The role of benthic macrophytes and their associated macroinvertebrate community in coastal lagoon resistance to eutrophication

Eutrophication is widely recognised as one of the major menaces to coastal environments, particularly enclosed bays and lagoons. Although there is a general understanding of the consequences of eutrophication in these systems, there is a lack of sufficient knowledge concerning biotic feedbacks that influence eutrophication patterns and the resistance capacity of coastal environments.In this paper, the isotope ratios of main producers and consumers of a Mediterranean lagoon were examined in order to elucidate the fate of anthropogenic inputs from the main watercourse flowing into the lagoon.The results of the study of stable isotope data in the Mar Menor lagoon reflected that the whole benthic community plays an important role as a natural ‘filter’ that removes excess nutrients from the water column and stores them in the sediments, thereby enhancing lagoon resistance to eutrophication.     

Decline of the Jakarta Bay molluscan fauna linked to human impact

In 1937/38 representative mollusc collections were made in Jakarta Bay (West Java, Indonesia). New data from here and the adjacent offshore Thousand Islands archipelago (Kepulauan Seribu) became available in 2005. Although collecting efforts and sampling methods differed, a comparison of the molluscan fauna of Jakarta Bay between 1937/38 and 2005 reveals a distinct deterioration. From 1937 to 2005, Jakarta Bay received increasing amounts of sewage from the greater Jakarta area, as well as increased sediment input from the deforested West Java hinterland. Predatory gastropods and numerous mollusc species associated with carbonate (reef) substrate have vanished from Jakarta Bay, among which many edible species.     

海南东部沿岸河流和潟湖中溶存甲烷的分布及通量

甲烷(CH4)作为大气中重要的温室气体,直接或间接地影响全球气候变化。于2009年3月27日至4月15日对海南东部河流(文昌河、文教河、万泉河)、潟湖(八门湾、博鳌、小海和老爷海)等进行了调查,采集了表层和部分底层水样,对溶解CH4浓度进行了测定并初步估算了其水-气交换通量。结果表明,文昌河、文教河受人为活动影响较大,表层CH4饱和度较高,分别为(60664±25118)%、(38582±26339)%,污水输入、红树林输入和现场产生是其CH4的主要来源。万泉河表层CH4饱和度为(9472±5594)%,现场产生是其水体溶存CH4的主要源。八门湾、博鳌、小海和老爷海潟湖表层水体溶存CH4均处于过饱和状态,但其饱和度远小于入湖河流,分别为(2471±2937)%、(5692±3435)%、(546±251)%和(6878±4635)%,其中河流输入、地下水和红树林间隙水输入、现场产生是潟湖中CH4的主要来源,水体中CH4的氧化和水-气交换是潟湖中CH4的主要汇。初步估算出文昌河和万泉河CH4的水-气交换通量分别为5967.0±5142.1和496.2±335.9μmol·m 2·d 1,八门湾、博鳌、小海和老爷海潟湖的水-气交换通量分别为528.7±625.0、441.7±473.3、26.6±21.6和1287.8±1453.3μmol·m 2·d 1。海南东部河流、潟湖是近岸水体及大气CH4的净源。     

Responses and adaptation strategies of commercial and charter fishers to zoning changes in the Great Barrier Reef Marine Park

Fishers' responses to changes in resource access through the imposition of marine protected areas can be a critical factor influencing the likelihood of achieving management objectives.Face-to-face interviews with 114 commercial and charter fishers were conducted to investigate their responses and adaptation strategies to the increase in the size and number of no-take zones imposed by the 2004 Great Barrier Reef Marine Park zoning plan. Despite holding positive attitudes towards marine biodiversity protection, fishers were generally unsupportive of the new zoning plan 5 years after its implementation. Fishers' lack of support was related to the perception that they had not been adequately engaged in the rezoning process and the perception of significant impacts of the zoning plan on fishing businesses. Fishers generally believed that the new zoning plan had a negative impact on their access to productive fishing areas, the numbers of fish they catch, the profitability of their fishing business, and their personal income. In response to the new no-take zones, fishers tended to redistribute their fishing activity to locations closer to their home port, and to locations already known to them through their previous fishing, resulting in an increase in high density fishing locations within the park. Despite the impacts that fishers experienced, most reported that they have adapted their fishing activity and fishing business at least moderately well to the new zoning plan, suggesting that many of the impacts experienced by fishers might be short-term and may decline over time as fishers learn to adapt to the new zoning system. The information provided should prove valuable as a baseline for continued monitoring of the costs and benefits of the Great Barrier Reef Marine Park rezoning into the future.     

