The influence of equilibrium partitioning, biotransformation and lipid depletion on patterns of chlorinated biphenyls in marine mammals     

Jan P. Boon  Ina Oostingh  M. Theo  J. Hillebrand 《Marine environmental research》1995,39(1-4)

  相似文献   

Histoire structurale du golfe de gascogne/structural history of the bay of Biscay: J. Debyser,X. Le Pichon and L. Montadert (editors). Editions Technip,Paris, 1971, 2 vols., Fr.Francs 180.00     

P.G.Van Dongen 《Marine Geology》1972

  相似文献   

Linear evolution of a shoreface nourishment     

S. Van Leeuwen  N. Dodd  D. Calvete  A. Falqués 《Coastal Engineering》2007

The morphological evolution of a shoreface nourishment is investigated by interpreting the nourishment as a linear perturbation of the natural system. The nourishment is projected onto the subset of linear eigenmodes with negative growth rates of the morphodynamical system. The evolution of these linear modes then determines the temporal behaviour of the shoreface nourishment. The method is presented, and results are shown for shoreface nourishments of different length scales on a straight coast and subject to normal incidence. Shoreface nourishments are represented by their expansions according to the projection method on a 1:50 plane beach profile. All nourishments are shown primarily to be diffusive features, with long scale nourishments diffusing more slowly than shorter length scale nourishments. Long scale nourishments also exhibit a shoreward movement during their decay. This all indicates that long length scale nourishments may be more beneficial in coastal engineering projects. This study is a first step towards nonlinear projection to study shoreface nourishment behaviour.  相似文献   

Dissolved aluminium in the Weddell-Scotia Confluence and effect of Al on the dissolution kinetics of biogenic silica   总被引：1，自引：0，他引：1  

A.J. Van Bennekom  A.G.J. Buma  R.F. Nolting 《Marine Chemistry》1991,35(1-4)

In the Scotia and Weddell Seas the concentration of dissolved Al was 1–1.5 nM in ice-free surface waters, up to 3 nM in ice-covered waters and about 2.6 nM in bottom waters. The solubility and the dissolution rate of diatomaceous silica, obtained from net samples and from incubations in the presence or absence of dissolved Al, were inversely related to solid-phase Al/Si ratios. At in situ temperatures, dissolution rates for Antarctic diatoms are higher than those for diatoms from temperate regions. Effects on distribution patterns of silicic acid in the Weddell Sea are discussed.  相似文献   

The Vema fracture zone and the tectonics of transverse shear zones in oceanic crustal plates     

Tjeerd H. Van Andel  Richard P. Von Herzen  J. D. Phillips 《Marine Geophysical Researches》1971,1(3):261-283

At 11°N latitude, the Mid-Atlantic ridge is offset 300 km by the Vema fracture zone. Between the ridge offset, the fracture consists of an elongate, parallelogram-shaped trough bordered on the north and south by narrow, high walls. The W-E trending valley floor is segmented by basement ridges and troughs which trend W10°N and are deeply buried by sediment. Uniform high heat flow characterizes the valley area. Seismically inactive valleys south of the Vema fracture, also trending W10°N, are interpreted as relict fracture zones. We explain the high heat flow and the shape of the Vema fracture as the results of secondary sea-floor spreading produced by a reorientation of the direction of sea-floor spreading from W10°N to west-east. This reorientation probably began approximately 10 million years ago. Rapid filling of the fracture valley by turbidites from the Demerara Abyssal plain took place during the last million years.The large amount of differential uplift in the Vema fracture is not explained by the reorientation model. Since the spreading rate across the valley is small compared to that across the ridge crest, we suggest that it takes place by intrusion of very thin dikes that cool rapidly and hence have high viscosity. Upwelling in the fracture valley will thus result in cosiderable loss of hydraulic head, according to models by Sleep and Biehler (1970), and recovery of the lost head could produce valley walls higher than the adjacent ridge crest. We further postulate that the spreading takes place along the edges of the fracture zone rather than in the center. This would account for the uniform distribution of heat flow along the fracture valley and for the lack of disturbance of the valley fill. As a consequence, a median ridge should form in the center, where head loss is compensated in the older crust; such a median ridge may be present. The width of the valley should be a function of the angle and time of reorientation, and of the spreading rate; the width so obtained for the Vema fracture is in accordance with the observed width. If this model is correct, the narrowness of the valley walls implies a thin lithosphere of very limited horizontal strength.  相似文献   

