The role of physico-chemical interactions in the seasonality of toxic dinoflagellate cyst assemblages: The case of the NW Patagonian fjords system

Harmful algal blooms (HABs) are recurrent in the NW Patagonia fjords system and their frequency has increased over the last few decades. Outbreaks of HAB species such as Alexandrium catenella, a causal agent of paralytic shellfish poisoning, and Protoceratium reticulatum, a yessotoxins producer, have raised considerable concern due to their adverse socioeconomic consequences. Monitoring programs have mainly focused on their planktonic stages, but since these species produce benthic resting cysts, the factors influencing cyst distributions are increasingly gaining recognition as potentially important to HAB recurrence in some regions. Still, a holistic understanding of the physico-chemical conditions influencing cyst distribution in this region is lacking, especially as it relates to seasonal changes in drivers of cyst distributions as the characteristics that favor cyst preservation in the sediment may change through the seasons. In this study, we analyzed the physico–chemical properties of the sediment (temperature, pH, redox potential) and measured the bottom dissolved oxygen levels in a “hotspot” area of southern Chile, sampling during the spring and summer as well as the fall and winter, to determine the role these factors may play as modulators of dinoflagellate cyst distribution, and specifically for the cysts of A. catenella and P. reticulatum. A permutational analysis of variance (PERMANOVA) showed the significant effect of sediment redox conditions in explaining the differences in the cyst assemblages between spring-summer and fall-winter periods (seasonality). In a generalized linear model (GLM), sediment redox potential and pH were associated with the highest abundances of A. catenella resting cysts in the spring-summer, however it was sediment temperature that most explained the distribution of A. catenella in the fall-winter. For P. reticulatum, only spring-summer sediment redox potential and temperature explained the variation in cyst abundances. The implications of environmental physico-chemical seasonality for the resting cysts dynamics of both species are discussed.Postprint3,74

Competencias transversales para el aprendizaje en estudiantes universitarios

El presente artículo da cuenta de la experiencia que se está realizando, desde el año 2003, en la Universidad de Los Lagos de Osorno; la que se dice relación con el Programa de Fortalecimiento de Competencias Transversales para el aprendizaje. Dentro de él se fortalecen las habilidades cognitivas y socioafectivas indispensables para enfrentar de mejor manera los desafíos que impone el aprendizaje en la universidad, lo que también será de utilidad en la vida profesional. Se pretende apoyar el proceso de integración de los estudiantes a la vida universitaria y su desempeño futuro, estableciendo un sistema de apoyo a los alumnos iniciales, para compensar los niveles de manejo insuficiente de competencias cognitivas para el aprendizaje, a través de la implementación de módulos de trabajo

Turbulence and hypoxia contribute to dense biological scattering layers in a Patagonian fjord system

The aggregation of plankton species along fjords can be linked to physical properties and processes such as stratification, turbulence and oxygen concentration. The goal of this study is to determine how water column properties and turbulent mixing affect the horizontal and vertical distributions of macrozooplankton along the only northern Patagonian fjord known to date, where hypoxic conditions occur in the water column. Acoustic Doppler current profiler moorings, scientific echo-sounder transects and in situ plankton abundance measurements were used to study macrozooplankton assemblages and migration patterns along Puyuhuapi Fjord and Jacaf Channel in Chilean Patagonia. The dissipation of turbulent kinetic energy was quantified through vertical microstructure profiles collected throughout time in areas with high macrozooplankton concentrations. The acoustic records and in situ macrozooplankton data revealed diel vertical migrations (DVM) of siphonophores, chaetognaths and euphausiids. In particular, a dense biological backscattering layer was observed along Puyuhuapi Fjord between the surface and the top of the hypoxic boundary layer ( ∼ 100&thinsp;m), which limited the vertical distribution of most macrozooplankton and their DVM, generating a significant reduction of habitat. Aggregations of macrozooplankton and fishes were most abundant around a submarine sill in Jacaf Channel. In this location macrozooplankton were distributed throughout the water column (0 to  ∼ 200&thinsp;m), with no evidence of a hypoxic boundary due to the intense mixing near the sill. In particular, turbulence measurements taken near the sill indicated high dissipation rates of turbulent kinetic energy (ε ∼ 10−5&thinsp;W&thinsp;kg−1) and vertical diapycnal eddy diffusivity (Kρ ∼ 10−3&thinsp;m2&thinsp;s−1). The elevated vertical mixing ensures that the water column is well oxygenated (3–6&thinsp;mL&thinsp;L−1, 60&thinsp;%–80&thinsp;% saturation), creating a suitable environment for macrozooplankton and fish aggregations. Turbulence induced by tidal flow over the sill apparently enhances the interchange of nutrients and oxygen concentrations with the surface layer, creating a productive environment for many marine species, where the prey–predator relationship might be favored.</p

