Spawning patterns in the leopard grouper, <Emphasis Type="Italic">Mycteroperca rosacea</Emphasis>, in comparison with other aggregating groupers

We documented the spawning patterns of the leopard grouper, Mycteroperca rosacea, from April to June 2005 in the central Gulf of California, Mexico to draw comparisons with other aggregate-spawning groupers and provide information useful for management of their fishery. Adults formed spawning aggregations of 150 to >700 individuals at specific sites, and spawning occurred daily at these sites from late April through early June. Courtship occurred throughout the day, but spawning was restricted to the evening hours. Adults spawned in groups of 6–40 fish, and pair-spawning was not observed. The group-spawning behavior of adults and the gonosomatic indices of mature males (maximum = 7.2%) suggest that sperm competition was present. The site-specificity of leopard grouper spawning aggregations and diel spawning period were typical of most aggregating groupers, and the size and structure of these aggregations was similar to other species in the genus Mycteroperca. Leopard grouper behavior patterns were unusual in that spawning aggregations persisted for extended periods, spawning was not synchronized with the lunar cycle, and adults aggregated during non-spawning periods. The extensive duration and site-specificity of spawning aggregations and the propensity of M. rosacea to form aggregations year-round increases the vulnerability of the species to overfishing. Policies that limit harvest from these aggregations are needed to improve the management of leopard grouper fisheries in the Gulf of California.     

载体对生物质油裂解镍基催化剂的性能影响

以改性处理的CaA分子筛、硅藻土和ZrO_2-CeO_2复合氧化物为载体,分别负载镍制备催化剂,并采用XRD、SEM、TPR、TG、FT-IR对催化剂的结构、形貌、表面酸中心种类、还原性能和积碳性能等进行了表征。结果表明,载体的种类影响催化剂性能,改性后的Ca A分子筛具有较大的比表面积和孔容,负载镍基催化剂表面具有较强的L酸和B酸中心,能与镍物种形成较强的相互作用,在生物质油催化裂解反应中表现出较好的活性,同时催化剂表面较强的酸中心也促进了积碳前驱物的形成;而Ni O/硅藻土催化剂和NiO/ZrO_2-CeO_2催化剂的酸中心强度相对较弱,影响了活性组分与载体的相互作用,活性组分在反应中烧结现象明显。     

某滑坡坝坝后稳定性分析

某滑坡坝位于某拟建水电站的上游,在国家级自然保护区内,是著名的旅游景点,其安全性对旅游开发、工程建设和下游居民生命财产安全影响很大,为了评价该滑坡坝的稳定性,需要对其发生洪水漫坝和渍坝的可能性进行研究,论证其安全性。通过计算的各种工况表明,滑坡坝坝后(坝体靠下游部分)是稳定的,对电站建设和下游居民不会产生威胁,滑坡坝是稳定的,可以进行综合开发。本文研究思路对类似工程有一定的借鉴意义。     

Variable impact of rice (Oryza sativa) on soil metal reduction and availability of pore water Fe2+ and Mn2+ throughout the growth period

Flooding of wetland or agricultural soils can result in substantial alteration of the pore water trace metal profiles and potentially also influence the bioavailability of other trace elements adsorbed to the insoluble oxides. Experimental microcosms were used to quantify the impact of rice (Oryza sativa) plants across an entire growing cycle on the concentrations of Mn²⁺ and Fe²⁺ in two soil types (red sodosol and grey vertosol). Two water management treatments were included: a standard flooded treatment and a saturated treatment (?3?kPa). Soil pore water profiles were established from samples collected at four sampling depths (2.5, 7.5, 15 and 25?cm) on 50 occasions. Fe²⁺ and Mn²⁺ concentrations were higher in flooded soil than in saturated soil and greatest at a depth of 7.5?cm. The presence of rice plants increased Mn²⁺ concentrations in flooded soils, but tended to decrease Mn²⁺ concentrations in saturated soils. The influence of rice plants on Fe²⁺ concentrations was greatest at a depth of 7.5?cm. Changes in soil pore water Fe²⁺ and Mn²⁺ concentrations due to the presence of rice plants were correlated with flowering and reproduction.     

Applying DPSIR to sustainable development

The DPSIR framework was devised in the late 1990s as a tool for the reporting and analysis of environmental problems, ranging in scale from global systems to localized watersheds. Since then, international organizations have begun to apply this framework to the evaluation of sustainable development initiatives, to better understand and overcome barriers to sustainability. While this may seem a logical application for an integrated environmental assessment tool, the use of DPSIR in sustainable development will likely perpetuate the least satisfactory outcomes of development. DPSIR cannot address the impact of aggregated, informal responses on the drivers and pressures related to environmental problems and sustainability challenges. This problem is not merely an oversight of the framework, but an issue that emerges within the structure of DPSIR itself through the unexamined, unacknowledged hierarchy of actors that this framework implicitly creates with its typology. Therefore, a DPSIR-centered approach is not a new direction for development within international organizations, but instead, a reproduction of existing inequalities between actors and stakeholders within current approaches.     

Towards improved socio-economic assessments of ocean acidification’s impacts

Ocean acidification is increasingly recognized as a component of global change that could have a wide range of impacts on marine organisms, the ecosystems they live in, and the goods and services they provide humankind. Assessment of these potential socio-economic impacts requires integrated efforts between biologists, chemists, oceanographers, economists and social scientists. But because ocean acidification is a new research area, significant knowledge gaps are preventing economists from estimating its welfare impacts. For instance, economic data on the impact of ocean acidification on significant markets such as fisheries, aquaculture and tourism are very limited (if not non-existent), and non-market valuation studies on this topic are not yet available. Our paper summarizes the current understanding of future OA impacts and sets out what further information is required for economists to assess socio-economic impacts of ocean acidification. Our aim is to provide clear directions for multidisciplinary collaborative research.     

Habitat preferences of coral-associated fishes are altered by short-term exposure to elevated CO2

Rising atmospheric carbon dioxide (CO₂) concentrations are causing additional CO₂ to be absorbed by the oceans. Recent studies show that exposure to elevated CO₂ causes olfactory impairment in reef fishes; however, the ecological consequences of this impairment are largely unknown. This study examined the effects of short-term exposure to elevated CO₂ on habitat preferences of coral-dwelling gobies. Adult gobies collected from the reef at Lizard Island (Great Barrier Reef, Australia) were exposed for 4 days to ambient CO₂ (440 μatm) or elevated CO₂ (880 μatm). Habitat preferences were then tested in laboratory and field experiments at ambient conditions. In olfactory preference tests, Paragobiodon xanthosomus displayed a strong preference for odour cues of their sole host coral Seriatopora hystrix; however, this preference was absent in gobies exposed to elevated CO₂. Habitat choice experiments conducted in the field showed that Gobiodon histrio placed on dead coral colonies located preferred live habitat within 24 h; however, gobies exposed to elevated CO₂ associated with both preferred and non-preferred habitats in approximately equal frequency. Preferred habitats are known to confer fitness advantages to coral-dwelling gobies. Consequently, these results suggest that future elevated CO₂ levels might affect the ability of habitat specialist fishes to select favourable habitats.