First drafted 2006-02-15. Last updated 2006-02-16. Version 0.0.3

Ecology and Global Change

Andy Turner


Ecology and global change (EGC) is as intersting as it is important. The SoG has had an EGC Research Cluster since the beginning of 2005. My notes from EGC Research Cluster Meetings .

I began research work on climate change in 1997 for the Mediterranean Desertification and Land Use Project MEDALUS III . This work I contnues through the MedAction and DesertLinks projects

These projects all focused on a process called land degradation. A focus was to address the task of how to simulated or model Earth, so as to forecast changes in the medium to long term? This is an ongoing challenge. Given the merits of SimEarth as released in 1990, can we do better? Something more scientific... What shall it be called? How about GeoSim?

Gaia and Evolutionary Biology

The Gaia Hypothesis proposes that planet Earth functions as a single organism maintaining conditions necessary for life.

"Life, or the biosphere, regulates or maintains the climate and the atmospheric composition at an optimum for itself." (Lovelock, 1979)

For there to be organisms, there were conditions for life and replication. Primary organisms harvest heat or light energy and process it within a membrane. Replication is then produces cultures of primary organisms. Organisms then adapt through evolutionary processes to take advantage of the environment left by other organisms.

The biosphere, atmosphere, lithosphere and hydrosphere all interact. Sometimes the interactions result in mass extinctions, biological evolution, ice ages, sea level changes, techtonic plate movements, volcanes etc... All these things are fascinating.

There is a beautiful carbon, hydrogen and oxygen balance due to photosynthesis and respiration. All it requires is energy and capable organisms. Carbon dioxide and water are taken in and sugar and oxygen produced in photosynthesis. Sugar and oxygen are taken in and carbon dioxide and water produced in respiration. Photosythesis is about storing energy and respiration is about releasing it. Both processes require energy and the thermodynamic laws apply.

Is is likely that significant cultures of organisms that only respire evolved only after there were primary organisms for them to consume. At an early stage, it is likely that chemistry was altered by the ecosystem such that oxygen levels in the gaseous atmosphere significantly increased. A limit at which the atmosphere is explosive would have been approached. At some stage the ecosytem balanced things out in line with the photosythesis and respiration balance.

Many now argue that the balance is again unstable and that something fundamental, the temperture of the Earth's surface and atmosphere, is increasing at an alarming rate due to a greenhouse effect. The greenhouse effect is a result of carbon dioxide in the atmosphere acting like the a greenhouse allowing more suns energy in than it allows heat energy out. It is suggested that the burning of fossil fuels is driving the levels of atmospheric carbon dioxide to the highest levels recorded. This is very likely the case. All measurements of atmospheric carbon dioxide that scientists have made support this.

Carbon Balance

Contentious Hypothesis?

There is an assumption in ecological work that the amount of carbon that is returned from the atmosphere in precipitation is negligible. I wonder if this is really the case. A hypothesis: Although photosynthetic uptake of carbon is perhaps greater, the amount of carbon returned from the atmosphere in precipitation can be significant.

What organisations are looking at this? What are the estimates?

After a fire much ash returns to earth if it rains. Presumably this contributes to carbon levels in soil. Potentailly some of it may be taken up by plants and some may be washed into rivers and oceans.

What about the solubility of carbon dioxide and the formation of carbonic acid and dissolved carbon?

Boreal See references...



Pia Wohland speciality. See My notes from EGC Research Cluster Meeting 2006-02-15


2006-02-16 Chris Freeman (University of Bangor) Peatland Enzymes and the Carbon Cycle

Carbon sinks due to decompostion not working.

Potentially very important.

What happens if you dry out peatlands? They release carbon in the form of carbon dioxide... What exactly is causing this? Micro-organisms... Enzyme production for breaking down organic matter is the key... Done by direct measurements of enzyme activity.

Lack of research in wetlands on enzyme activity compared with other ecosystems.

It is the phenolic compounds in peat that prevent the normal runaway process of denaturisation (decompostion). Lack of oxygen inhibits (phenoloxidaze) enzymes that break down phenolic compounds.

What are the impacts of climate change? Warming stimulates decompostion. Carbon dioxide increase encourages plant growth. Peatlnads become carbon sources? Dissolved organic carbon exports from peatland is on the rise. Where is it going? Is it carbon in, carbon out?

Chris Keylock outlined a laboratory experiment on looking at the effects of phenoloxidaze etc... Generally agreed this would be a good idea!

Phenolics is humic acid.

Google:Wetzel ecology wetlands



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