators acting on the motion coordinates, handling the couplings, as well as the cross-talks. The scope of system identification is the optimal calibration of the instrument. This thesis describes some data analysis procedures applied to synthetic experiments and shows the relevance of system identification for the success of LISA Pathfinder in demonstrating the principles of spacetime metrology for all future space-based missions.

  3. Desert Pathfinder at Work

    NASA Astrophysics Data System (ADS)

    2005-09-01

    The Atacama Pathfinder Experiment (APEX) project celebrates the inauguration of its outstanding 12-m telescope, located on the 5100m high Chajnantor plateau in the Atacama Desert (Chile). The APEX telescope, designed to work at sub-millimetre wavelengths, in the 0.2 to 1.5 mm range, passed successfully its Science Verification phase in July, and since then is performing regular science observations. This new front-line facility provides access to the "Cold Universe" with unprecedented sensitivity and image quality. After months of careful efforts to set up the telescope to work at the best possible technical level, those involved in the project are looking with satisfaction at the fruit of their labour: APEX is not only fully operational, it has already provided important scientific results. "The superb sensitivity of our detectors together with the excellence of the site allow fantastic observations that would not be possible with any other telescope in the world," said Karl Menten, Director of the group for Millimeter and Sub-Millimeter Astronomy at the Max-Planck-Institute for Radio Astronomy (MPIfR) and Principal Investigator of the APEX project. ESO PR Photo 30/05 ESO PR Photo 30/05 Sub-Millimetre Image of a Stellar Cradle [Preview - JPEG: 400 x 627 pix - 200k] [Normal - JPEG: 800 x 1254 pix - 503k] [Full Res - JPEG: 1539 x 2413 pix - 1.3M] Caption: ESO PR Photo 30/05 is an image of the giant molecular cloud G327 taken with APEX. More than 5000 spectra were taken in the J=3-2 line of the carbon monoxide molecule (CO), one of the best tracers of molecular clouds, in which star formation takes place. The bright peak in the north of the cloud is an evolved star forming region, where the gas is heated by a cluster of new stars. The most interesting region in the image is totally inconspicuous in CO: the G327 hot core, as seen in methanol contours. It is a truly exceptional source, and is one of the richest sources of emission from complex organic molecules in the Galaxy (see spectrum at bottom). Credit: Wyrowski et al. (map), Bisschop et al. (spectrum). Millimetre and sub-millimetre astronomy opens exciting new possibility in the study of the first galaxies to have formed in the Universe and of the formation processes of stars and planets. In particular, APEX allows astronomers to study the chemistry and physical conditions of molecular clouds, that is, dense regions of gas and dust in which new stars are forming. Among the first studies made with APEX, astronomers took a first glimpse deep into cradles of massive stars, observing for example the molecular cloud G327 and measuring significant emission in carbon monoxide and complex organic molecules (see ESO PR Photo 30/05). The official inauguration of the APEX telescope will start in San Pedro de Atacama on September, 25th. The Ambassadors in Chile of some of ESO's member states, the Intendente of the Chilean Region II, the Mayor of San Pedro, the Executive Director of the Chilean Science Agency (CONICYT), the Presidents of the Communities of Sequitor and Toconao, as well as representatives of the Ministry of Foreign Affairs and Universities in Chile, will join ESO's Director General, Dr. Catherine Cesarsky, the Chairman of the APEX Board and MPIfR director, Prof. Karl Menten, and the Director of the Onsala Space Observatory, Prof. Roy Booth, in a celebration that will be held in San Pedro de Atacama. The next day, the delegation will visit the APEX base camp in Sequitor, near San Pedro, from where the telescope is operated, as well as the APEX site on the 5100m high Llano de Chajnantor.

  4. A Pathfinder for Juvenile Diabetes

    Microsoft Academic Search

    Maxine Streeter

    2000-01-01

    Organized especially for students, parents, and guardians of Lincoln High School in Dallas, Texas, this pathfinder includes fiction and nonfiction books with helpful information on the research, diagnosis, and treatment of diabetes. Fiction is added for leisurely entertainment and comparison to reality. Care and self-help informational books; low-fat, high-fiber recipe books; and magazines especially for diabetics are given. It provides

  5. Multispectral Imaging from Mars PATHFINDER

    NASA Technical Reports Server (NTRS)

    Ferrand, William H.; Bell, James F., III; Johnson, Jeffrey R.; Bishop, Janice L.; Morris, Richard V.

    2007-01-01

    The Imager for Mars Pathfinder (IMP) was a mast-mounted instrument on the Mars Pathfinder lander which landed on Mars Ares Vallis floodplain on July 4, 1997. During the 83 sols of Mars Pathfinders landed operations, the IMP collected over 16,600 images. Multispectral images were collected using twelve narrowband filters at wavelengths between 400 and 1000 nm in the visible and near infrared (VNIR) range. The IMP provided VNIR spectra of the materials surrounding the lander including rocks, bright soils, dark soils, and atmospheric observations. During the primary mission, only a single primary rock spectral class, Gray Rock, was recognized; since then, Black Rock, has been identified. The Black Rock spectra have a stronger absorption at longer wavelengths than do Gray Rock spectra. A number of coated rocks have also been described, the Red and Maroon Rock classes, and perhaps indurated soils in the form of the Pink Rock class. A number of different soil types were also recognized with the primary ones being Bright Red Drift, Dark Soil, Brown Soil, and Disturbed Soil. Examination of spectral parameter plots indicated two trends which were interpreted as representing alteration products formed in at least two different environmental epochs of the Ares Vallis area. Subsequent analysis of the data and comparison with terrestrial analogs have supported the interpretation that the rock coatings provide evidence of earlier martian environments. However, the presence of relatively uncoated examples of the Gray and Black rock classes indicate that relatively unweathered materials can persist on the martian surface.

  6. Coral Reef Ecosystems: Ecosystems in Crisis

    NSDL National Science Digital Library

    National Science Teachers Association (NSTA)

    2007-03-28

    This Science Object is the fourth of four Science Objects in the Coral Reef Ecosystems SciPack. It explores the natural and human causes of ecosystem stress. Human beings live near coral ecosystems and use them in a variety of ways. Increasing amounts of stress is brought on these ecosystems as humans continue to modify the surrounding environment as a result of population growth, technology, and consumption. Human destruction of habitats through direct harvesting, pollution, atmospheric changes, and other factors is threatening the stability and overall health of many coral reefs. Human activities may also exacerbate the impact of natural disturbances on coral reefs or compromise the ability of the reef to recover from events such as hurricanes, tsunamis, or disease. Learning Outcomes:? Describe ways in which human activities directly impact coral reef ecosystems (resource and recreational uses).? Describe ways in which human activities indirectly impact coral reef ecosystems (by changing the physical conditions, pollution, changes in the water chemistry, etc.).? Explain how human activity may decrease the reefs ability to recover from natural occurrences. ? Explain the effects of increased predation or disease on a reef ecosystem.? Describe the effect of habitat loss on the reef ecosystem.? Describe the effects of weather and climate change on a healthy and weakened reef ecosystem.

  7. SCUBA Diver Specialization and Behavior Norms at Coral Reefs

    Microsoft Academic Search

    Laura E. Anderson; David K. Loomis

    2011-01-01

    SCUBA diving is an increasingly popular activity that provides a number of benefits to coastal communities. However, the sustainability of recreational diving on coral reefs is largely dependent on the health of reef ecosystems. Divers can minimize their impacts to coral reefs through responsible diving behaviors, which are in part guided by social norms. The behavioral obligation and sanction components

  8. Jurassic Reef Park

    NSDL National Science Digital Library

    Dr. Reinhold Leinfelder of the University of Stuttgart, Germany created this interesting site in English and German, offering a "virtual trip to the reefs of the Jurassic Period." In the Introduction, viewers will find background material and comparisons of modern and ancient reefs. Further information is provided in the sections on reef architecture, reef formation, Jurassic reefs, and reefs and global climate change. Although the English language is slightly quirky, the content and images more than compensate, making this a worthwhile site.

  9. Software Aids Visualization Of Mars Pathfinder Mission

    NASA Technical Reports Server (NTRS)

    Weidner, Richard J.

    1996-01-01

    Report describes Simulator for Imager for Mars Pathfinder (SIMP) computer program. SIMP generates "virtual reality" display of view through video camera on Mars lander spacecraft of Mars Pathfinder mission, along with display of pertinent textual and graphical data, for use by scientific investigators in planning sequences of activities for mission.

  10. MARS PATHFINDER ENCAPSULATION IN SAEF-2

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The Mars Pathfinder and mated PAM-D upper stage booster are ready for transfer from the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2) on KSC to Launch Complex 17 on Cape Canaveral Air Station. Uppermost is the Mars Pathfinder assembly, with its lander encased in a protective aeroshell attached to the circular cruise stage. Lowermost on the workstand is the PAM-D booster that will give the Pathfinder the final 'kick' to send it on its way to Mars. Once at Launch Complex (LC) 17, the Pathfinder will be encased in a protective fairing before being mated to the Delta II expendable launch vehicle that will loft it into orbit. Mars Pathfinder is slated for liftoff from LC 17B on Dec. 2.

  11. Pathfinder on lakebed preparing for test flight

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Support crew are shown preparing the Pathfinder solar-powered aircraft on Rogers Dry Lake at NASA's Dryden Flight Research Center, Edwards, California. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

  12. Pathfinder - flight preparation on lakebed at sunrise

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Crew members prepare the Pathfinder solar-powered aircraft for its first flight on Rogers Dry Lake at NASA's Dryden Flight Research Center, Edwards, California, after its configuration was changed from 8 motors to 6. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

  13. Project O.R.B (Operation Reef Ball): Creating Artificial Reefs, Educating the Community

    NASA Astrophysics Data System (ADS)

    Phipps, A.

    2012-04-01

    The Project O.R.B. (Operation Reef Ball) team at South Plantation High School's Everglades Restoration & Environmental Science Magnet Program is trying to help our ailing south Florida coral reefs by constructing, deploying, and monitoring designed artificial reefs. Students partnered with the Reef Ball Foundation, local concrete companies, state parks, Girl Scouts, Sea Scouts, local universities and environmental agencies to construct concrete reef balls, each weighing approximately 500 lbs (227 kg). Students then deployed two artificial reefs consisting of over 30 concrete reef balls in two sites previously permitted for artificial reef deployment. One artificial reef was placed approximately 1.5 miles (2.4 km) offshore of Golden Beach in Miami-Dade County with the assistance of Florida Atlantic University and their research vessel. A twin reef was deployed at the mouth of the river in Oleta River State Park in Miami. Monitoring and maintenance of the sites is ongoing with semi-annual reports due to the Reef Ball Foundation and DERM (Department of Environmental Resource Management) of Miami-Dade County. A second goal of Project O.R.B. is aligned with the Florida Local Action Strategy, the Southeast Florida Coral Reef Initiative, and the U.S. Coral Reef Task Force, all of which point out the importance of awareness and education as key components to the health of our coral reefs. Project O.R.B. team members developed and published an activity book targeting elementary school students. Outreach events incorporate cascade learning where high school students teach elementary and middle school students about various aspects of coral reefs through interactive "edu-tainment" modules. Attendees learn about water sampling, salinity, beach erosion, surface runoff, water cycle, ocean zones, anatomy of coral, human impact on corals, and characteristics of a well-designed artificial reef. Middle school students snorkel on the artificial reef to witness first-hand the success of this artificial reef. Over 3,000 students have been reached through the educational outreach endeavors of Project O.R.B. This successful STEM project models the benefits of partnerships with universities, local K-12 public schools and community conservation organizations and provides students with authentic learning experiences. Students are able to have a positive impact on their local coral reef environment, their peers and their community through this comprehensive service-learning project.

  14. Web Reef Advisory System

    NSDL National Science Digital Library

    The Web Reef Advisory System (WRAS) was developed by ReefBase and Reef Check, in collaboration with the Coastal Resources Center at the University of Rhode Island and the Department of Biological Sciences at the University of Southern California, as "an online application to input, view, and analyse Reef Check survey data. It calculates indicators of how good or bad a shape a particular reef is in, and what the underlying causes may be, based on Reef Check surveys." WRAS allows users to view, analyze, and add (registration required) data. Please note that site users must complete a free and brief registration process before they are granted full access to the Reef Check website. Other site offerings include an interactive Reef Check GIS feature (see website for browser requirements), and The Reef Check Barometer of Global Reef Condition which provides assessments of different regions based on Reef Check Indicators.

  15. Mapping Oyster Reef Habitats in Mobile Bay

    NASA Technical Reports Server (NTRS)

    Bolte, Danielle

    2011-01-01

    Oyster reefs around the world are declining rapidly, and although they haven t received as much attention as coral reefs, they are just as important to their local ecosystems and economies. Oyster reefs provide habitats for many species of fish, invertebrates, and crustaceans, as well as the next generations of oysters. Oysters are also harvested from many of these reefs and are an important segment of many local economies, including that of Mobile Bay, where oysters rank in the top five commercial marine species both by landed weight and by dollar value. Although the remaining Mobile Bay oyster reefs are some of the least degraded in the world, projected climate change could have dramatic effects on the health of these important ecosystems. The viability of oyster reefs depends on water depth and temperature, appropriate pH and salinity levels, and the amount of dissolved oxygen in the water. Projected increases in sea level, changes in precipitation and runoff patterns, and changes in pH resulting from increases in the amount of carbon dioxide dissolved in the oceans could all affect the viability of oyster reefs in the future. Human activities such as dredging and unsustainable harvesting practices are also adversely impacting the oyster reefs. Fortunately, several projects are already under way to help rebuild or support existing or previously existing oyster reefs. The success of these projects will depend on the local effects of climate change on the current and potential habitats and man s ability to recognize and halt unsustainable harvesting practices. As the extent and health of the reefs changes, it will have impacts on the Mobile Bay ecosystem and economy, changing the resources available to the people who live there and to the rest of the country, since Mobile Bay is an important national source of seafood. This project identified potential climate change impacts on the oyster reefs of Mobile Bay, including the possible addition of newly viable habitats in the southeastern regions of the Bay.

  16. Low cost approach to Mars Pathfinder

    NASA Astrophysics Data System (ADS)

    Spear, Anthony J.

    1995-10-01

    Mars Pathfinder, launching in December '96 and landing in July '97, will demo a low cost delivery system to the surface of Mars. Historically, spacecraft that orbit or land on a distant body carry a large amount of fuel for braking. Mars Pathfinder, thrusting only for navigation, enters directly into the Martian atmosphere, aerobrakes with its aeroshell, deploys a parachute at 10 km above the surface and, within 100 m off the surface, ignites solid rockets for final braking prior to deployment of air bags which cushion touchdown. After landing, petals open to upright the lander, exposing solar panels to the sun. Even though the lander and rover are expected to last longer, the major objectives of Mars Pathfinder, demonstrating EDL (Entry, Descent, Landing) and lander-rover surface operations, will occur within the first few days, at which time panoramic images of the surface will be transmitted and the rover will be deployed to conduct both mobility tests and rock composition measurements. While Mars Pathfinder is primarily an engineering demo, it accomplishes a focused, exciting set of science investigations with a stereo, multi-color lander imager; atmospheric instrumentation, used as a weather station after landing; and the rover with cameras and the APXS (Alpha Proton X-ray Spectrometer). This paper features Mars Pathfinder's approach to innovative and cost effective mission accomplishment, under a development cost cap. Mars Pathfinder is pathfinding a new way of doing business at NASA and JPL for small, low cost, Discovery class missions.

  17. The Pathfinder Chemical Transfer Propulsion Program

    NASA Technical Reports Server (NTRS)

    Hannum, Ned P.; Berkopec, Frank D.; Zurawski, Robert L.

    1989-01-01

    Pathfinder is a research and technology initiative by the National Aeronautics and Space Administration (NASA) intended to strengthen the technology base of the United States civil space program in preparation for future space exploration missions. Pathfinder begins in FY-89. One of the four major thrusts is the Chemical Transfer Propulsion program which will provide the propulsion technology for high performance, liquid oxygen/liquid hydrogen expander cycle engines which are expected to be operated and maintained in space. These advanced engines will enhance or enable a variety of future space exploration missions. The goals and objectives, management, technical plan, and technology transfer for the Chemical Transfer Propulsion element of Pathfinder are described.

  18. National Pathfinder Survey on Children’s Oral Health in Italy: Pattern and Severity of Caries Disease in 4-Year-Olds

    Microsoft Academic Search

    G. Campus; G. Solinas; L. Strohmenger; M. G. Cagetti; A. Senna; L. Minelli; S. Majori; M. T. Montagna; D. Reali; P. Castiglia

    2009-01-01

    This paper describes the dental health status of Italian 4-year-olds in 2004\\/2005 and analyzes the association between caries in preschool children and some background characteristics in children and parents. Caries was recorded according to WHO criteria. 5,538 subjects were examined. Information on the children’s and their parents’ social, behavioral, ethnic and demographic status was obtained through a series of closed

  19. NOAA's Coral Reef

    NSDL National Science Digital Library

    Portal to NOAA programs on coral reef research, management, protection. Online booklet describes corals, importance of reefs as habitat, value to humans, natural and human impacts. Site offers outreach and online educational materials, including lesson plans and list of things you can do. Search coral reef data and publications, find funding opportunities, review state of U.S. reefs, local and national action plans. Provides links to related sites, including coral reef photo library, international initiatives.

  20. Gravitational science with LISA Pathfinder

    NASA Astrophysics Data System (ADS)

    Trenkel, C.; Kemble, S.

    2009-03-01

    We investigate the potential of conducting interesting gravitational science experiments with LISA Pathfinder, by executing well defined de-orbiting manoeuvres following the nominal mission. Preliminary work suggests that the residual control authority of the micropropulsion system is sufficient to follow trajectories that cross the region surrounding the Sun-Earth saddle point, and also include one or multiple Earth flybys. Crossing the saddle point region may allow tests of Modified Newtonian Dynamics (MOND), while the flybys may potentially shed some light on the so-called flyby anomaly. We present some sample trajectories and discuss the limitations of the current model. Finally, we discuss the work required to take these ideas from the proof of principle presented here, to a concrete proposal for an extended mission.

  1. Mars Pathfinder Two-Dimensional Model

    NSDL National Science Digital Library

    2012-08-03

    This activity is about the Mars Pathfinder spacecraft. Using cardboard and other materials, learners will create a two dimensional model of the spacecraft. A diagram with approximate measures of each component is provided.

  2. Power and pyro subsystems for Mars Pathfinder

    SciTech Connect

    Shirbacheh, M. [California Inst. of Tech., Pasadena, CA (United States). Jet Propulsion Lab.

    1997-12-31

    The Power and Pyro Subsystem (PPS) for Mars Pathfinder was designed to support the spacecraft activities during Launch, Cruise, Entry and Landing and Mars operation phases of the mission. The key design constraints were cost, volume and mass. The PPS consists of solar arrays, batteries and power electronics. This paper describes the Mars Pathfinder mission, key requirements on PPS, and PPS system architecture and description of each element of the PPS system.

  3. Pathfinder-Plus flight in Hawaii

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Pathfinder-Plus flight in Hawaii June 2002 AeroVironment's Pathfinder-Plus solar-powered flying wing recently flew a three-flight demonstration of its ability to relay third-generation cell phone and video signals as well as provide Internet linkage. The two pods underneath the center section of the wing carried the advanced two-way telecom package, developed by Japanese telecommunications interests.

  4. The Mars Pathfinder ASI\\/MET Investigation

    Microsoft Academic Search

    J. Schofield; D. Crisp; C. Labaw; C. Mahoney; A. Seiff; J. Murphy; J. Mihalov; G. Wilson; R. Haberle; J. Tillman; J. Barnes

    1996-01-01

    On July 4th 1997, the Mars Pathfinder spacecraft will enter the martian atmosphere, land in the Ares Vallis region, and obtain the first in-situ measurements of the atmosphere and surface since the Viking mission more than 20 years ago. In addition to a Stereo Imager and an Alpha Proton X-Ray spectrometer, the Pathfinder Lander will carry an Atmospheric Structure and

  5. Coral Reef Ecosystems: The Living Reef

    NSDL National Science Digital Library

    National Science Teachers Association (NSTA)

    2006-11-01

    This Science Object is the first of four Science Objects in the Coral Reef Ecosystems SciPack. It explores the unique and diverse ecosystem of the coral reef. Coral reefs are very complex systems that create one of the largest structures on Earth of biological origins. Thousands of coral species exist in oceans worldwide. Reef-building corals remain on the same spot of the sea floor through their entire lives and have developed reproductive, feeding, and social behaviors suited to their situation. As they grow, reefs provide structural habitats for hundreds to thousands of different organisms. Learning Outcomes:? Identify coral polyp structures and describe their functions.? Describe photosynthesis in the coral environment.? Describe the evolution of a typical reef system.? Use the shape of an individual coral to identify its common name, and classify entire coral reef ecosystems based on shape and location. ? Describe the process of coral polyp reproduction and growth.? Identify how the features and/or behavioral strategies of coral reef inhabitants enable them to survive in coral reef environments.

  6. LISA Pathfinder instrument data analysis

    NASA Astrophysics Data System (ADS)

    Guzman, Felipe

    LISA Pathfinder (LPF) is an ESA-launched demonstration mission of key technologies required for the joint NASA-ESA gravitational wave observatory in space, LISA. As part of the LPF interferometry investigations, analytic models of noise sources and corresponding noise subtrac-tion techniques have been developed to correct for effects like the coupling of test mass jitter into displacement readout, and fluctuations of the laser frequency or optical pathlength difference. Ground testing of pre-flight hardware of the Optical Metrology Subsystem is currently ongoing at the Albert Einstein Institute Hannover. In collaboration with NASA Goddard Space Flight Center, the LPF mission data analysis tool LTPDA is being used to analyze the data product of these tests. Furthermore, the noise subtraction techniques and in-flight experiment runs for noise characterization are being defined as part of the mission experiment master plan. We will present the data analysis outcome of pre-flight hardware ground tests and possible noise subtraction strategies for in-flight instrument operations.

  7. Battery study for the Mars Environmental Survey (MESUR) Pathfinder

    NASA Technical Reports Server (NTRS)

    Dawson, Stephen F.; Otzinger, B.; Perrone, D.; Distefano, Sal; Halpert, Gerald

    1994-01-01

    Viewgraphs on the battery study for the Mars Environmental Survey (MESUR) Pathfinder are presented. Topics covered include: MESUR pathfinder introduction; power subsystem concept; battery technology selection; mission battery performance; cell/battery baseline design; charge methodology; and proposed testing.

  8. Coral Reef Connections

    NSDL National Science Digital Library

    Coral Reef Connections explores the different reef zones of the Great Barrier Reef in Australia, the biodiversity that has evolved there, and the interactions between the many species, their environment, and each other. Users can navigate through a virtual "dive" on the reef, select various organisms, and view the types of relationships they have with each other. Links to related topics and web activities are included.

  9. TOVS Pathfinder product validation and intercomparison

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Validation and intercomparison is an essential part of the Pathfinder program. Since its organization within the International TOVS Working Group, the TOVS community has continuously emphasized this aspect of the product retrieval problem. In the previous sections of this report, the TOVS Pathfinder SWG has recommended a careful and coherent reorganization and archiving of TOVS radiance data, and three distinct pathways for deriving product variables from this TOVS radiance archive. The importance in taking this multiple path approach to creating climate datasets rests in our firm belief that there is now global 'absolute truth' data for any of the derived physical parameters. Each of the selected methods is based upon a different set of assumptions. The challenge in interpreting Pathfinder data is to determine what alterations in the physical attributes of the environment contribute to evidence of global change extracted from observed or derived Pathfinder datasets. The Pathfinder validation and intercomparison activity must include validation of the forward problem, by which one calculates an estimate of upwelling radiance information from given earth and atmospheric data, and validation of the inverse problem, by which one calculates estimates of earth and atmospheric information from given upwelling satellite spectral radiance data.

  10. Planetary Coral Reef Foundation

    NSDL National Science Digital Library

    The Planetary Coral Reef Foundation was founded in 1991 to address the growing crisis of destruction of coral reefs. Topics include the PCRF's mission, its research activities at sea and in space, wastewater recycling, conservation tips that can help preserve reefs, and the organization's ship, R.V. Heraclitus.

  11. Journey to the Reef

    ERIC Educational Resources Information Center

    Bryson, Linda

    2010-01-01

    Despite their experiences with a cartoon sponge, most elementary students know little about the diverse inhabitants of coral reefs. Therefore, with vivid photography and video, diverse coral reef inhabitants were brought to life for the author's fifth-grade students. Students shared their knowledge in language arts and even explored coral reefs in…

  12. Dynamic Pathfinders: Leveraging Your OPAC to Create Resource Guides

    ERIC Educational Resources Information Center

    Hunter, Ben

    2008-01-01

    Library pathfinders are a time-tested method of leading library users to important resources. However, paper-based pathfinders suffer from space limitations, and both paper-based and Web-based pathfinders require frequent updates to keep up with new library acquisitions. This article details a step-by-step method to create an online dynamic…

  13. A Comparison of Efficiency in Pathfinding Algorithms in Game Development

    E-print Network

    Schaefer, Marcus

    A Comparison of Efficiency in Pathfinding Algorithms in Game Development A Thesis Submitted Tomuro #12;2 A Comparison of Efficiency in Pathfinding Algorithms in Game Development Nikhil Krishnaswamy done to assess the efficiency of three different pathfinding algorithms in a game-like environment

  14. Life and death on the coral reef: an ecological perspective on scholarly publishing in the health sciences*†

    PubMed Central

    Forsman, Rick B.

    2005-01-01

    Objective: Reflecting patterns evident in past Janet Doe lectures, the 2004 address draws on the foundations of biology to provide a model that offers insights into the advent of electronic publications and choices for the future. Setting: The lecture sketches a picture of the fragile relationships found in complex ecosystems and illustrates how such interdependencies function in the environment of the coral reef. Analysis: Deriving lessons from the marine world, the lecture then shifts to a description of similarities in the realm of scholarly publishing, the impact of digital innovations in the marketplace, and the controversies and choices inherent in open access publications. Conclusions: Lessons from ecology and publishing lead to the conclusion that librarians must take action and risks in this time of dramatic environmental change. PMID:15685268

  15. Overhead view of Pathfinder Landing Site

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image, prepared by Pathfinder scientists at NASA/ Ames Research Center, is a view of the landing site from above. Seen in the lower right is Mermaid dune, with its long axis oriented northwest-southeast and its steeper side, the presumed slipface, toward the southwest. Dunes like Mermaid, the depositional tails and erosional moats associated with rocks in the area, and the fluted and polished surfaces on several boulders at the landing site all indicate an effective wind that blows from the northeast to the southwest.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

  16. Periodontal status among adolescents in Georgia. A pathfinder study.

    PubMed

    Levin, Liran; Margvelashvili, Vladimer; Bilder, Leon; Kalandadze, Manana; Tsintsadze, Nino; Machtei, Eli E

    2013-01-01

    Objectives. The aim of the present pathfinder study was to screen and map the periodontal status of Georgian population in accordance with the guidelines of the World Health Organization for population based surveys. Methods. During 2012, a pathfinder study was conducted to collect this data. For the periodontal portion of the study, 15-year-old school children were examined in the capital city of Tbilisi as well as in two other large cities and 4 smaller villages. All participants were examined by a trained dental team in a classroom using a dental mirror and a periodontal probe. Periodontal examination included plaque scores, calculus scores, probing depth measurements and bleeding on probing. These measurements were recorded for the Ramfjord index teeth. Results. A total of 397 15-year-old participants were examined in this pathfinder study. There were 240 females (60.45%) and 157 males (39.55%). Of the total participants 196 (49.37%) were urban adolescents while 201 (50.63%) were from rural communities. Mean probing depth was 3.34 ± 0.57 mm with a range of 1 to 10 mm; a relatively high proportion (34.26%) of these subjects presented with at least one site with pockets of 5 mm or deeper. Males presented with greater plaque, calculus and probing depths than females. When urban and rural populations were compared, urban participants presented with more plaque, probing depths and bleeding on probing. Greater pocket depths were found to be related to the presence of plaque calculus and bleeding on probing. Conclusions. Overall, rather high incidences of periodontal pockets ? 5 mm were detected in this population. This data should serve to prepare further more detailed epidemiological studies that will serve to plan and implement prevent and treat strategies for periodontal diseases in Georgia and also help make manpower decisions. PMID:24109543

  17. Coral Reef Adventure

    NSDL National Science Digital Library

    MacGillivray Freeman

    This site from MacGillivray Freeman Films presents information about the movie "Coral Reef Adventure," as well as an assortment of links about coral reefs. In particular, the section on Learning About Reefs features a virtual dive that highlights marine life at various depths. This section also provides educational resources including a teacher's guide and learning activities. The site also includes links to many organizations that provide support for reversing the current worldwide decline in coral reef ecosystems and to finding new and sustainable solutions for managing the world's coral reefs.

  18. Dioramas: Andros Coral Reef

    NSDL National Science Digital Library

    In the shallow waters off the coast of Andros Island in the Caribbean, corals of all shapes and sizes form the Andros Reef, one of the largest barrier reefs in the world. Like other coral reefs, Andros was created by massive colonies of coral polyps, which are small, soft-bodied animals. These creatures have hard skeletons that form much of the structure of a coral reef. The once thriving Andros Reef is now threatened. In the past, antler-shaped elkhorn coral dominated the reef, with multiple colonies extending continuously for long stretches. Throughout the Caribbean today, this species exists primarily in isolated colonies and scientists estimate that in certain places, up to 95 percent of elkhorn coral has died. This site describes the formation of the reef along with the present problems.

  19. Subterranean Groundwater Nutrient Input to Coastal Oceans and Coral Reef Sustainability

    Microsoft Academic Search

    A. Paytan

    2003-01-01

    Coral reefs are often referred to as the tropical rain forests of the oceans because of their high productivity and biodiversity. Recent observations in coral reefs worldwide have shown clear degradation in water quality and coral reef health and diversity. The implications of this are severe, including tremendous economic losses mostly though fishing and tourism. Nutrient loading has been implicated

  20. Pathfinder Landing Site in Color

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 14 May 2004 This image of the Mars Pathfinder Landing site was acquired July 17, 2002, during northern spring.

    The THEMIS VIS camera is capable of capturing color images of the martian surface using its five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from the use of multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    Image information: VIS instrument. Latitude 19.4, Longitude 326.8 East (33.2 West). 38 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  1. Strategy for selecting Mars Pathfinder landing sites

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald; Kuzmin, Ruslin O.

    1994-01-01

    A strategy for Pathfinder site selection must be developed that is fundamentally different from most previous considerations. At least two approaches can be identified. In one approach, the objective is to select a site representing a key geologic unit on Mars, i.e., a unit that is widespread, easily recognized, and used frequently as a datum in various investigations. The second approach is to select a site that potentially affords access to a wide variety of rock types. Because rover range is limited, rocks from a variety of sources must be assembled in a small area for sampling. Regardless of the approach taken in site selection, the Pathfinder site should include eolian deposits and provisions should be made to obtain measurements on soils. A recommended approach for selecting the Mars Pathfinder landing site is to identify a deltaic deposit, composed of sediments derived from sources of various ages and geologic units that shows evidence of eolian activity. The site should be located as close as possible to the part of the outwash where rapid deposition occurred because the likelihood of 'sorting' by size and composition increases with distance, decreasing the probability of heterogeneity. In addition, it is recommended that field operation tests be conducted to gain experience and insight into conducting science with Pathfinder.

  2. Regenerative fuel cell systems for project pathfinder

    NASA Technical Reports Server (NTRS)

    Huff, J. R.; Hedstrom, J.; Vanderborgh, N. E.; Prokopius, P.

    1989-01-01

    The objectives of a surface power program, an element of the exploration thrust of the Pathfinder project, and plans for meeting them are outlined. Technological assessment and tradeoff studies of fuel cell and electrolyzer technologies suitable for use in a regenerative fuel cell are described. The viability of proton exchange membranes (PEM) in meeting the system requirements is discussed.

  3. The Mars Pathfinder Wheel Abrasion Experiment

    Microsoft Academic Search

    Dale C. Ferguson; David M. Wilt; Aloysius F. Hepp; Joseph C. Kolecki; Mark W. Siebert; Phillip P. Jenkins; David A. Scheiman; Navid S. Fatemi; Richard W. Hoffman

    2001-01-01

    On board the Mars Pathfinder spacecraft, launched in December of 1996, was a small roving vehicle named Sojourner. On Sojourner was an experiment to determine the abrasive characteristics of the Martian surface, called the Wheel Abrasion Experiment (WAE). The experiment worked as follows: one of the wheels of the rover had a strip of black anodized aluminum bonded to the

  4. Pathfinding by Peripheral Pioneer Neurons in Grasshoppers

    Microsoft Academic Search

    David Bentley; Haig Keshishian

    1982-01-01

    Grasshopper neurons accurately project axons across long distances between peripheral structures and the central nervous system. Nerve-trunk pathways followed by these axons are established early in embryogenesis by pioneer neurons. Growth cones from the first pioneers navigate along a chain of cells to the CNS. The placement of these cells may constitute the initial guidance mechanism underlying long-distance pathfinding.

  5. Free-Flight Experiments in LISA Pathfinder

    NASA Technical Reports Server (NTRS)

    Thorpe, J. I.; Cutler, C. J.; Hewitson, M.; Jennrich, O.; Maghami, P.; Paczkowski, S.; Russano, G.; Vitale, S.; Weber, W. J.

    2014-01-01

    The LISA Pathfinder mission will demonstrate the technology of drag-free test masses for use as inertial references in future space-based gravitational wave detectors. To accomplish this, the Pathfinder spacecraft will perform drag-free flight about a test mass while measuring the acceleration of this primary test mass relative to a second reference test mass. Because the reference test mass is contained within the same spacecraft, it is necessary to apply forces on it to maintain its position and attitude relative to the spacecraft. These forces are a potential source of acceleration noise in the LISA Pathfinder system that are not present in the full LISA configuration. While LISA Pathfinder has been designed to meet it's primary mission requirements in the presence of this noise, recent estimates suggest that the on-orbit performance may be limited by this 'suspension noise'. The drift-mode or free-flight experiments provide an opportunity to mitigate this noise source and further characterize the underlying disturbances that are of interest to the designers of LISA-like instruments. This article provides a high-level overview of these experiments and the methods under development to analyze the resulting data.

  6. Mars Pathfinder, Science Results, Geology and Geomorphology

    NSDL National Science Digital Library

    This NASA-hosted site is a section of the Mars Pathfinder Science Results Directory with a specific emphasis on the geologic and geomorphic characteristics observed. Many photos and satellite images are available, with the option to view and download full size images. Scientific theories are offered as to the probable geomorphic agents sculpting Mars' surface.

  7. Free-flight experiments in LISA Pathfinder

    NASA Astrophysics Data System (ADS)

    Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Brandt, N.; Bursi, A.; Caleno, M.; Cavalleri, A.; Cesarini, A.; Cruise, M.; Cutler, C.; Danzmann, K.; Diepholz, I.; Dolesi, R.; Dunbar, N.; Ferraioli, L.; Ferroni, V.; Fitzsimons, E.; Freschi, M.; Gallegos, J.; García Marirrodriga, C.; Gerndt, R.; Gesa, LI; Gibert, F.; Giardini, D.; Giusteri, R.; Grimani, C.; Harrison, I.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hueller, M.; Huesler, J.; Inchauspé, H.; Jennrich, O.; Jetzer, P.; Johlander, B.; Karnesis, N.; Kaune, B.; Korsakova, N.; Killow, C.; Lloro, I.; Maarschalkerweerd, R.; Madden, S.; Maghami, P.; Mance, D.; Martín, V.; Martin-Porqueras, F.; Mateos, I.; McNamara, P.; Mendes, J.; Mendes, L.; Moroni, A.; Nofrarias, M.; Paczkowski, S.; Perreur-Lloyd, M.; Petiteau, A.; Pivato, P.; Plagnol, E.; Prat, P.; Ragnit, U.; Ramos-Castro, J.; Reiche, J.; Romera Perez, J. A.; Robertson, D.; Rozemeijer, H.; Russano, G.; Sarra, P.; Schleicher, A.; Slutsky, J.; Sopuerta, C. F.; Sumner, T.; Texier, D.; Thorpe, J.; Trenkel, C.; Tu, H. B.; Vetrugno, D.; Vitale, S.; Wanner, G.; Ward, H.; Waschke, S.; Wass, P.; Wealthy, D.; Wen, S.; Weber, W.; Wittchen, A.; Zanoni, C.; Ziegler, T.; Zweifel, P.

    2015-05-01

    The LISA Pathfinder mission will demonstrate the technology of drag-free test masses for use as inertial references in future space-based gravitational wave detectors. To accomplish this, the Pathfinder spacecraft will perform drag-free flight about a test mass while measuring the acceleration of this primary test mass relative to a second reference test mass. Because the reference test mass is contained within the same spacecraft, it is necessary to apply forces on it to maintain its position and attitude relative to the spacecraft. These forces are a potential source of acceleration noise in the LISA Pathfinder system that are not present in the full LISA configuration. While LISA Pathfinder has been designed to meet it's primary mission requirements in the presence of this noise, recent estimates suggest that the on-orbit performance may be limited by this ‘suspension noise’. The drift-mode or free-flight experiments provide an opportunity to mitigate this noise source and further characterize the underlying disturbances that are of interest to the designers of LISA-like instruments. This article provides a high-level overview of these experiments and the methods under development to analyze the resulting data.

  8. The Magnetic Properties Experiments on Mars Pathfinder

    NASA Astrophysics Data System (ADS)

    Knudsen, J. M.; Gunnlaugsson, H. P.; Hviid, S. F.; Madsen, M. B.

    1996-09-01

    A remarkable result from the Viking missions was the discovery that the Martian soil is highly magnetic, in the sense that the soil is attracted by permanent magnets. Both the strong and weak magnets on the Viking landers were saturated with dust throughout the mission. Appropriate limits for the spontaneous magnetization sigma_S were advanced: 1 Am(2) (kg soil)(-1) < sigma_S < 7 Am(2) (kg soil)(-1) . The essential difference between the Magnet Arrays for Mars Pathfinder and the Viking Magnetic Properties Experiment is that Magnet Arrays on Pathfinder will include magnets of lower strengths that the weakest Viking magnet. The five magnets consist of small ring magnets concentric with oppositely polarized cylindrical magnets. The outer diameter of the ring magnets is 18 mm. Discrete (single phase) particles of strongly magnetic minerals (gamma -Fe2O3 or Fe3O4) will stick to all five magnets, while composite (multiphase) particles will stick preferentially to the strongest magnets. Two Magnet Arrays are placed on the Pathfinder lander, with a distance of 1180 and 1450 mm, respectively, from the Imager for Mars Pathfinder (IMP). The magnets will attract airborne dust, and the dust on the magnets will be periodically viewed by the IMP. The images transmitted to Earth are the data on which conclusions on the magnetic properties of the dust will be based. Besides the Magnet Arrays the Pathfinder lander carries two other types of magnets. The Tip Plate Magnet is placed at a distance of 10 cm from the IMP, and thus allows a rather high resolution imaging of the dust clinging to the magnet. The Ramp Magnets are placed near the end of the ramps by which the micro-rover will descend to the surface. The dust on the Ramp Magnets will be studied by the APX-spectrometer of the micro-rover.

  9. Coral Reef Ecosystems

    NSDL National Science Digital Library

    National Science Teachers Association (NSTA)

    2007-03-28

    The Coral Reef Ecosystems SciPack explores the unique and diverse ecosystem of the coral reef. The focus is on Standards and Benchmarks related to populations and ecosystems using coral reefs and their immediate environment as an example. Because the Standards and Benchmarks present the concepts of populations and ecosystems generically, without reference to a specific ecosystem or the organisms in the system, coral reefs are used to provide the context through which concepts in a marine ecosystem are explored.In addition to comprehensive inquiry-based learning materials tied to Science Education Standards and Benchmarks, the SciPack includes the following additional components:? Pedagogical Implications section addressing common misconceptions, teaching resources and strand maps linking grade band appropriate content to standards. ? Access to one-on-one support via e-mail to content "Wizards".? Final Assessment which can be used to certify mastery of the concepts.Learning Outcomes:Coral Reef Ecosystems: The Living Reef? Identify coral polyp structures and describe their functions.? Describe photosynthesis in the coral environment.? Describe the evolution of a typical reef system.? Use the shape of an individual coral to identify its common name, and classify entire coral reef ecosystems based on shape and location. ? Describe the process of coral polyp reproduction and growth.? Identify how the features and/or behavioral strategies of coral reef inhabitants enable them to survive in coral reef environments.Coral Reef Ecosystems: The Abiotic Setting? Identify the characteristics of an ecosystem, and describe the interdependence between biotic and abiotic features in an ecosystem.? Describe how the following abiotic factors provide coral with the energy needed to survive and grow within their ecosystem: sunlight, water, oxygen, and carbon dioxide.? Describe the optimal environmental conditions for coral reef growth, and explain the process of coral reef development (including the role of available sunlight and calcium).? Explain how the following environmental factors might affect coral ecosystems: increase in dissolved CO2, changes in global temperatures, increase in ocean water turbidity through water pollution.Coral Reef Ecosystems: Interdependence? Identify and label key components of food chains and food webs in a coral reef ecosystem.? Describe key relationships among plants and animals in the coral reef ecosystem: predator and prey relationships, producer and consumer relationships, and symbiotic relationships (mutualism, commensalisms, parasitism).? Recognize the direction that energy travels through food chains and food webs.? Explain that materials (chemical elements) and natural resources are recycled in coral reef ecosystems and reappear in different forms.? Describe the primary ecological succession events within a typical coral reef ecosystem.Coral Reef Ecosystems: Ecosystems in Crisis? Describe ways in which human activities directly impact coral reef ecosystems (resource and recreational uses).? Describe ways in which human activities indirectly impact coral reef ecosystems (by changing the physical conditions, pollution, changes in the water chemistry, etc.).? Explain how human activity may decrease the reefs ability to recover from natural occurrences. ? Explain the effects of increased predation or disease on a reef ecosystem.? Describe the effect of habitat loss on the reef ecosystem.? Describe the effects of weather and climate change on a healthy and weakened reef ecosystem.

  10. Coral Reef Ecosystems: The Abiotic Setting

    NSDL National Science Digital Library

    National Science Teachers Association (NSTA)

    2006-11-01

    This Science Object is the second of four Science Objects in the Coral Reef Ecosystems SciPack. It investigates the abiotic characteristics that affect the coral reef ecosystem. The number and kinds of organisms found along each reef depend on the physical conditions of the environment and resources available, including food, light, water quality, temperature, and other organisms living in the reef. If conditions change significantly due to changes in climate, loss of food sources, excessive predation, or loss of habitat, the health and stability of the ecosystem will be affected. Like many complex systems, coral ecosystems tend to have cyclic fluctuations around a state of rough equilibrium. In the long run, if conditions remain reasonably constant a coral ecosystem can be stable for hundreds of years. Learning Outcomes:? Identify the characteristics of an ecosystem, and describe the interdependence between biotic and abiotic features in an ecosystem.? Describe how the following abiotic factors provide coral with the energy needed to survive and grow within their ecosystem: sunlight, water, oxygen, and carbon dioxide.? Describe the optimal environmental conditions for coral reef growth, and explain the process of coral reef development (including the role of available sunlight and calcium).? Explain how the following environmental factors might affect coral ecosystems: increase in dissolved CO2, changes in global temperatures, increase in ocean water turbidity through water pollution.

  11. Mars Pathfinder Landing Site and Surroundings

    NASA Technical Reports Server (NTRS)

    2007-01-01

    NASA's Mars Pathfinder landed on Mars on July 4, 1997, and continued operating until Sept. 27 of that year. The landing site is on an ancient flood plain of the Ares and Tiu outflow channels. The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter took an image on Dec. 21, 2006, that provides unprecedented detail of the geology of the region and hardware on the surface.

    [figure removed for brevity, see original site] HiRISE Image This is the entire image. The crater at center bottom was unofficially named 'Big Crater' by the Pathfinder team. Its wall was visible from Pathfinder, located 3 kilometers (2 miles) to the north. The two bright features to the upper left of Big Crater are the 'Twin Peaks,' also observed by Pathfinder. The bright mound to the upper right of the Twin Peaks is 'North Knob,' seen in Pathfinder images as peaking over the horizon.

    At this scale there is no obvious geologic evidence of an ancient flood. Rather, impact craters dominate the scene, attesting to an old surface. The age is probably on the order of 1.8 billion to 3.5 billion years, when the Ares and Tiu floods are estimated to have occurred. Wind-formed linear ripples and dunes are seen throughout and are concentrated within craters. Sets of polygonal ridges of enigmatic origin are seen east of the Pathfinder lander. Rocks are visible over the entire image, with heavy concentrations near fresh-looking craters. Most of them are probably blocks tossed outward by crater-forming impacts.

    The complete image is centered at 19.1 degrees north latitude, 326.8 degrees east longitude. The range to the target site was 284.7 kilometers (177.9 miles). At this distance the image scale is 28.5 centimeters (11 inches) per pixel, so objects about 85 centimeters (33 inches) across are resolved. The image shown here has been map-projected to 25 centimeters (10 inches) per pixel. North is up. The image was taken at a local Mars time of 3:35 p.m., and the scene is illuminated from the west with a solar incidence angle of 52 degrees, thus the sun was about 38 degrees above the horizon. At a solar longitude of 154.0 degrees, the season on Mars is northern summer.

    [figure removed for brevity, see original site] Landing Site Region This is a close-up of the area in the vicinity of the Pathfinder landing site. Major features are named. The white box outlines the area of the image, discussed next, where hardware is seen.

    [figure removed for brevity, see original site] Hardware on the Surface This image shows the Pathfinder lander on the surface. Zooming in, one can discern the ramps, science deck, and portions of the airbags on the Pathfinder lander. (See next image for closer view.) The back shell and parachute are to the south, and four features that may be portions of the heat shield are identified. Two of these were visible from Pathfinder. At the time of that mission, the nearest object was provisionally identified as the back shell. However, analysis of the HiRISE image and reinterpretation of Pathfinder images, plus an improved understanding of how hardware looks on the Martian surface based on ground-level and orbital images of the Mars Exploration Rover landing sites, indicate that the glint is bright enough that it may be insulating material from inside the heat shield. The back shell and parachute were out of sight behind a ridge from Pathfinder's ground view. One of the three bright features, identified as heat shield debris, was also identified during the Pathfinder mission.

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Annotated Version Unannotated Version Topographic Map of Landing Site Region Portions of the HiRISE image are overlaid onto color-coded topographic maps constructed by the U.S. Geological Survey from stereo images acquired by the Imager for Mars Pathfinder on the lander. The white feature at the

  12. Caribbean-wide decline in carbonate production threatens coral reef growth

    PubMed Central

    Perry, Chris T.; Murphy, Gary N.; Kench, Paul S.; Smithers, Scott G.; Edinger, Evan N.; Steneck, Robert S.; Mumby, Peter J.

    2013-01-01

    Global-scale deteriorations in coral reef health have caused major shifts in species composition. One projected consequence is a lowering of reef carbonate production rates, potentially impairing reef growth, compromising ecosystem functionality and ultimately leading to net reef erosion. Here, using measures of gross and net carbonate production and erosion from 19 Caribbean reefs, we show that contemporary carbonate production rates are now substantially below historical (mid- to late-Holocene) values. On average, current production rates are reduced by at least 50%, and 37% of surveyed sites were net erosional. Calculated accretion rates (mm?year?1) for shallow fore-reef habitats are also close to an order of magnitude lower than Holocene averages. A live coral cover threshold of ~10% appears critical to maintaining positive production states. Below this ecological threshold carbonate budgets typically become net negative and threaten reef accretion. Collectively, these data suggest that recent ecological declines are now suppressing Caribbean reef growth potential. PMID:23360993

  13. Uncovering the connectivity of coral reef systems via Lagrangian Coherent Structures

    NASA Astrophysics Data System (ADS)

    Leclair, Matthieu; Lowe, Ryan; Zang, ???Zhenlin; Ivey, Gregory; Peacock, Thomas

    2015-04-01

    There has been a staggering decline in the health of coral reef ecosystems worldwide over the past century, driven by anthropogenic influences, natural processes, and overall climate change. The future of coral reefs depends largely on their ability to recover from catastrophic events, which in turn crucially relies on the ability of reef larval populations to supply and restore damaged reefs. Improving quantitative predictions of reef larval transport and connectivity has thus emerged as a high priority research area in coral reef science. Ocean circulation models are being increasingly utilized in conjunction with particle tracking methods to provide spatially explicit predictions of larval transport within reef systems. The current major drawback of this approach is that it does not elucidate the underlying yet dynamic flow structures that drive reef connectivity. Recently, however, novel Lagrangian-based analysis approaches have been developed to identify the hidden coherent structures that govern material transport in spatiotemporally complex flow fields. Here we apply these methods to investigate the connectivity within a complex coral reef system, using the UNESCO World Heritage Ningaloo Reef in Australia as a case study. Our study demonstrates how this new approach identifies the dominant flow structures present on the reef, thereby uncovering connectivity and advocating a new practical framework for investigating and understanding how ocean processes shape the ecological transport in and around coral reefs. The technique can prove particularly valuable in supporting the design of Marine Protected Areas that are intended to safeguard the future of coral reefs and other ocean ecosystems.

  14. Ocean World: Coral Reefs

    NSDL National Science Digital Library

    Texas A&M University presents Ocean World, a Web-based educational resource for oceanography. The feature on coral reefs has the most direct life sciences application, with easy-to-navigate sections about the coral animal, coral reefs as the rainforests of the sea, symbiosis, ecosystem services, and coral reef threats and conservation. The Web site also includes a handy hypertext glossary, an interactive quiz, and annotated links to interesting Web sites, including sites that provide real-time reef images and data. While no formal lesson plans are provided, this Web site could be easily incorporated to a related classroom module for a range of grade levels.

  15. The Virtual Silurian Reef

    NSDL National Science Digital Library

    This virtual museum exhibit features an interactive diorama highlighting a variety of sea creatures from reef ecosystems of the Silurian period in Wisconsin and Illinois. Topics include an overview of the geology and geologic history, fossil preservation, and plate tectonics. There are maps of the distribution of the reefs; a graphic analysis of biodiversity in these ecosystems; a discussion of the relation between environmental factors, reef size, and growth; and information on the museum's laboratory study of the reef samples and how they constructed the diorama.

