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The impact of electrogenic sulfur oxidation on the biogeochemistry of coastal sediments: A field study
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Electro-active sediments distinguish themselves from other sedimentary environments by the presence of microbially induced electrical currents in the surface layer of the sediment. The electron transport is generated by metabolic activity of long filamentous cable bacteria, in a process referred to as electrogenic sulfur oxidation (e-SOx). Laboratory experiments have shown that e-SOx exerts a large impact on the sediment geochemistry, but its influence on the in situ geochemistry of marine sediments has not been previously investigated. Here, we document the biogeochemical cycling associated with e-SOx in a cohesive coastal sediment in the North Sea (Station 130, Belgian Coastal Zone) during three campaigns (January, March and May 2014). Fluorescence in situ hybridization showed that cable bacteria were present in high densities throughout the sampling period, and that filaments penetrated up to 7 cm deep in the sediment, which is substantially deeper than previously recorded. High resolution microsensor profiling (pH, H2S and O2) revealed the typical geochemical fingerprint of e-SOx, with a wide separation (up to 4.8 cm) between the depth of oxygen penetration and the depth of sulfide appearance. The metabolic activity of cable bacteria induced a current density of 25–32 mA m-2 and created an electrical field of 12–17 mV m-1 in the upper centimeters of the sediment. This electrical field created an ionic drift, which strongly affected the depth profiles and fluxes of major cations (Ca2+, Fe2+) and anions (SO42-) in the pore water. The strong acidification of the pore water at depth resulted in the dissolution of calcium carbonates and iron sulfides, thus leading to a strong accumulation of iron, calcium and manganese in the pore water. While sulfate accumulated in the upper centimeters, no significant effect of e-SOx was found on ammonium, phosphate and silicate depth profiles. Overall, our results demonstrate that cable bacteria can strongly modulate the sedimentary biogeochemical cycling under in situ conditions
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No RBINS Staff publications
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The impact of sand extraction on the wave height near the Belgian coast
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RBINS Staff Publications 2021
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The Influence of Bioturbation on Iron and Sulphur Cycling in Marine Sediments: A Model Analysis
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The geochemical cycles of iron and sulphur in marine sediments are strongly intertwined and give rise to a complex network of redox and precipitation reactions. Bioturbation refers to all modes of transport of particles and solutes induced by larger organisms, and in the present-day seafloor, bioturbation is one of the most important factors controlling the biogeochemical cycling of iron and sulphur. To better understand how bioturbation controls Fe and S cycling, we developed reactive transport model of a coastal sediment impacted by faunal activity. Subsequently, we performed a model sensitivity analysis, separately investigating the two different transport modes of bioturbation, i.e. bio-mixing (solid particle transport) and bio-irrigation (enhanced solute transport). This analysis reveals that bio-mixing and bio-irrigation have distinct—and largely opposing effects on both the iron and sulphur cycles. Bio-mixing enhances transport between the oxic and suboxic zones, thus promoting the reduction of oxidised species (e.g. iron oxyhydroxides) and the oxidation of reduced species (e.g. iron sulphides). Through the reoxidation of iron sulphides, bio-mixing strongly enhances the recycling of Fe and S between their reduced and oxidised states. Bio-irrigation on the other hand removes reduced solutes, i.e. ferrous iron and free sulphide, from the sediment pore water. These reduced species are then reoxidised in the overlying water and not recycled within the sediment column, which leads to a decrease in Fe and S recycling. Overall, our results demonstrate that the ecology of the macrofauna (inducing bio-mixing or bio-irrigation, or both) matters when assessing their impact on sediment geochemistry. This finding seems particularly relevant for sedimentary cycling across Cambrian transition, when benthic fauna started colonizing and reworking the seafloor.
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No RBINS Staff publications
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The initial response of females towards congeneric males matches the propensity to hybridise in Ophthalmotilapia
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RBINS Staff Publications 2022 OA
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The internal division of the Pliocene Lillo Formation: correlation between Cone Penetration Tests and lithostratigraphic type sections
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RBINS Staff Publications 2020
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The introduction of the European fallow deer to the northern provinces of the Roman Empire: a multi-proxy approach to the Herstal skeleton (Belgium)
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Many exotic animal species were introduced to Northern Europe during the Roman period, including fallow deer (Dama dama). To date, however, finds of fallow deer bones at archaeological sites in this region have been sporadic and disarticulated, leaving uncertainty over their origins. This article presents the first known articulated fallow deer skeleton from Roman North-western Europe. Osteological, ancient DNA, radiocarbon dating and stable isotope analyses confirm that the species was established in this region by the Roman period, probably originating from translocated, rather than native, Mediterranean populations. Clarifying the origins of fallow deer in North-western Europe is critical for understanding the dynamics of species exchange around the Roman Empire.
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RBINS Staff Publications 2020
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The journals of the Société (Royale) Malacologique de Belgique (1863-1902): A history and collation
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RBINS Staff Publications 2021
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The key to bringing DNA collections to the next level
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DNA collections are a valuable type of Natural Science collection, enabling the validation of past research, serving as a source for new genomic studies and supporting ex situ conservation. The DiSSCo Flanders DNA collection working group, aiming to advance and "unlock" their DNA collections, identified the need for: 1) actively sharing best practices regarding the management of DNA collections; and 2) providing guidance on how to bring theory into practice. By combining best practice examples from within the working group with available literature and brainstorming ideas, the working group co-created two outputs, referred to as: the "Challenges" and the "Key". The Challenges are a list of obstacles to DNA collection management, which shape the structure of the linked Key and can also be used to spark discussion amongst stakeholders. The Key is a tool that guides users through the maturation process of their DNA collection in a standardised way. It stimulates holistic growth, breaks down the needed work into manageable steps and helps to decide priorities during the process. Furthermore, the Key facilitates communication with both internal stakeholders and external DNA collection managers. The Key distinguishes itself from other self-assessment tools in several ways: it includes (re)investigation of the collection’s purpose and context; it is specialised for DNA collections; it delivers concrete goals linked to relevant information and shared experience; and it is inclusive, targeting all Natural Science DNA collections, regardless of their context or size.
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RBINS Staff Publications 2024
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The Lanternflies (Hemiptera: Fulgoromorpha, Fulgoridae) of Khao Krachom Mountain, Thailand
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RBINS Staff Publications 2021
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The Lanternfly genus Pyrops in Vietnam: A new species from Central Vietnam, taxonomic changes, checklist, identification key (Hemiptera: Fulgoromorpha: Fulgoridae)
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RBINS Staff Publications 2022 OA
