Marine plankton play a crucial role in the functioning of marine ecosystems and global biogeochemical cycles, but also for human populations through a number of ecosystem services. These services include: 1) the production of half of the oxygen we breathe, 2) the energy supply of marine food webs, which in turn sustain many human populations, and 3) the transfer of atmospheric carbon released by human activities to the depths of the ocean in the form of organic matter, and thus 4) the regulation of the climate of planet Earth. The application of high throughput sequencing (or metagenomic) techniques to marine plankton has recently revealed the great diversity of planktonic organisms in the ocean. However, plankton remains very coarsely represented in global biogeochemical models (using only a few "black boxes"), including in the models used by the IPCC to simulate the fate of the Earth system by 2100. This gap affects our ability to accurately predict the response of plankton communities to climate change and thus the ecosystem services provided by marine plankton. As plankton ecosystems face increasing climatic and anthropogenic pressures, there is a critical need to train a new generation of early-stage researchers (ESR) at the crossroads of complementary and yet independent scientific expertises. To meet this need, we wish to submit in January 2019 the PlankServ project in response to the European call MSCA-ITN-ETN-2019. PlankServ will provide a multinational and multidisciplinary European Training Network (ETN) that will draw on the expertise, complementarity and synergy of European research and training centers based in France, Germany, Spain, United Kingdom, and Switzerland. This European training network is also intended to include non-academic partners, such as biotechnology companies specialized in Big Data, insurance companies, NGOs and consulting firms dedicated to the management of marine ecosystems, scientific editors, and institutions for disseminating scientific culture. The ESRs will be trained in genomics, marine ecology, biogeochemistry, climate sciences and numerical modeling, but also in the manipulation of large data sets ('big data'), risk assessment, ecosystem services assessment, management of marine ecosystems, and communication to the general public and the media. These ESRs will develop unique skills that will allow them to advance their careers in various sectors of activity such as consulting, governance, communication, academia or industry. To set up this European network, the main academic partners have already been identified (and have already collaborated in several smaller projects), but we still have to mobilize the non-academic sector, a crucial point for obtaining MSCA-ITN funding, since they must represent at least 40% of the members of the network. The main purpose of the Pre-PlankServ project is to enable the mobilization of these non-academic partners. It will also make it possible to organize two meetings between the various members of the network (in addition to videoconferences planned each 3 months in 2018). The first meeting will focus on updating on the responses we would have obtained from the private partners that we would have contacted, finalizing the structure of the consortium, writing the thesis topics that will be co-supervised within the training network, and planning the training actions for each ESR and for the PlankServ network. The second meeting will finalize the drafting of the PlankServ project no later than 2 to 3 months before the closing of the MSCA-ITN call that is planned for January 2019.