Temperature and developmental plasticity during embryogenesis in the Atlantic cod<Emphasis Type="Italic"> Gadus morhua</Emphasis> L.

Atlantic cod (Gadus morhua L.) embryos were reared at 4 °C, 7 °C, and 10 °C, and the relative timing of developmental events was characterized, with particular reference to myotomal muscle. Embryos started to feed at an apparently equivalent stage of development, so comparisons were made between temperature groups on the basis of percentage of time to first feeding and somite stage. No differences were found in the time of hatching or timing of appearance of the otic placode, unpaired median fin fold, gut lumen, otic vesicle, lens of the eye, otoliths, first muscular contractions, swim bladder, and hindgut, or in the rate of development of somites, myotubes, myofibrils, and acetylcholinesterase activity over the temperature range studied. In contrast, closure of the blastopore occurred late with respect to segmentation at higher temperatures, at the 3-somite, 10-somite, and 12-somite stages at 4 °C, 7 °C, and 10 °C respectively. Muscle cellularity was also markedly altered in the 10 °C group relative to the 4 °C and 7 °C groups. Larvae reared at 10 °C had significantly more (+14%) deep white fibers at hatch (P <0.001), whereas numbers of superficial red fibers remained unchanged. It is suggested that differences in muscle cellularity might be related to changes in the relative timing of epiboly, through differential proliferation of presomitic myogenic cells and/or their relative exposure to inductive signals.     

Characterization of sewage sludge organic matter using solid-state carbon-13 nuclear magnetic resonance spectroscopy

Six sewage sludges from five sewage treatment plants in Australia were characterized using solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Spectra were acquired both before and after removal of mineral components through treatment with hydrofluoric acid (HF). Carbon mass balance indicated that little organic matter was lost on HF treatment, which significantly improved NMR sensitivity and spectral resolution, and decreased acquisition time and hence cost of NMR analysis. Two NMR techniques were used, the standard cross polarization (CP) technique and Bloch decay (BD). The BD technique had not been applied previously to the analysis of sewage sludge. For each sludge sample, both before and after HF treatment, the BD spectrum contained significantly more alkyl carbon. Spin counting, another technique applied to sewage sludge here for the first time, showed that the BD spectra of the HF-treated sludges were quantitative, while approximately 30% of the CP NMR signal went undetected. The discrepancy between CP and BD spectra was attributed to the presence of alkyl carbon with such high molecular mobility that the efficiency of cross polarization is affected. This study shows that sewage sludge organic matter is significantly different in chemistry to soil organic matter and has implications for the application of sewage sludge to agricultural land.     

Biodiversity Conservation and Resource Tenure Regimes: A Case Study from Northeast Cambodia

The management of tropical protected areas is a contentious issue in resource management and often leads to an unproductive polarization of viewpoints supporting either protectionist or sustainable development paradigms. This paper argues for a context-driven approach whereby effective management requires inputs from both paradigms in different situations. A key element of context is understanding long-practiced resource tenures and their ability to meet future conservation and livelihood goals. Different types of tenure arrangements are often required for different resources. This approach is illustrated by analysis of Virachey National Park in NE Cambodia. This park encompasses part of the ancestral territory of ethnic Brao people, who rely upon swidden agriculture, fish, terrestrial wildlife, and various nontimber forest products (NTFPs) for their livelihoods. These people have developed a mix of resource tenure regimes to promote sustainable use and to maximize local benefits. In the face of contemporary pressures, some of these traditional approaches are effective, while others are not. The paper suggests avenues for building on long-established management practices of the Brao to achieve park management goals while enhancing the welfare of the Brao people. A mix of private ownership, common property management, and central government involvement may be required to maximize benefits to local people and ensure long-term protection of biodiversity.     

