Further records of a new diatom species in the English Channel and North Sea: the importance of image-referenced data

Alexandra C Kraberg,Rachel Beckett,Johannes Rick,Paul Rooks,Claire E Widdicombe,René Van Wezel

doi:10.1186/s41200-018-0155-0

Abstract

BackgroundIn September 2015, an at the time undescribed, autotrophic taxon was discovered in the western English Channel (station L4) and also in the eastern English Channel and Celtic Sea during the Polarstern Cruise PS95 a month later. Subsequent investigations revealed further extensive records (going back to 1992) at stations in the English Channel and the southern North Sea (e.g. Helgoland Roads and Sylt Roads time series stations). Stations in the Northern North Sea have not recorded this distinct taxon. With the available records and crucially, the accompanying image metadata, we are able to chart a clear distribution record with occurrences being restricted to the southern North Sea and English Channel.MethodsThe biological data shown are from Lugol-fixed Utermöhl counts and investigations of live and Formalin-fixed net hauls (20 μm mesh size). All image material shown is available in the online repository Planktonnet (http://planktonnet.awi.de).ResultsWe report the distribution, based on geo-referenced image records of an easily recognisable, yet taxonomically uncertain, autotrophic organism.ConclusionsDistribution patterns of the unidentified autotrophic taxon suggests entry of this taxon into/out of the North Sea via the English Channel. Further investigations providing image-documented information over several years is clearly necessary to clarify its dynamics and ecological characteristics.

Highlights

In September 2015, an at the time undescribed, autotrophic taxon was discovered in the western English Channel and in the eastern English Channel and Celtic Sea during the Polarstern Cruise PS95 a month later
Distribution data The earliest record documented by image material was from a cruise in the English Channel in 1992, where live material was taken by the Dutch monitoring agency within the framework of research on Harmful algal blooms (HAB) (Rademaker and Koeman 1992)
In the following years after 2012 this unclassified taxon has been reported by a number of time series stations in the English Channel, southern North Sea and the Dutch Wadden Sea

Summary

Introduction

In September 2015, an at the time undescribed, autotrophic taxon was discovered in the western English Channel (station L4) and in the eastern English Channel and Celtic Sea during the Polarstern Cruise PS95 a month later. Regular phytoplankton monitoring stations in the North Sea and English Channel possess detailed records of the taxa that have been observed there for at least 20 years (Hoppenrath 2004; Widdicombe et al 2010) These include the Western Channel Observatory‘s stations L4 and E1, stations along the Dutch coast, the Biologische Anstalt Helgoland with its Helgoland Roads long-term phytoplankton time series (located in the German Bight (Wiltshire et al 2010)) as well as the Wadden Sea station Sylt. These time series stations are ideally placed to chart differences in the dynamics and distribution of phytoplankton diversity in the English. We report a first distribution record, collated from multiple time series stations and cruises of Kraberg et al Marine Biodiversity Records (2018) 11:21 an organism for which the taxonomic identity is still under discussion but that can be identified reliably on the basis of its morphological characteristics based on photographic material available in a number of research stations

Methods

Results

Conclusion