Erratum to “Mangroves mitigate tsunami damage: A further response” [Estuar. Coast. Shelf Sci. 69 (1–2) (2006) 1–3]     

Jan E. Vermaat  Udomluck Thampanya 《Estuarine, Coastal and Shelf Science》2007,75(4)

  相似文献   

Infection of Baltic herring (Clupea harengus membras) with Anisakis simplex larvae, 1992-1999: a statistical analysis using generalized linear models     

Podolska  Magdalena; Horbowy  Jan 《ICES Journal of Marine Science》2003,60(1):85-93

  相似文献   

Age determination of Baltic herring from whole otoliths and from neutral red stained otolith cross sections   总被引：2，自引：1，他引：2  

Peltonen  Heikki; Raitaniemi  Jari; Parmanne  Raimo; Eklund  Jan; Nyberg  Kari; Halling  Folke 《ICES Journal of Marine Science》2002,59(2):323-332

  相似文献   

Bioaccumulation and biomarkers in the sea star Asterias rubens (Echinodermata: Asteroidea): a North Sea field study     

den Besten PJ  Valk S  van Weerlee E  Nolting RF  Postma JF  Everaarts JM 《Marine environmental research》2001,51(4):365-387

During two North Sea field trips in March 1995 and September 1996 sea stars, Asterias rubens, were collected at various stations along pollution gradients in order to study the relation between biochemical markers and levels of accumulated contaminants. Biomarkers measured were: cytochrome P450 level, benzo[a]pyrene hydroxylase (BPH) activity, acetylcholinesterase (AChE) activity and DNA integrity. Accumulation levels of heavy metals, polychlorinated biphenyls, organochlorine pesticides and polycyclic aromatic hydrocarbons (PAHs) in the pyloric caeca of sea stars indicate different pollution gradients, influenced by rivers in The Netherlands, UK and Germany. For some contaminants, especially PAHs, relatively high levels were found in the central part of the North Sea (Dogger Bank). On the basis of multivariate statistics, stations near the mouth of the Elbe and the Rhine/Meuse were shown to have different patterns of biomarker responses. Sea stars from stations in coastal zones showed relatively high levels of cytochrome P450 and 'P418', another haemoprotein that is present in most marine invertebrates. The station nearest to the Elbe Estuary showed the lowest BPH and AChE activity. DNA integrity was lower especially in stations near the Dutch coast and in a station near the Tees/Tyne estuaries. Using these biomarkers as early warning signals of exposure and/or adverse effects, this type of monitoring can be used also in the future to study the spatial and temporal trends in the quality of coastal waters.  相似文献   

Possible effects of climate change on estuarine nutrient fluxes: a case study in the highly nutrified Schelde estuary (Belgium, The Netherlands)     

Eric Struyf  Stefan Van Damme  Patrick Meire 《Estuarine, Coastal and Shelf Science》2004,60(4):649-661

Global change models predict effects of climate change on hydrological regimes at the continental scale in Europe. The aim of this study was to gain a better understanding of the possible effect of changing external forcing conditions on the functioning of estuarine ecosystems. In densely populated areas, anthropogenic nutrient enrichment and consequent alteration of nutrient biogeochemical cycles have already had a big impact on these ecosystems. The average yearly discharge of the upper Schelde estuary increased nearly threefold over the period 1996–2000, from 28 m³ s⁻¹ in 1996 to 73 m³ s⁻¹ in 2000. The continuously rising discharge conditions over the five-year period were used as a reference situation for possible future effects of climate on ecological functioning through increase of discharge. At high discharges, nutrient (NH₄⁺, NO₃⁻, dissolved silica and PO₄³⁻) concentrations in the tidal fresh- and brackish water showed a decrease of up to 50% while total discharged nutrient loadings increased up to 100%. Opposite effects of increasing discharge on NH₄⁺, NO₃⁻ and dissolved silica concentrations in summer and winter, resulted in the flattening out of seasonal cycles for these nutrients. Under high discharge conditions, silica uptake by diatom communities was lowered. Dissolved silica loadings to the coastal area increased concurrently with total silica loadings upstream. Salt intrusion to the marine parts of the estuary decreased. This resulted in a downstream shift of the salinity gradient, with lower salinity observed near the mouth. As a result, TDIN, NO₃⁻ and dissolved silica concentrations doubled at the mouth of the estuary.  相似文献