Greenhouse gas buildup, sardines, submarine eruptions and the possibility of abrupt degradation of intense marine upwelling ecosystems

Widespread hypoxia and massive eruptions of noxious, radiatively active gases currently characterize the world's strongest eastern ocean upwelling zone. Theory, modelling results and observations suggest that the world's coastal upwelling zones will undergo progressive intensification in response to greenhouse gas buildup. This presents the prospect of progressive development of similarly degraded marine ecosystems in additional regions and of a contributing feedback loop involving associated additions to the global buildup rate of greenhouse gases, resulting further increases in upwelling intensity, creation of additional sources of greenhouse gas emissions, and so on. Abundant sardine stocks might be a mitigating factor opposing the process.     

不同照度对棉铃虫蛾活动的影响

棉铃虫蛾分别在五个日龄（第二至第六天）,各经过五个光照梯度的光照处理,结果表明,10－1～10－3lX照度范围是棉铃虫蛾比较合适的活动范围,计算同时表明,棉铃虫蛾在不同照度下的活动反应量差异显著,尤以在10-3lX照度下的活动反应量为最大,约88％左右。     

Structural diversity indices based on airborne LiDAR as ecological indicators for managing highly dynamic landscapes

An objective, quantifiable index of structural biodiversity that could be rapidly obtained with reduced or no field effort is essential for the use of structure as universal ecological indicator for ecosystem management. Active remote sensing provides a rapid assessment tool to potentially guide land managers in highly dynamic and spatially complex landscapes. These landscapes are often dependent on frequent disturbance regimes and characterized by high endemism.We propose a modified Shannon–Wiener Index and modified Evenness Index as stand structural complexity indices for surrogates of ecosystem health. These structural indices are validated at Tall Timbers Research Station the site of one of the longest running fire ecology studies in southeastern U.S. This site is dominated by highly dynamic pine-grassland woodlands maintained with frequent fire. Once the dominant ecosystem in the Southeast, this woodland complex has been cleared for agriculture or converted to other cover types, and depends on a frequent (1- to 3-year fire return interval) low- to moderate-intensity fire regime to prevent succession to mixed hardwood forests and maintain understory species diversity. Structural evaluation of the impact of multiple disturbance regimes included height profiles and derived metrics for five different fire interval treatments; 1-year, 2-year, 3-year, mixed fire frequency (a combination of 2- and 4-year fire returns), and fire exclusion. The 3-dimensional spatial arrangement of structural elements was used to assess hardwood encroachment and changes in structural complexity. In agreement with other research, 3-year fire return interval was considered to be the best fire interval treatment for maintaining the pine-grassland woodlands, because canopy cover and vertical diversity indices were shown to be statistically higher in fire excluded and less frequently burned plots than in 1- and 2-year fire interval treatments. We developed a LiDAR-derived structural diversity index, LHDI, and propose that an ecosystem-specific threshold target for management intervention can be developed, based on significant shifts in structure and composition using this new index.Structural diversity indices can be valuable surrogates of ecosystem biodiversity, and ecosystem-specific target values can be developed as objective quantifiable goals for conservation and ecosystem integrity, particularly in remote areas.     

The role of landscape history and persistent biogeographical patterns in shaping the responses of Mediterranean land snail communities to recent fire disturbances

Aims To assess the impact of various fire regimes over the past 30 years on land snail communities and to analyse the role of recent landscape history and the influence of biogeography in shaping the response patterns of gastropod communities following disturbances by fire. Location South-eastern France (Provence) and Mediterranean region. Methods Stratified sampling within 12 sites was undertaken with regard to fire regime (i.e. number of fires, fire intervals and age of the last fire) occurring over the past 30 years. The study was complemented by a historical analysis using aerial photographs, old maps of vegetation cover and an analysis of the biogeographical composition of malacofaunas. Data were investigated using Correspondence Analysis and Sørensen coefficient of similarity. Results When a disturbance regime (land use or fire disturbances) has been maintained over decades or centuries, land snail communities appear highly modified and tend to be composed of only Mediterranean and xerophilous species. However, low fire regimes, since the 1970s, do not seem to greatly affect the composition of gastropod communities. Indeed, shade-loving, mesophilous and European range species persist even after successive fires within some sites. In addition, the malacofaunas have a higher component of European range species with increasing distance from the Mediterranean sea. Main conclusions Analysis of the response patterns of gastropod communities to fire shows a response to numerous different factors. The composition of current land snail communities is not only the result of (more or less) recent patterns of fire regimes but also of anthropogenic disturbances, of landscape changes over the last centuries and of subsequent structure of the pre-fire habitat, as well as of the influence of a biogeographical gradient. However, the response patterns observed and the persistence of pre-fire communities imply the presence of cryptic refuges located within burned areas.     

