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Sample records for pleistocene patch reef

  1. Coral zonation and diagenesis of an emergent Pleistocene patch reef, Belize, Central America

    SciTech Connect

    Lighty, R.G.; Russell, K.L.

    1985-01-01

    Transect mapping and petrologic studies reveal a new depositional model and limited diagenesis of a well-exposed Pleistocene reef outcrop at Ambergris Cay, northern Belize. This emergent shelf-edge reef forms a rocky wave-washed headland at the northern terminus of the present-day 250 km long flourishing Belize Barrier Reef. Previously, the Belize reef outcrop was thought to extend southward in the subsurface beneath the modern barrier reef as a Pleistocene equivalent. The authors study indicate that this outcrop is a large, coral patch reef and not part of a barrier reef trend. Sixteen transects 12.5 m apart described in continuous cm increments from fore reef to back reef identified: extensive deposits of broken Acropora cervicornis; small thickets of A. palmata with small, oriented branches; and muddy skeletal sediments with few corals or reef rubble. Thin section and SEM studies show three phases of early submarine cementation: syntaxial and rosette aragonite; Mg-calcite rim cement and peloids; and colloidal Mg-calcite geopetal fill. Subaerial exposure in semi-arid northern Belize caused only minor skeletal dissolution, some precipitation of vadose whisker calcite, and no meteoric phreatic diagenesis. Facies geometry, coral assemblages, lack of rubble deposits, coralline algal encrustations and Millepora framework, and recognition of common but discrete submarine cements, all indicate that this Pleistocene reef was an isolated, coral-fringed sediment buildup similar to may large patch reefs existing today in moderate-energy shelf environments behind the modern barrier reef in central and southern Belize.

  2. Recent and relict topography of Boo Bee patch reef, Belize

    USGS Publications Warehouse

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

    1977-01-01

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

  3. ATRIS Seafloor Images – West Turtle Shoal Patch Reef, Rawa Patch Reef, Dustan Rocks Patch Reef, and Thor Patch Reef, Florida, 2011

    USGS Publications Warehouse

    Zawada, David G.; Ruzicka, Rob; Colella, Michael A.; Resnick, Jessica

    2016-01-01

    The U.S. Geological Survey St. Petersburg Coastal and Marine Science Center developed the Along-Track Reef Imaging System (ATRIS) in order to capture high-resolution, geo-located images of the seafloor. The images in this data release were collected September 29-30, 2011 at West Turtle Shoal, Rawa, Dustan Rocks, and Thor patch reefs near Marathon, Florida. The transects below show the path of image collection.For further information regarding data collection methods, refer to DOI: 10.1016/j.jembe.2015.02.017.

  4. Community dynamics of Pleistocene coral reefs during alternative climatic regimes.

    PubMed

    Tager, Danika; Webster, Jody M; Potts, Donald C; Renema, Willem; Braga, Juan C; Pandolfi, John M

    2010-01-01

    Reef ecosystems built during successive periods of Pleistocene sea level rise have shown remarkable persistence in coral community structure, but little is known of the ecological characteristics of reef communities during periods of low sea stands or sea level falls. We sampled the relative species abundance of coral, benthic foraminifera, and calcareous red algae communities from eight submerged coral reefs in the Huon Gulf, Papua New Guinea, which formed during successive sea level fall and lowstand periods over the past approximately kyr. We found that dissimilarity in coral species composition increased significantly with increasing time between reef-building events. However, neither coral diversity nor the taxonomic composition of benthic foraminifera and calcareous red algae assemblages varied significantly over time. The taxonomic composition of coral communities from lowstand reefs was significantly different from that of highstand reefs previously reported from the nearby Huon Peninsula. We interpret the community composition and temporal dynamics of lowstand reefs as a result of shifting energy regimes in the Huon Gulf, and differences between low and highstand reefs as a result of differences in the interaction between biotic and environmental factors between the Huon Gulf and Huon Peninsula. Regardless of the exact processes driving these trends, our study represents the first glimpse into the ecological dynamics of coral reefs during low sea level stands when climatic conditions for reef growth were much different and less optimal than during previously studied highstand periods.

  5. Early Pleistocene origin of reefs around Lanai, Hawaii

    USGS Publications Warehouse

    Webster, Jody M.; Clague, David A.; Faichney, Iain D.E.; Fullagar, Paul D.; Hein, James R.; Moore, James G.; Paull, Charles K.

    2010-01-01

    A sequence of submerged terraces (L1–L12) offshore Lanai was previously interpreted as reefal, and correlated with a similar series of reef terraces offshore Hawaii island, whose ages are known to be <500 ka. We present bathymetric, observational, lithologic and 51 87Sr/86Sr isotopic measurements for the submerged Lanai terraces ranging from −300 to −1000 m (L3–L12) that indicate that these terraces are drowned reef systems that grew in shallow coral reef to intermediate and deeper fore-reef slope settings since the early Pleistocene. Age estimates based on 87Sr/86Sr isotopic measurements on corals, coralline algae, echinoids, and bulk sediments, although lacking the precision (∼±0.23 Ma) to distinguish the age–depth relationship and drowning times of individual reefs, indicate that the L12–L3 reefs range in age from ∼1.3–0.5 Ma and are therefore about 0.5–0.8 Ma older than the corresponding reefs around the flanks of Hawaii. These new age data, despite their lack of precision and the influence of later-stage submarine diagenesis on some analyzed corals, clearly revise the previous correlations between the reefs off Lanai and Hawaii. Soon after the end of major shield building (∼1.3–1.2 Ma), the Lanai reefs initiated growth and went through a period of rapid subsidence and reef drowning associated with glacial/interglacial cycles similar to that experienced by the Hawaii reefs. However, their early Pleistocene initiation means they experienced a longer, more complex growth history than their Hawaii counterparts.

  6. Patch reef modeling: a comparison of Devonian and recent examples

    SciTech Connect

    Precht, W.F.

    1983-09-01

    In reef research, models have been developed to define variations in the lithic and biotic development of facies. Walker and Alberstadt, and Hoffman and Narkiewicz developed models for growth of ancient reef communities. Although these models form a solid foundation by which patch reefs can be classed and zoned, they are neither complete nor accurate for all reef types. A comparison was made of Lower Devonian patch reefs from the Appalachian basin of New York, New Jersey, and Pennsylvania, and Holocene examples from the Bahamas and Florida Keys to identify the structure, orientation, community variability, and succession of the reef biofacies. The complexion and genesis of the carbonate lithofacies were also studied. Results show similarities; these include the size, areal distribution, 3-D geometry, wave-resistance potential, lateral sequences of facies, sedimentary textures and structures, vertical zonation explained by growth from low-energy to high-energy regimes, biotic diversity, growth habit and form, and postmortem alteration. Thus, when used in conjunction with the traditional models, the recent can serve as the basis for a general model which include most patch reef types. However, these models should not be used as explicit analogs for all Phanerozoic reefs. Knowing and understanding the limitations of these comparative studies are essential to a fuller comprehension of the potential for variations which exist within and between the traditional models.

  7. The Morphology and Distribution of Submerged Reefs in the Maui Nui Complex, Hawaii: New Insights Into Their Evolution Since the Early Pleistocene

    NASA Astrophysics Data System (ADS)

    Faichney, I. D.; Webster, J. M.; Clague, D. A.; Kelley, C.; Appelgate, B.; Moore, J. G.

    2008-12-01

    Recent work on submerged drowned reefs in Hawaii has provided insight into reef development within the Late Pleistocene but reefs of the Early Pleistocene remain largely unexplored. The Maui-Nui Complex (MNC) provides a natural laboratory to study reef evolution throughout this time period as new data indicate the reefs grew from 1.1 - 0.5 Ma. We use new high resolution bathymetric data combined with existing regional data and field observations from ROV and submersible dives to make a detailed analysis of reef morphology and structure around the MNC. We focus specifically on the south-central region of the complex which provide the best reef exposure and find that the morphology of the reefs varies both regionally and temporally within this region. Barrier and pinnacle features dominate the steeper margins in the north of the study area while wide, shallow backstepping occurs to the south. Additionally, the central part of the study area shows karst morphology and patch and lagoonal features between the islands. We propose that this variation in the morphology and structure of the reefs has been controlled by variations in three main factors; the subsidence rates of the complex, the amplitude and period of eustatic sea-level cycles and finally the slope and continuity of the substrate. We argue that the interaction of these three factors explains the observed variations in reef morphology within the MNC and finally we present a new model of reef evolution over the last 1.5 Ma.

  8. Holocene Core Logs and Site Statistics for Modern Patch-Reef Cores: Biscayne National Park, Florida

    USGS Publications Warehouse

    Reich, Christopher D.; Hickey, T. Don; DeLong, Kristine L.; Poore, Richard Z.; Brock, John C.

    2009-01-01

    The bedrock in Biscayne National Park (BNP), a 1,730-square kilometer (km2) region off southeast Florida, consists of Pleistocene (1.8 million years ago (Ma) to 10,000 years ago (ka)) and Holocene (10 ka to present) carbonate rocks (Enos and Perkins, 1977; Halley and others, 1997; Multer and others, 2002). Most of the surficial limestone in BNP, including the islands of the Florida Keys, was formed at ~125 ka during the highstand of marine oxygen-isotope substage 5e, when sea level was approximately 6 meters (m) higher than today (Chappell and Shackleton, 1986; Multer and others, 2002; Lidz and others, 2003; Siddall and others, 2003; Balsillie and Donoghue, 2004). During the substage-5e regression, the entire Florida Platform became exposed. Subaerial exposure lasted for approximately 115,000 years (kyr), which resulted in erosion and enhancement of karst-like features (Lidz and others, 2006). As the Holocene transgression began to flood the Florida shelf ~7 to 6 ka, the bedrock depression under Biscayne Bay began to flood, and Holocene coral and reef debris laid the foundation for the present reef system (Enos and Perkins, 1977; Lighty and others, 1982; Toscano and Macintyre, 2003; Lidz and others, 2006). More than 3,000 patch reefs exist within the BNP boundary. Most contain hermatypic corals of various species such as those belonging to Montastrea, Diploria, Siderastrea, Porites, Acropora, and Agaricia. Patch reefs within BNP have two morphologies: pinnacle and flat top. Experimental Advanced Airborne Research Lidar (EAARL) data collected along the offshore BNP coral reef tract show that these two morphologies are clearly defined both in the high-resolution bathymetry maps produced by the Lidar data and by statistical analyses of the Lidar dataset (Brock and others, 2008). Brock and others (2008) also show that the pinnacle patch reefs are deeper than the more shallow, broad, and flat patch reefs. The control for these two patch-reef morphologies is unclear

  9. Explorationist's model of a patch-reef trap

    SciTech Connect

    Sams, R.H.

    1984-04-01

    A geologic model of a carbonate patch-reef complex is proposed. When applied to subsurface control where wells have been cored, the model is designed to actually position a well location with respect to a stratigraphic trap formed by the patch reef. The model is lithofacies governed and is based upon those facies relationships observed among several Gulf Cost patch-reef examples. The relationship between variations in effective porosity and permeability and the variations in lithofacies appears to be direct, judging from the examples studies. This direct relationship points to the formation of a permeability barrier stratigraphic trap where certain updip and lateral facies changes occur. Only primary porosity and permeability are considered by the model. The effects of secondary porosity, fracturing, dolomitization, and/or secondary cementation can be considered by a second model applied as an overprint to the first. Application of the model as an additional exploratory tool in carbonates where reservoir quality is a function of lithofacies distribution can lead to the drilling and discovery of numerous subtle stratigraphic traps.

  10. Resilience of predators to fishing pressure on coral patch reefs

    USGS Publications Warehouse

    Schroeder, R.E.; Parrish, J.D.

    2005-01-01

    Numbers and biomass of piscivorous fish and their predation on other fish may often be high in undisturbed coral reef communities. The effects of such predation have sometimes been studied by removal of piscivores (either experimentally or by fishermen). Such perturbations have usually involved removal of large, highly vulnerable, mobile piscivores that are often actively sought in fisheries. The effects of fishing on smaller, demersal, semi-resident piscivores have been little studied. We studied such effects on the fish communities of patch reefs at Midway atoll by experimentally removing major resident, demersal, piscivorous fishes. First, four control reefs and four experimental reefs were selected, their dimensions and habitats mapped, and their visible fish communities censused repeatedly over 1 year. Census of all control and experimental reefs was continued for the following 39 months, during which known piscivores were collected repeatedly by hand spearing. Records were kept of catch and effort to calculate CPUE as an index of predator density. Spearfishing on the experimental reefs removed 2504 piscivorous fish from 12 families and 43 taxa (mostly species). The species richness of the catch did not show an overall change over the duration of the experiment. Spearman rank correlation analysis showed some unexpected positive correlations for density in numbers and biomass of major fished piscivorous groups (especially lizardfish) over the experiment. Only two relatively minor fished piscivorous taxa declined in abundance over the experiment, while the overall abundance of piscivores increased. Visual censuses of fish on the experimental reefs also failed to show reduction of total piscivores over the full experimental period. No significant trend in the abundance of lizardfish censused over the full period was apparent on any of the control reefs. The high resilience of piscivores on these experimental reefs to relatively intense fishing pressure could

  11. Holocene coral patch reef ecology and sedimentary architecture, Northern Belize, Central America

    SciTech Connect

    Mazzullo, S.J.; Anderson-Underwood, K.E.; Burke, C.D.; Bischoff, W.D. )

    1992-12-01

    Coral patch reefs are major components of Holocene platform carbonate facies systems in tropical and subtropical areas. The biotic composition, growth and relationship to sea level history, and diagenetic attributes of a representative Holocene patch reef ([open quotes]Elmer Reef[close quotes]) in the Mexico Rocks complex in northern Belize are described and compared to those of Holocene patch reefs in southern Belize. Elmer Reef has accumulated in shallow (2.5 m) water over the last 420 yr, under static sea level conditions. Rate of vertical construction is 0.3-0.5 m/100 yr, comparable to that of patch reefs in southern Belize. A pronounced coral zonation exists across Elmer Reef, with Monastrea annularis dominating on its crest and Acropora cervicornis occurring on its windward and leeward flanks. The dominance of Montastrea on Elmer Reef is unlike that of patch reefs in southern Belize, in which this coral assumes only a subordinate role in reef growth relative to that of Acropora palmata. Elmer Reef locally is extensively biodegraded and marine, fibrous aragonite and some bladed high-magnesium calcite cements occur throughout the reef section, partially occluding corallites and interparticle pores in associated sands. Patch reefs in southern Belize have developed as catch-up and keep-up reefs in a transgressive setting. In contrast, the dominant mode of growth of Elmer Reef, and perhaps other patch reefs in Mexico Rocks, appears to be one of lateral rather than vertical accretion. This style of growth occurs in a static sea level setting where there is only limited accommodation space because of the shallowness of the water, and such reefs are referred to as [open quotes]expansion reefs[close quotes]. 39 refs., 8 figs., 2 tabs.

  12. Environmentally controlled succession in a late Pleistocene coral reef (Sinai, Egypt)

    NASA Astrophysics Data System (ADS)

    Mewis, H.; Kiessling, W.

    2013-03-01

    The concept of ecological succession has been frequently applied in the study of ancient reefs. Whereas Paleozoic and Mesozoic reefs are commonly thought to reveal an autogenic primary—climax zonation, patterns in Neogene and Quaternary reefs are much more diverse. Here, we describe a well-preserved late Pleistocene coral reef from Dahab on Sinai Peninsula (Egypt), which shows a distinct zonation that resembles an ecological succession. In contrast to classical examples of ecological successions, species composition, paleoenvironmental conditions, and coral biodiversity of the Dahab reef indicate an allogenic, sea-level controlled community change, from marginal marine to reef slope and back reef. A review of the literature confirms that autogenic, short-term successions are virtually absent in Quaternary reefs. We predict that long generation times of corals make it unlikely that classical autogenic successions develop in reefs at all, unless environmental conditions are unusually stable.

  13. Density of Diadema antillarum (Echinodermata: Echinoidea) on live coral patch reefs and dead Acropora cervicornis rubble patches near Loggerhead Key, Dry Tortugas National Park, Florida, USA

    EPA Science Inventory

    Density of adult Diadema antillarum was assessed on live coral patch reefs and dead Acropora cervicornis rubble patches next to Loggerhead Key, Dry Tortugas National Park, Florida, USA in June 2009. Mean density on live coral patch reefs (0.49 individuals m-2) was not statistical...

  14. Biophysical constraints on optimal patch lengths for settlement of a reef-building bivalve.

    PubMed

    Fuchs, Heidi L; Reidenbach, Matthew A

    2013-01-01

    Reef-building species form discrete patches atop soft sediments, and reef restoration often involves depositing solid material as a substrate for larval settlement and growth. There have been few theoretical efforts to optimize the physical characteristics of a restored reef patch to achieve high recruitment rates. The delivery of competent larvae to a reef patch is influenced by larval behavior and by physical habitat characteristics such as substrate roughness, patch length, current speed, and water depth. We used a spatial model, the "hitting-distance" model, to identify habitat characteristics that will jointly maximize both the settlement probability and the density of recruits on an oyster reef (Crassostrea virginica). Modeled larval behaviors were based on laboratory observations and included turbulence-induced diving, turbulence-induced passive sinking, and neutral buoyancy. Profiles of currents and turbulence were based on velocity profiles measured in coastal Virginia over four different substrates: natural oyster reefs, mud, and deposited oyster and whelk shell. Settlement probabilities were higher on larger patches, whereas average settler densities were higher on smaller patches. Larvae settled most successfully and had the smallest optimal patch length when diving over rough substrates in shallow water. Water depth was the greatest source of variability, followed by larval behavior, substrate roughness, and tidal current speed. This result suggests that the best way to maximize settlement on restored reefs is to construct patches of optimal length for the water depth, whereas substrate type is less important than expected. Although physical patch characteristics are easy to measure, uncertainty about larval behavior remains an obstacle for predicting settlement patterns. The mechanistic approach presented here could be combined with a spatially explicit metapopulation model to optimize the arrangement of reef patches in an estuary or region for

  15. Fletcher field: a Silurian patch/barrier-reef complex in southwestern Ontario

    SciTech Connect

    Meadows, J.R.; Churcher, P.L.; Lawson, D.E.; Dusseault, M.B.

    1986-08-01

    The importance of reef growth to Silurian oil and gas production in the Michigan basin is reflected in the large number of studies that have been conducted. Unfortunately, most of these studies have focused on pinnacle reefs, with patch and barrier reefs being virtually ignored, although they represent viable oil and gas exploration targets. Many patch reefs in Ontario also represent targets for enhanced oil recovery projects. Without detailed geologic studies, these projects cannot be readily implemented. A recent sedimentologic study defined the facies distribution of a patch- and barrier-reef complex and its associated producing zones (A-1 carbonate). The Fletcher field, located in southwestern Ontario, was chosen for study. Structures and facies relationships were defined using nine cored holes and geophysical well logs. In addition, detailed studies were made of the clay mineralogy and the controversial Guelph A-1 carbonate contact. Defined facies relationships indicate that the Fletcher patch/barrier reef differs in many respects to pinnacle reefs. The facies are simpler and fewer, consisting of a poorly zoned reef core overlain by a micritized reef-top, lagoonal, and supratidal sequence. The origin of the green shale at the Guelph A-1 contact is interpreted as resulting partly from subaerial exposure and partly from the concentration of insolubles by pressure solution. The clay mineralogy consists of a monomineralic assemblage of illite. The amount and distribution of this assemblage would not significantly affect enhanced oil recovery.

  16. Airborne lidar sensing of massive stony coral colonies on patch reefs in the northern Florida reef tract

    USGS Publications Warehouse

    Brock, J.C.; Wright, C.W.; Kuffner, I.B.; Hernandez, R.; Thompson, P.

    2006-01-01

    In this study we examined the ability of the NASA Experimental Advanced Airborne Research Lidar (EAARL) to discriminate cluster zones of massive stony coral colonies on northern Florida reef tract (NFRT) patch reefs based on their topographic complexity (rugosity). Spatially dense EAARL laser submarine topographic soundings acquired in August 2002 were used to create a 1-m resolution digital rugosity map for adjacent NFRT study areas characterized by patch reefs (Region A) and diverse substratums (Region B). In both regions, sites with lidar-sensed rugosities above 1.2 were imaged by an along-track underwater videography system that incorporated the acquisition of instantaneous GPS positions. Subsequent manual interpretation of videotape segments was performed to identify substratum types that caused elevated lidar-sensed rugosity. Our study determined that massive coral colony formation, modified by subsequent physical and biological processes that breakdown patch reef framework, was the primary source of topographic complexity sensed by the EAARL in the NFRT. Sites recognized by lidar scanning to be topographically complex preferentially occurred around the margins of patch reefs, constituted a minor fraction of the reef system, and usually reflected the presence of massive coral colonies in cluster zones, or their derivatives created by mortality, bioerosion, and physical breakdown.

  17. Stratigraphy and evolution of emerged Pleistocene reefs at the Red Sea coast of Sudan

    NASA Astrophysics Data System (ADS)

    Hamed, Basher; Bussert, Robert; Dominik, Wilhelm

    2016-02-01

    Emerged Pleistocene coral reefs constitute a prominent landform along the Red Sea coast of Sudan. They are well exposed with a thickness of up to 12 m and extend over a width of about 3 km parallel to the coastline. Four major reef units that represent different reef zones are distinguished. Unit 1 is located directly at the coastline and is assigned to the rock-reef rim, while unit 2 represents the reef-front zone. Unit 3 is attributed to the reef-flat zone and unit 4 to the back-reef zone. The stratigraphic position and age of the four units respectively the facies zones are based on field relationships and δ18O analysis. Results of δ18O analysis of coral, gastropod and bivalve samples were correlated to previous age dating of correlative reefs in Sudan and other parts of the Red Sea region. Estimation of reef ages was mainly based on δ18O values of the reef-front zone (unit 2) and the observed sedimentary succession of the reefs. δ18O values of two Porites coral samples from the reef-front zone strongly suggest equivalent ages of 120 and 122 ka that correspond to marine isotope stage MIS 5.5. Based on δ18O values and the field relationship to the reef-front zone, ages of reef-flat zone (unit 3) and back-reef zone (unit 4) could be assigned to MIS 9 and MIS 7 respectively. MIS 5.1 is suggested for the reef-rock rim (unit 1). The relationship of the reef zones to individual MIS might be explained by the predominance of a specific zone during a certain stage, while other facies were less well developed and/or later eroded by wave action. The reef unit most distal from the recent coastline formed during interglacial stage MIS 7, while former studies assign this unit to interglacial stage MIS 9. Unique flourishing, high diversity and excellent preservation of corals in the back-reef unit of MIS 7 reflect growth in troughs landward of the oldest reef-flat formed during previous interglacial stage MIS 9.

  18. Reef facies distribution patterns, Pleistocene (125 Ka) Falmouth Formation, Rio Bueno, Jamaica, W. I

    SciTech Connect

    Precht, W.F. ); Hoyt, W.H. )

    1991-03-01

    Detailed paleoecologic and sedimentologic studies of the well-exposed, Pleistocene (125 Ka) Falmouth Formation from Rio Bueno, Jamaica, where undertaken to define both temporal and spatial changes in reef architecture. Analyses of samples reveal an overall shallowing - upwards motif and a distinct lateral zonation of reefal facies similar to those observed in Recent fringing-reef and bank-barrier reef complexes from the eastern and western sides of Discovery Bay, Jamaica, respectively. The Falmouth Formation that crops out on the eastern shore of Rio Bueno Harbor is continually exposed (north-south) for approximately 0.5 km in length. The top of the reef exposure is approximately +4.5 m above MSL. This height correlates directly with sea level maxima for the Sangamon in Jamaica based upon a wavecut notch in the Hopegate Formation at the top of the Falmouth onlap surface. Interpretation of these deposits indicates that no lagoon or back-reef facies were present and that there was a gradation of energy regimes from high-to-low, north-to-south within this true fringing reef complex. Detailed sedimentologic analysis of thin-sections from all the above lithologies confirms the aforementioned paleoenvironmental interpretations. This study emphasizes the usefulness of modern counterparts in Pleistocene reef analysis and interpretation, and allows for an understanding of temporal (vertical) and spatial (horizontal) variations due to both physical disturbance and local sea level history that are preserved in these reefal deposits.

  19. Temporal comparison and predictors of fish species abundance and richness on undisturbed coral reef patches.

    PubMed

    Wagner, Elena L E S; Roche, Dominique G; Binning, Sandra A; Wismer, Sharon; Bshary, Redouan

    2015-01-01

    Large disturbances can cause rapid degradation of coral reef communities, but what baseline changes in species assemblages occur on undisturbed reefs through time? We surveyed live coral cover, reef fish abundance and fish species richness in 1997 and again in 2007 on 47 fringing patch reefs of varying size and depth at Mersa Bareika, Ras Mohammed National Park, Egypt. No major human or natural disturbance event occurred between these two survey periods in this remote protected area. In the absence of large disturbances, we found that live coral cover, reef fish abundance and fish species richness did not differ in 1997 compared to 2007. Fish abundance and species richness on patches was largely related to the presence of shelters (caves and/or holes), live coral cover and patch size (volume). The presence of the ectoparasite-eating cleaner wrasse, Labroides dimidiatus, was also positively related to fish species richness. Our results underscore the importance of physical reef characteristics, such as patch size and shelter availability, in addition to biotic characteristics, such as live coral cover and cleaner wrasse abundance, in supporting reef fish species richness and abundance through time in a relatively undisturbed and understudied region.

  20. Biological Communities and Geomorphology of Patch Reefs in Biscayne National Park, Florida, U.S.A.

    USGS Publications Warehouse

    Kuffner, Ilsa B.; Brock, John C.; Grober-Dunsmore, Rikki; Hickey, T. Don; Bonito, Victor; Bracone, Jeremy E.; Wright, C. Wayne

    2008-01-01

    Coral reef ecosystem management benefits from continual, quantitative assessment of the resources being managed, plus assessment of factors that affect distribution patterns of organisms in the ecosystem. In this study, we investigated the relationships among physical, benthic, and fish variables in effort to help explain the distribution patterns of ecologically and economically important species on twelve patch reefs within Biscayne National Park (BNP), Florida, U.S.A. We visited 196 randomly-located sampling stations across twelve shallow (< 10m) patch reefs, using SCUBA to conduct our surveys. We measured physical variables (e.g., substratum type), estimated the percent cover of benthic community members (e.g., coral, algae), and counted and estimated mean size for each fish species observed. We also used high-density bathymetric data collected remotely via airborne laser surveying (Experimental Advanced Airborne Research Lidar (EAARL)) to calculate rugosity (bumpiness) of the reef habitat. Here we present our findings visually by graphing our quantitative community and physical structure data simultaneously in a GIS map format. You will see that biological organisms arrange themselves on each patch reef in a non-random manner. For example, many species of fish prefer to locate themselves in areas of the reef where the rugosity index is high. Rugose parts of the reef provide them with good hiding places from predators. These maps (and the data used to create them) are permanent records of the status of reef resources found on these twelve patch reefs in BNP as of September, 2003. The survey data found in the shapefile located on this CD product includes benthic percent cover data for algae, coral, encrusting invertebrates, and substratum type, in addition to gorgonian abundance and volume, total fish abundance and species richness, and specific counts for Acanthurids (surgeonfish), Scarids (parrotfish), Lutjanids (snappers), Haemulids (grunts), Serranids

  1. Elevated reefs and related Pleistocene stratigraphy of the southern Exuma Islands, Bahamas

    SciTech Connect

    Dill, R.F. Caribbean Marine Research Center, San Diego, CA ); Halley, R.B.; Shinn, E.A.; Kindinger, J.L. ); Muhs, D.R. )

    1991-03-01

    At least seven elevated coral reefs are exposed on the lee side of an inner chain of low islands on the eastern margin of Great Bahama Bank in the Southern Exumas. Starting at Fowl Cay in the north, they extend at least to Pigeon Cay in the south, a distance of about 44 nautical mi (81 km). These reefs formed around preexisting Pleistocene core-islands and hardgrounds during a transgressive higher than present stand of sea level, prior to the Holocene. As sea level dropped, the reefs were karstedand capped by caliche crusts, a unique paleosol breccia containing land snails (Cerithidea. sp.) and a now lithified dune system with well-developed rhizomorphs. Shallow sea caves eroded into steep, clifflike notches are often located on ridges shoreward of the reef, with roof heights of up to 5 m above the top of the elevated reefs. The reefs form a 5- to 10-m wide terrace, approximately 1 m above present sea level. Shoreline exposures often exceed 300 m (1,000 ft). Most exposures have a base thicket of interwoven branches of Acropora cervicornus approximately 70-cm thick. The badly corroded branches are surrounded by a cemented matrix of ooid sands, marine cement, and coralline debris. The upper 30 cm is formed by a much more diverse reef community of broken shells and corals (Montastrea, Diploria Agaricia, Porites, and Acropora). Crustose coralline algae and colonial foraminifera (Homotrema) form a cementing crust around many corals. These reefs and their relationship to paleosols within subaerial dune deposits provide stratigraphic markers that play an important role in interpreting the development of Pleistocene deposits of the Great Bahama Bank.

  2. Pleistocene corals of the Florida keys: Architects of imposing reefs - Why?

    USGS Publications Warehouse

    Lidz, B.H.

    2006-01-01

    Five asymmetrical, discontinuous, stratigraphically successive Pleistocene reef tracts rim the windward platform margin off the Florida Keys. Built of large head corals, the reefs are imposing in relief (???30 m high by 1 km wide), as measured from seismic profiles. Well dated to marine oxygen isotope substages 5c, 5b, and 5a, corals at depth are inferred to date to the Stage 6/5 transition. The size of these reefs attests to late Pleistocene conditions that repeatedly induced vigorous and sustained coral growth. In contrast, the setting today, linked to Florida Bay and the Gulf of Mexico, is generally deemed marginal for reef accretion. Incursion onto the reef tract of waters that contain seasonally inconsistent temperature, salinity, turbidity, and nutrient content impedes coral growth. Fluctuating sea level and consequent settings controlled deposition. The primary dynamic was position of eustatic zeniths relative to regional topographic elevations. Sea level during the past 150 ka reached a maximum of ???10.6 m higher than at present ???125 ka, which gave rise to an inland coral reef (Key Largo Limestone) and ooid complex (Miami Limestone) during isotope substage 5e. These formations now form the Florida Keys and a bedrock ridge beneath The Quicksands (Gulf of Mexico). High-precision radiometric ages and depths of dated corals indicate subsequent apices remained ???15 to 9 m, respectively, below present sea level. Those peaks provided accommodation space sufficient for vertical reef growth yet exposed a broad landmass landward of the reefs for >100 ka. With time, space, lack of bay waters, and protection from the Gulf of Mexico, corals thrived in clear oceanic waters of the Gulf Stream, the only waters to reach them.

  3. Stratigraphy and chronology of late pleistocene reefs in the Southern Cook Islands, south Pacific

    NASA Astrophysics Data System (ADS)

    Woodroffe, Colin D.; Short, Stephen A.; Stoddart, David R.; Spencer, Tom; Harmon, Russell S.

    1991-03-01

    The Makatea Islands in the southern Cook Islands consist of a degraded volcanic core surrounded by emergent "makatea" limestones. While much of this reefal limestone is of Tertiary age, the seawardmost reefs are late Pleistocene. Last-interglacial reefs (oxygen isotope substage 5e) identified by U-series dating reach 12.2 m on Atiu (mean age of three samples 126,000 ± 5000 yr B.P.), 9.8 m on Mitiaro (mean age of five samples 119,000 ± 3000 yr B.P.), 10.0-12.7 m on Mauke (mean age of four samples 128,000 + 5000, -4,000 yr B.P.), and 14.5-20.0 m on Mangaia (mean age of four samples 115,000 ± 7000 yr B.P.). On Atiu, Mauke, and Mitiaro a lower reef unit has been identified, and is separated from the overlying substage 5e reef by a sharp discontinuity, often with a crust of coralline algae. U-series dating from Atiu and Mauke indicates that this is a stage 7 reef formed in the penultimate interglaciation. The Makatea Islands have emerged as a result of flexure of the lithosphere in response to loading by the Pleistocene volcanic island of Rarotonga. Isolated outcrops of makatea limestone on Rarotonga reach 3.5 m and are probably of substage 5e age. Elastic and viscoelastic models of lithospheric flexure predict that much of the compensatory movement should occur shortly after the emplacement of the load. However, the age and elevation of late Quaternary reefs on the southern Cook Islands, where a Pleistocene volcanic island has loaded relatively old ocean floor (>80 myr), indicate that differential uplift has been continuing over the last 250,000 yr.

  4. Biological community structure on patch reefs in Biscayne National Park, FL, USA

    USGS Publications Warehouse

    Kuffner, Ilsa B.; Grober-Dunsmore, Rikki; Brock, John C.; Hickey, T. Don

    2010-01-01

    Coral reef ecosystem management benefits from continual quantitative assessment of the resources being managed, plus assessment of factors that affect distribution patterns of organisms in the ecosystem. In this study, we investigate the relationships among physical, benthic, and fish variables in an effort to help explain the distribution patterns of organisms on patch reefs within Biscayne National Park, FL, USA. We visited a total of 196 randomly selected sampling stations on 12 shallow (<10 m) patch reefs and measured physical variables (e.g., substratum rugosity, substratum type) and benthic and fish community variables. We also incorporated data on substratum rugosity collected remotely via airborne laser surveying (Experimental Advanced Airborne Research Lidar—EAARL). Across all stations, only weak relationships were found between physical, benthic cover, and fish assemblage variables. Much of the variance was attributable to a “reef effect,” meaning that community structure and organism abundances were more variable at stations among reefs than within reefs. However, when the reef effect was accounted for and removed statistically, patterns were detected. Within reefs, juvenile scarids were most abundant at stations with high coverage of the fleshy macroalgae Dictyota spp., and the calcified alga Halimeda tuna was most abundant at stations with low EAARL rugosity. Explanations for the overwhelming importance of “reef” in explaining variance in our dataset could include the stochastic arrangement of organisms on patch reefs related to variable larval recruitment in space and time and/or strong historical effects due to patchy disturbances (e.g., hurricanes, fishing), as well as legacy effects of prior residents (“priority” effects).

  5. Holocene reef associated carbonate sediments and their Pleistocene counterparts, Miyako Islands, Ryukyus, southwest of Japan

    SciTech Connect

    Tsuji, Y.; Yamamura, T.; Kodato, T.; Sunouchi, H.

    1988-01-01

    Holocene carbonate sedimentary facies distribution, from sea level to shelf slope about 1,000 m in depth, and its relationship to bathymeltry, off Miyako Island, Ryukyus, southwest of Japan were clarified by surveys with sidescan sonar, sparker, uniboom, sea-bottom camera, and sediment sampler. Six facies were recognized using the acoustic data, sample analytical data, and sea-bottom photographs. These are as follows: (A) Reef facies: made mainly of autochthonous hermatypic corals and encrusting algae, 0-60 m deep. (B) Inter-reef muddy facies: consists of very fine sand-size carbonate fraction and line mud, 20-60 m deep surrounded area be reefal relief and islands. (C) Inter-reef and near-reef sandy facies: characterized by tests of shallow benthic foraminifera Calcarina and Marginopora, and Halimeda fragments, 0-90 m deep. (D) Rhodolith and large foraminiferal gravelly shelf facies: contains pebble to cobble-size rhodolith and/and foraminifera Cycloclypeus and Operculina, 60-200 m deep. (E) Bryozoan sandy shelf facies: rich in byrozoan fragments, 80-200 m deep. (F) Shelf slope pelagic foraminiferal facies: dominated by pelagic foraminifera and pteropod molluscan tests, deeper than 200 m. Counterparts of these facies in emerged Pleistocene limestone sequences have been recognized in outcrops and core samples. The results of the marine survey on Holocene deposits made it easy to interpret the Pleistocene depositional environments and sea level changes.

  6. Characterization of available light for seagrass and patch reef productivity in Sugarloaf Key, Lower Florida Keys

    USGS Publications Warehouse

    Toro-Farmer, Gerardo; Muller-Karger, Frank E.; Vega-Rodriguez, Maria; Melo, Nelson; Yates, Kimberly K.; Johns, Elizabeth; Cerdeira-Estrada, Sergio; Herwitz, Stan R.

    2016-01-01

    Light availability is an important factor driving primary productivity in benthic ecosystems, but in situ and remote sensing measurements of light quality are limited for coral reefs and seagrass beds. We evaluated the productivity responses of a patch reef and a seagrass site in the Lower Florida Keys to ambient light availability and spectral quality. In situ optical properties were characterized utilizing moored and water column bio-optical and hydrographic measurements. Net ecosystem productivity (NEP) was also estimated for these study sites using benthic productivity chambers. Our results show higher spectral light attenuation and absorption, and lower irradiance during low tide in the patch reef, tracking the influx of materials from shallower coastal areas. In contrast, the intrusion of clearer surface Atlantic Ocean water caused lower values of spectral attenuation and absorption, and higher irradiance in the patch reef during high tide. Storms during the studied period, with winds >10 m·s−1, caused higher spectral attenuation values. A spatial gradient of NEP was observed, from high productivity in the shallow seagrass area, to lower productivity in deeper patch reefs. The highest daytime NEP was observed in the seagrass, with values of almost 0.4 g·O2·m−2·h−1. Productivity at the patch reef area was lower in May than during October 2012 (mean = 0.137 and 0.177 g·O2·m−2·h−1, respectively). Higher photosynthetic active radiation (PAR) levels measured above water and lower light attenuation in the red region of the visible spectrum (~666 to ~699 nm) had a positive correlation with NEP. Our results indicate that changes in light availability and quality by suspended or resuspended particles limit benthic productivity in the Florida Keys.

  7. Ecological characteristics of coral patch reefs at Midway Atoll, Northwestern Hawaiian Islands

    USGS Publications Warehouse

    Schroeder, R.E.; Parrish, J.D.

    2006-01-01

    Ecological aspects of coral patch reefs were studied from 1981 to 1985 in Welles Harbor, Midway Atoll. Water temperatures varied from 17??C in February to 28??C in August. Sizes of reefs studied were described by mean area (59 m2), mean volume (52 m3), vertical relief (<1 m), and inter-reef isolation (100 m). Considerable temporal change in reef size occurred due to large winter swells shifting bottom sand. Six common species accounted for 70% of all individual fish visually censused over 4 years. Overall fish assemblage composition ranged from 11 to 46 fish/10 m2, from 3 to 14 species. Numerical abundance and species richness for all fish (pooled) strongly correlated with physical reef substrate characteristics of area, volume, and vertical relief during summer. Species diversity (H') was not correlated with the substrate variables, suggesting similarity in the structure of fish communities among different sizes of patch reefs. Daily surveillance for presence of large transient taxa suggested that visits by sharks, large jacks, monk seals, sea turtles, and dolphins were infrequent. Density estimates were made for all conspicuous invertebrate megafauna during initial and final assessments. Six common taxa provided 90% of these counts; nearly half were sea urchins. Percent cover also was recorded for coral and algal species on the patch reefs. Cover by live coral was low (about 7%) and dominated by a few species. Mean algal cover ranged from 32 to 77%. Such information on ecological characteristics of reefs may aid in understanding complex ecological processes and provides an earlier reference for current ecosystem studies.

  8. Environmental drivers of diurnal visits by transient predatory fishes to Caribbean patch reefs.

    PubMed

    Harborne, A R; Selwyn, J D; Lawson, J M; Gallo, M

    2017-01-01

    Video cameras recorded the diurnal visitation rates of transient (large home range) piscivorous fishes to coral patch reefs in The Bahamas and identified 11 species. Visits by bar jack Caranx ruber, mutton snapper Lutjanus analis, yellowtail snapper Ocyurus chrysurus, barracuda Sphyraena barracuda and cero Scomberomorus regalis were sufficiently frequent to correlate with a range of biophysical factors. Patch-reef visitation rates and fish abundances varied with distance from shore and all species except S. regalis were seen more frequently inshore. This pattern is likely to be caused by factors including close proximity to additional foraging areas in mangroves and on fore-reefs and higher abundances close to inshore nursery habitats. Visitation rates and abundances of C. ruber, L. analis, O. chrysurus and S. regalis also varied seasonally (spring v. winter), possibly as fishes responded to temperature changes or undertook spawning migrations. The abundance of each transient predator species on the patch reefs generally exhibited limited diurnal variability, but L. analis was seen more frequently towards dusk. This study demonstrates that the distribution of transient predators is correlated spatially and temporally with a range of factors, even within a single lagoon, and these drivers are species specific. Transient predators are considered an important source of mortality shaping reef-fish assemblages and their abundance, in combination with the biomass of resident predators, was negatively correlated with the density of prey fishes. Furthermore, transient predators are often targeted by fishers and understanding how they utilize seascapes is critical for protecting them within reserves.

  9. Equatorial decline of reef corals during the last Pleistocene interglacial

    NASA Astrophysics Data System (ADS)

    Kiessling, Wolfgang; Simpson, Carl; Beck, Brian; Mewis, Heike; Pandolfi, John M.

    2012-12-01

    The Last Interglacial (LIG; ca. 125,000 y ago) resulted from rapid global warming and reached global mean temperatures exceeding those of today. The LIG thus offers the opportunity to study how life may respond to future global warming. Using global occurrence databases and applying sampling-standardization, we compared reef coral diversity and distributions between the LIG and modern. Latitudinal diversity patterns are characterized by a tropical plateau today but were characterized by a pronounced equatorial trough during the LIG. This trough is governed by substantial range shifts away from the equator. Range shifts affected both leading and trailing edges of species range limits and were much more pronounced in the Northern Hemisphere than south of the equator. We argue that interglacial warming was responsible for the loss of equatorial diversity. Hemispheric differences in insolation during the LIG may explain the asymmetrical response. The equatorial retractions are surprisingly strong given that only small temperature changes have been reported in the LIG tropics. Our results suggest that the poleward range expansions of reef corals occurring with intensified global warming today may soon be followed by equatorial range retractions.

  10. Patch-reef morphology as a proxy for Holocene sea-level variability, Northern Florida Keys, USA

    USGS Publications Warehouse

    Brock, J.C.; Palaseanu-Lovejoy, M.; Wright, C.W.; Nayegandhi, A.

    2008-01-01

    A portion of the northern Florida Keys reef tract was mapped with the NASA Experimental Advanced Airborne Research Lidar (EAARL) and the morphology of patch reefs was related to variations in Holocene sea level. Following creation of a lidar digital elevation model (DEM), geospatial analyses delineated morphologic attributes of 1,034 patch reefs (reef depth, basal area, height, volume, and topographic complexity). Morphometric analysis revealed two morphologically different populations of patch reefs associated with two distinct depth intervals above and below a water depth of 7.7 m. Compared to shallow reefs, the deep reefs were smaller in area and volume and showed no trend in topographic complexity relative to water depth. Shallow reefs were more variable in area and volume and became flatter and less topographically complex with decreasing water depth. The knoll-like morphology of deep reefs was interpreted as consistent with steady and relatively rapidly rising early Holocene sea level that restricted the lateral growth of reefs. The morphology of shallow 'pancake-shaped' reefs at the highest platform elevations was interpreted as consistent with fluctuating sea level during the late Holocene. Although the ultimate cause for the morphometric depth trends remains open to interpretation, these interpretations are compatible with a recent eustatic sea-level curve that hindcasts fluctuating late Holocene sea level. Thus it is suggested that the morphologic differences represent two stages of reef accretion that occurred during different sea-level conditions. ?? 2008 Springer-Verlag.

  11. Carbonate particulate sedimentation and facies within the Lower Silurian Högklint patch reefs of Gotland, Sweden

    NASA Astrophysics Data System (ADS)

    Watts, Nigel R.

    1988-09-01

    Lower Wenlockian bioherms within the Högklint Formation of the Silurian, Gotland, show a myriad of carbonate particulate sedimentation which can be divided into three broad facies: inter-reef sediments, intra-reef sediments and inter-skeletal sediments. Mass wasting and normal wave action enhanced during storms, together with tidal currents, are believed to be the major mechanisms of sediment transport. Inter-reef sediments can be divided into proximal and distal deposits, with grain size and grain-support decreasing from the reef mass into the inter-reef areas. Intra-reef sediments represent sedimentation in hollows, channels and depressions on the reef surface. Grain-support of inter-skeletal sediments increase towards the top of the reefs reflecting the high water-energies that were operating outside the reefs. Graded fills, fine-scale cross- and planar-stratification, and grain size related to pore size are features which reflect the pumping action, by waves and/or tidal currents, of sediment into cavities within the Högklint patch reefs. The bioclastic sediments that are associated with the Högklint patch reefs are derived by mechanical destruction of reef knobs built by the large frame-builders, encrusting organisms and also the reef dwellers. Bioerosion is considered to have been a minor process in providing bioclastic sediment.

  12. A new record of the late Pleistocene coral Pocillopora palmata from the Dry Tortugas, Florida reef tract, USA

    USGS Publications Warehouse

    Toth, Lauren T.; Kuffner, Ilsa B.; Cheng, Hai; Edwards, R. Lawrence

    2015-01-01

    Pocilloporid corals dominated shallow-water environments in the Caribbean during much of the Cenozoic; however, the regional diversity of this family declined over the last 15 My, culminating with the extinction of its final member, Pocillopora palmata, during the latest Pleistocene. Here we present a new record of P. palmata from Dry Tortugas National Park in the Florida Keys and infer its likely age. Although most existing records of P. palmata are from the sub-aerial reef deposits of MIS5e (∼ 125 ka), the presently submerged reef in the Dry Tortugas was too deep (> 18 m) during this period to support significant reef growth. In contrast, the maximum water depth during MIS5a (∼ 82 ka) was only ∼ 5.6 m, which would have been ideal for P. palmata. Diagenetic alteration prevented direct dating of the samples; however, the similarity between the depths of the Pleistocene bedrock in the Dry Tortugas and other reefs in the Florida Keys, which have been previously dated to MIS5a, support the conclusion that P. palmata likely grew in the Dry Tortugas during this period. Our study provides important new information on the history of P. palmata, but it also highlights the vital need for more comprehensive studies of the Quaternary history of Caribbean reef development. With modern reef degradation already driving yet another restructuring of Caribbean coral assemblages, insights from past extinctions may prove critical in determining the prognosis of Caribbean reefs in the future.

  13. Diagenesis and sea level change in a Pleistocene Coral Reef, San Salvador, Bahamas

    SciTech Connect

    White, B.; Kurkjy, K.A.; Curran, H.A.

    1985-02-01

    Near the Cockburn Town reef (dated 125,000 yr B.P.), precisely surveyed bench marks are related to accurately measured mean sea level, and they provide a convenient datum plane. This coral reef developed during a sea level highstand of no more than 10,000 yr, which was insufficient time for significant subsidence; however, subsidence of approximately 3 m may have occurred since the formation of the reef. Sea level changes were caused by fluctuations in glacial-ice volume. The upper beach to dune transition, which is in the calcarenites overlying the reef, is at +4 m. A minimum highstand of +7 m is indicated when corrected for subsidence. Below +2.5 m, marine aragonite cement occurs within the intragranular pore space of the following: Halimeda plates, benthic foraminifera, Favreina (Callianassid fecal pellets), gastropods, and corals. Marine aragonite cement also occurs as intergranular isopachous rims on matrix grains of coral rubblestone. Remaining pore space was partly to completely occluded by freshwater vadose calcite cements, which occur without marine cements in the overlying shallow subtidal, beach, and dune calcarenites. No unequivocal freshwater phreatic cements, which occur without marine cements in the overlying shallow subtidal, beach, and dune calcarenites. No unequivocal freshwater phreatic cements have been found, although syntaxial overgrowths and irregular calcite rims about grains do occur in finer grained sediments where local patches of freshwater saturation occurred within the vadose zone. Later calchification, which affected all facies, is characterized by alveolar texture, whisker calcite, microsparite, rare bladed calcite spar, Microcodium, and rhizocretions.

  14. Is Echinometra viridis facilitating a phase shift on an Acropora cervicornis patch reef in Belize?

    NASA Astrophysics Data System (ADS)

    Stefanic, C. M.; Greer, L.; Norvell, D.; Benson, W.; Curran, H.

    2012-12-01

    Coral reef health is in rapid decline across the Caribbean due to a number of anthropogenic and natural disturbances. A phase shift from coral- to macroalgae-dominant reefs is pervasive and has been well documented. Acropora cervicornis (Staghorn Coral) has been particularly affected by this shift due to mass mortality of this species since the 1980s. In recent years few Caribbean A. cervicornis refugia have been documented. This study characterizes the relationship between coral and grazing urchins on a rare patch reef system dominated by A. cervicornis off the coast of Belize. To assess relative abundance of live A. cervicornis and the urchin Echinometra viridis, photographs and urchin abundance data were collected from 132 meter square quadrats along five transects across the reef. Photographs were digitized and manually segmented using Adobe Illustrator, and percent live coral cover and branch tip densities were calculated using Matlab. Mean percent live coral cover across all transects was 24.4 % with a high of 65% live coral per meter square. Average urchin density was 18.5 per quadrat, with an average density per transect ranging from 22.1 to 0.5 per quadrat. Up to over 400 live A. cervicornis branch tips per quadrat were observed. Data show a positive correlation between E. viridis abundance and live A. cervicornis, suggesting that these urchins are facilitating recovery or persistence of this endangered coral species. These results suggest the relationship between E. viridis and A. cervicornis could be a key element in a future reversal of the coral to macroalgae phase shift on some Caribbean coral reefs.

  15. Burdigalian turbid water patch reef environment revealed by larger benthic foraminifera

    NASA Astrophysics Data System (ADS)

    Novak, V.; Renema, W.; Throughflow-project

    2012-04-01

    Ancient isolated patch reefs outcropping from siliciclastic sediments are a trademark for the Miocene carbonate deposits occurring in East Kalimantan, Indonesia. They develop in transitional shelf sediments deposited between deltaic and deep marine deposits (Allen and Chambers, 1998). The Batu Putih Limestone (Wilson, 2005) and similar outcrops in adjacent areas have been characterized as shallow water carbonates influenced by high siliciclastic input, showing low relief patch reefs in turbid waters. Larger benthic foraminifera (LBF) are excellent markers for biochronology and paleoenvironmental reconstruction. This study aims to reveal age and paleoenvironment of a shallow water carbonate patch reef developed in mixed depositional system by using LBF and microfacies analysis. The studied section is located near Bontang, East Kalimantan, and is approximately 80 m long and 12 m high. It is placed within Miocene sediments in the central part of the Kutai Basin. Patch reef and capping sediments were logged through eight transects along section and divided into nine different lithological units from which samples were collected. Thin sections and isolated specimens of larger benthic foraminifera were analyzed and recognized to species level (where possible) providing age and environmental information. Microfacies analysis of thin sections included carbonate classification (textural scheme of Dunham, 1962) and assemblage composition of LBF, algae and corals relative abundance. Three environmentally indicative groups of LBF were separated based on test morphology, habitat or living relatives (Hallock and Glenn, 1986). Analysed foraminifera assemblage suggests Burdigalian age (Tf1). With use of microfacies analysis nine successive lithological units were grouped into five facies types. Paleoenvironmental reconstruction of LBF fossil assemblage indicate two cycles of possible deepening recorded in the section. Based on high muddy matrix ratio in analyzed thin-sections we

  16. Sedimentology and diagenesis of windward-facing fore-reef calcarenites, Late Pleistocene of Barbados, West Indies

    SciTech Connect

    Humphrey, J.D.; Kimbell, T.N.

    1989-03-01

    Late Pleistocene reef terraces in southeastern Barbardos developed extensive fore-reef sand facies during deposition in response to high-energy windward-facing conditions. Sedimentology and diagenesis of these deposits illustrate significant contrasts with previous studies from the leeward west coast. These calcarenites are dominantly skeletal packstones with less common grainstones and wackestones present. The fore-reef sand facies occurs within progradational reef sequences, being conformably overlain by deep-water head coral facies. Medium-bedded, laterally continuous sand sheets retain original depositional slopes, dipping seaward at 10/degrees/-15/degrees/. These fore-reef deposits, in places, are over 30 m thick (average 20 m) and developed rapidly during late Pleistocene glacio-eustatic sea level highstands. Sedimentation rate ranges from 2 to 5 m/1000 years. Areal extent of fore-reef calcarenites in southeastern Barbados is estimated to be 8-10 km/sup 2/. Lithologically, the packstones are composed of an abundance of coralline red algae and the benthic foraminifer Amphistegina sp. Other volumetrically significant allochems include echinoids, mollusks, rhodoliths, peloids, and micritized grains. Micrite in the wackestone and packstone lithologies is likely derived from intense physical/mechanical abrasion of shoal-water reef facies. Diagenesis of these lithologies reflects a complex interplay of meteoric, mixing zone, and marine environments as a result of glacio-eustasy. Differences in diagenetic character are derived from differences in terrace ages, terrace geometry, a paleotopographic control on meteoric ground-water distribution, and high-energy coastal conditions. Diagenetic fabrics include equant, blocky meteoric phreatic calcite; limpid dolomite of mixing zone origin: and peloidal and isopachous fibrous cements from marine precipitation.

  17. Caribbean Reef Response to Plio-Pleistocene Climate Change: Results of the Dominican Republic Drilling Project (DRDP)

    NASA Astrophysics Data System (ADS)

    Klaus, J.; McNeill, D. F.; Diaz, V.; Swart, P. K.; Pourmand, A.

    2014-12-01

    Caribbean reefs changed profoundly in taxonomic composition, diversity, and dominance structure during late Pliocene and Pleistocene climatic change. These changes coincide with protracted climatic deterioration and cooling between 2.0 to 0.8 Ma, and the onset of high amplitude sea-level fluctuations ~400 ka. The Dominican Republic Drilling Project (DRDP) was initiated to determine how climate change and global high-amplitude sea level changes influenced depositional patterns in Pliocene to Recent reef systems of the Caribbean. A transect of 7 core borings (~700 m total depth) were collected along the southern coast of the DR. New age constraints based on U/Th geochronometry and radiogenic Sr isotopes, combined with depositional lithofacies, faunal indicators, and stable isotope profiles have allowed us to correlate between wells and define the internal anatomy and stratal geometry of the individual reef sigmoids and sigmoid sets. Faunal records suggest most extinction occurred prior to ~1 Ma. Following this extinction, fringing reef margins of the Caribbean display a characteristic zonation in which Acropora palmata dominates shallow high-energy reef crests and Acropora cervicornis calmer fore-reef slopes and backreef lagoons. The dominance of acroporids across this zonation has been attributed to growth rates 5-100 times faster than other corals.

  18. Upwellings mitigated Plio-Pleistocene heat stress for reef corals on the Florida platform (USA)

    NASA Astrophysics Data System (ADS)

    Brachert, Thomas C.; Reuter, Markus; Krüger, Stefan; Kirkerowicz, Julia; Klaus, James S.

    2016-03-01

    The fast growing calcareous skeletons of zooxanthellate reef corals (z corals) represent unique environmental proxy archives through their oxygen and carbon stable isotope composition (δ18O, δ13C). In addition, the accretion of the skeleton itself is ultimately linked to the environment and responds with variable growth rates (extension rate) and density to environmental changes. Here we present classical proxy data (δ18O, δ13C) in combination with calcification records from 15 massive z corals. The z corals were sampled from four interglacial units of the Florida carbonate platform (USA) dated approximately 3.2, 2.9, 1.8 and 1.2 Ma (middle Pliocene to early Pleistocene). The z corals (Solenastrea, Orbicella, Porites) derive from unlithified shallow marine carbonates and were carefully screened for primary preservation suited for proxy analysis. We show that skeletal accretion responded with decreasing overall calcification rates (decreasing extension rate but increasing density) to warmer water temperatures. Under high annual water temperatures, inferred from sub-annually resolved δ18O data, skeletal bulk density was high, but extension rates and overall calcification rates were at a minimum (endmember scenario 1). Maximum skeletal density was reached during the summer season giving rise to a growth band of high density within the annually banded skeletons ("high density band", HDB). With low mean annual water temperatures (endmember scenario 2), bulk skeletal density was low but extension rates and calcification rates reached a maximum, and under these conditions the HDB formed during winter. Although surface water temperatures in the Western Atlantic warm pool during the interglacials of the late Neogene were ˜ 2 °C higher than they are in the present day, intermittent upwelling of cool, nutrient-rich water mitigated water temperatures off south-western Florida and created temporary refuges for z coral growth. Based on the sub-annually resolved δ18O and

  19. Responses of algae, corals and fish to the reduction of macroalgae in fished and unfished patch reefs of Glovers Reef Atoll, Belize

    NASA Astrophysics Data System (ADS)

    McClanahan, T.; McField, M.; Huitric, M.; Bergman, K.; Sala, E.; Nyström, M.; Nordemar, I.; Elfwing, T.; Muthiga, N.

    2001-05-01

    Macroalgae were experimentally reduced by approximately 2.5 kg/m2 on eight similar-sized patch reefs of Glovers Reef Atoll, Belize, in September 1998. Four of these reefs were in a protected "no-take" zone and four were in a "general use" fishing zone. Eight adjacent reefs (four in each management zone) were also studied as unmanipulated controls to determine the interactive effect of algal reduction and fisheries management on algae, coral, fish, and rates of herbivory. The 16 reefs were sampled five times for 1 year after the manipulation. We found that the no-fishing zone had greater population densities for 13 of 30 species of fish, including four herbivorous species, but lower herbivory levels by sea urchins. However, there was lower stony coral cover and higher macroalgal cover in the "no-take" zone, both prior to and after the experiment. There were no significant effects of management on the percent cover of fleshy macroalgae. The algal reduction resulted in an increase in six fish species, including four herbivores and two which feed on invertebrates. One species, Lutjanus griseus, declined in experimental reefs. Macroalgal biomass quickly recovered from the reduction in both management areas within a few months, and by species-level community measures within 1 year, while stony coral was reduced in all treatments. Coral bleaching and Hurricane Mitch disturbed the site at the beginning of the study period and may explain the loss of stony coral and rapid increase in erect algae. We suggest that reducing macroalgae, as a technique to restore turf and encrusting coralline algae and stony corals, may work best after reefs have been fully protected from fishing for a period long enough to allow herbivorous fish to recover (i.e. >5 years). Further ecological studies on Glovers Reef are required to understand the shift from coral to algal dominance that has occurred on this reef in the last 25 years.

  20. Upwellings mitigated Plio-Pleistocene heat stress for reef corals on the Florida platform (USA)

    NASA Astrophysics Data System (ADS)

    Brachert, T. C.; Reuter, M.; Krüger, S.; Kirkerowicz, J.; Klaus, J. S.

    2015-10-01

    The fast growing calcareous skeletons of zooxanthellate reef corals (z-corals) represent unique environmental proxy archives through their oxygen and carbon stable isotope composition (δ18O, δ13C). In addition, the accretion of the skeleton itself is ultimately linked to the environment and responds with variable growth rates (extension rate) and density to environmental changes. Here we present classical proxy data (δ18O, δ13C) in combination with calcification records from 15 massive z-corals. The z-corals were sampled from four interglacial units of the Florida carbonate platform (USA) dated approximately 3.2, 2.9, 1.8 and 1.2 Ma (middle Pliocene to early Pleistocene). The z-corals (Solenastrea, Orbicella, Porites) derive from unlithified shallow marine carbonates and were carefully screened for primary preservation suited for proxy analysis. We show that skeletal accretion was non-linear and responded with decreasing overall calcification rates (decreasing extension rate but increasing density) to warmer water temperatures. Under high annual water temperatures, inferred from subannually resolved δ18O data, skeletal bulk density was high, but extension rates and overall calcification rates were at a minimum (endmember scenario 1). Maximum skeletal density was reached during the summer season giving rise to a growth band of high density within the annually banded skeletons ("high density band", HDB). With low mean annual water temperatures (endmember scenario 2), bulk skeletal density was low but extension rates and calcification rates reached a maximum, and under these conditions the HDB formed during winter. Although surface water temperatures in the Western Atlantic warm pool during the interglacials of the late Neogene where ∼ 2 °C higher than they are in the present-day, intermittent upwelling of cool, nutrient rich water mitigated water temperatures off southwestern Florida in the middle of the Atlantic warm pool and created temporary refuges for

  1. Comparisons of the 1995 and 1998 coral bleaching events on the patch reefs of San Salvador Island, Bahamas.

    PubMed

    McGrath, Thomas A; Smith, Garriet W

    2003-06-01

    Coral patch reefs around San Salvador Island, Bahamas have been monitored with the aid of Earthwatch volunteers three times a year since 1992. During that period two significant mass bleaching events occurred: autumn 1995, and late summer 1998. Elsewhere in 1995, bleaching was caused by higher-than-normal summer sea temperatures; in San Salvador, however, temperatures were normal. In 1998 a prolonged period of higher-than-normal sea temperatures preceded bleaching on San Salvador and worldwide. During the 1995 event, one of the monitored reefs had twice the percentage of coral colonies bleached as the other two. Bleaching was more evenly distributed among the reefs during the 1998 event. In 1995 Agaricia agaricites was significantly more affected than other coral species, with almost 50% of all its colonies showing bleaching. Bleaching was more evenly spread among coral species in 1998, with five species showing bleaching on more than 40% of their colonies. Bleaching began on Millepora as early as August during the 1998 event and progressed to other species through the remainder of the autumn. In 1995 bleaching was not seen until late autumn and appeared to impact all affected species at about the same time. Recovery from the 1995 event was complete: no coral death or damage above normal background levels were seen. In the 1998 event, all Acropora cervicornis on the monitored reefs died and A. palmata was severely damaged. Millepora sp. lost almost half of their live tissue, and Montastraea sp. showed significant tissue damage following this event. Phototransect analysis suggests that more than 20% of total live tissue on affected species died during the 1998 event. A. cervicornis has demonstrated no re-growth from 1998 to 2000 on monitored reefs. Monitoring has suggested significant differences in causes and courses in these two events.

