Ecological long-term research at Helgoland (German Bight, North Sea): retrospect and prospect?an introduction

Franke, Heinz-Dieter; Búchholz, Friedrich; Wiltshire, Karen Helen

doi:10.1007/s10152-004-0197-z

Cited by 36 publications

(14 citation statements)

References 19 publications

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“…The water depth varies from 6-8 m in depth depending on the tide. Further information about this site can be found in Franke et al (2004) and Wiltshire et al (2010). Sampling for phytoplankton began at this site in 1962.…”

Section: Long-term Monitoring Sitesmentioning

confidence: 99%

Diversity and seasonality of Pseudo-nitzschia (Peragallo) at two North Sea time-series monitoring sites

et al. 2015

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Species within the diatom genus Pseudo-nitzschia (Peragallo) have been identified as producers of domoic acid, the toxin responsible for amnesic shellfish poisoning. Toxin-and non-toxin-producing species of Pseudo-nitzschia have been reported globally; however, as Pseudo-nitzschia species cannot be routinely identified to species level using light microscopy, cells are rarely recorded to species level during long-term monitoring studies. Here, we report the results of a comparative survey of Pseudo-nitzschia species at two monitoring sites in the North Sea: Stonehaven on the east coast of Scotland and Helgoland Roads in the German Bight. A difference in the seasonality of this genus was observed between the sites with Pseudo-nitzschia cells playing a major role in the spring bloom as well at the summer and autumn diatom community at Stonehaven. In contrast, Pseudo-nitzschia was abundant only during the summer months at Helgoland. Pseudo-nitzschia cells constitute a higher proportion of the diatom community at Stonehaven than at Helgoland, particularly during the late summer, autumn and winter and thus may be considered more 'ecologically important' at this site. A total of eight different species were recorded during this survey with five Pseudo-nitzschia species observed at the Helgoland site: P. pungens, P. fraudulenta, P. americana, P. cf. delicatissima and the potentially toxic species P. multiseries. Six species were also recorded at Stonehaven; P. australis, P cf. delicatissima, P. pungens, P. cf. pseudodelicatissima, P. subpacifica and P. seriata. This study represents the first examination of the seasonality of Pseudo-nitzschia species around Helgoland and the first comparison between two long-term monitoring sites in the North Sea. P. americana and P. multiseries are also recorded at the Helgoland Roads time-series site for the first time.

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Section: Long-term Monitoring Sitesmentioning

confidence: 99%

Diversity and seasonality of Pseudo-nitzschia (Peragallo) at two North Sea time-series monitoring sites

et al. 2015

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“…The sampling site at Helgoland Roads (54°11.3 0 N; 7°54.0 0 E) is situated between the main island of Helgoland and the dune island west of it. Surface water samples were taken three times per week until 1974 and five times per week thereafter (Franke et al 2004). Since the water column is generally well-mixed by hydrographical forcing, surface water may be regarded as representative of the entire water column (Hickel 1998).…”

Section: Helgoland Roads Datamentioning

confidence: 99%

Changes in the phytoplankton community at Helgoland, North Sea: lessons from single spot time series analyses

et al. 2012

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In recent regime shift analyses, the phytoplankton compartment of the marine food web was essentially represented by phytoplankton color or chlorophyll concentration. A detection of changes directly at the species level is highly desirable. The Helgoland Roads data series, a collection of high frequency long-term time series comprising biological and physico-chemical components of the southern North Sea, allow such an investigation at the level of single species. Aiming at a detection and characterization of habitat and community changes in the observation period (1962 until the end of 2008), we selected six species as representatives of certain classes, for example, benthic or neritic species, and applied a combination of novel analysis methods-a fitness-based analysis of the realized niche, a bloom-triggered averaging and a Markovian analysis of co-occurrence and succession patterns-to related abundance time series and concurrent environmental parameter time series. We found a general trend toward enlargement of niche size and shifts of the niche position, interesting salinity patterns around bloom events of two species, and statistically highly significant changes of a phytoplankton community segment after 1965 and after 1998. Interpreting our observations in ecological terms leads to the formulation of testable hypotheses.

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“…With the logistic support of the Institute, the initial mark-recapture programme will be continued on the basis of the tagged lobsters which are still out in the field. The data will be integrated into the ongoing long term ecological observation programmes of the benthic and pelagic biotic and abiotic environment at Helgoland (Franke et al, 2004).…”

Section: Growth Conditions Of Hatchery-reared Lobstersmentioning

confidence: 99%

A mark-recapture study of hatchery-reared juvenile European lobsters, Homarus gammarus, released at the rocky island of Helgoland (German Bight, North Sea) from 2000 to 2009

et al. 2011

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a b s t r a c tFrom 2000 to 2005 about 5400 one-year-old hatchery-reared lobsters (Homarus gammarus) were tagged and released at the rocky island of Helgoland, North Sea. To date, 1-8% of the different release cohorts were recaptured in the field and 8-19% of these lobsters were recaptured from the semi-open area of the outer harbour. The recaptured lobsters indicated good development and growth conditions. The smallest berried females caught were 83 mm carapace length and 4 years old. The proportion of cultured lobsters to all measured lobsters captured around the island was 3-8% in the years [2007][2008][2009]. The population size of two cohorts was assessed using the Lincoln-Peterson method and the estimated survival rate averaged 30% and 40%. Minimum landing size of cultured lobsters was reached after 4-7 years. Cultured lobsters showed strong fidelity to their release sites, and thus remained around the island of Helgoland. A basis has been laid to enhance this endangered lobster population by means of a large scale restocking programme.

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Ecological long-term research at Helgoland (German Bight, North Sea): retrospect and prospect?an introduction

Abstract: This paper summarizes and evaluates ecological long-term observations at the island of Helgoland

Cited by 36 publications

References 19 publications

Diversity and seasonality of Pseudo-nitzschia (Peragallo) at two North Sea time-series monitoring sites

Diversity and seasonality of Pseudo-nitzschia (Peragallo) at two North Sea time-series monitoring sites

Changes in the phytoplankton community at Helgoland, North Sea: lessons from single spot time series analyses

A mark-recapture study of hatchery-reared juvenile European lobsters, Homarus gammarus, released at the rocky island of Helgoland (German Bight, North Sea) from 2000 to 2009

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