Jerome Blandin

TEMPO: a new ecological module for studying deep-sea community dynamics at hydrothermal vents

The major goal of this project, elaborated in the frame of the STREP Exocet/D European project, was to design a first autonomous long-term imaging module equipped with a deep-sea video camera, adequate lightning and sufficient energy storage while taking advantage of most recent progress in imaging and photonics. The new ecological module TEMPO was tested and deployed during the Momareto cruise held from August 6 to September 6, 2006 on the new French oceanographic vessel Pourquoi pas?, with the ROV Victor 6000. The scientific objectives of the Momareto cruise were to study the spatial and temporal dynamics of hydrothermal communities colonizing the MoMAR zone, located on the Azores Triple Junction.

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

Scientific specifications, common and complementary developments for deep sea and coastal fixed point multidisciplinary cabled observatories

The developments of subsea observatories has been addressed by several national and European projects involving Ifremer engineering teams during the last decade. The motivation of scientific research disciplines has been growing during the same period. The coordination of ESONET Network of Excellence has been a unique occasion to analyse the best practices world wide and propose standards and recommendations. The merger of existing observatories and construction of new deep sea observatories in Europe is now organized at European level through EMSO (European Multidisciplinary Seafloor Observatory). Its preparatory phase is now building a multi-site large research infrastructure. The French participation is planned through the EMSO-France initiative. The need to monitor the sea environment is also acute in the coastal zone as Marine Protective Areas, indicators of marine biodiversity and ecological quality are requested by the marine strategy directives (such as European Marine Strategy Framework Directive). The cost effectiveness of the long term observatories will gain from a choice of common technologies and operating methods for coastal observatories and deep sea networks. Innovative solutions are proposed in the fields of: biofouling protection, sensor web enable interface, sensor registry, data management, material choice, energy requirements, junction box designs,… A review of these solutions is presented in the paper. Coastal cabled observatories such as MeDON are used as test benches for several of these new developments. Even in the cases when depth will induce different technologies, the deep sea cabled and shallow water cabled observatories may be designed in such a way that operating methods will be similar (components, subsea intervention methods, remote maintenance procedures, network management practices, sensor calibration procedures,…). Ifremer engineering teams are using the ongoing projects to enhance reliability in shallow as well as deep water cabled observatories.

Long term in situ survey of total dissolved iron concentrations on the MoMAR observatory

Study of the temporal dynamics of faunal assemblages and their habitat at the Lucky strike vent was performed using the TEMPO ecological module on the MoMAR (Monitoring of the Mid-Atlantic Ridge) deep sea observatory. An in situ analyzer (CHEMINI) was implemented onto this structure in order to determine total dissolved iron concentrations associated with an optode and a temperature probe. Hence, we present here the long term in situ analysis of total dissolved iron (6 months, 2013-2014) at the Eiffel Tower edifice. The daily analyzed in situ standard (25μmol.L-1) showed an excellent reproducibility (1.07%, n=522), illustrating the good analytical performances of the CHEMINI, validating the iron concentrations measured by the instrument. CHEMINI was reliable, robust over time for in situ analysis. The averaged total dissolved iron concentrations for the 6 months period remain low ([DFe] = 7.12 ± 2.11 μmol L-1, n = 519), but display some noticeable variations related to the temperature. Indeed, iron and temperature correlated significantly, and frequency spectra indicated a maximal contribution of frequencies around 4-5 days for both variables.