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1. Abstracts of Other Local Studies and Phytogeographical Contributions

Author

Hoffmann, Lucien, Lange-Bertalot, Horst, Bovin, Kathleen, Vanhoutte, Koenraad, Hodgson, D., Vyverman, Wim, Sabbe, Koen, Cambra, Jaume, Dell'uomo, Antonio, Santoni, Monica, Tackx, M., Gichuki, J., Symoens, J. J., Taton, A., Grubisic, S., Wilmotte, A., Urrutia, R., Cisternas, M., Torres, L., Cruces, F., Araneda, A., and Debels, P.

Published
2000
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6. Zooplankton distribution and community structure as a function of environmental variables in the Niger River and its tributaries in Niger.

Author

Souley Adamou, H, Alhou, B, Tackx, M, and Azémar, F

Subjects
ZOOPLANKTON, COPEPODA, ROTIFERA, FISH communities, CHLOROPHYLL, CRUSTACEA
Abstract

The Niger River and its main tributaries (Sirba, Tapoa and Mékrou) in Niger were sampled during high and low water flow with the objectives of (1) comparing the taxonomic structure, diversity and abundance of the zooplankton community (rotifers, copepods, crustaceans) along the river and (2) determining which environmental or biological factors influence the distribution of the zooplankton communities most strongly. The impact of the tributaries at high-flow was also evaluated. Rotifers (32 taxa) were the most abundant and diverse followed by Cladocerans (13 taxa) and Copepods (three taxa). The mean number of taxa (16.5 and 17.6, respectively), the Shannon-Weaver diversity index (2.7 and 2.8, respectively) and the evenness (0.7 and 0.7, respectively) did not vary significantly between the high- or low-flow periods, or along the length of the Niger River and its tributaries. The mean zooplankton abundance was highest during low-flow periods (40 × 103 ± 45 × 103 ind. m−3) but showed no specific spatial pattern. During high-flow sampling, the mean zooplankton abundance (3 × 103 ± 2 × 103 ind. m–3) increased progressively downstream. RDA analysis showed that rotifers are associated with high conductivity and NO2− concentrations, copepods with chlorophyll a, while cladocerans were abundant when conductivity, chlorophyll a and NO2− concentrations were low. [ABSTRACT FROM AUTHOR]

Published
2023
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11. Distribution of phthalates in Marseille Bay (NW Mediterranean Sea)

Author

Le Coz, M., Chambord, S., Souissi, S., Meire, P., Ovaert, J., Buffan-Dubau, E., Prygiel, J., Azemar, F., Sossou, A.C., Lamothe, S., Julien, F., Ouddane, B., Net, Sopheak, Dumoulin, D., Tackx, M., Institut méditerranéen d'océanologie ( MIO ), Institut de Recherche pour le Développement ( IRD ) -Aix Marseille Université ( AMU ) -Université de Toulon ( UTLN ) -Centre National de la Recherche Scientifique ( CNRS ), Dept Sci, UMR Inserm, University of The French West Indies, Institut Français de Recherche pour l'Exploitation de la Mer ( IFREMER ), Laboratoire Environnement Ressources Provence - Azur - Corse, Laboratoire de Spectrochimie Infrarouge et Raman - UMR 8516 ( LASIR ), Université de Lille-Centre National de la Recherche Scientifique ( CNRS ), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), Laboratoire Environnement Ressources Provence Azur Corse (LERPAC), LITTORAL (LITTORAL), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Université du Littoral Côte d'Opale-Université de Lille-Centre National de la Recherche Scientifique (CNRS), University of Antwerp (UA), Laboratoire de Spectrochimie Infrarouge et Raman - UMR 8516 (LASIR), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Biotechnologie et Chimie Marines (LBCM), Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université de Bretagne Sud (UBS), and Université de Lille, Sciences et Technologies

Subjects
[ SDU.OCEAN ] Sciences of the Universe [physics]/Ocean, Atmosphere, Environmental Engineering, 010504 meteorology & atmospheric sciences, 010501 environmental sciences, Diethyl phthalate, 01 natural sciences, chemistry.chemical_compound, Water column, Phthalates, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Dissolved organic carbon, Environmental Chemistry, Seawater, Dissolved organic matter, Organic matter, DMP, 14. Life underwater, Endocrine disruptors, Waste Management and Disposal, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, ComputingMilieux_MISCELLANEOUS, seawater, 0105 earth and related environmental sciences, chemistry.chemical_classification, DEHP, Phthalate, dissolved organic matter, [SDE.ES]Environmental Sciences/Environmental and Society, Pollution, endocrine disruptors, chemistry, 13. Climate action, Environmental chemistry, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay, Dimethyl phthalate
Abstract

