227
sedimentation of a large fraction of these diatoms. We identified the association of POPs to phytoplankton during the
phytoplankton bloom and subsequent co-sedimentation as
the main pathway of transport of POPs from the pelagic to
the benthic system. Subsequently the lipophilicity of the
POP is the main contributor to the fractional flux of POPs
from the pelagic to the benthic system.
10 Ecosystems Dynamics in a Changing
World: Regime Shifts and Resilience
in Marine Communities
Camilla Sguotti
1
and Xochitl Cormon
1
1
Institute for Hydrobiology and Fisheries Science, Centre
for Earth System Research and Sustainability (CEN),
University of Hamburg, Germany
10.1 Call for Abstracts
Over the last decades many marine ecosystems and fish populations all over the world have undergone drastic changes,
termed regime shifts, because of the additive effects of
anthropogenic and natural stressors. We invite you to present: (1) Studies related to marine ecosystems structure and
population dynamics (i.e., food-webs, spatial distribution,
regulating processes, top-down and/or bottom-up), as well as
potential drivers of regime shifts. (2) Examples of shifts and
resilience of ecosystems and studies comparing regimes
across different scales (temporal or spatial). (3) Studies
investigating impacts of regime shifts on ecosystem services
and potential implications for management and
stakeholders.
10.2 Abstracts of Oral Presentations
10.2.1 Regime Shift, a Global Challenge
for the Sustainable Use of our Marine Resources
Camilla Sguotti
1*
, Xochitl Cormon
1*
1
Institute for Hydrobiology and Fisheries Science, Centre
for Earth System Research and Sustainability (CEN),
University of Hamburg, Germany
*corresponding authors: camilla.sguotti@uni-hamburg.
de, xochitl.cormon@uni-hamburg.de
Over the last decades many marine ecosystems and fish
populations have undergone drastic changes often resulting
in new, ecologically poorer and/or economically less valuable states. In particular, the additive effects of anthropogenic (e.g., fishing, climate change) and natural stressors
(e.g., natural variability) seem to play a fundamental role in
causing unexpected and sudden shifts between ecosystem
states, generally termed regime shifts. Recently, many examples of regime shifts have been documented world-wide and
their mechanisms and consequences have been vigorously
discussed. Understanding causes and mechanisms of regime
shifts is of great importance for the sustainable use of natural
resources and their management, especially in marine ecosystems. In this session titled “Ecosystem dynamics in a
changing world, regime shifts and resilience in marine communities” during the 8th YOUMARES conference (Kiel,
13–15th September 2017) we will present regime shifts and
associated concepts to a broad range of marine scientists (not
only biologists and/or ecologists) and highlight their importance for the marine ecosystems worldwide.
10.2.2 Regime Shift Analysis in Atlantic Herring
Stocks
Leonie Färber
1*
, Camilla Sguotti
2
, Saskia A. Otto
2
, Christian
Möllmann
2
1
Centre for Ecological and Evolutionary Synthesis
(CEES), Department of Biosciences, University of Oslo, PO
Box 1066 Blindern, N-0316 Oslo, Norway
2
Institute for Hydrobiology and Fisheries Science,
University of Hamburg, Grosse Elbstrasse 133, 22767
Hamburg, Germany
*corresponding author: l.a.farber@ibv.uio.no
Keywords: Atlantic herring, Clupea harengus, Regime
shift
External drivers such as temperature, nutrient loadings,
habitat exploitation or fragmentation have profound effects
on marine ecosystem dynamics playing a major role in
observed large-scale changes. Those changes can happen
gradually and linearly or abruptly and discontinuously, as
observed in ecological regime shifts. For instance, many
fish stocks experienced a strong depletion over time and
some stocks might have undergone one or several abrupt
shifts. In this work, 16 herring (Clupea harengus) stocks
from the Atlantic, the North and Baltic Sea were analyzed
for the detection of possible regime shifts. Herring is a commercially important species and the understanding of its
dynamics is essential for management purposes. In specific,
a trend change analysis was conducted, combined with a
Bayesian change point analysis (bcp) in order to find possible sudden collapses in the spawning stock biomass (SSB)
and recruitment (R). Only a few of the stocks showed a prolonged depletion in their SSB and hardly any changes in the
recruitment during the time series. Most of the dynamics
can be considered as natural fluctuations. Multiple statistical analyses were conducted in order to find the underlying
drivers causing interannual fluctuations and, if existing, the
collapse. Indices of large-scale climatic fluctuations, i.e.,
the North Atlantic Oscillation (NAO), the Atlantic
Multidecadal Oscillation (AMO) index, the Sea Surface
Temperature (SST) and fishery mortality were used as
Appendices
sedimentation of a large fraction of these diatoms. We identified the association of POPs to phytoplankton during the
phytoplankton bloom and subsequent co-sedimentation as
the main pathway of transport of POPs from the pelagic to
the benthic system. Subsequently the lipophilicity of the
POP is the main contributor to the fractional flux of POPs
from the pelagic to the benthic system.
