Transcript Gehlen_WP11_100608

Kick-off meeting
Nice 10 – 13/06/2008
WP 11
- Biogeochemical Impacts -
Kick-off meeting
Nice 10 – 13/06/2008
 Objectives:
 Determine impacts of ocean acidification on C and other key element cycles as
well as climate relevant gases (CO2, DMS, N2O) from regional to global scales.
 Assess the impact of emission scenarios on simulated ecosystem structure and
function.
 Quantify the changing role of marine sediments as sinks and sources of
macro- and micro-nutrients (P, Fe) under future ocean acidification and climate
change scenarios and investigate the impact of these changes on shelf and open
ocean ecosystems and biogeochemistry.
 Assess the potential of different long-term observation approaches
(radionuclides, alkalinity changes, sediment traps) for detecting impacts due to
ocean acidification.
Kick-off meeting
Nice 10 – 13/06/2008
 Approach:
Use a hierarchy of regional to global biogeochemical-ecosystem models, some
of which include not only the water column but also couple that to an
interactive benthic compartment
Tasks:
1/3
Model Development: to incorporate new process knowledge from WP9 in order
to better evaluate how ocean acidification affects individual processes and
improve 3-D ocean biogeochemical and ecosystem models.
Where we start from:
pH sensitive processes taken into account in large scale models …
BIOLOGICAL PUMPS
AIR
cold
fresh


warm
haline
SOLUBILITY
HIGH
LOW
TWILIGHT
ZONE

PHOTOSYNTHESIS
Nutrient &CO2 uptake
POC flux

SURFACE
OCEAN
ORGANIC C PUMP


SOLUTION PUMP
CaCO3 COUNTER
PUMP
CALCIFICATION
CO2 release
ALK consumption
CaCO3 flux
REMINERALISATION
DEEP OCEAN
SEDIMENT
Nutrient &CO2 release
CaCO3 dissolution
ALK release
BENTHIC REMIN.
BENTHIC DISS.
Nutrient & CO2 release
ALK release
Kick-off meeting
Nice 10 – 13/06/2008
Tasks:
2/3
Model Performance Assessment: to evaluate the capability of models to
reproduce existing and new datasets of dissolved properties (e.g., carbonate
system parameters [WP10], O2, nutrients);
+ Model output will be compared to relevant data, particularly where model
domains overlap (e.g. the North West African upwelling system).
+ New data for the biogeography of calcifying organisms from WP3 will be
exploited.
 Tasks: 3/3
 Model-based assessment of impacts of ocean acidification on key
biogeochemical and ecosystem processes, including sediment biogeochemistry
CO2
N2O
DMS
- ecosystem structure &
productivity
- stoichiometry of C fix
- export production
- CaCO3 production
- air-sea fluxes
- remineralization of organic
- particle aggregation
- ballasting
- CaCO3 dissolution
- rain ratio
- bioavailability of nutrients
(including sediment source)
Kick-off meeting
Nice 10 – 13/06/2008
Deliverables:
Link to monitoring :
 Report on potential methods for detecting the impact of ocean acidification on marine
particle fluxes (rain ratio effect)
Model perfomance assessment :
 Report evaluating the performance of all models and their developments in terms of
their capability to reproduce past and present observations
Impacts of ocean acidification :
 … on the global fluxes of climate relevant gases
… and climate change on the sea floor as a source of macro- and micronutrients to the oceans (P, Fe)
 … on individual biogeochemical processes at the regional, basin & global scales :
report on future uncertainties and thersholds (input to WP13)
Impacts of anthropogenic C emissions (past, present, future) :
… on ocean biogeochemistry and ecosystems
Kick-off meeting
Nice 10 – 13/06/2008
 Participation teams :
(1) shelf seas :
ETH Zürich
Plymouth Marine Laboratory
Universiteit Utrecht
(2) regional scale : Alfred Wegener Institut für Polar- u. Meeresforschung
ETH Zürich
(3) global scale/ : Laboratoire des Sciences et de l’Environnement
and Earth Syst. University of Bergen
Universität Bern
Max-Planck-Institut für Meteorologie
University of Bristol (model of intermediate complexity)
Kick-off meeting
Nice 10 – 13/06/2008
 Tasks:
 Model-based assessment of impacts of ocean acidification on key
biogeochemical and ecosystem processes, including sediment biogeochemistry:
(i) the photic zone: ecosystem structure and productivity, stoichiometry of C
fixation and export production, CaCO3 production, global fluxes of climate
relevant gases, changes in bioavailability of macro-and micronutrients including
sediment biogeochemistry in shelf areas
(ii) the aphotic zone (remineralization of organic carbon, particle aggregation
and ballasting, CaCO3 dissolution, and the rain ratio).
The relative importance of physical versus biological-biogeochemical processes
and their uncertainties will be identified by using sensitivity studies and
probabilistic approaches.