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1

The Changing Health of Coral Reefs  

Microsoft Academic Search

Throughout their entire global range coral reefs are in decline. Coral bleaching, macroalgal overgrowth and coral diseases — responses signaling the declining health of coral reefs — have occurred with increasing frequency and intensity in recent decades. Decreased calcification may also be affecting coral reefs over longer time scales. Declines in coral reef health have been attributed to various natural

Richard T. Barber; Anna K. Hilting; Marshall L. Hayes

2001-01-01

2

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

PubMed Central

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

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

2010-01-01

3

Shifting the paradigm of coral-reefhealth’ assessment  

Microsoft Academic Search

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

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

2005-01-01

4

Pathfinder-Plus on flight in Hawaii  

NASA Technical Reports Server (NTRS)

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.

1998-01-01

5

Pathfinder-Plus on flight over Hawaii  

NASA Technical Reports Server (NTRS)

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.

1998-01-01

6

Pathfinder-Plus on flight over Hawaii  

NASA Technical Reports Server (NTRS)

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.

1998-01-01

7

-Congressional Policy Brief -Coral Reefs: For Health, For Wealth, For Life  

E-print Network

- Congressional Policy Brief - Coral Reefs: For Health, For Wealth, For Life Table of Contents Introduction ­ 1 What are Corals and Coral Reefs? ­ 1 Coral Reef Biology ­ 2 Hazards to Coral Reefs ­ 2 Major Reef-building Coral Diseases ­ 3 Coral Bleaching ­ 4 References and Resource Links ­ 4 "The

8

Pathfinder-Plus on a flight in Hawaii  

NASA Technical Reports Server (NTRS)

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.

1998-01-01

9

Pathfinder-Plus takes off on flight in Hawaii  

NASA Technical Reports Server (NTRS)

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.

1998-01-01

10

Pathfinder-Plus on flight over Hawaiian Islands  

NASA Technical Reports Server (NTRS)

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.

1998-01-01

11

TEMPORAL TRENDS IN THE HEALTH OF SOUTH FLORIDA CORAL REEFS  

EPA Science Inventory

Barron, M.G., D.L. Santavy, L. MacLaughlin, E. Mueller, E. Peters, B. Quarles and J. Campbell. In press. Temporal Trends in the Health of South Florida Coral Reefs (Abstract). To be presented at the SETAC Fourth World Congress, 14-18 November 2004, Portland, OR. 1 p. (ERL,GB R100...

12

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

NASA Technical Reports Server (NTRS)

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.

1998-01-01

13

Pathfinder-Plus on flight near Hawaiian island N'ihau  

NASA Technical Reports Server (NTRS)

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.

1998-01-01

14

Pathfinder-Plus on flight over Hawaiian island N'ihau  

NASA Technical Reports Server (NTRS)

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.

1998-01-01

15

Environmental quality and preservation; reefs, corals, and carbonate sands; guides to reef-ecosystem health and environment  

USGS Publications Warehouse

Introduction In recent years, the health of the entire coral reef ecosystem that lines the outer shelf off the Florida Keys has declined markedly. In particular, loss of those coral species that are the building blocks of solid reef framework has significant negative implications for economic vitality of the region. What are the reasons for this decline? Is it due to natural change, or are human activities (recreational diving, ship groundings, farmland runoff, nutrient influx, air-borne contaminants, groundwater pollutants) a contributing factor and if so, to what extent? At risk of loss are biologic resources of the reefs, including habitats for endangered species in shoreline mangroves, productive marine and wetland nurseries, and economic fisheries. A healthy reef ecosystem builds a protective offshore barrier to catastrophic wave action and storm surges generated by tropical storms and hurricanes. In turn, a healthy reef protects the homes, marinas, and infrastructure on the Florida Keys that have been designed to capture a lucrative tourism industry. A healthy reef ecosystem also protects inland agricultural and livestock areas of South Florida whose produce and meat feed much of the United States and other parts of the world. In cooperation with the National Oceanic and Atmospheric Administration's (NOAA) National Marine Sanctuary Program, the U.S. Geological Survey (USGS) continues longterm investigations of factors that may affect Florida's reefs. One of the first steps in distinguishing between natural change and the effects of human activities, however, is to determine how coral reefs have responded to past environmental change, before the advent of man. By so doing, accurate scientific information becomes available for Marine Sanctuary management to understand natural change and thus to assess and regulate potential human impact better. The USGS studies described here evaluate the distribution (location) and historic vitality (thickness) of Holocene reefs in South Florida, relative to type of underlying bedrock morphology, and their varied natural response to rising sea level. These studies also assess movement and accumulation of sands, relative to direction of prevailing energy, and origin of the component sand grains. Geophysical data collected with highresolution sound-wave instruments that provide pictures of the sediment and bedrock are used to interpret sediment thickness. Reef thickness is determined by collecting limestone rock cores by drilling. Drill cores through reefs are used to identify the coral species that built them and to determine how reefs reacted to rising sea level. These data are supplemented by using isotope-dating techniques to derive the carbon-14 (C14) age of the corals and mangrove peat in the cores. Mangrove peat forms in very shallow water and at the shoreline but is found today buried beneath offshore reefs.

Lidz, Barbara H.

2001-01-01

16

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

USGS Publications Warehouse

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.

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

2001-01-01

17

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

NASA Technical Reports Server (NTRS)

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.

1998-01-01

18

Mars Pathfinder  

NSDL National Science Digital Library

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.

Laboratory, Nasa J.

19

Pathfinders: Science  

NSDL National Science Digital Library

The Indianapolis Marion County Public Library provides these educational subject specific pathfinders "that contain a list of library materials, web sites, and other information about a topic." The Science section includes topics focused on how the human body works, including the circulatory, digestive, excretory, muscular, nervous, respiratory, and skeletal systems. Each topic includes a detailed diagram and facts about the body system, and a variety of helpful books and online resources appropriate for children. This site is a useful resource for gathering information on a specific subject or browsing a variety of topics.

20

Abrolhos Bank Reef Health Evaluated by Means of Water Quality, Microbial Diversity, Benthic Cover, and Fish Biomass Data  

PubMed Central

The health of the coral reefs of the Abrolhos Bank (southwestern Atlantic) was characterized with a holistic approach using measurements of four ecosystem components: (i) inorganic and organic nutrient concentrations, [1] fish biomass, [1] macroalgal and coral cover and (iv) microbial community composition and abundance. The possible benefits of protection from fishing were particularly evaluated by comparing sites with varying levels of protection. Two reefs within the well-enforced no-take area of the National Marine Park of Abrolhos (Parcel dos Abrolhos and California) were compared with two unprotected coastal reefs (Sebastião Gomes and Pedra de Leste) and one legally protected but poorly enforced coastal reef (the “paper park” of Timbebas Reef). The fish biomass was lower and the fleshy macroalgal cover was higher in the unprotected reefs compared with the protected areas. The unprotected and protected reefs had similar seawater chemistry. Lower vibrio CFU counts were observed in the fully protected area of California Reef. Metagenome analysis showed that the unprotected reefs had a higher abundance of archaeal and viral sequences and more bacterial pathogens, while the protected reefs had a higher abundance of genes related to photosynthesis. Similar to other reef systems in the world, there was evidence that reductions in the biomass of herbivorous fishes and the consequent increase in macroalgal cover in the Abrolhos Bank may be affecting microbial diversity and abundance. Through the integration of different types of ecological data, the present study showed that protection from fishing may lead to greater reef health. The data presented herein suggest that protected coral reefs have higher microbial diversity, with the most degraded reef (Sebastião Gomes) showing a marked reduction in microbial species richness. It is concluded that ecological conditions in unprotected reefs may promote the growth and rapid evolution of opportunistic microbial pathogens. PMID:22679480

Bruce, Thiago; Meirelles, Pedro M.; Garcia, Gizele; Paranhos, Rodolfo; Rezende, Carlos E.; de Moura, Rodrigo L.; Filho, Ronaldo-Francini; Coni, Ericka O. C.; Vasconcelos, Ana Tereza; Amado Filho, Gilberto; Hatay, Mark; Schmieder, Robert; Edwards, Robert; Dinsdale, Elizabeth; Thompson, Fabiano L.

2012-01-01

21

Assessment of the Water Quality and Ecosystem Health of the Great Barrier Reef (Australia): Conceptual Models  

NASA Astrophysics Data System (ADS)

Run-off containing increased concentrations of sediment, nutrients, and pesticides from land-based anthropogenic activities is a significant influence on water quality and the ecologic conditions of nearshore areas of the Great Barrier Reef World Heritage Area, Australia. The potential and actual impacts of increased pollutant concentrations range from bioaccumulation of contaminants and decreased photosynthetic capacity to major shifts in community structure and health of mangrove, coral reef, and seagrass ecosystems. A detailed conceptual model underpins and illustrates the links between the main anthropogenic pressures or threats (dry-land cattle grazing and intensive sugar cane cropping) and the production of key contaminants or stressors of Great Barrier Reef water quality. The conceptual model also includes longer-term threats to Great Barrier Reef water quality and ecosystem health, such as global climate change, that will potentially confound direct model interrelationships. The model recognises that system-specific attributes, such as monsoonal wind direction, rainfall intensity, and flood plume residence times, will act as system filters to modify the effects of any water-quality system stressor. The model also summarises key ecosystem responses in ecosystem health that can be monitored through indicators at catchment, riverine, and marine scales. Selected indicators include riverine and marine water quality, inshore coral reef and seagrass status, and biota pollutant burdens. These indicators have been adopted as components of a long-term monitoring program to enable assessment of the effectiveness of change in catchment-management practices in improving Great Barrier Reef (and adjacent catchment) water quality under the Queensland and Australian Governments’ Reef Water Quality Protection Plan.

Haynes, David; Brodie, Jon; Waterhouse, Jane; Bainbridge, Zoe; Bass, Deb; Hart, Barry

2007-12-01

22

Coral Reefs Coral Reefs  

E-print Network

1 Coral Reefs Coral Reefs Coral Reef Formation Scleractinian Coral Polyps · Scleractinia = stony Growth Reef Building Corals · Reef building corals are colonial ­ create large 'coral heads' that may productivity. ­ So no phytoplankton ­ So no zooplankton ­ So no food for corals Reef Building Corals

Cochran-Stafira, D. Liane

23

Clues to Coral Reef Health: Integrating Radiative Transfer Modeling and Hyperspectral Data  

NASA Technical Reports Server (NTRS)

An important contribution to coral reef research is to improve spectral distinction between various health states of coral species in areas subject to harmful anthropogenic activity and climate change. New insights into radiative transfer properties of corals under healthy and stressed conditions can advance understandings of ecological processes on reefs and allow better assessments of the impacts of large-scale bleaching and disease events, Our objective was to examine the spectral and spatial properties of hyperspectral sensors that may be used to remotely sense changes in reef community health. We compare in situ reef environment spectra (healthy coral, stressed coral, dead coral, algae, and sand) with airborne hyperspectral data to identify important spectral characteristics and indices. Additionally, spectral measurements over a range of water depths, relief, and bottom types are compared to help quantify bottom-water column influences. In situ spectra were collected in July and August 2002 at the Long Rock site in the Andros Island, Bahamas coastal zone coral reef. Our primary emphasis was on Acropora palmata (or elkhorn coral), a major reef building coral, which is prevalent in the study area, but is suffering from white band disease. A. palmata is currently being, proposed as an endangered species because its populations have severely declined in many areas of the Caribbean. In addition to the A. palmata biotope, we have collected spectra of at least seven other coral biotopes that exist within the study area, each with different coral community composition, density of corals, relief, and size of corals. Coral spectral reflectance was then input into a radiative transfer model, CORALMOD (CM1), which is based on a leaf radiative transfer model. In CM1, input coral reflectance measurements produce modeled reflectance through an inversion at each visible wavelength to provide the absorption spectrum. Initially, we imposed a scattering baseline that is the same regardless of the coral condition and that coral is optically thick and no light is transmitted through coral. Here we will focus on methodology, experimental design, and initial findings of the in situ spectral measurements and preliminary output from the radiative transfer model.

Guild, Liane; Ganapol, Barry; Kramer, Philip; Armstrong, Roy; Gleason, Art; Torres, Juan; Johnson, Lee; Garfield, Toby; Peterson, David L. (Technical Monitor)

2002-01-01

24

The Mars Pathfinder Mission  

Microsoft Academic Search

Mars Pathfinder, one of the first Discovery-class missions (quick, low-cost projects with focused science objectives), will land a single spacecraft with a microrover and several instruments on the sttrface of Mars in 1997. Pathfinder will be the first mission to use a rover, carrying a chemical analysis instrument, to characterize the rocks and soils in a landing area over hundreds

Matthew P. Golombek

1997-01-01

25

Pathfinder Rear Ramp  

NASA Technical Reports Server (NTRS)

Mars Pathfinder's rear rover ramp can be seen successfully unfurled in this image, taken at the end of Sol 2 by the Imager for Mars Pathfinder (IMP). This ramp was later used for the deployment of the microrover Sojourner, which occurred at the end of Sol 2. Areas of a lander petal and deflated airbag are visible at left. The image helped Pathfinder scientists determine that the rear ramp was the one to use for rover deployment. At upper right is the rock dubbed 'Barnacle Bill,' which Sojourner will later study.

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.

1997-01-01

26

Jurassic Reef Park  

NSDL National Science Digital Library

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.

Reinhold Leinfelder

27

Pathfinder: Humans in space  

NASA Technical Reports Server (NTRS)

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

Anderson, John L.

1988-01-01

28

Pathfinder aircraft in flight  

NASA Technical Reports Server (NTRS)

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.'

1995-01-01

29

Reef grief  

NASA Astrophysics Data System (ADS)

As the first of the world's ecosystems faces extermination at our hands, coral reef ecologist Peter Sale -- Assistant Director of the Institute of Water, Environment and Health at the United Nations University in Ontario, Canada, and author of Our Dying Planet (published this autumn) -- talks to Nature Climate Change.

2011-10-01

30

Pathfinder Aircraft in Flight  

NASA Technical Reports Server (NTRS)

The Pathfinder research aircraft's wing structure was clearly defined as it soared under a clear blue sky during a test flight July 27, 1995, from Dryden Flight Research Center, Edwards, California. The center section and outer wing panels of the aircraft had ribs constructed of thin plastic foam, while the ribs in the inner wing panels are fabricated from lightweight composite material. Developed by AeroVironment, Inc., the Pathfinder was one of several unmanned aircraft being evaluated under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. 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.

1995-01-01

31

Health of the coral reefs at the US Navy Base, Guantánamo Bay, Cuba: a preliminary report based on isotopic records from gorgonians.  

PubMed

Specimens of the gorgonian Plexaura homomalla were sampled from several areas along the fringing reefs fronting the United States Naval Base at Guantánamo Bay, Cuba. Sample coverage extended from apparently healthy reefs in oceanic waters to declining reefs located in the plume of the drainage from upper parts of Guantánamo Bay. Tentacle tips were excised, and trunk sections were cut and polished. Stable isotope ratios of nitrogen (?(15)N) and carbon indicate a strong correlation of reef health with proximity to the plume of the river. Of all the worldwide cases in which land-based sources of pollution have impacted reefs, this one may well be the most intractable. The US Navy has jurisdiction over the reefs, with the obligation to protect them, yet the threat comes down the river from Cuba. PMID:24735775

Risk, Michael J; Burchell, Meghan; Brunton, Dalston A; McCord, Michael R

2014-06-15

32

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)

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.

Rolfe, John; Windle, Jill

2011-12-01

33

Coral Reefs Under Stress  

NSDL National Science Digital Library

Coral reefs are more critical to an oceanâÂÂs 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.

Peter Mumby (University of Exeter;)

2009-10-05

34

The LISA Pathfinder mission  

NASA Astrophysics Data System (ADS)

LISA Pathfinder, the second of the European Space Agency's Small Missions for Advanced Research in Technology (SMART), is a dedicated technology demonstrator for future spaceborne gravitational wave observatories, for example the proposed ESA mission, NGO. The technologies required for NGO are many and extremely challenging. This coupled with the fact that some flight hardware cannot be fully tested on ground due to Earth-induced noise, led to the implementation of the LISA Pathfinder mission to test the critical NGO technologies in a flight environment. LISA Pathfinder essentially mimics one arm of the NGO constellation by shrinking the 1 million kilometre armlength down to a few tens of centimetres, giving up the sensitivity to gravitational waves, but keeping the measurement technology: the distance between the two test masses is measured using a laser interferometric technique similar to one aspect of the NGO interferometry system. The scientific objective of the LISA Pathfinder mission consists then of the first in-flight test of low frequency gravitational wave detection metrology. Here I will present an overview of the mission, focusing on scientific and technical goals, followed by the current status of the project.

McNamara, Paul

2012-07-01

35

Mapping and monitoring the health and vitality of coral reefs from satellite: a biospheric approach.  

PubMed

Biospheric studies of coral reefs require a planetary perspective that only remote sensing from space can provide. This article reviews aspects of monitoring and mapping coral reefs using Landsat and Spot satellite images. It details design considerations for developing a sensor for equatorial orbiting spacecraft, including spectral characteristics of living corals and the spatial resolution required to map coral reef communities. Possible instrumentation choices include computer techniques, filtered imagers, push-broom spectral imagery, and a newly developed hyperspectral imaging scheme using tomographic reconstruction. We compare the salient features of each technique and describe concepts for a payload to conduct planetary-scale coral reef monitoring. PMID:11543553

Dustan, P; Chakrabarti, S; Alling, A

2000-01-01

36

Development of ecotoxicology procedures for use in assessing health of coral reefs  

SciTech Connect

There is widespread concern over the apparent worldwide decline in the health of coral reefs. However, assessment methods, other than long-term monitoring, have not yet been attempted. To remedy this the authors are developing ecotoxicology procedures to assess the effects of water quality factors on the corals themselves. Because of the problems of working with large, attached organisms, the authors have concentrated on developing small clonal preparations from corals with both a branching and a massive growth-form. For branching corals, tips (`nubbins`) are removed, and the cut surface ground smooth before cementing to 30mm x 30mm acrylic squares. Cores, or `explants`, 25mm in diameter are removed from massive corals and cemented into injection-moulded plastic cups, to protect the cut surfaces of the skeleton. Trays of up to 18 nubbins and explants may then be transferred to the reef, where they are affixed to previously installed concrete breeze blocks. They may then be retrieved as required to assess the effects of water quality upon them. For laboratory ecotoxicology experiments, the authors have devised a system of artificial lighting, using halide lamps, to grow coral nubbins and explants under controlled conditions. To test the effects of pollutants, the authors use measurements of respiration, photosynthesis and skeletal growth rate. Growth is measured by a very simple buoyant weighing procedure, which requires only an analytical laboratory balance, and an easily-constructed plastic box-shaped chamber. The method is sufficiently sensitive to measure growth over a 24 hour period in some fast-growing corals. The authors will describe the results of initial experiments, carried out at the Bellairs Research Institute, Barbados, on the effects of different levels of phosphate and nitrate in the seawater. For the first time, they are able to demonstrate the concentration-related decrease in growth rate associated with nitrate eutrophication.

Davies, P.S.; Marubini, F. [Univ. of Glasgow (United Kingdom). Division of Environmental and Evolutionary Biology

1995-12-31

37

The LISA Pathfinder Mission  

NASA Astrophysics Data System (ADS)

Laser Interferometer Space Antenna (LISA) Pathfinder (formerly known as SMART-2) is a European Space Agency mission designed to pave the way for the joint ESA/NASA 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 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 (LPF) essentially mimics one arm of space-borne gravitational wave detectors by shrinking the million kilometer scale armlengths down to a few tens of centimeters, giving up the sensitivity to gravitational waves, but keeping the measurement technology. The scientific objective of the LPF mission consists then of the first in-flight test of low frequency gravitational wave detection metrology.

McNamara, Paul W.

2013-01-01

38

The LISA Pathfinder Mission  

NASA Technical Reports Server (NTRS)

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.

Stebbins, Robin

2009-01-01

39

Pathfinder Air Bags  

NASA Technical Reports Server (NTRS)

Engineers test huge, multi-lobed air bags, which will envelope and protect the Mars Pathfinder spacecraft before it impacts the surface of Mars. The air bags, manufactured by ILC Dover of Frederica, Delaware, are composed of four large bags with six smaller, interconnected spheres within each bag. The bags measure 5 meters (17 feet) tall and about 5 meters (17 feet) in diameter. As Pathfinder is descending to the Martian surface on a parachute, an onboard altimeter inside the lander will monitor its distance from the ground. The computer will inflate these large air bags about 100 meters (330 feet) above the surface of Mars. ILC Dover is the same company that manufactures spacesuits.

1995-01-01

40

VR for Mars Pathfinder  

NASA Technical Reports Server (NTRS)

Virtual reality (VR) technology has played an integral role for Mars Pathfinder mission, operations Using an automated machine vision algorithm, the 3d topography of the Martian surface was rapidly recovered fro -a the stereo images captured. by the Tender camera to produce photo-realistic 3d models, An advanced, interface was developed for visualization and interaction with. the virtual environment of the Pathfinder landing site for mission scientists at the Space Flight Operations Facility of the Jet Propulsion Laboratory. The VR aspect of the display allowed mission scientists to navigate on Mars in Bud while remaining here on Earth, thus improving their spatial awareness of the rock field that surrounds the lenders Measurements of positions, distances and angles could be easily extracted from the topographic models, providing valuable information for science analysis and mission. planning. Moreover, the VR map of Mars has also been used to assist with the archiving and planning of activities for the Sojourner rover.

Blackmon, Theodore

1998-01-01

41

The LISA Pathfinder Mission  

NASA Astrophysics Data System (ADS)

LISA Pathfinder (formerly known as SMART-2) is an European Space Agency 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 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 (LPF) essentially mimics one arm of spaceborne gravitational wave detectors by shrinking the million kilometre scale armlengths down to a few tens of centimetres, giving up the sensitivity to gravitational waves, but keeping the measurement technology. The scientific objective of the LISA Pathfinder mission consists then of the first in-flight test of low frequency gravitational wave detection metrology. In this paper I will give a brief overview of the mission, focusing on scientific and technical goals.

McNamara, P.; 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.; Dixton, G.; Dolesi, R.; Dumbar, 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.; Mendes, J.; Mitchell, E.; Nicolodi, D.; Nofrarias, M.; 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

42

Mars Pathfinder Status at Launch  

NASA Technical Reports Server (NTRS)

The Mars Pathfinder Flight System is in final test, assembly and launch preparations at the Kennedy Space Center in Florida. Launch is scheduled for 2 Dec. 1996. The Flight System development, in particular the Entry, Descent, and Landing (EDL) system, was a major team effort involving JPL, other NASA centers and industry. This paper provides a summary Mars Pathfinder description and status at launch. In addition, a section by NASA's Langley Research Center, a key EDL contributor, is provided on their support to Mars Pathfinder. This section is included as an example of the work performed by Pathfinder team members outside JPL.

Spear, A. J.; Freeman, Delma C., Jr.; Braun, Robert D.

1996-01-01

43

Spatial trends in community and health-related characteristics of Galveston Bay oyster reefs  

E-print Network

The spatial trends in the oyster community and healthrelated variables for Galveston Bay oyster reefs indicated that some other factors in addition to salinity are major structuring forces. Three different directional trends were found including one...

Song, Junggeun

1994-01-01

44

Delta II Mars Pathfinder  

NASA Technical Reports Server (NTRS)

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.

1998-01-01

45

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.

1997-01-01

46

Pathfinder Rover Atop Mermaid Dune  

NASA Technical Reports Server (NTRS)

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).

1997-01-01

47

LISA Pathfinder: mission and status  

NASA Astrophysics Data System (ADS)

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 noise led to the implementation of the LISA Pathfinder mission to test the critical LISA technologies in a flight environment. LISA Pathfinder essentially mimics one arm of the LISA constellation by shrinking the 5 million kilometre armlength down to a few tens of centimetres, giving up the sensitivity to gravitational waves, but keeping the measurement technology: the distance between the two test masses is measured using a laser interferometric technique similar to one aspect of the LISA interferometry system. The scientific objective of the LISA Pathfinder mission consists then of the first in-flight test of low frequency gravitational wave detection metrology. LISA Pathfinder is due to be launched in 2013 on-board a dedicated small launch vehicle (VEGA). After a series of apogee raising manoeuvres using an expendable propulsion module, LISA Pathfinder will enter a transfer orbit towards the first Sun-Earth Lagrange point (L1). After separation from the propulsion module, the LPF spacecraft will be stabilized using the micro-Newton thrusters, entering a 500 000 km by 800 000 km Lissajous orbit around L1. Science results will be available approximately 2 months after launch.

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

2011-05-01

48

The Australian SKA Pathfinder  

NASA Astrophysics Data System (ADS)

The Australian Square Kilometre Array Pathfinder (ASKAP) will be the fastest cm-wave survey radio-telescope and is under construction on the new Murchison Radio-astronomy Observatory (MRO) in Western Australia. ASKAP consists of 36 12-meter 3-axis antennas, each with a large chequerboard phased array feed (PAF) operating from 0.7 to 1.8 GHz, and digital beamformer preceding the correlator. The PAF has 94 dual-polarization elements (188 receivers) and the beamformer will provide about 36 beams (at 1.4 GHz) to produce a 30 square degree field of view, allowing rapid, deep surveys of the entire visible sky. As well as a large field of view ASKAP has high spectral resolution across the 304 MHz of bandwidth processed at any one time generating a large data-rate (30Gb/sec in to the imaging system) that requires real-time processing of the data. To minimise this processing and maximise the field of view for long observations the antenna incorporates a third axis, which keeps the PAF field of view and sidelobes fixed relative to the sky. This largely eliminates time varying artefact in the data that is processed. The MRO is 315 kilometres north-east of Geraldton, in Western Australia’s Mid West region. The primary infrastructure construction for ASKAP and other telescopes hosted at the Murchison Radio-astronomy Observatory has now been completed by CSIRO, the MRO manager, including installation of the fibre connection from the MRO site to Perth via Geraldton. The radio-quietness of the region is protected by the Mid West Radio Quiet Zone, implemented by the Australian Federal Government, out to a radius of 260km surrounding the MRO.

Schinckel, Antony E.; Bunton, John D.; Cornwell, Tim J.; Feain, Ilana; Hay, Stuart G.

2012-09-01

49

New Caledonia surface lagoon chlorophyll modeling as coastal reef area health indicator  

NASA Astrophysics Data System (ADS)

The major part of the New Caledonia (NC) lagoon was classified as UNESCO Natural Site of Humanity Patrimony. Indeed, 22 175 km2 of tropical coral lagoon area exhibit high biodiversity. The NC lagoon is semi enclosed and connected to the Coral Sea through a barrier reef segmented by narrow passes. The environment is oligotrophic, due to important flush during trade winds events, and bathymetry is highly variable. In order to predict eutrophication events, we used an extension of a 3D coupled physical-biogeochemical model recently developed on NC south western lagoon. The model is based on the Nitrogen and Carbon cycles, relating the variable stoechiometry of the elements in each biological compartment. The ecological model was developed to include an explicit description of the microbial loop. The resulting coupled model, forced by tide, wind, light, temperature and freshwater inputs, was used to calculate phytoplankton biomass, bacterial production, dissolved organic matter concentrations and nutrient recycling. Here we present results issued from the 3D coupled model ECO3M_LAGOON (biogeochemical, LOPB-IRD) and MARS3D (regional physical model, IFREMER-IRD) describing spatial and temporal interactions between water motion and biology, on larger domain including reef barrier and water exchanges through ocean-lagoon interface. To validate physical processes in the lagoon we used in situ data collected during field cruise (ValHyBio 2008, La Niña episode). Surface chlorophyll concentrations are compared with water color data from ValHyBio cruise and satellite data (MODIS/MERIS) corrected from bathymetry effects.

Fuchs, R.; Pinazo, C.; Douillet, P.; Dupouy, C.; Faure, V.; Mangin, A.

2010-10-01

50

Spacetime Metrology with LISA Pathfinder  

NASA Astrophysics Data System (ADS)

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.

Congedo, Giuseppe

2012-04-01

51

Spacetime Metrology with LISA Pathfinder  

E-print Network

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 3\\times10^{-14} m s^{-2} Hz^{-1/2} and track their relative motion to within the required differential displacement measurement noise of 9\\times10^{-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.

Giuseppe Congedo

2012-04-19

52

Serge Andre foue t Hector M. Guzman Coral reef distribution, status and geomorphologybiodiversity  

E-print Network

REPORT Serge Andre´ foue¨ t � Hector M. Guzman Coral reef distribution, status and geomorphology of the reef geomor- phology and benthic communities of Kuna Yala coral reefs (Caribbean Panama) comes from of coral, octocorals, and sponges) and reef health (coral versus algal cover). For a total reef system

Bermingham, Eldredge

53

Great Barrier Reef  

article title:  Australia's Great Barrier Reef     View Larger Image ... not a single reef, but a vast maze of reefs, passages, and coral cays (islands that are part of the reef). This nadir true-color image was ...

2013-04-16

54

Which Environmental Factors Predict Seasonal Variation in the Coral Health of Acropora digitifera and Acropora spicifera at Ningaloo Reef?  

PubMed Central

The impact of physico-chemical factors on percent coral cover and coral health was examined on a spatial basis for two dominant Acropora species, A. digitifera and A. spicifera, at Ningaloo Reef (north-western Australia) in the southeast Indian Ocean. Coral health was investigated by measuring metabolic indices (RNA/DNA ratio and protein concentration), energy levels (lipid ratio) and autotrophic indices (chlorophyll a (chl a) and zooxanthellae density) at six stations during typical seasons (austral autumn 2010 (March and April), austral winter 2010 (August)) and during an extreme La Niña event in summer 2011 (February). These indices were correlated with 15 physico-chemical factors (measured immediately following coral sampling) to identify predictors for health indices. Variations in metabolic indices (protein concentration and RNA/DNA ratio) for A. spicifera were mainly explained by nitrogen, temperature and zooplankton concentrations under typical conditions, while for A. digitifera, light as well as phytoplankton, in particular picoeukaryotes, were important, possibly due to higher energy requirement for lipid synthesis and storage in A. digitifera. Optimum metabolic values occurred for both Acropora species at 26–28°C when autotrophic indices (chl a and zooxanthellae density) were lowest. The extreme temperature during the La Niña event resulted in a shift of feeding modes, with an increased importance of water column plankton concentrations for metabolic rates of A. digitifera and light and plankton for A. spicifera. Our results suggest that impacts of high sea surface temperatures during extreme events such as La Niña may be mitigated via reduction on metabolic rates in coral host. The high water column plankton concentrations and associated low light levels resulted in a shift towards high symbiont densities, with lower metabolic rates and energy levels than the seasonal norm for the coral host. PMID:23637770

Hinrichs, Saskia; Patten, Nicole L.; Feng, Ming; Strickland, Daniel; Waite, Anya M.

