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Team 6: Source and transfer of organic matter in aquatic ecosystems
Contract duration: 
1 Apr 2019 to 31 Aug 2019
MNHN Station de Concarneau
crédits FEAMP
Research topics: 


PhD from 01/10/2014 to 30/08/2019

Title: Impact of shrimp farming on food webs of the Can Gio Mangrove (South Vietnam): tracing using molecular tools and effects on carbon fluxes.

Mangroves are highly valuable ecosystems providing coastal protection, locally available food, biofiltration of organic compounds and carbon storage, among other ecosystem services. The Can Gio mangrove has been totally replanted from 1975, after its complete destruction during Vietnam War. It extends over an area of 70 000 ha, of which 40 000 ha are covered with forests (20% of the total area of mangroves in Vietnam) and 30 000 ha are dedicated to shrimp farming. The core zone, representing 5 000 ha, has been classified as biosphere reserve by UNESCO in 2000. However, the mangrove is fueled by the Nhà Bè estuary, which is draining the biggest city of the country, Ho Chi Minh (8 million inhabitants), and receiving effluents from the intense shrimp farming activity.

The objective of my PhD is to understand the origin and fate of organic matter in trophic webs of Can Gio mangrove. Two sampling campaigns were realized, one in January-February 2015 and the other in September-October 2015. Four sites were monitored during 24 h periods to obtain series of estuary’s data along a continuous salinity gradient. In addition to classical physico-chemical parameters, such as pH, salinity, etc., infra red gas analyzers were employed to measure CO2, and water was sampled every two hour, allowing the recollection of 1600 GF/F filters and 700 water samples. These samples will be processed in part in New Caledonia, in Vietnam, in the United States and in France. They will be used to quantify all forms of carbon in the estuary, C & N isotopic ratios of particulate organic matter, fatty acid composition of particulate organic matter and potential prokaryotic activity. Moreover, organisms were picked along the banks to evaluate transfers in trophic webs.

My PhD contract goes along with a teaching mission, divided equally between statistical courses (Master degree level) and workshops on faunal diversity in ponds (first year of secondary school).

More broadly, my research theme aims to understand trophic relationships in food webs and use this knowledge to develop sustainable aquaculture practices, such as Aquaponics or Integrated Multi-Trophic Aquaculture (IMTA).

Works related to my PhD:

Oral communication:

David F., Taillardat P., Marchand C., Molnar N. and Meziane T. Mangrove ecosystems and shrimp farming interactions along tropical coastlines; a physical and chemical assessment, Triennal Aquaculture 2016, 22-26 February 2016.

Poster presentation:

David F., Taillardat P., Marchand C., Molnar N. and Meziane T. How is shrimp farming impacting mangrove ecosystems in the Indo-Pacific? Triennal Aquaculture 2016, 22-26 February 2016. Available here.

Video communication:

David F., Signore M. and Meziane T., 2015. Extraction des acides gras d'échantillons organiques. Available here.

Previous works:


David F. and Boonsoong B., 2014. Colonisation of leaf litter by lotic macroinvertebrates in a headwater stream of the Phachi River (western Thailand). Fundamental and Applied Limnology/Archiv für Hydrobiologie 184, 109–124. Available here.

Gilles S., Ismiño R., Sánchez H., David F., Núñez J., Dugué R., Darias M.J. and Römer U., 2014. An integrated closed system for fish-plankton aquaculture in Amazonian fresh water. Animal 8, 1319–1328. Available here.