Micro biochemical engineering to accelerate the design of industrial-scale downstream processes for biopharmaceutical proteins

The article examines how a small set of easily implemented micro biochemical engineering procedures combined with regime analysis and bioprocess models can be used to predict industrial scale performance of biopharmaceutical protein downstream processing. This approach has been worked on in many of our studies of individual operations over the last 10 years and allows preliminary evaluation to be conducted much earlier in the development pathway because of lower costs. It then permits the later large scale trials to be more highly focused. This means that the risk of delays during bioprocess development and of product launch are reduced. Here we draw the outcomes of this research together and illustrate its use in a set of typical operations; cell rupture, centrifugation, filtration, precipitation, expanded bed adsorption, chromatography and for common sources, E. coli, two yeasts and mammalian cells (GS-NSO). The general approach to establishing this method for other operations is summarized and new developments outlined. The technique is placed against the background of the scale-down methods that preceded it and complementary ones that are being examined in parallel. The article concludes with a discussion of the advantages and limitations of the micro biochemical engineering approach versus other methods.     

不同光质光照对香菇子实体农艺性状与质构品质的影响

香菇Lentinula edodes是世界第一大食药用真菌,随着香菇工厂化生产逐渐规模化、周年化、标准化,香菇工厂对环境集约化及智能化控制的要求也越来越高.光照是香菇生长发育过程中重要的环境因素,本研究将转色后的香菇菌棒分别置于红光(R)、绿光(G)、蓝光(B)、红绿光(RG)、红蓝光(RB)、绿蓝光(GB)、红绿蓝光...     

Regeneration failure of lakeshore plants under an artificially altered water regime

To reveal the effects of artificial alteration of water level regime on the regeneration of lakeshore plants from seeds, we examined the factors causing regeneration failure in Lake Kasumigaura, Japan. A survey of microtopography within and around a remnant fragment of lakeshore vegetation revealed that, over a large range, the habitat is frequently inundated in spring under the current water regime, although it was rarely inundated under past water regimes. Analysis of the patterns of seedling emergence and establishment at microsites at various elevations revealed a significant negative correlation between number of inundation days and abundance or species-richness of seedlings that emerged in the spring. Most seedling deaths occurred when the study site was inundated. We suggest that regeneration failure caused by the artificial raising of the lakes water level is one of the principal mechanisms of the recent vegetational decline in the lake.     

Pulse-Driven Loss of Top-Down Control: The Critical-Rate Hypothesis

In systems ranging from lakes and woodlands to coral reefs, the long-term ecosystem state may often be determined largely by rare extreme events such as wet ENSO years, droughts, or disease outbreaks. Such events can flip these systems into a contrasting state that represents either an alternative attractor or a transient that is slow enough to persist even if the frequency of events that push the system to this state is low. Here we show that escape from herbivores is a mechanism that can play a role in several state shifts of this kind. This can happen if plants become less susceptible to herbivory as they grow. Using a model we show that, surprisingly, this mechanism can lead to a situation where a brief resource pulse for plants may invoke a persistent shift to a high biomass state whereas gradual enrichment to the same resource level is insufficient to allow such a change. This counterintuitive phenomenon occurs if the numerical response of herbivores is sufficiently slow to allow the plants to use the resource pulse to escape to a safe biomass at which herbivory is reduced. Our results imply that rates of environmental change can sometimes be more important than their magnitude. This has many ramifications. On the conceptual side, our findings suggest that key mechanisms that regulate long-term ecosystem dynamics are easily missed by the traditional focus of modelers on equilibria. A more practical corollary is that increased climatic variability may have more profound effects in some ecosystems than gradual change in conditions.