2013-01-01

55

Coral Reefs  

NSDL National Science Digital Library

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.

Productions, Jonathan B.

2012-03-01

56

Software Aids Visualization Of Mars Pathfinder Mission  

NASA Technical Reports Server (NTRS)

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.

Weidner, Richard J.

1996-01-01

57

Using MODIS data for understanding changes in seagrass meadow health: a case study in the Great Barrier Reef (Australia).  

PubMed

Stretching more than 2000 km along the Queensland coast, the Great Barrier Reef Marine Park (GBR) shelters over 43,000 square km of seagrass meadows. Despite the status of marine protected area and World Heritage listing of the GBR, local seagrass meadows are under stress from reduced water quality levels; with reduction in the amount of light available for seagrass photosynthesis defined as the primary cause of seagrass loss throughout the GBR. Methods have been developed to map GBR plume water types by using MODIS quasi-true colour (hereafter true colour) images reclassified in function of their dominant colour. These data can be used as an interpretative tool for understanding changes in seagrass meadow health (as defined in this study by the seagrass area and abundance) at different spatial and temporal scales. We tested this method in Cleveland Bay, in the northern GBR, where substantial loss in seagrass area and biomass was detected by annual monitoring from 2007 to 2011. A strong correlation was found between bay-wide seagrass meadow area and biomass and exposure to turbid Primary (sediment-dominated) water type. There was also a strong correlation between the changes of biomass and area of individual meadows and exposure of seagrass ecosystems to Primary water type over the 5-year period. Seagrass meadows were also grouped according to the dominant species within each meadow, irrespective of location within Cleveland Bay. These consolidated community types did not correlate well with the exposure to Primary water type, and this is likely to be due to local environmental conditions with the individual meadows that comprise these groupings. This study proved that remote sensing data provide the synoptic window and repetitivity required to investigate changes in water quality conditions over time. Remote sensing data provide an opportunity to investigate the risk of marine-coastal ecosystems to light limitation due to increased water turbidity when in situ water quality data is not available or is insufficient. PMID:24709476

Petus, Caroline; Collier, Catherine; Devlin, Michelle; Rasheed, Michael; McKenna, Skye

2014-07-01

58

Community structure and coral status across reef fishing intensity gradients in Palk Bay reef, southeast coast of India.  

PubMed

Coral reef fishes are exploited without the knowledge of their sustainability and their possible effect in altering the community structure of a coral reef ecosystem. Alteration of the community structure could cause a decline in the health of coral reefs and its services. We documented the coral community structure, status of live corals and reef fish assemblages in Palk Bay at the reef fishing hotspots and its nearby reef area with minimum fishing pressure and compared it with a control reef area where reef fishing was banned for more than two decades. The comparison was based on the percent cover of different forms of live corals, their diversity and the density and diversity of reef fishes. The reef fish stock in the reef fishing hotspots and its neighbouring reef was lower by 61 and 38%, respectively compared to the control reef. The herbivore fish Scarus ghobban and Siganus javus were exploited at a rate of 250 and 105 kg month(-1) fishermen(-1), respectively, relatively high comparing the small reef area. Live and dead corals colonized by turf algae were predominant in both the reef fishing hotspots and its nearby coral ecosystems. The percent cover of healthy live corals and live corals colonized by turf algae was <10 and >80%, respectively, in the intensively fished coral ecosystems. The corals were less diverse and the massive Porites and Favia colonies were abundant in the intensive reef fishing sites. Results of this study suggest that the impact of reef fish exploitation was not solely restricted to the intensively fished reefs, but also to the nearby reefs which play a critical role in the resilience of degraded reef ecosystems. PMID:24859909

Manikandan, B; Ravindran, J; Shrinivaasu, S; Marimuthu, N; Paramasivam, K

2014-10-01

59

Mars Pathfinder mission operations concepts  

NASA Technical Reports Server (NTRS)

The Mars Pathfinder Project plans a December 1996 launch of a single spacecraft. After jettisoning a cruise stage, an entry body containing a lander and microrover will directly enter the Mars atmosphere and parachute to a hard landing near the sub-solar latitude of 15 degrees North in July 1997. Primary surface operations last for 30 days. Cost estimates for Pathfinder ground systems development and operations are not only lower in absolute dollars, but also are a lower percentage of total project costs than in past planetary missions. Operations teams will be smaller and fewer than typical flight projects. Operations scenarios have been developed early in the project and are being used to guide operations implementation and flight system design. Recovery of key engineering data from entry, descent, and landing is a top mission priority. These data will be recorded for playback after landing. Real-time tracking of a modified carrier signal through this phase can provide important insight into the spacecraft performance during entry, descent, and landing in the event recorded data is never recovered. Surface scenarios are dominated by microrover activity and lander imaging during 7 hours of the Mars day from 0700 to 1400 local solar time. Efficient uplink and downlink processes have been designed to command the lander and microrover each Mars day.

Sturms, Francis M., Jr.; Dias, William C.; Nakata, Albert Y.; Tai, Wallace S.

1994-01-01

60

Coral reef restoration  

Microsoft Academic Search

Coral reefs are widely recognized for concentration of biological activity, fisheries and tourism, coastal protection, geological processes, and aesthetic wonder. A principal cause of reef damage in Florida is ships running into reefs. The other major human impact on Florida’s reefs is dredging for beach renourishment and channel maintenance. In response to chronic reef damage, federal and state agencies and

Walter C Jaap

2000-01-01

61

Navigation Flight Operations for Mars Pathfinder  

NASA Technical Reports Server (NTRS)

On July 4, 1997, Mars Pathfinder became the first spacecraft to land on the surface of Mars in 21 years. Pathfinder was launched on December 4, 1996 and spent seven months en route to the red planet. This report discusses the navigation flight experience for the Mars Pathfinder interplanetary cruise. In particular, orbit determination and maneuver design and execution results are presented. Special emphasis is given to the navigation role in the days and hours leading up to and including the Entry, Descent, and Landing (EDL) phase.

Vaughan, Robin M.; Kallemeyn, Pieter H., Jr.; Spencer, David A.; Braun, Robert D.

2004-01-01

62

Mars pathfinder lander deployment mechanisms  

NASA Technical Reports Server (NTRS)

The Mars Pathfinder Lander employs numerous mechanisms, as well as autonomous mechanical functions, during its Entry, Descent and Landing (EDL) Sequence. This is the first US lander of its kind, since it is unguided and airbag-protected for hard landing using airbags, instead of retro rockets, to soft land. The arrival condition, location, and orientation of the Lander will only be known by the computer on the Lander. The Lander will then autonomously perform the appropriate sequence to retract the airbags, right itself, and open, such that the Lander is nearly level with no airbag material covering the solar cells. This function uses two different types of mechanisms - the Airbag Retraction Actuators and the Lander Petal Actuators - which are designed for the high torque, low temperature, dirty environment and for limited life application. The development of these actuators involved investigating low temperature lubrication, Electrical Discharge Machining (EDM) to cut gears, and gear design for limited life use.

Gillis-Smith, Greg R.

1996-01-01

63

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

Microsoft Academic Search

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\\u000a and hard-coral assemblages as indicators of changes in water quality was assessed on 27 inshore reefs along the Great Barrier\\u000a Reef. Environmental variables (i.e., several water quality

S. Uthicke; A. Thompson; B. Schaffelke

2010-01-01

64

Mars Pathfinder Two-Dimensional Model  

NSDL National Science Digital Library

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.

2012-08-03

65

Orientation of Windtails at Pathfinder Landing Site  

NASA Technical Reports Server (NTRS)

This is a representation of sediment tails noted at the Mars Pathfinder landing site. The arrows in the figure represent the inferred downwind direction, based on our understanding of the deposition of very fine sediment around surface rocks. The inferred wind direction therefore, is from the northeast blowing toward the southwest. This wind trend matched that of light and dark 'streaks' of sediment in and around Martian craters in the region that have were seen by the Viking spacecraft. The detailed map was prepared by Mars Pathfinder scientists from Arizona State University on a base image created by MPF scientists from the NASA Ames research facility.

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).

1997-01-01

66

Power and pyro subsystems for Mars Pathfinder  

SciTech Connect

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.

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

1997-12-31

67

Pathfinder-Plus flight in Hawaii  

NASA Technical Reports Server (NTRS)

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.

2002-01-01

68

The Mars Pathfinder ASI\\/MET Investigation  

Microsoft Academic Search

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

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

69

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

NASA Astrophysics Data System (ADS)

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.

Phipps, A.

2012-04-01

70

Mapping Oyster Reef Habitats in Mobile Bay  

NASA Technical Reports Server (NTRS)

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.

Bolte, Danielle

2011-01-01

71

LISA Pathfinder Instrument Data Analysis  

NASA Technical Reports Server (NTRS)

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 subtraction 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 preflight hardware ground tests and possible noise subtraction strategies for in-flight instrument operations.

Guzman, Felipe

2010-01-01

72

TOVS Pathfinder product validation and intercomparison  

NASA Technical Reports Server (NTRS)

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.

1992-01-01

73

Mars Pathfinder Atmospheric Entry Navigation Operations  

NASA Technical Reports Server (NTRS)

On July 4, 1997, after traveling close to 500 million km, the Pathfinder spacecraft successfully completed entry, descent, and landing, coming to rest on the surface of Mars just 27 km from its target point. In the present paper, the atmospheric entry and approach navigation activities required in support of this mission are discussed. In particular, the flight software parameter update and landing site prediction analyses performed by the Pathfinder operations navigation team are described. A suite of simulation tools developed during Pathfinder's design cycle, but extendible to Pathfinder operations, are also presented. Data regarding the accuracy of the primary parachute deployment algorithm is extracted from the Pathfinder flight data, demonstrating that this algorithm performed as predicted. The increased probability of mission success through the software parameter update process is discussed. This paper also demonstrates the importance of modeling atmospheric flight uncertainties in the estimation of an accurate landing site. With these atmospheric effects included, the final landed ellipse prediction differs from the post-flight determined landing site by less then 0.5 km in downtrack.

Braun, R. D.; Spencer, D. A.; Kallemeyn, P. H.; Vaughan, R. M.

1997-01-01

74

Overhead view of Pathfinder Landing Site  

NASA Technical Reports Server (NTRS)

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).

1997-01-01

75

Dynamic Pathfinders: Leveraging Your OPAC to Create Resource Guides  

ERIC Educational Resources Information Center

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…

Hunter, Ben

2008-01-01

76

Mars Pathfinder Mission Telescopic Observational Support  

NASA Astrophysics Data System (ADS)

Monitoring of the martian atmosphere by professional and amateur astronomers during the 1997 opposition is important for the Mars Pathfinder project because the entry, descent, and landing (EDL) sequence can be fine-tuned based on updated knowledge of the opacity and density structure of the atmosphere. The atmospheric models that have been used to develop Pathfinder EDL and surface scenarios are based on Viking Lander data, but it has been recognized that the martian atmosphere has recently been significantly colder and clearer than during the Viking missions. On the martian surface, lander and rover power depend on the insolation at the surface and radiative transfer in the atmosphere. Power is needed both to keep electronics warm during the cold martian night and for telecommunications. Hence, the amount of data that can be returned to Earth, and therefore operational scenarios, will depend on the temperature and amount of dust in the martian atmosphere. In addition, observations of Mars during Pathfinder surface operations with the landing site near the sub-Earth point would allow Pathfinder observations to be placed in a global context. Conversely, Pathfinder data will be useful in calibrating telescopic observations of Martian atmospheric opacity and temperatures. Observing time has been allocated for microwave observations of Mars from Kitt Peak and WF/PC2 imaging from the Hubble Space Telescope during the Pathfinder mission. Planning is also underway among amateur astronomers worldwide: for more information, see the MarsWatch home pages at the following URLs: http://mpfwww.jpl.nasa.gov/mpf/marswatch.html http://astrosun.tn.cornell.edu/marsnet/mnhome.html

Herkenhoff, K. E.; Golombek, M. P.; Anderson, R. C.; Bell, J. F., III

1996-09-01

77

Author's personal copy Coral Reefs  

E-print Network

Author's personal copy Coral Reefs D E Burkepile and M E Hay, Georgia Institute of Technology Ecological Interactions on Coral Reefs Replenishment of Coral Reefs: The Role of Reproduction and Recruitment in the Ecology of Reefs Landscape Ecology of Coral Reefs: Connections of Coral Reefs to Mangrove and Seagrass

Burkepile, Deron

78

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

PubMed Central

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

Forsman, Rick B.

2005-01-01

79

MARS PATHFINDER PETAL CLOSURE IN SAEF-2  

NASA Technical Reports Server (NTRS)

In the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2), the petals on the Mars Pathfinder lander are being closed for flight and won't open again until the lander has touched down on the Martian surface in July 1997. Tucked inside the compact lander are the Surveyor small rover, which will become the first vehicle to traverse the Martian surface, and the lander's Mars Pathfinder Imager, a stereo-imaging system camera that will capture images of both the surrounding terrain as well as the rover's excursions, and other instrumentation and equipment. The outside of the tetrahedral- shaped lander is padded with airbags that will help cushion the lander from the impact of landing. Once assembly of the entry vehicle is complete, it will be mated to the cruise stage that will carry Pathfinder on its direct trajectory to Mars, and then to an upper stage booster. The Mars Pathfinder is slated for launch aboard a Delta II expendable launch vehicle on Dec. 2 at the beginning of a 24-day launch period.

1996-01-01

80

Mechanical design of the Mars Pathfinder mission  

NASA Technical Reports Server (NTRS)

The Mars Pathfinder mission and the Sojourner rover is reported on, with emphasis on the various mission steps and the performance of the technologies involved. The mechanical design of mission hardware was critical to the success of the entry sequence and the landing operations. The various mechanisms employed are considered.

Eisen, Howard Jay; Buck, Carl W.; Gillis-Smith, Greg R.; Umland, Jeffrey W.

1997-01-01

81

Regenerative fuel cell systems for project pathfinder  

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

82

In-flight Diagnostics in LISA Pathfinder  

Microsoft Academic Search

LISA PathFinder (LPF) will be flown with the objective to test in space key technologies for LISA. However its sensitivity goals are, for good reason, one order of magnitude less than those which LISA will have to meet, both in drag-free and optical metrology requirements, and in the observation frequency band. While the expected success of LPF will of course

Alberto Lobo; Miquel Nofrarias; Juan Ramos-Castro; Josep Sanjuan; Aleix Conchillo; J. A. Ortega; Xevi Xirgu; Henrique Araujo; Cesar Boatella; Mokhtar Chmeissani; Catia Grimani; Carles Puigdengoles; Peter Wass; E. García-Berro; S. García; L. M. Martínez; Gustau Montero

2006-01-01

83

Free-flight experiments in LISA Pathfinder  

E-print Network

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.

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

2014-12-29

84

Strategy for selecting Mars Pathfinder landing sites  

NASA Technical Reports Server (NTRS)

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.

Greeley, Ronald; Kuzmin, Ruslin O.

1994-01-01

85

Journey to the Reef  

NSDL National Science Digital Library

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-gra

Bryson, Linda

2010-01-01

86

Ventifacts at the Pathfinder landing site  

USGS Publications Warehouse

About half of the rocks at the Mars Pathfinder Ares Vallis landing site appear to be ventifacts, rocks abraded by windborne particles. Comparable resolution images taken by the Imager for Mars Pathfinder (IMP) camera and the Viking landers show that ventifacts are more abundant at the Pathfinder site. The ventifacts occur in several forms, including rocks with faceted edges, finger-like projections, elongated pits, flutes, grooves, and possible rills. The trends of elongated pits, flutes, grooves, and rills cluster at ???280-330?? clockwise from north and generally dip 10-30?? away from their trend direction. These orientations are indicative of southeast to northwest winds and differ from the trend of wind tails at the landing site, the direction of local wind streaks, and predictions of the Global Circulation Model, all of which indicate northeast to southwest winds. The disparity between these data sets strongly suggests that local circulation patterns have changed since the abrasion of the ventifacted rocks. The greater number of ventifacts at the Pathfinder site compared to either of the Viking sites is most easily explained as being due to a larger supply of abrading particles, composed of either sand-sized grains or indurated dust aggregates, and higher surface roughness, which should increase the momentum of saltating grains. The Pathfinder ventifacts may have formed shortly after the deposition of outflow channel sediments nearly 2 Gry ago, when a large local supply of abrading particles should have been abundant and atmospheric conditions may have been more conducive to rock abrasion from saltating grains. Based on how ventifacts form on Earth, the several ventifact forms seen at the Pathfinder site and their presence on some rocks but not on others are probably due to local airflow conditions, original rock shape, exposure duration, rock movement, and to a lesser extent, rock lithology. The abundance of ventifacts at the Pathfinder site, together with other evidence of weathering, indicates that unaltered rock surfaces are rare on Mars. Copyright 1999 by the American Geophysical Union.

Bridges, N.T.; Greeley, R.; Haldemann, A.F.C.; Herkenhoff, K.E.; Kraft, M.; Parker, T.J.; Ward, A.W.

1999-01-01

87

Great Barrier Reef  

NSDL National Science Digital Library

This lesson addresses the environmental importance of coral reefs and the threats to the conservation of reefs. Through the process of gathering geographic information about a place (in this case, the Great Barrier Reef), students will learn how a geographic focus can sharpen their insights about a conservation issue.

88

Mars Pathfinder Landing Site and Surroundings  

NASA Technical Reports Server (NTRS)

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

2007-01-01

89

Disk Galaxies in the Magneticum Pathfinder Simulations  

NASA Astrophysics Data System (ADS)

We present Magneticum Pathfinder, a new set of hydrodynamical cosmological simulations covering a large range of cosmological scales. Among the important physical processes included in the simulations are the chemical and thermodynamical evolution of the diffuse gas as well as the evolution of stars and black holes and the corresponding feedback channels. In the high resolution boxes aimed at studies of galaxy formation and evolution, populations of both disk and spheroidal galaxies are self-consistently reproduced. These galaxy populations match the observed stellar mass function and show the same trends for disks and spheroids in the mass-size relation as observations from the SDSS. Additionally, we demonstrate that the simulated galaxies successfully reproduce the observed specific angular-momentum-mass relations for the two different morphological types of galaxies. In summary, the Magneticum Pathfinder simulations are a valuable tool for studying the assembly of cosmic and galactic structures in the universe.

Remus, Rhea-Silvia; Dolag, Klaus; Bachmann, Lisa K.; Beck, Alexander M.; Burkert, Andreas; Hirschmann, Michaela; Teklu, Adelheid

2015-02-01

90

Potential landing sites for Mars Pathfinder  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

91

Mars Pathfinder Project: Planetary Constants and Models  

NASA Technical Reports Server (NTRS)

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.

Vaughan, Robin

1995-01-01

92

Pathfinder-Plus aircraft in flight  

NASA Technical Reports Server (NTRS)

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.

1998-01-01

93

Overhead View of Area Surrounding Pathfinder  

NASA Technical Reports Server (NTRS)

Overhead view of the area surrounding the Pathfinder lander illustrating the Sojourner traverse. Red rectangles are rover positions at the end of sols 1-30. Locations of soil mechanics experiments, wheel abrasion experiments, and APXS measurements are shown. The A numbers refer to APXS measurements as discussed in the paper by Rieder et al. (p. 1770, Science Magazine, see image note). Coordinates are given in the LL frame.

The photorealistic, interactive, three-dimensional virtual reality (VR) terrain models were created from IMP images using a software package developed for Pathfinder by C. Stoker et al. as a participating science project. By matching features in the left and right camera, an automated machine vision algorithm produced dense range maps of the nearfield, which were projected into a three-dimensional model as a connected polygonal mesh. Distance and angle measurements can be made on features viewed in the model using a mouse-driven three-dimensional cursor and a point-and-click interface. The VR model also incorporates graphical representations of the lander and rover and the sequence and spatial locations at which rover data were taken. As the rover moved, graphical models of the rover were added for each position that could be uniquely determined using stereo images of the rover taken by the IMP. Images taken by the rover were projected into the model as two-dimensional 'billboards' to show the proper perspective of these images.

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).

1997-01-01

94

Canadian Hydrogen Intensity Mapping Experiment (CHIME) pathfinder  

NASA Astrophysics Data System (ADS)

A pathfinder version of CHIME (the Canadian Hydrogen Intensity Mapping Experiment) is currently being commissioned at the Dominion Radio Astrophysical Observatory (DRAO) in Penticton, BC. The instrument is a hybrid cylindrical interferometer designed to measure the large scale neutral hydrogen power spectrum across the redshift range 0.8 to 2.5. The power spectrum will be used to measure the baryon acoustic oscillation (BAO) scale across this poorly probed redshift range where dark energy becomes a significant contributor to the evolution of the Universe. The instrument revives the cylinder design in radio astronomy with a wide field survey as a primary goal. Modern low-noise amplifiers and digital processing remove the necessity for the analog beam forming that characterized previous designs. The Pathfinder consists of two cylinders 37m long by 20m wide oriented north-south for a total collecting area of 1,500 square meters. The cylinders are stationary with no moving parts, and form a transit instrument with an instantaneous field of view of ~100 degrees by 1-2 degrees. Each CHIME Pathfinder cylinder has a feedline with 64 dual polarization feeds placed every ~30 cm which Nyquist sample the north-south sky over much of the frequency band. The signals from each dual-polarization feed are independently amplified, filtered to 400-800 MHz, and directly sampled at 800 MSps using 8 bits. The correlator is an FX design, where the Fourier transform channelization is performed in FPGAs, which are interfaced to a set of GPUs that compute the correlation matrix. The CHIME Pathfinder is a 1/10th scale prototype version of CHIME and is designed to detect the BAO feature and constrain the distance-redshift relation. The lessons learned from its implementation will be used to inform and improve the final CHIME design.

Bandura, Kevin; Addison, Graeme E.; Amiri, Mandana; Bond, J. Richard; Campbell-Wilson, Duncan; Connor, Liam; Cliche, Jean-François; Davis, Greg; Deng, Meiling; Denman, Nolan; Dobbs, Matt; Fandino, Mateus; Gibbs, Kenneth; Gilbert, Adam; Halpern, Mark; Hanna, David; Hincks, Adam D.; Hinshaw, Gary; Höfer, Carolin; Klages, Peter; Landecker, Tom L.; Masui, Kiyoshi; Mena Parra, Juan; Newburgh, Laura B.; Pen, Ue-li; Peterson, Jeffrey B.; Recnik, Andre; Shaw, J. Richard; Sigurdson, Kris; Sitwell, Mike; Smecher, Graeme; Smegal, Rick; Vanderlinde, Keith; Wiebe, Don

2014-07-01

95

Artificial Coral Reefs  

NSDL National Science Digital Library

Coral reefs are among the most diverse ecosystems on the planet...and the most threatened. Artificial reefs may help stem the loss of these valuable and beautiful habitats, with shipwrecks, old subway cars, and other structures taking the place of living coral or rocky outcrops. The following Web sites introduce artificial reefs, reef ecology, and some ongoing efforts to establish reef communities in the U.S. and beyond. PBS's NATURE offers a fascinating look at the artificial reefs created by the thousands of shipwrecks and downed planes from World War II that riddle the South Pacific (1). This is the companion Web site to the documentary War Wrecks of the Coral Seas, and it includes some great multimedia features. The next site comes from the National Oceanic and Atmospheric Administration and contains an excellent photo gallery of coral ecosystems around the world (2). The collection includes six pages of artificial reef photos taken in the Pacific. The following site comes from the online companion to the BBC's acclaimed documentary series The Blue Planet. Based on the episode The Web of Life, this site offers a fun, multimedia challenge for learning about and testing one's knowledge of coral reefs (3). The site includes a section on artificial reefs (click on Take it Further). Next, an August 2001 segment from National Public Radio's All Things Considered explores efforts to create artificial reefs using decommissioned New York City subway cars -- a project of Delaware's Department of Natural Resources and Environmental Control in the Division of Fish and Wildlife (4). Likewise, the non-profit group Artificial Reefs of the Keys is working to bring a de-commissioned military ship to the Florida Keys (5). The New Jersey Scuba Diver Web site provides an excellent introduction to artificial reef ecology; focused on reefs in New Jersey, of course. The mini-tutorial comes courtesy of William Figly, Principal Fisheries Biologist for the New Jersey Artificial Reef Program (6). The Fall 2001 issue of California Wild, the magazine of the California Academy of Sciences, addresses the benefits and concerns of off shore oil rigs becoming artificial reefs (7). Finally, visitors will find dozens of news articles and Web links related to artificial reefs in this entry, a page from the New England Artificial Reef Society Web site (8).

Sohmer, Rachel.

96

Coral Reef Ecosystems: The Abiotic Setting  

NSDL National Science Digital Library

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.

National Science Teachers Association (NSTA)

2006-11-01

97

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.

98

University of Tennessee Solar Pathfinder Site Analysis Map.................................................................................................................................................2  

E-print Network

University of Tennessee Solar Pathfinder Site Analysis July 2010 #12;1 Map, mainly parking lots and garages, for solar energy potential. The analysis was performed using a solar sites. All readings, except for UC plaza, were taken with the solar pathfinder at a height of eight feet

Wang, Xiaorui "Ray"

99

Monte-Carlo Fork Search for Cooperative Path-Finding  

E-print Network

), a new algorithm that solves Cooperative Path-Finding (CPF) problems with simultaneity. The background in the built tree. This idea fits CPF problems in which the branching factor is too large for MCTS or A agents. 1 Introduction Cooperative pathfinding (CPF) addresses the problem of finding paths for a set

Bouzy, Bruno

100

Pre-flight development of the PoGOLite Pathfinder  

E-print Network

, Sweden 2011 #12;#12;Doctoral Thesis in Physics Pre-flight development of the PoGOLite Pathfinder M 91 Stockholm, Sweden Stockholm, Sweden 2011 #12;Cover illustration: Stamps issued by the Swedish com- pared with simulations. The Pathfinder is being prepared for a maiden flight from northern Sweden

Haviland, David

101

Mars Pathfinder Wheel Abrasion Experiment Ground Test  

NASA Technical Reports Server (NTRS)

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.

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

1998-01-01

102

NOAA Coral Reef Watch Calcification Index of Coral Reef Ecosystems  

E-print Network

;Ocean `Acidification' pH CO3 2- CO2(aq) Wolf-Gladrow et al., 1999 www.niwascience + OHCO 22 -+ + 3HCOH32NOAA Coral Reef Watch Calcification Index of Coral Reef Ecosystems NOAANOAA''ss Coral Reef Watch:Coral) NOAA/NESDIS/STAR/SO and Coral Reef Conservation Program (CRCP) NOAA Coral Matrix Silver Spring

Kuligowski, Bob

103

Exploring the reefs Introduction  

E-print Network

. · Explain what factors affect the quality of a satellite image. #12;2 I. IKONOS Data The IKONOS data used chain. Many people depend on the reefs for food and economy (fish, shellfish, etc.). Coral reefs thrive include satellite images and any other data that are obtained by a hands-off observational approach. SONAR

Wright, Dawn Jeannine

104

Great Barrier Reef  

NASA Technical Reports Server (NTRS)

A better than average view of the Great Barrier Reef was captured by SeaWiFS on a recent overpass. There is sunglint northeast of the reef and there appears to be some sort of filamentous bloom in the Capricorn Channel.

2002-01-01

105

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...

106

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....

107

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...

108

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...

109

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...

110

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....

111

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.

112

The Coral Reef Environmental \\  

Microsoft Academic Search

Coral reefs have been increasingly reported as ecosystems in severe “crisis” and decline, with estimates of irreparably damaged reefs to be around 54%, and possible losses of 15-20% more over the next half-century. The urgency to mitigate these declines has increased in recent years as the effects of global climate change have become apparent alongside steadily increasing population pressures in

Bärbel G. Bischof

2010-01-01

113

Assessing the ‘deep reef refugia’ hypothesis: focus on Caribbean reefs  

Microsoft Academic Search

Coral reefs in shallow-water environments (<30 m) are in decline due to local and global anthropogenic stresses. This has\\u000a led to renewed interest in the ‘deep reef refugia’ hypothesis (DRRH), which stipulates that deep reef areas (1) are protected\\u000a or dampened from disturbances that affect shallow reef areas and (2) can provide a viable reproductive source for shallow\\u000a reef areas following

P. Bongaerts; T. Ridgway; E. M. Sampayo; O. Hoegh-Guldberg

2010-01-01

114

The Australian SKA Pathfinder (ASKAP) software architecture  

NASA Astrophysics Data System (ADS)

The Australian SKA Pathfinder (ASKAP) is a 1% Square Kilometre Array (SKA) pathfinder radio telescope, comprising of 36 12-metre diameter reflector antennas, each with a Focal Plane Array consisting of approximately 100 dualpolarised elements operating at centimetre wavelengths and yielding a wide field-of-view (FOV) on the sky of about 30 square degrees. ASKAP is currently under construction and will be located in the remote radio-quiet desert Midwest region of Western Australia. It is expected to be fully operational in 2013. Key challenges include near real-time processing of large amount of data (~ 4 GB/s), control and monitoring of widely distributed devices (approx. 150,000 monitoring I/O points) and remote semi-automated operations. After evaluating several software technologies we have decided to use the EPICS framework for the Telescope Operating System and the Internet Communications Engine (ICE) middleware for the high-level service bus. This paper presents a summary of the overall ASKAP software architecture, as well as describing how EPICS and ICE technologies fit in the control software design.

Guzman, Juan C.; Humphreys, Ben

2010-07-01

115

LISA Pathfinder Science Operations Concept and Development  

NASA Astrophysics Data System (ADS)

LISA Pathfinder is the second of the ESA Small Missions for Advanced Research in Technology, is a dedicated technology demonstrator for the joint ESA/NASA Laser Interferometer Space Antenna (LISA) mission. LISA Pathfinder carries two payloads, the European provided LISA Technology Package (LTP) and the NASA provided Disturbance Reduction System (DRS). The ground segment for LPF in the operational configuration will consist of one ground track-ing station, Cebreros (Spain), the Mission Operations Centre (MOC) at ESOC (Darmstadt, Germany), the Science Technology Operations Centre (STOC) located at ESOC and ESAC (Madrid, Spain) and LTP and DRS teams. The Science Technology Operations Centre although initially a small entity compatible with the operational requirements for an ESA SMART, has evolved in complexity in the last few years containing most of the systems and interfaces included as part of a normal ESA Science Operations Centre. In order to maintain a reasonable cost approach for its development and operations, a general reuse philosophy from systems already tested in previous ESA missions and/or from industry has been applied for the design and operation concept of the LPF STOC. The present paper describes the current LPF STOC design and it foreseen operational concept, highlighting the general reuse and customization process carried out for each of their individual subsystems.

