Helgoland Roads Phytoplankton time series

The Helgoland Roads time series is one of the richest temporal marine data sets available. It includes daily surface water sampling from 1962 until present, resulting in a pelagic data set comprised of phytoplankton, salinity, Secchi and nutrient analyses. The pelagic time series are augmented by the biological parameters such as zooplankton, rocky shore macroalgae, macro-zoobenthos and bacteria. Until recently it was quite difficult to interpret the Helgoland long term data. This was due to a lack of meta-information and quality control which has now been rectified. These data sets are presented and examples of the major changes from bacteria, phytoplankton through to macro-benthos at Helgoland are given. The hydrographic environment around Helgoland is analysed and shown to have changed considerably. With changes in currents, in the late 1970's, water inflows from the southwest to the German Bight increased and corresponding flushing rates increased by nearly 30%. These conditions prevailed for 15 years. The salinity at Helgoland Roads shows an increase from 1962 to the present. The annual mean temperature in the surface water at Helgoland Roads has risen significantly by a mean value of 1,67oC since 1962. We show that temperature has influenced the seasonal growth of phytoplankton, i.e. the number of "growth" days for phytoplankton have extended significantly. There was a significant shift in diatom densities and in the numbers of large diatoms (eg. Guinardia delicatula and Coscinodiscus wailesii) which are difficult for copepods to graze. Large shifts in zooplankton diversity were observed with the input of Mnemiopsis leidyi being the most obvious new species. Losses and additions to the macroalgal flora were identified for the last 100 years, but macroalgal species richness has not changed. The number of green algal species has increased and the number of brown algal species has decreased after 1959.More than 30 macrofaunal species have been newly recorded at Helgoland Roads over the last 20 years. There has been a distinct shift in benthic animals towards southern species and an increase in local species diversity. From the data on the seasonality of bacteria through to investigations into changes in macrofauna, we provide the basis for long term analyses of changes on many trophic levels at Helgoland Roads.

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Data and Resources

Additional Info

Field Value
Geographic coverage
Geographic description Helgoland Roads: A small channel between the Düne and the main island of Helgoland, located in the German Bight, North Sea, approximately 60 km from the mainland
Bounding coordinates
North: 54.1831
West: 7.9
East: 7.9
South: 54.1831
Temporal coverage
Timestep 1962
Taxonomic coverage
Species Phytoplanktion
General taxonomic description Samples are identified to species level where necessary, where this is not possible, size classes are used.
Other info
Last Updated February 10, 2021, 14:20 (UTC)
Created February 10, 2021, 14:20 (UTC)

Responsible parties

Name Karen Wiltshire
Organization affiliations
Alfred-Wegener Institute for Polar and Marine Research, Biological Station Helgoland

Kurpromenade, 201
27498 Helgoland


Name Alexandra Kraberg
Organization affiliations

Associated party
Name Karen Wiltshire

Research data management planning

Data will be stored at (long-term archived) Information still missing

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