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Background Biological control programs involving Wolbachia-infected Aedes aegypti are currently deployed in different epidemiological settings. New Caledonia (NC) is an ideal location for the implementation and evaluation of such a strategy as the only proven vector for dengue virus (DENV) is Ae. aegypti and dengue outbreaks frequency and severity are increasing. We report the generation of a NC Wolbachia-infected Ae. aegypti strain and the results of experiments to assess the vector competence and fitness of this strain for future implementation as a disease control strategy in Noumea, NC. Methods/principal findings The NC Wolbachia strain (NC-wMel) was obtained by backcrossing Australian AUS-wMel females with New Caledonian Wild-Type (NC-WT) males. Blocking of DENV, chikungunya (CHIKV), and Zika (ZIKV) viruses were evaluated via mosquito oral feeding experiments and intrathoracic DENV challenge. Significant reduction in infection rates were observed for NC-wMel Ae. aegypti compared to WT Ae. aegypti. No transmission was observed for NC-wMel Ae. aegypti. Maternal transmission, cytoplasmic incompatibility, fertility, fecundity, wing length, and insecticide resistance were also assessed in laboratory experiments. Ae. aegypti NC-wMel showed complete cytoplasmic incompatibility and a strong maternal transmission. Ae. aegypti NC-wMel fitness seemed to be reduced compared to NC-WT Ae. aegypti and AUS-wMel Ae. aegypti regarding fertility and fecundity. However further experiments are required to assess it accurately. Conclusions/significance Our results demonstrated that the NC-wMel Ae. aegypti strain is a strong inhibitor of DENV, CHIKV, and ZIKV infection and prevents transmission of infectious viral particles in mosquito saliva. Furthermore, our NC-wMel Ae. aegypti strain induces reproductive cytoplasmic incompatibility with minimal apparent fitness costs and high maternal transmission, supporting field-releases in Noumea, NC., Author summary Dengue represents a risk for almost half of the world’s population, especially throughout the tropics. In New Caledonia, dengue outbreaks have become more frequent in the past decade along with the recent circulation of chikungunya and Zika viruses. The opportunity to use the biocontrol method involving the release of Wolbachia-infected Ae. aegypti mosquitoes has been investigated as an alternative solution to the traditional control methods, like elimination of larval habitats and pyrethroid insecticide application to kill adults, which are becoming insufficient. A local strain of Ae. aegypti carrying Wolbachia (NC-wMel) has been generated and tested to evaluate its pathogen blocking capacity for the four dengue virus serotypes as well as chikungunya and Zika viruses. The fitness of NC-wMel strain has also been assessed to estimate its ability to compete with the wild-type strain in the field. Noumea city, where a third of the population of New Caledonia resides, has been chosen as the first site to implement the method in New Caledonia. As Ae. aegypti is the only proven vector in New Caledonia, we expect a significant impact on dengue outbreaks occurring in Noumea as soon as a high frequency of NC-wMel is established in the population.

First recorded in the 1970s, massive green macroalgal blooms have since become an annual recurrence in Brittany, France. Eutrophication (in particular to anthropogenic nitrogen input) has been identified as the main factor controlling Ulva ‘green tide’ events. In this study, we modelled Ulva proliferation using a two-dimensional model by coupling hydrodynamic and biological models (coined ‘MARS-Ulves’) for five sites along the Brittany coastline (La Fresnaye Bay, Saint-Brieuc Bay, Lannion Bay, Guissény Bay and Douarnenez Bay). Calibration of the biological model was mainly based on the seasonal variation of the maximum nitrogen uptake rate (VmaxN) and the half-saturation constant for nitrogen (KN) to reproduce the internal nutrient quotas measured in situ for each site. In each bay, model predictions were in agreement with observed algal coverage converted into biomass. A numerical tracking method was implemented to identify the contribution of the rivers that empty into the study bays, and scenarios of decreases in nitrate concentration in rivers were simulated. Results from numerical nitrogen tracking highlighted the main nitrogen sources of green tides and also showed that each river contributes locally to green tides. In addition, dynamic modelling showed that the nitrate concentrations in rivers must be limited to between 5 and 15 mg l- 1, depending on the bay, to reduce Ulva biomass by half on the coasts. The three-step methodology developed in this study (analysing total dissolved inorganic nitrogen flux from rivers, tracking nitrogen sources in Ulva and developing scenarios for reducing nitrogen) provides qualitative and quantitative guidelines for stakeholders to define specific nitrogen reduction targets for better environmental management of water quality.

