CO2 alters community composition and response to nutrient enrichment of freshwater phytoplankton

Abstract

Nutrients can limit the productivity of ecosystems and control the composition of the communities of organisms that inhabit them. Humans are causing atmospheric CO2 concentrations to reach levels higher than those of the past millions of years while at the same time propagating eutrophication through the addition of nutrients to lakes and rivers. We studied the effect of elevated CO2 concentrations, nutrient addition and their interaction in a series of freshwater mesocosm experiments using a factorial design. Our results highlight the important role of CO2 in shaping phytoplankton communities and their response to nutrient addition. We found that CO2 greatly magnified the increase in phytoplankton growth caused by the increased availability of nutrients. Elevated CO2 also caused changes in phytoplankton community composition. As predicted from physiology and laboratory experiments, the taxonomic group that was most limited by current day CO2 concentrations, chlorophytes, increased in relative frequency at elevated CO2. This predictable change in community composition with changes in CO2 is not altered by changes in the availability of other nutrients.

Ecophysiology matters: linking inorganic carbon acquisition to ecological preference in four species of microalgae (Chlorophyceae)

“…, Low‐Decarie et al. ), as well as on intrinsic ecophysiological characteristics. Species which are able to use HCO 3 − in addition to CO 2 will be at an advantage at high pH by being less dependent on CO 2 availability.…”

“…) and increase in phytoplankton biomass (Low‐Decarie et al. ). Although if lake concentrations of CO 2 are determined by the catchment (Maberly et al.…”

Communities that thrive in extreme conditions captured from a freshwater lake

“…0.5, no detectable salinity 0.00 ppt, conductivity 80.9 + s.d. 9.1 mS cm 21 [15]). Our ABRs were set up to enrich for microalgae through the provision of light (continuous approx.…”

Surface water CO2 concentration influences phytoplankton production but not community composition across boreal lakes

“…), and recent experimental work (Low‐Decarie et al . , ) and paleolimnological reconstructions (Wolfe & Siver ) have suggested that phytoplankton community composition may vary along CO 2 concentration gradients (Low‐Decarie et al . ).…”

“…; Low‐Decarie et al . , , ; Jansson et al . ) work has suggested that increases in ambient CO 2 relative to current atmospheric equilibrium could influence algal performance and therefore whole ecosystem primary production (Urabe et al .…”