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1

-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

2

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...

3

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

PubMed Central

Background The oral health education programs which have been organised and delivered in Tanzania were not based on a thorough understanding of behaviours which influence oral health. Therefore, evaluation of these programs became difficult. This study aimed at investigating the oral health related behaviours and their determinants among Tanzanian adults. Methods A national pathfinder cross sectional survey was conducted in 2006 involving 1759 respondents from the six geographic zones of mainland Tanzania. Frequency distributions, Chi square and multiple logistic regression analyses were performed using SPSS version 13.0. Results The rates of abstinence from alcohol for the past 30 days and life time smoking were 61.6% and 16.7% respectively, with males being more likely to smoke (OR 9.2, CI 6.3 -12.9, p < 0.001) and drink alcohol (OR 1.5, CI 1.2 -1.8, p < 0.001). Multiple regression analysis revealed that; having dental pain (OR 0.7, CI 0.5-0.8; p < 0.001) and being minimally educated (OR 0.48, CI 0.4-0.6; p < 0.001) reduced the likelihood of having a high sugar score. Whereas being male (OR 1.5, CI 1.2- 1.8; p < 0.001), urban (OR 1.9, CI 1.5 -2.3; p < 0.001), and young (OR 1.5, CI 1.2 -1.8; p < 0.001) increased the likelihood of having a high sugar score. Urban residents were less likely to take alcohol (OR 0.7, CI 0.6-0.9; p < 0.01), or smoke cigarette (OR = 0.7, CI = 0.6-0.9); less likely to be those who do not use fruits (OR 0.3, CI 0.2-0.4; p < 0.001); dental clinic (OR 0.5, CI 0.4-0.7; p < 0.001); factory made tooth brushes (OR 0.1, CI 0.08-0.17; p < 0.001) and toothpaste (OR 0.1, CI 0.1-0.2; p < 0.001) than their rural counterparts. More rural (13.2%) than urban (4.6%) residents used charcoal. Conclusion The findings of this study demonstrated social demographic disparities in relation to oral health related behaviors, while dental pain was associated with low consumption of sugar and high likelihood to take alcohol. PMID:19751519

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

2009-01-01

4

Spectrographic imaging: A bird's-eye view of the health of coral reefs  

NASA Astrophysics Data System (ADS)

Almost three-quarters of the world's coral reefs are thought to be deteriorating as a consequence of environmental stress. Until now, it has been possible to evaluate reef health only by field survey, which is labour-intensive and time-consuming. Here we map live coral cover from the air by remote imaging, a technique that will enable the state of shallow reefs to be monitored swiftly and over large areas.

Mumby, Peter J.; Chisholm, John R. M.; Clark, Chris D.; Hedley, John D.; Jaubert, Jean

2001-09-01

5

LISA Pathfinder  

NASA Technical Reports Server (NTRS)

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

Stebbins, Robin

2008-01-01

6

Reef Check  

NSDL National Science Digital Library

Reef Check, headquartered at the Institute of the Environment at the University of California Los Angeles, is a "volunteer, community-based monitoring protocol designed to measure the health of coral reefs on a global scale." With scientific reef surveys conducted in over 60 countries and territories, Reef Check has been able to track global trends in reef health to better inform possible conservation strategies. Visitors to the Reef Check Web site can read result summaries for the 1997-2001 monitoring period, and check out the organization's current and archived newsletters. Other resources include information on survey methods, Reef Check publications, a species identification guide, and other resources geared mainly toward Reef Check volunteers.

7

LISA Pathfinder  

NASA Astrophysics Data System (ADS)

LISA Pathfinder (formerly known as SMART-2) is an ESA mission designed to pave the way for the joint ESA/NASA Laser Interferometer Space Antenna (LISA) mission by testing in-flight the critical technologies required for space-borne gravitational wave detection; it will put two test masses in a near-perfect gravitational free fall, and control and measure their motion with an unprecedented accuracy. This is achieved through technology comprising inertial sensors, high-precision laser metrology, drag-free control and an ultra-precise micro-Newton propulsion system. The LISA Pathfinder mission is now in Phase C/Dthe Implementation Phase, and is due to be launched in 2010, with results on the performance of the system being available within 6 months thereafter.

McNamara, P.; Vitale, S.; Danzmann, K.; LISA Pathfinder Science Working Team

2008-06-01

8

LISA Pathfinder  

NASA Astrophysics Data System (ADS)

LISA Pathfinder (formerly known as SMART-2) is an ESA mission designed to pave the way for the joint ESA/NASA Laser Interferometer Space Antenna (LISA) mission by testing in flight the critical technologies required for space-borne gravitational wave detection; it will put two test masses in a near-perfect gravitational free-fall and control and measure their motion with 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. The LISA Pathfinder mission is now in Phase C/D (detailed design phase), and is due to be launched in late 2009, with results on the performance of the system being available approximately 6 months later.

McNamara, P. W.

2006-11-01

9

The health and future of coral reef systems  

Microsoft Academic Search

Coral reefs are among the most productive and diverse ecosystems on earth and provide a multitude of valuable ecosystem services. Moreover, the resources derived from coral reefs are essential to the food security of millions of people living within tropical coastal communities. Unfortunately, burgeoning human populations in coastal regions are placing an unsustainable burden on these resources such that degradation

David W Souter; Olof Lindn

2000-01-01

10

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

NASA Astrophysics Data System (ADS)

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

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

2003-12-01

11

Assessing coral reef health across onshore to offshore stress gradients in the US Virgin Islands.  

PubMed

Managing the effects of anthropogenic disturbance on coral reefs is highly dependant on effective strategies to assess degradation and recovery. We used five years of field data in the US Virgin Islands to investigate coral reef response to a potential gradient of stress. We found that the prevalence of old partial mortality, bleaching, and all forms of coral health impairment (a novel category) increased with nearshore anthropogenic processes, such as a five-fold higher rate of clay and silt sedimentation. Other patterns of coral health, such as recent partial mortality, other diseases, and benthic cover, did not respond to this potential gradient of stress or their response could not be resolved at the frequency or scale of monitoring. We suggest that persistent signs of disturbance are more useful to short-term, non-intensive (annual) coral reef assessments, but more intensive (semi-annual) assessments are necessary to resolve patterns of transient signs of coral health impairment. PMID:18834601

Smith, T B; Nemeth, R S; Blondeau, J; Calnan, J M; Kadison, E; Herzlieb, S

2008-12-01

12

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

13

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

14

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

15

Use of Integrated Landscape Indicators to Evaluate the Health of Linked Watersheds and Coral Reef Environments in the Hawaiian Islands  

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

16

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

NASA Astrophysics Data System (ADS)

Human-induced climate change has already led to substantial changes in a variety of ecosystems. Coral reefs are particularly vulnerable to rises in ocean temperature as a result of climate change because they already live near their thermal limits. However, we know little about the spatial patterns of temperature anomalies, areas of greater than usual temperature, which cause coral mortality and increased rates of coral disease. These gaps in knowledge make it difficult to design effective management strategies for mitigating the effects of ocean warming. My dissertation research uses a combination of a new satellite ocean temperature dataset, field surveys on coral health, and data on marine protected area (MPA) boundaries to analyze how ocean temperatures are affecting coral reef health at regional and global scales. I discovered that temperature anomalies are spatially and temporally variable from 1985-2005 even during El Nino events. They are also typically less than 50 km2, smaller than the resolution of many climate models. In addition, I found a strong relationship on the Great Barrier Reef between the number of temperature anomalies and the number of cases of white syndrome, a prevalent coral disease. Results from this study suggest that temperature anomalies are playing a major role in the observed decline of coral reefs over the last 30-40 years. This decline highlights the importance of determining whether MPAs, one of the most common management tools are effective in restoring coral cover. My analyses demonstrated that MPAs can confer some ecosystem resilience through fisheries management and land management practices at regional scales. Coral cover on reefs inside of MPAs did not change over time, while unprotected reefs experienced declines in coral cover. However, MPAs do not moderate the effect of thermal stress on corals or reduce coral decline at rates that can offset losses from thermal stress and other major natural and human-caused disturbances. MPAs are clearly a key tool in the management of fisheries and coral reef health. My dissertation research underscores the need for both MPAs and additional measures aimed at reducing the anthropogenic activities driving climate change.

Selig, Elizabeth Rose

17

Pathfinder aircraft in flight  

NASA Technical Reports Server (NTRS)

The unique Pathfinder solar-powered flying wing, is shown during a checkout flight from the Dryden Flight Research Center, Edwards, California. This two-hour low-altitude flight over Rogers Dry Lake, Nov. 19, 1996, served to test aircraft systems and functional procedures, according to officials of AeroVironment, Inc., Pathfinder's developer and operator. 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

18

Pathfinder aircraft in flight  

NASA Technical Reports Server (NTRS)

The Pathfinder research aircraft's solar cell arrays are prominently displayed as it touches down on the bed of Rogers Dry Lake at the Dryden Flight Research Center, Edwards, California, following a test flight. The solar arrays covered more than 75 percent of Pathfinder's upper wing surface, and provided electricity to power its six electric motors, flight controls, communications links and a host of scientific sensors. 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

19

Pathfinder aircraft flight  

NASA Technical Reports Server (NTRS)

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

1996-01-01

20

Pathfinder aircraft checkout flight  

NASA Technical Reports Server (NTRS)

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

1996-01-01

21

Pathfinder aircraft in flight  

NASA Technical Reports Server (NTRS)

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

1996-01-01

22

Pathfinder aircraft in flight  

NASA Technical Reports Server (NTRS)

The Pathfinder solar-powered research aircraft heads for landing on the bed of Rogers Dry Lake at the Dryden Flight Research Center, Edwards, California, after a successful test flight Nov. 19, 1996. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

1996-01-01

23

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.

Leinfelder, Reinhold

24

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

25

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. (See the Pathfinder Plus photos and project description.)

1995-01-01

26

NOAA's Coral Reef  

NSDL National Science Digital Library

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

27

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

28

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 verification mission for future space-borne gravitational wave detectors. LISA Pathfinder essentially mimics one arm of a gravitational wave detector by shrinking the million kilometre-scale armlength down to a few tens of centimetres, giving up the sensitivity to gravitational waves, but keeping the measurement technology. The experimental concept is to measure the relative separation between two test masses nominally following their own geodesics, and thereby determine the relative residual acceleration between them over timescales of ~1000seconds. In this paper I will present the LPF mission concept, the status of the mission, and the route from LISA Pathfinder to future gravitational wave missions.

McNamara, Paul

29

Pathfinder: A Retrospective  

NASA Technical Reports Server (NTRS)

Mars is one of the most interesting planets in the solar system, featuring enormous canyons, giant volcanoes, and indications that, early in its history, it might have had rivers and perhaps even oceans. Five years ago, in July of 1997, the Pathfinder mission landed on Mars, bringing with it the microwave-oven sized Sojourner rover to wander around on the surface and analyse rocks. Among the experiments on the mission was one designed to analyse dust deposition. Pathfinder is only the first of an armada of spacecraft which will examine Mars from the pole to the equator in the next decade, culminating with a mission to bring humans to Mars.

Landis, Geoffrey A.; Lyons, Valerie (Technical Monitor)

2002-01-01

30

Health of the coral reefs at the US Navy Base, Guantnamo 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 Guantnamo 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 Guantnamo 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

31

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 validation mission for future interferometric spaceborne gravitational wave observatories, for example the proposed eLISA mission. The technologies required for eLISA 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 eLISA technologies in a flight environment. LISA Pathfinder essentially mimics one arm of the eLISA 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 eLISA 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

2013-04-01

32

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

33

Martian terrain near Pathfinder  

NASA Technical Reports Server (NTRS)

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

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

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

1997-01-01

34

The LISA Pathfinder mission  

NASA Astrophysics Data System (ADS)

LISA Pathfinder (formerly known as SMART-2) is an ESA mission designed to pave the way for the joint ESA/NASA Laser Interferometer Space Antenna (LISA) mission by testing in flight the critical technologies required for space-borne gravitational wave detection: it will put two test masses in a near-perfect gravitational free-fall and control and measure their motion with unprecedented accuracy. This is achieved through technology comprising inertial sensors, high precision laser metrology, drag-free control and an ultra-precise micro-Newton propulsion system LISA Pathfinder is scheduled to be launched in the first half of 2010 to a Lissajous orbit around the first Sun-Earth Lagrange point, L1. In addition to a complete European technology package (the LISA Technology Package, or LTP), LISA Pathfinder will also carry thrusters and software, known as ST-7, a part of NASA's New Millennium Program. Here I will give an introduction to, and status of, the mission, followed by a discussion on the technologies to be tested. Finally I will discuss the ways in which the LISA Pathfinder mission will be used for preparation of LISA (e.g. ground segment development as well as technology development) and for other future missions (formation flying, Fundamental Physics Explorer, etc.).

McNamara, Paul

35

The LISA Pathfinder Mission  

NASA Astrophysics Data System (ADS)

LISA Pathfinder is a dedicated technology demonstration space mission for the Laser Interferometer Space Antenna (LISA), a NASA/ESA collaboration to operate a space-based observatory for gravitational waves in the milliHertz band. Although the formal partnership between the agencies was dissolved in the Spring of 2011, both agencies are actively pursuing concepts for LISA-like gravitational wave observatories. These concepts take advantage of the significant technology development efforts that have already been made, especially those of the LISA Pathfinder mission. LISA Pathfinder, which is in the late stages of implementation, will place two test masses in drag-free flight and measure the relative acceleration between them. This measurement will validate a number of technologies that are critical to LISA-like gravitational wave instruments including sensing and control of the test masses, drag-free control laws, micro-Newton thrusters, and picometer-level laser metrology. We will present the current status of the LISA Pathfinder mission and associated activities.

Thorpe, James; Namara, P. W. Mc.; LISA Pathfinder Team

2012-01-01

36

The LISA Pathfinder Mission  

NASA Astrophysics Data System (ADS)

LISA Pathfinder (formerly known as SMART-2) is an ESA mission designed to pave the way for the joint ESA/NASA Laser Interferometer Space Antenna (LISA) mission by testing in flight the critical technologies required for space-borne gravitational wave detection: it will put two test masses in a near-perfect gravitational free-fall and control and measure their motion with unprecedented accuracy. LISA Pathfinder will carry two technology payloads, the European provided LISA Technology Package (LTP), and the NASA provided Disturbance Reduction System (DRS). The LTP comprises two inertial sensors, high precision laser metrology, drag-free control and an ultra-precise micro-Newton propulsion system. The DRS consists of a drag-free control system and a micro-Newton propulsion system. The DRS will use the LTP inertial sensors. LISA Pathfinder is due to be launched in late 2009, with first results on the performance of the system being available approx 6 months later. This poster gives an introduction to, and status of, the mission, followed by more details on the technologies to be tested in a space environment. It will also highlight the ways in which the LISA Pathfinder mission will be used for the preparation of LISA, e.g. ground segment development, on-orbit commissioning of the hardware, etc. as well as technology development.

Stebbins, Robin T.; LISA Pathfinder Science Team

2006-12-01

37

Coral Reefs Under Stress  

NSDL National Science Digital Library

Coral reefs are more critical to an oceanâs 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

38

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

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

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

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.; Garca Marirrodriga, C.; Gerndt, R.; Gesa, L.; Gibert, F.; Giardini, D.; Grimani, C.; Grynagier, A.; Guzmn, 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

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

43

The Mars Pathfinder Mission  

NASA Technical Reports Server (NTRS)

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 surface 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 of square meters on Mars, which will provide a calibration point or "ground truth" for orbital remote sensing observations. In addition to the rover, which also performs a number of technology experiments, Pathfinder carries three science instruments: a stereoscopic imager with spectral filters on an extendable mast, an alpha proton X ray spectrometer, and an atmospheric structure instrument/meteorology package. The instruments, the rover technology experiments, and the telemetry system will allow investigations of the surface morphology and geology at submeter to a hundred meters scale, the petrology and geochemistry of rocks and soils, the magnetic properties of dust, soil mechanics and properties, a variety of atmospheric investigations, and the rotational and orbital dynamics of Mars. Landing downstream from the mouth of a giant catastrophic outflow channel, Ares Vallis at 19.5 deg N, 32.8 deg W, offers the potential of identifying and analyzing a wide variety of crustal materials, from the ancient heavily cratered terrain, intermediate-aged ridged plains, and reworked channel deposits, thus allowing first-order scientific investigations of the early differentiation and evolution of the crust, the development of weathering products, and tile early environments and conditions on Mars.

Golombek, Matthew P.

1997-01-01

44

The Mars Pathfinder Mission  

NASA Astrophysics Data System (ADS)

The Mars Pathfinder mission is a Discovery class mission that will place a small lander and rover on the surface of Mars on July 4, 1997. The Pathfinder flight system is a single small lander, packaged within an aeroshell and back cover with a back-pack-style cruise stage. The vehicle will be launched, fly independently to Mars, and enter the atmosphere directly on approach behind the aeroshell. The vehicle is slowed by a parachute and 3 small solid rockets before landing on inflated airbags. Petals of a small tetrahedron shaped lander open up, to right the vehicle. The lander is solar powered with batteries and will operate on the surface for up to a year, downlinking data on a high-gain antenna. Pathfinder will be the first mission to use a rover, with 3 imagers and an alpha proton X-ray spectrometer, to characterize the rocks and soils in a landing area over hundreds of square meters on Mars, which will provide a calibration point or "ground truth" for orbital remote sensing observations. The rover (includes a series of technology experiments), the instruments (including a stereo multispectral surface imager on a pop up mast and an atmospheric structure instrument-surface meteorology package) and the telemetry system will allow investigations of: the surface morphology and geology at meter scale, the petrology and geochemistry of rocks and soils, the magnetic properties of dust, soil mechanics and properties, a variety of atmospheric investigations and the rotational and orbital dynamics of Mars. Landing downstream from the mouth of a giant catastrophic outflow channel, Ares Vallis, offers the potential of identifying and analyzing a wide variety of crustal materials, from the ancient heavily cratered terrain, intermediate-aged ridged plains and reworked channel deposits, thus allowing first-order scientific investigations of the early differentiation and evolution of the crust, the development of weathering products and early environments and conditions on Mars.

Golombek, M. P.

1996-09-01

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

Coral Reefs  

NSDL National Science Digital Library

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

Amsden

2009-11-19

47

Reef ED  

NSDL National Science Digital Library

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

48

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

49

LISA Pathfinder ground testing  

NASA Astrophysics Data System (ADS)

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

Guzman, Felipe; LISA Pathfinder Team

2010-01-01

50

Launch Abort System Pathfinder Arrival  

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...

