cpwf v3: ecological externalities
Upload: international-water-management-institute-iwmi-cgiar-water-land-and-ecosystems-program
Post on 16-May-2015
315 views
TRANSCRIPT
CPWF-V3Ecological externalities
Ph. Cecchi (IRD G-eau)S. Sanogo (Univ. Bobo)
(logos to be added)
Andes • Ganges • Limpopo • Mekong • Nile • Volta
1. Lakes monitoring (water level)
Level and temperature loggers installation (June 2011)
250
300
350
400
450
500
550
15/6 15/7 15/8 15/9 15/10 15/11 15/12 15/1 15/2 15/3
Relative Variations of Water Level (cm)
4.2 Mm3
1.2 Mm3 ≈ 30%
Usable?? By whom=> Conflicts?
? Hydro. => Filing up?
Andes • Ganges • Limpopo • Mekong • Nile • Volta
1. Lakes monitoring (temperatures)
0
5
10
15
20
25
15/6 15/7 15/8 15/9 15/10 15/11 15/12 15/1 15/2 15/3
Daily Variations of Temperatures (°C)
dT (Bottom of the Lake)
dT (air)
Mean depth = 2.1 mVertical Mixing sensitivity
Mechanical Buffer?
Andes • Ganges • Limpopo • Mekong • Nile • Volta
2. Ceratophyllum submersumProliferation since a couple of years 1/ Strong LOCAL preoccupation:
- Infrastructures- Fishery
2/ METABOLISM consequences- Quality & productivity
3/ SCIENTIFIC priority- causes & impacts
From an ecosystem perspective, the simultaneous dominance of cyanobacteria in the phytoplankton pool (> 60%) and the invasion of water masses
by huge amounts of macrophyte do point out without ambiguity the advanced eutrophication status of the Boura reservoir.
Andes • Ganges • Limpopo • Mekong • Nile • Volta
MACROPHYTES(clear)
PHYTOPLANKTON(turbid)
BEFORENOW
WHEN?
WHY?
Both states are RESILIENT
Andes • Ganges • Limpopo • Mekong • Nile • Volta
Algae Turbidity
SedimentResuspension
Nutrients
Cerato
? Allelopathy
? Pesticides
? Hydrodynamics
? Agri. practices
? Origins
Fish? Structure
Diagnose: realized by V3 projectRemediation: support to local communities
Andes • Ganges • Limpopo • Mekong • Nile • Volta
3. Allelopathy?
40%
50%
60%
70%
80%
90%
100%
REF PICK1 PICK2 PICK3 PICK4 PICK5
Y (%)A
D
C
BC
AB
AF= 41.643; P< 0.001
Preliminar experiments have confirmed the allelopathic potential ofCeratophyllum submersum.
Andes • Ganges • Limpopo • Mekong • Nile • Volta
4. Pesticides?
0%
10%
20%
30%
40%
50%
60%
70%
Agri Ref
Dytiscidae
Hydrophylidae
Macro-invertebrates communities exhibited contrasted patterns in agriculture-impacted versus reference stations
Andes • Ganges • Limpopo • Mekong • Nile • Volta
4. Pesticides?
Tee shirt distributed by an agrochemical company in Ghana(Binaba, April 2011).
Commercial formulation (paraquat-based) found in fields (Boura, March 2012).
Andes • Ganges • Limpopo • Mekong • Nile • Volta
5. Perspectives: towards chemical ecology
1/ What could be the cumulative effects (antagonism / synergy / others) of both allelopathic metabolites and phytosanitary by-products on the aquatic productivity and diversity?
2/ What could be the effects on the growth performances of irrigated cultures?
3/ Implementation of dedicated experiments using pesticides collected by passive samplers (in situ), pure molecules (paraquat) and allelopathic metabolites
4/ Impacts on aquatic food web structure and on selected irrigated crops.
Output: better understanding of the nexus linking ‘Agricultural Intensification’ & ‘Ecosystem Resilience’…