Seminar by Christophe Guinet (CEBC, Chizé) on April 1 at 11:30 am

Sea elephants bio-samplers of oceanographic conditions: measurement of new oceanographic parameters and assessment of intermediate biological levels.

Summary: In recent years, Kerguelen elephant seals have become an essential component of the National Observing System: Bio-Sampling Mammals of the Ocean Environment for the observation of oceanographic conditions in the Indian sector of the Southern Ocean. Temperature, salinity, and fluorescence are now recorded continuously and at high frequency (0.5 Hz) over periods of several months. More recently, our efforts have focused on the evaluation of new environmental parameters. First of all, as part of Dorian Cazau’s post-doctoral fellowship at ENSTA-B, we were able to evaluate wind strength and direction and sea state (wave frequency and amplitude) by combining acoustic, acceleration and magnetometry measurements. In addition, our research activities in recent years have focused on studying biological levels: phytoplankton to elephant seal prey, as well as assessing the distribution and density of intermediate levels (zooplankton and micro-nekton). To this end, new generations of recorders have been developed in partnership with the Sea Mammal Research Unit, namely a high-frequency, low-energy micro-sounder that can detect the presence of planktonic and micro-nectonic biological organisms during sea elephant diving. In parallel, high sensitivity bioluminescence sensors sampling light at very high frequencies. By simultaneously measuring continuous and high frequency oceanographic and biological parameters, elephant seals have become essential bio-samplers for assessing the influence of oceanographic conditions on the fine scale structure of the different biological levels in the Southern Ocean.

Seminar by Miguel A. Tripp-Valdez – March 4th, 11:00

Miguel A. Tripp-Valdez will present his research during a seminar on monday March 4th, at 11:00 in room A215.

Effects of hypoxia and hypercapnia on thermal tolerance: an integrative assessment on the green abalone (Haliotis fulgens)

Miguel did his PhD at CIBNOR (Mexico) on the thermal tolerance and the metabolic and molecular response of green abalone (Haliotis fulgens) to hypoxia and hypercapnia. He is present at LEMAR to discuss about a potential post-doctoral project.

Effects of Omega 3 depletion on marine fish: ecophysiological approach

There is increasing evidence that climate change might critically deplete nutrients in food web of marine fish. In particular, a reduction in the production of Omega 3 (Ω3) in phytoplankton as a result of ocean warming can have negative impact on fish. Ω3 are fatty acids that are essential components of cell membranes. Such depletion in Ω3 in membranes can impair fish performance, however, the underlying mechanisms remain obscure. Mitochondria are likely to be involved in the fish response to Ω3 depletion. Changes in the composition of membrane fatty acid of mitochondria affect their efficiency. Organisms that have less efficient mitochondria are less able to maintain ATP [Adenosine TriPhosphate) production, a feature that is likely to affect the overall animal performance. This PhD work will therefore evaluate how the reduction in dietary Ω3 affect mitochondrial function and in turn the performance of a fish, the mullet (Liza aurata)

Thesis supervisor: José-Luis Zambonino-Infante

Thesis co-supervisor: Karine Salin

Read the terms and conditions and download the application form here:

https://wwz.ifremer.fr/Actualites-et-Agenda/Toutes-les-actualites/Theses-2019

Applications must be submitted before 30 June 2019, but we strongly encourage you to announce your intention to apply as soon as possible, by contacting the persons in charge of the subject.

Mark Ohman’s seminar on February 28th at 2pm

On February 28th at 2pm in amphitheatre A at IUEM, we will welcome Mark Ohman (Scripps Institution of Oceanography, University of California, San Diego) who will present us his work on the following topic:

Dynamics of an Eastern Boundary Current Ecosystem:  The California Current Ecosystem LTER site.

Below is a summary of his presentation.

The California Current Ecosystem Long Term Ecological Research (CCE-LTER) site is an hypothesis-driven, interdisciplinary research program that addresses multi-scale changes in a major Eastern Boundary Current upwelling ecosystem. CCE-LTER benefits from the pre-existing CalCOFI time series, now in its 70th year, which provides important context for distinguishing true secular changes from intrinsic ocean variability. CCE-LTER is a multi-faceted program that integrates Lagrangian-design experimental cruises, diverse observational technologies (both shipboard and autonomous), multiple modeling efforts, human capacity-building, and outreach. Of several possible mechanisms underlying pelagic ecosystem change in this region, the CCE-LTER group is currently focusing on temporal variability of cross-shore fluxes associated with coastal upwelling filaments. Our research targets the planktonic components of the pelagic ecosystem, viewed from both ecological and biogeochemical perspectives.

This presentation will provide a brief overview of CCE-LTER, which is based at the Scripps Institution of Oceanography but includes partners at 6 other institutions, and is supported by the U.S. National Science Foundation. The presentation will also touch on the capabilities of Zooglider, a new autonomous zooplankton-sensing vehicle designed and constructed by the Instrument Development Group at Scripps. It employs in situ shadowgraph imaging and dual-frequency acoustic backscatter to characterize the zooplankton community, and is now being utilized in the context of CCE-LTER.

conference by Griet Neukermans on february 5th, 11::00

Griet Neukermans (LOV Villefranche) will give a conference on february 5th in room A215 at 11:00.

Carbon export from coccolithophore blooms using BGC-Argo floats