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Trophic amplification of climate warming.

Kirby RR, Beaugrand G - Proc. Biol. Sci. (2009)

Bottom Line: Using an end-to-end ecosystem approach that included primary producers, primary, secondary and tertiary consumers, and detritivores, we found that temperature modified the relationships among species through nonlinearities in the ecosystem involving ecological thresholds and trophic amplifications.Trophic amplification provides an alternative mechanism to positive feedback to drive an ecosystem towards a new dynamic regime, which in this case favours jellyfish in the plankton and decapods and detritivores in the benthos.Our results are relevant to ecosystem-based fisheries management (EBFM), seen as the way forward to manage exploited marine ecosystems.

View Article: PubMed Central - PubMed

Affiliation: University of Plymouth, School of Marine Science and Engineering, Drake Circus, Plymouth PL4 8AA, UK. richard.kirby@plymouth.ac.uk

ABSTRACT
Ecosystems can alternate suddenly between contrasting persistent states due to internal processes or external drivers. It is important to understand the mechanisms by which these shifts occur, especially in exploited ecosystems. There have been several abrupt marine ecosystem shifts attributed either to fishing, recent climate change or a combination of these two drivers. We show that temperature has been an important driver of the trophodynamics of the North Sea, a heavily fished marine ecosystem, for nearly 50 years and that a recent pronounced change in temperature established a new ecosystem dynamic regime through a series of internal mechanisms. Using an end-to-end ecosystem approach that included primary producers, primary, secondary and tertiary consumers, and detritivores, we found that temperature modified the relationships among species through nonlinearities in the ecosystem involving ecological thresholds and trophic amplifications. Trophic amplification provides an alternative mechanism to positive feedback to drive an ecosystem towards a new dynamic regime, which in this case favours jellyfish in the plankton and decapods and detritivores in the benthos. Although overfishing is often held responsible for marine ecosystem degeneration, temperature can clearly bring about similar effects. Our results are relevant to ecosystem-based fisheries management (EBFM), seen as the way forward to manage exploited marine ecosystems.

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Related in: MedlinePlus

Sliding correlation analysis between pairs of variables for the period 1958 to 2005. (a) sea surface temperature (SST) and decapods. (b) Decapods and phytoplankton colour index (PCI) with a three-year lag. (c) PCI and C. finmarchicus. (d) Cod SSB and decapods. (e) Decapods and plaice recruits. (f) SST and cod SSB. (g) Decapods and sole recruits. (h) Decapods and bivalves. (i) Echinoderms and bivalves. (j) PCI and total holozooplankton. (k) Jellyfish and holozooplankton (PC1). (l) Jellyfish and C. finmarchicus. Each vertical bar represents a 20 year period, for example, the first three vertical bars represent the overlapping periods 1963 to 1982, 1964 to 1983, and 1965 to 1984, respectively. Consequently, in the axis labels, the upper and lower years denote the beginning and the end of the time period, respectively.
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RSPB20091320F4: Sliding correlation analysis between pairs of variables for the period 1958 to 2005. (a) sea surface temperature (SST) and decapods. (b) Decapods and phytoplankton colour index (PCI) with a three-year lag. (c) PCI and C. finmarchicus. (d) Cod SSB and decapods. (e) Decapods and plaice recruits. (f) SST and cod SSB. (g) Decapods and sole recruits. (h) Decapods and bivalves. (i) Echinoderms and bivalves. (j) PCI and total holozooplankton. (k) Jellyfish and holozooplankton (PC1). (l) Jellyfish and C. finmarchicus. Each vertical bar represents a 20 year period, for example, the first three vertical bars represent the overlapping periods 1963 to 1982, 1964 to 1983, and 1965 to 1984, respectively. Consequently, in the axis labels, the upper and lower years denote the beginning and the end of the time period, respectively.

Mentions: Finally, sliding correlation analysis was applied to assess the temporal stability of the relationships among variables for a time window of 20 years. This approach calculates correlations for moving time periods with an increment of one year. As the technique is sensitive to the chosen time period, windows were examined ranging between 10 and 25 years; these all gave similar conclusions. First, the technique was applied between the first principal component and the 16 biological variables (figure 3). Second, the technique was used on selected pairs of variables (figure 4).


