Search

Declines of large predatory fish due to overexploitation are restructuring food webs across the globe. It is now becoming evident that restoring these altered food webs requires addressing not only ecological processes, but evolutionary ones as well, because human-induced rapid evolution may in turn affect ecological dynamics. We studied the potential for niche differentiation between different plate armor phenotypes in a rapidly expanding population of a small prey fish, the three-spined stickleback (Gasterosteus aculeatus). In the central Baltic Sea, three-spined stickleback abundance has increased dramatically during the past decades. The increase in this typical mesopredator has restructured near-shore food webs, increased filamentous algal blooms, and threatens coastal biodiversity. Time-series data covering 22 years show that the increase coincides with a decline in the number of juvenile perch (Perca fluviatilis), the most abundant predator of stickleback along the coast. We investigated the distribution of different stickleback plate armor phenotypes depending on latitude, environmental conditions, predator and prey abundances, nutrients, and benthic production; and described the stomach content of the stickleback phenotypes using metabarcoding. We found two distinct lateral armor plate phenotypes of stickleback, incompletely and completely plated. The proportion of incompletely plated individuals increased with increasing benthic production and decreasing abundances of adult perch. Metabarcoding showed that the stomach content of the completely plated individuals more often contained invertebrate herbivores (amphipods) than the incompletely plated ones. Since armor plates are defense structures favored by natural selection in the presence of fish predators, the phenotype distribution suggests that a novel low-predation regime favors stickleback with less armor. Our results suggest that morphological differentiation of the three-spined stickleback has the po

Removal of organic and inorganic sulfur compounds from sour gases is required because of their toxicity and atmospheric pollution. The most common are hydrogen sulfide (H2S) and methanethiol (MT). Under oxygen-limiting conditions about 92 mol% of sulfide is oxidized to sulfur by haloalkaliphilic sulfur-oxidizing bacteria (SOB), whilst the remainder is oxidized either biologically to sulfate or chemically to thiosulfate. MT is spontaneously oxidized to dimethyl disulfide (DMDS), which was found to inhibit the oxidation of sulfide to sulfate. Hence, we assessed the effect of DMDS on product formation in a lab-scale biodesulfurization setup. DMDS was quantified using a newly, in-house developed analytical method. Subsequently, a chemical reaction mechanism was proposed for the formation of methanethiol and dimethyl trisulfide from the reaction between sulfide and DMDS. Addition of DMDS resulted in significant inhibition of sulfate formation, leading to 96 mol% of sulfur formation. In addition, a reduction in the dominating haloalkaliphilic SOB species, Thioalkalivibrio sulfidiphilus, was observed in favor of Thioalkaibacter halophilus as a more DMDS-tolerant with the 50 % inhibition coefficient at 2.37 mM DMDS., BT/Environmental Biotechnology

The growth of the global population and its associated increased demands for energy, food, and water has resulted in the intensification of industry and land use and hence loss of biodiversity and climate change. The overuse of natural resources, anthropogenic gas emissions and wastewater discharges into open waters cause environmental pollution, which, as a chain reaction, trigger  changes in the natural habitats of flora and fauna. Moreover, accumulation of CO2, N2O, CH4 and SO2 gases in the atmosphere cause health problems for millions of people and accelerate climate change.To sustain a global population of 7.7 billion people and manage their environmental footprint sustainably, the industry should transition towards a circular economy by using renewable resources and implementation of sustainable technologies. One such technology is the gas biodesulfurization process developed by our group in the Department of Environmental Technology at Wageningen University in cooperation with Delft University of Technology, University of Amsterdam, and industrial partners: Paqell B.V, Paques B.V and Shell. This technology emerged in the early 1990s when physicochemical desulfurization processes were dominating the market. Our biodesulfurization technology distinguishes itself because of its reduced operational and capital expenditures, and smaller environmental footprint. Since then, gas biodesulfurization has been intensively studied in order to facilitate higher sulfur recovery rates (>90 mol%) and stable process operations while treating a variety of gas feed streams. A high selectivity for sulfur is preferred because this will regenerate hydroxide ions, which are consumed when H2S is removed from gas streams. In addition, the consumption of air, energy, and caustic at sulfur-producing conditions are lower relative to the formation of sulfuric acid. Furthermore, the recovered sulfur slurry can be used as fertilizer and as fungicide. To maintain a stable sulfur select