  16. Assessment of Mars Pathfinder landing site predictions

    USGS Publications Warehouse

    Golombek, M.P.; Moore, H.J.; Haldemann, A.F.C.; Parker, T.J.; Schofield, J.T.

    1999-01-01

    Remote sensing data at scales of kilometers and an Earth analog were used to accurately predict the characteristics of the Mars Pathfinder landing site at a scale of meters. The surface surrounding the Mars Pathfinder lander in Ares Vallis appears consistent with orbital interpretations, namely, that it would be a rocky plain composed of materials deposited by catastrophic floods. The surface and observed maximum clast size appears similar to predictions based on an analogous surface of the Ephrata Fan in the Channeled Scabland of Washington state. The elevation of the site measured by relatively small footprint delay-Doppler radar is within 100 m of that determined by two-way ranging and Doppler tracking of the spacecraft. The nearly equal elevations of the Mars Pathfinder and Viking Lander 1 sites allowed a prediction of the atmospheric conditions with altitude (pressure, temperature, and winds) that were well within the entry, descent, and landing design margins. High-resolution (~38 m/pixel) Viking Orbiter 1 images showed a sparsely cratered surface with small knobs with relatively low slopes, consistent with observations of these features from the lander. Measured rock abundance is within 10% of that expected from Viking orbiter thermal observations and models. The fractional area covered by large, potentially hazardous rocks observed is similar to that estimated from model rock distributions based on data from the Viking landing sites, Earth analog sites, and total rock abundance. The bulk and fine-component thermal inertias measured from orbit are similar to those calculated from the observed rock size-frequency distribution. A simple radar echo model based on the reflectivity of the soil (estimated from its bulk density), and the measured fraction of area covered by rocks was used to approximate the quasi-specular and diffuse components of the Earth-based radar echos. Color and albedo orbiter data were used to predict the relatively dust free or unweathered surface around the Pathfinder lander compared to the Viking landing sites. Comparisons with the experiences of selecting the Viking landing sites demonstrate the enormous benefit the Viking data and its analyses and models had on the successful predictions of the Pathfinder site. The Pathfinder experience demonstrates that, in certain locations, geologic processes observed in orbiter data can be used to infer surface characteristics where those processes dominate over other processes affecting the Martian surface layer. Copyright 1999 by the American Geophysical Union.

  17. U.S. Coral Reef Taskforce

    NSDL National Science Digital Library

    Government task force created in 1998 to research, monitor and conserve coral reefs. Site includes: background on coral reef habitats; reef ecology and environmental requirements; environmental requirements of reefs; reef functions and significance; natural and human threats to reefs. Also covered are: Task Force actions; policies and partnerships; and the National Action Plan for Coral Reef Conservation.

  18. Reef Education Evaluation: Environmental Knowledge and Reef Experience

    ERIC Educational Resources Information Center

    Stepath, Carl M.

    2005-01-01

    Background: The Reef education evaluation: environmental knowledge and reef experience report concerns PhD research about marine education, and the investigation of learning with high school students and the effect of coral reef monitoring marine experiential education interventions. The effectiveness of classroom learning and reef trips were…

  19. Potential landing sites for Mars Pathfinder

    NASA Technical Reports Server (NTRS)

    Kuzmin, Ruslan O.; Landheim, R.; Greeley, Ronald

    1994-01-01

    In addition to a better understanding of the geological evolution of Mars, new techniques for processing available data have emerged, new data have been acquired, and the engineering approaches for placing spacecraft on the surface have evolved. Selection of the Mars Pathfinder landing site must take these issues into account, along with mission constraints. An advantage of Mars Pathfinder is the rover for sampling surface materials over a range of tens of meters. However, engineering constraints and the limited scientific payload of this mission require new approaches for landing site selection. One approach is to select sites exhibiting a wide variety of rocks near the lander. An alternative approach is to select sites in which the regional geology consists of a single rock type representing a key datum for the geological study of Mars, and is uniformly distributed within the landing ellipse.

  20. Parameter estimation in LISA Pathfinder operational exercises

    NASA Astrophysics Data System (ADS)

    Nofrarias, M.; Ferraioli, L.; Congedo, G.; Hueller, M.; Armano, M.; Diaz-Aguiló, M.; Grynagier, A.; Hewitson, M.; Vitale, S.

    2012-06-01

    The LISA Pathfinder data analysis team has been developing in the last years the infrastructure and methods required to run the mission during flight operations. These are gathered in the LTPDA toolbox, an object oriented MATLAB toolbox that allows all the data analysis functionalities for the mission, while storing the history of all operations performed to the data, thus easing traceability and reproducibility of the analysis. The parameter estimation methods in the toolbox have been applied recently to data sets generated with the OSE (Off-line Simulations Environment), a detailed LISA Pathfinder non-linear simulator that will serve as a reference simulator during mission operations. These simulations, so called operational exercises, are the last verification step before translating these experiments into tele-command sequences for the spacecraft, producing therefore very relevant datasets to test our data analysis methods. In this contribution we report the results obtained with three different parameter estimation methods during one of these operational exercises.

  1. Materials Adherence Experiment on Mars Pathfinder: Early results

    SciTech Connect

    Landis, G.A. [Ohio Aerospace Inst., Cleveland, OH (United States); Jenkins, P.P. [Essential Research Inc., Cleveland, OH (United States); Hunter, G. [NASA Lewis Research Center, Cleveland, OH (United States)

    1997-12-31

    The Materials Adherence Experiment (MAE) on the Pathfinder Sojourner rover will measure the dust deposition rate. By August, the Sojourner Rover on Mars Pathfinder will have completed its primary mission, and the experiment will have data on dust deposition during the first three weeks of operation on Mars. This paper will present the initial data from the experiment. This will be the first presentation of the results from the Pathfinder MAE experiment.

  2. Selection of the Mars Pathfinder landing site

    Microsoft Academic Search

    M. P. Golombek; R. A. Cook; H. J. Moore; T. J. Parker

    1997-01-01

    The Mars Pathfinder spacecraft will land on a depositional fan near the mouth of the catastrophic outflow channel, Ares Val!is (19.5øN, 32.8øW). This site offers the prospect of analyzing a variety of rock types from the ancient cratered highlands, intermediate-age ridged plains, and reworked channel deposits. Analyses of these rocks by Pathffmder instruments will enable first-order scientific questions to be

  3. Pathfinder-Plus aircraft in flight

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The Pathfinder-Plus solar-powered aircraft is shown taking off from a runway, then flying at low altitude over the ocean. The vehicle, which looks like a flying ruler, operates at low airspeed. Among the missions proposed for a solar-powered aircraft are communications relay, atmospheric studies, pipeline monitoring and gas leak detection, environmental monitoring using thermal and radar images, and disaster relief and monitoring.

  4. The Pathfinder image-guided surgical robot.

    PubMed

    Deacon, G; Harwood, A; Holdback, J; Maiwand, D; Pearce, M; Reid, I; Street, M; Taylor, J

    2010-01-01

    This paper first describes the workflow of the Pathfinder image-guided surgical robot that has been designed to replace the stereotactic frame in neurosurgery, and then details the calibration stages employed in order to achieve submillimetre positioning accuracy of a tool tip. The process uses non-linear parameter identification techniques in conjunction with some procedures for camera calibration, which exploit the fact that the camera is mounted to a calibrated robot arm that executes precise motions. PMID:20718271

  5. Modal analysis of PATHFINDER unmanned air vehicle

    Microsoft Academic Search

    T. G. Woehrle; B. W. Costerus; C. L. Lee

    1994-01-01

    An experimental modal analysis was performed on PATHFINDER, a 450-lb, 100-ft wing span, flying-wing-design aircraft powered by solar\\/electric motors. The aircraft was softly suspended and then excited using random input from a long-stroke shaker. Modal data was taken from 92 measurement locations on the aircraft using newly designed, lightweight, tri-axial accelerometers. A conventional PC-based data acquisition system provided data handling.

  6. Mars Pathfinder Project: Planetary Constants and Models

    NASA Technical Reports Server (NTRS)

    Vaughan, Robin

    1995-01-01

    This document provides a common set of astrodynamic constants and planetary models for use by the Mars Pathfinder Project. It attempts to collect in a single reference all the quantities and models in use across the project during development and for mission operations. These models are central to the navigation and mission design functions, but they are also used in other aspects of the project such as science observation planning and data reduction.

  7. Impact of sea-level rise and coral mortality on the wave dynamics and wave forces on barrier reefs.

    PubMed

    Baldock, T E; Golshani, A; Callaghan, D P; Saunders, M I; Mumby, P J

    2014-06-15

    A one-dimensional wave model was used to investigate the reef top wave dynamics across a large suite of idealized reef-lagoon profiles, representing barrier coral reef systems under different sea-level rise (SLR) scenarios. The modeling shows that the impacts of SLR vary spatially and are strongly influenced by the bathymetry of the reef and coral type. A complex response occurs for the wave orbital velocity and forces on corals, such that the changes in the wave dynamics vary reef by reef. Different wave loading regimes on massive and branching corals also leads to contrasting impacts from SLR. For many reef bathymetries, wave orbital velocities increase with SLR and cyclonic wave forces are reduced for certain coral species. These changes may be beneficial to coral health and colony resilience and imply that predicting SLR impacts on coral reefs requires careful consideration of the reef bathymetry and the mix of coral species. PMID:24768171

  8. Capitol Reef Sandstone Cliff

    USGS Multimedia Gallery

    A sandstone cliff within Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  9. Capitol Reef Cliff

    USGS Multimedia Gallery

    A sandstone cliff near the entrance of Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth. The tr...

  10. Capitol Reef Panorama

    USGS Multimedia Gallery

    A panorama of some of the sandstone formations within Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in th...

  11. Capitol Reef Sandstone Monolith

    USGS Multimedia Gallery

    A sandstone monolith within Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  12. Capitol Reef Cliff

    USGS Multimedia Gallery

    A sandstone cliff near the entrance of Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth. This l...

  13. Capitol Reef Cliff

    USGS Multimedia Gallery

    A sandstone cliff near the entrance of Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth.&n...

  14. Reefs in Crisis

    NSDL National Science Digital Library

    This online article, from "The Biodiversity Crisis: Losing What Counts", walks students through the risks humans pose to the survival of coral reefs and conservation efforts. It discusses the forces behind damage to the reefs and recent protection efforts, including the creation of sanctuaries, good land management, and public awareness campaigns.

  15. Create a Coral Reef

    NSDL National Science Digital Library

    In this hands-on OLogy activity, kids learn about coral reefs by building a diorama. Students are introduced to coral polyps and reefs and given illustrated, step-by-step directions that show how to construct a diorama containing models of a brain coral, a sea fan, a sponge, and sea anemones.

  16. ReefBase, A Global Information System on Coarl Reefs

    NSDL National Science Digital Library

    ReefBase

    ReefBase is an online information system dedicated to coral reefs. The site aims to facilitate sustainable management of coral reefs and related coastal/marine environments. Included are data and information on the location, status, threats, monitoring, legislation, and management of coral reefs in 131 countries, extensive data on coral bleaching, a state-of-the-art online mapping-system that allows custom-made maps of coral reefs and related datasets, and an extensive bibliography of publications.

  17. Life on the Reef

    NSDL National Science Digital Library

    This Expeditions Web site takes an in-depth look at life on one of the world's largest barrier reefs. The site begins with a brief explanation of the expedition and what its participants were looking to find. Dive the Reef is an interactive feature that allows students to learn what separates a lagoon from a reef from a shelf. Meet the Scientists has brief biographies of the 14 team members who participated in the expedition. At the Museum is an article that discusses the selection of the barrier reef system of Andros Island as well as the AMNH's long history of Bahamian research. The Reef from Space explains how NASA's computer-enhanced pictures from space contributed to the expedition's findings. The site also includes 12 dispatches written during the expedition, which can be found in the Today from the Bahamas section.

  18. Coral Reef Ecosystems: Interdependence

    NSDL National Science Digital Library

    National Science Teachers Association (NSTA)

    2006-11-01

    This Science Object is the third of four Science Objects in the Coral Reef Ecosystems SciPack. It explores the interdependent relationships between species in the coral reef ecosystem. All populations in the reef ecosystem are a part of and depend on a global food web (a connected set of food chains) through which energy flows in one direction, from the sun into organism and eventually dissipating into the environment as heat. This food web includes ocean plants, the animals that feed on them, and the animals that feed on those animals. Energy is transferred between organisms and their environment along the way. Energy concentration diminishes at each step. The cycles of life continue indefinitely because organisms decompose after death and return food materials to the environment. Learning Outcomes:? Identify and label key components of food chains and food webs in a coral reef ecosystem.? Describe key relationships among plants and animals in the coral reef ecosystem: predator and prey relationships, producer and consumer relationships, and symbiotic relationships (mutualism, commensalisms, parasitism).? Recognize the direction that energy travels through food chains and food webs.? Explain that materials (chemical elements) and natural resources are recycled in coral reef ecosystems and reappear in different forms.? Describe the primary ecological succession events within a typical coral reef ecosystem.

  19. 10th Anniversary Review: a changing climate for coral reefs.

    PubMed

    Lough, Janice M

    2008-01-01

    Tropical coral reefs are charismatic ecosystems that house a significant proportion of the world's marine biodiversity. Their valuable goods and services are fundamental to the livelihood of large coastal populations in the tropics. The health of many of the world's coral reefs, and the goods and services they provide, have already been severely compromised, largely due to over-exploitation by a range of human activities. These local-scale impacts, with the appropriate government instruments, support and management actions, can potentially be controlled and even ameliorated. Unfortunately, other human actions (largely in countries outside of the tropics), by changing global climate, have added additional global-scale threats to the continued survival of present-day coral reefs. Moderate warming of the tropical oceans has already resulted in an increase in mass coral bleaching events, affecting nearly all of the world's coral reef regions. The frequency of these events will only increase as global temperatures continue to rise. Weakening of coral reef structures will be a more insidious effect of changing ocean chemistry, as the oceans absorb part of the excess atmospheric carbon dioxide. More intense tropical cyclones, changed atmospheric and ocean circulation patterns will all affect coral reef ecosystems and the many associated plants and animals. Coral reefs will not disappear but their appearance, structure and community make-up will radically change. Drastic greenhouse gas mitigation strategies are necessary to prevent the full consequences of human activities causing such alterations to coral reef ecosystems. PMID:18175015

  20. ReefBase: A Global Information System on Coral Reefs

    NSDL National Science Digital Library

    Noordeloos, Machiel E.

    ReefBase, a comprehensive Web portal for information on coral reefs, is presented by the World Fish Center based in Malaysia. Intended for use by reef managers, scientists, and the general public, ReefBase aims to "facilitate better understanding of the interdependence between humans and coral reefs, in order to benefit management and conservation efforts of these important resources." ReefBase provides information on coastal and marine resources, coral reef threats, resource management practices, maps and photos, references, and more. Users can quickly search for information organized by country or territory using a convenient dropdown menu. ReefBase is frequently updated; one recent addition is a status report for coral reefs of the southwestern Indian Ocean.

  1. A field effect spacecraft neutralizer for the LISA Pathfinder mission

    Microsoft Academic Search

    B. J. Kent; K. L. Aplin; L. Wang; S. E. Huq; R. Stevens; A. Malik; D. Nicolini

    2005-01-01

    We outline the design, construction and testing of a field effect neutralizer, which provides a source of up to 6 mA of electron emission to maintain charge neutrality for the LISA Pathfinder mission spacecraft. The low mass, low power neutralizer uses silicon field emitter arrays and has been engineered for integration into the LISA Pathfinder micro-propulsion system. The silicon emitters

  2. Pathfinders for Finding Information on Native Americans with Disabilities.

    ERIC Educational Resources Information Center

    Roy, Loriene, Comp.

    This bibliography offers strategies for locating information on selected topics of concern to those working with Native Americans with disabilities. The strategies are arranged in a format called a pathfinder. Each pathfinder follows a similar format, beginning with a brief overview of the topic, followed with an annotated bibliography, and…

  3. Java PathFinder http://cent.xii.jp/

    E-print Network

    Hagiya, Masami

    /path/to 33 #12;JPF · code · > javac */*.java · *.jpf · jpf : > ../jpf-core/bin/jpf foo.jpf 34 #12; #12Java PathFinder 2010.06.14 1 #12; · () http://cent.xii.jp/ tanabe.yoshinori/10/06/jpflect/ 2 #12;Java PathFinder (JPF) · ­ : Java ­ ­ Java Virtual Machine ­ ­ · ­ sourceforge.net ­ NASA

  4. Techniques for identifying dust devils in Mars Pathfinder images

    Microsoft Academic Search

    Stephen M. Metzger; James R. Carr; Jeffrey R. Johnson; Timothy J. Parker; Mark T. Lemmon

    2000-01-01

    Image processing methods used to identify and enhance dust devil features imaged by IMP (Imager for Mars Pathfinder) are reviewed. Spectral differences, visible red minus visible blue, were used for initial dust devil searches, driven by the observation that Martian dust has high red and low blue reflectance. The Martian sky proved to be more heavily dust-laden than pre-Pathfinder predictions,

  5. Mars Pathfinder Wheel Abrasion Experiment Ground Test

    NASA Technical Reports Server (NTRS)

    Keith, Theo G., Jr.; Siebert, Mark W.

    1998-01-01

    The National Aeronautics and Space Administration (NASA) sent a mission to the martian surface, called Mars Pathfinder. The mission payload consisted of a lander and a rover. The primary purpose of the mission was demonstrating a novel entry, descent, and landing method that included a heat shield, a parachute, rockets, and a cocoon of giant air bags. Once on the surface, the spacecraft returned temperature measurements near the Martian surface, atmosphere pressure, wind speed measurements, and images from the lander and rover. The rover obtained 16 elemental measurements of rocks and soils, performed soil-mechanics, atmospheric sedimentation measurements, and soil abrasiveness measurements.

  6. The LISA Pathfinder DMU and Radiation Monitor

    NASA Astrophysics Data System (ADS)

    Canizares, P.; Chmeissani, M.; Conchillo, A.; Diaz–Aguiló, M.; García-Berro, E.; Gesa, L.; Gibert, F.; Grimani, C.; Lloro, I.; Lobo, A.; Mateos, I.; Nofrarias, M.; Ramos-Castro, J.; Sanjuán, J.; Sopuerta, Carlos F.; Araújo, H. M.; Wass, P.

    2011-05-01

    The LISA Pathfinder DMU (Data Management Unit) flight model was formally accepted by ESA and ASD on 11 February 2010, after all hardware and software tests had been successfully completed. The diagnostics items are scheduled to be delivered by the end of 2010. In this paper, we review the requirements and performance of this instrumentation, specially focusing on the Radiation Monitor and the DMU, as well as the status of their programmed use during mission operations, on which work is ongoing at the time of writing.

  7. Pathfinder aircraft taking off - setting new solar powered altitude record

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Pathfinder solar-powered remotely piloted aircraft climbs to a record-setting altitude of 50,567 feet during a flight Sept. 11, 1995, at NASA's Dryden Flight Research Center, Edwards, California. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

  8. Pathfinder on lakebed rolling out for test flight

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Pathfinder research aircraft's wing structure is clearly defined in this photo as personnel from AeroVironment rolled it out onto the lakebed at NASA's Dryden Flight Research Center, Edwards, California, for another test flight. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

  9. Pathfinder - closeup of flight preparation on lakebed at sunrise

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This photo shows the crew preparing the Pathfinder aircraft for a flight from Rogers Dry Lakebed on Edwards Air Force Base, California. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

  10. Coral Reef Ecosystems

    NASA Astrophysics Data System (ADS)

    Yap, Helen T.

    Coral reefs are geological structures of significant dimensions, constructed over millions of years by calcifying organisms. The present day reef-builders are hard corals belonging to the order Scleractinia, phylum Cnidaria. The greatest concentrations of coral reefs are in the tropics, with highest levels of biodiversity situated in reefs of the Indo-West Pacific region. These ecosystems have provided coastal protection and livelihood to human populations over the millennia. Human activities have caused destruction of these habitats, the intensity of which has increased alarmingly since the latter decades of the twentieth century. The severity of this impact is directly related to exponential growth rates of human populations especially in the coastal areas of the developing world. However, a more recently recognized phenomenon concerns disturbances brought about by the changing climate, manifested mainly as rising sea surface temperatures, and increasing acidification of ocean waters due to greater drawdown of higher concentrations of atmospheric carbon dioxide. Management efforts have so far not kept pace with the rates of degradation, so that the spatial extent of damaged reefs and the incidences of localized extinction of reef species are increasing year after year. The major management efforts to date consist of establishing marine protected areas and promoting the active restoration of coral habitats.

  11. Northeast View From Pathfinder Lander - Anaglyph

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This panorama of the region to the northeast of the lander was constructed to support the Sojourner Rover Team's plans to conduct an 'autonomous traverse' to explore the terrain away from the lander after science objectives in the lander vicinity had been met. The large, relatively bright surface in the foreground, about 10 meters (33 feet) from the spacecraft, in this scene is 'Baker's Bench.' The large, elongated rock left of center in the middle distance is 'Zaphod.'

    This anaglyph view was produced by combining the left and right eye mosaics (above) by assigning the left eye view to the red color plane and the right eye view to the green and blue color planes (cyan), to produce a stereo anaglyph mosaic. This mosaic can be viewed in 3-D on your computer monitor or in color print form by wearing red-blue 3-D glasses.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  12. Impact Of Coral Structures On Wave Directional Spreading Across A Shallow Reef Flat - Lizard Island, Northern Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Leon, J. X.; Baldock, T.; Callaghan, D. P.; Hoegh-guldberg, O.; Mumby, P.; Phinn, S. R.; Roelfsema, C. M.; Saunders, M. I.

    2013-12-01

    Coral reef hydrodynamics operate at several and overlapping spatial-temporal scales. Waves have the most important forcing function on shallow (< 5 m) reefs as they drive most ecological and biogeochemical processes by exerting direct physical stress, directly mixing water (temperature and nutrients) and transporting sediments, nutrients and plankton. Reef flats are very effective at dissipating wave energy and providing an important ecosystem service by protecting highly valued shorelines. The effectiveness of reef flats to dissipate wave energy is related to the extreme hydraulic roughness of the benthos and substrate composition. Hydraulic roughness is usually obtained empirically from frictional-dissipation calculations, as detailed field measurements of bottom roughness (e.g. chain-method or profile gauges) is a very labour and time-consuming task. In this study we measured the impact of coral structures on wave directional spreading. Field data was collected during October 2012 across a reef flat on Lizard Island, northern Great Barrier Reef. Wave surface levels were measured using an array of self-logging pressure sensors. A rapid in situ close-range photogrammetric method was used to create a high-resolution (0.5 cm) image mosaic and digital elevation model. Individual coral heads were extracted from these datasets using geo-morphometric and object-based image analysis techniques. Wave propagation was modelled using a modified version of the SWAN model which includes the measured coral structures in 2m by 1m cells across the reef. The approach followed a cylinder drag approach, neglecting skin friction and inertial components. Testing against field data included bed skin friction. Our results show, for the first time, how the variability of the reef benthos structures affects wave dissipation across a shallow reef flat. This has important implications globally for coral reefs, due to the large extent of their area occupied by reef flats, particularly, as global-scale degradation in coral reef health is causing a lowering of reef carbonate production that might lead to a decrease in reef structure and roughness.

  13. The Barrier Reef sediment apron: Tobacco Reef, Belize

    Microsoft Academic Search

    Ian G. Macintyre; Richard R. Graus; Peter N. Reinthal; Mark M. Littler; Diane S. Littler

    1987-01-01

    Sedimentological and biological surveys of the back-reef sediment apron of Tobacco Reef, a continuous segment of the Belizean Barrier Reef, reveal five distinct biogeological zones: (1) coralline-coral-Dictyota pavement, (2) Turbinaria-Sargassum rubble, (3) Laurencia-Acanthophora sand and gravel, (4) bare sand and 95 Thalassia sand. These zones parallel the entire 9-km reef. The distribution of these zones is related to the spatial

  14. Contradicting Barrier Reef relationships for Darwin's Evolution of reef types

    Microsoft Academic Search

    Edward G. Purdy; Edward L. Winterer

    2006-01-01

    The Darwinian progressive subsidence model for the evolution of fringing reefs, barrier reefs and atolls has been generally accepted following the indisputable proof of subsidence provided by drilling results in the Pacific. Nonetheless, there are data that do not fit the expectations of the model, such as the similar lagoon depths of barrier reefs and atolls as opposed to the

  15. Pathfinder landing sites at candidate SNC impact ejection sites

    NASA Technical Reports Server (NTRS)

    Golombek, Matthew P.

    1994-01-01

    If Mars Pathfinder were able to land at a site on Mars from which the SNC meteorites were ejected by impact, the Pathfinder mission would essentially represent a very inexpensive sample return mission. Geologic units that contain four potential impact craters from which SNC meteorites could have been ejected from Mars are accessible to the Mars Pathfinder lander. Determining that SNC meteorites came from a particular spot on Mars raises the intriguing possibility of using Pathfinder as a sample return mission and providing a radiometric age for the considerably uncertain martian crater-age timescale. Pathfinder instruments are capable of determining if the rock type at the landing site is similar to that of one or more of the SNC meteorites, which would strengthen the hypothesis that the SNC meteorites did, in fact, come from Mars. Unfortunately, instrument observations from Pathfinder are probably not capable of determining if the geologic unit sampled by the lander is definitively the unit from which a SNC meteorite came from as opposed to Mars in general or perhaps a particular region on Mars. This abstract evaluates the possibility of landing at potential SNC ejection sites and the ability of Pathfinder to identify the landing site as the place from which an SNC meteorite came.

  16. Private development of artificial reefs 

    E-print Network

    Burns, Arthur Allen

    1978-01-01

    of fish caught in these locations and the rela- tionship of angler hours fished over reef sites and nonreef sites. The catch over these new fishing reefs is usually more than ten-fold the catch over the areas surrounding these reefs. 2 Although...

  17. Feedbacks Between Wave Energy And Declining Coral Reef Structure: Implications For Coastal Morphodynamics

    NASA Astrophysics Data System (ADS)

    Grady, A. E.; Jenkins, C. J.; Moore, L. J.; Potts, D. C.; Burgess, P. M.; Storlazzi, C. D.; Elias, E.; Reidenbach, M. A.

    2013-12-01

    The incident wave energy dissipated by the structural complexity and bottom roughness of coral reef ecosystems, and the carbonate sediment produced by framework-building corals, provide natural shoreline protection and nourishment, respectively. Globally, coral reef ecosystems are in decline as a result of ocean warming and acidification, which is exacerbated by chronic regional stressors such as pollution and disease. As a consequence of declining reef health, many reef ecosystems are experiencing reduced coral cover and shifts to dominance by macroalgae, resulting in a loss of rugosity and thus hydrodynamic roughness. As coral reef architecture is compromised and carbonate skeletons are eroded, wave energy dissipation and sediment transport patterns--along with the carbonate sediment budget of the coastal environment--may be altered. Using a Delft3D numerical model of the south-central Molokai, Hawaii, fringing reef, we simulate the effects of changing reef states on wave energy and sediment transport. To determine the temporally-varying effects of biotic and abiotic stressors such as storms and bleaching on the reef structure and carbonate production, we couple Delft3D with CarboLOT, a model that simulates growth and competition of carbonate-producing organisms. CarboLOT is driven by the Lotka-Volterra population ecology equations and niche suitability principles, and accesses the CarboKB database for region-specific, carbonate-producing species information on growth rates, reproduction patterns, habitat suitability, as well as organism geometries. Simulations assess how changing reef states--which alter carbonate sediment production and reef morphology and thus hydrodynamic roughness--impact wave attenuation and sediment transport gradients along reef-fronted beaches. Initial results suggest that along fringing reefs having characteristics similar to the Molokai fringing reef, projected sea level rise will likely outpace coral reef accretion, and the increased residual wave energy transported to the coast may result in the alteration of alongshore sediment transport gradients and substantial changes to coastal morphology.

  18. Mars Pathfinder Airbag Impact Attenuation System

    NASA Technical Reports Server (NTRS)

    Waye, Donald; Cole, J. Kenneth; Rivellini, Tommaso P.

    1995-01-01

    The Mars Pathfinder spacecraft, scheduled for launch in December 1996, is designed to validate a low cost Entry, Descent, and Landing system and to perform scientific surface operations. The Jet Propulsion Laboratory and Sandia National Laboratories teamed to design, fabricate, test and validate a prototype 0.38 scale model of an airbag impact attenuation system. A computer code was developed to predict the performance of the airbag system. A test program in Sandia's High Altitude Chamber was performed to validate the code and demonstrate the feasibility of the airbag concept and design. In addition, freefall tests were performed at representative velocities to demonstrate the structural integrity of the airbag system design. The feasibility program demonstrated that the airbag impact attenuation design will protect the lander upon impact with the Martian surface.

  19. Mars Pathfinder airbag impact attenuation system

    SciTech Connect

    Waye, D.E.; Cole, J.K. [Sandia National Labs., Albuquerque, NM (United States); Rivellini, T.P. [California Institute of Technology, Pasadena, CA (United States). Jet Propulsion Lab.

    1995-04-01

    The Mars Pathfinder spacecraft, scheduled for launch in November 1996, is designed to validate a low cost Entry, Descent, and Landing system and to perform scientific surface operations. The Jet Propulsion Laboratory and Sandia National Laboratories teamed to design, fabricate, test and validate a prototype 0.38 scale model of an airbag impact attenuation system. A computer code was developed to predict the performance of the airbag system. A test program in Sandia`s High Altitude Chamber was performed to validate the code and demonstrate the feasibility of the airbag concept and design. In addition, freefall tests were performed at representative velocities to demonstrate the structural integrity of the airbag system design. The feasibility program demonstrated that the airbag impact attenuation design will protect the lander upon impact with the Martian surface.

  20. APECS - The Atacama Pathfinder Experiment Control System

    E-print Network

    D. Muders; H. Hafok; F. Wyrowski; E. Polehampton; A. Belloche; C. Koenig; R. Schaaf; F. Schuller; J. Hatchell; F. v. d. Tak

    2006-05-04

    APECS is the distributed control system of the new Atacama Pathfinder EXperiment (APEX) telescope located on the Llano de Chajnantor at an altitude of 5107 m in the Atacama desert in northern Chile. APECS is based on Atacama Large Millimeter Array (ALMA) software and employs a modern, object-oriented design using the Common Object Request Broker Architecture (CORBA) as the middleware. New generic device interfaces simplify adding instruments to the control system. The Python based observer command scripting language allows using many existing software libraries and facilitates creating more complex observing modes. A new self-descriptive raw data format (Multi-Beam FITS or MBFITS) has been defined to store the multi-beam, multi-frequency data. APECS provides an online pipeline for initial calibration, observer feedback and a quick-look display. APECS is being used for regular science observations in local and remote mode since August 2005.

  1. Imager for Mars Pathfinder (IMP) image calibration

    USGS Publications Warehouse

    Reid, R.J.; Smith, P.H.; Lemmon, M.; Tanner, R.; Burkland, M.; Wegryn, E.; Weinberg, J.; Marcialis, R.; Britt, D.T.; Thomas, N.; Kramm, R.; Dummel, A.; Crowe, D.; Bos, B.J.; Bell, J.F., III; Rueffer, P.; Gliem, F.; Johnson, J.R.; Maki, J.N.; Herkenhoff, K.E.; Singer, Robert B.

    1999-01-01

    The Imager for Mars Pathfinder returned over 16,000 high-quality images from the surface of Mars. The camera was well-calibrated in the laboratory, with <5% radiometric uncertainty. The photometric properties of two radiometric targets were also measured with 3% uncertainty. Several data sets acquired during the cruise and on Mars confirm that the system operated nominally throughout the course of the mission. Image calibration algorithms were developed for landed operations to correct instrumental sources of noise and to calibrate images relative to observations of the radiometric targets. The uncertainties associated with these algorithms as well as current improvements to image calibration are discussed. Copyright 1999 by the American Geophysical Union.

  2. Bayesian Model Selection for LISA Pathfinder

    NASA Astrophysics Data System (ADS)

    Karnesis, N.; Nofrarias, M.; Sopuerta, C. F.; Gibert, F.; Lobo, A.

    2013-01-01

    The LISA Pathfinder mission (LPF) aims at validating the displacement and acceleration noise models and to test key technologies for the future LISA mission. The LISA Technology Package (LTP) Data Analysis team has developed complex models of the LTP for simulations and data analysis during the mission. These models contain a large number of parameters to be estimated and for that reason, we need to recover only the essential ones that describe the observations. Being able to distinguish between competing models that describe the data introduces many possible applications in LTP Data Analysis. In our analysis we use two main different approximations to compute the Bayes Factor: the Reversible Jump Markov Chain Monte Carlo (RJMCMC) and the Laplace approximations. They are applied first to toy models and then verified with full LTP models. This work is part of the LTPDA Matlab toolbox.

  3. Java PathFinder User Guide

    NASA Technical Reports Server (NTRS)

    Havelund, Klaus

    1999-01-01

    The JAVA PATHFINDER, JPF, is a translator from a subset of JAVA 1.0 to PROMELA, the programming language of the SPIN model checker. The purpose of JPF is to establish a framework for verification and debugging of JAVA programming based on model checking. The main goal is to automate program verification such that a programmer can apply it in the daily work without the need for a specialist to manually reformulate a program into a different notation in order to analyze the program. The system is especially suited for analyzing multi-threaded JAVA applications, where normal testing usually falls short. The system can find deadlocks and violations of boolean assertions stated by the programmer in a special assertion language. This document explains how to Use JPF.

  4. Postglacial fringing-reef to barrier-reef conversion on Tahiti links Darwin's reef types.

    PubMed

    Blanchon, Paul; Granados-Corea, Marian; Abbey, Elizabeth; Braga, Juan C; Braithwaite, Colin; Kennedy, David M; Spencer, Tom; Webster, Jody M; Woodroffe, Colin D

    2014-01-01

    In 1842 Charles Darwin claimed that vertical growth on a subsiding foundation caused fringing reefs to transform into barrier reefs then atolls. Yet historically no transition between reef types has been discovered and they are widely considered to develop independently from antecedent foundations during glacio-eustatic sea-level rise. Here we reconstruct reef development from cores recovered by IODP Expedition 310 to Tahiti, and show that a fringing reef retreated upslope during postglacial sea-level rise and transformed into a barrier reef when it encountered a Pleistocene reef-flat platform. The reef became stranded on the platform edge, creating a lagoon that isolated it from coastal sediment and facilitated a switch to a faster-growing coral assemblage dominated by acroporids. The switch increased the reef's accretion rate, allowing it to keep pace with rising sea level, and transform into a barrier reef. This retreat mechanism not only links Darwin's reef types, but explains the re-occupation of reefs during Pleistocene glacio-eustacy. PMID:24845540

  5. Topographic Map of Pathfinder Landing Site

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Topographic map of the landing site, to a distance of 60 meters from the lander in the LSC coordinate system. The lander is shown schematically in the center; 2.5 meter radius circle (black) centered on the camera was not mapped. Gentle relief [root mean square (rms) elevation variation 0.5 m; rms a directional slope 4O] and organization of topography into northwest and northeast-trending ridges about 20 meters apart are apparent. Roughly 30% of the illustrated area is hidden from the camera behind these ridges. Contours (0.2 m interval) and color coding of elevations were generated from a digital terrain model, which was interpolated by kriging from approximately 700 measured points. Angular and parallax point coordinates were measured manually on a large (5 m length) anaglyphic uncontrolled mosaic and used to calculate Cartesian (LSC) coordinates. Errors in azimuth on the order of 10 are therefore likely; elevation errors were minimized by referencing elevations to the local horizon. The uncertainty in range measurements increases quadratically with range. Given a measurement error of 1/2 pixel, the expected precision in range is 0.3 meter at 10 meter range, and 10 meters at 60 meter range. Repeated measurements were made, compared, and edited for consistency to improve the range precision. Systematic errors undoubtedly remain and will be corrected in future maps compiled digitally from geometrically controlled images. Cartographic processing by U.S. Geological Survey.

    NOTE: original caption as published in Science Magazine

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

  6. The magnetic properties experiments on Mars Pathfinder

    NASA Astrophysics Data System (ADS)

    Madsen, M. B.; Hviid, S. F.; Gunnlaugsson, H. P.; Knudsen, J. M.; Goetz, W.; Pedersen, C. T.; Dinesen, A. R.; Mogensen, C. T.; Olsen, M.; Hargraves, R. B.

    1999-04-01

    The Mars Pathfinder lander carried two magnet arrays, each containing five small permanent magnets of varying strength. The magnet arrays were passively exposed to the wind borne dust on Mars. By the end of the Mars Pathfinder mission a bull's-eye pattern was visible on the four strongest magnets of the arrays showing the presence of magnetic dust particles. From the images we conclude that the dust suspended in the atmosphere is not solely single phase particles of hematite (?-Fe2O3) and that single phase particles of the ferrimagnetic minerals maghemite (?-Fe2O3) or magnetite (Fe3O4) are not present as free particles in any appreciable amount. The material on the strongest magnets seems to be indistinguishable from the bright surface material around the lander. From X-ray fluorescence it is known that the soil consists mainly of silicates. The element iron constitutes about 13% of the soil. The particles in the airborne dust seem to be composite, containing a few percent of a strongly magnetic component. We conclude that the magnetic phase present in the airborne dust particles is most likely maghemite. The particles thus appear to consist of silicate aggregates stained or cemented by ferric oxides, some of the stain and cement being maghemite. These results imply that Fe2+ ions were leached from the bedrock, and after passing through a state as free Fe2+ ions in liquid water, the Fe2+ was oxidized to Fe3+ and then precipitated. It cannot, however, be ruled out that the magnetic particles are titanomagnetite (or titanomaghemite) occurring in palagonite, having been inherited directly from the bedrock.

  7. Exobiology site priorities for Mars Pathfinder

    NASA Technical Reports Server (NTRS)

    Farmer, Jack D.; Desmarais, David J.

    1994-01-01

    The fact that life developed on the Earth within the first billion years of its history makes it quite plausible that life may have also developed on Mars. If life did develop on Mars, it undoubtedly left behind a fossil record. Such a fossil record is likely to be more accessible than either subsurface environments that may harbor life, or scattered 'oases' that may be present at the surface. Consequently, the post-Viking approach of Mars exobiology has shifted focus to search for evidence of an ancient martian biosphere. This has led to the emergence of a new subdiscipline of paleontology, herein termed 'exopaleontology', which deals with the exploration for fossils on other planets and whose core concepts derive from Earth-based Precambrian paleontology, microbial ecology, and sedimentology. Potential targets on Mars for subaqueous spring deposits, sedimentary cements, and evaporites are ancient terminal lake basins where hydrological systems could have endured for some time under arid conditions. Potential targets for the Mars Pathfinder mission include channeled impact craters and areas of deranged drainage associated with outflows in northwest Arabia and Xanthe Terra, where water may have ponded temporarily to form lakes. The major uncertainty of such targets is their comparatively younger age and the potentially short duration of hydrological activity compared to older paleolake basins found in the southern hemisphere. However, it has been suggested that cycles of catastrophic flooding associated with Tharsis volcanism may have sustained a large body of water, Oceanus Borealis, in the northern plains area until quite late in martian history. Although problematic, the shoreline areas of the proposed northern ocean provide potential targets for a Mars Pathfinder mission aimed at exploring for carbonates or other potentially fossiliferous marine deposits. Carbonates and evaporites possess characteristic spectra signatures in the near-infrared and should be detectable using rover-based spectroscopy and other methods for in situ mineralogical analysis.

  8. Lithium-Thionyl Chloride Batteries for the Mars Pathfinder Microrover

    NASA Technical Reports Server (NTRS)

    Deligiannis, Frank; Frank, Harvey; Staniewicz, R. J.; Willson, John

    1996-01-01

    A discussion of the power requirements for the Mars Pathfinder Mission is given. Topics include: battery requirements; cell design; battery design; test descriptions and results. A summary of the results is also included.

  9. The Mars Pathfinder Outreach Project: A Rural Model

    NASA Astrophysics Data System (ADS)

    Larson, Shane L.; Larson, Michelle B.; Hiscock, William A.

    1998-04-01

    The Montana Mars Pathfinder Outreach Project (MPOP) has completed a successful year of interactive presentations with K-12 students across the west. Carefully selected Montana State University undergraduates visited over 4000 students in the year preceding the Pathfinder landing on Mars. Each presentation showcased a computer generated video of the Pathfinder launch and mission and a slide set about Mars along with engaging discussion between the students and the presenters. Teachers received a packet containing a mission fact sheet, a Pathfinder poster, pins, stickers and informational handouts. This high impact, low budget ($10,000) project proved very popular with students, teachers, principals and parents. In this talk we will discuss the organizational network, budget and time commitment needed to bring a project such as this to your area. Materials and monetary support for this project were provided by the Jet Propulsion Laboratory(JPL Contract #960543) and the Montana Space Grant Consortium.

  10. Launch Abort System Pathfinder Arrival - Duration: 108 seconds.

    NASA Video Gallery

    The Orion Launch Abort System, or LAS, pathfinder returned home to NASA Langley on Oct. 18 on its way to NASA's Kennedy Space Center. The hardware was built at Langley and was used in preparation f...

  11. Pathfinder aircraft taking off from ground - side view

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This 27-second video clip shows the Pathfinder taking off from Rogers Dry Lakebed near the NASA Dryden Flight Research Center on Edwards Air Force Base. Shown from the lakebed side, the video shows Edwards and Dryden in the background.

  12. Multi-wavelength surveys towards the SKA pathfinders

    E-print Network

    Matt J. Jarvis

    2008-01-30

    In these proceedings I discuss various extragalactic surveys which will be undertaken over the next few years and which will be complementary to any HI and/or continuum surveys with the SKA-pathfinder telescopes. I concentrate on the near-infrared public surveys which will be undertaken with the Visible and Infrared Survey Telscope for Astronomy (VISTA), and in particular the VISTA Deep Extragalactic Observations (VIDEO) survey which will provide the ideal data set to combine with any deep SKA-pathfinder observations of the extragalactic sky. After highlighting the links that the SKA pathfinders have with the various VISTA surveys, I briefly describe an approved large area survey to be carried out with the Herschel Space Observatory which has a large scientific overlap with the SKA pathfinder telescopes.

  13. Pathfinder aircraft taking off - setting new solar powered altitude record

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Pathfinder solar-powered remotely piloted aircraft climbs to a record-setting altitude of 50,567 feet during a flight Sept. 11, 1995, at NASA's Dryden Flight Research Center, Edwards, California. The flight was part of the NASA ERAST (Environmental Research Aircraft and Sensor Technology) program. The Pathfinder was designed and built by AeroVironment Inc., Monrovia, California. Solar arrays cover nearly all of the upper wing surface and produce electricity to power the aircraft's six motors. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

  14. Sewage impacts coral reefs at multiple levels of ecological organization.

    PubMed

    Reopanichkul, Pasinee; Schlacher, Thomas A; Carter, R W; Worachananant, Suchai

    2009-09-01

    Against a backdrop of rising sea temperatures and ocean acidification which pose global threats to coral reefs, excess nutrients and turbidity continue to be significant stressors at regional and local scales. Because interventions usually require local data on pollution impacts, we measured ecological responses to sewage discharges in Surin Marine Park, Thailand. Wastewater disposal significantly increased inorganic nutrients and turbidity levels, and this degradation in water quality resulted in substantial ecological shifts in the form of (i) increased macroalgal density and species richness, (ii) lower cover of hard corals, and (iii) significant declines in fish abundance. Thus, the effects of nutrient pollution and turbidity can cascade across several levels of ecological organization to change key properties of the benthos and fish on coral reefs. Maintenance or restoration of ecological reef health requires improved wastewater management and run-off control for reefs to deliver their valuable ecosystems services. PMID:19515390

  15. Coral reef resilience through biodiversity

    USGS Publications Warehouse

    Rogers, Caroline S.

    2013-01-01

    Irrefutable evidence of coral reef degradation worldwide and increasing pressure from rising seawater temperatures and ocean acidification associated with climate change have led to a focus on reef resilience and a call to “manage” coral reefs for resilience. Ideally, global action to reduce emission of carbon dioxide and other greenhouse gases will be accompanied by local action. Effective management requires reduction of local stressors, identification of the characteristics of resilient reefs, and design of marine protected area networks that include potentially resilient reefs. Future research is needed on how stressors interact, on how climate change will affect corals, fish, and other reef organisms as well as overall biodiversity, and on basic ecological processes such as connectivity. Not all reef species and reefs will respond similarly to local and global stressors. Because reef-building corals and other organisms have some potential to adapt to environmental changes, coral reefs will likely persist in spite of the unprecedented combination of stressors currently affecting them. The biodiversity of coral reefs is the basis for their remarkable beauty and for the benefits they provide to society. The extraordinary complexity of these ecosystems makes it both more difficult to predict their future and more likely they will have a future.

  16. Rapid survey protocol that provides dynamic information on reef condition to managers of the Great Barrier Reef.

    PubMed

    Beeden, R J; Turner, M A; Dryden, J; Merida, F; Goudkamp, K; Malone, C; Marshall, P A; Birtles, A; Maynard, J A

    2014-12-01

    Managing to support coral reef resilience as the climate changes requires strategic and responsive actions that reduce anthropogenic stress. Managers can only target and tailor these actions if they regularly receive information on system condition and impact severity. In large coral reef areas like the Great Barrier Reef Marine Park (GBRMP), acquiring condition and impact data with good spatial and temporal coverage requires using a large network of observers. Here, we describe the result of ~10 years of evolving and refining participatory monitoring programs used in the GBR that have rangers, tourism operators and members of the public as observers. Participants complete Reef Health and Impact Surveys (RHIS) using a protocol that meets coral reef managers' needs for up-to-date information on the following: benthic community composition, reef condition and impacts including coral diseases, damage, predation and the presence of rubbish. Training programs ensure that the information gathered is sufficiently precise to inform management decisions. Participants regularly report because the demands of the survey methodology have been matched to their time availability. Undertaking the RHIS protocol we describe involves three ~20 min surveys at each site. Participants enter data into an online data management system that can create reports for managers and participants within minutes of data being submitted. Since 2009, 211 participants have completed a total of more than 10,415 surveys at more than 625 different reefs. The two-way exchange of information between managers and participants increases the capacity to manage reefs adaptively, meets education and outreach objectives and can increase stewardship. The general approach used and the survey methodology are both sufficiently adaptable to be used in all reef regions. PMID:25179944

  17. Forecasting decadal changes in sea surface temperatures and coral bleaching within a Caribbean coral reef

    E-print Network

    Reidenbach, Matthew A.

    REPORT Forecasting decadal changes in sea surface temperatures and coral bleaching within affect the health of coral reefs by increasing rates of coral bleaching, how changes to atmospheric Á Coral reefs Á Sea surface temperature Á Coral bleaching Introduction A primary direct consequence

  18. Capitol Reef Petroglyphs

    USGS Multimedia Gallery

    From about 300-1300 CE, ancestors of the Hopi Tribe, Pueblo of Zuni, and Paiute Tribe lived in Capitol Reef. They are known by various names-archeologists call them the Fremont Culture; the Hopi Tribe calls them the Hisatsinom, or the

  19. Castle in Capitol Reef

    USGS Multimedia Gallery

    A view of the Castle, a prominent sandstone formation in Capitol Reef National Park. This area, known as the Fruita, is made up of three primary layers. The bottom sandstone layer is known as the Moenkopi Formation and is about 245 million years old. The middle gray-green layer is known as the Chinl...

  20. Capitol Reef's Castle

    USGS Multimedia Gallery

    A view of the Castle, a prominent sandstone formation in Capitol Reef National Park. This area, known as the Fruita, is made up of three primary layers. The bottom sandstone layer is known as the Moenkopi Formation and is about 245 million years old. The middle gray-green layer is known as the Chinl...

  1. Petroglyphs in Captiol Reef

    USGS Multimedia Gallery

    From about 300-1300 CE, ancestors of the Hopi Tribe, Pueblo of Zuni, and Paiute Tribe lived in Capitol Reef. They are known by various names-archeologists call them the Fremont Culture; the Hopi Tribe calls them the Hisatsinom, or the

  2. The Coral Reef Ecosystem

    NSDL National Science Digital Library

    2007-04-19

    Students examine a coral reef ecosystem to learn about its living and non-living parts and how they interact. They apply what they have learned to explore the world's biomes, including how the animals in each are adapted to their environment.

  3. Create a Coral Reef

    NSDL National Science Digital Library

    2012-06-26

    Educator Amy O'Donnell from the American Museum of Natural History guides learners to create a diorama of a coral reef. Learners will use craft skills to transform household materials into simulated brain coral, sea fans, sea anemones, and a sponge. This resource contains background information about coral and the use of dioramas in museums. Also includes extension ideas.

  4. Coral Reef Biological Criteria

    EPA Science Inventory

    Coral reefs worldwide are experiencing decline from a variety of stressors. Some important stressors are land-based sources of pollution and human activities in the coastal zone. However, few tools are available to offset the impact of these stressors. The Clean Water Act (CWA...

  5. CORAL REEF BIOCRITERIA

    EPA Science Inventory

    Coral reefs worldwide are experiencing the greatest decline of their known existence and few tools are available to offset the growing impacts of human coastal and watershed activities. Biocriteria are a potentially effective means to evaluate and restore impaired waters, but are...

  6. Selection of the Mars Pathfinder Landing Site

    NASA Technical Reports Server (NTRS)

    Golombek, M. P.; Cook, R. A.; Moore, H. J.; Parker, T. J.

