FLEX Station
58°55’N 0°30’E
Depth: 135 m
ICES CM 2010/L:40
27
26
ECOHAM4 - carbon cycle
smalldetritus
carbonateshells(living)
DIC
carbonateshells
(dead)
benthiccalcite
labileDOC semilabile
DOC
1
2
4 Bacteria
largedetritus
6
9
1011
12
13
5
1415
1617
25
2122
18
3
carbonate
system:
CO
CO
HCO
B(OH)
OH
alkalinity
pH
2
3
4
3--
-
-
-
surface
20
2020
bottom
19
28
28 27
27
29diatoms
flagellates
benthicdetritus
microzoo-plankton
mesozoo-plankton
structuredzooplankton
adult
structuredzooplankton
egg-N2
structuredzooplankton
N3-N6
structuredzooplankton
C1-C3
structuredzooplankton
C4-C5
715
For this study the 3D ecosystem model ECOHAM4 has been coupled
to a stage-structure population model parameterised for
according to Stegert 2007. The copepod model includes ten state
variables within five life stages, one for abundance and biomass each.
Carbon-, nitrogen- and phosphors-cycles are each calculated explicitly.
P.elongatus
et al.
The ModelMotivation
The Simulation
Simulations were run for the Northwestern European Continental Shelf (NERC) using
realistic meteorological and hydrographic conditions. To compare the simulated
seasonal zooplankton population dynamics two example stations, one for the
southern North Sea (GLOBEC-Station 32) and one for the northern North Sea (FLEX-
Station), are presented.
Seasonal zooplankton dynamics in the southern and
northern North Sea captured by ecosystem and
stage-structured population models
Christian Lindemann * , Andreas Moll²1,2
,
1) Institute for Hydrobiology and Fisheries Science, University of Hamburg, Hamburg, Germany
2) Institute of Oceanography, University of Hamburg, Hamburg, Germany
3) Institute for Coastal Research, GKSS-Forschungszentrum, Geesthacht, Germany
*Corresponding author: , Tel.: +49 40 42838 5656
Markus Kreus³
GLOBEC Station 32
54°40’N 7°00’E
Depth: 38 m
GLOBEC 32-StationResults
0
1
2
3
4
5
1 51 101 151 201 251 301 351
Time [days]
Bio
mas
s[m
gC
/m³]
Adults
CIV - CV
CI - CIII
NII - NVI
egg - NII
0
1
2
3
4
5
1 51 101 151 201 251 301 351
Time [days]
Bio
mas
s[m
gC
/m³]
Adults
CIV - CV
CI - CIII
NII - NVI
egg - NII
0
5
10
15
20
25
1 51 101 151 201 251 301 351
Time [days]
Bio
mas
s[m
gC
/m³]
Adult
CIV - CV
CI - CIII
NIII - NVI
egg - NII
0
5
10
15
20
25
1 51 101 151 201 251 301 351
Time [days]
Bio
mas
s[m
gC
/m³]
Adult
CIV - CV
CI - CIII
NIII - NVI
egg - NII
Discussion & Outlook
Fig. 1: Carboncycle as implemented in ECOHAM4 incl. Stage-structured population model
Fig. 6: Modeled structured zooplankton abundance at FLEX-Station
Fig. 3: Modeled zooplankton biomass at GLOBEC 32-Station
Fig. 5: Modeled stage-resolved structured zooplankton biomass at GLOBEC 32-StationFig. 4: Modeled stage-resolved structured zooplankton biomass at FLEX-Station
FLEX-Station
Fig. 2: Modeled zooplankton biomass at FLEX-Station
Fig. 7: Modeled structured zooplankton abundance at GLOBEC 32-Station
Preliminary model results indicated, that general
zooplankton dynamics and the seasonal population
dynamics of in the northern and southern
North Sea vary significantly, mostly due to different
hydrological condition.
The northern area being stratified during summer,
exhibited two peaks in zooplankton biomass, correlating
to spring and autumn phytobloom.
For the southern area the zooplankton biomass peaked
at the end of July. This peak was more pronounced in
the “bulk” formulation than in structured zooplankton,
indicating the different behavior of the respective model
compartments.
Overall zooplankton biomass in the northern North Sea
was estimated to be approx. five times as high as in the
southern North Sea.
For the FLEX- position the model calculated four
generations per year, while shortened generation time
for the southern North Sea lead to five generations.
P. elongatus
References!
!
!
!
Corkett, C.J. & McLaren, I.A. (1978) The biology of Pseudocalanus; Advances in Marine Biology; 15, 1-231.
Harris, R.P. and Paffenhöfer, G.-A.(1976) The effect of food concentration on cumulative ingestion and growth efficiency of two small marine planktonic copepods; Journal of the Marine Biological Association of the United Kingdom; 56: 875-888.
Renz, J., Mengedoth, D. and Hirche, H.-J. (2008) Reproduction, growth and secondary production of Pseudocalanus elongatus Boeck (Copepoda, Calanoida) in the southern North Sea; Journal of Plankton Research; 30(5): 511-528.
Stegert, C., Kreus, M., Carlotti, F., Moll A. (2007) Parameterisation of a zooplankton population model for Pseudocalanus elongatus using stage durations from laboratory experiments; Ecological modelling 206; 213230.
The seasonal zooplankton dynamics of marine systems are characterized by a few
key players. In the North Sea one of these species is
(Boeck, 1865), a calanoid copepod displaying different seasonal dynamics in
northern and southern areas of that ecosystem.
Those population dynamics are possibly best captured by models using an explicit
approach of structured population as opposed to merely a “bulk” zooplankton
formulation.
The strong influence of physical properties on plankton ecology put forward the
importance of spatially-explicit models, especially in the light of changing
environmental conditions, such as climate change.
Thus, a combined approach is likely to give better and more holistic representation
of zooplankton population dynamics.
Pseudocalanus elongatus
The model displayed differences between the “bulk” and stage-structured formulation not only in relative biomass, but also in dynamic
behavior.
In general the structured population model appears to be an appropriate tool for the investigation of specific populations.
The trade-off however, is a higher model complexity and computational costs. Autumn production still seems to be overestimated by the
stage-structured model. Thus improvement towards this end and the inclusion of adaptive capabilities would further strengthen this model.
The modeled zooplankton biomass (Harris & Paffenhöfer, 1976), as well as the numbers of generations predicted by the
structured population model (Corkett & McLaren, 1978; Renz et al., 2008), was within the range of observed values described in literature.
Acknowledgements
We are thankfull for the help and advice
from Ina Lorkowski, Myron Peck
and Johannes Pätsch.
Funding for the research was received
from the DFG funded AQUASHIFT
project via the"RECONN" project
as well as the CliSAP Cluster of Excellence.
This poster presentation is supported
by a ICES travel fund for early-career
scientists.
.