排序方式： 共有27条查询结果，搜索用时 15 毫秒
21.
Annelies De Backer Stefanie Adam Jaak Monbaliu Erik Toorman Magda Vincx Steven Degraer 《Estuaries and Coasts》2009,32(6):1121-1129
The present study aims to test the application of remote sensing to address the impact of bioturbation on physical sediment
properties. Therefore, a laboratory experiment was developed, using microcosms mimicking a marine intertidal water–sediment
interface to test the influence of Corophium volutator densities on sediment properties. Three main variables (water content, clay content, and mean grain size) were measured in
three treatments (no Corophium, 5,000 Corophium per square meter, and 20,000 Corophium per square meter) after 16 days of bioturbation. Results obtained with conventional—destructive—techniques showed a significant
increase of water content and a significant, but small decrease of clay content in the presence of Corophium. The remote sensing technique detected the impact of Corophium on water content as an increase in absorption at 1,450 nm, but was not able to detect the animal impact on clay content.
This study demonstrates that remote sensing data could be significantly modified by bioturbation activities and that remote
sensing can be applied in the laboratory to address the impact of bioturbation on sediment properties. This possibly opens
new perspectives for long-term experiments concerning the role of bioturbation on sedimentary processes. 相似文献
22.
S. Degraer E. Verfaillie W. Willems E. Adriaens M. Vincx V. Van Lancker 《Continental Shelf Research》2008
Being ecologically important and well-known, the spatial distribution pattern of the macrobenthos is often used to support an ecologically sustainable marine management. Though in many cases the macrobenthic spatial distribution is relatively well-known, this information is merely restricted to point observations at the sampling stations: although being increasingly demanded, full coverage spatial distribution maps are generally lacking. This study therefore aimed at demonstrating the usefulness of habitat suitability modelling as a full coverage mapping tool with high relevance for marine management through (1) the construction of a habitat suitability model for the soft sediment macrobenthic communities in the Belgian part of the North Sea (BPNS) and (2) predicting the full coverage spatial distribution of macrobenthic communities within the BPNS. The BPNS was selected as a case study area because of the high data availability on both macrobenthos and environmental characteristics. Discriminant function analysis (DFA) objectively selected median grain size and sediment mud content and omitted bathymetry, slope and distance to the coast to represent the most important environmental variables determining the macrobenthic community distribution. The consequent crossvalidated, empirical habitat suitability model, using both median grain size and mud content, showed an a posteriori average correctly classified instances (CCI) of 79% (community-dependent CCI ranging from 72% to 86%) and a Cohen's kappa of 0.71, pointing towards a very good agreement between model predictions and observations. The application of the habitat suitability model on the full coverage maps of median grain size and sediment mud content, taken from literature, allowed to reliably assess the distribution of the macrobenthic communities within 96.3% of the 53,297 BPNS grid cells with a resolution of 250 m. Next to its applicability to the BPNS, the model is further anticipated to potentially perform well in the full Southern Bight of the North Sea: testing is advised here. Since the habitat suitability is considered far more stable through time compared to the permanently fluctuating macrobenthic communities, information on the habitat suitability of an area is considered highly important for a scientifically sound marine management. 相似文献
23.
Lagring R Degraer S de Montpellier G Jacques T Van Roy W Schallier R 《Marine pollution bulletin》2012,64(3):644-652
Over the years many policy measures have been taken to prevent illegal oil discharges from ships, like the MARPOL 73/78 Convention (1983) and the Bonn Agreement (1969/1983). However, the number of discharges remained high, leading to chronic oiling of seabirds and sensitive coastlines, therefore further measures were taken. The aim of this study is to quantify the effectiveness of two key legislative regulations: the IMO-designation of the North Sea as MARPOL Special Area which took effect in 1999, and the adoption of the EU Directive on Port Reception Facilities in 2000. Under study is the heavily navigated Belgian Surveillance Area, monitored since 1991, characterised by shallow waters with ecologically important sandbanks. The aerial surveillance data from 1991 to 2010 show a stepwise decrease in ship-source oil pollution. Three time periods can be distinguished with two turning points coinciding with the actual implementation of these key legislative measures, confirming their effectiveness. 相似文献
24.
