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1.
Sugar kelp (Saccharina latissima) forests have an important ecological function in the coastal zone, as they inhabit a high number and a specific composition of fauna. In 2002, a large-scale disappearance of sugar kelp was observed in Skagerrak and parts of the south-western coast of Norway, and the perennial sugar kelp forests were replaced by opportunistic and ephemeral filamentous algae. For management purposes, including identifying areas for restoration initiatives, maps of where sugar kelp forests are supposed to be found and where and under what conditions they have disappeared are needed. Based on modelled and field-measured geophysical variables and presence/absence/loss data of sugar kelp, we therefore developed spatial predictive probability models (i.e. maps) for sugar kelp potential distribution under natural conditions and areas of kelp loss. The influence of geophysical factors was analysed using generalized additive models (GAMs). Using the Akaike Information Criterion (AIC) for model selection, we found that wave exposure, depth, light exposure and slope best explained the potential distribution of sugar kelp. Areas of sugar kelp disappearance were identified by the combined effect of wave and light exposure. These models were developed into maps presented to the managers. 相似文献
2.
T. Bekkby H.C. Nilsson F. Olsgard B. Rygg P.E. Isachsen M. Isus 《Estuarine, Coastal and Shelf Science》2008,79(4):631-636
Macrofauna composition and diversity in soft sediments are commonly used as “health indicators” in various pollution monitoring programmes worldwide. Hence, finding a modelling method for predicting the presence of soft sediments and enable production of digital maps of where soft sediments are likely to be found would be valuable for developing a cost-effective sampling design. This study presents a first-generation model that can predict where to find soft sediments in coastal areas with a complex topography and a mosaic of seabed habitat types. We used geophysical data that were quantitative, objectively defined (through GIS modelling) and integrated over time. We analysed, using a Generalised Additive Model (GAM) and the model-selection approach Akaike Information Criterion (AIC), the influence of in-situ measured depth and GIS-modelled terrain structures, wave exposure and current speed on the distribution of soft sediment measured using a Sediment Profile Image (SPI) camera. Our analyses showed that the probability of finding soft sediment was best determined by depth, terrain curvature and median current speed at the seafloor. These predictors were used to develop a spatial predictive GIS-model/-map (for parts of Skagerrak, Norway, with a spatial resolution of 25 m × 25 m) of the probability of soft seabed occurrence. 相似文献
3.
由于海岸带的地理条件和海洋动力特性的复杂性以及人类开发活动对海岸带的影响,近岸海域的生态环境系统在空间分布上有很大的变异性.基于现场实测资料,建立系统的空间变异分析模型,对海岸带生态环境空间变化规律进行分析,可以充分了解不同区域的污染特征和变化趋势.应用所构建的空间变异分析模型对渤海湾天津近岸海域的水环境特性进行分析,结合对应年份的入海流量及其变化,分析了天津渤海湾海岸带污染的主因子和区域水环境的分布特征,结果可以对海洋功能区的划分和水环境综合评价结果进行验证和补充. 相似文献
4.
5.
The objectives of this study were to (1) investigate whether the availability of suitable zooplankton prey limits the distribution of the coastal larval areas of pike (Esox lucius) in two archipelago areas of the northern Baltic Sea and (2) compare the availability of zooplankton prey in spring between different types of coastal littoral habitat. According to the results, reed belt habitats formed by Phragmites australis constitute hot spots for zooplankton prey in the coastal ecosystem. During the spring, reed-covered shores of the inner archipelago maintained more than 10 times higher densities of copepods and cladocerans, the preferred prey for larval pike, compared to the other studied shores. Temperature conditions were also most favourable in the reed belt habitat. Thus, the reed belts of the inner and middle archipelago were shown to form the best habitat for larval pike in the coastal area of the northern Baltic Sea, and this was also the only habitat where pike larvae were found. Our results suggest that the poor survival and recruitment of pike in the outer archipelago, however, cannot exclusively be explained by sub-optimal feeding conditions of the larvae. There are also other important factors, presumably connected to the exposure to the open sea, that affect the distribution of the pike larvae. Our results, however, highlight the importance of sheltered coastal reed belt shores as reproduction habitat for spring-spawning fish in the northern Baltic Sea. Further, this study disproves the assumption that the seaweed bladder wrack (Fucus vesiculosus) forms a reproduction habitat for pike in the coastal area. 相似文献
6.
