596 research outputs found

    Mouthless Cypriniform Fishes from Louisiana and Arkansas

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    No abstract is provided for this brief article

    Site-Dependent Differences in Artificial Reef Function: Implications for Coral Reef Restoration

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    There is an increasing use of artificial structure in coral reef restoration (for references, see Spieler et al., this volume). Often artificial reef structures are chosen for a restoration project simply because they were used elsewhere. However, it is questionable whether the results obtained at one restoration site can be extrapolated to another. In recent years, several studies have examined the effect of artificial reef site selection on formation of associated fish, algae, and/or invertebrate assemblages (Alevizon et al., 1985; Blinova et al., 1994; Bombace et al., 1994; Caley and St. John, 1996; Chang, 1985; Haughton and Aiken, 1989; Hixon and Beets, 1989; Jara and Cespedes, 1994; Kruer and Causey, 1992; Lozano-Alvarez et al., 1994; Moffitt et al., 1989; Relini et al., 1994; Sherman et al., 2000; Sherman et al., 1999; Sogard, 1989; Spieler, 1998; Tomascik, 1991). Although not designed specifically as coral reef restoration projects, the results of these studies lend insight into the problems of restoration. This paper is an overview of recent literature on site selection intended for resource managers interested in using artificial reefs in coral reef restoration. To that end, we re-examined the data from several studies comparing similar artificial reef structures at different sites

    Artificial Substrate and Coral Reef Restoration: What Do We Need to Know to Know What We Need

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    To use artificial substrate effectively in coral reef restoration certain basic knowledge is required: (1) what is the artificial substrate expected to accomplish relative to the goals of the restoration effort and (2) what are the expected interactions of the selected substrate’s composition, texture, orientation, and design with the damaged environment and the biota of interest. Whereas the first point is usually clear, at least in general terms, the second is not. In this review, we examine: the functions of artificial substrate in restoration and some of the physical (i.e., composition; surface texture; color and chemistry; and design in terms of profile, shelter, shading, size and configuration, settlement attractants, and stability) and environmental factors (i.e., temperature, light sedimentation, surround biota, hydrodynamics, depth, and temporal effects) affecting these functions. We conclude that until substantial additional research is accomplished, the use of artificial substrate in coral reef restoration will remain a ‘best guess’ endeavor. Areas requiring additional research are identified and some potentially promising lines of inquiry are suggested

    Reef Fish Assemblage Structure Affected by Small-Scale Spacing and Size Variations of Artificial Patch Reefs

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    To examine how varying the distance between patch reefs affects reef fish assemblage structure, replicate concrete reef modules (∼ 1 m3 each) were deployed on sand bottom at 8 m depth off Ft. Lauderdale, Florida, USA (26°07N, 80°05W). Modules were positioned at the apices of one of four differently sized equilateral triangles. Triangular configurations had side lengths of: 25 m, 15 m, 5 m, and 0.33 m; each treatment with two replicates. Two additional configurations: (1) a solitary module (Single) and (2) two modules side by side (Double), also with two replicates, were deployed in order to examine the interaction of reef size with fish assemblages. SCUBA divers censused fishes monthly, for 2 years, recording the species present, their abundance and sizes (TL). Fishes were assigned to one of five length categories: \u3c 2 cm, \u3e 2–5 cm, \u3e 5–10 cm, \u3e 10–20 cm, and \u3e 20 cm. In general and excluding the smallest three-module spacing treatment (0.33 m treatment), which may have provided unique treatment-specific refuge, total fish abundance and richness were shown to increase when isolation distance increased. However, there were also species-specific and size class differences in response to isolation distance. The second part of this study indicated varying reef size, by doubling and tripling the number of reef modules, increased total fish abundance and species richness. Nevertheless, fish abundance and species richness did not change by an identical multiplier (e.g., doubling modules ≠ double abundance). These results suggest that scientists and marine managers alike should consider reef size and isolation as habitat attributes capable of altering the structure and dynamics of reef fish assemblages