10 Ecosystems Dynamics in a Changing
World: Regime Shifts and Resilience
in Marine Communities
Camilla Sguotti
1
and Xochitl Cormon
1
1
Institute for Hydrobiology and Fisheries Science, Centre
for Earth System Research and Sustainability (CEN),
University of Hamburg, Germany
10.1 Call for Abstracts
Over the last decades many marine ecosystems and fish populations all over the world have undergone drastic changes,
termed regime shifts, because of the additive effects of
anthropogenic and natural stressors. We invite you to present: (1) Studies related to marine ecosystems structure and
population dynamics (i.e., food-webs, spatial distribution,
regulating processes, top-down and/or bottom-up), as well as
potential drivers of regime shifts. (2) Examples of shifts and
resilience of ecosystems and studies comparing regimes
across different scales (temporal or spatial). (3) Studies
investigating impacts of regime shifts on ecosystem services
and potential implications for management and
stakeholders.
10.2 Abstracts of Oral Presentations
10.2.1 Regime Shift, a Global Challenge
for the Sustainable Use of our Marine Resources
Camilla Sguotti
1*
, Xochitl Cormon
1*
1
Institute for Hydrobiology and Fisheries Science, Centre
for Earth System Research and Sustainability (CEN),
University of Hamburg, Germany
*corresponding authors: camilla.sguotti@uni-hamburg.
de, xochitl.cormon@uni-hamburg.de
Over the last decades many marine ecosystems and fish
populations have undergone drastic changes often resulting
in new, ecologically poorer and/or economically less valuable states. In particular, the additive effects of anthropogenic (e.g., fishing, climate change) and natural stressors
(e.g., natural variability) seem to play a fundamental role in
causing unexpected and sudden shifts between ecosystem
states, generally termed regime shifts. Recently, many examples of regime shifts have been documented world-wide and
their mechanisms and consequences have been vigorously
discussed. Understanding causes and mechanisms of regime
shifts is of great importance for the sustainable use of natural
resources and their management, especially in marine ecosystems. In this session titled “Ecosystem dynamics in a
changing world, regime shifts and resilience in marine communities” during the 8th YOUMARES conference (Kiel,
13–15th September 2017) we will present regime shifts and
associated concepts to a broad range of marine scientists (not
only biologists and/or ecologists) and highlight their importance for the marine ecosystems worldwide.
10.2.2 Regime Shift Analysis in Atlantic Herring
Stocks
Leonie Färber
1*
, Camilla Sguotti
2
, Saskia A. Otto
2
, Christian
Möllmann
2
1
Centre for Ecological and Evolutionary Synthesis
(CEES), Department of Biosciences, University of Oslo, PO
Box 1066 Blindern, N-0316 Oslo, Norway
2
Institute for Hydrobiology and Fisheries Science,
University of Hamburg, Grosse Elbstrasse 133, 22767
Hamburg, Germany
*corresponding author: l.a.farber@ibv.uio.no
Keywords: Atlantic herring, Clupea harengus, Regime
shift
External drivers such as temperature, nutrient loadings,
habitat exploitation or fragmentation have profound effects
on marine ecosystem dynamics playing a major role in
observed large-scale changes. Those changes can happen
gradually and linearly or abruptly and discontinuously, as
observed in ecological regime shifts. For instance, many
fish stocks experienced a strong depletion over time and
some stocks might have undergone one or several abrupt
shifts. In this work, 16 herring (Clupea harengus) stocks
from the Atlantic, the North and Baltic Sea were analyzed
for the detection of possible regime shifts. Herring is a commercially important species and the understanding of its
dynamics is essential for management purposes. In specific,
a trend change analysis was conducted, combined with a
Bayesian change point analysis (bcp) in order to find possible sudden collapses in the spawning stock biomass (SSB)
and recruitment (R). Only a few of the stocks showed a prolonged depletion in their SSB and hardly any changes in the
recruitment during the time series. Most of the dynamics
can be considered as natural fluctuations. Multiple statistical analyses were conducted in order to find the underlying
drivers causing interannual fluctuations and, if existing, the
collapse. Indices of large-scale climatic fluctuations, i.e.,
the North Atlantic Oscillation (NAO), the Atlantic
Multidecadal Oscillation (AMO) index, the Sea Surface
Temperature (SST) and fishery mortality were used as
Appendices