Fauste, Jorge; McNamara, Paul; Armano, Michele; Texier, Damien; Freschi, Marco

116

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

PubMed

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

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

2014-06-15

117

Composition of the near-reef zooplankton at Heron Reef, Great Barrier Reef  

Microsoft Academic Search

Using a light trap, zooplankton was sampled at three stations at Heron Reef, Great Barrier Reef: (a) a typical patch reef in the Heron lagoon, (b) a site in 8 m water on the southern slope of Heron reef, and (c) a station approximately 300 m south of (b), in the open water of the channel between Heron and Wistari

P. F. Sale; P. S. McWilliam; D. T. Anderson

1976-01-01

118

New protection initiatives announced for coral reefs  

NASA Astrophysics Data System (ADS)

Off the coasts of some of the South Pacific's most idyllic-sounding atolls, Austin Bowden-Kerby has seen first-hand the heavy damage to coral reefs from dynamite and cyanide fishing. For instance, while snorkeling near Chuuk, an island in Micronesia, he has observed craters and rubble beds of coral, which locals have told him date to World War II ordnance.A marine biologist and project scientist for the Coral Gardens Initiative of the Foundation for the Peoples of the South Pacific, Bowden-Kerby has also identified what he says are some public health effects related to destroyed coral reefs and their dying fisheries. These problems include protein and vitamin A deficiency and blindness, all of which may—in some instances—be linked to poor nutrition resulting from lower reef fish consumption by islanders, according to Bowden-Kerby.

Showstack, Randy

119

CENSSIS SEABED: DIVERSE APPROACHES FORCENSSIS SEABED: DIVERSE APPROACHES FOR IMAGING SHALLOW AND DEEP CORAL REEFSIMAGING SHALLOW AND DEEP CORAL REEFS  

E-print Network

AND DEEP CORAL REEFSIMAGING SHALLOW AND DEEP CORAL REEFS Fernando Gilbes,Fernando Gilbes, Roy ArmstrongBED for the development of improved remote sensing techniques for monitoring coral reefs. SeaBED includes both controlled coral reef zones, different species, and coral health conditions with a submersible spectroradiometer

Gilbes, Fernando

120

The Imager for Mars Pathfinder Insurance Pan  

NASA Technical Reports Server (NTRS)

The Imager for Mars Pathfinder (IMP) obtained a full panorama of the Sagan Memorial Station landing site on Sol 2, before the IMP mast was deployed. The images in this panorama were taken in 4 filters (including stereo) and losslessly compressed to provide a high-quality multispectral survey of the landing site even if the IMP mast did not successfully deploy; this data set was therefore called the Insurance Pan. It was completed late in the afternoon of Sol 2, just before the IMP mast was (successfully) deployed. The data were stored in memory and returned to Earth after it became clear that downlink rates were higher than expected. The Insurance Pan horizontal (azimuth) coverage is nearly complete, with gaps caused by pointing errors and data packet losses. Stereo data were acquired in the blue (445 nm) filter, as well as right-eye green (531 nm), orange (600 nm), and near-infrared (752 nm) data.

Herkenhoff, K. E.; Johnson, J. R.; Weller, L. A.

2003-01-01

121

Statechart Analysis with Symbolic PathFinder  

NASA Technical Reports Server (NTRS)

We report here on our on-going work that addresses the automated analysis and test case generation for software systems modeled using multiple Statechart formalisms. The work is motivated by large programs such as NASA Exploration, that involve multiple systems that interact via safety-critical protocols and are designed with different Statechart variants. To verify these safety-critical systems, we have developed Polyglot, a framework for modeling and analysis of model-based software written using different Statechart formalisms. Polyglot uses a common intermediate representation with customizable Statechart semantics and leverages the analysis and test generation capabilities of the Symbolic PathFinder tool. Polyglot is used as follows: First, the structure of the Statechart model (expressed in Matlab Stateflow or Rational Rhapsody) is translated into a common intermediate representation (IR). The IR is then translated into Java code that represents the structure of the model. The semantics are provided as "pluggable" modules.

Pasareanu, Corina S.

2012-01-01

122

Modal analysis of PATHFINDER unmanned air vehicle  

SciTech Connect

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. Modal parameters were calculated, and animated mode shapes were produced using SMS STARStruct{trademark} Modal Analysis System software. The modal parameters will be used for validation of finite element models, optimum placement of onboard accelerometers during flight testing, and vibration isolation design of sensor platforms.

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

1994-10-19

123

Pathfinder autonomous rendezvous and docking project  

NASA Technical Reports Server (NTRS)

Capabilities are being developed and demonstrated to support manned and unmanned vehicle operations in lunar and planetary orbits. In this initial phase, primary emphasis is placed on definition of the system requirements for candidate Pathfinder mission applications and correlation of these system-level requirements with specific requirements. The FY-89 activities detailed are best characterized as foundation building. The majority of the efforts were dedicated to assessing the current state of the art, identifying desired elaborations and expansions to this level of development and charting a course that will realize the desired objectives in the future. Efforts are detailed across all work packages in developing those requirements and tools needed to test, refine, and validate basic autonomous rendezvous and docking elements.

Lamkin, Stephen (editor); Mccandless, Wayne (editor)

1990-01-01

124

Java PathFinder User Guide  

NASA Technical Reports Server (NTRS)

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.

Havelund, Klaus

1999-01-01

125

360 Degree Panorama Mars Pathfinder Landing Site  

NASA Technical Reports Server (NTRS)

This is the first contiguous, uniform 360-degree color panorama taken by the Imager for Mars Pathfinder (IMP) over the course of sols 8, 9, and 10 (Martian days). Different regions were imaged at different times over the three Martian days to acquire consistent lighting and shadow conditions for all areas of the panorama. At left is a lander petal and a metallic mast which is a portion of the low-gain antenna. On the horizon the double 'Twin Peaks' are visible, about 1-2 kilometers away. The rock 'Couch' is the dark, curved rock at right of Twin Peaks. Another lander petal is at left-center, showing the fully deployed forward ramp at far left, and rear ramp at right, which rover Sojourner used to descend to the surface of Mars on July 5. Immediately to the left of the rear ramp is the rock Barnacle Bill, which scientists found to be andesitic, possibly indicating that it is a volcanic rock (a true andesite) or a physical mixture of particles. Just beyond Barnacle Bill, rover tracks lead to Sojourner, shown using its Alpha Proton X-Ray Spectrometer (APXS) instrument to study the large rock Yogi. Yogi, low in quartz content, appears to be more primitive than Barnacle Bill, and appeared more like the common basalts found on Earth. The tracks and circular pattern in the soil leading up to Yogi were part of Sojourner's soil mechanics experiments, in which varying amounts of pressure were applied to the wheels in order to determine physical properties of the soil. During its traverse to Yogi the rover stirred the soil and exposed material from several centimeters in depth. During one of the turns to deploy Sojourner's Alpha Proton X-Ray Spectrometer, the wheels dug particularly deeply and exposed white material. Spectra of this white material show it is virtually identical to the rock Scooby Doo, and such white material may underlie much of the site. Deflated airbags are visible at the perimeter of all three lander petals. The IMP is a stereo imaging system with color capability provided by 24 selectable filters, twelve filters per 'eye.' Its red, green, and blue filters were used to take this image. The IMP, in its fully deployed configuration, 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, DC. 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.

1997-01-01

126

Mars Pathfinder Airbag Impact Attenuation System  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

127

The magnetic properties experiments on Mars Pathfinder  

NASA Astrophysics Data System (ADS)

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.

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

128

Exobiology site priorities for Mars Pathfinder  

NASA Technical Reports Server (NTRS)

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.

Farmer, Jack D.; Desmarais, David J.

1994-01-01

129

Coral Reef Ecosystems  

NASA Astrophysics Data System (ADS)

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.

Yap, Helen T.

130

Pathfinder aircraft taking off from ground - side view  

NASA Technical Reports Server (NTRS)

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.

1995-01-01

131

Pathfinder: Surface exploration, in-space operations and space transfer  

NASA Technical Reports Server (NTRS)

Viewgraphs on the Pathfinder program are presented. Information is given on technology needs, a planetary rover, program management, an autonomous lander, mission applications, orbital assembly, cryogenics, space nuclear reactors, space manufacturing, optical communications, spacecraft propulsion, aerobraking, and orbital transfer vehicles.

Mankins, John

1988-01-01

132

Launch Abort System Pathfinder Arrival - Duration: 1:48.  

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...

133

An overview of Miocene reefs  

SciTech Connect

Miocene reefs lived approximately within the latitudes of 27{degree}S to 48{degree}N compared with 25{degree}S and 32{degree}N for Holocene reefs. This expansion of reef-growing environments was the result of warm Miocene climates, aided by a eustatic sea level rise and tectonic styles that provided numerous foundations for reef development. The majority of Miocene reefs are found in three main areas: (1) Southeast Asia and the western Pacific, (2) the Mediterranean-Middle East, and (3) Middle America and the Caribbean. These regions, with their distinctive suites of coral and foramineral species, formed three biological provinces; respectively, they are the Indo-Pacific, Tethyan, and Western Atlantic provinces. Miocene reefs in Southeast Asia occur in several foreland basins as patch reef complexes on paleohighs and as barrier reefs in back-arc basins. Those reefs in the Mediterranean occur as fringing reefs, middle-shelf patch reefs, or as barrier reefs on the edges of tectonic blocks associated with Alpine thrust belts. Most reefs in the Caribbean grew on isolated open-ocean highs of volcanic origin. Miocene reefs display a diversity of framework types: (1) coral-encrusting, red algal boundstones with diverse coral faunas, (2) branching coral-encrusting, red algal boundstones with a limited Poritid fauna, (3) encrusting red algal boundstones. Barrier reef systems are especially rich in encrusting red algae and robust corals; grainstones are common as interbedded sediment. Patch reef complexes, however, display muddy carbonate textures, may have less diverse coral faunas, and commonly have larger foraminifera. The global distribution of Miocene reefs is important because (1) it provides insight into a paleoclimatic view of the earth during a major greenhouse stage and (2) Miocene buildups, such as the Arun (EUR of 14 tcf) and Bima fields (EUR of about 100 MMBO), are exploration targets.

Jordan, C.F. Jr. (Mobil Research and Development Corp., Dallas, TX (USA)); Colgan, M.W. (College of Charleston, SC (USA)); Frost, S.H. (Unocal, Los Angeles, CA (USA)); Glenn, E.C. (Phillips Petroleum, Bartlesville, OK (USA)); Bosence, D. (Royal Holloway and Bedford New College, Egham (England)); Esteban, M. (ERICO Petroleum Information Ltd., London (England))

1990-05-01

134

Analyzing the Effects of Climate Change on Sea Surface Temperature in Monitoring Coral Reef Health in the Florida Keys Using Sea Surface Temperature Data  

NASA Technical Reports Server (NTRS)

This presentation discusses use of 4 kilometer satellite-based sea surface temperature (SST) data to monitor and assess coral reef areas of the Florida Keys. There are growing concerns about the impacts of climate change on coral reef systems throughout the world. Satellite remote sensing technology is being used for monitoring coral reef areas with the goal of understanding the climatic and oceanic changes that can lead to coral bleaching events. Elevated SST is a well-documented cause of coral bleaching events. Some coral monitoring studies have used 50 km data from the Advanced Very High Resolution Radiometer (AVHRR) to study the relationships of sea surface temperature anomalies to bleaching events. In partnership with NOAA's Office of National Marine Sanctuaries and the University of South Florida's Institute for Marine Remote Sensing, this project utilized higher resolution SST data from the Terra's Moderate Resolution Imaging Spectroradiometer (MODIS) and AVHRR. SST data for 2000-2010 was employed to compute sea surface temperature anomalies within the study area. The 4 km SST anomaly products enabled visualization of SST levels for known coral bleaching events from 2000-2010.

Jones, Jason; Burbank, Renane; Billiot, Amanda; Schultz, Logan

2011-01-01

135

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

NASA Astrophysics Data System (ADS)

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.

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

136

Reefs at risk.  

PubMed

Coral reefs, considered the rainforests of the seas, are home to a diverse number of marine species. These reefs are tightly woven ecosystems with complex linkages, which, if disturbed, result in an unpleasant chain of events. Furthermore, these reefs are the main source of animal protein for more than a billion people. Aside from supplying food, they stabilize shorelines and protect the land from rising seas and storm damage. Also, they provide sources of medicines used for bone grafts and treatment for certain viruses. However, these reefs are in danger of being permanently damaged as a result of natural and man-made forces. In response to this threat, most marine scientists have suggested that local communities be involved in the implementation and management of programs, with the aim of achieving sustainable reef maintenance. In addition, international agencies have taken the initiative to finance such programs to ensure their continuity. Overall, the management and development of coastal ecosystems depend on how they are managed and not on how they are being exploited. Resources must be rebuilt and their protection ensured for future generations. PMID:12322541

Hinrichsen, D

1999-01-01

137

Coral reef hydrogeology  

SciTech Connect

Knowledge of internal flow velocities and pore water residence time is important in understanding pore water geochemistry, nutrient fluxes at the benthic boundary, reef diagenesis, and fresh water resources in reef islands. Hydrogeologic studies of Pacific and Indian Ocean reef and atoll islands indicate a dual aquifer systems; the major Pleistocene aquifer has hydraulic conductivities on the order of 1000 m/d, while the overlying Holocene aquifer of unconsolidated sediments is at least an order of magnitude less permeable. The high permeability in the Pleistocene formation is the result of large voids, both constructional and from subaerial solution during low stands of the sea. Wind, wave and tide induced head differences ranging from a few centimeters to several tens of centimeters provide the driving force for internal flow. Pore water residence times and geochemistry will vary greatly, depending on whether the water is in a major flow channel or in more restricted pores. Studies of both submerged reefs and atoll islands give bulk pore water residence times on the order of months to a few years. Chemical analyses of pore water indicate that both carbonate solution and precipitation are taking place, which will alter porosity and permeability with time. The dual aquifer model also suggests that the Ghyben-Herzberg lens approach to reef island fresh water resources is inaccurate and can lead to a gross overestimation of the potable resource. 18 refs., 5 figs.

Buddemeier, R.W.; Oberdorfer, J.A.

1985-05-21

138

Evolution: Survival: Coral Reef Connections  

NSDL National Science Digital Library

The representation depicts the variety of organisms living near a coral reef and their relationships to one another. The interactive resource allows the user to move to different areas of the reef and select information about particular organisms, including relationships of "predation and parasitism," "competition," "commensalism and mutualism" at each reef zone.

139

The future of coral reefs  

Microsoft Academic Search

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

Nancy Knowlton

2001-01-01

140

Bayesian model selection for LISA pathfinder  

NASA Astrophysics Data System (ADS)

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.

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

141

Bayesian Model Selection for LISA Pathfinder  

E-print Network

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 on-board 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 where 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.

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

2014-06-05

142

Data Analysis for the LISA Pathfinder Mission  

NASA Technical Reports Server (NTRS)

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.

Thorpe, James Ira

2009-01-01

143

The Mars Pathfinder Mission and Science Results  

NASA Technical Reports Server (NTRS)

Mars Pathfinder, the first low-cost, quick Discovery class mission to be completed, successfully landed on the surface of Mars on July 4, 1997, deployed and navigated a small rover, and collected data from 3 science instruments and 10 technology experiments. The mission operated on Mars for 3 months and returned 2.3 Gbits of new data, including over 16,500 lander and 550 rover images, 16 chemical analyses of rocks and soil, and 8.5 million individual temperature, pressure and wind measurements. The rover traversed 100 m clockwise around the lander, exploring about 200 square meters of the surface. The mission captured the imagination of the public, and garnered front page headlines during the first week. A total of about 566 million internet "hits" were registered during the first month of the mission, with 47 million "hits" on July 8th alone, making the Pathfinder landing by far the largest internet event in history at the time. Pathfinder was the first mission to deploy a rover on Mars. It carried a chemical analysis instrument, to characterize the rocks and soils in a landing area over hundreds of square meters on Mars, which provided a calibration point or "ground truth" for orbital remote sensing observations. The combination of spectral imaging of the landing area by the lander camera, chemical analyses aboard the rover, and close-up imaging of colors, textures and fabrics with the rover cameras offered the potential of identifying rocks (petrology and mineralogy). With this payload, a landing site in Ares Vallis was selected because it appeared acceptably safe and offered the prospect of analyzing a variety of rock types expected to be deposited by catastrophic floods, which enabled addressing first-order scientific questions such as differentiation of the crust, the development of weathering products, and the nature of the early Martian environment and its subsequent evolution. The 3 instruments and rover allowed seven areas of scientific investigation: the geology and geomorphology of the surface, mineralogy and geochemistry of rocks and soils, physical properties of surface materials, magnetic properties of airborne dust, atmospheric science including aerosols, and rotational and orbital dynamics of Mars. Scientists were assembled into 7 Science Operations Groups that were responsible for requesting measurements by the 3 instruments, rover and engineering subsystems for carrying out their scientific investigations and for analyzing the data and reporting on their findings. The spacecraft was launched on December 4, 1996 and had a 7 month cruise to Mars, with four trajectory correction maneuvers. The vehicle entered the atmosphere directly following cruise stage separation. Parachute deployment, heatshield and lander separation, radar ground acquisition, airbag inflation and rocket ignition all occurred before landing at 2:58 AM true local solar time (9:56:55 AM PDT). The lander bounced at least 15 times up to 12 in high without airbag rupture, demonstrating the robustness of this landing system. Reconstruction of the final landing sequence indicates that the parachute/backshel1/1ander was tilted due to a northwest directed wind and wind shear, which resulted in the lander bouncing about I km to the northwest and initially downhill about 20 m from where the solid rockets fired. Two anomalously bright spots located in the lander scene are likely the heatshield, which continued in a ballistic trajectory about 2 km downrange (west southwest), and the backshell/parachute, which stayed nearer to where the rockets fired. Unconnected disturbed soil patches in the scene indicate that the final few bounces of the lander were from the east-southeast and were followed by a gentle roll to the west before coming to rest on the base petal. The location of the lander away from where the solid rockets fired and considerations of the exhaust products used to inflate the airbags and their fate, indicate that the Pathfinder landing system is one of the cleanest designed leaving the local area essentia

Golombek, M. P.

1999-01-01

144

Data Analysis for the LISA Pathfinder Mission  

NASA Astrophysics Data System (ADS)

As the launch time of LISA Pathfinder draws near, there is increasing effort being employed on the preparation and development of the on-board experiments and their associated data analysis procedures. Due to the relatively short duration of the mission, and because of the large number of investigations we wish to perform, the on-line analysis and assessment of each investigation is essential for the successful planning of the mission time-line. In the past, the data analysis effort has focussed on developing a software environment (LTPDA) that is both robust and flexible. The software also needs to meet other requirements arising from operational and scientific constraints. LTPDA is in a mature state now and a brief report will be given in this talk. The team is now focussed on the development of the experiments to be performed on orbit. This involves developing the tele-command sequences needed to perform the experiments, the development of the data analysis procedures and algorithms required to analyse each experiment, and the validation of the full chain using LPF simulators. This talk will review the entire data analysis effort and present an overview of the planned experiments in the context of data analysis.

Hewitson, Martin

2012-07-01

145

Postglacial Fringing-Reef to Barrier-Reef conversion on Tahiti links Darwin's reef types  

PubMed Central

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

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

146

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

PubMed

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

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

147

Postglacial Fringing-Reef to Barrier-Reef conversion on Tahiti links Darwin's reef types  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

148

Gray's Reef Research  

NSDL National Science Digital Library

Provides a sampling of research projects conducted at the Gray's Reef National Marine Sanctuary off Georgia's Sapelo Island. Projects range from geology to trawling impacts on the seafloor, estimating fish populations by video transect, Sanctuary monitoring using data buoys, sidescan sonar and other technologies. Examples of current projects: conducting a study on the movement patterns of fish in the area; efforts to understand the roles of "choices" fishes might make in their behaviors, and its impact on diversity of species found in reef fish communities and a study designed to inventory the invertebrates and fish communities and analyze how those communities are impacted by fishing activities. Appropriate for grades 9 and up.

149

Reef talus: A popular misconception  

NASA Astrophysics Data System (ADS)

Reef fronts have traditionally been regarded as comprising debris derived by contemporaneous erosion of 'the reef'. However, evidence from wave transport indicates that on present-day reefs the bulk of the debris generated in this way accumulates in the back-reef area, with only finer-grained sediment carried off-reef by retreating flows or by overwash. Nevertheless, in contrast to this observation, 'fore-reef' debris slopes are commonly considered "characteristic" of Phanerozoic reefs. This apparent error reflects the conflation of processes defining contemporary growth and accretion of the reef, and the corresponding long-term accretion of the carbonate platform on which it rests. Present-day reefs are commonly (although not exclusively) additions to long-lived carbonate platforms. Growth of the latter is intermittent and has been moderated by changes in sea-level that, for recent reefs, have been on time scales of less than 100 ka. During low sea-level stands, growth ceases or is translated downslope and earlier deposits are subject to lithification and subaerial erosion. Similar changes are applied on a larger scale to the aggrading growth of carbonate platforms, but the bulk accretion of these includes quite different processes and reflects far longer timescales. During low sea-level stands, the margins of platforms commonly become unstable, with instability reflected in slope failure and in the shedding of blocks, ranging from metres to kilometres in diameter, associated with the generation of debris flows and turbidites. It is argued that these are the materials that are commonly described as 'reef talus' in ancient structures, although their formation is largely independent of any contemporary reef growth. Difficulties arise where 'the reef' and 'the platform' are treated as a single functional entity. It is important to recognize the conceptual distinction between them, 'reef talus' is a misleading description of the debris predominantly generated by platform erosion and slope failure.

Braithwaite, Colin J. R.

2014-01-01

150

Coral records of reef-water pH across the central Great Barrier Reef, Australia: assessing the influence of river runoff on inshore reefs  

NASA Astrophysics Data System (ADS)

The boron isotopic (?11Bcarb) compositions of long-lived Porites coral are used to reconstruct reef-water pH across the central Great Barrier Reef (GBR) and assess the impact of river runoff on inshore reefs. For the period from 1940 to 2009, corals from both inner as well as mid-shelf sites exhibit the same overall decrease in ?11Bcarb of 0.086 ± 0.033‰ per decade, equivalent to a~decline in seawater pH (pHsw) of ~ 0.017 ± 0.007 pH units per decade. This decline is consistent with the long-term effects of ocean acidification based on estimates of CO2 uptake by surface waters due to rising atmospheric levels. We also find that compared to the mid-shelf corals, the ?11Bcarb compositions for inner shelf corals subject to river discharge events, have higher and more variable values and hence higher inferred pHsw values. These higher ?11Bcarb values for inner-shelf corals are particularly evident during wet years, despite river waters having lower pH. The main effect of river discharge on reef-water carbonate chemistry thus appears to be from higher nutrients driving increased phytoplankton productivity, resulting in the drawdown of pCO2 and increase in pHsw. Increased primary production therefore has the potential to counter the more transient effects of low pH river water (pHrw) discharged into near-shore environments. Importantly however, inshore reefs also show a consistent pattern of sharply declining coral growth that coincides with periods of high river discharge. This occurs despite these reefs having higher pHsw values and hence higher seawater aragonite saturation states, demonstrating the over-riding importance of local reef-water quality on coral reef health.

D'Olivo, J. P.; McCulloch, M. T.; Eggins, S. M.; Trotter, J.

2014-07-01

151

Sponge distribution across Davies Reef, Great Barrier Reef, relative to location, depth, and water movement  

Microsoft Academic Search

Sponge populations were surveyed at different depths in three zones of Davies Reef, a large platform reef of the central Great Barrier Reef. Depth is the major discriminatory factor as few sponges are found within the first 10 m depth and maximal populations occur between 15 m and 30 m on fore-reef, lagoon and back-reef slopes. Reef location is another

Clive R. Wilkinson; Elizabeth Evans

1989-01-01

152

MONITORING FRINGING CORAL REEFS FOR HUMAN IMPACTS  

Microsoft Academic Search

The Whitsunday Islands are the largest group of continental islands inside the Great Barrier Reef, with highly diverse fringing coral reefs. Their biology is still poorly understood. The reefs are heavily utilised by commercial tourism, yachts, fishermen and divers. Paradoxically, the desire to present the prettiest coral reefs to visiting divers focuses anchor damage onto the richest reefs. This chronic

James P. Thompson

1990-01-01

153

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...

154

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...

155

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

156

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

157

The Status of the Ultra Fast Flash Observatory - Pathfinder  

NASA Astrophysics Data System (ADS)

The Ultra Fast Flash Observatory (UFFO) is a project to study early optical emissions from Gamma Ray Bursts (GRBs). The primary scientific goal of UFFO is to see if GRBs can be calibrated with their rising times, so that they could be used as new standard candles. In order to minimize delay in optical follow-up measurements, which is now about 100 sec after trigger from the Swift experiment, we rotate a mirror to redirect light path so that optical measurement can be performed within a second after the trigger. We have developed a pathfinder mission, UFFO-pathfinder to launch on board the Lomonosov satellite in 2012. In this talk, I will present scientific motivations and descriptions of the design and development of UFFO-pathfinder.

Nam, J. W.; Ahmad, S.; Ahn, K. B.; Barrillon, P.; Brandt, S.; Budtz-Jrgensen, C.; Castro-Tirado, A. J.; Chang, C.-H.; Chang, C.-Y.; Chang, Y. Y.; Chen, C. R.; Chen, P.; Cho, M.; Choi, H. S.; Choi, Y. J.; Connel, P.; Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Huang, J. J.; Huang, M. H. A.; Jeong, S.; Jung, A.; Kim, J. E.; Kim, M. B.; Kim, S.-W.; Kim, Y. W.; Krasnov, A. S.; Lee, J.; Lim, H.; Linder, E. V.; Liu, T. C.; Lund, N.; Min, K. W.; Na, G. W.; Panasyuk, M. I.; Park, I. H.; Reglero, V.; Ripa, J.; Rodrigo, J. M.; Smoot, G. F.; Suh, J. E.; Svertilov, S.; Vedenkin, N.; Wang, M.-Z.; Yashin, I.

2014-01-01

158

Miocene reefs in western Mediterranean  

SciTech Connect

Coral reefs were particularly abundant and well developed during the late Tortonian and Messinian in southeastern Spain, the Balearic Islands, Italy, Sicily, Algeria, and Morocco. These reefs occurred just before and during the deposition of the thick Messinian evaporite units in the basinal areas and disappeared completely from Mediteranean during the early Pliocene. Most of the coral reefs are fringing terrigenous coastal fan complexes with very small lagoons and show progradation of less than 2 km. Some of the reefs occur on, or are intercalated with, Neogene volcanics or Messinian evaporites. Barrier-reef complexes are less common, have extensive lagoons behind them, and show complex progradational geometries more than 10 km wide. Excellent outcrops allow detailed reconstruction of paleogeography and sea level changes. Progradation predominated during phases of relative sea level drops and stillsands, while significant retrogradation occurred during sea level rises. The coral reef wall framework is commonly less than 20 m thick and is dominated by Porites and, locally, Tarbellastrae. Older Miocene reefs are less well developed, but show greater diversity of corals and reef organisms. Younger Miocene reef complexes occurring in open ocean settings are formed by only one branching coral genus (Porites or, locally, Tarbellastraea) with branching colonies up to 7 m high. Halimeda sands are particularly abundant in the upper reef slopes with occasional intercalations of red algae pavements that most likely coincide with episodes of terrigenous influx.

Esteban, M.

1988-01-01

159

Box model analysis for the estimation of the water mass transport in coral reef region, Japan  

Microsoft Academic Search

Sekisei lagoon is the largest coral reef region, with a radius of 20 km, in Japan (between Ishigaki Island and Iriomote Island in Okinawa Prefecture), and suffered damage to only about 30% of its corals when the worldwide coral bleaching occurred in 1998. The water exchange of a coral reef region is an important environmental factor affecting the health, growth,

Susumu Kanno; Yasuo Furushima; M. Okamoto; S. Murakami

2002-01-01

160

Atmosphere structure and meteorology instrument for Mars Pathfinder  

NASA Technical Reports Server (NTRS)

The MESUR Science Definition Team recommended that all MESUR probes, including Pathfinder, carry an ASI/MET experiment, in order that no opportunity be lost to characterize the atmosphere of Mars in passing through it. The experiment was thus included on Pathfinder from the start (February 1992), but on an essentially noninterference basis: It was to make no unusual demands on the spacecraft. A Science Advisory Team was appointed by NASA Headquarters in September 1993 first met on November 3rd to initiate formal science participation, and the level of activity has since been high. The instrument passed its Preliminary Design Review on February 28th.

Seiff, Alvin

1994-01-01

161

MARS PATHFINDER AIR BAG INSTALLATION IN SAEF-2  

NASA Technical Reports Server (NTRS)

In the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2), the Jet Propulsion Laboratory (JPL) team installs air bags on the Mars Pathfinder lander. The four airbags will cushion the lander as it touches down on the Martian surface, protecting the delicate instruments and Surveyor small rover inside the tetrahedral-shaped lander. The Mars Pathfinder is one of two Mars-bound spacecraft being prepared for launch this fall. Liftoff is set for Dec. 2 at the beginning of a 24-day launch period.

1996-01-01

162

Reef Fishes of Saba Bank, Netherlands Antilles: Assemblage Structure across a Gradient of Habitat Types  

PubMed Central

Saba Bank is a 2,200 km2 submerged carbonate platform in the northeastern Caribbean Sea off Saba Island, Netherlands Antilles. The presence of reef-like geomorphic features and significant shelf edge coral development on Saba Bank have led to the conclusion that it is an actively growing, though wholly submerged, coral reef atoll. However, little information exists on the composition of benthic communities or associated reef fish assemblages of Saba Bank. We selected a 40 km2 area of the bank for an exploratory study. Habitat and reef fish assemblages were investigated in five shallow-water benthic habitat types that form a gradient from Saba Bank shelf edge to lagoon. Significant coral cover was restricted to fore reef habitat (average cover 11.5%) and outer reef flat habitat (2.4%) and declined to near zero in habitats of the central lagoon zone. Macroalgae dominated benthic cover in all habitats (average cover: 32.5 – 48.1%) but dominant algal genera differed among habitats. A total of 97 fish species were recorded. The composition of Saba Bank fish assemblages differed among habitat types. Highest fish density and diversity occurred in the outer reef flat, fore reef and inner reef flat habitats. Biomass estimates for commercially valued species in the reef zone (fore reef and reef flat habitats) ranged between 52 and 83 g/m2. The composition of Saba Bank fish assemblages reflects the absence of important nursery habitats, as well as the effects of past fishing. The relatively high abundance of large predatory fish (i.e. groupers and sharks), which is generally considered an indicator of good ecosystem health for tropical reef systems, shows that an intact trophic network is still present on Saba Bank. PMID:20502637

Toller, Wes; Debrot, Adolphe O.; Vermeij, Mark J. A.; Hoetjes, Paul C.

