|
|
|
| Registros recuperados: 28 | |
|
|
| Pastor, L.; Cathalot, C.; Deflandre, B.; Viollier, E.; Soetaert, K.; Meysman, F. J. R.; Ulses, C.; Metzger, E.; Rabouille, C.. |
| In situ oxygen microprofiles, sediment organic carbon content, and pore-water concentrations of nitrate, ammonium, iron, manganese, and sulfides obtained in sediments from the Rhone River prodelta and its adjacent continental shelf were used to constrain a numerical diagenetic model. Results showed that (1) the organic matter from the Rhone River is composed of a fraction of fresh material associated to high first-order degradation rate constants (11-33 yr(-1)); (2) the burial efficiency (burial/input ratio) in the Rh boolean AND one prodelta (within 3 km of the river outlet) can be up to 80 %, and decreases to similar to 20% on the adjacent continental shelf 10-15 km further offshore; (3) there is a large contribution of anoxic processes to total... |
| Tipo: Text |
|
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00303/41423/40614.pdf |
| |
|
|
| Soetaert, K.; Heip, C.H.R.. |
| The nematode community structure of several shelf break and deep-sea stations in the North Atlantic and the Mediterranean is compared using data from the literature. Samples from 2 Mediterranean deep-sea canyons have a unique fauna of predatory and scavenging nematodes (e.g. <i>Synonchiella, Halichoanolaimus, Gammanema</i>) which comprise some 20 to 30% of the community, while some of the typical deep-sea genera (<i>Theristus, Acantholaimus</i>) are only marginally present. The nematode generic composition of the other sites reveals a gentle transition from the shelf break (Bay of Biscay; Mediterranean) over the slope (Mediterranean) towards the continental rise, abyssal plain and hadal depths (Bay of Biscay, Puerto Rico Trench,... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1995 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8457 |
| |
|
|
| Soetaert, K.; Herman, P.M.J.; Middelburg, J.J.; Heip, C.H.R.; deStigter, H.S.; van Weering, T.C.E.; Epping, E.; Helder, W.. |
| The influence of sediment mixing on activity versus depth profiles of the radionuclide <sup>210</sup>Pb in the upper 20 cm of the sediments has been investigated along a depth transect (208 m-4500 m, 17 stations) in the OMEX study area (Goban Spur, NE Atlantic Ocean). A hierarchical family of bioturbation/nonlocal exchange models was derived. Each member of the hierarchy includes all processes of the previous model, and adds a one- or two-parameter process. The significance of the additional parameters is tested using a one-tailed <i>F</i>-test. It was found that (1) in five cases there is a significant improvement when direct injection of part of the flux into deeper sediment layers (nonlocal exchange) is added to the diffusive... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chemical kinetics Continental margins Diffusion Lead 210 Modelling Sediment mixing ANE; Goban Spur. |
| Ano: 1996 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8450 |
| |
|
|
| Soetaert, K.; Heip, C.H.R.. |
| The nematode assemblages along a deep-sea transect in the Mediterranean are composed of individuals that are as small as those found in other areas at much greater depth. This may be related to the low surface primary production since chloroplastic pigment equivalent (CPE) values in the sediments are low as well. A significant decrease of both nematode size and sedimentary CPE values with increasing water depth was found. At all water depths average nematode length increases with depth in the sediment (0-2 cm) due to the decreasing abundance of smaller nematodes. |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1989 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8470 |
| |
|
| |
|
|
| Soetaert, K.; Heip, C.H.R.; Vincx, M.. |
| The diversity of the nematode assemblages along a Mediterranean transect off Calvi, Corsica, Mediterranean Sea (depth range 160 to 1220 m) was very high. There was no clear trend in species diversity with station depth, and diversity at the station located on the continental shelf was not markedly lower than that at the deep-sea stations. However, diversity decreased with increasing depth into the sediment. As with the macrofauna, nematode assemblages in the Mediterranean is explained by a slight dominance of some species, while no species are dominant in the Bay of Biscay. Generic (between-genus) diversity was much higher than the average species diversity within genera, indicating that the high overall species diversity was not caused by large numbers of... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1991 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2892 |
| |
|
|
| Soetaert, K.; Vincx, M.; Wittoeck, J.; Tulkens, M.. |
