An environmental assessment of risk in achieving good environmental status to support regional prioritisation of management in Europe     

P. Breen  L.A. Robinson  S.I. Rogers  A.M. Knights  G. Piet  T. Churilova  P. Margonski  N. Papadopoulou  E. Akoglu  A. Eriksson  Z. Finenko  V. Fleming-Lehtinen  B. Galil  F. Goodsir  M. Goren  O. Kryvenko  J.M. Leppanen  V. Markantonatou  S. Moncheva  T. Oguz  L. Paltriguera  K. Stefanova  F. Timofte  F. Thomsen 《Marine Policy》2012

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Resource depletion affects the structure of an experimental benthic food web     

《Limnologica》2016

In this study, we investigated the long-term (2-year) response of a detritus-based food web to resource depletion simulated in microcosms filled with lake sediment. The effects of resource depletion on the food web were estimated from the biomass responses of a simplified, size-based trophic network comprising three trophic levels: (1) bacteria, (2) bacterivorous meiofauna, and (3) omnivore/predacious nematodes and oligochaetes. The results showed that sediment bacteria and organic carbon stock were not affected by resource depletion, whereas oligochaetes, large nematodes and some bacterivores, such as rotifers and ostracods, decreased dramatically. At the same time, resource depletion had no negative effect on minute bacterivorous nematodes and harpacticoid copepods, suggesting their release from competition with other bacterivores and/or their release from potential predation by large nematodes and oligochaetes. Our results globally confirmed classical trophic dynamics models in which a shortage in resources dampens food-chain length. Yet, low resources did not completely eliminate all large invertebrates, and did not affect the standing stock of detritus and bacteria, suggesting that detritus-based food webs could show a remarkable resilience to the effects of resource depletion.  相似文献   

How can marine ecosystem services support the Blue Growth agenda?     

《Marine Policy》2017

The EU Blue Growth Agenda targets maritime economic activities that have the sea and the coasts as drivers. These activities are supported by marine Ecosystem Services (ES) in combination, or not, with abiotic outputs from the marine natural capital. This paper analyses Blue Growth activities with regards to the demand and supply of marine ES and Good Environmental Status (GES). The results show that marine provisioning ES support aquaculture and blue biotechnology, while blue energy is supported by marine provisioning ES and by abiotic provisioning, and abiotic provisioning supports extraction of marine mineral resources. Maritime, coastal and cruise tourism is supported by cultural marine ES and cultural settings dependent on marine abiotic structures. All these multi-sectoral economic activities depend on healthy marine and coastal ecosystems that are provided by regulating and maintenance ES combined with the abiotic regulation and maintenance by natural marine physical structures and processes. In order to balance concurrent sectoral interests and achieve sustainable use of marine resources there is the need to consider indicators for demand for ES, which are social and economically driven, and for the supply, which are dependent on ecosystems capacity to provide the required marine ES. Some of the actions foreseeing GES are already anticipated in legislation that underpin Blue Growth, whilst others could benefit from additional regulation, particularly in what concern the exploration and exploitation of marine mineral and biological resources. Blue Growth options require navigating trade-offs between economic, social and environmental aspects.  相似文献   

Bacterioplankton and phytoplankton production in seven lakes in the Middle Rio Doce basin, south-east Brazil     