Deep-Sea Fish Distribution Varies between Seamounts: Results from a Seamount Complex off New Zealand

Fish species data from a complex of seamounts off New Zealand termed the “Graveyard Seamount Complex’ were analysed to investigate whether fish species composition varied between seamounts. Five seamount features were included in the study, with summit depths ranging from 748–891 m and elevation from 189–352 m. Measures of fish species dominance, rarity, richness, diversity, and similarity were examined. A number of factors were explored to explain variation in species composition, including latitude, water temperature, summit depth, depth at base, elevation, area, slope, and fishing effort. Depth at base and slope relationships were significant with shallow seamounts having high total species richness, and seamounts with a more gradual slope had high mean species richness. Species similarity was modelled and showed that the explanatory variables were driven primarily by summit depth, as well as by the intensity of fishing effort and elevation. The study showed that fish assemblages on seamounts can vary over very small spatial scales, in the order of several km. However, patterns of species similarity and abundance were inconsistent across the seamounts examined, and these results add to a growing literature suggesting that faunal communities on seamounts may be populated from a broad regional species pool, yet show considerable variation on individual seamounts

Science Priorities for Seamounts: Research Links to Conservation and Management

Seamounts shape the topography of all ocean basins and can be hotspots of biological activity in the deep sea. The Census of Marine Life on Seamounts (CenSeam) was a field program that examined seamounts as part of the global Census of Marine Life (CoML) initiative from 2005 to 2010. CenSeam progressed seamount science by collating historical data, collecting new data, undertaking regional and global analyses of seamount biodiversity, mapping species and habitat distributions, challenging established paradigms of seamount ecology, developing new hypotheses, and documenting the impacts of human activities on seamounts. However, because of the large number of seamounts globally, much about the structure, function and connectivity of seamount ecosystems remains unexplored and unknown. Continual, and potentially increasing, threats to seamount resources from fishing and seabed mining are creating a pressing demand for research to inform conservation and management strategies. To meet this need, intensive science effort in the following areas will be needed: 1) Improved physical and biological data; of particular importance is information on seamount location, physical characteristics (e.g. habitat heterogeneity and complexity), more complete and intensive biodiversity inventories, and increased understanding of seamount connectivity and faunal dispersal; 2) New human impact data; these shall encompass better studies on the effects of human activities on seamount ecosystems, as well as monitoring long-term changes in seamount assemblages following impacts (e.g. recovery); 3) Global data repositories; there is a pressing need for more comprehensive fisheries catch and effort data, especially on the high seas, and compilation or maintenance of geological and biodiversity databases that underpin regional and global analyses; 4) Application of support tools in a data-poor environment; conservation and management will have to increasingly rely on predictive modelling techniques, critical evaluation of environmental surrogates as faunal “proxies”, and ecological risk assessment

Data for: Heating and hot water with wood chips. Is it convenient to replace fossil fuel and firewood boilers in southern Chile?