    Marine Biological Monitoring in Broward County, Florida: Year 2 Annual Report

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    A study has been undertaken to monitor Broward County, Florida (southeast Florida) coral communities, reef fish assemblages and sedimentation rates in relation to possible effects from a proposed extensive beach renourishment (restoration) project. Coral communities and reef fish assemblages will be monitored at a total of 23 stations distributed offshore Broward County. This monitoring effort will characterize and quantify populations of scleractinian (stony) corals, octocorallian (gorgonian) corals, sponges, and reef fishes. In addition, sediment traps located at each station will be sampled and analyzed. This document reports the data collected during the second year of this project. Coral communities and fish assemblages were monitored at each of the 23 sites between September and October 2001. In addition, sedimentation analysis for the January, March, May, July and September 2001 collections were conducted. For September/October 2001, mean (± 1 S.D.) stony coral density for the 23 sites was 2.62 ± 1.85 colonies/m2. Mean stony coral coverage was 2.39 ± 3.96%. Mean gorgonian density was 7.91 ± 8.01 colonies/m2 and mean sponge density was 14.09 ± 6.93 colonies/m2. First Reef sites had greater mean stony coral coverage but lower gorgonian and sponge density than Second and Third Reef sites. First Reef coral cover was much lower than the Third Reef when the First reef site, FTL4, was removed from the analysis. FTL4 had much greater stony coral cover than the mean cover for the remaining First Reef sites (19.95% compared to 1.45%). Shannon-Weaver Diversity Indices performed on the overall transect data resulted in values of 1.45 ± 0.53 and 1.72 ± 0.44 for cover and number of species respectively. Overall evenness was 0.77 ± 0.14 for number of species and 0.64 ± 0.21 for cover. There was no significant difference determined between the January/February 2001 site visit data and the September/October 2001 site visit data for mean stony coral density and cover. Mean octocoral density also did not differ significantly between these site visits, but mean sponge density was significantly less in September/October 2001 than in January/February 2001. Stony coral density, stony coral coverage, gorgonian density and sponge density data collected from the 18 monitoring sites established in 1997 and visited yearly from 1997 to 1999 were analyzed. No significant difference in yearly mean stony coral density, mean stony coral cover and mean gorgonian density was determined. Mean sponge density did show significant differences with 1998 sponge density greater than 1997. Trends in fish density were similar to those trends identified within the coral community transects. The greatest density of fishes occurs on the Third Reef followed by the First and Second. A difference in richness was seen amongst the three Reefs with the First Reef having the lowest number of species. The differences noted in abundance, density, and richness between the data collected in January/February 2001 and in September/October 2001 confirm previous reports of temporal differences in the fish assemblage offshore Broward County (Spieler 1998). The First Reef had a statistically higher rate of sedimentation than both the Second and Third Reefs when data from January-September 2001 were pooled. Pooled site data showed that January 2001 and May 2001 samples had the greatest sedimentation rates. The grain size for sites on the Third Reef was significantly smaller than both the First and Second Reefs. When site data were pooled, January 2001 had a significantly larger mean grain size than the other four sampling intervals in 2001. Data collected and analyses completed during this monitoring project will be used to help evaluate effects from the proposed beach renourishment project