51

Spacetime Metrology with LISA Pathfinder  

Microsoft Academic Search

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

Giuseppe Congedo

2012-01-01

52

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.; Garca Marin, A.; Garca Marirrodriga, C.; Gerndt, R.; Gesa, L.; Gilbert, F.; Giardini, D.; Grimani, C.; Grynagier, A.; Guillaume, B.; Guzmn, 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

53

Mars Pathfinder Preliminary Results  

NASA Astrophysics Data System (ADS)

Pathfinder plays a key role as the first of the Surveyor series and as the first Discovery project to complete its mission. On July 4 the Pathfinder lands at Ares Vallis chosen as a grab-bag sample of small rocks washed down from the highland regions by the ancient catastrophic floods that once inundated the region. A multi-spectral, stereoscopic camera (IMP) was selected with the capability to discriminate rock types according to their spectral signatures between 0.4 and 1.1 microns. This range gives information on the iron mineralogies (the weathering of ferrous to ferric minerals) and some compositional information with the 0.9 micron pyroxene band. Stereo rangefinding allows contour-mapping of the surface, calculation of rock sizes, and helps with rover guidance. Operationally the camera data determines which rocks seem spectrally interesting and the stereo images allow the rover team to station the APXS against the rock for a night-long integration. The resulting data constrains the elemental composition which is then combined with the spectral data to determine the mineralogy of the rock. The study of the atmosphere is also a prime scientific goal. The ASI/MET team has instruments for measuring diurnal temperature and pressure variations as well as wind velocity. During the descent they also derive the vertical profiles of the atmosphere. IMP has three windsocks that are monitored hourly for wind signatures; looking at all three simultaneously gives the vertical wind gradient. IMP also has 8 atmospheric filters that allow the camera to image the sun directly and measure the opacity variations hourly throughout the day. At night, bright star and Phobos observations with the geology filters continue the characterization. Besides the dust opacity, three filters in the 0.94 micron water band are able to measure water vapor at large airmass factors. Finally, a series of magnets at various positions on the lander will show indications of the magnetic properties of windblown dust. This scientific station could last as long as an earth year on Mars; therefore, seasonal changes in the weather and surface can be tracked.

Smith, P. H.

1997-07-01

54

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

Microsoft Academic Search

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

Elizabeth Rose Selig

2008-01-01

55

Pathfinder being prepared for flight  

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 propeller-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.

1997-01-01

56

Mars Pathfinder Landing Site Workshop  

NASA Technical Reports Server (NTRS)

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

Golombek, Matthew (editor)

1994-01-01

57

Status of coral reef and reef fish resources of Vanuatu  

Microsoft Academic Search

The coral reefs of Vanuatu contribute to rural incomes, nutrition, shoreline protection and, more importantly, self reliance for the people of Vanuatu. The total area of shallow water benthic coral communities is relatively small, approximately 408 square kilometres out of a combined land area of 12, 190 square kilometres. Although there are many reefs of exceptional beauty in good health,

William Naviti; James Aston

58

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

Microsoft Academic Search

Run-off containing increased concentrations of sediment, nutrients, and pesticides from land-based anthropogenic activities\\u000a is a significant influence on water quality and the ecologic conditions of nearshore areas of the Great Barrier Reef World\\u000a Heritage Area, Australia. The potential and actual impacts of increased pollutant concentrations range from bioaccumulation\\u000a of contaminants and decreased photosynthetic capacity to major shifts in community structure

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

2007-01-01

59

Reef Relief  

NSDL National Science Digital Library

This website includes a thorough overview of coral reefs around the globe, including the threats facing them, current protection projects, and action you can take to help save reefs. The "International Projects" and "The Coral Reef Ecosystem" sections are full of fantastic photographs and other information. Educational materials may be purchased and include DVDs and teacher's guides. Many volunteer and donation opportunities are available. A children's section includes information-filled printable coloring pages. Several different publications are available at no cost.

2011-10-05

60

Reef Relief  

NSDL National Science Digital Library

A thorough overview of coral reefs around the globe, including the threats facing them, current protection projects, and action you can take to help save reefs. "International Projects" and "The Coral Reef Ecosystem" sections are chock-full of fantastic photographs and information. Education materials may be purchased and include DVDs and teacher's guides. Many volunteer and donation opportunities. Children section includes information-filled printable coloring pages. Several different publications are available at no cost.

61

Mars Pathfinder project progress report  

Microsoft Academic Search

Mars Pathfinder, designed and built at the Jet Propulsion Laboratory\\/California Institute of Technology under contract to NASA's Office of Space Science, is the second of NASA's cheaper, better, faster Discovery missions; the first, the Near Earth Asteroid Rendezvous mission, was launched February 17, 1996 to tag up with Eros in February 1999. Launching on December 2, 1996 and landing on

Anthony J. Spear; Matthew P. Golombek

1996-01-01

62

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

63

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

64

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

65

Coral Reefs  

NSDL National Science Digital Library

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

66

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

67

A Pathfinder for Juvenile Diabetes  

Microsoft Academic Search

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

Maxine Streeter

2000-01-01

68

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

69

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

70

Electrostatic disturbances aboard LISA Pathfinder  

NASA Astrophysics Data System (ADS)

Test mass charging and stray electrostatic fields are a potentially important source of force noise for the LISA Pathfinder mission. During the flight we plan to measure the relevant stray electrostatic fields on the surfaces of both the test mass and the electrode housing and compensate them with DC electrode bias voltages. In addition we monitor the charge and reduce it to near zero by UV illumination. We describe the analysis techniques used during the mission and explain the importance of periodic charging/discharging and of long-term charge measurements to limit the force noise at low frequency, which is particularly relevant for the eLISA mission.

Ferroni, Valerio

71

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 Nia 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 2628C when autotrophic indices (chl a and zooxanthellae density) were lowest. The extreme temperature during the La Nia 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 Nia 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

72

Pathfinder aircraft being assembled - wing assembly  

NASA Technical Reports Server (NTRS)

Technicians easily lift a 20-foot-long wing section during assembly of the Pathfinder solar-powered research aircraft at NASA's Dryden Flight Research Center, Edwards, California. A number of upgrades were made to the unique aircraft prior to its successful checkout flight Nov. 19, 1996, among them the installation of stronger ultra-light wing ribs made of composite materials on two of the five wing panels. 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

73

Pathfinder - flight preparation on lakebed at sunrise  

NASA Technical Reports Server (NTRS)

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

1994-01-01

74

Pathfinder - flight preparation on lakebed at sunrise  

NASA Technical Reports Server (NTRS)

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

1995-01-01

75

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

76

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. Thi...

Congedo, Giuseppe

2012-01-01

77

Northeast View From Pathfinder Lander  

NASA Technical Reports Server (NTRS)

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

This view was produced by combining 8 individual 'Superpan' scenes from the left and right eyes of the IMP camera. Each frame consists of 8 individual frames (left eye) and 7 frames (right eye) taken with different color filters that were enlarged by 500% and then co-added using Adobe Photoshop to produce, in effect, a super-resolution panchromatic frame that is sharper than an individual frame would be.

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

1997-01-01

78

Coral Reefs  

NSDL National Science Digital Library

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

79

Pathfinder aircraft returning from a flight  

NASA Technical Reports Server (NTRS)

The Pathfinder solar-powered research aircraft settles in for landing on the bed of Rogers Dry Lake at the Dryden Flight Research Center, Edwards, California, after a successful test flight Nov. 19, 1996. The ultra-light craft flew a racetrack pattern at low altitudes over the flight test area for two hours while project engineers checked out various systems and sensors on the uninhabited aircraft. The Pathfinder was controlled by two pilots, one in a mobile control unit which followed the craft, the other in a stationary control station. Pathfinder, developed by AeroVironment, Inc., is one of several designs 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. (See the Pathfinder Plus photos and project description.)

1996-01-01

80

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

81

Coral Reef Conservation through Outreach Education Judith C. LANG  

E-print Network

Coral Reef Conservation through Outreach Education Judith C. LANG , Janie L. WULFF , Carol R, USA * National Coral Reef Institute, Dania Beach, Florida, USA; fretwelc@nsu.nova.edu; fax, +1 threaten coral reefs and undermine the capability of tropical coastal populations to meet basic health

Ronquist, Fredrik

82

The Global Coral Reef Crisis: Trends and Solutions (Coral Reefs: Values, Threats, and the Marine Aquarium Trade)  

SciTech Connect

Second only to tropical rainforests, coral reefs support one of the world's most diverse natural habitats. Over 350 million individuals depend on coral reef resources for food and income. Unfortunately, the Earth is in the midst of a coral reef crisis. Anthropogenic impacts including overfishing, destructive fishing practices, sedimentation and pollution, as well as global climate change, have served to disrupt the natural processes that maintain the health of these ecosystems. Until recently, however, the global extent of the coral reef crisis was unknown. Reef Check was developed in 1996 as a volunteer, community-based monitoring protocol designed to measure the health of coral reefs on a global scale. With goals of education, monitoring, and management, Reef Check has activities in over 60 countries and territories. They have not only provided scientific evidence of the global extent of the coral reef crisis, but have provided the first community based steps to alleviate this urgent situation.

Shuman, Craig S. (Reef Check, UCLA) [Reef Check, UCLA

2003-02-05

83

Model Checking JAVA Programs Using Java Pathfinder.  

National Technical Information Service (NTIS)

This paper describes a translator called JAVA PATHFINDER from JAVA to PROMELA, the 'programming language' of the SPIN model checker. The purpose is to establish a framework for verification and debugging of JAVA programs based on model checking. This work...

K. Havelund, T. Pressburger

2000-01-01

84

Jurassic Reef Park  

NSDL National Science Digital Library

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

85

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

86

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

87

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

88

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

89

LISA Pathfinder instrument data analysis  

NASA Astrophysics Data System (ADS)

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

Guzman, Felipe

90

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

91

Reef Education Network  

NSDL National Science Digital Library

The University of Queensland's Reef Education Network (REN) is a wonderful introduction to the amazing world of coral reefs. REN has some cool images as well as information about reef research, current problems threatening coral reefs, and the many fascinating organisms that reside within a coral reef. The Life And Times section provides a nice overview of what a reef is, while the Ask A Brain Coral section gives some introduction to biotic and abiotic relationships that occur within reefs. A unique feature is the notebook, where students can record and organize information as they navigate throughout the site.

2001-01-01

92

Dust on Mars: Materials Adherence Experiment results from Mars Pathfinder  

Microsoft Academic Search

Mars Pathfinder is the first solar-powered probe to operate on the surface of Mars. Pathfinder consists of a lander and a small, autonomous, six-wheel solar-powered rover, Sojourner. The Pathfinder spacecraft reflects NASA's new philosophy of exploiting new technologies to reduce mission cost. The Materials Adherence Experiment on Pathfinder was designed to measure the degradation of solar arrays due to dust

Geoffrey A. Landis; Phillip P. Jenkins

1997-01-01

93

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

94

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

95

Pathfinders on Black Dance in America.  

ERIC Educational Resources Information Center

This is a compilation of 18 pathfinders (i.e., a bibliographic instruction aid) on black dance in America, prepared by graduate students in the "Information Resources in the Humanities" and the "Information Resources in the Social Sciences" classes in the Graduate School of Library and Information Science at the University of Texas at Austin. The

Roy, Loriene, Ed.

96

Mars Pathfinder, Science Results, Geology and Geomorphology  

NSDL National Science Digital Library

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

97

The role of SCUBA diver user fees as a source of sustainable funding for coral reef marine Protected areas  

Microsoft Academic Search

Coral reefs are both highly diverse and economically important. Human activities, however, threaten the world's coral reefs, endangering their biological and economic value. No take Marine Protected Areas (MPA), which ban fishing within MPA boundaries, help conserve and restore reef health and provide ecological resilience to reefs in the face of global warming and ocean acidification. In many cases, cost-benefit

Elizabeth Terk; Nancy Knowlton

2010-01-01

98

Coral Reef Ecosystems: The Living Reef  

NSDL National Science Digital Library

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

National Science Teachers Association (NSTA)

2006-11-01

99

Coral Reef Connections  

NSDL National Science Digital Library

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

100

Great Barrier Reef  

NSDL National Science Digital Library

This Landsat-7 color composite image shows a section of the famous Great Barrier Reef, the world's largest living organism. This view displays the southern end of the reef where it is composed of smaller, individual reef structures as opposed to a continuous bank as in the north.

Nasa; Day, Earth S.

101

Planetary Coral Reef Foundation  

NSDL National Science Digital Library

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

102

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.

103

Coral Reef Adventure  

NSDL National Science Digital Library

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

Freeman, Macgillivray

104

NOAA Coral Reef Watch Calcification Index of Coral Reef Ecosystems  

E-print Network

NOAA 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, Maryland #12;Presentation Outline · NOAA Coral Reef Watch ­ Mission and Challenges · Research Impetus

Kuligowski, Bob

105

Dioramas: Andros Coral Reef  

NSDL National Science Digital Library

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

106

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

107

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

108

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-Franois; Davis, Greg; Deng, Meiling; Denman, Nolan; Dobbs, Matt; Fandino, Mateus; Gibbs, Kenneth; Gilbert, Adam; Halpern, Mark; Hanna, David; Hincks, Adam D.; Hinshaw, Gary; Hfer, 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

109

Web based education and the Pathfinder project  

E-print Network

FIGURE Page I Pathfinder Splash Page 2 Technology Transfer Documents Page 3 Document Containing the Software Implementation Plan Under Technology Transfer Documents, Sub-category Job Cost Estimation: Models and Tools . 4 SmartCost? Archilecturc. 13..., it is a priceless tool used in determining the "how-to" systems engineering procedure for constructing activity and process models to capture, access and use costing in I ormation. CHAPTER HI INTERNET SITE DESIGN Corporations, organizations...

Crino, Scott Thomas

2012-06-07

110

Author's personal copy Coral Reefs  

E-print Network

in the Ecology of Reefs Landscape Ecology of Coral Reefs: Connections of Coral Reefs to Mangrove and Seagrass worldwide (Figure 1). Coral reefs also support human societies by providing critical sources of protein ecosystems such as seagrass beds and mangrove forests. Finally, we review the current dangers to coral reefs

Burkepile, Deron

111

Coral Reef Ecosystems  

NSDL National Science Digital Library

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

National Science Teachers Association (NSTA)

2007-03-28

112

PATHFINDER ATOMIC POWER PLANT. BORON STAINLESS STEEL CONTROL RODS FOR PATHFINDER REACTOR. Final Summary Report  

Microsoft Academic Search

An extensive development, fabrication, and design analysis program was ; completed on 2 wt% boron stainiess steel for Pathfinder boiler and superheater ; control rods. Results indicated that the control rods will operate ; satisfactorily in the reactor under all foreseeable conditions. It was concluded ; that the maximum local burnup on the boiler rods is limited to 1.0 core

D. A. Patterson; D. A. Nehrig; R. H. Klumb; T. E. Peterson

1963-01-01

113

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

114

New directions in coral reef microbial ecology.  

PubMed

Microbial processes largely control the health and resilience of coral reef ecosystems, and new technologies have led to an exciting wave of discovery regarding the mechanisms by which microbial communities support the functioning of these incredibly diverse and valuable systems. There are three questions at the forefront of discovery: What mechanisms underlie coral reef health and resilience? How do environmental and anthropogenic pressures affect ecosystem function? What is the ecology of microbial diseases of corals? The goal is to understand the functioning of coral reefs as integrated systems from microbes and molecules to regional and ocean-basin scale ecosystems to enable accurate predictions of resilience and responses to perturbations such as climate change and eutrophication. This review outlines recent discoveries regarding the microbial ecology of different microenvironments within coral ecosystems, and highlights research directions that take advantage of new technologies to build a quantitative and mechanistic understanding of how coral health is connected through microbial processes to its surrounding environment. The time is ripe for natural resource managers and microbial ecologists to work together to create an integrated understanding of coral reef functioning. In the context of long-term survival and conservation of reefs, the need for this work is immediate. PMID:21955796

Garren, Melissa; Azam, Farooq

2012-04-01

115

Immersive Environments for Mission Operations: Beyond Mars Pathfinder  

Microsoft Academic Search

Immersive environments are just beginning to be used to support mission operations at the Jet Propulsion Laboratory. This technology contributed to the Mars Pathfinder Mission in planning sorties for the Sojourner rover. Utilizing stereo imagery from the Imager for Mars Pathfinder (IMP) camera enabled the operator to visualize the terrain from the lander's point of view in 3D to assist

John Wright; Frank Hartman; Brian Cooper

116

Pathfinders for Finding Information on Native Americans with Disabilities.  

ERIC Educational Resources Information Center

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

Roy, Loriene, Comp.

117

Pathfinder Instruments for Cloud and Aerosol Spaceborne Observations (PICASSO)  

NASA Technical Reports Server (NTRS)

This paper will describe the planned 3-year Pathfinder Instruments for Cloud and Aerosol Spaceborne Observations (PICASSO) mission, its instrumentation and implementation. It will use LITE and other data, plus analyses, to show the feasibility of such a mission. PICASSO is being proposed for NASA's Earth System Science Pathfinder (ESSP) program with launch predicted in 2003.

McCormick, M. Patrick; Winker, David M.

1998-01-01

118

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

E-print Network

Entertainment Research School of Computer Science, University of Windsor Windsor, Ontario, Canada sgoodwin. Introduction Pathfinding is a fundamental problem that typical commercial games must deal with in one form) to the deepest, darkest dungeons as well. 2. Pathfinding in practice A* search is among the most popular

Pratt, Vaughan

119

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

120

Pathfinder aircraft prepared for flight at dawn on lakebed  

NASA Technical Reports Server (NTRS)

The Pathfinder solar-powered research aircraft is silhouetted by the morning sun on the bed of Rogers Dry Lake as technicians prepare it for flight. The unique remotely piloted flying wing flew for two hours under control of a ground-based pilot on Nov. 19, 1996, at NASA's Dryden Flight Research Center, Edwards, California, while engineers checked out various aircraft systems. 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

121

Pathfinder aircraft taking off - setting new solar powered altitude record  

NASA Technical Reports Server (NTRS)

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

1995-01-01

122

Pathfinder - closeup of flight preparation on lakebed at sunrise  

NASA Technical Reports Server (NTRS)

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

1995-01-01

123

Pathfinder - closeup of flight preparation on lakebed at sunrise  

NASA Technical Reports Server (NTRS)

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

1995-01-01

124

Reef Education Evaluation: Environmental Knowledge and Reef Experience  

ERIC Educational Resources Information Center

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

Stepath, Carl M.

