The EUR-OCEANS workshop “Macro nutrient dynamics in marine ecosystems” will take place in Heraklion, Greece, at the Hellenic Centre for Marine Research during the period from September 30th to October 4th 2007.

 

Marine ecosystems are subject to permanent or periodic: i) P or N limitation or, ii) colimitation of the latter. Although we have relatively good access to “snap-shot data” (descriptive data), less research has been devoted to patterns and pathways behind these limitations. Previous studies have mainly documented the behaviour of total communities vs. limitation by a limiting (most often single) element.

 

Examples: Silicon is a control factor of community dominance by diatoms with ultimate impact on P/N ratios as well as on the community changes. Trace-elements supply is a key factor triggering the size structure of pelagic primary producers, thereby altering P/N stoichiometry of biogenic matter.

 

In general, it will be highly timely to include the study at species level with the idea to

instantaneously consider the “multi-elemental” (nutrients, time scales, etc.) dynamics

We can assume as one of the above pathways, factors modifying the P/N Redfield ratio:

 

• Irradiance-vertical mixing, stratification, etc.

• Changes in current circulations

• Strong blooms of a given category of either auto or heterotrophic organisms

• Land driven discharges with already modified P/N/Si ratio

• Atmospheric inputs (dust, organics, etc.)

• Limitation in micronutrients (periodic or permanent)

Some of these pathways can be affected by human activities under multiple aspects

(agricultures, urban pollution, “regional (?)” climate changes, etc.).

 

We need mechanistic approaches to understand these pathways. In other words, one should target the understanding of major ecosystem processes rather than focussing on observational research alone. The goal could be to achieve formulation and parameterization of processes at the individual or key species level. Important processes include co-limitation with the need here to produce new hypothesis, formulation, concepts, etc. In that sense cell activity markers including molecular approaches should likely not be underestimated or omitted (specific activity probes, gene expression for key enzyme activities of metabolic functions such as nitrate reduction, nitrogen fixation, alkaline phosphatase, 5’-nucleotidase, ...).

 

The Biogeochemistry WP of EUR-OCEANS is one of the few opportunities to attempt the creation of such a working group through subject-oriented meetings and workshops with a goal to reach functional European research teams within futures RTD programs.

 

We invite you to participate. Please do note that there is a maximum number of participants that can be hosted. We might, therefore, have to make a selection.

 

 

You are kindly requested to use the following contacts

 

    - For title and the abstract of your talk to be sent by the first September dead-line : Drs Bernard Quéguiner (bernard.queguiner@com.univmed.fr) and Fereidoun Rassoulzadegan (rassoul@obs-vlfr.fr)

    - For the local information and logistic: Dr Paraskevi Pitta (vpitta@her.hcmr.gr)

-         For general administrative, EUR-OCEANS information and rules, etc: Drs Frede Thingstad (Frede.Thingstad@bio.uib.no) and Yngve Børsheim (yngve.borsheim@imr.no)”

 

Deadline for application: 30 April 2007

Dates: Sunday 30 September until Thursday 4 October, 2007