2010-01-01

163

LISA Pathfinder and eLISA news  

NASA Technical Reports Server (NTRS)

Two important gatherings of the space-based gravitational-wave detector community were held in Zurich, Switzerland this past March. The first was a meeting of the Science Working Team for LISA Pathfinder (LPF), a dedicated technology demonstrator mission for a future LISA-like gravitational wave observatory. LPF is entering an extremely exciting phase with launch less than 15 months away. All flight components for both the European science payload, known as the LISA Technology Package (LTP), and the NASA science payload, known as the Space Technology 7 Disturbance Reduction System (ST7-DRS), have been delivered and are undergoing integration. The final flight component for the spacecraft bus, a cold-gas thruster based on the successful GAIA design, will be delivered later this year. Current focus is on completing integration of the science payload (see Figures 1 and 2) and preparation for operations and data analysis. After a launch in Summer 2015, LPF will take approximately 90 days to reach its operational orbit around the Earth-Sun Lagrange point (L1), where it will begin science operations. After 90 days of LTP operations followed by 90 days of DRS operations, LPF will have completed its prime mission of paving the way for a space-based observatory of gravitational waves in the milliHertz band. Immediately following the meeting of the LPF team, the eLISA consortium held its third progress meeting. The consortium (www.elisascience.org) is the organizing body of the European space-based gravitational-wave community, and it was responsible for the "The Gravitational Universe" whitepaper that resulted in the November 2013 election of a gravitational-wave science theme for ESA's Cosmic Visions L3 opportunity. In preparation for an L3 mission concept call, which is expected later this decade, and for launch in the mid 2030s, the eLISA consortium members are coordinating technology development and mission study activities which will build on the LPF results. The final mission concept is expected to include some international (non-European) contributions, and NASA has expressed an interest in participating in this ground-breaking mission. The US research community supports such a collaboration, or any other mission scenario that achieves the high-priority science of a space-based gravitational-wave observatory at the earliest possible date.

Thorpe, James Ira; Mueller, Guido

2014-01-01

164

Future launcher demonstrator. Challenge and pathfinder  

NASA Astrophysics Data System (ADS)

For future and advanced launch vehicles emphasis is focused on single-stage-to-orbit (SSTO) concepts and on completely reusable versions with the goal to reduce the recurrent launch cost, to improve the mission success probability and also safety for the space transportation of economically attractive payloads into Low Earth Orbit. Both issues, the SSTO launcher and the low cost reusability are extremely challenging and cannot be proven by studies and on-ground tests alone. In-flight demonstration tests are required to verify the assumptions and the new technologies, and to justify the new launcher-and operations-concepts. Because a number of SSTO launch vehicles are currently under discussion in terms of configurations and concepts such as winged vehicles for vertical or horizontal launch and landing (from ground or a flying platform), or wingless vehicles for vertical take-off and landing, and also in terms of propulsion (pure rockets or a combination of air breathing and rocket engines), an experimental demonstrator vehicle appears necessary in order to serve as a pathfinder in this area of multiple challenges. A suborbital Reusable Rocket Launcher Demonstrator (RRLD) has been studied recently by a European industrial team for ESA. This is a multipurpose, evolutionary demonstrator, conceived around a modular approach of incremental improvements of subsystems and materials, to achieve a better propellant mass fraction i.e. a better performance, and specifically for the accomplishment of an incremental flight test programme. While the RRLD basic test programme will acquire knowledge about hypersonic flight, re-entry and landing of a cryogenic rocket propelled launcher — and the low cost reusability (short turnaround on ground) in the utilization programme beyond basic testing, the RRLD will serve as a test bed for generic testing of technologies required for the realization of an SSTO launcher. This paper will present the results of the European RRLD study which proposes a winged suborbital rocket launcher operations & technology demonstrator for vertical take-off and horizontal landing — using primarily conventional technology and materials as a first step towards the challenging goal of a reusable SSTO ETO launch vehicle.

Kleinau, W.; Guerra, L.; Parkinson, R. C.; Lieberherr, J. F.

1996-02-01

165

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

NASA Astrophysics Data System (ADS)

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.

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

2013-03-01

166

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.

167

Oceanic forcing of coral reefs.  

PubMed

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

Lowe, Ryan J; Falter, James L

2015-01-01

168

The Paleoecology of Coral Reefs  

Microsoft Academic Search

\\u000a Reefs are one of the oldest ecosystems in the world, and coral reefs have had a rich and varied history over hundreds of millions\\u000a of years. The long-term history of living reef organisms provides an essential window in which to view a number of fundamental\\u000a evolutionary and ecological processes over extended time frames not available to modern ecology over years

John M. Pandolfi

169

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.

170

Modis, SeaWIFS, and Pathfinder funded activities  

NASA Technical Reports Server (NTRS)

MODIS (Moderate Resolution Imaging Spectrometer), SeaWIFS (Sea-viewing Wide Field Sensor), Pathfinder, and DSP (Digital Signal Processor) objectives are summarized. An overview of current progress is given for the automatic processing database, client/server status, matchup database, and DSP support.

Evans, Robert H.

1995-01-01

171

Mars Pathfinder Mission Internet-Based Operations Using WITS  

Microsoft Academic Search

The Web Interface for Telescience (WITS) is an Internet-based tool that the Mars Pathfinder mission used for both mission operations at JPL and public outreach. WITS enables the viewing of downlinked im- ages and results in various ways, terrain feature mea- surement and annotation, and planning of daily mis- sion activities. WITS is written in the Java language and is

Paul G. Backes; Kam S. Tso; Gregory K. Tharp

1998-01-01

172

Re-examination of Mars Pathfinder parachute drag coefficient estimate  

NASA Technical Reports Server (NTRS)

The Mars Exploration Rover (MER) mission utilizes the Mars Pathfinder (MPF) parachute design. The MPF parachute drag coefficient is a driver for the MER entry, descent, and landing (EDL) design. As a result, a good estimate of the performance of the MPF parachute at Mars is required.

Desai, P.; Schofield, T.; Lisano, M.

2003-01-01

173

Pathfinder wing tip video at 50,000 feet  

NASA Technical Reports Server (NTRS)

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.

1995-01-01

174

A Pathfinder for Animal Research and Animal Rights.  

ERIC Educational Resources Information Center

This pathfinder was originally prepared for "Biomedical Research and Animal Rights," a session sponsored by the Veterinary Medical Libraries and Research Libraries Sections of the Medical Library Association. Current resources are described, from bibliographies to electronic bulletin boards, which relate to the issue of laboratory animal welfare…

Anderson, David C.

1992-01-01

175

Online pathfinders : Toward an experience-centered model  

Microsoft Academic Search

Purpose – Looks at the pathfinder approach to library instruction, which was developed in the 1960s by Patricia Knapp. Knapp's system focused, not on the simple provision of answers to questions, but on the teaching of the effective use of the library and its resources– in other words, on the finding of one's “way” in the library. Design\\/methodology\\/approach – A

William Hemmig

2005-01-01

176

Pathfinder Meets DB2 Relational XQuery Optimization Techniques  

E-print Network

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

Grust, Torsten

177

Teacher job satisfaction: lessons from the TSW Pathfinder Project  

Microsoft Academic Search

Government policy assumes that modernization and remodelling will be effective as external intervention mechanisms to improve job satisfaction. Based on data collected as part of the evaluation of the ‘Transforming the School Workforce Pathfinder Project’, an argument is presented here which suggests that internal management models may be more effective in improving teacher job satisfaction. By comparing the responses of

Graham Butt; Ann Lance; Antony Fielding; Helen Gunter; Steve Rayner; Hywel Thomas

2005-01-01

178

Teacher Job Satisfaction: Lessons from the TSW Pathfinder Project  

ERIC Educational Resources Information Center

Government policy assumes that modernization and remodelling will be effective as external intervention mechanisms to improve job satisfaction. Based on data collected as part of the evaluation of the "Transforming the School Workforce Pathfinder Project", an argument is presented here which suggests that internal management models may be more…

Butt, Graham; Lance, Ann; Fielding, Antony; Gunter, Helen; Rayner, Steve; Thomas, Hywel

2005-01-01

179

Mars Suface Layer Climatology from Viking and Pathfinder  

Microsoft Academic Search

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

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

2003-01-01

180

Concept Mapping in Pulmonary Physiology Using Pathfinder Scaling  

Microsoft Academic Search

This three-part article begins with a brief presentation of a framework that describes different approaches to conduct and report research on expert knowledge. The framework contrasts direct vs. indirect approaches and provides examples of each. Second, the article gives a detailed description of the methods and results of three concept mapping studies in pulmonary physiology that employ Pathfinder scaling, an

William C. McGaghie; Donald R. McCrimmon; Gordon Mitchell; Jason A. Thompson

2004-01-01

181

Results of the Imager for Mars Pathfinder Windsock Experiment  

NASA Technical Reports Server (NTRS)

The IMP windsock experiment measured wind speeds at three heights within 1.2 m of the martian surface during Pathfinder landed operations. Data from the strongest breezes indicate aerodynamic roughness = 3 cm, wind friction speeds up to 1 m/sec.

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

2000-01-01

182

LISA Pathfinder: the geodesy explorer testing alternative theories of gravity  

NASA Astrophysics Data System (ADS)

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.

Armano, Michele

183

Digital Reef Rugosity Estimates Coral Reef Habitat Complexity  

PubMed Central

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

Dustan, Phillip; Doherty, Orla; Pardede, Shinta

2013-01-01

184

Coral reefs on the edge? Carbon chemistry on inshore reefs of the great barrier reef.  

PubMed

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

Uthicke, Sven; Furnas, Miles; Lønborg, Christian

2014-01-01

185

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

PubMed Central

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

Uthicke, Sven; Furnas, Miles; Lønborg, Christian

2014-01-01

186

Results of the Imager for Mars Pathfinder windsock experiment  

USGS Publications Warehouse

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.

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

2000-01-01

187

Coral reefs and carbon dioxide  

SciTech Connect

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.

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

1996-03-01

188

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....

189

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....

190

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....

191

Coral Reef Recovery from Hurricane Damage and Implications of Coral Reefs for Future Medical Discoveries  

Microsoft Academic Search

Recent experimentation has found soft corals and sponges to have potential medical uses in treating cancer and other diseases. Research was conducted via underwater transect data collection using SCUBA on several coral reefs in Cozumel, Mexico, approximately three years after hurricane Wilma destroyed much of the reef. Three 100 m linear transects of fore reef, hind reef and reef crest

Katelyn Mescher; Ashley Sturgess

2009-01-01

192

Functional versatility supports coral reef biodiversity  

E-print Network

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

Wainwright, Peter C.

193

PBS Online NewsHour: Coral Reefs  

NSDL National Science Digital Library

In-depth coverage of the role of coral reefs in environment, medicinal properties, and conservation efforts, together with instructional materials. Includes lesson plan; interactive on coral-reef building blocks; extended interviews; and stories on reef threats, international treaties, Caribbean reefs, mangrove shields, and the Aquarius undersea lab. Main story is provided as text, streaming video, and RealAudio.

194

Coral reef protection  

NASA Astrophysics Data System (ADS)

The National Oceanic and Atmospheric Administration announced the establishment on 13 November of the first U.S. zone to protect a sensitive coral reef area from potential damage by ships.The Florida Keys' Particularly Sensitive Sea Area, just one of a handful of such areas globally, has been designated by the International Maritime Organization, a specialized agency of the United Nations. The area protects a zone of more than 3,000 square nautical miles stretching from the Biscayne National Park to the Dry Tortugas.

Showstack, Randy

195

Capitol Reef National Park  

NSDL National Science Digital Library

This National Park Service (NPS) website provides an in-depth look at Capitol Reef National Park in Utah. Specifically, this covers the geology and natural resources of the park. There is a general overview of the geology of this area including the Waterpocket fold, Colorado Plateau, Cathedral Valley and erosion. There is a description of various rock colors and how they form, as well as a detailed stratigraphic column illustrating the names, thicknesses, and ancient environments of rocks and formations that exist in the park. The Natural Resources section discusses some of the history and archeology of the park, as well as birds, mammals, plants, reptiles and environmental problems.

196

Interface Generation and Compositional Verification in JavaPathfinder  

NASA Technical Reports Server (NTRS)

We present a novel algorithm for interface generation of software components. Given a component, our algorithm uses learning techniques to compute a permissive interface representing legal usage of the component. Unlike our previous work, this algorithm does not require knowledge about the component s environment. Furthermore, in contrast to other related approaches, our algorithm computes permissive interfaces even in the presence of non-determinism in the component. Our algorithm is implemented in the JavaPathfinder model checking framework for UML statechart components. We have also added support for automated assume-guarantee style compositional verification in JavaPathfinder, using component interfaces. We report on the application of the presented approach to the generation of interfaces for flight software components.

Giannakopoulou, Dimitra; Pasareanu, Corina

2009-01-01

197

The LISA Pathfinder Mission. Tracing Einstein's Geodesics in Space  

NASA Astrophysics Data System (ADS)

LISA Pathfinder, formerly known as SMART-2, is the second of the European Space Agency’s Small Missions for Advance Research and Technology, and is designed to pave the way for the joint ESA/NASA Laser Interferometer Space Antenna (LISA) mission, by testing the core assumption of gravitational wave detection and general relativity: that free particles follow geodesics. The new technologies to be demonstrated in a space environment include: inertial sensors, high precision laser interferometry to free floating mirrors, and micro-Newton proportional thrusters. LISA Pathfinder will be launched on a dedicated launch vehicle in late 2011 into a low Earth orbit. By a transfer trajectory, the sciencecraft will enter its final orbit around the first Sun-Earth Lagrange point. First science results are expected approximately 3 months thereafter. Here, we give an overview of the mission including the technologies being demonstrated.

Racca, Giuseppe D.; McNamara, Paul W.

2010-03-01

198

Melas Chasma: A Mars Pathfinder view of Valles Marineris  

NASA Technical Reports Server (NTRS)

A Mars Pathfinder landing site in Melas Chasma (Valles Marineris) would yield significant science return, but is outside present mission constraints. In Melas Chasma, Mars Pathfinder could investigate minimally altered basaltic material, sedimentary deposits, chemical weathering, tectonic features, the highland crust, equatorial weather, and Valles mists. Critical issues include the following: (1) nature and the origin of the Valles interior layered deposits, important for understanding water as a sedimentary and chemical agent, and for the past existence of of environments favorable for life; (2) compositions of little-altered basaltic sands, important for understanding magma genesis and weathering on Mars, and the martian meteorites; and (3) structure and composition of the highland crust, important for understanding Mars' early history .

Treiman, Allan H.; Murchie, Scott

1994-01-01

199

Java PathFinder: A Translator From Java to Promela  

NASA Technical Reports Server (NTRS)

JAVA PATHFINDER, JPF, is a prototype translator from JAVA to PROMELA, the modeling language of the SPIN model checker. JPF is a product of a major effort by the Automated Software Engineering group at NASA Ames to make model checking technology part of the software process. Experience has shown that severe bugs can be found in final code using this technique, and that automated translation from a programming language to a modeling language like PROMELA can help reducing the effort required.

Havelund, Klaus

1999-01-01

200

Java PathFinder http://cent.xii.jp/  

E-print Network

.foo() } t2 2 #4 #10 t1 #9 #10 #12;() synchronized (this) { other.foo() } 1 synchronized (this) { other #12;Java PathFinder (JPF) · ­ : Java ­ ­ Java Virtual Machine ­ ­ · ­ sourceforge.net ­ NASA Ames Research Center W.Visser ­ http://babelfish.arc.nasa.gov/trac/jpf/wiki 3 #12; · Java · · Java

Hagiya, Masami

201

Adaptive Avoidance of Reef Noise  

PubMed Central

Auditory information is widely used throughout the animal kingdom in both terrestrial and aquatic environments. Some marine species are dependent on reefs for adult survival and reproduction, and are known to use reef noise to guide orientation towards suitable habitat. Many others that forage in food-rich inshore waters would, however, benefit from avoiding the high density of predators resident on reefs, but nothing is known about whether acoustic cues are used in this context. By analysing a sample of nearly 700,000 crustaceans, caught during experimental playbacks in light traps in the Great Barrier Reef lagoon, we demonstrate an auditory capability in a broad suite of previously neglected taxa, and provide the first evidence in any marine organisms that reef noise can act as a deterrent. In contrast to the larvae of species that require reef habitat for future success, which showed an attraction to broadcasted reef noise, taxa with a pelagic or nocturnally emergent lifestyle actively avoided it. Our results suggest that a far greater range of invertebrate taxa than previously thought can respond to acoustic cues, emphasising yet further the potential negative impact of globally increasing levels of underwater anthropogenic noise. PMID:21326604

Simpson, Stephen D.; Radford, Andrew N.; Tickle, Edward J.; Meekan, Mark G.; Jeffs, Andrew G.

2011-01-01

202

Chryse Planitia as a Mars Pathfinder landing site: The imperative of building on previous ground truth  

NASA Technical Reports Server (NTRS)

Based on consideration of the geological characteristics of Chryse Planitia, the requirements for Mars Pathfinder landing sites, the nature of the mission, the scale of the observations to be made, and the need to build outward from previous experience, a new mission to Chryse Planitia offers several advantages that are difficult to ignore as well as offering a low-gamble/high-return mission scenario. Considering the need to ensure a successful mission, and to ensure the continued health of planetary exploration, the reasons for a new mission to Chryse Planitia are compelling. Results of 1:500,000 mapping, operational benefits of Chryse Planitia, science benefits of Chryse Planitia, and conclusions and site recommendations are discussed.

Crumpler, Larry S.

1994-01-01

203

LISA and LISA Pathfinder: Gravitational Wave Observation in Space  

NASA Technical Reports Server (NTRS)

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.

Guzman, Felipe

2010-01-01

204

Measuring coral reef community metabolism using new benthic chamber technology  

USGS Publications Warehouse

Accurate measurement of coral reef community metabolism is a necessity for process monitoring and in situ experimentation on coral reef health. Traditional methodologies used for these measurements are effective but limited by location and scale constraints. We present field trial results for a new benthic chamber system called the Submersible Habitat for Analyzing Reef Quality (SHARQ). This large, portable incubation system enables in situ measurement and experimentation on community- scale metabolism. Rates of photosynthesis, respiration, and calcification were measured using the SHARQ for a variety of coral reef substrate types on the reef flat of South Molokai, Hawaii, and in Biscayne National Park, Florida. Values for daily gross production, 24-h respiration, and net calcification ranged from 0.26 to 6.45 g O2 m-2 day-1, 1.96 to 8.10 g O2 m-2 24 h-1, and 0.02 to 2.0 g CaCO3 m -2 day-1, respectively, for all substrate types. Field trials indicate that the SHARQ incubation chamber is an effective tool for in situ isolation of a water mass over a variety of benthic substrate types for process monitoring, experimentation, and other applications.

Yates, K.K.; Halley, R.B.

2003-01-01

205

NOAA's hydrolab conducts reef studies  

NASA Astrophysics Data System (ADS)

This summer, scuba-diving scientists operating from Hydrolab, NOAA's undersea laboratory, are carrying out four experiments aimed at producing better management of coral reefs and their fishery resources. Hydrolab is located at a depth of 50 feet, near the mouth of the Salt River, off St. Croix, U.S. Virgin Islands. The lab houses four scientists for up to 2 weeks at a time, permitting them to swim out into the water to conduct research. The projects make use of both the natural coral reef near Hydrolab and the nearby artificial reef constructed for comparison studies.

206

SIMAC: development and implementation of a coral reef monitoring network in Colombia.  

PubMed

Significant coral reef decline has been observed in Colombia during the last three decades. However, due to the lack of monitoring activities, most of the information about health and changes was fragmentary or inadequate. To develop an expanded nation-wide reef-monitoring program, in 1998 INVEMAR (Instituto de Investigaciones Marinas y Costeras: "Colombian Institute of Marine and Coastal Research") designed and implemented SIMAC (Sistema Nacional de Monitorco de Arrecifes Coralinos en Colombia: "National Monitoring System of Coral Reefs in Colombia") with the participation of other institutions. By the end of 2003 the SIMAC network reached more than twice its initial size, covering ten reef areas (seven in the Caribbean and three in the Pacific), 63 reef sites and 263 permanent transects. SIMAC monitoring continued without interruption until 2008 and should persist in the long-term. The SIMAC has a large database and consists basically of water quality measurements (temperature, salinity, turbidity) and a yearly estimation of benthic reef cover, coral disease prevalence, gorgonian density, abundance of important mobile invertebrates, fish diversity and abundance of important fish species. A methods manual is available in the Internet. Data and results of SIMAC have been widely circulated through a summary report published annually since 2000 for the Colombian environmental agencies and the general public, as well as numerous national and international scientific papers and presentations at meetings. SIMAC information has contributed to support regional and global reef monitoring networks and databases (i.e. CARICOMP, GCRMN, ReefBase). PMID:20873041

Garzón-Ferreira, Jaime; Rodríguez-Ramírez, Alberto

2010-05-01

207

Home Reef, South Pacific  

NASA Technical Reports Server (NTRS)

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

2006-01-01

208

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....

209

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.

210

Ancient reef ecosystem expansion and collapse  

NASA Astrophysics Data System (ADS)

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 major periods of worldwide reef expansion (e.g. mid-Silurian-Late Devonian), corresponding to global warming well above present day norms, and periods of complete global reef collapse (e.g., mid-Cambrian to mid-Ordovician, Late Devonian) corresponding to global perturbations. At times of major reef expansion in the Paleozoic, areas covered by equatorial reef and inter-reef carbonate platforms are conservatively estimated to have periodically exceeded 5 million sq. km, nearly ten times that in the modern ocean. At times of global reef collapse, e.g. the Famennian (Late Devonian), reef complexes were completely absent or, at best, covered <1000 sq. km. The chief factors relating to periodic collapse and mass extinction of reef biotas appear to be related to climatic change and possibly ocean anoxic events, in turn as a response to large scale, geologically disruptive factors such as plate collisions, plate movement across equatorial belts and volcanism. Stress “signals” in Cambrian through Cretaceous reef ecosystems appear to be comparable to those of today: whether these relate to physical versus biological stress is uncertain. Reef stress is evident in globally reduced areas and thicknesses of reef carbonate production, the absence of large scale barrier reef systems and reduction to smaller patch reef complexes (or, periodically, following mass extinctions, no reefs at all), reduced species and genus diversity, small skeletons or colonies, limited or no biotic zonation along reef transects, and arrested succession and ecologic replacement of complex, more highly evolved taxa by “simpler”, stress-resistant disaster taxa at the genus to ordinal (or even phylum) level.

Copper, P.

1994-01-01

211

Microbiota of the major South atlantic reef building coral mussismilia.  

PubMed

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

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

212

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

Microsoft Academic Search

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)

A. L. Alldredge; J. M. King

1977-01-01

213

CoralReefs(1995)14:91-97 CoralReefs9 Springer-Verlag1995 ~  

E-print Network

CoralReefs(1995)14:91-97 CoralReefs9 Springer-Verlag1995 ~ Taphonomy of crown-of-thorns starfish; and two theme issues of Coral Reefs in vols 9 (1990) and 11 Correspondenceto:B.J. Greentein (1992 sedimentologicanaly- sis of reef sediments provides conclusive evidence that the two damaging outbreaks in the last 35

Greenstein, Benjamin J.

214

112 National Coral Reef Action Strategy CORAL REEF CONSERVATION ACT OF 2000  

E-print Network

Reef Action Strategy APPENDIX A CORAL REEF CONSERVATION ACT OF 2000 [P.L. 106-562; 16 U.S.C. 6401 et seq; December 23, 2000] TITLE II--CORAL REEF CONSERVATION SEC. 201. SHORT TITLE. This title may be cited as the `Coral Reef Conservation Act of 2000'. SEC. 202. PURPOSES. The purposes of this title are

215

ORIGINAL ARTICLE Black reefs: iron-induced phase shifts on coral reefs  

E-print Network

ORIGINAL ARTICLE Black reefs: iron-induced phase shifts on coral reefs This article has been, Australia The Line Islands are calcium carbonate coral reef platforms located in iron-poor regions surveys show that the live coral cover was reduced from 40 to 60% to o10% on black reefs on Millennium

Smith, Jennifer E.

216

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.

217

Coral reef crisis in deep and shallow reefs: 30 years of constancy and change in reefs of Curacao and Bonaire  

Microsoft Academic Search

Coral reefs are thought to be in worldwide decline but available data are practically limited to reefs shallower than 25 m.\\u000a Zooxanthellate coral communities in deep reefs (30–40 m) are relatively unstudied. Our question is: what is happening in deep\\u000a reefs in terms of coral cover and coral mortality? We compare changes in species composition, coral mortality, and coral cover\\u000a at Caribbean

Rolf P. M. Bak; Gerard Nieuwland; Erik H. Meesters

2005-01-01

218

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

E-print Network

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

LuÂ?trek, Mitja

219

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

E-print Network

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

LuÂ?trek, Mitja

220

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

E-print Network

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

LuÂ?trek, Mitja

221

Lookahead Pathology in Real-Time Path-Finding Vadim Bulitko  

E-print Network

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

LuÂ?trek, Mitja

222

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

E-print Network

The Tangible Pathfinder Design of a Wayfinding Trainer for the Visually Impaired Ehud Sharlin1 for an orientation and mobility (or wayfinding) trainer for the visually impaired--the Tangible Pathfinder, would have an important role in future HCI paradigm for the visually impaired. For example, young

Sharlin, Ehud

223

Reduction and Analysis of Meteorology Data from the Mars Pathfinder Lander  

NASA Technical Reports Server (NTRS)

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.

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

1998-01-01

224

CloudSat Project A NASA Earth System Science Pathfinder Mission  

E-print Network

............................................................................................................ 6 a. Hierarchical Data Processing Overview b. 1A-AUX (Level 1 Auxiliary Data mapped to CloudCloudSat Project A NASA Earth System Science Pathfinder Mission CloudSat Standard Data Products..................................................................................................18 2 #12;1. CloudSat Mission Overview CloudSat is a NASA Earth Sciences Systems Pathfinder (ESSP

Collett Jr., Jeffrey L.

225

Laser Interferometry for Gravitational Wave Observation: LISA and LISA Pathfinder  

NASA Technical Reports Server (NTRS)

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

Guzman, Felipe

2010-01-01

226

Neural pathfinding on uni- and multidirectional photopolymerized micropatterns.  

PubMed

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

Tuft, Bradley W; Xu, Linjing; White, Scott P; Seline, Alison E; Erwood, Andrew M; Hansen, Marlan R; Guymon, C Allan

2014-07-23

227

Glia, neurons, and axon pathfinding during optic chiasm development.  

PubMed

The importance of vision in the behavior of animals, from invertebrates to primates, has led to a good deal of interest in how projection neurons in the retina make specific connections with targets in the brain. Recent research has focused on the cellular interactions occurring between retinal ganglion cell (RGC) axons and specific glial and neuronal populations in the embryonic brain during formation of the mouse optic chiasm. These interactions appear to be involved both in determining the position of the optic chiasm on the ventral diencephalon (presumptive hypothalamus) and in ipsilateral and contralateral RGC axon pathfinding, development events fundamental to binocular vision in the adult animal. PMID:9384544

Mason, C A; Sretavan, D W

1997-10-01

228

Symbolic PathFinder: Symbolic Execution of Java Bytecode  

NASA Technical Reports Server (NTRS)

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.

Pasareanu, Corina S.; Rungta, Neha

2010-01-01

229

Rock and Soil Types at Pathfinder Landing Site  

NASA Technical Reports Server (NTRS)

Type areas of rocks and soils. (A) Dark rock type and bright soil type: Shown is the dark rock Barnacle Bill. Reflectance spectra typical of fresh basalt and APXS spectra indicating more silica-rich basaltic andesite compositions characterize this type. These rocks are typically the small boulders and intermediate-sized cobbles at the Pathfinder site. The bright soil type is very common and in this case comprises Barnacle Bill's wind tail and much of the surround soil area. This soil has a high reflectance and a strongly reddened spectrum indicative of oxidized ferric minerals. (B) Bright rock type: Shown is the bright rock Wedge. Reflectance spectra typical of weathered basalt and APXS spectra indicating basaltic compositions characterize this type. These rocks are typically larger than 1 meter in diameter and many display morphologies indicating flood deposition. (C) Pink rock type: Shown is the pink rock Scooby Doo. APXS and reflectance spectra indicate a composition and optical characteristics similar to the drift soil. However, the morphology of the pink rock type indicates a cemented or rocklike structure. This material may be a chemically cemented hardpan that underlies much of the Pathfinder site. (D) Dark soil type: The dark soil type is typically found on the windward sides of rocks or in rock-free areas like Photometry Flats (shown here) where the bright soil has been striped away by aeolian action or in open areas. Other locations include the Mermaid Dune. (E) Disturbed soil type: The darkening of disturbed soil relative to its parent material, bright soil, as a result of changes in soil texture and compaction caused by movement of the rover and retraction of the lander airbag. (F) Lamb-like soil type: This soil type shows reflectance and spectral characteristics intermediate between the bright and dark soils. Its distinguishing feature is a weak spectral absorption near 900 nanometers not seen in either the bright or dark soils.

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).

1997-01-01

230

The LISA PathFinder DMU Software, a Global Overview  

NASA Astrophysics Data System (ADS)

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.

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

2013-01-01

231

Ocean acidification worse in coral reefs  

NASA Astrophysics Data System (ADS)

The rate of ocean acidification in coral reefs outpaces the rise in carbon dioxide (CO2) in Earth's atmosphere, indicating that anthropogenic carbon emissions alone are not to blame for the threat to coral reefs, a new study shows.

Betz, Eric O.

2014-12-01

232

Call to protect all coral reefs  

NASA Astrophysics Data System (ADS)

The world's coral reefs are in decline, threatening the food security of millions of people. Adopting an ecosystem-scale approach that protects deep as well as shallow reefs would deliver several social and economic benefits.

Bridge, Tom C. L.; Hughes, Terry P.; Guinotte, John M.; Bongaerts, Pim

2013-06-01

233

Long Wave Breaking Effects on Fringing Reefs  

E-print Network

Modeling of wave energy transformation and breaking on fringing reefs is inherently difficult due to the unique topography of reefs. Prior methods of determining dissipation are based on empirical data from gently sloping beaches and offer only bulk...