2005-01-01

125

U.S. Coral Reef Taskforce  

NSDL National Science Digital Library

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

126

Overhead View of Pathfinder Landing Site  

NASA Technical Reports Server (NTRS)

Planimetric (overhead view) map of the landing site, to a distance of 20 meters from the spacecraft. North is at the top in this and Plates 3-5. To produce this map, images were geometrically projected onto an assumed mean surface representing the ground. Features above the ground plane (primarily rocks) therefore appear displaced radially outward; the amount of distortion increases systematically with distance. The upper surfaces of the lander and rover also appear enlarged and displaced because of their height. Primary grid (white) is based on the Landing Site Cartographic (LSC) coordinate system, defined with X eastward, Y north, and Z up, and origin located at the mean ground surface immediately beneath the deployed position of the IMP camera gimbal center. Secondary ticks (cyan) are based on the Mars local level (LL) frame, which has X north, Y east, Z down, with origin in the center of the lander baseplate. Rover positions (including APXS measurements) are commonly reported in the LL frame. Yellow grid shows polar coordinates based on the LSC system. Cartographic image processing by U.S. Geological Survey.

NOTE: original caption as published in Science Magazine

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

1997-01-01

127

Imager for Mars Pathfinder Windsock Experiment  

NASA Astrophysics Data System (ADS)

The Imager for Mars Pathfinder (IMP) camera[1] will be launched aboard the Pathfinder spacecraft toward Mars in December, 1996 for a July, 1997 arrival on the surface. Three windsocks were developed for attachment to the one-meter mast of the Atmosphere Structure Instrument/Meteorology (ASI/Met) package. The windsocks will be imaged repeatedly (with sub-framing and compression) over short intervals to allow measurement of the wind speed boundary-layer profile, including determination of aerodynamic roughness, wind friction speed, and shear stress on the surface due to wind. The ability to determine these parameters allows evaluation of the potential of wind to move fine particles across the landing site. Changes in the surface distribution of mobile materials during the mission can be related to aerodynamic roughness and friction speed determined from IMP windsock images. Surface changes and winds at the landing site might also be related to wind streaks and other albedo features within the landing ellipse seen in Viking Orbiter images.

Sullivan, R.; Greeley, R.; Wilson, G.; Smith, P.; Cooper, C.

1996-03-01

128

Mars Pathfinder flight system integration and test.  

NASA Astrophysics Data System (ADS)

This paper describes the system integration and test experiences, problems and lessons learned during the assembly, test and launch operations (ATLO) phase of the Mars Pathfinder flight system scheduled to land on the surface of Mars on July 4, 1997. The Mars Pathfinder spacecraft consists of three spacecraft systems: cruise stage, entry vehicle and lander. The cruise stage carries the entry and lander vehicles to Mars and is jettisoned prior to entry. The entry vehicle, including aeroshell, parachute and deceleration rockets, protects the lander during the direct entry and reduces its velocity from 7.6 to 0 km/s in stages during the 5 min entry sequence. The lander's touchdown is softened by airbags which are retracted once stopped on the surface. The lander then uprights itself, opens up fully and begins surface operations including deploying its camera and rover. This paper overviews the system design and the results of the system integration and test activities, including the entry, descent and landing subsystem elements. System test experiences including science instruments, the microrover, Sojourner, and software are discussed. The final qualification of the entry, descent and landing subsystems during this period is also discussed.

Muirhead, B. K.

129

Canadian Hydrogen Intensity Mapping Experiment (CHIME) Pathfinder  

E-print Network

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 beamforming that characterized previous designs. The Pathfinder consists of two cylinders 37\\,m long by 20\\,m 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 ...

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

2014-01-01

130

Create a Coral Reef  

NSDL National Science Digital Library

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

131

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

132

Exploring the reefs Introduction  

E-print Network

chain. Many people depend on the reefs for food and economy (fish, shellfish, etc.). Coral reefs thrive in clear, unpolluted water; however, they currently face a number of threats from pollution, sedimentation in the atmosphere, as well as pollution and waves in the water can affect the depth of detection by the satellite

Wright, Dawn Jeannine

133

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.

134

Assessing the deep reef refugia hypothesis: focus on Caribbean reefs  

Microsoft Academic Search

Coral reefs in shallow-water environments (<30m) 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

135

Human impacts on Caribbean coral reef ecosystems  

E-print Network

2006) Conservation, precaution, and Caribbean reefs. Coral2006) Conservation, precaution, and Caribbean reefs. CoralConservation. Hardt, MJ, Contextualizing the historical collapse of Jamaican coral reefs.

Hardt, Marah Justine

2007-01-01

136

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

137

Big Crater as Viewed by Pathfinder Lander  

NASA Technical Reports Server (NTRS)

The 'Big Crater' is actually a relatively small Martian crater to the southeast of the Mars Pathfinder landing site. It is 1500 meters (4900 feet) in diameter, or about the same size as Meteor Crater in Arizona. Superimposed on the rim of Big Crater (the central part of the rim as seen here) is a smaller crater nicknamed 'Rimshot Crater.' The distance to this smaller crater, and the nearest portion of the rim of Big Crater, is 2200 meters (7200 feet). To the right of Big Crater, south from the spacecraft, almost lost in the atmospheric dust 'haze,' is the large streamlined mountain nicknamed 'Far Knob.' This mountain is over 450 meters (1480 feet) tall, and is over 30 kilometers (19 miles) from the spacecraft. Another, smaller and closer knob, nicknamed 'Southeast Knob' can be seen as a triangular peak to the left of the flanks of the Big Crater rim. This knob is 21 kilometers (13 miles) southeast from the spacecraft.

The larger features visible in this scene - Big Crater, Far Knob, and Southeast Knob - were discovered on the first panoramas taken by the IMP camera on the 4th of July, 1997, and subsequently identified in Viking Orbiter images taken over 20 years ago. The scene includes rocky ridges and swales or 'hummocks' of flood debris that range from a few tens of meters away from the lander to the distance of South Twin Peak. The largest rock in the nearfield, just left of center in the foreground, nicknamed 'Otter', is about 1.5 meters (4.9 feet) long and 10 meters (33 feet) from the spacecraft.

This view of Big Crater was produced by combining 6 individual 'Superpan' scenes from the left and right eyes of the IMP camera. Each frame consists of 8 individual frames (left eye) and 7 frames (right eye) taken with different color filters that were enlarged by 500% and then co-added using Adobe Photoshop to produce, in effect, a super-resolution panchromatic frame that is sharper than an individual frame would be.

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

1997-01-01

138

Coral Reef Ecosystems: Interdependence  

NSDL National Science Digital Library

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

National Science Teachers Association (NSTA)

2006-11-01

139

Bayesian Model Selection for LISA Pathfinder  

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

140

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

141

LISA Pathfinder interferometry: space hardware tests.  

NASA Astrophysics Data System (ADS)

The optical metrology system (OMS) onboard LISA Pathfinder must measure picometre test mass displacements in the millihertz frequency range. It comprises the Laser Assembly for light generation and modulation, the Optical Bench where the interferometry properly takes place and the Phasemeter and Data Management Unit for signal processing and control. During the past years the Albert-Einstein-Institute has developed an OMS test-bed where each subsystem can be integrated sequentially. This way we could perform various system level test campaigns in close collaboration with our industrial partners without waiting for the last subsystems to be delivered. The most important milestone has been the recent tests of the complete OMS at engineering model level, including the demonstration of the required sensitivity. Flight model tests of the Laser Assembly are good underway and OMS flight model tests are planned for the second half of this year.

Francisco Garca Marn, Antonio

142

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

143

Model Checking JAVA Programs Using Java Pathfinder  

NASA Technical Reports Server (NTRS)

This paper describes a translator called JAVA PATHFINDER from JAVA to PROMELA, the "programming language" of the SPIN model checker. The purpose is to establish a framework for verification and debugging of JAVA programs based on model checking. This work should be seen in a broader attempt to make formal methods applicable "in the loop" of programming within NASA's areas such as space, aviation, and robotics. Our main goal is to create automated formal methods such that programmers themselves can apply these in their daily work (in the loop) without the need for specialists to manually reformulate a program into a different notation in order to analyze the program. This work is a continuation of an effort to formally verify, using SPIN, a multi-threaded operating system programmed in Lisp for the Deep-Space 1 spacecraft, and of previous work in applying existing model checkers and theorem provers to real applications.

Havelund, Klaus; Pressburger, Thomas

2000-01-01

144

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

145

Mars Pathfinder airbag impact attenuation system  

SciTech Connect

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

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

1995-04-01

146

Mars Pathfinder/Global Surveyor Picturebook  

NSDL National Science Digital Library

Mars Pathfinder/Global Surveyor Picturebook is a Windows to the Universe Exploratour and provides information and images about the Martian landscape, the Rover, soils of Mars, dunes and wind, rocks, pebbles, clouds, sunsets, people involved with the Mission, and Martian geology. Windows to the Universe is a user-friendly learning system pertaining to the Earth and Space sciences. The objective of this project is to develop an innovative and engaging web site that spans the Earth and Space sciences and includes a rich array of documents, including images, movies, animations, and data sets that explore the Earth and Space sciences and the historical and cultural ties between science, exploration and the human experience. Links at the top of each page allow users to navigate between beginner, intermediate, and advanced options for each topic level.

Johnson, Roberta

2000-07-01

147

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

148

ReefBase: A Global Information System on Coral Reefs  

NSDL National Science Digital Library

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

Noordeloos, Machiel E.; Oliver, J.

149

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

150

Exopaleontology at The Pathfinder Landing Site  

NASA Technical Reports Server (NTRS)

The Mars Pathfinder Mission is a Discovery Class mission that will place a small lander and rover on the surface of Mars in July of 1997. It is primarily a technology demonstration to test the feasibility of a direct entry-delivery system, but carries a nominal scientific payload that includes rover-lander and instrumentation for limited mineralogical analysis. The nominal landing site was selected by the Pathfinder Team under the leadership of Dr. Matthew Golombek (JPL) based input from 60 participants at a Landing Site Workshop held last Spring at the Lunar Planetary Institute in Houston. The mission constraints for the landing site were 0-30 deg. N latitude, and below the 0.0 elevation datum. Over 20 landing sites were proposed and a nominal site was selected on southern Chryse Planitia near the terminae of the Ares and Tui outflow channels. In part, the decision to land at this location was based on the opportunity to sample a potentially large number lithologies in a small area (the rover will have a range of a few tens of meters from the lander). The purpose here is to review the general geological context of the landing site and the rationale for Exobiology's recommendation of the Ares site given at the workshop last spring. Because Ares and Tui Valles are sourced within terranes that may have originated by thermokarst processes, hydrothermal processes could have operated there for some time. Hydrothermal systems are presently regarded as important sites for a fossil record on Mars. Models for the formation of the outflow channels suggest that thermal spring sinters and associated aqueous mineral deposits, high priority targets for Mars Exopaleontology, could have formed in association with thermokarst processes and subsequently been delivered to the landing site in large quantities during the periodic cataclysmic outflows that created the channels.

Farmer, Jack D.; DesMarais, David J.; Greeley, Ronald; DeVincenzi, Donald L. (Technical Monitor)

1995-01-01

151

Exobiology site priorities for Mars Pathfinder  

NASA Astrophysics Data System (ADS)

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.; Des Marais, David J.

152

Degradation and recovery of Caribbean coral reefs  

E-print Network

reefs Coral reefs are facing global warming in addition toglobal warming, fishing appears to predate all other disturbances to coral reefs (Coral reefs have been increasingly degraded worldwide by overfishing, disease, pollution, and global warming (

Paredes, Gustavo Adolfo

2009-01-01

153

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

PubMed

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

Lough, Janice M

2008-01-01

154

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

155

Dust on Mars: Materials Adherence Experiment results from Mars Pathfinder  

SciTech Connect

Mars Pathfinder is the first solar-powered probe to operate on the surface of Mars. Pathfinder consists of a lander and a small, autonomous, six-wheel solar-powered rover, Sojourner. The Pathfinder spacecraft reflects NASA`s new philosophy of exploiting new technologies to reduce mission cost. The Materials Adherence Experiment on Pathfinder was designed to measure the degradation of solar arrays due to dust settling out of the atmosphere and blocking light to the solar array, lowering the array power output. The MAE measurements indicate steady dust accumulation at a rate of about 0.28% per day. This value is consistent with the performance of the solar arrays, which have decreased in power at an estimated rate of 0.29% per day.

Landis, G.A.; Jenkins, P.P. [NASA Lewis Research Center, Cleveland, OH (United States)

1997-12-31

156

Pathfinder aircraft taking off - setting new solar powered altitude record  

NASA Technical Reports Server (NTRS)

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

1995-01-01

157

PATH-FINDING FOR LARGE SCALE MULTIPLAYER COMPUTER GAMES  

Microsoft Academic Search

Path-finding consumes a significant amount of resources, especially in movement-intensive games such as (mas- sively) multiplayer games. We investigate several path- finding techniques, and explore the impact on perfor- mance of workloads derived from real player movements in a multiplayer game. We find that a map-conforming, hierarchical path-finding strategy performs best, and in combination with caching optimizations can greatly re-

Marc Lanctot; Clark Verbrugge

158

Amazing Reef: Moviemaker  

NSDL National Science Digital Library

In this movie-making interactive, learners can make an animated film about life on a coral reef. Learners choose an exciting story, cast colorful characters, and animate the movie themselves. They then add music and titles to complete the movie. Learners can even keep the movie by downloading it to their own computer. Learners can make up to four movies relating to survival, symbiosis, habitat, and predator/prey relationships in the Philippines Tropical Coral Reef.

Aquarium, Shedd; Educational Web Adventures (Eduweb)

2006-01-01

159

Spatial distribution of epibenthic molluscs on a sandstone reef in the Northeast of Brazil.  

PubMed

The present study investigated the distribution and abundance of epibenthic molluscs and their feeding habits associated to substrate features (coverage and rugosity) in a sandstone reef system in the Northeast of Brazil. Rugosity, low coral cover and high coverage of zoanthids and fleshy alga were the variables that influenced a low richness and high abundance of a few molluscan species in the reef habitat. The most abundant species were generalist carnivores, probably associated to a lesser offer and variability of resources in this type of reef system, when compared to the coral reefs. The results found in this study could reflect a normal characteristic of the molluscan community distribution in sandstone reefs, with low coral cover, or could indicate a degradation state of this habitat if it is compared to coral reefs, once that the significantly high coverage of fleshy alga has been recognized as a negative indicator of reef ecosystems health. PMID:22735136

Martinez, A S; Mendes, L F; Leite, T S

2012-05-01

160

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.

161

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

162

Reef classification by coral morphology predicts coral reef conservation value  

Microsoft Academic Search

Coral reefs can be classified using triangular diagrams based on coral morphology; these taxonomy-independent classes predict several aspects of conservation value for coral reefs. Conservation classes (CC's) of 1, 2, 3 or 4 were assigned to reef sites dominated by massive and submassive corals (CC 1), foliose or branching non-Acropora corals (CC 2), Acropora corals (CC 3), or approximately equal

Evan N Edinger; Michael J Risk

2000-01-01

163

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

164

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

165

Constellation Pathfinder: A University Nanosatellite Project  

NASA Astrophysics Data System (ADS)

Under the task of nanosatellite mission design, we developed a mission concept that enables hundreds of one-kilogram spacecraft to be placed into orbit with a single mothership. We performed trade studies to arrive at a positive feasibility assessment. The results of that study were described in two publications. Second, under the task of spacecraft design, we developed nanosatellite designs needed to enable constellation missions. Design studies were conducted and subsystems prototyped, including a spin-table and launcher concept for a small stack of nanosatellites. Engineering design studies of this work appeared in the refereed literature. Instruments to be flown on such a small craft have been specified and then developed as part of a related AF SBIR effort. Undergraduate students (>100 in the Aerospace Engineering, Mechanical Engineering, and Electrical and Computer Engineering departments) played an enormous role in the mission and spacecraft definitions of the Constellation Pathfinder project. In addition to five publications, numerous invited and contributed presentations of these studies have been presented at national and international meetings.

Spence, Harlan E.; Petschek, Harry E.

2002-08-01

166

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

167

Coral reef bleaching: ecological perspectives  

Microsoft Academic Search

Coral reef bleaching, the whitening of diverse invertebrate taxa, results from the loss of symbiotic zooxanthellae and\\/or a reduction in photosynthetic pigment concentrations in zooxanthellae residing within the gastrodermal tissues of host animals. Of particular concern are the consequences of bleaching of large numbers of reef-building scleractinian corals and hydrocorals. Published records of coral reef bleaching events from 1870 to

P. W. Glynn

1993-01-01

168

ReefBase: A Global Information System On Coral Reefs  

NSDL National Science Digital Library

ReefBase provides access to data and information on coral reefs and associated shallow tropical habitats. The site consists of three main sections: Reef Status, a Database, and the Users Area. Reef Status presents a compilation of summary reports pertaining to and indexed by global, regional, and national scales. Common topics in the reports include: reef benthos, reef fish, natural and anthropogenic threats, climate change impacts, marine protected areas, monitoring and management capacity, government policy, laws, and regulations, and author conclusions and recommendations for reef conservation. The Database provides for two sequential levels of searching: after a country or region is chosen, an overview provides general reef related information on that locale. The user can then further his/her search using one of three additional menus: Coral Reef, Protected Area, and Image/Map. The Coral Reef option currently returns basic information on nearly 10,000 reefs; in the future, additional information will address ecology, stresses, exploitation and management. The Protected Area option returns protections information largely compiled by the World Conservation Monitoring Centre. The third search option, Image/Map, returns visuals according to four criteria: Type (e.g., aerial, maps, underwater); Author; Stress (e.g., coastal development, oil pollution, siltation); or Lifeform (e.g., coralline algae, sea urchin, submassive). In addition, GIS data will soon be made available under this option. The final section on the site, the Users Area, provides both contact information and means of contributing to the site's contents.

169

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

170

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

171

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

172

Variation in emergence of parasitic and predatory isopods among habitats at Lizard Island, Great Barrier Reef  

Microsoft Academic Search

Gnathiid isopods are one of the most abundant groups of ectoparasites on coral reef fishes. They, and other isopods, have\\u000a been shown to significantly affect the health and behaviour of many reef fish. Whether isopod emergence differs among habitats\\u000a on coral reefs is not known. In this study, we measured emergence rates of parasitic isopods (Gnathiidea and Flabellifera)\\u000a in six

C. M. Jones; A. S. Grutter

2007-01-01

173

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.

174

Coral reef resilience through biodiversity  

USGS Publications Warehouse

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

Rogers, Caroline S.

