Nadine Lanteri

Gas Seepage along the Edge of the Aquitaine Shelf (France): Origin and Local Fluxes

During the scientific expedition GAZCOGNE2 at the Bay of Biscay nine gas seeps were sampled for the first time and their flux was measured using an in situ pressure-preservation sampler (PEGAZ, ©IFREMER). Overall, three sites were investigated to determine the nature and the origin of the gases bubbling at the seafloor and forming acoustic plumes into the water column, as this was the question raised from the first geologic study of the area. This has guided our study and accordingly corresponds to the main purpose of the present article. Thus, the molecular and isotopic (δD and δ13C) analyses revealed that the gas seeps were primarily composed of methane. Both methane and ethane are of microbial origin, and the former has been generated by microbial reduction of carbon dioxide. Heavier hydrocarbons accounted for less than 0.06% mol of the total amount. Despite the microbial origin of methane, the samples exhibit subtle differences with respect to the values, which varied between −72.7 and −66.1 . It has been suggested that such a discrepancy was predominantly governed by the occurrence of anaerobic methane oxidation. The PEGAZ sampler also enabled us to estimate the local gas fluxes from the sampled streams. The resulting values are extremely heterogeneous between seeps, ranging from 35 to 368 mLn·min−1. Assuming a steady discharge, the mean calculated methane emission for the nine seeps is of 38 kmol·yr−1. Considering the extent of the seep area, this very local estimate suggests that the Aquitaine Shelf is a very appropriate place to study methane discharge and its fate on continental shelves.

Open-Sea Observatories: A New Technology to Bring the Pulse of the Sea to Human Awareness

Historically, observation in Marine Science was mainly based on in situ measurements made mainly over ship surveys and shore measurements. Unfortunately, ship surveys can only be episodic, and are constrained by weather and by the constant rise of ship-time cost. As the data provided by non-communicating moorings are stored in the measurement system, a ship intervention is needed to recover both the mooring and the data after several acquisition months. Further to the rather successful mediumand short-term deployment of these traditional devices, scientists have expected the development of long-term observations and permanent marine system-monitoring tools so as to gain more insight into the observed processes. By providing additional information, satellite technology can partly solve this gap between the reality and expectations. However, even though satellite images provide information over a large time frame (from minutes to years) and a wide range of spatial resolutions (from metres to thousands of kilometres), they only cover the upper layer of the sea. An Open-Sea Observatory is a complementary tool that allows one to make, in the water column and on the seafloor, long-term measurements of many environmental parameters and to acquire them in real-time, or near real-time. In addition to this real-time data transmission, these systems permit remote intervention by humans when needed, and thus can be considered as 2-way communicating devices. Because of these two characteristics, observatories are innovative systems that bring internet to the ocean and make the ocean reality visible to the human eye. According to our definition of an Open-Sea observatory, other very useful observation tools such as gliders, floats, repeated profiler transects, etc. will not be considered in this chapter to only focus on such ocean observatories. Observatory initiatives have been spreading worldwide since the 1990s. In Europe, several initiatives started twenty years ago so as to upgrade free-fall systems from the sea surface (the so-called “landers”) to make them 2-way communicating and to develop bottom

The EMSO-ERIC Pan-European Consortium: data benefits and lessons learned as the legal entity forms

The European Multidisciplinary Seafloor and water-column Observatory (EMSO) European Research Infrastructure Consortium (ERIC) provides power, communications, sensors, and data infrastructure for continuous, high-resolution, (near-)real-time, interactive ocean observations across a multidisciplinary and interdisciplinary range of research areas including biology, geology, chemistry, physics, engineering, and computer science, from polar to subtropical environments, through the water column down to the abyss. Eleven deep-sea and four shallow nodes span from the Arctic through the Atlantic and Mediterranean, to the Black Sea. Coordination among the consortium nodes is being strengthened through the EMSOdev project (H2020), which will produce the EMSO Generic Instrument Module (EGIM). Early installations are now being upgraded, for example, at the Ligurian, Ionian, Azores, and Porcupine Abyssal Plain (PAP) nodes. Significant findings have been flowing in over the years; for example, high-frequency surface and subsurface water-column measurements of the PAP node show an increase in seawater pCO2 (from 339 μatm in 2003 to 353 μatm in 2011) with little variability in the mean air-sea CO2 flux. In the Central Eastern Atlantic, the Oceanic Platform of the Canary Islands open-ocean canary node (aka ESTOC station) has a long-standing time series on water column physical, biogeochemical, and acidification processes that have contributed to the assessment efforts of the Intergovernmental Panel on Climate Change (IPCC). EMSO not only brings together countries and disciplines but also allows the pooling of resources and coordination to assemble harmonized data into a comprehensive regional ocean picture, which will then be made available to researchers and stakeholders worldwide on an open and interoperable access basis.

The EGIM, a generic instrumental module to equip EMSO observatories

The EGIM, EMSO Generic Instrumental Module, developed within the frame of the European project “EmsoDev”, is designed to consistently and continuously measure parameters of interest for the science areas covered by the European Research Infrastructure Consortium EMSO, “European Multidisciplinary Seafloor and water column Observatory”. The EGIM aims to set up a number of ocean locations where the same set of core variables, including temperature, conductivity, pressure, dissolved O2, turbidity, ocean currents, and passive acoustics, are measured homogeneously: using identical hardware, the same sensor references, the same qualification methods, the same calibration methods, the same data format and access, and the same maintenance procedures. The EGIM provides all the services required to ensure the best measurement quality and long-term reliability in line with the Best Practices Handbook by FIXO3 and ESONET-EMSO Label, these services being sensor power distribution, time stamping, data storage and backup, protection against the environment and against fouling and bi-directional communication services… The EGIM is flexible and matches all EMSO site and discipline specific requirements. Operating modes, power requirements, mechanical design, embedded software enable the EGIM to adapt to the various EMSO node configurations: mooring line, sea bed station, cabled or non-cabled and surface buoy. Its compact and its modularity covers an array of deployment scenarios including being able to accommodate new instruments. This will be a key point to the modularity, inter-operability and capacity of the future evolution of the system. Having the EGIM as the sole reference for all nodes is a crucial step towards standardization, increasing global reliability and reducing costs across EMSO.

Seamless integration of EMSO Generic Instrument Module into the internet using sensor web components based on OGC SWE framework

The EMSODEV [1] (European Multidisciplinary Seafloor and waterDcolumn Observatory DEVelopment) is a UE project whose general objective is to set up the full implementation and operation of the EMSO distributed Research Infrastructure (RI), through the development, testing and deployment of an EMSO Generic Instrument Module (EGIM). The scientific drivers for developing and deploying the EGIM across a set of observatories in European Seas are manifold, spanning requirements to collect observations for understanding climate change, marine ecosystems, and geo-hazard early warning research. The EGIM (EMSO Generic Instrument Module) is designed to consistently and continuously measure parameters of interest for most major science areas covered by EMSO. This research infrastructure provides accurate records on marine environmental changes from distributed regional nodes around Europe. EGIM is able to operate on any EMSO node, mooring line, sea bed station, cabled or non-cabled and surface buoy. In fact, a central function of EGIM within the EMSO infrastructure is to have a number of ocean locations where the same set of core variables are measured homogeneously: using the same hardware, same sensor references, same qualification methods, same calibration methods, same data format and access, same maintenance procedures. our contribution to the implementation of the EGIM data acquisition system module focusses on the development of a generic software for sensor web enablement. Through this generic software, the EGIM status data is directly inserted into a centralised SOS (Sensor Observation Service) server and into a laboratory monitor system (Zabbix LabMonitor) for recording events and alarms.