نتایج جستجو برای: coral limestone
تعداد نتایج: 21765 فیلتر نتایج به سال:
Over 60% of Singapore’s coral reef habitat have been lost to decades of urban development pressure including land reclamation. Underwater visibility of less than 2m due to heavy sedimentation has restricted the healthy coral growth zone to the reef crest and upper 5m of the reef slope. Despite the impacts, coral species diversity has remained high together with predictable coral mass spawning e...
Coral reef ecosystems worldwide are under pressure from chronic and acute stressors that threaten their continued existence. Most obvious among changes to reefs is loss of hard coral cover, but a precise multi-scale estimate of coral cover dynamics for the Great Barrier Reef (GBR) is currently lacking. Monitoring data collected annually from fixed sites at 47 reefs across 1300 km of the GBR ind...
Developing functional concrete mixtures with less ordinary portland cement (OPC) has been one of the key objectives of the 21st century sustainability movement. While the supplies of many alternatives to OPC (such as fly ash or slag) may be limited, those of limestone and silica powders produced by crushing rocks seem virtually endless. The present study examines the chemical and physical influ...
Replacement dolomite in the Latemar carbonate buildup developed when limestone was infiltrated by reactive fluid. Minor-element, trace-element, and oxygen and carbon isotope compositions of dolomite and precursor limestone constrain the origin of the fluid and fundamental aspects of the flow. Inferred salinity (similar to seawater); temperature (45°–85°C); Sr/Sr (0.7076–0.7079); Ca/Mg (<1.4); a...
An experiment was conducted to evaluate the influence of different Ca sources (limestone, Ca chloride, and Lipocal, a fat-encapsulated tricalcium phosphate, TCP) in conjunction with 4 dietary levels of non-phytate P (NPP) on performance, ileal digestibility of Ca and P, and bone mineralization in broiler chickens. Calcium sources were also evaluated in vitro to measure acid-binding capacity (AB...
Coral communities are changing rapidly worldwide through loss of coral cover and shifts in species composition. Although many reef-building corals are likely to decline, some weedy opportunistic species might increase in abundance. Here we explore whether the reshuffling of species can maintain ecosystem integrity and functioning. Using four common Caribbean reef-building coral genera we modele...
Corals were bleached throughout Kenya and most of the western Indian Ocean in the warm season of 1998 and coral mortality occurred over an extended period from March to July 1998 (1–3). Nearly all studied Kenyan coral reefs had coral cover of around 10% after the coral bleaching (1, 3). The greatest levels of mortality were experienced in marine protected areas that originally had high coral co...
More diverse communities are thought to be more stable-the diversity-stability hypothesis-due to increased resistance to and recovery from disturbances. For example, high diversity can make the presence of resilient or fast growing species and key facilitations among species more likely. How natural, geographic biodiversity patterns and changes in biodiversity due to human activities mediate co...
BACKGROUND A number of factors have recently caused mass coral mortality events in all of the world's tropical oceans. However, little is known about the timing, rate or spatial variability of the loss of reef-building corals, especially in the Indo-Pacific, which contains 75% of the world's coral reefs. METHODOLOGY/PRINCIPLE FINDINGS We compiled and analyzed a coral cover database of 6001 qu...
One of the most diverse vertebrate communities is found on tropical coral reefs. Coral-reef fishes are not only remarkable in color and shape, but also in several aspects of physiological performance. Early in life, at the end of the pelagic larval stage, coral-reef fishes are the fastest swimmers of all fishes in relation to body size, and show the highest specific rates of maximum oxygen upta...
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