International audience; Phthalic Acid Esters (PAEs) are a group of emerging organic contaminants that have become a serious issue because of their ubiquitous presence and hazardous impact on the marine environment worldwide. Seawater samples were collected monthly from December 2013 to November 2014 in the northwestern Mediterranean Sea (Marseille Bay). The samples were analyzed for dissolved organic carbon (DOC) as well as the molecular distribution of dissolved PAEs by using solid phase extraction followed by gas chromatography and mass spectrom-etry (GC/MS) analyses. The results demonstrated the occurrence of six PAEs, including dimethyl phthalate (DMP), diethyl phthalate (DEP), di-isobutyl phthalate (DiBP), din -butyl phthalate (DnBP), benzylbutyl phthalate (BzBP) and diethylhexyl phthalate (DEHP), with total concentrations ranging from 130 to 1330 ng L −1 (av. 522 ng L −1). In Marseille Bay, the highest concentrations were detected in the bottom water from June to November 2014 and in the whole water column during the winter mixing period. This result suggests that resuspension of PAE-rich sediment, in relation to the accumulation of plastic debris above the seabed, or the higher degradation rate in the upper layer of the water column, plays a significant role in the PAE dynamics in coastal water. DEHP was the most abundant PAE in all of the surface samples and the summer bottom samples, followed by DiBP and DnBP, which also represent the largest fractions in the other bottom samples.

Published
2018

23. Are zooplankton communities structured by taxa ecological niches or by hydrological features?

Author

Le Coz, M., primary, Chambord, S., additional, Souissi, S., additional, Meire, P., additional, Ovaert, J., additional, Buffan-Dubau, E., additional, Prygiel, J., additional, Azémar, F., additional, Sossou, A.C., additional, Lamothe, S., additional, Julien, F., additional, Ouddane, B., additional, Net, S., additional, Dumoulin, D., additional, and Tackx, M., additional

Published
2018
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24. Test of some ecological concepts on the longitudinal distribution of zooplankton along a lowland water course

Author

Le Coz, M., Chambord, S., Meire, P., Maris, T., Azémar, F., Ovaert, J., Buffan-Dubau, E., Kromkamp, J.C., Sossou, A.C., Prygiel, J., Spronk, G., Lamothe, S., Ouddane, B., Rabodonirina, S., Net, S., Dumoulin, D., Peene, J., Souissi, S., Tackx, M., Le Coz, M., Chambord, S., Meire, P., Maris, T., Azémar, F., Ovaert, J., Buffan-Dubau, E., Kromkamp, J.C., Sossou, A.C., Prygiel, J., Spronk, G., Lamothe, S., Ouddane, B., Rabodonirina, S., Net, S., Dumoulin, D., Peene, J., Souissi, S., and Tackx, M.

Abstract

The distribution of zooplankton communities from the source to the mouth of a lowland water course, the Scheldt, was used to test some concepts on the longitudinal distribution of organisms along both estuarine (Remane’s diversity concept) and riverine reaches (River Continuum Concept (RCC), Riverine Ecosystem Synthesis (RES)). Substantial zooplankton densities were found in both April and June samples all along the water course, and not only in the lower reaches as suggested by the RCC. Based on the zooplankton communities, and using hierarchical classifications and Generalized Linear Model, several successive zones influenced by different physical and chemical variables and trophic conditions could be distinguished along the Scheldt, in agreement with the RES model: the non-tidal riverine, the tidal freshwater, the tidal salinity gradient, and the marine zones. Over the entire freshwater reach, rotifers were numerically dominant during both samplings; crustaceans became more abundant in June than in April, specifically in the downstream reaches. Highest total zooplankton abundance and diversity were found in the tidal freshwater reach, lowest in the brackish water reach, in accordance with Remane’s concept. An influence of the tributaries on zooplankton communities is suggested, directly by import or dilution of zooplankton communities or through changing environmental conditions.

Published
2017

27. Spatial distribution of zooplankton communities in the Scheldt Continuum and relation with the Water Frame Directive

Author

Le Coz, Martine, Dumoulin, D., Chambord, S., Ovaert, J., Net-David, S., Sossou, C., Azemar, F., Fernandez, R., Ouddane, B., Prygiel, J., Meire, P., Souissi, S., Tackx, M., Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de Biotechnologie et Chimie Marines (LBCM), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Antwerp (UA), Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université de Toulouse (UT)

Subjects
[CHIM.ANAL]Chemical Sciences/Analytical chemistry, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Published
2015

28. Mesozooplankton affinities in a recovering freshwater estuary

Author

Chambord, S., Maris, T., Colas, F., van Engeland, T., Sossou, A.-C., Azémar, F., Le Coz, M., Cox, T., Buisson, L., Souissi, S., Meire, P., Tackx, M., Chambord, S., Maris, T., Colas, F., van Engeland, T., Sossou, A.-C., Azémar, F., Le Coz, M., Cox, T., Buisson, L., Souissi, S., Meire, P., and Tackx, M.

