Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Heincke	HE516	17.07.2018 - 16.08.2018		NW Atlantic (Limit 40?W)

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Krock Bernd	Alfred-Wegener-Institut fur Polar- und Meeresforschung	Bremerhaven	Bremerhaven

Ziel der Reise / Objectives of Cruise:

The main objectives of the cruise were: 1) to define the specific hydrographic and/or meteorological conditions responsible for recurrent AZP along Irish coasts 2) to quantitatively determine the spatial distribution of species of Amphidomataceae and the corresponding toxins in the plankton. Pattern and potential gradients in distribution will provide evidence for or against the hypothesis that that toxigenic Amphidomataceae are drifted from the open sea to coastal areas of Ireland. 3) to characterize the plankton communities accompanying Amphidomatacean species. Together with toxin analysis of size fractionated samples and manually sorted grazers species, and using existing plankton data of the Marine Institute it is aimed to identify heterotrophic dinoflagellates, ciliates, or other small zooplankton as not yet recognized toxin vectors 4) to assess the distribution of Amphidomatacean resting stages along the Irish coastline to evaluate the hypothesis that extended cyst beds are responsible for recurrent Azadinium blooms in Irish coastal area. 5) to link hyperspectral light availability and bio-optical environment with local phytoplankton distribution incorporating the topography and hydrodynamic conditions in an attempt to explain patchiness and bloom favouring conditions. 6) to investigate the light climate to address changes in light availability (coastal ocean darkening) with consequences for primary producers, biodiversity and marine and coastal ecosystems. A comparison with earlier studies around Ireland is possible (e.g. HE302). 7) to complete data sets from the Southern and (North-) Western North Sea obtained during earlier expeditions for site comparison over the years. The survey started on the 17th July, 20.00 h eight hours late because the luggage of the Irish colleagues, who had arrived at Bremerhaven the day before, was delivered at Bremen Airport with a delay of 24 hours. R/V departed Heincke from the AWI pier in Handelshafen, where all scientific equipment had been taken on board previously and the first station was successfully completed the next morning at Borkum Riff in order to test all equipment and to conduct limited instrument trials. Bio-optical measurements were performed without any difficulties, whereas phytoplankton sample work-up and aliquotation proved to be difficult due to high biomass and sediment concentrations. However, these problems ceased with the following stations. followed by another station in the southern North Sea on the same day. In continuation, two stations per day were sampled in the British Channel until the western tip of Cornwall, form where a denser sampling regime through the Celtic Sea with three stations per day towards the southern Irish coast was applied. Here began the first transect perpendicular to the Irish coast. The further course went along the Irish coast first to the west and later to the north including two more perpendicular transects, one to the south and another in southwest direction from Bantry Bay. Weather became stormier towards the end of the month and the Captain Diecks decided to shelter one day in the bay of Galway on the 31st July due to bad weather conditions. In the morning of 1st August the port of Galway was reached and the Irish crew was exchanged. In calmer weather, the expedition continued 2nd August along the Irish coast including two further perpendicular transects to the west north of Galway and to the northwest from Donegal Bay. The survey continued further north passing the Outer Hebrides in the west and further along the north coast of Scotland through the Pentland Firth into the North Sea. Unexpectedly the sea was extraordinarily calm throughout the complete second leg of the survey, which permitted to maintain the sampling regime of three stations per day. The North Sea was sampled in a straight line from Pentland Firth to Helgoland and continued further to Bremerhaven, which was reached on the morning of 15th of August.

Messungen / Measurements