Holocene reef growth in Torres Strait

The platform and fringing reefs of Torres Strait are morphologically similar to reefs of the northern Great Barrier Reef to the south, except that several are elongated in the direction of the strong tidal currents between the Coral Sea and the Gulf of Carpentaria. Surface and subsurface investigations and radiocarbon dating on Yam, Warraber and Hammond Islands reveal that the initiation and mode of Holocene reef growth reflect antecedent topography and sea-level history. On the granitic Yam Island, fringing reefs have established in some places over a Pleistocene limestone at about 6 m depth around 7000 years BP. Emergent Holocene microatolls of Porites sp. indicate that the reefs have prograded seawards while sea level has fallen gradually from at least 0.8 m above present about 5800 years BP. On the Warraber Island reef platform drilling near the centre indicated a Pleistocene limestone foundation at a depth of about 6 m over which reefs established around 6700 years BP. Reef growth lagged behind that on Yam Island. Microatolls on the mature reef flat indicate that the reef reached sea level around 5300 years BP when the sea was around 0.8–1.0 m above present. On the reef flat on the western side of Hammond Island bedrock was encountered at 7–8 m depth, overlain by terrigenous mud. A progradational reef sequence of only 1–2 m thickness has built seaward over these muds, as sea level has fallen over the past 5800 years. Reef-flat progradation on these reefs is interpreted to have occurred by a series of stepwise buildouts marked by lines of microatolls parallel to the reef crest, marking individual coalescing coral heads. Detrital infill has occurred between these. This pattern of reef progradation is consistent with the radiocarbon dating results from these reefs, and with seismic investigations on the Torres Reefs.     

Inorganic nitrogen in coral reef sediments

Representative profiles of inorganic nitrogenous species dissolved in interstitial waters of coral reef sands are presented. Ammonium is the dominant nitrogenous species in these pore waters with concentrations of up to 40 μm. Nitrate is present but in lower concentrations. Nitrite is found only occasionally in trace amounts. Computations of diffusive fluxes and inferences concerning microbial activity are derived from the profile structures. Computed flux rates of nitrogenous species from the sediment to the water column range between 0.75 and 1.37 μM m⁻¹ h⁻¹. These inputs may represent a significant source of recycled nitrogen to the primary producers of the coral reef ecosystem.     

Coral reef restoration projects in Thailand

The degradation and deterioration of coral reefs in Thailand has continued for several decades due to pressures from fishery and tourism activities and, more recently, from bleaching. Several institutions and organizations, from both the government and the private sector, have been involved in programs to restore degraded coral reefs. The objectives, scales and methods of these restoration projects have varied widely. This paper briefly reviews the achievements of selected coral reef restoration projects and provides guidelines for future restoration initiatives. The high cost and limited scale of restoration projects puts the onus on governments and communities to prevent damage to coral reefs in the first place. Where restoration is necessary, basic data on the biology and ecology of target species of corals, socio-economic analyses and the involvement of local communities in all stages of the project are key elements for success.     

Scleractinian settlement patterns to natural cleared reef substrata and artificial settlement panels on an Indonesian coral reef

Recruitment is a key factor driving the population dynamics of scleractinian corals, but despite its importance, we still have a poor understanding of recruitment processes in the Coral triangle region, which contains the most biodiverse marine ecosystems in the world. This study aimed to compare settlement rates to artificial settlement panels with cleared areas of natural reef in order to assess whether panels are a suitable indicator of natural coral settlement rates. We recorded coral settlement rates to panels made of two different materials (concrete and terracotta), attached to the reef at two different orientations (vertical and horizontal), and compared these settlement rates to those on cleared areas of natural reef positioned on vertical reef walls, over a 12 month period. We examined settlement rates at four sites in the Wakatobi National Marine Park, south-east Sulawesi, Indonesia; two reefs were light-limited, highly sedimented sites with low coral cover (<10%) and two had moderate coral cover (approx. 40%) and lower sedimentation rates. Panels were directly attached to the reef at 6–7 m depth. The number of coral spat per tile ranged from 0 to 34 and no significant differences were reported between the settlement rates to cleared natural reef areas and settlement panels. Significantly higher numbers of spat settled on the cryptic (back) side of the panels, while no significant difference was found between settlement rates to the different panel materials, or between the different orientations or any combination of these two factors. There is, however, a significant difference in the settlement rates between sites, for both settlement panels and permanent cleared areas, with higher settlement rates at the sites with higher live coral cover. We conclude that both concrete and terracotta panels yield similar settlement rates, and orientation makes no difference to settlement rates when panels are directly attached to the reef. Our results demonstrate that artificial substrata provide comparable settlement rate data to natural substrata and therefore are suitable for monitoring coral settlement rates in the future.     