  2. Bacterial communities associated with Porites white patch syndrome (PWPS) on three western Indian Ocean (WIO) coral reefs.

    PubMed

    Séré, Mathieu G; Tortosa, Pablo; Chabanet, Pascale; Turquet, Jean; Quod, Jean-Pascal; Schleyer, Michael H

    2013-01-01

    The scleractinian coral Porites lutea, an important reef-building coral on western Indian Ocean reefs (WIO), is affected by a newly-reported white syndrome (WS) the Porites white patch syndrome (PWPS). Histopathology and culture-independent molecular techniques were used to characterise the microbial communities associated with this emerging disease. Microscopy showed extensive tissue fragmentation generally associated with ovoid basophilic bodies resembling bacterial aggregates. Results of 16S rRNA sequence analysis revealed a high variability between bacterial communities associated with PWPS-infected and healthy tissues in P. lutea, a pattern previously reported in other coral diseases such as black band disease (BBD), white band disease (WBD) and white plague diseases (WPD). Furthermore, substantial variations in bacterial communities were observed at the different sampling locations, suggesting that there is no strong bacterial association in Porites lutea on WIO reefs. Several sequences affiliated with potential pathogens belonging to the Vibrionaceae and Rhodobacteraceae were identified, mainly in PWPS-infected coral tissues. Among them, only two ribotypes affiliated to Shimia marina (NR043300.1) and Vibrio hepatarius (NR025575.1) were consistently found in diseased tissues from the three geographically distant sampling localities. The role of these bacterial species in PWPS needs to be tested experimentally.

  3. Patch dynamics of coral reef macroalgae under chronic and acute disturbance

    NASA Astrophysics Data System (ADS)

    Mumby, Peter J.; Foster, Nicola L.; Fahy, Elizabeth A. Glynn

    2005-12-01

    The patch dynamics (colonisation rate, growth rate, and extinction rate) are quantified for two dominant species of macroalgae on a Caribbean forereef in Belize: Lobophora variegata (Lamouroux) and Dictyota pulchella (Hörnig and Schnetter). Measurements were taken on time scales of days, weeks, months, and years during which three hurricanes occurred. All patches were followed on naturally occurring ramets of dead Montastraea annularis. The first hurricane (Mitch) caused massive coral mortality and liberated space for algal colonisation. The cover of Lobophora increased throughout the study and herbivores did not appear to limit its cover within a 4 year time frame. In contrast, the cover of D. pulchella fluctuated greatly and showed no net increase, despite an increase in parrotfish biomass and settlement space. Variation in the overall percent cover of an alga is not indicative of the underlying patch dynamics. The steady rise in the cover of Lobophora took place despite a high turnover of patches (12-60% of patches per year). The patch dynamics of Dictyota were slower (7-20%), but a greater patch density and threefold higher lateral growth rate led to greater fluctuations in total cover. The dynamics of algal patches are size-specific such that larger patches are less likely to become extinct during hurricanes.

  4. Topographic control and accumulation rate of some Holocene coral reefs: south Florida and Dry Tortugas

    USGS Publications Warehouse

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

    1977-01-01

    Core drilling and examination of underwater excavation on 6 reef sites in south Florida and Dry Tortugas revealed that underlying topography is the major factor controlling reef morphology. Carbon-14 dating on coral recovered from cores enables calculation of accumulation rates. Accumulation rates were found to range from 0.38 m/1000 years in thin Holocene reefs to as much as 4.85 m/1000 years in thicker buildups. Cementation and alteration of corals were found to be more pronounced in areas of low buildup rates than in areas of rapid accumulation rates. Acropora palmata, generally considered the major reef builder in Florida, was found to be absent in most reefs drilled. At Dry Tortugas, the more than 13-meter thick Holocene reef did not contain A. palmata. The principal reef builders in this outer reef are the same as those which built the Pleistocene Key Largo formation, long considered to be fossilized patch reef complex.

  5. Cold-water event of January 2010 results in catastrophic benthic mortality on patch reefs in the Florida Keys

    NASA Astrophysics Data System (ADS)

    Colella, M. A.; Ruzicka, R. R.; Kidney, J. A.; Morrison, J. M.; Brinkhuis, V. B.

    2012-06-01

    The Florida Keys are periodically exposed to extreme cold-water events that can have pronounced effects on coral reef community structure. In January 2010, the Florida Keys experienced one of the coldest 12-day periods on record, during which water temperatures decreased below the lethal limit for many tropical reef taxa for several consecutive days. This study provides a quantitative assessment of the scleractinian mortality and acute changes to benthic cover at four patch reefs in the middle and upper Keys that coincided with this cold-water event. Significant decreases in benthic cover of scleractinian corals, gorgonians, sponges, and macroalgae were observed between summer 2009 and February 2010. Gorgonian cover declined from 25.6 ± 4.6% (mean ± SE) to 13.3 ± 2.7%, scleractinian cover from 17.6 ± 1.4% to 10.7 ± 0.9%, macroalgal cover from 8.2 ± 5.2% to 0.7 ± 0.3%, and sponge cover from 3.8 ± 1.4% to 2.3 ± 1.2%. Scleractinian mortality varied across sites depending upon the duration of lethal temperatures and the community composition. Montastraea annularis complex cover was reduced from 4.4 ± 2.4% to 0.6 ± 0.2%, and 93% of all colonies surveyed suffered complete or partial mortality. Complete or partial mortality was also observed in >50% of all Porites astreoides and Montastraea cavernosa colonies and resulted in a significant reduction in cover. When compared with historical accounts of cold-water-induced mortality, our results suggest that the 2010 winter mortality was one of the most severe on record. The level of coral mortality on patch reefs is of particular concern because corals in these habitats had previously demonstrated resistance against stressors (e.g., disease and warm-water bleaching) that had negatively affected corals in other habitats in the Florida Keys during recent decades.

  6. Habitat surrounding patch reefs influences the diet and nutrition of the western rock lobster

    EPA Science Inventory

    In this study the influence of habitat on the diet and nutrition of a common reef-associated generalist consumer, the western rock lobster Panulirus cygnus, was tested. Stable isotopes (13C/12C and 15N/14N) and gut contents were used to assess the diet of lobsters collected from ...

  7. Defended territories of an aggressive damselfish contain lower juvenile coral density than adjacent non-defended areas on Kenyan lagoon patch reefs

    NASA Astrophysics Data System (ADS)

    Gordon, T. A. C.; Cowburn, B.; Sluka, R. D.

    2015-03-01

    Jewel damselfish, Plectroglyphidodon lacrymatus, aggressively defend small territories on coral reefs in which they cultivate lawns of edible macroalgae. Pairwise frequency counts showed that juvenile coral density was lower inside damselfish territories than that in adjacent non-defended areas on lagoon patch reefs in Kenya. These differences in coral density decreased as coral size increased. Direct farming effects of the damselfish and indirect inhibitory effects from higher algal densities inside territories are both thought to be potentially responsible for the results attained herein. Damselfish territories can occupy a large proportion of a coral reef; territorial behaviour in fish may have greater impacts on reef structure, in particular the resilience and growth rate of juvenile corals, than previously appreciated.

  8. Age of -360-m reef terrace, Hawaii, and the rate of late Pleistocene subsidence of the island

    SciTech Connect

    Szabo, B.J.; Moore, J.G.

    1986-11-01

    Observations from a manned submersible vehicle indicate that the -360-m reef terrace northwest of the island of Hawaii is a drowned coral reef. The preferred uranium-series age of coralline algae collected from the reef face is 120 +/- 5 ka. This age agrees with the notion that the reef was drowned during the sea-level rise following the major lowstand of the sea that occurred at 145 ka (oxygen isotope stage 6). This drowning pattern is similar to the previously determined radiocarbon age of 13 ka for drowning of the -150-m reef off west Hawaii, which drowned during the sea-level rise following the last major lowstand of the sea at 18 ka (oxygen isotope stage 2). Estimated average subsidence of the reef site off northwest Hawaii is 2.7 mm/yr since final drowning of the -360-m reef.

  9. Late Pleistocene stratigraphy of a carbonate platform margin, Exumas, Bahamas

    NASA Astrophysics Data System (ADS)

    Aalto, K. R.; Dill, Robert F.

    1996-05-01

    Detailed field studies of the southern Exuma Cays on the eastern margin of the Great Bahama Bank show a complex history of late Pleistocene island construction. Pleistocene rocks include island core eolianites, overlain at island margins by fossil patch reefs and reef sands, which in turn are overlain by, and/or grade laterally into, talus breccia cones derived from the erosion of island core eolianite at paleo-seacliffs situated at approximately 5-6 m above present mean high tide. Laminated pedogenic calcrete widely caps Pleistocene rocks. Minor zones of penetrative subsurface calcretization, developed in association with root growth, occur along permeable horizons, including: contacts between talus units or crossbed sets, along tension joints, and (possibly) at the Pleistocene reef-eolianite contact. Among Pleistocene eolianite samples studied in thin-section, the relative proportions of ooids-intraclasts+grapestones-skeletal grains-peloids are approximately 48:39:6:7. Marginal to the Exuma Sound and on the Brigantine Cays, a greater proportion of ooids have peloidal nuclei and cortices with numerous laminae, which may reflect ooid derivation from shelf margin and broad platform interior regions that were characterized by high wave energy during ooid formation. Between these two areas, ooids are more commonly superficial and have cortices with few laminae and nuclei composed of subrounded micrite or pelmicrite intraclasts. Such ooid nuclei are most likely derived from storm erosion of partially cemented seafloor muds. Some skeletal-rich eolianite in this region may reflect local sediment input from platform margin reefs, or may be part of an older(?) stratigraphic unit.

  10. Modern sediments and Pleistocene reefs from isolated carbonate platforms (Iles Eparses, SW Indian Ocean): A preliminary study

    NASA Astrophysics Data System (ADS)

    Jorry, Stéphan J.; Camoin, Gilbert F.; Jouet, Gwénaël; Roy, Pascal Le; Vella, Claude; Courgeon, Simon; Prat, Sophie; Fontanier, Christophe; Paumard, Victorien; Boulle, Julien; Caline, Bruno; Borgomano, Jean

    2016-04-01

    Isolated carbonate platforms occur throughout the geologic record, from Archean to present. Although the respective roles of tectonics, sediment supply and sea-level changes in the stratigraphical architecture of these systems are relatively well constrained, the details of the nature and controls on the variability of sedimentological patterns between and within individual geomorphologic units on platforms have been barely investigated. This study aims at describing and comparing geomorphological and sedimentological features of surficial sediments and fossil reefs from three isolated carbonate platforms located in the SW Indian Ocean (Glorieuses, Juan de Nova and Europa). These carbonate platforms are relatively small and lack continuous reef margins, which have developed only on windward sides. Field observations, petrographic characterization and grain-size analyses are used to illustrate the spatial patterns of sediment accumulation on these platforms. The internal parts of both Glorieuses and Juan de Nova platforms are blanketed by sand dunes with medium to coarse sands with numerous reef pinnacles. Skeletal components including coral, green algae, and benthic foraminifera fragments prevail in these sediments. Europa platform exhibits a similar skeletal assemblage dominated by coral fragments, with the absence of wave-driven sedimentary bodies. Fossil reefs from the Last interglacial (125,000 years BP) occur on the three platforms. At Glorieuses, a succession of drowned terraces detected on seismic lines is interpreted as reflecting the last deglacial sea-level rise initiated 20,000 years ago. These findings highlight the high potential of these platforms to study past sea-level changes and the related reef response, which remain poorly documented in the SW Indian Ocean.

  11. Cosmogenic 3He exposure ages of Pleistocene debris flows and desert pavements in Capitol Reef National Park, Utah

    NASA Astrophysics Data System (ADS)

    Marchetti, David W.; Cerling, Thure E.

    2005-04-01

    The Quaternary history of the Capitol Reef area, Utah, is closely linked to the basaltic-andesite boulder deposits that cover much of the landscape. Understanding the age and mode of emplacement of these deposits is crucial to deciphering the Quaternary evolution of this part of the Colorado Plateau. Using cosmogenic 3He exposure age dating, we obtained apparent exposure ages for several key deposits in the Capitol Reef area. Coarse boulder diamicts capping the Johnson Mesa and Carcass Creek Terraces are not associated with the Bull Lake glaciation as previously thought, but were deposited 180±15 to 205±17 ka (minimum age) and are the result of debris flow deposition. Desert pavements on the Johnson Mesa surface give exposure ranging from 97±8 to 159±14 ka and are 34-96 kyears younger than the boulder exposure ages. The offset between the boulder and pavement exposure ages appears to be related to a delay in pavement formation until the penultimate glacial/interglacial transition or periodic burial and exposure of pavement clasts since debris flow deposition. Incision rates for the Capitol Reef reach of the Fremont River calculated from the boulder exposure ages range from 0.40 to 0.43 m kyear -1 (maximum rates) and are some of the highest on the Colorado Plateau.

  12. The functional importance of Acropora austera as nursery areas for juvenile reef fish on South African coral reefs

    NASA Astrophysics Data System (ADS)

    Floros, C.; Schleyer, M. H.

    2017-03-01

    Many coral reef fish species use mangrove and seagrass beds as nursery areas. However, in certain regions, the absence or scarcity of such habitats suggests that juvenile coral reef fish may be seeking refuge elsewhere. The underlying biogenic substratum of most coral reefs is structurally complex and provides many types of refuge. However, on young or subtropical coral reefs, species may be more reliant on the living coral layer as nursery areas. Such is the case on the high-latitude coral reefs of South Africa where the coral communities consist of a thin veneer of coral overlaying late Pleistocene bedrock. Thus, the morphology of coral species may be a major determinant in the availability of refuge space. Acropora austera is a branching species that forms large patches with high structural complexity. Associated with these patches is a diverse community of fish species, particularly juveniles. Over the past decade, several large (>100 m2) A. austera patches at Sodwana Bay have been diminishing for unknown reasons and there is little evidence of their replacement or regrowth. Seven patches of A. austera (AP) and non- A. austera (NAP) were selected and monitored for 12 months using visual surveys to investigate the importance of AP as refugia and nursery areas. There were significant differences in fish communities between AP and NAP habitats. In total, 110 species were recorded within the patches compared to 101 species outside the patches. Labrids and pomacentrids were the dominant species in the AP habitats, while juvenile scarids, acanthurids, chaetodons and serranids were also abundant. The diversity and abundance of fish species increased significantly with AP size. As the most structurally complex coral species on the reefs, the loss of APs may have significant implications for the recruitment and survival of certain fish species.

  13. Development of a Pliocene mixed-carbonate siliciclastic reef (Limon, Costa Rica)

    NASA Astrophysics Data System (ADS)

    Bauch, Thorsten; Reijmer, John J. G.; McNeill, Donald F.; Schäfer, Priska

    2011-07-01

    The Miocene to Pleistocene Limon Group of Costa Rica is a mixed carbonate-siliciclastic succession that formed in association with the emergence of the Central American Isthmus. Our study focuses on a lower Late Pliocene reef unit, the newly excavated Contact Cut, which is located at the contact between the siliciclastic sediments of the Rio Banano Formation and the mixed reefal and coral bearing deposits and siliciclastic sediments of the Quebrada Chocolate Formation. The siliciclastic sediments were deposited in a thick, deltaic setting sourced by erosion of the Cordillera de Talamanca. Deposits of the Limon Group preserve a sequence of progressively shallowing, near-shore sediments that were exposed by uplift during the early to middle Pleistocene. The Contact Cut outcrop shows the first reef sequence in the stratigraphic sequence and thus illustrates the reestablishment of Caribbean coral reef predominance in the Neogene. It shows extensive reef growth during a rise in sea level and a slight progradation during the succeeding sea-level highstand. Three stages of reef evolution are recognized based on faunal diversity. The Contact Cut reef complex is comparable to the time equivalent reef of the Las Islas roadcut, situated west of Limon, which shows a rapid burial of the corals by siliciclastics. Both reefs document a distinct facies diversification during the final stages of the closing of the Central American Seaway. The reefs developed in an environment stressed by siliciclastic input, which ultimately caused a decrease in coral diversity and abundance followed by a temporary demise of the reefs. The biotic composition of the patch reefs that occurred during the sea-level rise, Las Islas and Contact Cut, did not differ from the reefs that developed during the final highstand in sea level, the reefs of the overlying Moin formation (Limon Group). Differences in the position on the shelf relative to the source of the siliciclastics might have been the cause for

  14. New maps, new information: Coral reefs of the Florida keys

    USGS Publications Warehouse

    Lidz, B.H.; Reich, C.D.; Peterson, R.L.; Shinn, E.A.

    2006-01-01

    A highly detailed digitized map depicts 22 benthic habitats in 3140.5 km2 of the Florida Keys National Marine Sanctuary. Dominant are a seagrass/lime-mud zone (map area 27.5%) throughout Hawk Channel and seagrass/carbonate-sand (18.7%) and bare carbonate-sand (17.3%) zones on the outer shelf and in The Quicksands. A lime-mud/seagrass-covered muddy carbonate-sand zone (9.6%) abuts the keys. Hardbottom communities (13.2%) consist of bare Pleistocene coralline and oolitic limestone, coral rubble, and senile coral reefs. Smaller terrestrial (4.0%) and marine habitats, including those of live coral (patch reefs, 0.7%), account for the rest (13.7%) of the area. Derived from aerial photomosaics, the seabed dataset fits precisely when transposed onto a newly developed National Geophysical Data Center hydrographic-bathymetry map. Combined, the maps point to new information on unstudied seabed morphologies, among them an erosional nearshore rock ledge bordering the seaward side of the Florida Keys and thousands of patch-reef clusters aligned in mid-Hawk Channel. Preliminary indications are that the ledge may represent the seaward extent of the 125-ka Key Largo and Miami Limestone that form the keys, and the patch reefs colonized landward edges of two noncoralline, non-dune-ridge topographic troughs. The troughs, their substrate, and inner-shelf location along the seaward side of the Hawk Channel bedrock depression are the first of that type of nuclei to be recognized in the Florida reef record. Together, the map datasets establish the efficacy and accuracy of using aerial photographs to define in extraordinary detail the seabed features and habitats in a shallow-reef setting.

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2014-05-21

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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.

  18. An overview of Miocene reefs

    SciTech Connect

    Jordan, C.F. Jr. ); Colgan, M.W. ); Frost, S.H. ); Glenn, E.C. ); Bosence, D. ); Esteban, M. )

    1990-05-01

    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.

  19. Palaeoecology of well-preserved coral communities in a siliciclastic environment from the Late Pleistocene (MIS 7), Kish Island, Persian Gulf (Iran): the development of low-relief reef frameworks (biostromes) in increasingly restricted environments

    NASA Astrophysics Data System (ADS)

    Mossadegh, Zahra Karimi; Parker, Justin; Gischler, Eberhard; Oschmann, Wolfgang; Blakeway, David; Eisenhauer, Anton

    2013-03-01

    Major changes in community structure and depositional relief of high-latitude coral communities in the southern Persian Gulf between marine isotope stage (MIS) 7 and the present day suggest that the area has become increasingly restricted. Corals and bivalves from outcrops on Kish Island, Iran, were identified in order to interpret the Late Pleistocene palaeoenvironmental setting. U/Th disequilibrium dating was used to constrain the ages of the stratigraphic units. During MIS 7, two coral-bearing sequences were deposited on what is now Kish Island. The lower sequence is dated as MIS 7.5 and changes laterally from an assemblage dominated by Cyphastrea sp. and Platygyra daedalea in the west to one characterized by branching Montipora in the east. By contrast, the upper sequence, dated as MIS 7.1, transitions from an assemblage dominated by platy Montipora in the west to a diverse assemblage of Platygyra and other faviids in the east. The assemblages of both sequences are within a marl matrix and bounded by thin lithified mollusc-rich layers. Corals and bivalves indicate that the sequences were deposited on gentle slopes in sheltered environments less than 20 m deep. The MIS 7 deposits may be classified as coral carpets or biostromes that developed a low-relief framework. During MIS 5, coral communities were no longer framework building and are now limited to an Acropora-rich layer of coral rubble that covers large parts of the island, and two small incipient reefs with sparse faviids. Similarities between the MIS 5 and modern nearshore coral communities suggest that the environmental conditions during MIS 5 were comparable to those of today. The late Pleistocene coral carpets and non-framework coral communities of the southern Persian Gulf may serve as models for coral biostromes in the fossil record, which formed under restricted environmental conditions such as elevated terrigenous input, high turbidity, and strong seasonal changes in temperature and/or salinity.

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

    NASA Astrophysics Data System (ADS)

    Purdy, Edward G.; Winterer, Edward L.

    2006-02-01

    The Darwinian progressive subsidence model for the evolution of fringing reefs, barrier reefs and atolls has been generally accepted following the indisputable proof of subsidence provided by drilling results in the Pacific. Nonetheless, there are data that do not fit the expectations of the model, such as the similar lagoon depths of barrier reefs and atolls as opposed to the subsidence theory’s implicit prediction that atolls should have significantly greater depths. In contrast, a great deal of evidence supports the influence of meteoric solution on barrier reef morphology. For example, the maximum lagoon depth of 56 modern barrier reefs is statistically correlated with the lagoon catchment area for modern annual rainfall. These modern rainfall patterns would seem to be a reasonable proxy for relative geographic differences in glacial lowstand rainfall, even though the absolute amounts of such rainfall are unknown. The correlation therefore suggests the importance of Pleistocene subaerial solution in contributing to barrier reef morphology. Further support for antecedent influence occurs in the form of barrier reef passes in which the depth of the reef pass is correlated with onshore drainage volumes. On a larger scale, the Cook Island of Mangaia provides evidence that solution can produce barrier reef morphology independent of reef development. In contrast, there are no examples of the subsidence-predicted lagoon transition of fringing reefs to barrier reefs to atolls. Moreover, the common occurrence of fringing reefs within barrier reefs negates subsidence as a causal factor in their ‘presumed progressive evolutionary development. Consequently, the evidence to date suggests that a solution morphology template has been accentuated by reef construction to produce the diagnostic barrier reef morphology we see today. The importance of subsidence would seem to be in accounting for the overall thickness of the resulting carbonate caps of oceanic examples and in

  1. Coral reef hydrogeology

    SciTech Connect

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

    1985-05-21

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

  2. Phylogeography of the reef fish Cephalopholis argus (Epinephelidae) indicates Pleistocene isolation across the indo-pacific barrier with contemporary overlap in the coral triangle

    PubMed Central

    2011-01-01

    Background The Coral Triangle (CT), bounded by the Philippines, the Malay Peninsula, and New Guinea, is the epicenter of marine biodiversity. Hypotheses that explain the source of this rich biodiversity include 1) the center of origin, 2) the center of accumulation, and 3) the region of overlap. Here we contribute to the debate with a phylogeographic survey of a widely distributed reef fish, the Peacock Grouper (Cephalopholis argus; Epinephelidae) at 21 locations (N = 550) using DNA sequence data from mtDNA cytochrome b and two nuclear introns (gonadotropin-releasing hormone and S7 ribosomal protein). Results Population structure was significant (ΦST = 0.297, P < 0.001; FST = 0.078, P < 0.001; FST = 0.099, P < 0.001 for the three loci, respectively) among five regions: French Polynesia, the central-west Pacific (Line Islands to northeastern Australia), Indo-Pacific boundary (Bali and Rowley Shoals), eastern Indian Ocean (Cocos/Keeling and Christmas Island), and western Indian Ocean (Diego Garcia, Oman, and Seychelles). A strong signal of isolation by distance was detected in both mtDNA (r = 0.749, P = 0.001) and the combined nuclear loci (r = 0.715, P < 0.001). We detected evidence of population expansion with migration toward the CT. Two clusters of haplotypes were detected in the mtDNA data (d = 0.008), corresponding to the Pacific and Indian Oceans, with a low level of introgression observed outside a mixing zone at the Pacific-Indian boundary. Conclusions We conclude that the Indo-Pacific Barrier, operating during low sea level associated with glaciation, defines the primary phylogeographic pattern in this species. These data support a scenario of isolation on the scale of 105 year glacial cycles, followed by population expansion toward the CT, and overlap of divergent lineages at the Pacific-Indian boundary. This pattern of isolation, divergence, and subsequent overlap likely contributes to species richness at the adjacent CT and is consistent with the region

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

    NASA Astrophysics Data System (ADS)

    Purdy, E.; Winterer, E. L.

    2004-05-01

    The Darwinian progressive subsidence model for the evolution of fringing reefs, barrier reefs and atolls has been generally accepted following the indisputable proof of subsidence provided by drilling results in the Pacific. Nonetheless, there are data that do not fit the expectations of the model, such as the similar lagoon depths of barrier reefs and atolls as opposed to the subsidence theory's implicit prediction that atolls should have significantly greater depths. In contrast, much evidence supports the influence of meteoric-water solution on barrier reef morphology. For example, the maximum lagoon depth of the 56 modern barrier reefs is statistically correlated with the lagoon catchment area for modern annual rainfall. These modern rainfall patterns are a reasonable proxy for relative geographic differences in glacial lowstand rainfall, even though the absolute amounts of such rainfall are unknown. The correlation therefore stongly suggests the importance of Pleistocene subaerial solution in contributing to barrier reef morphology. Further support for antecedent influence occurs in the form of barrier reef passes in which the depth of the reef pass is correlated with onshore drainage volumes. On a larger scale, the Cook Island of Mangaia provides evidence that solution can produce barrier reef morphology independent of reef development. In contrast, there are no examples of the Darwinian subsidence-predicted lagoon transition of fringing reefs to barrier reefs to atolls. Moreover, the common occurrence of fringing reefs within barrier reefs negates subsidence as a causal factor in their presumed progressive evolutionary development. Consequently, the evidence points to a solution morphology template which has been accentuated by reef construction to produce the diagnostic barrier reef morphology we see today. Rapid subsidence of seamounts by flexural loading during their early history, combined with Pleistocene sealevel fluctuations results in permanent

  4. Growth of Pleistocene massive corals in south Florida: low skeletal extension-rates and possible ENSO, decadal, and multi-decadal cyclicities

    NASA Astrophysics Data System (ADS)

    Gischler, E.; Hudson, J. H.; Storz, D.

    2009-12-01

    Skeletal extension-rates and their variability are significantly lower in Pleistocene massive reef-building corals ( Montastraea annularis group) in south Florida as compared with modern corals of the same taxa in the same study area. We analyzed 1,429 annual increments in 18 cores of Montastraea colonies from Windley Key and the Key Largo Waterway in the late Pleistocene Key Largo Limestone, which was deposited during marine isotope stage 5e (ca. 125 kyrs BP). The average extension-rate is 5.2 mm/year, which is about half the value known for modern Montastraea in shallow water reef environments. With an average standard deviation (SD) of 1.01, the variability of extension-rates is at the lower range limit of modern Montastraea in south Florida (SD = 1-3.6). Due to the higher sea level, the Pleistocene Key Largo patch reef trend was located on a large carbonate platform. Unlike today, the island chain of the Florida Keys, which function as a shelter for the Florida Reef Tract from inimical bank water, was not in existence. Corals probably grew under higher-than-present sea surface temperatures, which resulted in comparably low skeletal extension-rates. The detection of 3-7 year, decadal, and multi-decadal cyclicities in extension-rate time series suggests that the major modes of modern tropical climate variability such as the El Niño-Southern Oscillation (ENSO) and possibly the Atlantic Multidecadal Oscillation (AMO) were in effect during the last interglacial.

  5. Small-Boat Noise Impacts Natural Settlement Behavior of Coral Reef Fish Larvae.

    PubMed

    Simpson, Stephen D; Radford, Andrew N; Holles, Sophie; Ferarri, Maud C O; Chivers, Douglas P; McCormick, Mark I; Meekan, Mark G

    2016-01-01

    After a pelagic larval phase, settlement-stage coral reef fish must locate a suitable reef habitat for juvenile life. Reef noise, produced by resident fish and invertebrates, provides an important cue for orientation and habitat selection during this process, which must often occur in environments impacted by anthropogenic noise. We adapted an established field-based protocol to test whether recorded boat noise influenced the settlement behavior of reef fish. Fewer fish settled to patch reefs broadcasting boat + reef noise compared with reef noise alone. This study suggests that boat noise, now a common feature of many reefs, can compromise critical settlement behavior of reef fishes.

  6. Pearl and Hermes Reef, Hawaiian Island Chain

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Pearl and Hermes Reef (28.0N, 176.0W) in the Hawaiian Island Chain, are seen with several small sandy islands, forming an atoll that caps a seamount on the long chain that extends some 1,500 miles northwestward from the more familiar Hawaiian Islands proper. Pearl and Hermes Reef lies about 100 miles southeast of Midway island. A reticulate network of coral patch reefs separates the lagoon into more or less isolated pools.

  7. Patch tests*

    PubMed Central

    Lazzarini, Rosana; Duarte, Ida; Ferreira, Alessandra Lindmayer

    2013-01-01

    Patch tests were introduced as a diagnostic tool in the late nineteenth century. Since then, they have improved considerably becoming what they are today. Patch tests are used in the diagnostic investigation of contact dermatitis worldwide. Batteries or series previously studied and standardized should be used in patch testing. The methodology is simple, but it requires adequate training for the results to be correctly interpreted and used. Despite having been used for over a century, it needs improvement like all other diagnostic techniques in the medical field. PMID:24474094

  8. Ancient reef ecosystem expansion and collapse

    NASA Astrophysics Data System (ADS)

    Copper, P.

    1994-01-01

    Platform carbonate and, particularly, reef ecosystem development (with reefs representing the acme of carbonate platform growth) were highly cyclical in early to mid Paleozoic time, especially in relation to known or postulated times of global warming or cooling. These cycles do not appear to correspond to postulated 26 Ma rhythms seen in diversity patterns, nor were they regular. There were major periods of worldwide reef expansion (e.g. mid-Silurian-Late Devonian), corresponding to global warming well above present day norms, and periods of complete global reef collapse (e.g., mid-Cambrian to mid-Ordovician, Late Devonian) corresponding to global perturbations. At times of major reef expansion in the Paleozoic, areas covered by equatorial reef and inter-reef carbonate platforms are conservatively estimated to have periodically exceeded 5 million sq. km, nearly ten times that in the modern ocean. At times of global reef collapse, e.g. the Famennian (Late Devonian), reef complexes were completely absent or, at best, covered <1000 sq. km. The chief factors relating to periodic collapse and mass extinction of reef biotas appear to be related to climatic change and possibly ocean anoxic events, in turn as a response to large scale, geologically disruptive factors such as plate collisions, plate movement across equatorial belts and volcanism. Stress “signals” in Cambrian through Cretaceous reef ecosystems appear to be comparable to those of today: whether these relate to physical versus biological stress is uncertain. Reef stress is evident in globally reduced areas and thicknesses of reef carbonate production, the absence of large scale barrier reef systems and reduction to smaller patch reef complexes (or, periodically, following mass extinctions, no reefs at all), reduced species and genus diversity, small skeletons or colonies, limited or no biotic zonation along reef transects, and arrested succession and ecologic replacement of complex, more highly evolved

  9. Coral reefs of the Mascarenes, Western Indian Ocean.

    PubMed

    Turner, John; Klaus, Rebecca

    2005-01-15

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

  10. Last interglacial reef growth beneath Belize barrier and isolated platform reefs

    NASA Astrophysics Data System (ADS)

    Gischler, Eberhard; Lomando, Anthony J.; Hudson, J. Harold; Holmes, Charles W.

    2000-05-01

    We report the first radiometric dates (thermal-ionization mass spectrometry) from late Pleistocene reef deposits from offshore Belize, the location of the largest modern reef complex in the Atlantic Ocean. The results presented here can be used to explain significant differences in bathymetry, sedimentary facies, and reef development of this major reef area, and the results are significant because they contribute to the knowledge of the regional geology of the eastern Yucatán. The previously held concept of a neotectonically stable eastern Yucatán is challenged. The dates indicate that Pleistocene reefs and shallow-water limestones, which form the basement of modern reefs in the area, accumulated ca. 125 130 ka. Significant differences in elevation of the samples relative to present sea level (>10 m) have several possible causes. Differential subsidence along a series of continental margin fault blocks in combination with variation in karstification are probably the prime causes. Differential subsidence is presumably related to initial extension and later left-lateral movements along the adjacent active boundary between the North American and Caribbean plates. Increasing dissolution toward the south during Pleistocene sea-level lowstands is probably a consequence of higher precipitation rates in mountainous southern Belize.

  11. Last interglacial reef growth beneath Belize barrier and isolated platform reefs

    USGS Publications Warehouse

    Gischler, Eberhard; Lomando, Anthony J.; Hudson, J. Harold; Holmes, Charles W.

    2000-01-01

    We report the first radiometric dates (thermal-ionization mass spectrometry) from late Pleistocene reef deposits from offshore Belize, the location of the largest modern reef complex in the Atlantic Ocean. The results presented here can be used to explain significant differences in bathymetry, sedimentary facies, and reef development of this major reef area, and the results are significant because they contribute to the knowledge of the regional geology of the eastern Yucatán. The previously held concept of a neotectonically stable eastern Yucatán is challenged. The dates indicate that Pleistocene reefs and shallow-water limestones, which form the basement of modern reefs in the area, accumulated ca. 125–130 ka. Significant differences in elevation of the samples relative to present sea level (>10 m) have several possible causes. Differential subsidence along a series of continental margin fault blocks in combination with variation in karstification are probably the prime causes. Differential subsidence is presumably related to initial extension and later left-lateral movements along the adjacent active boundary between the North American and Caribbean plates. Increasing dissolution toward the south during Pleistocene sea-level lowstands is probably a consequence of higher precipitation rates in mountainous southern Belize.

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

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

    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.

  13. Granisetron Transdermal Patch

    MedlinePlus

    ... patch. Each patch is stuck onto a thin plastic liner and a separate rigid plastic film. Do not open the pouch in advance, ... cut the patch into pieces. Peel the thin plastic liner off of the printed side of the ...

  14. Great Barrier Reef

    Atmospheric Science Data Center

    2013-04-16

    article title:  Australia's Great Barrier Reef     View Larger Image ... reef, but a vast maze of reefs, passages, and coral cays (islands that are part of the reef). This nadir true-color image was acquired by ...

  15. Cabbage Patch

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This Sojourner rover image of the Cabbage Patch shows small rounded objects on the surface that are about 3-4 cm across. Some of these are within excavations, which are about 0.5 cm wide. Several questions arise about the pebbles: Why are they rounded? Where did they come from? What do they mean?

    Geologists use MULTIPLE WORKING HYPOTHESES when attempting to explain observations. Some hypotheses that could account for the pebbles are: They were rounded during transport by waters of catastrophic floods and deposited on the Ares Vallis floodplain They were rounded by wave action on an ancient Martian beach They were rounded during glacial transport They are glasses that were produced by melting during impact cratering. The glass was first ejected from the crater, then molded into spherical shapes or drops as it traveled through the atmosphere, and finally was deposited at the sites They are spatter from lava flows They are nodules brought up from the deep Martian interior by lava flows or pyroclastic eruptions. They are concretions formed in sedimentary rocks They came from ancient conglomerate rocks. The pebbles were rounded by water action and subsequently lithified into conglomerate rocks. Later, the waters of catastrophic floods transported the conglomerates and deposited them on the Ares floodplain. The pebbles were then freed from the rocks by weathering. A combination of the above

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

  16. Extended Late Pleistocene Sea Level Record

    NASA Astrophysics Data System (ADS)

    Fairbanks, R. G.; Cao, L.; Mortlock, R. A.

    2006-12-01

    Several hundred new closed system 230Th/234U and radiocarbon dates and the addition of more cores and coral samples from the islands of Barbados, Kiritimati and Araki contribute to an enhanced sea level record for the late Pleistocene ranging from the present to 240,000 yrs BP. Application of more rigorous sample screening criteria, including redundant 231Pa/235U dates have resulted in more closed system ages and better sea level resolution. In addition, a multibeam survey has mapped an extensive glacial lowstand reef on a ridge south of Barbados that is capped by a set of pinnacle reefs that grew during the early deglaciation. Among our new observations, the more detailed Barbados sea level record now resolves a Younger Dryas still- stand and a sea level drop between 16,140 and 14,690, overlapping the timing of H1 by some age estimates. The coral ages bracketing melt water pulse 1A have been further refined to 14,082 +/- 28 yrs BP and 13,632 +/- 32 yrs BP (2-sigma). The Isotope Stage 3 interstadial ended with sea level near 87.5 meters below present at 29,500 years ago before dropping to full glacial levels. The last glacial sea level lowstand began as early as 26,000 yrs BP. Extensive dating of Marine Isotope Stage 3 interstadial reefs on the islands of Araki and Barbados have added considerable resolution to this time interval and reliably bracket lowstand intervals separating the interstadials. A new diagenesis model has improved our prospecting success for closed system ages from older reefs and added some critical dates to the sparse closed-system data set for MIS-5 and MIS-7 high stand reefs..

  17. Miocene reef facies of pelagian block, central Mediterranean

    SciTech Connect

    Pedley, H.M.

    1988-02-01

    Miocene reefs outcrop in the Maltese Islands, southeastern Sicily, and the pelagian island of Lampedusa. Several rapid eustatic sea level fluctuations affected these late Tortonian-early Messinian build-ups; normal salinities appear to have been maintained during these events. In addition to sea floor topography, reef development appears to have been controlled by turbulence. Encruster-dominated patch reefs are typical of platform and shallow ramp situations where turbulence is high. Branching and massive coral assemblages are typical of fore-reef curtains and steep slope substrates.

  18. Pulley reef: a deep photosynthetic coral reef on the West Florida Shelf, USA

    USGS Publications Warehouse

    Culter, J.K.; Ritchie, K.B.; Earle, S.A.; Guggenheim, D.E.; Halley, R.B.; Ciembronowicz, K.T.; Hine, A.C.; Jarrett, B.D.; Locker, S.D.; Jaap, W.C.

    2006-01-01

    Pulley Reef (24°50′N, 83°40′W) lies on a submerged late Pleistocene shoreline feature that formed during a sea-level stillstand from 13.8 to 14.5 ka (Jarrett et al. 2005). The reef is currently 60–75 m deep, exhibits 10–60% coral cover, and extends over approximately 160 km2 of the sea floor. Zooxanthellate corals are primarily Agaricia lamarcki, A. fragilis, Leptoseris cucullata, and less common Madracis formosa, M. pharensis, M. decactis, Montastraea cavernosa, Porites divaricata, Scolymia cubensis and Oculina tenella. Coralline algae are comparable in abundance to stony corals. Other macroalgae include Halimeda tuna, Dictyota divaricata, Lobophora variegata, Ventricatri ventricosa, Verdigelas pelas, and Kallymenia sp. Anadyomene menziesii is abundant. The reef provides a habitat for organisms typically observed at much shallower depths, and is the deepest known photosynthetic coral reef on the North America continental shelf (Fig. 1).

  19. Influence of constituent composition and texture on mineralogy and diagenesis of reef sediments

    SciTech Connect

    Boss, S.K.; Liddell, W.D.

    1985-01-01

    The close juxtaposition of Holocene and Pleistocene (120,000 y.b.p.) fringing reef deposits along the Jamaican north coast provides an excellent opportunity for the development of models relating original sediment mineralogies and textures to diagenetic alteration of carbonate sediments. Constituent composition controls initial mineralogies of the reef sediments. X-ray diffraction analyses of Holocene reef sediments reveal that aragonite is the most abundant carbonate phase (49-89%), followed by high-Mg calcite (8-46%) and low-Mg calcite (2-12%). Original sediment textural characteristics influence the diagenesis of these deposits. Analyses of Pleistocene back reef and shallow (5-8m) fore reef facies indicate that surface exposures of the back reef facies retain much of their original aragonite and high-Mg calcite, but surface exposures of the fore reef facies have undergone extreme diagenetic alteration to low-Mg calcite. Differential diagenesis of these deposits is attributed to variability initial sorting and permeability of back reef and fore reef sediments. Poorer sorting and reduced permeability of the back reef deposits has restricted fluid flow and concomitant conversion of metastable carbonate phases has been inhibited. Conversely, the better sorting and higher initial permeability of fore reef facies sediments has resulted in increased fluid migration, greater dissolution of aragonite and high-Mg calcite, and reprecipitation of low-Mg calcite in conjunction with the development of a 1m thick caliche cap.

  20. Hurricane impact on lagoonal reefs - implications for recognition of ancient storm deposits

    SciTech Connect

    Bonem, R.M.

    1985-01-01

    During August 1080, Hurricane Allen passed along the north coast of Jamaica. Although several previous investigations have documented the effects of this hurricane on the fore reef and reef crest, this study presents the first detailed description of the storm impact on lagoonal patch reefs in Discovery Bay. In contrast to the damage described on the fore reef and reef crest, the patch reefs received only minor temporary damage to reef framework due to breakage and increased sedimentation. These effects could be recognized only by examination of bathymetric and zonal maps constructed during the last 10 years. However, hurricane impact on the sedimentologic record was readily observed in cores taken along transects of lagoonal patch reefs. Although in general, shallow reef zones had abnormally great amounts of fine sediment and deeper zones showed increased coarse material, other patterns could be documented and made recognition of storm deposits and distinction of these deposits from artificial disturbance relatively easy. Because lagoonal patch reefs may serve as models for many ancient bioherms, this study provides new evidence that may be used to recognize ancient storm deposits associated with bioherms in carbonate mud environments.

  1. Setting of and mixed carbonate-siliciclastic facies associated with Holocene nearshore sabellid worm reefs, northern Belize

    SciTech Connect

    Mazzullo, S.J.; Burke, C.D.; Dunn, R.K.; bischoff, W.D. )

    1990-05-01

    Communities of sabellid worms (Polychaeta) in northern Belize (mouth of Northern River Lagoon) occur as areally discontinuous, unlithified patch reefs cresting positive features on an irregular depositional topography of Holocene and older sediments. They are found in nearshore marine, moderate energy, tidally influenced environments (intertidal to 60-cm depths) of normal salinity (36%) adjoining subtidal deposits. These colonies, as much as 30 cm thick, are composed of dense thickets of agglutinating worm tubes (1.0 mm diameter, 3.0 cm long) that trap and bind sand to silt-size bioclastic debris and micrite. Worm population density in these communities averages 30 tubes/cm{sup 2}. The antecedent depositional topography beneath the worm reefs and subjacent to adjoining Holocene deposits is characterized by ridges oriented normal to the present shoreline. These ridges are held up by pre-Holocene (latest Pleistocene ) terrigenous sands of probably fluvial distributary origin, occurring at approximately 2.0 m in the subsurface. The overlying Holocene deposits on these ridges are 2.0 m thick and consist of a general upward-coarsening section of terrigenous sandy, carbonate sandy muds to muddy sands punctuated by mangrove peats and capped by the worm reefs. Low areas on the antecedent topography are presently the sites of deposition of deeper subtidal (1.0 m), muddy carbonate sands with some admixed, reworked terrigenous sand. The Holocene section records drowning due to recent (approximately 6 Ka) transgression of the older, lowstand distributary sands on the northern Belize shelf. This mixed carbonate-siliciclastic section and the worm reefs presently are being reshaped and modified by littoral processes.

  2. Multiple outer-reef tracts along the south Florida bank margin: Outlier reefs, a new windward-margin model

    SciTech Connect

    Lidz, B.H.; Shinn, E.A.; Kindinger, J.L. ); Hine, A.C. )

    1991-02-01

    High-resolution seismic-reflection profiles off the lower Florida Keys reveal a multiple outlier-reef tract system {approximately}0.5 to 1.5 km seaward of the bank margin. The system is characterized by a massive, outer main reef tract of high (28 m) unburied relief that parallels the margin and at least two narrower, discontinuous reef tracts of lower relief between the main tract and the shallow bank-margin reefs. The outer tract is {approximately}0.5 to 1 km wide and extends a distance of {approximately}57 km. A single pass divides the outer tract into two main reefs. The outlier reefs developed an antecedent, low-gradient to horizontal offbank surfaces, interpreted to be Pleistocene beaches that formed terracelike features. Radiocarbon dates of a coral core from the outer tract confirm a pre-Holocene age. These multiple outlier reefs represent a new windward-margin model that presents a significant, unique mechanism for progradation of carbonate platforms during periods of sea-level fluctuation. Infilling of the back-reef terrace basins would create new terraced promontories and would extend or step the platform seaward for hundreds of meters. Subsequent outlier-reef development would produce laterally accumulating sequences.

  3. Exploring Drowned Reefs on Gardner Pinnacles

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Gardner Pinnacles (GP), located in the Northwest Hawaiian Islands within Papahānaumokuākea Marine National Monument, is one of the largest volcanic structures in the entire Hawaiian-Emperor chain. In Oct. 2011, the R/V Ka'imikai-o-Kanaloa mapped and the Pisces IV submersible explored the GP during 7 dives, mainly on drowned reef terraces. New multibeam bathymetric data from the cruise, combined with pre-existing multibeam data mostly collected during transits across the structure, show at least 4 separate volcanoes partially surrounded by several Miocene to Pleistocene drowned coral reefs with extensive lagoons, with the largest volcano surmounted by an active carbonate platform. Large landslides modify the flanks, and the eastern flank is incised by submarine canyons. Seven submersible dives explored and sampled mainly the drowned reef structures. The largest reef complex is on the NW flank above the main break-in-slope, and is a barrier reef surrounding extensive lagoon deposits with complex channel structures. Similar wide lagoons with deep channels parallel to the outer reef terraces are present elsewhere on GP, but unusual elsewhere in the Hawaiian Islands. Seven corals, coralline algae, and echinoid spines from dive P4-266 on that NW edge of GP from 1268-1637 m depth yield a tight age cluster based on Sr-isotopes calibrated to seawater that range from 15.51 to 15.98 Ma, and average 15.76 Ma. Five ages of echinoid spines, mollusk shells, and large foraminfers from dive P4-255 on the SW edge of GP from 1538-1558 m depth range from 14.88 to 15.10 Ma, and average 14.98 Ma. Three ages of corals and coralline algae from dive P4-253 on the SE edge of GP at 1955 m depth range from 12.35 and 12.7 Ma, and average 12.57 Ma. The ages of these reefs indicate when volcanic activity waned and reef deposits could accumulate without constant burial by lava flows; the nearly 3.2 Ma range in reef ages from the flanks of GP suggest that volcanic activity at GP spanned a

  4. Scopolamine Transdermal Patch

    MedlinePlus

    ... patch from its protective pouch. To expose the adhesive surface of the patch, the clear plastic protective ... peeled off and discarded. Contact with the exposed adhesive layer should be avoided to prevent contamination of ...

  5. SafePatch

    SciTech Connect

    Kelley, M.; Elko, S.

    2000-10-01

    Authenticating and upgrading system software plays a critical role in information security, yet practical tools for assessing and installing software are lacking in today's marketplace. The SafePatch tool provides the mechanism of performing automated analysis, notification, distribution, and installation of security patches and related software to network-based computer systems in a vendor-independent fashion. SafePatch assists in the authentication of software by comparing the system's objects with the patch's objects. SafePatch will monitor vendor's sites to determine when new patches are released and will upgrade system software on target systems automatically. This paper describes the design of SafePatch, motivations behind the project and the advantages of SafePatch over existing tools.

  6. Metal Patch Antenna

    NASA Technical Reports Server (NTRS)

    Chamberlain, Neil F. (Inventor); Hodges, Richard E. (Inventor); Zawadzki, Mark S. (Inventor)

    2012-01-01

    Disclosed herein is a patch antenna comprises a planar conductive patch attached to a ground plane by a support member, and a probe connector in electrical communication with the conductive patch arranged to conduct electromagnetic energy to or from the conductive patch, wherein the conductive patch is disposed essentially parallel to the ground plane and is separated from the ground plane by a spacing distance; wherein the support member comprises a plurality of sides disposed about a central axis oriented perpendicular to the conductive patch and the ground plane; wherein the conductive patch is solely supported above the ground plane by the support member; and wherein the support member provides electrical communication between the planer conductive patch and the ground plane.

  7. Birth Control Patch

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Birth Control Patch KidsHealth > For Teens > Birth Control Patch A A A What's in this article? ... Much Does It Cost? What Is It? The birth control patch is a thin, beige, 1¾-inch (4½- ...

  8. Birth Control Patch

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Birth Control Patch KidsHealth > For Teens > Birth Control Patch Print A A A What's in this ... Much Does It Cost? What Is It? The birth control patch is a thin, beige, 1¾-inch (4½- ...

  9. Geohydrology of Enewetak Atoll islands and reefs

    SciTech Connect

    Buddemeier, R.W.

    1981-05-06

    Extensive tidal studies in island wells and the lagoon at Enewetak Atoll have shown that island ground water dynamics are controlled by a layered aquifer system. The surface aquifer of unconsolidated Holocene material extends to a depth of approximately 15 m, and has a hydraulic conductivity K = 60 m/day. From 15 to 60 m (approximate lagoon depth) the reef structure consists of successive layers of altered Pleistocene materials, with bulk permeability substantially higher than that of the surface aquifer. Because of wave set-up over the windward reef and the limited pass area for outflow at the south end of the atoll, lagoon tides rise in phase with the ocean tides but fall later than the ocean water level. This results in a net lagoon-to-ocean head which can act as the driving force for outflow through the permeable Pleistocene aquifer. This model suggests that fresh water, nutrients or radioactive contaminants found in island ground water or reef interstitial water may be discharged primarily into the ocean rather than the lagoon. Atoll island fresh water resources are controlled by recharge, seawater dilution due to vertical tidal mixing between the surface and deeper aquifers, and by loss due to entrainment by the outflowing water in the deeper aquifers. Estimated lagoon-ot-ocean transit times through the deep aquifer are on the order of a few years, which corresponds well to the freshwater residence time estimates based on inventory and recharge. Islands in close proximity to reef channels have more fresh ground water than others, which is consistent with a locally reduced hydraulic gradient and slower flow through the Pleistocene aquifers.

  10. Late Quaternary structure and development of the northern Ningaloo Reef, Australia

    NASA Astrophysics Data System (ADS)

    Collins, Lindsay B.; Zhu, Zhong Rong; Wyrwoll, Karl-Heinz; Eisenhauer, Anton

    2003-06-01

    Ningaloo Reef, situated on the central west coast, is Australia's largest fringing reef system extending southward from 22°S for over 200 km. Its narrow lagoon is backed by a coastal plain, which is largely composed of an emergent Last Interglacial reef on the flank of folded Tertiary limestones. The west-facing reef is exposed to strong oceanic swells across a narrow (8 km) continental shelf. Climatic aridity, cyclones, tsunamis, and the poleward flowing Leeuwin Current all influence the reef system. Seismic profiling and a coring and dating program along a transect through a reef pass indicate two periods of reef development in the northern part of the reef: Holocene and Last Interglacial. Seaward of the crest, the Holocene reef forms either a prominent 500 m-wide bulge with 10 m of relief and an abrupt seaward slope, or a series of discrete patch reefs. Holocene reef development is limited to depths of less than 30 m and reaches a maximum thickness of ca. 10-15 m below the reef crest. U/Th TIMS dates from distal parts of the Last Interglacial section between -18 and -36 m give ages toward the end of the high stand (120-115 ka). Last Interglacial reef growth was more extensive of the two, filling much of the available accommodation space, perhaps as a result of a stronger Leeuwin Current. This substrate subsequently provided an antecedent foundation for Holocene reef development.

  11. Predators reduce abundance and species richness of coral reef fish recruits via non-selective predation

    NASA Astrophysics Data System (ADS)

    Heinlein, J. M.; Stier, A. C.; Steele, M. A.

    2010-06-01

    Predators have important effects on coral reef fish populations, but their effects on community structure have only recently been investigated and are not yet well understood. Here, the effect of predation on the diversity and abundance of young coral reef fishes was experimentally examined in Moorea, French Polynesia. Effects of predators were quantified by monitoring recruitment of fishes onto standardized patch reefs in predator-exclosure cages or uncaged reefs. At the end of the 54-day experiment, recruits were 74% less abundant on reefs exposed to predators than on caged ones, and species richness was 42% lower on reefs exposed to predators. Effects of predators varied somewhat among families, however, rarefaction analysis indicated that predators foraged non-selectively among species. These results indicate that predation can alter diversity of reef fish communities by indiscriminately reducing the abundance of fishes soon after settlement, thereby reducing the number of species present on reefs.

  12. Behavioural and developmental responses of predatory coral reef fish to variation in the abundance of prey

    NASA Astrophysics Data System (ADS)

    Beukers-Stewart, B. D.; Beukers-Stewart, J. S.; Jones, G. P.

    2011-09-01

    Ecological theory suggests that the behaviour, growth and abundance of predators will be strongly influenced by the abundance of prey. Predators may in turn play an important role in structuring prey populations and communities. Responses of predators to variation in prey abundance have most commonly been demonstrated in low-diversity communities where food webs are relatively simple. How predators respond in highly diverse assemblages such as in coral reef habitats is largely unknown. This study describes an experiment that examined how the movement, diet and growth of the coral reef piscivore, Cephalopholis boenak (Serranidae) responded to variation in the abundance of its prey. Predator densities were standardised on small patch reefs made from the lagoonal reef-building coral, Porites cylindrica. These patch reefs exhibited natural variation in the abundance and community structure of multiple species of prey. However, our experiment generated a relatively simple predator-prey relationship, with C. boenak primarily responding to the most abundant species of prey. Three responses of predators were observed: aggregative, functional and developmental. Thirty-one per cent of individuals moved between patch reefs during the experiment, all from areas of relatively low to high prey density. Feeding rates were higher on patch reefs of high prey density, while growth rates of fish that remained on low prey density reefs throughout the experiment were lower. Growth rates of C. boenak on the experimental reefs were also much higher than for those living on natural patch reefs over the same time period, corresponding with overall differences in prey abundance. These results suggest that local abundance, feeding rate and growth of C. boenak were closely linked to the abundance of their main prey. This combination of predatory responses is a potential mechanism behind recent observations of density-dependent mortality and population regulation of prey in coral reef fish

  13. Reef productivity and preservation during the Late Neogene

    NASA Astrophysics Data System (ADS)

    Husson, Laurent; Pastier, Anne-Morwenn; Schmitt, Anais; Sarr, Anta-Clarisse; Elliot, Mary; Pedoja, Kevin; Bezos, Antoine

    2016-04-01

    During the glacial-interglacials cycles that prevailed during Plio-Pleistocence times, the pace of sea level oscillations exerts a major control on coral reef growth and expansion. We designed a numerical model to quantify reef productivity and carbonate preservation that accounts for sea level oscillations, reef growth, erosion and subsequent geomorphological carving. We carried out a parametric study of a variety of processes (reef growth, erosion, local slope, uplift and subsidence, relative sea level, etc) towards a probabilistic analysis of reef productivity and carbonate production. We further test the effect of the frequency and amplitude of sea level oscillations using sea level curves derived from both the 18O isotope record of past sea level change and synthetic sinusoidal sea level curves. Over a typical climate cycle, our model simulations confirm that the rate of sea level change is the primary controlling factor of reef production, as it modifies the productivity by several orders of magnitude. Most importantly, reef productivity increases during periods of sea level rise, and decreases during sea level stands, while conversely, the morphology records the opposite in a misleading fashion: Reef terraces expand during sea level stands due to the joint effects of erosion and patient reef growth at a stationary level until the accommodation space is filled up. On the long-term, over the Plio-Pleistocene period, vertical ground motion also significantly alters the production: moderate uplift or subsidence can boost reef productivity up to tenfold with respect to a stationary coastline. Last, the amplitude and frequency of the sea level oscillations (typically 40 kyrs vs. 100 kyrs periods) moderately impact reef productivity. These results can be ultimately converted into estimates of carbonate production and carbon sequestration during the Late Neogene, provided relative sea level is documented in the tectonically agitated intertropical zone.

  14. The 1991 1992 rapid ecological assessment of Palau's coral reefs

    NASA Astrophysics Data System (ADS)

    Maragos, J. E.; Cook, C. W.

    1995-11-01

    At the request of the Palau and US governments, a team of 30 scientists under the leadership of the Nature Conservancy completed a rapid ecological assessment (REA) of nearshore marine resources in Palau in 1992. The REA provided ecological input to Palau's ongoing master plan for economic development and identified 45 marine sites worthy of special protection. The REA relied on previous literature, 1992 aerial photography, interviews, and field observations. A combination of qualitative and quantitative techniques were used to assess stony corals, other reef invertebrates, reef and shore fishes, macroscopic algae, seagrasses, sea turtles and other marine organisms. The REA covered a variety of coral reef habitats including beaches, seagrass beds, fringing reefs, lagoons, passes, channels, reef holes, patch and pinnacle reefs, barrier reefs, atolls, submerged reefs, mangroves, and "rock" islands. Major stresses to Palau's coral reefs include sedimentation from soil erosion, overfishing, and damage from periodic storms and waves. Minor stresses include dredge-and fill activities, sewage pollution, anchor damage, tourism use, ship groundings, aquarium fish collecting, and minor crown-of-thorns ( Acanthaster) infestations.

  15. A multiscale analysis of coral reef topographic complexity using lidar-derived bathymetry

    USGS Publications Warehouse

    Zawada, D.G.; Brock, J.C.

    2009-01-01

    Coral reefs represent one of the most irregular substrates in the marine environment. This roughness or topographic complexity is an important structural characteristic of reef habitats that affects a number of ecological and environmental attributes, including species diversity and water circulation. Little is known about the range of topographic complexity exhibited within a reef or between different reef systems. The objective of this study was to quantify topographic complexity for a 5-km x 5-km reefscape along the northern Florida Keys reef tract, over spatial scales ranging from meters to hundreds of meters. The underlying dataset was a 1-m spatial resolution, digital elevation model constructed from lidar measurements. Topographic complexity was quantified using a fractal algorithm, which provided a multi-scale characterization of reef roughness. The computed fractal dimensions (D) are a measure of substrate irregularity and are bounded between values of 2 and 3. Spatial patterns in D were positively correlated with known reef zonation in the area. Landward regions of the study site contain relatively smooth (D ??? 2.35) flat-topped patch reefs, which give way to rougher (D ??? 2.5), deep, knoll-shaped patch reefs. The seaward boundary contains a mixture of substrate features, including discontinuous shelf-edge reefs, and exhibits a corresponding range of roughness values (2.28 ??? D ??? 2.61). ?? 2009 Coastal Education and Research Foundation.

  16. Climate-driven coral reorganisation influences aggressive behaviour in juvenile coral-reef fishes

    NASA Astrophysics Data System (ADS)

    Kok, Judith E.; Graham, Nicholas A. J.; Hoogenboom, Mia O.

    2016-06-01

    Globally, habitat degradation is altering the abundance and diversity of species in a variety of ecosystems. This study aimed to determine how habitat degradation, in terms of changing coral composition under climate change, affected abundance, species richness and aggressive behaviour of juveniles of three damselfishes ( Pomacentrus moluccensis, P. amboinensis and Dischistodus perspicillatus, in order of decreasing reliance on coral). Patch reefs were constructed to simulate two types of reefs: present-day reefs that are vulnerable to climate-induced coral bleaching, and reefs with more bleaching-robust coral taxa, thereby simulating the likely future of coral reefs under a warming climate. Fish communities were allowed to establish naturally on the reefs during the summer recruitment period. Climate-robust reefs had lower total species richness of coral-reef fishes than climate-vulnerable reefs, but total fish abundance was not significantly different between reef types (pooled across all species and life-history stages). The nature of aggressive interactions, measured as the number of aggressive chases, varied according to coral composition; on climate-robust reefs, juveniles used the substratum less often to avoid aggression from competitors, and interspecific aggression became relatively more frequent than intraspecific aggression for juveniles of the coral-obligate P. moluccensis. This study highlights the importance of coral composition as a determinant of behaviour and diversity of coral-reef fishes.

  17. Llandoverian to Ludlovian barrier reef complex in southeast Wisconsin

    SciTech Connect

    Rovey, C.W. )

    1989-08-01

    Subsurface exploration in the Michigan basin established that a carbonate bank and barrier reef complex prograded basinward during the late Wenlockian to early Ludlovian, but the corresponding Niagaran Series is generally undifferentiated. In southeast Wisconsin the series is well exposed; thus, a better record of depositional history is available. Until now, reefs in the Racine formation of southeast Wisconsin (upper Wenlockian through lower Ludlovian) were interpreted as patch reefs built landward of the barrier complex. However, the following criteria are consistent with an extension of Michigan's northern barrier complex beneath Lake Michigan to southeast Wisconsin: (1) Ubiquitous presence of reef facies along a southwest to northeast trend. This trend is coincident with thickening and a facies change indicative of a deep to shallow water transition, (2) similarity in depositional sequence of the overlying Salina Group in Wisconsin and Michigan. The Salina sediments surround, but are absent over, structures interpreted as pinnacle reefs and form a feather edge against the thicker belt interpreted as a barrier complex. Hence, the Racine reefs are reinterpreted as a barrier complex. Hence, the Racine reefs are reinterpreted as a barrier and pinnacle reef complex. Similar facies changes are also present in older formations. Intraformational truncation surfaces in the underlying Waukesha Dolomite (upper Llandoverian to lower Wenlockian) clearly indicate the presence of a nearby carbonate slope. Therefore, the carbonate buildup originated prior to the Wenlockian and migrated further basinward than previously believed.