Goertz, John 1985-

2012-12-12

234

The dynamics of benthic microbial communities at Davies Reef, central Great Barrier Reef  

Microsoft Academic Search

The dynamics of benthic microbial communities were examined within different functional zones (reef crest, reef flat, lagoon) of Davies Reef, central Great Barrier Reef, in winter. Bacterial numbers did not change significantly across the reef with a mean abundance \\u000a$$(\\\\bar x{\\\\text{ }} \\\\pm {\\\\text{ 1 SE)}}$$\\u000a of 1.3 (±0.6) x 109 cells g-1 DW of sediment. Bacterial production, measured as

L. A. Hansen; D. M. Alongi; D. J. W. Moriarty; P. C. Pollard

1987-01-01

235

Trapping and dispersion of coral eggs around Bowden Reef, Great Barrier Reef, following mass coral spawning  

Microsoft Academic Search

Bowden Reef is a 5 km long kidney-shaped coral reef with a lagoon, located on the mid-shelf of the central region of the Great Barrier Reef. Field studies were carried out, in November 1986, at the time of mass coral spawning, of the water circulation around Bowden Reef and in the surrounding inter-reefal waters. The near-reef water circulation was strongly

Eric Wolanski; Derek Burrage; Brian King

1989-01-01

236

Coral communities and reef growth in the southern Great Barrier Reef  

Microsoft Academic Search

.  ?Fringing reef development is limited around 22°?S along the inner Great Barrier Reef, although there is substantial development\\u000a north and south of this latitude. This study examined the relationships among coral communities and the extent of reef development.\\u000a Reefs were examined to determine coral composition, colony abundance, colony size and growth form between the latitudes 20°S\\u000a and 23°S. Major reef

R. van Woesik; T. J. Done

1997-01-01

237

Wave Processes on Coral Reef Flats: Implications for Reef Geomorphology Using Australian Case Studies  

Microsoft Academic Search

KENCH, P.S., and BRANDER, R.W., 2006. Wave processes on coral reef flats: implications for reef geomorphology using Australian case studies. Journal of Coastal Research, 22(1), 209-223. West Palm Beach (Florida), ISSN 0749- 0208. Australian reef flats on the Cocos (Keeling) Islands atoll, Indian Ocean; Warraber Reef, Torres Strait; and Lady Elliot Island, Great Barrier Reef vary greatly in morphology (width,

Paul S. Kench; Robert W. Brander

2006-01-01

238

Coral Reef Conservation: A Reef of Your Own  

NSDL National Science Digital Library

This web-based lesson focuses on the physiological, ecological, and behavioral strategies that contribute to the success of reef-building corals. Students will learn to describe and explain the importance of asexual and sexual reproductive strategies to reef-building corals, why it is important that the corals have a nutritional strategy that includes both photosynthesis and carnivory, two behaviors that they use to compete for living space with other species, and how coral reefs can produce high levels of biological material when the waters surround­ing them contain relatively small amounts of the nutri­ents normally needed to support biological production. Links to the required online resources are provided.

2011-08-23

239

Miocene reefs of Dominican Republic  

SciTech Connect

The reefs are overlain by conglomeratic strata. The stratigraphic setting of these reefs suggests that they have developed along the stalled portions of rapidly prograding fan deltas. Thickets and layers of coral debris are found seaward and stratigraphically above the well-developed reef. The matrix sediments are exclusively fine-grained sand to mud, and the fauna are suggestive of more open shelf conditions. In thickets, branched (porites spp., Pocillopora spp.), small massive (Montastrea spp., Siderastrea spp.), and foliose or plate like (Agaricia spp.) corals are found upright in the muddy sediment. Similarities in coral species and areal proximity suggest that thickets are the source of most layers of coralline debris. The association of coral debris with graded bedding and cross-bedding suggests that coral debris has been reworked by storms. The growth of corals and development of coral reefs in the Miocene-Pliocene Yaque Group is limited only by opportunities created by the slowing of siliciclastic sedimentation. Soft, muddy, terrigenous substrates and a continuing supply of terrigenous mud exert only a limited, indirect effect on reef growth.

Evans, C.C.

1988-01-01

240

Coal waste artificial reef program. Phase I  

Microsoft Academic Search

The overall objective of the Coal Waste Artificial Reef Program is to explore the feasibility of a method for ocean disposal of fly ash and scrubber sludge from coal-fired power plants. The program is to construct an artificial reef in the Atlantic Ocean near Long Island from stabilized blocks of these waste materials. The reef is expected to enhance biological

P. M. J. Woodhead; I. W. Duedall; N. F. Lansing

1979-01-01

241

Coral Reefs and Their Management in Tanzania  

Microsoft Academic Search

Coral reefs are very important in Tanzania, both ecologically and socio-economically, as major fishing grounds and tourist attractions. Numerous fringing and patch reefs are located along about two-thirds of Tanzania's coastline. These reefs have been partially to severely degraded by human (primarily destructive fishing practices) and natural (particularly coral bleaching) causes. These immediate human causes have been brought about by

Greg M. Wagner

242

Experimental biology of coral reef ecosystems  

Microsoft Academic Search

Coral reef ecosystems are at the crossroads. While significant gaps still exist in our understanding of how “normal” reefs work, unprecedented changes in coral reef systems have forced the research community to change its focus from basic research to understand how one of the most diverse ecosystems in the world works to basic research with strong applied implications to alleviate

Michael P. Lesser

2004-01-01

243

Assessing Coral Reef Condition: Eliciting Community Meanings  

Microsoft Academic Search

Photographs depicting a gradient of coral reef condition associated with anchor damage were assessed and described by 76 research participants. The participants were divided into two groups: those with and those without occupational experience of coral reefs. Three important meanings ascribed to coral reefs were elicited. The most important meaning was “evaluation,” whether the scenes were perceived positively or negatively.

Elizabeth A. Dinsdale; D. Mark Fenton

2006-01-01

244

The future of coral reefs Nancy Knowlton*  

E-print Network

Colloquium The future of coral reefs Nancy Knowlton* Marine Biology Research Division 0202, Scripps Tropical Research Institute, Apartado 2072, Balboa, Republic of Panama Coral reefs, with their millions communities, and coral death. (iv) The activities of people near reefs increase both fishing pressure

Bermingham, Eldredge

245

Development and implementation of coral reef biocriteria in U.S. jurisdictions.  

PubMed

Coral reefs worldwide are declining at an alarming rate and are under continuous threat from both natural and anthropogenic environmental stressors. Warmer sea temperatures attributed to global climate change and numerous human activities at local scales place these valuable ecosystems at risk. Reefs provide numerous services, including shoreline protection, fishing, tourism and biological diversity, which are lost through physical damage, overfishing, and pollution. Pollution can be controlled under provisions of the Clean Water Act, but these options have not been fully employed to protect coral reefs. No U.S. jurisdiction has implemented coral reef biocriteria, which are narrative or quantitative water quality standards based on the condition of a biological resource or assemblage. The President's Ocean Action Plan directs the U.S. Environmental Protection Agency (EPA) to develop biological assessment methods and biological criteria for evaluating and maintaining the health of coral reef ecosystems. EPA has formed the Coral Reef Biocriteria Working Group (CRBWG) to foster development of coral reef biocriteria through focused research, evaluation and communication among Agency partners and U.S. jurisdictions. Ongoing CRBWG activities include development and evaluation of a rapid bioassessment protocol for application in biocriteria programs; development of a survey design and monitoring strategy for the U.S. Virgin Islands; comprehensive reviews of biocriteria approaches proposed by states and territories; and assembly of data from a variety of monitoring programs for additional metrics. Guidance documents are being prepared to assist U.S. jurisdictions in reaching protective and defensible biocriteria. PMID:19052888

Bradley, Patricia; Fisher, William S; Bell, Heidi; Davis, Wayne; Chan, Valerie; LoBue, Charles; Wiltse, Wendy

2009-03-01

246

Sedimentary Geochemistry of Martian Samples from the Pathfinder Mission  

NASA Technical Reports Server (NTRS)

The purpose of this research project was to evaluate the APXS data collected on soils and rocks at the Pathfinder site in terms of sedimentary geochemistry. Below are described the major findings of this research: (1) An influential model to explain the chemical variation among Pathfinder soils and rocks is a two component mixing model where rocks of fairly uniform composition mix with soil of uniform composition; (2) The very strong positive correlation between MgO and SO, points to a control by a MgSO4 mineral however, spectroscopic data continue to suggest that Fe-sulfates, notably schwertmannite and jarosite, may be important components; (3) In an attempt to better understand the causes of complexities in mixing relationships, the possible influence of sedimentary transport has been evaluated; (4) Another aspect of this research has been to examine the possibility of sedimentary silica being a significant phase on Mars; and (5) On Earth, the geochemistry of sedimentary rocks has been used to constrain the chemical composition of the continental crust and an important part of this research was to evaluate this approach for Mars.

McLennan, Scott M.

2001-01-01

247

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

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

248

LISA Pathfinder: hardware tests and their input to the mission  

NASA Astrophysics Data System (ADS)

The Laser Interferometer Space Antenna (LISA) is a joint ESA-NASA mission for the first space-borne gravitational wave detector. LISA aims to detect sources in the 0.1mHz to 1Hz range, which include supermassive black holes and galactic binary stars. Core technologies required for the LISA mission, including drag-free test mass control, picometre interferometry and micro-Newton thrusters, cannot be tested on-ground. Therefore, a precursor satellite, LISA Pathfinder, has been developed as a technology demonstration mission. The preparations for the LISA Pathfinder mission have reached an exciting stage. Tests of the engineering model of the optical metrology system have recently been completed at the Albert Einstein Institute, Hannover, and flight model tests are now underway. Significantly, they represent the first complete integration and testing of the space-qualified hardware and are the first tests on system level. The results and test procedures of these campaigns will be utilised directly in the ground-based flight hardware tests, and subsequently within in-flight operations. In addition, they allow valuable testing of the data analysis methods using the MatLab based LTP data analysis toolbox. This contribution presents an overview of the test campaigns calibration, control and perfor-mance results, focusing on the implications for the Experimental Master Plan which provides the basis for the in-flight operations and procedures.

Audley, Heather

249

Career pathfinders: a qualitative study of career development.  

PubMed

This paper examined the perceptions of career path and issues of MBA students in response to Lore's The Pathfinder, a comprehensive career-planning model. Using internet discussion boards, an interactive dialogue was mentioned by participants in response to the components of Lore's model. The sample consisted of 50 fully employed MBA students enrolled in a course on self-assessment and career planning. A total of 1,781 separate postings were made and analyzed, using inductive analysis derived from discussion threads based on Lore's categories: comments on Lore's Pathfinder model, living a life you love (what's the holdup, career fantasies, work and family issues, and career selection), how to get there from here (commitment and future from the present), and designing your future career. Findings indicated several interesting trends in the career planning of current MBA students, particularly the importance of self or self-reflective observations in real time as students who are also fully employed formulate career plans. Implications for psychologists and career counselors, career development models, and suggestions for research are presented. PMID:16796109

Beutell, Icholas J; O'Hare, Marianne M

2006-04-01

250

Construction and testing of the optical bench for LISA Pathfinder  

NASA Astrophysics Data System (ADS)

eLISA is a space mission designed to measure gravitational radiation over a frequency range of 0.1-100?mHz (European Space Agency LISA Assessment Study Report 2011). It uses laser interferometry to measure changes of order 10\\,pm /\\sqrt{Hz} in the separation of inertial test masses housed in spacecraft separated by 1 million km. LISA Pathfinder (LPF) is a technology demonstrator mission that will test the key eLISA technologies of inertial test masses monitored by laser interferometry in a drag-free spacecraft. The optical bench that provides the interferometry for LPF must meet a number of stringent requirements: the optical path must be stable at the few pm /\\sqrt{Hz} level; it must direct the optical beams onto the inertial masses with an accuracy of better than ±25??m, and it must be robust enough not only to survive launch vibrations but to achieve full performance after launch. In this paper we describe the construction and testing of the flight optical bench for LISA Pathfinder that meets all the design requirements.

Robertson, D. I.; Fitzsimons, E. D.; Killow, C. J.; Perreur-Lloyd, M.; Ward, H.; Bryant, J.; Cruise, A. M.; Dixon, G.; Hoyland, D.; Smith, D.; Bogenstahl, J.

2013-04-01

251

Pathfinder aircraft liftoff on altitude record setting flight of 71,500 feet  

NASA Technical Reports Server (NTRS)

The Pathfinder aircraft has set a new unofficial world record for high-altitude flight of over 71,500 feet for solar-powered aircraft at the U.S. Navy's Pacific Missile Range Facility, Kauai, Hawaii. Pathfinder was designed and manufactured by AeroVironment, Inc, of Simi Valley, California, and was operated by the firm under a jointly sponsored research agreement with NASA's Dryden Flight Research Center, Edwards, California. Pathfinder's record-breaking flight occurred July 7, 1997. The aircraft took off at 11:34 a.m. PDT, passed its previous record altitude of 67,350 feet at about 5:45 p.m. and then reached its new record altitude at 7 p.m. The mission ended with a perfect nighttime landing at 2:05 a.m. PDT July 8. The new record is the highest altitude ever attained by a propellor-driven aircraft. Before Pathfinder, the altitude record for propellor-driven aircraft was 67,028 feet, set by the experimental Boeing Condor remotely piloted aircraft. 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.)

1997-01-01

252

Coral reef crisis in deep and shallow reefs: 30 years of constancy and change in reefs of Curacao and Bonaire  

NASA Astrophysics Data System (ADS)

Coral reefs are thought to be in worldwide decline but available data are practically limited to reefs shallower than 25 m. Zooxanthellate coral communities in deep reefs (30-40 m) are relatively unstudied. Our question is: what is happening in deep reefs in terms of coral cover and coral mortality? We compare changes in species composition, coral mortality, and coral cover at Caribbean (Curacao and Bonaire) deep (30-40 m) and shallow reefs (10-20 m) using long-term (1973-2002) data from permanent photo quadrats. About 20 zooxanthellate coral species are common in the deep-reef communities, dominated by Agaricia sp., with coral cover up to 60%. In contrast with shallow reefs, there is no decrease in coral cover or number of coral colonies in deep reefs over the last 30 years. In deep reefs, non-agaricid species are decreasing but agaricid domination will be interrupted by natural catastrophic mortality such as deep coral bleaching and storms. Temperature is a vastly fluctuating variable in the deep-reef environment with extremely low temperatures possibly related to deep-reef bleaching.

Bak, Rolf P. M.; Nieuwland, Gerard; Meesters, Erik H.

2005-11-01

253

Private development of artificial reefs  

E-print Network

this development scheme an entrepreneur would have the exclusive right to fish in the waters surrounding an artificial reef and would charge fishermen for the use of the reef. The concerns of a potential investor addressed by this thesis are (1) the effects... have limited funds T e re erences in this thesis follow the style of the Coastal Zone Mana ement Journal. for such projects, and lack the profit incentive which mo- tivates suppliers to meet demands for their resources. It can also be argued...

Burns, Arthur Allen

1978-01-01

254

Coral skeletons provide historical evidence of phosphorus runoff on the great barrier reef.  

PubMed

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

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

2013-01-01

255

The future of coral reefs  

PubMed Central

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. PMID:11344288

Knowlton, Nancy

2001-01-01

256

Quantifying Coral Reef Ecosystem Services  

EPA Science Inventory

Coral reefs have been declining during the last four decades as a result of both local and global anthropogenic stresses. Numerous research efforts to elucidate the nature, causes, magnitude, and potential remedies for the decline have led to the widely held belief that the recov...

257

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...

258

The future of coral reefs.  

PubMed

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 degrees 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. PMID:11344288

Knowlton, N

2001-05-01

259

The future of coral reefs  

NASA Astrophysics Data System (ADS)

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.

Knowlton, Nancy

2001-05-01

260

Sublittoral Reef Phenomena of Aldabra  

Microsoft Academic Search

DURING phase 6 of the Royal Society expedition to Aldabra the sublittoral structure of the reef front was studied by means of one detailed reference transect (marked 1 in Fig. 1) and thirteen survey transects. All were levelled by SCUBA divers in the following way. Two divers holding the ends of a 10 m tape ``leapfrogged'' over each other in

J. Barnes; D. J. Bellamy; D. J. Jones; B. A. Whitton

1970-01-01

261

State space modelling and data analysis exercises in LISA Pathfinder  

E-print Network

LISA Pathfinder is a mission planned by the European Space Agency 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 functionalities 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.

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

2013-06-21

262

State Space Modelling and Data Analysis Exercises in LISA Pathfinder  

NASA Astrophysics Data System (ADS)

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.

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

263

Mars Pathfinder Near-Field Rock Distribution Re-Evaluation  

NASA Technical Reports Server (NTRS)

We have completed analysis of a new near-field rock count at the Mars Pathfinder landing site and determined that the previously published rock count suggesting 16% cumulative fractional area (CFA) covered by rocks is incorrect. The earlier value is not so much wrong (our new CFA is 20%), as right for the wrong reason: both the old and the new CFA's are consistent with remote sensing data, however the earlier determination incorrectly calculated rock coverage using apparent width rather than average diameter. Here we present details of the new rock database and the new statistics, as well as the importance of using rock average diameter for rock population statistics. The changes to the near-field data do not affect the far-field rock statistics.

Haldemann, A. F. C.; Golombek, M. P.

2003-01-01

264

Wheel Abrasion Experiment Metals Selection for Mars Pathfinder Mission  

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

265

Drill/borescope System for the Mars Polar Pathfinder  

NASA Technical Reports Server (NTRS)

The primary goals of the Mars Polar Pathfinder (MPP) Discovery Mission are to characterize the composition and structure of Mars' north polar ice cap, and to determine whether a climate record may be preserved in layers of ice and dust. The MPP would land as close as possible to the geographic north pole of Mars and use a set of instruments similar to those used by glaciologists to study polar ice caps on Earth: a radar sounder, a drill/borescope system, and a thermal probe. The drill/borescope system will drill approximately 50 cm into the surface and image the sides of the hole at 10 micron resolution for compositional and stratigraphic analysis. Several uncertainties have guided the development of this instrument, and they are discussed.

Paige, D. A.; Wood, S. E.; Vasavada, A. R.

1993-01-01

266

Prediction and Validation of Mars Pathfinder Hypersonic Aerodynamic Data Base  

NASA Technical Reports Server (NTRS)

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.

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

1998-01-01

267

The LISA Pathfinder interferometry—hardware and system testing  

NASA Astrophysics Data System (ADS)

Preparations for the LISA Pathfinder mission have reached an exciting stage. Tests of the engineering model (EM) of the optical metrology system have recently been completed at the Albert Einstein Institute, Hannover, and flight model tests are now underway. Significantly, they represent the first complete integration and testing of the space-qualified hardware and are the first tests on an optical system level. The results and test procedures of these campaigns will be utilized directly in the ground-based flight hardware tests, and subsequently during in-flight operations. In addition, they allow valuable testing of the data analysis methods using the MATLAB-based LTP data analysis toolbox. This paper presents an overview of the results from the EM test campaign that was successfully completed in December 2009.

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

2011-05-01

268

Preliminary Results from the Mars Pathfinder ASI/MET Experiment  

NASA Technical Reports Server (NTRS)

Mars Pathfinder successfully landed in the Ares Vallis flood plain (19.3 N, 33.6 W) on July 4, 1997. The spacecraft carried a suite of instruments to record the structure of the atmosphere during the entry, descent, and landing as well as for monitoring meteorological phenomenon while on the surface. Collectively, these instruments are known as the ASI/MET experiment (Atmospheric Structure Investigation/Meteorology). In this paper we present preliminary results from the ASI/MET experiment. As of this writing, the spacecraft is healthy and continues to take daily meteorological measurements. We expect this will continue for almost one more earth year. Additional information is contained in the original extended abstract.

Haberle, R. M.; Schofield, J. T.; Crisp, D.; Barnes, J. R.; Magalhaes, J. A.; Murphy, J. R.; Seiff, A.; Wilson, G.; Larsen, S.; Young, Richard E. (Technical Monitor)

1997-01-01

269

Aeolin Features and Processes at the Mars Pathfinder Landing Site  

NASA Technical Reports Server (NTRS)

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 consistant with formation involving sand-size particles. Although some features, such as dunes, could develop from saltating sand-size aggregates of finer grains, the discovery of ventifact flutes cut in rocks strongly suggests that at least some of the grains are crystalline, rather than aggregates. Excluding the ventifacts, the orientations of the wind-related features correlate well with the orientations of bright wind steaks seen on Viking Orbiter images in the general area. They also correlate with wind direction predictions from the NASA-Ames General Circulation Model (GCM) which show that the strongest winds in the area occur in the northern hemisphere winter and are directed toward 209 degrees.

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

1999-01-01

270

Mars Pathfinder and the exploration of southern Amazonis Planitia  

NASA Technical Reports Server (NTRS)

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.

Barlow, Nadine G.

1994-01-01

271

Effects of island mass: Water flow and plankton pattern around a reef in the Great Barrier Reef lagoon, Australia  

Microsoft Academic Search

Water currents and zooplankton distributions are described for Pandora Reef, a coralline platform reef topped by a small sand spit, subject to tidal currents within the Great Barrier Reef lagoon (Queensland, Australia). Oncoming tidal currents separated 500 m upstream of the l-km oblong reef. Zooplankton accumulated around the reef variously according to taxo- nomic group. Copepods and chaetognaths were most

W. M. HAMNER; I. R. HAURI

1981-01-01

272

Coral Reefs (2005) 24: 593 DOI 10.1007/s00338-005-0043-zReef sites  

E-print Network

Coral Reefs (2005) 24: 593 DOI 10.1007/s00338-005-0043-zReef sites Fig. 2 Fossil coral reef in southern Exmouth Gulf, Western Australia. The fossil coral reef is exposed at Point Maxwell et al. (1998) and White et al. (1998). U-series dates obtained from reef corals preserved

Greenstein, Benjamin J.

273

Land-based nutrient enrichment of the Buccoo Reef Complex and fringing coral reefs of Tobago, West Indies  

E-print Network

Land-based nutrient enrichment of the Buccoo Reef Complex and fringing coral reefs of Tobago, West 33701, USA a r t i c l e i n f o Keywords: Coral reef Macroalgae Eutrophication Sewage Nitrogen of Tobago's coral reefs. Ã? 2009 Elsevier Ltd. All rights reserved. 1. Introduction Coral reefs

Meyers, Steven D.

274

Battelle developing reefs to ease habitat losses  

SciTech Connect

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.

Not Available

1993-04-01

275

PATHFINDER REVIEW COMMITTEE FINAL REPORT Presented to UC Berkeley Library Cabinet  

E-print Network

Pathfinder Features D. Position Paper from Library Sciences Council E. The UC Davis experience: statement with members of the Arts and Humanities and the Social Sciences councils. The Library Sciences Council provided

California at Berkeley, University of

276

Gambling on the Protestants: the Pathfinder Fund and birth control in Peru, 1958-1965.  

PubMed

Among the agencies involved in population control activities in the mid-twentieth century, none scored as many early victories in Latin America as did the Pathfinder Fund, founded by Procter & Gamble scion Clarence Gamble. This article analyzes a style in the delivery of family planning assistance in the developing world through the work of the Pathfinder Fund in Peru, the organization's hub in South America, and shows how Pathfinder personnel collaborated with local Protestant institutions. Its Protestant allies helped Pathfinder set up and manage rapid interventions such as the production of pamphlets, the smuggling of contraceptives, and the enrollment of physicians as advocates of the use of intrauterine devices. Although these rapid interventions helped quickly disseminate information and certain technologies among a fortunate few, they also weakened legitimate state agencies, neglected the monitoring of the safety of the drugs supplied, and alienated allies with their high-handed boldness. PMID:24976165

López, L Necochea

2014-01-01

277

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

NASA Technical Reports Server (NTRS)

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.

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

278

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

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

279

Pathfinder aircraft prepared for flight showing solar cell arrays on wing  

NASA Technical Reports Server (NTRS)

The solar cell arrays, which cover about 75 percent of its upper wing surface, are clearly evident in this view of the Pathfinder solar-electric aircraft. The solar arrays are capable not only of absorbing direct sunlight, but can also absorb light reflected from the ground through the transparent lower surface of the 98-foot-long wing. Engineers and technicians from Pathfinder's developer, AeroVironment, Inc., conducted a successful two-hour check-out flight from NASA's Dryden Flight Research Center, Edwards, California, on Nov. 19, 1996. The craft then underwent preperations at AeroVironment's Simi Valley, California, facility for a new series of flight tests in Hawaii, during summer, 1997. 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.)

1996-01-01

280

The Pathfinder AVHRR land data set: An improved coarse resolution data set for terrestrial monitoring  

Microsoft Academic Search

A reprocessing of 12 years of global data from the Advanced Very High Resolution Radiometers on board the afternoon-viewing NOAA series satellites (NOAA-7, 9, and 11) is taking place as part of the NASA\\/NOAA Pathfinder project. A Pathfinder AVHRR land data set is being produced which is composed of global, 8 km NDVI with associated reflectances, brightness temperatures, solar and

M. E. JAMES; S. N. V. KALLURI

1994-01-01

281

Fringing and Nearshore Coral Reefs of the Great Barrier Reef: Episodic Holocene Development and Future Prospects  

Microsoft Academic Search

SMITHERS, S.G.; HOPLEY, D., and PARNELL, K.E., 2006. Fringing and nearshore coral reefs of the Great Barrier Reef: episodic Holocene development and future prospects. Journal of Coastal Research, 22(1), 175-187. West Palm Beach (Florida), ISSN 0749-0208. The Holocene growth of fringing and nearshore reefs on the GBR is examined. A review of data from 21 reefs indicates that most grow

S. G. Smithers; D. Hopley; K. E. Parnell

2006-01-01

282

Sedimentation on three caribbean atolls: Glovers reef, lighthouse reef and turneffe Islands, belize  

Microsoft Academic Search

Summary  The chief mode of carbonate sedimentation on the Belizean atolls Glovers Reef, Lighthouse Reef and Turneffe Islands is the\\u000a accumulation of organically-derived particles. Variations in the distribution of the composition and grain-sizes of surface\\u000a sediments, collected along transects across the atolls, are environmentally controlled. Two major sediment types may be distinguished.\\u000a (1) Reef and fore reef sediments are dominated by

Eberhard Gischler

1994-01-01

283

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

PubMed

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

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

2015-01-01

284

Astronaut Photography of Coral Reefs  

NASA Technical Reports Server (NTRS)

Astronaut photographs of tropical coastal areas may contain information on submerged features, including coral reefs, up to depths of about 15 m in clear waters. Previous research efforts have shown that astronaut photographs can aid in estimating coral reef locations and extent on national, regional and global scales, and allow characterization of major geomorphological rim and lagoon features (Andrefouet et al. 2000, in preparation). They can be combined with traditional satellite data to help distinguish between clouds and lagoon features such as pinnacles (Andrefouet and Robinson, in review). Furthermore, astronaut photographs may provide reef scientists and managers with information on the location and extent of river plumes and sediment run off, or facilitate identification of land cover types, including mangroves (Webb et al., in press). Photographs included in the section were selected based on several criteria. The primary consideration of the editors was that the photographs represent a worldwide distribution of coral reefs, have extremely low visual interference by cloud cover, and display a spatial scale reasonable for examining reef-related features. Once photographs were selected, they were digitized from 2nd generation copies. The color and contrast were hand corrected to an approximation of natural color (required to account for spectral differences between photographs due to the color sensitivities of films used, and differences in sun angle and exposure of the photographs). None of the photographs shown here have been georeferenced to correct them to a map projection and scale. Any distortions in features due to slightly oblique look angles when the photographs were taken through spacecraft windows remain. When feasible, near vertical photographs have been rotated so that north is toward the top. An approximate scale bar and north arrow have added using distinctive features on each photograph with reference to a 1:1,000,000 scale navigation chart. Astronaut photographs provide a unique source of moderate resolution reef remote sensing data because of their global coverage and (immediate) availability in the public domain. The database of photographs can be searched an browsed online and high-resolution digital copies of photographs in this atlas can be accessed via the Website of Earth Science and Image Analysis at NASA's Johnson Space Center:

Robinson, Julie A.; Noordeloos, Marco

2001-01-01

285

Evaluating coral reef health in American Samoa  

USGS Publications Warehouse

The study of coral disease has suffered from an absence of systematic approaches that are commonly used to determine causes of diseases in animals. There is a critical need to develop a standardized and portable nomenclature for coral lesions in the field and to incorporate more commonly available biomedical tools in coral disease surveys to determine the potential causes of lesions in corals. We characterized lesions in corals from American Samoa based on gross and microscopic morphology and classified them as discoloration, growth anomalies, or tissue loss. The most common microscopic finding in corals manifesting discoloration was the depletion of zooxanthellae, followed by necrosis, sometimes associated with invasive algae or fungi. The most common microscopic lesion in corals manifesting tissue loss was cell necrosis often associated with algae, fungi, or protozoa. Corals with growth anomaly had microscopic evidence of hyperplasia of gastrovascular canals, followed by necrosis associated with algae or metazoa (polychaete worms). Several species of apparently normal corals also had microscopic changes, including the presence of bacterial aggregates or crustacea in tissues. A single type of gross lesion (e.g., discoloration) could have different microscopic manifestations. This phenomenon underlines the importance of using microscopy to provide a more systematic description of coral lesions and to detect potential pathogens associated with these lesions.

Work, T.M.; Rameyer, R.A.

2005-01-01

286

Climate Change and Its Effect on Coral Reefs  

NASA Astrophysics Data System (ADS)

The viability of coral reefs has been linked to the extent to which the overlying sea water is supersaturated with respect to calcium carbonate, which in turn depends on the concentration of dissolved carbon dioxide. Projections of a future increase in carbon dioxide emissions indicate that the health of coral reefs may be seriously endangered, and trends in this direction already have been observed. The equilibria involved in this chemical system demonstrate several important concepts in elementary physical chemistry: Henry's law of gas solubility, solubility products of solids, and acid-base equilibria and dissociation constants. The calcium carbonate-water-carbon dioxide system is discussed in terms of these elementary concepts. Then a computer program available on the Internet is used, together with realistic parameters for tropical seawater, to calculate the extent of calcium carbonate supersaturation with the current atmospheric concentration of carbon dioxide and that predicted for the beginning of the next century.

Weston, Ralph E., Jr.