Abstract

Water quality of the Scheldt estuary (Belgium/The Netherlands) has considerably improved in recent years, especially in the upstream, freshwater reaches. Within the zooplankton community, the copepod Eurytemora affinis, typically abundant in brackish water and quasi-absent from freshwater before 2007, has since substantially developed in the latter, where it now represents 90% of the crustacean mesozooplankton community. Simultaneously, cyclopoid copepod abundance has greatly decreased, while cladoceran abundance did not change. The study aim was: 1) to verify if the zooplankton community described for the period 2007–2009 by Mialet et al. (2011) has stabilized until present, and 2) to look for the environmental conditions favouring E. affinis development and causing changes in the upstream freshwater zooplankton community. The 2002–2012 temporal evolution of the zooplankton distribution at three stations in the upstream freshwater Scheldt estuary was analyzed. Water quality remained better after 2007 than before, and some factors revealed continuous improvement in annual mean concentrations (e.g. increase in O2, decrease in BOD5 and NH4-N concentration). The increase in oxygen and the decrease in NH4-N concentration, together with low discharge during summer were the main environmental factors explaining the development and timing of E. affinis in the upstream freshwater reach. In this reach, E. affinis maximal abundance is shifted to higher temperatures (summer) compared to its typical maximum spring abundance peak in the brackish zone of the Scheldt estuary and in most temperate estuaries. The changes in zooplankton community followed a temporal and spatial gradient induced by the spatio-temporal evolution of water quality improvement. The most downstream station (3) allowed E. affinis development (oxygen concentration > 4 mg L-1; NH4-N concentration < 2 mg L-1, d

Published
2016

33. Tidal exchange between a freshwater tidal marsh and an impacted extuary: the Scheldt estuary, Belgium

Author

Van Damme, S., Dehairs, F., Tackx, M., Beauchard, O., Struyf, E., Gribsholt, B., Van Cleemput, O., Meire, P., University of Antwerp (UA), Analytical, Environmental and Geo- Chemistry, Vrije Universiteit Brussel (VUB), Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Netherlands Institute of Ecology, Laboratory of Applied Physical Chemistry, Universiteit Gent = Ghent University [Belgium] (UGENT), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2009

34. New occurrence of Lecane decipiens (Murray, 1913) and some other alien rotifers in the Schelde estuary (Belgium)

Author

Frédéric Azémar, Damme, S., Meire, P., Tackx, M., Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Ecosystem Management Research Group (ECOBE), University of Antwerp (UA)-ECOBE, Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Universiteit Antwerpen - UA (BELGIUM), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Ecosystem management research group - ECOBE (Wilrijk, Belgium), and University of Antwerp (UA)

Subjects
[SDV.EE]Life Sciences [q-bio]/Ecology, environment, Ecologie, Environnement, Belgium, Schelde R, Lecane decipiens, Brachionus variabilis, Introduced species, Lecane decipiens (Murray, 1913), Schelde estuary, Keratella tropica
Abstract

Three alien rotifers were found in the Schelde estuary in spring and summer 2002-2003. Lecane decipiens and Brachionus variabilis, with a maximum of respectively 6 and 4 ind L-1, were rare and quite localized in the freshwater tidal reach, corresponding to the stage III (non invasive species) in Colautti and Mac Isaac’s invasion terminology. This record of L. decipiens is the first confirmed one in Europe. Keratella tropica was generally present in the freshwater reach but, more tolerant to salinity, it was also found in brackish water. With its maximum abundance of 18 ind L-1,K. tropica appeared to be invasive, with a stage Iva (widespread but rare) at the scale of the Schelde estuary. A description with illustrations of these introduced species is given with some information about their ecology.

Published
2007

37. Zooplankton distribution across the brackish and freshwater zone of the Scheldt estuary

Author

Azémar, F., Fiers, F., and Tackx, M.

