Transcript Zooplankton feeding types in a global biogeochemical ocean model Friederike Prowe [email protected] Ken H.

Zooplankton feeding types
in a global biogeochemical ocean model
Friederike Prowe
[email protected]
Ken H. Andersen, Thomas Kiørboe, Andre W. Visser
DTU Aqua
Stephanie Dutkiewicz, Mick Follows
MIT
45th Liège Colloquium - 16.05.2013
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Why focus on zooplankton?
NABE ‘89
Prowe et al. 2012
2
Why focus on zooplankton?
NABE ‘89
type 2
Prowe et al. 2012
type 3 high
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Why focus on zooplankton?
Grazing influences

diversity, community composition, succession

PP, export
type 2
Prowe et al. 2012
type 3 high
4
Zooplankton feeding
type 2 (Disc equation)


fixed preferences
two zooplankton types
type 3 (sigmoidal)


variable preferences
implicit specialist community
Encounters: traits & trade-offs
v
− low
R2

size

feeding mode:
re ~ R2 v
v
search area
high +
+ large
encounter rate
high −
− low
predation risk
+ low
ambushers
R2
cruisers
high +
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Zooplankton feeding
type 2 (Disc equation)


fixed preferences
two zooplankton types
type 3 (sigmoidal)


variable preferences
implicit specialist community
Encounters: traits & trade-offs
v
− low
R2

size

feeding mode:
re ~ R2 v
v
search area
high +
+ large
encounter rate
high −
− low
predation risk
+ low
ambushers
R2
cruisers
high +
6
Zooplankton feeding
type 2 (Disc equation)


fixed preferences
two zooplankton types
type 3 (sigmoidal)


variable preferences
implicit specialist community
Encounters: traits & trade-offs
v
− low
R2

size

feeding mode:
re ~ R2 v
v
search area
high +
+ large
encounter rate
high −
− low
predation risk
+ low
ambushers
R2
cruisers
high +
7
Feeding interactions
size preference
(encounter rates)
size & motility
traditional model
encounter model
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Feeding interactions
size preference
(encounter rates)
size & motility
traditional model
encounter model
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Results: type biogeography

distinct biogeography

complex interactions: emergent food web

abstract PFTs: comparison with other PFT
estimates difficult
... generate hypotheses!
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Zooplankton biomass
how to assess predictions?
doi:10.1594/PANGAEA.785501
doi:10.1594/PANGAEA.779970
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Primary production
parameter sensitivity:
higher mortality for
large cruiser
%
%
%
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Primary production
parameter sensitivity:
higher mortality for
large cruiser
%
%
%
13
Primary production
... but really:
should look at seasonal data

not too coastal

species resolution

if possible, not just copepods

CPR (North Atlantic)

BATS, HOT, etc.

do you know more?
%
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Zooplankton community composition
from the COPEPOD data base (http://www.st.nmfs.noaa.gov/copepod/)
Oithona sp. as proxy for large ambusher:

subgroup copepods

only cruises/stations with Oithona listed

Oithona sp. abundance fraction of all taxa sampled at that station
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A new global model

mechanistic trait-based trophic interactions for plankton

trades off feeding strategy against predation risk for different prey sources

explicit community, emergent food web
Summary
... to generate hypotheses about

zoo PFT biogeography

seasonal succession

trophic web efficiency

effect on ocean functions: PP, export
Assessment?

on the global scale: data limitations

regional: AMT, COPEPOD

seasonal: CPR data North Atlantic, time series sites

Do you have more data?
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Zooplankton community composition
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Why focus on zooplankton?
NABE ‘89
type 2
type 3 high
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Why focus on zooplankton?
Global coupled ocean ecosystem model

4 nutrients, 78 phyto, 2 zoo, DOM, POM

advection, mixing (3D MITgcm, 1° grid)

self-assembling phyto community

type 2
4 PFTs (diatoms, other large,
prochlorococcus, other small)
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Seasonal succession
higher mortality for large cruiser
Large Motile
Large Non-motile
small motile
small non-motile
standard
Phyto
month
month
Zoo
month
month
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