    1997-01-01

    The Mars Pathfinder spacecraft will land on a depositional fan near the mouth of the catastrophic outflow channel, Ares Vallis (19.5 deg N, 32.8 deg W). This site offers the prospect of analyzing a variety of rock types from the ancient cratered highlands, intermediate-age ridged plains, and reworked channel deposits. Analyses of these rocks by Pathfinder instruments will enable first-order scientific questions to be addressed, such as differentiation of the crust, the development of weathering products, and the nature of the early environment, as well as their subsequent evolution on Mars. Constraints imposed by: (1) spacecraft and rover designs (which are robust), (2) entry, descent, and landing, (3) scientific potential at various sites, and (4) safety were important considerations in site selection. Engineering constraints require a 70 km by 200 km smooth, flat (low slopes) area located between 10 deg and 20 deg N that is below 0 km elevation, with average radar reflectivity, little dust, and moderate rock abundance. Three regions on Mars are between 10 deg and 20 deg N and below 0 km elevation: Chryse, Amazonis, and Isidis-Elysitun. Science considerations favor sites at the mouths of outflow channels (grab bag sites offer an assay of rock types on Mars), highland sites (early crustal differentiation and climate), and sites covered with dark (unoxidized) material. Sites are considered safe if they are clearly below 0 km elevation, appear acceptably free of hazards in high-resolution (less than 50 m/pixel) Viking orbiter images and have acceptable reflectivity and roughness at radar wavelengths, thermal inertia, rock abundance, red to violet ratio, and albedo. Recent 3.5-cm wavelength radar observations were used to verify elevation, reflectivity, and roughness within the landing ellipses. Three sites meet all of these criteria: Ares Vallis, Tritonis Lacus, and Isidis. Although Isidis appears to be safer than Tritonis and Ares, the greater scientific potential at Ares Vallis resulted in its selection. Comparisons of the Grand Coulee (channel) and the depositional Ephrata Fan of the Channeled Scabland in eastern Washington, with Ar-es Vallis and its depositional fan also suggest the Ares Vallis landing site is safe and scientifically interesting.

  7. Coral Reef Protection: A Watershed Approach

    NSDL National Science Digital Library

    EPA's home page on coral reef protection activities, including The International Coral Reef Initiative, and The Coral Reef Symposium. A tremendous resource for educators interested in coral reef basics through advanced topics such as coral reef ecology and legislation. Site includes peer-reviewed journal articles, factsheets, maps, and video. The Links section is packed with extensive coral reef information sites covering international and domestic initiatives, research, and even a section for kids and teachers.

  8. An observational heat budget analysis of a coral reef, Heron Reef, Great Barrier Reef, Australia

    NASA Astrophysics Data System (ADS)

    MacKellar, Mellissa C.; McGowan, Hamish A.; Phinn, Stuart R.

    2013-03-01

    Measurements of the surface energy balance, the structure and evolution of the convective atmospheric reef layer (CARL), and local meteorology and hydrodynamics were made during June 2009 and February 2010 at Heron Reef, Australia, to establish the relative partitioning of heating within the water and atmosphere. Horizontal advection was shown to moderate temperature in the CARL and the water, having a cooling influence on the atmosphere, and providing an additional source or sink of energy to the water overlying the reef, depending on tide. The key driver of atmospheric heating was surface sensible heat flux, while heating of the reef water was primarily due to solar radiation, and thermal conduction and convection from the reef substrate. Heating and cooling processes were more defined during winter due to higher sensible and latent heat fluxes and strong diurnal evolution of the CARL. Sudden increases in water temperature were associated with inundation of warmer oceanic water during the flood tide, particularly in winter due to enhanced nocturnal cooling of water overlying the reef. Similarly, cooling of the water over the reef occurred during the ebb tide as heat was transported off the reef to the surrounding ocean. While these results are the first to shed light on the heat budget of a coral reef and overlying CARL, longer-term, systematic measurements of reef thermal budgets are needed under a range of meteorological and hydrodynamic conditions, and across various reef types to elucidate the influence on larger-scale oceanic and atmospheric processes. This is essential for understanding the role of coral reefs in tropical and sub-tropical meteorology; the physical processes that take place during coral bleaching events, and coral and algal community dynamics on coral reefs.

  9. USGS Pacific Coral Reefs Website

    NSDL National Science Digital Library

    This gateway provides access to United States Geological Survey (USGS) studies of coral reefs in the Pacific Ocean, especially in the Hawaiian Islands where efforts are are focused on mapping, monitoring, remote sensing, sediment transport studies, and collection of tide, wave, and current data from remote stations. Materials include basic facts about coral reefs, an overview of the risks and threats to reefs, news items, and links to publications and other related organizations. Separate pages describe the individual projects, including mapping of the reefs, efforts to monitor changes on the reefs (the Coral Reef Assessment and Monitoring Program (CRAMP)), and studies of sedimentation and sediment transport. There is also an interactive map showing the locations of the study areas.

  10. Oceanic forcing of coral reefs.

    PubMed

    Lowe, Ryan J; Falter, James L

    2015-01-01

    Although the oceans play a fundamental role in shaping the distribution and function of coral reefs worldwide, a modern understanding of the complex interactions between ocean and reef processes is still only emerging. These dynamics are especially challenging owing to both the broad range of spatial scales (less than a meter to hundreds of kilometers) and the complex physical and biological feedbacks involved. Here, we review recent advances in our understanding of these processes, ranging from the small-scale mechanics of flow around coral communities and their influence on nutrient exchange to larger, reef-scale patterns of wave- and tide-driven circulation and their effects on reef water quality and perceived rates of metabolism. We also examine regional-scale drivers of reefs such as coastal upwelling, internal waves, and extreme disturbances such as cyclones. Our goal is to show how a wide range of ocean-driven processes ultimately shape the growth and metabolism of coral reefs. PMID:25251270

  11. Evaluation of reef shell embankment

    NASA Astrophysics Data System (ADS)

    Melancon, J. L.; Bokun, S. G.

    1980-12-01

    A method of constructing an embankment over marshland soils by end-dumping reef shell directly onto the marshland with no other major subgrade preparation is discussed. The dumped reef shell is then spread out to form a 'floating' embankment over the soft marshland. The subsidence characteristics of a reef shell embankment are compared with those of a clam shell embankment to determine if such a reef shell embankment would provide adequate structural support for traffic. Results show it is physically and economically feasible to construct a reef shell embankment on soft organic marshland soils. A properly constructed reef shell embankment develops into a homogeneous floating slab of substantial stability and strength capable of supporting allowable traffic loads.

  12. Data Analysis for the LISA Pathfinder Mission

    NASA Technical Reports Server (NTRS)

    Thorpe, James Ira

    2009-01-01

    The LTP (LISA Technology Package) is the core part of the Laser Interferometer Space Antenna (LISA) Pathfinder mission. The main goal of the mission is to study the sources of any disturbances that perturb the motion of the freely-falling test masses from their geodesic trajectories as well as 10 test various technologies needed for LISA. The LTP experiment is designed as a sequence of experimental runs in which the performance of the instrument is studied and characterized under different operating conditions. In order to best optimize subsequent experimental runs, each run must be promptly analysed to ensure that the following ones make best use of the available knowledge of the instrument ' In order to do this, all analyses must be designed and tested in advance of the mission and have sufficient built-in flexibility to account for unexpected results or behaviour. To support this activity, a robust and flexible data analysis software package is also required. This poster presents two of the main components that make up the data analysis effort: the data analysis software and the mock-data challenges used to validate analysis procedures and experiment designs.

  13. Bayesian model selection for LISA pathfinder

    NASA Astrophysics Data System (ADS)

    Karnesis, Nikolaos; Nofrarias, Miquel; Sopuerta, Carlos F.; Gibert, Ferran; Armano, Michele; Audley, Heather; Congedo, Giuseppe; Diepholz, Ingo; Ferraioli, Luigi; Hewitson, Martin; Hueller, Mauro; Korsakova, Natalia; McNamara, Paul W.; Plagnol, Eric; Vitale, Stefano

    2014-03-01

    The main goal of the LISA Pathfinder (LPF) mission is to fully characterize the acceleration noise models and to test key technologies for future space-based gravitational-wave observatories similar to the eLISA concept. The data analysis team has developed complex three-dimensional models of the LISA Technology Package (LTP) experiment onboard the LPF. These models are used for simulations, but, more importantly, they will be used for parameter estimation purposes during flight operations. One of the tasks of the data analysis team is to identify the physical effects that contribute significantly to the properties of the instrument noise. A way of approaching this problem is to recover the essential parameters of a LTP model fitting the data. Thus, we want to define the simplest model that efficiently explains the observations. To do so, adopting a Bayesian framework, one has to estimate the so-called Bayes factor between two competing models. In our analysis, we use three main different methods to estimate it: the reversible jump Markov chain Monte Carlo method, the Schwarz criterion, and the Laplace approximation. They are applied to simulated LPF experiments in which the most probable LTP model that explains the observations is recovered. The same type of analysis presented in this paper is expected to be followed during flight operations. Moreover, the correlation of the output of the aforementioned methods with the design of the experiment is explored.

  14. Coral Reefs in Hot Water

    NSDL National Science Digital Library

    2012-08-03

    In this activity, student teams identify the locations of coral reefs around the world, examine infrared satellite images of the Earth, and research the impacts that are threatening the survival of coral reefs. Each team creates a short oral presentation describing the coral reef they have researched. Students then plot on a composite map the locations where coral bleaching is occurring. Student worksheets, a teacher guide, and assessment rubric are included. This activity is part of Coastal Areas: Coral Reefs in Hot Water, part of the lesson series, The Potential Consequences of Climate Variability and Change.

  15. Millenium Coral Reefs Landsat Archive

    NSDL National Science Digital Library

    Users can access remote imagery of coral reefs by clicking on an interactive world map. The imagery consists of tiled mosaics which can be zoomed, panned, and downloaded. This archive of coral reef images is part of a project whose purpose is to develop global reef maps as a base for future research. It was created in a partnership with NASA, international agencies, universities and other organizations to provide natural resource managers a comprehensive world data resource on coral reefs and adjacent land areas.

  16. Digital Reef Rugosity Estimates Coral Reef Habitat Complexity

    PubMed Central

    Dustan, Phillip; Doherty, Orla; Pardede, Shinta

    2013-01-01

    Ecological habitats with greater structural complexity contain more species due to increased niche diversity. This is especially apparent on coral reefs where individual coral colonies aggregate to give a reef its morphology, species zonation, and three dimensionality. Structural complexity is classically measured with a reef rugosity index, which is the ratio of a straight line transect to the distance a flexible chain of equal length travels when draped over the reef substrate; yet, other techniques from visual categories to remote sensing have been used to characterize structural complexity at scales from microhabitats to reefscapes. Reef-scale methods either lack quantitative precision or are too time consuming to be routinely practical, while remotely sensed indices are mismatched to the finer scale morphology of coral colonies and reef habitats. In this communication a new digital technique, Digital Reef Rugosity (DRR) is described which utilizes a self-contained water level gauge enabling a diver to quickly and accurately characterize rugosity with non-invasive millimeter scale measurements of coral reef surface height at decimeter intervals along meter scale transects. The precise measurements require very little post-processing and are easily imported into a spreadsheet for statistical analyses and modeling. To assess its applicability we investigated the relationship between DRR and fish community structure at four coral reef sites on Menjangan Island off the northwest corner of Bali, Indonesia and one on mainland Bali to the west of Menjangan Island; our findings show a positive relationship between DRR and fish diversity. Since structural complexity drives key ecological processes on coral reefs, we consider that DRR may become a useful quantitative community-level descriptor to characterize reef complexity. PMID:23437380

  17. Coral Reefs on the Edge? Carbon Chemistry on Inshore Reefs of the Great Barrier Reef

    PubMed Central

    Uthicke, Sven; Furnas, Miles; Lønborg, Christian

    2014-01-01

    While increasing atmospheric carbon dioxide (CO2) concentration alters global water chemistry (Ocean Acidification; OA), the degree of changes vary on local and regional spatial scales. Inshore fringing coral reefs of the Great Barrier Reef (GBR) are subjected to a variety of local pressures, and some sites may already be marginal habitats for corals. The spatial and temporal variation in directly measured parameters: Total Alkalinity (TA) and dissolved inorganic carbon (DIC) concentration, and derived parameters: partial pressure of CO2 (pCO2); pH and aragonite saturation state (?ar) were measured at 14 inshore reefs over a two year period in the GBR region. Total Alkalinity varied between 2069 and 2364 µmol kg?1 and DIC concentrations ranged from 1846 to 2099 µmol kg?1. This resulted in pCO2 concentrations from 340 to 554 µatm, with higher values during the wet seasons and pCO2 on inshore reefs distinctly above atmospheric values. However, due to temperature effects, ?ar was not further reduced in the wet season. Aragonite saturation on inshore reefs was consistently lower and pCO2 higher than on GBR reefs further offshore. Thermodynamic effects contribute to this, and anthropogenic runoff may also contribute by altering productivity (P), respiration (R) and P/R ratios. Compared to surveys 18 and 30 years ago, pCO2 on GBR mid- and outer-shelf reefs has risen at the same rate as atmospheric values (?1.7 µatm yr?1) over 30 years. By contrast, values on inshore reefs have increased at 2.5 to 3 times higher rates. Thus, pCO2 levels on inshore reefs have disproportionately increased compared to atmospheric levels. Our study suggests that inshore GBR reefs are more vulnerable to OA and have less buffering capacity compared to offshore reefs. This may be caused by anthropogenically induced trophic changes in the water column and benthos of inshore reefs subjected to land runoff. PMID:25295864

  18. Mars Pathfinder Rover-Lewis Research Center Technology Experiments Program

    NASA Technical Reports Server (NTRS)

    Stevenson, Steven M.

    1997-01-01

    An overview of NASA's Mars Pathfinder Program is given and the development and role of three technology experiments from NASA's Lewis Research Center and carried on the Mars Pathfinder rover is described. Two recent missions to Mars were developed and managed by the Jet Propulsion Laboratory, and launched late last year: Mars Global Surveyor in November 1996 and Mars Pathfinder in December 1996. Mars Global Surveyor is an orbiter which will survey the planet with a number of different instruments, and will arrive in September 1997, and Mars Pathfinder which consists of a lander and a small rover, landing on Mars July 4, 1997. These are the first two missions of the Mars Exploration Program consisting of a ten year series of small robotic martian probes to be launched every 26 months. The Pathfinder rover will perform a number of technology and operational experiments which will provide the engineering information necessary to design and operate more complex, scientifically oriented surface missions involving roving vehicles and other machinery operating in the martian environment. Because of its expertise in space power systems and technologies, space mechanisms and tribology, Lewis Research Center was asked by the Jet Propulsion Laboratory, which is heading the Mars Pathfinder Program, to contribute three experiments concerning the effects of the martian environment on surface solar power systems and the abrasive qualities of the Mars surface material. In addition, rover static charging was investigated and a static discharge system of several fine Tungsten points was developed and fixed to the rover. These experiments and current findings are described herein.

  19. Using coral disease prevalence to assess the effects of concentrating tourism activities on offshore reefs in a tropical marine park.

    PubMed

    Lamb, Joleah B; Willis, Bette L

    2011-10-01

    Concentrating tourism activities can be an effective way to closely manage high-use parks and minimize the extent of the effects of visitors on plants and animals, although considerable investment in permanent tourism facilities may be required. On coral reefs, a variety of human-related disturbances have been associated with elevated levels of coral disease, but the effects of reef-based tourist facilities (e.g., permanent offshore visitor platforms) on coral health have not been assessed. In partnership with reef managers and the tourism industry, we tested the effectiveness of concentrating tourism activities as a strategy for managing tourism on coral reefs. We compared prevalence of brown band disease, white syndromes, black band disease, skeletal eroding band, and growth anomalies among reefs with and without permanent tourism platforms within the Great Barrier Reef Marine Park. Coral diseases were 15 times more prevalent at reefs with offshore tourism platforms than at nearby reefs without platforms. The maximum prevalence and maximum number of cases of each disease type were recorded at reefs with permanently moored tourism platforms. Diseases affected 10 coral genera from 7 families at reefs with platforms and 4 coral genera from 3 families at reefs without platforms. The greatest number of disease cases occurred within the spatially dominant acroporid corals, which exhibited 18-fold greater disease prevalence at reefs with platforms than at reefs without platforms. Neither the percent cover of acroporids nor overall coral cover differed significantly between reefs with and without platforms, which suggests that neither factor was responsible for the elevated levels of disease. Identifying how tourism activities and platforms facilitate coral disease in marine parks will help ensure ongoing conservation of coral assemblages and tourism. PMID:21848962

  20. PATHFINDER: Probing Atmospheric Flows in an Integrated and Distributed Environment

    NASA Technical Reports Server (NTRS)

    Wilhelmson, R. B.; Wojtowicz, D. P.; Shaw, C.; Hagedorn, J.; Koch, S.

    1995-01-01

    PATHFINDER is a software effort to create a flexible, modular, collaborative, and distributed environment for studying atmospheric, astrophysical, and other fluid flows in the evolving networked metacomputer environment of the 1990s. It uses existing software, such as HDF (Hierarchical Data Format), DTM (Data Transfer Mechanism), GEMPAK (General Meteorological Package), AVS, SGI Explorer, and Inventor to provide the researcher with the ability to harness the latest in desktop to teraflop computing. Software modules developed during the project are available in the public domain via anonymous FTP from the National Center for Supercomputing Applications (NCSA). The address is ftp.ncsa.uiuc.edu, and the directory is /SGI/PATHFINDER.

  1. Sandstone Cliffs in Capitol Reef

    USGS Multimedia Gallery

    Sandstone cliffs in Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  2. Sandstone Cliff in Capitol Reef

    USGS Multimedia Gallery

    A sandstone cliff in Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  3. Sandstone Monolith in Capitol Reef

    USGS Multimedia Gallery

    A sandstone monolith in Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  4. Perspectives in coral reef hydrodynamics

    NASA Astrophysics Data System (ADS)

    Hearn, Clifford J.

    2011-06-01

    Some developments in coral reef hydrodynamics over the last decade are reviewed with an overview of papers in this special issue. Advances in hydrodynamics based on improved understanding of topographic complexity are illustrated for the reef at Kilo Nalu Observatory and Kaneohe Bay (both in Hawaii). Models of the roughness layer are discussed as a background to numerical models of reef hydrodynamics for Molokai and Guam. Topographic complexity produces spatial temperature variability over reefs creating thermal microclimates which are reported in this issue for the Red Sea. Uptake of ocean nutrients by reefs is controlled by hydrodynamics, and papers in this issue show its critical role in the ecology of a fringing reef at La Réunion Island; nutrient uptake rates are discussed here using new data for Hearn Roughness and Decadal Rugosity. The role of upwelled water by large amplitude internal waves on reefs is reported for the Similan Islands, providing major new evidence for the role of hydrodynamics in the ecology of reefs and its importance to climate change. The review suggests some important areas for new research including simulated corals used in flumes and the field. Major new modeling based on measured roughness maps combined with small scale lattice Boltzmann simulations should be possible in the next decade.

  5. Keeping Watch on Coral Reefs

    NSDL National Science Digital Library

    NOAA Ocean Service Education

    This activity identifies and explains the benefits of and threats to coral reef systems. Students read tutorials, describe the role of satellites, analyze oceanographic data and identify actions that can be undertaken to reduce or eliminate threats to coral reefs. As a culminating activity, students prepare a public education program.

  6. Coral reefs and carbon dioxide

    SciTech Connect

    Buddemeier, R.W. [Kansas Geological Survey, Lawrence, KS (United States)

    1996-03-01

    This commentary argues the conclusion from a previous article, which investigates diurnal changes in carbon dioxide partial pressure and community metabolism on coral reefs, that coral `reefs might serve as a sink, not a source, for atmospheric carbon dioxide.` Commentaries from two groups are given along with the response by the original authors, Kayanne et al. 27 refs.

  7. Functional versatility supports coral reef biodiversity

    E-print Network

    Wainwright, Peter C.

    Functional versatility supports coral reef biodiversity D. R. Bellwood1,*, P. C. Wainwright2 , C. J. Fulton1 and A. S. Hoey1 1 Department of Marine Biology, Centre for Coral Reef Biodiversity, James Cook of high biodiversity on coral reefs. Keywords: coral reef fishes; specialist; generalist; functional

  8. The CLOUDSAT Experiment: A NASA Pathfinder Mission

    NASA Astrophysics Data System (ADS)

    Stephens, G.; Vane, D.

    2003-04-01

    CloudSat will be the first spaceborne deployment of a 94-GHz cloud profiling radar. The mission is a partnership between NASA, Colorado State University, the Canadian Space Agency (CSA), the US Air Force (USAF), and the US Department of Energy's Atmospheric Radiation Measurements (ARM) Program. The spacecraft will be launched in 2004 and will fly in on-orbit formation with the CALIPSO spacecraft and the EOS-Aqua spacecraft, providing a suite of measurements for cloud and aerosol studies. The CloudSat experiment promotes the optimal use of multi-sensor data to produce new pathfinding knowledge that will advance our understanding of the participation of clouds and the hydrological cycle in the Earth climate system. The vertical profile of cloud properties provided by CloudSat fills a critical gap in the investigation of feedback mechanisms linking clouds to climate. Measuring the vertical profile of cloud properties is best addressed by a combination of active and passive instruments, and this will be achieved by combining the radar data of CloudSat with active and passive data from other sensors of the constellation. CloudSat will also provide the first real estimate of the mass of water and ice in the atmosphere and the proportion of this water and ice that falls as precipitation. The CloudSat Science Team is an international partnership, with members from USA, Canada, Japan and Europe having expertise in cloud radar design and observations, cloud and radiation research, and NWP, GCM and cloud modeling. Validation will rely heavily on the systematic measurement programs of ARM as well as systematic measurements planned for selected sites in Europe and Japan. Validation will also benefit from the aircraft radar measurement activities of USA, Canada, Japan and Europe, from the measurement capabilities at number of universities, and from cloud field-campaign activities representing targets of opportunity planned in the coming years, including field campaigns associated with the CALIPSO and AQUA missions. Further information on the CloudSat mission may be obtained from the author or by accessing the CloudSat Home Page at http://cloudsat.atmos.colostate.edu.

  9. Self-generated morphology in lagoon reefs

    PubMed Central

    Hamblin, Michael G.

    2015-01-01

    The three-dimensional form of a coral reef develops through interactions and feedbacks between its constituent organisms and their environment. Reef morphology therefore contains a potential wealth of ecological information, accessible if the relationships between morphology and ecology can be decoded. Traditionally, reef morphology has been attributed to external controls such as substrate topography or hydrodynamic influences. Little is known about inherent reef morphology in the absence of external control. Here we use reef growth simulations, based on observations in the cellular reefs of Western Australia’s Houtman Abrolhos Islands, to show that reef morphology is fundamentally determined by the mechanical behaviour of the reef-building organisms themselves—specifically their tendency to either remain in place or to collapse. Reef-building organisms that tend to remain in place, such as massive and encrusting corals or coralline algae, produce nodular reefs, whereas those that tend to collapse, such as branching Acropora, produce cellular reefs. The purest reef growth forms arise in sheltered lagoons dominated by a single type of reef builder, as in the branching Acropora-dominated lagoons of the Abrolhos. In these situations reef morphology can be considered a phenotype of the predominant reef building organism. The capacity to infer coral type from reef morphology can potentially be used to identify and map specific coral habitat in remotely sensed images. More generally, identifying ecological mechanisms underlying other examples of self-generated reef morphology can potentially improve our understanding of present-day reef ecology, because any ecological process capable of shaping a reef will almost invariably be an important process in real time on the living reef. PMID:26175962

  10. Self-generated morphology in lagoon reefs.

    PubMed

    Blakeway, David; Hamblin, Michael G

    2015-01-01

    The three-dimensional form of a coral reef develops through interactions and feedbacks between its constituent organisms and their environment. Reef morphology therefore contains a potential wealth of ecological information, accessible if the relationships between morphology and ecology can be decoded. Traditionally, reef morphology has been attributed to external controls such as substrate topography or hydrodynamic influences. Little is known about inherent reef morphology in the absence of external control. Here we use reef growth simulations, based on observations in the cellular reefs of Western Australia's Houtman Abrolhos Islands, to show that reef morphology is fundamentally determined by the mechanical behaviour of the reef-building organisms themselves-specifically their tendency to either remain in place or to collapse. Reef-building organisms that tend to remain in place, such as massive and encrusting corals or coralline algae, produce nodular reefs, whereas those that tend to collapse, such as branching Acropora, produce cellular reefs. The purest reef growth forms arise in sheltered lagoons dominated by a single type of reef builder, as in the branching Acropora-dominated lagoons of the Abrolhos. In these situations reef morphology can be considered a phenotype of the predominant reef building organism. The capacity to infer coral type from reef morphology can potentially be used to identify and map specific coral habitat in remotely sensed images. More generally, identifying ecological mechanisms underlying other examples of self-generated reef morphology can potentially improve our understanding of present-day reef ecology, because any ecological process capable of shaping a reef will almost invariably be an important process in real time on the living reef. PMID:26175962

  11. The International Coral Reef Information Network

    NSDL National Science Digital Library

    International Coral Reef Action Network (ICRAN)

    This extensive site was originally created to support coral reef conservation by the International Coral Reef Initiative (ICRI). The site serves to provide general coral reef information, tools and resources, and a central coral reef communications and network hub. The site also provides a library which houses descriptions of brochures, books, videos and other items suitable for coral reef awareness and education efforts. Some publications are available for download directly from this site, while others are available for purchase.

  12. General geology and geomorphology of the Mars Pathfinder landing site

    Microsoft Academic Search

    A. W. Ward; L. R. Gaddis; R. L. Kirk; L. A. Soderblom; K. L. Tanaka; M. P. Golombek; T. J. Parker; R. Greeley; R. O. Kuzmin

    1999-01-01

    The Mars Pathfinder spacecraft landed on relatively young (late Hesperian - early Amazonian; 3.1-0.7 Ga) plains in Chryse Planitia near the mouth of Ares Vallis. Images returned from the spacecraft reveal a complex landscape of ridges and troughs, large hills and crater rims, rocks and boulders of various sizes and shapes, and surficial deposits, indicating a complex, multistage history of

  13. Aeolian features and processes at the Mars Pathfinder landing site

    Microsoft Academic Search

    Ronald Greeley; Michael Kraft; Robert Sullivan; Gregory Wilson; Nathan Bridges; Ken Herkenhoff; Ruslan O. Kuzmin; Michael Malin; Wes Ward

    1999-01-01

    The Mars Pathfinder landing site contains abundant features attributed to aeolian, or wind, processes. These include wind tails, drift deposits, duneforms of various types, ripplelike features, and ventifacts (the first clearly seen on Mars). Many of these features are consistent with formation involving sand-size particles. Although some features, such as dunes, could develop from saltating sand-size aggregates of finer grains,

  14. Pathfinding in Open Terrain S. D. Goodwin, S. Menon

    E-print Network

    Pratt, Vaughan

    representation (e.g., grids, waypoints, navigation meshes, etc.), changing the heuristic (e.g., Manhattan geometrical solution. We provide some preliminary indication of the potential merit of the approach. 1. Many approaches to the pathfinding problem model the underlying world as a grid. The squares

  15. Pathfinder wing tip video at 50,000 feet

    NASA Technical Reports Server (NTRS)

    1995-01-01

    In this clip, the Pathfinder's wing camera shows the view from 50,000 feet. Below is the reddish-brown desert, with the curvature of the Earth visible. Above this is a haze, which blends into the blue-black sky. The vehicle is more than 10,000 feet above an airliner's normal altitude.

  16. LISA Pathfinder: the geodesy explorer testing alternative theories of gravity

    NASA Astrophysics Data System (ADS)

    Armano, Michele

    The LISA Pathfinder spacecraft by ESA is on schedule to fly by autumn 2015. Implementing a high precision free-fall in-flight system near a Lagrangian point, the mission relies on technologies never used before in space environments and crucial to gravitational waves observatories. The core instrument configuration makes LISA Pathfinder a gradiometer of unprecedented sensitivity. The designated orbit places it in position to further cruise through a volume of space where Newtonian pulls compensate and the Newtonian acceleration is close to zero. In the global picture that sees several dark matter/energy models and many theories at work to match observations, the free-fall specialist LISA Pathfinder can directly explore gravity at its alleged depart from the Newtonian regime, realizing a null dynamical test so far missing between astrophysical measurements and planetary tests. We will explicitly consider MOND theories as a test canvas and show that without further modifications the LISA Pathfinder instrument could sample several scales of the Newtonian-MONDian regime. We shall highlight the science case, the current experiment, the measurement design and the related data analysis.

  17. Pathfinder Meets DB2 Relational XQuery Optimization Techniques

    E-print Network

    Grust, Torsten

    to provide information about its node hierarchy, (2) the use of generated columns and materialized query's dynamic semantics, to deploy RDBMSs as efficient and scalable XQuery proces- sors. For the XQuery dialect [$v as] t return e2...default return en Table 1: Excerpt of XQuery dialect supported by Pathfinder (s

  18. Solar array model corrections from Mars Pathfinder Lander data

    Microsoft Academic Search

    R. C. Ewell; D. R. Burger

    1997-01-01

    The MESUR solar array power model for the Mars Pathfinder spacecraft initially assumed values for input variables. After landing, early surface variables such as array tilt and azimuth or early environmental variables such as array temperature can be corrected. Correction of later environmental variables such as tau versus time, spectral shift, dust deposition and UV darkening is dependent upon time,

  19. Mars Suface Layer Climatology from Viking and Pathfinder

    Microsoft Academic Search

    S. E. Larsen; H. E. Jørgensen; J. Murphy; J. E. Tillman; J. T. Schoffield

    2003-01-01

    The study of mean flow and turbulence of the atmospheric surface boundary layer on Mars have been based on in-situ wind and temperature data from the Viking and Pathfinder missions. Largely the behaviour of surface layer turbulence and mean flow on Mars is found to obey the same scaling laws as on Earth. The largest micrometeorological differences between the two

  20. Results of the Imager for Mars Pathfinder windsock experiment

    USGS Publications Warehouse

    Sullivan, R.; Greeley, R.; Kraft, M.; Wilson, G.; Golombek, M.; Herkenhoff, K.; Murphy, J.; Smith, P.

    2000-01-01

    The Imager for Mars Pathfinder (IMP) windsock experiment measured wind speeds at three heights within 1.2 m of the Martian surface during Pathfinder landed operations. These wind data allowed direct measurement of near-surface wind profiles on Mars for the first time, including determination of aerodynamic roughness length and wind friction speeds. Winds were light during periods of windsock imaging, but data from the strongest breezes indicate aerodynamic roughness length of 3 cm at the landing site, with wind friction speeds reaching 1 m/s. Maximum wind friction speeds were about half of the threshold-of-motion friction speeds predicted for loose, fine-grained materials on smooth Martian terrain and about one third of the threshold-of-motion friction speeds predicted for the same size particles over terrain with aerodynamic roughness of 3 cm. Consistent with this, and suggesting that low wind speeds prevailed when the windsock array was not imaged and/or no particles were available for aeolian transport, no wind-related changes to the surface during mission operations have been recognized. The aerodynamic roughness length reported here implies that proposed deflation of fine particles around the landing site, or activation of duneforms seen by IMP and Sojourner, would require wind speeds >28 m/s at the Pathfinder top windsock height (or >31 m/s at the equivalent Viking wind sensor height of 1.6 m) and wind speeds >45 m/s above 10 m. These wind speeds would cause rock abrasion if a supply of durable particles were available for saltation. Previous analyses indicate that the Pathfinder landing site probably is rockier and rougher than many other plains units on Mars, so aerodynamic roughness length elsewhere probably is less than the 3-cm value reported for the Pathfinder site. Copyright 2000 by the American Geophysical Union.

  1. Widespread Reduction in Coral Growth Rates on the Mesoamerican Reef Following the 1998 El Nino and Hurricane Mitch

    Microsoft Academic Search

    J. E. Carilli; R. D. Norris; K. A. Hughen

    2006-01-01

    Corals on the Mesoamerican Reef have been declining in health over the past few decades, and it is important to determine the cause, if conservation measures are to be effective. Cores from large Montastrea spp., Diploria strigosa, and Siderastrea siderea corals were collected in two locations on the Belizean barrier reef: 34 from Frank's Caye, Sapodilla Cayes, in the southern

  2. Effectiveness of benthic foraminiferal and coral assemblages as water quality indicators on inshore reefs of the Great Barrier Reef, Australia

    NASA Astrophysics Data System (ADS)

    Uthicke, S.; Thompson, A.; Schaffelke, B.

    2010-03-01

    Although the debate about coral reef decline focuses on global disturbances (e.g., increasing temperatures and acidification), local stressors (nutrient runoff and overfishing) continue to affect reef health and resilience. The effectiveness of foraminiferal and hard-coral assemblages as indicators of changes in water quality was assessed on 27 inshore reefs along the Great Barrier Reef. Environmental variables (i.e., several water quality and sediment parameters) and the composition of both benthic foraminiferal and hard-coral assemblages differed significantly between four regions (Whitsunday, Burdekin, Fitzroy, and the Wet Tropics). Grain size and organic carbon and nitrogen content of sediments, and a composite water column parameter (based on turbidity and concentrations of particulate matter) explained a significant amount of variation in the data (tested by redundancy analyses) in both assemblages. Heterotrophic species of foraminifera were dominant in sediments with high organic content and in localities with low light availability, whereas symbiont-bearing mixotrophic species were dominant elsewhere. A similar suite of parameters explained 89% of the variation in the FORAM index (a Caribbean coral reef health indicator) and 61% in foraminiferal species richness. Coral richness was not related to environmental setting. Coral assemblages varied in response to environmental variables, but were strongly shaped by acute disturbances (e.g., cyclones, Acanthaster planci outbreaks, and bleaching), thus different coral assemblages may be found at sites with the same environmental conditions. Disturbances also affect foraminiferal assemblages, but they appeared to recover more rapidly than corals. Foraminiferal assemblages are effective bioindicators of turbidity/light regimes and organic enrichment of sediments on coral reefs.

  3. Benthic community composition on submerged reefs in the central Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Roberts, T. E.; Moloney, J. M.; Sweatman, H. P. A.; Bridge, T. C. L.

    2015-06-01

    Community dynamics on coral reefs are often examined only in relatively shallow waters, which are most vulnerable to many disturbances. The Great Barrier Reef World Heritage Area (GBRWHA) includes extensive submerged reefs that do not approach sea level and are within depths that support many coral reef taxa that also occur in shallow water. However, the composition of benthic communities on submerged reefs in the GBRWHA is virtually unknown. We examined spatial patterns in benthic community composition on 13 submerged reefs in the central Great Barrier Reef (GBR) at depths of 10-30 m. We show that benthic communities on submerged reefs include similar species groups to those on neighbouring emergent reefs. The spatial distribution of species groups was well explained by depth and cross-shelf gradients that are well-known determinants of community composition on emergent reefs. Many equivalent species groups occurred at greater depths on submerged reefs, likely due to variability in the hydrodynamic environment among reef morphologies. Hard coral cover and species richness were lowest at the shallowest depth (6 m) on emergent reefs and were consistently higher on submerged reefs for any given depth. These results suggest that disturbances are less frequent on submerged reefs, but evidence that a severe tropical cyclone in 2011 caused significant damage to shallow regions of more exposed submerged reefs demonstrates that they are not immune. Our results confirm that submerged reefs in the central GBR support extensive and diverse coral assemblages that deserve greater attention in ecosystem assessments and management decisions.

  4. The impacts of tourism on coral reef conservation awareness and support in coastal communities in Belize

    NASA Astrophysics Data System (ADS)

    Diedrich, A.

    2007-12-01

    Marine recreational tourism is one of a number of threats to the Belize Barrier Reef but, conversely, represents both a motivation and source of resources for its conservation. The growth of tourism in Belize has resulted in the fact that many coastal communities are in varying stages of a socio-economic shift from dependence on fishing to dependence on tourism. In a nation becoming increasingly dependent on the health of its coral reef ecosystems for economic prosperity, a shift from extractive uses to their preservation is both necessary and logical. Through examining local perception data in five coastal communities in Belize, each attracting different levels of coral reef related tourism, this analysis is intended to explore the relationship between tourism development and local coral reef conservation awareness and support. The results of the analysis show a positive correlation between tourism development and coral reef conservation awareness and support in the study communities. The results also show a positive correlation between tourism development and local perceptions of quality of life, a trend that is most likely the source of the observed relationship between tourism and conservation. The study concludes that, because the observed relationship may be dependent on continued benefits from tourism as opposed to a perceived crisis in coral reef health, Belize must pay close attention to tourism impacts in the future. Failure to do this could result in a destructive feedback loop that would contribute to the degradation of the reef and, ultimately, Belize’s diminished competitiveness in the ecotourism market.

  5. Sandstone Formations in Capitol Reef

    USGS Multimedia Gallery

    Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  6. Artificial Reefs and Ocean Dumping.

    ERIC Educational Resources Information Center

    Glueck, Richard D.

    1983-01-01

    Activities and instructional strategies for two multigrade lessons are provided. Activity objectives include describing an artificial reef (such as a sunken ocean liner) as an ecosystem, knowing animal types in the ecosystem, and describing a food web. (JN)

  7. Fish assemblages on estuarine artificial reefs: natural rocky-reef mimics or discrete assemblages?

    PubMed

    Folpp, Heath; Lowry, Michael; Gregson, Marcus; Suthers, Iain M

    2014-01-01

    If the primary goal of artificial reef construction is the creation of additional reef habitat that is comparable to adjacent natural rocky-reef, then performance should be evaluated using simultaneous comparisons with adjacent natural habitats. Using baited remote underwater video (BRUV) fish assemblages on purpose-built estuarine artificial reefs and adjacent natural rocky-reef and sand-flat were assessed 18 months post-deployment in three south-east Australian estuaries. Fish abundance, species richness and diversity were found to be greater on the artificial reefs than on either naturally occurring reef or sand-flat in all estuaries. Comparisons within each estuary identified significant differences in the species composition between the artificial and natural rocky-reefs. The artificial reef assemblage was dominated by sparid species including Acanthopagrus australis and Rhabdosargus sarba. The preference for a range of habitats by theses sparid species is evident by their detection on sand-flat, natural rocky reef and artificial reef habitats. The fish assemblage identified on the artificial reefs remained distinct from the adjacent rocky-reef, comprising a range of species drawn from naturally occurring rocky-reef and sand-flat. In addition, some mid-water schooling species including Trachurus novaezelandiae and Pseudocaranx georgianus were only identified on the artificial reef community; presumably as result of the reef's isolated location in open-water. We concluded that estuarine artificial reef assemblages are likely to differ significantly from adjacent rocky-reef, potentially as a result of physical factors such as reef isolation, coupled with species specific behavioural traits such as the ability of some species to traverse large sand flats in order to locate reef structure, and feeding preferences. Artificial reefs should not be viewed as direct surrogates for natural reef. The assemblages are likely to remain distinct from naturally occurring habitat comprised of species that reside on a range of adjacent natural habitats. PMID:23755106

  8. Home Reef, South Pacific

    NASA Technical Reports Server (NTRS)

    2006-01-01

    In the South Pacific, south of Late Island along the Tofua volcanic arc in Tonga, a new volcanic island Home Reef is being re-born. The island is thought to have emerged after a volcanic eruption in mid-August that has also spewed large amounts of floating pumice into Tongan waters and sweeping across to Fiji about 350 km (220 miles) to the west of where the new island has formed. In 2004 a similar eruption created an ephemeral island about 0.5 by 1.5 km (0.3 by 0.9 miles) in size; it was no longer visible in an ASTER image acquired November 2005. This simulated natural color image shows the vegetation-covered stratovolcanic island of Late in the upper right. Home Reef is found in the lower left. The two bluish plumes are hot seawater that is laden with volcanic ash and chemicals; the larger one can be traced for more than 14 km (8.4 miles) to the east. The image was acquired October 10, 2006 and covers an area of 24.3 by 30.2 km. It is located at 18.9 degrees South latitude, 174.7 degrees west longitude.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

    Size: 24.3 by 30.2 kilometers (15 by 18.6 miles) Location: 18.9 degrees South latitude, 174.7 degrees West longitude Orientation: North at top Image Data: ASTER bands 3, 2, and 1 Original Data Resolution: 15 meters (49.2 feet) Dates Acquired: October 4, 2006

  9. Analyzing Pathfinder data using virtual reality and superresolved imaging

    NASA Astrophysics Data System (ADS)

    Stoker, Carol R.; Zbinden, Eric; Blackmon, Theodore T.; Kanefsky, Bob; Hagen, Joel; Neveu, Charles; Rasmussen, Daryl; Schwehr, Kurt; Sims, Michael

    1999-04-01

    The Mars Pathfinder mission used a unique capability to rapidly generate and interactively display three-dimensional (3-D) photorealistic virtual reality (VR) models of the Martian surface. An interactive terrain visualization system creates and renders digital terrain models produced from stereo images taken by the Imager for Mars Pathfinder (IMP) camera. The stereo pipeline, an automated machine vision algorithm, correlates features between the left and right images to determine their disparity and computes the corresponding positions using the known camera geometry. These positions are connected to form a polygonal mesh upon which IMP images are overlaid as textures. During the Pathfinder mission, VR models were produced and displayed almost as fast as images were received. The VR models were viewed using MarsMap, an interface that allows the model to be viewed from any perspective driven by a standard three-button computer mouse. MarsMap incorporates graphical representations of the lander and rover and the sequence and spatial locations at which rover data were taken. Graphical models of the rover were placed in the model to indicate the rover position at the end of each day of the mission. Images taken by Sojourner cameras are projected into the model as 2-D ``billboards'' to show their proper perspective. Distance and angle measurements can be made on features viewed in the model using a mouse-driven 3-D cursor and a point-and-click interface. MarsMap was used to assist with archiving and planning Sojourner activities and to make detailed measurements of surface features such as wind streaks and rock size and orientation that are difficult to perform using 2-D images. Superresolution image processing is a computational method for improving image resolution by a factor of n1/2 by combining n independent images. This technique was used on Pathfinder to obtain better resolved images of Martian surface features. We show results from superresolving IMP camera images of six targets including near- and far-field objects and discuss how the resolution improvement aids interpretation. Similar flood deposits can be seen on both of the Twin Peaks that cannot be resolved in raw images. Millimeter-sized pits are resolved on the rocks Wedge and Halfdome. Other rocks at the Pathfinder site exhibit fine-scale layering that is otherwise invisible. Use of the method resulted in the probable discovery of an artifact of intelligent life on Mars: a part of the Pathfinder spacecraft.

  10. Florida Keys NMS: Coral Reefs

    NSDL National Science Digital Library

    Florida Keys National Marine Sanctuary's page with information on coral reefs and links to information on research, restoration and monitoring. Wealth of information on the protection of Florida's coral reefs and the Florida Keys as a whole. Includes an in-class activity for grades K-5, as well as information on a Keys field experience and teacher workshops. Information on safe diving and snorkeling. Education materials available for purchase, including the Seagrass Toolbox.

  11. Mars Pathfinder First Anniversary Special -- Refined Landing Site Location

    NASA Technical Reports Server (NTRS)

    1998-01-01

    It has been one year since NASA's Return to the Red Planet began with the spectacular landing of Mars Pathfinder and its microrover, Sojourner. The spacecraft bounced onto a flood-washed landscape on July 4, 1997.

    Mars Pathfinder was soon joined by the orbiting Mars Global Surveyor on September 11, 1997 (PDT). Mars Global Surveyor's high resolution camera, MOC, took a picture of the Mars Pathfinder landing site region during its 256th orbit on April 22, 1998. This picture--at about 5 meters (11 feet) per pixel--is the best available for the site. The previous best images were from the Viking 1 Orbiter in 1976, and had resolutions of about 38 meters (125 feet) per pixel.

    The MOC image has allowed scientists to determine the exact location of the Mars Pathfinder lander. Unfortunately, the image resolution is not good enough to actually see the lander--nor can any of the familiar boulders (e.g., 'Yogi') be seen at this resolution.

    Using the MOC image, the landing site location has been refined by Dr. Michael Malin, Principal Investigator for the Mars Global Surveyor MOC Team and a Participating Scientist on the Mars Pathfinder mission. The images above illustrate how the landing site was located by using the 'sight lines' published by T. Parker (Jet Propulsion Laboratory, Pasadena, CA) and topographic map provided by R. Kirk (U.S. Geological Survey, Flagstaff, AZ).

    Left image: MOC image 25603 subframe, shown at 15 meters (about 50 feet) per pixel resolution. Small, colored box is a topographic map of the Mars Pathfinder landing site produced by the U.S. Geological Survey (Flagstaff, AZ) from Mars Pathfinder stereographic images . Dark, heavy lines are 'sight lines' to various landmarks seen along the horizon in Mars Pathfinder camera images, measured by T. Parker and matched to features seen in Viking Orbiter images. These lines were published in Science, v. 278, p. 1746, December 5, 1997. The lighter, thinner sightlines are the same lines, adjusted to match the same features as seen in the higher resolution MOC image 25603. These lines indicate the location of the landing site to within a few hundred meters/yards. The colored box--the topographic map--has been placed at the location of the actual landing site. The lander and rover would be located at the center of the colored box. The white box shows the context of the image to the right. North is up, illumination is from the lower right.

    Top right image: Location of Mars Pathfinder lander and Sojourner Rover, relative to Mars Global Surveyor MOC image obtained April 1998. The famous 'Twin Peaks'-- first seen by the lander on July 4, 1997--are shown at the lower left. The scale bar indicates distance in feet and in meters. The colored box is the topographic map of the Mars Pathfinder landing site, derived from Pathfinder camera stereoscopic images by R. Kirk and colleagues. The lander and rover were located in the center of the colored box.

    Bottom right image: Location of Mars Pathfinder landing site in MOC image 25603. The lander is located in the center of the white box. The original resolution of the MOC image was about 3.3 meters (11 feet) per pixel; however, because the region was hazy at the time the picture was taken, the effective resolution is only about 5 meters (16.4 feet) per pixel. Thus, the lander and rover are too small to actually be seen in the image. The colored box, 120 m (just under 400 ft) on a side, is the topographic map of the landing site. The topographic map was made using the stereographic images taken by Mars Pathfinder in 1997. Low areas-- depressions--are blue and purple, high areas--hill--are shown as red. The range of heights is actually fairly small--a total of 4 m (about 13 ft) from dark purple to bright red. The lander is represented within the black dot at the center of the map. A preliminary version of the topographic map that is generally similar to this more refined version was published in Science, v. 278, p. 1736, December 5, 1997.

    Malin Space Science Systems and the Cal

  12. Miocene precursors to Great Barrier Reef

    SciTech Connect

    Davies, P.J.; Symonds, P.A.; Feary, D.A.; Pigram, C.

    1988-01-01

    Huge reefs of Miocene age are present in the Gulf of Papua north of the present-day Great Barrier Reef and to the east on the Marion and Queensland Plateaus. In the Gulf of Papua, Miocene barrier reefs formed the northern forerunner of the Great Barrier Reef, extending for many hundreds of kilometers along the eastern and northern margin of the Australian craton within a developing foreland basin. Barrier reefs, slope pinnacle reefs, and platform reefs are seen in seismic sections and drill holes. Leeside talus deposits testify to the high energy impinging on the eastern margin of these Miocene reefs. The Queensland Plateau is a marginal plateau east of the central Great Barrier Reef and separated from it by a rift trough. Miocene reefs occupied an area of about 50,000 km/sup 2/ and grew on salt-controlled highs on the western margin of the plateau and on a regional basement high extending from the platform interior to its southern margin. Reef growth has continued to the present day, although two major contractions in the area covered by reefs occurred during the Miocene. The Marion Plateau is present directly east of the Great Barrier Reef and during the Micoene formed a 30,000-km/sup 2/ platform with barrier reefs along its northern margin and huge platform reefs and laggons on the platform interior. These reefs grew on a flat peneplained surface, the whole area forming a large shallow epicontinental sea. In all three areas, the middle Miocene formed the acme of reef expansion in the region.

  13. Distribution, abundance, and substrate preferences of demersal reef zooplankton at Lizard Island Lagoon, Great Barrier Reef

    Microsoft Academic Search

    A. L. Alldredge; J. M. King

    1977-01-01

    Demersal zooplankton, those plankton which hide within reef sediments during the day but emerge to swim freely over the reef at night, were sampled quantitatively using emergence traps planced over the substrate at Lizard Island Lagoon, Great Barrier Reef. Densities of zooplankton emerging at night from 6 substrate types (fine, medium, and coarse sand, rubble, living coral and reef rock)

  14. INSTRUCTIONS FOR AUTHORS Coral Reefs Journal of the International Society for Reef Studies

    E-print Network

    van Woesik, Robert

    INSTRUCTIONS FOR AUTHORS Coral Reefs Journal of the International Society for Reef Studies 1. #12;INSTRUCTIONS FOR AUTHORS Coral Reefs Journal of the International Society for Reef Studies 2 Published by Springer Careful adherence to these journal instructions will avoid delays and extra work

  15. Microbiota of the major South Atlantic reef building coral Mussismilia.

    PubMed

    Fernando, Samodha C; Wang, Jia; Sparling, Kimberly; Garcia, Gizele D; Francini-Filho, Ronaldo B; de Moura, Rodrigo L; Paranhos, Rodolfo; Thompson, Fabiano L; Thompson, Janelle R

    2015-02-01

    The Brazilian endemic scleractinian corals, genus Mussismilia, are among the main reef builders of the South Atlantic and are threatened by accelerating rates of disease. To better understand how holobiont microbial populations interact with corals during health and disease and to evaluate whether selective pressures in the holobiont or neutral assembly shape microbial composition, we have examined the microbiota structure of Mussismilia corals according to coral lineage, environment, and disease/health status. Microbiota of three Mussismilia species (Mussismilia harttii, Mussismilia hispida, and Mussismilia braziliensis) was compared using 16S rRNA pyrosequencing and clone library analysis of coral fragments. Analysis of biological triplicates per Mussismilia species and reef site allowed assessment of variability among Mussismilia species and between sites for M. braziliensis. From 173,487 V6 sequences, 6,733 coral- and 1,052 water-associated operational taxonomic units (OTUs) were observed. M. braziliensis microbiota was more similar across reefs than to other Mussismilia species microbiota from the same reef. Highly prevalent OTUs were more significantly structured by coral lineage and were enriched in Alpha- and Gammaproteobacteria. Bacterial OTUs from healthy corals were recovered from a M. braziliensis skeleton sample at twice the frequency of recovery from water or a diseased coral suggesting the skeleton is a significant habitat for microbial populations in the holobiont. Diseased corals were enriched with pathogens and opportunists (Vibrios, Bacteroidetes, Thalassomonas, and SRB). Our study examines for the first time intra- and inter-specific variability of microbiota across the genus Mussismilia. Changes in microbiota may be useful indicators of coral health and thus be a valuable tool for coral reef management and conservation. PMID:25213651

  16. Development and evaluation of the mars pathfinder inflatable airbag landing system

    Microsoft Academic Search

    D. Cadogan; C. Sandy; M. Grahne

    2002-01-01

    The entry, descent, and landing system of the Mars Pathfinder spacecraft includes a unique subsystem of airbags for impact attenuation. The airbag geometric configuration and associated landing dynamic analysis was performed by the Jet Propulsion Laboratory and Sandia National Laboratories (Mars pathfinder airbag impact attenuation system, paper AIAA-95-1552; Mars pathfinder impact, paper AIAA-95-1553). ILC Dover performed detailed design and fabrication

  17. The Tangible Pathfinder Design of a Wayfinding Trainer for the Visually Impaired

    Microsoft Academic Search

    Ehud Sharlin; Yoshifumi Kitamura; Darren Rorabeck; Robert Lederer; Steve Sutphen; Masafumi Takimoto; Fumio Kishino

    We detail our proposal for an orientation and mobility (or wayfinding) trainer for the visually impaired—the Tangible Pathfinder. The Tangible Pathfinder allows autonomous learning of a new setting, self-assessment of the resulting cognitive map, and eventually on-site mobility assistance when physically walking through the environment. The Tangible Pathfinder integrates a tablet-like tangible user interface (TUI) which tracks a set of

  18. 2005 PathfinderPlus Aero-Elastic Research Flight

    NASA Technical Reports Server (NTRS)

    Navarro, Robert

    2005-01-01

    This viewgraph presentation describes the 2005 Pathfinder along with an investigation of its aeroelastic responses. The contents include: 1) HALE Class of Vehicles; 2) Aero-elastic Research Flights Overall Objective; 3) General Arrangement; 4) Sensor Locations; 5) NASA Ramp Operations; 6) Lakebed Operations; 7) 1st Flight Data Set; 8) Tool development / data usage; 9) HALE Tool Development & Validation; 10) Building a HALE Foundation; 11) Compelling Needs Drive HALE Efforts; and 12) Team Photo

  19. General geology and geomorphology of the Mars Pathfinder landing site

    Microsoft Academic Search

    A. W. Ward; L. R. Gaddis; R. L. Kirk; L. A. Soderblom; K. L. Tanaka; M. P. Golombek; T. J. Parker; Ronald Greeley; R. O. Kuzmin

    1999-01-01

    The Mars Pathfinder (MPF) spacecraft landed on relatively young (late Hesperian-early Amazonian; 3.1-0.7 Ga) plains in Chryse Planitia near the mouth of Ares Vallis. Images returned from the spacecraft reveal a complex landscape of ridges and troughs, large hills and crater rims, rocks and boulders of various sizes and shapes, and surficial deposits, indicating a complex, multistage geologic history of

  20. Debugging complex software systems by means of pathfinder networks

    Microsoft Academic Search

    Emilio Serrano; Arnaud Quirin; Juan A. Botía; Oscar Cordón

    2010-01-01

    This paper introduces a new methodology based on the use of Pathfinder networks (PFNETs) for the debugging of multi-agent systems (MASs). This methodology is specifically designed to develop a forensic analysis (i.e. a debugging process performed on previously recorded data of the MAS run) of MASs showing complex tissues of relationships between agents (i.e. a high complexity in their social

  1. Goldstone radar contributions to Mars Pathfinder landing safety

    NASA Technical Reports Server (NTRS)

    Slade, Martin A.; Jurgens, R. F.