Trophic amplification of climate warming.

Kirby RR, Beaugrand G - Proc. Biol. Sci. (2009)

Sliding correlation analysis between pairs of variables for the period 1958 to 2005. (a) sea surface temperature (SST) and decapods. (b) Decapods and phytoplankton colour index (PCI) with a three-year lag. (c) PCI and C. finmarchicus. (d) Cod SSB and decapods. (e) Decapods and plaice recruits. (f) SST and cod SSB. (g) Decapods and sole recruits. (h) Decapods and bivalves. (i) Echinoderms and bivalves. (j) PCI and total holozooplankton. (k) Jellyfish and holozooplankton (PC1). (l) Jellyfish and C. finmarchicus. Each vertical bar represents a 20 year period, for example, the first three vertical bars represent the overlapping periods 1963 to 1982, 1964 to 1983, and 1965 to 1984, respectively. Consequently, in the axis labels, the upper and lower years denote the beginning and the end of the time period, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2821349&req=5

RSPB20091320F4: Sliding correlation analysis between pairs of variables for the period 1958 to 2005. (a) sea surface temperature (SST) and decapods. (b) Decapods and phytoplankton colour index (PCI) with a three-year lag. (c) PCI and C. finmarchicus. (d) Cod SSB and decapods. (e) Decapods and plaice recruits. (f) SST and cod SSB. (g) Decapods and sole recruits. (h) Decapods and bivalves. (i) Echinoderms and bivalves. (j) PCI and total holozooplankton. (k) Jellyfish and holozooplankton (PC1). (l) Jellyfish and C. finmarchicus. Each vertical bar represents a 20 year period, for example, the first three vertical bars represent the overlapping periods 1963 to 1982, 1964 to 1983, and 1965 to 1984, respectively. Consequently, in the axis labels, the upper and lower years denote the beginning and the end of the time period, respectively.
Mentions: Finally, sliding correlation analysis was applied to assess the temporal stability of the relationships among variables for a time window of 20 years. This approach calculates correlations for moving time periods with an increment of one year. As the technique is sensitive to the chosen time period, windows were examined ranging between 10 and 25 years; these all gave similar conclusions. First, the technique was applied between the first principal component and the 16 biological variables (figure 3). Second, the technique was used on selected pairs of variables (figure 4).

Bottom Line: Using an end-to-end ecosystem approach that included primary producers, primary, secondary and tertiary consumers, and detritivores, we found that temperature modified the relationships among species through nonlinearities in the ecosystem involving ecological thresholds and trophic amplifications.Trophic amplification provides an alternative mechanism to positive feedback to drive an ecosystem towards a new dynamic regime, which in this case favours jellyfish in the plankton and decapods and detritivores in the benthos.Our results are relevant to ecosystem-based fisheries management (EBFM), seen as the way forward to manage exploited marine ecosystems.

View Article: PubMed Central - PubMed

Affiliation: University of Plymouth, School of Marine Science and Engineering, Drake Circus, Plymouth PL4 8AA, UK. richard.kirby@plymouth.ac.uk

ABSTRACT
Ecosystems can alternate suddenly between contrasting persistent states due to internal processes or external drivers. It is important to understand the mechanisms by which these shifts occur, especially in exploited ecosystems. There have been several abrupt marine ecosystem shifts attributed either to fishing, recent climate change or a combination of these two drivers. We show that temperature has been an important driver of the trophodynamics of the North Sea, a heavily fished marine ecosystem, for nearly 50 years and that a recent pronounced change in temperature established a new ecosystem dynamic regime through a series of internal mechanisms. Using an end-to-end ecosystem approach that included primary producers, primary, secondary and tertiary consumers, and detritivores, we found that temperature modified the relationships among species through nonlinearities in the ecosystem involving ecological thresholds and trophic amplifications. Trophic amplification provides an alternative mechanism to positive feedback to drive an ecosystem towards a new dynamic regime, which in this case favours jellyfish in the plankton and decapods and detritivores in the benthos. Although overfishing is often held responsible for marine ecosystem degeneration, temperature can clearly bring about similar effects. Our results are relevant to ecosystem-based fisheries management (EBFM), seen as the way forward to manage exploited marine ecosystems.

Show MeSH
Related in: MedlinePlus