  18. Porosity evolution of upper Miocene reefs, Almeria Province, southern Spain

    USGS Publications Warehouse

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

    1980-01-01

    Sea cliffs 40 km east of Almeria, southeastern Spain, expose upper Miocene reefs and patch reefs of the Plomo formation. These reefs are formed of scleractinian corals, calcareous algae, and mollusks. The reef cores are as much as 65 m thick and several hundred meters wide. Fore-reef talus beds extend 1,300 m across and are 40 m thick. The reefs and reef breccias are composed of calcific dolomite. They lie on volcanic rocks that have a K-Ar date of 11.5 m.y. and in turn are overlain by the upper Miocene Vicar Formation. In the reef cores and fore-reef breccia beds, porosity is both primary and postdepositional. Primary porosity is of three types: (a) boring clam holes in the scleractinian coral heads, cemented reef rocks, and breccias; (b) intraparticle porosity within the corals, Halimeda plates, and vermetid worm tubes; and (c) interparticle porosity between bioclastic fragments and in the reef breccia. Postdepositional moldic porosity was formed by the solution of aragonitic material such as molluscan and coral fragments. The Plomo reef carbonate rocks have high porosity and permeability, and retain a great amount of depositional porosity. Pores range in size from a few micrometers to 30 cm. The extensive intercrystalline porosity and high permeability resulted from dolomitization of micritic matrix. Dolomite rhombs are between 10 and 30 μ across. More moldic porosity was formed by the dissolution of the calclte bioclasts. Some porosity reduction has occurred by incomplete and partial sparry calcite infilling of interparticular, moldic, and intercrystalline voids. The high porosity and permeability of these reefs make them important targets for petroleum exploration in the western Mediterranean off southern Spain. In these offshore areas in the subsurface the volcanic ridge and the Plomo reef complex are locally onlapped or overlapped by 350 m or more of Miocene(?) and Pliocene fine-grained sedimentary rocks. The possibility exists that the buried Plomo reef

  19. Coral Reefs at the Northernmost Tip of Borneo: An Assessment of Scleractinian Species Richness Patterns and Benthic Reef Assemblages

    PubMed Central

    Waheed, Zarinah; van Mil, Harald G. J.; Syed Hussein, Muhammad Ali; Jumin, Robecca; Golam Ahad, Bobita; Hoeksema, Bert W.

    2015-01-01

    The coral reefs at the northernmost tip of Sabah, Borneo will be established under a marine protected area: the Tun Mustapha Park (TMP) by the end of 2015. This area is a passage where the Sulu Sea meets the South China Sea and it is situated at the border of the area of maximum marine biodiversity, the Coral Triangle. The TMP includes fringing and patch reefs established on a relatively shallow sea floor. Surveys were carried out to examine features of the coral reefs in terms of scleractinian species richness, and benthic reef assemblages following the Reef Check substrate categories, with emphasis on hard coral cover. Variation in scleractinian diversity was based on the species composition of coral families Fungiidae (n = 39), Agariciidae (n = 30) and Euphylliidae (n = 15). The number of coral species was highest at reefs with a larger depth gradient i.e. at the periphery of the study area and in the deep South Banggi Channel. Average live hard coral cover across the sites was 49%. Only 7% of the examined reefs had > 75% hard coral cover, while the majority of the reef sites were rated fair (51%) and good (38%). Sites with low coral cover and high rubble fragments are evidence of blast fishing, although the observed damage appeared old. Depth was a dominant factor in influencing the coral species composition and benthic reef communities in the TMP. Besides filling in the information gaps regarding species richness and benthic cover for reef areas that were previously without any data, the results of this study together with information that is already available on the coral reefs of TMP will be used to make informed decisions on zoning plans for conservation priorities in the proposed park. PMID:26719987

  20. Coral Reefs at the Northernmost Tip of Borneo: An Assessment of Scleractinian Species Richness Patterns and Benthic Reef Assemblages.

    PubMed

    Waheed, Zarinah; van Mil, Harald G J; Syed Hussein, Muhammad Ali; Jumin, Robecca; Golam Ahad, Bobita; Hoeksema, Bert W

    2015-01-01

    The coral reefs at the northernmost tip of Sabah, Borneo will be established under a marine protected area: the Tun Mustapha Park (TMP) by the end of 2015. This area is a passage where the Sulu Sea meets the South China Sea and it is situated at the border of the area of maximum marine biodiversity, the Coral Triangle. The TMP includes fringing and patch reefs established on a relatively shallow sea floor. Surveys were carried out to examine features of the coral reefs in terms of scleractinian species richness, and benthic reef assemblages following the Reef Check substrate categories, with emphasis on hard coral cover. Variation in scleractinian diversity was based on the species composition of coral families Fungiidae (n = 39), Agariciidae (n = 30) and Euphylliidae (n = 15). The number of coral species was highest at reefs with a larger depth gradient i.e. at the periphery of the study area and in the deep South Banggi Channel. Average live hard coral cover across the sites was 49%. Only 7% of the examined reefs had > 75% hard coral cover, while the majority of the reef sites were rated fair (51%) and good (38%). Sites with low coral cover and high rubble fragments are evidence of blast fishing, although the observed damage appeared old. Depth was a dominant factor in influencing the coral species composition and benthic reef communities in the TMP. Besides filling in the information gaps regarding species richness and benthic cover for reef areas that were previously without any data, the results of this study together with information that is already available on the coral reefs of TMP will be used to make informed decisions on zoning plans for conservation priorities in the proposed park.

  1. Lidocaine Transdermal Patch

    MedlinePlus

    Lidocaine patches are used to relieve the pain of post-herpetic neuralgia (PHN; the burning, stabbing pains, ... for months or years after a shingles infection). Lidocaine is in a class of medications called local ...

  2. DyninstAPI Patches

    SciTech Connect

    LeGendre, M.

    2012-04-01

    We are seeking a code review of patches against DyninstAPI 8.0. DyninstAPI is an open source binary instrumentation library from the University of Wisconsin and University of Maryland. Our patches port DyninstAPI to the BlueGene/P and BlueGene/Q systems, as well as fix DyninstAPI bugs and implement minor new features in DyninstAPI.

  3. Punctuated Stratigraphic Appearance of Cold-Water Coral Reefs

    NASA Astrophysics Data System (ADS)

    Eberli, G. P.; Correa, T.; Massaferro, J. L.

    2008-05-01

    Existing and new data acquired with an AUV document a high abundance of cold-water coral mounds in the bottom of the Straits of Florida (SoF). These mounds display a large variability of shapes and heights. The abundance and variability encountered in these and modern cold-water coral mounds elsewhere is in stark contrast to lack of reported ancient cold-water coral reefs. Furthermore, the stratigraphic distribution suggests that cold-water corals punctuate the stratigraphic record with times of bloom and times of near complete absence. In the Florida Bahamas region, for example, the stratigraphic distribution is non-uniform. Preliminary age dating of the modern coral mounds produce ages of a few hundred to 1300 years for corals at the surface of the mounds. Sub-bottom profiles and seismic data across the investigated mound fields reveal that the "modern" mounds root in Pleistocene strata but are absent in the Pliocene strata below. Cores taken during ODP Legs 101 and 166 in the SoF confirm the punctuated appearance as deep-water coral rubble was penetrated only in the Pleistocene and in the upper Oligocene strata. The vast occurrence of Oligocene cold-water coral mounds is also visible on a 2-D seismic line in the northern SoF and on a 3-D seismic survey in the southwestern portion of the SoF. In this latter data set a mid-Miocene and the base of Tertiary seismic horizon also image mounded features. These spikes in reef development indicate that environmental conditions were only occasionally favorable for reef growth. The punctuated appearance is surprising as the core and seismic data document continuous current activity since the late Miocene in the SoF. We speculate that the "modern" bloom of cold-water coral reefs in the Pleistocene coincides with the onset of the large barrier reef systems in the Australia and Belize.

  4. Journey to the Reef

    ERIC Educational Resources Information Center

    Bryson, Linda

    2010-01-01

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

  5. Reefs happen

    USGS Publications Warehouse

    Kinzie, R. A.; Buddemeier, R.W.

    1996-01-01

    Corals and coral reefs confront us with a variety of paradoxes in terms of their responses to global change. The species appear evolutionarily long-lived and stable, and combinations of organisms recur and persist at levels ranging from endosymbiosis to palaeocommunity structure. The fact that these organisms and communities occupy a seemingly precarious environment near the common interface of land, sea, and air suggests that they possess powerful adaptive and acclimative mechanisms, and the special characteristics associated with their range of reproductive options, their modular (colonial) form, and their symbiotic associations provide multiple pathways for adaptation. At the same time, they are widely considered to be vulnerable to anthropogenic stresses, and to show signs of deterioration on a global scale. Interest in corals is further enhanced by their unique position with regard to the carbon cycle, with inorganic and organic carbon metabolisms that are of comparable magnitudes. The durable limestone structures they create modify the shallow-water environment, and their mineral skeletons preserve in their isotopic, chemical, and structural characteristics records of past environmental conditions. Whether as survivors, recorders, or victims, their relationship to global change is fascinating and instructive. This paper provides a general background and context for the specific papers that make up this topical issue of Global Change Biology. ?? 1996 Blackwell Science Ltd.

  6. Simulating reef response to sea-level rise at Lizard Island: A geospatial approach

    NASA Astrophysics Data System (ADS)

    Hamylton, S. M.; Leon, J. X.; Saunders, M. I.; Woodroffe, C. D.

    2014-10-01

    Sea-level rise will result in changes in water depth over coral reefs, which will influence reef platform growth as a result of carbonate production and accretion. This study simulates the pattern of reef response on the reefs around Lizard Island in the northern Great Barrier Reef. Two sea-level rise scenarios are considered to capture the range of likely projections: 0.5 m and 1.2 m above 1990 levels by 2100. Reef topography has been established through extensive bathymetric profiling, together with available data, including LiDAR, single beam bathymetry, multibeam swath bathymetry, LADS and digitised chart data. The reef benthic cover around Lizard Island has been classified using a high resolution WorldView-2 satellite image, which is calibrated and validated against a ground referencing dataset of 364 underwater video records of the reef benthic character. Accretion rates are parameterised using published hydrochemical measurements taken in-situ and rules are applied using Boolean logic to incorporate geomorphological transitions associated with different depth ranges, such as recolonisation of the reef flat when it becomes inundated as sea level rises. Simulations indicate a variable platform response to the different sea-level rise scenarios. For the 0.5 m rise, the shallower reef flats are gradually colonised by corals, enabling this active geomorphological zone to keep up with the lower rate of rise while the other sand dominated areas get progressively deeper. In the 1.2 m scenario, a similar pattern is evident for the first 30 years of rise, beyond which the whole reef platform begins to slowly drown. To provide insight on reef response to sea-level rise in other areas, simulation results of four different reef settings are discussed and compared at the southeast reef flat (barrier reef), Coconut Beach (fringing reef), Watson's Bay (leeward bay with coral patches) and Mangrove Beach (sheltered lagoonal embayment). The reef sites appear to accrete upwards

  7. Newly discovered reefs in the southern Abrolhos Bank, Brazil: Anthropogenic impacts and urgent conservation needs.

    PubMed

    Mazzei, E F; Bertoncini, A A; Pinheiro, H T; Machado, L F; Vilar, C C; Guabiroba, H C; Costa, T J F; Bueno, L S; Santos, L N; Francini-Filho, R B; Hostim-Silva, M; Joyeux, J-C

    2017-01-15

    The Abrolhos Bank is an area of high ecological, socio-economic importance and harbour the richest and most-extensive coral reefs in the South Atlantic. Here we report the discovery of shallow (12-25m depth) reef complex with ten large biogenic structures, intermediate between the typical mushroom-shaped pinnacles of the northern Abrolhos Bank (17°-18° S) and the small patch reefs found on the central/southern coast of the Espírito Santo State (19°-20° S). The newly discovered reefs harbour a relatively rich and abundant reef community, with 73 fish and 14 benthic cnidarian species, including endangered and commercially important ones. We discuss on urgent needs of properly mapping and understanding the ecological functioning of this reef system. Information provided here is a baseline for future impact evaluations, particularly considering the recent worst environmental disaster of Brazil from a dam collapse in Doce river that affected the region.

  8. Sperm Patch-Clamp

    PubMed Central

    Lishko, Polina; Clapham, David E.; Navarro, Betsy; Kirichok, Yuriy

    2014-01-01

    Sperm intracellular pH and calcium concentration ([Ca2+]i) are two central factors that control sperm activity within the female reproductive tract. As such, the ion channels of the sperm plasma membrane that alter intracellular sperm [Ca2+] and pH play important roles in sperm physiology and the process of fertilization. Indeed, sperm ion channels regulate sperm motility, control sperm chemotaxis toward the egg in some species, and may trigger the acrosome reaction. Until recently, our understanding of these important molecules was rudimentary due to the inability to patch-clamp spermatozoa and directly record the activity of these ion channels under voltage clamp. Recently, we overcame this technical barrier and developed a method for reproducible application of the patch-clamp technique to mouse and human spermatozoa. This chapter covers important aspects of application of the patch-clamp technique to spermatozoa, such as selection of the electrophysiological equipment, isolation of spermatozoa for patch-clamp experiments, formation of the gigaohm seal with spermatozoa, and transition into the whole-cell mode of recording. We also discuss potential pitfalls in application of the patch-clamp technique to flagellar ion channels. PMID:23522465

  9. Kenyan coral reef-associated gastropod assemblages: distribution and diversity patterns

    NASA Astrophysics Data System (ADS)

    McClanahan, T. R.

    1990-09-01

    A survey of Kenya's shallow water (<2 m) coral reef-associated prosobranch fauna was undertaken to determine patterns of distribution, density, diversity and species richness, and the possible role of other reef fauna and human utilization on these patterns. The sample assemblage of 135 species from 25 families is similar to other Indian Ocean regions with no apparent endemism or subregional faunal affinities. Species richness, determined by species-individual relationships, has been reduced by approximately 45% since the Pleistocene. Northern Kenya, typified by small coral islands experiencing river and estuarine discharges had low densities and species richness and high species variability. This is attributable to the interrelated factors of river discharge, small reefs and reduced predator refuge. Southern Kenya's more expansive fringing reef has a denser and richer fauna but appears less species rich than Tanzania. Variation within reefs suggests similarities in diversity between reef lagoons, flats and edges, but lagoons had lower densities than reef flat or edge sites. This is attributable to greater predation rates within lagoons. Species composition between reef locations was variable but differed for comparisons between reef lagoons and reef flats. The population densities of thirty commercially collected species were compared between shelled and unshelled reefs. Only two commercial strombids, Lambis truncata and L. chiragra, had lower densities within shelled compared to unshelled reefs. Within six southern Kenvan reef lagoons, total gastropod densities were negatively correlated with the Balistidae (triggerfish) and total fish densities and positively with sea urchin densities. The removal of balistids through fishing appears to lead to co-occurring population increases in gastropod and sea urchin populations which, in most instances, appears to negate the effect of shell collecting.

  10. Status and conservation of coral reefs in Costa Rica.

    PubMed

    Cortés, Jorge; Jiménez, Carlos E; Fonseca, Ana C; Alvarado, Juan José

    2010-05-01

    Costa Rica has coral communities and reefs on the Caribbean coast and on the Pacific along the coast and off-shore islands. The Southern section of the Caribbean coast has fringing and patch reefs, carbonate banks, and an incipient algal ridge. The Pacific coast has coral communities, reefs and isolated coral colonies. Coral reefs have been seriously impacted in the last 30 years, mainly by sediments (Caribbean coast and some Pacific reefs) and by El Niño warming events (both coasts). Monitoring is being carried out at three sites on each coast. Both coasts suffered significant reductions in live coral cover in the 1980's, but coral cover is now increasing in most sites. The government of Costa Rica is aware of the importance of coral reefs and marine environments in general, and in recent years decrees have been implemented (or are in the process of approval) to protect them, but limited resources endanger their proper management and conservation, including proper outreach to reef users and the general public.

  11. Predation and landscape characteristics independently affect reef fish community organization.

    PubMed

    Stier, Adrian C; Hanson, Katharine M; Holbrook, Sally J; Schmitt, Russell J; Brooks, Andrew J

    2014-05-01

    Trophic island biogeography theory predicts that the effects of predators on prey diversity are context dependent in heterogeneous landscapes. Specifically, models predict that the positive effect of habitat area on prey diversity should decline in the presence of predators, and that predators should modify the partitioning of alpha and beta diversity across patchy landscapes. However, experimental tests of the predicted context dependency in top-down control remain limited. Using a factorial field experiment we quantify the effects of a focal predatory fish species (grouper) and habitat characteristics (patch size, fragmentation) on the partitioning of diversity and assembly of coral reef fish communities. We found independent effects of groupers and patch characteristics on prey communities. Groupers reduced prey abundance by 50% and gamma diversity by 45%, with a disproportionate removal of rare species relative to common species (64% and 36% reduction, respectively; an oddity effect). Further, there was a 77% reduction in beta diversity. Null model analysis demonstrated that groupers increased the importance of stochastic community assembly relative to patches without groupers. With regard to patch size, larger patches contained more fishes, but a doubling of patch size led to a modest (36%) increase in prey abundance. Patch size had no effect on prey diversity; however, fragmented patches had 50% higher species richness and modified species composition relative to unfragmented patches. Our findings suggest two different pathways (i.e., habitat or predator shifts) by which natural and/or anthropogenic processes can drive variation in fish biodiversity and community assembly.

  12. Fine-scale environmental specialization of reef-building corals might be limiting reef recovery in the Florida Keys.

    PubMed

    Kenkel, Carly D; Almanza, Albert T; Matz, Mikhail V

    2015-12-01

    Despite decades of monitoring global reef decline, we are still largely unable to explain patterns of reef deterioration at local scales, which precludes the development of effective management strategies. Offshore reefs of the Florida Keys, USA, experience milder temperatures and lower nutrient loads in comparison to inshore reefs yet remain considerably more degraded than nearshore patch reefs. A year-long reciprocal transplant experiment of the mustard hill coral (Porites astreoides) involving four source and eight transplant locations reveals that corals adapt and/or acclimatize to their local habitat on a < 10-km scale. Surprisingly, transplantation to putatively similar environmental types (e.g., offshore corals moved to a novel offshore site, or along-shore transplantation) resulted in greater reductions in fitness proxies, such as coral growth, than cross-channel transplantation between inshore and offshore reefs. The only abiotic factor showing significantly greater differences between along-shore sites was daily temperature range extremes (rather than the absolute high or low temperatures reached), providing a possible explanation for this pattern. Offshore-origin corals exhibited significant growth reductions at sites with greater daily temperature ranges, which explained up to 39% of the variation in their mass gain. In contrast, daily temperature range explained at most 9% of growth variation in inshore-origin corals, suggesting that inshore corals are more tolerant of high-frequency temperature fluctuations. Finally, corals incur trade-offs when specializing to their native reef. Across reef locations the coefficient of selection against coral transplants was 0.07 ± 0.02 (mean ± SE). This selection against immigrants could hinder the ability of corals to recolonize devastated reefs, whether through assisted migration efforts or natural recruitment events, providing a unifying explanation for observed patterns of coral decline in this reef system.

  13. Coral communities of the remote atoll reefs in the Nansha Islands, southern South China Sea.

    PubMed

    Zhao, M X; Yu, K F; Shi, Q; Chen, T R; Zhang, H L; Chen, T G

    2013-09-01

    During the months of May and June in the year 2007, a survey was conducted regarding coral reef communities in the remote atolls (Zhubi Reef and Meiji Reef) of Nansha Islands, southern South China Sea. The goals of the survey were to: (1) for the first time, compile a scleractinian coral check-list; (2) estimate the total richness, coral cover, and growth forms of the community; and (3) describe preliminary patterns of community structure according to geomorphological units. Findings of this survey revealed a total of 120 species of scleractinia belonging to 40 genera, while the average coral cover was 21 %, ranging from less than 10 % to higher than 50 %. Branching and massive corals were also found to be the most important growth forms of the whole coral community, while Acropora, Montipora, and Porites were the three dominant genera in the overall region, with their contributions to total coral cover measuring 21, 22, and 23 %, respectively. Overall, coral communities of the Nansha Islands were in a relative healthy condition with high species diversity and coral cover. Spatial pattern of coral communities existed among various geomorphological units. Mean coral cover was highest in the patch reef within the lagoon, followed by the fore reef slope, reef flat, and lagoon slope. The greatest contributors to total coral cover were branching Acropora (45 %) in the lagoon slope, branching Montipora (44 %) in the reef flat, and massive Porites (51 %) in the patch reef. Coral cover in the fore reef revealed a greater range of genera than in other habitats. The leeward fore reef slope had higher coral cover (> 50 %) when compared with the windward slope (< 10 %). The coral communities of the inner reef flat were characterized by higher coral cover (27 %) and dominant branching Montipora corals, while lower coral cover (4 %) was dominated by Psammocora with massive growth forms on the outer reef flat. Destructive fishing and coral bleaching were two major threats to

  14. Sedimentology and sequence stratigraphy of upper Pleistocene carbonates of southeastern Barbardos, West Indies

    SciTech Connect

    Humphrey, J.D.; Kimbell, T.N. )

    1990-11-01

    Upper Pleistocene reef-associated carbonates of southeastern Barbados have been studied in outcrop and core. Reef terraces, formed during glacio-eustatic sea level highstands and subsequently uplifted, are characterized by thick and areally extensive sequences of allochthonous and autochthonous fore-reef calcarenites. Depositional textures are primarily packstones, and grainstones, wackestones, and coral floatstones are volumetrically less significant. Sediments are coarse- to fine-grained reef-derived allochems and micrite, and autochthonous benthic foraminifera and coralline red algae. Rates of sediment accumulation of fore-reef calcarenites range from about 1 to 4 m/1,000 yr. Although of relatively small scale, the carbonate terraces of southeastern Barbados provide excellent analogs for sequence stratigraphic concepts in carbonate settings. The terraces are primarily highstand systems tract deposits separated by type 1 unconformities. These highstand deposits are characterized by reef development and the progradation of fore-reef calcarenites. Extensive fore-reef deposits resulted from mechanical erosion of the reef framework on this high-energy, windward coastline. Type 1 unconformities are characterized by thin caliche layers developed during lowstand subaerial exposure. Thin basal transgressive systems tract deposits are characterized by incorporation of extraformational clasts derived from the underlying sequence during sea level rise. Slope-front erosion, vertical shift in the position of freshwater lens, and shift in the position of coastal onlap are all consequences of the interplay between eustasy and tectonics. These effects and the development of facies geometries on Barbados are primarily controlled by the glacio-eustatic component, inasmuch as rates of eustatic changes of sea level are at least two orders of magnitude greater than the maximum average rates of tectonic uplift. 12 figs.

  15. Contrasts within an outlier-reef system: Evidence for differential quaternary evolution, south Florida windward margin, U.S.A.

    USGS Publications Warehouse

    Lidz, B.H.; Shinn, E.A.; Hine, A.C.; Locker, S.D.

    1997-01-01

    Closely spaced, high-resolution, seismic-reflection profiles acquired off the upper Florida Keys (i.e., north) reveal a platform-margin reef-and-trough system grossly similar to, yet quite different from, that previously described off the lower Keys (i.e., south). Profiles and maps generated for both areas show that development was controlled by antecedent Pleistocene topography (presence or absence of an upper-slope bedrock terrace), sediment availability, fluctuating sea level, and coral growth rate and distribution. The north terrace is sediment-covered and exhibits linear, buried, low-relief, seismic features of unknown character and origin. The south terrace is essentially sediment-free and supports multiple, massive, high-relief outlier reefs. Uranium disequilibrium series dates on outlier-reef corals indicate a Pleistocene age (~83-84 ka). A massive Pleistocene reef with both aggradational (north) and progradational (south) aspects forms the modern margin escarpment landward of the terrace. Depending upon interpretation (the north margin-escarpment reef may or may not be an outlier reef), the north margin is either more advanced or less advanced than the south margin. During Holocene sea-level rise, Pleistocene bedrock was inundated earlier and faster first to the north (deeper offbank terrace), then to the south (deeper platform surface). Holocene overgrowth is thick (8 m) on the north outer-bank reefs but thin (0.3 m) on the south outlier reefs. Differential evolution resulted from interplay between fluctuating sea level and energy regime established by prevailing east-southeasterly winds and waves along an arcuate (ENE-WSW) platform margin.

  16. LIDAR optical rugosity of coral reefs in Biscayne National Park, Florida

    USGS Publications Warehouse

    Brock, J.C.; Wright, C.W.; Clayton, T.D.; Nayegandhi, A.

    2004-01-01

    The NASA Experimental Advanced Airborne Research Lidar (EAARL), a temporal waveform-resolving, airborne, green wavelength LIDAR (light detection and ranging), is designed to measure the submeter-scale topography of shallow reef substrates. Topographic variability is a prime component of habitat complexity, an ecological factor that both expresses and controls the abundance and distribution of many reef organisms. Following the acquisition of EAARL coverage over both mid-platform patch reefs and shelf-margin bank reefs within Biscayne National Park in August 2002, EAARL-based optical indices of topographic variability were evaluated at 15 patch reef and bank reef sites. Several sites were selected to match reefs previously evaluated in situ along underwater video and belt transects. The analysis used large populations of submarine topographic transects derived from the examination of closely spaced laser spot reflections along LIDAR raster scans. At all 15 sites, each LIDAR transect was evaluated separately to determine optical rugosity (Rotran), and the average elevation difference between adjacent points (Av(??E ap)). Further, the whole-site mean and maximum values of Ro tran and Av(??Eap) for the entire population of transects at each analysis site, along with their standard deviations, were calculated. This study revealed that the greater habitat complexity of inshore patch reefs versus outer bank reefs results in relative differences in topographic complexity that can be discerned in the laser returns. Accordingly, LIDAR sensing of optical rugosity is proposed as a complementary new technique for the rapid assessment of shallow coral reefs. ?? Springer-Verlag 2004.

  17. Are artificial reefs surrogates of natural habitats for corals and fish in Dubai, United Arab Emirates?

    NASA Astrophysics Data System (ADS)

    Burt, J.; Bartholomew, A.; Usseglio, P.; Bauman, A.; Sale, P. F.

    2009-09-01

    Artificial reefs are often promoted as mitigating human impacts in coastal ecosystems and enhancing fisheries; however, evidence supporting their benefits is equivocal. Such structures must be compared with natural reefs in order to assess their performance, but past comparisons typically examined artificial structures that were too small, or were immature, relative to the natural reefs. We compared coral and fish communities on two large (>400,000 m3) and mature (>25 year) artificial reefs with six natural coral patches. Coral cover was higher on artificial reefs (50%) than in natural habitats (31%), but natural coral patches contained higher species richness (29 vs. 20) and coral diversity ( H' = 2.3 vs. 1.8). Multivariate analyses indicated strong differences between coral communities in natural and artificial habitats. Fish communities were sampled seasonally for 1 year. Multivariate fish communities differed significantly among habitat types in the summer and fall, but converged in the winter and spring. Univariate analysis indicated that species richness and abundance were stable throughout the year on natural coral patches but increased significantly in the summer on artificial reefs compared with the winter and spring, explaining the multivariate changes in community structure. The increased summer abundance on artificial reefs was mainly due to adult immigration. Piscivores were much more abundant in the fall than in the winter or spring on artificial reefs, but had low and stable abundance throughout the year in natural habitats. It is likely that the decreased winter and spring abundance of fish on the artificial reefs resulted from both predation and emigration. These results indicate that large artificial reefs can support diverse and abundant coral and fish communities. However, these communities differ structurally and functionally from those in natural habitats, and they should not be considered as replacements for natural coral and fish communities.

  18. Pelagic to demersal transition in a coral-reef fish, the orbicular batfish Platax orbicularis.

    PubMed

    Leis, J M; Hay, A C; Sasal, P; Hicks, A S; Galzin, R

    2013-09-01

    Behavioural and ecological observations were made on young, reared Platax orbicularis in Opunohu Bay, Moorea, French Polynesia, during their transition from the pelagic, dispersive stage to the reef-orientated demersal stage. Seventy-two young P. orbicularis (17-75 mm standard length, LS ) were released in the pelagic zone and 20 (40-70 mm LS ) adjacent to the reefs. Swimming speed was slow (mean 5·2 cm s(-1) ) and independent of size. An ontogenetic descent was observed: the smallest P. orbicularis swam at the surface, medium-sized P. orbicularis swam in midwater (mean 5-13 m) and the largest P. orbicularis swam to the bottom, where many lay on their sides. Platax orbicularis swam southerly on average, away from the ocean and into the bay. Smaller P. orbicularis were more likely to swim directionally than larger individuals. Young P. orbicularis released near reef edges swam at similar, but more variable speeds (mean 6·6 cm s(-1) ). About half of those released near reefs swam away, but fewer swam away from an inshore fringing reef than from a patch reef near the bay mouth. Many P. orbicularis swam up the slope onto the reef top, but the little settlement observed was near the reef base. Average, near-reef swimming direction was also southerly. Some reef residents, in particular the triggerfish Balistapus undulatus, harassed young P. orbicularis.

  19. Congruent patterns of connectivity can inform management for broadcast spawning corals on the Great Barrier Reef.

    PubMed

    Lukoschek, Vimoksalehi; Riginos, Cynthia; van Oppen, Madeleine J H

    2016-07-01

    Connectivity underpins the persistence and recovery of marine ecosystems. The Great Barrier Reef (GBR) is the world's largest coral reef ecosystem and managed by an extensive network of no-take zones; however, information about connectivity was not available to optimize the network's configuration. We use multivariate analyses, Bayesian clustering algorithms and assignment tests of the largest population genetic data set for any organism on the GBR to date (Acropora tenuis, >2500 colonies; >50 reefs, genotyped for ten microsatellite loci) to demonstrate highly congruent patterns of connectivity between this common broadcast spawning reef-building coral and its congener Acropora millepora (~950 colonies; 20 reefs, genotyped for 12 microsatellite loci). For both species, there is a genetic divide at around 19°S latitude, most probably reflecting allopatric differentiation during the Pleistocene. GBR reefs north of 19°S are essentially panmictic whereas southern reefs are genetically distinct with higher levels of genetic diversity and population structure, most notably genetic subdivision between inshore and offshore reefs south of 19°S. These broadly congruent patterns of higher genetic diversities found on southern GBR reefs most likely represent the accumulation of alleles via the southward flowing East Australia Current. In addition, signatures of genetic admixture between the Coral Sea and outer-shelf reefs in the northern, central and southern GBR provide evidence of recent gene flow. Our connectivity results are consistent with predictions from recently published larval dispersal models for broadcast spawning corals on the GBR, thereby providing robust connectivity information about the dominant reef-building genus Acropora for coral reef managers.

  20. Porites white patch syndrome: associated viruses and disease physiology

    NASA Astrophysics Data System (ADS)

    Lawrence, S. A.; Davy, J. E.; Wilson, W. H.; Hoegh-Guldberg, O.; Davy, S. K.

    2015-03-01

    In recent decades, coral reefs worldwide have undergone significant changes in response to various environmental and anthropogenic impacts. Among the numerous causes of reef degradation, coral disease is one factor that is to a large extent still poorly understood. Here, we characterize the physiology of white patch syndrome (WPS), a disease affecting poritid corals on the Great Barrier Reef. WPS manifests as small, generally discrete patches of tissue discolouration. Physiological analysis revealed that chlorophyll a content was significantly lower in lesions than in healthy tissues, while host protein content remained constant, suggesting that host tissue is not affected by WPS. This was confirmed by transmission electron microscope (TEM) examination, which showed intact host tissue within lesions. TEM also revealed that Symbiodinium cells are lost from the host gastrodermis with no apparent harm caused to the surrounding host tissue. Also present in the electron micrographs were numerous virus-like particles (VLPs), in both coral and Symbiodinium cells. Small (<50 nm diameter) icosahedral VLPs were significantly more abundant in coral tissue taken from diseased colonies, and there was an apparent, but not statistically significant, increase in abundance of filamentous VLPs in Symbiodinium cells from diseased colonies. There was no apparent increase in prokaryotic or eukaryotic microbial abundance in diseased colonies. Taken together, these results suggest that viruses infecting the coral and/or its resident Symbiodinium cells may be the causative agents of WPS.

  1. Repetitive reef to ooid sequences near leeward margin of Caicos Platform, British West Indies

    SciTech Connect

    Waltz, M.; Rossinsky, V.; Wanless, H.R.

    1987-05-01

    Drill core transects and outcrops near the leeward margin of the Caicos Platform, BWI, reveal repetitive (one Holocene and two Pleistocene) shallowing-upward sequences of either (a) reefal boundstones overlain by layered oolitic grainstones or (b) burrowed oolitic grainstones overlain by layered oolitic grainstones. Each sediment sequence is separated from the other by a calcrete exposure surface. A transect, perpendicular to the trend of an exposed Pleistocene barrier reef/ooid sand complex, shows two separate sediment packages of reefal boundstones and reef-derived skeletal packstones overlain by layered oolitic grainstones. The well-exposed upper package consists of a shallowing-upward barrier reef, which is immediately overlain by burrowed and cross-bedded oolitic grainstones, beach rock blocks, and coral rubble, capped by layered oolitic grainstones. Separated by an exposure horizon, the lowermost package consists of coral and skeletal sands overlain by layered oolitic grainstones. Cores from a transect in a non-reefal setting north of the barrier reef complex reveal highly burrowed oolitic grainstones capped by layered oolitic grainstones. As a Holocene example, immediately offshore of this transect, modern reefs and bioturbated oolitic grainstones are presently being buried beneath coral rubble, beach rock blocks, and prograding oolitic beaches. Deposition of the capping layered oolitic grainstones appears to occur during stable and falling sea levels. This co-occurrence of reefal sediment and ooid sands suggests that the two are not mutually exclusive and that reef-ooid succession is a reoccurring part of leeward margin platform margin-building.

  2. Low Florida coral calcification rates in the Plio-Pleistocene

    NASA Astrophysics Data System (ADS)

    Brachert, Thomas C.; Reuter, Markus; Krüger, Stefan; Klaus, James S.; Helmle, Kevin; Lough, Janice M.

    2016-08-01

    In geological outcrops and drill cores from reef frameworks, the skeletons of scleractinian corals are usually leached and more or less completely transformed into sparry calcite because the highly porous skeletons formed of metastable aragonite (CaCO3) undergo rapid diagenetic alteration. Upon alteration, ghost structures of the distinct annual growth bands often allow for reconstructions of annual extension ( = growth) rates, but information on skeletal density needed for reconstructions of calcification rates is invariably lost. This report presents the bulk density, extension rates and calcification rates of fossil reef corals which underwent minor diagenetic alteration only. The corals derive from unlithified shallow water carbonates of the Florida platform (south-eastern USA), which formed during four interglacial sea level highstands dated approximately 3.2, 2.9, 1.8, and 1.2 Ma in the mid-Pliocene to early Pleistocene. With regard to the preservation, the coral skeletons display smooth growth surfaces with minor volumes of marine aragonite cement within intra-skeletal porosity. Within the skeletal structures, voids are commonly present along centres of calcification which lack secondary cements. Mean extension rates were 0.44 ± 0.19 cm yr-1 (range 0.16 to 0.86 cm yr-1), mean bulk density was 0.96 ± 0.36 g cm-3 (range 0.55 to 1.83 g cm-3) and calcification rates ranged from 0.18 to 0.82 g cm-2 yr-1 (mean 0.38 ± 0.16 g cm-2 yr-1), values which are 50 % of modern shallow-water reef corals. To understand the possible mechanisms behind these low calcification rates, we compared the fossil calcification rates with those of modern zooxanthellate corals (z corals) from the Western Atlantic (WA) and Indo-Pacific calibrated against sea surface temperature (SST). In the fossil data, we found a widely analogous relationship with SST in z corals from the WA, i.e. density increases and extension rate decreases with increasing SST, but over a significantly larger

  3. Low Florida coral calcification rates in the Plio-Pleistocene

    NASA Astrophysics Data System (ADS)

    Brachert, T. C.; Reuter, M.; Krüger, S.; Klaus, J. S.; Helmle, K.; Lough, J. M.

    2015-12-01

    In geological outcrops and drill cores from reef frameworks, the skeletons of scleractinian corals are usually leached and more or less completely transformed into sparry calcite because the highly porous skeletons formed of metastable aragonite (CaCO3) undergo rapid diagenetic alteration. Upon alteration, ghost structures of the distinct annual growth bands may be retained allowing for reconstructions of annual extension (= growth) rates, but information on skeletal density needed for reconstructions of calcification rates is invariably lost. Here we report the first data of calcification rates of fossil reef corals which escaped diagenetic alteration. The corals derive from unlithified shallow water carbonates of the Florida platform (southeastern USA), which formed during four interglacial sea level highstands dated 3.2, 2.9, 1.8, and 1.2 Ma in the mid Pliocene to early Pleistocene. With regard to the preservation, the coral skeletons display smooth growth surfaces with minor volumes of marine aragonite cement within intra-skeletal porosity. Within the skeletal structures, dissolution is minor along centers of calcification. Mean extension rates were 0.44 ± 0.19 cm yr-1 (range 0.16 to 0.86 cm yr-1) and mean bulk density was 0.86 ± 0.36 g cm-3 (range 0.55 to 1.22 g cm-3). Correspondingly, calcification rates ranged from 0.18 to 0.82 g cm-2 yr-1 (mean 0.38 ± 0.16 g cm-2 yr-1), values which are 50 % of modern shallow-water reef corals. To understand the possible mechanisms behind these low calcification rates, we compared the fossil calcification with modern zooxanthellate-coral (z-coral) rates from the Western Atlantic (WA) and Indo-Pacific (IP) calibrated against sea surface temperature (SST). In the fossil data, we found an analogous relationship with SST in z-corals from the WA, i.e. density increases and extension rate decreases with increasing SST, but over a significantly larger temperature window during the Plio-Pleistocene. With regard to the

  4. Spin Glass Patch Planting

    NASA Technical Reports Server (NTRS)

    Wang, Wenlong; Mandra, Salvatore; Katzgraber, Helmut G.

    2016-01-01

    In this paper, we propose a patch planting method for creating arbitrarily large spin glass instances with known ground states. The scaling of the computational complexity of these instances with various block numbers and sizes is investigated and compared with random instances using population annealing Monte Carlo and the quantum annealing DW2X machine. The method can be useful for benchmarking tests for future generation quantum annealing machines, classical and quantum mechanical optimization algorithms.

  5. Research and analysis of patch shape on microstrip patch antenna

    NASA Astrophysics Data System (ADS)

    Ji, Ai-guo; Wang, Peng

    2017-01-01

    The shape of the radiating patch in the microstrip patch antenna is one of the many factors that affect the performance of the microstrip antenna.In this paper, on the premise of center frequency of 2.45 GHz, rectangular, circular and triangular microstrip patch antennas are designed and simulated respectively.The simulation results of the three microstrip patch antenna are analyzed, such as feed point position, return loss and radiation patterns.The influence of the shape of the radiation patch on the impedance bandwidth, gain and directivity of microstrip antennas is discussed.The simulation results show that the comprehensive performance of rectangular microstrip patch antenna is better than the other two, the comprehensive performance of triangular microstrip patch antenna is poor.

  6. Reef Education Evaluation: Environmental Knowledge and Reef Experience

    ERIC Educational Resources Information Center

    Stepath, Carl M.

    2005-01-01

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

  7. Anthropogenic perturbation of coral reef environments near Natal, Brazil: Clues from symbiont-bearing benthic foraminifera

    NASA Astrophysics Data System (ADS)

    Eichler, P.; Vital, H.; Sen Gupta, B. K.

    2014-12-01

    Besides global stressors such as temperature rise and acidification, local anthropogenic disturbances, especially those connected with tourism, affect many Atlantic patch reefs off the Brazilian shore. Using reef-inhabiting foraminifera with algal symbionts as environmental indicators, we confirmed this problem in coastal reefs near Natal, Rio Grande do Norte. The foraminiferal community is particularly depauperate in the small reefs of Pirangi, about 25 km south of Natal (~6o S, water depth <5-m), showing the result of numerous tourists trampling or otherwise damaging the reef substrate. Shells of Amphistegina gibbosa, the characteristic reef foraminifer of tropical America, have an exceptionally patchy distribution here, with rare living individuals. A few other symbiont bearers, e.g. Archaias angulatus, Amphisorus hemprichii, and Heterostegina antillarum, are present, but in extremely small numbers. In general, the dominant species is Quinqueloculina lamarckiana, a eurytopic, small miliolid (without symbionts), but many specimens are brown or black, indicating a mixing of relict and living populations. Compared to known foraminiferal communities in other Brazilian reefs, species diversity at Pirangi is remarkably low. About 77 km north of Pirangi, in the more extensive patch reef system of Maracajaú, the foraminiferal community is apparently healthier, except in an area targeted for tourism. However, living Amphistegina is still rare, and the only living Amphisorus is found in seagrass habitats. In contrast, many symbiont-bearing taxa, including peneroplids (virtually absent in Pirangi and Maracajaú) exist in sizeable populations northwest of Maracajaú, in the small patch reefs of the drowned Açu river valley (~4o 50' S).

  8. Great Barrier Reef

    NASA Technical Reports Server (NTRS)

    2002-01-01

    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.

  9. Protection of fish spawning habitat for the conservation of warm-temperature reef-fish fisheries of shelf-edge reefs of Florida

    USGS Publications Warehouse

    Koenig, Christopher C.; Coleman, Felicia C.; Grimes, Churchill B.; Fitzhugh, Gary R.; Scanlon, Kathyryn M.; Gledhill, Christopher T.; Grace, Mark

    2000-01-01

    We mapped and briefly describe the surficial geology of selected examples of shelf-edge reefs (50–120 m deep) of the southeastern United States, which are apparently derived from ancient Pleistocene shorelines and are intermittently distributed throughout the region. These reefs are ecologically significant because they support a diverse array of fish and invertebrate species, and they are the only aggregation spawning sites of gag (Mycteroperca microlepis), scamp (M. phenax), and other economically important reef fish. Our studies on the east Florida shelf in the Experimental Oculina Research Reserve show that extensive damage to the habitat-structuring coral Oculina varicosa has occurred in the past, apparently from trawling and dredging activities of the 1970s and later. On damaged or destroyed Oculina habitat, reef-fish abundance and diversity are low, whereas on intact habitat, reef-fish diversity is relatively high compared to historical diversity on the same site. The abundance and biomass of the economically important reef fish was much higher in the past than it is now, and spawning aggregations of gag and scamp have been lost or greatly reduced in size. On the west Florida shelf, fishers have concentrated on shelf-edge habitats for over 100 yrs, but fishing intensity increased dramatically in the 1980s. Those reefs are characterized by low abundance of economically important species. The degree and extent of habitat damage there is unknown. We recommend marine fishery reserves to protect habitat and for use in experimentally examining the potential production of unfished communities.

  10. Holocene reef development where wave energy reduces accommodation

    USGS Publications Warehouse

    Grossman, Eric E.; Fletcher, Charles H.

    2004-01-01

    Analyses of 32 drill cores obtained from the windward reef of Kailua Bay, Oahu, Hawaii, indicate that high wave energy significantly reduced accommodation space for reef development in the Holocene and produced variable architecture because of the combined influence of sea-level history and wave exposure over a complex antecedent topography. A paleostream valley within the late Pleistocene insular limestone shelf provided accommodation space for more than 11 m of vertical accretion since sea level flooded the bay 8000 yr BP. Virtually no net accretion (pile-up of fore-reef-derived rubble (rudstone) and sparse bindstone, and (3) a final stage of catch-up bindstone accretion in depths > 6 m. Coral framestone accreted at rates of 2.5-6.0 mm/yr in water depths > 11 m during the early Holocene; it abruptly terminated at ~4500 yr BP because of wave scour as sea level stabilized. More than 4 m of rudstone derived from the upper fore reef accreted at depths of 6 to 13 m below sea level between 4000 and 1500 yr BP coincident with late Holocene relative sea-level fall. Variations in the thickness, composition, and age of these reef facies across spatial scales of 10-1000 m within Kailua Bay illustrate the importance of antecedent topography and wave-related stress in reducing accommodation space for reef development set by sea level. Although accommodation space of 6 to 17 m has existed through most of the Holocene, the Kailua reef has been unable to catch up to sea level because of persistent high wave stress.

  11. Patch Test Negative Generalized Dermatitis.

    PubMed

    Spiker, Alison; Mowad, Christen

    2016-01-01

    Allergic contact dermatitis is a common condition in dermatology. Patch testing is the criterion standard for diagnosis. However, dermatitis is not always caused by an allergen, and patch testing does not identify a culprit in every patient. Generalized dermatitis, defined as eczematous dermatitis affecting greater than 3 body sites, is often encountered in dermatology practice, especially patch test referral centers. Management for patients with generalized dermatitis who are patch test negative is challenging. The purpose of this article is to outline an approach to this challenging scenario and summarize the paucity of existing literature on patch test negative generalized dermatitis.

  12. Vessel-to-Reef Projects

    EPA Pesticide Factsheets

    Using vessels as artificial reefs is an option for disposal. Artificial reefs serve to benefit the environment. Vessel-to-reef projects can follow the best management practices guidance. Guidance are provided for how to clean up vessels for use as reefs.

  13. Morphologies and depositional/erosional controls on evolution of Pliocene-Pleistocene carbonate platforms: Northern Carnarvon Basin, Northwest Shelf of Australia

    NASA Astrophysics Data System (ADS)

    Goktas, P.; Austin, J. A.; Fulthorpe, C. S.; Gallagher, S. J.

    2016-08-01

    The detailed morphologies, evolution and termination of latest Neogene tropical carbonate platforms in the Northern Carnarvon Basin (NCB), on the passive margin of the Northwest Shelf (NWS) of Australia, defined based upon mapping using 3D seismic images, reveal the history of local/regional oceanographic processes, fluctuations in relative sea-level and changing climate. Cool-water carbonate deposition, dominant during the early-middle Miocene, was followed by a siliciclastic influx, which prograded across the NWS beginning in the late-middle Miocene, during a period of long-term global sea-level fall. The resulting prograding clinoform sets, interpreted as delta lobes, created relict topographic highs following Pliocene termination of the siliciclastic influx. These highs constituted multiple favorable shallow-water environments for subsequent photozoan carbonate production. Resultant platform carbonate development, in addition to being a response to cessation of siliciclastic influx and the existence of suitable shallow-water substrate, was also influenced by development of the warm-water Leeuwin Current (LC), flowing southwestward along this margin. Four flat-topped platforms are mapped; each platform top is a sequence boundary defined by reflection onlap above and truncation below. Successive platforms migrated southwestward through time, along margin strike. All platforms exhibit predominantly progradational seismic geometries. Mapped tops are ≥10 km wide. Seismic evidence of karst on three of four platform tops, e.g., v-shaped troughs up to 50 m deep and ~1 km wide, and broader basins with areas up to 20 km2, suggests episodic subaerial exposure that may have contributed to platform demise. Platform 4, the most recent, is unique in having interpreted biohermal build-ups superimposed on the progradational platform base. The base of these interpreted patch reefs now lies at a water depth of ~153 m; therefore, we suggest that these reefs developed post

  14. A reappraisal of the diversity of geomorphological and genetic processes of New Caledonian coral reefs: a synthesis from optical remote sensing, coring and acoustic multibeam observations

    NASA Astrophysics Data System (ADS)

    Andréfouët, S.; Cabioch, G.; Flamand, B.; Pelletier, B.

    2009-09-01

    The diversity of oceanic and continental reef structures of New Caledonia is reviewed, taking into account their geological history and in particular, that since the last interglacial period. To guide this review, a new path is provided by following the diversity of units that have been mapped and characterized using high spatial resolution optical remote sensing data for the main New Caledonian coral reef complexes (banks, atolls, uplifted reefs, drowned reefs, fringing reefs, barrier reefs, patch reefs) and their individual reef-forming units. This interpretation, based on geomorphology, depth, and exposure has provided 161 unit types distributed across 4,537 km2 of reef area and 31,336 km2 of non-reef area. In addition to shallow reefs (0-30 m) described by optical remote sensing, the bathymetry of deep slopes between -20 to -1,000 m were recently mapped using multibeam acoustic data providing additional data to explain the morphological diversity. With the detailed three-dimensional topographic information acquired, hitherto unrecognized marine terraces and faulting became visible, indicating different episodes of formation of the barrier reef and of sea level variations. Finally, dating and coring corals provided a more accurate understanding of the genesis of the present reef structures. In contrast with the synoptic remote sensing data, cores provided only point data, but allowed the addition of a precise temporal dimension to the description of New Caledonian reefs. Cores provided a significant body of the information necessary for the establishment of models of reef settlement and development during the last interglacial ages in the New Caledonian region. The combined examination of the different sources of data, and the exhaustive description of remotely sensed reef units, allow a qualitative synoptic parallel to be drawn between the morphology of modern reefs and the contrasting patterns of reef growth, subsidence, and uplift rates occurring around New

  15. Using Fish Population Metrics to Compare the Effects of Artificial Reef Density

    PubMed Central

    2015-01-01

    Artificial reefs continue to be added as habitat throughout the world, yet questions remain about how reef design affects fish diversity and abundance. In the present study, the effects of reef density were assessed for fish communities and sizes of economically valuable Lutjanus campechanus 13 km off Port Mansfield, Texas, at a reef composed of more than 4000 concrete culverts. The study spanned from May to June in 2013 and 2014, and sites sampled included natural reefs, bare areas, and varying culvert patch density categories, ranging from 1–190 culverts. Abundances of adults and species evenness of juvenile populations differed between the years. Fish communities did not significantly differ among density categories; however, highest species richness and total abundances were observed at intermediate culvert densities and at natural reefs. Whereas the abundance of L. campechanus did not differ among density categories, mean total lengths of L. campechanus were greatest at the lower density. Our findings suggest that reefs should be deployed with intermediate patch density of 71–120 culverts in a 30-m radius to yield the highest fish abundances. PMID:26422472

  16. Polar Cap Patch Dynamics

    DTIC Science & Technology

    2013-04-25

    3 . Campaign periods for the 2010/2011 winter 3.1 Operation periods Ny-Ålesund 29 Nov - 13 Dec 2010 28 Dec - 10 Jan 2011 25 Jan - 8 Feb...dominated by a stable interplanetary magnetic field (IMF) B z < 0 and by an IMF B y > 0 situation. The aurora was characterized by a series of PMAFs...Svalbard Radar of two intense polar cap patch events on 6 February 2001. The interplanetary magnetic field (IMF) was dominated by a large positive By

  17. Patch antenna terahertz photodetectors

    SciTech Connect

    Palaferri, D.; Todorov, Y. Chen, Y. N.; Madeo, J.; Vasanelli, A.; Sirtori, C.; Li, L. H.; Davies, A. G.; Linfield, E. H.

    2015-04-20

    We report on the implementation of 5 THz quantum well photodetector exploiting a patch antenna cavity array. The benefit of our plasmonic architecture on the detector performance is assessed by comparing it with detectors made using the same quantum well absorbing region, but processed into a standard 45° polished facet mesa. Our results demonstrate a clear improvement in responsivity, polarization insensitivity, and background limited performance. Peak detectivities in excess of 5 × 10{sup 12} cmHz{sup 1/2}/W have been obtained, a value comparable with that of the best cryogenic cooled bolometers.

  18. Quaternary sedimentation and diagenesis in a high-latitude reef, Houtman Abrolhos Islands, Western Australia

    SciTech Connect

    Rosen, M.R.; Collins, L.B. ); Wyrwoll, K.H.; Hatcher, B.G. )

    1990-05-01

    The Houtman Abrolhos reefs are located 80 km off the west coast of Australia between latitudes 28 and 29{degree} south. The islands are situated on three Pleistocene carbonate reef platforms which rise above the surrounding shelf. The modern coral reefs are close to the geographic limit for coral growth in the southern hemisphere and survive due to the presence of the Leeuwin current (a poleward-flowing warm stream). Two major shallow-water benthic communities coexist in the Abrolhos: a macroalgal-dominated community on the windward platform margins and a coral-dominated community on the leeward margins. These communities overlap-particularly in the platform lagoons, where competition between macroalgae and corals is intense. This interaction has been suggested as a major factor controlling the growth of cord reefs at high latitudes. The Holocene carbonate sediments lack nonskeletal components and are dominated by coral and coralline algal fragments with subordinate molluskan and echinoderm debris. The accumulations can be grouped into the following major facies: (1) coral framestone and coralline algal/serpulid boundstone, (2) submarine sand sheets, (3) subaerial coral storm ridges, (4-) peritidal to subtidal shingle and rubble veneers composed of dominantly coral debris, and (5) eolian dunes and beach sand. The Holocene sediment is a thin (< 2 m) veneer on the Pleistocene reef platform, which is emergent as small islands. The Pleistocene platform is composed of reef facies that can be directly related to the Holocene sediments. The platform is composed of framestone and boundstone facies (corals and coralline algal/serpulid facies), rudstones (submarine coral rubble facies), planar-bedded skeletal grainstones dipping 12-13{degree} (submarine sand sheet and peritidal shingle facies), and large 15-m-high eolianite dunes (eolian dune facies).

  19. Patched Conic Trajectory Code

    NASA Technical Reports Server (NTRS)

    Park, Brooke Anderson; Wright, Henry

    2012-01-01

    PatCon code was developed to help mission designers run trade studies on launch and arrival times for any given planet. Initially developed in Fortran, the required inputs included launch date, arrival date, and other orbital parameters of the launch planet and arrival planets at the given dates. These parameters include the position of the planets, the eccentricity, semi-major axes, argument of periapsis, ascending node, and inclination of the planets. With these inputs, a patched conic approximation is used to determine the trajectory. The patched conic approximation divides the planetary mission into three parts: (1) the departure phase, in which the two relevant bodies are Earth and the spacecraft, and where the trajectory is a departure hyperbola with Earth at the focus; (2) the cruise phase, in which the two bodies are the Sun and the spacecraft, and where the trajectory is a transfer ellipse with the Sun at the focus; and (3) the arrival phase, in which the two bodies are the target planet and the spacecraft, where the trajectory is an arrival hyperbola with the planet as the focus.

  20. Statistics for Patch Observations

    NASA Astrophysics Data System (ADS)

    Hingee, K. L.

    2016-06-01

    In the application of remote sensing it is common to investigate processes that generate patches of material. This is especially true when using categorical land cover or land use maps. Here we view some existing tools, landscape pattern indices (LPI), as non-parametric estimators of random closed sets (RACS). This RACS framework enables LPIs to be studied rigorously. A RACS is any random process that generates a closed set, which encompasses any processes that result in binary (two-class) land cover maps. RACS theory, and methods in the underlying field of stochastic geometry, are particularly well suited to high-resolution remote sensing where objects extend across tens of pixels, and the shapes and orientations of patches are symptomatic of underlying processes. For some LPI this field already contains variance information and border correction techniques. After introducing RACS theory we discuss the core area LPI in detail. It is closely related to the spherical contact distribution leading to conditional variants, a new version of contagion, variance information and multiple border-corrected estimators. We demonstrate some of these findings on high resolution tree canopy data.

  1. Hosts of the Plio-Pleistocene past reflect modern-day coral vulnerability.

    PubMed

    van Woesik, Robert; Franklin, Erik C; O'Leary, Jennifer; McClanahan, Tim R; Klaus, James S; Budd, Ann F

    2012-06-22

    The risk of global extinction of reef-building coral species is increasing. We evaluated extinction risk using a biological trait-based resiliency index that was compared with Caribbean extinction during the Plio-Pleistocene, and with extinction risk determined by the International Union for Conservation of Nature (IUCN). Through the Plio-Pleistocene, the Caribbean supported more diverse coral assemblages than today and shared considerable overlap with contemporary Indo-Pacific reefs. A clear association was found between extant Plio-Pleistocene coral genera and our positive resilience scores. Regional extinction in the past and vulnerability in the present suggests that Pocillopora, Stylophora and foliose Pavona are among the most susceptible taxa to local and regional isolation. These same taxa were among the most abundant corals in the Caribbean Pliocene. Therefore, a widespread distribution did not equate with immunity to regional extinction. The strong relationship between past and present vulnerability suggests that regional extinction events are trait-based and not merely random episodes. We found several inconsistencies between our data and the IUCN scores, which suggest a need to critically re-examine what constitutes coral vulnerability.

  2. Pleistocene plants from North Carolina

    USGS Publications Warehouse

    Berry, Edward Wilber

    1926-01-01

    The field work upon which this report is based was done in 1906 and 1907 as a part of the cooperative study of the Atlantic Coastal Plain, under the direction of the late William Bullock Clark. Associated with the writer in this work were L. W. Stephenson, B. L. Miller, Jr., and J. E. Pogue. Preliminary accounts of the plants collected were published in 1907 and 1909. As has been frequently emphasized, the study of the Pleistocene floras in this country is in an exceedingly backward state as measured by the volume and precision of our knowledge of Pleistocene floras in Europe. Researches in Pleistocene geology in North America have been confined almost entirely to glaciology, and the problem of the correlation of the glacial deposits with those outside the glaciated area has not been solved, nor is there any general agreement regarding the genesis of the Pleistocene deposits south of the terminal moraines. The present account of what is known of the Pleistocene flora of North Carolina and the conclusions that may be legitimately derived from it is offered in the hope that it may stimulate an interest in a neglected field of research and form a small part of the evidence upon which to base future more comprehensive conclusions and generalizations. A word of explanation regarding the illustrations is required. Nearly all of them have been made from leaves preserved as carbonaceous films in the peaty clays. These specimens were carefully washed out, and blue prints were made directly from them. Outlines and as much of the venation as could be seen were inked on the blue prints, which were then bleached. This procedure made it possible to handle a much larger amount of material and prevented any possible damage to the exceedingly fragile specimens, which were mounted on cards or between glass. The accompanying drawings were made from tracings of the original nature prints.

  3. Improved Gain Microstrip Patch Antenna

    DTIC Science & Technology

    2015-08-06

    08-2015 Publication Improved Gain Microstrip Patch Antenna David A. Tonn Naval Under Warfare Center Division, Newport 1176 Howell St., Code 00L...Distribution A An antenna for mounting on a ground plane includes a dielectric substrate for mounting on the ground plane. A conductive patch...GAIN MICROSTRIP PATCH ANTENNA STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and used by or for the

  4. Plio-Pleistocene palaeogeography of the Llanura Costera del Caribe in eastern Hispaniola (Dominican Republic): Interplay of geomorphic evolution and sedimentation

    NASA Astrophysics Data System (ADS)

    Díaz de Neira, J. A.; Braga, J. C.; Mediato, J.; Lasseur, E.; Monthel, J.; Hernáiz, P. P.; Pérez-Cerdán, F.; Lopera, E.; Thomas, A.

    2015-07-01

    This paper aims to reconstruct the palaeogeographic evolution of the Llanura Costera del Caribe (LCC) in eastern Hispaniola (Dominican Republic) during the Pleistocene, adding new insights to published information on Pliocene-Early Pleistocene deposits. The LCC is a generally flat region comprising the unfolded sedimentary cover of the Cordilleras Central and Oriental. Within this cover, the Pliocene-Early Pleistocene Yanigua Formation,mainly consisting of marl, changes seawards to the mainly limestone Los Haitises Formation. Both units formed in a shallow-water platform rimmed by a reef barrier at least in the latest depositional stages. The overlying Pleistocene La Isabela Formation consists of two major offlapping reef terraces, in which a reef core enclosed a lagoon, and prograded over forereef bioclastic debris. Two belts in LCC's morphostructure directly reflect its sedimentary evolution. The Inner Belt extends over the marly substrate of the Yanigua Formation and the Coastal Belt comprises three major surfaces corresponding to the depositional top of the Los Haitises Formation (Upper Surface), and to the Upper and Lower terraces of the La Isabela Formation (Intermediate and Lower Surfaces, respectively). The MIS 5e age of the 10-20 m high Lower Terrace implies a low uplift rate of 0.033-0.068 mm/yr for the Lower Surface. The Pliocene-Early Pleistocene platform was emergent in the Early-Middle Pleistocene. The Early Pleistocene reef barrier separated endorheic watersheds extending over the former shelf lagoon from the open ocean. Reefs built the Upper Terrace of the La Isabela Formation during one or several Middle Pleistocene highstands and the Lower Terrace during MIS 5e and previous highstands. Siliciclastic deposits in this terrace record the opening to the Caribbean Sea of watersheds in the eastern LCC. The Lower Terrace emersion and opening of the large drainage systems of the western and central LCC took place after MIS 5e. Relative sea level fall and

  5. Australia's Great Barrier Reef

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Great Barrier Reef extends for 2,000 kilometers along the northeastern coast of Australia. It is not a single reef, but a vast maze of reefs, passages, and coral cays (islands that are part of the reef). This nadir true-color image was acquired by the MISR instrument on August 26, 2000 (Terra orbit 3679), and shows part of the southern portion of the reef adjacent to the central Queensland coast. The width of the MISR swath is approximately 380 kilometers, with the reef clearly visible up to approximately 200 kilometers from the coast. It may be difficult to see the myriad details in the browse image, but if you retrieve the higher resolution version, a zoomed display reveals the spectacular structure of the many reefs.

    The more northerly coastal area in this image shows the vast extent of sugar cane cultivation, this being the largest sugar producing area in Australia, centered on the city of Mackay. Other industries in the area include coal, cattle, dairying, timber, grain, seafood, and fruit. The large island off the most northerly part of the coast visible in this image is Whitsunday Island, with smaller islands and reefs extending southeast, parallel to the coast. These include some of the better known resort islands such as Hayman, Lindeman, Hamilton, and Brampton Islands.