2000-12-01

287

Microfacies and diagenesis of older Pleistocene (pre-last glacial maximum) reef deposits, Great Barrier Reef,  

E-print Network

Expedition 325, 34 holes were drilled along five transects in front of the Great Barrier Reef of Australia, Great Barrier Reef Environmental Changes, Integrated Ocean Drilling Program, microfacies, PleistoceneMicrofacies and diagenesis of older Pleistocene (pre-last glacial maximum) reef deposits, Great

Schöne, Bernd R.

288

Estimates of adult and juvenile mortality for labrid fishes at One Tree Reef, Great Barrier Reef  

Microsoft Academic Search

Few estimates of natural mortality have been reported for coral reef fishes, yet this information is essential for predicting the effects of recruitment fluctuations on adult populations. In this study, mortality of adult (10 species) and juvenile (11 species) labrid fishes resident on ten isolated patch reefs in One Tree Lagoon, southern Great Barrier Reef, was estimated by visual censuses

G. J. Eckert

1987-01-01

289

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

NASA Astrophysics Data System (ADS)

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.

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

2011-09-01

290

CONDITION OF CORAL REEF ECOSYSTEMS IN CENTRAL-SOUTHERN QUINTANA ROO (PART 2: REEF FISH COMMUNITIES)  

Microsoft Academic Search

Increases of fishing and tourism threaten the natural relationships between reef fish communities and their environments. All species of reef fishes were visually assessed in the central and southern Mexican Caribbean in eight fringing reefs, four of which are in a protected biosphere reserve. The sampling design included three spatial scales from tens of meters to tens of kilometers. A

ENRIQUE NÚÑEZ-LARA; CARLOS GONZÁLEZ-SALAS; MIGUEL A. RUIZ-ZÁRATE; ROBERTO HERNÁNDEZ-LANDA; J. ERNESTO ARIAS-GONZÁLEZ

291

Effects of fishing on tropical reef associated shark populations on the Great Barrier Reef  

Microsoft Academic Search

Three data sets were examined to define the level of interaction of reef associated sharks with the commercial Coral Reef Fin Fish Fishery within the Great Barrier Reef (GBR). Data were examined from fishery logbooks, an observer program within the fishery and a fishery-independent survey conducted as part of the Effects of Line Fishing (ELF) Experiment. The majority of the

M. R. Heupel; A. J. Williams; D. J. Welch; A. Ballagh; B. D. Mapstone; G. Carlos; C. Davies; C. A. Simpfendorfer

2009-01-01

292

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

Microsoft Academic Search

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

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

2011-01-01

293

ReefLink Database: A decision support tool for Linking Coral Reefs and Society Through Systems Thinking  

EPA Science Inventory

Coral reefs provide the ecological foundation for productive and diverse fish and invertebrate communities that support multibillion dollar reef fishing and tourism industries. Yet reefs are threatened by growing coastal development, climate change, and over-exploitation. A key i...

294

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

NASA Astrophysics Data System (ADS)

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.

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

2012-06-01

295

Community ecology of mesophotic coral reef ecosystems  

Microsoft Academic Search

Given the global degradation of shallow-water coral reef ecosystems resulting from anthropogenic activities, mesophotic coral\\u000a reef ecosystems (MCEs) are gaining attention because they are generally considered a de facto refuge for shallow-water species.\\u000a Despite their inferred importance, MCEs remain one of the most understudied reef habitats, and basic information on the taxonomic\\u000a composition, depth range, habitat preferences, and abundance and

S. E. Kahng; J. R. Garcia-Sais; H. L. Spalding; E. Brokovich; D. Wagner; E. Weil; L. Hinderstein; R. J. Toonen

2010-01-01

296

Coral reef ecosystems and anthropogenic climate change  

Microsoft Academic Search

Coral reef ecosystems are among the most biologically diverse ecosystems on the planet. In addition to their value in terms\\u000a of biodiversity, coral reefs provide food and resources for over 500 million people. Despite their importance, coral reefs\\u000a are declining at a rapid rate (1–2% per year) as a result of a range of local (e.g., overexploitation of fisheries, declining\\u000a water

Ove Hoegh-Guldberg

2011-01-01

297

Atlantic coral reefs: the transplantation alternative  

Microsoft Academic Search

Although all of the world’s coral reef regions have suffered degradation due to direct and indirect human influences, only\\u000a the Western Atlantic reefs have declined to the extent that their continued existence appears to be in jeopardy. Of a once\\u000a flourishing reef system, only about 10% is still alive and it is depauperate in terms of the food web diversity

John C. Briggs

2009-01-01

298

Rigs to reefs: a petroleum industry perspective  

E-print Network

are in the Gulf of Nexico. These structures are, in effect, de facto artificial reefs, providing marine habitat while producing oil and gas. However, these structures are removed once hydrocarbon production ceases. With removal goes the loss of important... cost provides an economic disincentive to companies to participate in a rigs-to-reefs effort. The costs can be reduced by creating additional artificial reef sites, particularly sites close to areas where offshore platforms are located...

Dubose, William Perry

1988-01-01

299

Artificial reefs: from waste to resources  

Microsoft Academic Search

Waste materials, often referred to as “materials-of-opportunity,” have been the primary components used for constructing artificial reefs. Ships, barges, airplanes, automobiles, concrete debris, tires, and many other waste items have been disposed of at sea, with the added benefit of providing artificial reef habitat for environmental enhancement, fishing reefs, and interesting dive sites for eco-tourism. The latest development in artificial

Lee E. Harris; Benjamin J. Mostkoff; G. Zadikoff

1996-01-01

300

Climate change and coral reef connectivity  

Microsoft Academic Search

This review assesses and predicts the impacts that rapid climate change will have on population connectivity in coral reef\\u000a ecosystems, using fishes as a model group. Increased ocean temperatures are expected to accelerate larval development, potentially\\u000a leading to reduced pelagic durations and earlier reef-seeking behaviour. Depending on the spatial arrangement of reefs, the\\u000a expectation would be a reduction in dispersal

P. L. Munday; J. M. Leis; J. M. Lough; C. B. Paris; M. J. Kingsford; M. L. Berumen; J. Lambrechts

2009-01-01

301

Assessing Coral Reefs on a Pacific-Wide Scale Using the Microbialization Score  

PubMed Central

The majority of the world's coral reefs are in various stages of decline. While a suite of disturbances (overfishing, eutrophication, and global climate change) have been identified, the mechanism(s) of reef system decline remain elusive. Increased microbial and viral loading with higher percentages of opportunistic and specific microbial pathogens have been identified as potentially unifying features of coral reefs in decline. Due to their relative size and high per cell activity, a small change in microbial biomass may signal a large reallocation of available energy in an ecosystem; that is the microbialization of the coral reef. Our hypothesis was that human activities alter the energy budget of the reef system, specifically by altering the allocation of metabolic energy between microbes and macrobes. To determine if this is occurring on a regional scale, we calculated the basal metabolic rates for the fish and microbial communities at 99 sites on twenty-nine coral islands throughout the Pacific Ocean using previously established scaling relationships. From these metabolic rate predictions, we derived a new metric for assessing and comparing reef health called the microbialization score. The microbialization score represents the percentage of the combined fish and microbial predicted metabolic rate that is microbial. Our results demonstrate a strong positive correlation between reef microbialization scores and human impact. In contrast, microbialization scores did not significantly correlate with ocean net primary production, local chla concentrations, or the combined metabolic rate of the fish and microbial communities. These findings support the hypothesis that human activities are shifting energy to the microbes, at the expense of the macrobes. Regardless of oceanographic context, the microbialization score is a powerful metric for assessing the level of human impact a reef system is experiencing. PMID:22970122

McDole, Tracey; Nulton, James; Barott, Katie L.; Felts, Ben; Hand, Carol; Hatay, Mark; Lee, Hochul; Nadon, Marc O.; Nosrat, Bahador; Salamon, Peter; Bailey, Barbara; Sandin, Stuart A.; Vargas-Angel, Bernardo; Youle, Merry; Zgliczynski, Brian J.; Brainard, Russell E.; Rohwer, Forest

2012-01-01

302

Assessing coral reefs on a Pacific-wide scale using the microbialization score.  

PubMed

The majority of the world's coral reefs are in various stages of decline. While a suite of disturbances (overfishing, eutrophication, and global climate change) have been identified, the mechanism(s) of reef system decline remain elusive. Increased microbial and viral loading with higher percentages of opportunistic and specific microbial pathogens have been identified as potentially unifying features of coral reefs in decline. Due to their relative size and high per cell activity, a small change in microbial biomass may signal a large reallocation of available energy in an ecosystem; that is the microbialization of the coral reef. Our hypothesis was that human activities alter the energy budget of the reef system, specifically by altering the allocation of metabolic energy between microbes and macrobes. To determine if this is occurring on a regional scale, we calculated the basal metabolic rates for the fish and microbial communities at 99 sites on twenty-nine coral islands throughout the Pacific Ocean using previously established scaling relationships. From these metabolic rate predictions, we derived a new metric for assessing and comparing reef health called the microbialization score. The microbialization score represents the percentage of the combined fish and microbial predicted metabolic rate that is microbial. Our results demonstrate a strong positive correlation between reef microbialization scores and human impact. In contrast, microbialization scores did not significantly correlate with ocean net primary production, local chla concentrations, or the combined metabolic rate of the fish and microbial communities. These findings support the hypothesis that human activities are shifting energy to the microbes, at the expense of the macrobes. Regardless of oceanographic context, the microbialization score is a powerful metric for assessing the level of human impact a reef system is experiencing. PMID:22970122

McDole, Tracey; Nulton, James; Barott, Katie L; Felts, Ben; Hand, Carol; Hatay, Mark; Lee, Hochul; Nadon, Marc O; Nosrat, Bahador; Salamon, Peter; Bailey, Barbara; Sandin, Stuart A; Vargas-Angel, Bernardo; Youle, Merry; Zgliczynski, Brian J; Brainard, Russell E; Rohwer, Forest

2012-01-01

303

Onondage pinnacle reefs in New York State  

SciTech Connect

Onondaga pinnacle reefs, part of the Onondaga Formation, developed in an epeiric setting of the lowermost Middle Devonian (Eifelian). The reefs were initiated as coral-crinoidal mounds in the Edgecliff Member of the formation. Whereas most Devonian reefs are composed of rugose corals. Coral is the predominant kind of fossil, followed by crinoids, brachiopods, mollusks, undifferentiated skeletal debris, and possible sponges. The initial mineralogy of the corals is inferred to have been calcite. The porosity of these reefs is almost unique among reef reservoirs. most reefs produce from secondary or diagenetic porosity; by contrast Onondaga reefs display primary intracoralline or framework porosity. Between framework builders and/or skeletal particles cryptocrystalline/microcrystalline cement fills pores. As observed in modern reefs this kind of cement resembles micrite, but probable formed as high-magnesian calcite in a high-energy setting. Syntaxial or rim cement common lines crinoid particles. Some of these pinnacle reefs, formerly gas producers, are presently under development as gas-storage reservoirs.

Friedman, G.M. [Brooklyn College and Graduate School of CUNY, Brooklyn, NY (United States)

1995-09-01

304

Satellite Remote Sensing of Coral Reefs  

NSDL National Science Digital Library

Coral reefs are one of the most endangered ecosystems as coral reef coverage has declined dramatically in the past three decades. In recent years, satellite remote sensing has become a popular and effective mapping tool for ecological studies, especially in marine science. This lesson plan designed for high school science students demonstrates how marine scientists use satellite remote sensing to gather detailed information about coral reefs worldwide. An in-depth review of both remote sensing and coral reefs is also included in this article.

Palandro, David; Muller-Karger, Frank; Kusek, Kristen; Thoms, Kristin; Greely, Teresa

2005-09-01

305

Impacts of Artificial Reefs on Surrounding Ecosystems  

NASA Astrophysics Data System (ADS)

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

Manoukian, Sarine

306

Nocturnal relocation of adult and juvenile coral reef fishes in response to reef noise  

NASA Astrophysics Data System (ADS)

Juvenile and adult reef fishes often undergo migration, ontogenic habitat shifts, and nocturnal foraging movements. The orientation cues used for these behaviours are largely unknown. In this study, the use of sound as an orientation cue guiding the nocturnal movements of adult and juvenile reef fishes at Lizard Island, Great Barrier Reef was examined. The first experiment compared the movements of fishes to small patch reefs where reef noise was broadcast, with those to silent reefs. No significant responses were found in the 79 adults that were collected, but the 166 juveniles collected showed an increased diversity each morning on the reefs with broadcast noise, and significantly greater numbers of juveniles from three taxa (Apogonidae, Gobiidae and Pinguipedidae) were collected from reefs with broadcast noise. The second experiment compared the movement of adult and juvenile fishes to reefs broadcasting high (>570 Hz), or low (<570 Hz) frequency reef noise, or to silent reefs. Of the 122 adults collected, the highest diversity was seen at the low frequency reefs; and adults from two families (Gobiidae and Blenniidae) preferred these reefs. A similar trend was observed in the 372 juveniles collected, with higher diversity at the reefs with low frequency noises. This preference was seen in the juvenile apogonids; however, juvenile gobiids were attracted to both high and low sound treatments equally, and juvenile stage Acanthuridae preferred the high frequency noises. This evidence that juvenile and adult reef fishes orientate with respect to the soundscape raises important issues for management, conservation and the protection of sound cues used in natural behaviour.

Simpson, S. D.; Jeffs, A.; Montgomery, J. C.; McCauley, R. D.; Meekan, M. G.

2008-03-01

307

Ecological, Radiological, and Toxicological Effects of Naval Bombardment on the Coral Reefs of Isla de Vieques, Puerto Rico  

Microsoft Academic Search

\\u000a Between 1943 and 2003, land and sea areas on the eastern end of Isla de Vieques, Puerto Rico were used as a naval gunnery\\u000a and bombing range. Viequean coral reefs are littered with leaking and unexploded ordnance (UXO). Radiological, biological,\\u000a and chemical surveys were conducted to assay the health of these coral reefs.\\u000a \\u000a \\u000a Biotic surveys revealed a statistically significant inverse

James W. Porter; James V. Barton; Cecilia Torres

308

From ridge to reef—linking erosion and changing watersheds to impacts on the coral reef ecosystems of Hawai‘i and the Pacific Ocean  

USGS Publications Warehouse

Coral reef ecosystems are threatened by unprecedented watershed changes in the United States and worldwide. These ecosystems sustain fishing and tourism industries essential to the economic survival of many communities. Sediment, nutrients, and pollutants from watersheds are increasingly transported to coastal waters, where these contaminants damage corals. Although pollution from watersheds is one of many factors threatening coral survival, it is one that local people can have a profound influence on. U.S. Geological Survey scientists are using mapping, monitoring, and computer modeling to better forecast the effects of watershed changes on reef health. Working with communities in Hawai‘i and on other U.S. islands in the Pacific, they are helping to provide the science needed to make informed decisions on watershed and coral reef management.

Stock, Jonathan D.; Cochran, Susan A.; Field, Michael E.; Jacobi, James D.; Tribble, Gordon

2011-01-01

309

Mineralogy, composition, and alteration of Mars Pathfinder rocks and soils: Evidence from multispectral, elemental, and magnetic data on terrestrial analogue, SNC meteorite, and Pathfinder samples  

Microsoft Academic Search

Major element, multispectral, and magnetic properties data were obtained at Ares Vallis during the Mars Pathfinder mission. To understand the compositional, mineralogical, and process implications of these data, we obtained major element, mineralogical, and magnetic data for well-crystalline and nanophase ferric minerals, terrestrial analogue samples with known geologic context, and SNC meteorites. Analogue samples include unaltered, palagonitic, and sulfatetic tephra

Richard V. Morris; Tad D. Shelfer; Andreas C. Scheinost; Nancy W. Hinman; George Furniss; Janice L. Bishop; Douglas W. Ming; Carlton C. Allen; Daniel T. Britt

2000-01-01

310

The Earth System Science Pathfinder Orbiting Carbon Observatory (OCO) Mission  

NASA Technical Reports Server (NTRS)

A viewgraph presentation describing the Earth System Science Pathfinder Orbiting Carbon Observatory (OCO) Mission is shown. The contents include: 1) Why CO2?; 2) What Processes Control CO2 Sinks?; 3) OCO Science Team; 4) Space-Based Measurements of CO2; 5) Driving Requirement: Precise, Bias-Free Global Measurements; 6) Making Precise CO2 Measurements from Space; 7) OCO Spatial Sampling Strategy; 8) OCO Observing Modes; 9) Implementation Approach; 10) The OCO Instrument; 11) The OCO Spacecraft; 12) OCO Will Fly in the A-Train; 13) Validation Program Ensures Accuracy and Minimizes Spatially Coherent Biases; 14) Can OCO Provide the Required Precision?; 15) O2 Column Retrievals with Ground-based FTS; 16) X(sub CO2) Retrieval Simulations; 17) Impact of Albedo and Aerosol Uncertainty on X(sub CO2) Retrievals; 18) Carbon Cycle Modeling Studies: Seasonal Cycle; 19) Carbon Cycle Modeling Studies: The North-South Gradient in CO2; 20) Carbon Cycle Modeling Studies: Effect of Diurnal Biases; 21) Project Status and Schedule; and 22) Summary.

Crisp, David

2003-01-01

311

The Scatterometer Climate Record Pathfinder: Tools for Climate Change Studies  

NASA Astrophysics Data System (ADS)

While originally designed for wind measurement over the ocean, scatterometers have proven to be very effective in monitoring land cover and ice conditions as well. Scatterometer data is being operationally used for iceberg tracking and sea ice extent mapping. The frequent, global measurements make the instrument particularly well suited for global monitoring and the long-time series of scatterometer measurements dating back to SASS provide a valuable baseline for studies of climate change. For this reason the NASA Scatterometer Climate Record Pathfinder (SCP) project is generating a climate data record from the series of historic and ongoing, and approved scatterometer missions. Selected data is currently available from the SCP at URL http://www.scp.byu.edu/ in the form of resolution-enhanced backscatter image time series. A variety of tools for analyzing the image time series have been developed. The application of QuikSCAT data to climate change in Greenland and sea ice motion in the Arctic is illustrated. By comparing QuikSCAT with NSCAT and SASS data, long-term scatterometer-observed changes in Greenland are related to annual variations in melt extent and snow accumulation. Qu ikSCAT sampling enables high spatial resolution evaluation of the diurnal melt cycle. We demonstrate the value of the scatterometer data to augment passive microwave measurements by using PCA. The scatterometer data plays a key role in helping to discriminate physical changes in the Greenland firn from surface temperature effects.

Long, D. G.; Jensen, M. A.

2001-12-01

312

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.

313

Model Checking Real Time Java Using Java PathFinder  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

314

Science With The Australian Square Kilometre Array Pathfinder  

E-print Network

The future of cm and m-wave astronomy lies with the Square Kilometre Array (SKA), a telescope under development by a consortium of 17 countries that will be 50 times more sensitive than any existing radio facility. Most of the key science for the SKA will be addressed through large-area imaging of the Universe at frequencies from a few hundred MHz to a few GHz. The Australian SKA Pathfinder (ASKAP) is a technology demonstrator aimed in the mid-frequency range, and achieves instantaneous wide-area imaging through the development and deployment of phased-array feed systems on parabolic reflectors. The large field-of-view makes ASKAP an unprecedented synoptic telescope that will make substantial advances in SKA key science. ASKAP will be located at the Murchison Radio Observatory in inland Western Australia, one of the most radio-quiet locations on the Earth and one of two sites selected by the international community as a potential location for the SKA. In this paper, we outline an ambitious science program for ASKAP, examining key science such as understanding the evolution, formation and population of galaxies including our own, understanding the magnetic Universe, revealing the transient radio sky and searching for gravitational waves.

Simon Johnston

2007-11-14

315

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

NASA Technical Reports Server (NTRS)

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.

Maslanik, James; Fowler, Charles; Scambos, Theodore

1999-01-01

316

Science With The Australian Square Kilometre Array Pathfinder  

E-print Network

The future of cm and m-wave astronomy lies with the Square Kilometre Array (SKA), a telescope under development by a consortium of 17 countries that will be 50 times more sensitive than any existing radio facility. Most of the key science for the SKA will be addressed through large-area imaging of the Universe at frequencies from a few hundred MHz to a few GHz. The Australian SKA Pathfinder (ASKAP) is a technology demonstrator aimed in the mid-frequency range, and achieves instantaneous wide-area imaging through the development and deployment of phased-array feed systems on parabolic reflectors. The large field-of-view makes ASKAP an unprecedented synoptic telescope that will make substantial advances in SKA key science. ASKAP will be located at the Murchison Radio Observatory in inland Western Australia, one of the most radio-quiet locations on the Earth and one of two sites selected by the international community as a potential location for the SKA. In this paper, we outline an ambitious science program for...

Johnston, Simon

2007-01-01

317

Science with ASKAP - the Australian Square Kilometre Array Pathfinder  

E-print Network

[ABRIDGED VERSION] The future of cm and m-wave astronomy lies with the Square Kilometre Array (SKA), a telescope under development by a consortium of 17 countries. The SKA will be 50 times more sensitive than any existing radio facility. A majority of the key science for the SKA will be addressed through large-area imaging of the Universe at frequencies from 300 MHz to a few GHz. The Australian SKA Pathfinder (ASKAP) is aimed squarely in this frequency range, and achieves instantaneous wide-area imaging through the development and deployment of phase-array feed systems on parabolic reflectors. This large field-of-view makes ASKAP an unprecedented synoptic telescope poised to achieve substantial advances in SKA key science. The central core of ASKAP will be located at the Murchison Radio Observatory in inland Western Australia, one of the most radio-quiet locations on the Earth and one of the sites selected by the international community as a potential location for the SKA. Following an introductory descriptio...

Johnston, Simon

2008-01-01

318

Science with the Australian Square Kilometre Array Pathfinder (ASKAP)  

E-print Network

The future of cm and m-wave astronomy lies with the Square Kilometre Array (SKA), a telescope under development by a consortium of 17 countries that will be 50 times more sensitive than any existing radio facility. Most of the key science for the SKA will be addressed through large-area imaging of the Universe at frequencies from a few hundred MHz to a few GHz. The Australian SKA Pathfinder (ASKAP) is a technology demonstrator aimed in the mid-frequency range, and achieves instantaneous wide-area imaging through the development and deployment of phased-array feed systems on parabolic reflectors. The large field-of-view makes ASKAP an unprecedented synoptic telescope that will make substantial advances in SKA key science. ASKAP will be located at the Murchison Radio Observatory in inland Western Australia, one of the most radio-quiet locations on the Earth and one of two sites selected by the international community as a potential location for the SKA. In this paper, we outline the ASKAP project and summarise ...

Johnston, Simon; Gupta, Neeraj

2009-01-01

319

Trajectory Based Heating and Ablation Calculations for MESUR Pathfinder Aeroshell  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

320

Inadequate Evaluation and Management of Threats in Australia's Marine Parks, Including the Great Barrier Reef, Misdirect Marine Conservation.  

PubMed

The magnificence of the Great Barrier Reef and its worthiness of extraordinary efforts to protect it from whatever threats may arise are unquestioned. Yet almost four decades after the establishment of the Great Barrier Reef Marine Park, Australia's most expensive and intensely researched Marine Protected Area, the health of the Reef is reported to be declining alarmingly. The management of the suite of threats to the health of the reef has clearly been inadequate, even though there have been several notable successes. It is argued that the failure to prioritise correctly all major threats to the reef, coupled with the exaggeration of the benefits of calling the park a protected area and zoning subsets of areas as 'no-take', has distracted attention from adequately addressing the real causes of impact. Australia's marine conservation efforts have been dominated by commitment to a National Representative System of Marine Protected Areas. In so doing, Australia has displaced the internationally accepted primary priority for pursuing effective protection of marine environments with inadequately critical adherence to the principle of having more and bigger marine parks. The continuing decline in the health of the Great Barrier Reef and other Australian coastal areas confirms the limitations of current area management for combating threats to marine ecosystems. There is great need for more critical evaluation of how marine environments can be protected effectively and managed efficiently. PMID:25358302

Kearney, Bob; Farebrother, Graham

2014-01-01

321

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

PubMed

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

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

2014-01-01

322

Coral Reef Community Composition in the Context of Disturbance History on the Great Barrier Reef, Australia  

PubMed Central

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

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

2014-01-01

323

Dynamic Stability of Coral Reefs on the West Australian Coast  

PubMed Central

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

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

324

Artificial Reefs--A Coastal Classroom Project.  

ERIC Educational Resources Information Center

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)

Dindo, John J.

1986-01-01

325

Wonders of the Living Reef The Invertebrates  

Microsoft Academic Search

The living reef is a realm of wonders. With a first look at a living reef, one is overwhelmed with the diversity in color and shape of the corals and fishes. But beneath this surface is an even more wondrous world, one of bizarre, alien creatures, some of which hardly resemble living animals. These \\

Scott Johnson

326

Coral reef restoration projects in Thailand  

Microsoft Academic Search

The degradation and deterioration of coral reefs in Thailand has continued for several decades due to pressures from fishery and tourism activities and, more recently, from bleaching. Several institutions and organizations, from both the government and the private sector, have been involved in programs to restore degraded coral reefs. The objectives, scales and methods of these restoration projects have varied

Thamasak Yeemin; Makamas Sutthacheep; Rattika Pettongma

2006-01-01

327

Development of contemporary Eastern Pacific coral reefs  

Microsoft Academic Search

An overview of oceanographic conditions prevailing in the tropical Eastern Pacific Ocean suggests that the entire region is environmentally marginal for coral-reef development. The principal features of this environment are a strong, permanent, shallow thermocline and an annual north-south migration of the Intertropical Convergence resulting in wet and dry seasons. Along tropical Eastern Pacific continental margins structural coral reefs are

T. F. Dana

1975-01-01

328

REEF MANAGER'S GUIDE TO CORAL BLEACHING  

EPA Science Inventory

A Reef Manager's Guide to Coral Bleaching is the result of a collaborative effort by over 50 scientists and managers to: (1) engage in information-sharing in the areas of coral reef science and management for climate change and coral bleaching; and (2) compile a management tool ...

329

Along-Track Reef Imaging System (ATRIS)  

USGS Publications Warehouse

"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.

Brock, John; Zawada, Dave

2006-01-01

330

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....

331

Subtropical Biotic Fringing Reefs as Ecological Laboratories.  

ERIC Educational Resources Information Center

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)

Hunt, Jeffrey W.

1980-01-01

332

Wave Forced Normal Modes on Fringing Reefs  

NASA Astrophysics Data System (ADS)

In an effort to assess wave-driven coastal inundation at the shoreline of fringing reefs, pressure and current observations were collected at reefs on Guam (Ipan) and Oahu, Hawaii (Mokuleia) as part of the PILOT (Pacific Island Land-Ocean Typhoon) experiment. Similar to dissipative sandy beaches, nearshore surface elevation at both reefs is dominated by energy in the infragravity frequency band. Coherent infragravity oscillations across the reef tend to occur at discrete frequencies and with standing wave cross-shore structures that are consistent with open basin resonant modes. The modes are forced by swell wave groups, similar to a time-dependent setup. The resonant modes are most apparent during energetic wave events, in part because wave setup over the reef increases the low mode resonant frequencies to a range that is conducive to wave group forcing. Evidence of the excitation of resonant modes during tropical storm Man-Yi at Ipan, Guam is presented.

Pequignet, A. N.; Becker, J. M.; Merrifield, M. M.; Aucan, J.

2008-12-01

333

Pathfinder ground preparations prior to altitude record setting flight of 71,500 feet  

NASA Technical Reports Server (NTRS)

Technicians make final adjustments on the solar-powered Pathfinder remotely piloted research aircraft prior to the craft's taking off on a flight which established a new unofficial world's altitude record for both propellor-driven and solar-powered aircraft. The new record of more than 71,500 feet was set during a 14 1/2-hour flight July 7, 1997, from the U.S. Navy's Pacific Missile Range Facility (PMRF) at Barking Sands, Kauai, Hawaii. The new altitude record is subject to verification by the National Aeronautics Association. The Pathfinder took off at 8:34 a.m. HDT, passed its previous record altitude of 67,350 feet about 2:45 p.m., and then reached its new mark at about 4 p.m. Controllers on the ground then initiated a slow decent, and Pathfinder landed seven hours later at 11:05 p.m. HDT. The experimental Boeing Condor remotely-piloted aircraft had held the previous record for propellor-driven craft of 67,028 feet. The Pathfinder had exceeded that height on a previous flight on June 9, 1997, but not by a large enough margin to be considered a new record. 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.)

1997-01-01

334

Porosity evolution of upper Miocene reefs, Almeria Province, Southern Spain  

Microsoft Academic Search

In the reef cores and fore-reef breccia beds, porosity in both primary and postdepositional. Primary porosity is of three types: (a) boring clam holes in the scleractinian coral heads, cemented reef rocks, and breccias; (b) intraparticle porosity within the corals, Halimeda plates, and vermetid worm tubes; and (c) interparticle porosity between bioclastic fragments and in the reef breccia. Postdepositional moldic

A. K. Armstrong; P. D. Jr. Snavely; W. O. Addicott

1980-01-01

335

SIGHTINGS OF HUMPBACK WHALES IN GREAT BARRIER REEF WATERS  

E-print Network

SIGHTINGS OF HUMPBACK WHALES IN GREAT BARRIER REEF WATERS MARK L. SIMMONS* AND HELENE MARSH*+ ABSTRACT Oral J-ristoryintewiews indicate that humpback whales used to winter in Great Barrier Reef waters in the Great Barrier Reef lagoon. Some females "pp"...,ity ."r* before they reach reef waters. Hump6acks

Marsh, Helene

336

Science and management of coral reefs: problems and prospects  

Microsoft Academic Search

It should be recognised that many principles of reef management do not need further research, as they involve changing human behaviour and activities in order to remove or reduce impacts on reefs. Much of the time of a reef manager is taken up with social, economic and political issues: the integration of reef management into broad coastal zone management objectives;

S. M. Wells

1995-01-01

337

Community Structure of Pleistocene Coral Reefs of Curacao, Netherlands Antilles  

Microsoft Academic Search

The Quaternary fossil record of living coral reefs is fundamental for un- derstanding modern ecological patterns. Living reefs generally accumulate in place, so fossil reefs record a history of their former biological inhabitants and physical environments. Reef corals record their ecological history especially well because they form large, resistant skeletons, which can be identified to species. Thus, presence-absence and relative

John M. Pandolfi; Jeremy B. C. Jackson

2001-01-01

338

A Theoretical Model of Pattern Formation in Coral Reefs  

E-print Network

A Theoretical Model of Pattern Formation in Coral Reefs Susannah Mistr and David Bercovici to flow are qualitatively supported on both a colonial and a regional reef scale. Key words: coral reefs; pattern formation; self- organization; colonial organisms. INTRODUCTION Coral reefs are composed of small

339

Parrotfish abundance and selective corallivory on a Belizean coral reef  

E-print Network

Parrotfish abundance and selective corallivory on a Belizean coral reef Randi D. Rotjan *, Sara M of coral reef communities because they consume macroalgae that would otherwise outcompete reef grazing by parrotfish on particular coral species, differences in grazing incidence among reef habitats

Lewis, Sara

340

A Global Estimate of the Number of Coral Reef Fishers  

PubMed Central

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

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

2013-01-01

341

Climate Change, Human Impacts, and the Resilience of Coral Reefs  

Microsoft Academic Search

The diversity, frequency, and scale of human impacts on coral reefs are increasing to the extent that reefs are threatened globally. Projected increases in carbon dioxide and temperature over the next 50 years exceed the conditions under which coral reefs have flourished over the past half-million years. However, reefs will change rather than disappear entirely, with some species already showing

T. P. Hughes; A. H. Baird; D. R. Bellwood; M. Card; S. R. Connolly; C. Folke; R. Grosberg; O. Hoegh-Guldberg; J. B. C. Jackson; J. Kleypas; J. M. Lough; P. Marshall; M. Nyström; S. R. Palumbi; J. M. Pandolfi; B. Rosen; J. Roughgarden

2003-01-01

342

Segregation and pathfinding of callosal axons through EphA3 signaling.  

