Records of five bryozoan species from offshore gas platforms rare for the Dutch North Sea

This study reports on bryozoan species collected at three offshore gas platforms in the Dutch part of the North Sea. Four out of thirteen observed species are considered as rare in the Netherlands, whereas Cribrilina punctata is anew species for Dutch waters

Fouling community composition on a pilot floating solar-energy installation in the coastal Dutch North Sea

The increasing need for renewable energy has led to the transition of renewable energy devices to the marine environment. Currently, mainly offshore wind farms have been completely developed and are operational in the North Sea. The solar energy sector is also rapidly evolving and floating photovoltaics are continuously created and deployed. In this study, we investigated the colonisation patterns and community changes with time of fouling fauna on the first floating photovoltaics in the coastal Dutch North Sea. Samples were collected by divers from the underwater side of 4 floaters, coated with different anti-fouling techniques (Intersleek, GreenPowerNano PPDura, Finsulate and Pato) at two different moments, shortly after the deployment of the floaters and approximately a year later. In total, 72 fouling taxa were identified on the floaters, from which ca. 11% are known to be non-indigenous species for the region. The anti-fouling coating Intersleek seemed to work the most efficiently against fouling colonisation, since the fouling community sampled from this floater contained the least taxa. However, the small number of samples collected from the different floaters did not allow for a direct comparison between the anti-fouling coatings. The communities evolved with time, with young communities accommodating a larger number of individuals and old communities having less individuals but higher biomass, indicating that the organisms become bigger in size and compete for the available space. Nevertheless, the communities had not reached a stable climax yet, while this process might take multiple years due to the dynamic environment in which floating photovoltaics are deployed. Monitoring the fouling communities occurring on floating photovoltaics in the North Sea for a long-term is necessary to understand the effects of these new man-made structures on the marine environment, especially since floating photovoltaics are moving to offshore locations and will be possibly co-located with offshore wind farms in the future

Ecologische effecten van MSC Zoe polystyreen-korrels onderzocht in experimentele marine ecosystemen

Begin januari 2019 verloor containerschip MSC Zoe ten noorden van de Waddeneilanden een deel van haar lading. Naast ander materiaal, kwamen hierbij microplastics in zee terecht in de vorm van ca. 5 mm grote high density polyethylene (HDPE)-pellets en ca. 0.5 mm grote polystyreen (PS)-korrels. In opdracht van RWS-NN is door Wageningen Marine Research onderzoek in outdoor mesocosms uitgevoerd naar de ecologische effecten van de PS-korrels. De mesocosms werden ingericht met in de Waddenzee voorkomende ongewervelden en met juveniele platvis (tong). Na de toevoeging van een concentratiereeks van 0.1, 0.8, 8.0 en 80 gram PS-korrels per m2 werd de ontwikkeling van de organismen en ecosysteem in de mesocosms gedurende 56 dagen gevolgd. Er ontstonden verschillende effecten na de dosering van de PS-korrels. Statistisch significant waren: • een eenmalig lagere dichtheid copepoden, de dominante zoöplankton groep, in de 80 g/m2 mesocosms; • lagere dichtheden zeepokken vanaf 0.8 g/m2; • hogere dichtheid van schelpdieren en wormen in de 0.8 g/m2 mesocosms voor een deel van de soorten gevolgd door een afname bij hogere concentraties; • een hogere dichtheid van de wormen Spionidae sp. in de 80 g/m2 mesocosms; • een iets hoger vleesgewicht van mosselen in de 80 g/m2 mesocosms; • een iets lagere conditie factor van de tong uit de 0.8 g/m2 en de 80 g/m2 mesocosms. De hogere dichtheden van schelpdieren en wormen in de 0.8 g/m2 mesocosms is mogelijk het gevolg van verminderde begrazingsdruk op hun larven door zeepokken. De biodiversiteit in de mesocosms werd hierdoor niet beïnvloed. In de laagste testconcentratie (0.1 g/m2) werden in de mesocosms geen statistisch significante afwijkingen van de blanco’s gevonden. Dit kwam overeen met 326 PS-korrels per m2, en het scenario dat alle door MSC Zoe verloren PS-korrels zich homogeen verspreid hebben over 10% (ca. 15.000 ha) van het oppervlak van de Nederlandse Waddenzee. Hogere onderzochte concentraties, vanaf 3.260 korrels per m2 (0.8 g/m2), veroorzaakten wel significante effecten op zeepokken, bodemfauna en juveniele platvis (tong). Tot en met de hoogst geteste concentratie van meer dan 300.000 korrels per m2 bleef de omvang van de effecten beperkt. Pelagische plankton-etende vis is in deze studie niet onderzocht. Het risico voor vissen als geheel is hierdoor mogelijk onderschat, omdat plankton-etende vis wellicht minder goed kunnen omgaan met onverteerbare ingeslikte (plastic) deeltjes dan bodemvissen die gewend zijn ook schelpen en zand in te slikken