Coral reef metrics and habitat equivalency analysis

When coral reefs held in United States public trust are injured by incidents such as vessel groundings or oil spills, a natural resource damage assessment (NRDA) process may be conducted to quantify the resource service loss. Coral cover has been used as an indicator metric to represent lost services in habitat equivalency analyses for determination of compensatory restoration. Depending on the injury and habitat, however, lost services may be more comprehensively represented by alternative approaches such as composite metrics which incorporate other coral reef community characteristics, or a resource-scale approach utilizing size-frequency distributions of injured organisms. We describe the evolving state of practice for capturing coral reef ecosystem services within the natural resources damage assessment context, explore applications and limitations of current metrics, and suggest future directions that may increase the likelihood that NRDA metrics more fully address ecosystem services affected by an injury.     

The health and future of coral reef systems

Coral reefs are among the most productive and diverse ecosystems on earth and provide a multitude of valuable ecosystem services. Moreover, the resources derived from coral reefs are essential to the food security of millions of people living within tropical coastal communities. Unfortunately, burgeoning human populations in coastal regions are placing an unsustainable burden on these resources such that degradation of coral reefs is common. In addition, during 1998, El Niño driven increases in sea temperature caused a mass bleaching event that further degraded many of the world's coral reefs. This article provides a brief review of the status of the world's coral reefs and highlights their value to society. Also, the anthropogenic and natural disturbances that threaten the future of coral reefs are discussed and finally, this article offers some potential remedies that promote sustainable use of coral reef resources thus ensuring their future survival.     

Spatial considerations when monitoring reef fishes

Spatial dependence can obscure relationships between response and explanatory variables because of structuring within the residuals reducing variance and biasing coefficient estimates. Here, we highlight the influence of the spatial component, in the presence of spatial dependence, on abundance trends. This is illustrated using abundance data for a Critically Endangered reef fish, dageraad Chrysoblephus cristiceps, which were obtained from a long-term monitoring programme in the Tsitsikamma National Park marine protected area, South Africa. Correlograms illustrate distinct spatial structuring in the abundance data, and spatial variables were determined as more important than temporal variables when ranked according to predictive power using a random forest analysis. A generalised additive model (GAM) that did not account for spatial dependencies was compared to a generalised additive mixed model (GAMM) that incorporated a spatial residual correlation structure. Results derived from the spatially explicit GAMM differed considerably from the GAM lacking a spatial component, with the latter deemed to produce over-precise and partially biased abundance trends. The study emphasises the importance of space in accurately modelling abundance estimates, particularly temporal trends, and provides an introduction to the minimal statistical requirements necessary to address the violations associated with spatial autocorrelation.     

徐闻珊瑚礁资源的保护、恢复和开发

珊瑚礁因其形成构造独特，造型各异，加上美丽的沙滩，成为不可多得的旅游资源。本文以中国广东省雷州半岛徐闻县珊瑚礁为例，分析了珊瑚礁的形成、生长环境和影响因素，认为珊瑚礁作为一种宝贵的资源，应在保护和恢复的基础上合理的开发利用，以适应旅游开发的需要。     

SCUBA divers above the waterline: Using participatory mapping of coral reef conditions to inform reef management

Coral reefs provide important ecological services such as biodiversity, climate regulation, and cultural benefits through recreation and tourism. However, many of the world's reefs are declining, with Caribbean reefs suffering a significant decline in living corals over the past half century. This situation emphasizes the need to assess and monitor reef conditions using a variety of methods. In this study, a new method for assessing reef conditions to inform management using participatory mapping by coral reef “experts” in the U.S. Virgin Islands (USVI) is described. Occupational SCUBA divers were recruited (n=87) to map coral reef conditions, uses, and threats (stressors) using an internet-based mapping website. The data reveal an uneven geographic distribution of reef conditions in the USVI with the most frequently mapped perceived healthy reef characteristics being: large amount of physical reef structure (n=872 markers); endangered or threatened species present (n=721); and large amount of live coral cover (n=615). The greatest perceived threats were: invasive species (n=606); water pollution (n=234); and unsustainable fishing (n=200). Areas of important reef characteristics, perceived threats to reefs, and perceived recovery potential were plotted to identify areas requiring critical management attention. The authors found that perceptions of healthy reef conditions outnumbered perceptions of reef threats for nine of the ten most familiar coral reefs; the most frequent activity type within the coral reefs was tourism diving; and for the most familiar coral reefs, the divers perceived a high recovery potential. Given the novelty of participatory mapping methods to assess coral reefs, the strengths and weaknesses of the method is evaluated. The authors further propose a management typology for categorizing reef areas to inform their future management. In the absence of primary data, or, as a supplement to underwater surveys and remotely-sensed data on reef condition, participatory mapping can provide a cost-effective means for assessing coral reef conditions while identifying place-specific reef locations requiring management attention.     

