Managing fisheries to conserve North Sea groundfish and benthic invertebrate species diversity

Concerns over man’s impact on the environment and ecosystems of the world have resulted in a shift in emphasis in the management of marine natural resources. Consequently, an ecosystem approach to management (EAM) is in the process of being developed and implemented for the North Se

CD40, autophagy and Toxoplasma gondii

Toxoplasmagondii represents a pathogen that survives within host cells by preventing the endosomal-lysosomal compartments from fusing with the parasitophorous vacuoles. The dogma had been that the non-fusogenic nature of these vacuoles is irreversible. Recent studies revealed that this dogma is not correct. Cell-mediated immunity through CD40 re-routes the parasitophorous vacuoles to the lysosomal compartment by a process called autophagy. Autophagosome formation around the parasitophorous vacuole results in killing of the T. gondii. CD40-induced autophagy likely contributes to resistance against T. gondii particularly in neural tissue

Visualization and Identification of IL-7 Producing Cells in Reporter Mice

Interleukin-7 (IL-7) is required for lymphocyte development and homeostasis although the actual sites of IL-7 production have never been clearly identified. We produced a bacterial artificial chromosome (BAC) transgenic mouse expressing ECFP in the Il7 locus. The construct lacked a signal peptide and ECFP (enhanced cyan fluorescent protein ) accumulated inside IL-7-producing stromal cells in thoracic thymus, cervical thymus and bone marrow. In thymus, an extensive reticular network of IL-7-containing processes extended from cortical and medullary epithelial cells, closely contacting thymocytes. Central memory CD8 T cells, which require IL-7 and home to bone marrow, physically associated with IL-7-producing cells as we demonstrate by intravital imaging

Visualization and Identification of IL-7 Producing Cells in Reporter Mice

Interleukin-7 (IL-7) is required for lymphocyte development and homeostasis although the actual sites of IL-7 production have never been clearly identified. We produced a bacterial artificial chromosome (BAC) transgenic mouse expressing ECFP in the Il7 locus. The construct lacked a signal peptide and ECFP (enhanced cyan fluorescent protein ) accumulated inside IL-7-producing stromal cells in thoracic thymus, cervical thymus and bone marrow. In thymus, an extensive reticular network of IL-7-containing processes extended from cortical and medullary epithelial cells, closely contacting thymocytes. Central memory CD8 T cells, which require IL-7 and home to bone marrow, physically associated with IL-7-producing cells as we demonstrate by intravital imaging

Climate change facilitated range expansion of the non-native angular crab Goneplax rhomboides into the North Sea

The angular crab Goneplax rhomboides is native to the north-eastern Atlantic and Mediterranean Sea. It has rarely been reported from the North Sea, with no evidence of sustainable populations. Compiled survey data, however, revealed an increasing abundance of this species in the North Sea since 2000. The data were used to (1) describe the range expansion of the angular crab into the North Sea; and (2) to apply species distribution modeling (maximum entropy approach–MAXENT) to predict the potential habitats of this species. Habitats of species with a similar ecology were modeled to analyse habitat overlap and potential competition. The spatial and temporal patterns of records revealed that the expansion of the angular crab into the North Sea is due to natural larval dispersal rather than anthropogenic vectors. Modeled habitats of the angular crab showed a core distribution area along the Scottish coastline and in the southern North Sea. Sea bottom temperatures in February had the highest influence on the model results. We concluded that the angular crab has extended its distribution range from the north-eastern Atlantic to the North Sea, which was facilitated by an increase in water temperature and the prevailing hydrodynamics over the last decade. This was the first time that a benthic range expansion was observed in quasi real time for the North Sea. Habitats of the angular crab overlapped those of possible competitors to a large extent. However, co-existence of the species is expected rather than any negative effects resulting from the range expansion of the angular cra

Climate change facilitated range expansion of the non-native angular crab Goneplax rhomboides into the North Sea

The angular crab Goneplax rhomboides is native to the north-eastern Atlantic and Mediterranean Sea. It has rarely been reported from the North Sea, with no evidence of sustainable populations. Compiled survey data, however, revealed an increasing abundance of this species in the North Sea since 2000. The data were used to (1) describe the range expansion of the angular crab into the North Sea; and (2) to apply species distribution modeling (maximum entropy approach–MAXENT) to predict the potential habitats of this species. Habitats of species with a similar ecology were modeled to analyse habitat overlap and potential competition. The spatial and temporal patterns of records revealed that the expansion of the angular crab into the North Sea is due to natural larval dispersal rather than anthropogenic vectors. Modeled habitats of the angular crab showed a core distribution area along the Scottish coastline and in the southern North Sea. Sea bottom temperatures in February had the highest influence on the model results. We concluded that the angular crab has extended its distribution range from the north-eastern Atlantic to the North Sea, which was facilitated by an increase in water temperature and the prevailing hydrodynamics over the last decade. This was the first time that a benthic range expansion was observed in quasi real time for the North Sea. Habitats of the angular crab overlapped those of possible competitors to a large extent. However, co-existence of the species is expected rather than any negative effects resulting from the range expansion of the angular cra

Sea surface water temperatures over the period 1884-1983 reconstructed from oxygen isotope ratios of a bivalve mollusk shell (Arctica Islandica, Southern North Sea)

Although climate system modeling cannot be imagined without long sea surface temperature (SST) records, observational data is spatiotemporally incomplete and inhomogeneous prior to about 1950. Moreover, almost no high-resolution SST proxies exist from temperate and boreal marine settings. Here, we present a temporally equidistant, high-resolution SST proxy record of the southern North Sea during the period 1884-1983 calculated from oxygen isotope ratios (delta(18)O(aragonite)) of Arctica islandica (L.), a bivalve mollusk shell. Arctica islandica produces daily growth increments, which enable precise intraannual dating. The growing season of specimens from about 25 m water depth (upper well-mixed layer of the ocean) started in February and ended in September. Observational (COADS, e c.) and delta(18)O(aragonite)-derived SST data during February through September compare well to each other, especially after 1950. Apart from similar overall SST trends, we found North Atlantic Oscillation-type cycles of 7-9 years in our proxy SST record and in various different instrumentally determined SST chronologies. No vital effects exist, so that delta(18)O(aragonite) ratios determined across the shell (i.e., throughout lifetime) of the studied specimen reflect ambient water temperatures that occurred during shell growth. Results of our study demonstrate that A. islandica provides long, independent and high-resolution SST proxy chronologies from higher latitudes. Such records can complement and further validate observational SST data and help improving climate system models