METEOR M147

The Amazon river estuary is the main work area of cruise M147 (20 April – 20 May 2018). The scientific goal is to determine in detail the distribution and speciation of trace elements along the salinity gradients in the mixing zone of the Amazon estuary and its freshwater plume, in order to quantify their biogeochemical cycling and their interaction with Dissolved Organic Material (DOM) and particulate matter. This includes assessing the role of the Amazon for the input of trace metals and DOM into the Atlantic and understanding the interactions between trace metals and DOM which can be assumed to enhance the trace metal flux to the ocean due to competition with colloidal coagulation and sedimentation. Another important factor to be considered is trace metal associations with different pools (truly dissolved, organic colloids, inorganic colloids, particles) with increasing salinity along mixing transects between river and ocean endmembers. The cruise is part of the internationally coordinated programme GEOTRACES. Chief scientist is Andrea Koschinsky of the Jacobs University Bremen. The first nine days of the cruise (20 – 28 April 2018) are used for a transect across the Atlantic from Las Palmas (Canary Islands, Spain) to Belem (Brazil) with regular water sampling. During this time, Martin Frank (GEOMAR) acts as chief scientist.