《Journal of Sea Research》2007,57(2-3):198-208
Dover sole (Microstomus pacificus) and rex sole (Glyptocephalus zachirus) are both commercially valuable, long-lived pleuronectids that are distributed widely throughout the North Pacific. While their ecology and life cycle have been described for southern stocks, few investigations have focused on these species at higher latitudes. We synthesized historical research survey data among critical developmental stages to determine the distribution of life cycle stages for both species in the northern Gulf of Alaska (GOA). Bottom trawl survey data from 1953 to 2004 (25 519 trawls) were used to characterize adult distribution during the non-spawning and spawning seasons, ichthyoplankton data from 1972 to 2003 (10 776 tows) were used to determine the spatial and vertical distribution of eggs and larvae, and small-meshed shrimp trawl survey data from 1972 to 2004 (6536 trawls) were used to characterize areas utilized by immature stages. During the non-spawning season, adult Dover sole and rex sole were widely distributed from the inner shelf to outer slope. While both species concentrated on the continental slope to spawn, Dover sole spawning areas were more geographically specific than rex sole. Although spawned in deep water, eggs of both species were found in surface waters near spawning areas. Dover sole larvae did not appear to have an organized migration from offshore spawning grounds toward coastal nursery areas, and our data indicated facultative settling to their juvenile habitat in winter. Rex sole larvae progressively moved cross-shelf toward shore as they grew from April to September, and larvae presumably settled in coastal nursery areas in the autumn. In contrast with studies in the southern end of their range, we found no evidence in the GOA that Dover or rex sole have pelagic larval stages longer than nine months; however, more sampling for large larvae is needed in winter offshore of the continental shelf as well as sampling for newly settled larvae over the shelf to verify an abbreviated pelagic larval stage for both species at the northern end of their range. 相似文献
7.
有色可溶性有机物质(Coloured Dissolved Organic Matter,CDOM)直接影响着海水的光学性质,为水体有机污染物含量遥感反演的基础参数之一。在水色遥感研究领域,一般用440nm波长位置的吸收系数ag(440)来表示其浓度,因而建立ag(440)遥感反演模式,对于掌握相关海域CDOM浓度的空间变化规律及进一步提取其他水环境参数具有重要的作用。利用2013年11月和2014年2月两个航次在珠江口海域现场采集的表观光学量及固有光学量数据,建立了基于HJ-1/CCD卫星传感器的ag(440)遥感反演模型,并应用于珠江口海域,得到该区域2012年1月至2014年6月晴天CDOM浓度空间动态分布图。研究结果表明:(1)现场测定的珠江口海域ag(440)在0.1~0.3m-1,且不同断面ag(440)呈现出一定的规律性变化;(2)利用现场实测数据对遥感模式估算值进行验证,计算出估算值的相对误差为9%,表明所建立模式具有较高的准确率;(3)遥感反演的CDOM空间分布数据与实测数据得到的分布特征基本吻合,整个珠江口及其邻近海域ag(440)的数值范围为0.07~0.31m-1,而且珠江口西部海域ag(440)高于中部和东部海域。 相似文献
8.
Y. Bourls M. Alunno-Bruscia S. Pouvreau G. Tollu D. Leguay C. Arnaud P. Goulletquer S.A.L.M. Kooijman 《Journal of Sea Research》2009,62(2-3):62
A bio-energetic model, based on the DEB theory exists for the Pacific oyster Crassostrea gigas. Pouvreau et al. [Pouvreau, S., Bourles, Y., Lefebvre, S., Gangnery, A., Alunno-Bruscia, M., 2006. Application of a dynamic energy budget model to the Pacific oyster, C. gigas, reared under various environmental conditions. J. Sea Res. 56, 156–167.] successfully applied this model to oysters reared in three environments with no tide and low turbidity, using chlorophyll a concentration as food quantifier. However, the robustness of the oyster-DEB model needs to be validated in varying environments where different food quantifiers reflect the food available for oysters, as is the case in estuaries and most coastal ecosystems. We therefore tested the oyster-DEB model on C. gigas reared in an Atlantic coastal pond from January 2006 to January 2007. The model relies on two forcing variables: seawater temperature and food density monitored through various food quantifiers. Based on the high temperature range measured in this oyster pond (3–30 °C), new boundary values of the temperature tolerance range were estimated both for ingestion and respiration rates. Several food quantifiers were then tested to select the most suitable for explaining the observed growth and reproduction of C. gigas reared in an oyster pond. These were: particulate organic matter and carbon, chlorophyll a concentration and phytoplankton enumeration (expressed in cell number per litre or in cumulative cell biovolume). We conclude that when phytoplankton enumeration was used as food quantifier, the new version of oyster-DEB model presented here reproduced the growth and reproduction of C. gigas very accurately. The next step will be to validate the model under contrasting coastal environmental conditions so as to confirm the accuracy of phytoplankton enumeration as a way of representing the available food that sustains oyster growth. 相似文献
9.
