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91.
- 1. Although Chile is at the forefront in evaluating experimentally the importance of human harvesting impacts on coastal biodiversity, there are no evaluations of such impacts on a long‐term historical basis (tens to thousands of years). Different types of archival information (i.e. contemporaneous, archaeological, and palaeontological) were used to carry out a research programme based on the historical assessment of the impacts and intensity of resource extraction on coastal biodiversity along the Chilean coast.
- 2. In addition to recent scientific literature, different sources of contemporaneous information (e.g. museum collections, old reports and accounts) can reveal the human impacts observed in the more recent past. Furthermore, the large number of prehistoric shell middens along the entire Chilean coast offer access to ~11 000 years of history along the entire coast, although the faunal composition, structure, and dynamics of most of them remain largely unstudied.
- 3. Finally, the rich and widespread fossil record of some marine groups provides the opportunity to reconstruct the structure and dynamics of benthic communities during different phases of human influence (e.g. pre‐human, prehistoric harvesting, and modern harvesting).
- 4. Preliminary comparisons of fossil versus modern bivalve assemblages suggest marked changes in the species composition. Human impacts seem very recent and shifts in the structure of benthic assemblages may have occurred only a few centuries/decades ago.
- 5. In contrast, prehistoric harvesting, although intense, was apparently not enough to cause a profound impact on coastal ecosystems. The approach herein envisaged can provide the basis to build a historical baseline to evaluate the human impacts on the coastal biodiversity in the region. Copyright © 2009 John Wiley & Sons, Ltd.
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Mechanisms of glyphosate resistance and response to alternative herbicide‐based management in populations of the three Conyza species introduced in southern Spain
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Carlos Sanz-Lazaro Victoria Fernandez-Gonzalez Pablo Arechavala-Lopez David Izquierdo-Gomez Elena Martinez-Garcia Pablo Sanchez-Jerez 《Aquaculture International》2018,26(5):1161-1170
Bivalve cultivation, in single cultivation or in polyculture (including integrated multitrophic aquaculture; IMTA), is generally limited to eutrophic waters. We carried out a modeling study to test if, under meso- and oligotrophic conditions, depth could be a key factor for bivalve productivity associated to IMTA and other polyculture strategies. We applied the model Farm Aquaculture Resource Management (FARM) at three strata of the water column in two coastal fish farm areas in the Mediterranean Sea, using water column variables sampled seasonally to estimate the potential mussel production. According to FARM, mussel production was high in both areas and, in some cases, almost doubled when mussels were cultured below 25-m depth compared to shallower levels. Phytoplankton abundance is expected to notably influence mussel production compared to particulate organic matter. Thus, in meso- and oligotrophic stratified waters, where chlorophyll maximum is relatively deep, depth can be a key factor for the productivity of mussel cultivation. The obtained results could help to maximize the production of suspension-feeding bivalve cultivation and, therefore, the expansion and development of sustainable aquaculture in non-eutrophic marine waters. 相似文献
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不同碳氮有机物料对有机菜田土壤细菌多样性的影响 总被引:1,自引:1,他引:0
通过模拟试验,利用聚合酶链式反应-变性梯度凝胶电泳法(PCR-DGGE),研究了施入不同碳氮有机物料(秸秆、苜蓿、有机肥、尿素)56d后,有机生产系统菜田土壤细菌群落结构的特征。结果表明,常规和有机生产系统土壤的细菌群落结构有明显差异。由DGGE图谱ShannonWiener多样性指数分析得知,有机背景处理的细菌多样性整体高于常规背景处理,且有机生产系统土壤加秸秆处理(OS)多样性最高,加入尿素后细菌多样性降低,相反,加入苜蓿后细菌多样性升高。非加权组平均法(UPGMA)聚类分析将常规和有机背景土壤分为两大族群。DGGE条带测序和系统进化树表明,30个条带归属为Proteobacteria、Acidobacteria、Actinobacteria、Firmicutes、Verrucomicrobia。常规土壤加苜蓿(CA)处理出现的特征性条带B13与有机背景处理的共有条带B28分别与Bacillus属和Pseudomonas假单胞菌属同源性最高。 相似文献
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Anaerobic co‐digestion of perennials: Methane potential and digestate nitrogen fertilizer value
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Dorette Sophie Müller‐Stöver Guotao Sun Pablo Kroff Sune Tjalfe Thomsen Henrik Hauggaard‐Nielsen 《植物养料与土壤学杂志》2016,179(6):696-704
Co‐digestion of crop biomass improves the traditional manure‐based biogas yield due to an increased content of easily degradable carbon compounds. In this study, the methane potential of three perennials (grass, legumes, and grass+legume) was determined using various amounts together with animal manure. The nitrogen (N) mineralization dynamics in soil and the N‐fertilizer value of the derived digestates were subsequently tested in both a soil incubation study and a pot experiment with spring barley. Digestion of all tested perennials together with a manure‐based inoculum increased the cumulative methane yield four to five times compared to digestion of the inoculum alone, with the highest increases observed with pure grass. However, the methane potential decreased along with increasing grass biomass concentration. In the plant pot experiment, all tested digestates increased barley shoot biomass by 40–170%, to an extent statistically comparable to mineral N fertilizer. However, the application of the digestate originating from fermentation with pure grass resulted in lower plant growth and a more fluctuating soil mineral N content throughout the incubation study compared to the other digestates. Considering the high dry matter and methane yield ha?1, the possibility to substitute mineral N fertilizer inputs by leguminous biological N2 fixation capacity, and the digestate fertilizer value, the integration of grass–legume mixtures or sole legumes into anaerobic digestion systems as co‐substrate for manure seems to be promising. This could furthermore contribute to the diversification of cropping systems for bioenergy production. 相似文献