Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Meteor	M174	12.04.2021 - 30.05.2021	MENARP	Tropical NW Atlantic Atlantic Ocean

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Voss Maren	Leibniz-Institut fur Ostseeforschung, Warnemunde	Las Palmas	Emden

Ziel der Reise / Objectives of Cruise:

OBJECTIVE: The purpose of the cruise was to provide for the first time a comprehensive overview over nitrogen cycling processes in surface waters combined with in-depth physical process measurements on mixing and stratification. Moreover, the transfer of nitrogen from different food sources into higher tropic levels such as zooplankton, fish larvae, and gelatinous species will be evaluated. We hypothesize that the water properties and nitrogen fluxes vary significantly across zones with decreasing plume impact when moving from the river mouth north and northwest. SUMMARY: Work on the shelf off the Amazon estuary and in the western tropical North Atlantic was conducted around the clock for a total of 23 days to comprehensively analyze the nitrogen cycle, physical processes, and food webs. Thirty-two stations were worked, including five long-term stations with drifters, and six Scanfish transects were run. Station selection, supported by satellite imagery of the extent of the river plume, ensured that we could capture different developmental stages of plankton communities. A preliminary classification based on the data collected on board allows us to distinguish at least 4 zones - one near the mouth of the Amazon River with pronounced influence of freshwater and sediment loads, the second zone with higher salinities but in a shallow distinct surface layer, a third zone with much stronger mixing of Atlantic water and already depleted in nutrients, and a fourth zone showing only slightly lower salinities and apparently relying on nutrient supply from nitrogen fixers. Details of nitrogen turnover in these zones and transfer to mesozooplankton will be revealed by data from the many incubation experiments being analyzed in the laboratories.

Messungen / Measurements

Verankerungen / Moorings