We monitored the concentrations of copper, lead and cadmium in seawater, in suspended particulatematter (SPM) and in bacteria, phyto- and zooplankton communities separated from abiogenic particles,over a one year cycle in two coupled Mediterranean coastal ecosystems (Little Bay (LiB) and Large Bay(LaB)). Metals were present in seawater in the order Cu > Pb > Cd in both bays and showed importantvariations within the same month than among months. In LiB, their concentrations were between 0.62and 2.82 l gCul 1 , 0.16 and 19 l gPbl and 0.007 and 0.14 l gCdl 1 , respectively, whereas in LaB, theywere between 0.23 and 2.11 l gCul 1 , 0.09 and 0.76 l gPbl 1 and not detected and 0.65 l gCdl 1 . SPMplay an important role on metal adsorption, especially for copper. Bioaccumulation factors showed thatbacteria and phytoplankton accumulate metals whereas zooplankton tends to biodiminish them in theplankton food web. 2008 Elsevier Ltd. All rights reserved. 1. IntroductionBays are situated between terrestrial and pelagic environmentsand constitute ecotones that may be strongly affected by humanactivities, directly or indirectly, with consequences for the func-tioning of these ecosystems. In these ecosystems, and particularlythose in the Mediterranean Sea, heavy metal concentrations maybe especially high (Danovaro, 2003). Toulon Bay (France, NW Med-iterranean Sea) is a study site of interest for field experiments forseveral reasons. First, it is divided into two systems, Little Bay(LiB) and Large Bay (LaB). These two environments are closelylinked and subject to the same climatic conditions. Second, themorphometrical characteristics and anthropogenic inputs are dif-ferent. Little Bay is a semi-enclosed system, affected by humanactivities including maritime traffic and substantial industrialactivity.Conversely, Large Bay is open to the sea andis less affectedby anthropogenic inputs and, therefore, may be considered ecolog-ically different from Little Bay.Bacteria, phytoplankton and zooplankton are determinants formetal transfer in marine food webs (Michaels and Flegal, 1990),and trace metals are included in plankton biochemical cycles(Whitfield, 2001). Among the heavy metals, copper, lead and cad-mium are of particular interest for different reasons, and may havesignificant effects on the various trophic levels in aquatic foodwebs(Fisher and Reinfelder, 1995). Copper is an essential micronu-trient for phytoplankton communities. It is involved in photosyn-thesis and in iron pathways, essential for cell growth (Peerset al., 2005). However, copper may have a negative effect on bacte-ria (Kim, 1985) on phytoplankton (Sunda and Guillard, 1976) andon the production and the survival of marine copepods (Sundaet al., 1987). Lead and cadmium are both toxic. However, leadcan be toxic at low concentrations, whereas cadmium acts as amicronutrient at low concentrations and becomes toxic at higherconcentrations (Cordero et al., 2005). Suspended particulate matteralso has an important role in the control of metal bioavailability(Sadiq, 1992). There have been several ecotoxicological studies,conducted in the laboratory and as enclosed field experiments; inparticular, these studies have investigated the various pathwaysby which plankton integrate heavy metals. In contrast, few studieshave used natural samples and one reason for this is the difficultyin obtaining pure plankton samples (Ho et al., 2007).Studies addressing how these metals are distributed in littoralplankton communities and which are conducted in situ are rare.We therefore conducted an ecological field study investigatingchanges in heavy metal concentrations in various aspects of LiBand LaB:(1) the changes in concentrations of copper, lead and cadmiumin seawater