    1994-01-01

    Goldstar radar can provide topography 'profiles', statistical surface roughness, and radar images within a few degrees of the sub-Earth point. Goldstone/Very Large Array (VLA) bistatic radar observations can image the whole disk of Mars with integration times on the order of ten min before pixel smearing occurs. Data from all these radar techniques can be useful for observing the local surface conditions relating to landing safety issues for Mars Pathfinder.

  2. The LTP Experiment on the LISA Pathfinder Mission

    E-print Network

    S. Vitale

    2005-04-14

    We report on the development of the LISA Technology Package (LTP) experiment that will fly on board the LISA Pathfinder mission of the European Space Agency in 2008. We first summarize the science rationale of the experiment aimed at showing the operational feasibility of the so called Transverse-Traceless coordinate frame within the accuracy needed for LISA. We then show briefly the basic features of the instrument and we finally discuss its projected sensitivity and the extrapolation of its results to LISA.

  3. The LTP Experiment on the LISA Pathfinder Mission

    E-print Network

    Vitale, S; Armano, M; Balaguer, E; Benedetti, M; Boatella, C; Bosetti, Peter C; Bortoluzzi, D; Brandt, N; Braxmaier, C; Caldwell, M; Carbone, L; Cavalleri, A; Ciccolella, A; Cristofolini, I; Cruise, M; Da-Lio, M; Danzmann, K; Desiderio, D; Dolesi, R; Dunbar, N; Fichter, W; García, C; García-Berro, E; Garcia-Marin, A F; Gerndt, R; Gioanolio, A; Giardini, D; Gruenagel, R; Hammesfahr, A; Heinzel, G; Hough, J; Holyland, D; Hüller, M; Jennrich, O; Johann, U; Kemble, S; Killow, C; Kolbe, D; Ladgraf, M; Lobo, A; Lotizzo, V; Mance, D; Middleton, K; Nappo, F; Nofrarias, M; Racca, G; Ramos, J; Robertson, D; Sallusti, M; Sandford, M; Sanjuan, J; Sarra, P; Selig, A; Shaul, D; Smart, D; Smit, M; Stagnaro, L; Sumner, T; Tirabassi, C; Tobin, S; Wand, V; Ward, H; Weber, W J; Zweifel, P

    2005-01-01

    We report on the development of the LISA Technology Package (LTP) experiment that will fly on board the LISA Pathfinder mission of the European Space Agency in 2008. We first summarize the science rationale of the experiment aimed at showing the operational feasibility of the so called Transverse-Traceless coordinate frame within the accuracy needed for LISA. We then show briefly the basic features of the instrument and we finally discuss its projected sensitivity and the extrapolation of its results to LISA.

  4. The application accuracy of the PathFinder neurosurgical robot

    Microsoft Academic Search

    Paul S. Morgan; Timothy J. Carter; Stephen Davis; Arsalan Sepehri; Jonathan Punt; Paul Byrne; Alam Moody; Patrick Finlay

    2003-01-01

    We have developed a new technique to measure the overall application accuracy of image-guided stereotactic systems. It has been used to measure the accuracy of the Pathfinder neurosurgical robot, which uses a robot-mounted camera to triangulate fiducial skin markers, virtually eliminating line-of-sight problems experienced by other optical localisation methods. A phantom consisting of plastic spheres on stalks was used. The

  5. Optical Performances of Slewing Mirror Telescope for UFFO-Pathfinder

    Microsoft Academic Search

    S. Jeong; K.-B. Ahn; J. W. Nam; I. H. Park; S.-W. Kim; H. S. Choi; B. Grossan; I. Hermann; A. Jung; Y. W. Kim; J. E. Kim; E. V. Linder; J. Lee; H. Lim; K. W. Min; G. W. Na; K. H. Nam; M. I. Panasyuk; G. F. Smoot; S. Svertilov; Y. D. Suh; N. Vedenkin; I. Yashin; M. H. Zhao

    2011-01-01

    The Ultra-Fast Flash Observatory-Pathfinder (UFFO-P) is to be launched onboard Lomonosov spacecraft in November 2011. It is to measure early UV\\/Optical photons from Gamma Ray Bursts (GRBs). Slewing Mirror Telescope (SMT) is one of two instruments designed for detection of UV\\/Optical images of the GRBs. SMT is a Ritchey-Chr\\\\'etien telescope of 100 mm in diameter with a motorized slewing mirror

  6. JPL Experience with the Mars Pathfinder, Mission Simulation Battery

    NASA Technical Reports Server (NTRS)

    Perrone, Dave; Ewell, Richard

    1997-01-01

    A summary of the Mars Pathfinder Battery is given. The battery survived 47 days at 25 deg. C; it survived a 7 month stand at 10 to -5 deg. C; it met and exceeded 40 ampere-hour capacity for EDL; it met the 30 cycle minimum for Mars surface operation; and the project power profile for MArs surface operation does not yield energy balance.

  7. Grid resolution and solution convergence for Mars Pathfinder forebody

    NASA Technical Reports Server (NTRS)

    Nettelhorst, Heather L.; Mitcheltree, Robert A.

    1994-01-01

    As part of the Discovery Program, NASA Plans to launch a series of probes to Mars. The Mars Pathfinder project is the first of this series with a scheduled Mars arrival in July 1997. The entry vehicle will perform a direct entry into the atmosphere and deliver a lander to the surface. Predicting the entry vehicle's flight performance and designing the forebody heatshield requires knowledge of the expected aerothermodynamic environment. Much of this knowledge can be obtained through computational fluid dynamic (CFD) analysis.

  8. Characteristics of the TOVS Pathfinder Path A Dataset

    Microsoft Academic Search

    J. Susskind; P. Piraino; L. Rokke; L. Iredell; A. Mehta

    1997-01-01

    The TIROS (Television Infrared Observation Satellite) Operational Vertical Sounder (TOVS) Pathfinder Path A dataset is currently a 9-yr dataset, 1985-93, of global fields of surface and atmospheric parameters derived from analysis of HIRS2 and MSU data on the NOAA-9, NOAA-10, NOAA-11, and NOAA-12 polar-orbiting operational meteorological satellites. The retrieved fields include land and ocean surface skin temperature, atmospheric temperature and

  9. Baseline Assessment of Mesophotic Reefs of the Vitória-Trindade Seamount Chain Based on Water Quality, Microbial Diversity, Benthic Cover and Fish Biomass Data

    PubMed Central

    Meirelles, Pedro M.; Amado-Filho, Gilberto M.; Pereira-Filho, Guilherme H.; Pinheiro, Hudson T.; de Moura, Rodrigo L.; Joyeux, Jean-Christophe; Mazzei, Eric F.; Bastos, Alex C.; Edwards, Robert A.; Dinsdale, Elizabeth; Paranhos, Rodolfo; Santos, Eidy O.; Iida, Tetsuya; Gotoh, Kazuyoshi; Nakamura, Shota; Sawabe, Tomoo; Rezende, Carlos E.; Gadelha, Luiz M. R.; Francini-Filho, Ronaldo B.; Thompson, Cristiane; Thompson, Fabiano L.

    2015-01-01

    Seamounts are considered important sources of biodiversity and minerals. However, their biodiversity and health status are not well understood; therefore, potential conservation problems are unknown. The mesophotic reefs of the Vitória-Trindade Seamount Chain (VTC) were investigated via benthic community and fish surveys, metagenomic and water chemistry analyses, and water microbial abundance estimations. The VTC is a mosaic of reef systems and includes fleshy algae dominated rhodolith beds, crustose coralline algae (CCA) reefs, and turf algae dominated rocky reefs of varying health levels. Macro-carnivores and larger fish presented higher biomass at the CCA reefs (4.4 kg per frame) than in the rhodolith beds and rocky reefs (0.0 to 0.1 kg per frame). A larger number of metagenomic sequences identified as primary producers (e.g., Chlorophyta and Streptophyta) were found at the CCA reefs. However, the rocky reefs contained more diseased corals (>90%) than the CCA reefs (~40%) and rhodolith beds (~10%). Metagenomic analyses indicated a heterotrophic and fast-growing microbiome in rocky reef corals that may possibly lead to unhealthy conditions possibly enhanced by environmental features (e.g. light stress and high loads of labile dissolved organic carbon). VTC mounts represent important hotspots of biodiversity that deserve further conservation actions. PMID:26090804

  10. LISA and LISA Pathfinder: Gravitational Wave Observation in Space

    NASA Technical Reports Server (NTRS)

    Guzman, Felipe

    2010-01-01

    The Laser Interferometer Space Antenna (LISA) is a planned NASA-ESA gravitational wave observatory in the frequency range of 0.1 mHz--100 mHz. This observation band is inaccessible to ground-based detectors due to fluctuations in the Earth gravitational field. Gravitational wave sources for LISA include galactic binaries, mergers of supermassive black-hole binaries, extreme-mass-ratio inspirals, and cosmology backgrounds and bursts. LISA is a constellation of three spacecraft separated by 5 million km in an equilateral triangle, whose center follows the Earth in a heliocentric orbit with an orbital phase offset of 20 degrees. Challenging technology is required to ensure pure geodetic trajectories of the six onboard test masses, whose distance fluctuations will be measured by interspacecraft laser interferometers with picometer accuracy. LISA Pathfinder is an ESA-launched technology demonstration mission of key LISA subsystems such as spacecraft control with micronewton thrusters, test mass drag-free control, and precision laser interferometry between free-flying test masses. Ground testing of hardware of the Gravitational Reference Sensor and Optical Metrology subsystems of LISA Pathfinder is currently ongoing. A detailed description of the two missions and an overview of current investigations conducted by the community will be discussed. The current status in development and implementation of LISA Pathfinder pre-flight systems and latest results of the ongoing ground testing efforts will also be presented.

  11. Coral Reefs Journal of the International

    E-print Network

    Shima, Jeff

    1 23 Coral Reefs Journal of the International Society for Reef Studies ISSN 0722-4028 Volume 29 Number 4 Coral Reefs (2010) 29:1019-1022 DOI 10.1007/ s00338-010-0663-9 Guard crabs alleviate deleterious effects of vermetid snails on a branching coral #12;1 23 Your article is protected by copyright and all

  12. Lab 1: Coral Reefs, the Human View

    NSDL National Science Digital Library

    Students are introduced to coral reef ecosystems and the importance of corals to humans. Students watch the IMAX film Coral Reef Adventure to experience the human view of coral reefs through the eyes of ocean explorers and underwater filmmakers Howard and Michele Hall. The students then use microscopes to examine coral and identify its features.

  13. Co-factors of LIM-HD transcription factors in neural development and axon pathfinding in zebrafish 

    E-print Network

    Zhong, Zhen

    2012-06-22

    The zebrafish neuromuscular system is an elegant model to study neural development. To reveal a specific programme for zebrafish motor axon pathfinding I established a method to selectively block motor axon pathfinding ...

  14. Subterranean Groundwater Nutrient Input to Coastal Oceans and Coral Reef Sustainability

    NASA Astrophysics Data System (ADS)

    Paytan, A.; Street, J. H.

    2003-12-01

    Coral reefs are often referred to as the tropical rain forests of the oceans because of their high productivity and biodiversity. Recent observations in coral reefs worldwide have shown clear degradation in water quality and coral reef health and diversity. The implications of this are severe, including tremendous economic losses mostly though fishing and tourism. Nutrient loading has been implicated as one possible cause for the ecosystem decline. A previously unappreciated potential source of nutrient loading is submarine ground water discharge (SGW). Ground water in many cases has high nutrient content from sewage pollution and fertilizer application for agriculture and landscaping. To better understand the effect of this potential source of nutrient input and degrading water quality, we are exploring the contribution of SGW to the nutrient levels in coral reefs. A key to this approach is determining the amount and source of SGW that flows into the coast as well as its nutrient concentrations. The SGW flux and associated input of chemical dissolved load (nutrient, DOC, trace elements and other contaminants) is quantified using naturally occurring Ra isotopes. Radium isotopes have been shown to be excellent tracers for SGW inputs into estuaries and coastal areas (Moore, 1996; Hussain et al., 1999; Kerst et al., 2000). Measurements of Ra activity within the coral reef, the lagoons and the open waters adjacent to the reef provide valuable information regarding the input of Ra as well as nutrients and possibly pollutant from groundwater discharge. Through this analysis the effect of SGD on the delicate carbon and nutrient balance of the fragile coral reef ecosystem could be evaluated. In addition to quantifying the contribution of freshwater to the nutrient mass balance in the reef, information regarding the length of time a water parcel has remained in the near-shore region over the reef can be estimated using the Ra isotope quartet.

  15. Coral Skeletons Provide Historical Evidence of Phosphorus Runoff on the Great Barrier Reef

    PubMed Central

    Mallela, Jennie; Lewis, Stephen E.; Croke, Barry

    2013-01-01

    Recently, the inshore reefs of the Great Barrier Reef have declined rapidly because of deteriorating water quality. Increased catchment runoff is one potential culprit. The impacts of land-use on coral growth and reef health however are largely circumstantial due to limited long-term data on water quality and reef health. Here we use a 60 year coral core record to show that phosphorus contained in the skeletons (P/Ca) of long-lived, near-shore Porites corals on the Great Barrier Reef correlates with annual records of fertiliser application and particulate phosphorus loads in the adjacent catchment. Skeletal P/Ca also correlates with Ba/Ca, a proxy for fluvial sediment loading, again linking near-shore phosphorus records with river runoff. Coral core records suggest that phosphorus levels increased 8 fold between 1949 and 2008 with the greatest levels coinciding with periods of high fertiliser-phosphorus use. Periods of high P/Ca correspond with intense agricultural activity and increased fertiliser application in the river catchment following agricultural expansion and replanting after cyclone damage. Our results demonstrate how coral P/Ca records can be used to assess terrestrial nutrient loading of vulnerable near-shore reefs. PMID:24086606

  16. Lookahead Pathology in Real-Time Path-Finding Vadim Bulitko (bulitko@ualberta.ca)

    E-print Network

    Lu?trek, Mitja

    Lookahead Pathology in Real-Time Path-Finding Vadim Bulitko (bulitko@ualberta.ca) University to produce better actions · Sometimes the opposite is true: pathology Setting · Path-finding in grid world of pathology: number of lookahead depths where error is larger than at the previous depth · 1,000 problems (map

  17. Lookahead Pathology in Real-Time Path-Finding Mitja Lustrek (mitja.lustrek@ijs.si)

    E-print Network

    Lu?trek, Mitja

    Lookahead Pathology in Real-Time Path-Finding Mitja Lustrek (mitja.lustrek@ijs.si) Jozef Stefan to produce better actions · Sometimes the opposite is true: pathology Setting · Path-finding in grid world of pathology: number of lookahead depths where error is larger than at the previous depth · 1,000 problems (map

  18. Thinking Too Much: Pathology in Pathfinding Mitja Lustrek (mitja.lustrek@ijs.si)

    E-print Network

    Lu?trek, Mitja

    Thinking Too Much: Pathology in Pathfinding Mitja Lustrek (mitja.lustrek@ijs.si) Jozef Stefan actions · Sometimes the opposite is true: pathology Setting · Pathfinding in grid world on maps from of a suboptimal move · Degree of pathology = number of lookahead depths where error is larger than

  19. Lookahead Pathology in Real-Time Path-Finding Vadim Bulitko

    E-print Network

    Lu?trek, Mitja

    Lookahead Pathology in Real-Time Path-Finding Vadim Bulitko University of Alberta, Department; Beal 1980). This phenomenon has been termed the minimax pathology. Recently pathological behavior investigate lookahead pathology in real-time path-finding on maps from commercial computer games. Pathology

  20. Automatic On-demand Delegation of Calls in Java PathFinder

    E-print Network

    van Breugel, Franck

    Automatic On-demand Delegation of Calls in Java PathFinder Nastaran Shafiei1 and Franck van Breugel of Computer Science, University of Oxford, UK Abstract. Java PathFinder (JPF) has matured into a model checker that can be used to verify industrial Java applications. Such applica- tions are characterized by both

  1. Reduction and Analysis of Meteorology Data from the Mars Pathfinder Lander

    NASA Technical Reports Server (NTRS)

    Murphy, James R.; Bridger, Alison F. C.; Haberle, Robert M.

    1998-01-01

    Dr. James Murphy is a member of the Mars Pathfinder Atmospheric Structure Investigation Meteorology (ASI/MET) Science Team. The activities of Dr. Murphy, and his collaborators are summarized in this report, which reviews the activities in support of the analysis of the meteorology data from the Mars Pathfinder Lander.

  2. From paper to electronic, the evolution of pathfinders: a review of the literature

    Microsoft Academic Search

    Luigina Vileno

    2007-01-01

    Purpose – The purpose of this paper is to provide a review of the literature on pathfinders, from the 1970s to the present. Design\\/methodology\\/approach – The paper reviews a range of publications which describe the methodology of pathfinders, provide practical advice and information, present research results, to aid librarians and library administrators in how to best manage the production and

  3. PathFinder: a negotiation-based performance-driven router for FPGAs

    Microsoft Academic Search

    Larry McMurchie; Carl Ebeling

    1995-01-01

    Routing FPGAs is a challenging problem because of the relative scarcity of routing resources, both wires and connection points. This can lead either to slow implementations caused by long wiring paths that avoid congestion or a failure to route all signals. This paper presents PathFinder, a router that balances the goals of performance and routability. PathFinder uses an iterative algorithm

  4. NOAA Coral Reef Watch: Remote Sensing and Coral Reefs

    NSDL National Science Digital Library

    Developed by a fifth grade teacher, the Remote Sensing and Coral Reefs curriculum includes lesson plans, which feature links to additional information, and PowerPoint presentations. Topics discussed include altimetry, phytoplankton and ocean color, symbiosis and coral anatomy, sea surface temperature and coral bleaching, and conservation. The lesson plans can be used in sequence or by themselves.

  5. Laser Interferometry for Gravitational Wave Observation: LISA and LISA Pathfinder

    NASA Technical Reports Server (NTRS)

    Guzman, Felipe

    2010-01-01

    The Laser Interferometer Space Antenna (LISA) is a planned NASA-ESA gravitational wave observatory in the frequency range of 0.1mHz-100mHz. This observation band is inaccessible to ground-based detectors due to the large ground motions of the Earth. Gravitational wave sources for LISA include galactic binaries, mergers of supermasive black-hole binaries, extreme-mass-ratio inspirals, and possibly from as yet unimagined sources. LISA is a constellation of three spacecraft separated by 5 million km in an equilateral triangle, whose center follows the Earth in a heliocentric orbit with an orbital phase offset oF 20 degrees. Challenging technology is required to ensure pure geodetic trajectories of the six onboard test masses, whose distance fluctuations will be measured by interspacecraft laser interferometers with picometer accuracy. LISA Pathfinder is an ESA-launched technology demonstration mission of key LISA subsystems such us spacecraft control with micro-newton thrusters, test mass drag-free control, and precision laser interferometry between free-flying test masses. Ground testing of flight hardware of the Gravitational Reference Sensor and Optical Metrology subsystems of LISA Pathfinder is currently ongoing. An introduction to laser interferometric gravitational wave detection, ground-based observatories, and a detailed description of the two missions together with an overview of current investigations conducted by the community will bc discussed. The current status in development and implementation of LISA Pathfinder pre-flight systems and latest results of the ongoing ground testing efforts will also be presented

  6. Neural Pathfinding on Uni- and Multidirectional Photopolymerized Micropatterns

    PubMed Central

    2015-01-01

    Overcoming signal resolution barriers of neural prostheses, such as the commercially available cochlear impant (CI) or the developing retinal implant, will likely require spatial control of regenerative neural elements. To rationally design materials that direct nerve growth, it is first necessary to determine pathfinding behavior of de novo neurite growth from prosthesis-relevant cells such as spiral ganglion neurons (SGNs) in the inner ear. Accordingly, in this work, repeating 90° turns were fabricated as multidirectional micropatterns to determine SGN neurite turning capability and pathfinding. Unidirectional micropatterns and unpatterned substrates are used as comparisons. Spiral ganglion Schwann cell alignment (SGSC) is also examined on each surface type. Micropatterns are fabricated using the spatial reaction control inherent to photopolymerization with photomasks that have either parallel line spacing gratings for unidirectional patterns or repeating 90° angle steps for multidirectional patterns. Feature depth is controlled by modulating UV exposure time by shuttering the light source at given time increments. Substrate topography is characterized by white light interferometry and scanning electron microscopy (SEM). Both pattern types exhibit features that are 25 ?m in width and 7.4 ± 0.7 ?m in depth. SGN neurites orient randomly on unpatterned photopolymer controls, align and consistently track unidirectional patterns, and are substantially influenced by, but do not consistently track, multidirectional turning cues. Neurite lengths are 20% shorter on multidirectional substrates compared to unidirectional patterns while neurite branching and microfeature crossing events are significantly higher. For both pattern types, the majority of the neurite length is located in depressed surface features. Developing methods to understand neural pathfinding and to guide de novo neurite growth to specific stimulatory elements will enable design of innovative biomaterials that improve functional outcomes of devices that interface with the nervous system. PMID:24911660

  7. NASA Ocean Altimeter Pathfinder Project. Report 1; Data Processing Handbook

    NASA Technical Reports Server (NTRS)

    Koblinsky, C. J.; Beckley, Brian D.; Ray, Richard D.; Wang, Yan-Ming; Tsaoussi, Lucia; Brenner, Anita; Williamson, Ron

    1998-01-01

    The NOAA/NASA Pathfinder program was created by the Earth Observing System (EOS) Program Office to determine how satellite-based data sets can be processed and used to study global change. The data sets are designed to be long time-sedes data processed with stable calibration and community consensus algorithms to better assist the research community. The Ocean Altimeter Pathfinder Project involves the reprocessing of all altimeter observations with a consistent set of improved algorithms, based on the results from TOPEX/POSEIDON (T/P), into easy-to-use data sets for the oceanographic community for climate research. This report describes the processing schemes used to produce a consistent data set and two of the products derived f rom these data. Other reports have been produced that: a) describe the validation of these data sets against tide gauge measurements and b) evaluate the statistical properties of the data that are relevant to climate change. The use of satellite altimetry for earth observations was proposed in the early 1960s. The first successful space based radar altimeter experiment was flown on SkyLab in 1974. The first successful satellite radar altimeter was flown aboard the Geos-3 spacecraft between 1975 and 1978. While a useful data set was collected from this mission for geophysical studies, the noise in the radar measured and incomplete global coverage precluded ft from inclusion in the Ocean Altimeter Pathfinder program. This program initiated its analysis with the Seasat mission, which was the first satellite radar altimeter flown for oceanography.

  8. Symbolic PathFinder: Symbolic Execution of Java Bytecode

    NASA Technical Reports Server (NTRS)

    Pasareanu, Corina S.; Rungta, Neha

    2010-01-01

    Symbolic Pathfinder (SPF) combines symbolic execution with model checking and constraint solving for automated test case generation and error detection in Java programs with unspecified inputs. In this tool, programs are executed on symbolic inputs representing multiple concrete inputs. Values of variables are represented as constraints generated from the analysis of Java bytecode. The constraints are solved using off-the shelf solvers to generate test inputs guaranteed to achieve complex coverage criteria. SPF has been used successfully at NASA, in academia, and in industry.

  9. The LISA PathFinder DMU Software, a Global Overview

    NASA Astrophysics Data System (ADS)

    Gesa, L.; Martin, V.; Conchillo, A.; Lobo, A.; Lloro, I.

    2013-01-01

    During the last 6 years, the IEEC software team has developed the Data Management Unit (DMU) software. It is a critical piece of engineering in the Lisa Pathfinder mission, in charge of the primary processing of data generated by the Phasemeter, acting also as an interface between the whole LISA Technology Package (LTP) and the On-Board Computer (OBC). It also manages and controls the diagnostics systems (Heaters, coils, magnetometers, radiation monitor, thermometers). This article briefly summarizes all the work performed, describing the complex environment built around the application generation.

  10. Closed Loop Simulations of the Thermal Experiments in LISA Pathfinder

    NASA Astrophysics Data System (ADS)

    Gibert, F.; Nofrarias, M.; Karnesis, N.; Díaz-Aguiló, M.; Mateos, I.; Lobo, A.; Gesa, L.; Martín, V.; Lloro, I.

    2013-01-01

    The thermal experiments to be carried out onboard LISA Pathfinder (LPF) will provide essential information of the dependences of the instrument with respect to temperature variations. These thermal experiments must be modelled and simulated both to be validated for mission operations purposes and also to develop a data analysis tool able to characterise the temperature noise contribution to the instrument performance. Here we will present the models developed and the simulated signals for some of the experiments together with the corresponding interferometer readouts, the latter being computed by combining the thermal models with the global LTP (LISA Technology Package) simulator of the LTP Data Analysis team.

  11. Mid-late Holocene Reef Growth and Sedimentation History at Inshore Fringing Reefs in the Central Great Barrier Reef, Australia

    NASA Astrophysics Data System (ADS)

    Ryan, E.; Smithers, S.; Lewis, S.; Zhao, J. X.; Clark, T.

    2014-12-01

    Inshore coral reefs of Australia's Great Barrier Reef (GBR) are threatened by terrestrial sediment loads that are argued to have increased by five to six times since coastal catchments were settled by Europeans in the mid-1850s. Nutrient and contaminant delivery to the inshore GBR has also increased over this period. However, direct evidence that European colonisation has changed the ecology of inshore reefs on the GBR remains limited, partly due to a lack of baseline historical data on coral reef growth. Coral reefs have been growing in inshore areas of the GBR since 6 or 7 ky BP, and have experienced natural fluctuations in terrestrial sediment loads over this period. For example, floods associated with episodic cyclones and major rainfall events often deliver pulses of sediment, especially if they follow prolonged dry spells. To better understand this history of sediment influx and reef development, we have examined in detail the chronostratigraphy of several inshore GBR reefs that have grown since the mid-Holocene. Here, we report on eight percussion cores collected at Bramston Reef (148°15'E, 20°03'S). Two cores terminate in the pre-Holocene substrate and therefore capture the entire Holocene sequence of both reef framework and terrigenous sediment matrix. Results from detailed core analyses indicate variable sedimentation patterns throughout the period of reef development. Furthermore, reef ecological condition and variability through the mid-late Holocene is described using palaeoecological analyses. We explore the impacts of sedimentation variability on reef growth and ecology, and compare reef ecological condition pre- and post-European colonisation.

  12. Teacher/Pathfinder: An Educational Internet Village

    NSDL National Science Digital Library

    This well-organized and very useful metasite has something for everyone involved in K-12 education professionally or as a parent. The site is essentially a collection of links to a large number of on-line resources grouped in five categories. The Community Center currently offers two topics: Improving Education and Model Consortia, the first containing a large number of Department of Education publications. The Support Offices section contains resources of interest to a variety of K-12 professionals: teachers, librarians, administrators, and nurses. The Schoolhouse is appropriately the largest area, and it features assessment and general education tools as well as subject area resources, including social studies and technology. Visitors to the Parent Building will find a list of Family-Friendly Internet Sites, tips for involving the family in education, and Family Health Resources. Finally, the Professional Development section covers a number of topics, including tutorials for using technology in education. This metasite is especially recommended because unlike many other K-12 sites, it aims beyond the teachers and includes valuable information for families and all K-12 professionals.

  13. DYNAMIC CHANGES IN COLORED DISSOLVED ORGANIC MATTER AND TOTAL SUSPENDED MATTER CONTROL UV EXPOSURE OF CORAL REEFS IN THE FLORIDA KEYS

    EPA Science Inventory

    Variation in ultraviolet (UV) light exposure is one important environmental factor that influences the health of coral reefs. Here we present evidence that the reef tract in the Florida Keys experiences significantly higher variability in UV exposure than other surrounding coast...

  14. Sandstone Spire in Capitol Reef

    USGS Multimedia Gallery

    A view of a sandstone spire in Capitol Reef National Park. This area, known as the Fruita, is made up of three primary layers. The bottom sandstone layer is known as the Moenkopi Formation and is about 245 million years old. The middle gray-green layer is known as the Chinle Formation and was laid d...

  15. The future of coral reefs

    NASA Astrophysics Data System (ADS)

    Knowlton, Nancy

    2001-05-01

    Coral reefs, with their millions of species, have changed profoundly because of the effects of people, and will continue to do so for the foreseeable future. Reefs are subject to many of the same processes that affect other human-dominated ecosystems, but some special features merit emphasis: (i) Many dominant reef builders spawn eggs and sperm into the water column, where fertilization occurs. They are thus particularly vulnerable to Allee effects, including potential extinction associated with chronic reproductive failure. (ii) The corals likely to be most resistant to the effects of habitat degradation are small, short-lived "weedy" corals that have limited dispersal capabilities at the larval stage. Habitat degradation, together with habitat fragmentation, will therefore lead to the establishment of genetically isolated clusters of inbreeding corals. (iii) Increases in average sea temperatures by as little as 1°C, a likely result of global climate change, can cause coral "bleaching" (the breakdown of coral-algal symbiosis), changes in symbiont communities, and coral death. (iv) The activities of people near reefs increase both fishing pressure and nutrient inputs. In general, these processes favor more rapidly growing competitors, often fleshy seaweeds, and may also result in explosions of predator populations. (v) Combinations of stress appear to be associated with threshold responses and ecological surprises, including devastating pathogen outbreaks. (vi) The fossil record suggests that corals as a group are more likely to suffer extinctions than some of the groups that associate with them, whose habitat requirements may be less stringent.

  16. Reef tanks, public aquariums and

    E-print Network

    Watson, Andrew

    have modified, spooned-shaped chelae to feed on both fleshy and filamentous algae. However, such as the glass-anemone (Aiptasia pallida), the fireworm (Hermodice carunculata) and the bubble algae (Valonia spp (Decapoda: Brachyura: Majidae) are utilized in reef aquaria to control nuisance algae, particularly bubble

  17. Battelle developing reefs to ease habitat losses

    SciTech Connect

    Not Available

    1993-04-01

    Artificial reefs may be the answer to solving a worldwide problem of declining fish habitats, or they may only be good for creating fishing spots. Researchers at Battelle's Ocean Sciences Laboratory in Duxbury, Massachusetts, are studying artificial reefs in the Delaware River to determine if they are a solution to habitat losses in estuaries and coastal regions. [open quotes]Right now, we don't know if the fish are using the reefs simply as a grazing land, and then moving on, or if they're using the areas to colonize,[close quotes] said researcher Karen Foster. [open quotes]Ultimately, we hope to find they are colonizing.[close quotes] In 1989, Battelle researchers placed 16 prefabricated concrete reefs 45 feet deep in Delaware Bay. The reefs were placed in clusters of four, and monitoring began the following year. The federal government ordered the reefs placed in the bay as a mitigation technique for fish habitat that was lost when the river was dredged for navigational purposes. Researchers examined the reefs twice last summer. It will take five years, Foster said, before researchers can determine if the reefs are increasing the fish population. Early tests show, however, the populations of mussels, sponges, corals, and anemones increased by up to 150 percent over an area of bay bottom where the reefs were placed. Divers take crustacean samples from the reefs, and fish are caught near the reefs for examination. Researchers dissect the fish stomachs and analyze the contents to determine if they have been feeding at the reefs. [open quotes]If we find blue mussels in the stomach of the fish, that's great because we know that blue mussels are growing on the reef,[close quotes] Foster said.

  18. 78 FR 67128 - Coral Reef Conservation Program; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-08

    ...National Oceanic and Atmospheric Administration Coral Reef Conservation Program; Meeting AGENCY: Coral Reef Conservation Program, Office of Ocean...hereby given of a public meeting of the U.S. Coral Reef Task Force (USCRTF). The meeting...

  19. 75 FR 48934 - Coral Reef Conservation Program Implementation Guidelines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-12

    ...100726313-0313-01] RIN 0648-ZC19 Coral Reef Conservation Program Implementation...Final Implementation Guidelines for the Coral Reef Conservation Program...Implementation Guidelines (Guidelines) for the Coral Reef Conservation Program (CRCP or...

  20. Mars Pathfinder and Mars Global Surveyor Outreach Compilation

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This videotape is a compilation of the best NASA JPL (Jet Propulsion Laboratory) videos of the Mars Pathfinder and Mars Global Surveyor missions. The mission is described using animation and narration as well as some actual footage of the entire sequence of mission events. Included within these animations are the spacecraft orbit insertion; descent to the Mars surface; deployment of the airbags and instruments; and exploration by Sojourner, the Mars rover. JPL activities at spacecraft control during significant mission events are also included at the end. The spacecraft cameras pan the surrounding Mars terrain and film Sojourner traversing the surface and inspecting rocks. A single, brief, processed image of the Cydonia region (Mars face) at an oblique angle from the Mars Global Surveyor is presented. A description of the Mars Pathfinder mission, instruments, landing and deployment process, Mars approach, spacecraft orbit insertion, rover operation are all described using computer animation. Actual color footage of Sojourner as well as a 360 deg pan of the Mars terrain surrounding the spacecraft is provided. Lower quality black and white photography depicting Sojourner traversing the Mars surface and inspecting Martian rocks also is included.

  1. Disentangling the magnetic force noise contribution in LISA Pathfinder

    NASA Astrophysics Data System (ADS)

    Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Brandt, N.; Bursi, A.; Caleno, M.; Cavalleri, A.; Cesarini, A.; Cruise, M.; Danzmann, K.; Diepholz, I.; Dolesi, R.; Dunbar, N.; Ferraioli, L.; Ferroni, V.; Fitzsimons, E.; Freschi, M.; Gallegos, J.; García Marirrodriga, C.; Gerndt, R.; Gesa, L. I.; Gibert, F.; Giardini, D.; Giusteri, R.; Grimani, C.; Harrison, I.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hueller, M.; Huesler, J.; Inchauspé, H.; Jennrich, O.; Jetzer, P.; Johlander, B.; Karnesis, N.; Kaune, B.; Korsakova, N.; Killow, C.; Lloro, I.; Maarschalkerweerd, R.; Madden, S.; Mance, D.; Martín, V.; Martin-Porqueras, F.; Mateos, I.; McNamara, P.; Mendes, J.; Mendes, L.; Moroni, A.; Nofrarias, M.; Paczkowski, S.; Perreur-Lloyd, M.; Petiteau, A.; Pivato, P.; Plagnol, E.; Prat, P.; Ragnit, U.; Ramos-Castro, J.; Reiche, J.; Romera Perez, J. A.; Robertson, D.; Rozemeijer, H.; Russano, G.; Sarra, P.; Schleicher, A.; Slutsky, J.; Sopuerta, C. F.; Sumner, T.; Texier, D.; Thorpe, J.; Trenkel, C.; Tu, H. B.; Vitale, S.; Wanner, G.; Ward, H.; Waschke, S.; Wass, P.; Wealthy, D.; Wen, S.; Weber, W.; Wittchen, A.; Zanoni, C.; Ziegler, T.; Zweifel, P.

    2015-05-01

    Magnetically-induced forces on the inertial masses on-board LISA Pathfinder are expected to be one of the dominant contributions to the mission noise budget, accounting for up to 40%. The origin of this disturbance is the coupling of the residual magnetization and susceptibility of the test masses with the environmental magnetic field. In order to fully understand this important part of the noise model, a set of coils and magnetometers are integrated as a part of the diagnostics subsystem. During operations a sequence of magnetic excitations will be applied to precisely determine the coupling of the magnetic environment to the test mass displacement using the on-board magnetometers. Since no direct measurement of the magnetic field in the test mass position will be available, an extrapolation of the magnetic measurements to the test mass position will be carried out as a part of the data analysis activities. In this paper we show the first results on the magnetic experiments during an end- to-end LISA Pathfinder simulation, and we describe the methods under development to map the magnetic field on-board.

  2. NASA Ocean Altimeter Pathfinder Project. Report 2; Data Set Validation

    NASA Technical Reports Server (NTRS)

    Koblinsky, C. J.; Ray, Richard D.; Beckley, Brian D.; Bremmer, Anita; Tsaoussi, Lucia S.; Wang, Yan-Ming

    1999-01-01

    The NOAA/NASA Pathfinder program was created by the Earth Observing System (EOS) Program Office to determine how existing satellite-based data sets can be processed and used to study global change. The data sets are designed to be long time-series data processed with stable calibration and community consensus algorithms to better assist the research community. The Ocean Altimeter Pathfinder Project involves the reprocessing of all altimeter observations with a consistent set of improved algorithms, based on the results from TOPEX/POSEIDON (T/P), into easy-to-use data sets for the oceanographic community for climate research. Details are currently presented in two technical reports: Report# 1: Data Processing Handbook Report #2: Data Set Validation This report describes the validation of the data sets against a global network of high quality tide gauge measurements and provides an estimate of the error budget. The first report describes the processing schemes used to produce the geodetic consistent data set comprised of SEASAT, GEOSAT, ERS-1, TOPEX/ POSEIDON, and ERS-2 satellite observations.

  3. Delineating optimal settlement areas of juvenile reef fish in Ngederrak Reef, Koror state, Republic of Palau.

    PubMed

    Ticzon, Victor S; Foster, Greg; David, Laura T; Mumby, Peter J; Samaniego, Badi R; Madrid, Val Randolf

    2015-01-01

    Establishing the effectiveness of habitat features to act as surrogate measures of diversity and abundance of juvenile reef fish provides information that is critical to coral reef management. When accurately set on a broader spatial context, microhabitat information becomes more meaningful and its management application becomes more explicit. The goal of the study is to identify coral reef areas potentially important to juvenile fishes in Ngederrak Reef, Republic of Palau, across different spatial scales. To achieve this, the study requires the accomplishment of the following tasks: (1) structurally differentiate the general microhabitat types using acoustics; (2) quantify microhabitat association with juvenile reef fish community structure; and (3) conduct spatial analysis of the reef-wide data and locate areas optimal for juvenile reef fish settlement. The results strongly suggest the importance of branching structures in determining species count and abundance of juvenile reef fish at the outer reef slope of Ngederrak Reef. In the acoustic map, the accurate delineation of these features allowed us to identify reef areas with the highest potential to harbor a rich aggregation of juvenile reef fish. Using a developed spatial analysis tool that ranks pixel groups based on user-defined parameters, the reef area near the Western channel of Ngederrak is predicted to have the most robust aggregation of juvenile reef fish. The results have important implications not only in management, but also in modeling the impacts of habitat loss on reef fish community. At least for Ngederrak Reef, the results advanced the utility of acoustic systems in predicting spatial distribution of juvenile fish. PMID:25394769

  4. Live coral cover in the fossil record: an example from Holocene reefs of the Dominican Republic

    NASA Astrophysics Data System (ADS)

    Lescinsky, H.; Titus, B.; Hubbard, D.

    2012-06-01

    Fossil reefs hold important ecological information that can provide a prehuman baseline for understanding recent anthropogenic changes in reefs systems. The most widely used proxy for reef "health," however, is live coral cover, and this has not been quantified in the fossil record because it is difficult to establish that even adjacent corals were alive at the same time. This study uses microboring and taphonomic proxies to differentiate between live and dead corals along well-defined time surfaces in Holocene reefs of the Enriquillo Valley, Dominican Republic. At Cañada Honda, live coral cover ranged from 59 to 80% along a contemporaneous surface buried by a storm layer, and the reef, as a whole had 33-80% live cover within the branching, mixed, massive and platy zones. These values equal or exceed those in the Dominican Republic and Caribbean today or reported decades ago. The values from the western Dominican Republic provide a geologic baseline against which modern anthropogenic changes in Caribbean reefs can be considered.

  5. 76 FR 59377 - Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-26

    ...Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and Invertebrates...Resources, Spiny Lobster, Queen Conch, and Coral and Reef Associated Plants and Invertebrates...framework procedures for spiny lobster and coral and reef associated plants and...

  6. Uptake of picophytoplankton, bacterioplankton and virioplankton by a fringing coral reef community (Ningaloo Reef, Australia)

    NASA Astrophysics Data System (ADS)

    Patten, N. L.; Wyatt, A. S. J.; Lowe, R. J.; Waite, A. M.

    2011-09-01

    We examined the importance of picoplankton and virioplankton to reef trophodynamics at Ningaloo Reef, (north-western Australia), in May and November 2008. Picophytoplankton ( Prochlorococcus, Synechococcus and picoeukaryotes), bacterioplankton (inclusive of bacteria and Archaea), virioplankton and chlorophyll a (Chl a) were measured at five stations following the consistent wave-driven unidirectional mean flow path of seawater across the reef and into the lagoon. Prochlorococcus, Synechococcus, picoeukaryotes and bacterioplankton were depleted to similar levels (~40% on average) over the fore reef, reef crest and reef flat (=`active reef'), with negligible uptake occurring over the sandy bottom lagoon. Depletion of virioplankton also occurred but to more variable levels. Highest uptake rates, m, of picoplankton occurred over the reef crest, while uptake coefficients, S (independent of cell concentration), were similarly scaled over the reef zones, indicating no preferential uptake of any one group. Collectively, picophytoplankton, bacterioplankton and virioplankton accounted for the uptake of 29 mmol C m-2 day-1, with Synechococcus contributing the highest proportion of the removed C. Picoplankton and virioplankton accounted for 1-5 mmol N m-2 day-1 of the removed N, with bacterioplankton estimated to be a highly rich source of N. Results indicate the importance of ocean-reef interactions and the dependence of certain reef organisms on picoplanktonic supply for reef-level biogeochemistry processes.

  7. Contradictions to Darwin's Evolution of Reef Types in Barrier Reef Relationships

    Microsoft Academic Search

    E. Purdy; E. L. Winterer

    2004-01-01

    The Darwinian progressive subsidence model for the evolution of fringing reefs, barrier reefs and atolls has been generally accepted following the indisputable proof of subsidence provided by drilling results in the Pacific. Nonetheless, there are data that do not fit the expectations of the model, such as the similar lagoon depths of barrier reefs and atolls as opposed to the

  8. Coral reefs. Limited scope for latitudinal extension of reef corals.

    PubMed

    Muir, Paul R; Wallace, Carden C; Done, Terence; Aguirre, J David

    2015-06-01

    An analysis of present-day global depth distributions of reef-building corals and underlying environmental drivers contradicts a commonly held belief that ocean warming will promote tropical coral expansion into temperate latitudes. Using a global data set of a major group of reef corals, we found that corals were confined to shallower depths at higher latitudes (up to 0.6 meters of predicted shallowing per additional degree of latitude). Latitudinal attenuation of the most important driver of this phenomenon-the dose of photosynthetically available radiation over winter-would severely constrain latitudinal coral range extension in response to ocean warming. Latitudinal gradients in species richness for the group also suggest that higher winter irradiance at depth in low latitudes allowed a deep-water fauna that was not viable at higher latitudes. PMID:26045436

  9. Holocene development of the Belize Barrier Reef

    Microsoft Academic Search

    Eberhard Gischler; J. Harold Hudson

    2004-01-01

    Previously, knowledge of the Holocene development of the Belize Barrier Reef (BBR)—the largest reef system in the Atlantic Ocean—was limited to one location (Carrie Bow Cay). We present new data from 11 rotary drill cores taken at 9 locations and 36 radiometric ages that indicate that the BBR was established from >8.26 to 6.68 ky BP on Pleistocene reef limestones,

  10. Coral Reef Protection: A Watershed Approach

    NSDL National Science Digital Library

    United States. Environmental Protection Agency. Office of Water.

    1998-01-01

    This colorful, straightforward site from the Environmental Protection Agency (EPA)'s Oceans and Coastal Protection division (described in the November 25, 1998 Scout Report for Science & Engineering) outlines coral reef basic ecology and protection. About Coral Reefs provides background ecological information on coral reefs; Initiatives and Activities highlights EPA's activities but includes other US initiatives and links to symposia preceedings, factsheets, and other resources; and Related Links provides additional information on coral reef protection from the international, non-governmental (as well as federal), and educational sectors. A selection of recent news items (on the front page) rounds out the site.

  11. Impacts of Artificial Reefs on Surrounding Ecosystems

    NASA Astrophysics Data System (ADS)

    Manoukian, Sarine

    Artificial reefs are becoming a popular biological and management component in shallow water environments characterized by soft seabed, representing both important marine habitats and tools to manage coastal fisheries and resources. An artificial reef in the marine environment acts as an open system with exchange of material and energy, altering the physical and biological characteristics of the surrounding area. Reef stability will depend on the balance of scour, settlement, and burial resulting from ocean conditions over time. Because of the unstable nature of sediments, they require a detailed and systematic investigation. Acoustic systems like high-frequency multibeam sonar are efficient tools in monitoring the environmental evolution around artificial reefs, whereas water turbidity can limit visual dive and ROV inspections. A high-frequency multibeam echo sounder offers the potential of detecting fine-scale distribution of reef units, providing an unprecedented level of resolution, coverage, and spatial definition. How do artificial reefs change over time in relation to the coastal processes? How accurately does multibeam technology map different typologies of artificial modules of known size and shape? How do artificial reefs affect fish school behavior? What are the limitations of multibeam technology for investigating fish school distribution as well as spatial and temporal changes? This study addresses the above questions and presents results of a new approach for artificial reef seafloor mapping over time, based upon an integrated analysis of multibeam swath bathymetry data and geoscientific information (backscatter data analysis, SCUBA observations, physical oceanographic data, and previous findings on the geology and sedimentation processes, integrated with unpublished data) from Senigallia artificial reef, northwestern Adriatic Sea (Italy) and St. Petersburg Beach Reef, west-central Florida continental shelf. A new approach for observation of fish aggregations associated with Senigallia reef based on the analysis of multibeam backscatter data in the water column is also explored. The settlement of the reefs and any terrain change are investigated over time providing a useful description of the local hydrodynamics and geological processes. All the artificial structures (made up by water-based concrete for Senigallia reef and mainly steel for St. Petersburg Beach reef) are identified and those showing substantial horizontal and/or vertical movements are analyzed in detail. Most artificial modules of Senigallia reef are not intact and scour signatures are well depicted around them, indicating reversals of the local current. This is due to both the wind pattern and to the quite close arrangement of the reef units that tend to deflect the bottom flow. As regards to the St. Petersburg Beach reef, all the man-made steel units are still in their upright position. Only a large barge shows a gradual collapse of its south side, and presents well-developed scouring at its east-northeast side, indicating dominant bottom flow from west-southwest to east-northeast. While an overall seafloor depth shallowing of about 0.30 m from down-current deposits was observed for Senigallia reef, an overall deepening of about 0.08 m due to scour was observed at the St. Petersburg Beach reef. Based on the backscatter data interpretation, surficial sediments are coarser in the vicinities of both artificial reefs than corresponding surrounding sediments. Scouring reveals this coarser layer underneath the prevalent mud sediment at Senigallia reef, and the predominant silt sediment at St. Petersburg Beach reef. In the ten years of Senigalia reef study, large-scale variations between clay and silt appear to be directly linked to large flood events that have occurred just prior to the change. As regards the water column investigation, acoustic backscatter from fish aggregations gives detailed information on their morphology and spatial distribution. In addition, relative fish biomass estimates can be extrapolated. Results suggest that most of

  12. Conservation, precaution, and Caribbean reefs

    NASA Astrophysics Data System (ADS)

    Aronson, Richard B.; Precht, William F.

    2006-08-01

    Some authors argue that overfishing is an important reason that reef corals have declined in recent decades. Their reasoning is that overfishing removes herbivores, releasing macroalgae to overgrow and kill the corals. The evidence suggests, however, that global climate change and emergent marine diseases make a far greater contribution to coral mortality, and that macroalgae generally grow on the exposed skeletal surfaces of corals that are already dead. Macroalgal dominance, therefore, is an effect rather than a cause of coral mortality. Marine protected areas (MPAs), which are usually established to protect stocks of reef fish, foster populations of herbivorous fish under at least some circumstances. Increased herbivory can reduce algal cover, potentially accelerating the recovery of coral populations inside MPAs; however, establishing MPAs will have only a limited impact on coral recovery unless policymakers confront the accelerating negative effects of the global-scale sources of coral mortality.

