2014 SCOR InterRidge Working Group Report

N. Le Bris 31.05.2014

The  Working Group has organized its third meeting in Vienna, Austria, in the context of the European Geosciences Union General Assembly 2014. The WG meeting was held  on April 28th, with the primary aim of discussing the review papers that are proposed as deliverables in the WG terms of references.

The primary aim of the meeting was to discuss the progress of review papers to be finalized by the end of this year. S. Sanders, L. Legendre and C.R. German have lead a first review paper focussing on hydrothermal plume interaction with the oceanic water masses. A review outline set up and was discussed for the second paper. In addition to synthesizing the current knowledge, the aim of this review is to identify gaps, which will justify the development of a large scale in situ interdisciplinary experiments and the necessary adaptation of instruments and methods to the particularly extreme conditions of these deep-sea environments in the upcoming years.

The tighly constrained agendas of most WG members who are involved intensifying at-sea programmes (IODP, GEOTRACE, ..) impede the organization of a workshop as we first planned. The EGU conference offered an alternative to present the different research activities lying behind the theme of ‘Hydrothermal energy transfer and its relation to ocean carbon cycling’. In addition to the WG meeting, on May 2^nd, an oral communication and poster session were hold in the Biogeoscience programme of EGU (session abstract and presentation list below). The session also included flash poster presentations on April 30.

All these events constituted an opportunity to gather 8 of the WG members together with 6 young scientists (PhD student or post-docs) covering the various disciplinary aspect and topics of the WG theme. It was given the young scientist the opportunity to be  included in the discussion and in the preparation of the review. Their works, in collaboration with different group members, are indeed of high relevant to the review process.

Next stages involve the resubmission of the paper on the biogeochemical impacts of hydrothermal plumes, and the drafting of the six sessions of the complete review, which is considered due by September.

Participants to the meeting

Working group members : Nadine Le Bris, Sylvia Sander, Louis Legendre, Katrina Edwards, Sylvia Sander, Xiqiu Han, Loka Bharathi P.A., Chris R. German

Young scientists : Anindita Das (coll. L. Bharathi) , Gustavo Ramírez (PhD student, K. E. Edwards), Charles Vidoudez (Post-doc P. Girguis and coll. W. Bach, N. Dubillier), Mustafa Yücel (coll. G.W. Luther, and coll. N. Le Bris), Sarah Bennett (coll. C.R. German), Solveig I. Bühring (coll. S. Sievert).

EGU session BG7.2 Convener: Nadine Le Bris, Co-Convener: Chris German

Hydrothermal energy transfer and its relation to ocean carbon cycling: from mechanisms and rates to services for marine ecosystems

Hydrothermal systems in the deep ocean have been studied from the past 37 years, but their impact on the ocean biogeochemistry and related ecological processes is far from being understood. Vent ecosystems were long described as largely independent from the photosynthesis-driven biosphere, a paradigm which no longer stands. Today we have a slightly clearer picture of the role energy transfer from hydrothermal circulation could play on ecosystems across a range of depths and on subseafloor carbon sequestration. At a time the exploration and exploitation of deep-sea mineral resources is rapidly developing, with potential impacts to habitats and biodiversity, there is a urgent need to consider the potential ‘services’ that is provided by these systems to the ocean.

The aim of this session is to synthesize the most advanced knowledge on:

1) carbon-fixation pathways in the different compartments influenced by hydrothermal activity, the metabolic diversity sustaining them and their dependence on oceanic processes,

2) biotic and abiotic drivers of productivity of related seafloor and subseafloor ecosystems, their natural dynamics and sensitivity to disturbance,

3) hydrothermally-derived fluxes of micronutrients and exported DOC and their potential influence on ocean biogeochemistry at larger scale.

4) integration of these processes into conceptual models of energy transfer and carbon cycling.

Our objective is also to enlarge the discussion outside the field of vent research with a broader scientific community and determine the opportunities to bridge scientific efforts focussing on these environments with larger marine science programmes in view of a future assessment the potential contribution that they may make to the ocean ecosystems and carbon cycle at different scales. This session is organized as part of the InterRidge and SCOR WG135 working group activities.

Oral presentations