    Further south, just inland of the small semicircular bay near the right of the image, is Rockhampton, the largest city along the central Queensland coast, and the regional center for much of central Queensland. Rockhampton is just north of the Tropic of Capricorn. Its hinterland is a rich pastoral, agricultural, and mining region.

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

  6. Coral Reef Ecosystems

    NASA Astrophysics Data System (ADS)

    Yap, Helen T.

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

  7. Potential spawning habitat for lake trout on Julian's Reef, Lake Michigan

    USGS Publications Warehouse

    Edsall, Thomas A.; Kennedy, Gregory W.

    1996-01-01

    Julian's Reef is an historical spawning ground for lake trout (Salvelinus namaycush) in southwestern Lake Michigan. It is a designated lake trout refuge and is the focus of lake trout restoration efforts in Illinois waters of the lake. We studied the reef to determine its potential as spawning habitat for stocked lake trout. We used side-scan sonar and a remotely operated vehicle equipped with a video camera to survey and map 156 ha of lake bed on the southeast portion of the reef, where an earlier study revealed the presence of loose-rock substrate potentially suitable for use by spawning lake trout. Our survey showed that the substrate on the reef that most closely resembled that described in the literature as suitable for spawning by stocked lake trout in the Great Lakes was rubble patches with interstitial depths greater than 20 cm. These rubble patches occupied about 2 ha of the 13-ha expanse of bedrock and rubble substrate near the reef crest in the surveyed area. We estimated that these rubble patches, if fully used by spawning lake trout, could accommodate egg deposition by at least 1,300–3,300 2.7-kg females.

  8. Persistence and change in community composition of reef corals through present, past, and future climates.

    PubMed

    Edmunds, Peter J; Adjeroud, Mehdi; Baskett, Marissa L; Baums, Iliana B; Budd, Ann F; Carpenter, Robert C; Fabina, Nicholas S; Fan, Tung-Yung; Franklin, Erik C; Gross, Kevin; Han, Xueying; Jacobson, Lianne; Klaus, James S; McClanahan, Tim R; O'Leary, Jennifer K; van Oppen, Madeleine J H; Pochon, Xavier; Putnam, Hollie M; Smith, Tyler B; Stat, Michael; Sweatman, Hugh; van Woesik, Robert; Gates, Ruth D

    2014-01-01

    The reduction in coral cover on many contemporary tropical reefs suggests a different set of coral community assemblages will dominate future reefs. To evaluate the capacity of reef corals to persist over various time scales, we examined coral community dynamics in contemporary, fossil, and simulated future coral reef ecosystems. Based on studies between 1987 and 2012 at two locations in the Caribbean, and between 1981 and 2013 at five locations in the Indo-Pacific, we show that many coral genera declined in abundance, some showed no change in abundance, and a few coral genera increased in abundance. Whether the abundance of a genus declined, increased, or was conserved, was independent of coral family. An analysis of fossil-reef communities in the Caribbean revealed changes in numerical dominance and relative abundances of coral genera, and demonstrated that neither dominance nor taxon was associated with persistence. As coral family was a poor predictor of performance on contemporary reefs, a trait-based, dynamic, multi-patch model was developed to explore the phenotypic basis of ecological performance in a warmer future. Sensitivity analyses revealed that upon exposure to thermal stress, thermal tolerance, growth rate, and longevity were the most important predictors of coral persistence. Together, our results underscore the high variation in the rates and direction of change in coral abundances on contemporary and fossil reefs. Given this variation, it remains possible that coral reefs will be populated by a subset of the present coral fauna in a future that is warmer than the recent past.

  9. Middle Devonian (Givetian) coral-stromatoporoid reefs in West Sahara (Morocco)

    NASA Astrophysics Data System (ADS)

    Wendt, Jobst; Kaufmann, Bernd

    2006-03-01

    Spectacular table reefs, biostromes and patch reefs occur in two areas (Uein Terguet and Gor Loutad) of West Sahara which are part of a narrow belt along the northern margin of the West African Craton (Reguibat Massif) extending for 1500 km from the Zemmour (Mauritania) in the SW to southern Algeria in the E. Six reef cycles can be distinguished in the Givetian which are separated by shales and sandstones. The first cycle is constituted by stromatactis mud mounds which probably also form the nucleus of the 2nd and 3rd reef cycle. The biota of the 2nd to 6th cycles are dominated by large stromatoporoids, associated with tabulate as well as solitary and colonial rugose corals and a great variety of reef-dwelling organisms. The cyclicity may be either a result of relative eustatic sealevel changes or of oscillating siliciclastic input from the West African Craton shelf margin which has repeatedly interrupted reef growth. Isotopic compositions of early cements in the 1st reef cycle indicate a cooler-water setting of about 40° S compared to coeval tropical low latitude reefs in Euramerica and Australia.

  10. Measuring coral reef terrain roughness using 'Structure-from-Motion' close-range photogrammetry

    NASA Astrophysics Data System (ADS)

    Leon, J. X.; Roelfsema, Chris M.; Saunders, Megan I.; Phinn, Stuart R.

    2015-08-01

    Our understanding of Earth surface processes is rapidly advancing as new remote sensing technologies such as LiDAR and close-range digital photogrammetry become more accessible and affordable. A very-high spatial resolution digital terrain model (DTM) and orthophoto mosaic (mm scale) were produced using close-range digital photogrammetry based on 'Structure-from-Motion' (SfM) algorithms for a 250 m transect along a shallow coral reef flat on Heron Reef, Great Barrier Reef. The precise terrain data were used to characterise surface roughness, a critical factor affecting ecological and physical processes on the reef. Three roughness parameters, namely the root mean square height, tortuosity (or rugosity) and fractal dimension, were derived and compared in order to asses which one better characterises reef flat roughness. The typical relief across the shallow reef flat was 0.1 m with a maximum value of 0.42 m. Coral reef terrain roughness, as characterised by the three chosen parameters, generally increased towards the middle of the transect where live coral covers most of the reef flat and decreases towards the edges of the transect. The fractal dimension (values ranging from 2.2 to 2.59) best characterised reef roughness, as evidenced by a closer agreement with the distribution of known coral benthic substrates. This is the first study quantifying scale-independent roughness of a coral reef at benthic and biotope/patch levels (cm-m). The readily available and cost-effective methods presented are highly appropriate for data collection, processing and analysis to generate very-high spatial resolution DTMs and orthophoto mosaics of shallow and energetic coral reefs.

  11. Observation of coral reefs on Ishigaki Island, Japan, using Landsat TM images and aerial photographs

    SciTech Connect

    Matsunaga, Tsuneo; Kayanne, Hajime

    1997-06-01

    Ishigaki Island is located at the southwestern end of Japanese Islands and famous for its fringing coral reefs. More than twenty LANDSAT TM images in twelve years and aerial photographs taken on 1977 and 1994 were used to survey two shallow reefs on this island, Shiraho and Kabira. Intensive field surveys were also conducted in 1995. All satellite images of Shiraho were geometrically corrected and overlaid to construct a multi-date satellite data set. The effects of solar elevation and tide on satellite imagery were studied with this data set. The comparison of aerial and satellite images indicated that significant changes occurred between 1977 and 1984 in Kabira: rapid formation in the western part and decrease in the eastern part of dark patches. The field surveys revealed that newly formed dark patches in the west contain young corals. These results suggest that remote sensing is useful for not only mapping but also monitoring of shallow coral reefs.

  12. Regional hard coral distribution within geomorphic and reef flat ecological zones determined by satellite imagery of the Xisha Islands, South China Sea

    NASA Astrophysics Data System (ADS)

    Zuo, Xiuling; Su, Fenzhen; Zhao, Huanting; Zhang, Junjue; Wang, Qi; Wu, Di

    2016-06-01

    Coral reefs in the Xisha Islands (also known as the Paracel Islands in English), South China Sea, have experienced dramatic declines in coral cover. However, the current regional scale hard coral distribution of geomorphic and ecological zones, essential for reefs management in the context of global warming and ocean acidification, is not well documented. We analyzed data from field surveys, Landsat-8 and GF-1 images to map the distribution of hard coral within geomorphic zones and reef flat ecological zones. In situ surveys conducted in June 2014 on nine reefs provided a complete picture of reef status with regard to live coral diversity, evenness of coral cover and reef health (live versus dead cover) for the Xisha Islands. Mean coral cover was 12.5% in 2014 and damaged reefs seemed to show signs of recovery. Coral cover in sheltered habitats such as lagoon patch reefs and biotic dense zones of reef flats was higher, but there were large regional differences and low diversity. In contrast, the more exposed reef slopes had high coral diversity, along with high and more equal distributions of coral cover. Mean hard coral cover of other zones was <10%. The total Xisha reef system was estimated to cover 1 060 km2, and the emergent reefs covered ~787 m2. Hard corals of emergent reefs were considered to cover 97 km2. The biotic dense zone of the reef flat was a very common zone on all simple atolls, especially the broader northern reef flats. The total cover of live and dead coral can reach above 70% in this zone, showing an equilibrium between live and dead coral as opposed to coral and algae. This information regarding the spatial distribution of hard coral can support and inform the management of Xisha reef ecosystems.

  13. Ethinyl Estradiol and Norelgestromin Transdermal Patch

    MedlinePlus

    ... the skin. One patch is applied once a week for 3 weeks, followed by a patch-free week. Follow the directions on your prescription label carefully, ... new patch on the same day of the week (the Patch Change Day). Apply a new patch ...

  14. Mesophotic bioerosion: Variability and structural impact on U.S. Virgin Island deep reefs

    NASA Astrophysics Data System (ADS)

    Weinstein, David K.; Smith, Tyler B.; Klaus, James S.

    2014-10-01

    Mesophotic reef corals, found 30-150 m below sea level, build complex structures that provide habitats for diverse ecosystems. Whereas bioerosion is known to impact the development and persistence of shallow reef structures, little is known regarding the extent of mesophotic bioerosion or how it might affect deeper reef geomorphology and carbonate accretion. Originally pristine experimental coral substrates and collected coral rubble were both used to investigate the variation and significance of mesophotic coral reef bioerosion south of St. Thomas, U.S. Virgin Islands. Bioerosion rates were calculated from experimental coral substrates exposed as framework for 1 and 2 years at four structurally distinct mesophotic coral reef habitats (between 30 and 45 m) as well as at a mid-shelf patch reef (21 m) and a shallow fringing patch reef (9 m). The long-term effects of macroboring were assessed by examining coral rubble collected at all sites. Overall, differences in bioerosional processes were found between shallow and mesophotic reefs. Increases in bioerosion on experimental substrates (amount of weight lost) were related to both decreasing seawater depth and increasing biomass of bioeroding parrotfish. Significant differences in coral skeleton bioerosion rates were also found between the transitional mesophotic reef zone (30-35 m) and the upper mesophotic reef zone (35-50 m) after 2 years of exposure, ranging from - 19.6 to 3.7 g/year. Total coral rubble macroboring was greater at most deep sites compared to shallower sites. Bioerosional grazing was found to dominate initial substrate modification in reefs 30.7 m and shallower, but sponges are believed to act as the main time-averaged long-term substrate bioeroders in reefs between 35 and 50 m. Although initial substrate bioerosion rates of a uniform substrate were relatively homogeneous in the 35-50 m depth zone, comparison of site composition suggests that mesophotic bioerosion will vary depending on the amount

  15. Late Pleistocene-Holocene geology of the central Virgin Island Platform

    USGS Publications Warehouse

    Holmes, C.W.; Kindinger, J.L.

    1985-01-01

    Geophysical and sedimentological data collected on the central Virgin Islands insular shelf provide a unique opportunity to investigate carbonate shelf processes in an active tectonic environment. Although complicated by fluctuating sea level during the Quaternary, the sedimentological regimes have been controlled by the tectonic fragmentation of the region. South of St. John, a northeast-southwest intrusive ridge controlled the development of the shallow geology. Profiles across this region, seaward of the ridge, indicate the existence of a buried wave-cut platform. Resting on this eroded surface, at the shelf break, is a reef having a topographic relief of 55 m. This reef, which formed a protective barrier preserving a sequence of lagoonal deposits, has been radiometrically determined to have died ???7000 yrs B.P., coinciding with the death of similar reefs in Florida and on the Island of St. Croix. South of St. Thomas, the strata are horizontal and are bisected by east-west midshelf faults. Truncation of the shelf edge strata, northern drainage, and unconformities on the northern shelf indicate that this block was tilted to the north during the late Pleistocene. This limited reef development to a narrow zone on the southern shelf edge. Geochemical, biological and sedimentological data indicate that the early to mid-Holocene was a time of vigorous shelf sedimentation. This accumulation peaked and abruptly stopped ???1200 yrs B.P., due to continued subsidence. Since this time, most sediment accumulation has been limited to the immediate area around the islands. ?? 1985.

  16. Pleistocene and pre-Pleistocene Begonia speciation in Africa.

    PubMed

    Plana, Vanessa; Gascoigne, Angus; Forrest, Laura L; Harris, David; Pennington, R Toby

    2004-05-01

    This paper presents a historical biogeographic analysis of African Begonia based on combined internal transcribed spacer (ITS) and trnL intron sequences. Age range estimates for Begonia in Africa ranged from only 1.5 Ma for some terminal nodes to 27 Ma for basal nodes when the ages of Réunion (2 Ma) andMayotte (5.4 Ma) were used to date the split between Begonia salaziensis and Begonia comorensis. Assuming a more recent origin age for Begonia salaziensis (2 Ma) provided age estimates in other parts of the phylogeny which agreed with patterns observed in other African organisms. A large proportion of the Begonia diversity seen today in Africa is of pre-Pleistocene origin. Species of Pleistocene origin are concentrated in species-rich groups such as sections Loasibegonia, Scutobegonia, and Tetraphila, which have their centre of diversity in western Central Africa. Phylogenetically isolated taxa such as Begonia longipetiolata, Begonia iucunda, and Begonia thomeana date to the late Miocene, a period of extended aridification on the African continent that had severe effects on African rain forest species. A general pattern is identified where phylogenetically isolated species occur outside the main identified rain forest refuges. Endemic species on the island of São Tomé such as Begonia baccata, Begonia molleri, and Begonia subalpestris appear to be palaeoendemics. Of these species, the most recent age estimate is for B. baccata, which is dated at ca. 3 Ma. Therefore, São Tomé appears to have functioned as an important (if previously unrecognised) pre-Pleistocene refuge. On the mainland, areas such as the Massif of Chaillu in Gabon, southern Congo (Brazzaville), and far western areas of Congo (Kinshasa) have played similar roles to São Tomé.

  17. Spatial differences and seasonal changes of net carbonate accumulation on some coral reefs of the Ryukyu Islands, Japan.

    PubMed

    Hibino; van Woesik R

    2000-09-05

    This study sought to understand short-term spatial changes in accretion and erosion on (experimental) carbonate blocks on three coral reefs of the Ryukyu Islands, Japan. The principal objectives were to differentiate net accretion/erosion according to season, location, depth and substrate-type. At all locations the summer season showed more positive net weight changes and higher coralline algal coverage than the winter season. Windward reefs revealed higher net accretion and higher coralline algal coverage than leeward reefs. Massive (Holocene) Porites blocks showed highest net loss, followed by Pleistocene carbonate and (Holocene) Acropora blocks. High population densities of Echinometra mathaei (de Blainville) were recorded on reefs adjacent to large human populations and overall net carbonate loss significantly correlated to densities of E. mathaei type A.

  18. Shelf stratigraphy and the influence of antecedent substrate on Holocene reef development, south Oahu, Hawaii

    USGS Publications Warehouse

    Grossman, E.E.; Barnhardt, W.A.; Hart, P.; Richmond, B.M.; Field, M.E.

    2006-01-01

    Paired analyses of drill cores and high-resolution seismic reflection data show that development of Holocene framework reefs on the Oahu (Hawaii) shelf is limited to settings of low wave energy and to the period 8000 to 3000 yr BP. A prominent bounding surface that is mapped across much of the Oahu shelf is an erosion surface cut into Marine Isotope Stages 5 and 7 limestones that show extensive loss of primary porosity, aragonite, and MgCO3 owing to meteoric and vadose-zone diagenesis. This acoustic reflector is found exposed at the surface where wave energy is high or in the shallow subsurface below Holocene reef and sand sheet deposits where energy is low. Ship-towed video along 30 km of the shelf reveals a steady decrease in limestone accumulation from offshore of Honolulu southeast to Koko Head where the seafloor is characterized by volcanic pavement and/or thin sand deposits. This may reflect the build-up of late Pleistocene volcanics associated with the Hanauma Bay eruption (30,000-7000 yr BP) that now comprise the substrate in depths shallow enough to limit reef accretion. The absence of significant Holocene reef build-up on the south Oahu shelf is consistent with observations from north-facing coasts that lack Holocene reefs, indicating that Holocene reef formation in Hawaii is complex and patchy. ?? 2005 Elsevier B.V. All rights reserved.

  19. Pleistocene and Holocene Iberian flora: a complete picture and review

    NASA Astrophysics Data System (ADS)

    González Sampériz, Penélope

    2010-05-01

    A detailed analysis of the location and composition of Iberian vegetation types during the whole Pleistocene and Holocene periods shows a complex patched landscape with persistence of different types of ecosystems, even during glacial times. In addition, recent, high-resolution palaeoecological records are changing the traditional picture of post-glacial vegetation succession in the Iberian Peninsula. The main available charcoal and pollen sequences include, coniferous and deciduous forest, steppes, shrublands, savannahs and glacial refugia during the Pleistocene for Meso-thermophytes (phytodiversity reservoirs), in different proportions. This panorama suggests an environmental complexity that relates biotic responses to climate changes forced by Milankovitch cycles, suborbital forcings and by the latitudinal and physiographic particularities of the Iberian Peninsula. Thus, many factors are critical in the course of vegetational developments and strong regional differences are observed since the Early Pleistocene. Currently, the flora of Iberia is located in two biogeographical/climatic regions: the Eurosiberian and the Mediterranean. The first one includes northern and northwestern areas of the peninsula, where post-glacial responses of vegetation are very similar to Central Europe, although with some particularities due to its proximity to both the Atlantic Ocean and the Mediterranean region. The second one comprises the main territory of Iberia and shows more complex patterns and singularities, now and in the past. Steppe landscapes dominated extensive areas over all the territory during the cold spells of the Quaternary, especially during the Late Pleistocene up to the Last Glacial Maximum, but differences in composition of the dominant taxa (Compositae versus Artemisia) are observed since the Early Pleistocene, probably related to moisture regional gradients. Coastal shelves and intramountainous valleys, even in continental areas, are spots of floristic

  20. Interactive effects of live coral and structural complexity on the recruitment of reef fishes

    NASA Astrophysics Data System (ADS)

    Coker, D. J.; Graham, N. A. J.; Pratchett, M. S.

    2012-12-01

    Corals reefs are subjected to multiple disturbances that modify levels of coral cover and structural complexity of the reef matrix, and in turn influence the structure of associated fish communities. With disturbances predicted to increase, insight into how changes in substrate condition will influence the recruitment of many fishes is essential for understanding the recovery of reef fish populations following biological and physical disturbances. While studies have revealed that both live coral cover and structural complexity are important for many fishes, there is a lack of understanding regarding how a combination of these changes will impact the recruitment of fishes. This study used experimentally constructed patch reefs consisting of six different habitat treatments; three levels of live coral cover (high, medium, low) crossed with two levels of structural complexity (high, low), to test the independent and combined effects of live coral cover and structural complexity on the recruitment and recovery of fish communities. The abundance and species diversity of fishes varied significantly among the six habitat treatments, but differences were not clearly associated with either coral cover or structural complexity and varied through time. More striking, however, was a significant difference in the composition of fish assemblages among treatments, due mostly to disproportionate abundance of coral-dwelling fishes on high coral cover, high complexity reefs. Overall, it appears that coral cover had a more important influence than structural complexity, at least for the contrasting levels of structural complexity achieved on experimental patch reefs. Furthermore, we found that live coral cover is important for the recruitment of some non-coral-dependent fishes. This study confirms that live coral cover is critical for the maintenance of high biodiversity on tropical coral reefs, and that sustained and ongoing declines in coral cover will adversely affect recruitment

  1. Coral reef resilience through biodiversity

    USGS Publications Warehouse

    Rogers, Caroline S.

    2013-01-01

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

  2. Long-Term Effects of the Cleaner Fish Labroides dimidiatus on Coral Reef Fish Communities

    PubMed Central

    Waldie, Peter A.; Blomberg, Simon P.; Cheney, Karen L.; Goldizen, Anne W.; Grutter, Alexandra S.

    2011-01-01

    Cleaning behaviour is deemed a mutualism, however the benefit of cleaning interactions to client individuals is unknown. Furthermore, mechanisms that may shift fish community structure in the presence of cleaning organisms are unclear. Here we show that on patch reefs (61–285 m2) which had all cleaner wrasse Labroides dimidiatus (Labridae) experimentally removed (1–5 adults reef−1) and which were then maintained cleaner-fish free over 8.5 years, individuals of two site-attached (resident) client damselfishes (Pomacentridae) were smaller compared to those on control reefs. Furthermore, resident fishes were 37% less abundant and 23% less species rich per reef, compared to control reefs. Such changes in site-attached fish may reflect lower fish growth rates and/or survivorship. Additionally, juveniles of visitors (fish likely to move between reefs) were 65% less abundant on removal reefs suggesting cleaners may also affect recruitment. This may, in part, explain the 23% lower abundance and 33% lower species richness of visitor fishes, and 66% lower abundance of visitor herbivores (Acanthuridae) on removal reefs that we also observed. This is the first study to demonstrate a benefit of cleaning behaviour to client individuals, in the form of increased size, and to elucidate potential mechanisms leading to community-wide effects on the fish population. Many of the fish groups affected may also indirectly affect other reef organisms, thus further impacting the reef community. The large-scale effect of the presence of the relatively small and uncommon fish, Labroides dimidiadus, on other fishes is unparalleled on coral reefs. PMID:21731670

  3. Cambrian Series 3 carbonate platform of Korea dominated by microbial-sponge reefs

    NASA Astrophysics Data System (ADS)

    Hong, Jongsun; Lee, Jeong-Hyun; Choh, Suk-Joo; Lee, Dong-Jin

    2016-07-01

    Metazoans have been considered as negligible components of Cambrian Series 3 and Furongian microbial-dominated reefs, in contrast to their presence in earlier Terreneuvian-Cambrian Series 2 microbial-archaeocyath reefs. However, recent discoveries of sponges in Cambrian Series 3-Furongian reefs of Australia, China, Iran, USA, and Korea have raised question regarding their contribution in terms of carbonate platform development, which have never been assessed. This study examines Cambrian Series 3 deposits of the Daegi Formation, Korea to elucidate this question. The 100-m-thick middle part of the Daegi Formation is dominated by boundstone facies, which occupies 45% of the study interval, as well as bioclastic wackestone to packstone, bioclastic grainstone, and ooid packstone to grainstone facies. The Daegi reefs are primarily thrombolitic in composition, with 90% (n = 26/29) of the reefs containing an average of 9% sponges in aerial percentage calculated from thin sections. Lithistid sponges composed of peloidal fabrics, some desma spicules, and spicule networks commonly occupy the interstitial space in microbial clusters, are encrusted by mesoclots and Epiphyton, and are surrounded by micrite. Subordinate non-lithistid demosponges occur within clusters of microbial elements. The middle Daegi Formation can be largely subdivided into shoal environment dominated by grainstone to packstone facies and shallow subtidal platform interior environment located behind shoal with wackestone to packstone facies. The microbial-sponge reefs mainly developed around platform interior as patch reefs. The current study indicates that metazoans in the form of lithistid and non-lithistid demosponges are nearly ubiquitously incorporated in Daegi reefs and contributed greatly to the formation of microbial-sponge reefs as well as carbonate platform during the time. Study of these microbial-sponge reefs and their distribution within the carbonate platform may help us to understand how

  4. The evolution of reef communities

    SciTech Connect

    Fagerstrom, J.A.

    1987-01-01

    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.

  5. Benthic communities at two remote Pacific coral reefs: effects of reef habitat, depth, and wave energy gradients on spatial patterns.

    PubMed

    Williams, Gareth J; Smith, Jennifer E; Conklin, Eric J; Gove, Jamison M; Sala, Enric; Sandin, Stuart A

    2013-01-01

    Kingman Reef and Palmyra Atoll in the central Pacific are among the most remote coral reefs on the planet. Here we describe spatial patterns in their benthic communities across reef habitats and depths, and consider these in the context of oceanographic gradients. Benthic communities at both locations were dominated by calcifying organisms (54-86% cover), namely hard corals (20-74%) and crustose coralline algae (CCA) (10-36%). While turf algae were relatively common at both locations (8-22%), larger fleshy macroalgae were virtually absent at Kingman (<1%) and rare at Palmyra (0.7-9.3%). Hard coral cover was higher, but with low diversity, in more sheltered habitats such as Palmyra's backreef and Kingman's patch reefs. Almost exclusive dominance by slow-growing Porites on Kingman's patch reefs provides indirect evidence of competitive exclusion, probably late in a successional sequence. In contrast, the more exposed forereef habitats at both Kingman and Palmyra had higher coral diversity and were characterized by fast-growing corals (e.g., Acropora and Pocillopora), indicative of more dynamic environments. In general at both locations, soft coral cover increased with depth, likely reflecting increasingly efficient heterotrophic abilities. CCA and fleshy macroalgae cover decreased with depth, likely due to reduced light. Cover of other calcified macroalgae, predominantly Halimeda, increased with depth. This likely reflects the ability of many calcifying macroalgae to efficiently harvest light at deeper depths, in combination with an increased nutrient supply from upwelling promoting growth. At Palmyra, patterns of hard coral cover with depth were inconsistent, but cover peaked at mid-depths at Kingman. On Kingman's forereef, benthic community composition was strongly related to wave energy, with hard coral cover decreasing and becoming more spatially clustered with increased wave energy, likely as a result of physical damage leading to patches of coral in localized

  6. Benthic communities at two remote Pacific coral reefs: effects of reef habitat, depth, and wave energy gradients on spatial patterns

    PubMed Central

    Conklin, Eric J.; Gove, Jamison M.; Sala, Enric; Sandin, Stuart A.

    2013-01-01

    Kingman Reef and Palmyra Atoll in the central Pacific are among the most remote coral reefs on the planet. Here we describe spatial patterns in their benthic communities across reef habitats and depths, and consider these in the context of oceanographic gradients. Benthic communities at both locations were dominated by calcifying organisms (54–86% cover), namely hard corals (20–74%) and crustose coralline algae (CCA) (10–36%). While turf algae were relatively common at both locations (8–22%), larger fleshy macroalgae were virtually absent at Kingman (<1%) and rare at Palmyra (0.7–9.3%). Hard coral cover was higher, but with low diversity, in more sheltered habitats such as Palmyra’s backreef and Kingman’s patch reefs. Almost exclusive dominance by slow-growing Porites on Kingman’s patch reefs provides indirect evidence of competitive exclusion, probably late in a successional sequence. In contrast, the more exposed forereef habitats at both Kingman and Palmyra had higher coral diversity and were characterized by fast-growing corals (e.g., Acropora and Pocillopora), indicative of more dynamic environments. In general at both locations, soft coral cover increased with depth, likely reflecting increasingly efficient heterotrophic abilities. CCA and fleshy macroalgae cover decreased with depth, likely due to reduced light. Cover of other calcified macroalgae, predominantly Halimeda, increased with depth. This likely reflects the ability of many calcifying macroalgae to efficiently harvest light at deeper depths, in combination with an increased nutrient supply from upwelling promoting growth. At Palmyra, patterns of hard coral cover with depth were inconsistent, but cover peaked at mid-depths at Kingman. On Kingman’s forereef, benthic community composition was strongly related to wave energy, with hard coral cover decreasing and becoming more spatially clustered with increased wave energy, likely as a result of physical damage leading to patches of

  7. Coral reef sedimentation on Rodrigues and the Western Indian Ocean and its impact on the carbon cycle.

    PubMed

    Rees, Siwan A; Opdyke, Bradley N; Wilson, Paul A; Fifield, L Keith

    2005-01-15

    Coral reefs in the southwest Indian Ocean cover an area of ca. 18,530 km2 compared with a global reef area of nearly 300,000 km2. These regions are important as fishing grounds, tourist attractions and as a significant component of the global carbon cycle. The mass of calcium carbonate stored within Holocene neritic sediments is a number that we are only now beginning to quantify with any confidence, in stark contrast to the mass and sedimentation rates associated with pelagic calcium carbonate, which have been relatively well defined for decades. We report new data that demonstrate that the reefs at Rodrigues, like those at Reunion and Mauritius, only reached a mature state (reached sea level) by 2-3 ka: thousands of years later than most of the reefs in the Australasian region. Yet field observations show that the large lagoon at Rodrigues is already completely full of carbonate detritus (typical lagoon depth less than 1 m at low spring tide). The presence of aeolian dunes at Rodrigues indicates periodic exposure of past lagoons throughout the Pleistocene. The absence of elevated Pleistocene reef deposits on the island indicates that the island has not been uplifted. Most Holocene reefs are between 15 and 20 m in thickness and those in the southwest Indian Ocean appear to be consistent with this observation. We support the view that the CO2 flux associated with coral-reef growth acts as a climate change amplifier during deglaciation, adding CO2 to a warming world. southwest Indian Ocean reefs could have added 7-10% to this global flux during the Holocene.

  8. Synthesizing mechanisms of density dependence in reef fishes: behavior, habitat configuration, and observational scale.

    PubMed

    White, J Wilson; Samhouri, Jameal F; Stier, Adrian C; Wormald, Clare L; Hamilton, Scott L; Sandin, Stuart A

    2010-07-01

    Coral and rocky reef fish populations are widely used as model systems for the experimental exploration of density-dependent vital rates, but patterns of density-dependent mortality in these systems are not yet fully understood. In particular, the paradigm for strong, directly density-dependent (DDD) postsettlement mortality stands in contrast to recent evidence for inversely density-dependent (IDD) mortality. We review the processes responsible for DDD and IDD per capita mortality in reef fishes, noting that the pattern observed depends on predator and prey behavior, the spatial configuration of the reef habitat, and the spatial and temporal scales of observation. Specifically, predators tend to produce DDD prey mortality at their characteristic spatial scale of foraging, but prey mortality is IDD at smaller spatial scales due to attack-abatement effects (e.g., risk dilution). As a result, DDD mortality may be more common than IDD mortality on patch reefs, which tend to constrain predator foraging to the same scale as prey aggregation, eliminating attack-abatement effects. Additionally, adjacent groups of prey on continuous reefs may share a subset of refuges, increasing per capita refuge availability and relaxing DDD mortality relative to prey on patch reefs, where the patch edge could prevent such refuge sharing. These hypotheses lead to a synthetic framework to predict expected mortality patterns for a variety of scenarios. For nonsocial, nonaggregating species and species that aggregate in order to take advantage of spatially clumped refuges, IDD mortality is possible but likely superseded by DDD refuge competition, especially on patch reefs. By contrast, for species that aggregate socially, mortality should be IDD at the scale of individual aggregations but DDD at larger scales. The results of nearly all prior reef fish studies fit within this framework, although additional work is needed to test many of the predicted outcomes. This synthesis reconciles some

  9. Ocean acidification refugia of the Florida Reef Tract.

    PubMed

    Manzello, Derek P; Enochs, Ian C; Melo, Nelson; Gledhill, Dwight K; Johns, Elizabeth M

    2012-01-01

    Ocean acidification (OA) is expected to reduce the calcification rates of marine organisms, yet we have little understanding of how OA will manifest within dynamic, real-world systems. Natural CO(2), alkalinity, and salinity gradients can significantly alter local carbonate chemistry, and thereby create a range of susceptibility for different ecosystems to OA. As such, there is a need to characterize this natural variability of seawater carbonate chemistry, especially within coastal ecosystems. Since 2009, carbonate chemistry data have been collected on the Florida Reef Tract (FRT). During periods of heightened productivity, there is a net uptake of total CO(2) (TCO(2)) which increases aragonite saturation state (Ω(arag)) values on inshore patch reefs of the upper FRT. These waters can exhibit greater Ω(arag) than what has been modeled for the tropical surface ocean during preindustrial times, with mean (± std. error) Ω(arag)-values in spring = 4.69 (±0.101). Conversely, Ω(arag)-values on offshore reefs generally represent oceanic carbonate chemistries consistent with present day tropical surface ocean conditions. This gradient is opposite from what has been reported for other reef environments. We hypothesize this pattern is caused by the photosynthetic uptake of TCO(2) mainly by seagrasses and, to a lesser extent, macroalgae in the inshore waters of the FRT. These inshore reef habitats are therefore potential acidification refugia that are defined not only in a spatial sense, but also in time; coinciding with seasonal productivity dynamics. Coral reefs located within or immediately downstream of seagrass beds may find refuge from OA.

  10. Multi-site evaluation of IKONOS data for classification of tropical coral reef environments

    USGS Publications Warehouse

    Andrefouet, S.; Kramer, Philip; Torres-Pulliza, D.; Joyce, K.E.; Hochberg, E.J.; Garza-Perez, R.; Mumby, P.J.; Riegl, Bernhard; Yamano, H.; White, W.H.; Zubia, M.; Brock, J.C.; Phinn, S.R.; Naseer, A.; Hatcher, B.G.; Muller-Karger, F. E.

    2003-01-01

    Ten IKONOS images of different coral reef sites distributed around the world were processed to assess the potential of 4-m resolution multispectral data for coral reef habitat mapping. Complexity of reef environments, established by field observation, ranged from 3 to 15 classes of benthic habitats containing various combinations of sediments, carbonate pavement, seagrass, algae, and corals in different geomorphologic zones (forereef, lagoon, patch reef, reef flats). Processing included corrections for sea surface roughness and bathymetry, unsupervised or supervised classification, and accuracy assessment based on ground-truth data. IKONOS classification results were compared with classified Landsat 7 imagery for simple to moderate complexity of reef habitats (5-11 classes). For both sensors, overall accuracies of the classifications show a general linear trend of decreasing accuracy with increasing habitat complexity. The IKONOS sensor performed better, with a 15-20% improvement in accuracy compared to Landsat. For IKONOS, overall accuracy was 77% for 4-5 classes, 71% for 7-8 classes, 65% in 9-11 classes, and 53% for more than 13 classes. The Landsat classification accuracy was systematically lower, with an average of 56% for 5-10 classes. Within this general trend, inter-site comparisons and specificities demonstrate the benefits of different approaches. Pre-segmentation of the different geomorphologic zones and depth correction provided different advantages in different environments. Our results help guide scientists and managers in applying IKONOS-class data for coral reef mapping applications. ?? 2003 Elsevier Inc. All rights reserved.

  11. Effects of oyster dredging on the distribution of bryozoan biogenic reefs and associated sediments in Foveaux Strait, southern New Zealand

    NASA Astrophysics Data System (ADS)

    Cranfield, H. J.; Manighetti, B.; Michael, K. P.; Hill, A.

    2003-09-01

    Foveaux Strait has been commercially fished for oysters for over 100 years, focusing principally upon bryozoan biogenic reefs that once covered large areas of the strait. Bryozoan biogenic reefs consisted of linear swards of bryozoan patch reefs, paralleling the peak tidal current, and were formed by the frame-building bryozoan Cinctipora elegans and associated epifauna. Two side-scan surveys one in the late 1970s and the other in the late 1990s and estimates of distribution of oyster density and distribution of fishing effort, show how fishing has effected the distribution of habitat, oysters and sediments over the last 30 years. Fishers dredged the biogenic reefs for their oysters, damaging the framework structure, removing epifauna and exposing associated sediments, which were then reworked and transported down-current in the strong tidal flow. Large volumes of biogenic sediments released in this process formed thick sheets and dune bedforms. When dredging ceased locally (after removal of biogenic reef habitat and oysters), sediment supply downstream dwindled and ceased, bedforms diminished and the seafloor ultimately reverted to relict pebble gravel. Sediment derived from the dredging of biogenic reefs in northern Foveaux Strait was mostly transported and deposited in deeper water to the east, however, sediment derived from biogenic reefs in southern Foveaux Strait was transported in the opposite direction, giving rise to a group of large dunes in the southwest that in 1999 contained ˜58×10 6 m 3 of coarse biogenic sediment. By 1998 none of the original bryozoan biogenic reefs remained. We interpret sediment distribution in Foveaux Strait in the light of these processes, and compare with earlier data to provide snapshots of human-induced modification of the benthic environment. We also explore evidence for regeneration of simple biogenic reefs in areas no longer fished, and discuss the conditions in which this has occurred. Communities dominated by byssally

  12. Size variation in Middle Pleistocene humans.

    PubMed

    Arsuaga, J L; Carretero, J M; Lorenzo, C; Gracia, A; Martínez, I; Bermúdez de Castro, J M; Carbonell, E

    1997-08-22

    It has been suggested that European Middle Pleistocene humans, Neandertals, and prehistoric modern humans had a greater sexual dimorphism than modern humans. Analysis of body size variation and cranial capacity variation in the large sample from the Sima de los Huesos site in Spain showed instead that the sexual dimorphism is comparable in Middle Pleistocene and modern populations.

  13. Character release following extinction in a Caribbean reef coral species complex.

    PubMed

    Pandolfi, John M; Lovelock, Catherine E; Budd, Ann F

    2002-03-01

    The Pleistocene extinction of the widespread organ-pipe Montastraea coral had measurable morphological and ecological effects on surviving lineages of the Montastraea "annularis" species complex. Extinction of the organ-pipe Montastraea occurred after more than 500,000 years of dominance in the shallow-water reef habitat of Barbados. Extinction resulted in a morphological shift of the columnar Montastraea lineage from thick to thin columns in modern reef environments. Pleistocene colonies of the columnar morphotype sympatric with organ-pipe Montastraea showed greater column widths than those in allopatry. We subjected our data to a number of criteria for interpreting the morphological shift as character release following lifting of competitive pressure after extinction. The morphological differences do not appear to be due either to chance or to physical properties of the marine environment. Differential local extinction and recolonization of four members of the species complex did not occur on Barbados, so that the species coexisted and appear to have coevolved between more than 600,000 and 82,000 years ago. The morphological shift is related to coral growth form and growth rate, and thus reflects the acquisition of a primary resource in corals--light. Character release occurred at the same oceanic Caribbean island (Barbados) where environments have fluctuated with similar variance throughout the period of coexistence. Not only has competition among living members of the Montastraea "annularis" species complex been convincingly demonstrated, but trends in relative abundance among fossil members of the species complex strongly suggest that a competitive hierarchy was operating during their Pleistocene coexistence on Barbados. We also observed an ecological analogue to character release on another Caribbean island. Curaçao. The distribution and abundance of living columnar M. annularis s.s. and massive M. faveolata from the leeward reef crest in Curaçao is greater

  14. Pleistocene to Recent deep-coral growth on peri-Ionian escarpments, Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Taviani, M.; Corselli, C.; Freiwald, A.; Malinverno, E.; Mastrototaro, F.; Remia, A.; Savini, A.; Tursi, A.

    2003-04-01

    Significant growth of deep-sea cold-water coral build-ups is well documented in the Mediterranean basin since the late Pliocene at least. Early-Middle Pleistocene coral assemblages made up by the scleractinian triad Lophelia-Madrepora-Desmophyllum (LMD), crop out locally in areas subjected to considerable neotectonic uplift, i.e. Calabria, Sicily and Rhodes. Furthermore, submerged LMD build-ups, mostly dated to the latest Pleistocene, are common and widespread in the entire basin. LMD communities were severely impacted by post-glacial modifications of the Mediterranean oceanography that caused their general decline in this basin. As a result, the distribution of surviving LMD communities is today quite patchy in the Mediterranean Sea and this is especially true for the branching scleractinian Lophelia. The Ionian Sea is no exception and Pleistocene deep-coral thanatocoenoses are present on sediment-starved, rocky escarpments rimming this sub-basin. However, astonishingly healthy LMD banks dominated by living colonies of Lophelia prolifera, have been recently discovered on the eastern side of the Ionian Sea. The living coral banks are located on a gently dipping shelf offshore the Apulian coast at depths comprised between 300-1000 m. Side Scan Sonar, high-resolution seismic and direct sampling indicate that these Lophelia reefs colonize quasi-indurate Pleistocene sediment. By comparison with modern Eastern Atlantic and Pleistocene Mediterranean counterparts, these modern coral banks display a lesser-diversified associated invertebrate fauna. Finally, a direct link between the occurrence of these coral banks and seepage of hydrocarbons is not evident.

  15. Miocene reefs evolution within the shelf carbonates and fan delta complexes of the Antalya basin, southern Turkey

    NASA Astrophysics Data System (ADS)

    Karabiyikoglu, M.; Çiner, A.; Tuzcu, S.

    2003-04-01

    Coral reefs provide sensitive records of tectonics, climatic and sea-level changes as well as palaeoecological conditions of the environmental settings that prevailed during their development. Miocene coral reefs and reef-derived sediments are common constituents of the clastic-dominated succession of the late orogenic depositional fill of the Late Cenozoic Antalya Basin (subdivided into Manavgat, Köprüçay and Aksu sub-basins) in the western Taurides Mountains. Two distinct developments of coral reefs have been recognised: 1) Late Burdigalian-Langhian reefs: They occur as massive, small, isolated, mound-like patch reefs formed on clast-supported conglomerate facies of fan delta and algal-foraminiferal wacke-packstone facies of transgressive open shelf carbonates within the Manavgat and the Köprüçay sub-basins. They are characterized by a massive reef core facies, largely made-up of rich and diversified Faviidae (Porites, Stylophora) dominated hermatypic coral colonies comprising occasional single corals (Mussidae, Caryophyllidae) reflecting relative changes in the bathimetry. The hermatypic coral colonies are mainly composed of massive, domal and branching forms without any distinct zonation within the reef framework. Abundant calcareous algae, bryozoans, bivalves, echinoids, gastropods and benthic and planktic foraminifers are also common within the reef bodies. 2) Tortonian-Messinian reefs: They only occur in the Aksu sub-basin as massive, relatively larger, oval bodies developed on clast-supported conglomerate facies of coastal alluvial fan/fan-delta complexes that formed in a paralic-shallow marine setting. The reef framework is characteristically dominated by Porites (branching and nodular forms) with subordinate Tarbellastraea and rare Siderastraea (massive globular forms), Plesiastraea and Favites. The Miocene coral reef growth and development in the western Taurides are closely related to the complex interaction of sporadic influxes of coarse

  16. Estimating the role of three mesopredatory fishes in coral reef food webs at Ningaloo Reef, Western Australia

    NASA Astrophysics Data System (ADS)

    Thillainath, Emma C.; McIlwain, Jennifer L.; Wilson, Shaun K.; Depczynski, Martial

    2016-03-01

    Within the complex food webs that occur on coral reefs, mesopredatory fish consume small-bodied prey and transfer accumulated biomass to other trophic levels. We estimated biomass, growth and mortality rates of three common mesopredators from Ningaloo Reef in Western Australia to calculate their annual turnover rates and potential contribution to local trophic dynamics. Biomass estimates of the serranid Epinephelus rivulatus (4.46 ± 0.76 g m-2) were an order of magnitude greater than two smaller-bodied mesopredatory fishes, Pseudochromis fuscus (0.10 ± 0.03 g m-2) and Parapercis clathrata (0.23 ± 0.31 g m-2). Growth parameters generated from a von Bertalanffy growth function fitted to size-at-age data, however, indicated that mortality rates for the three mesopredators were similar and that 32-55 % of fish survived each year. Consequently, interspecific differences in annual turnover rates among E. rivulatus (1.9 g m-2 yr-1), Pa. clathrata (0.10 g m-2 yr-1) and Ps. fuscus (0.07 g m-2 yr-1) were an artefact of differences in local biomass estimates. The rapid turnover estimates for E. rivulatus suggest this species is an important conduit of energy within the isolated patch reef habitat where it is typically found, while Ps. fuscus and Pa. clathrata channel smaller amounts of energy from specific habitats in the Ningaloo lagoon. Apparent differences in habitat, diet and turnover rates of the three species examined provide an insight into the different roles these species play in coral reef food webs and suggest that life-history traits allow for variability in the local and spatial contribution of these species at Ningaloo Reef. Moreover, calculating turnover rates of a broader suite of fish species from a range of trophic groups will help better define the role of fishes in coral reef trophic dynamics.

  17. Coral Reef Biological Criteria

    EPA Science Inventory

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

  18. Rivers, runoff, and reefs

    USGS Publications Warehouse

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

    2003-01-01

    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.

  19. 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...

  20. Miocene reef facies of Pelagian Block, central Mediterranean

    SciTech Connect

    Pedley, H.M.

    1988-01-01

    Miocene reefs outcrop in the Maltese Islands, southeastern Sicily, and the pelagian island of Lampedusa. Several rapid eustatic sea level fluctuations affected these late Tortonian-early Messinian build-ups; normal salinities appear to have been maintained during these events. Substrate, topography, sedimentation rate, and tectonic/eustatic events controlled reef development, which can be grouped into three settings: The most stable situation, the oldest Maltese and southeastern Sicilian reefs, has a ramp profile 15-30 km wide. The outermost zone consists of a broad belt of the large benthic foraminifer Heterostegina (compared with the underyling Oligocene beds rich in Lepidocyclina). Coralline algal carbonates, commonly rhodolitic, form a broad biostromal up-ramp association, kilometers in width, which commonly extends into the shallowest parts of the shelf. Scattered across the shallower ramp areas, in water depths generally less than 10 m, are coral-algal patch reefs, rarely larger than 20-50 m in diameter, commonly with truncated tops, and dominated by crustose coralline algae and the corals Porites and Tarbellastraea.

  1. Different dispersal abilities allow reef fish to coexist.

    PubMed

    Bode, Michael; Bode, Lance; Armsworth, Paul R

    2011-09-27

    The coexistence of multiple species on a smaller number of limiting resources is an enduring ecological paradox. The mechanisms that maintain such biodiversity are of great interest to ecology and of central importance to conservation. We describe and prove a unique and robust mechanism for coexistence: Species that differ only in their dispersal abilities can coexist, if habitat patches are distributed at irregular distances. This mechanism is straightforward and ecologically intuitive, but can nevertheless create complex coexistence patterns that are robust to substantial environmental stochasticity. The Great Barrier Reef (GBR) is noted for its diversity of reef fish species and its complex arrangement of reef habitat. We demonstrate that this mechanism can allow fish species with different pelagic larval durations to stably coexist in the GBR. Further, coexisting species on the GBR often dominate different subregions, defined primarily by cross-shelf position. Interspecific differences in dispersal ability generate similar coexistence patterns when dispersal is influenced by larval behavior and variable oceanographic conditions. Many marine and terrestrial ecosystems are characterized by patchy habitat distributions and contain coexisting species that have different dispersal abilities. This coexistence mechanism is therefore likely to have ecological relevance beyond reef fish.

  2. Miocene reefs in western Mediterranean

    SciTech Connect

    Esteban, M.

    1988-01-01

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

  3. Seismic stratigraphy, sediments, and basin history of Tonga forearc basin, late Eocene to Pleistocene

    SciTech Connect

    Herzer, R.H.; Ballance, P.F.; Cole, J.W.; Exon, N.F.; Stevenson, A.J.; Tappin, D.

    1986-07-01

    Four seismic reflectors (A, B, C, V) define primarily unconformity-bounded sedimentary sequences. Basement (V) is a block-faulted surface, apparently of Eocene volcanics. Above this, an upper Eocene sequence (CV) mainly buries the fault topography, pinching out locally on fault-block and volcanic highs along the eastern side of the basin. This sequence includes volcaniclastics and, on paleohighs, shallow-water limestones. Overlying this is a widespread upper Oligocene-lower Miocene sequence (BC), which also thins and pinches out locally against the high eastern side of the basin. Volcaniclastics are common, but limestones may occur locally. Seismic interpretations indicate little faulting during deposition of this sequence; prominent lenticular bodies could be either sills or reefs. Sequence AB, of middle and late Miocene to early Pliocene age, is composed of volcanopelagics deposited when the Lau arc was active, adjacent to the Tonga platform. No volcanic centers are seen in this sequence in the forearc, but shallow intrusions are common. Major tensional faulting developed toward the end of this depositional cycle. The uppermost sequence (SBA), of late Pliocene to Pleistocene age, also comprises volcanopelagic sediments. The volcanics are derived from the nearby Tofua arc, which developed with the opening of the Lau back-arc basin. Doming and tensional faulting in the late Pliocene-Pleistocene raised parts of the Tonga forearc basin, allowing wide reef platforms to develop.

  4. Frontier seismic geologic techniques and the exploration of the Miocene reefs in offshore Palawan, Philippines

    NASA Astrophysics Data System (ADS)

    Biswas, Buddhadeb

    An 88 km grid of Seislog sections (synthetic sonic log traces) was used to supplement the conventional seismic interpretation to assess the hydrocarbon potential of Lower Miocene reefs of offshore Palawan, Philippines. The porosity distribution in the zone of interest as well as the oil-water contact in and around the Tara and Libro patch reefs were mapped. The structural mapping was also fine tuned, including mapping of faults with small displacements. The paradox of pooling of hydrocarbons is evident in the maximum fill in the front line of traps near the shelf-slope break that are in the lowest structural position. Progressively dwindling amounts of fill in the structurally higher updip basin positions are interpreted to be due to the migration of hydrocarbons from the hydrocarbon kitchen in the Palawan Trough. The front line of traps had the benefit of maximum fill, the traps at the rear only of residual fill that spilled past the frontal traps. Three play types corresponding to the front line of traps, the rear line of traps and the most remote line of traps have been identified. Frontal reefs are considered to have the highest hydrocarbon potential. Diminishing hydrocarbon potential is inferred for closures in the updip direction. A thorough screening of all available seismic control for mapping all the patch reefs that might compensate for their dimensions by their numbers as well as for detecting possible pinnacle reefs in the downdip basin position has been suggested.

  5. Coral reef grazer-benthos dynamics complicated by invasive algae in a small marine reserve

    PubMed Central

    Stamoulis, Kostantinos A.; Friedlander, Alan M.; Meyer, Carl G.; Fernandez-Silva, Iria; Toonen, Robert J.

    2017-01-01

    Blooms of alien invasive marine algae have become common, greatly altering the health and stability of nearshore marine ecosystems. Concurrently, herbivorous fishes have been severely overfished in many locations worldwide, contributing to increases in macroalgal cover. We used a multi-pronged, interdisciplinary approach to test if higher biomass of herbivorous fishes inside a no-take marine reserve makes this area more resistant to invasive algal overgrowth. Over a two year time period, we (1) compared fish biomass and algal cover between two fished and one unfished patch reef in Hawai’i, (2) used acoustic telemetry to determine fidelity of herbivorous fishes to the unfished reef, and (3) used metabarcoding and next-generation sequencing to determine diet composition of herbivorous fishes. Herbivore fish biomass was significantly higher in the marine reserve compared to adjacent fished reefs, whereas invasive algal cover differed by species. Herbivorous fish movements were largely confined to the unfished patch reef where they were captured. Diet analysis indicated that the consumption of invasive algae varied among fish species, with a high prevalence of comparatively rare native algal species. Together these findings demonstrate that the contribution of herbivores to coral reef resilience, via resistance to invasive algae invasion, is complex and species-specific. PMID:28276458

  6. Coral reef grazer-benthos dynamics complicated by invasive algae in a small marine reserve.

    PubMed

    Stamoulis, Kostantinos A; Friedlander, Alan M; Meyer, Carl G; Fernandez-Silva, Iria; Toonen, Robert J

    2017-03-09

    Blooms of alien invasive marine algae have become common, greatly altering the health and stability of nearshore marine ecosystems. Concurrently, herbivorous fishes have been severely overfished in many locations worldwide, contributing to increases in macroalgal cover. We used a multi-pronged, interdisciplinary approach to test if higher biomass of herbivorous fishes inside a no-take marine reserve makes this area more resistant to invasive algal overgrowth. Over a two year time period, we (1) compared fish biomass and algal cover between two fished and one unfished patch reef in Hawai'i, (2) used acoustic telemetry to determine fidelity of herbivorous fishes to the unfished reef, and (3) used metabarcoding and next-generation sequencing to determine diet composition of herbivorous fishes. Herbivore fish biomass was significantly higher in the marine reserve compared to adjacent fished reefs, whereas invasive algal cover differed by species. Herbivorous fish movements were largely confined to the unfished patch reef where they were captured. Diet analysis indicated that the consumption of invasive algae varied among fish species, with a high prevalence of comparatively rare native algal species. Together these findings demonstrate that the contribution of herbivores to coral reef resilience, via resistance to invasive algae invasion, is complex and species-specific.

  7. Multiple outlier-reef trends off a carbonate platform: A new type of windward margin (south Florida)

    SciTech Connect

    Lidz, B.H.; Shinn, E.A. ); Hine, A.C. )

    1991-03-01

    A new set of sidescan-sonar imagery and high-resolution seismic-reflection profiles provides enhanced definition of a system of multiple outlier-reef tracts off the lower Florida Keys. The reefs occur approximately 0.5 to 1.5 km seaward of the south Florida bank margin. The system comprises a massive, outer, main reef tract of high (28 m) unburied relief that parallels the margin, and at least two narrower, discontinuous reef tracts of lower relief between the main tract and the shallow platform-margin reefs. The outer tract is approximately 0.5 to 1 km wide and extends a distance of about 57 km. A single pass divides the outer tract into two main reefs. This outlier-reef system developed in response to sea-level fluctuations and apparently formed on antecedent, low-gradient to flat offbank surfaces, which are interpreted to be Pleistocene beaches that formed terrace-like features now in 30 to 40 m of water. Radiocarbon dates of a coral core from the outer tract confirm a pre-Holocene age. The multiple outlier-reef system represents a new type of windward margin that presents a significant, unique mechanism for progradation of carbonate platforms during periods of sea-level fluctuation. Infilling of the backreef basins would create new, submerged, terraced headlands and would extend or 'step' the platform seaward for hundreds of meters. Subsequent outlier-reef development would be dependent upon sea-level fluctuations and would result in laterally accumulating sequences. Implications are that similar subsurface outlier-reef systems may exist and that these systems could become clearly defined hydrocarbon reservoirs.

  8. 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...

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

    PubMed

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

    2014-09-01

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

  10. Bleaching drives collapse in reef carbonate budgets and reef growth potential on southern Maldives reefs

    PubMed Central

    Perry, C. T.; Morgan, K. M.

    2017-01-01

    Sea-surface temperature (SST) warming events, which are projected to increase in frequency and intensity with climate change, represent major threats to coral reefs. How these events impact reef carbonate budgets, and thus the capacity of reefs to sustain vertical growth under rising sea levels, remains poorly quantified. Here we quantify the magnitude of changes that followed the ENSO-induced SST warming that affected the Indian Ocean region in mid-2016. Resultant coral bleaching caused an average 75% reduction in coral cover (present mean 6.2%). Most critically we report major declines in shallow fore-reef carbonate budgets, these shifting from strongly net positive (mean 5.92 G, where G = kg CaCO3 m−2 yr−1) to strongly net negative (mean −2.96 G). These changes have driven major reductions in reef growth potential, which have declined from an average 4.2 to −0.4 mm yr−1. Thus these shallow fore-reef habitats are now in a phase of net erosion. Based on past bleaching recovery trajectories, and predicted increases in bleaching frequency, we predict a prolonged period of suppressed budget and reef growth states. This will limit reef capacity to track IPCC projections of sea-level rise, thus limiting the natural breakwater capacity of these reefs and threatening reef island stability. PMID:28084450

  11. Bleaching drives collapse in reef carbonate budgets and reef growth potential on southern Maldives reefs.

    PubMed

    Perry, C T; Morgan, K M

    2017-01-13

    Sea-surface temperature (SST) warming events, which are projected to increase in frequency and intensity with climate change, represent major threats to coral reefs. How these events impact reef carbonate budgets, and thus the capacity of reefs to sustain vertical growth under rising sea levels, remains poorly quantified. Here we quantify the magnitude of changes that followed the ENSO-induced SST warming that affected the Indian Ocean region in mid-2016. Resultant coral bleaching caused an average 75% reduction in coral cover (present mean 6.2%). Most critically we report major declines in shallow fore-reef carbonate budgets, these shifting from strongly net positive (mean 5.92 G, where G = kg CaCO3 m(-2) yr(-1)) to strongly net negative (mean -2.96 G). These changes have driven major reductions in reef growth potential, which have declined from an average 4.2 to -0.4 mm yr(-1). Thus these shallow fore-reef habitats are now in a phase of net erosion. Based on past bleaching recovery trajectories, and predicted increases in bleaching frequency, we predict a prolonged period of suppressed budget and reef growth states. This will limit reef capacity to track IPCC projections of sea-level rise, thus limiting the natural breakwater capacity of these reefs and threatening reef island stability.

  12. Bleaching drives collapse in reef carbonate budgets and reef growth potential on southern Maldives reefs

    NASA Astrophysics Data System (ADS)

    Perry, C. T.; Morgan, K. M.

    2017-01-01

    Sea-surface temperature (SST) warming events, which are projected to increase in frequency and intensity with climate change, represent major threats to coral reefs. How these events impact reef carbonate budgets, and thus the capacity of reefs to sustain vertical growth under rising sea levels, remains poorly quantified. Here we quantify the magnitude of changes that followed the ENSO-induced SST warming that affected the Indian Ocean region in mid-2016. Resultant coral bleaching caused an average 75% reduction in coral cover (present mean 6.2%). Most critically we report major declines in shallow fore-reef carbonate budgets, these shifting from strongly net positive (mean 5.92 G, where G = kg CaCO3 m‑2 yr‑1) to strongly net negative (mean ‑2.96 G). These changes have driven major reductions in reef growth potential, which have declined from an average 4.2 to ‑0.4 mm yr‑1. Thus these shallow fore-reef habitats are now in a phase of net erosion. Based on past bleaching recovery trajectories, and predicted increases in bleaching frequency, we predict a prolonged period of suppressed budget and reef growth states. This will limit reef capacity to track IPCC projections of sea-level rise, thus limiting the natural breakwater capacity of these reefs and threatening reef island stability.

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  14. Plio-pleistocene African climate

    SciTech Connect

    deMenocal, P.B.

    1995-10-06

    Marine records of African climate variability document a shift toward more arid conditions after 2.8 million years ago (Ma), evidently resulting from remote forcing by cold North Atlantic sea-surface temperatures associated with the onset of Northern Hemisphere glacial cycles. African climate before 2.8 Ma was regulated by low-latitude insolation forcing of monsoonal climate due to Earth orbital precession. Major steps in the evolution of African hominids and other vertebrates are coincident with shifts to more arid, open conditions near 2.8 Ma, 1.7 Ma, and 1.0 Ma, suggesting that some Pliocene (Plio)-Pleistocene speciation events may have been climatically mediated. 65 refs., 6 figs.

  15. Plio-Pleistocene African Climate

    NASA Astrophysics Data System (ADS)

    Demenocal, Peter B.

    1995-10-01

    Marine records of African climate variability document a shift toward more arid conditions after 2.8 million years ago (Ma), evidently resulting from remote forcing by cold North Atlantic sea-surface temperatures associated with the onset of Northern Hemisphere glacial cycles. African climate before 2.8 Ma was regulated by low-latitude insolation forcing of monsoonal climate due to Earth orbital precession. Major steps in the evolution of African hominids and other vertebrates are coincident with shifts to more arid, open conditions near 2.8 Ma, 1.7 Ma, and 1.0 Ma, suggesting that some Pliocene (Plio)-Pleistocene speciation events may have been climatically mediated.

  16. Hydraulic exchange between a coral reef and surface sea water

    SciTech Connect

    Tribble, G.W.; Sansone, F.J.; Li, Yuan-Hui

    1992-10-01

    Hydraulic exchange between overlying sea water and the internal structure of a patch reef in Kaneohe Bay, Oahu, Hawaii, was studied with an array of wells, 1, 2, and 4 m deep. Two natural chemical tracers, radon, and salinity, were used to calculate the exchange rate between surface sea water and reef interstitial waters. Dissolved radon concentrations are substantially higher in interstitial waters than is surface water. The degree of radon enrichment is quantitatively related to the time elapsed since interstitial water had equilibrated with the atmosphere. Residence time estimates are 1-40 days, with deeper wells having slower exchange. The average residence time for 1-m-deep wells was 2.1 days. A rainstorm-induced dilution of the salinity of Kaneohe Bay provides the second tracer. Samples of surface and reef interstitial waters following this salinity perturbation are used to calculate an average residence time of 2.6 days at a depth of 1 m and 42 days at a depth of 2 m. Three types of physical forces thought to cause exchange between surface and interstitial water are considered by measurement of the forcing functions and reef permeability. Hydraulic conductivities are about 50 m/d, with lower values near the seaward side of the reef. Most exchange seems to be caused by high-frequency, wave-driven oscillatory pumping and by unidirectional hydraulic head gradients (of uncertain origin) that are stable for at least 3-4 days. Wave-driven mixing is probably more important shallower in the reef, whereas head-driven flow may dominate deeper in the reef. Tidal pumping does not seem to contribute to exchange. All methods indicate that exchange in the upper part of Checker Reef is primarily through vertical exchange. The best estimate for the residence time of water at a depth of 1 m is 2 days. Water at depths of 204 m probably has a residence time of weeks to months. 49 refs., 8 figs., 6 tabs.