Mauricio M. Petrucio  Francisco A.R. Barbosa 《Limnologica》2006,36(3):192-203

The purpose of this study was to measure the phytoplankton production (PP) and bacterial production (BP) simultaneously in seven lakes in the middle Rio Doce basin (southeast Brazil) during the dry and the rainy seasons. Limnological monitoring was conducted from 1999 to 2001 as well as both PP (radioactive carbon fixation) and BP (³H-Leucine incorporation) in four specific depths (100%, 10%, 1% of incident radiation, and aphotic zone). Furthermore, trophic state of the lakes was analyzed, considering the index proposed by Salas and Martino (1991) and Carlson (1977). In general, some parameters increased during the rainy season such as pH, conductivity, chlorophyll and total nitrogen. In the period of 1999/2000, the rain caused PP reduction in the lakes, excepting Carioca and Águas Claras Lake, but in the years 2000/2001, the lakes did not show a similar pattern. In contrast, the rainy season of both years caused an expressive bacterioplankton production enhancing. Using Salas and Martino index, we observed that some lakes were affected by the seasonal runoff, therefore the typologie of these lakes changed from oligotrophic to mesotrophic conditions, otherwise considering the Carlson index all lakes were classified as eutrophic in both dry and rainy seasons. Indeed, Salas and Martino index demonstrated to be more appropriate to determine the trophic status of the lakes. Finally, our data indicate that until now, in spite of the lakes location, protected and unprotected area, the lakes still maintain their natural characteristics.  相似文献   

Expanding the concept of trophic state in aquatic ecosystems: It’s not just the autotrophs   总被引：1，自引：0，他引：1  

Walter K. Dodds  Jonathan J. Cole 《Aquatic Sciences - Research Across Boundaries》2007,69(4):427-439

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Top-down modeling and bottom-up dynamics: Linking a fisheries-based ecosystem model with climate hypotheses in the Northern California Current   总被引：3，自引：2，他引：3  

J.C. Field  R.C. Francis  K. Aydin 《Progress in Oceanography》2006,68(2-4):238

In this paper we present results from dynamic simulations of the Northern California Current ecosystem, based on historical estimates of fishing mortality, relative fishing effort, and climate forcing. Climate can affect ecosystem productivity and dynamics both from the bottom-up (through short- and long-term variability in primary and secondary production) as well as from the top-down (through variability in the abundance and spatial distribution of key predators). We have explored how the simplistic application of climate forcing through both bottom-up and top-down mechanisms improves the fit of the model dynamics to observed population trends and reported catches for exploited components of the ecosystem. We find that using climate as either a bottom-up or a top-down forcing mechanism results in substantial improvements in model performance, such that much of the variability observed in single species models and dynamics can be replicated in a multi-species approach. Using multiple climate variables (both bottom-up and top-down) simultaneously did not provide significant improvement over a model with only one forcing. In general, results suggest that there do not appear to be strong trophic interactions among many of the longer-lived, slower-growing rockfish, roundfish and flatfish in this ecosystem, although strong interactions were observed in shrimp, salmon and small flatfish populations where high turnover and predation rates have been coupled with substantial changes in many predator populations over the last 40 years.  相似文献   

我国热带生物海岸的现状及生态系统的修复与重建   总被引：16，自引：0，他引：16  

张乔民 《海洋与湖沼》2001,32(4):454-464

评述了以红树林和珊瑚礁为代表的我国热带生物海岸的分布及其面积、生物群落的破坏、海岸保护与管理、科学研究等各个方面的现状，以及生态系统修复与重建技术研究进展，指出热带生物海岸及其上的红树林、珊瑚礁热带海岸生态系统具有特殊的资源价值和生态效益，对热带海岸社会经济可持续发展的十分重要；另一方面对日益频繁的人类开发活动和自然环境变异十分敏感和脆弱，而且其直接经济价值相对较低而通常易于被忽视，随着我国自然环境变异十分敏感和脆弱，而且其直接经济价值相对较低而通常易于被忽视，随着我国社会经济近20年来的快速发展，导致热带海岸地区人口、资源、环境压力加剧，热带生物海岸红树林和珊瑚礁资源已经受到生态破坏性开发活动的极大破坏而急需保护。尽管政府采取了保护管理的各种措施，包括相关法律、自然保护区、科学研究、生态系统修复与重建的实验、研究和推广，但是总体上衰退的趋势尚未扭转，热带生物海岸在我国河口海岸生态环境变异和资源可持续利用研究中具有特别重要要的意义，应该加强我国热带生物海岸的调查、监测、评估、研究，以适应热带生物海岸和相关生态系统的保护、管理、恢复、重建和可持续发展的紧迫要求。  相似文献   

