Phenology of scyphozoan jellyfish species in a eutrophication and climate change context.

The uprising interest in gelatinous zooplankton populations must cope with a lack of robust time series of direct abundance observations in most of the ecosystems because of the difficulties in sampling small, fragile organisms, and of the dismissal of jellyfish as a nuisance. Most of the hypotheses about their dynamics are built on a few species and ecosystems and extended to the whole group, but the blooms are registered mainly for the members of the Class Scyphozoa that dwell in temperate, shallow waters. Within the scyphozoans, our knowledge about their phenology relies mainly on laboratory experiences.

Atmospheric-ocean coupling drives prevailing and synchronic dispersal patterns of marine species with long pelagic durations.

Dispersal shapes population connectivity and plays a critical role in marine metacommunities. Prominent species for coastal socioecological systems, such as jellyfish and spiny lobsters, feature long pelagic dispersal phases (LPDPs), which have long been overlooked. Here, we use a cross-scale approach combining field surveys of these species with a high-resolution hydrodynamic model to decipher the underlying mechanisms of LPDP patterns in northwestern Mediterranean shores.

Interannual changes in zooplankton echo subtropical and high latitude climate effects in the southern East China Sea.

Climate variability plays a central role in the dynamics of marine pelagic ecosystems shaping the structure and abundance changes of plankton communities, thereby affecting energy pathways and biogeochemical fluxes in the ocean. Here we have investigated complex interactions driven a climate-hydrology-plankton system in the southern East China Sea over the period 2000 to 2012. In particular, we aimed at quantifying the influence of climate phenomena playing out in tropical (El Nino 3.

Time-varying environmental control of phytoplankton in a changing estuarine system.

Estuaries are among the most valuable aquatic systems by their services to human welfare. However, increasing human activities at the watershed along with the pressure of climate change are fostering the co-occurrence of multiple environmental drivers, and warn of potential negative impacts on estuaries resources. At present, no clear understanding of how coastal ecosystems will respond to the non-stationary effect of multiple drivers.

Interannual abundance changes of gelatinous carnivore zooplankton unveil climate-driven hydrographic variations in the Iberian Peninsula, Portugal.

The persistent massive blooms of gelatinous zooplankton recorded during recent decades may be indicative of marine ecosystem changes. In this study, we investigated the potential influence of the North Atlantic climate (NAO) variability on decadal abundance changes of gelatinous carnivore zooplankton in the Mondego estuary, Portugal, over the period 2003-2013. During the 11-year study, the community of gelatinous carnivores encompassed a larger diversity of hydromedusae than siphonophores; the former dominated by Obelia spp.

Identifying the drivers of abundance and size of the invasive ctenophore Mnemiopsis leidyi in Northwestern Mediterranean lagoons.

Acknowledged as among the worst invasive marine species, Mnemiopsis leidyi has spread through European Seas since the mid-1980's. Here we report a bimonthly survey conducted in 2010-11 in three lagoons (Bages-Sigean, Thau and Berre) and at two adjacent coastal stations (Sète and SOMLIT-Marseille) along the French Mediterranean coast. M.

Habitat association of larval fish assemblages in the northern Persian Gulf.

We examined the habitat use of fish larvae in the northern Persian Gulf from July 2006 to June 2007. Correspondence Analysis showed significant differences between hydrological seasons in habitat use and structure of larval fish assemblages, while no differences were found regarding abundance among coralline and non-coralline habitats. The observed configuration resulted in part from seasonal reproductive patterns of dominant fish influencing the ratio pelagic:demersal spawned larvae.

Microplankton dynamics under heavy anthropogenic pressure. The case of the Bahía Blanca Estuary, southwestern Atlantic Ocean.

Quantifying biotic feedbacks in response to environmental signals is fundamental to assess ecosystem perturbation. We analyzed the joint effects of eutrophication, derived from sewage pollution, and climate at the base of the pelagic food web in the Bahía Blanca Estuary (SW Atlantic Ocean). A two-year survey of environmental conditions and microplankton communities was conducted in two sites affected by contrasting anthropogenic eutrophication conditions.

Climate variance influence on the non-stationary plankton dynamics.

We examined plankton responses to climate variance by using high temporal resolution data from 1988 to 2007 in the Western English Channel. Climate variability modified both the magnitude and length of the seasonal signal of sea surface temperature, as well as the timing and depth of the thermocline. These changes permeated the pelagic system yielding conspicuous modifications in the phenology of autotroph communities and zooplankton.

Increasing zooplankton variance in the late 1990s unveils hydroclimate modifications in the Balearic Sea, Western Mediterranean.

We examined seasonal and interannual patterns of zooplankton functional groups in the Balearic Sea from 1994 to 2003 and revealed a conspicuous increase in zooplankton variance at community and population levels. The change occurred in 1999-2000, and paralleled modifications in the North Atlantic climate that cascaded down affecting the water column thermal gradient in the Balearic Sea. The observed modifications in both hydroclimate and ecological compartments raise the question of a potential ecological shift in the pelagic ecosystem of the Western Mediterranean in the late 1990s.

The Mediterranean Sea regime shift at the end of the 1980s, and intriguing parallelisms with other European basins.

Background: Regime shifts are abrupt changes encompassing a multitude of physical properties and ecosystem variables, which lead to new regime conditions. Recent investigations focus on the changes in ecosystem diversity and functioning associated to such shifts. Of particular interest, because of the implication on climate drivers, are shifts that occur synchronously in separated basins.

Phenological changes in the Northwestern Mediterranean copepods Centropages typicus and Temora stylifera linked to climate forcing.

Planktonic copepods play a major role in the fluxes of matter and energy in the marine ecosystem, provide a biological pump of carbon into the deep ocean, and play a role in determining fish recruitment. Owing to such ecological considerations, it is essential to understand the role that climate might play in the interannual variability of these organisms and the mechanisms by which it could modify the ecosystem functioning. In this study, a causal chain of meteorological, hydrological and ecological processes linked to the North Atlantic Oscillation (NAO) was identified in the Ligurian Sea, Northwestern Mediterranean.

Spatial distribution of the copepod Centropages typicus in Ligurian Sea (NW Mediterranean). Role of surface currents estimated by Topex-Poseidon altimetry.

A particle-tracking model was used to simulate the dispersion and development of the planktonic copepod Centropages typicus during spring in Ligurian Sea. We show that mesoscale current structure, with a coastal jet and eddies, plays a key role in the transport and dispersion of C. typicus during its life cycle.