沉积物对珊瑚礁及礁区生物的影响

海水中日益增多的悬浮物和泥沙沉降是导致珊瑚礁严重衰退的原因之一。沉积物覆盖在珊瑚礁生物表面,影响其呼吸作用,而海水浊度的增加会减少光合作用的可利用光。过多的沉积物改变了礁区的物理以及生物过程,从而对珊瑚礁生态系的结构和功能产生不利影响。为了有效评估珊瑚礁的变化趋势,如优势种丰度以及空间分布的变化等,应用标准的监测方法进行长期监测对于掌握这一复杂生态系统的变化是非常关键的。综述了沉积物对珊瑚生长率、生长形态、代谢和繁殖与补充以及礁区生物的影响,并指出未来的研究方向,以期为珊瑚礁的保护提供参考。     

涠洲岛珊瑚礁生态恢复可行性评估及其恢复策略

广西涠洲岛地处世界珊瑚礁分布的北缘,其造礁石珊瑚具有较高的生态价值和科学研究价值,然而近30年来涠洲岛的造礁石珊瑚资源呈逐年下降趋势,正面临生物多样性衰退和生态服务功能下降的威胁。本研究针对涠洲岛珊瑚礁生态衰退区域,参照珊瑚礁生态恢复潜力评估决策流程进行恢复可行性评估和恢复策略探讨。结果显示,该区域有造礁石珊瑚5科10属21种;表征海水水质质量的6项指标均在I类水质标准范围,且常年处于贫营养化;大型海藻覆盖率不足1.00%,90.00%以上的珊瑚礁鱼类为杂食性,且该鱼类种群结构有利于调控大型海藻的暴发性生长,与大型藻类和浮游动植物的多样性相适应,适宜珊瑚生长。但该区域造礁石珊瑚平均覆盖率仅有5.60%,底质类型57.27%为礁石,34.30%的底质为非稳定的碎石和砂,珊瑚幼体补充量平均为3.17 ind/m²,珊瑚幼体更新缓慢。以上结果表明,涠洲岛珊瑚礁具有一定的自然恢复潜力,但珊瑚覆盖率低、幼体补充量少以及部分底质结构不稳定是限制涠洲岛珊瑚礁自然恢复的主要因素,需要加强人工干预。在减少人类活动干扰的前提下,适时进行园艺式培育珊瑚苗种、批量珊瑚原位种植和构建人工珊...     

Seasonal and ontogenetic patterns of habitat use in coral reef fish juveniles

We investigated the diversity of patterns of habitat use by juveniles of coral reef fishes according to seasons and at two spatial scales (10–100 m and 1–10 km). We conducted underwater visual censuses in New Caledonia's Lagoon between 1986 and 2001. Co-inertia analyses highlighted the importance of mid-shelf habitats at large spatial scale (1–10 km) and of sandy and vegetated habitats at small spatial scale (10–100 m) for most juveniles. Among all juvenile species, 53% used different habitats across seasons (e.g. Lutjanus fulviflamma and Siganus argenteus) and 39% used different habitats as they grow (e.g. Lethrinus atkinsoni and Scarus ghobban). During their ontogeny, at large and small scales, respectively, 21% and 33% of the species studied showed an increase in the number of habitats used (e.g. L. fulviflamma, L. atkinsoni), 10% and 3% showed a decrease in the number of habitats used (e.g. Amphiprion melanopus, Siganus fuscescens), 23% and 3% showed a drastic change of habitat used (e.g. S. ghobban, Scarus sp.) whereas 46% and 61% showed no change of habitat used (e.g. Lethrinus genivittatus, Ctenochaetus striatus). Changes in habitat use at both small and large spatial scales occurred during the ontogeny of several species (e.g. S. ghobban, Scarus sp.). Results pointed out the different spatial and temporal scales of juvenile habitat use to account for in conservation decisions regarding both assemblage and species-specific levels.     