Benthic development around a gas platform in the North Sea -: a small scale closure for fisheries : a trait based approach

This project looked at the effect of closing an area for fisheries on the development of the benthic community. An existing data set of benthic species densities sampled at different distances and angles from a platform was used for this purpose. The particular area was closed due to the installation of a gas production platform, but is likely to function as a marine protected area (MPA), with the expectation that the benthic community develops differently from the benthic community in the surrounding areas as it no longer has to cope with the impact of fisheries. Differences in development might be linked to the impact of fisheries and the effects of closure might provide an expectation for the effect of planned MPAs in similar areas

Subtle ecosystem effects of microplastic exposure in marine mesocosms including fish

For two months, communities in 5.8 m3 outdoor marine mesocosms were exposed to 700 μm sphere-shaped polystyrene (PS) beads in dosages between 0.08 and 80 g/m2 . Barnacle (Semibalanus balanoides) densities were reduced at dosages of 0.8 g/m2 onwards without following a standard dose response curve. Lugworms and fish (Solea solea) ingested PS-beads without accumulating them. Lugworms (Arenicola marina) ingested the beads nonselective with the sediment without negative effects. The fish seemed to ingest the plastics only occasionally and at the final sampling day even in the highest dosed mesocosms (>30 beads/cm2) only 20% contained plastic. The condition index of the fish was slightly reduced in mesocosms with dosages of 0.8 g/m2 onwards. No difference in condition was found between fish with and without ingested plastic across mesocosms, illustrating the difficulty to relate plastic ingestion with condition from field data. The fish also ingested mollusks with shells exceeding the size of the PS-beads. Bivalves rejected the PS-beads as pseudofeces, without obvious impact on their condition. Mussel’s (Mytilus edulis) pseudofeces present an effective matrix to monitor microplastic presence in the water column. Species richness and diversity of the pelagic and benthic community were not affected although, a trend was found that the lower microplastic dosages had a positive effect on the total abundance of benthic invertebrates. In general, the observed effects at even the highest exposure concentrations were that subtle that they will be obscured by natural variation in the field. This underlines the importance of experiments under semi-field conditions for meaningful assessment of the ecological impact of microplastics. This study was performed with the real life, non-toxic, sphere-shaped polystyrene beads as were lost during an actual spill near the Dutch Wadden sea in January 2019. We recommend future mesocosm studies with other types of microplastics, including microfibers, weathered microplastics from sea, and smaller sized particles down to nanoplastics

First record of Harmothoe aspera (Hansen, 1879) (Polychaeta: Polynoidae) in the Dutch North Sea

Harmothoe aspera has been recorded in surveys off the Strait of Georgia, the Skagerrak, and the Barents, Mediterranean and Japanese sea. The recorded depth ranged from circa 48 m to circa 1500 m. This is the first report of H. aspera in the Dutch Exclusive Economic Zone (EEZ), and the first report in a depth range between15 and 20 m

First record of Harmothoe aspera (Hansen, 1879) (Polychaeta: Polynoidae) in the Dutch North Sea

Abstract Harmothoe aspera has been recorded in surveys off the Strait of Georgia, the Skagerrak, and the Barents, Mediterranean and Japanese sea. The recorded depth ranged from circa 48 m to circa 1500 m. This is the first report of H. aspera in the Dutch Exclusive Economic Zone (EEZ), and the first report in a depth range between 15 and 20 m

DATASET

CSV containing raw sampling data including date and position, among others

First record of Syllis vittata (Polychaeta: Syllidae) in the Dutch North Sea

Background: Syllis vittata is present from British Waters to the Mediterranean Sea, Morocco and the Canary Islands and recorded from the South African coast and Indian Ocean.Results and conclusion: In this paper, S. vittata is reported for the first time in the Dutch EEZ