2013-01-01

175

The evolution of reef communities  

SciTech Connect

This book discusses the composition, structure, occurrence, and changes in reefs during the past 2 billion years. It emphasizes the functional roles of major groups (guilds) of reef-building, reef-destroying, and reed-dwelling organisms in the most complex of all marine communities. A structural model, based on modern reef guilds, is developed. Then the functional roles of each major reef-building higher biologic taxon (algae, sponges, coral, etc.) is determined, and, on this basis, each such taxon is assigned to a reef community guild. Next, the authors traces the geologic history and guild assignment of each major taxon through geologic time. The final chapter establishes a succession of ten major reef community types, and considers their extinction and recovery in the light of modern theories of cosmic and earthly events.

Fagerstrom, J.A.

1987-01-01

176

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

177

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

178

Mars Pathfinder Rover-Lewis Research Center Technology Experiments Program  

NASA Technical Reports Server (NTRS)

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

Stevenson, Steven M.

1997-01-01

179

The Semantic Pathfinder: Using an Authoring Metaphor for Generic Multimedia Indexing  

Microsoft Academic Search

This paper presents the semantic pathfinder architecture for generic indexing of multimedia archives. The semantic pathfinder extracts semantic concepts from video by exploring different paths through three consecutive analysis steps, which we derive from the observation that produced video is the result of an authoring-driven process. We exploit this authoring metaphor for machine-driven understanding. The pathfinder starts with the content

Cees Snoek; Marcel Worring; Jan-mark Geusebroek; Dennis Koelma; Frank J. Seinstra; Arnold W. M. Smeulders

2006-01-01

180

Sewage impacts coral reefs at multiple levels of ecological organization.  

PubMed

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

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

2009-09-01

181

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

PubMed

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

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

2014-12-01

182

PATHFINDER: Probing Atmospheric Flows in an Integrated and Distributed Environment  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

183

Rivers, runoff, and reefs  

USGS Publications Warehouse

The role of terrigenous sediment in controlling the occurrence of coral reef ecosystems is qualitatively understood and has been studied at local scales, but has not been systematically evaluated on a global-to-regional scale. Current concerns about degradation of reef environments and alteration of the hydrologic and sediment cycles place the issue at a focal point of multiple environmental concerns. We use a geospatial clustering of a coastal zone database of river and local runoff identified with 0.5?? grid cells to identify areas of high potential runoff effects, and combine this with a database of reported coral reef locations. Coastal cells with high runoff values are much less likely to contain reefs than low runoff cells and GIS buffer analysis demonstrates that this inhibition extends to offshore ocean cells as well. This analysis does not uniquely define the effects of sediment, since salinity, nutrients, and contaminants are potentially confounding variables also associated with runoff. However, sediment effects are likely to be a major factor and a basis is provided for extending the study to higher resolution with more specific variables. ?? 2003 Elsevier B.V. All rights reserved.

McLaughlin, C. J.; Smith, C. A.; Buddemeier, R. W.; Bartley, J. D.; Maxwell, B. A.

2003-01-01

184

CORAL REEF BIOCRITERIA  

EPA Science Inventory

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

185

Reefs since Columbus  

Microsoft Academic Search

History shows that Caribbean coastal ecosystems were severely degraded long before ecologists began to study them. Large vertebrates such as the green turtle, hawksbill turtle, manatee and extinct Caribbean monk seal were decimated by about 1800 in the central and northern Caribbean, and by 1990 elsewhere. Subsistence over-fishing subsequently decimated reef fish populations. Local fisheries accounted for a small fraction

J. B. C. Jackson

1997-01-01

186

The Barrier Reef sediment apron: Tobacco Reef, Belize  

NASA Astrophysics Data System (ADS)

Sedimentological and biological surveys of the back-reef sediment apron of Tobacco Reef, a continuous segment of the Belizean Barrier Reef, reveal five distinct biogeological zones: (1) coralline-coral- Dictyota pavement, (2) Turbinaria-Sargassum rubble, (3) Laurencia-Acanthophora sand and gravel, (4) bare sand and 95 Thalassia sand. These zones parallel the entire 9-km reef. The distribution of these zones is related to the spatial patterns of fish herbivory, the size of bottom sediments, and the stability of the substrate. Sedimentological and hydrodynamic studies indicate that most of the sediments in this area are transported from the reef crest and fore reef during periods of storm or hurricane activity and that their size distribution is largely the result of differential transport by high bottom-water velocities during those periods.

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

1987-07-01

187

Ecological intereactions of reef building corals  

EPA Science Inventory

Coral reefs are very important marine ecosystems because they support tremendous biodiversity and reefs are critical economic resources many coastal nations. Tropical reef structures are largely built by stony corals. This presentation provides background on basic coral biology t...

188

Horizontal mixing of Great Barrier Reef waters: Offshore diffusivity determined from radium isotope distribution  

Microsoft Academic Search

The Great Barrier Reef (GBR), northern Australia, is the largest coral reef system in the world and provides habitat for highly diverse tropical marine ecosystems. Mixing in the coastal waters of the GBR is an important parameter influencing the health of these ecosystems. We have used the distribution of the four naturally occurring radium isotopes to determine the rate of

Gary J. Hancock; Ian. T. Webster; Thomas C. Stieglitz

2006-01-01

189

Coral Reef Protection: A Watershed Approach  

NSDL National Science Digital Library

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

190

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

191

Pathfinders for Four Directions: An Indigenous Educational Model.  

ERIC Educational Resources Information Center

The Four Directions Project, administered by the Pueblo of Laguna Department of Education, is a 5-year federally-funded technology innovation grant that aims to help Native people and their educators develop culturally relevant curricula through technology. This report includes the full text of 45 "pathfinders" designed by students in the Graduate

Roy, Loriene, Comp.

192

NASA's Pathfinder data set programme: land surface parameters  

Microsoft Academic Search

The Pathfinder data set concept was initiated by the Earth Observing System (EOS) Program Office at the National Aeronautics and Space Administration (NASA) Headquarters to address how existing satellite-derived data sets could be used for global change research prior to the availability of EOS data. They are denned as long time-series satellite data sets capable of stable calibration which can

M. E. Maiden; S. Greco

1994-01-01

193

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

194

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

195

International Society for Reef Studies  

NSDL National Science Digital Library

Located within the Florida Institute of Technology, the International Society for Reef Studies (ISRS) was founded in 1980, and is designed to disseminate its findings on both living and fossil coral reefs to fellow scholars around the globe and the general public. Before delving into the main site, visitors will want to look through the ISRS in-house publication "Reef Encounters" to get a sense of the various projects the organization is currently working on, and of course, to read brief summaries of its research findings. Of course, for those who already are passionate about coral reefs, there is also a link to sign up for the NOAA "Coral List" forum. The resources section of the site is another good place to look for outside Web resources on other coral reef societies, marine laboratories, and government sites that contain materials on coral reefs and marine biology.

196

Spatial Resilience of Coral Reefs  

Microsoft Academic Search

There have been several earlier studies that addressed the influence of natural disturbance regimes on coral reefs. Humans\\u000a alter natural disturbance regimes, introduce new stressors, and modify background conditions of reefs. We focus on how coral\\u000a reef ecosystems relate to disturbance in an increasingly human-dominated environment. The concept of ecosystem resiliencethat\\u000a is, the capacity of complex systems with multiple stable

Magnus Nystrm; Carl Folke

2001-01-01

197

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

198

Remote sensing of coral reefs and their physical environment.  

PubMed

There has been a vast improvement in access to remotely sensed data in just a few recent years. This revolution of information is the result of heavy investment in new technology by governments and industry, rapid developments in computing power and storage, and easy dissemination of data over the internet. Today, remotely sensed data are available to virtually anyone with a desktop computer. Here, we review the status of one of the most popular areas of marine remote sensing research: coral reefs. Previous reviews have focused on the ability of remote sensing to map the structure and habitat composition of coral reefs, but have neglected to consider the physical environment in which reefs occur. We provide a holistic review of what can, might, and cannot be mapped using remote sensing at this time. We cover aspects of reef structure and health but also discuss the diversity of physical environmental data such as temperature, winds, solar radiation and water quality. There have been numerous recent advances in the remote sensing of reefs and we hope that this paper enhances awareness of the diverse data sources available, and helps practitioners identify realistic objectives for remote sensing in coral reef areas. PMID:14972573

Mumby, Peter J; Skirving, William; Strong, Alan E; Hardy, John T; LeDrew, Ellsworth F; Hochberg, Eric J; Stumpf, Rick P; David, Laura T

2004-02-01

199

Results of the Imager for Mars Pathfinder windsock experiment  

NASA Astrophysics Data System (ADS)

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.

Sullivan, Robert; Greeley, Ronald; Kraft, Michael; Wilson, Gregory; Golombek, Matthew; Herkenhoff, Ken; Murphy, James; Smith, Peter

2000-10-01

200

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.

201

Digital reef rugosity estimates coral reef habitat complexity.  

PubMed

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

202

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

203

Reef Environmental Education Foundation  

NSDL National Science Digital Library

Contains information on REEF, an organization devoted to preserving marine life through education, research and involvement. It includes a fish gallery with images and information on a variety of tropical fish. Membership provides reduced-cost dive trips all over the world to conduct observational research while diving. New data is added daily from volunteers world-wide and is available for download for classroom activities.

204

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 mol kg?1 and DIC concentrations ranged from 1846 to 2099 mol kg?1. This resulted in pCO2 concentrations from 340 to 554 atm, 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 atm 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; L?nborg, Christian

2014-01-01

205

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 mol kg-1 and DIC concentrations ranged from 1846 to 2099 mol kg-1. This resulted in pCO2 concentrations from 340 to 554 atm, 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 atm 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; Lnborg, Christian

2014-01-01

206

Analyzing Pathfinder data using virtual reality and superresolved imaging  

NASA Astrophysics Data System (ADS)

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

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

1999-04-01

207

Black reefs: iron-induced phase shifts on coral reefs  

PubMed Central

The Line Islands are calcium carbonate coral reef platforms located in iron-poor regions of the central Pacific. Natural terrestrial run-off of iron is non-existent and aerial deposition is extremely low. However, a number of ship groundings have occurred on these atolls. The reefs surrounding the shipwreck debris are characterized by high benthic cover of turf algae, macroalgae, cyanobacterial mats and corallimorphs, as well as particulate-laden, cloudy water. These sites also have very low coral and crustose coralline algal cover and are call black reefs because of the dark-colored benthic community and reduced clarity of the overlying water column. Here we use a combination of benthic surveys, chemistry, metagenomics and microcosms to investigate if and how shipwrecks initiate and maintain black reefs. Comparative surveys show that the live coral cover was reduced from 40 to 60% to <10% on black reefs on Millennium, Tabuaeran and Kingman. These three sites are relatively large (>0.75?km2). The phase shift occurs rapidly; the Kingman black reef formed within 3 years of the ship grounding. Iron concentrations in algae tissue from the Millennium black reef site were six times higher than in algae collected from reference sites. Metagenomic sequencing of the Millennium Atoll black reef-associated microbial community was enriched in iron-associated virulence genes and known pathogens. Microcosm experiments showed that corals were killed by black reef rubble through microbial activity. Together these results demonstrate that shipwrecks and their associated iron pose significant threats to coral reefs in iron-limited regions. PMID:21881615

Kelly, Linda Wegley; Barott, Katie L; Dinsdale, Elizabeth; Friedlander, Alan M; Nosrat, Bahador; Obura, David; Sala, Enric; Sandin, Stuart A; Smith, Jennifer E; Vermeij, Mark J A; Williams, Gareth J; Willner, Dana; Rohwer, Forest

2012-01-01

208

Black reefs: iron-induced phase shifts on coral reefs.  

PubMed

The Line Islands are calcium carbonate coral reef platforms located in iron-poor regions of the central Pacific. Natural terrestrial run-off of iron is non-existent and aerial deposition is extremely low. However, a number of ship groundings have occurred on these atolls. The reefs surrounding the shipwreck debris are characterized by high benthic cover of turf algae, macroalgae, cyanobacterial mats and corallimorphs, as well as particulate-laden, cloudy water. These sites also have very low coral and crustose coralline algal cover and are call black reefs because of the dark-colored benthic community and reduced clarity of the overlying water column. Here we use a combination of benthic surveys, chemistry, metagenomics and microcosms to investigate if and how shipwrecks initiate and maintain black reefs. Comparative surveys show that the live coral cover was reduced from 40 to 60% to <10% on black reefs on Millennium, Tabuaeran and Kingman. These three sites are relatively large (>0.75 km(2)). The phase shift occurs rapidly; the Kingman black reef formed within 3 years of the ship grounding. Iron concentrations in algae tissue from the Millennium black reef site were six times higher than in algae collected from reference sites. Metagenomic sequencing of the Millennium Atoll black reef-associated microbial community was enriched in iron-associated virulence genes and known pathogens. Microcosm experiments showed that corals were killed by black reef rubble through microbial activity. Together these results demonstrate that shipwrecks and their associated iron pose significant threats to coral reefs in iron-limited regions. PMID:21881615

Kelly, Linda Wegley; Barott, Katie L; Dinsdale, Elizabeth; Friedlander, Alan M; Nosrat, Bahador; Obura, David; Sala, Enric; Sandin, Stuart A; Smith, Jennifer E; Vermeij, Mark J A; Williams, Gareth J; Willner, Dana; Rohwer, Forest

2012-03-01

209

Coral reef collapse spells danger for millions Island communities that depend on coral reef  

E-print Network

Coral reef collapse spells danger for millions Island communities that depend on coral reef (Canada), published in Current Biology. The report on island coral reef fisheries reveals that 55pc of coral reef would be needed ­ an area 3.7 times greater than Australia's Great Barrier Reef (pictured

Feigon, Brooke

210

AAAS Feb `04 Frontiers in Coral Reef Research Climate Change and Coral Reefs  

E-print Network

AAAS Feb `04 Frontiers in Coral Reef Research Climate Change and Coral Reefs Joan A. Kleypas University of Kansas Lawrence, KS EARTH SeaWiFS image from: Orbimage #12;AAAS Feb `04 Frontiers in Coral Reef Feb `04 Frontiers in Coral Reef Research Effects of CO2 on Coral Reefs Reduced [CO3 2-] Increased

Kleypas, Joanie

211

Can artificial reefs mimic natural reef communities? The roles of structural  

E-print Network

Abstract In light of the deteriorating state of coral reefs worldwide, the need to rehabilitate marine environments has greatly increased. Artificial reefs (ARs) have been suggested as a tool for reef conservation development; Spatial orientation; Structural complexity; Coral reef; Red Sea 1. Introduction Coral reefs

Benayahu, Yehuda

212

Perspectives in coral reef hydrodynamics  

NASA Astrophysics Data System (ADS)

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

Hearn, Clifford J.

2011-06-01

213

Confronting the coral reef crisis  

Microsoft Academic Search

The worldwide decline of coral reefs calls for an urgent reassessment of current management practices. Confronting large-scale crises requires a major scaling-up of management efforts based on an improved understanding of the ecological processes that underlie reef resilience. Managing for improved resilience, incorporating the role of human activity in shaping ecosystems, provides a basis for coping with uncertainty, future changes

T. P. Hughes; C. Folke; M. Nystrm; D. R. Bellwood

2004-01-01

214

Keeping Watch on Coral Reefs  

NSDL National Science Digital Library

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

Education, Noaa O.

215

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

216

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.

217

First light of the LINC-NIRVANA Pathfinder experiment  

NASA Astrophysics Data System (ADS)

The LINC-NIRVANA Pathfinder experiment is a test-bed to verify a very complex sub-system: the Ground-layer Wavefront Sensor, or GWS. Pathfinder will test the GWS in its final working environment and demonstrate on-sky the performance achievable with a multiple natural guide star, ground-layer adaptive optics system with a very wide FoV. The GWS uses up to 12 natural guide stars within a 2.8'-6' annular field of view and drives the LBT adaptive secondary mirror to correct the lower layers of atmospheric turbulence. This paper will trace the path of the instrument on its way to First Light on-sky in November 2013, from its installation on the telescope to the calibrations to its final operation, focusing in particular on opto-mechanical and software aspects and how they lead to the main achieved results.

Bergomi, M.; Viotto, V.; Arcidiacono, C.; Marafatto, L.; Farinato, J.; Baumeister, H.; Bertram, T.; Berwein, J.; Briegel, F.; Conrad, A.; Kittman, F.; Kopon, D.; Hofferbert, R.; Magrin, D.; Radhakrishnan Santhakumari, K. K.; Puglisi, A.; Xompero, M.; Briguglio, R.; Quiros-Pacheco, F.; Herbst, T. M.; Ragazzoni, R.

2014-07-01

218

Images from Mars Pathfinder - Data Processing Techniques Revisited  

NASA Astrophysics Data System (ADS)

The primary goal of the Mars Pathfinder Mission was the development of a low cost system that could place a science payload on the Martian surface. Landing on July 4 and operating through September 27, 1997 the mission returned 2,6 GB of data, including over 16,000 images by the IMP (Image for Mars Pathfinder) mounted on top of the lander and 550 images of the rover camera. To support geologists in their analysis we applied and adopted photogrammetric techniques to map the lander area, to determine the landers coordinates in a global context, and to orientate the images with respect to the North direction. With the upcoming activities in Europe in the context of the Exomars mission as well al Planetary Rover Vision projects, we will report on our experience with IMP image data and discuss the processing methods and techniques that were applied.

Willner, K.; Oberst, J.; Scholten, F.; Jaumann, R.

2008-09-01

219

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

220

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

221

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 Agencys 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

222

True Color of Mars - Pathfinder Sol 39 Sunrise  

NASA Technical Reports Server (NTRS)

Sunrise, sol 39. This true color, pre-sunrise image (approximately 0530LST) is composed of six images extending 30 o in azimuth and 45 o in elevation and shows the brownish gray predawn sky. A description of the techniques used to generate this color image from IMP data can be found in Maki et al., 1999. Note: a calibrated output device is required accurately reproduce the correct colors.

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

1999-01-01

223

JPL Experience with the Mars Pathfinder, Mission Simulation Battery  

NASA Technical Reports Server (NTRS)

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

Perrone, Dave; Ewell, Richard

1997-01-01

224

The LTP Experiment on the LISA Pathfinder Mission  

E-print Network

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

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

2005-01-01

225

The LTP Experiment on the LISA Pathfinder Mission  

E-print Network

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

S. Vitale

2005-04-14

226

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.

227

The International Coral Reef Information Network  

NSDL National Science Digital Library

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

International Coral Reef Action Network (ICRAN)

228

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

Microsoft Academic Search

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

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

229

MOC's Highest Resolution View of Mars Pathfinder Landing Site  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] (A) Mars Pathfinder site, left: April 1998; right: January 2000.

[figure removed for brevity, see original site] (B) top: April 1998; bottom: January 2000.

