Chemical cues promote settlement in larvae of the green-lipped mussel, Perna canaliculus

The large (70,000 tonnes) mussel aquaculture industry for the endemic New Zealand green-lipped mussel, Perna canaliculus Gmelin, currently relies almost entirely (80%) on wild caught seed that is often harvested attached to great quantities of floating algae. Natural vagaries in catches of wild mussel seed frequently result in shortages of mussel seed that, at times, have severely affected commercial aquaculture production. Both field and laboratory experiments were used to establish that chemical cues derived from algae significantly increase settlement of mussel larvae on artificial substrates. This is the first time an algal chemical cue has been implicated in the settlement behavior of P. canaliculus larvae. These results have potential commercial implications for improving mussel seed supply through inducing higher or more reliable levels of mussel settlement for aquaculture seed collection.     

Larval rearing of calico scallops, Argopecten gibbus, in a flow-through system

A flow-through (FT) culture system is described for calico scallop, Argopecten gibbus, larvae. Its performance was assessed by larval survival rate, shell growth, settlement rate and post-larval shell growth for the duration of larval life (13 days). Comparisons were made with larvae reared in standard static system (S). Effect of increased larval density on FT performance was also investigated. With comparable larval densities, survival rate of Day 2 larvae to pediveliger stage was similar in both larval rearing systems. Shell growth for FT-reared larvae was comparable or significantly higher than in the static system (P < 0.01). Settlement rate of pediveligers was comparable for both systems, averaging 30.7%, and no significant difference was seen in shell growth of FT- and static-reared pediveligers. Increased initial larval density did not affect survival rate in FT, but did negatively affect larval shell growth, settlement rate and post-larval shell growth yielding lower growth and minimal settlement rate (10.9 ± 2.8%) compared to the static system. This FT system was successful as larval rearing system, optimising space allocation in the hatchery, reducing labour, and eliminating the use of antibiotics. Optimising initial larval density within the system needs to be investigated in association with food ration.     

浅基础在大兴安岭林区应用的探讨

本文对大兴安岭林区冻害原因进行了分析。根据工程实例证明,在大兴安岭林区,根据不同的地质条件,在该地区大量应用浅基础是可能的,这样在该地区的许多工程构造物基础可从3.25m(该地区冻结深度为3.00m)降到1—1.5 m,从而使工程造价降低10％左右。因而可以取得明显的经济效益。最后论述了浅基础的应用条件,对林区应用浅基础有一定借鉴作用。     

Habitat use, growth, and mortality of post-settlement lane snapper (Lutjanus synagris) on natural banks in the northwestern Gulf of Mexico

Three low-relief banks in the northwestern Gulf of Mexico were evaluated as nursery habitat of lane snapper (Lutjanus synagris). Trawl surveys were conducted in three habitat types (inshore mud, shell ridge, offshore mud) to quantify lane snapper distribution and abundance. Heald Bank and Sabine Bank were trawled in 2003 while Freeport Rocks was trawled in 2000 (Freeport A) and 2004 (Freeport B). Density of lane snapper varied among banks and years sampled: Sabine Bank (20.8 ± 2.8 ind ha⁻¹), Heald Bank (1.1 ± 0.4 ind ha⁻¹), Freeport A (12.7 ± 2.3 ind ha⁻¹), and Freeport B (3.0 ± 1.0 ind ha⁻¹). Habitat-specific differences in density were observed, although patterns were not consistent among banks. Otolith microstructure analysis indicated that post-settlement lane snapper ranged in age from 21 to 66 d, with hatch dates from 1 May to 31 August. Growth rates varied from 0.90 mm d⁻¹ at Heald Bank to 1.27 mm d⁻¹ at Sabine Bank, and habitat-specific differences in growth were negligible. Mortality of post-settlement lane snapper ranged from 15.2% d⁻¹ at Sabine Bank to 9.2% d⁻¹ at Freeport A. Our findings indicate that Heald Bank, Sabine Bank, and Freeport Rocks all serve as settlement habitat of lane snapper, which appear to be capable of successful settlement across a variety of habitats.     

Estimating Settlement carbon stock and density using an inventory approach and quantifying their variation by land use and parcel size

A lack of very-high resolution land-cover data and in-situ carbon sampling in Settlement areas has limited the quantification of terrestrial carbon in Canadian Settlements and elsewhere. Without those data, it is difficult to quantify Settlement area terrestrial carbon for United Nations Framework Convention on Climate Change reporting within the Land Use, Land Use Change, and Forestry sector. The presented research takes a step toward filling this gap by first classifying Settlement land cover at a very-high resolution (<=80 cm, 93% overall accuracy). Then, with those data, an inventory approach is used to estimate carbon stocks based on local data, standard rulesets from the IPCC, and practice-based assumptions. Guided by FAIR principles, our approach is operationalized and available in a Jupyter Notebook for distribution, use, and extension by others. Results found that the study Settlement comprised 30% tree cover and 18% turfgrass. When analyzed by parcel size, carbon densities varied little for parcels less than 1.6 ha (3.9–4.2 kg C m^-2), but then increased with larger parcels up to 6.6 Gg C m^-2 for parcels > 8.1 ha. Among different land uses, industrial, commercial, and transportation had the lowest carbon densities (2.4–2.8 kg C m^-2), followed by high, medium, and low-density residential (3.6, 4.0, 8.9 kg C m^-2, respectively) with low-density residential almost achieving carbon densities in protected and recreation areas (10.2 kg C m^-2). Our results suggest that land use is a stronger driver of carbon-storage relative to parcel size, but their combination best represents the variation in carbon-storage in low-density residential land use. Currently, only carbon change in urban trees and deforestation around urban centres is reported in Canada’s National GHG Inventory Report. The present research quantifying carbon densities provides an analysis that could inform carbon change resulting from other land-use conversions and improve deforestation estimates by better defining the final state of a land-use change.     

