海南岛东海岸珊瑚礁生态系统中抗生素抗性基因的赋存特征

为了解海南岛近岸珊瑚礁生态系统中抗生素抗性基因（Antibiotic Resistance Genes,ARGs）的赋存特征,本研究借助绝对定量PCR技术分析了海南岛东海岸8个珊瑚礁礁区海水中的磺胺类（sul1、sul2）、喹诺酮类（qnrB、qnrS）和氯霉素类ARGs（cmlA1-01、cmlA1-02、cmx(A)）的丰度及其与海水盐度、营养盐（NH₃?-N、NO₂?-N、NO₃?-N、PO₄3?-P）和金属离子（Hg、As、Cu、Pb、Zn、Cd、Cr）浓度的相关性。结果发现,在8个调查站点海水中的磺胺类、喹诺酮类和氯霉素类共3类7种ARGs的检出率为100%,且sul2在所有调查站点中都是丰度最高的ARG（3.96×107～1.65×109 copies·L?1）。此外,5种ARGs[sul1、qnrS、cmlA1-01、cmlA1-02、cmx(A)]的丰度与盐度显著负相关,而qnrS和cmlA1-01的丰度均与NO₂?-N浓度显著正相关,sul1和qnrB的丰度分别与Cu和Cr浓度显著正相关。结果表明,海南岛东海岸珊瑚礁生态系统中存在多种类型的ARGs污染,盐度、营养盐和金属离子可能是驱动礁区ARGs传播的主要环境因素。     

Hybridization and the evolution of reef coral diversity

Hundreds of coral species coexist sympatrically on reefs, reproducing in mass-spawning events where hybridization appears common. In the Caribbean, DNA sequence data from all three sympatric Acropora corals show that mass spawning does not erode species barriers. Species A. cervicornis and A. palmata are distinct at two nuclear loci or share ancestral alleles. Morphotypes historically given the name Acropora prolifera are entirely F(1) hybrids of these two species, showing morphologies that depend on which species provides the egg for hybridization. Although selection limits the evolutionary potential of hybrids, F(1) individuals can reproduce asexually and form long-lived, potentially immortal hybrids with unique morphologies.     

Nitrogen fixation in a coral reef community

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.     

Solar ultraviolet radiation and coral reef epifauna

Many "shade-loving" reef organisms show adverse effects when irradiated with full natural sunlight but not if radiation shorter than 400 nanometers is screened out. Shortwave solar radiation appears to be an important physical factor controlling the biology of shallow tropical benthic marine communities.     

Net primary productivity in coral reef sponges

Nine of the ten most common sponge species on the fore-reef slope of Davies Reef(Great Barrier Reef) contain symbiotic cyanobacteria. Six of the ten are net primary producers, with three times more oxygen produced by photosynthesis than is consumed during respiration. Light interception is enhanced by morphological flattening, thereby increasing the potential for phototrophic nutrition, a factor crucial in the ecology of most sessile coral reef invertebrates.     

Recruitment and population dynamics of a coral reef fish

Daily otolith increments were used to determine the daily pattern of settlement of the bluehead wrasse (Thalassoma bifasciatum), a Caribbean coral reef fish. Recruitment occurs in brief and sporadic episodes even though bluehead wrasses spawn every day. Patterns of recruitment do not correspond to patterns of mortality on the reef. The composition of the adult population directly reflects the relative rates of recruitment of juveniles the year before. The population dynamics of this species may therefore be determined by the supply of recruits and not by the supply of space or some other resource on the reef.     

Acanthaster: effect on coral reef growth in panama

Analysis of data on coral abundance and growth, and the population size (26 individuals per hectare) and feeding rate of Acanthaster indicates that Pocillopora reefs on the Pacific coast of Panama are undergoing vigorous growth in the presence of this predator. Prediction of the effects of a population increase in Acanthaster to plague proportions (2.5 times that presently observed) suggests that reefs could still maintain a positive growth. However, Acanthaster at ten times the present population density would lead to rapid destruction of reefs. It is argued that coral destruction due to Acanthaster represents only one of several factors affecting coral reef progression.     

Preindustrial to modern interdecadal variability in coral reef pH

The oceans are becoming more acidic due to absorption of anthropogenic carbon dioxide from the atmosphere. The impact of ocean acidification on marine ecosystems is unclear, but it will likely depend on species adaptability and the rate of change of seawater pH relative to its natural variability. To constrain the natural variability in reef-water pH, we measured boron isotopic compositions in a approximately 300-year-old massive Porites coral from the southwestern Pacific. Large variations in pH are found over approximately 50-year cycles that covary with the Interdecadal Pacific Oscillation of ocean-atmosphere anomalies, suggesting that natural pH cycles can modulate the impact of ocean acidification on coral reef ecosystems.     

Reefs of the deep: the biology and geology of cold-water coral ecosystems

Coral reefs are generally associated with shallow tropical seas; however, recent deep-ocean exploration using advanced acoustics and submersibles has revealed unexpectedly widespread and diverse coral ecosystems in deep waters on continental shelves, slopes, seamounts, and ridge systems around the world. Advances reviewed here include the use of corals as paleoclimatic archives and their biogeological functioning, biodiversity, and biogeography. Threats to these fragile, long-lived, and rich ecosystems are mounting: The impacts of deep-water trawling are already widespread, and effects of ocean acidification are potentially devastating.     

Projecting coral reef futures under global warming and ocean acidification

Many physiological responses in present-day coral reefs to climate change are interpreted as consistent with the imminent disappearance of modern reefs globally because of annual mass bleaching events, carbonate dissolution, and insufficient time for substantial evolutionary responses. Emerging evidence for variability in the coral calcification response to acidification, geographical variation in bleaching susceptibility and recovery, responses to past climate change, and potential rates of adaptation to rapid warming supports an alternative scenario in which reef degradation occurs with greater temporal and spatial heterogeneity than current projections suggest. Reducing uncertainty in projecting coral reef futures requires improved understanding of past responses to rapid climate change; physiological responses to interacting factors, such as temperature, acidification, and nutrients; and the costs and constraints imposed by acclimation and adaptation.     

Local replenishment of coral reef fish populations in a marine reserve

The scale of larval dispersal of marine organisms is important for the design of networks of marine protected areas. We examined the fate of coral reef fish larvae produced at a small island reserve, using a mass-marking method based on maternal transmission of stable isotopes to offspring. Approximately 60% of settled juveniles were spawned at the island, for species with both short (<2 weeks) and long (>1 month) pelagic larval durations. If natal homing of larvae is a common life-history strategy, the appropriate spatial scales for the management and conservation of coral reefs are likely to be much smaller than previously assumed.