John S. Lively Zena Kaufman Edward J. Carpenter 《Estuarine, Coastal and Shelf Science》1983,16(1):51-68
The phytoplankton ecology of Great South Bay, New York, was studied over a 1-year period. The study area, a large barrier island estuary (coastal lagoon with estuarine circulation), was characterized by high levels of inorganic nutrients, high turbidity and a shallow euphotic zone (<2 m). Net annual primary production by phytoplankton was high—450 g C m?2 year?1—and accounted for approximately 85% of the total ecosystem primary production. Chlorophyll a-specific productivity was dependent on mean photic zone light intensity in areas of the bay <1 m in depth from September 1979 through June 1980; 65–95% of the total light extinction in those areas was attibutable to suspended solids. Nitrogenous nutrient concentration did not limit phytoplankton productivity. Diatom and dinoflagellate cell densities varied greatly over time, while cryptomonad and chlorophyte species were abundant throughtout the year. Chlorophytes of 2–4 μm (‘small forms’) were numerically dominant, and contributed approximately half of the total phytoplankton biomass. Dilution of bay water by intruding ocean water appeared to control the spatial distribution of chlorophyll a on the south side of the bay; in other areas, growth appeared to exceed the rate of dilution by flushing. Waters entrained in eelgrass beds were significantly higher in salinity and mean photic zone light intensity, and had lower phytoplankton standing stock and depth-integrated primary production than control areas; waters in the sediment plume of active clamdigging boats were statistically similar to control areas with respect to water quality and phytoplankton community characteristics. 相似文献
10.
《Progress in Oceanography》2007,72(2-3):117-120
We briefly introduce the different chapters of this special issue which review the current knowledge and understanding of the biology and ecology of Centropages typicus obtained over the last 30 years. The papers are grouped into two major theme areas: the first five papers review behaviour, feeding, metabolism, growth and development, and reproduction, and the four following papers have a regional focus dealing with temporal and spatial distribution in the Mediterranean Sea and in the North Atlantic shelf areas. The findings reviewed in the two groups of papers converge to explain why C. typicus is such a very successful copepod species in these coastal areas. In the different chapters, similarities and differences with congeneric species (C. velificatus, C. hamatus, C. brachiatus, C. chierchiae, C. furcatus, and C. abdominalis) have been explored where these are known. 相似文献
11.
Species distribution maps are needed for ecosystem-based marine management including the development of marine spatial plans. If such maps are based on predictive models then modelling procedures should aim to maximise validation success, and any uncertainty in the predictions needs to be made explicit. We developed a predictive modelling approach to produce robust maps of the distributions of selected marine species at a regional scale. We used 14 years of survey data to map the distributions of plaice, sole and thornback ray in three hydrographic regions comprising parts of the Irish Sea, Celtic Sea and the English Channel with the help of the hybrid technique regression kriging, which combines regression models with geostatistical tools. For each species–region combination we constructed logistic Generalized Linear Models (GLMs) based on presence–absence data using the environmental variables: depth, bottom temperature, bed shear stress and sediment type, as predictors. We selected GLMs using the mean squared error of prediction (MSEP) estimated by cross-validation then conducted a geostatistical analysis of the residuals to incorporate spatial structure in the predictions. In general, we found that species occurrence was positively related to shallow areas, a bed shear stress of between 0 and 1.5 N/m2, and the presence of sandy sediment. Predicted species occurrence probabilities were in good agreement with survey observations. This modelling framework selects environmental models based on predictive ability and considers the effect of spatial autocorrelation on predictions, together with the simultaneous presentation of observations, associated uncertainties, and predictions. The potential benefit of these distribution maps to marine management and planning is discussed. 相似文献
12.
