A microscopic image of Coccolithophores

Environmental Effects on Coccolithophores

The effects of light, macronutrients, trace metals and CO2 on the
production of calcium carbonate and organic carbon in coccolithophores—A review
by Ingrid Zondervan

Zondervan, Ingrid. (2007). The effects of light, macronutrients, trace metals and CO2 on the production of calcium carbonate and organic carbon in coccolithophores—A review. Deep Sea Research Part II: Topical Studies in Oceanography. 54. 521-537. 10.1016/j.dsr2.2006.12.004.

Annotated Bibliography

Summary:

This paper provided a literature review on the the species coccolithophores. They looked at multiple aspect of the coccolithophores mostly in respect to how it calcifies under different environments. In the end for E. huxleyi the main factor for blooming was the lighting conditions both for photosynthesis and for calcification however calcification requires lower light levels.

Methodology:

Since this was a literature review not much can be pointed out in their methodology. They included many papers to provided different perspectives and also mention when limitations might have occurred. One interesting technique the paper did mention was to indefinitely the density of E. huxleyi, the main species in question, since it backscatters a significant amount of light you can estimate how dense/how many blooms their are based on how bright the water is from a satellite. On a separate note they also include how a paper tested the calcification rates under pCO2. Through their testing they only need 1.5-9 days in order for results to be found and they refuted possible skepticism for the time period by stating that the authors found no difference in calciation in the short versus long term.

Questions:

The main criticism that can be found throughout the paper is the lack of discussion that pH levels or temperature has in growth rates or calcification. The paper admits to this fact but again refutes this claim by stating that the species they were looking at, E. huxleyi, is “eurythermal and euryhaline” meaning that it is resistant to temperature change and acidity. 

Use/Relevance:

Due to this paper being for ocean modeller who do not know much about coccolithophores the paper provided ample amount of fundamental information. It clearly outlined the chemical process of calcification as well as how phytoplankton can transform the new CO2 substance into glucose, water, and  oxygen. As mentioned before the paper took many different perspectives and the first of which is light and how different species within the coccolithophore group can photosynthesis and calcify under different conditions which is helpful to keep in mind for conducting experiments with other photosynthetic species. After light there was discussion on trace mineral such as iron, zinc, cobalt, phosphate, and nitrogen. It was found that cobalt and zinc were replaceable in order for the species to survive. Iron, which alongside zinc has decreased by a factor of 10 since glacial period, is a limiting factor in phytoplankton so when conducting an experiment iron could be a factor to test. Similarly, zinc has been found to limit growth in coccolithophores specifically but E. huxleyi does not require much iron to growth which allows it to fill gaps in ecosystems that lack iron concentrations. Finally most pertinent to the ocean acidification conversation is the affect of CO2. The paper included an experiment that found that “calcification diminished by 10-19% in E. huxleyi and by 66% in G. oceanica.”

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