Microbial community structure of sandy intertidal sediments in the North Sea, Sylt-Rømø Basin, Wadden Sea

Abstract. Phytoplankton form the base of the marine food chain, and knowledge of phytoplankton community structure is fundamental when assessing marine biodiversity. Policy makers and other users require information on marine biodiversity and other aspects of the marine environment for the North Sea, a highly productive European shelf sea. This information must come from a combination of observations and models, but currently the coastal ocean is greatly under-sampled for phytoplankton data, and outputs of phytoplankton community structure from models are therefore not yet frequently validated. This study presents a novel set of in situ observations of phytoplankton community structure for the North Sea using accessory pigment analysis. The observations allow a good understanding of the patterns of surface phytoplankton biomass and community structure in the North Sea for the observed months of August 2010 and 2011. Two physical–biogeochemical ocean models, the biogeochemical components of which are different variants of the widely used European Regional Seas Ecosystem Model (ERSEM), were then validated against these and other observations. Both models were a good match for sea surface temperature observations, and a reasonable match for remotely sensed ocean colour observations. However, the two models displayed very different phytoplankton community structures, with one better matching the in situ observations than the other. Nonetheless, both models shared some similarities with the observations in terms of spatial features and inter-annual variability. An initial comparison of the formulations and parameterizations of the two models suggests that diversity between the parameter settings of model phytoplankton functional types, along with formulations which promote a greater sensitivity to changes in light and nutrients, is key to capturing the observed phytoplankton community structure. These findings will help inform future model development, which should be coupled with detailed validation studies, in order to help facilitate the wider application of marine biogeochemical modelling to user and policy needs.

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Numerical modeling of physical processes in the North Sea and Wadden Sea with GETM/GOTM

NCK-days 2012 : Crossing borders in coastal research : jubilee conference proceedings ◽

10.3990/2.197 ◽

2012 ◽

Author(s):

Meinard Tiessen ◽

Janine Nauw ◽

Piet Ruardij ◽

Theo Gerkema

Keyword(s):

Numerical Modeling ◽

North Sea ◽

Wadden Sea ◽

Physical Processes ◽

The North ◽

The North Sea

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Sources and Fate of PCBs in the North Sea: A Review of Available Data

Water Science & Technology ◽

10.2166/wst.1991.0278 ◽

1991 ◽

Vol 24 (10) ◽

pp. 77-85 ◽

Cited By ~ 16

Author(s):

J. Klamer ◽

R. W. P. M. Laane ◽

J. M. Marquenie

Keyword(s):

Adverse Effects ◽

North Sea ◽

German Bight ◽

Marine Mammals ◽

Wadden Sea ◽

Annual Basis ◽

The North ◽

Total Input ◽

Seal Population ◽

The North Sea

From literature data it is calculated that on an annual basis, 11 to 17 tonnes of PCBs enter the North Sea. Largest sources are the Atlantic Ocean and the atmosphere: together they account for 60-79% of the total input. Sources with greatest impact are the rivers, sewers and sludge. Highest concentrations are found close to the Dutch shore and in the German Bight. The PCB levels result in adverse effects on the seal population in the Wadden Sea. Of the total world PCB production, at least 57% is still in use and their future dispersal into the oceans cannot easily be controlled. If the increase in ocean PCB concentration continues, it may ultimately result in the extinction of fish-eating marine mammals.

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Thalassiosiraspecies (Bacillariophyceae, Thalassiosirales) in the North Sea at Helgoland (German Bight) and Sylt (North Frisian Wadden Sea) – a first approach to assessing diversity

European Journal of Phycology ◽

10.1080/09670260701352288 ◽

2007 ◽

Vol 42 (3) ◽

pp. 271-288 ◽

Cited By ~ 31

Author(s):

Mona Hoppenrath ◽

Bank Beszteri ◽

Gerhard Drebes ◽

Hannelore Halliger ◽

Justus E. E. Van Beusekom ◽

...

Keyword(s):

North Sea ◽

German Bight ◽

Wadden Sea ◽

The North ◽

The North Sea ◽

North Frisian

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High-resolution analysis of a North Sea phytoplankton community structure based on in situ flow cytometry observations and potential implication for remote sensing

Biogeosciences ◽

10.5194/bg-12-4051-2015 ◽

2015 ◽

Vol 12 (13) ◽

pp. 4051-4066 ◽

Cited By ~ 22

Author(s):

M. Thyssen ◽

S. Alvain ◽

A. Lefèbvre ◽

D. Dessailly ◽

M. Rijkeboer ◽

...

Keyword(s):

Flow Cytometry ◽

Community Structure ◽

North Sea ◽

High Frequency ◽

Phytoplankton Community ◽

Phytoplankton Community Structure ◽

The North ◽

The North Sea ◽

Daily Scale

Abstract. Phytoplankton observation in the ocean can be a challenge in oceanography. Accurate estimations of its biomass and dynamics will help to understand ocean ecosystems and refine global climate models. Relevant data sets of phytoplankton defined at a functional level and on a sub-meso- and daily scale are thus required. In order to achieve this, an automated, high-frequency, dedicated scanning flow cytometer (SFC, Cytobuoy b.v., the Netherlands) has been developed to cover the entire size range of phytoplankton cells whilst simultaneously taking pictures of the largest of them. This cytometer was directly connected to the water inlet of a PocketFerryBox during a cruise in the North Sea, 08–12 May 2011 (DYMAPHY project, INTERREG IV A "2 Seas"), in order to identify the phytoplankton community structure of near surface waters (6 m) with a high spatial resolution basis (2.2 ± 1.8 km). Ten groups of cells, distinguished on the basis of their optical pulse shapes, were described (abundance, size estimate, red fluorescence per unit volume). Abundances varied depending on the hydrological status of the traversed waters, reflecting different stages of the North Sea blooming period. Comparisons between several techniques analysing chlorophyll a and the scanning flow cytometer, using the integrated red fluorescence emitted by each counted cell, showed significant correlations. For the first time, the community structure observed from the automated flow cytometry data set was compared with PHYSAT reflectance anomalies over a daily scale. The number of matchups observed between the SFC automated high-frequency in situ sampling and remote sensing was found to be more than 2 times better than when using traditional water sampling strategies. Significant differences in the phytoplankton community structure within the 2 days for which matchups were available suggest that it is possible to label PHYSAT anomalies using automated flow cytometry to resolve not only dominant groups but also community structure.

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