Trophieindikation in Fließgewässern mit Hilfe des TIM (Trophie‐Index Makrophyten) – Erprobung eines neu entwickelten Index im Inninger Bach     

S. Schneider  Th. Krumpholz  A. Melzer 《洁净——土壤、空气、水》2000,28(5):241-249

Indicating the Trophic State of Running Waters by Using TIM (Trophic Index of Macrophytes) – Exemplary Implementation of a New Index in the River Inninger Bach The river Inninger Bach represents the outflow of the lake Wörthsee (Bavaria). The mean pH of the calcareous river has a value of ca. 8 during the vegetation period, the mean conductivity is about 350 to 400 μS/cm. The macrophyte vegetation of the river course was mapped and the nutrient concentrations of both the water body and the sediment were measured. In every mapping section the Trophic Index of Macrophytes (TIM) was calculated. By cluster analysis the mapping sections were grouped into three zones which differed in macrophyte vegetation. These differences are not associated with varying nutrient concentrations but are mainly due to differences in the degree of shading. In spite of the characterisation of the lake Wörthsee as oligo‐mesotrophic the river Inninger Bach, which represents the outflow of the lake Wörthsee, is classified as meso‐eutrophic by the Trophic Index of Macrophytes TIM. The increased trophic state of the river compared to the lake is caused by the river Krebsbach, a small tributary flowing into the river Inninger Bach only a short stretch downstream of its outflow of the lake Wörthsee. The river Krebsbach shows a total phosphorus concentration of about 56 μg/L P. The input of diaspores of submerged macrophytes both from the oligo‐mesotrophic lake Wörthsee and the eutrophic river Krebsbach leads to a submerged vegetation comprising species with different optima in regard to the trophic situation. This is one of the main reasons why many values of the TIM have to be labeled as “not sure”.  相似文献   

砂旋复花的防风固沙作用   总被引：4，自引：0，他引：4  

韩广 《中国沙漠》1995,15(3):273-277

砂旋复花是一种沙生先锋多年生草本植物,营养繁殖能力极强,能很好地适应恶劣的流沙环境。研究结果表明,砂旋复花群聚的防风固沙作用非常突出,作为一种优良固抄植物,值得在北方沙区大力推广。  相似文献   

Shallow lake trophic status linked to late Holocene climate and human impacts   总被引：1，自引：1，他引：0  

Matthew N. Waters  Michael F. Piehler  Antonio B. Rodriguez  Joseph M. Smoak  Thomas S. Bianchi 《Journal of Paleolimnology》2009,42(1):51-64

Lake Mattamuskeet, North Carolina, USA is a large (162 km²) and shallow (mean depth = 1 m) coastal lake, which was significantly modified to support agricultural activities following European settlement in 1850. Paleolimnological proxies measured on a 400-cm sediment core collected from Lake Mattamuskeet reveal shifts in organic matter input and primary producer community structure in response to climatic and human impacts on the lake during the late Holocene. Stratigraphic changes in organic matter content, nutrients, metals, lignin phenols and photosynthetic pigments were used to divide the sediment core into three intervals. Interval I includes sediment deposited between A.D. 360–1584 and indicates a clear-water, sand-bottom state with low algal abundance. In addition, the lake catchment area experienced two significant fires during this interval that were recorded as charcoal layers in the core around A.D. 360 and A.D. 1435 (calibrated ¹⁴C AMS dates). Trophic structure changed with the onset of Interval II (A.D. 1584–1860) when total algal abundance increased, and the primary producer community was comprised primarily of diatoms, chrysophytes, cryptophytes and cyanobacteria. During this interval there was also an increase in terrestrial organic material input into the lake as well as a shift in plant type from woody gymnosperms to non-woody angiosperms as determined from lignin data. Sediment deposited in Lake Mattamuskeet following European settlement (Interval III, A.D. 1860-present) suggests a dramatic increase in organic-matter deposition, metals, primary-producer abundance and the onset of cyanobacterial dominance. Sedimentary evidence indicates that shallow-water primary producers can respond rapidly to climate change and human development.  相似文献