Subjects
Belgium, Schelde R, Fresh water, Brackish water, Acanthocyclops robustus, Brachionus calyciflorus, Rotifera, Distribution, Zooplankton, Acartia tonsa, Cyclopidae, Abundance, Calanoida, Species diversity, Eurytemora affinis (Poppe, 1880)
Abstract

Zooplankton diversity and distribution in the brackish and freshwater zone of the Scheldt is studied, as a continuation of preceeding studies carried out in the periods 1967-1669 and 1995-1997. We report on species diversity and abundancy of the zooplankters, collected on a monthly basis, in 20 sampling sites along the salinity gradient. Calanoids occur mainly in the brackish part, with Eurytemora affinis, Acartia tonsa and Eudiaptomus gracilis as the dominant species. In the freshwater region, rotifers (i.e. Brachionus calyciflorus, Keratella quadrata, among others), cyclopids (i.e. Acanthocyclops robustus, Cyclops vicinus) and cladocerans (Daphnia longispina, Bosmina longirostris...) are the dominant zooplankters. In addition, we report the presence of several species which were not detected in the former studies, such as the rotifers Brachionus leydigi var. quadratus, Notholca labis, Platyias quadricornis, Euchlanis dilatata, Gastropus hyptopus, Testudinella patina, Polyarthra dolichoptera and Trichotria sp. ; the cladocerans Acroperus harpae and Biapertura affinis, and the harparticoid Bryocamptus (Bryocamptus) minutus.

Published
2004

38. The predation impact of herring and sprat on estuarine zooplankton in the Scheldt estuary

Author

Maes, J., Tackx, M., and Soetaert, K.

Subjects
Belgium, Schelde R, Brackishwater fish, Predation, Stomach content, Herrings, Overwintering, Zooplankton, Migrations, Models, Population number, Food consumption, Biomass, ANE, North Sea, Construction
Abstract

Every winter, young-of-the-year herring and sprat migrate to North Sea estuaries and become the dominant member of the estuarine fish assemblage, both by numbers and by biomass. These winter migrations have been related to abiotic factors (temperature and salinity), estuarine productivity and the reduced predation pressure in turbid brackish water areas. During estuarine residency, herring and sprat mainly feed on calanoid copepods. We have estimated the food consumption of zooplankton (g C m-3 day-1) by herring and sprat which overwinter in the Scheldt estuary using two models of feeding in fish: a bioenergetic model based on physiological parameters and a model based on the change in stomach contents over time. To assess the impact of fish on the copepod biomass of the brackish part of the estuary, we have developed a simple copepod biomass model and included food consumption by fish as a biomass sink. In general, the consumption of zooplankton by fish is too low to represent a major source of copepod mortality. The low impact of fish predation may be a function of the low fish biomass in spring at a time when copepod production increases.

Published
2002

39. Study and modeling of eutrophication-related changes in coastal planktonic food-webs: a contribution of the AMORE (Advanced Modeling and Research on Eutrophication) consortium = Eutrofiëring en de structuur van het planktonisch trofisch netwerk in kustzones: mechanismen en modellering

Author

Lancelot, C., Rousseau, V., Becquevort, S., Parent, J.-Y., Breton, E., Déliat, G., Leblanc, C., Daro, M.H., Gasparini, S., Antajan, E., Meyer, A., Tackx, M., Ruddick, K., Ozer, J., and Spitz, Y.

Subjects
ANE, North Sea
Published
2002

40. Spring zooplankton communities in the Scheldt estuary: from the 60'ties till present

Author

Tackx, M.

Subjects
Belgium, Schelde R, Abundance, Fresh water, Brackish water, Suspended particulate matter, Eurytemora affinis, Oxygen compounds, Geographical distribution, Zooplankton, Composition, Taxonomy
Abstract

Abundance and taxonomical composition of the spring zooplankton community in the Scheldt is compared for the brackish water zone and the fresh water zone using data collected in the 60'ties, the 80'ties, the 90'ties and in spring 2002. Zooplankton spatial distribution is related to oxygen concentrations and particulate matter concentration and composition and hydrological conditions. Special attention is given to the Calanoid copepod Eurytemora affinis.

Published
2002

43. Origin and fate of dissolved inorganic carbon in interstitial waters of two fresh water intertidal areas: A case study of the Scheldt Estuary, Belgium

Author

Hellings, Liesbet, Dehairs, Frank, Tackx, M., Keppens, Edward, Baeyens, Willy, Analytical and Environmental Chemistry, and Vrije Universiteit Brussel

