Effect of warming and terrestrial Dissolved Organic Matter on the structure and functioning of coastal Mediterranean plankton communities
There is no doubt that climate warming will impact coastal water, in particular in shallow ones, in the near future. However, warming will not coming alone and it will interact with other environmental changes. Flashflood events are a common rule of the Mediterranean climate and a recrudescence of these events is envisaged. During these events the resulting freshwater crossing the watershed can suddenly brings several organic and inorganic elements of terrestrial origin to the coastal waters. One of these elements is the terrestrial Dissolved Organic Matter (tDOM). A suddenly huge amount of organic matter will most probably increase the heterotrophic prokaryotes activities. At the same time warming will impact the structure and functioning of the plankton food web (Vidussi et al. 2011). Therefore, in a context of climate warming, the tDOM and temperature increases in the near future can affect the planktonic communities. To study the effects of these perturbations on the structure and functioning of coastal planktonic Mediterranean communities, separate and simultaneous increase of water temperature simulating global warming and tDOM will be investigated using the pelagic in situ mesocosms of MEDIMEER. The in situ mesocosms will be immerged in the natural water column and therefore its water temperatures follow the natural water temperature variations during the day/night periods as well as during several weeks of the experimentations. The water column of several mesocosms will be increased and maintained at +3°C relative to other in situ mesocosms with natural water temperature (Vidussi et al. 2011). Four treatments will be applied each in triplicate mesocosms:
- Natural water temperature,
- Increased water temperature (+3°C),
- Natural water temperature and added tDOM, and
- Increased water temperature (+3°C) and added tDOM.
This mesocosm experiment will be realized during 3 weeks in April and May 2019 depending on meteorological conditions at CNRS-MARBEC MEDIMEER facility in 2019. A project entitled RESTORE for studying these effects was submitted to the French National Research Agency (ANR) and the results about its funding will be known in August. If this project is funded by ANR, several parameters will be covered by the RESTORE consortium. However, as a Transnational Access (TA), international scientists and trainees are very welcome to participate to this experiment for specific topics which will be announced later. This experiment will be also an occasion to test new methods to study the plankton food web components or functioning like use of underwater camera or cytometry to study large and small plankton, or other underwater instruments like in situ Fast repetition fluorometer to study photosynthesis, etc. Master and PhD students are also very welcome for training and they will be supervised by the local team. International scientists and students are encouraged to contact the local scientists for propositions (Behzad.Mostajir@umontpellier.fr). In this experiment, about 10 scientists including students can participate.
If this project is not funded by the ANR, a part of this project or another project will be suggested for TA.
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Vidussi F, Mostajir B et al. (2011). Effects of experimental warming and increased ultraviolet B radiation on the Mediterranean plankton food web. Limnology & Oceanography 56 (1): 206-218
WARM PLANK – Effects of warming on the Mediterranean plankton food web functioning. Project lead: Behzad Mostajir. 03-24/04 2018 & 02-23/10 2018
Effect of increasing water temperature simulating global warming on the Mediterranean plankton food web functioning will be investigated using the pelagic in situ mesocosms of MEDIMEER in spring and fall 2018. In each of spring and fall mesocosm experiment approved Transnational Access users can participate. The applicants are encouraged to participate to both experiments; however this is not an obligation. A total of 252 person days can be allocated to external users involved AQUACOSM Transnational Access provision in 2018. We offer access to 10-12 persons for 20-25 days in 2018. The access cost offered by MEDIMEER is based on real cost calculation, which includes all needed preparatory work (before and at site), as well as specific training needed at the sites to complete the specific projects.
The spring experiment will be realized from April 03 2018 during 3 weeks depending on meteorological conditions. This experiment is part of the PHOTOPHYTO project funded by the French National Research Agency (ANR). It focuses on the effects of global warming on the timing of marine phytoplankton blooms taking into account the different interactions between biotic and abiotic components, specially the match/mismatch between predator/prey. The in situ mesocosms are immerged in the natural water column and therefore its water temperatures follow the natural water temperature variations during the day/night periods as well as during the several weeks of the experimentations. The water column of several mesocosms will be increased and maintained at +3°C relative to other in situ mesocosms which act as CONTROLS mesocosms (Vidussi et al. 2011).
In the spring experiment, the large majority of physicochemical parameters and biological ones such as abundances, biomasses of organisms and related processes (primary production, respiration, growth, grazing, etc.) will be investigated by the scientists involved in the PHOTOPHYTO consortium. However, as a TA, international scientists are welcome to participate to this experiment for specific topics such as viral ecology, parasitism, molecular diversity, metabolomics, biochemical composition of plankton, taxonomy of phytoplankton and zooplankton, prey/predator interactions (note that the dilution experiments are already scheduled). Master and PhD students are also welcome for training and they will be supervised by the local team. In addition, by collaborating with the local team, this experiment will be an occasion to test new ecological hypothesis regarding the warming effect on the marine plankton as well as new methods to study the plankton food web components or functioning like use of underwater camera to study larger plankton, or other underwater instruments like in situ Fast repetition fluorometer to study photosynthesis, etc. International scientists are encouraged to contact the local scientists for propositions (Please login or register to view contact information.).
