Alfred Giard et ses élèves Jules Bonnier et Philippe François. In "Du naturalisme à l'écologie", edité par F.G. Schmitt

L'année 2008 a marqué le centenaire de la mort de d'Alfred Giard, qui a été l'initiateur des recherches et observations sur la côte d'opale, et de l'établissement d'institutions de recherche à Wimereux. Auteur de plusieurs centaines d'articles, il a fait connaître Wimereux à l'étrangerà travers ses travaux. Par ses observations réalisés sur la côte d'opale, il a été le premier à faire connaître cet environnement au sein de la littérature scientifique internationale. Lorsqu'il a fondé la station zoololique de Wimereux en 1874 il s'agissait du quatrième laboratoire maritime ouvert sur les littoraux français, après Concarneau,Marseille et Roscoff. Nous avons organisé en juillet 2008 un coloque international et interdisciplinaire pour marquer le centenaire de la disparition d'Alfred Giard. Une première journée a été consacrée à des aspects historiques liés à l'activite scientifique de Giard : histoire des stations marines, histoire des activités de recherches marines dans le Boulonnais, histoire des théories sur l'évolution. Laseconde journée a été consacrée à l'écologie et observation de l'écosystème de la côte d'opale. Cet article d'introduction rappelle certains faits sur Giard,sur les stations de Wimereux et de la côte d'opale, et sur leur héritage et introduit les autres contribution

Distribution patterns in the benthic diversity of the eastern English Channel

Understanding the distribution of specific diversity is currently an important focus in marine research, and the role of marine biodiversity has been fully recognised as essential for the proper functioning of the biosphere. The objective of this study was to explain the distribution of macrobenthic taxonomic richness (vagile epifauna, endofauna and sessile epifauna) in the eastern part of the English Channel using both classical methods and applying the mid-domain effect (MDE) model. High diversity was encountered in the eastern English Channel (875 taxa), with high-diversity areas often comprising gravelly or pebbly sediments. Sessile epifauna represented 25% of this inventory, revealing the importance of this group. Our results underline the existence of randomness in the observed species richness distribution due to large number of species with restricted ranges

Assessment of benthic ecosystem functioning through trophic web modelling: the example of the eastern basin of the English Channel and the Southern Bight of the North Sea

Abstract Benthic organisms appear to be accurate proxies for assessing coastal ecosystem structures and changes due to climatic and anthropogenic stresses. Functional studies of benthic systems are relatively recent, mainly because of the difficulties in obtaining the basic parameters for each benthic compartment (i.e. detritus, bacteria, meiofauna and macrofauna). Our study focuses on the eastern basin of the English Channel and the Southern Bight of the North Sea. Trophic web modelling was used to assess the functioning of the three main benthic community assemblages. To test and assess the relative importance of factors assumed to influence trophic structure (geographical environment and sedimentary particle size distribution), the study area was subdivided into divisions defined a priori according to the two main structural factors of community distribution; geographic distribution and sedimentary patterns. Then, a steady state trophic model utilising the inverse method was applied to a diagram composed of eight compartments, including detritus, bacteria, meiofauna, macrobenthos and fish. For each compartment, six physiological parameters were assessed, based on our own data, empirical relationships and literature data. This method allowed estimation of the flux of matter and energy within and between the units of the benthic system and assessment of the amount of trophic energy stored in these units (available mostly to fish). Our results showed that suspension-feeders control most of the matter transfer through the macrobenthic food-web, except in the fine sand community, where deposit-feeders play a dominant role. The results also showed that, whatever the geographic area, trophic structure is strongly linked to the sedimentary conditions. As benthic communities are connected through hydrodynamics, a model of the entire eastern basin of the English Channel would appear to be acceptable. However, the main sediment types must be taken into account when establishing relationships between the functional units

Assessment of Benthic Ecosystem Functioning Through Trophic Web Modelling : The Example of the Eastern Basin of the English Channel and the Southern Bight of the North Sea

International audienceBenthic organisms appear to be accurate proxies for assessing coastal ecosystem structures and changes due to climatic and anthropogenic stresses. Functional studies of benthic systems are relatively recent, mainly because of the difficulties in obtaining the basic parameters for each benthic compartment (i.e. detritus, bacteria, meiofauna and macrofauna). Our study focuses on the eastern basin of the English Channel and the Southern Bight of the North Sea. Trophic web modelling was used to assess the functioning of the three main benthic community assemblages. To test and assess the relative importance of factors assumed to influence trophic structure (geographical environment and sedimentary particle size distribution), the study area was subdivided into divisions defined a priori according to the two main structural factors of community distribution; geographic distribution and sedimentary patterns. Then, a steady state trophic model utilising the inverse method was applied to a diagram composed of eight compartments, including detritus, bacteria, meiofauna, macrobenthos and fish. For each compartment, six physiological parameters were assessed, based on our own data, empirical relationships and literature data. This method allowed estimation of the flux of matter and energy within and between the units of the benthic system and assessment of the amount of trophic energy stored in these units (available mostly to fish). Our results showed that suspension-feeders control most of the matter transfer through the macrobenthic food-web, except in the fine sand community, where deposit-feeders play a dominant role. The results also showed that, whatever the geographic area, trophic structure is strongly linked to the sedimentary conditions. As benthic communities are connected through hydrodynamics, a model of the entire eastern basin of the English Channel would appear to be acceptable. However, the main sediment types must be taken into account when establishing relationships between the functional unit

Linking macrobenthic communities structure and zonation patterns on sandy shores : Mapping tool toward management and conservation perspectives in Northern France

International audienceIn a context of intensifying anthropogenic pressures on sandy shores, the mapping of benthic habitat appears as an essential first step and a fundamental baseline for marine spatial planning, ecosystem-based management and conservation efforts of soft-sediment intertidal areas. Mapping allows representing intertidal habitats that are basically characterised by abiotic (e.g sediments, exposure to waves…) and biotic factors such as macrobenthic communities. Macrobenthic communities are known to show zonation patterns across sandy beaches and many studies highlighted the existence of three biological zones. We tested this general model of a tripartite biological division of the shore at a geographical scale of policy, conservation and management decisions (i.e. Northern France coastline), using multivariate analyses combined with the Direct Field Observation (DFO) method. From the upper to the lower shores, the majority of the beaches exhibited three macrobenthic communities confirming the existence of the tripartite biological division of the shore. Nevertheless, in some cases, two or four zones were found: (1) two zones when the drying zone located on the upper shore was replaced by littoral rock or engineering constructions and (2) four zones on beaches and estuaries where a muddy-sand community occurred from the drift line to the mid shore. The correspondence between this zonation pattern of macrobenthic communities and the EUNIS habitat classification was investigated and the results were mapped to provide a reference state of intertidal soft-sediment beaches and estuaries. Our results showed evidence of the applicability of this EUNIS typology for the beaches and estuaries at a regional scale (Northern France coastline) with a macroecological approach. In order to fulfil the requirements of the European Directives (WFD and MFSD), this mapping appears as a practical tool for any functional study on these coastal ecosystems, for the monitoring of anthropogenic activities and for the implementation of management plans concerning effective conservation strategies

Warm-water decapods are associated with the trophic amplification of climate warming in the North Sea

International audienceA long-term time series of plankton and benthic records in the North Sea indicates an increase in decapods and a decline in their prey species that include bivalves and flatfish recruits. Here, we show that in the southern North Sea the proportion of decapods to bivalves doubled following a temperature-driven, abrupt ecosystem shift during the 1980s. Analysis of decapod larvae in the plankton reveals a greater presence and spatial extent of warm-water species where the increase in decapods is greatest. These changes paralleled the arrival of new species such as the warm-water swimming crab Polybius henslowii now found in the southern North Sea. We suggest that climate-induced changes among North Sea decapods have played an important role in the trophic amplification of a climate signal and in the development of the new North Sea dynamic regime

Regional patterns of continental shelf polychaete diversity: examples for the North Sea, English Channel, Irish Sea and Outer Bristol Channel areas

International audiencePolychaetes are a well-represented group in most marine and estuarine environments, both in terms of number of individuals and species; they typically constitute a significant percentage of the total macrofaunal diversity. The aim of our analyses was to characterise the biodiversity and regional distribution patterns of polychaete assemblages from the continental shelf (0-200 m) of the North Sea, English Channel and Irish Sea. Variations in depth and local distribution of sediment types, amongst other environmental factors, are the main factors affecting the pattern of distribution of benthic polychaetes. Here we applied and compared different approaches to draw the diversity pattern of this marine invertebrate group on a regional biogeographical scale, and to identify the main factors structuring these patterns

Les espèces marines animales et végétales introduites dans le bassin Artois-Picardie

Cet ouvrage est le fruit d’une collaboration entre l’Agence de l’Eau Artois-Picardie et le Laboratoire d’Océanologie et de Géosciences de Wimereux (LOG). Il recense les espèces marines animales et végétales introduites sur la Côte d’Opale, en région Nord - Pas-de-Calais: le but de l'ouvrage est de présenter la liste la plus exhaustive possible des espèces marines introduites. Sont présentés la biologie, l'habitat, la date d'introduction parfois estimée ou la date de première signalisation, la répartition de l'espèce dans les mers avoisinantes ainsi que les problèmes environnementaux qu'elle pose éventuellement