. Energy demand for heating and hot water: Energy demand for heating and domestic hot water of a hypothetical residential building with different thermal insulation conditions..Sizing the heating and hot water system: Sizing different design options with complementary boiler and accumulator tank considering daily and hourly temperature fluctuations. .Fuel supply costs: (i) Alternative fuel requirements based on the net calorific value of each fuel and energy demand requirements. (ii) Estimation of wood chips supply costs..Economic evaluation of system alternatives. (i) Calculation of investment costs for the heating and hot water alternative systems, the exterior insulation and finish system (EIFS) and the pipe installation for the heating network, (ii) Calculation of operation costs of the heating and hot water systems with different thermal insulation conditions, (iii) Determination of the equivalent annual costs per dwelling for one to five buildings in a network including thermal insulation improvements . (iv) Net present value of firewood boiler replacement by woodchips and by liquified petrol gas boilers

Data for: Heating and hot water with wood chips. Is it convenient to replace fossil fuel and firewood boilers in southern Chile?

. Energy demand for heating and hot water: Energy demand for heating and domestic hot water of a hypothetical residential building with different thermal insulation conditions..Sizing the heating and hot water system: Sizing different design options with complementary boiler and accumulator tank considering daily and hourly temperature fluctuations. .Fuel supply costs: (i) Alternative fuel requirements based on the net calorific value of each fuel and energy demand requirements. (ii) Estimation of wood chips supply costs..Economic evaluation of system alternatives. (i) Calculation of investment costs for the heating and hot water alternative systems, the exterior insulation and finish system (EIFS) and the pipe installation for the heating network, (ii) Calculation of operation costs of the heating and hot water systems with different thermal insulation conditions, (iii) Determination of the equivalent annual costs per dwelling for one to five buildings in a network including thermal insulation improvements . (iv) Net present value of firewood boiler replacement by woodchips and by liquified petrol gas boilers.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Data for: Heating and hot water with wood chips. Is it convenient to replace fossil fuel and firewood boilers in southern Chile?

. Energy demand for heating and hot water: Energy demand for heating and domestic hot water of a hypothetical residential building with different thermal insulation conditions..Sizing the heating and hot water system: Sizing different design options with complementary boiler and accumulator tank considering daily and hourly temperature fluctuations. .Fuel supply costs: (i) Alternative fuel requirements based on the net calorific value of each fuel and energy demand requirements. (ii) Estimation of wood chips supply costs..Economic evaluation of system alternatives. (i) Calculation of investment costs for the heating and hot water alternative systems, the exterior insulation and finish system (EIFS) and the pipe installation for the heating network, (ii) Calculation of operation costs of the heating and hot water systems with different thermal insulation conditions, (iii) Determination of the equivalent annual costs per dwelling for one to five buildings in a network including thermal insulation improvements . (iv) Net present value of firewood boiler replacement by woodchips and by liquified petrol gas boilers.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Data for: Heating and hot water with wood chips. Is it convenient to replace fossil fuel and firewood boilers in southern Chile?

. Energy demand for heating and hot water: Energy demand for heating and domestic hot water of a hypothetical residential building with different thermal insulation conditions..Sizing the heating and hot water system: Sizing different design options with complementary boiler and accumulator tank considering daily and hourly temperature fluctuations. .Fuel supply costs: (i) Alternative fuel requirements based on the net calorific value of each fuel and energy demand requirements. (ii) Estimation of wood chips supply costs..Economic evaluation of system alternatives. (i) Calculation of investment costs for the heating and hot water alternative systems, the exterior insulation and finish system (EIFS) and the pipe installation for the heating network, (ii) Calculation of operation costs of the heating and hot water systems with different thermal insulation conditions, (iii) Determination of the equivalent annual costs per dwelling for one to five buildings in a network including thermal insulation improvements . (iv) Net present value of firewood boiler replacement by woodchips and by liquified petrol gas boilers.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV