Deployment: KOK1115

BAG EM UP (Biogeochemistry and Genomes (BAG-1) Mesocosm Experiment: Experimental

Long term ocean ecology characterization is predicated on a variety of in situ shorter term experiments and field exercises. These shorter term experiments can be generally classed in one of two ways. The first way of approach is to observe or capture physical or biogeochemical ocean events that are short term in duration or in location. We would consider the use of the research vessel or autonomous vehicle, or sediment trap part of this first approach. The second type of experiment is also an in situ approach, where one perturbs a “subset” of the natural ecosystem by manipulating or isolating various features (and/or processes) to test a hypothesis. This is illustrated with the use of instruments such as the wave pump (transport mechanism) or with our current effort to utilize a system of larger ‘bags’ called mesocosms (larger volume subset ) to induce a phytoplankton response. Historically, the mesocosm is akin to the use of lakes or ponds to test the growth response (negative or positive) of an ecosystem when artificially exposed to a variety of chemical substances. The mesocosm does enclose a larger mass of water but it is different from a pond or lake, in that the ratio of the vertical depth (benthic) to the horizontal affords the user unique opportunities to simulate depth or measure stratified characteristics of plankton communities. In this particular cruise experiment, IFM‐GEOMAR and C‐MORE are partnering together to utilize three mesocosms in the open ocean to study the biogeochemical effects to Deep Sea Water (DSW) nutrient additions. This exercise has both engineering and scientific components. The first part is to test the feasibility of deploying and successfully maintaining large scale mesocosms in the open ocean. This mesocosm design has been successfully used in the Arctic region: Ny‐Alosund | Svalbard, so our goal is to extend its usage into more potential hostile conditions. The second part is to measure the surface response of the phytoplankton when deep water macro and micro nutrients are added in.

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Introduction

Post Cruise Summary

Cruise Log

Bridge Log

Cast Sheets