ecological stoichiometry and the paradox of enrichment a new approach to a classical problem n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Ecological stoichiometry and the paradox of enrichment: A new approach to a classical problem PowerPoint Presentation
Download Presentation
Ecological stoichiometry and the paradox of enrichment: A new approach to a classical problem

Loading in 2 Seconds...

play fullscreen
1 / 12

Ecological stoichiometry and the paradox of enrichment: A new approach to a classical problem - PowerPoint PPT Presentation


  • 67 Views
  • Uploaded on

Ecological stoichiometry and the paradox of enrichment: A new approach to a classical problem. Presentation of postdoctoral project Jannicke Moe (Div. of Zoology, Dep. of Biology, University of Oslo, Norway) Also involved: Nils Chr. Stenseth (Div. of Zoology)

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Ecological stoichiometry and the paradox of enrichment: A new approach to a classical problem' - jody


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
ecological stoichiometry and the paradox of enrichment a new approach to a classical problem

Ecological stoichiometry and the paradox of enrichment: A new approach to a classical problem

Presentation of postdoctoral project

Jannicke Moe

(Div. of Zoology, Dep. of Biology,

University of Oslo, Norway)

Also involved:

Nils Chr. Stenseth (Div. of Zoology)

Dag O. Hessen (Div. of Limnology)

Ole Christian Lingjærde (Dep. of Informatics)

daphnia individuals can be measured by image analysis

Image 1

Image 2

Processed image

Daphnia individuals can be measured by image analysis

Information from image analysis:

  • no. of individuals
  • size of individuals
  • condition of individuals (width:length)
  • dead individuals

(Færøvig, Hessen & Andersen 2002)

experimental setup chemostats
Experimental setup: chemostats
  • 2 L bottles containing algae + Daphnia
  • Continuous input of nutrient medium
  • Gradient of input phosphorous concentration
data collection
Data collection
  • Daphnia populations:
    • number of individuals
    • size of individuals ( age / stage)
    • concentrations of P, C and N
  • Algal populations:
    • number algal cells
    • volume of algal cells
    • concentrations of P, C and N
  • Nutrient medium
    • concentrations of P, C and N
lotka volterra models may not be suitable for all consumer resource systems
INTRODUCTIONLotka-Volterra models may not be suitablefor all consumer-resource systems

Predator-prey systems:

  • Resource similar to consumer
  • Energy limiting factor
  • Lotka-Volterra-based models suitable

Herbivore-plant systems:

  • Resource different from consumer
  • Nutrients additional limiting factor
  • Lotka-Volterra-based models less suitable?
a stoichiometric model the daphnia algae phosphorpus system

Consumer quantity Z

(Daphnia carbon biomass)

Resource quantity C

(algal carbon biomass)

Resource quality Q

(algal P content)

Recycling of P

P (phosphorous in environment)

Phosphorous influx PL

BACKGROUND

A stoichiometric model: The Daphnia-algae-phosphorpus system
a stoichiometric model the daphnia algae phosphorpus system1
BACKGROUNDA stoichiometric model: The Daphnia-algae-phosphorpus system

Z = biomass of Daphnia (mg C L-1)

C = biomass of algae (mg C L-1)

P = mass of phosphorous (mg P L-1)

model predictions effect of p enrichment on dynamics

Stable eqilibrium

Unstable equilibrium

Algal isocline

Daphnia isocline

Daphnia (mgC/L)

Algae (mg C/L)

Algae (mg C/L)

BACKGROUND

Model predictions: effect of P enrichment on dynamics

high P influx

Low P influx

aim of experiments different type of population dynamics along p gradient

Algae

Daphnia

Medium P

High P

Plankton biomass

Time

Plankton biomass

Plankton biomass

Time

Time

EXPERIMENTS

Aim of experiments: Different type of population dynamics along P gradient

Low P

problem with stoichiometric model ignores demography
Problem with stoichiometric model: ignores demography

The stoichiometric model does not distinguish between populations with ...

  • equal biomass
  • different number of individuals
  • equal biomass
  • different size structure

Real population

Stoic. model

what type of model is optimal for analysing the daphnia algae system
What type of model is optimal for analysing the Daphnia-algae system?

Population Physiological Stoichiometric

models models models

Limiting factors: energy only energy only energy + nutrients

Currency: no. of ind. ind. biomass total biomass

Density dependence: + - +

Demograpic structures: + - -

An Individual-based population model could consider

  • limitation by energy + nutrients
  • no. of individuals + biomass
  • individuals condition (width:length)
  • density dependence
  • demographic structures (size / stage)
  • demographic stochasticity
ibpm of the daphnia system some challenges
IBPM of the Daphnia system - some challenges
  • Individuals cannot be "recognised" - can data still be used for IBPM?

What kind of assumptions must be made?

  • How can discrete models (IMPB) be combined with continuous models (stoichiometric)?
  • Will an IBPM that includes stoichiometry get too complicated?