Daily availability of nutrients and metals in a eutrophic meso-tidal coastal lagoon (Óbidos lagoon, Portugal)

This baseline reports daily variations of physico-chemical parameters, nutrients and metals in water of two sites [eutrophic conditions (BB) versus reference (LL)] in Óbidos coastal lagoon (Portugal). Dissolved oxygen in BB varied between 40% saturation levels (night) and 190% (daylight). , and ratios to Al of Mn, Fe and Pb in suspended particulate matter increased during the period of lower oxygenation, indicating exportation of nutrients and metals from the sediment to water at night. At LL, O₂ values oscillated always around 100%. and Mn/Al ratio at LL were always lower than at BB and no increases were found during the night. The input of and Mn provided from the sediment at BB during the night could surpass the contribution of freshwater discharges. PCA confirmed the separation of most samples from BB and LL. These results pointed to the importance of assessing chemical conditions over day-night cycles.     

基于Reef Check调查的涠洲岛珊瑚礁生态状况评价

采用Reef Check（珊瑚礁健康调查法）和珊瑚礁生态系统健康指标因素分析法,对广西北海涠洲岛珊瑚礁健康状况进行评价。Reef Check调查从2001―2012年共进行了11 a,调查区为涠洲岛的竹蔗簝、公山、牛背坑3个地点,调查项目包括鱼类、无脊椎动物、珊瑚礁底质。调查结果表明：涠洲岛周边不同区域的珊瑚礁生态状况有较大差异,在竹蔗簝和牛背坑调查区的珊瑚礁覆盖率较为稳定;而在公山调查区,则发现珊瑚在2002年间出现了大面积死亡的情况,至今尚未恢复。利用珊瑚礁生态系统健康指标因素分析法对涠洲岛珊瑚礁健康状况进行评价,结果表明：竹蔗簝和牛背坑的珊瑚礁健康状态相似,都属于一般,其中牛背坑略好,而公山的珊瑚礁健康状态较差。     

Enhancement of regional variations in salinity and temperature in a coral reef lagoon, New Caledonia

The variability in salinity and temperature in the southwest lagoon of New Caledonia (2100 km²) under non-storm conditions is analysed using a 4-year dataset (1997–2001). Seasonal and interannual variations in salinity are amplified nearshore. Temperature is larger in bays than in the open lagoon during summer, the reverse is true in winter. El Niño Southern Oscillation (ENSO) related nearshore temperature variations parallel those at regional scale, but with seasonal variations amplified. Haline stratification, if any, is enhanced in coastal areas. To cite this article: S. Ouillon et al., C. R. Geoscience 337 (2005).     

Geochemical evaluation of the Lagos lagoon sediments

Lagos lagoon is underlain by the Tertiary to recent coastal plain sands of the Dahomey Basin and receives a huge volume of sediments from surface runoffs, canals, rivers and other drainage networks. The dumping of domestic and industrial wastes into these drainage channels open up the possibility of deleterious materials, which carry with them toxic metallic ions, being discharged as wastes into the channels, these eventually find their ways into the lagoon. Sediments being sinks for metals, the identification and quantitative evaluation of metallic ions in the Lagos lagoon sediments is desirable. This study aimed at ascertaining the concentrations of these metallic ions in the sediments. One hundred samples of sediment were systematically obtained along the banks, drainage channels （waste discharge points）, shelves and the center of the lagoon. These samples were dried, disaggregated and sieved for grain size （granulometric） analysis to evaluate the transport and depositional mechanism; X-ray diffraction and heavy mineral separation were used to determine the mineralogy. The 〈75 μm sieved portions of the samples were digested using aqua regia at 96℃ for two hours. The resulting clear solutions were analyzed for major oxides and trace metals using the Inductively Coupled Plasma-Optical Emission Spectrometry （ICP-OES）. X-ray diffraction analysis revealed quartz as the preponderant mineral. The geochemical result revealed that SiO2 ranges from 78.57%-98.88%; TiO2, 0.01%-0.32%; A1203, 0.15%-6.32%; Fe2O3, 0.44%-11.62%; K2O, 0.10%-9.60%; CaO, 0.04%-5.50%; MgO, 0.04%-0.98% and P2O5, 0.01%-0.30%, The major oxide compositions indicate the dominance of sand particles over clay in the sediments.