Manganese-catalyzed degradation of phosphonic acids

The non-biodegradable and chemically very stable phosphonates are used in a variety of industrial applications including cooling waters, oil production and textile industry. We show here that they are degraded in the presence of Mn(II) and oxygen. The half-life for the reaction is 9 min near neutral pH. The presence of other cations such as Ca(II) and Zn(II) considerably slows down the reaction by competition with Mn(II) for the phosphonate. The reaction involves the oxidation of complexed Mn(II) by oxygen to Mn(III) and the subsequent oxidation of phosphonate by Mn(III) thus yielding two stable phosphonic acid breakdown products. The oxidation also proceeds in the presence of the mineral manganite (Mn(III)OOH), and yields the same breakdown products. The use of a newly developed chromatographic method revealed the presence of the breakdown products in wastewater. The results show that manganese-catalyzed oxidation might be an important pathway for phosphonate degradation in natural waters. Electronic Publication     

Global Supply of Biomass for Energy and Carbon Sequestration from Afforestation/Reforestation Activities

In this paper we provide an analytical framework to estimate the joint production of biomass and carbon sequestration from afforestation and reforestation activities. The analysis is based on geographical explicit information on a half-degree resolution. For each grid-cell the model estimates forest growth using a global vegetation model and chooses forest management rules. Land prices, cost of forest production and harvesting are determined as a function of grid specific site productivity, population density and estimates of economic wealth. The sensitivity of the results due to scenario storylines is assessed using different population and economic growth assumptions, which are consistent with B1 and A2 of the Intergovernmental Panel on Climate Change Special Report on Emission Scenarios (IPCC-SRES) marker scenarios. Considerable differences in the economic supply schedules are found. However, technical potentials seem to converge given constancy in other underlying assumptions of the model.     

Test of a behavior-based individual-based model: response of shorebird mortality to habitat loss.

In behavior-based individual-based models (IBMs), demographic functions are emergent properties of the model and are not built into the model structure itself, as is the case with the more widely used demography-based IBMs. Our behavior-based IBM represents the physiology and behavioral decision making of individual animals and, from that, predicts how many survive the winter nonbreeding season, an important component of fitness. This paper provides the first test of such a model by predicting the change in winter mortality of a charadriid shorebird following removal of intertidal feeding habitat, the main effect of which was to increase bird density. After adjusting one calibration parameter to the level required to replicate the observed mortality rate before habitat loss, the model predicted that mortality would increase by 3.65%, which compares well with the observed increase of 3.17%. The implication that mortality was density-dependent was confirmed by predicting mortality over a range of bird densities. Further simulations showed that the density dependence was due to an increase in both interference and depletion competition as bird density increased. Other simulations suggested that an additional area of mudflat, equivalent to only 10% of the area that had been lost, would be needed by way of mitigation to return mortality to its original level. Being situated at a high shore level with the flow of water in and out impeded by inlet pipes, the mitigating mudflat would be accessible to birds when all mudflats in the estuary were covered at high tide, thus providing the birds with extra feeding time and not just a small replacement mudflat. Apart from providing the first, and confidence-raising, test of a behavior-based IBM, the results suggest (1) that the chosen calibration procedure was effective; (2) that where no new fieldwork is required, and despite being parameter rich, a behavior-based IBM can be parameterized quickly (few weeks), and thus cheaply, because so many of the parameter values can be obtained from the literature and are embedded in the model; and (3) that behavior-based IBMs can be used to explore system behavior (e.g., the role of depletion competition and interference competition in density-dependent mortality).     

塔基图穆保护区——库克群岛的社区所属生态旅游明星

塔基图穆保护区 1996年创建于库克群岛的拉罗汤加岛 , 其目标是为了当前和未来生产者的利 益而对生物多样性实施保护 . 只有当地人民对其土地和资源拥有所有权 . 生态旅游将成为该 保护区的主要经济活动 . 在土地所有者同意和支持下 , 一个有指导的 " 大自然漫步 " 已经组 织起来 .     

Role of heavy polar organic compounds for water repellency of sandy soils

Separation and chemical characterisation of specific compounds responsible for soil water repellency has not previously been achieved. Here we describe the extraction, separation and analysis by gas chromatography-mass spectrometry of organic compounds found in wettable and water repellent sandy soils from the Netherlands and United Kingdom. Fatty acids (C₁₆–C₂₄), amides (C₁₄–C₂₄), alkanes (C₂₅–C₃₃), aldehydes/ketones (C₂₃–C₃₁) and complex ring-containing structures were detected in all samples. We found a greater abundance of high molecular mass polar compounds in the water repellent samples.