园林工程中创新技术、新材料的应用及项目管理探析——以深圳万科前海企业公馆园林景观建设工程为例

随着我国生态文明建设步伐地不断前行,高品质且环保的园林景观工程在美化城市和生态环境建设中具有重要的作用,同时也是城市形象的重要展示窗口。该文以深圳万科前海企业公馆园林建设工程项目为例,阐明园林新技术新材料应用及施工管理、安全文明施工、资料管理和结算管理等项目管理方法对于成就精品园林景观工程的重要性。以期为园林景观精品工程项目开展提供项目管理思路和技术参考,为生态宜居城市建设奠定基础。     

Simulated village locations in Thailand: a multi-scale model including a neural network approach

The simulation of rural land use systems in general, and rural settlement dynamics in particular, has developed with synergies of theory and methods for decades. Three current issues are: linking spatial patterns and processes, representing hierarchical relations across scales, and considering nonlinearity to address complex non-stationary settlement dynamics. We present a hierarchical simulation model to investigate complex rural settlement dynamics in Nang Rong, Thailand. This simulation uses sub-models to allocate new villages at three spatial scales. Regional and sub-regional models, which involve a nonlinear space–time autoregressive model implemented in a neural network approach, determine the number of new villages to be established. A dynamic village niche model, establishing a pattern–process link, was designed to enable the allocation of villages into specific locations. Spatiotemporal variability in model performance indicates that the pattern of village location changes as a settlement frontier advances from rice-growing lowlands to higher elevations. Simulation experiments demonstrate that this simulation model can enhance our understanding of settlement development in Nang Rong and thus gain insight into complex land use systems in this area.     

新时代新疆南疆农村人居环境整治效果研究

摘要：农村人居环境整治是乡村振兴的一个重大目标,对新时代新疆南疆人民的生活水平及人居环境安全有着重大的影响。本文基于新时代新疆南疆农村人居环境整治的时代价值,国家颁布的相关政策实施情况,以及整治模式进行深入的调查研究。从人居环境整治现状及存在的问题出发,农民应该提高集体意识,提升文化和技术水平,采取第三方监察监管机制等相应对策建议。最后对新时新疆南疆农村人居环境整治效果未来进行合理的展望,始终不忘初心,牢记使命,建设气象万千的美丽中国。     

Effects of different substrates on settlement and growth of pearl oyster (Pinctada maxima) larvae in hatcheries

Metamorphosis of pearl oyster Pinctada maxima pediveliger is affected by physical and chemical characteristics of the collectors. In the present study, we conducted four experiments to evaluate the effects of collector characteristics on the settlement and growth of hatchery-reared pearl oyster. In the first experiment, black, red, yellow, and white plastic sheets were used as collectors. Settlement of P. maxima larvae in black and red plastic sheets was significantly higher than that in yellow and white plastic sheets (P < 0.05). Mean shell length was not significantly different among the four colored sheets (P > 0.05). In the second experiment, pediveliger larvae were settled onto palm rope and polypropylene rope collectors. The number of spat in the palm rope collector was significantly higher than that of spat in the polypropylene rope collector (P < 0.05). Mean shell length was not significantly different between palm rope and polypropylene rope collectors (P > 0.05). In the third experiment, settlement and subsequent growth were compared between plastic sheets with and without biofilm. The number of spat in the plastic sheets with biofilm was significantly higher than that in the plastic sheets without biofilm (P < 0.05). Mean shell length after settlement were not significantly affected (P > 0.05). In the fourth experiment, pediveliger larvae were stored in tanks with (experimental group) and without collectors (control group). The settlement rate of larvae on the wall was not significantly different between the two groups(P > 0.05). The settlement rates of the larvae on the wall and collectors in the experimental group were significantly larger than those on the wall in the control group(P < 0.05). Mean shell length was not significantly different between the groups (P > 0.05). Our results suggest that appropriate selection of collector types, color, and conditioning can improve the settlement of P. maxima larvae in hatcheries.     

生物淋滤法对污泥中镉去除及污泥性质的影响

[目的]研究生物淋滤对污泥中镉的去除效率及污泥性质的影响,探讨生物淋滤法对污泥中镉的去除效率和机制。[方法]通过淋滤前后污泥养分含量、沉降性能和脱水性能的变化研究了生物淋滤对污泥性质的影响。[结果]结果表明,生物淋滤法对污泥中镉的去除效率在60％左右,生物淋滤去除了污泥中以碳酸盐结合态和有机质结合态存在的镉,使污泥中交换态镉的比例提高到58％,活性增强。生物淋滤能改善污泥的沉降性能和脱水性能,但使污泥的有机质、氮、磷和钾含量分别降低50．92％、68．86％、52．42％和41．22％。[结论]为城市污泥农地资源化利用提供技术支撑。