Can Mars Global Surveyor's 1.5 meter (5 ft) per pixel camera be used to find any evidence as to the fate of the Mars Polar Lander that was lost on December 3, 1999? One way to find out is to look for one of the other Mars landers and determine what, if anything, can be seen. There have been three successful Mars lander missions: Viking 1 (July 1976), Viking 2 (September 1976), and Mars Pathfinder (July 1997). Of these, the location of Mars Pathfinder is known the best because there are several distinct landmarks visible in the lander's images that help in locating the spacecraft. The MGS MOC Operations Team at Malin Space Science Systems has been tasked since mid-December 1999 with looking for the lost Polar Lander. Part of this effort has been to test the capabilities of MOC by taking a picture of the landing site of Mars Pathfinder.

An attempt to photograph the Pathfinder site was made once before, in April 1998, by turning the entire MGS spacecraft so that the camera could point at the known location of the Mars Pathfinder lander. Turning the MGS spacecraft like this is not a normal operation--it takes considerable planning, and disrupts the on-going, normal acquisition of science data. It took 3 attempts to succeed, but on April 22, 1998, MOC acquired the picture seen on the left side of Figure A, above. The three near-by major landmarks that were visible to the Pathfinder's cameras are labeled here (North Peak, Big Crater, Twin Peaks). It was known at the time that this image was not adequate to see the Pathfinder lander because the camera was not in focus and had a resolution of only 3.3 meters (11 ft) per pixel. In this and all other images shown here, north is up. All views of the 1998 MOC image are illuminated from the lower right, all views of the 2000 MOC image are illuminated from the lower left.

As part of the Polar Lander search effort, the Mars Pathfinder site was targeted again in December 1999 and January 2000. Like the 1998 attempt, the spacecraft had to be pointed off of its normal, nadir (straight-down) view. Like history repeating itself, it once again took 3 tries before the Pathfinder landing site was hit. The picture on the right side of Figure A, above, shows the new image that was acquired on January 16, 2000. The white box indicates the location shown in Figure B (above, right). The 1000 m scale bar equals 0.62 miles.

Figure B (above) shows a subsection of both the 1998 image (top, labeled SPO-1-25603) and the 2000 image (bottom, labeled m11-2414) projected at a scale of 3 meters (10 ft) per pixel. At this scale, the differences in camera focus and sunlight illumination angle are apparent, with the January 2000 image being both in focus and having better lighting conditions. In addition, the MGS spacecraft took the 2000 image from a lower altitude than in 1998, thus the image has better spatial resolution overall. The 500 m scale bar is equal to about 547 yards. The white box shows the location of images in Figure C, below.

[figure removed for brevity, see original site] (C) higher-resolution view; left: April 1998; right: January 2000.

[figure removed for brevity, see original site] D) Erroneous, preliminary identification of Mars Pathfinder location in January 2000 image. Subsequent analysis (Figures E & F, below) identified the correct spot.

The third figure (C, above) again shows portions of the April 1998 image (C, left) and January 2000 image (C, right), only this time they have been enlarged to a resolution of 0.75 meters (2.5 ft) per pixel. The intrinsic resolution of the January 2000 image is 1.5 meters (5 ft), so this is a 200% expanded view of the actual M11-02414 image. The circular features in this and the previous images are impact craters in various states of erosion. Some boulders (dark dots) ca

2000-01-01

230

Expeditions in Conservation: Mesoamerican Reef  

NSDL National Science Digital Library

The World Wildlife Fund (WWF) recently completed this expedition of the largest coral reef system in the Atlantic Ocean and has provided an opportunity for Web users to share some of what they experienced. Visitors can view spectacular photos and videos to learn about the reef and the creatures that reside there, as well as read the daily reports of the expedition. The site offers much more in terms of learning about coral reefs, the people who study them, and the threats that face these unique ecosystems.

1969-12-31

231

Age of tilted reefs, Hawaii.  

USGS Publications Warehouse

Submerged carbonate reefs are preserved as a series of submarine terraces between Molokai and Hawaii along a 200-km span of the SE Hawaiian Ridge. Limestones from 2 of the terraces have been dated at 13 and 120 ka. Recognition that the terraces are tilted permits assignment of about a dozen terraces from 150 to 1300 m depth to 8 general reef platforms. These reefs were drowned by the combined effects of island subsidence and sea level rise at the end of successive glacial stages from 13 to 647 ka. The platforms are tilted 5 m/km SE toward the locus of volcanic centered on the island of Hawaii.-from Authors

Moore, J. G.; Campbell, J. F.

1987-01-01

232

Bermuda's Southern Aeolianite Reef Tract.  

PubMed

The outer reef on the explored southeast margin of the Bermuda platform is a submerged dune ridge thinly veneered with encrusting organisms. Aeolianites were deposited on what appears to be an older truncated surface, the reef-front terrace, now submerged to a depth of about 18 meters. Underwater examination reveals relict features of probable solutional origin that honeycomb the aeolinite and that have undergone only minor modification by erosion since the last eustatic rise of the sea. Submarine planation, even in this marginal area of reef growth, is a relatively slow process. PMID:17792849

Stanley, D J; Swift, D J

1967-08-11

233

Predicting the impact of present and future human land-use on the Great Barrier Reef  

NASA Astrophysics Data System (ADS)

An ecohydrologic model, verified against field data, suggests that land-use has contributed to degradation of the health of the Great Barrier Reef and to an increased frequency and intensity of crown-of-thorns starfish infestations. The model also predicts that the health of the Great Barrier Reef will significantly worsen by the year 2050 as a result of global warming. However, the model also suggests that much-improved land-use practices will enable some regions of the Great Barrier Reef to recover, even with global warming. Finally, the model suggests that, if global warming proceeds unchecked, biological adaptation is necessary to avoid a collapse of the Great Barrier Reef health by the year 2100.

Wolanski, Eric; De'ath, Glenn

2005-08-01

234

Commencement on a Coral Reef  

ERIC Educational Resources Information Center

Describes an environmental program in which sixteen students and three biology teachers from Northfield Mount Hermon School in Massachusetts spent two weeks examining the ecology of a Caribbean reef.. (JR)

Webster, Steven K.

1973-01-01

235

Lab 3: Building a Reef  

NSDL National Science Digital Library

During this lab, students learn about the life cycle of corals, including how they grow and reproduce. Students consider the chemistry of seawater and the importance of the symbiotic relationship between corals and zooxanthellae in the formation of coral reefs. They blow CO2 through calcium hydroxide (limewater) to model how respiration assists coral in precipitating calcium carbonate. Students also build on the coral polyp models they made in Lab 2 to demonstrate coral growth, reproduction, and reef formation.

236

Pathfinder: The Geospatial Intelligence Magazine Serving the Front Line, March/April 2009. Volume 7, Number 2.  

National Technical Information Service (NTIS)

The Pathfinder is the medium with which the National Geospatial- Intelligence Agency enhances and promotes public awareness and understanding of the discipline of geospatial intelligence. The Pathfinder is an authorized Department of Defense publication f...

A. Higgins, C. Montenegro, D. Carey, D. Ellenberger, S. Chang

2009-01-01

237

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

238

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

NASA Technical Reports Server (NTRS)

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

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

1998-01-01

239

The Data Processor of the JEM-EUSO pathfinders  

NASA Astrophysics Data System (ADS)

JEM-EUSO is a wide-angle refractive UV telescope being proposed for attachment to the Japanese Experiment Module on ISS. The main goal of the mission is to study Extreme Energy Cosmic Rays. Two pathfinder mission are now in progress: EUSO-TA and EUSO-Balloon. The EUSO-TA project foresees the installation of a telescope prototype in the Telescope Array site. The aim of this project is to calibrate the telescope with the TA fluorescence detector. An initial run of one year starting from 2013 is foreseen. EUSO-Balloon is a pathfinder mission in which a prototype telescope will be mounted on a stratospheric balloon. The main aim of this mission is to perform a end-to-end test of all the key technologies and instrumentation of JEM-EUSO detectors and to prove the global detection chain. EUSO-Balloon will measure the UV background fundamental for the development of the simulations. EUSO-Balloon has the potential to detect Extensive Air Showers from above, paving the way for any future space-based EECR observatory. We will present the Data Processor of the pathfinders. The DP is the component of the Electronics System which performs data management and instrument control. The DP controls front-end electronics, performs 2nd level trigger filtering, tags events with arrival time and payload position through a GPS system, manages mass memory for data storage, measures live and dead time of the telescope, provides signals for time synchronization of the event, performs housekeeping monitor and handles interface to the telemetry system. We will describe the main components of the DP, the state-of-the-art and the results of the tests carried out.

Scotti, V.; Osteria, G.

2014-06-01

240

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

NASA Astrophysics Data System (ADS)

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

Diedrich, A.

2007-12-01

241

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

Microsoft Academic Search

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

Larry McMurchie; Carl Ebeling

1995-01-01

242

Closed loop simulations of the thermal experiments in LISA Pathfinder  

E-print Network

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

Ferran Gibert; Miquel Nofrarias; Nikolaos Karnesis; Marc Daz-Aguil; Ignacio Mateos; Alberto Lobo; Llus Gesa; Vctor Martn; Ivan Lloro

2013-12-11

243

ER-20037 LLNL eternal pathfinder wing spar design study report  

SciTech Connect

This document outlines the results of a design study performed by EDO-FSD on the LLNL Eternal Pathfinder Wing Spar/Fuel Tank. The main focus of the design study was the weight minimization of the composite wall of the mid span spar section of the aircraft. The torque, shear, moment and pressure loading requirements, as well as LLNL`s preliminary drawings, were used to develop a reduced weight mid-span spar design. The design study also encompassed details such as the pressure bulkheads, wing rod connectors, and attachment flanges.

Not Available

1994-03-01

244

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

245

Closed Loop Simulations of the Thermal Experiments in LISA Pathfinder  

NASA Astrophysics Data System (ADS)

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

Gibert, F.; Nofrarias, M.; Karnesis, N.; Daz-Aguil, M.; Mateos, I.; Lobo, A.; Gesa, L.; Martn, V.; Lloro, I.

2013-01-01

246

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

247

Miocene precursors to Great Barrier Reef  

SciTech Connect

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

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

1988-01-01

248

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

249

Response of coral reefs to climate change: Expansion and demise of the southernmost Pacific coral reef  

Microsoft Academic Search

Coral reefs track sea level and are particularly sensitive to changes in climate. Reefs are threatened by global warming, with many experiencing increased coral bleaching. Warmer sea surface temperatures might enable reef expansion into mid latitudes. Here we report multibeam sonar and coring that reveal an extensive relict coral reef around Lord Howe Island, which is fringed by the southernmost

Colin D. Woodroffe; Brendan P. Brooke; Michelle Linklater; David M. Kennedy; Brian G. Jones; Cameron Buchanan; Richard Mleczko; Quan Hua; Jian-xin Zhao

2010-01-01

250

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

251

Reef Odor: A wake up call for navigation in reef fish larvae --Manuscript Draft--  

E-print Network

-ocean; swimming speed; orientation; behavioral arena; chemical cues; tidal current; Great Barrier Reef; drifting, were observed in the two water masses around One Tree Island, southern Great Barrier Reef. The studyPLOS ONE Reef Odor: A wake up call for navigation in reef fish larvae --Manuscript Draft

Paris-Limouzy, Claire B.

252

Response of coral reefs to climate change: Expansion and demise of the southernmost Pacific coral reef  

NASA Astrophysics Data System (ADS)

Coral reefs track sea level and are particularly sensitive to changes in climate. Reefs are threatened by global warming, with many experiencing increased coral bleaching. Warmer sea surface temperatures might enable reef expansion into mid latitudes. Here we report multibeam sonar and coring that reveal an extensive relict coral reef around Lord Howe Island, which is fringed by the southernmost reef in the Pacific Ocean. The relict reef, in water depths of 25-50 m, flourished in early Holocene and covered an area more than 20 times larger than the modern reef. Radiocarbon and uranium-series dating indicates that corals grew between 9000 and 7000 years ago. The reef was subsequently drowned, and backstepped to its modern limited extent. This relict reef, with localised re-establishment of corals in the past three millennia, could become a substrate for reef expansion in response to warmer temperatures, anticipated later this century and beyond, if corals are able to recolonise its surface.

Woodroffe, Colin D.; Brooke, Brendan P.; Linklater, Michelle; Kennedy, David M.; Jones, Brian G.; Buchanan, Cameron; Mleczko, Richard; Hua, Quan; Zhao, Jian-xin

2010-08-01

253

A Night in the Coral Reef  

NSDL National Science Digital Library

Coral reefs are often portrayed as brightly lit, bustling underwater marvels full of colorful creatures. This video segment, adapted from NOVA, paints a different picture as it explores the nocturnal behavior of organisms in the reef.

Foundation, Wgbh E.

2007-04-19

254

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

255

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 20S\\u000a and 23S. Major reef

R. van Woesik; T. J. Done

1997-01-01

256

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

257

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

258

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

259

Mars Pathfinder and Mars Global Surveyor Outreach Compilation  

NASA Astrophysics Data System (ADS)

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

1999-09-01

260

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

261

PHOSPHATE METABOLISM OF CORAL REEF FLATS  

E-print Network

PHOSPHATE METABOLISM OF CORAL REEF FLATS A DISSERTATION SUBMITTED TO THE GRADUATE DIVISION. Chave Edward A. Laws David M. Karl Robert L. Fox #12;iv ABSTRACT Ihe present dogma on coral reef overlying that community. The reef's nutritional requirements supposedly are met by cycling or retention

Luther, Douglas S.

262

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

263

REEF fXSHXHQ FISHERY LEAFLET 354  

E-print Network

glance at a chart of the waters of the Philippines will reveal the great extent of the coral reefs mile from the shore. Barrier reefs occur rather sparingly in the Philippines. They are exemplifiedw REEF fXSHXHQ FISHERY LEAFLET 354 FISH AND WILDLIFE SERVICE United States Department

264

The Pros and Cons of Artificial Reefs  

NSDL National Science Digital Library

This lesson plan asks students to consider whether artificial reefs (human-made objects in the ocean or sea) are good for marine ecosystems. Students will look at pictures of artificial reefs and read articles describing the pros and cons of these structures. They will conclude by writing paragraphs explaining whether they think a new artificial reef should be created in Florida waters.

265

40 CFR 230.44 - Coral reefs.  

... 25 2014-07-01 2014-07-01 false Coral reefs. 230.44 Section 230.44 Protection of...Impacts on Special Aquatic Sites 230.44 Coral reefs. (a) Coral reefs consist of the skeletal deposit, usually...

2014-07-01

266

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

267

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

268

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

269

Private development of artificial reefs  

E-print Network

fisheries are held and con- sistent with state and federal law, and; (3) that the pri- vate development of artificial reefs in concert with a char- ter boat business is a financially feasible operation. For the purposes of this thesis the definition... fisheries are held and con- sistent with state and federal law, and; (3) that the pri- vate development of artificial reefs in concert with a char- ter boat business is a financially feasible operation. For the purposes of this thesis the definition...

Burns, Arthur Allen

2012-06-07

270

Geomorphology and community structure of Middle Reef, central Great Barrier Reef, Australia: an inner-shelf turbid zone reef subject to episodic mortality events  

Microsoft Academic Search

Middle Reef is an inshore turbid zone reef located 4km offshore from Townsville, Queensland, Australia. The reef consists\\u000a of four current-aligned, interconnected reef patches that have reached sea level and formed reef flats. It is regularly exposed\\u000a to high turbidity (up to 50mgl?1) generated by wave-driven sediment resuspension or by episodic flood plumes. Middle Reef has a high mean hard

N. K. Browne; S. G. Smithers; C. T. Perry

2010-01-01

271

Subterranean Groundwater Nutrient Input to Coastal Oceans and Coral Reef Sustainability  

NASA Astrophysics Data System (ADS)

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

Paytan, A.; Street, J. H.

2003-12-01

272

Exploring MEDLINE Space with Random Indexing and Pathfinder Networks  

PubMed Central

The integration of disparate research domains is a prerequisite for the success of the translational science initiative. MEDLINE abstracts contain content from a broad range of disciplines, presenting an opportunity for the development of methods able to integrate the knowledge they contain. Latent Semantic Analysis (LSA) and related methods learn human-like associations between terms from unannotated text. However, their computational and memory demands limits their ability to address a corpus of this size. Furthermore, visualization methods previously used in conjunction with LSA have limited ability to define the local structure of the associative networks LSA learns. This paper explores these issues by (1) processing the entire MEDLINE corpus using Random Indexing, a variant of LSA, and (2) exploring learned associations using Pathfinder Networks. Meaningful associations are inferred from MEDLINE, including a drug-disease association undetected by PUBMED search. PMID:18999236

Cohen, Trevor

2008-01-01

273

Soil-like deposits observed by Sojourner, the Pathfinder rover  

USGS Publications Warehouse

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

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

1999-01-01

274

Classification of Mars Pathfinder Rock Surfaces Using Quantitative Morphologic Indices  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

275

Acquiring multiple stars with the LINC-NIRVANA Pathfinder  

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

276

Dust devil vortices seen by the Mars Pathfinder camera  

USGS Publications Warehouse

Discovery of dust devil vortices in Mars Pathfinder (MPF) images reveals a dust entrainment mechanism at work on Mars. Scattering of visible light by dust in the Martian atmosphere creates a pronounced haze, preventing conventional image processing from displaying dust plumes. Spectral differencing techniques have enhanced five localized dust plumes from the general haze in images acquired near midday, which we determine to be dust devils. Processing of 440 nm images highlights dust devils as distinct occultation features against the horizon. The dust devils are interpreted to be 14-79 m wide, 46-350 m tall, travel at 0.5-4.6 m/s, with dust loading of 7E-5 kg m-3, relative to the general haze of 9E-8 kg m-3, and total particulate transport of 2.2 - 700 kg. The vortices match predictions from terrestrial analog studies. Copyright 1999 by the American Geophysical Union.

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

1999-01-01

277

The LISA Pathfinder interferometryhardware 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.; Garca Marn, 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.; Garca Marirrodriga, C.; Gesa, L.; Gibert, F.; Giardini, D.; Grimani, C.; Grynagier, A.; Guillaume, B.; Guzmn, 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

278

Structural analyses of the JPL Mars Pathfinder impact  

NASA Astrophysics Data System (ADS)

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

Gwinn, Kenneth W.

279

Structural analyses of the JPL Mars Pathfinder impact  

SciTech Connect

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

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

1994-12-31

280

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

281

Catchment to Reef: Water Quality Issues in the  

E-print Network

Catchment to Reef: Water Quality Issues in the Great Barrier Reef Region. 9-11 March 2004, Townsville. Conference abstracts. Edited by: David Haynes1,3 and Britta Schaffelke2, 3 1 Great Barrier Reef, Australian Institute of Marine Science, Great Barrier Reef Marine Park Authority, Great Barrier Reef Research

Marsh, Helene

282

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...