As there are also some phytoplankton blooms in fall in the Mediterranean coastal water, the fall experiment with more or less a similar design and protocols will permit to study the effect of increased warming on the functioning of plankton food web in the fall after the transition of the hot Mediterranean summer. The fall experiment will be carried out from October 02 2018 during 3 weeks depending on meteorological conditions.
Vidussi F, Mostajir B et al. (2011). Effects of experimental warming and increased ultraviolet B radiation on the Mediterranean plankton food web. Limnology & Oceanography 56 (1): 206-218
Pelagic, marine, outdoor, in-situ
1. Permanent floating structure: up to 12 pelagic mesocosms (1.2 m diameter, 2 m depth, ~2 m3 volume each). Fig. 1 & 2
2. Permanent floating structure: 3. Indoor structure:
3. Mobile: LAMP is composed of 9 individual structures that can be deployed individually or bonded according to experimental design. Fig. 3
CO2, pH, nutrients, plankton composition, temperature, light, salinity, turbulence, conductivity, chlorophyll a fluorescence and dissolved oxygen concentration. Some of The data are stored and transmit in real time
Plankton food web structure and functioning and their responses to global and local stressors.
Interactions between planktonic organisms and changes in structure and function of planktonic food web.
Effects of warming, increase of ultraviolet-B radiation and pH on planktonic food web.
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Sète, France
MEDIMEER is a unique platform on the French Mediterranean coast designed to run in-situ mesocosm experiments in coastal waters (Fig. 6.8.1). The facility with up to 12 pelagic mesocosms (1.2 m diameter, 2 m depth, ~2 m3 volume each) is moored in the Lagoon of Thau 20 km southwest of Montpellier, hosted by the Marine Station of Sète, which belongs to the University of Montpellier. The mesocosms are attached to pontoons, maintained by a floating structure made of stainless steel and moored in the lagoon to provide natural water-temperature and light conditions. Three mesocosms can be instrumented, enabling the acquisition of high-frequency data during experiments. Moreover, instruments for continuous measurements of temperature and solar irradiance are installed on the same pontoon.
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Fig. 6.8.1. MEDIMEER pontoon and mesocosms moored in situ. Photos: B. Mostajir
Several laboratories of the University of Montpellier hosted at the Marine Station of Sète immediately adjacent to the mesocosm infrastructure are dedicated to participating in MEDIMEER experiments. They provide access to 2 wet laboratories (total area of 35 m ), 2 microbiological laboratories (total area of 35 m2), a chemical laboratory (15 m2), 4 other laboratories (total of 65 m2 for sample processing), a workshop (50 m ) and office space (20 m ).
Available equipment and instruments include a spectrofluorimeter, a spectrophotometer with an integrating sphere, an oxygen titrator, an autoanalser for dissolved nutrients, a flow cytometer (FacsCalibur), an epifluorescence microscope, dissecting microsopes, and various benchtop instruments (peristaltic pumps, vacuum pumps, filtration sets, liquid nitrogen container, balances, incubators, drying ovens, cooled centrifuges, hoods, etc.)
Analytical platform, isotope laboratory, cold rooms, physical instrumentation (Conductivity, Temp, O2, pH), optical (fluorescence), biological (phytoplankton measures), biophysics (fluorimeter, spectrophotometer)
Services currently offered by the infrastructure: Users will get full access to the mesocosms, laboratories and equipment available in the laboratories participating in MEDIMER. The large water volume in the mesocosms permits intense and repeated sampling for several weeks and multiple users. High-frequency data from automatic sensor measurements made before and during experiments can be provided by collaborating with local teams. To date, a number of mesocosm experiments realized through nationally funded projects and Transnational Access provision during the MESOAQUA FP7 project, have already benefitted from MEDIMEER. Topics have ranged from bacteria to zooplankton responses to various aspects global environmental changes
Support offered under AQUACOSM: All users will be offered technical, logistic and scientific support before and during the experiments. This includes:
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Access to the MEDIMER mesocosms and associated materials for experimentation
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Access to temperature and solar irradiance data recorded by the weather station at the site
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Access to a range of laboratories in the Marine Station of Sète (see above)
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Standard lab equipment such as fridges, freezers, liquid N, bench-top hoods, autoclaves, distilled water
and ultra-pure water
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Technical and logistic support and supervision for using the experimental facility
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Training on specific instruments by MEDIMEER technical staff and collaboration with local staff during sample and data analysis.
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There are also a boat, aquaculture tanks, cold room, and possibility for animal collection by a diver.
Dormitories at the Marine Station of Sète or possibility to rent the hotel rooms or a villa.
