Benthic compartment and process
Lead: CNRS (Antoine Grémare)
During the FP7 JERICO, a strong focus has been put on the development of new semi-automatic techniques allowing for the assessment of the structuration of benthic communities. This in particular led to the development of a set of software designed to facilitate and homogenize (i.e., between users) the processing of images acquired using different vectors including sediment profile images (see WP6 and 7) and mobile carriers. Within JERICO-NEXT, we will go deeper in this approach by: (1) developing a new mobile carrier for image acquisition, and (2) achieving new technological developments regarding the monitoring of a key benthic biogeochemical process: organic matter remineralization.
Subtask: 3.6.1 Integrated multi-sensors video array towed fish (led by Ifremer): Within JERICO-NEXT we will modify an existing towed underwater video sledge (“Pagure” imagery tool) to a flying configuration that will not contact the sea floor to allow use in hard bottom and mixed substrates, which cover a large part of European coastal areas, as well as in marine protected zones where disturbance of the sea floor is unacceptable. The new non-destructive configuration will be used to investigate and map epifaunal benthic biodiversity as well as impacts of benthic invasive (or proliferating) species. New sensors will measure important environmental parameters to help to better characterize the ecological status of benthic habitats. Sensors will include an oxygen probe, laser lines to assess surface microtopography (including features created by burrowing animals) and a small bottom sediment profiler. This development will allow more comprehensive insights into the integrity of benthic habitats and will be also relevant to investigation of areas adversely affected by human activities (bottom-trawling, sand-mining, marine renewable energy development). This tool will be easily deployable on small (~25 m) coastal vessels as well as large research vessels.
Subtask: 3.6.2 Organic Matter mineralisation (led by CNRS): Organic matter mineralization is highly relevant for several MSFD descriptors including biodiversity, eutrophication and to a lesser extent sea floor integrity. Organic matter mineralization at the sediment-water interface can be assessed using a large variety of methodological approaches including incubation, vertical profiling of oxygen concentrations within the sediment column, and eddy covariance techniques, which couples high frequency measurements of turbulence and oxygen concentrations) allowing for high frequency and spatially integrated measurements of oxygen fluxes. During JERICO-NEXT we will focus on these last two techniques since they are: (1) complementary in terms of the range of spatial scale assessed, and (2) both already automated and thus present the best potential for deployments during long term observation periods We will adapt and test an existing sediment oxygen microprofiler during long observation periods, and an eddy covariance system to allow for repeated acquisition sequences.
Deliverable 3.10: Report after developments dedicated to monitor and study benthic comportment and processes (M24). It will describe: the technical adaptation of the existing “Pagure” towed underwater video system into a “flying” video system equipped with sensors of environmental parameters and on deployment tests; and the adaptation provided to both the sediment oxygen microprofiler and the eddy covariance system and on the results of the deployment trials achieve.