Environmental controls on the elemental composition of a Southern Hemisphere strain of the coccolithophore <i>Emiliania huxleyi</i>
A series of semi-continuous incubation experiments were conducted with the coccolithophore <i>Emiliania huxleyi</i> strain NIWA1108 (Southern Ocean isolate) to examine the effects of five environmental drivers (nitrate and phosphate concentrations, irradiance, temperature, and partial...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-01-01
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| Series: | Biogeosciences |
| Online Access: | https://www.biogeosciences.net/15/581/2018/bg-15-581-2018.pdf |
| Summary: | A series of semi-continuous incubation experiments were conducted with the
coccolithophore <i>Emiliania huxleyi</i> strain NIWA1108 (Southern Ocean
isolate) to examine the effects of five environmental drivers (nitrate and
phosphate concentrations, irradiance, temperature, and partial pressure of
CO<sub>2</sub> (<i>p</i>CO<sub>2</sub>)) on both the physiological rates and elemental
composition of the coccolithophore. Here, we report the alteration of the
elemental composition of <i>E. huxleyi</i> in response to the changes in
these environmental drivers. A series of dose–response curves for the
cellular elemental composition of <i>E. huxleyi</i> were fitted for each of
the five drivers across an environmentally representative gradient. The
importance of each driver in regulating the elemental composition of
<i>E. huxleyi</i> was ranked using a semi-quantitative approach. The
percentage variations in elemental composition arising from the change in
each driver between present-day and model-projected conditions for the year
2100 were calculated. Temperature was the most important driver controlling
both cellular particulate organic and inorganic carbon content, whereas
nutrient concentrations were the most important regulator of cellular
particulate nitrogen and phosphorus of <i>E. huxleyi</i>. In contrast,
elevated <i>p</i>CO<sub>2</sub> had the greatest influence on cellular particulate
inorganic carbon to organic carbon ratio, resulting in a decrease in the
ratio. Our results indicate that the different environmental drivers play
specific roles in regulating the elemental composition of <i>E. huxleyi</i>
with wide-reaching implications for coccolithophore-related marine
biogeochemical cycles, as a consequence of the regulation of <i>E.
huxleyi</i> physiological processes. |
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| ISSN: | 1726-4170 1726-4189 |