2006—2007年夏、冬季浙东海域叶绿素a分布特征及其环境影响因子 总被引：1，自引：0，他引：1
为更清楚了解浙东海域浮游植物的初级生产力情况,于2006年8月(夏季)和2007年1月(冬季)在浙东海域28°00′～30°00′N、122°00′～127°30′E设置了3条调查断面,共布设25个观测站位,现场采用荧光连续法对叶绿素a进行测定,初步研究了该海域叶绿素a的空间分布特征,并探讨了水体温度、营养盐和浊度对叶绿素a分布的影响。结果表明:夏季,叶绿素a分布趋势为近岸(平均质量浓度为2.01μg/L)>外海(平均质量浓度为0.52μg/L),其主要垂直分布类型为递增型、递减型和单峰型;冬季,叶绿素a分布趋势为外海(平均质量浓度为0.50μg/L)>近岸(平均质量浓度为0.33μg/L),主要垂直分布类型为递增型、均匀型、单峰型和双峰型。夏季调查海域浮游植物叶绿素a平均质量浓度为0.93μg/L,明显高于冬季(0.46μg/L)。温度、营养盐和浊度是影响研究区夏、冬季叶绿素a分布的主要环境因子。 相似文献
13.
Incidental mortality in fisheries is the main at-sea threat albatrosses are facing nowadays. In this study we used remote sensing techniques to model the degree of spatial overlapping between the Black-browed albatross (Thalassarche melanophris) and Argentine fisheries, assuming this as a proxy of risk for albatrosses. Eleven tags were deployed on albatrosses during the non-breeding seasons 2011 and 2012 in the Patagonian Shelf. Their distribution overlapped to different extents with the two coastal trawl, three offshore trawl and one demersal longline fisheries. The overlap index showed highest values with both coastal fleets, followed by the ice-chilling trawl fleet. These intersections were located in the Argentinean–Uruguayan Common Fishing Zone, in coastal areas of the SE of Buenos Aires province, El Rincón estuary and over the shelf break. The analysis of intersections of focal areas from albatrosses and all fisheries allowed the identification of thirty-four fishing management units (1° by 1° grid within the Argentine EEZ) classified as of medium, high or very high conservation priority. Very high priority units were placed between 35 and 38°S in the external mouth of Rio de la Plata, and between 45 and 47°S in neighboring waters East to the hake fishing closure. Although there were possible biases due to the limited number of tracked birds and the locations where albatrosses were captured and instrumented, the information presented in this study provides a comprehensive picture of important areas of overlapping during winter that could be used by the fishery administration to prioritize conservation actions under limited resource scenarios. 相似文献
14.
Aim of this paper is to develop simple tools for mapping — at regional and local scale — coastal areas exposed at flooding risk. A two-step simplified procedure for coastal management purposes is presented and is applied to Emilia Romagna (Italy), whose low and sandy coast faces the relatively mild Northern Adriatic Sea. The procedure is composed by a 1D conceptual model to determine flooding probability along wide coastal stretches and by a more detailed 2D Level II reliability method, that provides local quantitative statistical maps of inland flooding propagation. Qualitative maps obtained by literature approaches and quantitative results of flooding probability along the littoral show a good agreement. A coastal flood state indicator is proposed to rapidly assess coastal hazard. 相似文献
15.
Mara S. Braverman E. Marcelo Acha Domingo A. Gagliardini Martín Rivarossa 《Estuarine, Coastal and Shelf Science》2009,82(4):557-565
Whitemouth croaker (Micropogonias furnieri) larvae obtained and hydrographic data collected in the Rio de la Plata estuary (35°S–56°W) between 1987 and 2000 were used to explore the early life stages spatial and temporal distribution patterns and their relation to oceanographic features. The spatial distribution, restricted to a band in the inner part of the estuary, coincided with the bottom salinity front and the maximum turbidity zone (MTZ, turbidity front). Larvae were present during the warmest months (October through May) within a range of 14–24.5 °C temperature and 0.9–33 salinity. A vertically stratified sampling performed in the region where the largest abundance was found (December 2005 and March 2006) was used to test the hypothesis that larvae retention occurs in the bottom salinity front.The vertically stratified sampling showed larvae throughout the water column with high predominance in the river–estuary transition zone. A positive correlation between abundance and the bottom salinity horizontal gradient was found. The size analysis showed that the largest individuals (>10 mm SL), probably undergoing the settlement process, inhabited near the bottom and that the smallest (<10 mm SL) were present in the whole water column. Length distribution along the front showed no trend.Results support the estuarine retention hypothesis of previous studies on whitemouth croaker gravid females, eggs distribution and outcomes from a numerical simulation model. Retention in the salinity front/MTZ would allow larvae to benefit from food accumulation in the region, the high turbidity level provide shelter against predators and retention in the estuary secure closeness to the main nursery ground. 相似文献
16.
