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Updated: Apr 13, 2026
11:19
Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses
Published on: October 21, 2016
12.5K
Modeling the carbon cycle in Lake Matano.
L B Kuntz1, T A Laakso1, D P Schrag1
1Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA.
Geobiology
|April 30, 2015
Summary
This study models Lake Matano
Area of Science:
- Geochemistry
- Microbial Ecology
- Paleoceanography
Background:
- Lake Matano, Indonesia, an anoxic, iron-rich lake, serves as an analog for early Earth oceans.
- Previous research indicated high methane production, yet isotopic data presented a contradiction.
- Discrepancies existed between observed methane production and dissolved inorganic carbon (DIC) isotopic values.
Purpose of the Study:
- To reconcile conflicting data on methane production and carbon isotopes in Lake Matano.
- To develop a carbon cycle model for this ferruginous lake.
- To reassess the role of methanogenesis and iron respiration in ancient oceans.
Main Methods:
- Developed a box model of Lake Matano's carbon cycle.
- Incorporated constraints from methane (CH4) and DIC isotopic profiles.
- Included sediment composition and alkalinity data.
Main Results:
- Estimated smaller methane fluxes than previously suggested.
- Found methanogenesis degrades approximately 9% of organic carbon export.
- Anoxic ferric iron respiration degrades less than 3% of organic carbon export.
Conclusions:
- Methanogenesis is the dominant anaerobic remineralization pathway in Lake Matano.
- Iron plays a minor role as an electron acceptor in this system.
- The significance of methane in early Earth oceans may be less than previously assumed.
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