  17. Wave transformation over coral reefs

    NASA Astrophysics Data System (ADS)

    Young, Ian R.

    1989-07-01

    Ocean wave attenuation on coral reefs is discussed using data obtained from a preliminary field experiment and from the Seasat altimeter. Marked attenuation of the waves is observed, the rate being consistent with existing theories of bottom friction and wave breaking decay. In addition, there is a significant broadening of the spectrum during propagation across reefs. Three-dimensional effects, such as refraction and defraction, can also lead to substantial wave height reduction for significant distances adjacent to coral reefs. As a result, a matrix of such reefs provides significantly more wave attenuation than may initially be expected.

  18. Digital Reef Rugosity Estimates Coral Reef Habitat Complexity

    PubMed Central

    Dustan, Phillip; Doherty, Orla; Pardede, Shinta

    2013-01-01

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

  19. Digital reef rugosity estimates coral reef habitat complexity.

    PubMed

    Dustan, Phillip; Doherty, Orla; Pardede, Shinta

    2013-01-01

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

  20. Holocene core logs and site methods for modern reef and head-coral cores - Dry Tortugas National Park, Florida

    USGS Publications Warehouse

    Hickey, Todd D.; Reich, Christopher D.; DeLong, Kristine L.; Poore, Richard Z.; Brock, John C.

    2013-01-01

    The Dry Tortugas are a series of islands, banks, and channels on a carbonate platform off the west end of the Florida Keys. Antecedent topography of the Dry Tortugas reflects carbonate accumulations of the last interglacial (marine isotope substage 5e, ~ 125,000 years ago, ka) when sea level was ~ 6 to 7 meters (m) higher than present (Schrag and others, 2002). The substage 5e surface was subsequently lithified and modified during subaerial exposure associated with lower sea level from ~ 120 ka to 8 ka. The lithified late Pleistocene carbonates are known as the Key Largo Limestone, a coral reef (Hoffmeister and Multer, 1964; Multer and others, 2002), and the Miami Limestone, a tidal-bar oolite (Sanford, 1909; Hoffmeister, 1974). The Holocene and modern sediments and reefs of the Dry Tortugas then accreted during the rise of sea level associated with the end of the last glacial and the start of the current interglacial (marine isotope Stage 1). With the exception of a half dozen or so islands, the Dry Tortugas region has been submerged for approximately 8,000 years, allowing conditions suitable for coral reef formation once again. The Holocene reef accumulation varies in thickness due to the antecedent topography. The reefs are composed of massive head corals such as species of Montastraea, Siderastrea, and Diploria (Swart and others, 1996; Cohen and McConnaughey, 2003) and rest atop the Pleistocene Key Largo Limestone high (Shinn and others, 1977). The coral reefs within the Dry Tortugas represent a windward reef margin relative to dominant wind and wave energies (Hine and Mullins, 1983; Mallinson and others, 1997; Mallinson and others, 2003).

  1. Modelling reef zonation in the Greater St Lucia Wetland Park, South Africa

    NASA Astrophysics Data System (ADS)

    Schleyer, Michael H.; Celliers, Louis

    2005-05-01

    East Africa has a rich coral fauna that extends to Maputaland in KwaZulu-Natal, South Africa. At this latitude, considered high and marginal for coral distribution and development, they form a veneer on limited, late Pleistocene reefs rather than forming the accretive, aragonite structures known as coral reefs. It is thus more appropriate to refer to them in this region as coral communities, the environment being rendered marginal for their development by reduced temperatures, light and aragonite saturation state. Subsequent to their discovery, the reefs were afforded protection within two Marine Protected Areas (the St Lucia and Maputaland Marine Reserves). They are found primarily within three reef complexes, with only the central complex being readily accessible to the public for ecotourism at present. With the creation of the Greater St Lucia Wetland Park, a World Heritage Site, and the expectation of an accompanying increase in ecotourism, the status quo seems set to change. The reefs are thus the current focus of a modelling initiative to provide decision support in their management. This paper examines the unique nature of the South African communities, their vulnerability and importance in the regional and global context, and, using representative data from the model, how an anticipated increase in their use could affect their sustainability. The case for scientifically based zonation for their use is presented.

  2. Smart patch piezoceramic actuator issues

    NASA Technical Reports Server (NTRS)

    Griffin, Steven F.; Denoyer, Keith K.; Yost, Brad

    1993-01-01

    The Phillips Laboratory is undertaking the challenge of finding new and innovative ways to integrate sensing, actuation, and the supporting control and power electronics into a compact self-contained unit to provide vibration suppression for a host structure. This self-contained unit is commonly referred to as a smart patch. The interfaces to the smart patch will be limited to standard spacecraft power and possibly a communications line. The effort to develop a smart patch involves both contractual and inhouse programs which are currently focused on miniaturization of the electronics associated with vibrational control using piezoceramic sensors and actuators. This paper is comprised of two distinct parts. The first part examines issues associated with bonding piezoceramic actuators to a host structure. Experimental data from several specimens with varying flexural stiffness are compared to predictions from two piezoelectric/substructure coupling models, the Blocked Force Model and the Uniform Strain Model with Perfect Bonding. The second part of the paper highlights a demonstration article smart patch created using the insights gained from inhouse efforts at the Phillips Laboratory. This demonstration article has self contained electronics on the same order of size as the actuator powered by a voltage differential of approximately 32 volts. This voltage is provided by four rechargeable 8 volt batteries.

  3. Environmental Influences on Pleistocene Hominid Dental Evolution

    ERIC Educational Resources Information Center

    Greene, David L.

    1970-01-01

    Considers natural and cultural environmental factors likely to have been responsible for reduction in size of hominid teeth and simplification of their morphology during the Pleistocene. Cites fossil evidence and postulates selective mechanisms. (EB)

  4. Taphonomy of coral reefs from Southern Lagoon of Belize

    SciTech Connect

    Westphall, M.J.; Ginsburg, R.N.

    1985-02-01

    The Southern Lagoon of the Belize barrier complex, an area of some 600 km/sup 2/, contains a tremendous number of lagoon reefs, which range in size from patches several meters across to rhomboidal-shaped structures several kilometers in their long dimension. These lagoon reefs are remarkable because they have Holocene sediment accumulations in excess of 13 m consisting almost entirely of coral debris and lime mud and sand, and rise up to 30 m above the surrounding lagoon floor with steeply sloping sides (50-80/sup 0/), yet are totally uncemented. The reef-building biota and their corresponding deposits were studied at a representative reef, the rhomboidal complex of Channel Cay. As with many of the reefs in this area, the steeply sloping flanks of Channel Cay are covered mainly by the branched staghorn coral Acropora cervicornis and ribbonlike and platy growth of Agaricia spp. The living corals are not cemented to the substrate, but are merely intergrown. Fragmented pieces of corals accumulate with an open framework below the living community; this open framework is subsequently infilled by lime muds and sands produced mainly from bioerosion. Results from probing and coring suggest that the bafflestone fabric of coral debris and sediment extends at least 13 m into the subsurface. Radiocarbon-age estimates indicate these impressive piles of coral rubble and sediment have accumulated in the past 9000 yr (giving a minimum accumulation rate of 1.4 m/1000 yr) and illustrate the potential for significant carbonate buildups without the need for early lithification.

  5. Reef and nonreef aquifers - A comparison of hydrogeology and geochemistry, northwestern Indiana

    USGS Publications Warehouse

    Schnoebelen, D.J.; Krothe, N.C.

    1999-01-01

    The principal bedrock aquifer system across much of Indiana consists of carbonate rocks of Silurian and Devonian age. The Silurian-Devonian aquifer system is used extensively for irrigation in northwestern Indiana and is approximately 170 m thick. Reef and nonreef carbonate aquifers in northwestern Indiana were assessed using hydrogeology (lithology, geophysical logs, aquifer tests) and geochemistry (major ions and stable isotopes). The study showed differences in water quantity and quality between the reef and nonreef aquifers. The reef aquifer had few shales, abundant fossiliferous material (up to 100 m thick), and high porosities (10 to 15%). The nonreef aquifer had abundant shales, less fossiliferous material (a few meters thick), and low porosities. Total transmissivities at the reef sites were 697 m2/d, (meters squared per day) and 4831 m2/d, compared to 46 m2/d at the nonreef site. Flowpaths in the nonreef aquifer were associated with fractures and poorly connected moldic porosity with larger fractures and better connected vuggy porosity in the reef aquifer. Water chemistry data for the nonreef aquifer showed mean concentrations of sodium (235 mg/L [milligrams per liter]), sulfate (160 mg/L), sulfide (13 mg/L), fluoride (2.7 mg/L), and dissolved solids (635 mg/L) approximately two to five times larger when compared to mean concentrations in the reef aquifer. Ground water at the nonreef site was classified as a sodium-bicarbonate type while that at the reef sites was calcium-magnesium bicarbonate. The oxygen/deuterium isotope data indicates recharge from modern precipitation and not Pleistocene-age recharge.The principal bedrock aquifer system across much of Indiana consists of carbonate rocks of Silurian and Devonian age. The Silurian-Devonian aquifer system is used extensively for irrigation in northwestern Indiana and is approximately 170 m thick. Reef and nonreef carbonate aquifers in northwestern Indiana were assessed using hydrogeology (lithology

  6. Monitoring the coral disease, plague type II, on coral reefs in St. John, U.S. Virgin Islands

    USGS Publications Warehouse

    Miller, J.; Rogers, C.; Waara, R.

    2003-01-01

    In July 1997, conspicuous white patches of necrotic tissue and bare skeleton began to appear on scleractinian corals in several bays around St. John, US Virgin Islands. Analysis of diseased coral tissue from five different species confirmed the presence of a Sphingomonas-like bacterium, the pathogen for plague type II. To date, 14 species of hard corals have been affected by plague type II around St. John. This disease was monitored at Haulover and Tektite Reefs at depths of 7-12 meters. The study site at Tektite Reef has >50% cover by scleractinian corals with 90% of hard corals being composed of Montastraea annular is. Monthly surveys at Tektite Reef from December 1997 to May 2001 documented new incidence of disease (bare white patches of skeleton) every month with associated loss of living coral and 90.5% of all disease patches occurred on M. annularis. The frequency of disease within transects ranged from 3 to 58%, and the area of disease patches ranged from 0.25 to 9000 cm2. The average percent cover by the disease within 1 m2 ranged from 0.01% (?? 0.04 SD) to 1.74% (?? 9.08 SD). Photo-monitoring of 28 diseased corals of 9 species begun in September 1997 at Haulover Reef revealed no recovery of diseased portions with all necrotic tissue being overgrown rapidly by turf algae, usually within less than one month. Most coral colonies suffered partial mortality. Very limited recruitment (e.g., of Agaricia spp., Favia spp. and sponges) has been noted on the diseased areas. This coral disease has the potential to cause more loss of live coral on St. John reefs than any other stress to date because it targets the dominant reef building species, M. annularis.

  7. Presence of cleaner wrasse increases the recruitment of damselfishes to coral reefs.

    PubMed

    Sun, Derek; Cheney, Karen L; Werminghausen, Johanna; Meekan, Mark G; McCormick, Mark I; Cribb, Thomas H; Grutter, Alexandra S

    2015-08-01

    Mutualisms affect the biodiversity, distribution and abundance of biological communities. However, ecological processes that drive mutualism-related shifts in population structure are often unclear and must be examined to elucidate how complex, multi-species mutualistic networks are formed and structured. In this study, we investigated how the presence of key marine mutualistic partners can drive the organisation of local communities on coral reefs. The cleaner wrasse, Labroides dimidiatus, removes ectoparasites and reduces stress hormones for multiple reef fish species, and their presence on coral reefs increases fish abundance and diversity. Such changes in population structure could be driven by increased recruitment of larval fish at settlement, or by post-settlement processes such as modified levels of migration or predation. We conducted a controlled field experiment to examine the effect of cleaners on recruitment processes of a common group of reef fishes, and showed that small patch reefs (61-285 m(2)) with cleaner wrasse had higher abundances of damselfish recruits than reefs from which cleaner wrasse had been removed over a 12-year period. However, the presence of cleaner wrasse did not affect species diversity of damselfish recruits. Our study provides evidence of the ecological processes that underpin changes in local population structure in the presence of a key mutualistic partner.

  8. Effects of territorial damselfish on an algal-dominated coastal coral reef

    NASA Astrophysics Data System (ADS)

    Ceccarelli, Daniela M.; Jones, Geoffrey P.; McCook, Laurence J.

    2005-12-01

    Territorial damselfish are important herbivores on coral reefs because they can occupy a large proportion of the substratum and modify the benthic community to promote the cover of food algae. However, on coastal coral reefs damselfish occupy habitats that are often dominated by unpalatable macroalgae. The aim of this study was to examine whether damselfish can maintain distinctive algal assemblages on a coastal reef that is seasonally dominated by Sargassum (Magnetic Island, Great Barrier Reef). Here, three abundant species ( Pomacentrus tripunctatus, P. wardi and Stegastes apicalis) occupied up to 60% of the reef substrata. All three species promoted the abundance of food algae in their territories. The magnitudes of the effects varied among reef zones, but patterns were relatively stable over time. Damselfish appear to readily co-exist with large unpalatable macroalgae as they can use it as a substratum for promoting the growth of palatable epiphytes. Damselfish territories represent patches of increased epiphyte load on macroalgae, decreased sediment cover, and enhanced cover of palatable algal turf.

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

    PubMed

    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

    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.

  10. Coral reefs and carbon dioxide

    SciTech Connect

    Buddemeier, R.W.

    1996-03-01

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

  11. Faunal turnover in Neogene to Recent Caribbean reef corals and region environmental change

    SciTech Connect

    Budd, A.F. . Geology Dept.); Johnson, K.G. . Palaeontology Dept.); Stemann, T.A. . Geologisches Inst.)

    1993-03-01

    Quantitative analyses of species richness and species extinction and origination rates in the Neogene to Recent Caribbean reef coral fauna show that a major episode of turnover occurred during middle to late Pliocene time (4--1 Ma). The data for the authors analyses consist of a new compilation of occurrences of 175 species and 49 genera in reef sequences in the Dominican Republic and Costa Rica and in 21 scattered sites ranging in age from 22 Ma to present. The results show that: (1) during turnover, more than 75% of all species living between 6--4 Ma (n = 82) became extinct; (2) during turnover, extinction and origination rates were equally and simultaneously high, and a relatively constant number of species was maintained in the fauna; (3) the taxonomic composition of Caribbean reefs remained relatively constant before (10--4 Ma) and after (1--0 Ma) turnover. Turnover therefore preceded the high frequency sea level oscillations of late Pleistocene time, and appears related to long-term, unidirectional changes in climate and/or ocean circulation across the Caribbean region in association with closure of the Isthmus of Panama. The observed correspondence between high origination and extinction rates indicates that the same environmental factors may have been associated with increases in both rates, and that local habitat differentiation and fragmentation may have been involved. Stability persisted in the region despite the severe environmental stresses associated with Pleistocene climate change.

  12. Confronting the coral reef crisis

    NASA Astrophysics Data System (ADS)

    Bellwood, D. R.; Hughes, T. P.; Folke, C.; Nyström, M.

    2004-06-01

    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 and ecological surprises. Here we review the ecological roles of critical functional groups (for both corals and reef fishes) that are fundamental to understanding resilience and avoiding phase shifts from coral dominance to less desirable, degraded ecosystems. We identify striking biogeographic differences in the species richness and composition of functional groups, which highlight the vulnerability of Caribbean reef ecosystems. These findings have profound implications for restoration of degraded reefs, management of fisheries, and the focus on marine protected areas and biodiversity hotspots as priorities for conservation.

  13. Pleistocene changes in the fauna and flora of South america.

    PubMed

    Vuilleumier, B S

    1971-08-27

    forest elements (40) now justify the conclusion that the floras and faunas of these areas were also greatly affected by Pleistocene climatic shifts. In the broad region of South America that lies within the tropics, a series of humid-arid cycles (Appendix, 6, 8-10) drastically and repeatedly altered vegetation patterns during the Quaternary. Both montane and lowland rainforests were fragmented during dry periods and were able to reexpand during humid phases. Speciation of forest elements was initiated-and sometimes completed-in isolated patches of the fragmented forest. Secondary contact, with hybridization or reunition of populations that did not become reproductively isolated, occurred in periods of reexpansion. These biological data, combined with supportive geological evidence (Appendix, 1-11), show that climatic events during the last million or so years have affected the biota of South America as much as the Pleistocene glacial changes affected the biotas of Eurasia and North America. Since most of South America lies within tropical latitudes, it is suggested here that part of the diversity of species in the tropical areas of this continent is due to two historical factors: the lack of wholesale elimination of species (compared with northern and high latitudes), and ample opportunity for speciation in successive periods of ecological isolation. The apparent paradox of the wealth of species in the "stable tropics" is partially explained by the fact that the tropics have probably been quite unstable, from the point of view of their biotas, during the Pleistocene and perhaps part of the Tertiary.

  14. 40 CFR 230.44 - Coral reefs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Coral reefs. 230.44 Section 230.44... Aquatic Sites § 230.44 Coral reefs. (a) Coral reefs consist of the skeletal deposit, usually of calcareous... organisms present in growing portions of the reef. (b) Possible loss of values: The discharge of dredged...

  15. 40 CFR 230.44 - Coral reefs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Coral reefs. 230.44 Section 230.44... Aquatic Sites § 230.44 Coral reefs. (a) Coral reefs consist of the skeletal deposit, usually of calcareous... organisms present in growing portions of the reef. (b) Possible loss of values: The discharge of dredged...

  16. 40 CFR 230.44 - Coral reefs.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Coral reefs. 230.44 Section 230.44... Aquatic Sites § 230.44 Coral reefs. (a) Coral reefs consist of the skeletal deposit, usually of calcareous... organisms present in growing portions of the reef. (b) Possible loss of values: The discharge of dredged...

  17. 40 CFR 230.44 - Coral reefs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Coral reefs. 230.44 Section 230.44... Aquatic Sites § 230.44 Coral reefs. (a) Coral reefs consist of the skeletal deposit, usually of calcareous... organisms present in growing portions of the reef. (b) Possible loss of values: The discharge of dredged...

  18. High-latitude steppe vegetation and the mineral nutrition of Pleistocene herbivores

    NASA Astrophysics Data System (ADS)

    Davydov, S. P.; Davydova, A.; Makarevich, R.; Loranty, M. M.; Boeskorov, G.

    2014-12-01

    High-latitude steppes were widespread and zonal in the Late Pleistocene and formed a landscape basis for the Mammoth Biome. Now the patches of these steppes survived on steep slopes under southern aspects. These steppes serve as unique information sources about the Late Pleistocene "Mammoth" steppe. Numerous data obtained by palynological, carpological, and DNA analysis of plant remains from feces and stomach contents of Pleistocene herbivore mummies, as well as from buried soils and enclosing deposits show that they are similar to modern steppe plant assemblage in taxa composition. Plant's nutrient concentrations are of fundamental importance across Pleistocene grass-rich ecosystems because of their role in the support of large herbivores. The average weight of an adult mammoth skeleton (about 0.5 tons) and of a woolly rhinoceros (about 0.2 tons) clearly suggests this. Detailed studies on fossil bone remains showed mineral deficiency in large Pleistocene herbivores. A three-year study of ash and mineral contents of two types of relict steppe vegetation at the Kolyma Lowland, Arctic Siberia has been carried out. Nowadays refugia of similar vegetation are located not far (1 - 15km) from the Yedoma permafrost outcrops were abundant fossil remains are found. Dominant species of the steppe vegetation were sampled. Preliminary studies indicate that the ash-content varied 1.5-2 times in speceies of steppe herbs. The Ca, P, Mg, K element contents was higher for most steppe species than in the local herbaceous vegetation, especially in Ca and P. One of the most important elements of the mineral nutrition, the phosphorus, was always found in higher concentrations in the steppe vegetation than in plants of recently dominant landscapes of the study area. It should be noted that the mineral nutrient content of the modern steppe vegetation of Siberian Arctic is comparable to that of the recent zonal steppe of Transbaikal Region. This study supports the hypothesis that

  19. Comparison of outcropping and buried reefs in Middle Devonian Winnipegosis Formation, Manitoba and Saskatchewan

    SciTech Connect

    Kent, D.M.; McCabe, H.R.

    1988-07-01

    In 1986, Winnipegosis reefs became prime exploration targets in the Williston basin, following the discovery of producible oil in the Home Tableland 8-22-2-9W2 well in southeast Saskatchewan. An understanding of the facies distribution in these reefs is difficult to acquire since few of them have been penetrated by more than one well. However, the exposed reefs in the Manitoba outcrop belt may be useful to develop facies models applicable to subsurface reefs. Winnipegosis reefs grew in an elongated northwest-trending basin extending from North Dakota to northwest Alberta. The basin was flanked on the west and southeast by an exposed hinterland to which was accreted a carbonate wedge of shallow shelf sediments. The reefs developed on a platform of normal marine carbonates underlying the entire basin. Differentiation into shelf and basin settings occurred after deposition of the platform sediments. The shelf sediments are predominantly lime mudstones and skeletal wackestones with local packstone and grainstone accumulations. The components of these lithologies include brachiopods, crinoids, solitary corals, ostracods, bryozoans, amphiporids, green algae, and peloids. Locally, there are stromatoporoid-coral patch reefs. The basinal deposits include starved-basin sediment consisting of kerogenous lime mudstones with intercalated reef-derived biogenic material, overlain by varvitic couplets of lime mudstone and kerogenous sediment. These pass upward into, and are interbedded with, layered anhydrites that are rich in black organic material either as an admixture to the anhydrite or as thin laminae. These sediments are interrupted by local buildups of lime mudstone, skeletal wackestone, packstone, and grainstone. The buildups range in height from 30 to 100 m above the starved-basin sediments. Those in southeast Saskatchewan are between approximately 30 and 60 m.

  20. Persistence and Change in Community Composition of Reef Corals through Present, Past, and Future Climates

    PubMed Central

    Edmunds, Peter J.; Adjeroud, Mehdi; Baskett, Marissa L.; Baums, Iliana B.; Budd, Ann F.; Carpenter, Robert C.; Fabina, Nicholas S.; Fan, Tung-Yung; Franklin, Erik C.; Gross, Kevin; Han, Xueying; Jacobson, Lianne; Klaus, James S.; McClanahan, Tim R.; O'Leary, Jennifer K.; van Oppen, Madeleine J. H.; Pochon, Xavier; Putnam, Hollie M.; Smith, Tyler B.; Stat, Michael; Sweatman, Hugh; van Woesik, Robert; Gates, Ruth D.

    2014-01-01

    The reduction in coral cover on many contemporary tropical reefs suggests a different set of coral community assemblages will dominate future reefs. To evaluate the capacity of reef corals to persist over various time scales, we examined coral community dynamics in contemporary, fossil, and simulated future coral reef ecosystems. Based on studies between 1987 and 2012 at two locations in the Caribbean, and between 1981 and 2013 at five locations in the Indo-Pacific, we show that many coral genera declined in abundance, some showed no change in abundance, and a few coral genera increased in abundance. Whether the abundance of a genus declined, increased, or was conserved, was independent of coral family. An analysis of fossil-reef communities in the Caribbean revealed changes in numerical dominance and relative abundances of coral genera, and demonstrated that neither dominance nor taxon was associated with persistence. As coral family was a poor predictor of performance on contemporary reefs, a trait-based, dynamic, multi-patch model was developed to explore the phenotypic basis of ecological performance in a warmer future. Sensitivity analyses revealed that upon exposure to thermal stress, thermal tolerance, growth rate, and longevity were the most important predictors of coral persistence. Together, our results underscore the high variation in the rates and direction of change in coral abundances on contemporary and fossil reefs. Given this variation, it remains possible that coral reefs will be populated by a subset of the present coral fauna in a future that is warmer than the recent past. PMID:25272143

  1. Tunable Patch Antennas Using Microelectromechanical Systems

    DTIC Science & Technology

    2011-05-11

    Tunable Microstrip Patch Antena Using RF MEMS Technology, IEEE Transactions on Antennas and Propagations, Vol. 55, Issue 4, April 2007, pp. 1193...capacitors co-fabricated in the same process. 15. SUBJECT TERMS Microstrip antennas, patch antennas, radio frequency microelectromechanical systems...resonant mode. Keywords: Microstrip antennas, patch antennas, radio frequency microelectromechanical systems, tunable circuits and devices 2

  2. OpenSSO Project Patches

    SciTech Connect

    NEBERGALL, CHRISTOPHER

    2009-06-08

    These are patches to Sun Microsystems open source OpenSSO project to fix various bugs and incorporate changes for Sandia and NNSA to use the product including fixes to improve OpenSSO's authentication and authorization abilities. These fixes will then by incorporated by Sun into their Sun Access Manager product, which is used by various DOE/NNSA plants and labs. Having Sun maintain these changes will relieve SNL and DOE from the cost of maintaining the changes themselves.

  3. Self-generated morphology in lagoon reefs.

    PubMed

    Blakeway, David; Hamblin, Michael G

    2015-01-01

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

  4. Self-generated morphology in lagoon reefs

    PubMed Central

    Hamblin, Michael G.

    2015-01-01

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

  5. Relative and combined effects of habitat and fishing on reef fish communities across a limited fishing gradient at Ningaloo.

    PubMed

    Wilson, Shaun K; Babcock, Russ C; Fisher, Rebecca; Holmes, Thomas H; Moore, James A Y; Thomson, Damian P

    2012-10-01

    Habitat degradation and fishing are major drivers of temporal and spatial changes in fish communities. The independent effects of these drivers are well documented, but the relative importance and interaction between fishing and habitat shifts is poorly understood, particularly in complex systems such as coral reefs. To assess the combined and relative effects of fishing and habitat we examined the composition of fish communities on patch reefs across a gradient of high to low structural complexity in fished and unfished areas of the Ningaloo Marine Park, Western Australia. Biomass and species richness of fish were positively correlated with structural complexity of reefs and negatively related to macroalgal cover. Total abundance of fish was also positively related to structural complexity, however this relationship was stronger on fished reefs than those where fishing is prohibited. The interaction between habitat condition and fishing pressure is primarily due to the high abundance of small bodied planktivorous fish on fished reefs. However, the influence of management zones on the abundance and biomass of predators and target species is small, implying spatial differences in fishing pressure are low and unlikely to be driving this interaction. Our results emphasise the importance of habitat in structuring reef fish communities on coral reefs especially when gradients in fishing pressure are low. The influence of fishing effort on this relationship may however become more important as fishing pressure increases.

  6. Mortality of shallow reef corals in the western Arabian Gulf following aerial exposure in winter

    NASA Astrophysics Data System (ADS)

    Fadlallah, Y. H.; Allen, K. W.; Estudillo, R. A.

    1995-05-01

    Aerial exposure of patch reef corals occurred in Tarut Bay, western Arabian Gulf, (Saudi Arabia) between December 1991 and May 1992, and coincided with extreme low spring tides (below the predicted lowest astronomical tide-LAT). Colonies of Acropora and Stylophora occurring at the highest levels on the tops of patch reef platforms were most affected by the low tides. Corals fully exposed to air suffered total mortality, whereas those not fully exposed suffered tissue damage to their upper parts. Exposure occurred during winter months when air and water temperatures are at their lowest in the gulf. Coupling of extremely low spring tides with wind-induced negative surges (below LAT) are not regular events but are not infrequent. Cold temperatures and exposure may act in concert to produce disproportionate mortalities of reef flat corals in the shallow coastal areas of eastern Saudi Arabia. It is highly unlikely that the Gulf War oil spill played any role in the observed damage to reef corals in the Gulf in 1992.

  7. Adaptive Avoidance of Reef Noise

    PubMed Central

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

    2011-01-01

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

  8. Adaptive avoidance of reef noise.

    PubMed

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

    2011-02-04

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

  9. Submerged Shelf Edge Features on Australia's Great Barrier Reef and Their Response to Quaternary Sea-Level Changes

    NASA Astrophysics Data System (ADS)

    Abbey, E. A.; Webster, J. M.; Beaman, R. J.

    2010-12-01

    Australia has the largest extant barrier reef system in the world, the Great Barrier Reef. As sensitive indicators of their environment, tropical coral reefs are also valuable repositories of climate and sea-level histories. As sea-levels oscillate, reefs wax and wane along shallow shelf margins. During rapid transgressions, many reefs are unable to keep up and become drowned. Submerged, or drowned, reefs can provide a wealth of information as to the nature and timing of local oceanic conditions, and are well-recognised for their value as relative sea-level indicators. The Great Barrier Reef may hold the largest repository of Pleistocene and Holocene climate and sea-level records in the world, in the form of submerged reefs. The current understanding of submerged reefs along the Great Barrier Reef shelf edge is based on widely-spaced singlebeam echosounder profiles and several small scale (3-8 km2) multibeam surveys. In spite of these earlier studies that hinted at the wide distribution of submerged reefs, no regional-scale work has been undertaken using high-resolution multibeam swath bathymetry. Here we investigate four widely-spaced sites (200 km) from depths of 45-130 m ranging in size up to 400 km2 along Australia’s north-east margin using high-resolution multibeam swath bathymetry and surficial dredge samples. The aims of this study include characterising the morphology, distribution and variety of features, as well as identifying the processes associated with their origin, to gain a better understanding of the history of the Great Barrier Reef and its response to Quaternary sea-level changes. The high-resolution (cell pixel size 5 m) dataset presented here has allowed an unprecedented view of the seabed topography. This highly detailed imagery reveals very subtle characteristics of features that can indicate their environmental setting: for example, submarine or subaerial, and constructional or erosional. Comprehensive mapping of each site has resulted in

  10. Invertebrates of the relict steppe ecosystems of Beringia, and the reconstruction of Pleistocene landscapes

    NASA Astrophysics Data System (ADS)

    Berman, Daniil; Alfimov, Arcady; Kuzmina, Svetlana

    2011-08-01

    Studies of invertebrates from steppe patches in the tundra and taiga zones of Beringia provide additional evidence that these areas could be relict steppes. A number of insect species common to both modern relict steppes and fossil Beringian insect faunal assemblages have been found. These provide important information on the moisture and temperature preferences of some of the surviving members of Pleistocene steppe-tundra insect communities. The most significant species of West Beringian insects are weevils in the genus Stephanocleonus (Coleoptera, Curculionidae), indicators of thermophytic steppe, and the pill beetle Morychus viridis (Coleoptera, Byrrhidae), the indicator of hemicryophytic steppe. The East Beringian invertebrate population of relict steppe is substantially different. Fossil evidence suggests that biotic exchange between the two parts of Beringia was limited during the Pleistocene; populations of steppe insects did not move across the Bering Land Bridge (BLB), while tundra species had more flexibility. The tundra environment reconstructed for the Pleistocene BLB should have facilitated amphi-beringian distributions for most tundra invertebrate species, but apparently only a few species achieved this.

  11. Miocene reef corals: A review

    SciTech Connect

    Frost, S.H.

    1988-01-01

    Tectonic blockage in the Middle East of westward-flowing Tethys surface circulation during the latest Oligocene led to creation in the earliest Miocene of endemic Mediterranean, Western Atlantic-Caribbean, and Indo-Pacific realms. A great reduction in reef coral diversity from 60-80 Oligocene species to 25-35 early Miocene species occurred in the Western Atlantic-Caribbean and Mediterranean areas accompanied by a decrease in reef growth. A slower and less drastic change apparently occurred in the Indo-Pacific area. Early Miocene reef corals of the Western Atlantic-Caribbean comprise a transition between the cosmopolitan Oligocene fauna and its endemic mid-Miocene to modern counterpart. Although early Miocene reefs were dominated by a Porites-Montastrea assemblage, eastward flow of Pacific circulation brought with it ''exotic'' corals such as Coscinaraea and Pseudocolumnastrea. Also, many cosmopolitan genera persisted from the Oligocene. During the middle to late Miocene, most of the species still living on Holocene reefs evolved. As the Mediterranean basin became more restricted, there was a slow decline in reef corals from 20 - 25 species in the Aquitainian to less than five species in the Messinian. Eustatic lowstand led to the extinction of reef-building corals in the late Messinian. In the Indo-Pacific, Neogene evolution of reef corals was conservative. Excluding the Acroporidae and Seriatoporidae, most Holocene framework species had evolved by the middle Miocene. Interplay between regional tectonics and eustatic sea level changes led to extensive development of middle to late Miocene pinnacle reefs over the southwestern Pacific.

  12. "Patch"ing up our tumor signaling knowledge.

    PubMed

    Atwood, Scott X; Whitson, Ramon J; Oro, Anthony E

    2013-05-01

    The tumor suppressor Patched1 (Ptch1) possesses well-described roles in regulating sonic hedgehog (SHH) signaling in the skin and preventing the formation of basal cell carcinomas (BCCs). In this issue, Kang et al. extend their previous work to show that a naturally occurring allele of Ptch1 found in FVB mice promotes early squamous cell carcinoma (SCC) growth without aberrant activation of the SHH pathway. The study reveals new roles for Ptch1 that lie at the nexus between BCC and SCC formation.

  13. NOAA's hydrolab conducts reef studies

    NASA Astrophysics Data System (ADS)

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

  14. Patching. Restitching business portfolios in dynamic markets.

    PubMed

    Eisenhardt, K M; Brown, S L

    1999-01-01

    In turbulent markets, businesses and opportunities are constantly falling out of alignment. New technologies and emerging markets create fresh opportunities. Converging markets produce more. And of course, some markets fade. In this landscape of continuous flux, it's more important to build corporate-level strategic processes that enable dynamic repositioning than it is to build any particular defensible position. That's why smart corporate strategists use patching, a process of mapping and remapping business units to create a shifting mix of highly focused, tightly aligned businesses that can respond to changing market opportunities. Patching is not just another name for reorganizing; patchers have a distinctive mindset. Traditional managers see structure as stable; patching managers believe structure is inherently temporary. Traditional managers set corporate strategy first, but patching managers keep the organization focused on the right set of business opportunities and let strategy emerge from individual businesses. Although the focus of patching is flexibility, the process itself follows a pattern. Patching changes are usually small in scale and made frequently. Patching should be done quickly; the emphasis is on getting the patch about right and fixing problems later. Patches should have a test drive before they're formalized but then be tightly scripted after they've been announced. And patching won't work without the right infrastructure: modular business units, fine-grained and complete unit-level metrics, and companywide compensation parity. The authors illustrate how patching works and point out some common stumbling blocks.

  15. Analysis of Stub Loaded Microstrip Patch Antennas

    NASA Technical Reports Server (NTRS)

    Bailey, M. C.; Deshpande, M. D.

    1997-01-01

    A microstrip patch antenna fed by a coaxial probe and reactively loaded by a open circuited microstrip line has been used previously to produce circular polarization[ l] and also as a building block for a series fed microstrip patch array [2]. Rectangular and circular patch antennas loaded with a microstrip stub were previously analyzed using the generalized Thevenin theorem [2,3]. In the Thevenin theorem approach, the mutual coupling between the patch current and the surface current on the stub was not taken into account. Also, the Thevenin theorem approach neglects continuity of current at the patch-stub junction. The approach in this present paper includes the coupling between the patch and stub currents as well as continuity at the patch-stub junction.

  16. Synchronous extinction of North America's Pleistocene mammals.

    PubMed

    Faith, J Tyler; Surovell, Todd A

    2009-12-08

    The late Pleistocene witnessed the extinction of 35 genera of North American mammals. The last appearance dates of 16 of these genera securely fall between 12,000 and 10,000 radiocarbon years ago (approximately 13,800-11,400 calendar years B.P.), although whether the absence of fossil occurrences for the remaining 19 genera from this time interval is the result of sampling error or temporally staggered extinctions is unclear. Analysis of the chronology of extinctions suggests that sampling error can explain the absence of terminal Pleistocene last appearance dates for the remaining 19 genera. The extinction chronology of North American Pleistocene mammals therefore can be characterized as a synchronous event that took place 12,000-10,000 radiocarbon years B.P. Results favor an extinction mechanism that is capable of wiping out up to 35 genera across a continent in a geologic instant.

  17. Guatemalan forest synthesis after Pleistocene aridity.

    PubMed

    Leyden, B W

    1984-08-01

    Sediments from two lakes in the Peten Department, Guatemala, provide palynological evidence from Central America of late Pleistocene aridity and subsequent synthesis of mesic forests. Late Glacial vegetation consisted of marsh, savanna, and juniper scrub. An early Holocene temperate forest preceded a mesic tropical forest with Brosimum (ramon). Thus "primeval" rain forests of Guatemala are no older than 10,000 to 11,000 years and are considerably younger in the Peten due to Mayan disturbances. Among dated Neotropical sites, the Peten has the most mesic vegetation yet shown to have supplanted xeric vegetation present during the Pleistocene. The arid late Glacial-humid early Holocene transition appears to have been pantropical in the lowlands. The Peten was not a Pleistocene refugium for mesophytic taxa, as has been suggested. Thus genesis of extant rain forests in northern Central America and southern Mexico remains unexplained.

  18. Guatemalan forest synthesis after Pleistocene aridity

    PubMed Central

    Leyden, Barbara W.

    1984-01-01

    Sediments from two lakes in the Peten Department, Guatemala, provide palynological evidence from Central America of late Pleistocene aridity and subsequent synthesis of mesic forests. Late Glacial vegetation consisted of marsh, savanna, and juniper scrub. An early Holocene temperate forest preceded a mesic tropical forest with Brosimum (ramon). Thus “primeval” rain forests of Guatemala are no older than 10,000 to 11,000 years and are considerably younger in the Peten due to Mayan disturbances. Among dated Neotropical sites, the Peten has the most mesic vegetation yet shown to have supplanted xeric vegetation present during the Pleistocene. The arid late Glacial-humid early Holocene transition appears to have been pantropical in the lowlands. The Peten was not a Pleistocene refugium for mesophytic taxa, as has been suggested. Thus genesis of extant rain forests in northern Central America and southern Mexico remains unexplained. Images PMID:16593498

  19. Synchronous extinction of North America's Pleistocene mammals

    PubMed Central

    Faith, J. Tyler; Surovell, Todd A.

    2009-01-01

    The late Pleistocene witnessed the extinction of 35 genera of North American mammals. The last appearance dates of 16 of these genera securely fall between 12,000 and 10,000 radiocarbon years ago (≈13,800–11,400 calendar years B.P.), although whether the absence of fossil occurrences for the remaining 19 genera from this time interval is the result of sampling error or temporally staggered extinctions is unclear. Analysis of the chronology of extinctions suggests that sampling error can explain the absence of terminal Pleistocene last appearance dates for the remaining 19 genera. The extinction chronology of North American Pleistocene mammals therefore can be characterized as a synchronous event that took place 12,000–10,000 radiocarbon years B.P. Results favor an extinction mechanism that is capable of wiping out up to 35 genera across a continent in a geologic instant. PMID:19934040

  20. Substratum type and conspecific density as drivers of mussel patch formation

    NASA Astrophysics Data System (ADS)

    Bertolini, Camilla; Geraldi, Nathan R.; Montgomery, W. I.; O'Connor, Nessa E.

    2017-03-01

    Biogenic reefs are an important component of aquatic ecosystems where they enhance biodiversity. These reefs are often established by dense aggregations of a single taxa and understanding the fundamental principles of biogenic reef formation is needed for their conservation and restoration. We tested whether substratum type and density affected the aggregation behaviour of two important biogenic-reef forming species, the horse mussel, Modiolus modiolus (Linnaeus, 1758), and the blue mussel, Mytilus edulis (Linnaeus, 1758). First, we tested for effects of substratum type on mussel movement and aggregation behaviour by manipulating substrata available to mussels in mesocosms (three treatments: no sediment added, sediment added, sediment and shells added). Both mussel species moved less in treatments with sediment and with both sediment and shells present than when no sediment or shells were added and the percentage of these mussels that aggregated (clumps of two or more individuals) was lower when shells were present compared to treatments without shells, however, fewer M. modiolus attached to shells than M. edulis. There was no effect of different substratum type on patch complexity of either mussel species. In addition, motivated by our interest in the restoration of M. modiolus, we also tested experimentally whether the aggregation behaviour of M. modiolus was density-dependent. M. modiolus moved a similar distance in three density treatments (100, 200 and 300 mussels m- 2), however, their aggregation rate appeared to be greater when mussel density was higher, suggesting that the encounter rate of individuals is an important factor for aggregation. M. modiolus also formed aggregations with a higher fractal dimension in the high and medium density treatments compared to lower density, suggesting that at higher density this increased patch complexity could further facilitate increased recruitment with the enhanced habitat available for settlement. These findings add

  1. Repeated invasions into the twilight zone: evolutionary origins of a novel assemblage of fishes from deep Caribbean reefs.

    PubMed

    Tornabene, Luke; Van Tassell, James L; Robertson, D Ross; Baldwin, Carole C

    2016-08-01

    Mesophotic and deeper reefs of the tropics are poorly known and underexplored ecosystems worldwide. Collectively referred to as the 'twilight zone', depths below ~30-50 m are home to many species of reef fishes that are absent from shallower depths, including many undescribed and endemic species. We currently lack even a basic understanding of the diversity and evolutionary origins of fishes on tropical mesophotic reefs. Recent submersible collections in the Caribbean have provided new specimens that are enabling phylogenetic reconstructions that incorporate deep-reef representatives of tropical fish genera. Here, we investigate evolutionary depth transitions in the family Gobiidae (gobies), the most diverse group of tropical marine fishes. Using divergence-time estimation coupled with stochastic character mapping to infer the timing of shallow-to-deep habitat transitions in gobies, we demonstrate at least four transitions from shallow to mesophotic depths. Habitat transitions occurred in two broad time periods (Miocene, Pliocene-Pleistocene), and may have been linked to the availability of underutilized niches, as well as the evolution of morphological/behavioural adaptations for life on deep reefs. Further, our analysis shows that at least three evolutionary lineages that invaded deep habitats subsequently underwent speciation, reflecting another unique mode of radiation within the Gobiidae. Lastly, we synthesize depth distributions for 95 species of Caribbean gobies, which reveal major bathymetric faunal breaks at the boundary between euphotic and mesophotic reefs. Ultimately, our study is the first rigorous investigation into the origin of Caribbean deep-reef fishes and provides a framework for future studies that utilize rare, deep-reef specimens.

  2. Marine erosion rates and coastal morphology of reef limestones on Grand Cayman Island, West Indies

    NASA Astrophysics Data System (ADS)

    Spencer, Tom

    1985-09-01

    Direct measurements of surface lowering, using the micro-erosion meter technique, have been obtained from Pleistocene and Tertiary limestones in subtidal and intertidal environments on Grand Cayman Island, West Indies. Overall, erosion rates averaged 0.99 mm yr-1; however this figure conceals the fact that the mean erosion rate on open coasts (X=2.77 mm yr-1) was over six times greater than the rate on reef-protected shores (X=0.45 mm yr-1). On lagoonal rocky coasts abrasion and biological action appear to be the dominant erosional processes, but on coasts exposed to high wave surf, bioconstruction dominates over bio-erosion and surface erosion is slight (X=0.17 mm yr-1). Thus, the magnitude and relative importance of physical, chemical and biological erosion processes differ from one locality to the next with variations in coastal exposure and between reef areas with changes in tidal range and wave regime.

  3. [Reef fishes community structure in 4 atolls of the San Andrés - Providencia Archipelago (Southwestern Caribbean)].

    PubMed

    Mejía, L S; Garzón-Ferreira, J

    2000-12-01

    In 1994 and 1995, 131 visual censuses of reef fishes were made using the stationary sampling method in Courtown, Albuquerque, Serrana and Roncador, four atolls of the Archipelago of San Andrés and Old Providence in the Southwestern Caribbean. Fish species and their abundances were recorded in four geomorphologic zones: lagoon, windward barrier reef, windward terrace and forereef terrace. A total of 98 species were censused; the most abundant were Chromis cyanea (14%), Clepticus parra (14%) and Stegastes partitus (10%). The most abundant families were Pomacentridae (37%), Labridae (28%) and Scaridae (10%). Analysis of similarities showed that differences between zones were greater than differences between atolls, but lagoon and forereef terrace were not significantly different. Cluster and ordination analysis confirmed these results; in addition, the ordination analysis placed the groups according to depth and wave-exposure gradients, suggesting that these two physical variables were responsibles for the clustering. Differences in equitability and species richness appear also due to these variables. Inverse analysis showed in each group few characteristic species, then the differences between zones were due specially to dominance of some species. The dominant trophic categories were planktivorous and herbivorous that were significantly different between zones. In shallow zones (shallow lagoonal patch reefs) and high wave-exposed zones (winward barrier reef) dominated herbivorous fishes, while in deeper zones (terraces and deep lagoonal patch reefs) planktivorous were more abundant.

  4. Home Reef, South Pacific

    NASA Technical Reports Server (NTRS)

    2006-01-01

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

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

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

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

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

    PubMed Central

    Uthicke, Sven; Furnas, Miles; Lønborg, Christian

    2014-01-01

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

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

    PubMed

    Uthicke, Sven; Furnas, Miles; Lønborg, Christian

    2014-01-01

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

  7. Artificial Reefs and Ocean Dumping.

    ERIC Educational Resources Information Center

    Glueck, Richard D.

    1983-01-01

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

  8. Commencement on a Coral Reef

    ERIC Educational Resources Information Center

    Webster, Steven K.

    1973-01-01

    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)

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  10. Coral reef bleaching: ecological perspectives

    NASA Astrophysics Data System (ADS)

    Glynn, P. W.

    1993-03-01

    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 the present suggest that the frequency (60 major events from 1979 to 1990), scale (co-occurrence in many coral reef regions and often over the bathymetric depth range of corals) and severity (>95% mortality in some areas) of recent bleaching disturbances are unprecedented in the scientific literature. The causes of small scale, isolated bleaching events can often be explained by particular stressors (e.g., temperature, salinity, light, sedimentation, aerial exposure and pollutants), but attempts to explain large scale bleaching events in terms of possible global change (e.g., greenhouse warming, increased UV radiation flux, deteriorating ecosystem health, or some combination of the above) have not been convincing. Attempts to relate the severity and extent of large scale coral reef bleaching events to particular causes have been hampered by a lack of (a) standardized methods to assess bleaching and (b) continuous, long-term data bases of environmental conditions over the periods of interest. An effort must be made to understand the impact of bleaching on the remainder of the reef community and the long-term effects on competition, predation, symbioses, bioerosion and substrate condition, all factors that can influence coral recruitment and reef recovery. If projected rates of sea warming are realized by mid to late AD 2000, i.e. a 2°C increase in high latitude coral seas, the upper thermal tolerance limits of many reef-building corals could be exceeded. Present evidence suggests that many corals would be unable to adapt

  11. Nitrification on a coral reef.

    PubMed

    Webb, K L; Wiebe, W J

    1975-09-01

    We report that the algal pavement just behind the reef crest at Enewetak Atoll produces nitrate at measurable rates. In situ and in vitro incubations with N-Serve indicate that the autotrophic pathway involving two separate organisms is effective in this oxidation of ammonia to nitrate. Significant nitrification is indicated throughout the reef environment; Nitrobacter agilis has specifically been identified as at least one of the organisms responsible for the terminal oxidation of nitrite to nitrate.

  12. Fish Assemblages on Estuarine Artificial Reefs: Natural Rocky-Reef Mimics or Discrete Assemblages?

    PubMed Central

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

    2013-01-01

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

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

    PubMed

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

    2014-01-01

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

  14. Ecology of the south Florida coral reefs: a community profile

    SciTech Connect

    Jaap, W.C.

    1984-08-01

    An overview of coral reef research in southern Florida is provided as a prelude to a genuine description of the coral reef ecosystem in the Florida Keys and surrounding environments. Coral reef community types, reef benthos, plankton and reef fish are given specific treatment. Coral reef ecology and management are described. 27 figs., 31 tabs.

  15. Metamorphosing reef fishes avoid predator scent when choosing a home.

    PubMed

    Vail, Alexander L; McCormick, Mark I

    2011-12-23

    Most organisms possess anti-predator adaptations to reduce their risk of being consumed, but little is known of the adaptations prey employ during vulnerable life-history transitions when predation pressures can be extreme. We demonstrate the use of a transition-specific anti-predator adaptation by coral reef fishes as they metamorphose from pelagic larvae to benthic juveniles, when over half are consumed within 48 h. Our field experiment shows that naturally settling damselfish use olfactory, and most likely innate, predator recognition to avoid settling to habitat patches manipulated to emit predator odour. Settlement to patches emitting predator odour was on average 24-43% less than to control patches. Evidence strongly suggests that this avoidance of sedentary and patchily distributed predators by nocturnal settlers will gain them a survival advantage, but also lead to non-lethal predator effects: the costs of exhibiting anti-predator adaptations. Transition-specific anti-predator adaptations, such as demonstrated here, may be widespread among organisms with complex life cycles and play an important role in prey population dynamics.

  16. Miocene precursors to Great Barrier Reef

    SciTech Connect

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

    1988-01-01

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

  17. Adaptation of prey and predators between patches.

    PubMed

    Wang, Wendi; Takeuchi, Yasuhiro

    2009-06-21

    Mathematical models are proposed to simulate migrations of prey and predators between patches. In the absence of predators, it is shown that the adaptation of prey leads to an ideal spatial distribution in the sense that the maximal capacity of each patch is achieved. With the introduction of co-adaptation of predators, it is proved that both prey and predators achieve ideal spatial distributions when the adaptations are weak. Further, it is shown that the adaptation of prey and predators increases the survival probability of predators from the extinction in both patches to the persistence in one patch. It is also demonstrated that there exists a pattern that prey and predators cooperate well through adaptations such that predators are permanent in every patch in the case that predators become extinct in each patch in the absence of adaptations. For strong adaptations, it is proved that the model admits periodic cycles and multiple stability transitions.

  18. Temporal labyrinths of eastern Eurasian Pleistocene humans

    PubMed Central

    Wu, Xiu-Jie; Crevecoeur, Isabelle; Liu, Wu; Xing, Song; Trinkaus, Erik

    2014-01-01

    One of the morphological features that has been identified as uniquely derived for the western Eurasian Neandertals concerns the relative sizes and positions of their semicircular canals. In particular, they exhibit a relatively small anterior canal, a relatively larger lateral one, and a more inferior position of the posterior one relative to the lateral one. These discussions have not included full paleontological data on eastern Eurasian Pleistocene human temporal labyrinths, which have the potential to provide a broader context for assessing Pleistocene Homo trait polarities. We present the temporal labyrinths of four eastern Eurasian Pleistocene Homo, one each of Early (Lantian 1), Middle (Hexian 1), and Late (Xujiayao 15) Pleistocene archaic humans and one early modern human (Liujiang 1). The labyrinths of the two earlier specimens and the most recent one conform to the proportions seen among western early and recent modern humans, reinforcing the modern human pattern as generally ancestral for the genus Homo. The labyrinth of Xujiayao 15 is in the middle of the Neandertal variation and separate from the other samples. This eastern Eurasian labyrinthine dichotomy occurs in the context of none of the distinctive Neandertal external temporal or other cranial features. As such, it raises questions regarding possible cranial and postcranial morphological correlates of Homo labyrinthine variation, the use of individual “Neandertal” features for documenting population affinities, and the nature of late archaic human variation across Eurasia. PMID:25002467

  19. CoBOP Coral Reefs: Optical Closure of a Coral Reef Submarine Light Field

    DTIC Science & Technology

    2001-09-30

    CoBOP Coral Reefs : Optical Closure of a Coral Reef Submarine Light Field Dr. Charles S. Yentsch Bigelow Laboratory McKown Point Road West...2001 to 00-00-2001 4. TITLE AND SUBTITLE CoBOP Coral Reefs : Optical Closure of a Coral Reef Submarine Light Field 5a. CONTRACT NUMBER 5b. GRANT

  20. Foil Patches Seal Small Vacuum Leaks

    NASA Technical Reports Server (NTRS)

    Spiegel, Kirk W.; Reed, David W.

    1995-01-01

    Report discloses technique to patch holes in nickel-alloy rocket-engine nozzle parts prior to vacuum brazing. Technique involves lightly spot-welding nickel foil 0.002 in. thick over hole patched, then spot-welding corrosion-resistant steel foil of same thickness over nickel foil. Once patches subject to pressure and temperature of vacuum brazing, nickel foil diffuses to bond with nickel-alloy nozzle, making vacuum-tight seal.

  1. Measurement and control of electrostatic patch potentials

    NASA Astrophysics Data System (ADS)

    Garrett, Joseph L.; Munday, Jeremy N.

    Electrostatic patch potentials hinder many precision measurements, particularly measurements of the Casimir force. Despite the improved force sensitivity achieved over the last decade, only recently have attempts been made to measure and quantify the effects of patch potentials. Here we present an analysis of patch potentials measured by Kelvin probe force microscopy (KPFM) and discuss methods to control these potentials (e.g. humidity, material choice, etc).

  2. Multi-Mode Broadband Patch Antenna

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R. (Inventor)

    2001-01-01

    A multi-mode broad band patch antenna is provided that allows for the same aperture to be used at independent frequencies such as reception at 19 GHz and transmission at 29 GHz. Furthermore, the multi-mode broadband patch antenna provides a ferroelectric film that allows for tuning capability of the multi-mode broadband patch antenna over a relatively large tuning range. The alternative use of a semiconductor substrate permits reduced control voltages since the semiconductor functions as a counter electrode.

  3. RF MEMS reconfigurable triangular patch antenna.

    SciTech Connect

    Nordquist, Christopher Daniel; Christodoulou, Christos George; Feldner, Lucas Matthew

    2005-01-01

    A Ka-band RF MEMS enabled frequency reconfigurable triangular microstrip patch antenna has been designed for monolithic integration with RF MEMS phase shifters to demonstrate a low-cost monolithic passive electronically scanned array (PESA). This paper introduces our first prototype reconfigurable triangular patch antenna currently in fabrication. The aperture coupled patch antenna is fabricated on a dual-layer quartz/alumina substrate using surface micromachining techniques.

  4. RF MEMS reconfigurable triangular patch antenna.

    SciTech Connect

    Christodoulou, Christos George; Nordquist, Christopher Daniel; Feldner, Lucas Matthew

    2005-07-01

    A Ka-band RF MEMS enabled frequency reconfigurable triangular microstrip patch antenna has been designed for monolithic integration with RF MEMS phase shifters to demonstrate a low-cost monolithic passive electronically scanned array (PESA). This paper introduces our first prototype reconfigurable triangular patch antenna currently in fabrication. The aperture coupled patch antenna is fabricated on a dual-layer quartz/alumina substrate using surface micromachining techniques.

  5. Patch definition in metapopulation analysis: a graph theory approach to solve the mega-patch problem.

    PubMed

    Cavanaugh, Kyle C; Siegel, David A; Raimondi, Peter T; Alberto, Filipe

    2014-02-01

    The manner in which patches are delineated in spatially realistic metapopulation models will influence the size, connectivity, and extinction and recolonization dynamics of those patches. Most commonly used patch-definition methods focus on identifying discrete, contiguous patches of habitat from a single temporal observation of species occurrence or from a model of habitat suitability. However, these approaches are not suitable for many metapopulation systems where entire patches may not be fully colonized at a given time. For these metapopulation systems, a single large patch of habitat may actually support multiple, interacting subpopulations. The interactions among these subpopulations will be ignored if the patch is treated as a single unit, a situation we term the "mega-patch problem." Mega-patches are characterized by variable intra-patch synchrony, artificially low inter-patch connectivity, and low extinction rates. One way to detect this problem is by using time series data to calculate demographic synchrony within mega-patches. We present a framework for identifying subpopulations in mega-patches using a combination of spatial autocorrelation and graph theory analyses. We apply our approach to southern California giant kelp (Macrocystis pyrifera) forests using a new, long-term (27 years), satellite-based data set of giant kelp canopy biomass. We define metapopulation patches using our method as well as several other commonly used patch delineation methodologies and examine the colonization and extinction dynamics of the metapopulation under each approach. We find that the relationships between patch characteristics such as area and connectivity and the demographic processes of colonizations and extinctions vary among the different patch-definition methods. Our spatial-analysis/graph-theoretic framework produces results that match theoretical expectations better than the other methods. This approach can be used to identify subpopulations in metapopulations

  6. [Glossodynia--indication for patch testing?].

    PubMed

    Bäurle, G; Schönberger, A

    1986-08-15

    100 patients suffering from glossodynia without pathologic changes of the oral mucosa and 16 patients with suspected allergic contact stomatitis underwent patch testing using standard patch test and dental materials. The results were compared with those of patients in dental occupations suffering from hand eczema. As there is no clinical relevance of allergens in patients with glossodynia, patch testing seems to be unnecessary. On the other hand, patch test results of patients with stomatitis and dentures often suggest a causal allergy. In most of those cases, this was confirmed by complete healing after changing the denture bases, whereas in glossodynia such replacements never brought about a convincing improvement of the symptoms.

  7. The "edge effect" with patch test materials.

    PubMed

    Fyad, A; Masmoudi, M L; Lachapelle, J M

    1987-03-01

    A positive "edge effect", i.e., the accumulation on the skin of a chemical solution (such as fluorescein 0.01% in a 50/50 water-ethanol solution) at the periphery of the patch test sites has been demonstrated. It occurs with different test materials (Finn Chamber; Silver Patch Test; Patch Test Chamber). Practical implications are discussed: this observation could be important when discussing results of laboratory investigations. In clinical practice, it could explain the occurrence of "ring-shaped" positive allergic patch test reactions to chemicals used in solution, i.e., Kathon CG or hydrocortisone.

  8. Collection of analytes from microneedle patches.

    PubMed

    Romanyuk, Andrey V; Zvezdin, Vasiliy N; Samant, Pradnya; Grenader, Mark I; Zemlyanova, Marina; Prausnitz, Mark R

    2014-11-04

    Clinical medicine and public health would benefit from simplified acquisition of biological samples from patients that can be easily obtained at point of care, in the field, and by patients themselves. Microneedle patches are designed to serve this need by collecting dermal interstitial fluid containing biomarkers without the dangers, pain, or expertise needed to collect blood. This study presents novel methods to collect biomarker analytes from microneedle patches for analysis by integration into conventional analytical laboratory microtubes and microplates. Microneedle patches were made out of cross-linked hydrogel composed of poly(methyl vinyl ether-alt-maleic acid) and poly(ethylene glycol) prepared by micromolding. Microneedle patches were shown to swell with water up to 50-fold in volume, depending on degree of polymer cross-linking, and to collect interstitial fluid from the skin of rats. To collect analytes from microneedle patches, the patches were mounted within the cap of microcentrifuge tubes or formed the top of V-bottom multiwell microplates, and fluid was collected in the bottom of the tubes under gentle centrifugation. In another method, microneedle patches were attached to form the bottom of multiwell microplates, thereby enabling in situ analysis. The simplicity of biological sample acquisition using microneedle patches coupled with the simplicity of analyte collection from microneedles patches integrated into conventional analytical equipment could broaden the reach of future screening, diagnosis, and monitoring of biomarkers in healthcare and environmental/workplace settings.

  9. Functional connectivity from a reef fish perspective: behavioral tactics for moving in a fragmented landscape.

    PubMed

    Turgeon, Katrine; Robillard, Audrey; Grégoire, Jacinthe; Duclos, Vanessa; Kramer, Donald L

    2010-11-01

    Functional connectivity, the degree to which the landscape facilitates or impedes movement, depends on how animals perceive costs and benefits associated with habitat features and integrate them into a movement path. There have been few studies on functional connectivity in marine organisms, despite its importance for the effectiveness of Marine Protected Areas. In this study, we asked how open sand and conspecific distribution affected functional connectivity of longfin damselfish (Stegastes diencaeus) on fringing reefs in Barbados. We translocated 102 individuals to sites varying in sand gap width and in configuration: Continuous (solid reef between release site and territory); Detour (sand along the direct path between release site and territory, but an alternative, continuous solid U-shaped reef path); and Patch (sand between release site and territory, but an alternative stepping stone path). We visually tracked and mapped every homing path. We found no evidence of a barrier to movement in the Continuous configuration, but sand was a partial barrier in Detour and Patch configurations. The probability of crossing the sand gap dropped below 50% when its width was > 1.85 m in Detour and > 3.90 m in Patch configuration. Damselfish avoiding large gaps took detours that approximated the route maximizing travel over reef, but they crossed more short sand gaps and fewer conspecific territories, suggesting avoidance of agonistic interactions. This study quantifies for the first time the size and steepness of a barrier to movement in a marine organism, and it provides evidence for effects of both landscape configuration and conspecific distribution on functional connectivity.

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  11. Two Holes in 'Wooly Patch'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The rock abrasion tool on NASA's Mars Exploration Rover Spirit ground two holes in a relatively soft rock called 'Wooly Patch' near the base of the 'Columbia Hills' inside Gusev Crater on Mars. This approximately true-color image from the panoramic camera was taken on sol 200 (July 25, 2004) and generated using the camera's 600-, 530-, and 480-nanometer filters. It shows the natural red and reddish-brown color of the rock. Scientists speculate that this relatively soft rock (compared to others analyzed by Spirit) may have been modified by water. Small cracks in the surface outside the drill holes may be the result of interactions with water-rich fluids.

  12. Pleistocene carbonate stratigraphy of South Florida: Evidence for high-frequency sea-level cyclicity

    USGS Publications Warehouse

    Hickey, Todd D.; Hine, Albert C.; Shinn, Eugene A.; Kruse, Sarah E.; Poore, Richard Z.