PubMed

The corpus callosum, composed of callosal axons, is the largest structure among commissural connections in eutherian animals. Axon pathfinding of callosal neurons has been shown to be guided by intermediate targets, such as midline glial structures. However, it has not yet been understood completely how axon-axon interactions, another major mechanism for axon pathfinding, are involved in the pathfinding of callosal neurons. Here, we show that callosal axons from the medial and lateral regions of the mouse cerebral cortex pass through the dorsal and ventral parts, respectively, of the corpus callosum. Using an explant culture system, we observed that the axons from the medial and lateral cortices were segregated from each other in vitro, and that this segregation was attenuated by inhibition of EphA3 signaling. We also found that knockdown of EphA3, which is preferentially expressed in the lateral cortex, resulted in disorganized segregation of the callosal axons and disrupted axon pathfinding in vivo. These results together suggest the role of axonal segregation in the corpus callosum, mediated at least in part by EphA3, in correct pathfinding of callosal neurons. PMID:22072676

Nishikimi, Mitsuaki; Oishi, Koji; Tabata, Hidenori; Torii, Kenichi; Nakajima, Kazunori

2011-11-01

343

Edgecliff reefs - Devonian temperate water carbonate deposition  

SciTech Connect

The Middle Devonian Edgecliff Member of the Onondaga Formation in New York and Ontario, Canada, is a coral-rich, reefy,' crinoidal grainstone/packstone. The reefs contain only rare stromatoporoids and are devoid of algae, having been constructed by a fauna of mound and thicket-forming branching colonial rugosans, and large sheet favositids that populated grainstone/packstone flank beds and banks. Despite the restricted fauna, the reefs display a variety of growth patterns. Rugosan mounds range in size from 2-3 m diameter by 1 m thick, up to 230 m diameter by 15 m thick. Composite structures consist of interbedded rugosan buildups and packstone/grainstone flanks, ranging from shield-shaped reefs (240 m diameter by 6 m thick) in which the rugosans occur only as thickets, to pinnacle reefs (up to 3 km diameter by 60 m thick) in which rugosan mounds are interbedded with crinoidal flanks. Geographic distribution of these reef types and analysis of surrounding facies suggests that reef growth pattern was controlled by water depth and local rate of subsidence. Despite superfacial resemblance to modern deep water ahermatypic coral mounds and thickets, abundant coral breakage and overturning, and erosion of at least one reef core during an intermediate stage of reef growth supports a shallow water origin of these reefs. It is suggested that the Edgecliff and its reefs represent an example of Devonian cool water carbonate deposition, a hypothesis supported by a trend of increasing stromatoporoid abundance westwards across New York (in the direction of the paleo-equator).

Wolosz, T.H. (State Univ. of New York, Plattsburgh (United States))

1991-03-01

344

A novel reef coral symbiosis  

NASA Astrophysics Data System (ADS)

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.

Pantos, O.; Bythell, J. C.

2010-09-01

345

Islands, Reefs, and a Hotspot  

NSDL National Science Digital Library

In this lesson students investigate the formation of the Hawaiian archipelago to see what geological processes produced the different physical forms seen among the Hawaiian Islands. Students will be able to describe eight stages in the formation of islands in the Hawaiian archipelago and will describe the movement of tectonic plates in the region including submarine volcanic eruptions, caldera formation, erosion, coral reef building, and atoll stages. They will also learn how a combination of hotspot activity and tectonic plate movement could produce the arrangement of seamounts observed in the Hawaiian archipelago.

Mel Goodwin

346

Ecology of a Caribbean coral reef. The Porites reef-flat biotope: Part II. Plankton community with evidence for depletion  

Microsoft Academic Search

A quantitative assessment of drifting net plankton crossing a reef-flat biotope was obtained on a Caribbean coral reef. The spatial distribution and abundance of plankton were sampled to provide estimates of the removal of this potential food resource by suspension-feeding populations. Sampling was largely confined to the reef flat and adjacent waters of Laurel Cay, a flourishing coral reef present

P. W. Glynn

1973-01-01

347

Assessing the effects of non-point source pollution on American Samoa's coral reef communities.  

PubMed

Surveys were completed on Tutuila Island, American Samoa, to characterize reef development and assess the impacts of non-point source pollution on adjacent coral reefs at six sites. Multivariate analyses of benthic and coral community data found similar modern reef development at three locations; Aoa, Alofau, and Leone. These sites are situated in isolated bays with gentle sloping foundations. Aoa reefs had the highest estimates of crustose coralline algae cover and coral species richness, while Leone and Alofau showed high abundances of macroalgae and Porites corals. Aoa has the largest reef flat between watershed discharge and the reef slope, and the lowest human population density. Masefau and Fagaalu have a different geomorphology consisting of cemented staghorn coral fragments and steep slopes, however, benthic and coral communities were not similar. Benthic data suggest Fagaalu is heavily impacted compared with all other sites. Reef communities were assessed as bio-criteria indicators for waterbody health, using the EPA aquatic life use support designations of (1) fully supportive, (2) partially supportive, and (3) non-supportive for aquatic life. All sites resulted in a partially supportive ranking except Fagaalu, which was non-supportive. The results of this rapid assessment based upon relative benthic community measures are less desirable than long-term dataset analyses from monitoring programs, however it fills an important role for regulatory agencies required to report annual waterbody assessments. Future monitoring sites should be established to increase the number of replicates within each geological and physical setting to allow for meaningful comparisons along a gradient of hypothesized pollution levels. PMID:16418902

Houk, Peter; Didonato, Guy; Iguel, John; Van Woesik, Robert

2005-08-01

348

LISA Pathfinder testing TeVeS/MOND  

NASA Astrophysics Data System (ADS)

The LISA Pathfinder (LPF) mission will launch in 2012 to test key technologies for LISA and perform a high precision measurement of free-fall in the environment of the Sun-Earth Lagrangian point L1. The configuration onboard LPF -envisioning 2 test masses in mutual free-fall with interferometric position tracking -makes it the best precision free-fall gradiometer ever flown in space. Precision studies of several possible orbit trajectories show that LPF could cross near the saddle point of the Sun-Earth system, thus meeting the conditions to measure departures from pure tensor Newton-Einstein gravity predictions. In the specific case we've considered TeVeS, an interesting relativistic formulation of the old MOND paradigm, and followed a recent adaptation for low speeds around the Earth-Sun saddle-point. LPF could graze or cross through the TeVeS bubble and show a non-standard behavior in the mutual displacement of the test masses resulting from the anomalous non-Newtonian acceleration in the bubble. We'll show the orbit conditions for LPF to reach the TeVeS bubble premises, the type of signal to expect and sketch the type of data analysis to single the effect out the Solar System background noises. Moreover, we'll tackle the problem of further tests of gravity, like generic departures from the 1/r2 law. At this stage LPF is bound to perform the first direct scientific measurement about the TeVeS bubble, confirming the presence of non standard effects, ruling them out or clearly reducing their parameter space.

Trenkel, Christian; Armano, Michele; Sumner, T. J.

349

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

NASA Technical Reports Server (NTRS)

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.

Sadin, Stanley R.; Rosen, Robert

1987-01-01

350

Preliminary Findings of the Photovoltaic Cell Calibration Experiment on Pathfinder Flight 95-3  

NASA Technical Reports Server (NTRS)

The objective of the photovoltaic (PV) cell calibration experiment for Pathfinder was to develop an experiment compatible with an ultralight UAV to predict the performance of PV cells at AM0, the solar spectrum in space, using the Langley plot technique. The Langley plot is a valuable technique for this purpose and requires accurate measurements of air mass (pressure), cell temperature, solar irradiance, and current-voltage(IV) characteristics with the cells directed normal to the direct ray of the sun. Pathfinder's mission objective (95-3) of 65,000 ft. maximum altitude, is ideal for performing the Langley plot measurements. Miniaturization of electronic data acquisition equipment enabled the design and construction of an accurate and light weight measurement system that meets Pathfinder's low payload weight requirements.

Vargas-Aburto, Carlos

1997-01-01

351

Photogrammetric analysis of horizon panoramas: The Pathfinder landing site in Viking orbiter images  

USGS Publications Warehouse

Tiepoint measurements, block adjustment techniques, and sunrise/sunset pictures were used to obtain precise pointing data with respect to north for a set of 33 IMP horizon images. Azimuth angles for five prominent topographic features seen at the horizon were measured and correlated with locations of these features in Viking orbiter images. Based on this analysis, the Pathfinder line/sample coordinates in two raw Viking images were determined with approximate errors of 1 pixel, or 40 m. Identification of the Pathfinder location in orbit imagery yields geological context for surface studies of the landing site. Furthermore, the precise determination of coordinates in images together with the known planet-fixed coordinates of the lander make the Pathfinder landing site the most important anchor point in current control point networks of Mars. Copyright 1999 by the American Geophysical Union.

Oberst, J.; Jaumann, R.; Zeitler, W.; Hauber, E.; Kuschel, M.; Parker, T.; Golombek, M.; Malin, M.; Soderblom, L.

1999-01-01

352

Coral Reef Adventure Fun Zone  

NSDL National Science Digital Library

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.

Science NetLinks (AAAS;)

2007-04-29

353

Sediment and Turbidity Associated with Offshore Dredging Increase Coral Disease Prevalence on Nearby Reefs  

PubMed Central

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

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

354

Observation of early photons from gamma-ray bursts with the Lomonosov / UFFO-pathfinder  

NASA Astrophysics Data System (ADS)

UFFO-pathfinder is a pioneering space mission to observe the early evolution of Gamma-ray Bursts using a fast slewing strategy. It consists of the Slewing Mirror Telescope, for rapid pointing at UV/optical wavelengths and the UFFO Burst Alert and Trigger Telescope. It has a total weight of ˜ 20 kg and will be launched on-board the Russian Lomonosov satellite at the end of 2015. The instrumental details of UFFO-pathfinder and its performance are discussed briefly here.

Jeong, S.; Brandt, S.; Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen, P.; Connell, P.; Eyles, C.; Huang, M.-H. A.; Kim, J. E.; Kim, M. B.; Kim, S.-W.; Lee, J.; Lim, H.; Liu, T.-C.; Nam, J. W.; Park, H. W.; Park, I. H.; Panasyuk, M. I.; Reglero, V.; Ripa, J.; Rodrigo, J. M.; Svertilov, S.; Vedenkin, N.; Yashin, I.

2014-12-01

355

MARS PATHFINDER 'SOJOURNER' ROVER 1:1 SCALE DUPLICATE TEST VEHICLE  

NASA Technical Reports Server (NTRS)

Mars Pathfinder's 'Sojourner' rover l:l scale duplicate test vehicle undergoes Earthbound tests at the Kennedy Space Center. The launch of NASA's Mars Pathfinder spacecraft aboard a McDonnell Douglas Delta II rocket is scheduled for Monday, Dec. 2, at 2:09:11 a.m. EST. This is a single instantaneous target launch time without a second opportunity on that day. Liftoff will occur from Pad B at Launch Complex 17 on Cape Canaveral Air Station, Fla. There is a 24-day launch opportunity which extends through Dec. 31.

1996-01-01

356

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

NASA Technical Reports Server (NTRS)

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.

Keller, H. Uwe

1994-01-01

357

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

USGS Publications Warehouse

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.

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

358

Global disparity in the ecological benefits of reducing carbon emissions for coral reefs  

NASA Astrophysics Data System (ADS)

Even if carbon emissions are reduced drastically in the next decade the amount of carbon already stored in the atmosphere would lead to the occurrence of extreme thermal events every three to four years between 2040 and 2080. This time lag on the effect of reducing emissions suggests that the benefits of carbon emission reduction on the health of coral reefs will be noticeable only in the long term. Here, we use a spatially explicit ecosystem model to compare the potential ecosystem benefits that Caribbean and Pacific reefs could gain from reductions in carbon emissions, and the timescale of these benefits. We found that whereas the effect of a reduction in emissions on Caribbean reefs will be modest and realized only in the long term (more than 60 years), Pacific reefs would start to show benefits within the first half of this century. Moreover, it seems that Pacific reefs have the potential to maintain their ecological integrity and ecosystem state in the mid- to long term if carbon emissions are reduced, but only if plate-like corals are present.

Ortiz, Juan Carlos; Bozec, Yves-Marie; Wolff, Nicholas H.; Doropoulos, Christopher; Mumby, Peter J.

2014-12-01

359

Halimeda biomass, growth rates and sediment generation on reefs in the central great barrier reef province  

Microsoft Academic Search

The average biomass ofHalimeda per m2 of solid substratum increased progressively on a series of reefs situated at increasing distances from the shore in the central\\u000a Great Barrier Reef. There was none on a reef close inshore, increasing to nearly 500 g m?2 total biomass (?90% calcium carbonate) on an oceanic atoll system in the Coral Sea. The biomass measured

Edward A. Drew

1983-01-01

360

Nocturnal relocation of adult and juvenile coral reef fishes in response to reef noise  

Microsoft Academic Search

Juvenile and adult reef fishes often undergo migration, ontogenic habitat shifts, and nocturnal foraging movements. The orientation\\u000a cues used for these behaviours are largely unknown. In this study, the use of sound as an orientation cue guiding the nocturnal\\u000a movements of adult and juvenile reef fishes at Lizard Island, Great Barrier Reef was examined. The first experiment compared\\u000a the movements

S. D. Simpson; A. Jeffs; J. C. Montgomery; R. D. McCauley; M. G. Meekan

2008-01-01

361

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

Microsoft Academic Search

We examined the importance of picoplankton and virioplankton to reef trophodynamics at Ningaloo Reef, (north-western Australia),\\u000a 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\\u000a reef and into the lagoon.

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

2011-01-01

362

Climate change and coral reef bleaching: An ecological assessment of long-term impacts, recovery trends and future outlook  

NASA Astrophysics Data System (ADS)

Since the early 1980s, episodes of coral reef bleaching and mortality, due primarily to climate-induced ocean warming, have occurred almost annually in one or more of the world's tropical or subtropical seas. Bleaching is episodic, with the most severe events typically accompanying coupled ocean-atmosphere phenomena, such as the El Niño-Southern Oscillation (ENSO), which result in sustained regional elevations of ocean temperature. Using this extended dataset (25+ years), we review the short- and long-term ecological impacts of coral bleaching on reef ecosystems, and quantitatively synthesize recovery data worldwide. Bleaching episodes have resulted in catastrophic loss of coral cover in some locations, and have changed coral community structure in many others, with a potentially critical influence on the maintenance of biodiversity in the marine tropics. Bleaching has also set the stage for other declines in reef health, such as increases in coral diseases, the breakdown of reef framework by bioeroders, and the loss of critical habitat for associated reef fishes and other biota. Secondary ecological effects, such as the concentration of predators on remnant surviving coral populations, have also accelerated the pace of decline in some areas. Although bleaching severity and recovery have been variable across all spatial scales, some reefs have experienced relatively rapid recovery from severe bleaching impacts. There has been a significant overall recovery of coral cover in the Indian Ocean, where many reefs were devastated by a single large bleaching event in 1998. In contrast, coral cover on western Atlantic reefs has generally continued to decline in response to multiple smaller bleaching events and a diverse set of chronic secondary stressors. No clear trends are apparent in the eastern Pacific, the central-southern-western Pacific or the Arabian Gulf, where some reefs are recovering and others are not. The majority of survivors and new recruits on regenerating and recovering coral reefs have originated from broadcast spawning taxa with a potential for asexual growth, relatively long distance dispersal, successful settlement, rapid growth and a capacity for framework construction. Whether or not affected reefs can continue to function as before will depend on: (1) how much coral cover is lost, and which species are locally extirpated; (2) the ability of remnant and recovering coral communities to adapt or acclimatize to higher temperatures and other climatic factors such as reductions in aragonite saturation state; (3) the changing balance between reef accumulation and bioerosion; and (4) our ability to maintain ecosystem resilience by restoring healthy levels of herbivory, macroalgal cover, and coral recruitment. Bleaching disturbances are likely to become a chronic stress in many reef areas in the coming decades, and coral communities, if they cannot recover quickly enough, are likely to be reduced to their most hardy or adaptable constituents. Some degraded reefs may already be approaching this ecological asymptote, although to date there have not been any global extinctions of individual coral species as a result of bleaching events. Since human populations inhabiting tropical coastal areas derive great value from coral reefs, the degradation of these ecosystems as a result of coral bleaching and its associated impacts is of considerable societal, as well as biological concern. Coral reef conservation strategies now recognize climate change as a principal threat, and are engaged in efforts to allocate conservation activity according to geographic-, taxonomic-, and habitat-specific priorities to maximize coral reef survival. Efforts to forecast and monitor bleaching, involving both remote sensed observations and coupled ocean-atmosphere climate models, are also underway. In addition to these efforts, attempts to minimize and mitigate bleaching impacts on reefs are immediately required. If significant reductions in greenhouse gas emissions can be achieved within the next two to three decades, maximizing coral surv

Baker, Andrew C.; Glynn, Peter W.; Riegl, Bernhard

2008-12-01

363

Could some coral reefs become sponge reefs as our climate changes?  

PubMed

Coral reefs across the world have been seriously degraded and have a bleak future in response to predicted global warming and ocean acidification (OA). However, this is not the first time that biocalcifying organisms, including corals, have faced the threat of extinction. The end-Triassic mass extinction (200 million years ago) was the most severe biotic crisis experienced by modern marine invertebrates, which selected against biocalcifiers; this was followed by the proliferation of another invertebrate group, sponges. The duration of this sponge-dominated period far surpasses that of alternative stable-ecosystem or phase-shift states reported on modern day coral reefs and, as such, a shift to sponge-dominated reefs warrants serious consideration as one future trajectory of coral reefs. We hypothesise that some coral reefs of today may become sponge reefs in the future, as sponges and corals respond differently to changing ocean chemistry and environmental conditions. To support this hypothesis, we discuss: (i) the presence of sponge reefs in the geological record; (ii) reported shifts from coral- to sponge-dominated systems; and (iii) direct and indirect responses of the sponge holobiont and its constituent parts (host and symbionts) to changes in temperature and pH. Based on this evidence, we propose that sponges may be one group to benefit from projected climate change and ocean acidification scenarios, and that increased sponge abundance represents a possible future trajectory for some coral reefs, which would have important implications for overall reef functioning. PMID:23553821

Bell, James J; Davy, Simon K; Jones, Timothy; Taylor, Michael W; Webster, Nicole S

2013-09-01

364

Reef fish and habitat relationships in a Caribbean seascape: the importance of reef context  

NASA Astrophysics Data System (ADS)

Marine protected area (MPA) effectiveness is contingent on understanding key ecological patterns and processes at appropriate spatial scales and may depend upon maintaining critical linkages among essential habitat patches to conserve reef-fish communities. Hypotheses were tested to investigate the importance of habitat linkages in the US Virgin Islands. As expected, reef context (the spatial pattern of surrounding habitat patches) was a strong predictor of reef fish assemblage structure. Specific relationships were functionally consistent with the ecology of the fishes of interest. For example, reefs with large amounts of seagrass nearby harbored the greatest numerical abundance of fishes, particularly mobile invertebrate feeders and the exploited fish families of Haemulidae (grunts) and Lutjanidae (snappers). Species richness for the entire fish community and within these fish groups was also strongly associated with reef context. Furthermore, reef fish mobility influenced how fishes related to reef context. Fish-habitat relationships were detected as far as 1 km from study reefs, suggesting that fish movements result in habitat encounter rates that may influence their patterns of distribution. Consequently, functional habitat connectivity of habitat patches appears important in structuring reef-fish assemblages, and suggests that landscape-scale metrics may provide insights useful to managers in the design of MPAs.

Grober-Dunsmore, R.; Frazer, T. K.; Lindberg, W. J.; Beets, J.

2007-03-01

365

Florida's Fragile Reefs: What's Happening to this Underwater World?  

NSDL National Science Digital Library

This BioBulletin Web site takes an in-depth look at coral reefs and how they are affected by human activities: everything from agricultural pollution and ship grounding to snorkeling and overfishing. With Florida's fragile reefs as the backdrop, the site includes text, videos and photographs. The Introduction explains the fragility of these the massive underwater structures. What Are Reefs? discusses how these "rain forests of the sea" support an even more astonishing variety of life. Reefs in Hot Water presents the factors behind why reefs around the world are declining at an unprecedented rate. Monitoring a Reef at Risk covers the Florida Keys Coral Reef Monitoring Project, funded by the Environmental Protection Agency. Treating Reefs Right lists ways in which boaters, fishermen, swimmers, and divers can do their part to protect coral reefs.

366

Coral reefs of the Mascarenes, Western Indian Ocean.  

PubMed

The reefs of the Mascarenes differ in structure and stage of development. Mauritius is the oldest island, bound by a discontinuous fringing reef and small barrier reef, with large lagoon patch reefs. Rodrigues has nearly continuous fringing reefs bounding an extensive lagoon with deep channels and few patch reefs. Reunion, the youngest island, has short stretches of narrow fringing reefs along southwestern coasts. The islets of St Brandon are bound to the east by an extensive arc of fringing reef. Reef mapping of the Mascarenes using satellite imagery provides an estimate of 705 km2 of shallow reef habitats. These areas have been modified over geological time by changes in sea level, ocean-atmosphere disturbances and biological and chemical forcing. Further modification has resulted from historical changes in land-use patterns. Recent economic development has placed many of these reefs at risk from anthropogenic impact. The reefs of the Mascarenes have escaped mass mortality from bleaching to date, which increases their conservation significance within the wider Indian Ocean. The reefs are poorly protected. A case study shows how a geographic information system incorporating reef-habitat maps can help formulate and demonstrate Marine Protected Area boundaries. PMID:15598634

Turner, John; Klaus, Rebecca

2005-01-15

367

MANGROVE-DERIVED NUTRIENTS AND CORAL REEFS  

EPA Science Inventory

Understanding the consequences of the declining global cover of mangroves due to anthropogenic disturbance necessitates consideration of how mangrove-derived nutrients contribute to threatened coral reef systems. We sampled potential sources of organic matter and a suite of sessi...

368

Ocean acidification impairs vermetid reef recruitment  

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

369

Explore coral reefs around the world  

NSDL National Science Digital Library

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.

TERC

370

Ocean acidification impairs vermetid reef recruitment.  

PubMed

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

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

2014-01-01

371

Reef Ecosystem Services and Decision Support Database  

EPA Science Inventory

This scientific and management information database utilizes systems thinking to describe the linkages between decisions, human activities, and provisioning of reef ecosystem goods and services. This database provides: (1) Hierarchy of related topics - Click on topics to navigat...

372

Extinction vulnerability of coral reef fishes.  

PubMed

With rapidly increasing rates of contemporary extinction, predicting extinction vulnerability and identifying how multiple stressors drive non-random species loss have become key challenges in ecology. These assessments are crucial for avoiding the loss of key functional groups that sustain ecosystem processes and services. We developed a novel predictive framework of species extinction vulnerability and applied it to coral reef fishes. Although relatively few coral reef fishes are at risk of global extinction from climate disturbances, a negative convex relationship between fish species locally vulnerable to climate change vs. fisheries exploitation indicates that the entire community is vulnerable on the many reefs where both stressors co-occur. Fishes involved in maintaining key ecosystem functions are more at risk from fishing than climate disturbances. This finding is encouraging as local and regional commitment to fisheries management action can maintain reef ecosystem functions pending progress towards the more complex global problem of stabilizing the climate. PMID:21320260

Graham, Nicholas A J; Chabanet, Pascale; Evans, Richard D; Jennings, Simon; Letourneur, Yves; Aaron Macneil, M; McClanahan, Tim R; Ohman, Marcus C; Polunin, Nicholas V C; Wilson, Shaun K

2011-04-01

373

40 CFR 230.44 - Coral reefs.  

Code of Federal Regulations, 2010 CFR

...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...

2010-07-01

374

40 CFR 230.44 - Coral reefs.  

Code of Federal Regulations, 2012 CFR

...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...

2012-07-01

375

40 CFR 230.44 - Coral reefs.  

Code of Federal Regulations, 2013 CFR

...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...

2013-07-01

376

40 CFR 230.44 - Coral reefs.  

...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...

2014-07-01

377

A critical review of environmental management of the 'not so Great' Barrier Reef  

NASA Astrophysics Data System (ADS)

Recent estimates put average coral cover across the Great Barrier Reef (GBR) at about 20-30%. This is estimated to be a large reduction since the 1960s. The Great Barrier Reef Marine Park Act was enacted in 1975 and the Great Barrier Reef Marine Park Authority (GBRMPA) set up shortly afterwards. So the question is: why has coral cover continued to decline when the GBR is being managed with a management regime often recognised as 'the best managed coral reef system in the world', based on a strong science-for-management ethic. The stressors which are known to be most responsible for the loss of coral cover (and general 'reef health') are terrestrial pollution including the link to outbreaks of crown of thorns starfish, fishing impacts and climate change. These have been established through a long and intensive research effort over the last 30 years. However the management response of the GBRMPA after 1975, while based on a strong science-for-management program, did not concentrate on these issues but instead on managing access through zoning with restrictions on fishing in very limited areas and tourism management. Significant action on fishing, including trawling, did not occur until the Trawl Management Plan of 2000 and the rezoning of the GBR Marine Park in 2004. Effective action on terrestrial pollution did not occur until the Australian Government Reef Rescue initiative which commenced in 2008. Effective action on climate change has yet to begin either nationally or globally. Thus it is not surprising that coral cover on the GBR has reduced to values similar to those seen in other coral reef areas in the world such as Indonesia and the Philippines. Science has always required long periods to acquire sufficient evidence to drive management action and hence there is a considerable time lag between the establishment of scientific evidence and the introduction of effective management. It can still be credibly claimed that the GBR is the best managed coral reef system in the world but it must be realised that this is a relative assessment against other reef systems and management regimes and not an absolute claim for effective management.

Brodie, Jon; Waterhouse, Jane

2012-06-01

378

Paleobiologic and paleoenvironmental context of coral-bearing Early Cambrian reefs: Implications for Phanerozoic reef development  

NASA Astrophysics Data System (ADS)

Early Cambrian corals from South Australia have been found within fossil reefs of unusual biological and paleoecological composition. The framework of these reefs is composed of a diverse assemblage of calcareous sponges (e.g., archaeocyaths and sphinctozoans), calci-microbes, and at least two species of coral-like organisms, one of which is first reported herein and bears similarities to younger Paleozoic tabulate corals. Complex growth interactions occur among these organisms, suggesting that space was a limiting factor in Early Cambrian reef ecosystems, as it is today in modern scleractinian reefs. In striking contrast to most Early Cambrian archaeocyath-calcimicrobe reefs, these South Australian reefs flourished within energetic, mixed silici-clastic-carbonate shallow-marine environments along the margins of arid, coarse-grained, sea-marginal alluvial fans. The implications of these coral-bearing reefs are multifold. First, their existence not only extends the range of tabulatelike corals to the Botomian (middle Early Cambrian), but it adds an additional clade of participants to the Early Cambrian metazoan radiation event. Second, the existence of Botomian-aged skeletonized colonial cnidarians necessitates an earliest Cambrian or Neoproterozoic ancestor for the group. Third, the presence of tabulatelike corals and their involvement in reef building prior to the Toyonian extinction (late Early Cambrian) challenges hypotheses (e.g., lack of a suitable reef builder after the extinction of archaeocyaths until the Ordovician) used to explain the paucity of Middle and Late Cambrian reefs worldwide. The presence of these corals on sea-marginal fans contradicts the perception that early reefs were restricted to low-energy, predominantly carbonate subtidal environments.

Savarese, Michael; Mount, Jeffrey F.; E., James; Bucklin, Louis

1993-10-01

379

Comparing the Invasibility of Experimental “Reefs” with Field Observations of Natural Reefs and Artificial Structures  

PubMed Central

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

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

2012-01-01

380

Hurricane Allen's Impact on Jamaican Coral Reefs.  

PubMed

Coral reefs of north Jamaica, normally sheltered, were severely damaged by Hurricane Allen, the strongest Caribbean hurricane of this century. Immediate studies were made at Discovery Bay, where reef populations were already known in some detail. Data are presented to show how damage varied with the position and orientation of the substraturn and with the shape, size, and mechanical properties of exposed organisms. Data collected over succeeding weeks showed striking differences in the ability of organisms to heal and survive. PMID:17744383

Woodley, J D; Chornesky, E A; Clifford, P A; Jackson, J B; Kaufman, L S; Knowlton, N; Lang, J C; Pearson, M P; Porter, J W; Rooney, M C; Rylaarsdam, K W; Tunnicliffe, V J; Wahle, C M; Wulff, J L; Curtis, A S; Dallmeyer, M D; Jupp, B P; Koehl, M A; Neigel, J; Sides, E M

1981-11-13

381

Dynamic fragility of oceanic coral reef ecosystems  

Microsoft Academic Search

As one of the most diverse and productive ecosystems known, and one of the first ecosystems to exhibit major climate-warming impacts (coral bleaching), coral reefs have drawn much scientific attention to what may prove to be their Achilles heel, the thermal sensitivity of reef-building corals. Here we show that climate change-driven loss of live coral, and ultimately structural complexity, in

Nicholas A. J. Graham; Shaun K. Wilson; Simon Jennings; Nicholas V. C. Polunin; Jude P. Bijoux; Jan Robinson

2006-01-01

382

Rapid vertical accretion on a `young' shore-detached turbid zone reef: Offshore Paluma Shoals, central Great Barrier Reef, Australia  

NASA Astrophysics Data System (ADS)

We report on the age structure and net accretion rates determined for an open water turbid zone reef, known as Offshore Paluma Shoals, located on the inner central Great Barrier Reef. Twenty-eight radiocarbon dates from 5 cores through the reef structure indicate that this reef began growing ~1,700 years ago and that net vertical accretion through the main phase of reef development was rapid (averaging 7.8 mm yr-1), this despite the reef growing in highly turbid waters. The most rapid growth phases coincided with the accumulation of mud-rich terrigenoclastic sediments within the reef fabric. The study emphasises the capacity of turbid zone reefs to vertically accrete at rates matching or exceeding many clear water reefs despite seemingly detrimental water quality conditions.