To investigate feeding habits of juvenile flounder (Platichthys flesus) and turbot (Psetta maxima) in relation to habitat characteristics a field survey with push net sampling was conducted in nursery areas with different ecological characteristics in the northern Baltic proper. Sampling sites were stratified to cover several different habitat types defined by substrate and wave exposure. Apart from flatfishes and epifauna, samples of macrofauna, meiofauna and hyperbenthic planktons were collected from each site together with data on vegetation, depth, salinity, temperature and turbidity. The diet differed between species where flounder diet was dominated by chironomids, copepods and oligochaetes while turbot apart from chironomids had a high incidence of amphipods, gobies and mysids. In both species there was a shift in diet with size, although this shift was influenced by the habitat. Among the environmental variables investigated, wave exposure was found to significantly influence flounder diet. Food preference in the most exposed areas was dominated by oligochaetes and copepods instead of chironomids, which dominated in sheltered areas. This study shows that habitat characteristics can have a major influence on feeding habits of juvenile flatfish. 相似文献
17.
Hendrik Jan van der Woerd Anouk Blauw Louis Peperzak Reinold Pasterkamp Steef Peters 《Journal of Sea Research》2011,65(2):195-204
Phaeocystis blooms in the Southern Bight of the North Sea may cause damage to the aquatic ecosystem and to commercial mussel cultures at the entrance of the Oosterschelde estuary. In this paper the potential for early detection of Phaeocystis blooms in Dutch coastal waters is studied, using a combination of field data, satellite observations and hydrodynamic- and biological modelling. For the spring bloom period in the year 2003 MERIS chlorophyll-a maps, derived with the HYDROPT algorithm for coastal waters, were compared to in-situ measurements at stations off the coast in de Voordelta and the results of the GEM biogeochemical model.The analysis shows that the spatial and temporal variability in Phaeocystis abundance and total biomass (expressed by the Chl-a concentration) during spring is large. It is confirmed that blooms may develop off shore and show a tendency to accumulate within 10 km from the coastline, giving rise to rapid biomass accumulation at the mouth of the multiple estuaries in the Voordelta. Based on the outcome of this study an early warning system is proposed that notifies local water managers and shellfish growers for potentially harmful Phaeocystis bloom formation. 相似文献
18.
《Oceanologica Acta》1998,21(1):87-93
A space-time approach is adopted in an attempt to understand the long-term influence of currents on the spatial pattern distribution of zooplankton, ichthyoplankton, and fish larvae communities in the Bay of Campeche, Mexico.The analysis is performed using results of a hydrodynamic numerical model, and zooplankton and ichthyoplankton abundances.Three fish larvae communities were identified in the Bay, on the basis of its physiography, i.e.: “neritic fluvio lagoon influence”, “neritic” and “oceanic” communities.A cyclonic eddy is formed in the Bay and drifts westward, facilitating transport and distribution of planktonic organisms. The eddy provides larvae transport from oceanic areas to the coastal areas and vice-versa. The seasonal distribution of fish larvae is highly influenced by the position of the eddy.The biomass pattern and fish larvae density observed in the coastal area off the Grijalva-Usumacinta delta are governed by the coastal front. 相似文献
19.
Traditionally, it was assumed that major spawning activity of Illex argentinus occurs in discrete pulses along the outer-shelf/slope off Argentina/southern Brazil during late-fall/winter and that early life stages develop near the Brazil–Malvinas Confluence (BMC). However, a novel hypothesis of the population structuring of the species was proposed that states that coastal waters may be important as spawning and feeding grounds. Here, we analyzed the spatial distribution of Illex argentinus inside San Matias Gulf based on the position of the CPUE of jiggers in order to improve the knowledge of the population structuring in coastal regions. Squids were mainly concentrated on the northern region of the gulf where favorable oceanographic conditions (e.g. water stratification, chlorophyll-a concentration peaks) to feeding and spawning are present. These results provided empirical evidences that individuals of I. argentinus use Argentinean coastal waters, particularly San Matias Gulf, as permanent feeding and spawning grounds which supports the new hypothesis. 相似文献