Search results for "Aquatic science"
showing 10 items of 2026 documents
Long-term dynamics of pelagic fish density and vendace (Coregonus albula (L.)) stocks in four zones of a lake differing in trawling intensity
2001
– An 11-year time series of hydroacoustic fish density estimates and fisheries statistics of vendace (Coregonus albula (L.)) from four zones of a lake differing in trawling intensity was analyzed in order to test the hypothesis that intensive trawling has detrimental effects on pelagic fish stocks, especially vendace recruitment. The standardized fish density estimate in trawled zones showed no decrease in comparison to the non-trawled zone. No signs of recruitment failure associable with trawling intensity were found. The growth of vendace at the end of the study period was slower than that at the beginning, indicating a higher density, most clearly so in the zone with highest trawling int…
Oxidation, efflux, and isotopic fractionation of methane during autumnal turnover in a polyhumic, boreal lake
2007
[1] We studied the oxidation and efflux of methane (CH4) in a small, polyhumic lake, Mekkojarvi (southern Finland), during 6 weeks in autumn when the stability of the water mass first weakened, temporarily restabilized, and finally mixed completely. During the summer stratification period, CH4 had accumulated in the anoxic hypolimnion to high concentrations (>150 mmol m−3). Gradual mixing of the water column during the autumn allowed access to both oxygen and CH4 by aerobic methane-oxidizing bacteria (MOB) deeper in the water column. Thus the bulk (∼83–88%) of the CH4 accumulated in the hypolimnion was subsequently consumed by MOB while only 12–17% was lost from the lake to the atmosphere a…
Modeling suggests that oblique extension facilitates rifting and continental break-up
2012
[1] In many cases the initial stage of continental break-up was and is associated with oblique rifting. That includes break-up in the Southern and Equatorial Atlantic, separation from eastern and western Gondwana as well as many recent rift systems, like Gulf of California, Ethiopia Rift and Dead Sea fault. Using a simple analytic mechanical model and advanced numerical, thermomechanical modeling techniques we investigate the influence of oblique extension on the required tectonic force in a three-dimensional setting. While magmatic processes have been already suggested to affect rift evolution, we show that additional mechanisms emerge due to the three-dimensionality of an extensional syst…
Genetic-based evaluation of management units for sustainable vendace (Coregonus albula) fisheries in a large lake system
2022
Abstract The goal of the processing industry, trade and consumers is to get eco-labelled freshwater fish products from sustainable fisheries into the market as soon as possible. The fourth largest natural lake system in Europe, the Saimaa lake system supports a fishery for vendace (Coregonus albula). Certification of the fishery requires an understanding of population structure to help determine the number and spatial extent of management units. In this study, we analysed the genetic diversity of local vendace populations in the Saimaa lake system and aimed to identify the conservation and management units of vendace. Within the Saimaa, the genetic divergence between local populations of ve…
Storm Energy Flux Characterization along the Mediterranean Coast of Andalusia (Spain)
2019
This paper investigates wave climate and storm characteristics along the Mediterranean coast of Andalusia, for the period 1979&ndash
The behaviour of REEs in Thailand's Mae Klong estuary: Suggestions from the Y/Ho ratios and lanthanide tetrad effects
2007
Abstract The concentrations of Rare Earth Elements and yttrium (REY) were measured in dissolved phase, in suspended particulate matter (SPM) and in sediments in seven sampling stations in the Mae Klong estuarine system (Inner Thailand Gulf) in order to study their behaviour and distribution pattern. The analysed samples generally show high Rare Earth Element (REE) content in the dissolved phase, with high Medium Rare Earth Elements (MREEs) and Y enrichments in the shale-normalized pattern (versus PAAS). These chemical features are interpreted in terms of direct influences of weathering processes of REE-rich minerals (e.g., phosphates), which abundantly out-crop in the Mae Klong watershed. T…
Preface: New challenges in anostracan research, a tribute to Graziella Mura
2017
This special volume of Hydrobiologia is dedicated to the memory of Graziella Mura, who unexpectedly passed away on 23 March 2016 when she was still carrying out her highly influential and worldrenowned research on Anostraca. She provided outstanding contributions to the current knowledge of the taxonomy and ecology of this distinctive crustacean group over the last 45 years. This volume is a tribute to her and her role in anostracan research by the community of anostracan specialists.
Efficacy of a bivalent vaccine against eel diseases caused by Vibrio vulnificus after its administration by four different routes
2003
Vulnivaccine, a vaccine against vibriosis caused by Vibrio vulnificus serovar E (formerly biotype 2), confers acceptable levels of protection to eels after its administration by prolonged immersion in three doses. Recently, a new pathogenic serovar, named serovar A, has been isolated from vaccinated eels in a Spanish freshwater eel farm. The main objective of this work was to design a bivalent vaccine, and to study its effectiveness against the two pathogenic serovars. With this aim, eels weighing around 20 g were immunised with the bivalent vaccine by oral and anal intubation, intraperitoneal injection (i.p.) and prolonged immersion. The overall results indicated that: (i) the new vaccine …
Contributions of autochthonous and allochthonous sources to dissolved organic matter in a large, shallow, eutrophic lake with a highly calcareous cat…
2013
We traced the origin of dissolved organic matter (DOM) in the large, shallow, eutrophic Lake Vortsjarv in Estonia. Allochthonous DOM (Al-DOM) had higher δ13C values than autochthonous DOM (Au-DOM). The δ13C of inflow DOM varied from −28.2‰ to −25.4‰ (mean −26.7‰) and in-lake DOM varied from −28.4‰ to −26.1‰ (mean −27.2‰). Low stable isotope (SI) signatures of Au-DOM were caused by relatively 13C-depleted values of its precursors (mainly phytoplankton) with mean δ13C of −28.9‰. SI signatures of dissolved inorganic carbon (DIC) in the inflows and in the lake were also relatively low (from −15.1‰ to −3.28‰). SI values of DOM were lower during the active growing season from May to September and…
Ecotoxicity assessment of natural attenuation effects at a historical dumping site in the western Baltic Sea.
2005
During the late 1950s and early 1960s of the past century, industrial waste material highly enriched in various contaminants (heavy metals, PAHs) was dumped in the inner Mecklenburg Bay, western Baltic Sea. Large-scale shifts in the spatial distribution of heavy metals in surface sediments were mapped by geochemical monitoring in the mid-1980s and 12 years later in 1997. A further study in 2001 was designed to investigate the small-scale spatial distribution of contaminants inside, on top of, and around the historical dumping ground and to examine possible effects to benthic organisms (Arctica islandica, microbiological toxicity tests). The site is located within an area characterized by a …