Effect of the digenean parasites of fish on the fauna of Mediterranean lagoons.

Attention is drawn to the effects of parasites on their hosts, taking as a model the digenean parasites of teleosts (hereafter: fish) from lagoons along the French Mediterranean coast. Because digeneans have a heteroxenic life cycle, their impact is not limited to the definitive host, which harbours the sexual adults, but is extended to the first host (mollusc) and to the second host ("invertebrate" or fish). Adult parasites, in order to ensure efficient sexual reproduction, never cause excessive damage to their definitive host, usually only exploiting the intestinal fluids; however, the host must intensify its search for prey, which results in a diminished fitness.

Phytoplankton invasions: comments on the validity of categorizing the non-indigenous dinoflagellates and diatoms in European seas.

The validity of categorizing the diatoms and dinoflagellates reported in the literature as non-indigenous phytoplankton in the European Seas was investigated. Species that are synonymous are often included as separate species (Gessnerium mochimaensis=Alexandrium monilatum, Gymnodinium nagasakiense=Karenia mikimotoi, Pleurosigma simonsenii=P. planctonicum), while other species names are synonyms of cosmopolitan taxa (Prorocentrum redfieldii=P.

Defining reproductively isolated units in a cryptic and syntopic species complex using mitochondrial and nuclear markers: the brooding brittle star, Amphipholis squamata (Ophiuroidea).

At a time when biodiversity is threatened, we are still discovering new species, and particularly in the marine realm. Delimiting species boundaries is the first step to get a precise idea of diversity. For sympatric species which are morphologically undistinguishable, using a combination of independent molecular markers is a necessary step to define separate species.

Imaging oxygen distribution in marine sediments. The importance of bioturbation and sediment heterogeneity.

The influence of sediment oxygen heterogeneity, due to bioturbation, on diffusive oxygen flux was investigated. Laboratory experiments were carried out with 3 macrobenthic species presenting different bioturbation behaviour patterns: the polychaetes Nereis diversicolor and Nereis virens, both constructing ventilated galleries in the sediment column, and the gastropod Cyclope neritea, a burrowing species which does not build any structure. Oxygen two-dimensional distribution in sediments was quantified by means of the optical planar optode technique.

Assessment of three mitochondrial loci variability for the crown-of-thorns starfish: a first insight into Acanthaster phylogeography.

Acanthaster planci (L.) is one of the major threats to coral reefs, whose genetic diversity has been mainly studied with allozymes. Allozymes revealed the low genetic differentiation between A.

The Caulerpa racemosa invasion: a critical review.

Caulerpa racemosa var. cylindracea is a marine Chlorophyta introduced into the Mediterranean Sea from south-western Australia. Since 1990, it has been invading the Mediterranean Sea and the Canary Islands, raising ecological problems.

Hydrogen and trimethylsilyl transfers during EI mass spectral fragmentation of hydroxycarboxylic and oxocarboxylic acid trimethylsilyl derivatives.

This paper, describing electron ionization mass spectral fragmentation of some hydroxycarboxylic and oxocarboxylic acid trimethylsilyl derivatives, focuses on the formation of fragment ions resulting from the interactions between the two functionalities of these compounds. These interactions result in the formation of fragment ions at [CH2=C(OTMS)2]+., [CH2=CHC(OTMS)=OTMS]+, [M-31]+, [M-105]+, and [M-RCHO]+.

The status of Lecithochirium grandiporum (Rudolphi, 1819) (Digenea: Hemiuridae), a rarely reported and poorly known species from the Mediterranean moray eel Muraena helena L. in the Western Mediterranean.

A redescription of the poorly known Lecithochirium grandiporum (Rudolphi, 1819) is given based on numerous specimens collected from the stomach of the moray eel Muraena helena in the waters off the Scandola Natural Reserve, Corsica, in the Western Mediterranean. This species, abundant in all specimens of the moray eel studied in this region, is shown to be a valid species and not stunted specimens of L. fusiforme Lühe, 1901, a common parasite of the conger eel Conger conger which has developed in the wrong host.

Dissolution of dead corals by euendolithic microorganisms across the northern Great Barrier Reef (Australia).

Spatial and temporal variabilities in species composition, abundance, distribution, and bioeroding activity of euendolithic microorganisms were investigated in experimental blocks of the massive coral Porites along an inshore-offshore transect across the northern Great Barrier Reef (Australia) over a 3-year period. Inshore reefs showed turbid and eutrophic waters, whereas the offshore reefs were characterized by oligotrophic waters. The euendolithic microorganisms and their ecological characteristics were studied using techniques of microscopy, petrographic sections, and image analysis.

Influence of the Danube River inputs on C and N stable isotope ratios of the Romanian coastal waters and sediment (Black Sea).

The main aim of this study was to estimate the influence of the seasonal variations of the Danube River particulate organic matter (POM) inputs on the Black Sea surface seawater POM and upper layer of sediments along the Romanian coast. Ratios of carbon ((13)C/(12)C) and nitrogen ((15)N/(14)N) stable isotopes allowed differentiating river and marine organic matter sources. Danube River POM presented significantly lower average values of delta(13)C (-27.

Seasonal and diel distributions of denitrifying and bacterial communities in a hypersaline microbial mat (Camargue, France).

Changes in spatio-temporal distribution of bacterial and denitrifying communities were qualitatively studied in a microbial mat from Camargue (France). During a diel and a seasonal cycle, patterns of 16S rRNA and nitrite reductase genes (nirS and nirK) were compared by denaturing gradient gel electrophoresis (DGGE). Statistical analysis of DGGE profiles showed a significant seasonal shift in the community structure of the nirS-containing bacteria with a winter superficial population that extended in summer, whereas the nirK-containing bacteria seemed more affected by vertical gradients rather than by month-to month-changes.

Alkane biodegradation and dynamics of phylogenetic subgroups of sulfate-reducing bacteria in an anoxic coastal marine sediment artificially contaminated with oil.

For 503 days, unoiled control and artificially oiled sediments were incubated in situ at 20m water depth in a Mediterranean coastal area. Degradation of the aliphatic fraction of the oil added was followed by GC-MS. At the same time, terminal restriction fragment length polymorphism (T-RFLP) of 16S rRNA encoding genes was used to detect dynamics in the sulfate-reducing bacteria (SRB) community in response to the oil contamination.

Effects of spilled oil on bacterial communities of mediterranean coastal anoxic sediments chronically subjected to oil hydrocarbon contamination.

The effects of spilled oil on sedimentary bacterial communities were examined in situ at 20 m water depth in a Mediterranean coastal area. Sediment collected at an experimental site chronically subjected to hydrocarbon inputs was reworked into PVC cores with or without a massive addition of crude Arabian light oil ( approximately 20 g kg(-1) dry weight). Cores were reinserted into the sediment and incubated in situ at the sampling site (20 m water depth) for 135 and 503 days.

Free radical oxidation (autoxidation) of alkenones and other lipids in cells of Emiliania huxleyi.

Cells of the coccolithophorid Emiliania huxleyi strain CS-57 grown under an atmosphere of air+0.5% CO(2) showed oxidative damage after 10 days growth with concomitant and major changes to the lipid composition. The fatty acid profile was strongly altered and lacked appreciable amounts of the polyunsaturated fatty acids (PUFA: C(18:5), C(18:3) and C(22:6)) typical of healthy cells.

A revision of Lomasoma Manter 1935 (Digenea: Fellodistomidae), with new data on the type-specimens of four species and the description of L. triglae n. sp. from Chelidonichthys lucernus (L.) (Pisces: Triglidae) in the Western Mediterranean.

Type-specimens of Lomasoma wardi (Manter, 1934), L. monolenei (Manter, 1934), L. gracile (Manter, 1934) (emend.

A kinetic inhibition mechanism for maintenance.

To fulfil their maintenance costs, most species use mobile pools of metabolites (reserve) in favourable conditions, but can also use less mobile pools (structure) under food-limiting conditions. While some empirical models always pay maintenance costs from structure, the presence of reserve inhibits the use of structure for maintenance purposes. The standard dynamic energy budgets (DEB) model captures this by simply supplementing all costs that could not be paid from reserve with structure.

Brooding crustaceans in a highly fragmented habitat: the genetic structure of Mediterranean marine cave-dwelling mysid populations.

Habitat fragmentation and climate change are two major threats on biodiversity. Fragmentation limits the number of patches and their decreased connectivity cannot always maintain populations at dynamic equilibrium. The natural extreme fragmentation of marine cave habitats represents an opportunity to understand how these processes interact.

Relevance of various formulations of phytoplankton chlorophyll a:carbon ratio in a 3D marine ecosystem model.

Numerous experimental studies showed that the phytoplankton Chla-to-Carbon ratio (Chla:C) is highly variable, whereas most of the marine ecosystem models use a constant ratio. In this work, we tested three different formulations for computing the modelled Chla in a 3D coupled hydrodynamical-biogeochemical model of the Southwest lagoon of New Caledonia. The first formulation considers a constant Chla:C ratio.

The occurrence of the Japanese species Dinosoma lophiomi Toman, 1973 (Digenea: Hemiuridae) in Lophius piscatorius (Teleostei) from the western Mediterranean.

Hemiurid worms from the stomach of the angler Lophius piscatorius off Corsica are described and considered to belong to a Japanese species, Dinosoma lophiomi Toman, 1973, which was originally described from an Indo-Pacific lophiid host. The apparent disjunctive distribution of this species and apparent differences in the terminal genitalia between the European and Japanese specimens are discussed. This is the first record of Dinosoma Manter, 1934 from the Mediterranean Sea.

[Nitrogen fixation and primary production in Western Mediterranean].

Nitrogen fixation, nitrate assimilation and primary production ((13)C/(15)N method) were investigated during one year and half in the northwestern Mediterranean Sea. Nitrogen fixation was detectable all over the year with rates ranged from 2 to 17 nmol N l(-1) d(-1)(d). Highest values being obtained during spring associated with the phytoplankton bloom.

Does coverage matter at mesoscale within a Posidonia oceanica seagrass meadow?

Despite the fact that coverage is one of the most widely used descriptors for seagrass meadows, the spatial structure of coverage at mesoscale has not often been taken into account. The present work investigates the structure of P. oceanica coverage at mesoscale and its possible relationship with several factors (depth, type of substrate, relative level within the meadow, type of shoot density and level of anthropic pressure).

Determination of low molecular weight dicarboxylic and ketocarboxylic acids in seawater samples.

We report a new method developed for the isolation and determination of low molecular weight dicarboxylic acids and related polar compounds (C2-C9) from seawater samples. The seawater sample was first acidified and then passed through an activated charcoal column to adsorb the dicarboxylic acids. They are then desorbed with NH4OH/methanol/water mixture and derivatized with BF3/1-butanol to dibutyl esters, which are determined using a capillary GC/FID.

Choosing the right molecular genetic markers for studying biodiversity: from molecular evolution to practical aspects.

The use of molecular genetic markers (MGMs) has become widespread among evolutionary biologists, and the methods of analysis of genetic data improve rapidly, yet an organized framework in which scientists can work is lacking. Elements of molecular evolution are summarized to explain the origin of variation at the DNA level, its measures, and the relationships linking genetic variability to the biological parameters of the studied organisms. MGM are defined by two components: the DNA region(s) screened, and the technique used to reveal its variation.

Prosorhynchoides gracilescens (Rudolphi, 1819) (Digenea: Bucephalidae) from Lophius piscatorius L. is a species complex: a redescription of this species (sensu stricto) from the western Mediterranean and the description of P. borealis n. sp. from the northern North-East Atlantic.

The bucephalid digenean Prosorhynchoides gracilescens (Rudolphi, 1819) is a common intestinal parasite of the angler fish Lophius piscatorius in European marine waters. Detailed studies of new material collected off the coasts of both Marseilles and Corsica in the western Mediterranean, and comparison with museum material from the northern North-East Atlantic, indicated that the accepted concept of this species comprises two distinct taxa. The Mediterranean form occurs in relatively small numbers and has small eggs, a large rhynchus and a vitelline distribution that finishes well short of the rhynchus, whereas the NE Atlantic form, which comprises the majority of records, occurs often in large numbers, has larger eggs, a relatively smaller rhynchus and a vitelline distribution that tends to reach the rhynchus.

Four closely related but forgotten species of Rhipidocotyle Diesing, 1858 (Digenea: Bucephalidae) in fishes from European seas.

The following species of Rhipidocotyle are described: R. minima (Wagener, 1852) from Chelidonichthys gurnardus, C. lastoviza and Aspitrigla cuculus at various localities off the British Isles; R.