    Marine Biological Monitoring in Broward County, Florida: Year 3 Annual Report

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    A study has been undertaken to monitor Broward County, Florida (southeast Florida) coral communities, reef fish assemblages and sedimentation rates in relation to possible effects from a proposed extensive beach renourishment (restoration) project. Coral communities and reef fish assemblages will be monitored at a total of 23 stations distributed offshore Broward County. This monitoring effort will characterize and quantify populations of scleractinian (stony) corals, octocorallian (gorgonian) corals, sponges, and reef fishes. In addition, sediment traps located at each station will be sampled and analyzed. This document reports the data collected during the third year of this project. Coral communities and fish assemblages were monitored at each of the 23 sites between September and October 2002. In addition, sedimentation analysis for the November 2001, January 200-, March 2002, May 2002, July 2002 and September 2002 collections are reported. For September/October 2002 (=Year 3), mean (± 1 S.D.) stony coral density for the 23 sites was 2.84 + 1.30 colonies/m2. Mean stony coral coverage was 2.16 ± 3.53%. Mean octocoral density was 8.93 ± 10.17 colonies/m2 and mean sponge density was 13.47 ± 5.90 colonies/m2. Although no significant difference was found between the three reef tracts for stony coral cover, stony coral density, and octocoral density, First Reef sites had greater mean stony coral coverage but lower octocoral density than Second and Third Reef sites. First Reef coral cover was much lower than the Third Reef when the First Reet site, FTL4, was removed from the analysis. FTL4 had much greater stony coral cover than the mean cover for the remaining First Reef sites (17.40% compared to 1.65%). Sponge density was significantly greater on the Third Reef sites than the First or Second Reef sites, which did not significantly differ. Shannon-Weaver Diversity Indices performed on the overall transect data resulted in values of 1.49 ± 0.48 and 1.71 ± 0.46 for cover and number of species respectively. Overall evenness was 0.67 ± 0.20 for number of species and 0.76 ± 0.14 for cover. Examining the 23 total sites, mean stony coral density has not significantly changed from the Year 1 (January/February 2001) Year 2 (September/October 2001) and Year 3 (September/October 2002) monitoring events. Mean stony coral cover at these 23 sites was found to be significantly greater in Year 2 than in Year 1 or 3, which did not significantly differ. At these 23 sites, mean octocoral density did not significantly differ between Years while mean sponge density was found to be significantly greater in Year 1 than in Year 2 or 3, which did not significantly differ. Stony coral density, stony coral coverage, octocoral density and sponge density data collected from the 18 monitoring sites established in 1997 and visited yearly from 1997 to 2002 were analyzed. There has been no significant difference in stony coral density from 1998 to 2002. The density of stony corals in 1997 was found to be significantly less than what was found in 1998 and 2002. Mean stony coral cover increased from 1997 to 2001 but decreased slightly in 2002. Statistically, stony coral cover did not differ from 1998 to 2002, but 1997 was found to have significantly less cover than in 2000 and 2001. The mean density of octocorals did not differ statistically between 1998 and 2002. Mean sponge density was found to be greatest in 1998 and has decrease each year with a low in density found in 2002. Statistically 1998 and 1999 had the greatest sponge density compared to 2001 and 2002, which had the lowest sponge density. The results of a multivariate statistical procedure indicate that the stony coral assemblages off Broward County have changed little from 1997 to 2002. This procedure has also shown that the stony coral assemblages on the Third and Second Reef sites have gieater similarity and that either have with most of the First Reef sites. Trends in fish density were similar to those trends identified within the coral community transects. The greatest density of fishes occurs on the Third Reef followed by the Second and First. A difference in richness was seen amongst the three Reefs with the First Reef having the lowest number of species. The differences noted in abundance, density, and richness between the data collected in January/February 2001 and in September/October 2001 and September/October 2002 confirm previous reports of temporal differences in the fish assemblage offshore Broward County (Spieler 1998). The First Reef had a statistically higher rate of sedimentation than both the Second and Third Reefs for the period from November 2001 to September 2002. The November 2001 samples had the greatest sedimentation rates. Sedimentation analysis indicates that the average grain size was significantly highest on First Reef sites, with Second and Third Reel sites lacking significant difference from one another. Average sediment rates for the three reefs since August 1997 indicate that the First Reef typically has the highest rate of sedimentation followed by the Second, then Third Reefs. Both sedimentation rate and average grain size from November 2001 to September 2002 appear to be consistent with data collected from previous years during these same sampling intervals. A comparison of sedimentation rate and wind speed revealed a similar pattern: when wind speed is low, sedimentation rates are low, and vise versa. This relationship is logical considering winddriven waves may cause sediment resuspension. Data collected and analyses completed during this monitoring project will be used to help evaluate effects from the proposed beach renourishment project

    The EBEX Experiment

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    EBEX is a balloon-borne polarimeter designed to measure the intensity and polarization of the cosmic microwave background radiation. The measurements would probe the inflationary epoch that took place shortly after the big bang and would significantly improve constraints on the values of several cosmological parameters. EBEX is unique in its broad frequency coverage and in its ability to provide critical information about the level of polarized Galactic foregrounds which will be necessary for all future CMB polarization experiments. EBEX consists of a 1.5 m Dragone-type telescope that provides a resolution of less than 8 arcminutes over four focal planes each of 4 degree diffraction limited field of view at frequencies up to 450 GHz. The experiment is designed to accommodate 330 transition edge bolometric detectors per focal plane, for a total of up to 1320 detectors. EBEX will operate with frequency bands centered at 150, 250, 350, and 450 GHz. Polarimetry is achieved with a rotating achromatic half-wave plate. EBEX is currently in the design and construction phase, and first light is scheduled for 2008.Comment: 13 pages, 10 figures. Figure 1 is changed from the one which appeared in the Proceedings of the SPI

    Guiding slow polar molecules with a charged wire

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    We demonstrate experimentally the guiding of cold and slow ND3 molecules along a thin charged wire over a distance of ~0.34 m through an entire molecular beam apparatus. Trajectory simulations confirm that both linear and quadratic high-field-seeking Stark states can be efficiently guided from the beam source up to the detector. A density enhancement up to a factor 7 is reached for decelerated beams with velocities ranging down to ~50 m/s generated by the rotating nozzle technique
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