283

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.

284

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. ? 2009 Elsevier Ltd. All rights reserved. 1. Introduction Coral reefs

Meyers, Steven D.

285

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

286

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

287

Building a comprehensive suite of technologies on the World Wide Web for the Pathfinder project  

E-print Network

from one party to another. This paper describes the specific requirements for information dissemination and educational programs for the Pathfinder project and outlines the design, building, and population of the internet site....

Graham, Scott Allen

2012-06-07

288

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

Lpez, L Necochea

2014-01-01

289

Threshold-of-Motion Wind Friction Speeds at the Mars Pathfinder Landing Site  

NASA Astrophysics Data System (ADS)

Threshold-of-motion wind friction speeds are calculated for the Pathfinder site, using IMP windsock results and shear-stress partitioning. Stronger winds than previous estimates must have occurred in the past to explain observed aeolian features.

Sullivan, R. J.

2002-03-01

290

Intercomparison Between in situ and AVHRR Polar Pathfinder-Derived Surface Albedo over Greenland.  

National Technical Information Service (NTIS)

The Advanced Very High Resolution (AVHRR) Polar Pathfinder Data (APP) provides the first long time series of consistent, calibrated surface albedo and surface temperature data for the polar regions. Validations of these products have consisted of individu...

J. C. Stroeve, J. E. Box, C. Fowler, T. Haran, J. Key

2001-01-01

291

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

292

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

293

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

294

Biological models for Mesozoic reef evolution  

SciTech Connect

Throughout the Mesozoic, shallow-water carbonate ramps and platforms of the circumequatorial Tethyan Ocean were characterized by extensive development of reef ecosystems, especially during times of eustatic highstand, expansion of the Tropics, and warm equable global climates. The greatest reef development was north of the paleoequator in the Caribbean and Indo-Mediterranean provinces. These reefs and associated debris facies comprise major petroleum reservoirs, in some cases with remarkable porosity and permeability normally attributed to a combination of sedimentologic, tectonic, and diagenetic factors. The biological evolution of Mesozoic reefs also has had an important, and in some cases dominant, role in determining reservoir quality. Three major biological factors are critical to mesozoic reef-associated reservoir development: (1) the replacement/competitive displacement of coral-algal dominated, highly integrated reef ecosystems by loosely packed rudistid bivalve-dominated reef ecosystems in the Barremian-Albian; (2) the evolution of dominantly aragonitic, highly porous shells among framework-building rudistids in the middle and Late Cretaceous; and (3) competitive strategies among rudistids that effectively prevented widespread biological binding of Cretaceous reefs, leading to the production of large marginal fans that comprise major carbonate reservoirs. Detailed studies of these evolutionary trends in reef/framework development and of the distribution of different groups of bioconstructors on reefs lead to predictive modeling for primary and secondary porosity development in mesozoic carbonate reservoirs. The competitive displacement of coral-algal communities by rudistids on Cretaceous reefs was so effective that, even after Maastrichtian mass extinction of rudistids and other important groups comprising Mesozoic reef/carbonate platform ecosystems, coral-algal reef-building communities did not evolve again until the late Eocene.

Kauffman, E.G. (Univ. of Colorado, Boulder (USA))

1990-11-01

295

The end-to-end testbed of the optical metrology system on-board LISA Pathfinder  

Microsoft Academic Search

LISA Pathfinder is a technology demonstration mission for the Laser Interferometer Space Antenna (LISA). The main experiment on-board LISA Pathfinder is the so-called LISA Technology Package (LTP) which has the aim to measure the differential acceleration between two free-falling test masses with an accuracy of 3 10-14 ms-2 Hz-1\\/2 between 1 mHz and 30 mHz. This measurement is performed

F. Steier; F. Guzmn Cervantes; A. F. Garca Marn; D. Gerardi; G. Heinzel; K. Danzmann

2009-01-01

296

78 FR 67128 - Coral Reef Conservation Program; Meeting  

Federal Register 2010, 2011, 2012, 2013

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

2013-11-08

297

Cooperative Multi-Agency Reef Fish Monitoring Protocol for the Florida Keys Coral Reef Ecosystem.  

National Technical Information Service (NTIS)

Reef fish populations are conspicuous and essential components of coral reef ecosystems in the south Florida region. Recent precipitous declines in these populations are believed to be due to severe habitat degradation as well as significant increases in ...

A. Acosta, J. A. Bohnsack, J. S. Ault, M. E. Brandt, N. Zurcher

2009-01-01

298

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

NASA Technical Reports Server (NTRS)

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

Smith, Elizabeth A.

1998-01-01

299

The semantic pathfinder: using an authoring metaphor for generic multimedia indexing.  

PubMed

This paper presents the semantic pathfinder architecture for generic indexing of multimedia archives. The semantic pathfinder extracts semantic concepts from video by exploring different paths through three consecutive analysis steps, which we derive from the observation that produced video is the result of an authoring-driven process. We exploit this authoring metaphor for machine-driven understanding. The pathfinder starts with the content analysis step. In this analysis step, we follow a data-driven approach of indexing semantics. The style analysis step is the second analysis step. Here, we tackle the indexing problem by viewing a video from the perspective of production. Finally, in the context analysis step, we view semantics in context. The virtue of the semantic pathfinder is its ability to learn the best path of analysis steps on a per-concept basis. To show the generality of this novel indexing approach, we develop detectors for a lexicon of 32 concepts and we evaluate the semantic pathfinder against the 2004 NIST TRECVID video retrieval benchmark, using a news archive of 64 hours. Top ranking performance in the semantic concept detection task indicates the merit of the semantic pathfinder for generic indexing of multimedia archives. PMID:16986547

Snoek, Cees G M; Worring, Marcel; Geusebroek, Jan-Mark; Koelma, Dennis C; Seinstra, Frank J; Smeulders, Arnold W M

2006-10-01

300

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

EPA Science Inventory

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

301

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

302

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...

303

Big Crater as Viewed by Pathfinder Lander - Anaglyph  

NASA Technical Reports Server (NTRS)

The 'Big Crater' is actually a relatively small Martian crater to the southeast of the Mars Pathfinder landing site. It is 1500 meters (4900 feet) in diameter, or about the same size as Meteor Crater in Arizona. Superimposed on the rim of Big Crater (the central part of the rim as seen here) is a smaller crater nicknamed 'Rimshot Crater.' The distance to this smaller crater, and the nearest portion of the rim of Big Crater, is 2200 meters (7200 feet). To the right of Big Crater, south from the spacecraft, almost lost in the atmospheric dust 'haze,' is the large streamlined mountain nicknamed 'Far Knob.' This mountain is over 450 meters (1480 feet) tall, and is over 30 kilometers (19 miles) from the spacecraft. Another, smaller and closer knob, nicknamed 'Southeast Knob' can be seen as a triangular peak to the left of the flanks of the Big Crater rim. This knob is 21 kilometers (13 miles) southeast from the spacecraft.

The larger features visible in this scene - Big Crater, Far Knob, and Southeast Knob - were discovered on the first panoramas taken by the IMP camera on the 4th of July, 1997, and subsequently identified in Viking Orbiter images taken over 20 years ago. The scene includes rocky ridges and swales or 'hummocks' of flood debris that range from a few tens of meters away from the lander to the distance of South Twin Peak. The largest rock in the nearfield, just left of center in the foreground, nicknamed 'Otter', is about 1.5 meters (4.9 feet) long and 10 meters (33 feet) from the spacecraft.

This view of Big Crater was produced by combining 6 individual 'Superpan' scenes from the left and right eyes of the IMP camera. Each frame consists of 8 individual frames (left eye) and 7 frames (right eye) taken with different color filters that were enlarged by 500% and then co-added using Adobe Photoshop to produce, in effect, a super-resolution panchromatic frame that is sharper than an individual frame would be.

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

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

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

1997-01-01

304

General Coral Reef Facts Healthy coral reefs are among the most biologically diverse and economically valuable  

E-print Network

it is extremely difficult to clean the oil. Effects of oil and dispersants on coral reefs Laboratory, field on current estimates, shallow water coral reefs occupy approximately 284,300 square kilometers (110,000 square miles) of the sea floor. If all of the world's shallow water coral reefs were placed side

305

Nitrogen excretion by some demersal macrozooplankton in Heron and One Tree Reefs, Great Barrier Reef, Australia  

Microsoft Academic Search

Nitrogen excretion rates of demersal macrozooplankton were measured together with nitrogen concentrations in the water column and sediments in lagoons of Heron Reef and One Tree Reef, Great Barrier Reef, Australia, during August and November 1991. Excretion rates increased with body weight, and weight-specific excretion rates of the demersal macrozooplankton were comparable to those of pelagic zooplankton and meiofauna in

J. W. Bishop; J. G. Greenwood

1994-01-01

306

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

307

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.

308

Succession and community structure of reef flat algae at Heron Island, Great Barrier Reef, Australia  

Microsoft Academic Search

There is little published information on the distribution, abundance, seasonality and ecological roles of benthic algae on the Great Barrier Reef, although they are of fundamental importance in the ecology of coral reef communities. This study sought to provide information on algal community dynamics in two contrasting reef-flat zones: the live coral and algal turf-dominated outer flat, and the fleshy

Claudia Frances Catterall

2002-01-01

309

Philippine Coral Reefs Under Threat: Lessons Learned After 25 Years of Community-Based Reef Conservation  

Microsoft Academic Search

The Philippine archipelago consists of more than 7000 islands. Most of these islands have extensive coral reefs or coral communities. For centuries, reefs and their associated resources have provided the livelihood for a large portion of the coastal population. However, reefs as sources of income are threatened by over-exploitation and by the use of destructive fishing methods. The scientific community,

Alan T White; Helge P Vogt

2000-01-01

310

Microbial photosynthesis in coral reef sediments (Heron Reef, Australia)  

NASA Astrophysics Data System (ADS)

We investigated microphytobenthic photosynthesis at four stations in the coral reef sediments at Heron Reef, Australia. The microphytobenthos was dominated by diatoms, dinoflagellates and cyanobacteria, as indicated by biomarker pigment analysis. Conspicuous algae firmly attached to the sand grains (ca. 100 ?m in diameter, surrounded by a hard transparent wall) were rich in peridinin, a marker pigment for dinoflagellates, but also showed a high diversity based on cyanobacterial 16S rDNA gene sequence analysis. Specimens of these algae that were buried below the photic zone exhibited an unexpected stimulation of respiration by light, resulting in an increase of local oxygen concentrations upon darkening. Net photosynthesis of the sediments varied between 1.9 and 8.5 mmol O 2 m -2 h -1 and was strongly correlated with Chl a content, which lay between 31 and 84 mg m -2. An estimate based on our spatially limited dataset indicates that the microphytobenthic production for the entire reef is in the order of magnitude of the production estimated for corals. Photosynthesis stimulated calcification at all investigated sites (0.2-1.0 mmol Ca 2+ m -2 h -1). The sediments of at least three stations were net calcifying. Sedimentary N 2-fixation rates (measured by acetylene reduction assays at two sites) ranged between 0.9 to 3.9 mmol N 2 m -2 h -1 and were highest in the light, indicating the importance of heterocystous cyanobacteria. In coral fingers no N 2-fixation was measurable, which stresses the importance of the sediment compartment for reef nitrogen cycling.

Werner, Ursula; Blazejak, Anna; Bird, Paul; Eickert, Gabriele; Schoon, Raphaela; Abed, Raeid M. M.; Bissett, Andrew; de Beer, Dirk

2008-03-01

311

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

312

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

313

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 500million people. Despite their importance, coral reefs\\u000a are declining at a rapid rate (12% per year) as a result of a range of local (e.g., overexploitation of fisheries, declining\\u000a water

Ove Hoegh-Guldberg

2011-01-01

314

Faunal relationships among the near-reef zooplankton at three locations on heron reef, great barrier reef, and seasonal changes in this fauna  

Microsoft Academic Search

Samples of zooplankton were collected using a light trap at 5 sites in 3 locations on Heron Reef: (a) near the surface of open water 300 m south of the reef crest; (b) near the surface and at the substratum on the upper reef slope; (c) near the surface and at the substratum on a patch reef in the Heron

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

1978-01-01

315

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

316

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

317

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

318

Coral Reef Protection: A Watershed Approach  

NSDL National Science Digital Library

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

Water., United S.

1998-01-01

319

Studies on the Great Barrier Reef  

SciTech Connect

Proposals to drill for oil on Australia's Great Barrier Reef have led to the appointment of a royal commission to study the environmental impact of such activities. The Australian Institute of Marine Science has developed a 5-part research plant which covers the Australian mangrove environment; nearshore habitat; processes and interactions, energy flows, resource cycling and their consequences within the reef ecosystems; patterns, abundances and relationships within the reef; and the continental shelf of the Great Barrier Reef region. Research in each of these areas is described.

Walton, S.

1985-01-01

320

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

321

Long-term monitoring of reef corals at the Flower Garden Banks (northwest Gulf of Mexico): Reef coral population changes and historical incorporation of barium in Montastrea annularis  

SciTech Connect

Reef coral populations were monitored from 1988 to 1991 at the Flower Garden Banks located in the northwestern Gulf of Mexico. The status of reef coral populations, and natural or man-made factors potentially affecting their well-being were determined. Man-made chronic disturbances are degrading coral reef resources on a global scale. Yet, the Flower Garden coral reefs seem to have been sheltered from the effects of regional stresses generated by population growth and increased industrial activity. Since 1974, reef coral population levels have remained unchanged in the Montastrea-Diploria Zones at the Flower Garden Banks. Live coral cover ranges between 46 and 46.5%. Montastrea annularis and Diploria strigosa comprise 80% of the coral cover on either bank. The remainder of the cover is mostly shared by eight other taxa. Coral taxa appear to be more homogeneously distributed on the West Bank. The relatively greater number of Agaricia spp., Madracis decastis, and P. astreoides colonies on the East Bank may be the source of a decreased evenness. The health of reef corals was assessed using repetitive and non-repetitive photographic methods, and accretionary growth measurements of M. annularis. Reef corals have undergone small scale changes at the Flower Gardens probably reflecting natural disturbance, predation, disease, and inter-specific competition. White mat disease (ridge disease) is shown to generate more tissue loss than any of the three bleaching events that took place at the Flower Gardens (1989, 1990, and 1991). Advance to retreat linear ratios of encrusting growth revealed a net tissue gain on the East Bank and a net tissue loss on the West Bank. Growth rates of M. annularis were highly variable. The annual barium content from 1910 in 1989 in a M. annularis colony from the West Flower Garden did not reveal trends associated with the extensive oil and gas exploration in the northern Gulf of Mexico.

Deslarzes, K.J.P.

1992-01-01

322

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

323

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

324

The case for testing MOND using LISA Pathfinder  

E-print Network

We quantify the potential for testing MOdified Newtonian Dynamics (MOND) with LISA Pathfinder (LPF), should a saddle point flyby be incorporated into the mission. We forecast the expected signal to noise ratio (SNR) for a variety of instrument noise models and trajectories past the saddle. For standard theoretical parameters the SNR reaches middle to high double figures even with modest assumptions about instrument performance and saddle approach. Obvious concerns, like systematics arising from LPF self-gravity, or the Newtonian background, are examined and shown not to be a problem. We also investigate the impact of a negative observational result upon the free-function determining the theory. We demonstrate that, if Newton's gravitational constant is constrained not be re-normalized by more than a few percent, only contrived MONDian free-functions would survive a negative result. There are exceptions, e.g. free-functions not asymptoting to 1 in the Newtonian limit, but rather diverging or asymptoting to zero (depending on their mother relativistic MONDian theory). Finally, we scan the structure of all proposed relativistic MONDian theories, and classify them with regards to their non-relativistic limit, finding three broad cases (with a few sub-cases depending on the form of the free function). It is appears that only the Einstein-Aether formulation, and the sub-cases where the free-function does not asymptote to 1 in other theories, would survive a negative result without resorting to "designer" free-functions.

Joao Magueijo; Ali Mozaffari

2011-07-06

325

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 description of ASKAP, this document contains 7 chapters describing specific science programmes for ASKAP. The combination of location, technological innovation and scientific program will ensure that ASKAP will be a world-leading radio astronomy facility, closely aligned with the scientific and technical direction of the SKA. A brief summary chapter emphasizes the point, and considers discovery space.

S. Johnston; R. Taylor; M. Bailes; N. Bartel; C. Baugh; M. Bietenholz; C. Blake; R. Braun; J. Brown; S. Chatterjee; J. Darling; A. Deller; R. Dodson; P. Edwards; R. Ekers; S. Ellingsen; I. Feain; B. Gaensler; M. Haverkorn; G. Hobbs; A. Hopkins; C. Jackson; C. James; G. Joncas; V. Kaspi; V. Kilborn; B. Koribalski; R. Kothes; T. Landecker; A. Lenc; J. Lovell; J. -P. Macquart; R. Manchester; D. Matthews; N. McClure-Griffiths; R. Norris; U. -L. Pen; C. Phillips; C. Power; R. Protheroe; E. Sadler; B. Schmidt; I. Stairs; L. Staveley-Smith; J. Stil; S. Tingay; A. Tzioumis; M. Walker; J. Wall; M. Wolleben

2008-10-29

326

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.

327

Slope Morphology of Twin Peaks, Mars Pathfinder Landing Site  

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

328

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

329

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

330

From ridge to reeflinking erosion and changing watersheds to impacts on the coral reef ecosystems of Hawaii 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 Hawaii 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

331

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

332

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

333

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

334

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

335

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

336

Preliminary observations on coral reef plankton  

Microsoft Academic Search

ABSTBRCT Plankton collections near coral reefs were made by hand-towing nets while swimming and by using a suction device for sampling caves. Plankton in sheltered areas was con- sidcrably different from that in nonsheltered areas; some plankton forms maintained position near coral reefs, indicating that the terms planktonic and epibenthic may represent extremes of a behavior continuum. Copepods were observed

ALAN R. EMERY

1968-01-01

337

Silurian pinnacle reefs of the Canadian Arctic  

SciTech Connect

Pinnacle reefs are commonly an attractive target for oil exploration because they are usually porous carbonate bodies entombed in impervious, deep-water shales that provide both the source and the seal for hydrocarbons. Silurian pinnacle reefs, the first described in the Canadian Arctic Archipelago, are exposed on Ellesmere and Devon Islands. Two main reef trends occur, one of early middle Llandovery to middle Ludlow age and a second of middle Ludlow to Late Silurian or Early Devonian age. Reefs of both phases contain lime mudstone cores: some are stromatactoid-rich and others consist predominantly of microbialite-rich lime mudstone or microbial boundstone. Facies sequences of both reef phases show evidence of upward-shallowing overall, but, in the older reefs, isochronous capping facies are dominated either by coral-mirian or by stromatoporoid boundstone and floatstone. This difference perhaps reflects variation in wave stress and apparent ability of a few corals,thickly encrusted by or associated with microbial boundstone and skeletal algae, to withstand greater wave energy than a stromatoporoid-coral-rich reef community. These reefs constitute one of the bright prospects of hydrocarbon exploration in rocks of the Franklinian succession. 43 refs., 9 figs.