Paolo Paruolo Ben Murphy Greet Janssens-Maenhout 《Stochastic Environmental Research and Risk Assessment (SERRA)》2015,29(1):93-107
This paper analyzes the relation between income and emissions in the period 1970–2008, for all world countries. We consider time-series of CO2, SO2 and GWP100, and use Vector Autoregressive models that allow for nonstationarity and cointegration. At 5 % significance level, income and emissions are found to be driven by unrelated random walks with drift (respectively by a common random walk with drift) in about 70 % (respectively 25 %) of cases; in the remaining cases the variables are trend-stationary. Tests of Granger-causality show evidence of both directions of causality. For the case of unrelated stochastic trends, we almost never find income driving emissions, as predicted by a consumption-function interpretation. These causality results and the absence of a common trend challenge the main implications of the Environmental Kuznets Curve, namely that the dominant direction of causality should be from income to emissions, and that for increasing levels of income, emissions should tend to decrease. 相似文献
25.
Heliana Teixeira Ángel Borja J. Ananda Ranasinghe Daniel M. Dauer Steven Degraer Antoine Grémare Roberto J. Llansó João C. Marques Anna Occhipinti-Ambrogi Rafael Sardá Ronald G. Velarde 《Marine pollution bulletin》2010,60(4):589-600
Benthic indices are typically developed independently by habitat, making their incorporation into large geographic scale assessments potentially problematic because of scaling inequities. A potential solution is to establish common scaling using expert best professional judgment (BPJ). To test if experts from different geographies agree on condition assessment, sixteen experts from four regions in USA and Europe were provided species-abundance data for twelve sites per region. They ranked samples from best to worst condition and classified samples into four condition (quality) categories. Site rankings were highly correlated among experts, regardless of whether they were assessing samples from their home region. There was also good agreement on condition category, though agreement was better for samples at extremes of the disturbance gradient. The absence of regional bias suggests that expert judgment is a viable means for establishing a uniform scale to calibrate indices consistently across geographic regions. 相似文献
26.
The use of benthic indicators in Europe: from the Water Framework Directive to the Marine Strategy Framework Directive 总被引：1，自引：0，他引：1
Van Hoey G Borja A Birchenough S Buhl-Mortensen L Degraer S Fleischer D Kerckhof F Magni P Muxika I Reiss H Schröder A Zettler ML 《Marine pollution bulletin》2010,60(12):2187-2196
The Water Framework Directive (WFD) and the Marine Strategy Framework Directive (MSFD) are the European umbrella regulations for water systems. It is a challenge for the scientific community to translate the principles of these directives into realistic and accurate approaches. The aim of this paper, conducted by the Benthos Ecology Working Group of ICES, is to describe how the principles have been translated, which were the challenges and best way forward. We have tackled the following principles: the ecosystem-based approach, the development of benthic indicators, the definition of ‘pristine’ or sustainable conditions, the detection of pressures and the development of monitoring programs. We concluded that testing and integrating the different approaches was facilitated during the WFD process, which led to further insights and improvements, which the MSFD can rely upon. Expert involvement in the entire implementation process proved to be of vital importance. 相似文献
27.
Community structure and intertidal zonation of the macrobenthos on a macrotidal, ultra-dissipative beach were studied. On
the beach of De Panne, Belgium, six transects perpendicular to the waterline (each with five stations) were sampled in September
1995 (summer) and March 1996 (winter). The 30 stations were distributed across the continuum from mean high water spring to
mean low water spring in order to sample the macrobenthos at different levels of elevation. The 39 species found had total
densities up to 5,500 ind m−2 in summer and 1,400 ind m−2 in winter. The highest densities were found in the spionid polychaetesScolelepis squamata andSpio filicornis, the nephtyid polychaeteNephtys cirrosa, the cirolanid isopodEurydice pulchra, and the haustorid amphipodsBathyporeia spp. Based on species composition, specific densities, and biomass, two species associations were defined: a relatively species-poor,
high intertidal species association, dominated byS. squamata and with an average density of 1,413 ind m−2 and biomass of 808 mg AFDW m−2 (summer); and a relatively species-rich, low intertidal species association, dominated byN. cirrosa, and with an average density of 104 ind m−2 and biomass of 162 mg AFDW m−2 in summer. For both seasons, the high intertidal species association was restricted in its intertidal distribution between
the mean tidal and the mean high-water spring level, whereas the low intertidal species association was found from the mean
tidal level to the subtidal. The latter showed good affinities with the subtidalN. cirrosa species association occurring just offshore of De Panne beach, confirming the existence of a relationship between the low
intertidal and subtidal macrobenthic species associations. Summer-winter comparison revealed a strong decrease in densities
and biomass in the high intertidal zone during winter. Habitat continuity of the low intertidal zone with the subtidal allows
subtidal organisms to repopulate the low intertidal zone. 相似文献