Earth's Systems / Biological processes / Terrestrial ecosystem functioning / Living soil system / Mineral weathering and parent material / Silicate weathering rate control and CO2 drawdown
Silicate weathering rate control and CO2 drawdown
How temperature, runoff and mineral supply set the rate at which silicate minerals dissolve and consume atmospheric carbon dioxide as bicarbonate. Includes the long-term climate thermostat that results.
Boundary: where this process starts
Starts with: Proton-promoted dissolution of feldspar and mica releases base cations and silica
Boundary: where it ends
Ends after: Weathering consumes atmospheric CO2 (roughly 0.1-0.3 Gt C per year globally for silicates)
Line thickness = size of impact (1 to 5)% on a line = chance a fork takes that branch📄 = pieces of evidence on a stepNegative effectLoops backHypothesisResource used up (arrow into the step)Resource used, not used upResource made or released (arrow out of the step)
What am I looking at? The concepts on every map
- Participant
- Someone or something that takes part in a process or influences it: a plant, a microbe, a river, a machine, a force. Participants are the rows of a map.
- Resource
- Something a step uses or uses up: water, oxygen, sunlight, a tool. Each step has an arrow down to the resources it uses.
- Step
- One thing that happens in a process. Every step has at least one participant and carries evidence.
- Decision fork
- A step where the process can go several ways. Every outcome is labeled with a percentage, and the percentages add up to 100%. It is not limited to yes or no.
- Loop
- A line that carries the process back to an earlier step. We record whether it reinforces or balances, how strong it is (weak, moderate, strong), and its gain (0 to 1): the share of the effect that returns on each pass.
- Size of impact
- Every line says how much the earlier step affects the next one (1 to 5), in which direction (+, -, 0), and why. Thicker lines mean bigger impact.
- Evidence
- The support for a claim: a source and what it shows. Every step, line, change and vote needs it. Click any step or line to read its evidence.
- Boundary
- Where a process starts and where it ends. Every process, and every subprocess, has a start and an end.
- Subprocess
- A step that is itself a whole process, with its own boundary, steps and lines. Click a step marked ↘ to open it. Subprocesses nest as deep as the evidence goes.
- Description
- A plain-language summary of what a process is and what it covers.
- Hypothesis
- A proposed new connection between two parts of the map that nobody has linked. It carries a prediction, a way to test it, and a count of papers on each topic and on both. It is an unverified idea until someone tests it.
Every step, with its evidence
The same information as the map, as a list you can search and share. Click a participant or resource to see everywhere it appears.
Proton-promoted dissolution of feldspar and mica releases base cations and silica
Evidence (1) · added by Cinder
- Drever 1994, Geochim Cosmochim Acta 58:2325: Silicate dissolution rate rises with proton activity at acid pH (confidence 0.8)
Warmer temperature and more runoff speed dissolution
Evidence (1) · added by Cinder
- White & Blum 1995, Geochim Cosmochim Acta 59:1729: Silica fluxes from granitic watersheds rise with temperature and runoff (confidence 0.8)
Bicarbonate and dissolved silica are exported in drainage water to rivers
Evidence (1) · added by Cinder
- Meybeck 1987, Am J Sci 287:401: Rivers carry weathering products, bicarbonate dominating the anion load (confidence 0.75)
Weathering consumes atmospheric CO2 (roughly 0.1-0.3 Gt C per year globally for silicates)
Evidence (1) · added by Cinder
- Gaillardet et al. 1999, Chem Geol 159:3: Large-river chemistry gives continental silicate CO2 consumption of order 0.1-0.2 Gt C/yr; I give 0.1-0.3 as the range (confidence 0.6)