| Meiofauna from the intertidal zone of five European estuaries (Ems, Westerschelde, Somme, Gironde, Tagus) was investigated. Samples represented a cross section of various benthic habitats from near-freshwater to marine, from pure silts to fine-sandy bottoms. The meiobenthic community comprised everywhere a fauna strongly dominated by nematodes, with meiobenthic density increasing with increasing salinity. The Ems differed from the other estuaries due to the presence of a well developed community of Copepods, Gastrotrichs, large Ciliates and/or soft-shelled Foraminiferans in some sites. The Westerschelde stood out due to the near-absence of harpacticoid copepods and, as in the Tagus, the lower meiobenthic densities in the marine part of the estuary. For... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Estuaries Intertidal environment Marine invertebrates Meiobenthos Population density Species diversity Copepoda [copepods] Gastrotricha Nematoda [Nematodes] Polychaeta [Bristle worms] ANE; Ems Estuary ANE; France; Gironde Estuary ANE; France; Picardie; Somme Estuary ANE; Netherlands; Westerschelde Portugal; Tagus R.. |
| Ano: 1995 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8456 |
| |
|
| |
|
|
| Soetaert, K.; Herman, P.M.J.; Middelburg, J.J.; Heip, C.H.R.. |
| We test whether organic matter degradability, mixing activity, and total sediment mineralization can be estimated by inversion of a coupled nonlinear numerical steady-state diagenetic model. We use a single data set comprising oxygen, nitrate, ammonium and organic carbon versus depth profiles from a slope station in the Goban Spur area (1034 m, Northeast Atlantic). Based on an extensive sensitivity analysis, it appears that (1) when using all data, the total mineralization rates can be determined with reasonable precision; bioturbation and degradability are less well constrained and (2) total mineralization rates can be determined based on nitrate and oxygen profiles only; estimates of organic matter mixing rates and degradability are refined when... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1998 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8426 |
| |
|
|
| Soetaert, K.; Heip, C.H.R.; Vincx, M.. |
| Meiobenthos densities (excluding hard-shelled Foraminiferans) were compared along a Mediterranean deep-sea transect off Calvi (Corsica) and in an adjacent canyon. Chloroplastic Pigment Equivalent values (CPE) provided an estimate of the amount of primary production reaching the bottom.The stations along the transect were characterized by a low CPE content of the sediment, decreasing with increasing station depth. CPE values in the canyon were much higher, which probably resulted from import of material from the adjacent bay of Calvi. Similarly, meiobenthos densities along the transect were much lower than at comparable depths along the canyon.Meiobenthos density was significantly and positively correlated with CPE values.Nematodes were the most abundant... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1991 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2893 |
| |
|
|
| Vanaverbeke, J.; Soetaert, K.; Heip, C.H.R.; Vanreusel, A.. |
| The metazoan meiobenthos along the continental slope of the Goban Spur (NE Atlantic) was studied in the framework of the OMEX-programme (EC-MAST II). Meiobenthic densities, the vertical distribution of the meiobenthos in the sediment, and the biomass and generic composition of the dominant group, the nematodes, were investigated at different water depths. The meiobenthic communities along the depth gradient of the continental slope followed the usual trends: the communities were dominated by nematodes, and meiobenthic densities, total nematode biomass, and mean individual nematode weight decreased with increasing water depth. The shelf station had significantly higher densities, nematode biomass and mean individual weight than the deeper stations. The... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1997 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=5650 |
| |
|
|
| Heip, C.H.R.; Goosen, N.K.; Herman, P.M.J.; Kromkamp, J.; Middelburg, J.J.; Soetaert, K.. |
| The question is reviewed whether a balance exists between production and consumption of biological particles in temperate tidal estuaries and what the relationships are between the magnitude of production and consumption processes and system carbon metabolism. The production terms considered are primary production by phytoplankton, microphytobenthos, macroalgae and vascular plants and the chemoautotrophic production, mainly by nitrifying bacteria. The consumption terms are generalized by considering pelagic and benthic mineralization, but major consumer compartments, heterotrophic bacteria, zooplankton, meiobenthos, and macrobenthos are considered in detail. The proposition that estuaries are heterotrophic systems, and become more so when nutrient inputs... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1995 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8311 |
| |
|
|
| Soetaert, K.; Vincx, M.; Heip, C.H.R.. |