海南珊瑚礁的现状与保护对策

海南是我国最大的海洋省,位于我国的最南端,北纬3°58'～20°10',东经108°37'～117°50',总面积150万km2余,其中将近98%是海洋,陆地主要是海南岛,总面积约3.39万km2,环岛海岸线长达1 528km,为热带气候。海南省沿岸一些浅海水域及南海诸岛十分适合珊瑚生存和珊瑚礁生成,曾母暗沙等就是珊瑚礁岛,极大地丰富了海南的生物多样性,对沿海地区发展和环境保护提供了有力的支持。一、珊瑚礁概况珊瑚是地球上最古老的海洋生物,现在的珊瑚都是古珊瑚的后代,在动物分类学上属于腔肠动物门珊瑚虫纲。珊瑚礁是自然界最令人赞叹的景观之一,无数的礁岩生物…     

人工藻礁设计与投放的研究进展

人工藻礁就是人为设置在水域中,为海洋藻类提供生长繁殖场所,从而吸引鱼虾贝类等水生动物到藻场来索饵繁育,以达到优化海底环境,保护、增殖渔业资源和提高渔获物质量为目的的构造物,是一种恢     

The influence of reef type and seasonality on population structure of coral‐reef fishes within Malindi Marine Park,Kenya

Effective conservation requires knowledge of the effects of habitat on distribution and abundance of organisms. Although the structure of coral reef fish assemblages is strongly correlated with attributes of reef structure, data relating reef types to fish assemblages are scarce. In this study we describe the influence of gross habitat characteristics and seasonality on coral reef fish assemblages of fringing and patch reefs in Kenya. Results showed that total fish abundance was not significantly different between the reefs; however, the fringing reef had higher species diversity during both the northeast (42 spp.) and southeast (36 spp.) monsoon seasons when compared to the patch reef. The more fished species (e.g. Siganus sutor and Lethrinus mahsena) were more abundant on the patch reef in both seasons. Statistical analysis indicated common species between the reefs were more abundant on the fringing reef. Seasons affected abundance of the more vagile species (S. sutor), whereas the reef‐attached sky emperor, L. mahsena was affected more by reef type than by seasons. No significant interaction effects of habitat and seasons were found, indicating independence of habitat and environmental variability in affecting fish assemblages on the reefs. Smaller sized fish dominated the fringing reef more than the patch reef, whereas the skewness index (Sk) indicated a normal‐sized frequency distribution on the patch reef. Trophic structure of the fishes varied more within than between reefs, whereas fish assemblage structure was affected more by seasons on the fringing reef. These results suggest that conservation measures such as marine protected area (MPA) design and setting should consider effects of reef morphology and environmental variability on coral‐reef fish assemblage structure.     

礁坪上波浪传播的数值模拟

本文基于具备间断捕捉能力的二阶全非线性Boussinesq数值模型,对规则波和随机波在礁坪地形上的传播变形进行了数值模拟。该模型采用高阶有限体积法和有限差分方法求解守恒格式的控制方程,将波浪破碎视为间断,同时采用静态重构技术处理了海岸动边界问题。重点针对礁坪上波浪传播过程中的波高空间分布和沿程衰减,礁坪上的平均水位变化,以及波浪能量频谱的移动和空间差异等典型水动力现象开展数值计算。将数值结果与实验结果对比,两者吻合情况良好,验证了模型具有良好的稳定性,具备模拟破碎波浪和海-岸动边界的能力,能较为准确地模拟波浪在礁坪地形上的传播过程中发生的各种水动力现象。     

The physiological response of the reef coral Pocillopora damicornis to elevated temperature: results from coral reef mesocosm experiments in Southern Taiwan

Given the threat of climate change towards scleractinian corals, there is an urgent need to understand their physiological mechanisms of acclimation to increasing temperatures. To gain insight into this process, two mesocosm-based experiments were conducted in Southern Taiwan with the model reef-building coral Pocillopora damicornis. In the first study, temperature was gradually elevated to 32 °C, though reduced to ambient levels at night, in order to simulate a temperature profile that can characterize intertidal reefs of Southern Taiwan. All corals acclimated to such conditions over the course of the month-long experiment, as evidenced by a variety of physiological and sub-cellular responses. In the second experiment, corals were exposed continually to 31.5 °C for two weeks, and, in contrast to results from the first study, the majority of the corals died, revealing that prolonged exposure to this temperature is lethal for this dominant reef builder of many regions of the Pacific Ocean.