    2010-01-01

    Pleistocene carbonates of south Florida and islands of the Florida Keys are currently divided into five marine sequences designated, from oldest to youngest, the Q1–Q5 units. The units include a mosaic of freshwater and shallow marine deposits that accumulated on the Florida platform during high sea-level stands. The units are separated by regional-scale subaerial-exposure surfaces that formed during glacioeustatic lowstands. Analyses of cores recovered at Grossman Ridge Rock Reef and Joe Ree Rock Reef in the Florida Everglades reveal additional subaerial-exposure surfaces that are used to delineate subdivisions within units Q1 (Q1a–Q1b), Q2 (Q2a–Q2d), and Q4 (Q4a–Q4b). Units Q1–Q5 preserve evidence of at least 10 separate sea-level highstands, rather than 5 as indicated by previous studies. Compilation of available uranium-series dates on corals recovered from the Florida Keys indicates that the Q4 unit accreted during sea-level maxima associated with marine oxygen-isotope Stage 9 (Q4a) and isotope Stage 7 (Q4b). The Q5 unit formed during isotope Stage 5. No reliable dates are available for units Q1–Q3. We infer that unit Q3 was formed during the extended sea-level highstand of isotope Stage 11 and that units Q2 and Q1 predate isotope Stage 11.

  13. CoBOP Coral Reefs: Optical Closure of a Coral Reef Submarine Light Field

    DTIC Science & Technology

    2002-09-30

    CoBOP Coral Reefs : Optical Closure of a Coral Reef Submarine Light Field Dr. Charles S. Yentsch Bigelow Laboratory McKown Point Road West...TYPE 3. DATES COVERED 00-00-2002 to 00-00-2002 4. TITLE AND SUBTITLE CoBOP Coral Reefs : Optical Closure of a Coral Reef Submarine Light Field...remote assessment of salinity and ocean color in Florida Bay. In: The Everglades, Florida Bay and Coral Reefs of the Florida Keys: An Ecosystem

  14. CoBOP Coral Reefs: Optical Closure of a Coral Reef Submarine Light Field

    DTIC Science & Technology

    1999-09-30

    CoBOP Coral Reefs : Optical Closure of a Coral Reef Submarine Light Field Charles S. Yentsch Bigelow Laboratory for Ocean Sciences 180 McKown Point W...REPORT TYPE 3. DATES COVERED 00-00-1999 to 00-00-1999 4. TITLE AND SUBTITLE CoBOP Coral Reefs : Optical Closure of a Coral Reef Submarine...affecting the decline of coral reefs is change in water transparency driven by anthropogenic rather than natural processes. Corals are known to

  15. Spatial patterns in benthic communities and the dynamics of a mosaic ecosystem on the Great Barrier Reef, Australia

    NASA Astrophysics Data System (ADS)

    Ninio, R.; Meekan, M.

    2002-04-01

    The benthic communities of the Great Barrier Reef (GBR) have been characterized as a mosaic with patches at scales of tens to hundreds of kilometres formed by clusters of reefs with comparable environmental settings and histories of disturbance. We use data sets of changes in cover of abundant benthic organisms to examine the relationship between community composition and the dynamics of this mosaic. Our data were compiled from seven annual video surveys of permanent transects on the north-east flanks of up to 52 reefs at different shelf positions throughout most of the GBR. Classification analysis of these data sets identified three distinct groups of reefs, the first dominated by poritid hard corals and alcyoniid soft corals, the second by hard corals of the genus Acropora, and the third by xeniid soft corals. These groups underwent different amounts of change in cover during the period of our study. As acroporan corals are fast growing but susceptible to mortality due to predators and wave action, the group of reefs dominated by this genus displayed rapid rates of growth and loss of cover. In contrast, cover in the remaining groups changed very slowly or remained stable. Some evidence suggests that competition for space may limit growth of acroporan corals and thus rates of change in the group dominated by xeniid soft corals. These contrasting patterns imply that susceptibility to, and recovery from, disturbances such as cyclones, predators, and bleaching events will differ among these groups of reefs.

  16. Facies and diagenesis of upper Tertiary-Pleistocene platform carbonates in a 300m borehole, southern Ambergris Caye, Belize

    SciTech Connect

    Burtnett, C.A. )

    1996-01-01

    Well cuttings from an [approx]300 m-deep borehole drilled by the Belize government on Ambergris Caye were examined for inferred depositional environments, mineralogy, and stable oxygen-carbon isotopic compositions. The recovered section composes carbonates of the Barton Creek and ( )Sand Hill Formations, presumably of upper-most Tertiary to Pleistocene age. Location of the wellbore to the west of the exposed Pleistocene and superposed Holocene platform margin reef suggests continuous platform deposition. Comparison to modem facies indicates that the entire section is, in fact, mostly outer-shelf reef and immediate back-reef facies. Four unconformities are recognized in the upper 150 m of section on the basis of microbreccias and calcretes, and they truncate stacked, shallowing-upward cycles within the section. Depleted [delta][sup 18]O and [delta][sup 13]C compositions of whole-rock samples from the upper 150 m, which are highly porous and LMC-dominated, range from -2.5 to -5 [per thousand] and -3 to -7 [per thousand] (PDB), respectively. Unconformities are therefore believed to be subaerial exposure surfaces. Dolomite (replacive and cement) occurs below 150 m within HMC-dominated limestones that also contain aragonite. Dolomite generally increases with depth from 8-28%, its composition varies from Ca[sub 51-57], and its mean isotopic composition is [delta][sup 18]O = 3.2 [per thousand] and [delta][sup 13]C = 2.5 o/oo. There are no depth-related trends in dolomite stoichiometry or isotopic composition. Although the timing and site of dolomitization are not known, available data suggest formation from circulating marine fluids of near-normal composition.

  17. Facies and diagenesis of upper Tertiary-Pleistocene platform carbonates in a 300m borehole, southern Ambergris Caye, Belize

    SciTech Connect

    Burtnett, C.A.

    1996-12-31

    Well cuttings from an {approx}300 m-deep borehole drilled by the Belize government on Ambergris Caye were examined for inferred depositional environments, mineralogy, and stable oxygen-carbon isotopic compositions. The recovered section composes carbonates of the Barton Creek and (?)Sand Hill Formations, presumably of upper-most Tertiary to Pleistocene age. Location of the wellbore to the west of the exposed Pleistocene and superposed Holocene platform margin reef suggests continuous platform deposition. Comparison to modem facies indicates that the entire section is, in fact, mostly outer-shelf reef and immediate back-reef facies. Four unconformities are recognized in the upper 150 m of section on the basis of microbreccias and calcretes, and they truncate stacked, shallowing-upward cycles within the section. Depleted {delta}{sup 18}O and {delta}{sup 13}C compositions of whole-rock samples from the upper 150 m, which are highly porous and LMC-dominated, range from -2.5 to -5 {per_thousand} and -3 to -7 {per_thousand} (PDB), respectively. Unconformities are therefore believed to be subaerial exposure surfaces. Dolomite (replacive and cement) occurs below 150 m within HMC-dominated limestones that also contain aragonite. Dolomite generally increases with depth from 8-28%, its composition varies from Ca{sub 51-57}, and its mean isotopic composition is {delta}{sup 18}O = 3.2 {per_thousand} and {delta}{sup 13}C = 2.5 o/oo. There are no depth-related trends in dolomite stoichiometry or isotopic composition. Although the timing and site of dolomitization are not known, available data suggest formation from circulating marine fluids of near-normal composition.

  18. Nitrogen fixation in a coral reef community.

    PubMed

    Wiebe, W J; Johannes, R E; Webb, K L

    1975-04-18

    Algal reef flats at Enewetak Atoll, Marshall Islands, fix atmospheric nitrogen at rates comparable to those in managed agriculture. The dominant nitrogen fixer appears to be the blue-green alga Calothrix crustacea. Since this nutrient enrichment contributes to the high productivity of adjacent coral reefs and undoubtedly to atoll lagoons, it is recommended that the algal reef flats receive increased conservation priority.

  19. Photography of Coral Reefs from ISS

    NASA Technical Reports Server (NTRS)

    Robinson, Julie A.

    2009-01-01

    This viewgraph presentation reviews the uses of photography from the International Space Station (ISS) in studying Earth's coral reefs. The photographs include reefs in various oceans . The photographs have uses for science in assisting NASA mapping initiatives, distribution worldwide through ReefBase, and by biologist in the field.

  20. REEF: Retainable Evaluator Execution Framework.

    PubMed

    Weimer, Markus; Chen, Yingda; Chun, Byung-Gon; Condie, Tyson; Curino, Carlo; Douglas, Chris; Lee, Yunseong; Majestro, Tony; Malkhi, Dahlia; Matusevych, Sergiy; Myers, Brandon; Narayanamurthy, Shravan; Ramakrishnan, Raghu; Rao, Sriram; Sears, Russell; Sezgin, Beysim; Wang, Julia

    2015-01-01

    Resource Managers like Apache YARN have emerged as a critical layer in the cloud computing system stack, but the developer abstractions for leasing cluster resources and instantiating application logic are very low-level. This flexibility comes at a high cost in terms of developer effort, as each application must repeatedly tackle the same challenges (e.g., fault-tolerance, task scheduling and coordination) and re-implement common mechanisms (e.g., caching, bulk-data transfers). This paper presents REEF, a development framework that provides a control-plane for scheduling and coordinating task-level (data-plane) work on cluster resources obtained from a Resource Manager. REEF provides mechanisms that facilitate resource re-use for data caching, and state management abstractions that greatly ease the development of elastic data processing work-flows on cloud platforms that support a Resource Manager service. REEF is being used to develop several commercial offerings such as the Azure Stream Analytics service. Furthermore, we demonstrate REEF development of a distributed shell application, a machine learning algorithm, and a port of the CORFU [4] system. REEF is also currently an Apache Incubator project that has attracted contributors from several instititutions.

  1. REEF: Retainable Evaluator Execution Framework

    PubMed Central

    Weimer, Markus; Chen, Yingda; Chun, Byung-Gon; Condie, Tyson; Curino, Carlo; Douglas, Chris; Lee, Yunseong; Majestro, Tony; Malkhi, Dahlia; Matusevych, Sergiy; Myers, Brandon; Narayanamurthy, Shravan; Ramakrishnan, Raghu; Rao, Sriram; Sears, Russell; Sezgin, Beysim; Wang, Julia

    2015-01-01

    Resource Managers like Apache YARN have emerged as a critical layer in the cloud computing system stack, but the developer abstractions for leasing cluster resources and instantiating application logic are very low-level. This flexibility comes at a high cost in terms of developer effort, as each application must repeatedly tackle the same challenges (e.g., fault-tolerance, task scheduling and coordination) and re-implement common mechanisms (e.g., caching, bulk-data transfers). This paper presents REEF, a development framework that provides a control-plane for scheduling and coordinating task-level (data-plane) work on cluster resources obtained from a Resource Manager. REEF provides mechanisms that facilitate resource re-use for data caching, and state management abstractions that greatly ease the development of elastic data processing work-flows on cloud platforms that support a Resource Manager service. REEF is being used to develop several commercial offerings such as the Azure Stream Analytics service. Furthermore, we demonstrate REEF development of a distributed shell application, a machine learning algorithm, and a port of the CORFU [4] system. REEF is also currently an Apache Incubator project that has attracted contributors from several instititutions.1 PMID:26819493

  2. Miocene reefs of Dominican Republic

    SciTech Connect

    Evans, C.C.

    1988-01-01

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

  3. Influence of hydrodynamic energy on Holocene reef flat accretion, Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Dechnik, Belinda; Webster, Jody M.; Nothdurft, Luke; Webb, Gregory E.; Zhao, Jian-xin; Duce, Stephanie; Braga, Juan C.; Harris, Daniel L.; Vila-Concejo, Ana; Puotinen, Marji

    2016-01-01

    The response of platform reefs to sea-level stabilization over the past 6 ka is well established for the Great Barrier Reef (GBR), with reefs typically accreting laterally from windward to leeward. However, these observations are based on few cores spread across reef zones and may not accurately reflect a reef's true accretional response to the Holocene stillstand. We present a new record of reef accretion based on 49 U/Th ages from Heron and One Tree reefs in conjunction with re-analyzed data from 14 reefs across the GBR. We demonstrate that hydrodynamic energy is the main driver of accretional direction; exposed reefs accreted primarily lagoon-ward while protected reefs accreted seawards, contrary to the traditional growth model in the GBR. Lateral accretion rates varied from 86.3 m/ka-42.4 m/ka on the exposed One Tree windward reef and 68.35 m/ka-15.7 m/ka on the protected leeward Heron reef, suggesting that wind/wave energy is not a dominant control on lateral accretion rates. This represents the most comprehensive statement of lateral accretion direction and rates from the mid-outer platform reefs of the GBR, confirming great variability in reef flat growth both within and between reef margins over the last 6 ka, and highlighting the need for closely-spaced transects.

  4. HotPatch Web Gateway: Statistical Analysis of Unusual Patches on Protein Surfaces

    DOE Data Explorer

    Pettit, Frank K.; Bowie, James U. [DOE-Molecular Biology Institute

    HotPatch finds unusual patches on the surface of proteins, and computes just how unusual they are (patch rareness), and how likely each patch is to be of functional importance (functional confidence (FC).) The statistical analysis is done by comparing your protein's surface against the surfaces of a large set of proteins whose functional sites are known. Optionally, HotPatch can also write a script that will display the patches on the structure, when the script is loaded into some common molecular visualization programs. HotPatch generates complete statistics (functional confidence and patch rareness) on the most significant patches on your protein. For each property you choose to analyze, you'll receive an email to which will be attached a PDB-format file in which atomic B-factors (temp. factors) are replaced by patch indices; and the PDB file's Header Remarks will give statistical scores and a PDB-format file in which atomic B-factors are replaced by the raw values of the property used for patch analysis (for example, hydrophobicity instead of hydrophobic patches). [Copied with edits from http://hotpatch.mbi.ucla.edu/

  5. Key Largo Limestone revisited: Pleistocene shelf-edge facies, Florida Keys, USA

    USGS Publications Warehouse

    Gray, Multer H.; Gischler, E.; Lundberg, J.; Simmons, K.R.; Shinn, E.A.

    2002-01-01

    New dates and analysis of 12 deep and 57 shallow cores allow a more detailed interpretation of the Pleistocene shelf edge of the Florida Platform as found in various facies of the Key Largo Limestone beneath the Florida Keys. In this study a three-phase evolution of the Quaternary units (Q1-Q5) of the Key Largo is presented with new subdivision of the Q5. (1) In the first phase, the Q1 and Q2 (perhaps deposited during oxygen-isotope stage 11) deep-water quartz-rich environment evolved into a shallow carbonate phase. (2) Subsequently, a Q3 (presumably corresponding to oxygen-isotope stage 9) flourishing reef and productive high-platform sediment phase developed. (3) Finally, a Q4 and Q5 (corresponding to oxygen-isotope stages 7 and 5) stabilization phase occured with reefs and leeward productive lagoons, followed by lower sea levels presenting a sequence of younger (isotope substages 5c, 5a) shelf-margin wedges, sediment veneers and outlier reefs. The Key Largo Limestone provides an accessible model of a carbonate shelf edge with fluctuating water depth, bordering a deep seaward basin for a period of at least 300 ka. During this time, at least four onlaps/offlaps, often separated by periods of karst development with associated diagenetic alterations, took place. The story presented by this limestone not only allows a better understanding of the history of south Florida but also aids in the interpretation of similar persistent shelf-edge sites bordering deep basins in other areas.

  6. Pleistocene effects on North American songbird evolution

    PubMed Central

    Klicka, J.; Zink, R. M.

    1999-01-01

    Recent studies have used comparisons of mitochondrial DNA (mtDNA) sequence divergence among populations and species to test existing hypotheses about avian evolution during the Pleistocene epoch. In 1998, Avise and Walker concluded that the Pleistocene was an important time for avian evolution, including the initiation of phylogeographic separations and the completion of speciation events that began in the Pliocene. The study implied that these conclusions conflicted with the study, in 1997, by Klicka and Zink, which concluded that most species pairs previously thought to have originated in the past 250 000 years were much older. The two studies are complementary in the sense that Avise and Walker dealt primarily with phylogeographic (intraspecific) separations. Furthermore, Klicka and Zink concentrated on the inception of divergences whereas the Avise and Walker focused on the timing of the completion of speciation. To accomplish this, Avise and Walker analysed 'phylogroups', geographically coherent subsets of biological species in which mtDNA haplotypes exhibit reciprocal monophyly. The study used the average interphylogroup mtDNA distance (0.027), calibrated at 2% per million years, to conclude that speciation required on average one million years to complete. Hence, speciation events begun in the Late Pliocene would have been completed in the mid- to late Pleistocene. Although we appreciate the extended nature of the speciation process and Avise and Walker's insightful attempt to estimate its duration, we conclude that their value was an overestimate by a factor of two. In particular we question whether phylogroups can be used in the novel evolutionary role that Avise and Walker envisioned, because of the vagaries of taxonomic practices and lack of consensus regarding species concepts. To extend their analysis of intraspecific, phylogeographic separations, we compiled previously analysed and newly available data for divergence times for North American songbird

  7. Holocene reef associated carbonate sediments and their Pleistocene counterparts, Miyako Islands, Ryukyus, southwest of Japan

    SciTech Connect

    Tsuji, Yoshihiro; Tsuneo Yamamura; Toshio Kodato; Hisao Sunouchi; Tomoya Yuki

    1988-02-01

    Holocene carbonate sedimentary facies distribution, from sea level to shelf slope about 1,000 m in depth, and its relationship to bathymetry, off Miyako Island, Ryukyus, southwest of Japan were clarified by surveys with sidescan sonar, sparker, uniboom, sea-bottom camera, and sediment sampler.

  8. Transdermal patches: history, development and pharmacology

    PubMed Central

    Pastore, Michael N; Kalia, Yogeshvar N; Horstmann, Michael; Roberts, Michael S

    2015-01-01

    Transdermal patches are now widely used as cosmetic, topical and transdermal delivery systems. These patches represent a key outcome from the growth in skin science, technology and expertise developed through trial and error, clinical observation and evidence-based studies that date back to the first existing human records. This review begins with the earliest topical therapies and traces topical delivery to the present-day transdermal patches, describing along the way the initial trials, devices and drug delivery systems that underpin current transdermal patches and their actives. This is followed by consideration of the evolution in the various patch designs and their limitations as well as requirements for actives to be used for transdermal delivery. The properties of and issues associated with the use of currently marketed products, such as variability, safety and regulatory aspects, are then described. The review concludes by examining future prospects for transdermal patches and drug delivery systems, such as the combination of active delivery systems with patches, minimally invasive microneedle patches and cutaneous solutions, including metered-dose systems. PMID:25560046

  9. Immunoisolation Patch System for Cellular Transplantation

    NASA Technical Reports Server (NTRS)

    Wang, Taylor G. (Inventor)

    2014-01-01

    An immunoisolation patch system, and particularly a patch system comprising multiple immunoisolation microcapsules, each encapsulating biological material such as cells for transplantation, which can be used in the prophylactic and therapeutic treatment of disease in large animals and humans without the need for immunosuppression.

  10. Formulation study of tea tree oil patches.

    PubMed

    Minghetti, Paola; Casiraghi, Antonella; Cilurzo, Francesco; Gambaro, Veniero; Montanari, Luisa

    2009-01-01

    The antimicrobial, antifungal and anti-inflammatory properties of tea tree oil (TTO), the essential oil of Melaleuca alternifolia are well documented. In order to optimize its therapeutic activity, TTO patches were designed. The aim of this work was the formulation of monolayer patches containing TTO. Moreover, the performance of oleic acid (OA) as a skin penetration enhancer in patches was evaluated. Terpinen-4-ol (T4OL), the main component of TTO, was the marker used to evaluate TTO skin permeability. The permeation study was performed through human epidermis by using Franz diffusion cells. Patches were prepared by using methacrylic copolymers, Eudragit E100 (EuE100) or Eudragit NE (EuNE), and a silicone resin, BioPSA7-4602 (Bio-PSA). TTO and OA contents were fixed at 10% w/w and 3% w/w, respectively. The patches were prepared by a casting method and characterised in terms of T4OL content and skin permeability. All the selected polymers were suitable as the main component of the patch matrix. Since the main critical issue in the use of TTO is related to its toxicity after absorption, the local administration of TTO can take advantage of the use of patches based on EuE100 because of the high retained amount and the low permeation of T4OL. In this matrix, OA slightly increased the T4OL retained amount, improving the efficacy and safety of TTO patches.

  11. Holocene aggradation of the Dry Tortugas coral reef ecosystem

    USGS Publications Warehouse

    Brock, J.C.; Palaseanu-Lovejoy, M.; Poore, R.Z.; Nayegandhi, A.; Wright, C.W.

    2010-01-01

    Radiometric age dating of reef cores acquired at the Dry Tortugas coral reef ecosystem (DTCRE) was merged with lidar topographic mapping to examine Holocene reef development linked to spatial variation in growth and erosion under the control of sea level. Analysis of variance of lidar topography confirmed the presence of three distinct terraces on all three major DTCRE banks (Loggerhead Bank, Garden Bank, and Pulaski Bank). Reef building on the middle terrace (T2) began atop Pleistocene edifices on Loggerhead Bank by 8.0 ka (thousands of years ago) and on Garden Bank by 7.2 ka at elevations of about −16.0 m and −11.9 m, respectively, relative to present mean sea level. Following this initiation at different elevations, T2 aggraded vertically on both banks at different rates during the early Holocene under foundering conditions until a highstand at 5.2 ka, resulting in a 2.21 m offset in present mean T2 elevation between these banks. Initiation of an upper terrace (T1) occurred on both Loggerhead Bank and Garden Bank in association with sea-level fall to a lowstand at near 4.8 ka. This upper terrace initiated on Garden Bank at about 5.0 ka and then grew upward at rate of 2.5 mm year−1 until approximately 3.8 ka. On Loggerhead Bank, the upper T1 terrace formed after 4.5 ka at a higher vertical aggradation rate of 4.1 mm year−1, but at a lower elevation than on Garden Bank. Terrace T1 aggraded on Loggerhead Bank below the elevation of lowstands during late Holocene sea-level oscillation, and consequently erosion on Loggerhead Bank was minimal and likely limited to the crest of the upper terrace. In contrast, after 3.8 ka terrace T1 on Garden Bank likely tracked sea level and consequently underwent erosion when sea level fell to second, third and fourth lowstands at 3.3, 1.1, and 0.3 ka.

  12. Patch scales in coastal ecosystems

    NASA Astrophysics Data System (ADS)

    Broitman, Bernardo R.

    Quantifying the spatial and temporal scales over which ecological processes are coupled to environmental variability is a major challenge for ecologists. Here, I assimilate patterns of oceanographic variability with ecological field studies in an attempt to quantify spatial and temporal scales of coupling. Using coastal time series of chlorophyll-a concentration from remote sensing, the first chapter examines the alongshore extent of coastal regions subject to similar temporal patterns of oceanographic variability in Western North America (WNA) and North-Central Chile (Chile). I found striking interhemispherical differences in the length of coastal sections under similar oceanographic regimes, with the Chile region showing longshore coherency over much smaller spatial scales (˜60 km) than on the coast of WNA (˜140 km). Through a spatial analysis of coastal orientation I suggest that the characteristic length scales may be traced to the geomorphologic character of the ocean margins. The second chapter examines spatial patterns of primary production through long-term means of coastal chlorophyll-a concentration and kelp (Macrocystis pyrifera) cover and explores their relationship with coastal geomorphology and sea surface temperature (SST). Spatial analyses showed a striking match in length scales around 180--250 km. Strong anticorrelations at small spatial lags and positive correlations at longer distances suggest little overlap between patches of kelp and coastal chlorophyll-a. In agreement with findings from the previous chapter, I found that coastal patches could be traced back to spatial patterns of coastal geomorphology. Through SST time series and long-term datasets of larval recruitment in Santa Cruz Island, California, the third chapter examines temporal patterns of oceanographic variability as determinants of ecological patterns. SST time series from sites experiencing low larval recruitment rates were dominated by strong temporal variability. These sites

  13. New tool to manage coral reefs

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    The National Oceanic and Atmospheric Administration is making available a new tool for coral reef managers to monitor the cumulative thermal stress of several coral reefs around the world, including the Great Barrier Reef, and reefs by the Galapagos Islands, the agency announced on 25 February.The agency's "Degree Heating Weeks" product uses satellite-derived information to allow continuous monitoring of the extent and acuteness of thermal stress, which are key predictors of coral bleaching, and which contribute to coral reef degradation.

  14. Image Quality Assessment Based on Inter-Patch and Intra-Patch Similarity

    PubMed Central

    Zhou, Fei; Lu, Zongqing; Wang, Can; Sun, Wen; Xia, Shu-Tao; Liao, Qingmin

    2015-01-01

    In this paper, we propose a full-reference (FR) image quality assessment (IQA) scheme, which evaluates image fidelity from two aspects: the inter-patch similarity and the intra-patch similarity. The scheme is performed in a patch-wise fashion so that a quality map can be obtained. On one hand, we investigate the disparity between one image patch and its adjacent ones. This disparity is visually described by an inter-patch feature, where the hybrid effect of luminance masking and contrast masking is taken into account. The inter-patch similarity is further measured by modifying the normalized correlation coefficient (NCC). On the other hand, we also attach importance to the impact of image contents within one patch on the IQA problem. For the intra-patch feature, we consider image curvature as an important complement of image gradient. According to local image contents, the intra-patch similarity is measured by adaptively comparing image curvature and gradient. Besides, a nonlinear integration of the inter-patch and intra-patch similarity is presented to obtain an overall score of image quality. The experiments conducted on six publicly available image databases show that our scheme achieves better performance in comparison with several state-of-the-art schemes. PMID:25793282

  15. Bahamian Pleistocene model for some Mississippian oolites

    SciTech Connect

    Bain, R.J. )

    1989-08-01

    San Salvador Island, unlike most Bahamian islands, is a narrow isolated platform surrounded by deep ocean. Therefore, sedimentary deposits on San Salvador must be explained in terms of processes and settings on this narrow, isolated shelf. Pleistocene oolite occurs between Illinoian and Wisconsinan paleosols. Dune ridges of up to 120 ft are composed of Pleistocene cross-bedded oolitic grainstone, whereas interdunal deposits are bioclastic packstone and wackestone containing abundant Chione cancellata. In lower dunal deposits, bioclastic content increases and the degree of sorting decreases. A fenestral porosity zone occurs approximately 5 ft above present-day sea level. In several ridges, oolite drapes over older paleosol-capped bioclastic ridges. During the Sangamonian, sea water flooded the platform, however some remnant Aftonian ridges remained above sea level. As cold water from the surrounding deep ocean warmed on the shelf, ooids were generated and were washed onto beaches and blown into dunes. Remnant ridges restricted water movement and acted as nucleii for eolian ooid dunes. As sea level continued to rise, ooids were replaced by lagoonal bioclastic deposits. Ooid production was restricted to the swash zone along beaches resulting in the mixture of ooids and bioclastic sand in later Sangamonian deposits. Numerous Mississippian oolites display features similar to the Pleistocene oolite of San Salvador Island. Possible comparisons include thick lenses of Ste. Genevieve and Bangor limestones, paleosols in the Ste. Genevieve halo-shaped bodies of Greenbrier oolite, and the relationship of nearly all olites with bioclastic facies.

  16. Pleistocene vertebrates of the Yukon Territory

    NASA Astrophysics Data System (ADS)

    Harington, C. R.

    2011-08-01

    Unglaciated parts of the Yukon constitute one of the most important areas in North America for yielding Pleistocene vertebrate fossils. Nearly 30 vertebrate faunal localities are reviewed spanning a period of about 1.6 Ma (million years ago) to the close of the Pleistocene some 10 000 BP (radiocarbon years before present, taken as 1950). The vertebrate fossils represent at least 8 species of fishes, 1 amphibian, 41 species of birds and 83 species of mammals. Dominant among the large mammals are: steppe bison ( Bison priscus), horse ( Equus sp.), woolly mammoth ( Mammuthus primigenius), and caribou ( Rangifer tarandus) - signature species of the Mammoth Steppe fauna ( Fig. 1), which was widespread from the British Isles, through northern Europe, and Siberia to Alaska, Yukon and adjacent Northwest Territories. The Yukon faunas extend from Herschel Island in the north to Revenue Creek in the south and from the Alaskan border in the west to Ketza River in the east. The Yukon holds evidence of the earliest-known people in North America. Artifacts made from bison, mammoth and caribou bones from Bluefish Caves, Old Crow Basin and Dawson City areas show that people had a substantial knowledge of making and using bone tools at least by 25 000 BP, and possibly as early as 40 000 BP. A suggested chronological sequence of Yukon Pleistocene vertebrates ( Table 1) facilitates comparison of selected faunas and indicates the known duration of various taxa.

  17. COLLABORATIVE GUIDE: A REEF MANAGER'S GUIDE TO ...

    EPA Pesticide Factsheets

    Innovative strategies to conserve the world's coral reefs are included in a new guide released today by NOAA, and the Australian Great Barrier Reef Marine Park Authority, with author contributions from a variety of international partners from government agencies, non-governmental organizations, and academic institutions. Referred to as A Reef Manager's Guide to Coral Bleaching, the guide will provide coral reef managers with the latest scientific information on the causes of coral bleaching and new management strategies for responding to this significant threat to coral reef ecosystems. Innovative strategies to conserve the world's coral reefs are included in a new guide released today by NOAA, and the Australian Great Barrier Reef Marine Park Authority, with author contributions from a variety of international partners from government agencies, non-governmental organizations, and academic institutions. Dr. Jordan West, of the National Center for Environmental Assessment, was a major contributor to the guide. Referred to as

  18. A deep reef in deep trouble

    USGS Publications Warehouse

    Menza, Charles; Kendall, M.; Rogers, C.; Miller, J.

    2007-01-01

    The well-documented degradation of shallower reefs which are often closer to land and more vulnerable to pollution, sewage and other human-related stressors has led to the suggestion that deeper, more remote offshore reefs could possibly serve as sources of coral and fish larvae to replenish the shallower reefs. Yet, the distribution, status, and ecological roles of deep (>30 m) Caribbean reefs are not well known. In this report, an observation of a deep reef which has undergone a recent extensive loss of coral cover is presented. In stark contrast to the typical pattern of coral loss in shallow reefs, the deeper corals were most affected. This report is the first description of such a pattern of coral loss on a deep reef.

  19. Depth as an Organizing Force in Pocillopora damicornis: Intra-Reef Genetic Architecture

    PubMed Central

    Gorospe, Kelvin D.; Karl, Stephen A.

    2015-01-01

    Relative to terrestrial plants, and despite similarities in life history characteristics, the potential for corals to exhibit intra-reef local adaptation in the form of genetic differentiation along an environmental gradient has received little attention. The potential for natural selection to act on such small scales is likely increased by the ability of coral larval dispersal and settlement to be influenced by environmental cues. Here, we combine genetic, spatial, and environmental data for a single patch reef in Kāne‘ohe Bay, O‘ahu, Hawai‘i, USA in a landscape genetics framework to uncover environmental drivers of intra-reef genetic structuring. The genetic dataset consists of near-exhaustive sampling (n = 2352) of the coral, Pocillopora damicornis at our study site and six microsatellite genotypes. In addition, three environmental parameters – depth and two depth-independent temperature indices – were collected on a 4 m grid across 85 locations throughout the reef. We use ordinary kriging to spatially interpolate our environmental data and estimate the three environmental parameters for each colony. Partial Mantel tests indicate a significant correlation between genetic relatedness and depth while controlling for space. These results are also supported by multi-model inference. Furthermore, spatial Principle Component Analysis indicates a statistically significant genetic cline along a depth gradient. Binning the genetic dataset based on size-class revealed that the correlation between genetic relatedness and depth was significant for new recruits and increased for larger size classes, suggesting a possible role of larval habitat selection as well as selective mortality in structuring intra-reef genetic diversity. That both pre- and post-recruitment processes may be involved points to the adaptive role of larval habitat selection in increasing adult survival. The conservation importance of uncovering intra-reef patterns of genetic diversity is

  20. Management under uncertainty: guide-lines for incorporating connectivity into the protection of coral reefs

    NASA Astrophysics Data System (ADS)

    McCook, L. J.; Almany, G. R.; Berumen, M. L.; Day, J. C.; Green, A. L.; Jones, G. P.; Leis, J. M.; Planes, S.; Russ, G. R.; Sale, P. F.; Thorrold, S. R.

    2009-06-01

    The global decline in coral reefs demands urgent management strategies to protect resilience. Protecting ecological connectivity, within and among reefs, and between reefs and other ecosystems is critical to resilience. However, connectivity science is not yet able to clearly identify the specific measures for effective protection of connectivity. This article aims to provide a set of principles or practical guidelines that can be applied currently to protect connectivity. These ‘rules of thumb’ are based on current knowledge and expert opinion, and on the philosophy that, given the urgency, it is better to act with incomplete knowledge than to wait for detailed understanding that may come too late. The principles, many of which are not unique to connectivity, include: (1) allow margins of error in extent and nature of protection, as insurance against unforeseen or incompletely understood threats or critical processes; (2) spread risks among areas; (3) aim for networks of protected areas which are: (a) comprehensive and spread—protect all biotypes, habitats and processes, etc., to capture as many possible connections, known and unknown; (b) adequate—maximise extent of protection for each habitat type, and for the entire region; (c) representative—maximise likelihood of protecting the full range of processes and spatial requirements; (d) replicated—multiple examples of biotypes or processes enhances risk spreading; (4) protect entire biological units where possible (e.g. whole reefs), including buffers around core areas. Otherwise, choose bigger rather than smaller areas; (5) provide for connectivity at a wide range of dispersal distances (within and between patches), emphasising distances <20-30 km; and (6) use a portfolio of approaches, including but not limited to MPAs. Three case studies illustrating the application of these principles to coral reef management in the Bohol Sea (Philippines), the Great Barrier Reef (Australia) and Kimbe Bay (Papua New

  1. Future reef decalcification under a business-as-usual CO2 emission scenario.

    PubMed

    Dove, Sophie G; Kline, David I; Pantos, Olga; Angly, Florent E; Tyson, Gene W; Hoegh-Guldberg, Ove

    2013-09-17

    Increasing atmospheric partial pressure of CO2 (pCO2) is a major threat to coral reefs, but some argue that the threat is mitigated by factors such as the variability in the response of coral calcification to acidification, differences in bleaching susceptibility, and the potential for rapid adaptation to anthropogenic warming. However the evidence for these mitigating factors tends to involve experimental studies on corals, as opposed to coral reefs, and rarely includes the influence of multiple variables (e.g., temperature and acidification) within regimes that include diurnal and seasonal variability. Here, we demonstrate that the inclusion of all these factors results in the decalcification of patch-reefs under business-as-usual scenarios and reduced, although positive, calcification under reduced-emission scenarios. Primary productivity was found to remain constant across all scenarios, despite significant bleaching and coral mortality under both future scenarios. Daylight calcification decreased and nocturnal decalcification increased sharply from the preindustrial and control conditions to the future scenarios of low (reduced emissions) and high (business-as-usual) increases in pCO2. These changes coincided with deeply negative carbonate budgets, a shift toward smaller carbonate sediments, and an increase in the abundance of sediment microbes under the business-as-usual emission scenario. Experimental coral reefs demonstrated highest net calcification rates and lowest rates of coral mortality under preindustrial conditions, suggesting that reef processes may not have been able to keep pace with the relatively minor environmental changes that have occurred during the last century. Taken together, our results have serious implications for the future of coral reefs under business-as-usual environmental changes projected for the coming decades and century.

  2. Patch shape, connectivity, and foraging by oldfield mice (Peromyscus polionotus).

    SciTech Connect

    Orrock, John, L.; Danielson, Brent J

    2005-06-01

    We examined how corridors and patch shape affect foraging by the oldfield mouse (Peromyscus polionotus) by deploying foraging trays and live traps in experimental landscapes with 3 different patch types: patches connected with a corridor, unconnected patches with projecting corridorlike portions (winged patches), and unconnected rectangular patches. Corridors did not lead to different levels of activity of P. polionotus among the 3 patch types. Rather, corridors influenced activity by changing patch shape: foraging in seed trays and total number of captures of P. polionotus tended to be greater at the patch center than at the patch edge, but only in connected and winged patches where corridors or wings increased the amount of patch edge relative to the amount of core habitat in the patch. P. polionotus avoided open microhabitats near the patch edge in winged and connected patches, but not open microhabitats near the patch interior, suggesting that predation risk caused shifts in foraging near edges in connected and winged patches. Foraging in corridors and wings was generally low, suggesting that both are high-risk habitats where predation risk is not ameliorated by proximity to vegetative cover. By changing patch shape, corridors caused changes in within-patch activity of P. polionotus, changing foraging patterns and potentially altering the dynamics of P. polionotus and the seeds they consume.

  3. Palaeogeography of the Caspian Sea marine Pleistocene

    NASA Astrophysics Data System (ADS)

    Yanina, Tamara; Svitoch, Aleksander; Makshaev, Radik; Khomchenko, Denis

    2016-04-01

    Vertical succession of the fossil molluscs of Didacna genus along the Pleistocene sequence of the Caspian Sea area allows for detailed subdivision of the sediments. Zone, i.e. the Caspian Sea Pleistocene, is the highest stratigraphical unit of the regional Quaternary stratigraphic scale. It corresponds to the biozone of Didacna Eichwald subgenus. Based on the fossil groups of Didacna molluscs, the deposits are subdivided into the Baku, Urundzhik-Singil', lower and upper Khazarian, Khvalinian, and post-Khvalinian horizons. Further subdision is based on the changes in Didacna assemblages. Three big transgressive epochs are distinguished in the Pleistocene history of the Caspian Sea that were separated by deep and long regressions. These are the Baku, early Khazarian and Khvalinian transgressions. In transgressive sea basins, the sea level reached the height of 40-50 m and was regulated by the outflow of the Caspian waters into the Black Sea via the Manych depression. The areas of transgressive basins were similar. At the Caucasian coast, the extent of the Baku and early Khazarian transgressions exceeded that of the Khvalinian transgression, while in the Northern Caspian Sea Region the latter was slightly more extensive than the preceding ones. The Urundzhik, late Khazarian and New Caspian transgressions represented sea-level rise of lower rank. All of them were recorded within big regressive epochs being usually related to warm (interglacial) climatic conditions: Singil' (Likhvin), Mikulino and Holocene, respectively. Like at present, the Pleistocene Caspian Sea represented a self-regulating system. Maximal extent of ancient sea basins was dependent upon the height of the Manych sill (that was the main regulating factor), the amount of precipitation, river runoff, and decrease in evaporation. Minimal extent of the sea basin was dependent upon the area and capacity of its southern and middle depressions. At the same time, the rest states (extents) of the Caspian Sea

  4. Predator density and timing of arrival affect reef fish community assembly.

    PubMed

    Stier, Adrian C; Geange, Shane W; Hanson, Kate M; Bolker, Benjamin M

    2013-05-01

    Most empirical studies of predation use simple experimental approaches to quantify the effects of predators on prey (e.g., using constant densities of predators, such as ambient vs. zero). However, predator densities vary in time, and these effects may not be well represented by studies that use constant predator densities. Although studies have independently examined the importance of predator density, temporal variability, and timing of arrival (i.e., early or late relative to prey), the relative contribution of these different predator regimes on prey abundance, diversity, and composition remains poorly understood. The hawkfish (Paracirrhites arcatus), a carnivorous coral reef fish, exhibits substantial variability in patch occupancy, density, and timing of arrival to natural reefs. Our field experiments demonstrated that effects of hawkfish on prey abundance depended on both hawkfish density and the timing of their arrival, but not on variability in hawkfish density. Relative to treatments without hawkfish, hawkfish presence reduced prey abundance by 50%. This effect increased with a doubling of hawkfish density (an additional 33% reduction), and when hawkfish arrived later during community development (a 34% reduction). Hawkfish did not affect within-patch diversity (species richness), but they increased between-patch diversity (beta) based on species incidence (22%), and caused shifts in species composition. Our results suggest that the timing of predator arrival can be as important as predator density in modifying prey abundance and community composition.

  5. Electrostatic patch potentials in Casimir force measurements

    NASA Astrophysics Data System (ADS)

    Garrett, Joseph; Somers, David; Munday, Jeremy

    2015-03-01

    Measurements of the Casimir force require the elimination of the electrostatic force between interacting surfaces. The force can be minimized by applying a potential to one of the two surfaces. However, electrostatic patch potentials remain and contribute an additional force which can obscure the Casimir force signal. We will discuss recent measurements of patch potentials made with Heterodyne Amplitude-Modulated Kelvin Probe Force Microscopy that suggest patches could be responsible for >1% of the signal in some Casimir force measurements, and thus make the distinction between different theoretical models of the Casimir force (e.g. a Drude-model or a plasma-model for the dielectric response) difficult to discern.

  6. 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...

  7. The future of coral reefs

    NASA Astrophysics Data System (ADS)

    Knowlton, Nancy

    2001-05-01

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

  8. The future of coral reefs.

    PubMed

    Knowlton, N

    2001-05-08

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

  9. Bioindication in coral reef ecosystems.

    PubMed

    Yap, H T

    1986-01-01

    The concept of bioindication in the sense of the use of organisms for detecting environmental stress has been employed in coral reef conservation and management for the past several years. Important tools are coral growth rates and various community parameters, notably hard coral cover. The present need is the optimal coordination of international efforts for the earliest possible institution of an effective monitoring system.

  10. Identification and prevalence of coral diseases on three Western Indian Ocean coral reefs.

    PubMed

    Séré, Mathieu G; Chabanet, Pascale; Turquet, Jean; Quod, Jean-Pascal; Schleyer, Michael H

    2015-06-03

    Coral diseases have caused a substantial decline in the biodiversity and abundance of reef-building corals. To date, more than 30 distinct diseases of scleractinian corals have been reported, which cause progressive tissue loss and/or affect coral growth, reproductive capacity, recruitment, species diversity and the abundance of reef-associated organisms. While coral disease research has increased over the last 4 decades, very little is known about coral diseases in the Western Indian Ocean. Surveys conducted at multiple sites in Reunion, South Africa and Mayotte between August 2010 and June 2012 revealed the presence of 6 main coral diseases: black band disease (BBD), white syndrome (WS), pink line syndrome (PLS), growth anomalies (GA), skeleton eroding band (SEB) and Porites white patch syndrome (PWPS). Overall, disease prevalence was higher in Reunion (7.5 ± 2.2%; mean ± SE) compared to South Africa (3.9 ± 0.8%) and Mayotte (2.7 ± 0.3%). Across locations, Acropora and Porites were the genera most susceptible to disease. Spatial variability was detected in both Reunion and South Africa, with BBD and WS more prevalent on shallow than deep reefs. There was also evidence of seasonality in 2 diseases: the prevalence of BBD and WS was higher in summer than winter. This was the first study to investigate the ecology of coral diseases, providing both qualitative and quantitative data, on Western Indian Ocean reefs, and surveys should be expanded to confirm these patterns.

  11. Long-term cleaner fish presence affects growth of a coral reef fish

    PubMed Central

    Clague, Gillian E.; Cheney, Karen L.; Goldizen, Anne W.; McCormick, Mark I.; Waldie, Peter A.; Grutter, Alexandra S.

    2011-01-01

    Cleaning behaviour is considered to be a classical example of mutualism. However, no studies, to our knowledge, have measured the benefits to clients in terms of growth. In the longest experimental study of its kind, over an 8 year period, cleaner fish Labroides dimidiatus were consistently removed from seven patch reefs (61–285 m2) and left undisturbed on nine control reefs, and the growth and parasite load of the damselfish Pomacentrus moluccensis determined. After 8 years, growth was reduced and parasitic copepod abundance was higher on fish from removal reefs compared with controls, but only in larger individuals. Behavioural observations revealed that P. moluccensis cleaned by L. dimidiatus were 27 per cent larger than nearby conspecifics. The selective cleaning by L. dimidiatus probably explains why only larger P. moluccensis individuals benefited from cleaning. This is the first demonstration, to our knowledge, that cleaners affect the growth rate of client individuals; a greater size for a given age should result in increased fecundity at a given time. The effect of the removal of so few small fish on the size of another fish species is unprecedented on coral reefs. PMID:21733872

  12. Aragonite saturation states and nutrient fluxes in coral reef sediments in Biscayne National Park, FL, USA

    USGS Publications Warehouse

    Lisle, John T.; Reich, Christopher D.; Halley, Robert B.

    2014-01-01

    Some coral reefs, such as patch reefs along the Florida Keys reef tract, are not showing significant reductions in calcification rates in response to ocean acidification. It has been hypothesized that this recalcitrance is due to local buffering effects from biogeochemical processes driven by seagrasses. We investigated the influence that pore water nutrients, dissolved inorganic carbon (DIC) and total alkalinity (TA) have on aragonite saturation states (Ωaragonite) in the sediments and waters overlying the sediment surfaces of sand halos and seagrass beds that encircle Alinas and Anniversary reefs in Biscayne National Park. Throughout the sampling period, sediment pore waters from both bottom types had lower oxidation/reduction potentials (ORP), with lower pH relative to the sediment surface waters. The majority (86.5%) of flux rates (n = 96) for ΣNOx–, PO43–, NH4+, SiO2, DIC and TA were positive, sometimes contributing significant concentrations of the respective constituents to the sediment surface waters. The Ωaragonite values in the pore waters (range: 0.18 to 4.78) were always lower than those in the overlying waters (2.40 to 4.46), and 52% (n = 48) of the values were aragonite in 75% (n = 16) of the samples, but increased it in the remainder. The elevated fluxes of nutrients, DIC and TA into the sediment–water interface layer negatively alters the suitability of this zone for the settlement and development of calcifying larvae, while enhancing the establishment of algal communities.

  13. 76 FR 82413 - Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-30

    ... Part 622 Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants... Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and... FMP), and Amendment 3 to the FMP for Corals and Reef Associated Plants and Invertebrates of...

  14. Co-occurrence of mylodontid sloths and insights on their potential distributions during the late Pleistocene

    NASA Astrophysics Data System (ADS)

    Varela, Luciano; Fariña, Richard A.

    2016-01-01

    Species distribution models (SDMs) for the last interglacial (LIG), the global last glacial maximum (LGM) and the Holocene climatic optimum (HCO) were generated for three extinct South American Pleistocene mylodontid giant sloths, Glossotherium robustum, Lestodon armatus and Mylodon darwinii. They are recorded co-occurring in some localities including Arroyo del Vizcaíno site (AdV) in Uruguay. Co-occurrence records were studied based on the overlap of their generated areas of potential distributions, and compared with the available biome reconstructions of South America during the LGM to analyze their distribution patterns, ecological requirements and possible interactions between them. Our results suggest that these sloths could have co-existed mainly in the Chaco-Paraná Basin and the plains in the Río de la Plata area. Areas of high suitability were observed for submerged parts of the continental shelf that were exposed during the LGM showing an overall increase in potential habitat compared to the LIG and HCO. This suggests that there was a drastic reduction in total available areas of preferred habitat at the end of the Pleistocene. The co-occurrence of these sloths at the AdV site suggests the presence of vegetation indicative of mainly open, cold to temperate habitats but with mixed patches typical of humid climates.

  15. New evidence for the barrier reef model, Permian Capitan Reef complex, New Mexico

    SciTech Connect

    Kirkland, B.L.; Moore, C.H. Jr. )

    1990-05-01

    Recent paleontologic and petrologic observations suggest that the Capitan Formation was deposited as an organic or ecologic reef that acted as an emergent barrier to incoming wave energy. In outcrops in the Guadalupe Mountains and within Carlsbad Caverns, massive reef boundstone contains a highly diverse assemblage of frame-building and binding organisms. In modern reefs, diversity among frame builders decreases dramatically with depth. Marine cement is abundant in reef boundstone, but limited in back-reef grainstone and packstone. This cementation pattern is similar to that observed in modern emergent barrier reef systems. Based on comparison with modern analogs, these dasycladrominated back-reef sediments and their associated biota are indicative of shallow, hypersaline conditions. Few of these dasyclads exhibit broken or abraded segments and some thallus sections are still articulated suggesting that low-energy, hypersaline conditions occurred immediately shelfward of the reef. In addition, large-scale topographic features, such as possible spur and groove structures between Walnut Canyon and Rattlesnake Canyon, and facies geometries, such as the reef to shelf transition, resemble those found in modern shallow-water reefs. The organisms that formed the Capitan Reef appear to have lived in, and responded to, physical and chemical conditions similar to those that control the geometry of modern shallow-water reefs. Like their modern counterparts, they seem to have strongly influenced adjacent environments. In light of this evidence, consideration should be given to either modifying or abandoning the marginal mound model in favor of the originally proposed barrier reef model.

  16. Biological models for Mesozoic reef evolution

    SciTech Connect

    Kauffman, E.G. )

    1990-11-01

    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.

  17. Battelle developing reefs to ease habitat losses

    SciTech Connect

    Not Available

    1993-04-01

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

  18. Environmental contamination associated with a marine landfill ('seafill') beside a coral reef.

    PubMed

    Jones, Ross

    2010-11-01

    In Bermuda, bulk waste such as scrap metal, cars, etc., and blocks of cement-stabilized incinerator ash (produced from burning garbage) are disposed of in a foreshore reclamation site, i.e., a seafill. Chemical analyses show that seawater leaching out of the dump regularly exceeds water quality guidelines for Zn and Cu, and that the surrounding sediments are enriched in multiple contaminant classes (metals, polycyclic aromatic hydrocarbons, petroleum hydrocarbons, dioxins and furans, polychlorinated biphenyls and an organochlorine pesticide), i.e., there is a halo of contamination. When compared against biological effects-based sediment quality guidelines (SQGs), numerous sediment samples exceeded the low-range values (where biological effects become possible), and for Hg and Zn exceeded the mid-range value (where they become probable). A few metres away from the edge of the 25 acre dump lies a small coral patch reef, proposed here as most contaminated coral reef in the world.

  19. Scattering from arbitrarily shaped microstrip patch antennas

    NASA Technical Reports Server (NTRS)

    Shively, David G.; Deshpande, Manohar D.; Cockrell, Capers R.

    1992-01-01

    The scattering properties of arbitrarily shaped microstrip patch antennas are examined. The electric field integral equation for a current element on a grounded dielectric slab is developed for a rectangular geometry based on Galerkin's technique with subdomain rooftop basis functions. A shape function is introduced that allows a rectangular grid approximation to the arbitrarily shaped patch. The incident field on the patch is expressed as a function of incidence angle theta(i), phi(i). The resulting system of equations is then solved for the unknown current modes on the patch, and the electromagnetic scattering is calculated for a given angle. Comparisons are made with other calculated results as well as with measurements.

  20. Can Stem Cell 'Patch' Help Heart Failure?

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_164475.html Can Stem Cell 'Patch' Help Heart Failure? Small improvement seen over ... Scientists report another step in the use of stem cells to help treat people with debilitating heart failure. ...

  1. Functional traits of two co-occurring sea urchins across a barren/forest patch system

    NASA Astrophysics Data System (ADS)

    Agnetta, D.; Bonaviri, C.; Badalamenti, F.; Scianna, C.; Vizzini, S.; Gianguzza, P.

    2013-02-01

    Temperate rocky reefs may occur in two alternative states (coralline barrens and erect algal forests), whose formation and maintenance are often determined by sea urchin grazing. The two sea urchin species Paracentrotus lividus and Arbacia lixula are considered to play a similar ecological role despite their differing morphological traits and diets. The patchy mosaic areas of Ustica Island, Italy, offer an ideal environment in which to study differences in the performance of P. lividus and A. lixula in barren versus forest states. Results show that the two sea urchin species differ in diet, trophic position, grazing adaptation, movement ability and fitness in both barren and forest patches. We confirmed herbivory in P. lividus and omnivory with a strong tendency to carnivory in A. lixula. When the sea urchin escape response to a predator was triggered, P. lividus responded faster in barren and forest patches. Forest patch restricted movement, especially in A. lixula (velocity in barren ≈ 10-fold greater than in forest). A large Aristotle's lantern, indicative of durophagy, confirmed adaptation of A. lixula to barren state.

  2. 75 FR 48934 - Coral Reef Conservation Program Implementation Guidelines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-12

    ... National Oceanic and Atmospheric Administration RIN 0648-ZC19 Coral Reef Conservation Program... Implementation Guidelines for the Coral Reef Conservation Program. SUMMARY: This document provides NOAA's revised Grant Program Implementation Guidelines (Guidelines) for the Coral Reef Conservation Program (CRCP...

  3. Management of prosthetic patch infection after CEA.

    PubMed

    Naylor, Ross

    2016-04-01

    It has been reported that 0.5-1% of patients undergoing carotid endarterectomy with prosthetic patch closure of the arteriotomy will develop patch infection. One third occur within the first 2 months after surgery, while two-thirds occur after >6 months have elapsed. Wound infection and abscess formation is the commonest mode of presentation in early cases, while chronic sinus discharge and false aneurysm formation are the commonest presentations in late cases. The commonest infecting organisms are Staphylococci/Streptococci (90%) and this should be borne in mind when planning antibiotic therapy before cultures are available. Most patch infections present (semi)-electively and patch rupture is relatively rare (10%), thereby enabling the surgeon to undertake careful evaluation of the patients overall clinical and anatomical status, whilst planning the optimal treatment strategy. If necessary, the patient should be transferred to a tertiary center for treatment. This is not an operation to be undertaken by an inexperienced surgeon. Operative planning should involve checking the original operation note (did the patient tolerate carotid clamping under locoregional anesthesia and therefore might tolerate carotid ligation), is there evidence of contralateral cranial nerve lesions (a contraindication to major open surgery) and has the surgeon planned for adequate distal exposure of the internal carotid artery. Patch excision and autologous reconstruction (usually vein) is the current 'gold standard' treatment, but highly selected patients can be successfully treated by less invasive surgery (including insertion of a covered stent). Patch excision and prosthetic reconstruction should be avoided.

  4. Patch-clamp amplifiers on a chip.

    PubMed

    Weerakoon, Pujitha; Culurciello, Eugenio; Yang, Youshan; Santos-Sacchi, Joseph; Kindlmann, Peter J; Sigworth, Fred J

    2010-10-15

    We present the first, fully integrated, two-channel implementation of a patch-clamp measurement system. With this "PatchChip" two simultaneous whole-cell recordings can be obtained with rms noise of 8pA in a 10kHz bandwidth. The capacitance and series-resistance of the electrode can be compensated up to 10pF and 100MΩ respectively under computer control. Recordings of hERG and Na(v) 1.7 currents demonstrate the system's capabilities, which are on par with large, commercial patch-clamp instrumentation. By reducing patch-clamp amplifiers to a millimeter size micro-chip, this work paves the way to the realization of massively parallel, high-throughput patch-clamp systems for drug screening and ion-channel research. The PatchChip is implemented in a 0.5μm silicon-on-sapphire process; its size is 3×3mm(2) and the power consumption is 5mW per channel with a 3.3V power supply.

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

    PubMed

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

    2015-01-01

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

  6. Episodes of reef growth at Lord Howe Island, the southernmost reef in the southwest Pacific

    NASA Astrophysics Data System (ADS)

    Woodroffe, C. D.; Dickson, M. E.; Brooke, B. P.; Kennedy, D. M.

    2005-12-01

    Lord Howe Island lies at the present latitudinal limit to reef growth in the Pacific and preserves evidence of episodes of reef development over the Late Quaternary. A modern fringing reef flanks the western shore of Lord Howe Island, enclosing a Holocene lagoon, and Late Quaternary eolianites veneer the island. Coral-bearing beach and shallow-water calcarenites record a sea level around 2-3 m above present during the Last Interglacial. No reefs or subaerial carbonate deposits occur on, or around, Balls Pyramid, 25 km to the south. The results of chronostratigraphic studies of the modern Lord Howe Island reef and lagoon indicate prolific coral production during the mid-Holocene, but less extensive coral cover during the late Holocene. Whereas the prolific mid-Holocene reefs might appear to reflect warmer sea-surface temperatures, the pattern of dates and reef growth history are similar to those throughout the Great Barrier Reef and across much of the Indo-Pacific and are more likely correlated with availability of suitable substrate. Little direct evidence of a Last Interglacial reef is now preserved, and the only evidence for older periods of reef establishment comes from clasts of coral in a well-cemented limestone unit below a coral that has been dated to the Last Interglacial age in a core at the jetty. However, a massive reef structure occurs near the centre of the wide shelf around Lord Howe Island, veneered with Holocene coralline algae. Its base is 40-50 m deep and it rises to water depths of less than 30 m. This fossil reef is several times more extensive than either Holocene or Last Interglacial reefs appear to have been. Holocene give-up reef growth is inferred during the postglacial transgression, but an alternative interpretation is that this is a much older landform, indicating reefs that were much more extensive than modern reefs at this marginal site.

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

    PubMed

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

    2015-06-05

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

  8. Short-term monocular patching boosts the patched eye’s response in visual cortex

    PubMed Central

    Zhou, Jiawei; Baker, Daniel H.; Simard, Mathieu; Saint-Amour, Dave; Hess, Robert F.

    2015-01-01

    Abstract Purpose: Several recent studies have demonstrated that following short-term monocular deprivation in normal adults, the patched eye, rather than the unpatched eye, becomes stronger in subsequent binocular viewing. However, little is known about the site and nature of the underlying processes. In this study, we examine the underlying mechanisms by measuring steady-state visual evoked potentials (SSVEPs) as an index of the neural contrast response in early visual areas. Methods: The experiment consisted of three consecutive stages: a pre-patching EEG recording (14 minutes), a monocular patching stage (2.5 hours) and a post-patching EEG recording (14 minutes; started immediately after the removal of the patch). During the patching stage, a diffuser (transmits light but not pattern) was placed in front of one randomly selected eye. During the EEG recording stage, contrast response functions for each eye were measured. Results: The neural responses from the patched eye increased after the removal of the patch, whilst the responses from the unpatched eye remained the same. Such phenomena occurred under both monocular and dichoptic viewing conditions. Conclusions: We interpret this eye dominance plasticity in adult human visual cortex as homeostatic intrinsic plasticity regulated by an increase of contrast-gain in the patched eye. PMID:26410580

  9. Multi-scale interactions between local hydrography, seabed topography, and community assembly on cold-water coral reefs

    NASA Astrophysics Data System (ADS)

    Henry, L.-A.; Moreno Navas, J.; Roberts, J. M.

    2013-04-01

    We investigated how interactions between hydrography, topography and species ecology influence the assembly of species and functional traits across multiple spatial scales of a cold-water coral reef seascape. In a novel approach for these ecosystems, we used a spatially resolved complex three-dimensional flow model of hydrography to help explain assembly patterns. Forward-selection of distance-based Moran's eigenvector mapping (dbMEM) variables identified two submodels of spatial scales at which communities change: broad-scale (across reef) and fine-scale (within reef). Variance partitioning identified bathymetric and hydrographic gradients important in creating broad-scale assembly of species and traits. In contrast, fine-scale assembly was related more to processes that created spatially autocorrelated patches of fauna, such as philopatric recruitment in sessile fauna, and social interactions and food supply in scavenging detritivores and mobile predators. Our study shows how habitat modification of reef connectivity and hydrography by bottom fishing and renewable energy installations could alter the structure and function of an entire cold-water coral reef seascape.

  10. Dynamic fragility of oceanic coral reef ecosystems

    PubMed Central

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

    2006-01-01

    As one of the most diverse and productive ecosystems known, and one of the first ecosystems to exhibit major climate-warming impacts (coral bleaching), coral reefs have drawn much scientific attention to what may prove to be their Achilles heel, the thermal sensitivity of reef-building corals. Here we show that climate change-driven loss of live coral, and ultimately structural complexity, in the Seychelles results in local extinctions, substantial reductions in species richness, reduced taxonomic distinctness, and a loss of species within key functional groups of reef fish. The importance of deteriorating physical structure to these patterns demonstrates the longer-term impacts of bleaching on reefs and raises questions over the potential for recovery. We suggest that isolated reef systems may be more susceptible to climate change, despite escaping many of the stressors impacting continental reefs. PMID:16709673

  11. Astronaut Photography of Coral Reefs

    NASA Technical Reports Server (NTRS)

    Robinson, Julie A.; Noordeloos, Marco

    2001-01-01

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

  12. 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...