Perry, C. T.; Smithers, S. G.; Gulliver, P.

2013-12-01

383

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

NASA Astrophysics Data System (ADS)

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.

Barrett, Samuel; Webster, Jody

2013-04-01

384

Using virtual reality for science mission planning: A Mars Pathfinder case  

Microsoft Academic Search

NASA's Mars Pathfinder Project requires a Ground Data System (GDS) that supports both engineering and scientific payloads with reduced mission operations staffing, and short planning schedules. Also, successful surface operation of the lander camera requires efficient mission planning and accurate pointing of the camera. To meet these challenges, a new software strategy that integrates virtual reality technology with existing navigational

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

1994-01-01

385

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

Microsoft Academic Search

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

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

386

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

Microsoft Academic Search

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

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

387

Axonal Pathfinding D Mortimer and G J Goodhill, The University of  

E-print Network

understanding of the princi- ples and mechanisms underlying axon pathfinding has both clinical and broader practical importance. From a clinical perspective, our ability to treat or prevent some neurological defects will be improved by a better under- standing of how axon guidance can fail. Furthermore, the regeneration

Goodhill, Geoffrey J.

388

Calibration of the Mars Pathfinder alpha proton X-ray spectrometer  

NASA Astrophysics Data System (ADS)

The chemical compositions of Martian rocks and soils examined with the alpha proton X-ray spectrometer (APXS) during the Mars Pathfinder 1997 lander mission were not previously fully determined. Preliminary chemical results included major element abundances determined by the incomplete calibration of the X-ray mode. The data collected from the alpha and proton detectors were not previously analyzed due to significant atmospheric contributions to the spectra. The backup instrument of the Pathfinder alpha proton X-ray spectrometer flight instrument has been used to complete the instrument calibration under simulated Martian conditions at the University of Chicago. An APXS instrument has been used to create a Pathfinder calibration library to test the accuracy of all three instrument modes under simulated Martian conditions. This calibration library has been tested on a number of geologic standards. We have also corrected for instrument differences between the laboratory and flight units. Significant chemical results, somewhat different from those initially reported by Rieder et al. [1997a] and by Wänke et al. [2001], are reported by Foley et al. [2003] as a result of this reanalysis of the Pathfinder APXS data.

Foley, C. Nicole; Economou, Thanasis E.; Clayton, Robert N.; Dietrich, William

2003-11-01

389

Lookahead Pathology in Real-Time Path-Finding Mitja Lustrek  

E-print Network

Lookahead Pathology in Real-Time Path-Finding Mitja Lustrek Jozef Stefan Institute Department due to the incompleteness of their search and inaccu- racies in the heuristic. Lookahead pathologies research on lookahead pathologies has focused on minimax search and small syn- thetic examples in single

LuÂ?trek, Mitja

390

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

E-print Network

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

LuÂ?trek, Mitja

391

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

E-print Network

Thinking Too Much: Pathology in Pathfinding Mitja Lustrek 1 and Vadim Bulitko 2 Abstract. Large and inaccuracies in the heuristic. Lookahead pathology occurs when deeper search results in worse actions. Over examples in single-agent search. This paper conducts a large-scale investigation of the pathology in real

LuÂ?trek, Mitja

392

The atmosphere structure and meteorology instrument on the Mars Pathfinder lander  

Microsoft Academic Search

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

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

393

Morning Martian Atmospheric Temperature Gradients and Fluctuations Observed by Mars Pathfinder  

NASA Technical Reports Server (NTRS)

We have studied the most prominent atmospheric temperature fluctuations observed during Martian mornings by Mars Pathfinder and have concluded, based on comparisons with wind directions, that they appear to be a result of atmospheric heating associated with the Lander spacecraft. Also, we have examined the morning surface layer temperature lapse rates, which are found to decrease as autumn approaches at the Pathfinder location, and which have mean (and median) values as large as 7.3 K/m in the earlier portions of the Pathfinder landed mission. It is plausible that brief isolated periods with gradients twice as steep are associated with atmospheric heating adjacent to Lander air bag material. In addition, we have calculated the gradient with height of the structure function obtained with Mars Pathfinder, for Mars' atmospheric temperatures measured within about 1.3 m from the surface, assuming a power law dependence, and have found that these gradients superficially resemble those reported for the upper region of the terrestrial stable boundary layer.

Mihalov, John D.; Haberle, R. M.; Murphy, J. R.; Seiff, A.; Wilson, G. R.

1999-01-01

394

Mineralogic and compositional properties of Martian soil and dust: Results from Mars Pathfinder  

Microsoft Academic Search

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

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

2000-01-01

395

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

PubMed

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

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

2014-09-21

396

Characterization of the Martian Surface Deposits by the Mars Pathfinder Rover, Sojourner  

NASA Technical Reports Server (NTRS)

Sojourner, the pathfinder rover, has discovered pebbles on the surface and in rocks that may be semidentary-not volcanic-in origin. Surface pebbles may have been rounded by Ares Flood Waters or liberated by weathering of sedimentary rocks called conglomerates.

Matijevic, J.

1997-01-01

397

Global Climate Change Pathfinder: A Guide to Information Resources. Second Edition.  

ERIC Educational Resources Information Center

This pathfinder is a guide to scientific and technical aspects of global climate change including meteorological and climatological aspects; biological, agricultural, and public policy implications; and the chemical processes involved. Sources are arranged by type of publication and include: (1) 10 reference sources; (2) 12 bibliographies; (3) 44…

Pintozzi, Chestalene; Jones, Douglas E.

398

Monitoring of coral reefs on Ishigaki Island in Japan using multitemporal remote sensing data  

Microsoft Academic Search

In recent years environmental problems in the coral reefs attract both scientific and social attentions. However, most coral reefs have few maps showing the reef topography and the distributions of various benthic habitats in the reef. Satellite remote sensing can be used for coral reef mapping because satellites can observe the reefs scattered in tropical oceans in a short time

Tsuneo Matsunaga; Akira Hoyano; Yosei Mizukami

2001-01-01

399

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

Microsoft Academic Search

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

J. F. Marshall; P. J. Davies

1982-01-01

400

Philippine Coral Reefs Under Threat: The Economic Losses Caused by Reef Destruction  

Microsoft Academic Search

In the Philippines, coral reef fisheries provide livelihood for more than a million small-scale fishers who contribute almost US$ 1 billion annually to the country’s economy. The rapidly growing population needs increasing amounts of fish and other marine organisms. However, overfishing, destructive fishing methods and sedimentation have damaged or destroyed many reef areas. Fish catches have fallen well below the

Alan T White; Helge P Vogt; Tijen Arin

2000-01-01

401

Reef corals of Johnston Atoll: one of the world's most isolated reefs  

Microsoft Academic Search

Johnston Atoll lies 800 km southwest of the nearest reefs of Hawaii and over 1,500 km from other shallow reefs to the south and west. Only 33 species and 16 genera and subgenera of shallow water stony corals have been reported from the atoll. Endemic species are absent despite Johnston's great age and favorable environment. With few exceptions, only species

James E. Maragos; Paul L. Jokiel

1986-01-01

402

Reef size and isolation determine the temporal stability of coral reef fish populations.  

PubMed

Temporal variance in species abundance, a potential driver of extinction, is linked to mean abundance through Taylor's power law, the empirical observation of a linear log-log relationship with a slope between 1 and 2 for most species. Here we test the idea that the slope of Taylor's power law can vary both among species and spatially as a function of habitat area and isolation. We used the world's most extensive database of coral reef fish communities comprising a 15-year series of fish abundances on 43 reefs of Australia's Great Barrier Reef. Greater temporal variances were observed at small and isolated reefs, and lower variances at large and connected ones. The combination of reef area and isolation was associated with an even greater effect on temporal variances, indicating strong empirical support for the idea that populations on small and isolated reefs will succumb more frequently to local extinction via higher temporal variability, resulting in lower resilience at the community level. Based on these relationships, we constructed a regional predictive map of the dynamic fragility of coral reef fish assemblages on the Great Barrier Reef. PMID:21141175

Mellin, Camille; Huchery, Cindy; Caley, M Julian; Meekan, Mark G; Bradshaw, Corey J A

2010-11-01

403

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

404

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

USGS Publications Warehouse

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.

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

405

The Structure of Mediterranean Rocky Reef Ecosystems across Environmental and Human Gradients, and Conservation Implications  

PubMed Central

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. PMID:22393445

Sala, Enric; Ballesteros, Enric; Dendrinos, Panagiotis; Di Franco, Antonio; Ferretti, Francesco; Foley, David; Fraschetti, Simonetta; Friedlander, Alan; Garrabou, Joaquim; Güçlüsoy, 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

406

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

PubMed Central

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

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

2013-01-01

407

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

PubMed Central

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

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

2013-01-01

408

Habitat degradation is threatening reef replenishment by making fish fearless.  

PubMed

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

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

2014-02-01

409

12. Photo copy of drawing, May 5, 1930. PENFIELD REEF ...  

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

12. Photo copy of drawing, May 5, 1930. PENFIELD REEF L/S MODERNIZATION. Drawing no. NY-1393, U.S. Coast GUard Civil Engineering Unit, Warwick, Rhode Island. - Penfield Reef Lighthouse, Long Island Sound, Bridgeport, Fairfield County, CT

410

Recent and relict topography of Boo Bee patch reef, Belize  

USGS Publications Warehouse

Five core borings were taken on and around Boo Bee Patch Reef to better understand the origin of such shelf lagoon reefs. The cores reveal 4 stages of development: (1) subaerial exposure of a Pleistocene "high" having about 8 meters of relief, possibly a Pleistocene patch reef; (2) deposition of peat and impermeable terrigenous clay 3 meters thick around the high; (3) initiation of carbonate sediment production by corals and algae on the remaining 5 meters of hard Pleistocene topography and carbonate mud on the surrounding terrigenous clay; and (4) accelerated organic accumulation on the patch reef. Estimates of patch reef sedimentation rates (1.6 m/1000 years) are 3 to 4 times greater than off-reef sedimentation rates (0.4-0.5 m/1000 years). During periods of Pleistocene sedimentation on the Belize shelf, lagoon patch reefs may have grown above one another, stacking up to form reef accumulation of considerable thickness.

Halley, R.B.; Shinn, E.A.; Hudson, J.H.; Lidz, B.

1977-01-01

411

Coral reef formation theory may apply to oil, gas exploration  

SciTech Connect

This paper reports a coral reef formation theory that has implications for hydrocarbon exploration. The theory states that many coral reefs and carbonate buildups from at and are dependent upon nutrient rich fluids seeping through the seabed.

Not Available

1990-12-10

412

A Quick Guide to Southeast Florida's Coral Reefs  

E-print Network

and reproduce. Reefs provide safe havens for spectacular forms of marine life. Unfortunately, reefs dredging, beach nourishment, coastal construction, vessel groundings and injuries from pipelines, cables, anchors, chains and marine debris. Overfishing has disrupted food webs and has been implicated

413

Checklist of Fishes from Madagascar Reef, Campeche Bank, México  

PubMed Central

Abstract This study presents the first list of fish species from Madagascar Reef, Campeche Bank, Gulf of México. Field surveys and literature review identified 54 species belonging to 8 orders, 30 families and 43 genera, comprising both conspicuous and cryptic fishes. Species richness was lower at this reef site compared to reefs in the Mexican Caribbean, Veracruz or Tuxpan, but was similar to other reefs in the same region. Species composition was a mixture of species present in all the reef systems of the Mexican Atlantic. Hypoplectrus ecosur was recorded here for the first time in the Gulf of Mexico, Mycteroperca microlepis, Equetus lanceolatus and Chaetodipterus faber were new records for the reefs of the Campeche Bank, Elacatinus xanthiprora was recorded for the second time in Mexico and expanded its known distribution westwards from Alacranes Reef and Sanopus reticulatus, endemic of the Yucatan state, was recorded here for the first time on a reef. PMID:24891834

2014-01-01

414

The National Oceanic and Atmospheric Administrations 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.

2007-12-12

415

Hydrodynamic Regimes Affect Coral Reef Resilience to Ocean Acidification  

NASA Astrophysics Data System (ADS)

Caribbean reefs hold tremendous value as sources of food, income, coastal protection, in addition to their cultural significance. Recently, studies showed that Caribbean reef growth has been surpassed in places by excessive rates of erosion due to climate change. The rates of coral reef response to ocean pH changes and warming and the implications for ecosystem resilience remain largely unknown. One way to investigate the potential structural resilience of reefs to climate change is to measure the physical oceanographic conditions in the area. Determining the hydrodynamic regimes and residence time of water in a particular reef environment is crucial to understanding the rates of future warming and acidification a reef site would experience. Our work on Pacific Islands' hydrodynamics - Central Equatorial Pacific, Great Barrier Reef, and Western Pacific -- would be of interest to Caribbean physical oceanographers and coral reef scientists. We use a combination of Acoustic Doppler Current Profilers, Acoustic Doppler Velocimeters, temperature and salinity sensors, and pressure sensors to characterize reef hydrodynamic regimes. Our work indicates that shallower, more protected reef habitats are characterized by longer residence times, their biological signals are strongly tidally modulated, essentially subjecting such habitats to higher rates of warming and acidification in the future. Reef crest environments and fore reef habitats, on the other hand, are well-mixed with open-ocean water. The hydrodynamic regimes there condition such reef sites to more attenuated temperature and pH ranges, conditions more typical of the open ocean. Our work suggests that investigating the geomorphology and resulting localized hydrodynamics in a reef area can provide insights into the relative rates at which a reef could resist or succumb to impacts of ocean acidification. Such information for different reef islands, in the Pacific or Caribbean basins, could provide helpful insights into predictions for economic losses to coastal communities due to climate change.

Teneva, L. T.; Dunbar, R. B.; Koseff, J. R.; Fleischfresser, J. D.; Koweek, D.

2013-05-01

416

Exploring Drowned Reefs on Gardner Pinnacles  

NASA Astrophysics Data System (ADS)

Gardner Pinnacles (GP), located in the Northwest Hawaiian Islands within Papah?naumoku?kea Marine National Monument, is one of the largest volcanic structures in the entire Hawaiian-Emperor chain. In Oct. 2011, the R/V Ka'imikai-o-Kanaloa mapped and the Pisces IV submersible explored the GP during 7 dives, mainly on drowned reef terraces. New multibeam bathymetric data from the cruise, combined with pre-existing multibeam data mostly collected during transits across the structure, show at least 4 separate volcanoes partially surrounded by several Miocene to Pleistocene drowned coral reefs with extensive lagoons, with the largest volcano surmounted by an active carbonate platform. Large landslides modify the flanks, and the eastern flank is incised by submarine canyons. Seven submersible dives explored and sampled mainly the drowned reef structures. The largest reef complex is on the NW flank above the main break-in-slope, and is a barrier reef surrounding extensive lagoon deposits with complex channel structures. Similar wide lagoons with deep channels parallel to the outer reef terraces are present elsewhere on GP, but unusual elsewhere in the Hawaiian Islands. Seven corals, coralline algae, and echinoid spines from dive P4-266 on that NW edge of GP from 1268-1637 m depth yield a tight age cluster based on Sr-isotopes calibrated to seawater that range from 15.51 to 15.98 Ma, and average 15.76 Ma. Five ages of echinoid spines, mollusk shells, and large foraminfers from dive P4-255 on the SW edge of GP from 1538-1558 m depth range from 14.88 to 15.10 Ma, and average 14.98 Ma. Three ages of corals and coralline algae from dive P4-253 on the SE edge of GP at 1955 m depth range from 12.35 and 12.7 Ma, and average 12.57 Ma. The ages of these reefs indicate when volcanic activity waned and reef deposits could accumulate without constant burial by lava flows; the nearly 3.2 Ma range in reef ages from the flanks of GP suggest that volcanic activity at GP spanned a similar time period. The NW barrier reef is a 310-m-tall ridge surmounted by 140-m pinnacles, consistent with rapid upward growth during the Middle Miocene Climatic Optimum. With two exceptions, all carbonate samples collected from <910 m and a few from deeper terraces, yielded Pleistocene or younger ages. The Pleistocene aged samples on such deep reefs suggest extensive downslope transport of reef debris. Lava samples collected during the dives include tholeiitic shield-stage lavas and several rounded postshield-stage hawaiite cobbles in volcanic/carbonate beach sandstone. Published K-Ar age of volcanic rocks from GP of 12.3±1.0 Ma (Garcia et al., 1987) is inconsistent with the older ages of the overlying reefs. New Ar-Ar age data of samples from the dive program will be presented.

Clague, D. A.; Paduan, J. B.; Braga, J. C.; Humphrey, C.; Hinestrosa, G.; Fullagar, P. D.

2012-12-01

417

The actin-binding protein UNC-115 is an effector of Rac signaling during axon pathfinding in C-elegans  

E-print Network

Rac GTPases control cell shape by regulating downstream effectors that influence the actin cytoskeleton. UNC-115, a putative actin-binding protein similar to human abLIM/limatin, has previously been implicated in axon pathfinding. We have discovered...

Struckhoff, Eric Charles; Lundquist, Erik A.

2003-02-01

418

Correspondence and Least Squares Analyses of Soil and Rock Compositions for the Viking Lander 1 and Pathfinder Sites  

NASA Technical Reports Server (NTRS)

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.

Larsen, K. W.; Arvidson, R. E.; Jolliff, B. L.; Clark, B. C.

2000-01-01

419

59 FR- Reef Fish Fishery of the Gulf of Mexico  

Federal Register 2010, 2011, 2012, 2013

...0648-AE58 Reef Fish Fishery of the Gulf of Mexico AGENCY: National Marine Fisheries...the Reef Fish Resources of the Gulf of Mexico (FMP) and to make other changes...additional participants in the Gulf of Mexico reef fish fishery who may use...

1994-01-07

420

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 ...

421

FINAL REPORT to the Great Barrier Reef Marine Park Authority  

E-print Network

FINAL REPORT to the Great Barrier Reef Marine Park Authority Seasonal distribution of the dugong in the southern Great Barrier Reef Marine Park. Helene Marsh and Helen Penrose #12;i Table of Contents Executive Sandy Strait DPA. 38 39 #12;1 Seasonal distribution of the dugong in the southern Great Barrier Reef

Marsh, Helene

422

Managing the Great Barrier Reef World Heritage Area  

E-print Network

SESSION 7 Managing the Great Barrier Reef World Heritage Area Chair: Ian McPhail Rapporteur: Helene (abstract only) The changing roles of aboriginal people in the management of the Great Barrier Reef. Noel Pearson and A Leibler- (presented by A Tanner, abstract only) State of the Great Barrier Reef World

Marsh, Helene

423

Impact of micropredatory gnathiid isopods on young coral reef fishes  

E-print Network

for the hypothesis that reef-based A. polyacanthus juveniles are better adapted to gnathiid attack than fishREPORT Impact of micropredatory gnathiid isopods on young coral reef fishes A. S. Grutter Ã? J. L-history stages of coral reef fish, and whether this varies between fish with and without a pelagic phase

Grutter, Alexandra "Lexa"

424

Report Evaluates Importance of Coral Reefs and Mangroves  

Microsoft Academic Search

Thirty percent of the world's coral reefs are seriously damaged, and possibly no pristine reefs remain, according to a 24 January report by the World Conservation Monitoring Centre of the United Nations Environment Programme (UNEP) issued in the wake of the 26 December 2004 Indian Ocean tsunami. ``The Indian Ocean tsunami brought a lot of attention to coral reefs and

Mohi Kumar

2006-01-01

425

Experimental Assessment of Coral Reef Rehabilitation Following Blast Fishing  

Microsoft Academic Search

Illegal fishing with explosives has damaged coral reefs throughout Southeast Asia. In addition to killing fish and other organisms, the blasts shatter coral skeletons, leaving fields of broken rubble that shift in the current, abrading or burying new coral recruits, and thereby slowing or preventing reef recovery. Successful restoration and rehabilitation efforts can contribute to coral reef conservation. We used

HELEN E. FOX; PETER J. MOUS; JOS S. PET; ANDREAS H. MULJADI; ROY L. CALDWELL

2005-01-01

426

CARBON TURNOVER AND ACCUMULu..TION BY CORAL REEFS  

E-print Network

CARBON TURNOVER AND ACCUMULu..TION BY CORAL REEFS A DISSERTATION SUBMITTED TO THE GRADUATE GIVIS the other sites. There is great operational unifor~ity in coral reef metabolism apparentiy re- gardless ism is great, probably at all latitudes at which coral reefs are found. Unperturbed systems

Luther, Douglas S.

427

Explore Online: Question-Driven Coral-Reef Monitoring  

E-print Network

Explore Online: Question-Driven Coral-Reef Monitoring Agriculture and Greenhouse Gas Emissions / Vol. 63 No. 4 · BioScience 297 Progress and Perspectives on Question-Driven Coral-Reef Monitoring Peter Houk and robert van Woesik Despite a steady growth in coral-reef monitoring efforts

Mcilwain, Jenny

428

-Congressional Policy Brief -United States Coral Reef Task Force  

E-print Network

- Congressional Policy Brief - United States Coral Reef Task Force "NOAA, on behalf of the Department of Commerce, is honored to serve as Co-Chair of the U.S. Coral Reef Task Force, along and better understand our nation's valuable coral reef ecosystems." - Tim Keeney Deputy Assistant Secretary

429

Coral Reefs Under Rapid Climate Change and Ocean Acidification  

E-print Network

Coral Reefs Under Rapid Climate Change and Ocean Acidification O. Hoegh-Guldberg,1 * P. J. Mumby,2 carbonate accretion, with corals becoming increasingly rare on reef systems. The result will be less diverse, coral reefs have continued to deteriorate as a result of human in- fluences (3, 4). Rapid increases

Schweik, Charles M.

430

Climate Change, Human Impacts, and the Resilience of Coral Reefs  

E-print Network

Climate Change, Human Impacts, and the Resilience of Coral Reefs T. P. Hughes,1 * A. H. Baird,1 D. Rosen,13 J. Roughgarden14 The diversity, frequency, and scale of human impacts on coral reefs and temperature over the next 50 years exceed the conditions under which coral reefs have flourished over the past

Kleypas, Joanie

431

Watersheds and Coral Reefs: Conservation Science, Policy, and Implementation  

Microsoft Academic Search

Coral reefs worldwide are being degraded by human-induced disturbances, resulting in ecological, economic, and cultural losses. Runoff and sedimentation are among the greatest threats to the coastal reefs surrounding high islands and adjacent to continental landmasses. Existing scientific data identify the key stressors, synergisms, and outcomes at the coral reef ecosystem, community, and population levels. These data demonstrate that marine

ROBERT H. RICHMOND; TEINA RONGO; YIMNANG GOLBUU; STEVEN VICTOR; NOAH IDECHONG; GERRY DAVIS; WILLY KOSTKA; LEINSON NETH; MICHAEL HAMNETT; ERIC WOLANSKI

2007-01-01

432

Well-point sampling of reef interstitial water  

Microsoft Academic Search

A technique is described for collecting reef interstitial water using manually-driven well points. This method does not require the use of hydraulic drills, and eliminates the problems associated with the casing of boreholes. The technique allows collection of samples from discrete depths within reef frameworks, and produces samples unaffected by atmospheric or surface seawater contamination. Data from Checker Reef, Oahu,

Francis J. Sansone; Christine C. Andrews; Robert W. Buddemeier; Gordon W. Tribble

1988-01-01

433

The Diversity of Coral Reefs: What Are We Missing?  

Microsoft Academic Search

Tropical reefs shelter one quarter to one third of all marine species but one third of the coral species that construct reefs are now at risk of extinction. Because traditional methods for assessing reef diversity are extremely time consuming, taxonomic expertise for many groups is lacking, and marine organisms are thought to be less vulnerable to extinction, most discussions of

Laetitia Plaisance; M. Julian Caley; Russell E. Brainard; Nancy Knowlton; Peter Roopnarine

2011-01-01

434

Direct evaluation of macroalgal removal by herbivorous coral reef fishes  

Microsoft Academic Search

Few studies have examined the relative functional impacts of individual herbivorous fish species on coral reef ecosystem processes in the Indo-Pacific. This study assessed the potential grazing impact of individual species within an inshore herbivorous reef fish assemblage on the central Great Barrier Reef (GBR), by determining which fish species were able to remove particular macroalgal species. Transplanted multiple-choice algal

C. S. Mantyka; D. R. Bellwood

2007-01-01

435

Cementation of Upper Miocene reefs in western Mediterranean  

Microsoft Academic Search

Coral reefs in the western Mediterranean (southeast Spain, Balearic Island, northern Morocco, Sicily, and Italy) show a wide variety of cement types, ranging from completely tight, well-cemented, to poorly cemented reefs with most of the primary porosity still preserved. Cementation processes in those coral reefs appear to be controlled to a great extent by repeated changes of relative sea levels

M. Esteban; F. Calvet

1983-01-01

436

Funcitonal importance of Belize coral reefs, Wulff52 FUNCTIONAL IMPORTANCE OF BIODIVERSITY FOR CORAL REEFS OF BELIZE1  

E-print Network

Funcitonal importance of Belize coral reefs, Wulff52 FUNCTIONAL IMPORTANCE OF BIODIVERSITY FOR CORAL REEFS OF BELIZE1 Janie Wulff Department of Biological Science, Florida State University, Tallahassee, FL, USA; wulff@bio.fsu.edu ABSTRACT A thriving coral reef results from an intricate collaboration

Ronquist, Fredrik

437

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

...Coral and Reef Associated Plants and Invertebrates Fishery Management Plans of Puerto...Coral and Reef Associated Plants and Invertebrates for the U.S. Caribbean for review...coral and reef associated plants and invertebrates species. The 2011 Caribbean ACL...

2011-09-26

438

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

...Coral and Reef Associated Plants and Invertebrates Fishery Management Plans of Puerto...Corals and Reef Associated Plants and Invertebrates of Puerto Rico and the U.S. Virgin...corals and reef associated plants and invertebrates FMPs. The 2011 Caribbean ACL...

2011-11-07

439

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

...Coral and Reef Associated Plants and Invertebrates Fishery Management Plans of Puerto...Coral and Reef Associated Plants and Invertebrates Fishery Management Plans of Puerto...Corals and Reef Associated Plants and Invertebrates of Puerto Rico and the U.S....

2011-12-30

440

Short-term techniques for monitoring coral reefs: Review, results, and recommendations  

SciTech Connect

The health of coral reefs is in question on a global scale. The degradation of reefs has been attributed to both natural (e.g., el nino, crown-of-thorns, and hurricanes) and anthropogenic (e.g., sedimentation, nutrient overloading, oil spills, and thermal pollution) factors. Demonstrating the deleterious effects of lethal factors has not been difficult. However, it has been more difficult to quantitatively link those factors which do not cause rapid coral mortality to reef degradation. Classic techniques, such as cross-transplantation and x-ray analysis of growth bands, have proven to be successful bioassessments of chronic exposure to stressful conditions. The resolution of these techniques generally limits their usefulness as only long-term exposure (months to years) can provide quantitative differences between impacted and controlled conditions. Short-term monitoring techniques using corals have received relatively little attention from researchers. Two short-term methods have been successfully used to discriminated polluted from less-polluted sites in Barbados. The first is based on adult growth in several coral species. The second focuses on growth and survival of newly-settled juvenile corals. Both methods allowed discrimination in less than two weeks. These methods and others need to be evaluated and standardized in order to permit better, more efficient monitoring of the worlds reefs. Recommendations will be made on what life-history characteristics should be considered when choosing a coral species for use in bioassessment studies.

Mann, G.S. [EVS Consultants, Vancouver, British Columbia (Canada); Hunte, W.

1994-12-31

441

Kolmogorov-Smirnov like test for time-frequency Fourier spectrogram analysis in LISA Pathfinder  

NASA Astrophysics Data System (ADS)

A statistical procedure for the analysis of time-frequency noise maps is presented and applied to LISA Pathfinder mission synthetic data. The procedure is based on the Kolmogorov-Smirnov like test that is applied to the analysis of time-frequency noise maps produced with the spectrogram technique. The influence of the finite size windowing on the statistic of the test is calculated with a Monte Carlo simulation for 4 different windows type. Such calculation demonstrate that the test statistic is modified by the correlations introduced in the spectrum by the finite size of the window and by the correlations between different time bins originated by overlapping between windowed segments. The application of the test procedure to LISA Pathfinder data demonstrates the test capability of detecting non-stationary features in a noise time series that is simulating low frequency non-stationary noise in the system.

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

2014-12-01

442

Australian SKA Pathfinder: A High-Dynamic Range Wide-Field of View Survey Telescope  

NASA Astrophysics Data System (ADS)

The Australia SKA Pathfinder (ASKAP) is a new telescope under development as a world-class high-dynamic-range wide-field-of-view survey instrument. It will utilize focal plane phased array feeds on the 36 12-m antennas that will compose the array. The large amounts of data present a huge computing challenge, and ASKAP will store data products in an archive after near real-time pipeline processing. This powerful instrument will be deployed at a new radio-quiet observatory, the Murchison Radio-astronomy Observatory in the midwest region of Western Australia, to enable sensitive surveys of the entire sky to address some of the big questions in contemporary physics. As a pathfinder for the SKA, ASKAP will demonstrate field of view enhancement and computing/processing technology as well as the operation of a large-scale radio array in a remote and radio-quiet region of Australia.

DeBoer, D. R.; Gough, R. G.; Bunton, J. D.; Cornwell, T. J.; Beresford, R. J.; Johnston, S.; Feain, I. J.; Schinckel, A. E.; Jackson, C. A.; Kesteven, M. J.; Chippendale, A.; Hampson, G. A.; O'Sullivan, J. D.; Hay, S. G.; Jacka, C. E.; Sweetnam, T. W.; Storey, M. C.; Ball, L.; Boyle, B. J.

2009-08-01