  13. Great Barrier Reef, Queensland, Australia

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Along the coast of Queensland, Australia (18.0S, 147.5E), timbered foothills of the Great Dividing Range separate the semi-arid interior of Queensland from the farmlands of the coastal plains. Prominent cleared areas in the forest indicate deforestation for farm and pasture lands. Offshore, islands and the Great Barrier Reef display sand banks along the southern sides of the structures indicating a dominant southerly wind and current direction.

  14. Coral reef evolution on rapidly subsiding margins

    USGS Publications Warehouse

    Webster, J.M.; Braga, J.C.; Clague, D.A.; Gallup, C.; Hein, J.R.; Potts, D.C.; Renema, W.; Riding, R.; Riker-Coleman, K.; Silver, E.; Wallace, L.M.

    2009-01-01

    A series of well-developed submerged coral reefs are preserved in the Huon Gulf (Papua New Guinea) and around Hawaii. Despite different tectonics settings, both regions have experienced rapid subsidence (2-6??m/ka) over the last 500??ka. Rapid subsidence, combined with eustatic sea-level changes, is responsible for repeated drowning and backstepping of coral reefs over this period. Because we can place quantitative constraints on these systems (i.e., reef drowning age, eustatic sea-level changes, subsidence rates, accretion rates, basement substrates, and paleobathymetry), these areas represent unique natural laboratories for exploring the roles of tectonics, reef accretion, and eustatic sea-level changes in controlling the evolution of individual reefs, as well as backstepping of the entire system. A review of new and existing bathymetric, radiometric, sedimentary facies and numerical modeling data indicate that these reefs have had long, complex growth histories and that they are highly sensitive, recording drowning not only during major deglaciations, but also during high-frequency, small-amplitude interstadial and deglacial meltwater pulse events. Analysis of five generalized sedimentary facies shows that reef drowning is characterized by a distinct biological and sedimentary sequence. Observational and numerical modeling data indicate that on precessional (20??ka) and sub-orbital timescales, the rate and amplitude of eustatic sea-level changes are critical in controlling initiation, growth, drowning or sub-aerial exposure, subsequent re-initiation, and final drowning. However, over longer timescales (> 100-500??ka) continued tectonic subsidence and basement substrate morphology influence broad scale reef morphology and backstepping geometries. Drilling of these reefs will yield greatly expanded stratigraphic sections compared with similar reefs on slowly subsiding, stable and uplifting margins, and thus they represent a unique archive of sea-level and climate changes, as well as a record of the response of coral reefs to these changes over the last six glacial cycles. ?? 2008 Elsevier B.V. All rights reserved.

  15. Structural analyses of the JPL Mars Pathfinder impact

    SciTech Connect

    Gwinn, K.W. [Sandia National Labs., Albuquerque, NM (United States). Material and Structural Mechanics Dept.

    1994-12-31

    The purpose of this paper is to demonstrate that finite element analysis can be used in the design process for high performance fabric structures. These structures exhibit extreme geometric nonlinearity; specifically, the contact and interaction of fabric surfaces with the large deformation which necessarily results from membrane structures introduces great complexity to analyses of this type. All of these features are demonstrated here in the analysis of the Jet Propulsion Laboratory (JPL) Mars Pathfinder impact onto Mars. This lander system uses airbags to envelope the lander experiment package, protecting it with large deformation upon contact. Results from the analysis show the stress in the fabric airbags, forces in the internal tendon support system, forces in the latches and hinges which allow the lander to deploy after impact, and deceleration of the lander components. All of these results provide the JPL engineers with design guidance for the success of this novel lander system.

  16. Mars Pathfinder and the exploration of southern Amazonis Planitia

    NASA Technical Reports Server (NTRS)

    Barlow, Nadine G.

    1994-01-01

    The southern region of Amazonis Planitia provides a variety of target terrains for a roving vehicle such as the Mars Pathfinder Mission. A landing site is proposed at 4 deg N latitude 162 deg W longitude. This area has a reference altitude of between 0 and -1 km and consists of relatively smooth Amazonian-aged deposits within the entire 100 x 200 km landing ellipse. The proposed landing site is within the Upper Member Medusae Fossae Formation deposits (Amu) and near the boundary with Middle Member Medusae Fossae Formation deposits (Amm) and Member 1 Arcadia Formation plains (Aa(sub 1)). Slightly further afield are 107-km-diameter Nicholson crater, its ejecta deposits, and knobby terrain of proposed Hesperian age (HNu). Depending on the exact landing site of the spacecraft and the traverse distance of the rover, these materials also may be sampled.

  17. Soil-like deposits observed by Sojourner, the Pathfinder rover

    USGS Publications Warehouse

    Moore, Henry J.; Bickler, Donald B.; Crisp, Joy A.; Eisen, Howard J.; Gensler, Jeffrey A.; Haldemann, Albert F.C.; Matijevic, Jacob R.; Reid, Lisa K.; Pavlics, Ferenc

    1999-01-01

    Most of the soil-like materials at the Pathfinder landing site behave like moderately dense soils on Earth with friction angles near 34°-39° and are called cloddy deposits. Cloddy deposits appear to be poorly sorted with dust-sized to granule-sized mineral or rock grains; they may contain pebbles, small rock fragments, and clods. Thin deposits of porous, compressible drifts with friction angles near 26°-28° are also present. Drifts are fine grained. Cohesions of both types of deposits are small. There may be indurated soil-like deposits and/or coated or crusted rocks. Cloddy deposits may be fluvial sediments of the Ares-Tiu floods, but other origins, such as ejecta from nearby impact craters, should be considered. Drifts are probably dusts that settled from the Martian atmosphere. Remote-sensing signatures of the deposits inferred from rover observations are consistent with those observed from orbit and Earth.

  18. Bayesian statistics for the calibration of the LISA Pathfinder experiment

    NASA Astrophysics Data System (ADS)

    Armano, M.; Audley, H.; Auger, G.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Brandt, N.; Bursi, A.; Caleno, M.; Cavalleri, A.; Cesarini, A.; Cruise, M.; Danzmann, K.; Diepholz, I.; Dolesi, R.; Dunbar, N.; Ferraioli, L.; Ferroni, V.; Fitzsimons, E.; Freschi, M.; García Marirrodriga, C.; Gerndt, R.; Gesa, L.; Gibert, F.; Giardini, D.; Giusteri, R.; Grimani, C.; Harrison, I.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hueller, M.; Huesler, J.; Inchauspé, H.; Jennrich, O.; Jetzer, P.; Johlander, B.; Karnesis, N.; Kaune, B.; Korsakova, N.; Killow, C.; Lloro, I.; Maarschalkerweerd, R.; Madden, S.; Mance, D.; Martin, V.; Martin-Porqueras, F.; Mateos, I.; McNamara, P.; Mendes, J.; Mitchell, E.; Moroni, A.; Nofrarias, M.; Paczkowski, S.; Perreur-Lloyd, M.; Pivato, P.; Plagnol, E.; Prat, P.; Ragnit, U.; Ramos-Castro, J.; Reiche, J.; Romera Perez, J. A.; Robertson, D.; Rozemeijer, H.; Russano, G.; Sarra, P.; Schleicher, A.; Slutsky, J.; Sopuerta, C. F.; Sumner, T.; Texier, D.; Thorpe, J.; Trenkel, C.; Tu, H. B.; Vitale, S.; Wanner, G.; Ward, H.; Waschke, S.; Wass, P.; Wealthy, D.; Wen, S.; Weber, W.; Wittchen, A.; Zanoni, C.; Ziegler, T.; Zweifel, P.

    2015-05-01

    The main goal of LISA Pathfinder (LPF) mission is to estimate the acceleration noise models of the overall LISA Technology Package (LTP) experiment on-board. This will be of crucial importance for the future space-based Gravitational-Wave (GW) detectors, like eLISA. Here, we present the Bayesian analysis framework to process the planned system identification experiments designed for that purpose. In particular, we focus on the analysis strategies to predict the accuracy of the parameters that describe the system in all degrees of freedom. The data sets were generated during the latest operational simulations organised by the data analysis team and this work is part of the LTPDA Matlab toolbox.

  19. Prediction and Validation of Mars Pathfinder Hypersonic Aerodynamic Data Base

    NASA Technical Reports Server (NTRS)

    Gnoffo, Peter A.; Braun, Robert D.; Weilmuenster, K. James; Mitcheltree, Robert A.; Engelund, Walter C.; Powell, Richard W.

    1998-01-01

    Postflight analysis of the Mars Pathfinder hypersonic, continuum aerodynamic data base is presented. Measured data include accelerations along the body axis and axis normal directions. Comparisons of preflight simulation and measurements show good agreement. The prediction of two static instabilities associated with movement of the sonic line from the shoulder to the nose and back was confirmed by measured normal accelerations. Reconstruction of atmospheric density during entry has an uncertainty directly proportional to the uncertainty in the predicted axial coefficient. The sensitivity of the moment coefficient to freestream density, kinetic models and center-of-gravity location are examined to provide additional consistency checks of the simulation with flight data. The atmospheric density as derived from axial coefficient and measured axial accelerations falls within the range required for sonic line shift and static stability transition as independently determined from normal accelerations.

  20. Classification of Mars Pathfinder Rock Surfaces Using Quantitative Morphologic Indices

    NASA Technical Reports Server (NTRS)

    Yingst, R. A.; Haldemann, A. F. C.; Lemmon, M. T.

    2003-01-01

    We have examined the morphology of rocks in two regions of the MPF landing site in terms of location, size and dimensions, sphericity sphericity and elongation, and have correlated this information with spectral data extracted from associated rock surfaces, with the goal of improving the likelihood of discerning between rock and rock surface types. We use four highly diverse Imager for Mars Pathfinder (IMP) images centered on Mini-Matterhorn and the Rock Garden because they are suited to demonstrate the wide morphologic variation of rocks at the site. A sampling of rocks was chosen at these locations that represented a range of shapes, textures and spectral signatures. In this initial analysis we focused upon the largest rocks that are situated in such a way as to allow easy viewing of most of the faces.

  1. State Space Modelling and Data Analysis Exercises in LISA Pathfinder

    NASA Astrophysics Data System (ADS)

    Nofrarias, M.; Antonucci, F.; Armano, M.; Audley, H.; Auger, G.; Benedetti, M.; Binetruy, P.; Bogenstahl, J.; Bortoluzzi, D.; Brandt, N.; Caleno, M.; Cavalleri, A.; Congedo, G.; Cruise, M.; Danzmann, K.; De Marchi, F.; Diaz-Aguilo, M.; Diepholz, I.; Dixon, G.; Dolesi, R.; Dunbar, N.; Fauste, J.; Ferraioli, L.; Ferroni, V.; Fichter, W.; Fitzsimons, E.; Freschi, M.; García Marirrodriga, C.; Gerndt, R.; Gesa, L.; Gibert, F.; Giardini, D.; Grimani, C.; Grynagier, A.; Guzmán, F.; Harrison, I.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hoyland, D.; Hueller, M.; Huesler, J.; Jennrich, O.; Jetzer, P.; Johlander, B.; Karnesis, N.; Korsakova, N.; Killow, C.; Llamas, X.; Lloro, I.; Lobo, A.; Maarschalkerweerd, R.; Madden, S.; Mance, D.; Martin, V.; Mateos, I.; McNamara, P.; Mendes, J.; Mitchell, E.; Nicolodi, D.; Perreur-Lloyd, M.; Plagnol, E.; Prat, P.; Ramos-Castro, J.; Reiche, J.; Romera Perez, J. A.; Robertson, D.; Rozemeijer, H.; Russano, G.; Schleicher, A.; Shaul, D.; Sopuerta, C. F.; Sumner, T. J.; Taylor, A.; Texier, D.; Trenkel, C.; Tu, H. B.; Vitale, S.; Wanner, G.; Ward, H.; Waschke, S.; Wass, P.; Wealthy, D.; Wen, S.; Weber, W.; Ziegler, T.; Zweifel, P.

    2013-01-01

    LISA Pathfinder is a mission planned by the European Space Agency (ESA) to test the key technologies that will allow the detection of gravitational waves in space. The instrument on-board, the LISA Technology package, will undergo an exhaustive campaign of calibrations and noise characterisation campaigns in order to fully describe the noise model. Data analysis plays an important role in the mission and for that reason the data analysis team has been developing a toolbox which contains all the functionality required during operations. In this contribution we give an overview of recent activities, focusing on the improvements in the modelling of the instrument and in the data analysis campaigns performed both with real and simulated data.

  2. Acquiring multiple stars with the LINC-NIRVANA Pathfinder

    NASA Astrophysics Data System (ADS)

    Conrad, Albert R.; Arcidiacono, Carmelo; Baumeister, Harald; Bergomi, Maria; Bertram, Thomas; Berwein, Jürgen; Briegel, Florian; Farinato, Jacopo; Herbst, Tom; Hofferbert, Ralph; Kittmann, Frank; Kürster, Martin; Kopon, Derek; Marafatto, Luca; Norris, Mark; Ragazzoni, Roberto; Viotto, Valentina

    2014-08-01

    The LINC-NIRVANA Pathfinder1 (LN-PF), a ground-layer adaptive optics (AO) system recently commissioned at the Large Binocular Telescope (LBT), is one of 4 sensors that provide AO corrected images to the full LINC-NIRVANA instrument. With first light having taken place on November 17, 2013,2, 3 the core goals for the LN-PF have been accomplished. In this report, we look forward to one of the LN-PF extended goals. In particular, we review the acquisition mechanism required to place each of several star probes on its corresponding star in the target asterism. For emerging AO systems in general, co-addition of light from multiple stars stands as one of several methods being pursued to boost sky coverage. With 12 probes patrolling a large field of view (an annulus 6-arcminutes in diameter), the LN-PF will provide a valuable testbed to verify this method.

  3. Wheel Abrasion Experiment Metals Selection for Mars Pathfinder Mission

    NASA Technical Reports Server (NTRS)

    Hepp, Aloysius F.; Fatemi, Navid S.; Wilt, David M.; Ferguson, Dale C.; Hoffman, Richard; Hill, Maria M.; Kaloyeros, Alain E.

    1996-01-01

    A series of metals was examined for suitability for the Wheel Abrasion Experiment, one of ten microrover experiments of the Mars Pathfinder Mission. The seven candidate metals were: Ag, Al, Au, Cu, Ni, Pt, and W. Thin films of candidate metals from 0.1 to 1.0 micrometer thick were deposited on black anodized aluminum coupons by e-beam and resistive evaporation and chemical vapor deposition. Optical, corrosion, abrasion, and adhesion criteria were used to select Al, Ni, and Pt. A description is given of the deposition and testing of thin films, followed by a presentation of experimental data and a brief discussion of follow-on testing and flight qualification.

  4. Techniques for identifying dust devils in mars pathfinder images

    USGS Publications Warehouse

    Metzger, S.M.; Carr, J.R.; Johnson, J.R.; Parker, T.J.; Lemmon, M.T.

    2000-01-01

    Image processing methods used to identify and enhance dust devil features imaged by IMP (Imager for Mars Pathfinder) are reviewed. Spectral differences, visible red minus visible blue, were used for initial dust devil searches, driven by the observation that Martian dust has high red and low blue reflectance. The Martian sky proved to be more heavily dust-laden than pre-Pathfinder predictions, based on analysis of images from the Hubble Space Telescope. As a result, these initial spectral difference methods failed to contrast dust devils with background dust haze. Imager artifacts (dust motes on the camera lens, flat-field effects caused by imperfections in the CCD, and projection onto a flat sensor plane by a convex lens) further impeded the ability to resolve subtle dust devil features. Consequently, reference images containing sky with a minimal horizon were first subtracted from each spectral filter image to remove camera artifacts and reduce the background dust haze signal. Once the sky-flat preprocessing step was completed, the red-minus-blue spectral difference scheme was attempted again. Dust devils then were successfully identified as bright plumes. False-color ratios using calibrated IMP images were found useful for visualizing dust plumes, verifying initial discoveries as vortex-like features. Enhancement of monochromatic (especially blue filter) images revealed dust devils as silhouettes against brighter background sky. Experiments with principal components transformation identified dust devils in raw, uncalibrated IMP images and further showed relative movement of dust devils across the Martian surface. A variety of methods therefore served qualitative and quantitative goals for dust plume identification and analysis in an environment where such features are obscure.

  5. James Webb Space Telescope (JWST) Optical Telescope Element (OTE) Pathfinder status and plans

    NASA Astrophysics Data System (ADS)

    Feinberg, Lee D.; Keski-Kuha, Ritva; Atkinson, Charlie; Booth, Andrew; Whitman, Tony

    2014-08-01

    A JWST OTE Pathfinder telescope that includes two spare primary mirror segments, a spare secondary mirror, and a large composite structure with a deployed secondary support structure is in the assembly stage and will be fully completed this year. This Pathfinder will check out key steps in the ambient mirror integration process and also be used at the Johnson Space Center (JSC) to check out the optical Ground Support Equipment (GSE) and associated procedures that will be used to test the full JWST telescope and instruments at JSC. This paper will summarize the Pathfinder integration and testing flow, the critical Ground Support Equipment it will test and the key tests planned with the Pathfinder.

  6. Processing and Analysis of Mars Pathfinder Science Data at JPL's Science Data Processing Section

    NASA Technical Reports Server (NTRS)

    LaVoie, S.; Green, W.; Runkle, A.; Alexander, D.; Andres, P.; DeJong, E.; Duxbury, E.; Freda, D.; Gorjian, Z.; Hall, J.; Hartman, F.; Levoe, S.; Lorre, J.; McAuley, J.; Suzuki, S.; Woncik, P.; Wright, J.

    1998-01-01

    The Mars Pathfinder mission required new capabilities and adaptation of existing capabilities in order to support science analysis and flight operations requirements imposed by the in-situ nature of the mission.

  7. Old Desert Varnish-like Coatings and Young Breccias at the Mars Pathfinder Landing Site

    NASA Technical Reports Server (NTRS)

    Murchie, S.; Barnouin-Jha, O.; Barnouin-Jha, K.; Bishop, J.; Johnson, J.; McSween, H.; Morris, R.

    2004-01-01

    Many rocks at the Mars Pathfinder landing site exhibit evidence for desert varnish-like coatings that formed during an early, moist climate. Later eolian erosion partly stripped the coatings. Rocks excavated subsequently have shapes consistent with breccias or conglomerates.

  8. Coral reef community composition in the context of disturbance history on the Great Barrier Reef, Australia.

    PubMed

    Graham, Nicholas A J; Chong-Seng, Karen M; Huchery, Cindy; Januchowski-Hartley, Fraser A; Nash, Kirsty L

    2014-01-01

    Much research on coral reefs has documented differential declines in coral and associated organisms. In order to contextualise this general degradation, research on community composition is necessary in the context of varied disturbance histories and the biological processes and physical features thought to retard or promote recovery. We conducted a spatial assessment of coral reef communities across five reefs of the central Great Barrier Reef, Australia, with known disturbance histories, and assessed patterns of coral cover and community composition related to a range of other variables thought to be important for reef dynamics. Two of the reefs had not been extensively disturbed for at least 15 years prior to the surveys. Three of the reefs had been severely impacted by crown-of-thorns starfish outbreaks and coral bleaching approximately a decade before the surveys, from which only one of them was showing signs of recovery based on independent surveys. We incorporated wave exposure (sheltered and exposed) and reef zone (slope, crest and flat) into our design, providing a comprehensive assessment of the spatial patterns in community composition on these reefs. Categorising corals into life history groupings, we document major coral community differences in the unrecovered reefs, compared to the composition and covers found on the undisturbed reefs. The recovered reef, despite having similar coral cover, had a different community composition from the undisturbed reefs, which may indicate slow successional processes, or a different natural community dominance pattern due to hydrology and other oceanographic factors. The variables that best correlated with patterns in the coral community among sites included the density of juvenile corals, herbivore fish biomass, fish species richness and the cover of macroalgae. Given increasing impacts to the Great Barrier Reef, efforts to mitigate local stressors will be imperative to encouraging coral communities to persist into the future. PMID:24983747

  9. Dynamic Stability of Coral Reefs on the West Australian Coast

    PubMed Central

    Speed, Conrad W.; Babcock, Russ C.; Bancroft, Kevin P.; Beckley, Lynnath E.; Bellchambers, Lynda M.; Depczynski, Martial; Field, Stuart N.; Friedman, Kim J.; Gilmour, James P.; Hobbs, Jean-Paul A.; Kobryn, Halina T.; Moore, James A. Y.; Nutt, Christopher D.; Shedrawi, George; Thomson, Damian P.; Wilson, Shaun K.

    2013-01-01

    Monitoring changes in coral cover and composition through space and time can provide insights to reef health and assist the focus of management and conservation efforts. We used a meta-analytical approach to assess coral cover data across latitudes 10–35°S along the west Australian coast, including 25 years of data from the Ningaloo region. Current estimates of coral cover ranged between 3 and 44% in coral habitats. Coral communities in the northern regions were dominated by corals from the families Acroporidae and Poritidae, which became less common at higher latitudes. At Ningaloo Reef coral cover has remained relatively stable through time (?28%), although north-eastern and southern areas have experienced significant declines in overall cover. These declines are likely related to periodic disturbances such as cyclones and thermal anomalies, which were particularly noticeable around 1998/1999 and 2010/2011. Linear mixed effects models (LME) suggest latitude explains 10% of the deviance in coral cover through time at Ningaloo. Acroporidae has decreased in abundance relative to other common families at Ningaloo in the south, which might be related to persistence of more thermally and mechanically tolerant families. We identify regions where quantitative time-series data on coral cover and composition are lacking, particularly in north-western Australia. Standardising routine monitoring methods used by management and research agencies at these, and other locations, would allow a more robust assessment of coral condition and a better basis for conservation of coral reefs. PMID:23922829

  10. Mars Pathfinder landing site assessment with Goldstone delay-Doppler and CW radar experiments

    Microsoft Academic Search

    A. F. C. Haldemann; D. L. Mitchell; R. F. Jurgens; M. A. Slade; D. O. Muhleman

    1997-01-01

    We present the results of 3.5-cm delay-Doppler and Doppler-only (continuous wave or CW) radar experiments to assess three potential Mars Pathfinder landing sites: Ares Vallis, Tritonis Lacus, and northwest (NW) Isidis. The regional relief at all of the landing sites is appropriate for a Pathfinder landing sequence: east-west slopes do not exceed 3 ø at any of the sites. We

  11. Sandstone Strata in Capitol Reef National Park

    USGS Multimedia Gallery

    A detail view of some sandstone strata within Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  12. Along-Track Reef Imaging System (ATRIS)

    USGS Publications Warehouse

    Brock, John; Zawada, Dave

    2006-01-01

    "Along-Track Reef Imaging System (ATRIS)" describes the U.S. Geological Survey's Along-Track Reef Imaging System, a boat-based sensor package for rapidly mapping shallow water benthic environments. ATRIS acquires high resolution, color digital images that are accurately geo-located in real-time.

  13. Ancient reef ecosystem expansion and collapse

    Microsoft Academic Search

    P. Copper

    1994-01-01

    Platform carbonate and, particularly, reef ecosystem development (with reefs representing the acme of carbonate platform growth) were highly cyclical in early to mid Paleozoic time, especially in relation to known or postulated times of global warming or cooling. These cycles do not appear to correspond to postulated 26 Ma rhythms seen in diversity patterns, nor were they regular. There were

  14. Artificial Reefs--A Coastal Classroom Project.

    ERIC Educational Resources Information Center

    Dindo, John J.

    1986-01-01

    Discusses the construction of artificial reefs for such uses as commercial fishing and recreational boating. Describes a class project in which students construct a small artificial reef and observe the changes over time in terms of temperature, salinity, flora and fauna. (TW)

  15. Reefs and Learning: Education Evaluation Techniques

    ERIC Educational Resources Information Center

    Stepath, Carl M.

    2006-01-01

    Marine education research designs are discussed, and student learning outcomes while monitoring a coral reef is evaluated. Changes in environmental knowledge and attitudes, ecological intention to act, and direct reef experience were investigated. Differences between student pre-test and the post-test responses were observed, and analysis is…

  16. Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve

    NSDL National Science Digital Library

    Describes the unique Northwestern Hawaiian Islands (NWHI) Ecosystem Reserve. Provides resources focused on NWHI coral reef ecosystems, and introductions to reef research, management and protection activities. Educational outreach includes: teacher workshops; student activities, and a Discovery Center in Hilo, Hawaii that features exhibits and activities for schools and the public.

  17. Subtropical Biotic Fringing Reefs as Ecological Laboratories.

    ERIC Educational Resources Information Center

    Hunt, Jeffrey W.

    1980-01-01

    Describes a 16-week course in marine biology involving a class-coordinated investigation of a subtropical biotic fringing reef of Hawaii. Describes in detail the development of preliminary hypotheses regarding general cause-effect relationships on the reef, and the exploration of specific areas, such as chemical or physical factors. (CS)

  18. Preliminary legal considerations in developing artificial reefs

    Microsoft Academic Search

    John L. Seymour

    1975-01-01

    Artificial reefs have been shown to be effective for attracting large concentrations of fish to distinct and readily located sites where fishermen are able to increase catches with reduced effort. These man?made reefs, constructed of materials ranging from sunken surplus Liberty ships to worn out tires, may become effective tools in fisheries and coastal zone management programs. There are numerous

  19. A Global Estimate of the Number of Coral Reef Fishers.

    PubMed

    Teh, Louise S L; Teh, Lydia C L; Sumaila, U Rashid

    2013-01-01

    Overfishing threatens coral reefs worldwide, yet there is no reliable estimate on the number of reef fishers globally. We address this data gap by quantifying the number of reef fishers on a global scale, using two approaches - the first estimates reef fishers as a proportion of the total number of marine fishers in a country, based on the ratio of reef-related to total marine fish landed values. The second estimates reef fishers as a function of coral reef area, rural coastal population, and fishing pressure. In total, we find that there are 6 million reef fishers in 99 reef countries and territories worldwide, of which at least 25% are reef gleaners. Our estimates are an improvement over most existing fisher population statistics, which tend to omit accounting for gleaners and reef fishers. Our results suggest that slightly over a quarter of the world's small-scale fishers fish on coral reefs, and half of all coral reef fishers are in Southeast Asia. Coral reefs evidently support the socio-economic well-being of numerous coastal communities. By quantifying the number of people who are employed as reef fishers, we provide decision-makers with an important input into planning for sustainable coral reef fisheries at the appropriate scale. PMID:23840327

  20. A Global Estimate of the Number of Coral Reef Fishers

    PubMed Central

    Teh, Louise S. L.; Teh, Lydia C. L.; Sumaila, U. Rashid

    2013-01-01

    Overfishing threatens coral reefs worldwide, yet there is no reliable estimate on the number of reef fishers globally. We address this data gap by quantifying the number of reef fishers on a global scale, using two approaches - the first estimates reef fishers as a proportion of the total number of marine fishers in a country, based on the ratio of reef-related to total marine fish landed values. The second estimates reef fishers as a function of coral reef area, rural coastal population, and fishing pressure. In total, we find that there are 6 million reef fishers in 99 reef countries and territories worldwide, of which at least 25% are reef gleaners. Our estimates are an improvement over most existing fisher population statistics, which tend to omit accounting for gleaners and reef fishers. Our results suggest that slightly over a quarter of the world’s small-scale fishers fish on coral reefs, and half of all coral reef fishers are in Southeast Asia. Coral reefs evidently support the socio-economic well-being of numerous coastal communities. By quantifying the number of people who are employed as reef fishers, we provide decision-makers with an important input into planning for sustainable coral reef fisheries at the appropriate scale. PMID:23840327

  1. Validation of the Version 1 NOAA/NASA Pathfinder Sea Surface Temperature Data Set

    NASA Technical Reports Server (NTRS)

    Smith, Elizabeth A.

    1998-01-01

    A high-resolution, global satellite-derived sea surface temperature (SST) data set called Pathfinder, from the Advanced Very High Resolution Radiometer (AVHRR) aboard the NOAA Polar Orbiters, is available from the Jet Propulsion Laboratory Physical Oceanography Distributed Active Archive Center (JPL PO.DAAC). Suitable for research as well as education, the Pathfinder SST data set is a result of a collaboration between the National Oceanographic and Atmospheric Administration (NOAA), the National Aeronautics and Space Administration (NASA) and investigators at several universities. NOAA and NASA are the sponsors of the Pathfinder Program, which takes advantage of currently archived Earth science data from satellites. Where necessary, satellite sensors have been intercalibrated, algorithms improved and processing procedures revised, in order to produce long time-series, global measurements of ocean, land and atmospheric properties necessary for climate research. Many Pathfinder data sets are available to researchers now, nearly a decade before the first launch of NASA's Earth Observing System (EOS). The lessons learned from the Pathfinder programs will facilitate the processing and management of terabytes of data from EOS. The Oceans component of Pathfinder has undertaken to reprocess all Global Area Coverage (GAC) data acquired by the 5-channel AVHRRs since 1981. The resultant data products are consistent and stably calibrated [Rao, 1993a, Rao, 1993b, Brown et al., 1993], Earth-gridded SST fields at a variety of spatial and temporal resolutions.

  2. A large coral reef in the Pennsylvanian of Ziyun County, Guizhou (South China): The substrate and initial colonization environment of reef-building corals

    Microsoft Academic Search

    Yong-Li Zhang; En-Pu Gong; Mark A. Wilson; Chang-Qing Guan; Bao-Liang Sun

    2010-01-01

    Studies of Pennsylvanian reefs are mainly focused on algal reefs; research on non-algal framework reefs is relatively uncommon. The Bianping coral reef is the largest Pennsylvanian framework reef in China. The main builders of the reef were the rugose corals Fomitchevella. Some paleontological phenomena indicate that the coral Fomitchevella colonized a hard substrate which included encrusting tubular organisms, microbial carbonate,

  3. National Center for Caribbean Coral Reef Research

    NSDL National Science Digital Library

    A number of research centers are concerned with the state of the world's coral reefs, and the National Center for Caribbean Coral Reef Research (NCORE) is one such center of scholarly excellence. Located at the University of Miami, NCORE is primarily concerned with "the analysis and predication of coral reef resilience". On their site, visitors can learn about some of their primary research initiatives, such as their work on the Florida reef tract and on tracking the effects of climate change on the reef communities. The general public will also find their digital map series quite useful as well. In this section, users can examine a number of complex digital maps and images that provide information about the state of coral cover around Puerto Rico, South Florida, and the Bahamas.

  4. Coral Reef Information System: Discover NOAA's Data

    NSDL National Science Digital Library

    Part of the National Oceanic and Atmospheric Administration's Coral Reef Information System (CoRIS), this Web site is "designed to be a single point of access to NOAA coral reef information and data products, especially those derived from NOAA's Coral Reef Initiative Program." With Discover NOAA's Data, users can access information by a text search of metadata records, or by a spatial search using an Arc IMS application. The two approaches share many of the same data sets. With the text search, users may search NOAA coral reef information by title, author, keyword, etc. The map program includes "over 19,000 aerial photos, 400 preview navigational charts, tide stations, paleoclimatological studies, photo mosaics, coral reef monitoring, bleaching reports, and more." The site provides numerous help features for both search methods.

  5. Satellite tracking of Harbour Seals on Horns Reef Use of the Horns Reef wind farm area and the North Sea

    E-print Network

    Satellite tracking of Harbour Seals on Horns Reef Use of the Horns Reef wind farm area. : Harbour seals on Horns Reef. Summary Ten harbour seals (Phoca vitulina) caught on the Danish Wadden Sea Reef. Based on previous studies using VHF- transmitters, it was expected that the seals would spend

  6. Connectivity of reef fish between mangroves and coral reefs: Algorithms for the design of marine reserves at seascape scales

    Microsoft Academic Search

    Peter J. Mumby

    2005-01-01

    Many species of coral reef fish undertake ontogenetic migrations between seagrass beds, mangroves, and coral reefs. A recent study from the Caribbean found that the availability of mangrove nursery habitat had a striking impact on the community structure and bio- mass of reef fish in their adult, coral reef habitat. The biomass of several species more than doubled when the

  7. Geomorphology and sediment transport on a submerged back-reef sand apron: One Tree Reef, Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Harris, Daniel L.; Vila-Concejo, Ana; Webster, Jody M.

    2014-10-01

    Back-reef sand aprons are conspicuous and dynamic sedimentary features in coral reef systems. The development of these features influences the evolution and defines the maturity of coral reefs. However, the hydrodynamic processes that drive changes on sand aprons are poorly understood with only a few studies directly assessing sediment entrainment and transport. Current and wave conditions on a back-reef sand apron were measured during this study and a digital elevation model was developed through topographic and bathymetric surveying of the sand apron, reef flats and lagoon. The current and wave processes that may entrain and transport sediment were assessed using second order small amplitude (Stokes) wave theory and Shields equations. The morphodynamic interactions between current flow and geomorphology were also examined. The results showed that sediment transport occurs under modal hydrodynamic conditions with waves the main force entraining sediment rather than average currents. A morphodynamic relationship between current flow and geomorphology was also observed with current flow primarily towards the lagoon in shallow areas of the sand apron and deeper channel-like areas directing current off the sand apron towards the lagoon or the reef crest. These results show that the short-term mutual interaction of hydrodynamics and geomorphology in coral reefs can result in morphodynamic equilibrium.

  8. Wave transformation across coral reefs under changing sea levels

    NASA Astrophysics Data System (ADS)

    Harris, Daniel; Power, Hannah; Vila Conejo, Ana; Webster, Jody

    2015-04-01

    The transformation of swell waves from deep water across reef flats is the primary process regulating energy regimes in coral reef systems. Coral reefs are effective barriers removing up to 99% of wave energy during breaking and propagation across reef flats. Consequently back-reef environments are often considered low energy with only limited sediment transport and geomorphic change during modal conditions. Coral reefs, and specifically reef flats, therefore provide important protection to tropical coastlines from coastal erosion and recession. However, changes in sea level could lead to significant changes in the dissipation of swell wave energy in coral reef systems with wave heights dependent on the depth over the reef flat. This suggests that a rise in sea level would also lead to significantly higher energy conditions exacerbating the transgressive effects of sea level rise on tropical beaches and reef islands. This study examines the potential implications of different sea level scenarios on the transformation of waves across the windward reef flats of One Tree Reef, southern Great Barrier Reef. Waves were measured on the reef flats and back-reef sand apron of One Tree Reef. A one-dimensional wave model was calibrated and used to investigate wave processes on the reef flats under different mean sea level (MSL) scenarios (present MSL, +1 m MSL, and +2 m MSL). These scenarios represent both potential future sea level states and also the paleo sea level of the late Holocene in the southern Great Barrier Reef. Wave heights were shown to increase under sea level rise, with greater wave induced orbital velocities affecting the bed under higher sea levels. In general waves were more likely to entrain and transport sediment both on the reef flat and in the back reef environment under higher sea levels which has implications for not only forecasted climate change scenarios but also for interpreting geological changes during the late Holocene when sea levels were 1-2 m higher than present.

  9. A novel reef coral symbiosis

    NASA Astrophysics Data System (ADS)

    Pantos, O.; Bythell, J. C.

    2010-09-01

    Reef building corals form close associations with unicellular microalgae, fungi, bacteria and archaea, some of which are symbiotic and which together form the coral holobiont. Associations with multicellular eukaryotes such as polychaete worms, bivalves and sponges are not generally considered to be symbiotic as the host responds to their presence by forming physical barriers with an active growth edge in the exoskeleton isolating the invader and, at a subcellular level, activating innate immune responses such as melanin deposition. This study describes a novel symbiosis between a newly described hydrozoan ( Zanclea margaritae sp. nov.) and the reef building coral Acropora muricata (= A. formosa), with the hydrozoan hydrorhiza ramifying throughout the coral tissues with no evidence of isolation or activation of the immune systems of the host. The hydrorhiza lacks a perisarc, which is typical of symbiotic species of this and related genera, including species that associate with other cnidarians such as octocorals. The symbiosis was observed at all sites investigated from two distant locations on the Great Barrier Reef, Australia, and appears to be host species specific, being found only in A. muricata and in none of 30 other species investigated at these sites. Not all colonies of A. muricata host the hydrozoans and both the prevalence within the coral population (mean = 66%) and density of emergent hydrozoan hydranths on the surface of the coral (mean = 4.3 cm-2, but up to 52 cm-2) vary between sites. The form of the symbiosis in terms of the mutualism-parasitism continuum is not known, although the hydrozoan possesses large stenotele nematocysts, which may be important for defence from predators and protozoan pathogens. This finding expands the known A. muricata holobiont and the association must be taken into account in future when determining the corals’ abilities to defend against predators and withstand stress.

  10. The Reef Environmental Education Foundation

    NSDL National Science Digital Library

    2003-02-17

    The purpose of REEF is to educate and enlist divers in the conservation of marine habitats. The main focus of this site is the Fish Survey Project, in which volunteer scuba divers and snorkelers collect and report information on marine fish populations. The data is accessible through this website, and users can both contribute data they gather and generate reports from the database. A variety of reports can be created, including lists of all species found within a specific geographic area or the distribution of a fish species or family. There is an excellent explanation of how the data can be interpreted and what the parameters in the reports represent.

  11. Sediment and turbidity associated with offshore dredging increase coral disease prevalence on nearby reefs.

    PubMed

    Pollock, F Joseph; Lamb, Joleah B; Field, Stuart N; Heron, Scott F; Schaffelke, Britta; Shedrawi, George; Bourne, David G; Willis, Bette L

    2014-01-01

    In recent decades, coral reef ecosystems have declined to the extent that reefs are now threatened globally. While many water quality parameters have been proposed to contribute to reef declines, little evidence exists conclusively linking specific water quality parameters with increased disease prevalence in situ. Here we report evidence from in situ coral health surveys confirming that chronic exposure to dredging-associated sediment plumes significantly increase the prevalence of white syndromes, a devastating group of globally important coral diseases. Coral health surveys were conducted along a dredging-associated sediment plume gradient to assess the relationship between sedimentation, turbidity and coral health. Reefs exposed to the highest number of days under the sediment plume (296 to 347 days) had two-fold higher levels of disease, largely driven by a 2.5-fold increase in white syndromes, and a six-fold increase in other signs of compromised coral health relative to reefs with little or no plume exposure (0 to 9 days). Multivariate modeling and ordination incorporating sediment exposure level, coral community composition and cover, predation and multiple thermal stress indices provided further confirmation that sediment plume exposure level was the main driver of elevated disease and other compromised coral health indicators. This study provides the first evidence linking dredging-associated sedimentation and turbidity with elevated coral disease prevalence in situ. Our results may help to explain observed increases in global coral disease prevalence in recent decades and suggest that minimizing sedimentation and turbidity associated with coastal development will provide an important management tool for controlling coral disease epizootics. PMID:25029525

  12. Integrating structure-from-motion photogrammetry with geospatial software as a novel technique for quantifying 3D ecological characteristics of coral reefs

    PubMed Central

    Delparte, D; Gates, RD; Takabayashi, M

    2015-01-01

    The structural complexity of coral reefs plays a major role in the biodiversity, productivity, and overall functionality of reef ecosystems. Conventional metrics with 2-dimensional properties are inadequate for characterization of reef structural complexity. A 3-dimensional (3D) approach can better quantify topography, rugosity and other structural characteristics that play an important role in the ecology of coral reef communities. Structure-from-Motion (SfM) is an emerging low-cost photogrammetric method for high-resolution 3D topographic reconstruction. This study utilized SfM 3D reconstruction software tools to create textured mesh models of a reef at French Frigate Shoals, an atoll in the Northwestern Hawaiian Islands. The reconstructed orthophoto and digital elevation model were then integrated with geospatial software in order to quantify metrics pertaining to 3D complexity. The resulting data provided high-resolution physical properties of coral colonies that were then combined with live cover to accurately characterize the reef as a living structure. The 3D reconstruction of reef structure and complexity can be integrated with other physiological and ecological parameters in future research to develop reliable ecosystem models and improve capacity to monitor changes in the health and function of coral reef ecosystems.

  13. Integrating structure-from-motion photogrammetry with geospatial software as a novel technique for quantifying 3D ecological characteristics of coral reefs.

    PubMed

    Burns, Jhr; Delparte, D; Gates, R D; Takabayashi, M

    2015-01-01

    The structural complexity of coral reefs plays a major role in the biodiversity, productivity, and overall functionality of reef ecosystems. Conventional metrics with 2-dimensional properties are inadequate for characterization of reef structural complexity. A 3-dimensional (3D) approach can better quantify topography, rugosity and other structural characteristics that play an important role in the ecology of coral reef communities. Structure-from-Motion (SfM) is an emerging low-cost photogrammetric method for high-resolution 3D topographic reconstruction. This study utilized SfM 3D reconstruction software tools to create textured mesh models of a reef at French Frigate Shoals, an atoll in the Northwestern Hawaiian Islands. The reconstructed orthophoto and digital elevation model were then integrated with geospatial software in order to quantify metrics pertaining to 3D complexity. The resulting data provided high-resolution physical properties of coral colonies that were then combined with live cover to accurately characterize the reef as a living structure. The 3D reconstruction of reef structure and complexity can be integrated with other physiological and ecological parameters in future research to develop reliable ecosystem models and improve capacity to monitor changes in the health and function of coral reef ecosystems. PMID:26207190

  14. Coral Reef Adventure Fun Zone

    NSDL National Science Digital Library

    Science NetLinks (AAAS; )

    2007-04-29

    The Memory Game beginner is the best game for students of all ages to play unless there is a student who knows an unusual amount of information about coral reefs. In this case, that student can play the expert level where he/she will match the name or phrase with a picture.To begin, students should click on the GO! icon on the Memory Game and then again on the GO! icon on the pop-up screen. The beginner version requires students to match alike pictures. Students should click on the images to find the matching pairs. As they click on an image and then click on another, the previous image goes away if it's not a match.so students need to remember where they clicked on each image.Once students find a matching pair, they need to click on one image and then click on its matching image to keep the matching pair on the screen. Students should continue this process until all the images are found. On the bottom left of this screen there is a Move counter that keeps track of how many times students click on an image. If students want to try again to achieve a better score, then they can start the game over on a new screen. As noted below, there are other games that would be suitable for playing after students learn more about coral reefs.

  15. 76 FR 63904 - Proposed Information Collection; Comment Request; Coral Reef Conservation Program Administration

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-14

    ...Information Collection; Comment Request; Coral Reef Conservation Program Administration...SUPPLEMENTARY INFORMATION: I. Abstract The Coral Reef Conservation Act of 2000 (Act) was...enacted to provide a framework for conserving coral reefs. The Coral Reef Conservation...

  16. Mapping water quality and substrate cover in optically complex coastal and reef waters: an integrated approach.

    PubMed

    Phinn, S R; Dekker, A G; Brando, V E; Roelfsema, C M

    2005-01-01

    Sustainable management of coastal and coral reef environments requires regular collection of accurate information on recognized ecosystem health indicators. Satellite image data and derived maps of water column and substrate biophysical properties provide an opportunity to develop baseline mapping and monitoring programs for coastal and coral reef ecosystem health indicators. A significant challenge for satellite image data in coastal and coral reef water bodies is the mixture of both clear and turbid waters. A new approach is presented in this paper to enable production of water quality and substrate cover type maps, linked to a field based coastal ecosystem health indicator monitoring program, for use in turbid to clear coastal and coral reef waters. An optimized optical domain method was applied to map selected water quality (Secchi depth, Kd PAR, tripton, CDOM) and substrate cover type (seagrass, algae, sand) parameters. The approach is demonstrated using commercially available Landsat 7 Enhanced Thematic Mapper image data over a coastal embayment exhibiting the range of substrate cover types and water quality conditions commonly found in sub-tropical and tropical coastal environments. Spatially extensive and quantitative maps of selected water quality and substrate cover parameters were produced for the study site. These map products were refined by interactions with management agencies to suit the information requirements of their monitoring and management programs. PMID:15757744

  17. Demography of the ecosystem engineer Crassostrea gigas, related to vertical reef accretion and reef persistence

    NASA Astrophysics Data System (ADS)

    Walles, Brenda; Mann, Roger; Ysebaert, Tom; Troost, Karin; Herman, Peter M. J.; Smaal, Aad C.

    2015-03-01

    Marine species characterized as structure building, autogenic ecosystem engineers are recognized worldwide as potential tools for coastal adaptation efforts in the face of sea level rise. Successful employment of ecosystem engineers in coastal protection largely depends on long-term persistence of their structure, which is in turn dependent on the population dynamics of the individual species. Oysters, such as the Pacific oyster (Crassostrea gigas), are recognized as ecosystem engineers with potential for use in coastal protection. Persistence of oyster reefs is strongly determined by recruitment and shell production (growth), processes facilitated by gregarious settlement on extant shell substrate. Although the Pacific oyster has been introduced world-wide, and has formed dense reefs in the receiving coastal waters, the population biology of live oysters and the quantitative mechanisms maintaining these reefs has rarely been studied, hence the aim of the present work. This study had two objectives: (1) to describe the demographics of extant C. gigas reefs, and (2) to estimate vertical reef accretion rates and carbonate production in these oyster reefs. Three long-living oyster reefs (>30 years old), which have not been exploited since their first occurrence, were examined in the Oosterschelde estuary in the Netherlands. A positive reef accretion rate (7.0-16.9 mm year-1 shell material) was observed, consistent with self-maintenance and persistent structure. We provide a framework to predict reef accretion and population persistence under varying recruitment, growth and mortality scenarios.

  18. Model Checking Real Time Java Using Java PathFinder

    NASA Technical Reports Server (NTRS)

    Lindstrom, Gary; Mehlitz, Peter C.; Visser, Willem

    2005-01-01

    The Real Time Specification for Java (RTSJ) is an augmentation of Java for real time applications of various degrees of hardness. The central features of RTSJ are real time threads; user defined schedulers; asynchronous events, handlers, and control transfers; a priority inheritance based default scheduler; non-heap memory areas such as immortal and scoped, and non-heap real time threads whose execution is not impeded by garbage collection. The Robust Software Systems group at NASA Ames Research Center has JAVA PATHFINDER (JPF) under development, a Java model checker. JPF at its core is a state exploring JVM which can examine alternative paths in a Java program (e.g., via backtracking) by trying all nondeterministic choices, including thread scheduling order. This paper describes our implementation of an RTSJ profile (subset) in JPF, including requirements, design decisions, and current implementation status. Two examples are analyzed: jobs on a multiprogramming operating system, and a complex resource contention example involving autonomous vehicles crossing an intersection. The utility of JPF in finding logic and timing errors is illustrated, and the remaining challenges in supporting all of RTSJ are assessed.

  19. PathFinder Science: Keeping an Eye on Ozone

    NSDL National Science Digital Library

    This site offers information and research projects that engage students in learning about ground level ozone. As part of the Pathfinder Science Collaborative Research program, students conduct scientific research on real-world topics to understand the process of science. They then submit their data so that other students and scientists around the world gain a better understanding of the issues and drive further research. Other topics include monitoring monarch butterflies, lichens, and greenhouse gases. In this forum, students determine the level of tropospheric ozone in their area and the impact on organisms in the environment, such as the milkweed plant. Background information, instructions for making ozone testing paper, and a protocol for measuring the impact of ozone on milkweed plant are provided. After collecting data, students submit it electronically and then access other students' data to develop and answer further research questions. The site also offers information on formulating questions, research methods, and data analysis along with the process and values that underlie scientific research.

  20. Antenna Deployment for a Pathfinder Lunar Radio Observatory

    NASA Technical Reports Server (NTRS)

    MacDowall, Robert J.; Minetto, F. A.; Lazio, T. W.; Jones, D. L.; Kasper, J. C.; Burns, J. O.; Stewart, K. P.; Weiler, K. W.

    2012-01-01

    A first step in the development of a large radio observatory on the moon for cosmological or other astrophysical and planetary goals is to deploy a few antennas as a pathfinder mission. In this presentation, we describe a mechanism being developed to deploy such antennas from a small craft, such as a Google Lunar X-prize lander. The antenna concept is to deposit antennas and leads on a polyimide film, such as Kapton, and to unroll the film on the lunar surface. The deployment technique utilized is to launch an anchor which pulls a double line from a reel at the spacecraft. Subsequently, the anchor is set by catching on the surface or collecting sufficient regolith. A motor then pulls in one end of the line, pulling the film off of its roller onto the lunar surface. Detection of a low frequency cutoff of the galactic radio background or of solar radio bursts by such a system would determine the maximum lunar ionospheric density at the time of measurement. The current design and testing, including videos of the deployment, will be presented. These activities are funded in part by the NASA Lunar Science Institute as an activity of the Lunar University Network for Astrophysical Research (LUNAR) consortium. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  1. Trajectory Based Heating and Ablation Calculations for MESUR Pathfinder Aeroshell

    NASA Technical Reports Server (NTRS)

    Chen, Y. K.; Henline, W. D.; Tauber, M. E.; Arnold, James O. (Technical Monitor)

    1994-01-01

    Based on the geometry of Mars Environment Survey (MESUR) Pathfinder aeroshell and an estimated Mars entry trajectory, two-dimensional axisymmetric time dependent calculations have been obtained using GIANTS (Gauss-Siedel Implicit Aerothermodynamic Navier-Stokes code with Thermochemical Surface Conditions) code and CMA (Charring Material Thermal Response and Ablation) Program for heating analysis and heat shield material sizing. These two codes are interfaced using a loosely coupled technique. The flowfield and convective heat transfer coefficients are computed by the GIANTS code with a species balance condition for an ablating surface, and the time dependent in-depth conduction with surface blowing is simulated by the CMA code with a complete surface energy balance condition. In this study, SLA-561V has been selected as heat shield material. The solutions, including the minimum heat shield thicknesses over aeroshell forebody, pyrolysis gas blowing rates, surface heat fluxes and temperature distributions, flowfield, and in-depth temperature history of SLA-561V, are presented and discussed in detail.