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

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

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

  14. Oxfordian reef architecture of the La Manga Formation, Neuquén Basin, Mendoza Province, Argentina

    NASA Astrophysics Data System (ADS)

    Palma, Ricardo M.; Kietzmann, Diego A.; Adamonis, Susana; Gómez, José López

    2009-11-01

    The Neuquén back-arc basin is located on the west margin of the South American platform between latitudes 36° and 40° S. The basin is famous for its continuous sedimentary record from the Late Triassic to Cenozoic comprising continental and marine clastic, carbonate, and evaporitic deposits up to 2.600 m in thickness. The stratigraphical and paleontological studies of the outcrops of the La Manga Formation, Argentina, located near the Bardas Blancas region, Mendoza province (35° S and 69° O) allow the reconstruction of the sedimentary environments of an Oxfordian carbonate ramp, where outer ramp, middle ramp, inner ramp (oolitic shoal), inner ramp margin (patch reef) lagoon and paleokarst were differentiated. The reefs consist of back reef facies and insitu framework of coral boundstones that was formed at the top of shallowing-upward succession. Coral reefs were analyzed by defining coral colonies shapes, paleontological content, coral diversity and taphonomy studies. In some studied sections abundant fragments of gryphaeids, encrusting bryozoans, and isolated sponges provided a suitable substrate for coral colonization; however, other sections show an increase in the proportions of ooids, peloidal and coral intraclasts. The core reef facies is composed of white-grey unstratified and low diversity scleractinian coral limestone dominated by robust and thinly branching corals with cerioid-phocoid growths and massive coral colonies with meandroid-thamnasteroid growth forms. The assemblage is characterized by Actinastraea sp., Australoseris sp., Thamnasteria sp. and Garateastrea sp. Internal facies organization and different types of coral colonies allow to recognize the development of varying framework as well as intercolony areas. A superstratal growth fabric characterizes the coral assemblage. On the basis of coral growth fabric (branche and domal types), the reef of La Manga Formation is considered a typical mixstones. The intercolony areas consist of

  15. The role of sponges in the Mesoamerican Barrier-Reef Ecosystem, Belize.

    PubMed

    Rützler, Klaus

    2012-01-01

    Over the past four decades, sponge research has advanced by leaps and bounds through endeavours such as the Caribbean Coral Reef Ecosystems (CCRE) programme at the U.S. National Museum of Natural History in Washington, D.C. Since its founding in the early 1970s, the programme has been dedicated to a detailed multidisciplinary study of a section of the Mesoamerican Barrier Reef, the Atlantic's largest reef complex, and has generated data far beyond the capability of lone investigators and brief expeditions. This reef complex extends 250 km southward from Yucatan, Mexico, into the Gulf of Honduras, most of it lying 20-40 km off the coast of Belize. A relatively unspoiled ecosystem, it features a great variety of habitats in close proximity, ranging from mangrove islands, seagrass meadows, and patch reefs in its lagoon to the barrier reef along the margin of the continental shelf. Among its varied macrobenthos, sponges stand out for their ubiquity, range of colours, rich species and biomass, and ecological importance; they populate rocky substrates, some sandy bottoms, and the subtidal stilt roots and peat banks of mangroves. Working from a field station established in 1972 on Carrie Bow Cay, a sand islet atop the reef off southern Belize, experts in numerous disciplines from both the Museum and academic institutions throughout the world have explored the area's biodiversity in the broadest sense and community development over time. At last count, 113 researchers (88 working on site) have focused on the biological and geological role of Porifera in Carrie Bow's reef communities, with the results reported in 125 scientific papers to date. The majority of these sponge studies have centred on systematics and faunistics, including quantitative distribution among the various habitats. Taxonomic approaches have ranged from basic morphology to fine structure, DNA barcoding, and ecological manipulations and culminated in a mini-workshop involving several experts on Caribbean

  16. The MICROBE (Microcosm Investigation of Carbonate Reef/Ocean Microbial Biogeochemistry & Ecology) Project

    NASA Astrophysics Data System (ADS)

    Hannides, A. K.; Gaidos, E. J.; Sansone, F. J.

    2003-12-01

    We present a methodology to manipulate carbonate reef sediments in order to study the geochemical and microbiological response of reef systems to perturbations. We specifically plan to study the effects of changes in the atmospheric partial pressure of CO2. Our laboratory set-up will consist of cores containing carbonate reef sediments and overlying water. These microcosms are designed to replicate the gross hydraulic and geochemical characteristics of sediments in a natural tropical reef patch. This is achieved by reproducing the advective transport of water and particulates in and out of the sediments induced by tides and surface waves. Seawater from nearby reefs is to be introduced into the cores with reversible peristaltic pumps. The pumps will vary the overlying water column and simulate the changes in hydrostatic head that accompany waves and tides. The parameters characterizing these oscillations will be set at values reflecting those at nearby natural settings. Sediment column characteristics will be determined non-destructively through openings at various depths down the sediment cores. These openings are fitted with rubber septa and shut-off valves, which allow gas-tight sampling of porewaters. An additional set of openings allows for the removal of small amounts of sediments using augers. Our porewater analyses will include dissolved O2, CO2, CH4 and alkalinity, ammonium, sulfide, and iron and manganese ions. Our solid phase analyses will include carbonate composition and framework structure, and iron and manganese abundances in the carbonate phases. We will measure microbial abundance in porewater and the sediment particles by DAPI cell counts and will assay community composition using Denaturing Gradient Gel Electrophoresis (DGGE). Our goal is to use this methodology to observe and record carbonate precipitation and dissolution by microbiota under varying carbon dioxide regimes. pCO2 concentrations will be manipulated by bubbling a N2/CO2 mixture

  17. Habitat heterogeneity reflected in mesophotic reef sediments

    NASA Astrophysics Data System (ADS)

    Weinstein, D. K.; Klaus, J. S.; Smith, T. B.

    2015-11-01

    Modern reef sediments reflect the physical and chemical characteristics of the environment as well as the local reef fauna. Analysis of sedimentary reef facies can thus provide a powerful tool in interpreting ancient reef deposits. However, few studies have attempted to differentiate sedimentary facies in mesophotic coral ecosystems, low light habitats defined as residing 30-150 m below sea level. The low-angle shelf mesophotic coral ecosystem south of the northern U.S. Virgin Islands (USVI) consists of reefs with different structural characteristics ideal for studying the relationship between habitat variability and sedimentary facies. Textural, compositional, and geochemical analyses of surface sediments were used to identify mesophotic reef subfacies associated with distinct benthic communities and structural habitats. Sediment grain composition and bulk geochemistry were found to broadly record the distribution and abundance of coral and macroalgae communities, foundational mesophotic reef benthic organisms. Overall, sediment composition was found to be a good indicator of specific reef environments in low-angle mesophotic reef habitats. Sedimentological analyses indicate that hydrodynamic forces do not transport a significant amount of allochthonous sediment or potentially harmful terrigenous material to USVI mesophotic reefs. Episodic, maximum current velocities prevented deposition of most silt-size grains and smaller, but biological processes were found to have a greater influence on subfacies partitioning than hydrodynamic processes. Results provide a new analog for studies of ancient mesophotic coral ecosystem geological history and document the relationship between mesophotic reef subfacies, structural complexity, and habitat heterogeneity. They also demonstrate how mesophotic reefs along the same shelf system do not always share similar sedimentary characteristics and thus record a diverse set of ecological and environmental conditions.

  18. Onondage pinnacle reefs in New York State

    SciTech Connect

    Friedman, G.M.

    1995-09-01

    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.

  19. Geological Approaches to Coral Reef Ecology

    NASA Astrophysics Data System (ADS)

    Kench, Paul

    2008-09-01

    Tropical coral reef systems cover an estimated 284,300 square kilometers of the Earth's surface and are considered among the most valuable ecosystems on Earth. The reef systems are zones of high biological diversity, habitat for about one quarter of all known marine species, and important components of the global carbon cycle. In addition, they provide the physical foundation for a number of mid-ocean nation states. Coral reefs worldwide are considered to be in serious ecological decline due to anthropogenic impacts, natural stresses, and climate change. However, these gloomy projections for coral reefs are based largely on analysis of short-term changes in their ecological condition.

  20. Studies on the Great Barrier Reef

    SciTech Connect

    Walton, S.

    1985-01-01

    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.

  1. Individual colour patches as multicomponent signals.

    PubMed

    Grether, Gregory F; Kolluru, Gita R; Nersissian, Karen

    2004-08-01

    Colour patches are complex traits, the components of which may evolve independently through a variety of mechanisms. Although usually treated as simple, two-dimensional characters and classified as either structural or pigmentary, in reality colour patches are complicated, three-dimensional structures that often contain multiple pigment types and structural features. The basic dermal chromatophore unit of fishes, reptiles and amphibians consists of three contiguous cell layers. Xanthophores and erythrophores in the outermost layer contain carotenoid and pteridine pigments that absorb short-wave light; iridophores in the middle layer contain crystalline platelets that reflect light back through the xanthophores; and melanophores in the basal layer contain melanins that absorb light across the spectrum. Changes in any one component of a chromatophore unit can drastically alter the reflectance spectrum produced, and for any given adaptive outcome (e.g. an increase in visibility), there may be multiple biochemical or cellular routes that evolution could take, allowing for divergent responses by different populations or species to similar selection regimes. All of the mechanisms of signal evolution that previously have been applied to single ornaments (including whole colour patches) could potentially be applied to the individual components of colour patches. To reach a complete understanding of colour patch evolution, however, it may be necessary to take an explicitly multi-trait approach. Here, we review multiple trait evolution theory and the basic mechanisms of colour production in fishes, reptiles and amphibians, and use a combination of computer simulations and empirical examples to show how multiple trait evolution theory can be applied to the components of single colour patches. This integrative perspective on animal colouration opens up a host of new questions and hypotheses. We offer specific, testable functional hypotheses for the most common pigmentary

  2. Late Pleistocene dune activity in the central Great Plains, USA

    USGS Publications Warehouse

    Mason, J.A.; Swinehart, J.B.; Hanson, P.R.; Loope, D.B.; Goble, R.J.; Miao, X.; Schmeisser, R.L.

    2011-01-01

    Stabilized dunes of the central Great Plains, especially the megabarchans and large barchanoid ridges of the Nebraska Sand Hills, provide dramatic evidence of late Quaternary environmental change. Episodic Holocene dune activity in this region is now well-documented, but Late Pleistocene dune mobility has remained poorly documented, despite early interpretations of the Sand Hills dunes as Pleistocene relicts. New optically stimulated luminescence (OSL) ages from drill cores and outcrops provide evidence of Late Pleistocene dune activity at sites distributed across the central Great Plains. In addition, Late Pleistocene eolian sands deposited at 20-25 ka are interbedded with loess south of the Sand Hills. Several of the large dunes sampled in the Sand Hills clearly contain a substantial core of Late Pleistocene sand; thus, they had developed by the Late Pleistocene and were fully mobile at that time, although substantial sand deposition and extensive longitudinal dune construction occurred during the Holocene. Many of the Late Pleistocene OSL ages fall between 17 and 14 ka, but it is likely that these ages represent only the later part of a longer period of dune construction and migration. At several sites, significant Late Pleistocene or Holocene large-dune migration also probably occurred after the time represented by the Pleistocene OSL ages. Sedimentary structures in Late Pleistocene eolian sand and the forms of large dunes potentially constructed in the Late Pleistocene both indicate sand transport dominated by northerly to westerly winds, consistent with Late Pleistocene loess transport directions. Numerical modeling of the climate of the Last Glacial Maximum has often yielded mean monthly surface winds southwest of the Laurentide Ice Sheet that are consistent with this geologic evidence, despite strengthened anticyclonic circulation over the ice sheet. Mobility of large dunes during the Late Pleistocene on the central Great Plains may have been the result of

  3. Bryozoa of Floridan Oculina reefs.

    PubMed

    Winston, Judith E

    2016-01-27

    The deep-water Oculina coral reefs on the continental shelf off the east central coast of Florida are a unique protected marine habitat. A complete inventory of the Oculina-associated fauna is important to support its conservation. This paper provides an inventory of the bryozoans of the Oculina reef area. Unusually, the bryozoan fauna is dominated by encrusting cribrilinid bryozoans. These include two new species of Puellina and three other Floridan-Atlantic shelf Puellina only recently described. Additional cribrilinid species belong to the genera Klugerella and Rosulapelta. Other bryozoans found in the habitat include 38 encrusting cheilostome species, six of them new to science, belonging to the genera Callopora, Parasmittina, Parasmittina, Smittina, Microporella and Stephanollona. Cyclostomes were only sparsely represented, comprising three encrusting taxa.

  4. Lethal interpersonal violence in the Middle Pleistocene.

    PubMed

    Sala, Nohemi; Arsuaga, Juan Luis; Pantoja-Pérez, Ana; Pablos, Adrián; Martínez, Ignacio; Quam, Rolf M; Gómez-Olivencia, Asier; Bermúdez de Castro, José María; Carbonell, Eudald

    2015-01-01

    Evidence of interpersonal violence has been documented previously in Pleistocene members of the genus Homo, but only very rarely has this been posited as the possible manner of death. Here we report the earliest evidence of lethal interpersonal violence in the hominin fossil record. Cranium 17 recovered from the Sima de los Huesos Middle Pleistocene site shows two clear perimortem depression fractures on the frontal bone, interpreted as being produced by two episodes of localized blunt force trauma. The type of injuries, their location, the strong similarity of the fractures in shape and size, and the different orientations and implied trajectories of the two fractures suggest they were produced with the same object in face-to-face interpersonal conflict. Given that either of the two traumatic events was likely lethal, the presence of multiple blows implies an intention to kill. This finding shows that the lethal interpersonal violence is an ancient human behavior and has important implications for the accumulation of bodies at the site, supporting an anthropic origin.

  5. Lethal Interpersonal Violence in the Middle Pleistocene

    PubMed Central

    Sala, Nohemi; Arsuaga, Juan Luis; Pantoja-Pérez, Ana; Pablos, Adrián; Martínez, Ignacio; Quam, Rolf M.; Gómez-Olivencia, Asier; Bermúdez de Castro, José María; Carbonell, Eudald

    2015-01-01

    Evidence of interpersonal violence has been documented previously in Pleistocene members of the genus Homo, but only very rarely has this been posited as the possible manner of death. Here we report the earliest evidence of lethal interpersonal violence in the hominin fossil record. Cranium 17 recovered from the Sima de los Huesos Middle Pleistocene site shows two clear perimortem depression fractures on the frontal bone, interpreted as being produced by two episodes of localized blunt force trauma. The type of injuries, their location, the strong similarity of the fractures in shape and size, and the different orientations and implied trajectories of the two fractures suggest they were produced with the same object in face-to-face interpersonal conflict. Given that either of the two traumatic events was likely lethal, the presence of multiple blows implies an intention to kill. This finding shows that the lethal interpersonal violence is an ancient human behavior and has important implications for the accumulation of bodies at the site, supporting an anthropic origin. PMID:26018668

  6. Methods of Making and Using Shape Memory Polymer Composite Patches

    NASA Technical Reports Server (NTRS)

    Hood, Patrick J.

    2011-01-01

    A method of repairing a composite component having a damaged area including: laying a composite patch over the damaged area: activating the shape memory polymer resin to easily and quickly mold said patch to said damaged area; deactivating said shape memory polymer so that said composite patch retains the molded shape; and bonding said composite patch to said damaged part.

  7. Great Barrier Reef, Queensland, Australia

    NASA Technical Reports Server (NTRS)

    1991-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2001-05-01

    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 resulted from global warming. Coral reefs would submerge by sea level rise in this century. To conserve and manage coral reefs against these threats, monitoring of coral reef by satellite remote sensing is important. ASTER has provided effective data for mapping coral reef landforms and benthic communities. The most basic geomorphological and ecological zonation was successfully classified using ASTER data. For example, coral reef flat with its zonation of algai rim, rubble bank, back reef was clearly identified by ASTER by decision tree method and bottom index using VNIR bands data. For the basis of effective monitoring of coral reefs, we have constructed coral reef remote sensing database, which contains more than 1,100,000 data. Tropical and subtropical oceans (40N-40S) were gridded by 0.5 x 0.5 degrees and the grids with coral reefs were identified. The grids with coral reefs correspond to path/rows of the satellite (MOS1, JERS-1, ADEOS, LANDSAT, SPOT and TERRA) and basic information (existence of data, satellite and sensor, path/row, lat/log, aquisition date, cloud cover, type of coral reef) of so-far obtained satellite data until 2000 was input in the database. Status of data aquisition at specific coral reefs can be listed up by this database.

  9. Influence of reef geometry on wave attenuation on a Brazilian coral reef

    NASA Astrophysics Data System (ADS)

    Costa, Mirella B. S. F.; Araújo, Moacyr; Araújo, Tereza C. M.; Siegle, Eduardo

    2016-01-01

    This study presents data from field experiments that focus on the influence of coral reef geometry on wave transformation in the Metropolitan Area of Recife (MAR) on the northeast coast of Brazil. First, a detailed bathymetric survey was conducted, revealing a submerged reef bank, measuring 18 km long by 1 km wide, parallel to the coastline with a quasi-horizontal top that varies from 0.5 m to 4 m in depth at low tide. Cluster similarity between 180 reef profiles indicates that in 75% of the area, the reef geometry has a configuration similar to a platform reef, whereas in 25% of the area it resembles a fringing reef. Measurements of wave pressure fluctuations were made at two stations (experiments E1 and E2) across the reef profile. The results indicate that wave height was tidally modulated at both experimental sites. Up to 67% (E1) and 99.9% (E2) of the incident wave height is attenuated by the reef top at low tide. This tidal modulation is most apparent at E2 due to reef geometry. At this location, the reef top is only approximately 0.5 m deep during mean low spring water, and almost all incident waves break on the outer reef edge. At E1, the reef top depth is 4 m, and waves with height ratios smaller than the critical breaking limit are free to pass onto the reef and are primarily attenuated by bottom friction. These results highlight the importance of reef geometry in controlling wave characteristics of the MAR beaches and demonstrate its effect on the morphology of the adjacent coast. Implications of differences in wave attenuation and the level of protection provided by the reefs to the adjacent shoreline are discussed.

  10. Living in the past: phylogeography and population histories of Indo-Pacific wrasses (genus Halichoeres) in shallow lagoons versus outer reef slopes.

    PubMed

    Ludt, William B; Bernal, Moisés A; Bowen, Brian W; Rocha, Luiz A

    2012-01-01

    Sea level fluctuations during glacial cycles affect the distribution of shallow marine biota, exposing the continental shelf on a global scale, and displacing coral reef habitat to steep slopes on oceanic islands. In these circumstances we expect that species inhabiting lagoons should show shallow genetic architecture relative to species inhabiting more stable outer reefs. Here we test this expectation on an ocean-basin scale with four wrasses (genus Halichoeres): H. claudia (N = 194, with ocean-wide distribution) and H. ornatissimus (N = 346, a Hawaiian endemic) inhabit seaward reef slopes, whereas H. trimaculatus (N = 239) and H. margaritaceus (N = 118) inhabit lagoons and shallow habitats throughout the Pacific. Two mitochondrial markers (cytochrome oxidase I and control region) were sequenced to resolve population structure and history of each species. Haplotype and nucleotide diversity were similar among all four species. The outer reef species showed significantly less population structure, consistent with longer pelagic larval durations. Mismatch distributions and significant negative Fu's F values indicate Pleistocene population expansion for all species, and (contrary to expectations) shallower histories in the outer slope species. We conclude that lagoonal wrasses may persist through glacial habitat disruptions, but are restricted to refugia during lower sea level stands. In contrast, outer reef slope species have homogeneous and well-connected populations through their entire ranges regardless of sea level fluctuations. These findings contradict the hypothesis that shallow species are less genetically diverse as a consequence of glacial cycles.

  11. Measles vaccination using a microneedle patch.

    PubMed

    Edens, Chris; Collins, Marcus L; Ayers, Jessica; Rota, Paul A; Prausnitz, Mark R

    2013-07-25

    Measles vaccination programs would benefit from delivery methods that decrease cost, simplify logistics, and increase safety. Conventional subcutaneous injection is limited by the need for skilled healthcare professionals to reconstitute and administer injections, and by the need for safe needle handling and disposal to reduce the risk of disease transmission through needle re-use and needlestick injury. Microneedles are micron-scale, solid needles coated with a dry formulation of vaccine that dissolves in the skin within minutes after patch application. By avoiding the use of hypodermic needles, vaccination using a microneedle patch could be carried out by minimally trained personnel with reduced risk of blood-borne disease transmission. The goal of this study was to evaluate measles vaccination using a microneedle patch to address some of the limitations of subcutaneous injection. Viability of vaccine virus dried onto a microneedle patch was stabilized by incorporation of the sugar, trehalose, and loss of viral titer was less than 1 log10(TCID50) after storage for at least 30 days at room temperature. Microneedle patches were then used to immunize cotton rats with the Edmonston-Zagreb measles vaccine strain. Vaccination using microneedles at doses equaling the standard human dose or one-fifth the human dose generated neutralizing antibody levels equivalent to those of a subcutaneous immunization at the same dose. These results show that measles vaccine can be stabilized on microneedles and that vaccine efficiently reconstitutes in vivo to generate a neutralizing antibody response equivalent to that generated by subcutaneous injection.

  12. Transdermal patch drug delivery interactions with exercise.

    PubMed

    Lenz, Thomas L; Gillespie, Nicole

    2011-03-01

    Transdermal drug delivery systems, such as the transdermal patch, continue to be a popular and convenient way to administer medications. There are currently several medications that use a transdermal patch drug delivery system. This article describes the potential untoward side effects of increased drug absorption through the use of a transdermal patch in individuals who exercise or participate in sporting events. Four studies have been reported that demonstrate a significant increase in the plasma concentration of nitroglycerin when individuals exercise compared with rest. Likewise, several case reports and two studies have been conducted that demonstrate nicotine toxicity and increased plasma nicotine while wearing a nicotine patch in individuals who exercise or participate in sporting events compared with rest. Healthcare providers, trainers and coaches should be aware of proper transdermal patch use, especially while exercising, in order to provide needed information to their respective patients and athletes to avoid potential untoward side effects. Particular caution should be given to individuals who participate in an extreme sporting event of long duration. Further research that includes more medications is needed in this area.

  13. Activated Membrane Patches Guide Chemotactic Cell Motility

    PubMed Central

    Hecht, Inbal; Skoge, Monica L.; Charest, Pascale G.; Ben-Jacob, Eshel; Firtel, Richard A.; Loomis, William F.; Levine, Herbert; Rappel, Wouter-Jan

    2011-01-01

    Many eukaryotic cells are able to crawl on surfaces and guide their motility based on environmental cues. These cues are interpreted by signaling systems which couple to cell mechanics; indeed membrane protrusions in crawling cells are often accompanied by activated membrane patches, which are localized areas of increased concentration of one or more signaling components. To determine how these patches are related to cell motion, we examine the spatial localization of RasGTP in chemotaxing Dictyostelium discoideum cells under conditions where the vertical extent of the cell was restricted. Quantitative analyses of the data reveal a high degree of spatial correlation between patches of activated Ras and membrane protrusions. Based on these findings, we formulate a model for amoeboid cell motion that consists of two coupled modules. The first module utilizes a recently developed two-component reaction diffusion model that generates transient and localized areas of elevated concentration of one of the components along the membrane. The activated patches determine the location of membrane protrusions (and overall cell motion) that are computed in the second module, which also takes into account the cortical tension and the availability of protrusion resources. We show that our model is able to produce realistic amoeboid-like motion and that our numerical results are consistent with experimentally observed pseudopod dynamics. Specifically, we show that the commonly observed splitting of pseudopods can result directly from the dynamics of the signaling patches. PMID:21738453

  14. Characterizing the morphology of protein binding patches.

    PubMed

    Malod-Dognin, Noël; Bansal, Achin; Cazals, Frédéric

    2012-12-01

    Let the patch of a partner in a protein complex be the collection of atoms accounting for the interaction. To improve our understanding of the structure-function relationship, we present a patch model decoupling the topological and geometric properties. While the geometry is classically encoded by the atomic positions, the topology is recorded in a graph encoding the relative position of concentric shells partitioning the interface atoms. The topological-geometric duality provides the basis of a generic dynamic programming-based algorithm comparing patches at the shell level, which may favor topological or geometric features. On the biological side, we address four questions, using 249 cocrystallized heterodimers organized in biological families. First, we dissect the morphology of binding patches and show that Nature enjoyed the topological and geometric degrees of freedom independently while retaining a finite set of qualitatively distinct topological signatures. Second, we argue that our shell-based comparison is effective to perform atomic-level comparisons and show that topological similarity is a less stringent than geometric similarity. We also use the topological versus geometric duality to exhibit topo-rigid patches, whose topology (but not geometry) remains stable upon docking. Third, we use our comparison algorithms to infer specificity-related information amidst a database of complexes. Finally, we exhibit a descriptor outperforming its contenders to predict the binding affinities of the affinity benchmark. The softwares developed with this article are availablefrom http://team.inria.fr/abs/vorpatch_compatch/.

  15. Microneedle patches for vaccination in developing countries.

    PubMed

    Arya, Jaya; Prausnitz, Mark R

    2016-10-28

    Millions of people die of infectious diseases each year, mostly in developing countries, which could largely be prevented by the use of vaccines. While immunization rates have risen since the introduction of the Expanded Program on Immunization (EPI), there remain major challenges to more effective vaccination in developing countries. As a possible solution, microneedle patches containing an array of micron-sized needles on an adhesive backing have been developed to be used for vaccine delivery to the skin. These microneedle patches can be easily and painlessly applied by pressing against the skin and, in some designs, do not leave behind sharps waste. The patches are single-dose, do not require reconstitution, are easy to administer, have reduced size to simplify storage, transportation and waste disposal, and offer the possibility of improved vaccine immunogenicity, dose sparing and thermostability. This review summarizes vaccination challenges in developing countries and discusses advantages that microneedle patches offer for vaccination to address these challenges. We conclude that microneedle patches offer a powerful new technology that can enable more effective vaccination in developing countries.

  16. Surface patterning of nanoparticles with polymer patches

    SciTech Connect

    Choueiri, Rachelle M.; Galati, Elizabeth; Thérien-Aubin, Héloïse; Klinkova, Anna; Larin, Egor M.; Querejeta-Fernández, Ana; Han, Lili; Xin, Huolin L.; Gang, Oleg; Zhulina, Ekaterina B.; Rubinstein, Michael; Kumacheva, Eugenia

    2016-08-24

    Patterning of colloidal particles with chemically or topographically distinct surface domains (patches) has attracted intense research interest. Surface-patterned particles act as colloidal analogues of atoms and molecules serve as model systems in studies of phase transitions in liquid systems, behave as ‘colloidal surfactants’ and function as templates for the synthesis of hybrid particles. The generation of micrometre- and submicrometre-sized patchy colloids is now efficient but surface patterning of inorganic colloidal nanoparticles with dimensions of the order of tens of nanometres is uncommon. Such nanoparticles exhibit size- and shape-dependent optical, electronic and magnetic properties, and their assemblies show new collective properties. At present, nanoparticle patterning is limited to the generation of two-patch nanoparticles and nanoparticles with surface ripples or a ‘raspberry’ surface morphology. We demonstrate nanoparticle surface patterning, which utilizes thermodynamically driven segregation of polymer ligands from a uniform polymer brush into surface-pinned micelles following a change in solvent quality. Patch formation is reversible but can be permanently preserved using a photocrosslinking step. The methodology offers the ability to control the dimensions of patches, their spatial distribution and the number of patches per nanoparticle, in agreement with a theoretical model. The versatility of the strategy is demonstrated by patterning nanoparticles with different dimensions, shapes and compositions, tethered with various types of polymers and subjected to different external stimuli. Furthermore, these patchy nanocolloids have potential applications in fundamental research, the self-assembly of nanomaterials, diagnostics, sensing and colloidal stabilization.

  17. Surface patterning of nanoparticles with polymer patches

    NASA Astrophysics Data System (ADS)

    Choueiri, Rachelle M.; Galati, Elizabeth; Thérien-Aubin, Héloïse; Klinkova, Anna; Larin, Egor M.; Querejeta-Fernández, Ana; Han, Lili; Xin, Huolin L.; Gang, Oleg; Zhulina, Ekaterina B.; Rubinstein, Michael; Kumacheva, Eugenia

    2016-10-01

    Patterning of colloidal particles with chemically or topographically distinct surface domains (patches) has attracted intense research interest. Surface-patterned particles act as colloidal analogues of atoms and molecules, serve as model systems in studies of phase transitions in liquid systems, behave as ‘colloidal surfactants’ and function as templates for the synthesis of hybrid particles. The generation of micrometre- and submicrometre-sized patchy colloids is now efficient, but surface patterning of inorganic colloidal nanoparticles with dimensions of the order of tens of nanometres is uncommon. Such nanoparticles exhibit size- and shape-dependent optical, electronic and magnetic properties, and their assemblies show new collective properties. At present, nanoparticle patterning is limited to the generation of two-patch nanoparticles, and nanoparticles with surface ripples or a ‘raspberry’ surface morphology. Here we demonstrate nanoparticle surface patterning, which utilizes thermodynamically driven segregation of polymer ligands from a uniform polymer brush into surface-pinned micelles following a change in solvent quality. Patch formation is reversible but can be permanently preserved using a photocrosslinking step. The methodology offers the ability to control the dimensions of patches, their spatial distribution and the number of patches per nanoparticle, in agreement with a theoretical model. The versatility of the strategy is demonstrated by patterning nanoparticles with different dimensions, shapes and compositions, tethered with various types of polymers and subjected to different external stimuli. These patchy nanocolloids have potential applications in fundamental research, the self-assembly of nanomaterials, diagnostics, sensing and colloidal stabilization.

  18. Coral distribution patterns in Miocene Reefs of Anguilla, Leeward Islands, West Indies

    SciTech Connect

    Foster, A.B.; Johnson, K.G.

    1988-01-01

    Anguilla, a 27 by 5 km island at 18/sup 0/13'N, 63/sup 0/05'W, parallels the northwest edge of the Anguilla bank (St. Martin plateau) in the outer lesser Angilles volcanic arc, which was active from the Eocene to Oligocene. Except for scattered exposures of tuff or basalt, the island is composed predominantly of reefal limestones and marls of the 70-m thick, middle Miocene Anguilla Formation, deposited on a shallow inner shelf platform extending from volcanoes near St. Martin. The reef framework consists of branched and platy corals interspersed with calcareous sand lenses. Although the limestones have been uplifted and subjected to minor faulting, little evidence supports extensive transport across a slope. Coral distribution patterns have been quantified across the reefal units by point-counting species occurrences at 0.16-m intervals within 1-m/sup 2/ quadrants placed haphazardly across vertical exposures. Eight coral species (of possibly 18 total) were recorded. Cluster analysis delineated four facies: (1) a low-diversity facies dominated by branched Porites, (2) an intermediate diversity facies dominated by branched Porites, (3) a high-diversity facies dominated by massive Montastraea, Siderastrea, and Porites, and (4) an intermediate diversity facies dominated by platy Porites. These facies consists of lenses, no more than 100 m long and 2 m high, arranged in no apparent regular sequence. Thus, they do not represent zones across a depth gradient. Comparisons with living Caribbean reefs suggests that the Anguilla Miocene reefs were similar to small, modern, backreef fringing and patch reefs near the San Blas Islands of Panama, reefs whose variable composition and patchy distribution depend largely on sedimentation and current patterns.

  19. Coral reef evolution on rapidly subsiding margins

    USGS Publications Warehouse

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

    2009-01-01

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

  20. Mapping Oyster Reef Habitats in Mobile Bay

    NASA Technical Reports Server (NTRS)

    Bolte, Danielle

    2011-01-01

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

  1. Coral reef ecosystem decline: changing dynamics of coral reef carbonate production and implications for reef growth potential

    NASA Astrophysics Data System (ADS)

    Perry, Chris

    2016-04-01

    Global-scale deteriorations in coral reef health have caused major shifts in species composition and are likely to be exacerbated by climate change. It has been suggested that one effect of these ecological changes will be to lower reef carbonate production rates, which will impair reef growth potential and, ultimately, may lead to states of net reef erosion. However, quantitative data to support such assertions are limited, and linkages between the ecological state of coral reefs and their past and present geomorphic performance (in other words their growth potential) are poorly resolved. Using recently collected data from sites in the Caribbean and Indian Ocean, and which have undergone very different post-disturbance ecological trajectories over the last ~20-30 years, the differential impacts of disturbance on contemporary carbonate production regimes and on reef growth potential can be explored. In the Caribbean, a region which has been severely impacted ecological over the last 30+ years, our datasets show that average carbonate production rates on reefs are now less than 50% of pre-disturbance rates, and that calculated accretion rates (mm yr-1) are an about order of magnitude lower within shallow water habitats compared to Holocene averages. Collectively, these data suggest that recent ecological declines are now propagating through the system to impact on the geomorphic performance of Caribbean reefs and will impair their future growth potential. In contrast, the carbonate budgets of most reefs across the Chagos archipelago (central Indian Ocean), which is geographically remote and largely isolated from direct human disturbances, have recovered rapidly from major past disturbances (specifically the 1998 coral bleaching event). The carbonate budgets on these remote reefs now average +3.7 G (G = kg CaCO3 m-2 yr-1). Most significantly the production rates on Acropora-dominated reefs, which were most severely impacted by the 1998 bleaching event, average +8.4 G

  2. First documentation of tidal-channel sponge biostromes (upper Pleistocene, southeastern Florida)

    NASA Astrophysics Data System (ADS)

    Cunningham, Kevin J.; Rigby, J. Keith; Wacker, Michael A.; Curran, H. Allen

    2007-05-01

    Sponges are not a common principal component of Cenozoic reefs and are more typically dominant in deep-water and/or cold-water localities. Here we report the discovery of extensive upper Pleistocene shallow-marine, tropical sponge biostromes from the Miami Limestone of southeastern Florida built by a new ceractinomorph demosponge. These upright, barrel- to vase-shaped sponges occur in monospecific aggregations constructed within the tidal channels of an oolitic tidal-bar belt similar to modern examples on the Great Bahama Bank. The biostromes appear to have a ribbon-like geometry, with densely spaced sponges populating a paleochannel along a 3.5 km extent in the most lengthy biostrome. These are very large (as high as 2 m and 1.8 m in diameter), particularly well-preserved calcified sponges with walls as hard as concrete. Quartz grains are the most common particles agglutinated in the structure of the sponge walls. Where exposed, sediment fill between the sponges is commonly a highly burrowed or cross-bedded ooid-bearing grainstone and, locally, quartz sand. It is postulated that the dense, localized distribution of these particular sponges was due to a slight edge over competitors for food or energy supply and space in a stressed environment of tidal-influenced salinity and nutrient changes, strong currents, and frequently shifting submarine sand dunes. To our knowledge, this represents the first documentation of sponge biostromes composed of very large upright sponges within high-energy tidal channels between ooid shoals. The remarkably well-preserved accumulations provide an alternative example of sponge reefs for comparative paleoenvironmental studies.

  3. First documentation of tidal-channel sponge biostromes (upper Pleistocene, southeastern Florida)

    USGS Publications Warehouse

    Cunningham, K.J.; Rigby, J.K.; Wacker, M.A.; Curran, H.A.

    2007-01-01

    Sponges are not a common principal component of Cenozoic reefs and are more typically dominant in deep-water and/or cold-water localities. Here we report the discovery of extensive upper Pleistocene shallow-marine, tropical sponge biostromes from the Mami Limestone of southeastern Florida built by a new ceractinomorph demosponge. These upright, barrel- to vase-shaped sponges occur in monospecific aggregations constructed within the tidal channels of an oolitic tidal-bar belt similar to modern examples on the Great Bahama Bank. The biostromes appear to have a ribbon-like geometry, with densely spaced sponges populating a paleochannel along a 3.5 km extent in the most lengthy biostrome. These are very large (as high as 2 m and 1.8 m in diameter), particularly well-preserved calcified sponges with walls as hard as concrete. Quartz grains are the most common particles agglutinated in the structure of the sponge walls. Where exposed, sediment fill between the sponges is commonly a highly burrowed or cross-bedded ooid-bearing grainstone and, locally, quartz sand. It is postulated that the dense, localized distribution of these particular sponges was due to a slight edge over competitors for food or energy supply and space in a stressed environment of tidal-influenced salinity and nutrient changes, strong currents, and frequently shifting submarine sand dunes. To our knowledge, this represents the first documentation of sponge biostromes composed of very large upright sponges within high-energy tidal channels between ooid shoals. The remarkably well-preserved accumulations provide an alternative example of sponge reefs for comparative paleoenvironmental studies. ?? 2007 The Geological Society of America.

  4. Pleistocene lake level changes in Western Mongolia

    NASA Astrophysics Data System (ADS)

    Borodavko, P. S.

    2009-04-01

    Global cooling in the Early Pleistocene caused extensive continental glaciation in the northern hemisphere including the arid areas of Central Asia. The reduction of temperatures (particularly summer temperatures) reduced evaporation and strengthened the importance of precipitation. The simultaneity of "lakes periods" (pluvials) and stages of glaciation is established experience confirmed by investigations in the west of North America and Russia. In the Mongolian Great Lakes Depression new evidence for similar conditions is found. The Great Lakes Depression is one of the largest in Central Asia, and is divided into 2 main Lakes basins: Hyargas Lake Basin and Uvs Lake Basin. The basin is 600-650 km in length with a width of 200-250 km in the north and 60-100 km in the south. Total catchment area is about 186600 km2. The elevation of the basin floor is from 1700 m a.s.l. to 760 m a.s.l., decreasing to the north and south-east. The depression extends south-north and is bounded by mountains: Tannu-Ola to the north, Hangai to the east; Gobi Altai to the south and Mongolian Altay to the west. The maximum elevation of the mountains is 4000 m a.s.l. There are some mountains with an elevation between 2000 and 3000 m a.s.l in the lake catchment. These mountains are not glaciated today. The geological record [1] suggests the Great Lakes Depression already existed in the Mesozoic, but assumed its modern form only during the Pliocene-Quaternary when tectonic movements caused the uplift of the surrounding mountains. A phase of tectonic stability occurred during the Late Quaternary. The depression is filled by Quaternary fluvial, aeolian and lacustrine deposits (e.g. sand, pebbles). The Neogene deposits are represented by coloured clay, marl, sand and sandstone [1]. Hyargas Lake is the end base level of erosion of the lake group consisting of the Hara-Us Nur, Dorgon, Hara Nur and Airag lakes. Hyargas is one of the largest lakes in Mongolia, with a water surface of 1,407 km2. The

  5. Deformation of Polar Cap Patches During Substorms

    NASA Astrophysics Data System (ADS)

    Zou, S.; Ridley, A. J.; Nicolls, M. J.; Coster, A. J.; Thomas, E. G.; Ruohoniemi, J. M.; Hampton, D.

    2015-12-01

    Polar cap patches refer to the islands of high F-region plasma density within the polar cap. Their formation on the dayside and deformation on the nightside are not well understood. The F-layer ionosphere density is strongly influenced by electric field, thermospheric wind as well as soft particle precipitation. This study combines observations from multiple instruments, including Poker Flat incoherent scatter radar, GPS TEC and optical instruments, as well as the Global Ionosphere and Thermosphere Model (GITM), to investigate the effects of highly structured electric fields and winds on the deformation of polar cap patches during substorms. We will also discuss variations of the auroral emissions associated with the patch evolution.

  6. Tunable nano dispersed LC based patch antenna

    NASA Astrophysics Data System (ADS)

    Karim, Afaque; Yadav, Harsh; Ahmad, Shakeb

    2015-06-01

    This paper presents Patch antenna based on pure and Nano dispersed liquid crystals (LCs) for earth and space applications. Patch antenna are one of the most attractive antennas designed for RF frequency. To fulfill the demand of modern antenna i.e. tunability, a design of LC based patch antenna with optimum frequency of 15 GHz is investigated. In this design, NLC and ZnO doped NLC were used as a dielectric substrate. Its dielectric permittivity was controlled by biasing voltage. The dielectric properties of the 4-Cyano-4' -pentylbiphenyl (5CB) nematic liquid crystal (NLC), and NLC doped with Zinc oxide (ZnO) Nanoparticles was studied at room temperature. The concentration of doping material was 0.5% by w.t. in ZnO. Results shows that dielectric parameters are strong function of frequency and applied bias voltage. Moreover, Using doped NLC as dielectric substrate one gets more tunability or shift in resonant frequency in the proposed geometry.

  7. Cell repair: Revisiting the patch hypothesis

    PubMed Central

    Davenport, Nicholas R.

    2016-01-01

    ABSTRACT Plasma membrane damage elicits a complex and dynamic cellular response. A vital component of this response, membrane resealing, is thought to arise from fusion of intracellular membranous compartments to form a temporary, impermeant patch at the site of damage; however, this hypothesis has been difficult to confirm visually. By utilizing advanced microscopy technologies with high spatiotemporal resolution in wounded Xenopus laevis oocytes, we provide the first direct visualization of the membrane fusion events predicted by the patch hypothesis; we show the barrier formed by patching is capable of abating exchange of material across the plasma membrane within seconds. Profound changes also occur to the plasma membrane surrounding wounds; lipid remodeling is accompanied by membrane fusion events, both conventional (e.g., exocytosis) and novel (e.g., “explodosis”). Further, we reveal additional complexity in wound-induced subcellular patterning, supporting existing evidence that extensive interactions between lipid, protein, and ionic signaling pathways shape the cellular wound response. PMID:28042380

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

    PubMed

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

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Phipps, A.

    2012-04-01

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

  11. Boolean Operations with Prism Algebraic Patches

    PubMed Central

    Bajaj, Chandrajit; Paoluzzi, Alberto; Portuesi, Simone; Lei, Na; Zhao, Wenqi

    2009-01-01

    In this paper we discuss a symbolic-numeric algorithm for Boolean operations, closed in the algebra of curved polyhedra whose boundary is triangulated with algebraic patches (A-patches). This approach uses a linear polyhedron as a first approximation of both the arguments and the result. On each triangle of a boundary representation of such linear approximation, a piecewise cubic algebraic interpolant is built, using a C1-continuous prism algebraic patch (prism A-patch) that interpolates the three triangle vertices, with given normal vectors. The boundary representation only stores the vertices of the initial triangulation and their external vertex normals. In order to represent also flat and/or sharp local features, the corresponding normal-per-face and/or normal-per-edge may be also given, respectively. The topology is described by storing, for each curved triangle, the two triples of pointers to incident vertices and to adjacent triangles. For each triangle, a scaffolding prism is built, produced by its extreme vertices and normals, which provides a containment volume for the curved interpolating A-patch. When looking for the result of a regularized Boolean operation, the 0-set of a tri-variate polynomial within each such prism is generated, and intersected with the analogous 0-sets of the other curved polyhedron, when two prisms have non-empty intersection. The intersection curves of the boundaries are traced and used to decompose each boundary into the 3 standard classes of subpatches, denoted in, out and on. While tracing the intersection curves, the locally refined triangulation of intersecting patches is produced, and added to the boundary representation. PMID:21516262

  12. Late Pleistocene-Holocene acceleration of uplift rate in southwest Erromango Island, Southern Vanuatu, South Pacific: relation to the growth of the Vanuatuan Mid Sedimentary Basin

    SciTech Connect

    Neef, G.; Hendy, C.

    1988-07-01

    Late Quaternary and Holocene raised coral reefs are well developed in southwestern Erromango Island, which lies in the frontal arc area of the Vanuatuan Island Arc. Eight uranium series ages and one /sup 14/C age from samples from coral reefs at three localities range in age from 4800 B.P. to about 320,000 B.P. Six of the samples dated are from the Matiwo Point area. Here the youngest reef has given a /sup 230/Th//sup 234/U age of 4800 B.P. and a slightly older reef, 4.3 m higher in elevation, has a /sup 14/C age of 5270 B.P. Inland of a cliff the youngest three of four northeastward-tilted raised reefs have given /sup 230/Th//sup 234/U ages ranging from 104,000 B.P. to about 320,000 B.P. These data indicate accelerating uplift rates for southwest Erromango: during the periods 320,000-133,000 B.P., 133,000-6000 B.P., and 6000 - 0 B.P. average uplift rates were 0.33 mm/yr, 0.65 mm/yr, and about 1 mm/yr respectively. These data are interpreted to indicate the growth of the Mid Sedimentary Basin, which lies within the frontal and volcanic arc part of the island arc complex. This increase in uplift/eastward-tilting could represent a Quaternary-Late Pleistocene increase in the subduction rate of the Australian Plate beneath Erromango.

  13. Epidural blood patch and acute varicella.

    PubMed

    Martin, David P; Bergman, Bradley D; Berger, Ines H

    2004-12-01

    We present the case of a 38-yr-old woman who required an epidural blood patch in the context of acute varicella (chickenpox). The unique risks in this case include the possible triggering of central nervous system complications after the introduction of viremic blood into the epidural or intrathecal space. However, the risk was believed to be acceptable because the patient was receiving antiviral coverage. She enjoyed complete relief of her headache but experienced transient back and leg pain. Leptomeningeal irritation caused by acute varicella infection may put patients at increased risk for pain after epidural blood patch.

  14. Patch Clamping Protoplasts from Vascular Plants 1

    PubMed Central

    Elzenga, J. Theo M.; Keller, Christopher P.; Van Volkenburgh, Elizabeth

    1991-01-01

    A method is described for the isolation of protoplasts (Pisum sativum, Phaseolus vulgaris, Avena sativa, Arabidopsis thaliana) in preparation for ion flux studies using patch clamp electrophysiology. Protoplasts that have been exposed to hydrolytic, cell wall degrading, enzymes for as little as 5 minutes form gigaseals (seal resistance higher than 10 giga Ohm) with the patch pipette with success rates greater than 40%. Sealing of these protoplasts is fast, averaging less than 2 minutes. This method yields high rates of gigaseal formation in a variety of tissues from both monocots and dicots and will enhance data collection in ion flux studies of plasma membranes of vascular plants. PMID:16668586

  15. Lightweight Material Patches Allow for Quick Repairs

    NASA Technical Reports Server (NTRS)

    2010-01-01

    Cornerstone Research Group Inc., of Dayton, Ohio, has been the recipient of 16 Small Business Innovation Research (SBIR) contracts with NASA with a variety of different focuses, including projects like creating inflatable structures for radio frequency antennas and, most recently, healable polymer matrix composites for future space vehicles. One of its earlier SBIR contracts, with Kennedy Space Center, led to the development of a new type of structural patch for a variety of consumer uses: Rubbn Repair, for automotive uses; and Rec Repair for the outdoors and adventure market. Both are flexible, heat-activated structural patches.

  16. Artificial Reefs--A Coastal Classroom Project.

    ERIC Educational Resources Information Center

    Dindo, John J.

    1986-01-01

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

  17. Along-Track Reef Imaging System (ATRIS)

    USGS Publications Warehouse

    Brock, John; Zawada, Dave

    2006-01-01

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

  18. Subtropical Biotic Fringing Reefs as Ecological Laboratories.

    ERIC Educational Resources Information Center

    Hunt, Jeffrey W.

    1980-01-01

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

  19. Silurian pinnacle reefs of the Canadian Arctic

    SciTech Connect

    De Freitas, T.A.; Dixon, O.A. ); Mayr, U. )

    1993-04-01

    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.

  20. Reefs and Learning: Education Evaluation Techniques

    ERIC Educational Resources Information Center

    Stepath, Carl M.

    2006-01-01

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

  1. Disease of coral and coral reef fishes

    USGS Publications Warehouse

    Panek, Frank

    2008-01-01

    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.

  2. Bathymetric distribution of foraminifera in Jamaican reef environments

    SciTech Connect

    Martin, R.E.; Liddell, W.D.

    1985-02-01

    Recent foraminifera inhabiting Jamaican north-coast fringing reefs display variations in distributional patterns that are related to bathymetry and reef morphology. Sediment samples containing foraminifera were collected along a profile that traversed the back reef (depth 1-2 m), fore-reef terrace (3-15 m), fore-reef escarpment (15-27 m), fore-reef slope (30-55 m), and upper deep fore reef (70 m). Approximately 150 species distributed among 80 genera were identified from the samples. Preliminary analyses indicate that diversity values (S, H') are lowest on the fore-reef terrace (79, 3.0, respectively), increase similarly in back-reef and fore-reef escarpment and slope settings (93, 3.4), and are highest on the deep fore reef (109, 3.7). Larger groupings (suborders) exhibit distinct bathymetric trends with miliolids occurring more commonly in back-reef (comprising 51% of the fauna) than in fore-reef (28%) zones, whereas agglutinated and planktonic species occur more commonly in deeper reef (> 15 m, 9% and 4%, respectively) than in shallower reef zones (< 15 m, 3%, and 0.5%, respectively). Among the more common species Amphistegina gibbosa (Rotolina) is much more abundant in fore-reef (3%) environments, and Sorites marginalis (Miliolina) occurs almost exclusively in the back reef, where it comprises 5.5% of the fauna. Q-mode cluster analysis, involving all species collected, enabled the delineation of back-reef, shallow fore-reef, and deeper fore-reef biofacies, also indicating the potential utility of foraminiferal distributions in detailed paleoenvironment interpretations of ancient reef settings.

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

    PubMed

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

    2013-01-01

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

  4. Pleistocene surface water temperatures in the Benguela upwelling area

    NASA Astrophysics Data System (ADS)

    Os'kina, N. S.; Dmitrenko, O. B.

    2011-08-01

    Analysis of carbonate microfossils (planktonic foraminifers and nannoplankton) in the DSDP Hole 362 Quaternary section made it possible to specify its zonal subdivision (almost all zones of Gartner's high-resolution nannofossil scale are recognized), establish depositional environments, and restore past surface water temperatures. The latter appeared to be several degrees lower than their present-day values, which is evident from the anomalously high share of the subpolar species Neogloboquadrina pachyderma sin. that constitutes 97% of the fossil assemblage in Lower Pleistocene sediments. It is shown that the Benguela upwelling existed throughout the entire Pleistocene, being less intense in the Late Pleistocene and Holocene.

  5. Patches for Carotid Artery Endarterectomy: Current Materials and Prospects

    PubMed Central

    Muto, Akihito; Nishibe, Toshiya; Dardik, Herbert; Dardik, Alan

    2009-01-01

    Patch angioplasty is commonly performed after carotid endarterectomy. Randomized prospective trials and meta-analyses have documented improved rates of perioperative and long-term stroke prevention as well as reduced rates of restenosis for patches compared to primary closure of the arteriotomy. Although use of vein patches is considered to be the “gold standard” for patch closure, newer generations of synthetic and biological materials rival outcomes associated with vein patches. Future bioengineered patches are likely to optimize patch performance, both by achieving minimal stroke risk and long-term rates of restenosis, as well as by minimizing the risk of unusual complications of prosthetic patches such as infection and pseudoaneurysm formation; in addition, lessons from bioengineered patches will likely enable construction of bioengineered and tissue-engineered bypass grafts. PMID:19563972

  6. Edgecliff reefs - Devonian temperate water carbonate deposition

    SciTech Connect

    Wolosz, T.H. )

    1991-03-01

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

  7. Critical patch sizes for food-web modules.

    PubMed

    Martinson, Holly M; Fagan, William F; Denno, Robert F

    2012-08-01

    Because patch size and connectivity may strongly impact the assemblage of species that occur on a patch, the types of food-web interactions that occur among those species may also depend on spatial structure. Here, we identify whether food-web interactions among salt-marsh-inhabiting arthropods vary with patch size and connectivity, and how such changes in trophic structure might feed back to influence the spatial distribution of prey. In a multiyear survey, patch-restricted predators exhibited steeper occupancy-patch-size relationships than herbivores, and species' critical patch sizes were correlated with overall rarity. As a result, the presence of food-web modules depended strongly on patch size: large and well-connected patches supported complex food-web modules, but only the simplest modules involving the most abundant species were found on small patches. Habitat-generalist spiders dominated on small patches, and predation pressure from such species may contribute to the observed lower densities of mesopredators on small patches. Overall, patch size and connectivity influenced the types of modules present on a patch through differential loss of rare, patch-restricted predators, but predation by generalist predators may be a key mechanism influencing the spatial structure of certain prey species.

  8. Dispersal, patch leaving, and distribution of Homalodisca vitripennis (Hemiptera: Cicadellidae).

    PubMed

    Northfield, Tobin D; Mizell, Russell F; Paini, Dean R; Andersen, Peter C; Brodbeck, Brent V; Riddle, T Charles; Hunter, Wayne B

    2009-02-01

    Homalodisca vitripennis (Germar) and related species have caused millions of dollars in damage to southern California vineyards in recent years through the vectoring of Pierce's disease. However, the effects of surrounding vegetation on the dispersal and distribution of H. vitripennis are poorly understood. Therefore, the relationship between dispersal rates and patch quality was tested, as well as the basic predictions of the marginal value theorem. Additional experiments were conducted to compare the H. vitripennis distribution in an isolated crape myrtle (Lagerstroemia indica) patch and a L. indica patch bordering two alternative host patches. In mark-release-recapture tests, H. vitripennis dispersed farther from the release point in a patch of low-quality host plants (Prunus persica) than in patches of high-quality host plants (L. indica). In addition, H. vitripennis remained in L. indica patches longer than in P. persica patches and adjusted patch residence times in P. persica in correlation with known changes in plant physiology. These data suggest that H. vitripennis follows the basic predictions of marginal value theorem. In distribution tests, H. vitripennis were more abundant in the patch center than patch edges in the isolated L. indica patch, but in a patch bordering cottonwood (Populus sp.) and peach (P. persica), H. vitripennis numbers were generally higher along the edges of the patch. These data suggest that alternate hosts bordering cropping systems may be important to the spatial dynamics of H. vitripennis. Implications of these spatial observations on the biology of H. vitripennis and potential control methods are discussed.

  9. A novel reef coral symbiosis

    NASA Astrophysics Data System (ADS)

    Pantos, O.; Bythell, J. C.

    2010-09-01

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

  10. Benthic foraminifera baseline assemblages from a coastal nearshore reef complex on the central Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Johnson, Jamie; Perry, Chris; Smithers, Scott; Morgan, Kyle

    2016-04-01

    Declining water quality due to river catchment modification since European settlement (c. 1850 A.D.) represents a major threat to the health of coral reefs on Australia's Great Barrier Reef (GBR), particularly for those located in the coastal waters of the GBR's inner-shelf. These nearshore reefs are widely perceived to be most susceptible to declining water quality owing to their close proximity to river point sources. Despite this, nearshore reefs have been relatively poorly studied with the impacts and magnitudes of environmental degradation still remaining unclear. This is largely due to ongoing debates concerning the significance of increased sediment yields against naturally high background sedimentary regimes. Benthic foraminifera are increasingly used as tools for monitoring environmental and ecological change on coral reefs. On the GBR, the majority of studies have focussed on the spatial distributions of contemporary benthic foraminiferal assemblages. While baseline assemblages from other environments (e.g. inshore reefs and mangroves) have been described, very few records exist for nearshore reefs. Here, we present preliminary results from the first palaeoecological study of foraminiferal assemblages of nearshore reefs on the central GBR. Cores were recovered from the nearshore reef complex at Paluma Shoals using percussion techniques. Recovery was 100%, capturing the entire Holocene reef sequence of the selected reef structures. Radiocarbon dating and subsequent age-depth modelling techniques were used to identify reef sequences pre-dating European settlement. Benthic foraminifera assemblages were reconstructed from the identified sequences to establish pre-European ecological baselines with the aim of providing a record of foraminiferal distribution during vertical reef accretion and against which contemporary ecological change may be assessed.

  11. Multimode Broad-Band Patch Antennas

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R.

    2003-01-01

    Microstrip patch antennas of a proposed type would be tunable over broad wavelength ranges. These antennas would be attractive for use in a variety of microwave communication systems in which there are requirements for transmission and/or reception at multiple, widely separated frequencies. Prior efforts to construct tunable microstrip patch antennas have involved integration of microstrip circuitry with, variously, ferrite films with magneticfield tuning, solid-state electronic tuning devices, or piezoelectric tuning actuators. Those efforts have been somewhat successful, but have yielded tuning ranges of 20 percent and smaller much smaller than needed in typical practical cases. Like prior microstrip patch antennas (both tunable and non-tunable), the proposed antennas would have instantaneous bandwidths of about 1 percent of their nominal or resonance frequencies. However, these would be tunable over much broader frequency ranges as much as several octaves, depending on specific designs. They could be fabricated relatively simply and inexpensively by use of conventional photolithography, and without need for integration with solid-state electronic or piezoelectric control devices. An antenna as proposed (see figure) would include a microstrip patch radiating element on a thin ferroelectric film on a semiconductor substrate with a ground-plane conductor on the underside of the substrate. The ferroelectric film could be, for example, SrTiO3 with a thickness of the order of 1 or 2 micrometers.

  12. Juno Microwave Radiometer Patch Array Antennas

    NASA Technical Reports Server (NTRS)

    Chamberlain, N.; Chen, J.; Focardi, P.; Hodges, R.; Hughes, R.; Jakoboski, J.; Venkatesan, J.; Zawadzki, M.

    2009-01-01

    Juno is a mission in the NASA New Frontiers Program with the goal of significantly improving our understanding of the formation and structure of Jupiter. This paper discusses the modeling and measurement of the two patch array antennas. An overview of the antenna architecture, design and development at JPL is provided, along with estimates of performance and the results of measurements.

  13. Soil, Seeds, and the Pumpkin Patch!

    ERIC Educational Resources Information Center

    Phillips, Marianne; Vowell, Julie

    2013-01-01

    "Soil, Seeds, and the Pumpkin Patch!" is an integrated unit designed to provide elementary school teachers with ideas for using hands-on activities, fostering inquiry and valuable discussion, and using technology as a learning tool. This unit integrates science with language arts, mathematics, literature, and technology. During this unit, students…

  14. Analgesic Microneedle Patch for Neuropathic Pain Therapy.

    PubMed

    Xie, Xi; Pascual, Conrado; Lieu, Christopher; Oh, Seajin; Wang, Ji; Zou, Bende; Xie, Julian; Li, Zhaohui; Xie, James; Yeomans, David C; Wu, Mei X; Xie, Xinmin Simon

    2017-01-24

    Neuropathic pain caused by nerve injury is debilitating and difficult to treat. Current systemic pharmacological therapeutics for neuropathic pain produce limited pain relief and have undesirable side effects, while current local anesthetics tend to nonspecifically block both sensory and motor functions. Calcitonin gene related peptide (CGRP), a neuropeptide released from sensory nerve endings, appears to play a significant role in chronic neuropathic pain. In this study, an analgesic microneedle (AMN) patch was developed using dissolvable microneedles to transdermally deliver selective CGRP antagonist peptide in a painless manner for the treatment of localized neuropathic pain. Local analgesic effects were evaluated in rats by testing behavioral pain sensitivity in response to thermal and mechanical stimuli using neuropathic pain models such as spared-nerve injury and diabetic neuropathy pain, as well as neurogenic inflammatory pain model induced by ultraviolet B (UVB) radiation. Unlike several conventional therapies, the AMN patches produced effective analgesia on neuropathic pain without disturbing the normal nociception and motor function of the rat, resulting from the high specificity of the delivered peptide against CGRP receptors. The AMN patches did not cause skin irritation or systemic side effects. These results demonstrate that dissolvable microneedle patches delivering CGRP antagonist peptide provide an effective, safe, and simple approach to mitigate neuropathic pain with significant advantages over current treatments.

  15. A Practical Guide to Patch Testing.

    PubMed

    Fonacier, Luz

    2015-01-01

    Contact dermatitis is a common disease seen by allergists, dermatologists, and primary care physicians. The gold standard for diagnosing allergic contact dermatitis (ACD) is patch testing and is indicated in any patient with a chronic, pruritic, eczematous, or lichenified dermatitis if underlying or secondary ACD is suspected. Patients with acute generalized dermatitis who have extensive eczema on the back, are on immunosuppressant medications, and have applied topical corticosteroids, topical calcineurin inhibitors, or ultraviolet radiation to the patch test (PT) site may have suppressed PT reactions. The procedure of patch testing is not a difficult one to perform, but the interpretation of the PT needs some critical components, including having an appropriate level of suspicion for the diagnosis of ACD, testing the relevant allergens in their proper vehicle and concentration, and the necessary experience to properly interpret the results. Careful history and physical examination must be correlated with the result of the PT to establish clinical relevance. Once the PT is completed, allergens are identified, and relevance has been established, educating the patient about the avoidance of exposure is critical. The Joint Task Force of the American Academy of Allergy, Asthma and Immunology and American College of Allergy, Asthma and Immunology has developed updated practice parameters for contact dermatitis and patch testing, and their recommendations will be discussed (Fonacier LF, Bernstein DI, Pacheco K, Holness DL. Contact dermatitis: a practice parameter update 2015. J Allergy Clin Immunol Pract 2015; 3(3S):S1-S40.).

  16. 76 FR 59377 - Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-26

    ..., Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and Invertebrates Fishery Management... Fishery Management Plans (FMPs) for Reef Fish Resources, Spiny Lobster, Queen Conch, and Coral and Reef... and coral and reef associated plants and invertebrates species. The 2011 Caribbean ACL Amendment...

  17. Detecting coral bleaching using high-resolution satellite data analysis and 2-dimensional thermal model simulation in the Ishigaki fringing reef, Japan

    NASA Astrophysics Data System (ADS)

    Dadhich, A. P.; Nadaoka, K.; Yamamoto, T.; Kayanne, H.

    2012-06-01

    In 2007, high-temperature-induced mass coral mortality was observed in a well-developed fringing reef area on the southeastern coast of Ishigaki Island, Japan. To analyze the response of the corals to thermal stress, the coral cover was examined using Quickbird data, taken across the reef flat just before and after the bleaching event and performing a reef scale horizontal 2-dimensional thermal model simulation. The Quickbird data consisted of multispectral (MSS) imagery, which had a spatial resolution of 2.4 m, and panchromatic (PAN)-fused multispectral imagery, which had a 0.6-m spatial resolution. The observed changes in coral cover implied that the delineation of partially bleached coral was more precise with PAN + MSS. The classification accuracy achieved using PAN + MSS (93%) was superior to that obtained using MSS (88%). The in situ water temperature observations and 2-dimensional thermal model simulation results indicated that the water temperature fluctuated greatly in the inner reef area in late July 2007. Different thermal stress indices, including daily average temperature, daily maximum excess temperature, and daily accumulated temperature, were examined to define a suitable index that represented the severity of the thermal stress on coral cover. The results suggested that the daily accumulated temperature that occurred during the maximum sea surface temperature period of the bleaching season provided the best predictor of bleaching. The changes in water temperature, bathymetry, and coral patch size affected the severity of bleaching; therefore, the spatial dependence of these variables was examined using Moran's I and Lagrange multiplier tests. An investigation of the effect of coral patch sizes on coral bleaching indicated that large coral patches were less affected than the small patches, which were more likely to suffer bleaching and coral mortality.