Abstract

Processes affecting the concentration and isotopiccomposition of dissolved inorganic carbon (DIC) wereinvestigated in pore waters of two freshwaterintertidal areas of the Scheldt Estuary, Belgium. Porewater δ13CDIC values from marshes andmudflats varied from −27 to +13.4‰, these very largevariations reflect the contribution of differentcarbon sources to the DIC pool. In pore waters of the upper mudflat, river water DICand dissolution of calcite contribute to a lesserextent (10% and 16% respectively) to the total DICpool. Results indicate that inorganic carbon added tothe pore water of the mudflats has a δ13Cvalue of +20.3‰ in May 1998. These strongly enrichedδ13CDIC values suggest that the majorcontribution (up to three-quarters) to total DIC isCO2 derived from methanogenesis. In pore waters of the marshes, CO2 derived fromorganic matter degradation (−27.5‰) and river DIC(−11.5 to −16.1‰) are the major sources of inorganiccarbon contribution to the total DIC pool. In porewaters from a marsh site colonised by willow trees,the contribution from CO2 derived from organicmatter degradation is larger than in pore waters froman area with only reed vegetation. In the latter caseriver water DIC is the major source of pore waterDIC.

Published
2000

45. Dynamics and trophic roles of heterotrophic protists in the plankton of a freshwater tidal estuary

Author

Muylaert, K., Van Mieghem, R., Sabbe, K., Tackx, M., and Vyverman, W.

Subjects
Bacteria, Rotifera, ANE, Belgium, Trophic relationships, Ciliophora, Estuaries, Heterotrophic organisms, Dynamics
Abstract

Freshwater tidal estuaries comprise the most upstream reaches of estuaries and are often characterised by the presence of dense bacterial and algal populations which provide a large food source for bacterivorous and algivorous protists. In 1996, the protistan community in the freshwater tidal reaches of the Schelde estuary was monitored to evaluate whether these high food levels are reflected in a similarly high heterotrophic protistan biomass. Protistan distribution patterns were compared to those of metazoan zooplankton to evaluate the possible role of top-down regulation of protists by metazoans. Apart from the algivorous sarcodine Asterocaelum, which reached high densities in summer, heterotrophic protistan biomass was dominated by ciliates and, second in importance, heterotrophic nanoflagellates (HNAN). HNAN abundance was low (annual average 2490 cells ml–1) and did not display large seasonal variation. It is hypothesised that HNAN were top-down controlled by oligotrich ciliates throughout the year and by rotifers in summer. Ciliate abundance was generally relatively high (annual average 65 cells ml–1) and peaked in winter (maximum 450 cells ml–1). The decline of ciliate populations in summer was ascribed to grazing by rotifers, which developed dense populations in that season. In winter, ciliate populations were probably regulated `internally' by carnivorous ciliates (haptorids and Suctoria). Our observations suggest that, in this type of productive ecosystems, the microbial food web is mainly top-down controlled rather than regulated by food availability.

Published
1999

50. Spatial and temporal patterns of water quality along the estuarine salinity gradient of the Scheldt estuary (Belgium and The Netherlands): results of an integrated monitoring approach

Author

van Damme, S., Struyf, E., Maris, T., Ysebaert, T., Dehairs, F., Tackx, M., Heip, C.H.R., Meire, P., van Damme, S., Struyf, E., Maris, T., Ysebaert, T., Dehairs, F., Tackx, M., Heip, C.H.R., and Meire, P.

Abstract

This paper presents the results of 7years of integrated monitoring along the Scheldt estuary. The combination of two datasets resulted in a full description of the estuaries water quality parameters from the mouth to the upper boundary, including an extended fresh water tidal part. A synthesis of the monitoring results and all relevant ecological knowledge on the Scheldt allowed to identify opportunities to optimize its management. The results show that the effect of discharge on salinity has a distinct maximum in the polyhaline to mesohaline transition area. Oxygen conditions, nitrogen removal and phytoplankton regulation can be enhanced and improved through management measures within the estuary. To lower carbon and phosphorous loads however measures should be taken within the catchment. To restore most of its ecological functions the estuary needs more space. Optimal locations to address specific functions can be derived from the monitoring results. [KEYWORDS: ecosystem management ; estuary ; nutrients ; water quality ; phytoplankton], This paper presents the results of 7years of integrated monitoring along the Scheldt estuary. The combination of two datasets resulted in a full description of the estuaries water quality parameters from the mouth to the upper boundary, including an extended fresh water tidal part. A synthesis of the monitoring results and all relevant ecological knowledge on the Scheldt allowed to identify opportunities to optimize its management. The results show that the effect of discharge on salinity has a distinct maximum in the polyhaline to mesohaline transition area. Oxygen conditions, nitrogen removal and phytoplankton regulation can be enhanced and improved through management measures within the estuary. To lower carbon and phosphorous loads however measures should be taken within the catchment. To restore most of its ecological functions the estuary needs more space. Optimal locations to address specific functions can be derived from the monitoring results. [KEYWORDS: ecosystem management ; estuary ; nutrients ; water quality ; phytoplankton]

Published
2005

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