Data from: Impact of temperature and nutrients on carbon: nutrient tissue stoichiometry of submerged aquatic plants: an experiment and meta-analysis

Human activity is currently changing our environment rapidly, with
predicted temperature increases of 1–5°C over the coming century and
increased nitrogen and phosphorus inputs in aquatic ecosystems. In the
shallow parts of these ecosystems, submerged aquatic plants enhance water
clarity by resource competition with phytoplankton, provide habitat, and
serve as a food source for other organisms. The carbon:nutrient
stoichiometry of submerged aquatic plants can be affected by changes in
both temperature and nutrient availability. We hypothesized that elevated
temperature leads to higher carbon:nutrient ratios through enhanced
nutrient-use efficiency, while nutrient addition leads to lower
carbon:nutrient ratios by the luxurious uptake of nutrients. We addressed
these hypotheses with an experimental and a meta-analytical approach. We
performed a full-factorial microcosm experiment with the freshwater plant
Elodea nuttallii grown at 10, 15, 20, and 25°C on sediment consisting of
pond soil/sand mixtures with 100, 50, 25, and 12.5% pond soil. To address
the effect of climatic warming and nutrient addition on the
carbon:nutrient stoichiometry of submerged freshwater and marine plants we
performed a meta-analysis on experimental studies that elevated
temperature and/or added nutrients (nitrogen and phosphorus). In the
microcosm experiment, C:N ratios of Elodea nuttallii decreased with
increasing temperature, and this effect was most pronounced at
intermediate nutrient availability. Furthermore, higher nutrient
availability led to decreased aboveground C:P ratios. In the
meta-analysis, nutrient addition led to a 25, 22, and 16% reduction in
aboveground C:N and C:P ratios and belowground C:N ratios, accompanied
with increased N content. No consistent effect of elevated temperature on
plant stoichiometry could be observed, as very few studies were found on
this topic and contrasting results were reported. We conclude that while
nutrient addition consistently leads to decreased carbon:nutrient ratios,
elevated temperature does not change submerged aquatic plant
carbon:nutrient stoichiometry in a consistent manner. This effect is
rather dependent on nutrient availability and may be species-specific. As
changes in the carbon:nutrient stoichiometry of submerged aquatic plants
can impact the transfer of energy to higher trophic levels, these results
suggest that eutrophication may enhance plant consumption and
decomposition, which could in turn have consequences for carbon
sequestration.