De Freitas, T.A.; Dixon, O.A. (Univ. of Ottawa, Ontario (Canada)); Mayr, U. (Institute of Sedimentary and Petroleum Geology, Alberta (Canada))

1993-04-01

338

Reproductive ecology of Caribbean reef corals  

Microsoft Academic Search

The last decade has seen a resurgence of interest in the processes of sexual reproduction by scleractinian reef corals. Earlier investigations had focused fortuitously on brooding (planulating) species, which resulted in the general misconception that brooding was the main form of larval development of reef corals. More recent work on Indo-Pacific species has shown broadcast spawning and short annual reproductive

Alina M. Szmant

1986-01-01

339

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

340

Disease of coral and coral reef fishes  

USGS Publications Warehouse

The Department of the Interior protects sensitive habitats amounting to about 3,600,000 acres of coral reefs and other submerged lands. These reefs are important ecosystems in 13 National Wildlife Refuges, 10 National Parks and in certain territorial waters such as the Wake Atoll.

Panek, Frank

2008-01-01

341

Reefs and Learning: Education Evaluation Techniques  

ERIC Educational Resources Information Center

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

Stepath, Carl M.

2006-01-01

342

Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve  

NSDL National Science Digital Library

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

2011-04-22

343

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

344

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

345

Coral Reef Conservation in Marine Protected Areas  

E-print Network

Coral Reef Conservation in Marine Protected Areas A Case Study of Parque Nacional del Este 22203, USA Telephone: (703) 841-4860 Coral Reef Conservation in Marine Protected Areas: A Case Study Bello y Georgina Bustamante Coral(inside)-R1.id 11/5/01, 4:55 PM1 #12;Derechos reservados © 2001

Greer, Lisa

346

Coral reefs: Conserving the evolutionary sources  

Microsoft Academic Search

The current worldwide degradation of coral reefs constitutes an international problem that calls for immediate attention. A multitude of conservation hotspots scattered over the circumtropical seas have been identified, but there has been no general agreement as to how to attack the problem. The major difficulty seems to be the lack of a priority system. Are some reefs more important

John C. Briggs

2005-01-01

347

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

348

Numerical Modeling on Waves over Fringing Reef  

NASA Astrophysics Data System (ADS)

A fringing reef is a common type of coral reef which is composed with two main components, the reef flat and reef slope. The reef flat is usually found in fairly shallow water with a mild slope. Because the reef flat is adjacent to land, it plays an important role on dissipating the wave energy. Reef slope, on the other hand, is often quite steep which reflects the wave energy directly and introducing wave breaking. In order to have profound understanding on the energy dissipating mechanism, we idealize the reef setup and explore the flow field numerically. The wave flume is 30.35m long and the water depth is 0.45m. A 1:5.71 slope is used to represent the reef slope. Considering the complex wave field with strong turbulent, we perform the numerical simulation by solving the Large-Eddy Simulation (LES) model with volume-of-fluid (VOF) interface tracking algorithm. The numerical results are compared with our laboratory measurements. To accurately describe the incident wave generated by a piston-type wave maker, we utilize the moving-solid algorithm (MSA) to describe the interaction between the flow field and the moving paddle. The nonlinearity of the incident wave is 0.21. Highly accurate results can be seen in terms of the surface-elevation and mean velocity field. The results show that the when the waves are passing the fringing reef, they are able to generate the wave-driven current with wave set-up and set-down. Plunging-type breaking waves can also be observed at the crest area of the fringing reefs. Three different reef heights, 0.025m 0.05m, and 0.075m, are simulated and discussed where the still water depth is 0.1m. The results show that adding additional 50% of the reef height will increase about 15% of the vortex intensity in the reef upstream face and reduce about 10% of the current velocity in the downstream area.

Hsuan, H. P.; Wu, T.; Huang, Z.; Yao, Y.

2012-12-01

349

Coral Reef Information System: Discover NOAA's Data  

NSDL National Science Digital Library

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

2008-06-09

350

Coral Reef Information System: Discover NOAA's Data  

NSDL National Science Digital Library

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

351

Food availability affects growth in a coral reef fish  

Microsoft Academic Search

Pomacentrus amboinensis is common on small patch reefs within One Tree Lagoon (Great Barrier Reef), where it preferentially settles onto deep reefs. A preliminary experiment, in which juveniles were transplanted to identical reef structures at two sites, within two depth strata, indicated that juvenile growth and survivorship were better in deeper water. The hypothesis that this difference was due to

G. P. Jones

1986-01-01

352

Automated Annotation of Coral Reef Survey Images Oscar Beijbom  

E-print Network

Automated Annotation of Coral Reef Survey Images Oscar Beijbom Peter J. Edmunds David I. Kline B in image libraries awaiting annotation. This work addresses one such domain: coral reef coverage estimation. In this setting, the goal, as de- fined by coral reef ecologists, is to determine the percent- age of the reef

Jaffe, Jules

353

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

354

Status of the Coral Reef Ecosystems of Guam  

E-print Network

Status of the Coral Reef Ecosystems of Guam By Val Porter, Trina Leberer, Mike Gawel, Jay Gutierrez Marine Laboratory Technical Report No. 113 October 2005 #12;Status of the Coral Reef Ecosystems of Guam of the Coral Reef Ecosystems of Guam ii #12;Status of the Coral Reef Ecosystems of Guam iii Guam

Mcilwain, Jenny

355

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

356

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

357

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 worlds 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

358

-Congressional Policy Brief -International Year of the Reef 2008  

E-print Network

of these ecosystems. How can Congress help coral reef conservation? · Support reauthorization of the Coral Reef, coordinate, and strengthen U.S. government actions to conserve both domestic and international coral reef of sustainable use and conservation of coral reefs for future generations. The ICRI is an informal mechanism

359

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 1035S 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

360

Is proximity to land-based sources of coral stressors an appropriate measure of risk to coral reefs? An example from the Florida Reef Tract.  

PubMed

Localized declines in coral condition are commonly linked to land-based sources of stressors that influence gradients of water quality, and the distance to sources of stressors is commonly used as a proxy for predicting the vulnerability and future status of reef resources. In this study, we evaluated explicitly whether proximity to shore and connections to coastal bays, two measures of potential land-based sources of disturbance, influence coral community and population structure, and the abundance, distribution, and condition of corals within patch reefs of the Florida Reef Tract. In the Florida Keys, long-term monitoring has documented significant differences in water quality along a cross-shelf gradient. Inshore habitats exhibit higher levels of nutrients (DIN and TP), TOC, turbidity, and light attenuation, and these levels decrease with increasing distance from shore and connections to tidal bays. In clear contrast to these patterns of water quality, corals on inshore patch reefs exhibited significantly higher coral cover, higher growth rates, and lower partial mortality rates than those documented in similar offshore habitats. Coral recruitment rates did not differ between inshore and offshore habitats. Corals on patch reefs closest to shore had well-spread population structures numerically dominated by intermediate to large colonies, while offshore populations showed narrower size-distributions that become increasingly positively skewed. Differences in size-structure of coral populations were attributed to faster growth and lower rates of partial mortality at inshore habitats. While the underlying causes for the favorable condition of inshore coral communities are not yet known, we hypothesize that the ability of corals to shift their trophic mode under adverse environmental conditions may be partly responsible for the observed patterns, as shown in other reef systems. This study, based on data collected from a uniform reef habitat type and coral species with diverse life-history and stress-response patterns from a heavily exploited reef system, showed that proximity to potential sources of stressors may not always prove an adequate proxy for assigning potential risks to reef health, and that hypothesized patterns of coral cover, population size-structure, growth, and mortality are not always directly related to water quality gradients. PMID:17303183

Lirman, Diego; Fong, Peggy

2007-06-01

361

The Lisa Technology Package (LTP) Diagnostics In Lisa Pathfinder  

NASA Astrophysics Data System (ADS)

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

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

2010-01-01

362

Insights Into Nitrogen Isotope Fractionation in Coral Reefs  

NASA Astrophysics Data System (ADS)

Environmental integrity in the Florida Reef tract and the Caribbean has been the center of concern for the past 15-20 years. Both the recreational and scientific communities alike have noticed an overall decline in coral reef health. This decline has manifested itself in the form of increased fleshy macroalgae growth and reduced coral cover, and in some cases, wide-scale coral mortality. Given the increasing dependence on a tourism-oriented economy in both South Florida and the Caribbean, much attention has been focused on maintaining reef longevity. A high nutrient load is believed to be the leading cause of degradation in the predominantly oligotrophic environment. Various studies have cited increased run off and input of anthropogenic wastes as the origin of these nutrients. It has also been suggested that the stable isotopes of nitrogen may provide a tracer with which to recognize the impact of anthropogenic nutrients within the coral reefs ecosystem. However, in utilizing both nitrogen and carbon stable isotopic methods on samples of particulate organic matter (POM) taken over the last three years, we find little evidence of the input of anthropogenic waste. ?15N values of POM fluctuate between +1 and +9 per mille, but usually remain in the +4 to +6 per mille range. Additionally, ?13C values are even more consistent, maintaining a balance between -19 to -21 per mille. These data are consistent with natural open-ocean values for ?15N and ?13C, indicating a lack of intense and prolonged exposure to anthropogenic wastes in the Florida Keys.

Lamb, K. A.; Swart, P. K.; Ellis, G. S.

2002-12-01

363

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

364

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

365

AVHRR-Based Polar Pathfinder Products: Evaluation, Enhancement and Transition to MODIS  

NASA Technical Reports Server (NTRS)

The Advanced Very High Resolution Radiometer (AVHRR)-Based Polar Pathfinder (APP) products include calibrated AVHRR channel data, surface temperatures, albedo, satellite scan and solar geometries, and cloud mask, all composited into twice-per-day images, and daily averaged fields of sea ice motion, for regions poleward of 50 latitude. Our general goals under this grant: (1) Quantify the APP accuracy and sources of error by comparing Pathfinder products with field measurements; (2) Determine the consistency of mean fields and trends in comparison with longer time series of available station data and forecast model output; (3) Investigate the consistency of the products between the different AVHRR instruments over the 1982-present period of the NOAA program; and (4) Compare and annual cycle of the APP products with MODIS to establish a baseline for extending Pathfinder-type products into the new ESE period.

Fowler, Charles; Masalanik, James; Stone, Robert; Stroeve, Julienne; Emery, William

2001-01-01

366

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

367

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

368

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.

Goodwin, Mel

369

The Reef Environmental Education Foundation  

NSDL National Science Digital Library

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

2003-02-17

370

Beach and reef-flat sediments along the south shore of Molokai, Hawaii  

USGS Publications Warehouse

As part of the U.S. Geological Survey's multi-disciplinary Coral Reef Project addressing the health and geological variability of coral reef systems, sediment components and their distribution along the fringing reef on the south shore of the Hawaiian island of Molokai are being examined. Particular interest is being paid to the types and origin of sediment found on the reef. The south shore of Molokai is sheltered by one of the largest fringing reefs in the US. At approximately 50 km in length, up to 1.5 km in width, and covered by 90% live coral in many locations, the reef seemingly should be able to provide ample sediment for large carbonate beaches. However, siliciclastic grains supplied by erosion of the basaltic uplands of Molokai are often the most conspicuous individual nearshore sediment type. Coralline algae and coral are the most common carbonate components of the beaches. On the nearshore reef-flat, chemically-altered carbonate grains, particularly coralline algae, are the most abundant component. Molluscs and Halimeda may be common in specific locations, but are usually minor components. Sediment calcium carbonate levels increase to the west from a minimum at Kamalo, and are high along the east shore of Molokai. However, these general island-scale trends may be overridden by local influences, such as protected stream mouths or high carbonate growth rates. Additionally, trends seen on the beach and nearshore environments may not reflect trends a few hundred meters offshore since shore normal trends are more pronounced than shore parallel ones.

Calhoun, R.S.; Field, M.E.

2000-01-01

371

The SKA and its pathfinders in the next decade: synergies with the TMT  

NASA Astrophysics Data System (ADS)

The next decade will be extremely exciting for centimeter- and meter-wave radio astronomy. Large new facilities such as ASKAP, LOFAR and MeerKAT, as well as major retrofits to existing facilities such as the JVLA and WSRT, are under construction or have begun operations. While revolutionary in and of themselves, these facilities are also important pathfinders to the SKA, whose construction will begin towards the end of this decade. This talk will review the key science that will be delivered by the SKA pathfinders as well as that anticipated with SKA Phase One (2018-2023) and Phase Two (>2023), with a focus on potential synergies with the TMT.

Spekkens, Kristine

2014-07-01

372

Miocene reef carbonates of Mariana Islands  

SciTech Connect

Miocene carbonates in the southern Mariana Islands are impressive for their lithologic diversity, thicknesses (over 250 m), and geographic extent (> 20% combined outcrop coverage over four major high islands: Guam, Rota, Tinian and Saipan). Sections are dominated either by lagoonal algal-foraminiferal wackestones and mudstones with locally abundant high-energy shelly-skeletal facies, or by rubbly to muddy, fore-reef-to-bank deposits of packstones and grainstones with highly diverse and variable biogenic clasts. Fresh to deeply weathered volcaniclastic material may comprise at least 80% of some high-energy fore-reef facies, whereas lagoonal and bank deposits usually contain less than 0.5% terrigenous material. Surprisingly, the Miocene in the Marianas lacks almost completely any reef-core facies. Several poorly developed coral-rich mounds on Saipan and localized laminated red algal buildups on Guam appear to constitute the extant reef-wall facies in the Miocene. The lack of buildups may be a matter of differential survival; it may result from headland erosion and benching associated with emergence of narrow reef tracts as has been postulated by others for south Guam. Alternatively, the authors are proposing that Miocene bathymetry and the volume of terrigenous influx militated against significant reef core formation. Radiometric age dating of these reef carbonates has proven unsuccessful because pervasive diagenesis has transformed the entire Miocene section into low-magnesium calcite with minor and occasional dolomite. Freshwater phreatic diagenesis accounts for the principal porosity variation and trace element distribution.

Siegrist, H.G. Jr.

1988-02-01

373

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 Nio-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

374

Local variation in herbivore feeding activity on an inshore reef of the Great Barrier Reef  

Microsoft Academic Search

Threats to coral reefs may be manifested through an increase in macroalgae. Across the globe, phase-shifts from coral to macroalgal\\u000a dominance have been reported from the Caribbean, Indian and Pacific Oceans. While the Great Barrier Reef (GBR) is in relatively\\u000a good condition, inshore reefs may exhibit over 50% macroalgal cover. However, our understanding of the processes preventing\\u000a the macroalgal expansion

C. Cvitanovic; D. R. Bellwood

2009-01-01

375

Coral Reef Remote Sensing Database and Monitoring of Coral Reefs by ASTER  

Microsoft Academic Search

Coral reefs in the world are under the crisis of degradation both by increasing human activities in coastal zone and by the global changes. All the factors of the global change scenario would bring serious impact on coral reefs. Increase in CO2 suppress calcification in coral reefs. The world-wide bleaching event in 1997-1998 was supposed to be at least partly

H. Kayanne; T. Matsunaga; H. Kanbara; M. Kato

2001-01-01

376

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

377

Spectral reflectance of coral reef bottom-types worldwide and implications for coral reef remote sensing  

Microsoft Academic Search

Coral reef benthic communities are mosaics of individual bottom-types that are distinguished by their taxonomic composition and functional roles in the ecosystem. Knowledge of community structure is essential to understanding many reef processes. To develop techniques for identification and mapping of reef bottom-types using remote sensing, we measured 13,100 in situ optical reflectance spectra (400700 nm, 1-nm intervals) of 12

Eric J Hochberg; Marlin J Atkinson; Serge Andrfout

2003-01-01

378

Numerical modeling of atoll reef harbors  

SciTech Connect

The effect of the shape of a harbor cut through a reef on mitigating waves from the deep ocean was studied using a shallow water, nonlinear, long wave code called SWAN. A significant amount of the wave energy is dissipated over the reef regardless of the design of the harbor. The reef resulted in decreasing the wave height by a factor 3. The wave height at the shore can be further decreased by another factor of 2 by a ''V'' shaped or parabolic bottom design.

Mader, C.L.; Vitousek, M.; Lukas, S.

1986-01-01

379

High diversity of microplankton surrounds deep-water coral reef in the Norwegian Sea.  

PubMed

Coral reefs that exist in the depths of the oceans are surrounded by Eukarya, Archaea and bacterial communities that may play an important role in the nutrition and health of the reef. The first interdomain community structure of planktonic organisms in seawater from a deep-water coral reef is described. Community profiling and analysis of ribosomal RNA gene sequences from a coral reef system at 350m depth in the Norwegian Sea revealed a rich diversity of Eukarya and Bacteria and a moderate diversity of Archaea. Most sequences affiliated with marine microplankton from deep-sea to cold-surface regions, with many sequences being similar to those described in studies of mesopelagic and oxygen minimum zones. Dominant phylotypes belonged to the Alveolata (group I, II, dinoflagellates), Stramenopiles (silicoflagellates), Alphaproteobacteria (Pelagibacter ubique), Gammaproteobacteria (ARCTIC96BD-19), Bacteroidetes (Flavobacteria) and mesophilic Crenarchaeota (Nitrosopumilus maritimus). Several rare and novel members of the community fell into distinct phylogenetic groups. The inferred function of dominant community members suggested autotrophs that utilise light, ammonium or sulphide, and lifestyles based on host associations. The high diversity reflected a microplankton community structure, which is significantly different from that of microplankton collected at the same depth at a pelagic station away from reefs. PMID:22571287

Jensen, Sigmund; Bourne, David G; Hovland, Martin; Murrell, J Colin

2012-10-01

380

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

381

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

Federal Register 2010, 2011, 2012, 2013

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

2011-10-14

382

Terrestrial analogs to wind-related features at the Viking and Pathfinder landing sites on Mars  

Microsoft Academic Search

Features in the Mojave Desert and Iceland provide insight into the characteristics and origin of Martian wind-related landforms seen by the Viking and Pathfinder landers. The terrestrial sites were chosen because they exhibit diverse wind features that are generally well understood. These features have morphologies comparable to those on Mars and include origins by deposition and erosion, with erosional processes

Ronald Greeley; Nathan T. Bridges; Ruslan O. Kuzmin; Julie E. Laity

2002-01-01

383

Terrestrial analogs to wind-related features at the Viking and Pathfinder landing sites on Mars  

Microsoft Academic Search

(1) Features in the Mojave Desert and Iceland provide insight into the characteristics and origin of Martian wind-related landforms seen by the Viking and Pathfinder landers. The terrestrial sites were chosen because they exhibit diverse wind features that are generally well understood. These features have morphologies comparable to those on Mars and include origins by deposition and erosion, with erosional

Ronald Greeley; Nathan T. Bridges; Ruslan O. Kuzmin; Julie E. Laity

2000-01-01

384

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.