  2. Polar Geophysics Products Derived from AVHRR: The "AVHRR Polar Pathfinder

    NASA Technical Reports Server (NTRS)

    Maslanik, James; Fowler, Charles; Scambos, Theodore

    1999-01-01

    This NOAA/NASA Pathfinder effort was established to locate, acquire, and process Advanced Very High Resolution Radiometer (AVHRR) imagery into geo-located and calibrated radiances, cloud masks, surface clear-sky broadband albedo, clear-sky skin temperatures, satellite viewing times, and viewing and solar geometry for the, high-latitude portions of the northern and southern hemispheres (all area north of 48N and south of 53S). AVHRR GAC data for August 1981 - July 1998 were acquired, with some gaps remaining, and processed into twice-daily 5-km grids, with some products also provided at 25-km resolution. AVHRR LAC data for 3.5 years of coverage in the northern hemisphere and 2.75 years of coverage in the southern hemisphere were processed into 1.25-km grids for the same suite of products. The resulting data sets are presently being transferred to the National Snow and Ice Data Center (NSIDC) for archiving and distribution. Using these data, researchers now have at their disposal an extensive AVHRR data set for investigations of high-latitude processes. In addition, the data lend themselves to development and testing of algorithms. The products are particularly relevant for climate research and algorithm development as applied to relatively long time periods and large areas.

  3. Slope Morphology of Twin Peaks, Mars Pathfinder Landing Site

    NASA Astrophysics Data System (ADS)

    Hobbs, Steven; Paine, Colin; Clarke, Jon; Caprarelli, Graziella

    2010-05-01

    Development of slope form over time has long been a concern of geomorphologists, although recently this concern has been moved to slope processes rather than form. There are two basic approaches. The first is theoretical, involving modeling of different types and rates of processes, and calculation of results in terms of slope evolution over time. Comparisons with real-life slopes can follow this approach [1], [2]. The second, inductive, approach involves field measurements to test ideas about slope evolution starting from the assumption that observed slopes represent different stages of an essentially similar evolution [3]. Space is substituted for time, and a number of slopes, assumed to be of increasing age, are measured and placed in an evolutionary sequence (e.g. [4], [5], [6]). [5] showed that slope angles are modally distributed, with the modal angles controlled by the materials (regolith) of which the slopes are formed, and by the processes operating on them. Data can be obtained directly from field work or from digital elevation models (DEM) derived from remote sensing investigations [7]. DEMs are particularly useful to study inaccessible planets, such as Mars, where on site observations are restricted to only a few landing sites. Here we present a study of slopes on the Twin Peaks, two small hills located 780 m north and 910 m south of the Mars Pathfinder landing site at the mouth of the Ares and Tiu flood channels. The presence of streamlined hills, jumbled surfaces and conglomerates suggested the region was modified by massive flooding 1.8 - 3.5 billion years ago [8], [9]. The streamlined forms and terraces of the Twin Peaks were taken to indicate catastrophic flood conditions that were believed to be prevalent in the area [8]. It was also suggested that the northernmost peak was topped by floodwater, causing its flatter appearance. Other researchers postulated alternative geomorphological origins for the features observed at the Pathfinder landing site. Processes such as ice flow or deposition were proposed as being the principal cause of most of observed features, by analogy with similar features observed on Earth [10]. Here we propose that the slopes on the Twin Peaks may provide an indication of the processes that shaped them after they were formed. This work shows the results of a detailed morphometric analysis of slopes on the southernmost peak, conducted to gain a greater understanding of past and present slope processes at work at the Pathfinder landing site. The southern Twin Peak is a conical hill rising 38 m above the local terrain. A portion of the Pathfinder super panorama was used to analyse the hill-slope morphology. The camera horizon was used as a baseline and all slope angles were measured from this. The hill comprises four separate regions including the top of the hill, which is convex in shape. The convex nature of the hilltop is a common if not ubiquitous feature of hills regardless of their origin. It is related to the creep processes that frequently dominate the tops of hill slopes. In this case it was probably caused by heating and cooling during the Martian diurnal cycle, by the action of soil water, or a combination of both. All slope sections were observed to be similar in length. The slopes nearest the hill top measure 21? and 22.5? respectively on the north and south sides of the Southern Twin Peak. Mid way down the hill the next sequence of slopes have north and south angles of 9? and 15? respectively. Shallow end-slopes measure 4? and 5? north and south respectively. Similarity of slope angles and lengths indicates symmetry, suggesting that the rocks are the same all around the hill. Our analysis suggests that slope angles are controlled by a combination of the materials of which they are formed and the processes that are operating on them. Their primarily symmetrical outlook indicates no structural control, suggesting that the hill is formed by flat-lying or massive homogeneous rocks. This being the case, slope morphology results from shallow processes related to mass was

  4. Multiple Sun-Earth Saddle Point flybys for LISA Pathfinder

    NASA Astrophysics Data System (ADS)

    Fabacher, Emilien; Kemble, Stephen; Trenkel, Christian; Dunbar, Neil

    2013-07-01

    LISA Pathfinder is an ESA mission due to be launched in the next two years. The gravity gradiometer onboard has the sensitivity required to test predictions by gravitational theories proposed as alternatives to Dark Matter such as TeVeS. Within the Solar System measurable effects are predicted only in the vicinity of gravitational saddle points (SP). For this reason it has been proposed to fly LPF by the Earth-Sun SP, at some 259,000 km from Earth. This could be done in an extension to the nominal mission which uses a Lissajous orbit about the Earth-Sun L1 point. The responsibility for LPF mission design lies with ESA/ESOC, who have designed the transfer trajectories, orbits about L1, and station keeping strategies. This article describes an analysis performed by Astrium to support a suggestion for a possible mission extension to a saddle point crossing. With only very limited fuel availability, reaching the saddle point is a significant challenge. In this article, we present recent advances in the work on trajectory design. It is demonstrated that reaching the SP is feasible once the LPF mission is completed. Furthermore, in a significant enhancement, it is demonstrated that trajectories including more than one SP flyby are possible, thus improving the science return for this proposed mission extension.

  5. Metabolic PathFinding: inferring relevant pathways in biochemical networks.

    PubMed

    Croes, Didier; Couche, Fabian; Wodak, Shoshana J; van Helden, Jacques

    2005-07-01

    Our knowledge of metabolism can be represented as a network comprising several thousands of nodes (compounds and reactions). Several groups applied graph theory to analyse the topological properties of this network and to infer metabolic pathways by path finding. This is, however, not straightforward, with a major problem caused by traversing irrelevant shortcuts through highly connected nodes, which correspond to pool metabolites and co-factors (e.g. H2O, NADP and H+). In this study, we present a web server implementing two simple approaches, which circumvent this problem, thereby improving the relevance of the inferred pathways. In the simplest approach, the shortest path is computed, while filtering out the selection of highly connected compounds. In the second approach, the shortest path is computed on the weighted metabolic graph where each compound is assigned a weight equal to its connectivity in the network. This approach significantly increases the accuracy of the inferred pathways, enabling the correct inference of relatively long pathways (e.g. with as many as eight intermediate reactions). Available options include the calculation of the k-shortest paths between two specified seed nodes (either compounds or reactions). Multiple requests can be submitted in a queue. Results are returned by email, in textual as well as graphical formats (available in http://www.scmbb.ulb.ac.be/pathfinding/). PMID:15980483

  6. CORAL DISEASE & HEALTH CONSORTIUM; PARTNERS FOR PRESERVATION

    EPA Science Inventory

    Presented at EMAP Symposium 2001: Coastal Monitoring Through Partnerships, 24-27 April 2001, Pensacola Beach, FL. The Coral Disease and Health Consortium (CDHC) was one recommendation to the U.S. Coral Reef Task Force (CRTF), to conserve the coral reef ecosystems of the U...

  7. Oysters and Oyster Reef Communities in Florida.

    ERIC Educational Resources Information Center

    Knight, Jean; Bly, Joe

    1989-01-01

    The habitat, life history, feeding, classification, anatomy and pearl production of the American oyster (Crassostrea virginica) are presented. A list of other oyster reef inhabitants and predators is provided. Harvest and habitat loss are discussed. (CW)

  8. Quaternary coral reef refugia preserved fish diversity.

    PubMed

    Pellissier, Loïc; Leprieur, Fabien; Parravicini, Valeriano; Cowman, Peter F; Kulbicki, Michel; Litsios, Glenn; Olsen, Steffen M; Wisz, Mary S; Bellwood, David R; Mouillot, David

    2014-05-30

    The most prominent pattern in global marine biogeography is the biodiversity peak in the Indo-Australian Archipelago. Yet the processes that underpin this pattern are still actively debated. By reconstructing global marine paleoenvironments over the past 3 million years on the basis of sediment cores, we assessed the extent to which Quaternary climate fluctuations can explain global variation in current reef fish richness. Comparing global historical coral reef habitat availability with the present-day distribution of 6316 reef fish species, we find that distance from stable coral reef habitats during historical periods of habitat loss explains 62% of the variation in fish richness, outweighing present-day environmental factors. Our results highlight the importance of habitat persistence during periods of climate change for preserving marine biodiversity. PMID:24876495

  9. 40 CFR 230.44 - Coral reefs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...skeletal deposit, usually of calcareous or silicaceous materials, produced by the vital activities of anthozoan polyps or other invertebrate organisms present in growing portions of the reef. (b) Possible loss of values: The discharge of dredged or fill...

  10. EPA Field Manual for Coral Reef Assessments

    EPA Science Inventory

    The Water Quality Research Program (WQRP) supports development of coral reef biological criteria. Research is focused on developing methods and tools to support implementation of legally defensible biological standards for maintaining biological integrity, which is protected by ...

  11. Explore coral reefs around the world

    NSDL National Science Digital Library

    TERC

    This interactive map shows examples of coral reef locations in the Pacific, Caribbean, and Indian oceans. By clicking on a location, you can see the environmental conditions necessary for growth in terms of both ocean depth and sea surface tempature.

  12. Ocean acidification impairs vermetid reef recruitment.

    PubMed

    Milazzo, Marco; Rodolfo-Metalpa, Riccardo; Chan, Vera Bin San; Fine, Maoz; Alessi, Cinzia; Thiyagarajan, Vengatesen; Hall-Spencer, Jason M; Chemello, Renato

    2014-01-01

    Vermetids form reefs in sub-tropical and warm-temperate waters that protect coasts from erosion, regulate sediment transport and accumulation, serve as carbon sinks and provide habitat for other species. The gastropods that form these reefs brood encapsulated larvae; they are threatened by rapid environmental changes since their ability to disperse is very limited. We used transplant experiments along a natural CO2 gradient to assess ocean acidification effects on the reef-building gastropod Dendropoma petraeum. We found that although D. petraeum were able to reproduce and brood at elevated levels of CO2, recruitment success was adversely affected. Long-term exposure to acidified conditions predicted for the year 2100 and beyond caused shell dissolution and a significant increase in shell Mg content. Unless CO2 emissions are reduced and conservation measures taken, our results suggest these reefs are in danger of extinction within this century, with significant ecological and socioeconomic ramifications for coastal systems. PMID:24577050

  13. Comparing the invasibility of experimental "reefs" with field observations of natural reefs and artificial structures.

    PubMed

    Dafforn, Katherine A; Glasby, Tim M; Johnston, Emma L

    2012-01-01

    Natural systems are increasingly being modified by the addition of artificial habitats which may facilitate invasion. Where invaders are able to disperse from artificial habitats, their impact may spread to surrounding natural communities and therefore it is important to investigate potential factors that reduce or enhance invasibility. We surveyed the distribution of non-indigenous and native invertebrates and algae between artificial habitats and natural reefs in a marine subtidal system. We also deployed sandstone plates as experimental 'reefs' and manipulated the orientation, starting assemblage and degree of shading. Invertebrates (non-indigenous and native) appeared to be responding to similar environmental factors (e.g. orientation) and occupied most space on artificial structures and to a lesser extent reef walls. Non-indigenous invertebrates are less successful than native invertebrates on horizontal reefs despite functional similarities. Manipulative experiments revealed that even when non-indigenous invertebrates invade vertical "reefs", they are unlikely to gain a foothold and never exceed covers of native invertebrates (regardless of space availability). Community ecology suggests that invertebrates will dominate reef walls and algae horizontal reefs due to functional differences, however our surveys revealed that native algae dominate both vertical and horizontal reefs in shallow estuarine systems. Few non-indigenous algae were sampled in the study, however where invasive algal species are present in a system, they may present a threat to reef communities. Our findings suggest that non-indigenous species are less successful at occupying space on reef compared to artificial structures, and manipulations of biotic and abiotic conditions (primarily orientation and to a lesser extent biotic resistance) on experimental "reefs" explained a large portion of this variation, however they could not fully explain the magnitude of differences. PMID:22666459

  14. Remote Sensing of Coral Reef Processes

    Microsoft Academic Search

    Eric J. Hochberg

    \\u000a Digital remote sensing of coral reefs dates to the first Landsat mission of the mid-1970s. Early studies utilized moderate-spatial-resolution\\u000a satellite broadband multispectral image data and focused on reef geomorphology. Technological advances have since led to development\\u000a of airborne narrow-band hyperspectral sensors, airborne hydrographic lidar systems, and commercial high-spatial-resolution\\u000a satellite broadband multispectral imagers. High quality remote sensing data have become widely

  15. “Faster, better, cheaper” technologies used in the attitude and information management subsystem for the Mars Pathfinder mission

    Microsoft Academic Search

    D. F. Woerner; David H. Lehman

    1995-01-01

    The “Faster, Better, Cheaper” thrust at NASA\\/JPL has pushed new technologies into spacecraft designed for interplanetary missions. This is especially true for “Discovery” class missions such as Mars Pathfinder. This mission is set to send a lander and enclosed microrover to the surface of Mars for a “low cost”. The Pathfinder flight system must be built for $150M (FY92 dollars)

  16. Digital mapping of the Mars Pathfinder landing site: Design, acquisition, and derivation of cartographic products for science applications

    Microsoft Academic Search

    L. R. Gaddis; R. L. Kirk; J. R. Johnson; L. A. Soderblom; A. W. Ward; J. Barrett; K. Becker; T. Becker; J. Blue; D. Cook; E. Eliason; T. Hare; E. Howington-Kraus; C. Isbell; E. M. Lee; B. Redding; R. Sucharski; T. Sucharski; P. H. Smith; D. T. Britt

    1999-01-01

    The Imager for Mars Pathfinder (IMP) acquired more than 16,000 images and provided panoramic views of the surface of Mars at the Mars Pathfinder landing site in Ares Vallis. This paper describes the stereoscopic, multispectral IMP imaging sequences and focuses on their use for digital mapping of the landing site and for deriving cartographic products to support science applications of

  17. Digital photogrammetric analysis of the IMP camera images: Mapping the Mars Pathfinder landing site in three dimensions

    Microsoft Academic Search

    R. L. Kirk; E. Howington-Kraus; T. Hare; E. Dorrer; D. Cook; K. Becker; K. Thompson; B. Redding; J. Blue; D. Galuszka; E. M. Lee; L. R. Gaddis; J. R. Johnson; L. A. Soderblom; A. W. Ward; P. H. Smith; D. T. Britt

    1999-01-01

    This paper describes our photogrammetric analysis of the Imager for Mars Pathfinder data, part of a broader program of mapping the Mars Pathfinder landing site in support of geoscience investigations. This analysis, carried out primarily with a commercial digital photogrammetric system, supported by our in-house Integrated Software for Imagers and Spectrometers (ISIS), consists of three steps: (1) geometric control: simultaneous

  18. Coral reefs and the World Bank.

    PubMed

    Hatziolos, M

    1997-01-01

    The World Bank¿s involvement in coral reef conservation is part of a larger effort to promote the sound management of coastal and marine resources. This involves three major thrusts: partnerships, investments, networks and knowledge. As an initial partner and early supporter of the International Coral Reef Initiative (ICRI), the Bank serves as the executive planning committee of ICRI. In partnership with the World Conservation Union and the Great Barrier Reef Marine Park Authority, the Bank promotes the efforts towards the establishment and maintenance of a globally representative system of marine protected areas. In addition, the Bank invested over $120 million in coral reef rehabilitation and protection programs in several countries. Furthermore, the Bank developed a ¿Knowledge Bank¿ that would market ideas and knowledge to its clients along with investment projects. This aimed to put the best global knowledge on environmentally sustainable development in the hands of its staff and clients. During the celebration of 1997, as the International Year of the Reef, the Bank planned to cosponsor an associated event that would highlight the significance of coral reefs and encourage immediate action to halt their degradation to conserve this unique ecosystem. PMID:12295815

  19. ReefSAM - Reef Sedimentary Accretion Model: A new 3D coral reef evolution model/simulator

    NASA Astrophysics Data System (ADS)

    Barrett, Samuel; Webster, Jody

    2013-04-01

    Coral reefs show characteristic morphological patterns (e.g. coral dominated margins with detrital carbonate dominated lagoons/back-reef) and temporal development (e.g. Hopley et al. 2007). While the processes which lead to predictable patterns on a range of scales have been discussed qualitatively, a full quantitative understanding of the range of processes and parameters involved requires modelling. Previous attempts to model complex Holocene reef systems (i.e. One Tree Reef, GBR - Barrett and Webster 2012) using a carbonate stratigraphic forward model (Carbonate3D - Warrlich et al. 2002) identified a number of important but unsimulated processes and potential model improvements. ReefSAM has been written from scratch in Matlab using these findings and experiences from using Carbonate3D. It simulates coralgal accretion and carbonate sand production and transport. Specific improvements include: 1. a more complex hydrodynamic model based on wave refraction and incorporating vertical (depth) and lateral (substrate dependent) variations in transport energy and erosion. 2. a complex reef growth model incorporating depth, wave energy/turbidity and substrate composition. 3. Paleo-water depth, paleo-wave energy and bio-zone (combination of paleo-water depth and wave energy) model outputs allowing coralgal habitat changes through time and space to be simulated and compared to observational data. The model is compared to the well studied One Tree Reef - tests similar to those undertaken in Barrett and Webster 2012 with Carbonate3D are presented. Model development coincides with plans for further intensive drilling at One Tree Reef (mid 2013) providing an opportunity to test the model predictively. The model is still in active development. References: Barrett, S.J., Webster, J.M.,2012. Holocene evolution of the Great Barrier Reef: Insights from 3D numerical modelling. Sedimentary Geology 265-266, 56-71. Warrlich, G.M.D., Waltham, D.A., Bosence D.W.J., 2002. Quantifying the sequence stratigraphy and drowning mechanisms of atolls using a new 3-D forward modelling program (CARBONATE 3D). Basin Research 14, 379-400. Hopley, D., Smithers, S.G., Parnell, K.E., 2007. The geomorphology of the Great Barrier Reef. Cambridge.

  20. Pathfinder technologies for bold new missions. [U.S. research and development program for space exploration

    NASA Technical Reports Server (NTRS)

    Sadin, Stanley R.; Rosen, Robert

    1987-01-01

    Project Pathfinder is a proposed U.S. Space Research and Technology program intended to enable bold new missions of space exploration. Pathfinder continues the advancement of technological capabilities and extends the foundation established under the Civil Space Technology Initiative, CSTI. By filling critical technological gaps, CSTI enhances access to Earth orbit and supports effective operations and science missions therein. Pathfinder, with a longer-term horizon, looks to a future that builds on Shuttle and Space Station and addresses technologies that support a range of exploration missions including: a return to the Moon to build an outpost; piloted missions to Mars; and continued scientific exploration of Earth and the other planets. The program's objective is to develop, within reasonable time frames, those emerging and innovative technologies that will make possible both new and enhanced missions and system concepts.

  1. The structure of Mediterranean rocky reef ecosystems across environmental and human gradients, and conservation implications

    USGS Publications Warehouse

    Sala, Enric; Ballesteros, Enric; Dendrinos, Panagiotis; Di Franco, Antonio; Ferretti, Francesco; Foley, David; Fraschetti, Simonetta; Friedlander, Alan; Garrabou, Joaquim; Guclusoy, Harun; Guidetti, Paolo; Halpern, Benjamin S.; Hereu, Bernat; Karamanlidis, Alexandros A.; Kizilkaya, Zafer; Macpherson, Enrique; Mangialajo, Luisa; Mariani, Simone; Micheli, Fiorenza; Pais, Antonio; Riser, Kristin; Rosenberg, Andrew A.; Sales, Marta; Selkoe, Kimberly A.; Starr, Rick; Tomas, Fiona; Zabala, Mikel

    2012-01-01

    Historical exploitation of the Mediterranean Sea and the absence of rigorous baselines makes it difficult to evaluate the current health of the marine ecosystems and the efficacy of conservation actions at the ecosystem level. Here we establish the first current baseline and gradient of ecosystem structure of nearshore rocky reefs at the Mediterranean scale. We conducted underwater surveys in 14 marine protected areas and 18 open access sites across the Mediterranean, and across a 31-fold range of fish biomass (from 3.8 to 118 g m-2). Our data showed remarkable variation in the structure of rocky reef ecosystems. Multivariate analysis showed three alternative community states: (1) large fish biomass and reefs dominated by non-canopy algae, (2) lower fish biomass but abundant native algal canopies and suspension feeders, and (3) low fish biomass and extensive barrens, with areas covered by turf algae. Our results suggest that the healthiest shallow rocky reef ecosystems in the Mediterranean have both large fish and algal biomass. Protection level and primary production were the only variables significantly correlated to community biomass structure. Fish biomass was significantly larger in well-enforced no-take marine reserves, but there were no significant differences between multi-use marine protected areas (which allow some fishing) and open access areas at the regional scale. The gradients reported here represent a trajectory of degradation that can be used to assess the health of any similar habitat in the Mediterranean, and to evaluate the efficacy of marine protected areas.

  2. Internal structure and Holocene evolution of One Tree Reef, southern Great Barrier Reef

    Microsoft Academic Search

    J. F. Marshall; P. J. Davies

    1982-01-01

    Analysis of core from six drill holes and ten vibrocores from One Tree Reef has delineated five major biosedimentological facies: algal pavement, coral head facies, branching coral facies, reef flat rubble facies and sand facies. Holocene growth began around 8,000 years B.P. with a high energy coral head facies on windward margins and a lower energy branching coral facies on

  3. Video-monitored predation by Caribbean reef fishes on an array of mangrove and reef sponges

    Microsoft Academic Search

    M. Dunlap; J. R. Pawlik

    1996-01-01

    Although predation by fishes is thought to structure benthic invertebrate communities on coral reefs, evidence to support this claim has been difficult to obtain. We deployed an array of eight sponge species on Conch Reef (16 m depth) off Key Largo, Florida, USA, and used a remote video-camera to record fish activity near the array continuously during five daylight periods

  4. Estimation of photosynthesis and calcification rates at a fringing reef by accounting for diurnal variations and the zonation of coral reef communities on reef flat and slope: a case study for the Shiraho reef, Ishigaki Island, southwest Japan

    NASA Astrophysics Data System (ADS)

    Nakamura, T.; Nakamori, T.

    2009-03-01

    Seven coral reef communities were defined on Shiraho fringing reef, Ishigaki Island, Japan. Net photosynthesis and calcification rates were measured by in situ incubations at 10 sites that included six of the defined communities, and which occupied most of the area on the reef flat and slope. Net photosynthesis on the reef flat was positive overall, but the reef flat acts as a source for atmospheric CO2, because the measured calcification/photosynthesis ratio of 2.5 is greater than the critical ratio of 1.67. Net photosynthesis on the reef slope was negative. Almost all excess organic production from the reef flat is expected to be effused to the outer reef and consumed by the communities there. Therefore, the total net organic production of the whole reef system is probably almost zero and the whole reef system also acts as a source for atmospheric CO2. Net calcification rates of the reef slope corals were much lower than those of the branching corals. The accumulation rate of the former was approximately 0.5 m kyr-1 and of the latter was ~0.7-5 m kyr-1. Consequently, reef slope corals could not grow fast enough to keep up with or catch up to rising sea levels during the Holocene. On the other hand, the branching corals grow fast enough to keep up with this rising sea level. Therefore, a transition between early Holocene and present-day reef communities is expected. Branching coral communities would have dominated while reef growth kept pace with sea level rise, and the reef was constructed with a branching coral framework. Then, the outside of this framework was covered and built up by reef slope corals and present-day reefs were constructed.

  5. Remote video bioassays reveal the potential feeding impact of the rabbitfish Siganus canaliculatus (f: Siganidae) on an inner-shelf reef of the Great Barrier Reef

    Microsoft Academic Search

    R. J. Fox; D. R. Bellwood

    2008-01-01

    Herbivores are widely acknowledged as key elements maintaining the health and resilience of terrestrial and aquatic ecosystems.\\u000a Understanding and quantifying the impact of herbivores in ecosystems are fundamental to our ability to manage these systems.\\u000a The traditional method of quantifying the impact of herbivorous fishes on coral reefs has been to use transplanted pieces\\u000a of seagrass or algae as “bioassays”.

  6. The Lisa Technology Package (LTP) Diagnostics In Lisa Pathfinder

    NASA Astrophysics Data System (ADS)

    Sanjuan, Josep; Lobo, A.; Cañizares, P.; Conchillo, A.; Conchillo, A.; Gesa, L.; Grimani, C.; Lloro, I.; Mateos, I.; Nofrarias, M.; Ramos-Castro, J.; Sopuerta, C.

    2010-01-01

    LISA PathFinder (LPF) will be flown with the objective to test in space key technologies

  7. General geology and geomorphology of the Mars Pathfinder landing site

    USGS Publications Warehouse

    Ward, A.W.; Gaddis, L.R.; Kirk, R.L.; Soderblom, L.A.; Tanaka, K.L.; Golombek, M.P.; Parker, T.J.; Greeley, Ronald; Kuzmin, R.O.

    1999-01-01

    The Mars Pathfinder (MPF) spacecraft landed on relatively young (late Hesperian-early Amazonian; 3.1-0.7 Ga) plains in Chryse Planitia near the mouth of Ares Vallis. Images returned from the spacecraft reveal a complex landscape of ridges and troughs, large hills and crater rims, rocks and boulders of various sizes and shapes, and surficial deposits, indicating a complex, multistage geologic history of the landing site. After the deposition of one or more bedrock units, depositional and erosional fluvial processes shaped much of the present landscape. Multiple erosional events are inferred on the basis of observations of numerous channels, different orientations of many streamlined tails from their associated knobs and hills, and superposition of lineations and streamlines. Medium- and small-scale features, interpreted to be related to late-stage drainage of floodwaters, are recognized in several areas at the landing site. Streamlined knobs and hills seen in Viking orbiter images support this inference, as they seem to be complex forms, partly erosional and partly depositional, and may also indicate a series of scouring and depositional events that, in some cases, further eroded or partially buried these landforms. Although features such as these are cited as evidence for catastrophic flooding at Ares Vallis, some of these features may also be ascribed to alternative primary or secondary depositional processes, such as glacial or mass-wasting processes. Close inspection of the landing site reveals rocks that are interpreted to be volcanic in origin and others that may be conglomeratic. If such sedimentary rocks are confirmed, fluvial processes have had a greater significance on Mars than previously thought. For the last several hundred million to few billion years, eolian processes have been dominant. Dunes and dune-like features, ventifacts, and deflation and exhumation features around several rocks probably are the most recent landforms. The relatively pristine nature of the overall landscape at the MPF site suggests weathering and erosion processes on Mars are exceptionally slow.

  8. Motoneuron axon pathfinding errors in zebrafish: differential effects related to concentration and timing of nicotine exposure.

    PubMed

    Menelaou, Evdokia; Paul, Latoya T; Perera, Surangi N; Svoboda, Kurt R

    2015-04-01

    Nicotine exposure during embryonic stages of development can affect many neurodevelopmental processes. In the developing zebrafish, exposure to nicotine was reported to cause axonal pathfinding errors in the later born secondary motoneurons (SMNs). These alterations in SMN axon morphology coincided with muscle degeneration at high nicotine concentrations (15-30 ?M). Previous work showed that the paralytic mutant zebrafish known as sofa potato exhibited nicotine-induced effects onto SMN axons at these high concentrations but in the absence of any muscle deficits, indicating that pathfinding errors could occur independent of muscle effects. In this study, we used varying concentrations of nicotine at different developmental windows of exposure to specifically isolate its effects onto subpopulations of motoneuron axons. We found that nicotine exposure can affect SMN axon morphology in a dose-dependent manner. At low concentrations of nicotine, SMN axons exhibited pathfinding errors, in the absence of any nicotine-induced muscle abnormalities. Moreover, the nicotine exposure paradigms used affected the 3 subpopulations of SMN axons differently, but the dorsal projecting SMN axons were primarily affected. We then identified morphologically distinct pathfinding errors that best described the nicotine-induced effects on dorsal projecting SMN axons. To test whether SMN pathfinding was potentially influenced by alterations in the early born primary motoneuron (PMN), we performed dual labeling studies, where both PMN and SMN axons were simultaneously labeled with antibodies. We show that only a subset of the SMN axon pathfinding errors coincided with abnormal PMN axonal targeting in nicotine-exposed zebrafish. We conclude that nicotine exposure can exert differential effects depending on the levels of nicotine and developmental exposure window. PMID:25668718

  9. Biologic response to environmental stress in tropical reefs: Lessons from modern Polynesian coralgal atolls and Middle Permian sponge and Shamovella microbe reefs (Capitan Limestone USA)

    Microsoft Academic Search

    J. A. Fagerstrom; O. Weidlich

    2005-01-01

    Despite prejudices that comparisons of paleoecological patterns in modern and fossil reef communities are of doubtful validity, we compare the biologic response of living coralgal reefs in French Polynesia to environmental stress with an exceptionally well exposed Middle Permian sponge reef and Shamovella-microbial reef of the Capitan Limestone in New Mexico. In the western Tuamotu Archipelago, reef margins are characterized

  10. Observations by the Mars 1994 orbiter and possible correlations with Mars Pathfinder

    NASA Technical Reports Server (NTRS)

    Keller, H. Uwe

    1994-01-01

    The Mars '94 spacecraft will still be operational when Mars Pathfinder begins its observations. While it will probably not be possible to detect the lander directly, the terrain, including the landing error ellipse, can be covered in high resolution (10 m) in various color bands. The stereo capability of the high resolution camera will provide a three-dimensional terrain map. The landing site of Pathfinder could possibly be chosen so that correlated observations of IMP and the remote sensing instruments onboard Mars '94 may be possible. We will discuss this scenario based on the presently adopted Mars '94 orbit and resulting enhancements stemming from correlations of data obtained by both spacecraft.

  11. Phase 2 pilot study of Pathfinders: a psychosocial intervention for cancer patients

    Microsoft Academic Search

    Amy P. Abernethy; James E. Herndon; April Coan; Tina Staley; Jane L. Wheeler; Krista Rowe; Sophia K. Smith; H. Kim Lyerly

    2010-01-01

    Purpose  Pathfinders is a multi-faceted psychosocial care program for cancer patients; it was developed in community oncology and adapted\\u000a to the academic oncology setting. This prospective, single-arm, phase 2 pilot study examined the acceptability and feasibility\\u000a of Pathfinders for women with metastatic breast cancer.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Over 3 months, participants completed patient-reported surveys including the Patient Care Monitor (PCM, review of systems),\\u000a Functional Assessment

  12. Mineralogic and compositional properties of Martian soil and dust: results from Mars Pathfinder

    USGS Publications Warehouse

    Bell, J.F., III; McSween, H.Y., Jr.; Crisp, J.A.; Morris, R.V.; Murchie, S.L.; Bridges, N.T.; Johnson, J.R.; Britt, D.T.; Golombek, M.P.; Moore, H.J.; Ghosh, A.; Bishop, J.L.; Anderson, R.C.; Brückner, J.; Economou, T.; Greenwood, J.P.; Gunnlaugsson, H.P.; Hargraves, R.M.; Hviid, S.; Knudsen, J.M.; Madsen, M.B.; Reid, R.; Rieder, R.; Soderblom, L.

    2000-01-01

    Mars Pathfinder obtained multispectral, elemental, magnetic, and physical measurements of soil and dust at the Sagan Memorial Station during the course of its 83 sol mission. We describe initial results from these measurements, concentrating on multispectral and elemental data, and use these data, along with previous Viking, SNC meteorite, and telescopic results, to help constrain the origin and evolution of Martian soil and dust. We find that soils and dust can be divided into at least eight distinct spectral units, based on parameterization of Imager for Mars Pathfinder (IMP) 400 to 1000 nm multispectral images. The most distinctive spectral parameters for soils and dust are the reflectivity in the red, the red/blue reflectivity ratio, the near-IR spectral slope, and the strength of the 800 to 1000 nm absorption feature. Most of the Pathfinder spectra are consistent with the presence of poorly crystalline or nanophase ferric oxide(s), sometimes mixed with small but varying degrees of well-crystalline ferric and ferrous phases. Darker soil units appear to be coarser-grained, compacted, and/or mixed with a larger amount of dark ferrous materials relative to bright soils. Nanophase goethite, akaganeite, schwertmannite, and maghemite are leading candidates for the origin of the absorption centered near 900 nm in IMP spectra. The ferrous component in the soil cannot be well-constrained based on IMP data. Alpha proton X-ray spectrometer (APXS) measurements of six soil units show little variability within the landing site and show remarkable overall similarity to the average Viking-derived soil elemental composition. Differences exist between Viking and Pathfinder soils, however, including significantly higher S and Cl abundances and lower Si abundances in Viking soils and the lack of a correlation between Ti and Fe in Pathfinder soils. No significant linear correlations were observed between IMP spectral properties and APXS elemental chemistry. Attempts at constraining the mineralogy of soils and dust using normative calculations involving mixtures of smectites and silicate and oxide minerals did not yield physically acceptable solutions. We attempted to use the Pathfinder results to constrain a number of putative soil and dust formation scenarios, including palagonitization and acid-fog weathering. While the Pathfinder soils cannot be chemically linked to the Pathfinder rocks by palagonitization, this study and McSween et al. [1999] suggest that palagonitic alteration of a Martian basaltic rock, plus mixture with a minor component of locally derived andesitic rock fragments, could be consistent with the observed soil APXS and IMP properties.

  13. Reef Odor: A Wake Up Call for Navigation in Reef Fish Larvae

    PubMed Central

    Paris, Claire B.; Kingsford, Michael; Gerlach, Gabriele; Guigand, Cedric M.

    2013-01-01

    The behavior of reef fish larvae, equipped with a complex toolbox of sensory apparatus, has become a central issue in understanding their transport in the ocean. In this study pelagic reef fish larvae were monitored using an unmanned open-ocean tracking device, the drifting in-situ chamber (DISC), deployed sequentially in oceanic waters and in reef-born odor plumes propagating offshore with the ebb flow. A total of 83 larvae of two taxonomic groups of the families Pomacentridae and Apogonidae were observed in the two water masses around One Tree Island, southern Great Barrier Reef. The study provides the first in-situ evidence that pelagic reef fish larvae discriminate reef odor and respond by changing their swimming speed and direction. It concludes that reef fish larvae smell the presence of coral reefs from several kilometers offshore and this odor is a primary component of their navigational system and activates other directional sensory cues. The two families expressed differences in their response that could be adapted to maintain a position close to the reef. In particular, damselfish larvae embedded in the odor plume detected the location of the reef crest and swam westward and parallel to shore on both sides of the island. This study underlines the critical importance of in situ Lagrangian observations to provide unique information on larval fish behavioral decisions. From an ecological perspective the central role of olfactory signals in marine population connectivity raises concerns about the effects of pollution and acidification of oceans, which can alter chemical cues and olfactory responses. PMID:24015278

  14. Sun Compass Orientation Helps Coral Reef Fish Larvae Return to Their Natal Reef

    PubMed Central

    Mouritsen, Henrik; Atema, Jelle; Kingsford, Michael J.; Gerlach, Gabriele

    2013-01-01

    Reef fish sustain populations on isolated reefs and show genetic diversity between nearby reefs even though larvae of many species are swept away from the natal site during pelagic dispersal. Retention or recruitment to natal reefs requires orientation capabilities that enable larvae to find their way. Although olfactory and acoustically based orientation has been implicated in homing when larvae are in the reef’s vicinity, it is still unclear how they cope with greater distances. Here we show evidence for a sun compass mechanism that can bring the larvae to the vicinity of their natal reef. In a circular arena, pre-settlement larvae and early settlers (<24 hours) of the cardinal fish, Ostorhinchus doederleini, showed a strong SSE directional swimming response, which most likely has evolved to compensate for the locally prevailing large scale NNW current drift. When fish were clock-shifted 6 hours, they changed their orientation by ca. 180° as predicted by the tropical sun curve at One Tree Island, i.e. they used a time-compensated sun compass. Furthermore, the fish oriented most consistently at times of the day when the sun azimuth is easy to determine. Microsatellite markers showed that the larvae that had just arrived at One Tree Island genetically belonged to either the local reef population or to Fitzroy Reef located 12 kilometers to the SSE. The use of a sun compass adds a missing long-distance link to the hierarchy of other sensory abilities that can direct larvae to the region of origin, including their natal reef. Predominant local recruitment, in turn, can contribute to genetic isolation and potential speciation. PMID:23840396

  15. Habitat degradation is threatening reef replenishment by making fish fearless.

    PubMed

    Lönnstedt, Oona M; McCormick, Mark I; Chivers, Douglas P; Ferrari, Maud C O

    2014-09-01

    Habitat degradation is one of the 'Big Five' drivers of biodiversity loss. However, the mechanisms responsible for this progressive loss of biodiversity are poorly understood. In marine ecosystems, corals play the role of ecosystem engineers, providing essential habitat for hundreds of thousands of species and hence their health is crucial to the stability of the whole ecosystem. Climate change is causing coral bleaching and degradation, and while this has been known for a while, little do we know about the cascading consequences of these events on the complex interrelationships between predators and their prey. The goal of our study was to investigate, under completely natural conditions, the effect of coral degradation on predator-prey interactions. Settlement stage ambon damselfish (Pomacentrus amboinensis), a common tropical fish, were released on patches of healthy or dead corals, and their behaviours in situ were measured, along with their response to injured conspecific cues, a common risk indicator. This study also explored the effect of habitat degradation on natural levels of mortality at a critical life-history transition. We found that juveniles in dead corals displayed risk-prone behaviours, sitting further away and higher up on the reef patch, and failed to respond to predation cues, compared to those on live coral patches. In addition, in situ survival experiments over 48 h indicated that juveniles on dead coral habitats had a 75% increase in predation-related mortality, compared to fish released on live, healthy coral habitats. Our results provide the first of many potential mechanisms through which habitat degradation can impact the relationship between prey and predators in the coral reef ecosystem. As the proportion of dead coral increases, the recruitment and replenishment of coral reef fishes will be threatened, and so will the level of diversity in these biodiversity hot spots. PMID:24498854

  16. Coralline reefs classification in Banco Chinchorro, Mexico

    NASA Astrophysics Data System (ADS)

    Contreras-Silva, Ameris I.; López-Caloca, Alejandra A.

    2009-09-01

    The coralline reefs in Banco Chinchorro, Mexico, are part of the great reef belt of the western Atlantic. This reef complex is formed by an extensive coralline structure with great biological richness and diversity of species. These colonies are considered highly valuable ecologically, economically, socially and culturally, and they also inherently provide biological services. Fishing and scuba diving have been the main economic activities in this area for decades. However, in recent years, there has been a bleaching process and a decrease of the coral colonies in Quintana Roo, Mexico. This drop is caused mainly by the production activities performed in the oil platforms and the presence of hurricanes among other climatic events. The deterioration of the reef system can be analyzed synoptically using remote sensing. Thanks to this type of analysis, it is possible to have updated information of the reef conditions. In this paper, satellite imagery in Landsat TM and SPOT 5 is applied in the coralline reefs classification in the 1980- 2006 time period. Thus, an integral analysis of the optical components of the water surrounding the coralline reefs, such as on phytoplankton, sediments, yellow substance and even on the same water adjacent to the coral colonies, is performed. The use of a texture algorithm (Markov Random Field) was a key tool for their identification. This algorithm, does not limit itself to image segmentation, but also works on edge detection. In future work the multitemporal analysis of the results will determine the deterioration degree of these habitats and the conservation status of the coralline areas.

  17. The National Oceanic and Atmospheric Administration's Coral Reef Conservation Program

    NSDL National Science Digital Library

    This NOAA program supports effective management and sound science to preserve, sustain and restore valuable coral reef ecosystems. Students can read about the U.S. Coral Reef Task Force, learn more about local and national coral reef action strategies, and find links to more information on coral reefs. The site also offers a search for publications and data and a general search of the site.

  18. Where in the world are Winslow Reef and Amelia Earhart?

    Microsoft Academic Search

    R. S. Jacobson

    1994-01-01

    Uncharted or doubtful positions of shoals and reefs have played a large role in the history of maritime navigation and oceanography. Two of these shoals, Winslow Reef and Reef and Sand Bank in the central equatorial Pacific, were the subjects of a fruitless 2-day aerial search in 1937 for Amelia Earhart by planes from the battleship USS Colorado.Sightings before and

  19. Coral Reefs: A Gallery Program, Grades 7-12.

    ERIC Educational Resources Information Center

    National Aquarium in Baltimore, MD. Dept. of Education.

    Gallery classes at the National Aquarium in Baltimore give the opportunity to study specific aquarium exhibits which demonstrate entire natural habitats. The coral reef gallery class features the gigantic western Atlantic coral reef (325,000 gallons) with over 1,000 fish. The exhibit simulates a typical Caribbean coral reef and nearby sandy…

  20. Coral Reef Education and Australian High School Students

    ERIC Educational Resources Information Center

    Stepath, Carl M.

    2004-01-01

    Educational programs that focus on humans and their relationship to coral reefs are becoming necessary, as reef structures along the Queensland coast come under mounting ecological pressure. This paper reports on a PhD research project which investigated marine education and learning with high school students in coral reef environments along the…

  1. EFFECTS OF DRILLING FLUIDS ON REEF CORALS: A REVIEW

    EPA Science Inventory

    This chapter reviews research on the effects of drilling mud on coral reef communities, concentrating on the major reef fauna: the reef-building or hermatypic corals. Drilling mud is an effluent introduced to the marine environment in large quantities during the typical offshore ...

  2. Chemical degradation characteristics of reinforced concrete reefs in South Korea

    Microsoft Academic Search

    H. S. Kim; C. G. Kim; W. B. Na; J. K. Kim

    2008-01-01

    The chemical degradation characteristics of reinforced concrete reefs, which had been fully immersed in Tongyeong waters of South Korea for 18–25 years, were studied. In order to investigate the marine environmental impact on the concrete reefs, environmental factors, for example pH, have been observed between 1997 and 2002. Then, four reinforced concrete reefs recovered from different sites in Tongyeong waters

  3. Patterns in the use of space by benthic communities on two coral reefs of the Great Barrier Reef

    Microsoft Academic Search

    R. E. Reichelt; Y. Loya; R. H. Bradbury

    1986-01-01

    A rapid benthic line-transect survey method for use by non-specialist observers is described. At both Davies Reef (mid-continental shelf) and Myrmidon Reef (outer-continental shelf) in the central Great Barrier Reef a set of 6 sites of varying depths on the reef flat, crest and slope were sampled using this method. At least 10 contiguous 10 m transects were made at

  4. Quantitative analysis of LISA pathfinder test-mass noise

    NASA Astrophysics Data System (ADS)

    Ferraioli, Luigi; Congedo, Giuseppe; Hueller, Mauro; Vitale, Stefano; Hewitson, Martin; Nofrarias, Miquel; Armano, Michele

    2011-12-01

    LISA Pathfinder (LPF) is a mission aiming to test the critical technology for the forthcoming space-based gravitational-wave detectors. The main scientific objective of the LPF mission is to demonstrate test masses free falling with residual accelerations below 3×10-14ms-2/Hz at 1 mHz. Reaching such an ambitious target will require a significant amount of system optimization and characterization, which will in turn require accurate and quantitative noise analysis procedures. In this paper, we discuss two main problems associated with the analysis of the data from LPF: i) excess noise detection and ii) noise parameter identification. The mission is focused on the low-frequency region ([0.1, 10] mHz) of the available signal spectrum. In such a region, the signal is dominated by the force noise acting on test masses. At the same time, the mission duration is limited to 90 days and typical data segments will be 24 hours in length. Considering those constraints, noise analysis is expected to deal with a limited amount of non-Gaussian data, since the spectrum statistics will be far from Gaussian and the lowest available frequency is limited by the data length. In this paper, we analyze the details of the expected statistics for spectral data and develop two suitable excess noise estimators. One is based on the statistical properties of the integrated spectrum, the other is based on the Kolmogorov-Smirnov test. The sensitivity of the estimators is discussed theoretically for independent data, then the algorithms are tested on LPF synthetic data. The test on realistic LPF data allows the effect of spectral data correlations on the efficiency of the different noise excess estimators to be highlighted. It also reveals the versatility of the Kolmogorov-Smirnov approach, which can be adapted to provide reasonable results on correlated data from a modified version of the standard equations for the inversion of the test statistic. Closely related to excess noise detection, the problem of noise parameter identification in non-Gaussian data is approached in two ways. One procedure is based on the maximum-likelihood estimator and another is based on the Kolmogorov-Smirnov goodness-of-fit estimator. Both approaches provide unbiased and accurate results for noise parameter estimation and demonstrate superior performance with respect to standard weighted least squares and Huber’s norm. We also discuss the advantages of the Kolmogorov-Smirnov formalism for the estimation of confidence intervals of parameter values in correlated data.

  5. Detecting ecological change on coral reefs

    NASA Astrophysics Data System (ADS)

    Dustan, P.

    2011-12-01

    Remote sensing offers the potential to observe the response of coral reef ecosystems to environmental perturbations on a geographical scale not previously accessible. However, coral reef environments are optically, spatially, and temporally complex habitats which all present significant challenges for extracting meaningful information. Virtually every member of the reef community possesses some degree of photosynthetic capability. The community thus generates a matrix of fine scale features with bio-optical signatures that blend as the scale of observation increases. Furthermore, to have any validity, the remotely sensed signal must be "calibrated" to the bio-optics of the reef, a difficult and resource intensive process due to a convergence of photosynthetic light harvesting by green, red, and brown algal pigment systems. To make matters more complex, reefs are overlain by a seawater skin with its own set of hydrological optical challenges. Rather than concentrating on classification, my research has attempted to track change by following the variation in geo-referenced pixel brightness over time with a technique termed temporal texture. Environmental periodicities impart a phenology to the variation in brightness and departures from the norm are easily detected as statistical outliers. This opens the door to using current orbiting technology to efficiently examine large areas of sea for change. If hot spots are detected, higher resolution sensors and field studies can be focused as resources permit. While this technique does not identify the type of change, it is sensitive, simple to compute, easy to automate and grounded in ecological niche theory

  6. Distributions of coral reef macroalgae in a back reef habitat in Moorea, French Polynesia

    NASA Astrophysics Data System (ADS)

    Poray, A. K.; Carpenter, R. C.

    2014-03-01

    On tropical reefs where macroalgae are subjected to continuous herbivore pressure, spatial refuges typically are identified as large-scale, landscape interfaces that limit foraging behavior. However, algal distributions and community assemblages may also rely on the availability of smaller scale spatial refuges within the reef. The results of this study demonstrate that the patterns of macroalgal distribution across the back reef of Moorea, French Polynesia, are maintained by herbivores interacting with the small-scale structural complexities of the coral reef landscape. Although the majority of space available for colonization is composed of exposed surfaces, macroalgae rarely are found in the open. Instead, macroalgal occurrence is highest in the protected narrow crevices and hole microhabitats provided by massive Porites spp. coral heads. These distributions are determined initially by post-settlement mortality of young algal recruits in exposed habitats. Rates of consumption for two of the most common macroalgal species found in refuges across the back reef, Halimeda minima and Amansia rhodantha, indicate that algal recruits in exposed habitats are limited by herbivory. While algal abundance and community structure are highly dependent upon herbivore grazing, the availability of small-scale spatial refuges ultimately shapes the distinct community patterns and distributional boundaries of coral reef macroalgae in the back reefs of Moorea.

  7. 76 FR 68711 - Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-07

    ...Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and Invertebrates...Islands, and Amendment 3 to the FMP for Corals and Reef Associated Plants and Invertebrates...procedures for the spiny lobster and Caribbean corals and reef associated plants and...

  8. 76 FR 82413 - Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-30

    ...Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and Invertebrates...Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and Invertebrates...FMP), and Amendment 3 to the FMP for Corals and Reef Associated Plants and...

  9. The Tangible Pathfinder Design of a Wayfinding Trainer for the Visually Impaired

    E-print Network

    Sharlin, Ehud

    cognitive map. ·On-site mobility assistance when physically walking through the environment. Detachable. The Tangible Pathfinder design goals: ·Autonomous learning of a new place, ·Self-assessment of the resulting designed from the point-of-view of a vision-impaired person walking with a cane. Objects represent common

  10. Thinking Too Much: Pathology in Pathfinding Mitja Lustrek 1 and Vadim Bulitko 2

    E-print Network

    Lu?trek, Mitja

    Thinking Too Much: Pathology in Pathfinding Mitja Lustrek 1 and Vadim Bulitko 2 1 INTRODUCTION termed minimax pathology. More re- cently pathological behavior was discovered in single-agent search as well [3]. Some attempts to explain it have been made [5, 6], but the pathology in single-agent search

  11. The Mars Pathfinder landing site and the Viking control point network

    Microsoft Academic Search

    Wolfgang Zeitler; Jürgen Oberst

    1999-01-01

    We recomputed the Viking Mars control point network and derived Mars-fixed three-dimensional coordinates of 3739 selected, globally distributed landmarks. Mars Pathfinder and Viking Lander 1 coordinates as well as data from reanalyzed spacecraft occultation measurements are used as fixed control information in the analysis. The network benefits greatly from recently restored Viking orbiter trajectory data and new planet rotational parameters

  12. Geology of Xanthe Terra outflow channels and the Mars Pathfinder landing site

    Microsoft Academic Search

    David M. Nelson; Ronald Greeley

    1999-01-01

    The Mars Pathfinder landing site (MPLS) was selected for its location at the mouths of Ares and Tiu Valles outflow channels on Mars, where sediments from a variety of geologic units could have accumulated in a lacustrine environment. Recent geologic mapping at 1:2M scale of the Xanthe Terra channels and Chryse Planitia near MPLS reveals a progression of fluvial erosion

  13. Uncoupling nicotine mediated motoneuron axonal pathfinding errors and muscle degeneration in zebrafish

    SciTech Connect

    Welsh, Lillian [Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, 70803 (United States); Tanguay, Robert L. [Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis Oregon, 97331 (United States); Svoboda, Kurt R. [Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, 70803 (United States)], E-mail: ksvobo1@lsu.edu

    2009-05-15

    Zebrafish embryos offer a unique opportunity to investigate the mechanisms by which nicotine exposure impacts early vertebrate development. Embryos exposed to nicotine become functionally paralyzed by 42 hpf suggesting that the neuromuscular system is compromised in exposed embryos. We previously demonstrated that secondary spinal motoneurons in nicotine-exposed embryos were delayed in development and that their axons made pathfinding errors (Svoboda, K.R., Vijayaraghaven, S., Tanguay, R.L., 2002. Nicotinic receptors mediate changes in spinal motoneuron development and axonal pathfinding in embryonic zebrafish exposed to nicotine. J. Neurosci. 22, 10731-10741). In that study, we did not consider the potential role that altered skeletal muscle development caused by nicotine exposure could play in contributing to the errors in spinal motoneuron axon pathfinding. In this study, we show that an alteration in skeletal muscle development occurs in tandem with alterations in spinal motoneuron development upon exposure to nicotine. The alteration in the muscle involves the binding of nicotine to the muscle-specific AChRs. The nicotine-induced alteration in muscle development does not occur in the zebrafish mutant (sofa potato, [sop]), which lacks muscle-specific AChRs. Even though muscle development is unaffected by nicotine exposure in sop mutants, motoneuron axonal pathfinding errors still occur in these mutants, indicating a direct effect of nicotine exposure on nervous system development.

