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Papers by Katja Philippart

Kader Advies op verzoek van Rijkswaterstaat Noord-Nederland n.a.v. het containerverlies door de M... more Kader Advies op verzoek van Rijkswaterstaat Noord-Nederland n.a.v. het containerverlies door de MSC Zoe in januari 2019 Te refereren als Philippart, K., L. Hanssen & J. van Dijk (2019) Wat zijn de gevolgen van de door de MSC Zoe verloren lading voor de Noordzeekustzone en de Waddenzee? Onderzoeks-en monitoringplan voor de korte-en langetermijngevolgen van microplastics voor het Waddengebied en haar bewoners. Position Paper 2019-01. Waddenacademie, Leeuwarden. Grafisch ontwerp BW H ontwerpers Foto omslag Arnold van der Wal

Seasonal cycles o f salinity, nutrients, chlorophyll and Zooplankton at 8 locations on the W est-... more Seasonal cycles o f salinity, nutrients, chlorophyll and Zooplankton at 8 locations on the W est-European shelf were analysed with respect to their tim ing and m agnitude in the period 1980-1984. A late spring bloom with low chlorophyll values (2-4 m g.m '3) is observed in the Irish Sea, off the Scottish east coast and the Channel entrance. An early spring bloom and relatively high chlorophyll values (7-12 m g.m '3) are found in the southern Bight and the Skagerrak, whereas a late spring bloom with high chlorophyll concentrations (24 m g.m '3) is found along the Dutch and Belgian coast. In contrast to the other regions, the peak o f the phytoplankton cycle in the Germ an B ight (H elgoland) occurs in the sum m er period instead o f the spring period. The peak in the yearly abundance of copepods shifts from M ay-June in the south to July-A ugust in the north o f the shelf. In the Irish Sea and the C hannel entrance two seasonal copepods peaks are observed. The January nitrate values in Irish Sea, the southern B ight and the Skagerrak are about 20 % higher than those in the Atlantic input signal in the Channel entrance and east off Scotland. The January D IP values in these regions are com parable to those of the input signal, but the Irish Sea form s an exception here the level is increased by 10-20%. If compared with the Atlantic input signal the January values for nitrate and DIP at the D utch and Belgium coast are about 10 and 4, and in the German Bight This paper has been submitted to Deutsche Hydrographische Zeitschrift as part of a special issue on NOWESP NOWESP Final Report Bot ef al. (H elgoland) 4 and 3 times higher, respectively. A t most sites changes in the seasonal cycles o f chlorophyll coincide with changes in nutrient concentrations, whereas the m axim um level o f the seasonal signal is related to the nutrient levels.

Culture studies of microorganisms have shown that the hydrogen isotopic composition of fatty acid... more Culture studies of microorganisms have shown that the hydrogen isotopic composition of fatty acids depends on their metabolism, but there are only few environmental studies available to confirm this observation. Here we studied the seasonal variability of the deuterium/hydrogen (D/H) ratio of fatty acids in the coastal Dutch North Sea and compared this with the diversity of the phyto-and bacterioplankton. Over the year, the stable hydrogen isotopic fractionation factor ε between fatty acids and water ranged between-172 ‰ and-237 ‰, the algal-derived polyunsaturated fatty acid nC20:5 being the most D-depleted and nC18:0 the least D-depleted fatty acid. The D-depleted nC20:5 is in agreement with culture studies, which indicates that photoautotrophic microorganisms produce fatty acids which are significantly depleted in D relative to water. The εlipid/water of all fatty acids showed a transient shift towards increased fractionation during the spring phytoplankton bloom, indicated by increasing chlorophyll a concentrations and relative abundance of the nC20:5 PUFA, suggesting increased contributions of photoautotrophy. Time periods with decreased fractionation (less negative εlipid/water values) can be explained by an increased contribution by heterotrophy to the fatty acid pool. Our results show that the hydrogen isotopic composition of fatty acids is a useful tool to assess the community metabolism of coastal plankton.

The strong decline in Wadden Sea fish since the 1980s has called for action to strengthen local d... more The strong decline in Wadden Sea fish since the 1980s has called for action to strengthen local diadromous fish stocks. A recent explanatory study showed that most promising potential measures to strengthen local fish stocks and other natural values of this region include reduction of fishing efforts, provisioning of suitable habitats (such as brackish zones) and facilitation of fish migration. Reduction of shrimp fishing in the Wadden Sea would decrease mortality of diadromous fish (4 million per year), and be beneficial for additional natural values of the Wadden Sea (e.g. mussel beds, birds, seals). Reduction of fishing activities for Eel and Smelt in the adjacent Lake IJssel would favour local fish stocks, and also enhance the supply of fish (e.g. Smelt) to Wadden Sea stocks. Estuarine gradients in the Wadden Sea vary from small tidal creeks at the islands to large freshwater sluices along the mainland coast. Present natural estuarine gradients should be safeguarded and, if nece...

VLIZ Special Publication, 2011

Vlaams Instituut voor de Zee. VLIZ. Informatie over marien en kustgebonden onderzoek & beleid in ... more Vlaams Instituut voor de Zee. VLIZ. Informatie over marien en kustgebonden onderzoek & beleid in Vlaanderen.

VLIZ Special Publication, 2007

NIOZ jetty (LON=4.789E, LAT=53.002N) Marsdiep biological time series. 40 samples a year, weekly i... more NIOZ jetty (LON=4.789E, LAT=53.002N) Marsdiep biological time series. 40 samples a year, weekly in growing season, biweekly outside of growing season. Secchi depth and bucket sample of surface water at high tide (North Sea waters) with subsequent analysis of T, S, TSM, TP, PO4, NO3, NO2, NH4, Si, DIC, Chla.

VLIZ Special Publication, 2011

VLIZ Special Publication, 2007