385

LINC-NIRVANA Pathfinder: testing the next generation of wave front sensors at LBT  

NASA Astrophysics Data System (ADS)

LINC-NIRVANA will employ four wave front sensors to realize multi-conjugate correction on both arms of a Fizeau interferometer for LBT. Of these, one of the two ground-layer wave front sensors, together with its infrared test camera, comprise a stand-alone test platform for LINC-NIRVANA. Pathfinder is a testbed for full LINC-NIRVANA intended to identify potential interface problems early in the game, thus reducing both technical, and schedule, risk. Pathfinder will combine light from multiple guide stars, with a pyramid sensor dedicated to each star, to achieve ground-layer AO correction via an adaptive secondary: the 672-actuator thin shell at the LBT. The ability to achieve sky coverage by optically coadding light from multiple stars has been previously demonstrated; and the ability to achieve correction with an adaptive secondary has also been previously demonstrated. Pathfinder will be the first system at LBT to combine both of these capabilities. Since reporting our progress at A04ELT2, we have advanced the project in three key areas: definition of specific goals for Pathfinder tests at LBT, more detail in the software design and planning, and calibration. We report on our progress and future plans in these three areas, and on the project overall.

Conrad, Albert R.; Arcidiacono, Carmelo; Baumeister, Harald; Bergomi, Maria; Bertram, Thomas; Berwein, Juergen; Biddick, Chris; Bizenberger, Peter; Brangier, Matthieu; Briegel, Florian; Brunelli, Alessandro; Brynnel, Joar; Busoni, Lorenzo; Cushing, Norm; De Bonis, Fulvio; De La Pena, Michele; Esposito, Simone; Farinato, Jacopo; Fini, Luca; Green, Richard F.; Herbst, Tom; Hofferbert, Ralph; Kittmann, Frank; Kuerster, Martin; Laun, Werner; Meschke, Daniel; Mohr, Lars; Pavlov, Aleksei; Pott, Jorg-Uwe; Puglisi, Alfio; Ragazzoni, Roberto; Rakich, Andrew; Rohloff, Ralf-Rainer; Trowitzsch, Jan; Viotto, Valentina; Zhang, Xianyu

2012-07-01

386

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

Microsoft Academic Search

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

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

1994-01-01

387

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

388

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

E-print Network

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

Gilbes, Fernando

389

Rationale for Isidis Planitia as a back-up landing site for the Mars Pathfinder mission  

NASA Technical Reports Server (NTRS)

The present engineering constraints imposed on the Mars Pathfinder mission leave only three broad regions available for site selection: Amazonis, Chryse, and Isidis Planitia. Because of the knowledge gained by the Viking 1 mission, Chryse Planitia would make an ideal primary landing site. Geological characteristics of Isidis Planitia are discussed with a view to making it a back-up landing site.

Craddock, Robert A.

1994-01-01

390

The Charge-Management System on LISA-Pathfinder - Status & Outlook for LISA  

Microsoft Academic Search

The electrostatic charging of the test masses in the Lisa Pathfinder inertial sensor has severe implications on the design, operation and noise behaviour of the sensor. The flight model (FM) charge management device (CMD) designed to keep the test masses at a low residual charge is currently being built at Imperial College, London. Detailed simulations and tests of the FM

M. Schulte; G. K. Rochester; D. N. A. Shaul; T. J. Sumner; C. Trenkel; P. J. Wass

2006-01-01

391

The Charge-Management System on LISA-Pathfinder Status & Outlook for LISA  

Microsoft Academic Search

The electrostatic charging of the test masses in the Lisa Pathfinder inertial sensor has severe implications on the design, operation and noise behaviour of the sensor. The flight model (FM) charge management device (CMD) designed to keep the test masses at a low residual charge is currently being built at Imperial College, London.Detailed simulations and tests of the FM uv-lamps,

M. Schulte; G. K. Rochester; D. N. A. Shaul; T. J. Sumner; C. Trenkel; P. J. Wass

2006-01-01

392

Do Integrated Children's Services Improve Children's Outcomes?: Evidence from England's Children's Trust Pathfinders  

ERIC Educational Resources Information Center

Thirty-five children's trust pathfinders, local cross-sector partnerships, were introduced across England in 2003 to promote greater integration in children's services. Using administrative performance data, this paper tracks yearly trends in child service outputs and child well-being outcomes from 1997 to 2004 in these local areas, including the

O'Brien, Margaret; Bachmann, Max O.; Jones, Natalia R.; Reading, Richard; Thoburn, June; Husbands, Chris; Shreeve, Ann; Watson, Jacqueline

2009-01-01

393

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.

394

Rock coatings and aeolian abrasion on Mars: Application to the Pathfinder landing site  

Microsoft Academic Search

Rock coatings can be used to constrain the rate of abrasion by wind on Mars. The susceptibility to abrasion for potential rock coatings on Mars (salt\\/salt-cemented coatings, rock varnish, and amorphous silica) were determined experimentally. Rock coatings generally abrade more easily than the host rock, although amorphous silica is an exception. If coatings exist on rocks at the Mars Pathfinder

Michael D. Kraft; Ronald Greeley

2000-01-01

395

Active Heat Rejection System on Mars Exploration Rover - Design Changes from Mars Pathfinder  

Microsoft Academic Search

The active Heat Rejection System designed for Mars Pathfinder was modified for the Mars Exploration Rover (Mars '03) mission and will be used to remove excess heat from the Rover electronics during the cruise part of the mission. The Integrated Pump Assembly design from MPF remained essentially intact; changes were primarily made to reduce weight. However, the cooling loop was

Gani B. Ganapathi; Gajanana C. Birur; Glenn T. Tsuyuki; Paul L. McGrath; Jack D. Patzold

2003-01-01

396

Active Heat Rejection System on Mars Exploration Rover Design Changes from Mars Pathfinder  

Microsoft Academic Search

The active Heat Rejection System designed for Mars Pathfinder was modified for the Mars Exploration Rover (Mars 03) mission and will be used to remove excess heat from the Rover electronics during the cruise part of the mission. The Integrated Pump Assembly design from MPF remained essentially intact; changes were primarily made to reduce weight. However, the cooling loop was

Gani B. Ganapathi; Gajanana C. Birur; Glenn T. Tsuyuki; Paul L. McGrath; Jack D. Patzold

2003-01-01

397

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

398

Opacity of the Martian atmosphere measured by the Imager for Mars Pathfinder  

Microsoft Academic Search

The Imager for Mars Pathfinder (IMP) has obtained 1733 images of the Sun during its 83-sol mission starting on July 4, 1997, which have been used to determine the atmospheric opacity at wavelengths of 450, 670, 883, and 989 nm. Solar images were obtained hourly between 0700 and 1700 hours, allowing detection of changes within a sol as well as

Peter H. Smith; Mark Lemmon

1999-01-01

399

EPA Field Manual for Coral Reef Assessments  

EPA Science Inventory

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

400

In Brief. ... A Tire Reef, "Ghost" Sea  

E-print Network

,,",o prohlbiteu.... ....A "tire baler." making artificial reef from old auto tires along Te\\as' coa,t thl' ,ummel niver~it) . . .. .Cold winter weather, combined with extremely low water level . caused a widespread

401

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...

402

Oysters and Oyster Reef Communities in Florida.  

ERIC Educational Resources Information Center

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

Knight, Jean; Bly, Joe

1989-01-01

403

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

404

Extinction vulnerability of coral reef fishes  

PubMed Central

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

2011-01-01

405

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

406

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

407

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

408

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

409

Predation in Ancient Reef-Builders  

Microsoft Academic Search

\\u000a Avoidance of predation is of critical importance to any organism, but reef-building organisms might be considered particularly\\u000a vulnerable due to their immobile, epifaunal life habit. The need for photosymbiotic metazoans to expose large areas of soft\\u000a tissue to light further increases the risk of predation, as well as fouling. It has been well established that modern coral\\u000a reefs grow in

Rachel Wood

410

Explore coral reefs around the world  

NSDL National Science Digital Library

This Earth science resource uses a world map to show students the locations of five coral reefs. Students are instructed to toggle between maps coded according to ocean depth or water temperature to determine the conditions required for coral growth. Each reef is indicated by a red dot that students click on to view a photograph and to read additional information. Copyright 2005 Eisenhower National Clearinghouse

Education, Terc. C.; Littell, Mcdougal

2003-01-01

411

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

412

Miocene reef carbonates of Mariana Islands  

SciTech Connect

Miocene carbonates in the southern Mariana Islands are impressive for their lithologic diversity, thicknesses (over 250 m), and geographic extend (>20% combined outcrop coverage over four major high islands: Guam, Rota, Tinian and Saipan). Sections are dominated either by lagoonal algal-foraminiferal wackestones and mudstones with locally abundant high-energy shelly-skeletal facies, or by rubbly to muddy, fore-reef-to-bank deposits of packstones and grainstones with highly diverse and variable biogenic clasts. Fresh to deeply weathered volcaniclastic material may comprise at least 80% of some high-energy fore-reef facies, whereas lagoonal and bank deposits usually contain less than 0.5% terrigenous material. Surprisingly, the Miocene in the Marianas lacks almost completely any reef-core facies. Several poorly developed coral-rich mounds on Saipan and localized laminated red algal buildups on Guam appear to constitute the extant reef-wall facies in the Miocene. The lack of buildups may be a matter of differential survival; it may result from headland erosion and benching associated with emergency of narrow reef tracts as has been postulated by others for south Guam. Radiometric age dating of these reef carbonates has proven unsuccessful because pervasive diagenesis has transformed the entire Miocene section into low-magnesium calcite with minor and occasional dolomite. Freshwater phreatic diagenesis accounts for the principal porosity variation and trace element distribution.

Siegrist, H.G. Jr.

1988-01-01

413

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

414

Space Technology 5: Pathfinder for Future Micro-Sat Constellations  

NASA Technical Reports Server (NTRS)

The Space Technology 5 (ST-5) Project, currently in the implementation phase, is part of the National Aeronautics and Space Administration (NASA) s New Millennium Program (NMP). ST-5 will consist of a constellation of three miniature satellites, each with mass less than 25 kg and size approximately 60 cm by 30 cm. ST-5 addresses technology challenges, as well as fabrication, assembly, test and operations strategies for future micro-satellite missions. ST-5 will be deployed into a highly eccentric, geo-transfer orbit (GTO). This will expose the spacecraft to a high radiation environment as well as provide a low level magnetic background. A three-month flight demonstration phase is planned to validate the technologies and demonstrate concepts for future missions. Each ST-5 spacecraft incorporates NMP competitively-selected breakthrough technologies. These include Cold Gas Micro-Thrusters for propulsion and attitude control, miniature X-band transponder for space-ground communications, Variable Emittance Coatings for dynamic thermal control, and CULPRiT ultra low power logic chip used for Reed-Solomon encoding. The ST-5 spacecraft itself is a technology that can be infused into future missions. It is a fully functional micro-spacecraft built within tight volume and mass constraints. It is built to withstand a high radiation environment, large thermal variations, and high launch loads. The spacecraft power system is low-power and low-voltage, and is designed to turn on after separation &om the launch vehicle. Some of the innovations that are included in the ST-5 design are a custom spacecraft deployment structure, magnetometer deployment boom, nutation damper, X-band antenna, miniature spinning sun sensor, solar array with triple junction solar cells, integral card cage assembly containing single card Command and Data Handling and Power System Electronics, miniature magnetometer, and lithium ion battery. ST-5 will demonstrate the ability of a micro satellite to perform research-quality science. Each ST-5 spacecraft will deploy a precision magnetometer to be used both for attitude determination and as a representative science instrument. The spacecraft has been developed with a low magnetic signature to avoid interference with the magnetometer. The spacecraft will be able to detect and respond autonomously to science events, i.e. significant changes in the magnetic field measurements. The three spacecraft will be a pathfinder for future constellation missions. They will be deployed to demonstrate an appropriate geometry for scientific measurements as a constellation. They will be operationally managed as a constellation, demonstrating automation and communication strategies that will be useful for future missions. The technologies and future mission concepts will be validated both on the ground and in space. Technologies will be validated on the ground by a combination of component level and system level testing of the flight hardware in a thermal vacuum environment. In flight, specific validation runs are planned for each of the technologies. Each validation run consists of one or more orbits with a specific validation objective. This paper will describe the ST-5 mission, and the applicability of the NMP technologies, spacecraft, and mission concepts to future missions. It will also discuss the validation approach for the ST-5 technologies and mission concepts.

Carlisle, Candace; Finnegan, Eric

2004-01-01

415

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

NASA Astrophysics Data System (ADS)

Remote sensing is increasingly being used as a tool to quantitatively assess the location, distribution and relative health of coral reefs and other shallow aquatic ecosystems. As the use of this technology continues to grow and the analysis products become more sophisticated, there is an increasing need for comprehensive ground truth data as a means to assess the algorithms being developed. The University of Puerto Rico at Mayaguez (UPRM), one of the core partners in the NSF sponsored Center for Subsurface Sensing and Imaging Systems (CenSSIS), is addressing this need through the development of a fully-characterized field test environment on Enrique Reef in southwestern Puerto Rico. This reef area contains a mixture of benthic habitats, including areas of seagrass, sand, algae and coral, and a range of water depths, from a shallow reef flat to a steeply sloping forereef. The objective behind the test environment is to collect multiple levels of image, field and laboratory data with which to validate physical models, inversion algorithms, feature extraction tools and classification methods for subsurface aquatic sensing. Data collected from Enrique Reef currently includes airborne, satellite and field-level hyperspectral and multispectral images, in situ spectral signatures, water bio-optical properties and information on habitat composition and benthic cover. We present a summary of the latest results from Enrique Reef, discuss our concept of an open testbed for the remote sensing community and solicit other users to utilize the data and participate in ongoing system development.

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

2006-09-01

416

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 of the > 4 mm class. Taphonomic biasing increased the abund- ance of crown-of-thorns starfish (COTS) skeletal of population explosions of the crown-of-thorns starfish (Acanthaster planci) on the Great Barrier Reefhas been

Greenstein, Benjamin J.

417

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

418

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 countrys 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

419

Reef structure drives parrotfish species composition on shelf edge reefs in La Parguera, Puerto Rico  

NASA Astrophysics Data System (ADS)

Shelf edge reefs that exist in coral reef ecosystems provide essential habitats for a large variety of fish and other marine organisms. Marine herbivores act as differential algal grazers that advocate coral reef colonization. In the Caribbean basin parrotfishes make up a large contingency of such herbivores and act as important ecological ichthyofauna. By investigating parrotfish relationship with habitat, this study aims to aid in future predictive mapping techniques that will outline parrotfish distributions via benthic quantification. Parrotfish communities were evaluated on the shelf edge reef off of La Parguera, Puerto Rico. Parrotfish abundances were found to positively correlate with high values of overall reef structure. High values of coral cover and of rugosity were strong indicators of most parrotfish species. The lone exception, Scarus taeniopterus, negatively correlated with these factors and positively correlated with algal cover. Indications exist that Scarus taeniopterus and Scarus iseri are sympatric species and can be found in abundance at opposite locations.

Tzadik, Orian E.; Appeldoorn, Richard S.

2013-02-01

420

Soundscapes from a Tropical Eastern Pacific reef and a Caribbean Sea reef  

NASA Astrophysics Data System (ADS)

Underwater soundscapes vary due to the abiotic and biological components of the habitat. We quantitatively characterized the acoustic environments of two coral reef habitats, one in the Tropical Eastern Pacific (Panama) and one in the Caribbean (Florida Keys), over 2-day recording durations in July 2011. We examined the frequency distribution, temporal variability, and biological patterns of sound production and found clear differences. The Pacific reef exhibited clear biological patterns and high temporal variability, such as the onset of snapping shrimp noise at night, as well as a 400-Hz daytime band likely produced by damselfish. In contrast, the Caribbean reef had high sound levels in the lowest frequencies, but lacked clear temporal patterns. We suggest that acoustic measures are an important element to include in reef monitoring programs, as the acoustic environment plays an important role in the ecology of reef organisms at multiple life-history stages.

Staaterman, E.; Rice, A. N.; Mann, D. A.; Paris, C. B.

2013-06-01

421

Reef odor: a wake up call for navigation in reef fish larvae.  

PubMed

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; Atema, Jelle; Irisson, Jean-Olivier; Kingsford, Michael; Gerlach, Gabriele; Guigand, Cedric M

2013-01-01

422

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

423

Variation in depth of whitetip reef sharks: does provisioning ecotourism change their behaviour?  

NASA Astrophysics Data System (ADS)

In the dive tourism industry, shark provisioning has become increasingly popular in many places around the world. It is therefore important to determine the impacts that provisioning may have on shark behaviour. In this study, eight adult whitetip reef sharks Triaenodon obesus were tagged with time-depth recorders at Osprey Reef in the Coral Sea, Australia. Tags collected time and depth data every 30 s. The absolute change in depth over 5-min blocks was considered as a proxy for vertical activity level. Daily variations in vertical activity levels were analysed to determine the effects of time of day on whitetip reef shark behaviour. This was done for days when dive boats were absent from the area, and for days when dive boats were present, conducting shark provisioning. Vertical activity levels varied between day and night, and with the presence of boats. In natural conditions (no boats present), sharks remained at more constant depths during the day, while at night animals continuously moved up and down the water column, showing that whitetip reef sharks are nocturnally active. When boats were present, however, there were also long periods of vertical activity during the day. If resting periods during the day are important for energy budgets, then shark provisioning may affect their health. So, if this behaviour alteration occurs frequently, e.g., daily, this has the potential to have significant negative effects on the animals' metabolic rates, net energy gain and overall health, reproduction and fitness.

Fitzpatrick, Richard; Abrantes, Ktya G.; Seymour, Jamie; Barnett, Adam

2011-09-01

424

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;