D4.2.4 Use of a model to investigate the effect of variables on ecosystem stability Notes

Mesocosms Simulate Ecosystem Processes in a Controlled Setting

1. If you were tasked with creating a miniature ecosystem in a jar.
2. How would you ensure it remains stable over time?
3. This is the essence of mesocosms which are controlled environments that model natural ecosystems.

Key Elements Make Mesocosms Function

1. To create a sustainable mesocosm, all essential components of an ecosystem must be included:
   1. Autotrophs: Plants or algae to produce oxygen and organic matter.
   2. Consumers: Herbivores and carnivores to simulate food webs.
   3. Decomposers: Bacteria and fungi to recycle nutrients.
   4. Abiotic Factors: Soil, water, light, and temperature to maintain stability.

Sealed Mesocosms Create Closed Systems for Testing

1. Mesocosms can be sealed or open, depending on the experiment’s objectives:
   1. Sealed Mesocosms: Allow energy transfer (e.g., sunlight) but prevent matter exchange, ideal for long-term studies.
   2. Open Mesocosms: Interact with external environments and are useful for studying specific variables like pollution.

Strengths of Mesocosms

1. Controlled Variables Enable Precise Testing: Scientists can manipulate environmental factors to test specific hypotheses.
2. Replicability Supports Reliable Results: Experiments in mesocosms can be repeated to confirm findings.
3. Scalability Fits Various Research Goals: Mesocosms range in size from small jars to large outdoor tanks, making them versatile.

Limitations of Mesocosms

1. Simplified Systems May Miss Complex Interactions: Mesocosms cannot fully replicate the diversity and complexity of natural ecosystems.
2. Small Size Restricts Observation of Larger Processes: Smaller mesocosms may fail to capture large-scale ecological dynamics.
3. Edge Effects May Skew Results: Boundaries of mesocosms can alter the behavior of organisms or disrupt natural processes.