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Marine phytoplankton acts as a considerable sink of atmospheric CO 2 as it sequesters large quantities of this greenhouse gas for biomass production. To assess microalgae's counterbalancing of global warming, the quantities of CO 2 they fix need to be determined. For this task, it is mandatory to understand which environmental and physiological parameters govern this transformation from atmospheric CO 2 to microalgal biomass. However, experimental analyses are challenging as it has been found that the chemical environment has a major impact on the physiological properties of the microalgae cells (diameter typ. 5–20 μm). Moreover, the cells can only chemically interact with their immediate vicinity and thus compound sequestration needs to be studied on a microscopic spatial scale. Due to these reasons, computer simulations are a more promising approach than the experimental studies. Modeling software has been developed that describes the dissolution of atmospheric CO 2 into oceans followed by the formation of HCO 3 − which is then transported to individual microalgae cells. The second portion of this model describes the competition of different cell species for this HCO 3 − , a nutrient, as well as its uptake and utilization for cell production. Two microalgae species, i.e. Dunaliella salina and Nannochloropsis oculata , were cultured individually and in a competition situation under different atmospheric CO 2 conditions. It is shown that this novel model's predictions of biomass production are in very good agreement with the experimental flow cytometry results. After model validation, it has been applied to long-term prediction of phytoplankton generation. These investigations were motivated by the question whether or not cell production slows down as cultures grow. This is of relevance as a reduced cell production rate means that the increase in a culture's CO 2 -sinking capacity slows down as well. One implication resulting from this is that an increase in anthropogenic CO 2 may not be counterbalanced by an increase in phytoplankton production. Modeling studies have found that for several different atmospheric CO 2 levels provided to single-species cultures as well as to species in competing scenarios the cell production rate does slow down over time.
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Quantitative modeling of microalgae based sequestration of atmospheric CO 2
Marine microalgae have been identified as a considerable sink of atmospheric CO 2 . Since macroscopic ecosystems cannot be studied experimentally with the required microscopic spatial resolution, a novel modeling method is being presented to quantify this sequestration process. The presented modeling studies indicate that the fixation of carbon by microalgae is species-specific and depends on competition effects among multiple species.
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- Award ID(s):
- 1710175
- PAR ID:
- 10057150
- Date Published:
- Journal Name:
- The Analyst
- Volume:
- 143
- Issue:
- 5
- ISSN:
- 0003-2654
- Page Range / eLocation ID:
- 1042 to 1045
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/c7an01781b