| Nematode assemblages along a Mediterranean depth transect (160-1220 m) and vertically in the sediment were investigated. The station at the edge of the continental shelf (160 m) was distinctly different from those situated on the continental slope (280-1220 m). On the slope, nematode communities in the upper centimetre differed significantly from communities in the deeper sediment layers, which were dominated by fewer and larger species. Vertical segregation could be a factor explaining the coexistence of several species belonging to the genus <i>Sabatieria</i>, with larger species penetrating deeper into the sediment. Clear differences in buccal morphology suggest food resource partitioning as the dominant factor promoting coexistence of... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1995 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8452 |
| |
|
|
| Soetaert, K.; Van Rijswijk, P.. |
| The invertebrate zooplankton fauna of the Westerschelde (Belgium and The Netherlands) was investigated during 2 yr by means of monthly samples along a salinity gradient. Copepods were usually the most abundant holoplanktonic metazoans except in the freshwater zone where Rotifera were most numerous. The combination of a classification technique and an ordination-regression technique proved to be a valuable tool for the analysis of such an extensive data set. The presence of 4 groups was established, representing spatially distinct populations but with temporally shifting boundaries. Few zooplankton species were truly estuarine in their distribution, but many were derived from nearby coastal waters. This intrusion of marine species started in spring,... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1993 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8467 |
| |
|
|
| Soetaert, K.; Herman, P.M.J.; Kromkamp, J.. |
| Net phytoplankton productivity in the Westerschelde, a relatively deep. highly turbid and eutrophic estuary in the Southwest Netherlands, was examined by means of a 13-compartment dynamic simulation model. The description of the light-Iimited primary production was based on the model of Eilers and Peeters (1988. <i>Ecol. Model.</i>, 42, 185-198). This light limitation was parameterized to the different model compartments by integrating the Eilers-Peeters model over a day and over depth taking into account the morphology of the Westerschelde compartments, the daily fluctuating light regime and characteristics of the photosynthesis-Iight curves of the phytoplankton community. The availability of light to the phytoplankters limited primary... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1994 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8464 |
| |
|
|
| Soetaert, K.; Herman, P.M.J.; Middelburg, J.J.. |
| We present a numerical model of sedimentary early diagenetic processes that includes oxic and anoxic mineralization. The model belongs to the new wave of early diagenesis models that account for depth-dependent bioturbation and porosity profiles; it can be used both for calculating steady-state conditions and transient simulation. It was developed to reproduce the cycling of carbon, oxygen, and nitrogen along the ocean margin; it resolves the sediment-depth profiles of carbon, oxygen, nitrate, ammonium, and other reduced substances. Organic carbon is modeled as two degradable fractions with different first-order degradation rates and nitrogen:carbon ratios, to account for the decreasing reactivity and N/C ratio of the organic matter with depth into the... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1996 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8408 |
| |
|
|
| Soetaert, K.; Herman, P.M.J.; Middelburg, J.J.. |
| We present a dynamic, numerical model of early diagenetic processes that can be used to examine the response of different organic carbon mineralization pathways, concentration vs. depth profiles, and the resultant fluxes to seasonally varying carbon deposition. We show that there can be substantial temporal variability in sediment-water fluxes as well as in the relative contribution of different organic carbon mineralization pathways and oxygen consumption processes in deep-sea sediments. The timing and amplitude of the sediment response are most sensitive to the reactivity of the organic matter. We show that the fluxes of dissolved substances can be approximated by assuming that these constituents are at steady state with the carbon profiles. The model is... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1996 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8444 |
| |
|
|
| Middelburg, J.J.; Soetaert, K.; Herman, P.M.J.; Heip, C.H.R.. |
| The rate and factors controlling denitrification in marine sediments have been investigated using a prognostic diagenetic model. The model is forced with observed carbon fluxes. bioturbation and sedimentation rates, and bottom water conditions. It can reproduce rates of aerobic mineralization, denitrification, and fluxes of oxygen, nitrate, and ammonium. The globally integrated rate of denitrification is estimated by this model to be about 230-285 Tg N yr<sup>-1</sup>, with about 100 Tg N yr<sup>-1</sup> occurring in shelf sediments. This estimate is significantly higher than literature estimates (12-89 Tg N yr<sup>-1</sup>), mainly because of a proposed upward revision of denitrification rates in slope and deep-sea... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1996 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8415 |
| |
|
| |
| Registros recuperados: 28 | |
|
|
|
