In the past, the dog whelk Nucella lapillus (Mollusca, Gastropoda, Muricidae) used to be a common species on jetties and groynes along the Belgian coast. During the seventies, the species became increasingly rare and the last Belgian specimen observed in situ was found in 1981. The extinction of the species is attributed to the use of paintings containing tributyltin (TBT) on the hulls of ships as antifouling protection. TBT dilutes in seawater and, even at extremely low concentration, sterilizes dog whelks. Since 1990, the use of Tributyltin (TBT) was restricted to ships smaller than 25 m; in 2003, it was totally forbidden and in 2008 old TBT paintings had to be removed from ship hulls. As a consequence the concentration in TBT of seawater presumably decreased in Belgian waters. On November 17th, 2012, several living adult dog whelks and 40 to 50 spawns ofthat species were observed on the concrete blocks of the western jetty of Zeebrugge harbour, indicating recolonization of the species in Belgium at least in one locality.
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Urbanization is one of the major causes of the destruction of natural habitats in the world. Cities are urban heat islands and can thus significantly influence populations of plants and animals. The research project SPEEDY investigated the effects of urbanization in northern Belgium with a nested sampling design at local and landscape scales for a variety of organisms. Here, we tested the effects of urbanization on non-marine ostracod communities, sampling 81 small pools in three urbanization categories, as defined by percentage built up cover (low, intermediate, high). We identified 17 ostracod species, together occurring in 60 of the 81 sampled pools. We found that urbanization per se had no significant effect on ostracod communities. Of all the measured local factors, ammonium and total phosphorus concentrations had a significant effect on the community structure. In contrast, water temperature had no significant effect, most likely because the ostracod species found in northern Belgium in the present survey mostly have wide temperature tolerances.
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RBINS Staff Publications 2021
pThis paper describes a prototype network of automated italicin situ/italic measurements of hyperspectral water reflectance suitable for satellite validation and water quality monitoring. Radiometric validation of satellite-derived water reflectance is essential to ensure that only reliable data, e.g., for estimating water quality parameters such as chlorophyll italica/italic concentration, reach end-users. Analysis of the differences between satellite and italicin situ/italic water reflectance measurements, particularly unmasked outliers, can provide recommendations on where satellite data processing algorithms need to be improved. In a massively multi-mission context, including Newspace constellations, hyperspectral missions and missions with broad spectral bands not designed for “water colour”, the advantage of hyperspectral over multispectral italicin situ/italic measurements is clear. Two hyperspectral measurement systems, PANTHYR (based on the mature TRIOS/RAMSES radiometer) and HYPSTAR$^®$ (a newly designed radiometer), have been integrated here in the WATERHYPERNET network with SI-traceable calibration and characterisation. The systems have common data acquisition protocol, data processing and quality control. The choice of validation site and viewing geometry and installation considerations are described in detail. Three demonstration cases are described: 1. PANTHYR data from two sites are used to validate Sentinel-2/MSI (A&B); 2. HYPSTAR$^®$ data at six sites are used to validate Sentinel-3/OLCI (A&B); 3. PANTHYR and HYPSTAR$^®$ data in Belgian North Sea waters are used to monitor phytoplankton parameters, including italicPhaeocystis globosa/italic, over two 5 month periods. Conclusion are drawn regarding the quality of Sentinel-2/MSI and Sentinel-3/OLCI data, including indications where improvements could be made. For example, a positive bias (mean difference) is found for ACOLITE\_DSF processing of Sentinel-2 in clear waters (Acqua Alta) and clues are provided on how to improve this processing. The utility of these italicin situ/italic measurements, even without accompanying hyperspectral satellite data, is demonstrated for phytoplankton monitoring. The future evolution of the WATERHYPERNET network is outlined, including geographical expansion, improvements to hardware reliability and to the measurement method (including uncertainty estimation) and plans for daily distribution of near real-time data./p
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RBINS Staff Publications 2025