  14. Improvements to the NOAA\\/NASA 8-km Pathfinder AVHRR Land Data Set

    Microsoft Academic Search

    J. M. McManus; R. H. Rank; T. Zhu; P. M. Smith; J. D. Grogard

    2001-01-01

    This poster presents continual improvements being made to the NOAA\\/NASA 8-km Pathfinder AVHRR Land (PAL) data sets. PAL is a global land surface data set, derived from the Advanced Very High Resolution Radiometer (AVHRR), on the NOAA polar orbiting satellite series, which provides a continuous daily and 10-day composite data set from July 1981 through the present. Parameters include the

  15. The evolving starburst-AGN connection: Implications for SKA and its pathfinders

    E-print Network

    Norris, Ray

    The evolving starburst-AGN connection: Implications for SKA and its pathfinders Ray P. Norris CSIRO ATNF E-mail: Ray.Norris@csiro.au Enno Middelberg University of Bochum E-mail: middelberg@astro.rub.de Brian J. Boyle CSIRO ATNF E-mail: Brian.Boyle@csiro.au How well is the modern-day starburst

  16. Real-time Heuristic Search for Pathfinding in Video Games Vadim Bulitko

    E-print Network

    Björnsson, Yngvi

    Real-time Heuristic Search for Pathfinding in Video Games Vadim Bulitko bulitko@ualberta.ca Yngvi a complete, possibly abstract, path for each agent before the agent can move. Real-time heuristic search, until recently, real-time heuristic search algorithms universally exhibited a visually unappeal- ing

  17. Lookahead Pathology in Real-Time Path-Finding Mitja Lustrek

    E-print Network

    LuÂ?trek, Mitja

    Large real-time search problems such as path-finding in com- puter games and robotics limit the applicability of complete search methods such as A*. As a result, real-time heuris- tic methods are becoming-agent search. As real-time search methods gain ground in applications, the importance of un- derstanding

  18. Taking Learning out of Real-time Heuristic Search for Video-game Pathfinding

    E-print Network

    Lawrence, Ramon

    Taking Learning out of Real-time Heuristic Search for Video-game Pathfinding Ramon Lawrence1, bulitko@ualberta.ca Abstract. Real-time heuristic search algorithms are useful when the amount of time's commands. Classic real-time heuristic search algorithms cannot be deployed due to their obvious state

  19. Thinking Too Much: Pathology in Pathfinding Mitja Lustrek 1 and Vadim Bulitko 2

    E-print Network

    LuÂ?trek, Mitja

    real-time search problems, such as pathfinding in computer games and robotics, limit the applicability of complete search methods, such as A*. Real-time heuristic search methods are better suited to these problems examples in single-agent search. This paper conducts a large-scale investigation of the pathology in real-time

  20. REVIEW OF THE TRAJECTORY AND ATMOSPHERIC STRUCTURE RECONSTRUCTION FOR MARS PATHFINDER

    E-print Network

    Withers, Paul

    .c.zarnecki@open.ac.uk) Introduction: Mars Pathfinder (MPF) used a novel landing technique to reach the surface of Mars on July 4th, then dropped to the surface inside a cocoon of airbags. Accelerometers: MPF's entry state, given in [7's centre of mass was on its symmetry axis, which kept its angle of attack below 5 degrees. "Each

  1. The versatile GPS Pathfinder Pro XRS receiver is the thoroughbred of GPS

    E-print Network

    Gilbes, Fernando

    The versatile GPS Pathfinder® Pro XRS receiver is the thoroughbred of GPS receivers. Offering a full range of accurate real-time correction sources, great performance in all GPS conditions and maintaining GPS data. Built to meet your demands With the Pro XRS receiver, you don't have to worry whether

  2. Mars Pathfinder meteorological observations on the basis of results of an atmospheric global circulation model

    Microsoft Academic Search

    Francois Forget; F. Hourdin; O. Talagrand

    1994-01-01

    The Mars Pathfinder Meteorological Package (ASI\\/MET) will measure the local pressure, temperature, and winds at its future landing site, somewhere between the latitudes 0 deg N and 30 deg N. Comparable measurements have already been obtained at the surface of Mars by the Viking Landers at 22 deg N (VL1) and 48 deg N (VL2), providing much useful information on

  3. NOAA Technical Memorandum ERL GLERL-53 "PATHFINDER"--A TBAJECTORY PREDICTION

    E-print Network

    , and particle paths in several different formats. 1. INTRODUCTION The "PATHFINDER" trajectory prediction system particles in the Great Lakes. These particle trajectories can be used to estimate the motion of spilled oil SPILL INFORMATION 7. THE TRAJECTORY MODEL 8. TRAJECTORY DISPLAYS 9. COMPUTATIONAL GRIDS 10. REFERENCES

  4. Using Virtual Reality For Science Mission Planning: A Mars Pathfinder Case

    Microsoft Academic Search

    Jacqueline H. Kim; Richard J. Weidner; Allan L. Sacks

    1994-01-01

    Mars Pathfinder Project requires a Ground Data System that supports both anengineering and a science payload with reduced mission operations and planningschedules. Also, successful surface operation of the lander camera requires efficient mission planningand accurate pointing of the camera,To meet these challenges, the GDS Team designed a new software strategy that integrates virtualreality technology with existing JPL Navigational Ancillary Information

  5. Overview of the Mars Pathfinder Mission and Assessment of Landing Site Predictions

    Microsoft Academic Search

    M. P. Golombek; R. A. Cook; T. Economou; W. M. Folkner; A. F. C. Haldemann; P. H. Kallemeyn; J. M. Knudsen; R. M. Manning; H. J. Moore; T. J. Parker; R. Rieder; J. T. Schofield; P. H. Smith; R. M. Vaughan

    1997-01-01

    Chemical analyses returned by Mars Pathfinder indicate that some rocks may be high in silica, implying differentiated parent materials. Rounded pebbles and cobbles and a possible conglomerate suggest fluvial processes that imply liquid water in equilibrium with the atmosphere and thus a warmer and wetter past. The moment of inertia indicates a central metallic core of 1300 to 2000 kilometers

  6. Overview of the Mars Pathfinder Mission: Launch through landing, surface operations, data sets, and science results

    Microsoft Academic Search

    M. P. Golombek; N. T. Bridges; H. J. Moore; S. L. Murchie; J. R. Murphy; T. J. Parker; R. Rieder; T. P. Rivellini; J. T. Schofield; A. Seiff; R. B. Singer; P. H. Smith; L. A. Soderblom; D. A. Spencer; C. R. Stoker; R. Sullivan; N. Thomas; S. W. Thurman; M. G. Tomasko; R. M. Vaughan; H. Wänke; A. W. Ward; G. R. Wilson; R. L. Kirk; J. M. Knudsen; S. Larsen; M. T. Lemmon; M. B. Madsen; J. A. Magalhães; J. N. Maki; M. C. Malin; R. M. Manning; J. Matijevic; H. Y. McSween

    1999-01-01

    Mars Pathfinder successfully landed at Ares Vallis on July 4, 1997, deployed and navigated a small rover about 100 m clockwise around the lander, and collected data from three science instruments and ten technology experiments. The mission operated for three months and returned 2.3 Gbits of data, including over 16,500 lander and 550 rover images, 16 chemical analyses of rocks

  7. Imager for Mars Pathfinder experiment (IMP): a multispectral stereo imaging system

    Microsoft Academic Search

    Peter H. Smith

    1998-01-01

    On Independence Day 1997 Mars Pathfinder bounced to a stop on the Ares-Tiu Vallis floodplain and began returning the first pictures from the surface of Mars in 20 years. The IMP camera took panoramas first in a stowed position (about seated height) and after day 2 from a deployed height of 1.85 m (about standing height). The eye separation of

  8. Nicotinic Receptors Mediate Changes in Spinal Motoneuron Development and Axonal Pathfinding in Embryonic Zebrafish

    E-print Network

    Tullos, Desiree

    Nicotinic Receptors Mediate Changes in Spinal Motoneuron Development and Axonal Pathfinding in Embryonic Zebrafish Exposed to Nicotine Kurt R. Svoboda,1,2 Sukumar Vijayaraghavan,2 and Robert L. Tanguay3 that transient exposure of embryonic zebrafish to nicotine delays the development of secondary spinal motoneu

  9. Martian and terrestrial dust devils: Test of a scaling theory using Pathfinder data

    Microsoft Academic Search

    Nilton O. Rennó; Amelia Ann Nash; Jonathan Lunine; James Murphy

    2000-01-01

    The Mars Pathfinder meteorological station recorded wind, pressure, and temperature fluctuations that have been interpreted as dust devils: warm-core vortices that form at the bottom of convective plumes. We apply a scaling theory [Rennó et al., 1998], developed to explain terrestrial dust devil observations, to test the validity of this interpretation and to provide a simple physical interpretation of the

  10. Single-neuron axonal pathfinding under geometric guidance: low-dose-methylmercury developmental neurotoxicity test.

    PubMed

    Wei, Lina; Sweeney, Andrew J; Sheng, Liyuan; Fang, Yu; Kindy, Mark S; Xi, Tingfei; Gao, Bruce Z

    2014-09-21

    Because the nervous system is most vulnerable to toxicants during development, there is a crucial need for a highly sensitive developmental-neurotoxicity-test model to detect potential toxicants at low doses. We developed a lab-on-chip wherein single-neuron axonal pathfinding under geometric guidance was created using soft lithography and laser cell-micropatterning techniques. After coating the surface with L1, an axon-specific member of the Ig family of cell adhesion molecules (CAMs), and optimizing microunit geometric parameters, we introduced low-dose methylmercury, a well-known, environmentally significant neurotoxicant, in the shared medium. Its developmental neurotoxicity was evaluated using a novel axonal pathfinding assay including axonal turning and branching rates at turning points in this model. Compared to the conventional neurite-outgrowth assay, this model's detection threshold for low-dose methylmercury was 10-fold more sensitive at comparable exposure durations. These preliminary results support study of developmental effects of known and potential neurotoxicants on axon pathfinding. This novel assay model would be useful to study neuronal disease mechanisms at the single-cell level. To our knowledge, the potential of methylmercury chloride to cause acute in vitro developmental neurotoxicity (DNT) at such a low dosage has not been reported. This is the first DNT test model with high reproducibility to use single-neuron axonal pathfinding under precise geometric guidance. PMID:25041816

  11. A Strategy to Characterize the LISA-Pathfinder Cold Gas Thruster System

    NASA Astrophysics Data System (ADS)

    Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Brandt, N.; Bursi, A.; Caleno, M.; Cavalleri, A.; Cesarini, A.; Cruise, M.; Danzmann, K.; Diepholz, I.; Dolesi, R.; Dunbar, N.; Ferraioli, L.; Ferroni, V.; Fitzsimons, E.; Freschi, M.; Gallegos, J.; Garcia Marirrodriga, C.; Gerndt, R.; Gesa, L. I.; Gibert, F.; Giardini, D.; Giusteri, R.; Grimani, C.; Harrison, I.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hueller, M.; Huesler, J.; Inchauspé, H.; Jennrich, O.; Jetzer, P.; Johlander, B.; Karnesis, N.; Kaune, B.; Korsakova, N.; Killow, C.; Lloro, I.; Maarschalkerweerd, R.; Madden, S.; Mance, D.; Martin, V.; Martin-Porqueras, F.; Mateos, I.; McNamara, P.; Mendes, J.; Mendes, L.; Moroni, A.; Nofrarias, M.; Paczkowski, S.; Perreur-Lloyd, M.; Petiteau, A.; Pivato, P.; Plagnol, E.; Prat, P.; Ragnit, U.; Ramos-Castro, J.; Reiche, J.; Romera Perez, J. A.; Robertson, D.; Rozemeijer, H.; Russano, G.; Sarra, P.; Schleicher, A.; Slutsky, J.; Sopuerta, C. F.; Sumner, T.; Texier, D.; Thorpe, J.; Trenkel, C.; Tu, H. B.; Vitale, S.; Wanner, G.; Ward, H.; Waschke, S.; Wass, P.; Wealthy, D.; Wen, S.; Weber, W.; Wittchen, A.; Zanoni, C.; Ziegler, T.; Zweifel, P.

    2015-05-01

    The cold gas micro-propulsion system that will be used during the LISA-Pathfinder mission will be one of the most important component used to ensure the "free-fall" of the enclosed test masses. In this paper we present a possible strategy to characterize the effective direction and amplitude gain of each of the 6 thrusters of this system.

  12. The CCD imager electronics for the Mars pathfinder and Mars surveyor cameras

    Microsoft Academic Search

    J. Rainer Kramm; Nicolas Thomas; H. Uwe Keller; Peter H. Smith

    1998-01-01

    The Mars pathfinder stereo camera and both cameras on the Mars surveyor lander use CCD detectors for image acquisition. The frame transfer type CCD's were produced by Loral for space applications under contract from MPAE. A detector consists of two sections of 256 lines and 512 columns each. Pixels in the image section contain an anti-blooming structure to remove excessive

  13. The atmosphere structure and meteorology instrument on the Mars Pathfinder lander

    Microsoft Academic Search

    Alvin Seiff; James E. Tillman; James R. Murphy; John T. Schofield; David Crisp; Jeffrey R. Barnes; Clayton LaBaw; Colin Mahoney; John D. Mihalov; Gregory R. Wilson; Robert Haberle

    1997-01-01

    An instrument on the Pathfinder lander has been designed to measure the structure of Mars' atmosphere during spacecraft entry and descent from ~150km altitude to the surface, and to measure meteorological parameters after landing for the landed duration of the mission. This is specified to be nominally 30 Mars days but potentially up to 1 Earth year. Landed sensors will

  14. Re-creating missing population baselines for Pacific reef sharks.

    PubMed

    Nadon, Marc O; Baum, Julia K; Williams, Ivor D; McPherson, Jana M; Zgliczynski, Brian J; Richards, Benjamin L; Schroeder, Robert E; Brainard, Russell E

    2012-06-01

    Sharks and other large predators are scarce on most coral reefs, but studies of their historical ecology provide qualitative evidence that predators were once numerous in these ecosystems. Quantifying density of sharks in the absence of humans (baseline) is, however, hindered by a paucity of pertinent time-series data. Recently researchers have used underwater visual surveys, primarily of limited spatial extent or nonstandard design, to infer negative associations between reef shark abundance and human populations. We analyzed data from 1607 towed-diver surveys (>1 ha transects surveyed by observers towed behind a boat) conducted at 46 reefs in the central-western Pacific Ocean, reefs that included some of the world's most pristine coral reefs. Estimates of shark density from towed-diver surveys were substantially lower (<10%) than published estimates from surveys along small transects (<0.02 ha), which is not consistent with inverted biomass pyramids (predator biomass greater than prey biomass) reported by other researchers for pristine reefs. We examined the relation between the density of reef sharks observed in towed-diver surveys and human population in models that accounted for the influence of oceanic primary productivity, sea surface temperature, reef area, and reef physical complexity. We used these models to estimate the density of sharks in the absence of humans. Densities of gray reef sharks (Carcharhinus amblyrhynchos), whitetip reef sharks (Triaenodon obesus), and the group "all reef sharks" increased substantially as human population decreased and as primary productivity and minimum sea surface temperature (or reef area, which was highly correlated with temperature) increased. Simulated baseline densities of reef sharks under the absence of humans were 1.1-2.4/ha for the main Hawaiian Islands, 1.2-2.4/ha for inhabited islands of American Samoa, and 0.9-2.1/ha for inhabited islands in the Mariana Archipelago, which suggests that density of reef sharks has declined to 3-10% of baseline levels in these areas. PMID:22536842

  15. Juvenile coral reef fish use sound to locate habitats

    NASA Astrophysics Data System (ADS)

    Radford, C. A.; Stanley, J. A.; Simpson, S. D.; Jeffs, A. G.

    2011-06-01

    There is limited knowledge of the orientation cues used by reef fish in their movement among different habitats, especially those cues used during darkness. Although acoustic cues have been found to be important for settlement-stage fish as they seek settlement habitats, only a small number of studies support the possible role of acoustic cues in the orientation of post-settled and adult reef fish. Therefore, the aim of this study was to determine whether habitat-specific acoustic cues were involved in the nocturnal movements of juvenile reef fish to small experimental patch reefs that were broadcasting sound previously recorded from different habitats (Fringing Reef, Lagoon, Silent). Juvenile fish arriving at each patch reef were caught the next morning by divers and were identified. There were a greater number of occasions when juvenile fish (from all species together) moved onto the patch reefs broadcasting Fringing Reef and Lagoon sound (43 and 38%, respectively) compared to Silent reefs (19%) (?2 = 33.5; P < 0.05). There were significantly more occasions when juvenile fish from the family Nemipteridae were attracted to the patch reefs broadcasting Lagoon sound (63%) versus those reefs broadcasting either Fringing Reef sound (31%) or Silent (6%). In contrast, there were more occasions when juveniles from the family Pomacentridae were attracted to the patch reefs broadcasting Fringing Reef sound (56%) than either Lagoon (24%) or Silent patch reefs (20%) (?2 = 19.5; P < 0.05). These results indicate that some juvenile fish use specific habitat sounds to guide their nocturnal movements. Therefore, the fish are able to not only use the directional information contained in acoustic cues, but can also interpret the content of the acoustic signals for relevant habitat information which is then used in their decision-making for orientation.

  16. Forecasting decadal changes in sea surface temperatures and coral bleaching within a Caribbean coral reef

    NASA Astrophysics Data System (ADS)

    Li, Angang; Reidenbach, Matthew A.

    2014-09-01

    Elevated sea surface temperature (SST) caused by global warming is one of the major threats to coral reefs. While increased SST has been shown to negatively affect the health of coral reefs by increasing rates of coral bleaching, how changes to atmospheric heating impact SST distributions, modified by local flow environments, has been less understood. This study aimed to simulate future water flow patterns and water surface heating in response to increased air temperature within a coral reef system in Bocas del Toro, Panama, located within the Caribbean Sea. Water flow and SST were modeled using the Delft3D-FLOWcomputer simulation package. Locally measured physical parameters, including bathymetry, astronomic tidal forcing, and coral habitat distribution were input into the model and water flow, and SST was simulated over a four-month period under present day, as well as projected warming scenarios in 2020s, 2050s, and 2080s. Changes in SST, and hence the thermal stress to corals, were quantified by degree heating weeks. Results showed that present-day reported bleaching sites were consistent with localized regions of continuous high SST. Regions with highest SST were located within shallow coastal sites adjacent to the mainland or within the interior of the bay, and characterized by low currents with high water retention times. Under projected increases in SSTs, shallow reef areas in low flow regions were found to be hot spots for future bleaching.

  17. Ecology of artificial reefs in the subtropics.

    PubMed

    Shin, Paul K S; Cheung, Siu Gin; Tsang, Tsui Yun; Wai, Ho Yin

    2014-01-01

    The application of artificial reefs (ARs) has a long history, and there is a wealth of information related to the design and performance of ARs in coastal and ocean waters worldwide. However, relatively fewer studies in the literature are focused on the response of benthic communities within the reef areas than those on fish attraction and fish production and on the settlement and colonization of epibiota on the AR structures, especially in the subtropics where seasonal differences and environmental conditions can be large. Recent advances in the understanding of the ecology of ARs in the subtropics are highlighted, with a focus on fish attraction versus fish production, development of epibiota on AR systems and responses of in situ benthic communities in the reef areas. Data are also presented on studies of trophic relationships in subtropical AR systems, and further research areas using analyses of biological traits, stable isotope signatures and fatty acid profiles in investigating the ecology of ARs are proposed. PMID:24981732

  18. Development of a field test environment for the validation of coastal remote sensing algorithms: Enrique Reef, Puerto Rico

    Microsoft Academic Search

    James A. Goodman; Miguel Vélez-Reyes; Shawn Hunt; Roy Armstrong

    2006-01-01

    Remote sensing is increasingly being used as a tool to quantitatively assess the location, distribution and relative health of coral reefs and other shallow aquatic ecosystems. As the use of this technology continues to grow and the analysis products become more sophisticated, there is an increasing need for comprehensive ground truth data as a means to assess the algorithms being

  19. CORAL DISEASE & HEALTH CONSORTIUM: FINDING SOLUTIONS

    EPA Science Inventory

    The National Oceanic Atmospheric Administration (NOAA), the Environmental Protection Agency (EPA), and the Department of Interior (DOI) developed the framework for a Coral Disease and Health Consortium (CDHC) for the United States Coral Reef Task Force (USCRTF) through an interag...

  20. Rock Abrasion on Mars: Clues from the Pathfinder and Viking Landing Sites

    NASA Technical Reports Server (NTRS)

    Bridges, N. T.; Parker, T. J.; Kramer, G. M.

    2000-01-01

    A significant discovery of the Mars Pathfinder (MPF) mission was that many rocks exhibit characteristics of ventifacts, rocks that have been sculpted by saltating particles. Diagnostic features identifying the rocks as ventifacts am elongated pits, flutes, and grooves (collectively referred to as "flutes" unless noted otherwise). Faceted rocks or rock portions, circular pits, rills, and possibly polished rock surfaces are also seen and could be due, to aeolian abrasion. Many of these features were initially identified in rover images, where spatial resolution generally exceeded that of the IMP (Imager for Mars Pathfinder) camera. These images had two major limitations: 1) Only a limited number of rocks were viewed by the rover, biasing flute statistics; and 2) The higher resolution obtained by the rover images and the lack of such pictures at the Viking landing sites hampered comparisons of rock morphologies between the Pathfinder and Viking sites. To avoid this problem, rock morphology and ventifact statistics have been examined using new "super-resolution" IMP and Viking Lander images. Analyses of these images show that: 1) Flutes are seen on about 50% or more of the rocks in the near field at the MPF site; 2) The orientation of these flutes is similar to that for flutes identified in rover images; and 3) Ventifacts are significantly more abundant at the Pathfinder landing site than at the two Viking Landing sites, where rocks have undergone only a limited amount of aeolian abrasion. This is most likely due to the ruggedness of the Pathfinder site and a greater supply of abrading particles available shortly after the Arcs and Tiu Valles outflow channel floods.

  1. Predicting the Location and Spatial Extent of Submerged Coral Reef Habitat in the Great Barrier Reef World Heritage Area, Australia

    PubMed Central

    Bridge, Tom; Beaman, Robin; Done, Terry; Webster, Jody

    2012-01-01

    Aim Coral reef communities occurring in deeper waters have received little research effort compared to their shallow-water counterparts, and even such basic information as their location and extent are currently unknown throughout most of the world. Using the Great Barrier Reef as a case study, habitat suitability modelling is used to predict the distribution of deep-water coral reef communities on the Great Barrier Reef, Australia. We test the effectiveness of a range of geophysical and environmental variables for predicting the location of deep-water coral reef communities on the Great Barrier Reef. Location Great Barrier Reef, Australia. Methods Maximum entropy modelling is used to identify the spatial extent of two broad communities of habitat-forming megabenthos phototrophs and heterotrophs. Models were generated using combinations of geophysical substrate properties derived from multibeam bathymetry and environmental data derived from Bio-ORACLE, combined with georeferenced occurrence records of mesophotic coral communities from autonomous underwater vehicle, remotely operated vehicle and SCUBA surveys. Model results are used to estimate the total amount of mesophotic coral reef habitat on the GBR. Results Our models predict extensive but previously undocumented coral communities occurring both along the continental shelf-edge of the Great Barrier Reef and also on submerged reefs inside the lagoon. Habitat suitability for phototrophs is highest on submerged reefs along the outer-shelf and the deeper flanks of emergent reefs inside the GBR lagoon, while suitability for heterotrophs is highest in the deep waters along the shelf-edge. Models using only geophysical variables consistently outperformed models incorporating environmental data for both phototrophs and heterotrophs. Main Conclusion Extensive submerged coral reef communities that are currently undocumented are likely to occur throughout the Great Barrier Reef. High-quality bathymetry data can be used to identify these reefs, which may play an important role in resilience of the GBR ecosystem to climate change. PMID:23118952

  2. Fiji's largest marine reserve benefits reef sharks

    NASA Astrophysics Data System (ADS)

    Goetze, J. S.; Fullwood, L. A. F.

    2013-03-01

    To provide more information about whether sharks benefit from no-take marine reserves, we quantified the relative abundance and biomass of reef sharks inside and outside of Namena, Fiji's largest reserve (60.6 km2). Using stereo baited remote underwater video systems (stereo-BRUVs), we found that the abundance and biomass of sharks was approximately two and four times greater in shallow and deep locations, respectively, within the Namena reserve compared to adjacent fished areas. The greater abundance and biomass of reef sharks inside Namena is likely a result of greater prey availability rather than protection from fishing. This study demonstrates that marine reserves can benefit sharks.

  3. Reefing Line Tension in CPAS Main Parachute Clusters

    NASA Technical Reports Server (NTRS)

    Ray, Eric S.

    2013-01-01

    Reefing lines are an essential feature to manage inflation loads. During each Engineering Development Unit (EDU) test of the Capsule Parachute Assembly System (CPAS), a chase aircraft is staged to be level with the cluster of Main ringsail parachutes during the initial inflation and reefed stages. This allows for capturing high-quality still photographs of the reefed skirt, suspension line, and canopy geometry. The over-inflation angles are synchronized with measured loads data in order to compute the tension force in the reefing line. The traditional reefing tension equation assumes radial symmetry, but cluster effects cause the reefed skirt of each parachute to elongate to a more elliptical shape. This effect was considered in evaluating multiple parachutes to estimate the semi-major and semi-minor axes. Three flight tests are assessed, including one with a skipped first stage, which had peak reefing line tension over three times higher than the nominal parachute disreef sequence.

  4. Coral reef metabolism and carbon chemistry dynamics of a coral reef flat

    NASA Astrophysics Data System (ADS)

    Albright, Rebecca; Benthuysen, Jessica; Cantin, Neal; Caldeira, Ken; Anthony, Ken

    2015-05-01

    Global carbon emissions continue to acidify the oceans, motivating growing concern for the ability of coral reefs to maintain net positive calcification rates. Efforts to develop robust relationships between coral reef calcification and carbonate parameters such as aragonite saturation state (?arag) aim to facilitate meaningful predictions of how reef calcification will change in the face of ocean acidification. Here we investigate natural trends in carbonate chemistry of a coral reef flat over diel cycles and relate these trends to benthic carbon fluxes by quantifying net community calcification and net community production. We find that, despite an apparent dependence of calcification on ?arag seen in a simple pairwise relationship, if the dependence of net calcification on net photosynthesis is accounted for, knowing ?arag does not add substantial explanatory value. This suggests that, over short time scales, the control of ?arag on net calcification is weak relative to factors governing net photosynthesis.

  5. Conservation and Management Applications of the Reef Volunteer Fish Monitoring Program

    Microsoft Academic Search

    Christy V. Pattengill-Semmens; Brice X. Semmens

    2003-01-01

    The REEF Fish Survey Project is a volunteer fish monitoring program developed by the Reef Environmental Education Foundation (REEF). REEF volunteers collect fish distribution and abundance data using a standardized visual method during regular diving and snorkeling activities. Survey data are recorded on preprinted data sheets that are returned to REEF and optically digitized. Data are housed in a publicly

  6. Coral Reefs: An English Compilation of Activities for Middle School Students.

    ERIC Educational Resources Information Center

    Walker, Sharon H.; Newton, R. Amanda; Ortiz, Alida

    This activity book on coral reefs for middle school students is divided into 10 sections. Section 1 contains the introduction. Section 2 describes what coral reefs are while section 3 describes how coral reefs reproduce and grow. Section 4 discusses where coral reefs are found and section 5 describes life on a coral reef. Section 6 discusses the…

  7. Encouraging Proximal Relations: Queensland High School Students Go to the Reef

    ERIC Educational Resources Information Center

    Stepath, Carl; Whitehouse, Hilary

    2006-01-01

    Background: This article concerns learning with high school students and the effect of snorkeling and coral reef monitoring at the Great Barrier Reef, Australia. The effectiveness of classroom learning, student-reef relationships and reef trips were investigated. Purpose: This paper presents selected student accounts of reef educational…

  8. In Situ Coral Reef Oxygen Metabolism: An Eddy Correlation Study

    PubMed Central

    Long, Matthew H.; Berg, Peter; de Beer, Dirk; Zieman, Joseph C.

    2013-01-01

    Quantitative studies of coral reefs are challenged by the three-dimensional hard structure of reefs and the high spatial variability and temporal dynamics of their metabolism. We used the non-invasive eddy correlation technique to examine respiration and photosynthesis rates, through O2 fluxes, from reef crests and reef slopes in the Florida Keys, USA. We assessed how the photosynthesis and respiration of different reef habitats is controlled by light and hydrodynamics. Numerous fluxes (over a 0.25 h period) were as high as 4500 mmol O2 m?2 d?1, which can only be explained by efficient light utilization by the phototrophic community and the complex canopy structure of the reef, having a many-fold larger surface area than its horizontal projection. Over diel cycles, the reef crest was net autotrophic, whereas on the reef slope oxygen production and respiration were balanced. The autotrophic nature of the shallow reef crests implies that the export of organics is an important source of primary production for the larger area. Net oxygen production on the reef crest was proportional to the light intensity, up to 1750 µmol photons m?2 s?1 and decreased thereafter as respiration was stimulated by high current velocities coincident with peak light levels. Nighttime respiration rates were also stimulated by the current velocity, through enhanced ventilation of the porous framework of the reef. Respiration rates were the highest directly after sunset, and then decreased during the night suggesting that highly labile photosynthates produced during the day fueled early-night respiration. The reef framework was also important to the acquisition of nutrients as the ambient nitrogen stock in the water had sufficient capacity to support these high production rates across the entire reef width. These direct measurements of complex reefs systems yielded high metabolic rates and dynamics that can only be determined through in situ, high temporal resolution measurements. PMID:23536798

  9. Vertical and horizontal distributions of coral-reef fish larvae in open water immediately prior to reef colonization.

    PubMed

    Lecchini, D; Waqalevu, V P; Holles, S; Lerohellec, M; Brie, C; Simpson, S D

    2013-06-01

    To explore the vertical and horizontal distributions of fish larvae near the end of their pelagic period, six light traps were set up over four lunar months at different depths (sub-surface, midwater and bottom) and different habitat types (reef slope: 50 m horizontal distance from the reef crest; frontier zone: 110 m horizontal distance; sandy zone: 200 m horizontal distance) on the outer reef slope of Moorea Island, French Polynesia. The highest captures were in sub-surface traps on the reef slope and the frontier zone, and in bottom traps on the sandy zone and the frontier zone. It is hypothesized that fish larvae move towards the surface near the reef slope to avoid reef-based planktivores and to get into a favourable position for surfing over the reef crest. PMID:23731158

  10. Lab 5: Trouble in Paradise: Factors that Impact Coral Health

    NSDL National Science Digital Library

    In the previous lab, students explored the characteristics of the ocean environment in which coral reefs thrive. Unfortunately,there are a number of factors, both natural and anthropogenic (resulting from human activities), that can alter the ocean environment and threaten the health of coral reef ecosystems. In this activity, students will examine the three main factors that disrupt corals.

  11. Diving down the reefs? Intensive diving tourism threatens the reefs of the northern Red Sea.

    PubMed

    Hasler, Harald; Ott, Jörg A

    2008-10-01

    Intensive recreational SCUBA diving threatens coral reef ecosystems. The reefs at Dahab, South Sinai, Egypt, are among the world's most dived (>30,000 dives y(-1)). We compared frequently dived sites to sites with no or little diving. Benthic communities and condition of corals were examined by the point intercept sampling method in the reef crest zone (3m) and reef slope zone (12 m). Additionally, the abundance of corallivorous and herbivorous fish was estimated based on the visual census method. Sediments traps recorded the sedimentation rates caused by SCUBA divers. Zones subject to intensive SCUBA diving showed a significantly higher number of broken and damaged corals and significantly lower coral cover. Reef crest coral communities were significantly more affected than those of the reef slope: 95% of the broken colonies were branching ones. No effect of diving on the abundance of corallivorous and herbivorous fish was evident. At heavily used dive sites, diver-related sedimentation rates significantly decreased with increasing distance from the entrance, indicating poor buoyancy regulation at the initial phase of the dive. The results show a high negative impact of current SCUBA diving intensities on coral communities and coral condition. Corallivorous and herbivorous fishes are apparently not yet affected, but are endangered if coral cover decline continues. Reducing the number of dives per year, ecologically sustainable dive plans for individual sites, and reinforcing the environmental education of both dive guides and recreational divers are essential to conserve the ecological and the aesthetic qualities of these dive sites. PMID:18701118

  12. Bioethical Consideration in the Search for Bioactive Compounds from Reef`s Invertebrates

    NASA Astrophysics Data System (ADS)

    Sukarmi, Ocky; Radjasa, Karna

    The occurrence of large scale of bioactive compounds is not common to all living organisms, but restricted to certain taxonomic groups. Among marine animals, reef`s invertebrates are the most prolific producers of secondary metabolites and have become sources of great interest to natural product chemistry, since they provide a large proportion of bioactive compounds with different biological activities. Perhaps the most significant problem that has hampered the investigation of secondary metabolites is their low concentration. In marine invertebrates many highly active compounds contribute to < 10-6% of the body-wet weight. Providing sufficient amounts of these biologically active substances, hence, may be a difficult task. In addition, it has often proven extremely difficult and some cases impossible, to provide from invertebrates sufficient amounts of many of these substances due to limited amounts found in the producing organism, or to limited quantity of the organism itself, or to geographic, seasonal or sexual variations in the amounts and in the nature of produced secondary metabolites. There has an increasing concerns regarding the collecting reef`s organisms for the discovery and development of pharmaceuticals since it has been perceived variously as sustaining and threatening conservation. There is an urgent need to take into account the bioethical considerations in anticipating the potential consequences of these activities and proposing management options for sustainable use of reef`s invertebrates as the sources of bioactive compounds.

  13. Last interglacial reef growth beneath Belize barrier and isolated platform reefs

    USGS Publications Warehouse

    Gischler, Eberhard; Lomando, Anthony J.; Hudson, J. Harold; Holmes, Charles W.

    2000-01-01

    We report the first radiometric dates (thermal-ionization mass spectrometry) from late Pleistocene reef deposits from offshore Belize, the location of the largest modern reef complex in the Atlantic Ocean. The results presented here can be used to explain significant differences in bathymetry, sedimentary facies, and reef development of this major reef area, and the results are significant because they contribute to the knowledge of the regional geology of the eastern Yucatán. The previously held concept of a neotectonically stable eastern Yucatán is challenged. The dates indicate that Pleistocene reefs and shallow-water limestones, which form the basement of modern reefs in the area, accumulated ca. 125–130 ka. Significant differences in elevation of the samples relative to present sea level (>10 m) have several possible causes. Differential subsidence along a series of continental margin fault blocks in combination with variation in karstification are probably the prime causes. Differential subsidence is presumably related to initial extension and later left-lateral movements along the adjacent active boundary between the North American and Caribbean plates. Increasing dissolution toward the south during Pleistocene sea-level lowstands is probably a consequence of higher precipitation rates in mountainous southern Belize.

  14. Geomorphology and community structure of Middle Reef, central Great Barrier Reef, Australia: an inner-shelf turbid zone reef subject to episodic mortality events

    NASA Astrophysics Data System (ADS)

    Browne, N. K.; Smithers, S. G.; Perry, C. T.

    2010-09-01

    Middle Reef is an inshore turbid zone reef located 4 km offshore from Townsville, Queensland, Australia. The reef consists of four current-aligned, interconnected reef patches that have reached sea level and formed reef flats. It is regularly exposed to high turbidity (up to 50 mg l-1) generated by wave-driven sediment resuspension or by episodic flood plumes. Middle Reef has a high mean hard coral cover (>39%), relatively low mean macro-algal cover (<15%) and a coral community comprising at least 81 hard coral species. Cluster analysis differentiated six benthic communities which were mapped onto the geomorphological structure of the reef to reveal a spatially patchy community mosaic that reflects hydrodynamic and sediment redistribution processes. Coral cover data collected annually from windward slope transects since 1993 show that coral cover has increased over the last ~15 years despite a history of episodic mortality events. Although episodic mortality may be interpreted as an indication of marginality, over decadal timescales, Middle Reef has recovered rapidly following mortality events and is clearly a resilient coral reef.

  15. Correspondence and Least Squares Analyses of Soil and Rock Compositions for the Viking Lander 1 and Pathfinder Sites

    NASA Technical Reports Server (NTRS)

    Larsen, K. W.; Arvidson, R. E.; Jolliff, B. L.; Clark, B. C.

    2000-01-01

    Correspondence and Least Squares Mixing Analysis techniques are applied to the chemical composition of Viking 1 soils and Pathfinder rocks and soils. Implications for the parent composition of local and global materials are discussed.

  16. Widespread prevalence of cryptic Symbiodinium D in the key Caribbean reef builder, Orbicella annularis

    NASA Astrophysics Data System (ADS)

    Kennedy, Emma V.; Foster, Nicola L.; Mumby, Peter J.; Stevens, Jamie R.

    2015-06-01

    Symbiodinium D, a relatively rare clade of algal endosymbiont with a global distribution, has attracted interest as some of its sub-cladal types induce increased thermal tolerance and associated trade-offs, including reduced growth rate in its coral hosts. Members of Symbiodinium D are increasingly reported to comprise low-abundance `cryptic' (<10 %) proportions of mixed coral endosymbiont communities, with unknown ecological implications. Real-time PCR (RT-PCR) targeted to specific types is sufficiently sensitive to detect these background symbiont levels. In this study, RT-PCR was employed to screen 552 colonies of the key Caribbean reef builder Orbicella annularis sampled across a 5.4 million km2 range for the presence of cryptic Symbiodinium `D1' (i.e., the principal Caribbean ITS2 variants, D1 and D1-4). All but one out of 33 populations analysed were shown to host low abundances of Symbiodinium D1, with an average of >30 % of corals per site found to harbour the symbiont. When the same samples were analysed using the conventional screening technique, denaturing gradient gel electrophoresis, Symbiodinium D1 was only detected in 12 populations and appeared to be hosted by <12 % of colonies where present (in agreement with other reported low prevalence/absences in O. annularis). Cryptic Symbiodinium D1 showed a mainly uniform distribution across the wider Caribbean region, although significantly more Mesoamerican Barrier Reef corals hosted cryptic Symbiodinium D1 than might be expected by chance, possibly as a consequence of intense warming in the region in 1998. Widespread prevalence of thermally tolerant Symbiodinium in O. annularis may potentially reflect a capacity for the coral to temporarily respond to warming events through symbiont shuffling. However, association with reduced coral calcification means that the ubiquitous nature of Symbiodinium D1 in O. annularis populations is unlikely to prevent long-term declines in reef health, at a time when maintaining reef growth is vital to sustain reef ecosystem function.

  17. Modelling Coral Reef Futures to Inform Management: Can Reducing Local-Scale Stressors Conserve Reefs under Climate Change?

    PubMed Central

    Gurney, Georgina G.; Melbourne-Thomas, Jessica; Geronimo, Rollan C.; Aliño, Perry M.; Johnson, Craig R.

    2013-01-01

    Climate change has emerged as a principal threat to coral reefs, and is expected to exacerbate coral reef degradation caused by more localised stressors. Management of local stressors is widely advocated to bolster coral reef resilience, but the extent to which management of local stressors might affect future trajectories of reef state remains unclear. This is in part because of limited understanding of the cumulative impact of multiple stressors. Models are ideal tools to aid understanding of future reef state under alternative management and climatic scenarios, but to date few have been sufficiently developed to be useful as decision support tools for local management of coral reefs subject to multiple stressors. We used a simulation model of coral reefs to investigate the extent to which the management of local stressors (namely poor water quality and fishing) might influence future reef state under varying climatic scenarios relating to coral bleaching. We parameterised the model for Bolinao, the Philippines, and explored how simulation modelling can be used to provide decision support for local management. We found that management of water quality, and to a lesser extent fishing, can have a significant impact on future reef state, including coral recovery following bleaching-induced mortality. The stressors we examined interacted antagonistically to affect reef state, highlighting the importance of considering the combined impact of multiple stressors rather than considering them individually. Further, by providing explicit guidance for management of Bolinao's reef system, such as which course of management action will most likely to be effective over what time scales and at which sites, we demonstrated the utility of simulation models for supporting management. Aside from providing explicit guidance for management of Bolinao's reef system, our study offers insights which could inform reef management more broadly, as well as general understanding of reef systems. PMID:24260347

  18. Cross-shore velocity shear, eddies and heterogeneity in water column properties over fringing coral reefs: West Maui, Hawaii

    USGS Publications Warehouse

    Storlazzi, C.D.; McManus, M.A.; Logan, J.B.; McLaughlin, B.E.

    2006-01-01

    A multi-day hydrographic survey cruise was conducted to acquire spatially extensive, but temporally limited, high-resolution, three-dimensional measurements of currents, temperature, salinity and turbidity off West Maui in the summer of 2003 to better understand coastal dynamics along a complex island shoreline with coral reefs. These data complement long-term, high-resolution tide, wave, current, temperature, salinity and turbidity measurements made at a number of fixed locations in the study area starting in 2001. Analyses of these hydrographic data, in conjunction with numerous field observations, evoke the following conceptual model of water and turbidity flux along West Maui. Wave- and wind-driven flows appear to be the primary control on flow over shallower portions of the reefs while tidal and subtidal currents dominate flow over the outer portions of the reefs and insular shelf. When the direction of these flows counter one another, which is quite common, they cause a zone of cross-shore horizontal shear and often form a front, with turbid, lower-salinity water inshore of the front and clear, higher-salinity water offshore of the front. It is not clear whether these zones of high shear and fronts are the cause or the result of the location of the fore reef, but they appear to be correlated alongshore over relatively large horizontal distances (orders of kilometers). When two flows converge or when a single flow is bathymetrically steered, eddies can be generated that, in the absence of large ocean surface waves, tend to accumulate material. Areas of higher turbidity and lower salinity tend to correlate with regions of poor coral health or the absence of well-developed reefs, suggesting that the oceanographic processes that concentrate and/or transport nutrients, contaminants, low-salinity water or suspended sediment might strongly influence coral reef ecosystem health and sustainability.

  19. Diurnal warming in shallow coastal seas: Observations from the Caribbean and Great Barrier Reef regions

    NASA Astrophysics Data System (ADS)

    Zhu, X.; Minnett, P. J.; Berkelmans, R.; Hendee, J.; Manfrino, C.

    2014-07-01

    A good understanding of diurnal warming in the upper ocean is important for the validation of satellite-derived sea surface temperature (SST) against in-situ buoy data and for merging satellite SSTs taken at different times of the same day. For shallow coastal regions, better understanding of diurnal heating could also help improve monitoring and prediction of ecosystem health, such as coral reef bleaching. Compared to its open ocean counterpart which has been studied extensively and modeled with good success, coastal diurnal warming has complicating localized characteristics, including coastline geometry, bathymetry, water types, tidal and wave mixing. Our goal is to characterize coastal diurnal warming using two extensive in-situ temperature and weather datasets from the Caribbean and Great Barrier Reef (GBR), Australia. Results showed clear daily warming patterns in most stations from both datasets. For the three Caribbean stations where solar radiation is the main cause of daily warming, the mean diurnal warming amplitudes were about 0.4 K at depths of 4-7 m and 0.6-0.7 K at shallower depths of 1-2 m; the largest warming value was 2.1 K. For coral top temperatures of the GBR, 20% of days had warming amplitudes >1 K, with the largest >4 K. The bottom warming at shallower sites has higher daily maximum temperatures and lower daily minimum temperatures than deeper sites nearby. The averaged daily warming amplitudes were shown to be closely related to daily average wind speed and maximum insolation, as found in the open ocean. Diurnal heating also depends on local features including water depth, location on different sections of the reef (reef flat vs. reef slope), the relative distance from the barrier reef chain (coast vs. lagoon stations vs. inner barrier reef sites vs. outer rim sites); and the proximity to the tidal inlets. In addition, the influence of tides on daily temperature changes and its relative importance compared to solar radiation was quantified by calculating the ratio of power spectrum densities at the principal lunar semidiurnal M2 tide versus 24-hour cycle frequency representing mainly solar radiation forcing, i.e., (PSDM2/PSD24). Despite the fact that GBR stations are generally located at regions with large tidal changes, the tidal effects were modest: 80% of stations showed value of (PSDM2/PSD24) of less than 10%.

  20. CORAL REEF RESPONSES TO GLOBAL CLIMATE CHANGE

    EPA Science Inventory

    Increased emissions of greenhouse gases and synthetic compounds are related to rising sea temperatures and increased penetration of ultraviolet radiation (UVR), two factors that are consistently linked to bleaching and disease of corals. Coral reefs play a major role in the envir...

  1. Applying MCSST to coral reef bleaching

    Microsoft Academic Search

    M. W. Gleeson; A. E. Strong

    1995-01-01

    In the 1980s and early 1990s, coral reef bleaching events of unprecedented frequency and global extent were observed. Elevated water temperature is suspected as the primary causal stress of mass bleaching events from this period. The relationship between sea surface temperatures (SSTs) and coral bleaching events was investigated using National Oceanic and Atmospheric Administration (NOAA) Multi-Channel Sea Surface Temperature (MCSST)

  2. Introduction Worldwide reef fish fisheries are in

    E-print Network

    and JUAN J. AGAR and Eklund, 1999). Reef fish species, especially groupers, are particularly vulnerable@rsmas.miami.edu), and Juan J. Agar is with the Social Science Research Group, Southeast Fisheries Science Center, National Marine Fisheries Service, NOAA, Miami, FL 33149 (email: Juan.Agar@noaa.gov). ABSTRACT

  3. Reef Corals of Fanning Island I

    Microsoft Academic Search

    J. E. MARAGOS

    Recent surveys indicate that the diversity of reef corals at Fanning Island is greater than previously estimated. Most of the approximately 70 species belonging to 32 genera and subgenera typically are found in one of three environ­ ments. A turbid lagoon fauna has high abundance but lower diversity of pre­ dominantly branching forms. The clear lagoon coral fauna has both

  4. Dust deposition at the Mars Pathfinder landing site: observations and modeling of visible\\/near-infrared spectra

    Microsoft Academic Search

    Jeffrey R. Johnson; William M. Grundy; Mark T. Lemmon

    2003-01-01

    Temporal variations in the visible\\/near-infrared reflectance spectra of the radiometric calibration targets on the Mars Pathfinder (MPF) lander obtained by the Imager for Mars Pathfinder (IMP) camera reveal the effects of aeolian dust deposition at the MPF site throughout the mission. Sky brightness models in combination with two-layer radiative transfer models were used with these data to track changes in

  5. Calcification by reef-building sclerobionts.

    PubMed

    Mallela, Jennie

    2013-01-01

    It is widely accepted that deteriorating water quality associated with increased sediment stress has reduced calcification rates on coral reefs. However, there is limited information regarding the growth and development of reef building organisms, aside from the corals themselves. This study investigated encruster calcification on five fore-reefs in Tobago subjected to a range of sedimentation rates (1.2 to 15.9 mg cm(-2) d(-1)). Experimental substrates were used to assess rates of calcification in sclerobionts (e.g. crustose coralline algae, bryozoans and barnacles) across key reef microhabitats: cryptic (low-light), exposed (open-horizontal) and vertical topographic settings. Sedimentation negatively impacted calcification by photosynthesising crustose coralline algae in exposed microhabitats and encrusting foram cover (%) in exposed and cryptic substrates. Heterotrophs were not affected by sedimentation. Fore-reef, turbid water encruster assemblages calcified at a mean rate of 757 (SD ±317) g m(-2) y(-1). Different microhabitats were characterised by distinct calcareous encruster assemblages with different rates of calcification. Taxa with rapid lateral growth dominated areal cover but were not responsible for the majority of CaCO3 production. Cryptobiont assemblages were composed of a suite of calcifying taxa which included sciaphilic cheilostome bryozoans and suspension feeding barnacles. These calcified at mean rates of 20.1 (SD ±27) and 4.0 (SD ±3.6) g m(-2) y(-1) respectively. Encruster cover (%) on exposed and vertical substrates was dominated by crustose coralline algae which calcified at rates of 105.3 (SD ±67.7) g m(-2) y(-1) and 56.3 (SD ±8.3) g m(-2) y(-1) respectively. Globally, encrusting organisms contribute significant amounts of carbonate to the reef framework. These results provide experimental evidence that calcification rates, and the importance of different encrusting organisms, vary significantly according to topography and sediment impacts. These findings also highlight the need for caution when modelling reef framework accretion and interpreting results which extrapolate information from limited data. PMID:23555864

  6. Fishing down the largest coral reef fish species.

    PubMed

    Fenner, Douglas

    2014-07-15

    Studies on remote, uninhabited, near-pristine reefs have revealed surprisingly large populations of large reef fish. Locations such as the northwestern Hawaiian Islands, northern Marianas Islands, Line Islands, U.S. remote Pacific Islands, Cocos-Keeling Atoll and Chagos archipelago have much higher reef fish biomass than islands and reefs near people. Much of the high biomass of most remote reef fish communities lies in the largest species, such as sharks, bumphead parrots, giant trevally, and humphead wrasse. Some, such as sharks and giant trevally, are apex predators, but others such as bumphead parrots and humphead wrasse, are not. At many locations, decreases in large reef fish species have been attributed to fishing. Fishing is well known to remove the largest fish first, and a quantitative measure of vulnerability to fishing indicates that large reef fish species are much more vulnerable to fishing than small fish. The removal of large reef fish by fishing parallels the extinction of terrestrial megafauna by early humans. However large reef fish have great value for various ecological roles and for reef tourism. PMID:24889317

  7. The Role of Turtles as Coral Reef Macroherbivores

    PubMed Central

    Goatley, Christopher H. R.; Hoey, Andrew S.; Bellwood, David R.

    2012-01-01

    Herbivory is widely accepted as a vital function on coral reefs. To date, the majority of studies examining herbivory in coral reef environments have focused on the roles of fishes and/or urchins, with relatively few studies considering the potential role of macroherbivores in reef processes. Here, we introduce evidence that highlights the potential role of marine turtles as herbivores on coral reefs. While conducting experimental habitat manipulations to assess the roles of herbivorous reef fishes we observed green turtles (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata) showing responses that were remarkably similar to those of herbivorous fishes. Reducing the sediment load of the epilithic algal matrix on a coral reef resulted in a forty-fold increase in grazing by green turtles. Hawksbill turtles were also observed to browse transplanted thalli of the macroalga Sargassum swartzii in a coral reef environment. These responses not only show strong parallels to herbivorous reef fishes, but also highlight that marine turtles actively, and intentionally, remove algae from coral reefs. When considering the size and potential historical abundance of marine turtles we suggest that these potentially valuable herbivores may have been lost from many coral reefs before their true importance was understood. PMID:22768189

  8. Status of the glass sponge reefs in the Georgia Basin.

    PubMed

    Cook, Sarah E; Conway, Kim W; Burd, Brenda

    2008-12-01

    The purpose of this paper is to describe the status and general faunal composition of sponge reefs in the Georgia Basin (GB), British Columbia, Canada. Fourteen distinct deep-water glass sponge (Hexactinellid) reefs have been mapped using multibeam bathymetry and sidescan sonar in the GB. Seven of these have been surveyed visually using video from remotely operated vehicles (ROVs). Analysis of video data indicated that three reefs were undamaged, two were damaged and the other two were damaged but potentially recovering. The nature of the damaged reefs, with large areas of scattered dead sponge skeleton fragments and few live reef-building sponges (Aphrocallistes vastus and Heterochone calyx), as well as video evidence of tracks suggest they were damaged mechanically by mobile fishing gear. Relative abundance of the megafauna associated with the reefs is discussed in the context of oceanographic conditions, such as sediment accumulation and organic flux, as well as overall reef status. Of particular interest for fisheries conservation efforts in the area was the fact that one undamaged reef in the southern GB showed higher taxonomic richness and abundance of rockfish (Sebastes spp.), both adult and juvenile, compared to an adjacent damaged reef. This result suggests that undamaged reefs may act as refugia for these endangered stocks. PMID:18954900

  9. The wicked problem of China's disappearing coral reefs.

    PubMed

    Hughes, Terry P; Huang, Hui; Young, Matthew A L

    2013-04-01

    We examined the development of coral reef science and the policies, institutions, and governance frameworks for management of coral reefs in China in order to highlight the wicked problem of preserving reefs while simultaneously promoting human development and nation building. China and other sovereign states in the region are experiencing unprecedented economic expansion, rapid population growth, mass migration, widespread coastal development, and loss of habitat. We analyzed a large, fragmented literature on the condition of coral reefs in China and the disputed territories of the South China Sea. We found that coral abundance has declined by at least 80% over the past 30 years on coastal fringing reefs along the Chinese mainland and adjoining Hainan Island. On offshore atolls and archipelagos claimed by 6 countries in the South China Sea, coral cover has declined from an average of >60% to around 20% within the past 10-15 years. Climate change has affected these reefs far less than coastal development, pollution, overfishing, and destructive fishing practices. Ironically, these widespread declines in the condition of reefs are unfolding as China's research and reef-management capacity are rapidly expanding. Before the loss of corals becomes irreversible, governance of China's coastal reefs could be improved by increasing public awareness of declining ecosystem services, by providing financial support for training of reef scientists and managers, by improving monitoring of coral reef dynamics and condition to better inform policy development, and by enforcing existing regulations that could protect coral reefs. In the South China Sea, changes in policy and legal frameworks, refinement of governance structures, and cooperation among neighboring countries are urgently needed to develop cooperative management of contested offshore reefs. PMID:23140101

  10. Two waves of colonization straddling the K–Pg boundary formed the modern reef fish fauna

    E-print Network

    Price, S. A.; Schmitz, L.; Oufiero, C. E.; Eytan, R. I.; Dornburg, A.; Smith, William Leo; Friedman, M.; Near, T. J.; Wainwright, P. C.

    2014-05-22

    reef fishes. We find that reef lineages successively colonized reef habitats throughout the Late Cretaceous and early Palaeogene. Two waves of invasion were accompanied by increasing morphological convergence: one in the Late Cretaceous from 90 to 72 Ma...

  11. 76 FR 24050 - Coral Reef Restoration Plan, Final Programmatic Environmental Impact Statement, Biscayne National...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-29

    ...National Park Service [2310-0003-422] Coral Reef Restoration Plan, Final Programmatic...Environmental Impact Statement for the Coral Reef Restoration Plan, Biscayne National...Environmental Impact Statement for the Coral Reef Restoration Plan (Plan/FEIS)...

  12. 78 FR 66683 - Fisheries in the Western Pacific; Special Coral Reef Ecosystem Fishing Permit

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-06

    ...Fisheries in the Western Pacific; Special Coral Reef Ecosystem Fishing Permit AGENCY...significant impact for the issuance of a special coral reef ecosystem fishing permit...SUMMARY: NMFS issued a Special Coral Reef Ecosystem Fishing Permit that...

  13. 75 FR 21650 - Coral Reef Restoration Plan, Draft Programmatic Environmental Impact Statement, Biscayne National...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-26

    ...DEPARTMENT OF THE INTERIOR National Park Service Coral Reef Restoration Plan, Draft Programmatic...Environmental Impact Statement for the Coral Reef Restoration Plan, Biscayne National...Environmental Impact Statement (DEIS) for the Coral Reef Restoration Plan for Biscayne...

  14. 76 FR 77779 - Availability of Seats for the Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve Advisory...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-14

    ...Seats for the Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve Advisory Council...seats on the Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve Advisory Council...SUPPLEMENTARY INFORMATION: The NWHI Coral Reef Ecosystem Reserve is a [[Page...

  15. 77 FR 48504 - Proposed Information Collection; Comment Request; Economic Value of Puerto Rico's Coral Reef...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-14

    ...Request; Economic Value of Puerto Rico's Coral Reef Ecosystems for Recreation-Tourism...non-market economic values of Puerto Rico's coral reef ecosystems. Estimates will be made...recreation-tourism for all of Puerto Rico's coral reef ecosystems. The required...

  16. 77 FR 12567 - Proposed Information Collection; Comment Request; Pacific Islands Region Coral Reef Ecosystems...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-01

    ...Comment Request; Pacific Islands Region Coral Reef Ecosystems Logbook and Reporting AGENCY...U.S. citizen issued with, a Special Coral Reef Ecosystem Fishing Permit (authorized under the Fishery Management Plan for Coral Reef Ecosystems of the Western...

  17. 76 FR 38618 - Proposed Information Collection; Comment Request; Coral Reef Conservation Program Survey

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-01

    ...Information Collection; Comment Request; Coral Reef Conservation Program Survey AGENCY...States (U.S.) jurisdictions containing coral reefs. Specifically, NOAA is seeking...related to the communities affected by coral reef conservation programs. The...

  18. 77 FR 16211 - Availability of Seats for the Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve Advisory...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-20

    ...Seats for the Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve Advisory Council...seats on the Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve Advisory Council...SUPPLEMENTARY INFORMATION: The NWHI Coral Reef Ecosystem Reserve is a marine...

  19. Predation Risk, Resource Quality, and Reef Structural Complexity Shape Territoriality in a Coral Reef Herbivore

    PubMed Central

    Gunn, Bridgette K.; Kelley, Megan C.

    2015-01-01

    For many species securing territories is important for feeding and reproduction. Factors such as competition, habitat availability, and male characteristics can influence an individual’s ability to establish and maintain a territory. The risk of predation can have an important influence on feeding and reproduction; however, few have studied its effect on territoriality. We investigated territoriality in a haremic, polygynous species of coral reef herbivore, Sparisoma aurofrenatum (redband parrotfish), across eight reefs in the Florida Keys National Marine Sanctuary that were either protected or unprotected from fishing of piscivorous fishes. We examined how territory size and quality varied with reef protection status, competition, predation risk, and male size. We then determined how territory size and quality influenced harem size and female size to understand the effect of territoriality on reproductive potential. We found that protected reefs trended towards having more large predatory fishes and that territories there were smaller but had greater algal nutritional quality relative to unprotected reefs. Our data suggest that even though males in protected sites have smaller territories, which support fewer females, they may improve their reproductive potential by choosing nutritionally rich areas, which support larger females. Thus, reef protection appears to shape the trade-off that herbivorous fishes make between territory size and quality. Furthermore, we provide evidence that males in unprotected sites, which are generally less complex than protected sites, choose territories with higher structural complexity, suggesting the importance of this type of habitat for feeding and reproduction in S. aurofrenatum. Our work argues that the loss of corals and the resulting decline in structural complexity, as well as management efforts to protect reefs, could alter the territory dynamics and reproductive potential of important herbivorous fish species. PMID:25714431

  20. Review of the trajectory and atmospheric structure reconstruction for Mars Pathfinder

    NASA Astrophysics Data System (ADS)

    Withers, Paul; Towner, Martin; Hathi, Brijen; Zarnecki, John

    2004-02-01

    Mars Pathfinder landed on Mars on July 4, 1997. It used a novel deceleration procedure, consisting of a hypersonic aeroshell, a transonic parachute, retro-rockets, and airbags, to reach the surface safely. Its aerodynamic properties passively maintained a near-zero angle of attack throughout its entry. There were no gyroscopes to monitor attitude. Several different trajectory reconstructions have been based on the assumptions that accelerations along its symmetry axis are directed along its flight path and that accelerations in other directions are insignificant. The aerodynamics of Pathfinder once its parachute opened are still not well-understood and the available observations are probably not sufficient to improve matters significantly in the future.

  1. Time domain maximum likelihood parameter estimation in LISA Pathfinder Data Analysis

    E-print Network

    Congedo, G; Hueller, M; De Marchi, F; Vitale, S; Armano, M; Hewitson, M; Nofrarias, M

    2011-01-01

    LISA is the upcoming space-based Gravitational Wave telescope. LISA Pathfinder, to be launched in the coming years, will prove and verify the detection principle of the fundamental Doppler link of LISA on a flight hardware identical in design to that of LISA. LISA Pathfinder will collect a picture of all noise disturbances possibly affecting LISA, achieving the unprecedented pureness of geodesic motion necessary for the detection of gravitational waves. The first steps of both missions will crucially depend on a very precise calibration of the key system parameters. Moreover, robust parameters estimation is of fundamental importance in the correct assessment of the residual force noise, an essential part of the data processing for LISA. In this paper we present a maximum likelihood parameter estimation technique in time domain being devised for this calibration and show its proficiency on simulated data and validation through Monte Carlo realizations of independent noise runs. We discuss its robustness to non...

  2. Macroalgae Decrease Growth and Alter Microbial Community Structure of the Reef-Building Coral, Porites astreoides

    PubMed Central

    Vega Thurber, Rebecca; Burkepile, Deron E.; Correa, Adrienne M. S.; Thurber, Andrew R.; Shantz, Andrew A.; Welsh, Rory; Pritchard, Catharine; Rosales, Stephanie

    2012-01-01

    With the continued and unprecedented decline of coral reefs worldwide, evaluating the factors that contribute to coral demise is of critical importance. As coral cover declines, macroalgae are becoming more common on tropical reefs. Interactions between these macroalgae and corals may alter the coral microbiome, which is thought to play an important role in colony health and survival. Together, such changes in benthic macroalgae and in the coral microbiome may result in a feedback mechanism that contributes to additional coral cover loss. To determine if macroalgae alter the coral microbiome, we conducted a field-based experiment in which the coral Porites astreoides was placed in competition with five species of macroalgae. Macroalgal contact increased variance in the coral-associated microbial community, and two algal species significantly altered microbial community composition. All macroalgae caused the disappearance of a ?-proteobacterium previously hypothesized to be an important mutualist of P. astreoides. Macroalgal contact also triggered: 1) increases or 2) decreases in microbial taxa already present in corals, 3) establishment of new taxa to the coral microbiome, and 4) vectoring and growth of microbial taxa from the macroalgae to the coral. Furthermore, macroalgal competition decreased coral growth rates by an average of 36.8%. Overall, this study found that competition between corals and certain species of macroalgae leads to an altered coral microbiome, providing a potential mechanism by which macroalgae-coral interactions reduce coral health and lead to coral loss on impacted reefs. PMID:22957055

  3. The Results of Dynamic Data Acquisition During Mars Pathfinder Prototype Airbag Drop Testing

    NASA Technical Reports Server (NTRS)

    Davis, Gregory L.

    1996-01-01

    The Mars Pathfinder mission, scheduled for launch in December 1996, will use an airbag system to safely deliver a lander to the Martian surface.The airbag landing system has undergone a comprehensive test program during its evolution from initial design phase to final qualification and acceptance testing. This paper outlines the test approach used in the airbag development program, describes the data acquisition system used to obtain and evaluate airbag performance data, and presents test results.

  4. Rocks and aeolian features in the Mars Pathfinder landing site region: Viking infrared thermal mapper observations

    Microsoft Academic Search

    Kenneth S. Edgett; Philip R. Christensen

    1997-01-01

    Albedo, rock abundance, and thermal inertia derived from Viking infrared thermal mapper observations provide information about the surface materials within the Mars Pathfinder landing ellipse in Ares Vallis. Relative to the rest of Mars, the site has an intermediate albedo (0.19-0.23), intermediate-to-high bulk thermal inertia (410-540 J m -2 s -ø's K-), and high rock abundance (18-25%). At local scales

  5. General circulation model simulations of the Mars Pathfinder atmospheric structure investigation\\/meteorology data

    Microsoft Academic Search

    Robert M. Haberle; Manoj M. Joshi; James R. Murphy; Jeffrey R. Barnes; John T. Schofield; Greg Wilson; Miguel Lopez-Valverde; Jeffery L. Hollingsworth; Alison F. C. Bridger; James Schaeffer

    1999-01-01

    The NASA Ames Mars General Circulation Model is used to interpret selected results from the Mars Pathfinder atmospheric structure instrument\\/meteorology (ASI\\/MET) experiment. The present version of the model has an improved soil thermal model, a new boundary layer scheme, and a correction for non-local thermodynamic equilibrium effects at solar wavelengths. We find good agreement with the ASI\\/MET entry data if

  6. Artificial reef observations from a manned submersible off southeast Florida

    USGS Publications Warehouse

    Shinn, E.A.; Wicklund, R.I.

    1989-01-01

    Examination of 16 artificial reef structures in depths ranging from 30-120m indicated that the highest numbers of fish are found around reefs in water shallower than 46m. Fewer fish, especially those with tropical coral reef affinities, <46m was probably caused by a thermocline. Algae and reef community encrusters, abundant on shallower structures, were absent below 46m. Structures that penetrated above the thermocline, such as upright oil rigs and a hopper barge, were also effective reefs. The open structure and high profile of the rigs enhance their use as artificial reefs by providing a range of well-aerated habitats. Greatest diversity and numbers of fish were observed at the Miami sewer outfall. -from Authors

  7. Frictional wave dissipation on a remarkably rough reef

    NASA Astrophysics Data System (ADS)

    Monismith, Stephen G.; Rogers, Justin S.; Koweek, David; Dunbar, Robert B.

    2015-05-01

    We present a week of observations of wave dissipation on the south forereef of Palmyra Atoll. Using wave measurements made in 6.2 m and 11.2 m of water offshore of the surf zone, we computed energy fluxes and near-bottom velocity. Equating the divergence of the shoreward energy flux to its dissipation by bottom friction and parameterizating dissipation in terms of the root-mean-square velocity cubed, we find that the wave friction factor, fw, for this reef is 1.80 ± 0.07, nearly an order of magnitude larger than values previously found for reefs. We attribute this remarkably high value of fw to the complex canopy structure of the reef, which we believe may be characteristic of healthy reefs. This suggests that healthy reefs with high coral cover may provide greater coastal protection than do degraded reefs with low coral cover.

  8. Structural and compositional characterization of the adhesive produced by reef building oysters.

    PubMed

    Alberts, Erik M; Taylor, Stephen D; Edwards, Stephanie L; Sherman, Debra M; Huang, Chia-Ping; Kenny, Paul; Wilker, Jonathan J

    2015-04-29

    Oysters have an impressive ability to overcome difficulties of life within the stressful intertidal zone. These shellfish produce an adhesive for attaching to each other and building protective reef communities. With their reefs often exceeding kilometers in length, oysters play a major role in balancing the health of coastal marine ecosystems. Few details are available to describe oyster adhesive composition or structure. Here several characterization methods were applied to describe the nature of this material. Microscopy studies indicated that the glue is comprised of organic fiber-like and sheet-like structures surrounded by an inorganic matrix. Phospholipids, cross-linking chemistry, and conjugated organics were found to differentiate this adhesive from the shell. Symbiosis in material synthesis could also be present, with oysters incorporating bacterial polysaccharides into their adhesive. Oyster glue shows that an organic-inorganic composite material can provide adhesion, a property especially important when constructing a marine ecosystem. PMID:25843147

  9. Climate change affects key nitrogen-fixing bacterial populations on coral reefs.

    PubMed

    Santos, Henrique F; Carmo, Flávia L; Duarte, Gustavo; Dini-Andreote, Francisco; Castro, Clovis B; Rosado, Alexandre S; van Elsas, Jan Dirk; Peixoto, Raquel S

    2014-11-01

    Coral reefs are at serious risk due to events associated with global climate change. Elevated ocean temperatures have unpredictable consequences for the ocean's biogeochemical cycles. The nitrogen cycle is driven by complex microbial transformations, including nitrogen fixation. This study investigated the effects of increased seawater temperature on bacteria able to fix nitrogen (diazotrophs) that live in association with the mussid coral Mussismilia harttii. Consistent increases in diazotroph abundances and diversities were found at increased temperatures. Moreover, gradual shifts in the dominance of particular diazotroph populations occurred as temperature increased, indicating a potential future scenario of climate change. The temperature-sensitive diazotrophs may provide useful bioindicators of the effects of thermal stress on coral reef health, allowing the impact of thermal anomalies to be monitored. In addition, our findings support the development of research on different strategies to improve the fitness of corals during events of thermal stress, such as augmentation with specific diazotrophs. PMID:24830827

  10. Overview of the development of the pathfinder ultra-long duration balloon system

    NASA Astrophysics Data System (ADS)

    Said, Magdi A.; Stuchlik, David; Corbin, Brian; Smolinski, Michael; Abresch, Brian; Shreves, Christopher; Stancil, Robert; Cathey, Henry M.; Cannon, Scott

    2004-01-01

    The ultra-long duration balloon (ULDB) Pathfinder Project is developing a small pumpkin balloon system and a new communication package based on the iridium satellites technology to demonstrate a global, 100-day duration capability that is scalable to the full-scale ULDB. A set of trade studies has been conducted to determine the volume, mass and cost of the balloon system to support up to 90 kg payload mass to an altitude of 35 km. The Pathfinder test balloons will provide valuable data in the development of performance models for future ULDB flights. The iridium based communication package will include a power subsystem, a command and data-handling unit, a GPS receiver, and an iridium L-Band Transceiver (LBT) for global communications. The flight data will include, at a minimum: latitude, longitude, altitude, horizontal and vertical speeds, heading, time, and other balloon performance parameters (i.e., system voltages, temperatures, etc.). Although the system will be designed for global launch capability, initial flights will be launched from the proposed full-scale ULDB mission launch locations. This paper will present and discuss the initial series of trade studies conducted for the development of the pathfinder balloon and the design concept of the iridium based communication package.

  11. Improving Bayesian analysis for LISA Pathfinder using an efficient Markov Chain Monte Carlo method

    NASA Astrophysics Data System (ADS)

    Ferraioli, Luigi; Porter, Edward K.; Armano, Michele; Audley, Heather; Congedo, Giuseppe; Diepholz, Ingo; Gibert, Ferran; Hewitson, Martin; Hueller, Mauro; Karnesis, Nikolaos; Korsakova, Natalia; Nofrarias, Miquel; Plagnol, Eric; Vitale, Stefano

    2014-02-01

    We present a parameter estimation procedure based on a Bayesian framework by applying a Markov Chain Monte Carlo algorithm to the calibration of the dynamical parameters of the LISA Pathfinder satellite. The method is based on the Metropolis-Hastings algorithm and a two-stage annealing treatment in order to ensure an effective exploration of the parameter space at the beginning of the chain. We compare two versions of the algorithm with an application to a LISA Pathfinder data analysis problem. The two algorithms share the same heating strategy but with one moving in coordinate directions using proposals from a multivariate Gaussian distribution, while the other uses the natural logarithm of some parameters and proposes jumps in the eigen-space of the Fisher Information matrix. The algorithm proposing jumps in the eigen-space of the Fisher Information matrix demonstrates a higher acceptance rate and a slightly better convergence towards the equilibrium parameter distributions in the application to LISA Pathfinder data. For this experiment, we return parameter values that are all within ˜1 ? of the injected values. When we analyse the accuracy of our parameter estimation in terms of the effect they have on the force-per-unit of mass noise, we find that the induced errors are three orders of magnitude less than the expected experimental uncertainty in the power spectral density.

  12. Estimating Discharge from Ares Vallis Using Pathfinder Images and MOLA Topography

    NSDL National Science Digital Library

    Eric Grosfils

    On July 4th, 1997, Mars Pathfinder landed at the mouth of Ares Vallis, a large channel that drains into the Chryse Planitia basin. While there remains a great deal to debate about the origin of the channels, one of the leading hypotheses at present is the idea that these features are the result of catastrophic flooding. If this is correct, then the plains where Pathfinder landed may be rich in debris eroded out of the Martian highlands across which the Ares Vallis channel passes, providing a golden combinationa relatively safe landing site which still provides access to a wide variety of different rock types. [If you would like to learn more about the many Pathfinder results, explore the April, 1999 and January, 2000 issues of the Journal of Geophysical ResearchPlanets (the green one) in the library.] For the sake of this lab assignment you will hypothesize that the Ares Vallis and associated deposits were indeed produced by catastrophic flooding, and will use the information at your disposal to learn all you can about the putative flooding event.

  13. Estimating Discharge from Ares Vallis Using Pathfinder Images and MOLA Topography

    NSDL National Science Digital Library

    Eric Grosfils

    On July 4th, 1997, Mars Pathfinder landed at the mouth of Ares Vallis, a large channel that drains into the Chryse Planitia basin. While there remains a great deal to debate about the origin of the channels, one of the leading hypotheses at present is the idea that these features are the result of catastrophic flooding. If this is correct, then the plains where Pathfinder landed may be rich in debris eroded out of the Martian highlands across which the Ares Vallis channel passes, providing a golden combinationâa relatively safe landing site which still provides access to a wide variety of different rock types. [If you would like to learn more about the many Pathfinder results, explore the April, 1999 and January, 2000 issues of the journal Journal of Geophysical ResearchâPlanets (the green one) in the library.] For the sake of this lab assignment you will hypothesize that the Ares Vallis and associated deposits were indeed produced by catastrophic flooding, and will use the information at your disposal to learn all you can about the putative flooding event.

  14. Macroalgal herbivory on recovering versus degrading coral reefs

    NASA Astrophysics Data System (ADS)

    Chong-Seng, K. M.; Nash, K. L.; Bellwood, D. R.; Graham, N. A. J.

    2014-06-01

    Macroalgal-feeding fishes are considered to be a key functional group on coral reefs due to their role in preventing phase shifts from coral to macroalgal dominance, and potentially reversing the shift should it occur. However, assessments of macroalgal herbivory using bioassay experiments are primarily from systems with relatively high coral cover. This raises the question of whether continued functionality can be ensured in degraded systems. It is clearly important to determine whether the species that remove macroalgae on coral-dominated reefs will still be present and performing significant algal removal on macroalgal-dominated reefs. We compared the identity and effectiveness of macroalgal-feeding fishes on reefs in two conditions post-disturbance—those regenerating with high live coral cover (20-46 %) and those degrading with high macroalgal cover (57-82 %). Using filmed Sargassum bioassays, we found significantly different Sargassum biomass loss between the two conditions; mean assay weight loss due to herbivory was 27.9 ± 4.9 % on coral-dominated reefs and 2.2 ± 1.1 % on reefs with high macroalgal cover. However, once standardised for the availability of macroalgae on the reefs, the rates of removal were similar between the two reef conditions (4.8 ± 4.1 g m-2 h-1 on coral-dominated and 5.3 ± 2.1 g m-2 h-1 on macroalgal-dominated reefs). Interestingly, the Sargassum-assay consumer assemblages differed between reef conditions; nominally grazing herbivores, Siganus puelloides and Chlorurus sordidus, and the browser , Siganus sutor, dominated feeding on high coral cover reefs, whereas browsing herbivores, Naso elegans, Naso unicornis, and Leptoscarus vaigiensis, prevailed on macroalgal-dominated reefs. It appeared that macroalgal density in the surrounding habitat had a strong influence on the species driving the process of macroalgal removal. This suggests that although the function of macroalgal removal may continue, the species responsible may change with context, differing between systems that are regenerating versus degrading.

  15. Coral Reefs 1 Assignment for next class meeting

    E-print Network

    Mitchell, Randall J.

    /C-intro.htm Coral Bleaching 1/11/201110 http://www.science.widener.edu/~grant/esa/tiee/issues/coral/coralCoral Reefs 1 Assignment for next class meeting Activate your CPS clicker OR contact me to get to an example in class Coral Reefs 1/11/20113 http://www.geology.iupui.edu/academics/CLASSES/g130/reefs/EO.htm 1

  16. Factors controlling holocene reef growth: An interdisciplinary approach

    Microsoft Academic Search

    Wolf-Christian Dullo; Marcos Gektidis; Stjepko Golubic; Georg A. Heiss; Heike Kampmann; William Kiene; Dieter K. Kroll; Martin L. Kuhrau; Gudrun Radtke; John G. Reijmer; Götz B. Reinicke; Dietrich Schlichter; Helmut Schuhmacher; Klaus Vogel

    1995-01-01

    Summary  This interim report deals with investigations on key factors controlling reef growth by zoophysiologists, ecologists, paleontologists\\u000a and geologists. The different levels of emphasis are the coral animal and the reef community. The main study area is the Red\\u000a Sea which reaches over 20C latitude up to the northernmost margin of the global coral reef belt. Supplementary results on\\u000a microborer ecology

  17. Quantifying climatological ranges and anomalies for Pacific coral reef ecosystems.

    PubMed

    Gove, Jamison M; Williams, Gareth J; McManus, Margaret A; Heron, Scott F; Sandin, Stuart A; Vetter, Oliver J; Foley, David G

    2013-01-01

    Coral reef ecosystems are exposed to a range of environmental forcings that vary on daily to decadal time scales and across spatial scales spanning from reefs to archipelagos. Environmental variability is a major determinant of reef ecosystem structure and function, including coral reef extent and growth rates, and the abundance, diversity, and morphology of reef organisms. Proper characterization of environmental forcings on coral reef ecosystems is critical if we are to understand the dynamics and implications of abiotic-biotic interactions on reef ecosystems. This study combines high-resolution bathymetric information with remotely sensed sea surface temperature, chlorophyll-a and irradiance data, and modeled wave data to quantify environmental forcings on coral reefs. We present a methodological approach to develop spatially constrained, island- and atoll-scale metrics that quantify climatological range limits and anomalous environmental forcings across U.S. Pacific coral reef ecosystems. Our results indicate considerable spatial heterogeneity in climatological ranges and anomalies across 41 islands and atolls, with emergent spatial patterns specific to each environmental forcing. For example, wave energy was greatest at northern latitudes and generally decreased with latitude. In contrast, chlorophyll-a was greatest at reef ecosystems proximate to the equator and northern-most locations, showing little synchrony with latitude. In addition, we find that the reef ecosystems with the highest chlorophyll-a concentrations; Jarvis, Howland, Baker, Palmyra and Kingman are each uninhabited and are characterized by high hard coral cover and large numbers of predatory fishes. Finally, we find that scaling environmental data to the spatial footprint of individual islands and atolls is more likely to capture local environmental forcings, as chlorophyll-a concentrations decreased at relatively short distances (>7 km) from 85% of our study locations. These metrics will help identify reef ecosystems most exposed to environmental stress as well as systems that may be more resistant or resilient to future climate change. PMID:23637939

  18. Holocene aggradation of the Dry Tortugas coral reef ecosystem

    Microsoft Academic Search

    J. C. Brock; M. Palaseanu-Lovejoy; R. Z. Poore; A. Nayegandhi; C. W. Wright

    2010-01-01

    Radiometric age dating of reef cores acquired at the Dry Tortugas coral reef ecosystem (DTCRE) was merged with lidar topographic\\u000a mapping to examine Holocene reef development linked to spatial variation in growth and erosion under the control of sea level.\\u000a Analysis of variance of lidar topography confirmed the presence of three distinct terraces on all three major DTCRE banks\\u000a (Loggerhead

  19. Near-future ocean acidification causes differences in microbial associations within diverse coral reef taxa.

    PubMed

    Webster, N S; Negri, A P; Flores, F; Humphrey, C; Soo, R; Botté, E S; Vogel, N; Uthicke, S

    2013-04-01

    Microorganisms form symbiotic partnerships with a diverse range of marine organisms and can be critical to the health and survival of their hosts. Despite the importance of these relationships, the sensitivity of symbiotic microbes to ocean acidification (OA) is largely unknown and this needs to be redressed to adequately predict marine ecosystem resilience in a changing climate. We adopted a profiling approach to explore the sensitivity of microbes associated with coral reef biofilms and representatives of three ecologically important calcifying invertebrate phyla [corals, foraminifera and crustose coralline algae (CCA)] to OA. The experimental design for this study comprised four pHs consistent with current IPCC predictions for the next few centuries (pHNIST 8.1, 7.9, 7.7, 7.5); these pH/pCO? conditions were produced in flow-through aquaria using CO? bubbling. All reduced pH/increased pCO? treatments caused clear differences in the microbial communities associated with coral, foraminifera, CCA and reef biofilms over 6 weeks, while no visible signs of host stress were detected over this period. The microbial communities of coral, foraminifera, CCA and biofilms were significantly different between pH?8.1 (pCO??=?464??atm) and pH?7.9 (pCO??=?822??atm), a concentration likely to be exceeded by the end of the present century. This trend continued at lower pHs/higher pCO?. 16S rRNA gene sequencing revealed variable and species-specific changes in the microbial communities with no microbial taxa consistently present or absent from specific pH treatments. The high sensitivity of coral, foraminifera, CCA and biofilm microbes to OA conditions projected to occur by 2100 is a concern for reef ecosystems and highlights the need for urgent research to assess the implications of microbial shifts for host health and coral reef processes. PMID:23584968

  20. Reef ecology. Chemically mediated behavior of recruiting corals and fishes: a tipping point that may limit reef recovery.

    PubMed

    Dixson, Danielle L; Abrego, David; Hay, Mark E

    2014-08-22

    Coral reefs are in global decline, converting from dominance by coral to dominance by seaweed. Once seaweeds become abundant, coral recovery is suppressed unless herbivores return to remove seaweeds, and corals then recruit. Variance in the recovery of fishes and corals is not well understood. We show that juveniles of both corals and fishes are repelled by chemical cues from fished, seaweed-dominated reefs but attracted to cues from coral-dominated areas where fishing is prohibited. Chemical cues of specific seaweeds from degraded reefs repulsed recruits, and cues from specific corals that are typical of healthy reefs attracted recruits. Juveniles were present at but behaviorally avoided recruiting to degraded reefs dominated by seaweeds. For recovery, degraded reefs may need to be managed to produce cues that attract, rather than repel, recruiting corals and fishes. PMID:25146281

  1. Miocene reef facies of pelagian block, central Mediterranean

    SciTech Connect

    Pedley, H.M.

    1988-02-01

    Miocene reefs outcrop in the Maltese Islands, southeastern Sicily, and the pelagian island of Lampedusa. Several rapid eustatic sea level fluctuations affected these late Tortonian-early Messinian build-ups; normal salinities appear to have been maintained during these events. In addition to sea floor topography, reef development appears to have been controlled by turbulence. Encruster-dominated patch reefs are typical of platform and shallow ramp situations where turbulence is high. Branching and massive coral assemblages are typical of fore-reef curtains and steep slope substrates.

  2. African and Asian dust: from desert soils to coral reefs

    USGS Publications Warehouse

    Garrison, Virginia H.; Shinn, Eugene A.; Foreman, William T.; Griffin, Dale W.; Holmes, Charles W.; Kellogg, Christina A.; Majewski, Michael S.; Richardson, Laurie L.; Ritchie, Kim B.; Smith, Garriet W.

    2003-01-01

    Many hypotheses have been proposed to explain the decline of coral reefs throughout the world, but none adequately accounts for the lack of recovery of reefs or the wide geographical distribution of coral diseases. The processes driving the decline remain elusive. Hundreds of millions of tons of dust transported annually from Africa and Asia to the Americas may be adversely affecting coral reefs and other downwind ecosystems. Viable microorganisms, macro- and micronutrients, trace metals, and an array of organic contaminants carried in the dust air masses and deposited in the oceans and on land may play important roles in the complex changes occurring on coral reefs worldwide.

  3. Coral reef fish smell leaves to find island homes

    PubMed Central

    Dixson, Danielle L; Jones, Geoffrey P; Munday, Philip L; Planes, Serge; Pratchett, Morgan S; Srinivasan, Maya; Syms, Craig; Thorrold, Simon R

    2008-01-01

    Recent studies have shown that some coral reef fish larvae return to natal reefs, while others disperse to distant reefs. However, the sensory mechanisms used to find settlement sites are poorly understood. One hypothesis is that larvae use olfactory cues to navigate home or find other suitable reef habitats. Here we show a strong association between the clownfish Amphiprion percula and coral reefs surrounding offshore islands in Papua New Guinea. Host anemones and A. percula are particularly abundant in shallow water beneath overhanging rainforest vegetation. A series of experiments were carried out using paired-choice flumes to evaluate the potential role of water-borne olfactory cues in finding islands. Recently settled A. percula exhibited strong preferences for: (i) water from reefs with islands over water from reefs without islands; (ii) water collected near islands over water collected offshore; and (iii) water treated with either anemones or leaves from rainforest vegetation. Laboratory reared-juveniles exhibited the same positive response to anemones and rainforest vegetation, suggesting that olfactory preferences are innate rather than learned. We hypothesize that A. percula use a suite of olfactory stimuli to locate vegetated islands, which may explain the high levels of self-recruitment on island reefs. This previously unrecognized link between coral reefs and island vegetation argues for the integrated management of these pristine tropical habitats. PMID:18755672

  4. Maintenance of fish diversity on disturbed coral reefs

    NASA Astrophysics Data System (ADS)

    Wilson, S. K.; Dolman, A. M.; Cheal, A. J.; Emslie, M. J.; Pratchett, M. S.; Sweatman, H. P. A.

    2009-03-01

    Habitat perturbations play a major role in shaping community structure; however, the elements of disturbance-related habitat change that affect diversity are not always apparent. This study examined the effects of habitat disturbances on species richness of coral reef fish assemblages using annual surveys of habitat and 210 fish species from 10 reefs on the Great Barrier Reef (GBR). Over a period of 11 years, major disturbances, including localised outbreaks of crown-of-thorns sea star ( Acanthaster planci), severe storms or coral bleaching, resulted in coral decline of 46-96% in all the 10 reefs. Despite declines in coral cover, structural complexity of the reef framework was retained on five and species richness of coral reef fishes maintained on nine of the disturbed reefs. Extensive loss of coral resulted in localised declines of highly specialised coral-dependent species, but this loss of diversity was more than compensated for by increases in the number of species that feed on the epilithic algal matrix (EAM). A unimodal relationship between areal coral cover and species richness indicated species richness was greatest at approximately 20% coral cover declining by 3-4 species (6-8% of average richness) at higher and lower coral cover. Results revealed that declines in coral cover on reefs may have limited short-term impact on the diversity of coral reef fishes, though there may be fundamental changes in the community structure of fishes.

  5. No-take areas, herbivory and coral reef resilience.

    PubMed

    Hughes, Terry P; Bellwood, David R; Folke, Carl S; McCook, Laurence J; Pandolfi, John M

    2007-01-01

    Coral reefs worldwide are under threat from various anthropogenic factors, including overfishing and pollution. A new study by Mumby et al. highlights the trophic relationships between humans, carnivorous and herbivorous fishes, and the potential role of no-take areas in maintaining vulnerable coral reef ecosystems. No-take areas, where fishing is prohibited, are vital tools for managing food webs, ecosystem function and the resilience of reefs, in a seascape setting that extends far beyond the boundaries of the reefs themselves. PMID:17070963

  6. Effects of herbivory on zonation of Sargassum spp. within fringing reefs of the central Great Barrier Reef

    Microsoft Academic Search

    L. J. McCook; Townsville MC

    1997-01-01

    A combination of small-scale transplants and herbivore exclusion was used to test the importance of herbivory, physiological\\u000a tolerance limits, and recruitment and dispersal in regulating the distribution and abundance of the genus Sargassum on two nearshore fringing reefs of the central Great Barrier Reef, during 1992\\/1993. Sargassum (predominantly S. oligocystum and S. tenerrimum) were transplanted from reef-flat zones where they

  7. Reef sharks exhibit site-fidelity and higher relative abundance in marine reserves on the Mesoamerican Barrier Reef.

    PubMed

    Bond, Mark E; Babcock, Elizabeth A; Pikitch, Ellen K; Abercrombie, Debra L; Lamb, Norlan F; Chapman, Demian D

    2012-01-01

    Carcharhinid sharks can make up a large fraction of the top predators inhabiting tropical marine ecosystems and have declined in many regions due to intense fishing pressure. There is some support for the hypothesis that carcharhinid species that complete their life-cycle within coral reef ecosystems, hereafter referred to as "reef sharks", are more abundant inside no-take marine reserves due to a reduction in fishing pressure (i.e., they benefit from marine reserves). Key predictions of this hypothesis are that (a) individual reef sharks exhibit high site-fidelity to these protected areas and (b) their relative abundance will generally be higher in these areas compared to fished reefs. To test this hypothesis for the first time in Caribbean coral reef ecosystems we combined acoustic monitoring and baited remote underwater video (BRUV) surveys to measure reef shark site-fidelity and relative abundance, respectively. We focused on the Caribbean reef shark (Carcharhinus perezi), the most common reef shark in the Western Atlantic, at Glover's Reef Marine Reserve (GRMR), Belize. Acoustically tagged sharks (N?=?34) were detected throughout the year at this location and exhibited strong site-fidelity. Shark presence or absence on 200 BRUVs deployed at GRMR and three other sites (another reserve site and two fished reefs) showed that the factor "marine reserve" had a significant positive effect on reef shark presence. We rejected environmental factors or site-environment interactions as predominant drivers of this pattern. These results are consistent with the hypothesis that marine reserves can benefit reef shark populations and we suggest new hypotheses to determine the underlying mechanism(s) involved: reduced fishing mortality or enhanced prey availability. PMID:22412965

  8. Geology Fieldnotes: Capitol Reef National Park, Utah

    NSDL National Science Digital Library

    This Capitol Reef National Park site contains park geology information, park maps, photographs, visitor information, and a teacher feature (resources for teaching geology with National Park examples). Geologic data includes descriptions of the Waterpocket Fold, a monocline formed in the Laramide Orogeny and made of sedimentary rock. Also covered is erosion, and details about the Cathedral Valley outcrop of gypsum. This formation is Permian to Cretaceous in age (270-80 million years old).

  9. Medical hazards of the coral reef.

    PubMed

    Sorokin, M

    1975-01-01

    An account is given of some aspects of poisonings sustained by coming into contact with animals of the coral reefs of the Fiji Islands. Poisonings can be grouped into those in which the toxin is introduced parenterally-envenomings, and those in which it is ingested. Illustrative case histories are presented of injuries from 2 echinoderms and of envenoming from the "deadly" stonefish. A therapeutic approach to puffer-fish poisoning is mentioned and the problem of ciguatera poisoning is outlined. PMID:1170656

  10. Rigs to reefs: a petroleum industry perspective 

    E-print Network

    Dubose, William Perry

    1988-01-01

    artificial reefs can enhance rough bottom habitat, provide quality fishing grounds closer to access areas, and provide benefits to anglers and the economies of shore communities. Carlisle et al. (1964) reports that all fish tend to associate themselves... the number of fish species caught one season before and after the reconstruction. Their data indicate a significant increase in catch for three species in 1947 as compared to 1946. Sea bass reportedly were caught in numbers 25 times greater than...

  11. Ecological speciation in tropical reef fishes

    Microsoft Academic Search

    Luiz A. Rocha; D. Ross Robertson; Joe Roman; Brian W. Bowen

    2005-01-01

    indicating evolutionary processes beyond conventional allopatry. In a survey of mtDNA sequences of five congeneric west Atlantic reef fishes (wrasses, genus Halichoeres) with similar dispersal potential, we observed phylogeographical patterns that contradict expectations of geographical isolation, and instead indicate a role for ecological speciation. In Halichoeres bivittatus and the species pair Halichoeres radiatus\\/brasiliensis, we observed strong partitions (3.4% and 2.3%

  12. Octocoral Species Assembly and Coexistence in Caribbean Coral Reefs

    PubMed Central

    Velásquez, Johanna; Sánchez, Juan A.

    2015-01-01

    Background What are the determinant factors of community assemblies in the most diverse ecosystem in the ocean? Coral reefs can be divided in continental (i.e., reefs that develop on the continental shelf, including siliciclastic reefs) and oceanic (i.e., far off the continental shelf, usually on volcanic substratum); whether or not these habitat differences impose community-wide ecological divergence or species exclusion/coexistence with evolutionary consequences, is unknown. Methods Studying Caribbean octocorals as model system, we determined the phylogenetic community structure in a coral reef community, making emphasis on species coexistence evidenced on trait evolution and environmental feedbacks. Forty-nine species represented in five families constituted the species pool from which a phylogenetic tree was reconstructed using mtDNA. We included data from 11 localities in the Western Caribbean (Colombia) including most reef types. To test diversity-environment and phenotype-environment relationships, phylogenetic community structure and trait evolution we carried out comparative analyses implementing ecological and evolutionary approaches. Results Phylogenetic inferences suggest clustering of oceanic reefs (e.g., atolls) contrasting with phylogenetic overdispersion of continental reefs (e.g., reefs banks). Additionally, atolls and barrier reefs had the highest species diversity (Shannon index) whereas phylogenetic diversity was higher in reef banks. The discriminant component analysis supported this differentiation between oceanic and continental reefs, where continental octocoral species tend to have greater calyx apertures, thicker branches, prominent calyces and azooxanthellate species. This analysis also indicated a clear separation between the slope and the remaining habitats, caused by the presence or absence of Symbiodinium. K statistic analysis showed that this trait is conserved as well as the branch shape. Discussion There was strong octocoral community structure with opposite diversity and composition patterns between oceanic and continental reefs. Even habitats with similar depths and overall environmental conditions did not share similar communities between oceanic and continental reefs. This indicates a strong regional influence over the local communities, probably due to water transparency differences between major reef types, i.e., oceanic vs. continental shelf-neritic. This was supported by contrasting patterns found in morphology, composition and evolutionary history of the species between atolls and reef banks. PMID:26177191

  13. Near-surface enrichment of zooplankton over a shallow back reef: implications for coral reef food webs

    NASA Astrophysics Data System (ADS)

    Alldredge, A. L.; King, J. M.

    2009-12-01

    Zooplankton were 3-8 times more abundant during the day near the surface than elsewhere in the water column over a 1-2.4 m deep back reef in Moorea, French Polynesia. Zooplankton were also significantly more abundant near the surface at night although gradients were most pronounced under moonlight. Zooplankton in a unidirectional current became concentrated near the surface within 2 m of departing a well-mixed trough immediately behind the reef crest, indicating that upward swimming behavior, rather than near-bottom depletion by reef planktivores, was the proximal cause of these gradients. Zooplankton were highly enriched near the surface before and after a full lunar eclipse but distributed evenly throughout the water column during the eclipse itself supporting light as a proximal cue for the upward swimming behavior of many taxa. This is the first investigation of the vertical distribution of zooplankton over a shallow back reef typical of island barrier reef systems common around the world. Previous studies on deeper fringing reefs found zooplankton depletion near the bottom but no enrichment aloft. In Moorea, where seawater is continuously recirculated out the lagoon and back across the reef crest onto the back reef, selection for upward swimming behavior may be especially strong, because the surface serves both as a refuge from predation and an optimum location for retention within the reef system. Planktivorous fish and corals that can forage or grow even marginally higher in the water column might have a substantial competitive advantage over those nearer the bottom on shallow reefs. Zooplankton abundance varied more over a few tens of centimeters vertical distance than it did between seasons or even between day and night indicating that great care must be taken to accurately assess the availability of zooplankton as food on shallow reefs.

  14. Low calcification in corals in the Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Atreyee

    2012-10-01

    Reef-building coral communities in the Great Barrier Reef—the world's largest coral reef—may now be calcifying at only about half the rate that they did during the 1970s, even though live coral cover may not have changed over the past 40 years, a new study finds. In recent decades, coral reefs around the world, home to large numbers of fish and other marine species, have been threatened by such human activities as pollution, overfishing, global warming, and ocean acidification; the latter affects ambient water chemistry and availability of calcium ions, which are critical for coral communities to calcify, build, and maintain reefs. Comparing data from reef surveys during the 1970s, 1980s, and 1990s with present-day (2009) measurements of calcification rates in One Tree Island, a coral reef covering 13 square kilometers in the southern part of the Great Barrier Reef, Silverman et al. show that the total calcification rates (the rate of calcification minus the rate of dissolution) in these coral communities have decreased by 44% over the past 40 years; the decrease appears to stem from a threefold reduction in calcification rates during nighttime.

  15. Oyster reefs can outpace sea-level rise

    NASA Astrophysics Data System (ADS)

    Rodriguez, Antonio B.; Fodrie, F. Joel; Ridge, Justin T.; Lindquist, Niels L.; Theuerkauf, Ethan J.; Coleman, Sara E.; Grabowski, Jonathan H.; Brodeur, Michelle C.; Gittman, Rachel K.; Keller, Danielle A.; Kenworthy, Matthew D.

    2014-06-01

    In the high-salinity seaward portions of estuaries, oysters seek refuge from predation, competition and disease in intertidal areas, but this sanctuary will be lost if vertical reef accretion cannot keep pace with sea-level rise (SLR). Oyster-reef abundance has already declined ~85% globally over the past 100 years, mainly from over harvesting, making any additional losses due to SLR cause for concern. Before any assessment of reef response to accelerated SLR can be made, direct measures of reef growth are necessary. Here, we present direct measurements of intertidal oyster-reef growth from cores and terrestrial lidar-derived digital elevation models. On the basis of our measurements collected within a mid-Atlantic estuary over a 15-year period, we developed a globally testable empirical model of intertidal oyster-reef accretion. We show that previous estimates of vertical reef growth, based on radiocarbon dates and bathymetric maps, may be greater than one order of magnitude too slow. The intertidal reefs we studied should be able to keep up with any future accelerated rate of SLR (ref. ) and may even benefit from the additional subaqueous space allowing extended vertical accretion.

  16. -Congressional Policy Brief -International Year of the Reef 2008

    E-print Network

    strategies to conserve the world's coral reef resources. The ICRI is not a permanent structure action to develop and implement effective management strategies for conservation and sustainable use or organization, but an informal network that aims to catalyze the best strategies to conserve coral reefs

  17. Coral reefs, Kwajalein Atoll, Republic of the Marshall Islands

    USGS Multimedia Gallery

    Underwater image of a wave breaking over a coral reef on Kwajalein Atoll in the Republic of the Marshall Islands. This image shows how the high hydrodynamic roughness of live, healthy corals causes friction that induces breaking of waves over coral reefs, reducing wave energy at the shoreline that c...

  18. Global warming and oil spills could cool shoaling reefs

    SciTech Connect

    Cubit, J.D. (Smithsonian Tropical Research Inst., Apdo (Panama))

    1990-01-09

    High water temperature generated on reef flats have been implicated as one of the factors determining the ecological patterns and structural morphologies peculiar to shoaling reefs. In approximately ten years of water temperature and water level data from a shoaling reef flat at Punta Galeta (Caribbean Panama), water temperatures were dependent on water levels. Water temperatures ranged up to 38[degrees]C when daily minimum water depths over the reef crest were < 12 cm, but never exceeded 30[degrees]C when the minimum water levels were > 12 cm. If conservative predictions of sea level rise caused by global warming are correct, normal vertical accretion rates of the reef flat could keep pace with rising sea level until the middle of the next century; after that the occurrence of high water temperatures would be rapidly reduced. However, damage from an oil spill at Punta Galeta in 1986 was concentrated at the seaward margin of the reef flat, where biogenic processes control the overall vertical accretion of the reef platform. By slowing rates of vertical accretion, oil impact could potentially accelerate the effects of global warming on the ecology and morphology of the reef.

  19. Temperature Dependence of Oxygen18 Concentration in Reef Coral Carbonates

    Microsoft Academic Search

    Jon N. Weber; Peter M. J. Woodhead

    1972-01-01

    Oxygen isotope ratios in the aragonite precipitated by the scleractinian reef-building corals indicate that the skeletal carbonate is not in isotopic equilibrium with the sea water of the reef environment in which the corals grew. Despite this apparent isotopic disequilibrium, values are temperature dependent. The $xsO versus temperature curves for various coral genera are parallel or nearly parallel to the

  20. Aquarium Maintenance of Reef Octocorals Raised from Field Collected Larvae

    Microsoft Academic Search

    D. Gateño; Y. Barki; B. Rinkevich

    2000-01-01

    The development of standardized and sustainable aquaculture techniques for the cultivation of marine organisms offers many advantages: it would help reduce the quantity of living material harvested from coral reefs; it could be used as an efficient means of rehabilitating impoverished reef ecosystems (e.g. by reseeding depleted natural stocks of corals); it would provide an educational and research tool for