  18. Whole-GUV patch-clamping.

    PubMed

    Garten, Matthias; Mosgaard, Lars D; Bornschlögl, Thomas; Dieudonné, Stéphane; Bassereau, Patricia; Toombes, Gilman E S

    2017-01-10

    Studying how the membrane modulates ion channel and transporter activity is challenging because cells actively regulate membrane properties, whereas existing in vitro systems have limitations, such as residual solvent and unphysiologically high membrane tension. Cell-sized giant unilamellar vesicles (GUVs) would be ideal for in vitro electrophysiology, but efforts to measure the membrane current of intact GUVs have been unsuccessful. In this work, two challenges for obtaining the "whole-GUV" patch-clamp configuration were identified and resolved. First, unless the patch pipette and GUV pressures are precisely matched in the GUV-attached configuration, breaking the patch membrane also ruptures the GUV. Second, GUVs shrink irreversibly because the membrane/glass adhesion creating the high-resistance seal (>1 GΩ) continuously pulls membrane into the pipette. In contrast, for cell-derived giant plasma membrane vesicles (GPMVs), breaking the patch membrane allows the GPMV contents to passivate the pipette surface, thereby dynamically blocking membrane spreading in the whole-GMPV mode. To mimic this dynamic passivation mechanism, beta-casein was encapsulated into GUVs, yielding a stable, high-resistance, whole-GUV configuration for a range of membrane compositions. Specific membrane capacitance measurements confirmed that the membranes were truly solvent-free and that membrane tension could be controlled over a physiological range. Finally, the potential for ion transport studies was tested using the model ion channel, gramicidin, and voltage-clamp fluorometry measurements were performed with a voltage-dependent fluorophore/quencher pair. Whole-GUV patch-clamping allows ion transport and other voltage-dependent processes to be studied while controlling membrane composition, tension, and shape.

  19. Surface patterning of nanoparticles with polymer patches

    DOE PAGES

    Choueiri, Rachelle M.; Galati, Elizabeth; Thérien-Aubin, Héloïse; ...

    2016-08-24

    Patterning of colloidal particles with chemically or topographically distinct surface domains (patches) has attracted intense research interest. Surface-patterned particles act as colloidal analogues of atoms and molecules serve as model systems in studies of phase transitions in liquid systems, behave as ‘colloidal surfactants’ and function as templates for the synthesis of hybrid particles. The generation of micrometre- and submicrometre-sized patchy colloids is now efficient but surface patterning of inorganic colloidal nanoparticles with dimensions of the order of tens of nanometres is uncommon. Such nanoparticles exhibit size- and shape-dependent optical, electronic and magnetic properties, and their assemblies show new collective properties.more » At present, nanoparticle patterning is limited to the generation of two-patch nanoparticles and nanoparticles with surface ripples or a ‘raspberry’ surface morphology. We demonstrate nanoparticle surface patterning, which utilizes thermodynamically driven segregation of polymer ligands from a uniform polymer brush into surface-pinned micelles following a change in solvent quality. Patch formation is reversible but can be permanently preserved using a photocrosslinking step. The methodology offers the ability to control the dimensions of patches, their spatial distribution and the number of patches per nanoparticle, in agreement with a theoretical model. The versatility of the strategy is demonstrated by patterning nanoparticles with different dimensions, shapes and compositions, tethered with various types of polymers and subjected to different external stimuli. Furthermore, these patchy nanocolloids have potential applications in fundamental research, the self-assembly of nanomaterials, diagnostics, sensing and colloidal stabilization.« less

  20. Surface patterning of nanoparticles with polymer patches

    PubMed Central

    Choueiri, Rachelle M.; Galati, Elizabeth; Thérien-Aubin, Héloïse; Klinkova, Anna; Larin, Egor M.; Querejeta-Fernández, Ana; Han, Lili; Xin, Huolin L.; Gang, Oleg; Zhulina, Ekaterina B.; Rubinstein, Michael; Kumacheva, Eugenia

    2016-01-01

    Patterning of colloidal particles with chemically or topographically distinct surface domains (patches) has attracted intense research interest1–3. Surface-patterned particles act as colloidal analogues of atoms and molecules4,5, serve as model systems in studies of phase transitions in liquid systems6, behave as ‘colloidal surfactants’7 and function as templates for the synthesis of hybrid particles8. The generation of micrometre- and submicrometre-sized patchy colloids is now efficient9–11, but surface patterning of inorganic colloidal nanoparticles with dimensions of the order of tens of nanometres is uncommon. Such nanoparticles exhibit size- and shape-dependent optical, electronic and magnetic properties, and their assemblies show new collective properties12. At present, nanoparticle patterning is limited to the generation of two-patch nanoparticles13–15, and nanoparticles with surface ripples16 or a ‘raspberry’ surface morphology17. Here we demonstrate nanoparticle surface patterning, which utilizes thermodynamically driven segregation of polymer ligands from a uniform polymer brush into surface-pinned micelles following a change in solvent quality. Patch formation is reversible but can be permanently preserved using a photocrosslinking step. The methodology offers the ability to control the dimensions of patches, their spatial distribution and the number of patches per nanoparticle, in agreement with a theoretical model. The versatility of the strategy is demonstrated by patterning nanoparticles with different dimensions, shapes and compositions, tethered with various types of polymers and subjected to different external stimuli. These patchy nanocolloids have potential applications in fundamental research, the self-assembly of nanomaterials, diagnostics, sensing and colloidal stabilization. PMID:27556943

  1. Wave transformation across coral reefs under changing sea levels

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  2. Optically stimulated luminescence age controls on late Pleistocene and Holocene coastal lithosomes, North Carolina, USA

    USGS Publications Warehouse

    Mallinson, D.; Burdette, K.; Mahan, S.; Brook, G.

    2008-01-01

    Luminescence ages from a variety of coastal features on the North Carolina Coastal Plain provide age control for shoreline formation and relative sea-level position during the late Pleistocene. A series of paleoshoreline ridges, dating to Marine Isotope Stage (MIS) 5a and MIS 3 have been defined. The Kitty Hawk beach ridges, on the modern Outer Banks, yield ages of 3 to 2??ka. Oxygen-isotope data are used to place these deposits in the context of global climate and sea-level change. The occurrence of MIS 5a and MIS 3 shorelines suggests that glacio-isostatic adjustment (GIA) of the study area is large (ca. 22 to 26??m), as suggested and modeled by other workers, and/or MIS 3 sea level was briefly higher than suggested by some coral reef studies. Correcting the shoreline elevations for GIA brings their elevation in line with other sea-level indicators. The age of the Kitty Hawk beach ridges places the Holocene shoreline well west of its present location at ca. 3 to 2??ka. The age of shoreline progradation is consistent with the ages of other beach ridge complexes in the southeast USA, suggesting some regionally contemporaneous forcing mechanism. ?? 2007 University of Washington.

  3. A century of ocean warming on Florida Keys coral reefs: historic in situ observations

    USGS Publications Warehouse

    Kuffner, Ilsa B.; Lidz, Barbara H.; Hudson, J. Harold; Anderson, Jeffery S.

    2015-01-01

    There is strong evidence that global climate change over the last several decades has caused shifts in species distributions, species extinctions, and alterations in the functioning of ecosystems. However, because of high variability on short (i.e., diurnal, seasonal, and annual) timescales as well as the recency of a comprehensive instrumental record, it is difficult to detect or provide evidence for long-term, site-specific trends in ocean temperature. Here we analyze five in situ datasets from Florida Keys coral reef habitats, including historic measurements taken by lighthouse keepers, to provide three independent lines of evidence supporting approximately 0.8 °C of warming in sea surface temperature (SST) over the last century. Results indicate that the warming observed in the records between 1878 and 2012 can be fully accounted for by the warming observed in recent decades (from 1975 to 2007), documented using in situ thermographs on a mid-shore patch reef. The magnitude of warming revealed here is similar to that found in other SST datasets from the region and to that observed in global mean surface temperature. The geologic context and significance of recent ocean warming to coral growth and population dynamics are discussed, as is the future prognosis for the Florida reef tract.

  4. Experimental evaluation of diversity-productivity relationships in a coral reef fish assemblage.

    PubMed

    Messmer, Vanessa; Blowes, Shane A; Jones, Geoffrey P; Munday, Philip L

    2014-09-01

    The global decline in biodiversity is causing increasing concern about the effects of biodiversity loss on ecosystem services such as productivity. Biodiversity has been hypothesised to be important in maintaining productivity of biological assemblages because niche complementarity and facilitation among the constituent species can result in more efficient use of resources. However, these conclusions are primarily based on studies with plant communities, and the relationship between diversity and productivity at higher trophic levels is largely unknown, especially in the marine environment. Here, we used a manipulative field experiment to test the effects of species richness and species identity on biomass accumulation in coral reef fish assemblages at Lizard Island. Small patch reefs were stocked with a total of 30 juveniles belonging to three planktivorous damselfish (genus Pomacentrus) according to three different levels of fish species richness (one, two and three species) and seven different combinations of fish species. Species richness had no effect on the relative growth in this assemblage after 18 days, but relative growth differed among individual fish species and the different combinations of species. Patterns of increase in biomass were best explained by species-specific differences and variable effects of intra- and interspecific competition on growth. These results suggest that niche complementarity and facilitation are not the most influential drivers of total productivity within this guild of planktivorous fishes. Total productivity may be resilient to declining reef fish biodiversity, but this will depend on which species are lost and on the life-history traits of remaining species.

  5. Context-dependent landscape of fear: algal density elicits risky herbivory in a coral reef.

    PubMed

    Gil, Michael A; Zill, Julie; Ponciano, José M

    2017-02-01

    Foraging theory posits that isolation from refuge habitat within a landscape increases perceived predation risk and, thus, suppresses the foraging behavior of prey species. However, these effects may depend fundamentally on resource availability, which could affect prey boldness and can change considerably through bottom-up processes. We conducted a field survey and experiment in a coral reef to test the effects of isolation from refuge habitat (i.e., reef structure) on herbivory by reef fishes and whether these effects depend on resource density. By fitting continuous-time, pure death Markov processes to our data, we found that at both the local and landscape scale distance from refuge habitat reduced herbivory in attractive resource patches of palatable benthic algae. However, our field experiment revealed that higher initial resource densities weakened negative effects of distance from refuge habitat on herbivory. Furthermore, we observed higher bite rates and greater total lengths of herbivorous fishes with greater distance from refuge habitat-responses consistent with higher perceived predation risk. Our results suggest that while the loss or fragmentation of refuge habitat reduces consumer control of resources, greater resource densities can partially counteract this effect by altering landscapes of fear of consumer species. Our findings emphasize the importance of considering the spatial context of species interactions that structure communities.

  6. Late Pleistocene human remains from Wezmeh Cave, western Iran.

    PubMed

    Trinkaus, Erik; Biglari, Fereidoun; Mashkour, Marjan; Monchot, Hervé; Reyss, Jean-Louis; Rougier, Hélène; Heydari, Saman; Abdi, Kamyar

    2008-04-01

    Paleontological analysis of remains from Wezmeh Cave in western Iran have yielded a Holocene Chalcolithic archeological assemblage, a rich Late Pleistocene carnivore faunal assemblage, and an isolated unerupted human maxillary premolar (P(3) or possibly P(4)). Species representation and U-series dating of faunal teeth place the carnivore assemblage during oxygen isotope stages (OIS) 3 and 2, and noninvasive gamma spectrometry dating of the human premolar places it at least as old as early OIS 2. The human premolar crown morphology is not diagnostic of late archaic versus early modern human affinities, but its buccolingual diameter places it at the upper limits of Late Pleistocene human P(3) and P(4) dimensions and separate from a terminal Pleistocene regional sample. Wezmeh Cave therefore provides additional Paleolithic human remains from the Zagros Mountains and further documents Late Pleistocene human association with otherwise carnivore-dominated cave assemblages.

  7. Understanding patch departure rules for large carnivores: lion movements support a patch-disturbance hypothesis.

    PubMed

    Valeix, Marion; Chamaillé-Jammes, Simon; Loveridge, Andrew J; Davidson, Zeke; Hunt, Jane E; Madzikanda, Hillary; Macdonald, David W

    2011-08-01

    We test two hypotheses that could account for patch departure by large mammalian carnivores. One hypothesis is the unsuccessful-hunt hypothesis, where carnivores leave an area after an unsuccessful hunt but continue hunting in the same area after a successful hunt. The second hypothesis is the patch-disturbance hypothesis, where carnivores depart the area after a successful hunt because of behavioral responses of prey to predator presence. We used global positioning system collars to monitor the movements of African lions (Panthera leo) and identified their kill sites to distinguish between these two hypotheses. Lions moved to a different area (≥ 5 km away) after 87% of the kills, which supports the patch-disturbance hypothesis for patch-departure behavior of large mammalian carnivores.

  8. The effect of species and colony size on the bleaching response of reef-building corals in the Florida Keys during the 2005 mass bleaching event

    NASA Astrophysics Data System (ADS)

    Brandt, M. E.

    2009-12-01

    Understanding the variation in coral bleaching response is necessary for making accurate predictions of population changes and the future state of reefs in a climate of increasing thermal stress events. Individual coral colonies, belonging to inshore patch reef communities of the Florida Keys, were followed through the 2005 mass bleaching event. Overall, coral bleaching patterns followed an index of accumulated thermal stress more closely than in situ temperature measurements. Eight coral species ( Colpophyllia natans, Diploria strigosa, Montastraea cavernosa, M. faveolata, Porites astreoides, P. porites, Siderastrea siderea, and Stephanocoenia intersepta), representing >90% of the coral colonies studied, experienced intense levels of bleaching, but responses varied. Bleaching differed significantly among species: Colpophyllia natans and Diploria strigosa were most susceptible to thermal stress, while Stephanocoenia intersepta was the most tolerant. For colonies of C. natans, M. faveolata, and S. siderea, larger colonies experienced more extensive bleaching than smaller colonies. The inshore patch reef communities of the Florida Keys have historically been dominated by large colonies of Montastraea sp. and Colpophyllia natans. These results provide evidence that colony-level differences can affect bleaching susceptibility in this habitat and suggest that the impact of future thermal stress events may be biased toward larger colonies of dominant reef-building species. Predicted increases in the frequency of mass bleaching and subsequent mortality may therefore result in significant structural shifts of these ecologically important communities.

  9. Interannual changes in seafloor surficial geology at an artificial reef site on the inner continental shelf

    NASA Astrophysics Data System (ADS)

    Raineault, Nicole A.; Trembanis, Arthur C.; Miller, Douglas C.; Capone, Vince

    2013-04-01

    The influence of reef structures on seafloor surface sediments has implications for marine spatial planning and coastal development, including use of the coastal zone for offshore wind energy. We present results of interannual changes in seafloor surficial geology at the Redbird artificial reef site, located on the continental shelf offshore of Delaware Bay. The Redbird reef is composed of NYC subway cars, barges, tugboats, and other sunken objects. Since objects were added sporadically between 1996 and 2009, the survey area acts as a natural laboratory to study the evolution of the surrounding seafloor at a structural reef habitat through time. Annual side-scan surveys from 2008 through 2011, and one bathymetric survey in 2010 provide information about surface geology and morphology. Local wave and current data for this time period were analyzed to determine the main morphological agents. Automated backscatter segmentation show that three bottom types dominate and that these large-scale (>10 m) surface sediment patterns persist from year to year. Grab samples reveal that the bottom types are silty sand with clay and sandy gravel. Clear sediment and biological patterns emerged revealing the influence of the objects on the seafloor. Comet-shaped moats of sandy gravel surround single objects and grow to form large-scale coalesced patches around groups of objects. Alignment of sediment patches suggests the periodic hydrodynamic influence of seasonal storms. The abundance and diversity of organisms increases with decreasing clay/silt content. Evidence of scour includes the removal of fine sediments, the formation of moats 1-30 m in diameter and 0.5-1 m deep around the reef objects, and the >1 m settling of objects into the seafloor. Data suggest subway cars reached equilibrium with the environment in 6-7 years, but that larger objects or clusters of objects take a longer time to equilibrate and have farther-reaching effects. Knowledge of local wave and current climate

  10. Resetting predator baselines in coral reef ecosystems

    PubMed Central

    Bradley, Darcy; Conklin, Eric; Papastamatiou, Yannis P.; McCauley, Douglas J.; Pollock, Kydd; Pollock, Amanda; Kendall, Bruce E.; Gaines, Steven D.; Caselle, Jennifer E.

    2017-01-01

    What did coral reef ecosystems look like before human impacts became pervasive? Early efforts to reconstruct baselines resulted in the controversial suggestion that pristine coral reefs have inverted trophic pyramids, with disproportionally large top predator biomass. The validity of the coral reef inverted trophic pyramid has been questioned, but until now, was not resolved empirically. We use data from an eight-year tag-recapture program with spatially explicit, capture-recapture models to re-examine the population size and density of a key top predator at Palmyra atoll, the same location that inspired the idea of inverted trophic biomass pyramids in coral reef ecosystems. Given that animal movement is suspected to have significantly biased early biomass estimates of highly mobile top predators, we focused our reassessment on the most mobile and most abundant predator at Palmyra, the grey reef shark (Carcharhinus amblyrhynchos). We estimated a density of 21.3 (95% CI 17.8, 24.7) grey reef sharks/km2, which is an order of magnitude lower than the estimates that suggested an inverted trophic pyramid. Our results indicate that the trophic structure of an unexploited reef fish community is not inverted, and that even healthy top predator populations may be considerably smaller, and more precarious, than previously thought. PMID:28220895

  11. CORAL REEF BIOLOGICAL CRITERIA: USING THE CLEAN ...

    EPA Pesticide Factsheets

    Coral reefs are declining at unprecedented rates worldwide due to multiple interactive stressors including climate change and land-based sources of pollution. The Clean Water Act (CWA) can be a powerful legal instrument for protecting water resources, including the biological inhabitants of coral reefs. The objective of the CWA is to restore and maintain the chemical, physical and biological integrity of water resources. Coral reef protection and restoration under the Clean Water Act begins with water quality standards - provisions of state or Federal law that consist of a designated use(s) for the waters of the United States and water quality criteria sufficient to protect the uses. Aquatic life use is the designated use that is measured by biological criteria (biocriteria). Biocriteria are expectations set by a jurisdiction for the quality and quantity of living aquatic resources in a defined waterbody. Biocriteria are an important addition to existing management tools for coral reef ecosystems. The Technical Support Document “Coral Reef Biological Criteria: Using the Clean Water Act to Protect a National Treasure” will provide a framework to aid States and Territories in their development, adoption, and implementation of coral reef biocriteria in their respective water quality standards. The Technical Support Document “Coral Reef Biological Criteria: Using the Clean Water Act to Protect a National Treasure” will provide a framework for coral re

  12. Thermite Reaction to Produce Artificial Reefs

    NASA Astrophysics Data System (ADS)

    Trevino, Alexandro; Martirosyan, Karen; Kline, Richard

    The degradation of coral reefs is an ecological issue that has prompted new collaboration by different scientific communities that would assist in the regeneration of the reefs. Unfortunately, these processes can be inefficient and extremely expensive prompting a new scientific approach by using solid-state combustion synthesis to regenerate the reefs. In this report we aimed to consolidate a multi-composite material to produce artificial reefs by initiating thermite reaction based on aluminum and polytetrafluoroethylene (PTFE) with natural reefs. By Thermodynamic analysis and experimentation it was established that a range between .03-.07 number of moles of PTFE was sufficient to reach an adiabatic temperature of over 1900 K, a sustained reaction and a physically stable product was achieved. Reefs are primarily composed of carbonates but their exact chemical composition can vary. X-ray diffraction analysis was used to determine the chemical composition of the reef and revealed presence of oxides, carbonates, silicates. The dominant chemical compounds that were identified are, SiO2 -17%, MgSiO3-14.5%, CaCO3- 11.4%, Ca(Si3O4). Using our thermite reaction we aimed to achieve optimal physical, chemical, and biological properties and maintain cost efficiency of the multi-composite material.

  13. Resetting predator baselines in coral reef ecosystems.

    PubMed

    Bradley, Darcy; Conklin, Eric; Papastamatiou, Yannis P; McCauley, Douglas J; Pollock, Kydd; Pollock, Amanda; Kendall, Bruce E; Gaines, Steven D; Caselle, Jennifer E

    2017-02-21

    What did coral reef ecosystems look like before human impacts became pervasive? Early efforts to reconstruct baselines resulted in the controversial suggestion that pristine coral reefs have inverted trophic pyramids, with disproportionally large top predator biomass. The validity of the coral reef inverted trophic pyramid has been questioned, but until now, was not resolved empirically. We use data from an eight-year tag-recapture program with spatially explicit, capture-recapture models to re-examine the population size and density of a key top predator at Palmyra atoll, the same location that inspired the idea of inverted trophic biomass pyramids in coral reef ecosystems. Given that animal movement is suspected to have significantly biased early biomass estimates of highly mobile top predators, we focused our reassessment on the most mobile and most abundant predator at Palmyra, the grey reef shark (Carcharhinus amblyrhynchos). We estimated a density of 21.3 (95% CI 17.8, 24.7) grey reef sharks/km(2), which is an order of magnitude lower than the estimates that suggested an inverted trophic pyramid. Our results indicate that the trophic structure of an unexploited reef fish community is not inverted, and that even healthy top predator populations may be considerably smaller, and more precarious, than previously thought.

  14. Miocene reef carbonates of Mariana Islands

    SciTech Connect

    Siegrist, H.G. Jr.

    1988-02-01

    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.

  15. Ecological impacts and management implications of reef walking on a tropical reef flat community.

    PubMed

    Williamson, Jane E; Byrnes, Evan E; Clark, Jennalee A; Connolly, David M; Schiller, Sabine E; Thompson, Jessica A; Tosetto, Louise; Martinelli, Julieta C; Raoult, Vincent

    2017-01-30

    Continued growth of tourism has led to concerns about direct and indirect impacts on the ecology of coral reefs and ultimate sustainability of these environments under such pressure. This research assessed impacts of reef walking by tourists on a relatively pristine reef flat community associated with an 'ecoresort' on the Great Barrier Reef, Australia. Heavily walked areas had lower abundances of live hard coral but greater amounts of dead coral and sediment. Abundances of macroalgae were not affected between sites. Coral-associated butterflyfish were less abundant and less diverse in more trampled sites. A manipulative experiment showed handling holothurians on reef walks had lasting negative impacts. This is the first study to show potential impacts of such handling on holothurians. Ecological impacts of reef walking are weighed against sociocultural benefits of a first hand experience in nature.

  16. A regional geochronological study of late pleistocene permafrost

    SciTech Connect

    Kostyukevich, V.V. . Geochemistry Lab.)

    1993-01-01

    The use of radiocarbon dating in geocryological investigations makes it possible to establish a chronology for permafrost-geological development during the Late Pleistocene. Both global and regional time scales for the formation of Late Pleistocene permafrost have been worked out over the past 15--20 years at the Permafrost Institute of the Siberian Branch of Russian Academy of Sciences. He presents here results from study areas of northwestern Siberia and of North, Central and West Yakutia.

  17. Ocean acidification accelerates reef bioerosion.

    PubMed

    Wisshak, Max; Schönberg, Christine H L; Form, Armin; Freiwald, André

    2012-01-01

    In the recent discussion how biotic systems may react to ocean acidification caused by the rapid rise in carbon dioxide partial pressure (pCO(2)) in the marine realm, substantial research is devoted to calcifiers such as stony corals. The antagonistic process - biologically induced carbonate dissolution via bioerosion - has largely been neglected. Unlike skeletal growth, we expect bioerosion by chemical means to be facilitated in a high-CO(2) world. This study focuses on one of the most detrimental bioeroders, the sponge Cliona orientalis, which attacks and kills live corals on Australia's Great Barrier Reef. Experimental exposure to lowered and elevated levels of pCO(2) confirms a significant enforcement of the sponges' bioerosion capacity with increasing pCO(2) under more acidic conditions. Considering the substantial contribution of sponges to carbonate bioerosion, this finding implies that tropical reef ecosystems are facing the combined effects of weakened coral calcification and accelerated bioerosion, resulting in critical pressure on the dynamic balance between biogenic carbonate build-up and degradation.

  18. Ocean Acidification Accelerates Reef Bioerosion

    PubMed Central

    Wisshak, Max; Schönberg, Christine H. L.; Form, Armin; Freiwald, André

    2012-01-01

    In the recent discussion how biotic systems may react to ocean acidification caused by the rapid rise in carbon dioxide partial pressure (pCO2) in the marine realm, substantial research is devoted to calcifiers such as stony corals. The antagonistic process – biologically induced carbonate dissolution via bioerosion – has largely been neglected. Unlike skeletal growth, we expect bioerosion by chemical means to be facilitated in a high-CO2 world. This study focuses on one of the most detrimental bioeroders, the sponge Cliona orientalis, which attacks and kills live corals on Australia’s Great Barrier Reef. Experimental exposure to lowered and elevated levels of pCO2 confirms a significant enforcement of the sponges’ bioerosion capacity with increasing pCO2 under more acidic conditions. Considering the substantial contribution of sponges to carbonate bioerosion, this finding implies that tropical reef ecosystems are facing the combined effects of weakened coral calcification and accelerated bioerosion, resulting in critical pressure on the dynamic balance between biogenic carbonate build-up and degradation. PMID:23028797

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

    PubMed

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

    2014-10-01

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

  20. A Novel Miniaturization Technique of a Microstrip Patch Antenna using Patch Resonators

    NASA Astrophysics Data System (ADS)

    Kakita, Katsutoshi; Morita, Norihiko; Horii, Yasushi

    Microstrip patch antennas have been widely used in mobile and satellite communication systems due to their great advantages of low cost, low profile, lightweight and easy fabrication. However, the dimensions of a classical patch antenna are on the order of half a wavelength. This paper proposes a new approach to reduce the size of the antenna by embedding several patch resonators in an antenna substrate. Periodically installed resonators are expected to exhibit slow-wave effects. First of all, a microstrip delay line having a train of patch resonators in its substrate is demonstrated theoretically by the conventional FDTD method, and the slow-wave effect is discussed. Next, a 2-dimentional patch resonator array is applied to a microstrip patch antenna, and the effectiveness of the proposed structure is evaluated in the respect of antenna dimensions. Also, several experiments have been carried out to confirm the theoretical predictions. Using a prototype model fabricated on an LTCC substrate, the size reduction of more the 50% is attained.

  1. Coral Reef Color: Remote and In-Situ Imaging Spectroscopy of Reef Structure and Function

    NASA Astrophysics Data System (ADS)

    Hochberg, E. J.

    2015-12-01

    Coral reefs are threatened at local to global scales by a litany of anthropogenic impacts, including overfishing, coastal development, marine and watershed pollution, rising ocean temperatures, and ocean acidification. However, available data for the primary indicator of coral reef condition — proportional cover of living coral — are surprisingly sparse and show patterns that contradict the prevailing understanding of how environment impacts reef condition. Remote sensing is the only available tool for acquiring synoptic, uniform data on reef condition at regional to global scales. Discrimination between coral and other reef benthos relies on narrow wavebands afforded by imaging spectroscopy. The same spectral information allows non-invasive quantification of photosynthetic pigment composition, which shows unexpected phenological trends. There is also potential to link biodiversity with optical diversity, though there has been no effort in that direction. Imaging spectroscopy underlies the light-use efficiency model for reef primary production by quantifying light capture, which in turn indicates biochemical capacity for CO2 assimilation. Reef calcification is strongly correlated with primary production, suggesting the possibility for an optics-based model of that aspect of reef function, as well. By scaling these spectral models for use with remote sensing, we can vastly improve our understanding of reef structure, function, and overall condition across regional to global scales. By analyzing those remote sensing products against ancillary environmental data, we can construct secondary models to predict reef futures in the era of global change. This final point is the objective of CORAL (COral Reef Airborne Laboratory), a three-year project funded under NASA's Earth Venture Suborbital-2 program to investigate the relationship between coral reef condition at the ecosystem scale and various nominal biogeophysical forcing parameters.

  2. The impact of large terrestrial carnivores on Pleistocene ecosystems.

    PubMed

    Van Valkenburgh, Blaire; Hayward, Matthew W; Ripple, William J; Meloro, Carlo; Roth, V Louise

    2016-01-26

    Large mammalian terrestrial herbivores, such as elephants, have dramatic effects on the ecosystems they inhabit and at high population densities their environmental impacts can be devastating. Pleistocene terrestrial ecosystems included a much greater diversity of megaherbivores (e.g., mammoths, mastodons, giant ground sloths) and thus a greater potential for widespread habitat degradation if population sizes were not limited. Nevertheless, based on modern observations, it is generally believed that populations of megaherbivores (>800 kg) are largely immune to the effects of predation and this perception has been extended into the Pleistocene. However, as shown here, the species richness of big carnivores was greater in the Pleistocene and many of them were significantly larger than their modern counterparts. Fossil evidence suggests that interspecific competition among carnivores was relatively intense and reveals that some individuals specialized in consuming megaherbivores. To estimate the potential impact of Pleistocene large carnivores, we use both historic and modern data on predator-prey body mass relationships to predict size ranges of their typical and maximum prey when hunting as individuals and in groups. These prey size ranges are then compared with estimates of juvenile and subadult proboscidean body sizes derived from extant elephant growth data. Young proboscideans at their most vulnerable age fall within the predicted prey size ranges of many of the Pleistocene carnivores. Predation on juveniles can have a greater impact on megaherbivores because of their long interbirth intervals, and consequently, we argue that Pleistocene carnivores had the capacity to, and likely did, limit megaherbivore population sizes.

  3. The impact of large terrestrial carnivores on Pleistocene ecosystems

    PubMed Central

    Van Valkenburgh, Blaire; Ripple, William J.; Meloro, Carlo; Roth, V. Louise

    2016-01-01

    Large mammalian terrestrial herbivores, such as elephants, have dramatic effects on the ecosystems they inhabit and at high population densities their environmental impacts can be devastating. Pleistocene terrestrial ecosystems included a much greater diversity of megaherbivores (e.g., mammoths, mastodons, giant ground sloths) and thus a greater potential for widespread habitat degradation if population sizes were not limited. Nevertheless, based on modern observations, it is generally believed that populations of megaherbivores (>800 kg) are largely immune to the effects of predation and this perception has been extended into the Pleistocene. However, as shown here, the species richness of big carnivores was greater in the Pleistocene and many of them were significantly larger than their modern counterparts. Fossil evidence suggests that interspecific competition among carnivores was relatively intense and reveals that some individuals specialized in consuming megaherbivores. To estimate the potential impact of Pleistocene large carnivores, we use both historic and modern data on predator–prey body mass relationships to predict size ranges of their typical and maximum prey when hunting as individuals and in groups. These prey size ranges are then compared with estimates of juvenile and subadult proboscidean body sizes derived from extant elephant growth data. Young proboscideans at their most vulnerable age fall within the predicted prey size ranges of many of the Pleistocene carnivores. Predation on juveniles can have a greater impact on megaherbivores because of their long interbirth intervals, and consequently, we argue that Pleistocene carnivores had the capacity to, and likely did, limit megaherbivore population sizes. PMID:26504224

  4. Pleistocene megafaunal interaction networks became more vulnerable after human arrival.

    PubMed

    Pires, Mathias M; Koch, Paul L; Fariña, Richard A; de Aguiar, Marcus A M; dos Reis, Sérgio F; Guimarães, Paulo R

    2015-09-07

    The end of the Pleistocene was marked by the extinction of almost all large land mammals worldwide except in Africa. Although the debate on Pleistocene extinctions has focused on the roles of climate change and humans, the impact of perturbations depends on properties of ecological communities, such as species composition and the organization of ecological interactions. Here, we combined palaeoecological and ecological data, food-web models and community stability analysis to investigate if differences between Pleistocene and modern mammalian assemblages help us understand why the megafauna died out in the Americas while persisting in Africa. We show Pleistocene and modern assemblages share similar network topology, but differences in richness and body size distributions made Pleistocene communities significantly more vulnerable to the effects of human arrival. The structural changes promoted by humans in Pleistocene networks would have increased the likelihood of unstable dynamics, which may favour extinction cascades in communities facing extrinsic perturbations. Our findings suggest that the basic aspects of the organization of ecological communities may have played an important role in major extinction events in the past. Knowledge of community-level properties and their consequences to dynamics may be critical to understand past and future extinctions.

  5. Pleistocene phylogeographic effects on avian populations and the speciation process.

    PubMed Central

    Avise, J C; Walker, D

    1998-01-01

    Pleistocene biogeographic events have traditionally been ascribed a major role in promoting speciations and in sculpting the present-day diversity and distributions of vertebrate taxa. However, this paradigm has recently come under challenge from a review of interspecific mtDNA genetic distances in birds: most sister-species separations dated to the Pliocene. Here we summarize the literature on intraspecific mtDNA phylogeographic patterns in birds and reinterpret the molecular evidence bearing on Pleistocene influences. At least 37 of the 63 avian species surveyed (59%) are sundered into recognizable phylogeographic units, and 28 of these separations (76%) trace to the Pleistocene. Furthermore, use of phylogroup separation times within species as minimum estimates of 'speciation durations' also indicates that many protracted speciations, considered individually, probably extended through time from Pliocene origins to Pleistocene completions. When avian speciation is viewed properly as an extended temporal process rather than as a point event, Pleistocene conditions appear to have played an active role both in initiating major phylogeographic separations within species, and in completing speciations that had been inaugurated earlier. Whether the Pleistocene was exceptional in these regards compared with other geological times remains to be determined. PMID:9569664

  6. USGS research on Atlantic coral reef ecosystems

    USGS Publications Warehouse

    Kuffner, Ilsa B.; Yates, Kimberly K.; Zawada, David G.; Richey, Julie N.; Kellogg, Christina A.; Toth, Lauren T.

    2015-10-23

    Coral reefs are massive, biomineralized structures that protect coastal communities by acting as barriers to hazards such as hurricanes and tsunamis. They provide sand for beaches through the natural process of erosion, support tourism and recreational industries, and provide essential habitat for fisheries. The continuing global degradation of coral reef ecosystems is well documented. There is a need for focused, coordinated science to understand the complex physical and biological processes and interactions that are impacting the condition of coral reefs and their ability to respond to a changing environment.

  7. NORTHWEST OBLIQUE AERIAL VIEW OF FORT DELAWARE AND PEA PATCH ...

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

    NORTHWEST OBLIQUE AERIAL VIEW OF FORT DELAWARE AND PEA PATCH ISLAND. REMAINS OF SEA WALL VISIBLE IN FOREGROUND AND RIGHT OF IMAGE - Fort Delaware, Pea Patch Island, Delaware City, New Castle County, DE

  8. Performance Analysis of Coaxial Fed Stacked Patch Antennas

    NASA Astrophysics Data System (ADS)

    Jain, Satish K.; Jain, Shobha

    2014-01-01

    A performance analysis of coaxial fed stacked dual patch electromagnetic-coupled microstrip antenna useful for satellite communication working in X/Ku band is presented. A simplified structure of stacked dual patch antenna is proposed with adjustable foam-gap between patches. Few important geometrical parameters were chosen on which the performance of stacked dual patch antenna mainly depends. Dimension of lower square patch, upper square patch and height of foam-gap between two patches are the parameters, which were varied one by one keeping other parameters constant. The performance was observed through the reflection coefficient (dB) and smith chart impedance plot, obtained from the numerical simulator (IE3D) for the dual resonance frequency and bandwidth. Proposed geometry of stacked dual patch antenna was also analyzed with cavity model and artificial neural network modeling technique. Dual resonance frequencies and associated bandwidth were calculated through them and results were cross checked in the laboratory with a few experimental findings.

  9. Understanding the murky history of the Coral Triangle: Miocene corals and reef habitats in East Kalimantan (Indonesia)

    NASA Astrophysics Data System (ADS)

    Santodomingo, Nadiezhda; Renema, Willem; Johnson, Kenneth G.

    2016-09-01

    Studies on ancient coral communities living in marginal conditions, including low light, high turbidity, extreme temperatures, or high nutrients, are important to understand the current structure of reefs and how they could potentially respond to global changes. The main goal of this study was to document the rich and well-preserved fossil coral fauna preserved in Miocene exposures of the Kutai Basin in East Kalimantan, Indonesia. Our collections include almost forty thousand specimens collected from 47 outcrops. Seventy-nine genera and 234 species have been identified. Three different coral assemblages were found corresponding to small patch reefs that developed under the influence of high siliciclastic inputs from the Mahakam Delta. Coral assemblages vary in richness, structure, and composition. Platy coral assemblages were common until the Serravallian (Middle Miocene), while branching coral assemblages became dominant in the Tortonian (Late Miocene). By the late Tortonian massive coral assemblages dominated, similar to modern-style coral framework. Our results suggest that challenging habitats, such as the Miocene turbid habitats of East Kalimantan, might have played an important role during the early diversification of the Coral Triangle by hosting a pool of resilient species more likely to survive the environmental changes that have affected this region since the Cenozoic. Further research that integrates fossil and recent turbid habitats may provide a glimpse into the dynamics and future of coral reefs as "typical" clear-water reefs continue to decline in most regions.

  10. Geomorphology and late Holocene accretion history of Adele Reef: a northwest Australian mid-shelf platform reef

    NASA Astrophysics Data System (ADS)

    Solihuddin, Tubagus; Bufarale, Giada; Blakeway, David; O'Leary, Michael J.

    2016-12-01

    The mid-shelf reefs of the Kimberley Bioregion are one of Australia's more remote tropical reef provinces and such have received little attention from reef researchers. This study describes the geomorphology and late Holocene accretion history of Adele Reef, a mid-shelf platform reef, through remote sensing of contemporary reef habitats, shallow seismic profiling, shallow percussion coring and radiocarbon dating. Seismic profiling indicates that the Holocene reef sequence is 25 to 35 m thick and overlies at least three earlier stages of reef build-up, interpreted as deposited during marine isotope stages 5, 7 and 9 respectively. The cored shallow subsurface facies of Adele Reef are predominantly detrital, comprising small coral colonies and fragments in a sandy matrix. Reef cores indicate a `catch-up' growth pattern, with the reef flat being approximately 5-10 m deep when sea level stabilised at its present elevation 6,500 years BP. The reef flat is rimmed by a broad low-relief reef crest only 10-20 cm high, characterised by anastomosing ridges of rhodoliths and coralliths. The depth of the Holocene/last interglacial contact (25-30 m) suggests a subsidence rate of 0.2 mm/year for Adele Reef since the last interglacial. This value, incorporated with subsidence rates from Cockatoo Island (inshore) and Scott Reefs (offshore), provides the first quantitative estimate of hinge subsidence for the Kimberley coast and adjacent shelf, with progressively greater subsidence across the shelf.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  12. Ecological solutions to reef degradation: optimizing coral reef restoration in the Caribbean and Western Atlantic

    PubMed Central

    2016-01-01

    Reef restoration activities have proliferated in response to the need to mitigate coral declines and recover lost reef structure, function, and ecosystem services. Here, we describe the recent shift from costly and complex engineering solutions to recover degraded reef structure to more economical and efficient ecological approaches that focus on recovering the living components of reef communities. We review the adoption and expansion of the coral gardening framework in the Caribbean and Western Atlantic where practitioners now grow and outplant 10,000’s of corals onto degraded reefs each year. We detail the steps for establishing a gardening program as well as long-term goals and direct and indirect benefits of this approach in our region. With a strong scientific basis, coral gardening activities now contribute significantly to reef and species recovery, provide important scientific, education, and outreach opportunities, and offer alternate livelihoods to local stakeholders. While challenges still remain, the transition from engineering to ecological solutions for reef degradation has opened the field of coral reef restoration to a wider audience poised to contribute to reef conservation and recovery in regions where coral losses and recruitment bottlenecks hinder natural recovery. PMID:27781176

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

    PubMed

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

    2013-09-01

    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.

  14. Exploring the hidden shallows: extensive reef development and resilience within the turbid nearshore Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Morgan, Kyle; Perry, Chris; Smithers, Scott; Johnson, Jamie; Daniell, James

    2016-04-01

    Mean coral cover on Australia's Great Barrier Reef (GBR) has reportedly declined by over 15% during the last 30 years. Climate change events and outbreaks of coral disease have been major drivers of degradation, often exacerbating the stresses caused by localised human activities (e.g. elevated sediment and nutrient inputs). Here, however, in the first assessment of nearshore reef occurrence and ecology across meaningful spatial scales (15.5 sq km), we show that areas of the GBR shelf have exhibited strong intra-regional variability in coral resilience to declining water quality. Specifically, within the highly-turbid "mesophotic" nearshore (<10 m depth) of the central GBR, where terrigenous seafloor sediments are persistently resuspended by wave processes, coral cover averages 38% (twice that reported on mid- and outer-shelf reefs). Of the mapped area, 11% of the seafloor has distinct reef or coral community cover, a density comparable to that measured across the entire GBR shelf (9%). Identified coral taxa (21 genera) exhibited clear depth-stratification corresponding closely to light attenuation and seafloor topography. Reefs have accreted relatively rapidly during the late-Holocene (1.8-3.0 mm y-1) with rates of vertical reef growth influenced by intrinsic shifts in coral assemblages associated with reef development. Indeed, these shallow-water reefs may have similar potential as refugia from large-scale disturbance as their deep-water (>30 m) "mesophotic" equivalents, and also provide a basis from which to model future trajectories of reef growth within nearshore areas.

  15. Ecological solutions to reef degradation: optimizing coral reef restoration in the Caribbean and Western Atlantic.

    PubMed

    Lirman, Diego; Schopmeyer, Stephanie

    2016-01-01

    Reef restoration activities have proliferated in response to the need to mitigate coral declines and recover lost reef structure, function, and ecosystem services. Here, we describe the recent shift from costly and complex engineering solutions to recover degraded reef structure to more economical and efficient ecological approaches that focus on recovering the living components of reef communities. We review the adoption and expansion of the coral gardening framework in the Caribbean and Western Atlantic where practitioners now grow and outplant 10,000's of corals onto degraded reefs each year. We detail the steps for establishing a gardening program as well as long-term goals and direct and indirect benefits of this approach in our region. With a strong scientific basis, coral gardening activities now contribute significantly to reef and species recovery, provide important scientific, education, and outreach opportunities, and offer alternate livelihoods to local stakeholders. While challenges still remain, the transition from engineering to ecological solutions for reef degradation has opened the field of coral reef restoration to a wider audience poised to contribute to reef conservation and recovery in regions where coral losses and recruitment bottlenecks hinder natural recovery.

  16. CoBOP Coral Reefs: Optical Closure of a Coral Reef Submarine Light Field

    DTIC Science & Technology

    2003-09-30

    CoBOP Coral Reefs : Optical Closure of a Coral Reef Submarine Light Field Dr. Charles S. Yentsch Bigelow Laboratory McKown Point Road West...number. 1. REPORT DATE 30 SEP 2003 2. REPORT TYPE 3. DATES COVERED 00-00-2003 to 00-00-2003 4. TITLE AND SUBTITLE CoBOP Coral Reefs : Optical...Closure of a Coral Reef Submarine Light Field 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e

  17. [Responses of Caragana seed pests to host plant patch quality and patch pattern in desert regions of Ningxia, Northwest China].

    PubMed

    Zhang, Da-zhi; He, Da-han

    2011-07-01

    Taking the desert landscape in mid-eastern Ningxia of Northeast China as the background, eighteen patches of Caragana shrub lands (natural or manned) with the habitat types of manually-fixed sandy land, mobile sandy land, and silty-loam downland were selected as study sites to investigate the responses of three Caragana seed pest species (Kytorhinus immixtus, Etiella zinckenella, and Bruchophagus neocaraganae) to the host plant patch quality, patch area, and patch spatial pattern. The damaged rate of host plant by the pests had close relations to the patch quality, patch pattern, and the transferring capability of the pests. The responses of the pests to patch quality were affected by patch scale, and among the three habitat types, manually-fixed sandy land had the highest damaged rate, followed by mobile sandy land, and silty-loam downland, with significant differences among them (P<0.05). In small scale patch pattern, there existed definite correlations between the pest number and the patch area and its fragmentation degree. The decrease of patch area and the increase of the fragmentation degree reduced the damage rate of high transferring capability Etiella zinckenella (r = 0.365), but had less effects on low transferring capability K. immixtus (r = 0.160) and B. neocaraganae (r = 0.193). The strength of patch edge effect and the mutual complement of the resources around patches had positive effects on the population density of the pests.

  18. Corridor Length and Patch Colonization by a Butterfly, Junonia coenia

    SciTech Connect

    Haddad, N.

    1999-01-22

    Study hypothesized that corridors increase patch colonization by Junonia coenia regardless of insects initial distance from patch, as the butterfly is known to move between patches preferentially through corridors. Neither corridor nor distance had significant effect on patch colonization, but significant interaction between presence or absence of corridors and distance. One critical factor is interpatch distance which may determine the relative effectiveness of corridors and other landscape configurations.

  19. Novel Metamaterials for Patch Antennas Applications

    NASA Astrophysics Data System (ADS)

    Zervos, Theodore; Lazarakis, Fotis; Alexandridis, Antonis; Dangakis, Kostas; Stamopoulos, Dimosthenis; Pissas, Michalis

    In this paper we introduce the incorporation of magneto-electric materials into antenna design and the potential of controlling the behavior of the antenna by means of an external magnetic field. After an intensive study of magneto-electric material properties, a ferrimagnetic compound called Yttrium Iron Garnet (YIG) was found to be the best candidate for the novel antenna design. We provide a metamaterial patch antenna design where a part of the substrate is replaced by the YIG compound. After several design modifications the final model includes a circular-shaped YIG substrate just under the metallic patch and offers sufficient performance in terms of resonance, bandwidth and radiation efficiency. Additionally, in the presence of an external magnetic field the polarization becomes elliptical and the sense of the polarization (left or right) can be controlled through the direction of the magnetic field. That latter characteristic confirms the metamaterial-nature of the antenna.

  20. Mesh saliency with adaptive local patches

    NASA Astrophysics Data System (ADS)

    Nouri, Anass; Charrier, Christophe; Lézoray, Olivier

    2015-03-01

    3D object shapes (represented by meshes) include both areas that attract the visual attention of human observers and others less or not attractive at all. This visual attention depends on the degree of saliency exposed by these areas. In this paper, we propose a technique for detecting salient regions in meshes. To do so, we define a local surface descriptor based on local patches of adaptive size and filled with a local height field. The saliency of mesh vertices is then defined as its degree measure with edges weights computed from adaptive patch similarities. Our approach is compared to the state-of-the-art and presents competitive results. A study evaluating the influence of the parameters establishing this approach is also carried out. The strength and the stability of our approach with respect to noise and simplification are also studied.

  1. Pleistocene cave art from Sulawesi, Indonesia.

    PubMed

    Aubert, M; Brumm, A; Ramli, M; Sutikna, T; Saptomo, E W; Hakim, B; Morwood, M J; van den Bergh, G D; Kinsley, L; Dosseto, A

    2014-10-09

    Archaeologists have long been puzzled by the appearance in Europe ∼40-35 thousand years (kyr) ago of a rich corpus of sophisticated artworks, including parietal art (that is, paintings, drawings and engravings on immobile rock surfaces) and portable art (for example, carved figurines), and the absence or scarcity of equivalent, well-dated evidence elsewhere, especially along early human migration routes in South Asia and the Far East, including Wallacea and Australia, where modern humans (Homo sapiens) were established by 50 kyr ago. Here, using uranium-series dating of coralloid speleothems directly associated with 12 human hand stencils and two figurative animal depictions from seven cave sites in the Maros karsts of Sulawesi, we show that rock art traditions on this Indonesian island are at least compatible in age with the oldest European art. The earliest dated image from Maros, with a minimum age of 39.9 kyr, is now the oldest known hand stencil in the world. In addition, a painting of a babirusa ('pig-deer') made at least 35.4 kyr ago is among the earliest dated figurative depictions worldwide, if not the earliest one. Among the implications, it can now be demonstrated that humans were producing rock art by ∼40 kyr ago at opposite ends of the Pleistocene Eurasian world.

  2. Corridor Length and Patch Colonization by a Butterfly Junonia coenia

    SciTech Connect

    Nick Haddad

    2000-06-01

    Habitat corridors have been proposed to reduce patch isolation and increase population persistence in fragmented landscapes. This study tested whether patch colonization was increased by the presence and various length corridors. The specific butterfly species tested has been shown to use corridors, however, the results indicate that neither the distance between patches or the presence of a corridor influenced colonization.

  3. The influence of sea level and cyclones on Holocene reef flat development: Middle Island, central Great Barrier Reef

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    The geomorphology and chronostratigraphy of the reef flat (including microatoll ages and elevations) were investigated to better understand the long-term development of the reef at Middle Island, inshore central Great Barrier Reef. Eleven cores across the fringing reef captured reef initiation, framework accretion and matrix sediments, allowing a comprehensive appreciation of reef development. Precise uranium-thorium ages obtained from coral skeletons revealed that the reef initiated ~7873 ± 17 years before present (yBP), and most of the reef was emplaced in the following 1000 yr. Average rates of vertical reef accretion ranged between 3.5 and 7.6 mm yr-1. Reef framework was dominated by branching corals ( Acropora and Montipora). An age hiatus of ~5000 yr between 6439 ± 19 and 1617 ± 10 yBP was observed in the core data and attributed to stripping of the reef structure by intense cyclones during the mid- to late-Holocene. Large shingle ridges deposited onshore and basset edges preserved on the reef flat document the influence of cyclones at Middle Island and represent potential sinks for much of the stripped material. Stripping of the upper reef structure around the outer margin of the reef flat by cyclones created accommodation space for a thin (<1.2 m) veneer of reef growth after 1617 ± 10 yBP that grew over the eroded mid-Holocene reef structure. Although limited fetch and open-water exposure might suggest the reef flat at Middle Island is quite protected, our results show that high-energy waves presumably generated by cyclones have significantly influenced both Holocene reef growth and contemporary reef flat geomorphology.

  4. Patch Finder Plus (PFplus): a web server for extracting and displaying positive electrostatic patches on protein surfaces.

    PubMed

    Shazman, Shula; Celniker, Gershon; Haber, Omer; Glaser, Fabian; Mandel-Gutfreund, Yael

    2007-07-01

    Positively charged electrostatic patches on protein surfaces are usually indicative of nucleic acid binding interfaces. Interestingly, many proteins which are not involved in nucleic acid binding possess large positive patches on their surface as well. In some cases, the positive patches on the protein are related to other functional properties of the protein family. PatchFinderPlus (PFplus) http://pfp.technion.ac.il is a web-based tool for extracting and displaying continuous electrostatic positive patches on protein surfaces. The input required for PFplus is either a four letter PDB code or a protein coordinate file in PDB format, provided by the user. PFplus computes the continuum electrostatics potential and extracts the largest positive patch for each protein chain in the PDB file. The server provides an output file in PDB format including a list of the patch residues. In addition, the largest positive patch is displayed on the server by a graphical viewer (Jmol), using a simple color coding.

  5. Optimal patch code design via device characterization

    NASA Astrophysics Data System (ADS)

    Wu, Wencheng; Dalal, Edul N.

    2012-01-01

    In many color measurement applications, such as those for color calibration and profiling, "patch code" has been used successfully for job identification and automation to reduce operator errors. A patch code is similar to a barcode, but is intended primarily for use in measurement devices that cannot read barcodes due to limited spatial resolution, such as spectrophotometers. There is an inherent tradeoff between decoding robustness and the number of code levels available for encoding. Previous methods have attempted to address this tradeoff, but those solutions have been sub-optimal. In this paper, we propose a method to design optimal patch codes via device characterization. The tradeoff between decoding robustness and the number of available code levels is optimized in terms of printing and measurement efforts, and decoding robustness against noises from the printing and measurement devices. Effort is drastically reduced relative to previous methods because print-and-measure is minimized through modeling and the use of existing printer profiles. Decoding robustness is improved by distributing the code levels in CIE Lab space rather than in CMYK space.

  6. Nanowired three-dimensional cardiac patches

    NASA Astrophysics Data System (ADS)

    Dvir, Tal; Timko, Brian P.; Brigham, Mark D.; Naik, Shreesh R.; Karajanagi, Sandeep S.; Levy, Oren; Jin, Hongwei; Parker, Kevin K.; Langer, Robert; Kohane, Daniel S.

    2011-11-01

    Engineered cardiac patches for treating damaged heart tissues after a heart attack are normally produced by seeding heart cells within three-dimensional porous biomaterial scaffolds. These biomaterials, which are usually made of either biological polymers such as alginate or synthetic polymers such as poly(lactic acid) (PLA), help cells organize into functioning tissues, but poor conductivity of these materials limits the ability of the patch to contract strongly as a unit. Here, we show that incorporating gold nanowires within alginate scaffolds can bridge the electrically resistant pore walls of alginate and improve electrical communication between adjacent cardiac cells. Tissues grown on these composite matrices were thicker and better aligned than those grown on pristine alginate and when electrically stimulated, the cells in these tissues contracted synchronously. Furthermore, higher levels of the proteins involved in muscle contraction and electrical coupling are detected in the composite matrices. It is expected that the integration of conducting nanowires within three-dimensional scaffolds may improve the therapeutic value of current cardiac patches.

  7. Modular assembly of thick multifunctional cardiac patches

    PubMed Central

    Fleischer, Sharon; Shapira, Assaf; Feiner, Ron; Dvir, Tal

    2017-01-01

    In cardiac tissue engineering cells are seeded within porous biomaterial scaffolds to create functional cardiac patches. Here, we report on a bottom-up approach to assemble a modular tissue consisting of multiple layers with distinct structures and functions. Albumin electrospun fiber scaffolds were laser-patterned to create microgrooves for engineering aligned cardiac tissues exhibiting anisotropic electrical signal propagation. Microchannels were patterned within the scaffolds and seeded with endothelial cells to form closed lumens. Moreover, cage-like structures were patterned within the scaffolds and accommodated poly(lactic-co-glycolic acid) (PLGA) microparticulate systems that controlled the release of VEGF, which promotes vascularization, or dexamethasone, an anti-inflammatory agent. The structure, morphology, and function of each layer were characterized, and the tissue layers were grown separately in their optimal conditions. Before transplantation the tissue and microparticulate layers were integrated by an ECM-based biological glue to form thick 3D cardiac patches. Finally, the patches were transplanted in rats, and their vascularization was assessed. Because of the simple modularity of this approach, we believe that it could be used in the future to assemble other multicellular, thick, 3D, functional tissues. PMID:28167795

  8. Oysters and Oyster Reef Communities in Florida.

    ERIC Educational Resources Information Center

    Knight, Jean; Bly, Joe

    1989-01-01

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

  9. Reef Ecosystem Services and Decision Support Database

    EPA Science Inventory

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

  10. Plate tectonics drive tropical reef biodiversity dynamics

    NASA Astrophysics Data System (ADS)

    Leprieur, Fabien; Descombes, Patrice; Gaboriau, Théo; Cowman, Peter F.; Parravicini, Valeriano; Kulbicki, Michel; Melián, Carlos J.; de Santana, Charles N.; Heine, Christian; Mouillot, David; Bellwood, David R.; Pellissier, Loïc

    2016-05-01

    The Cretaceous breakup of Gondwana strongly modified the global distribution of shallow tropical seas reshaping the geographic configuration of marine basins. However, the links between tropical reef availability, plate tectonic processes and marine biodiversity distribution patterns are still unknown. Here, we show that a spatial diversification model constrained by absolute plate motions for the past 140 million years predicts the emergence and movement of diversity hotspots on tropical reefs. The spatial dynamics of tropical reefs explains marine fauna diversification in the Tethyan Ocean during the Cretaceous and early Cenozoic, and identifies an eastward movement of ancestral marine lineages towards the Indo-Australian Archipelago in the Miocene. A mechanistic model based only on habitat-driven diversification and dispersal yields realistic predictions of current biodiversity patterns for both corals and fishes. As in terrestrial systems, we demonstrate that plate tectonics played a major role in driving tropical marine shallow reef biodiversity dynamics.

  11. Ocean acidification impairs vermetid reef recruitment

    PubMed Central

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

    2014-01-01

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

  12. Fine sediments suppress detritivory on coral reefs.

    PubMed

    Tebbett, Sterling B; Goatley, Christopher H R; Bellwood, David R

    2017-01-30

    Increasing sediment inputs are recognised as an important factor leading to coral reef degradation. However, the role of sediments in ecological processes is poorly understood. This study used paired-choice trials to quantify the effects of sediment grain size and chemical composition on feeding by the abundant detritivorous reef fish, Ctenochaetus striatus. The size of sediments from algal turfs were also compared to those ingested by reef-dwelling C. striatus. Algal turfs containing coarser sediments were preferred by C. striatus, while sediment composition (reefal carbonates vs. riverine silicates) had little effect. On the reef, C. striatus ingested finer sediments than those present in algal turfs. C. striatus appears to prefer algal turfs with coarser sediments as this facilitates ingestion of fine detrital particles, while finer sediments prevent selective feeding on detritus. These findings suggest that fine sediments from terrestrial runoff or dredging may be detrimental to feeding by detritivorous species.

  13. Plate tectonics drive tropical reef biodiversity dynamics.

    PubMed

    Leprieur, Fabien; Descombes, Patrice; Gaboriau, Théo; Cowman, Peter F; Parravicini, Valeriano; Kulbicki, Michel; Melián, Carlos J; de Santana, Charles N; Heine, Christian; Mouillot, David; Bellwood, David R; Pellissier, Loïc

    2016-05-06

    The Cretaceous breakup of Gondwana strongly modified the global distribution of shallow tropical seas reshaping the geographic configuration of marine basins. However, the links between tropical reef availability, plate tectonic processes and marine biodiversity distribution patterns are still unknown. Here, we show that a spatial diversification model constrained by absolute plate motions for the past 140 million years predicts the emergence and movement of diversity hotspots on tropical reefs. The spatial dynamics of tropical reefs explains marine fauna diversification in the Tethyan Ocean during the Cretaceous and early Cenozoic, and identifies an eastward movement of ancestral marine lineages towards the Indo-Australian Archipelago in the Miocene. A mechanistic model based only on habitat-driven diversification and dispersal yields realistic predictions of current biodiversity patterns for both corals and fishes. As in terrestrial systems, we demonstrate that plate tectonics played a major role in driving tropical marine shallow reef biodiversity dynamics.

  14. 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 ...

  15. Quaternary coral reef refugia preserved fish diversity.

    PubMed

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

    2014-05-30

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

  16. Plate tectonics drive tropical reef biodiversity dynamics

    PubMed Central

    Leprieur, Fabien; Descombes, Patrice; Gaboriau, Théo; Cowman, Peter F.; Parravicini, Valeriano; Kulbicki, Michel; Melián, Carlos J.; de Santana, Charles N.; Heine, Christian; Mouillot, David; Bellwood, David R.; Pellissier, Loïc

    2016-01-01

    The Cretaceous breakup of Gondwana strongly modified the global distribution of shallow tropical seas reshaping the geographic configuration of marine basins. However, the links between tropical reef availability, plate tectonic processes and marine biodiversity distribution patterns are still unknown. Here, we show that a spatial diversification model constrained by absolute plate motions for the past 140 million years predicts the emergence and movement of diversity hotspots on tropical reefs. The spatial dynamics of tropical reefs explains marine fauna diversification in the Tethyan Ocean during the Cretaceous and early Cenozoic, and identifies an eastward movement of ancestral marine lineages towards the Indo-Australian Archipelago in the Miocene. A mechanistic model based only on habitat-driven diversification and dispersal yields realistic predictions of current biodiversity patterns for both corals and fishes. As in terrestrial systems, we demonstrate that plate tectonics played a major role in driving tropical marine shallow reef biodiversity dynamics. PMID:27151103

  17. 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...

  18. Extinction vulnerability of coral reef fishes

    PubMed Central

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

    2011-01-01

    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

  19. Ocean acidification impairs vermetid reef recruitment

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  20. Observations of spatial flow patterns at the coral colony scale on a shallow reef flat

    NASA Astrophysics Data System (ADS)

    Hench, James L.; Rosman, Johanna H.

    2013-03-01

    Although small-scale spatial flow variability can affect both larger-scale circulation patterns and biological processes on coral reefs, there are few direct measurements of spatial flow patterns across horizontal scales <100 m. Here flow patterns on a shallow reef flat were measured at scales from a single colony to several adjacent colonies using an array of acoustic Doppler velocimeters on a diver-operated traverse. We observed recirculation zones immediately behind colonies, reduced currents and elevated dissipation rates in turbulent wakes up to 2 colony diameters downstream and enhanced Reynolds stresses in shear layers around wake peripheries. Flow acceleration zones were observed above and between colonies. Coherent flow structures varied with incident flow speeds; recirculation zones were stronger and wakes were more turbulent in faster flows. Low-frequency (<0.03 Hz) flow variations, for which water excursions were large compared with the colony diameters (Keulegan-Carpenter number, KC >1), had similar spatial patterns to wakes, while higher-frequency variations (0.05-0.1 Hz, KC < 1) had no observable spatial structure. On the reef flat, both drag and inertial forces exerted by coral colonies could have significant effects on flow, but within different frequency ranges; drag dominates for low-frequency flow variations and inertial forces dominate for higher-frequency variations, including the wave band. Our scaling analyses suggest that spatial flow patterns at colony and patch scales could have important implications for both physica