Heatwave-mediated decreases in phytoplankton quality negatively affect zooplankton productivity
Data files
Feb 02, 2024 version files 110.95 KB
Abstract
- Climate change is expected to increase the frequency of extreme temperature events. The effect of heatwaves on phytoplankton is of particular concern because they are a key source of C, N, P, and essential fatty acids to aquatic ecosystems. Laboratory studies have demonstrated that phytoplankton grown at warmer temperatures are a lower-quality food source, but how heatwaves affect phytoplankton quality at the community scale is currently unclear.
- Here we address this knowledge gap by growing natural assemblages of freshwater phytoplankton at ‘ambient’, ‘constant warming’, or ‘heatwave’ conditions. We next fed these phytoplankton communities to natural assemblages of zooplankton to test the prediction that zooplankton that consume heatwave-exposed phytoplankton will exhibit reductions in biomass.
- Our experiment demonstrated that zooplankton that consumed ‘heatwave’ phytoplankton attained lower community biomass than those fed ‘constant warming’ or ‘ambient’ phytoplankton. Additionally, despite receiving similar total heat input, phytoplankton exposed to ‘heatwave’ conditions contained lower C, N, P, and fatty acid concentrations compare to phytoplankton grown in ‘constant warming’ conditions.
- Correlations between zooplankton biomass and all measured phytoplankton traits revealed that decreases in zooplankton biomass were best explained by low quantities of C, N, and monounsaturated fatty acids in ‘heatwave’ phytoplankton.
- Our study demonstrates that the effects of heatwaves on phytoplankton quality are clearly distinct from those caused by constant warming temperatures, and that heatwave-mediated decreases in resource quality have immediate effects on consumer productivity.
README: Heatwave-mediated decreases in phytoplankton quality negatively affect zooplankton productivity
https://doi.org/10.5061/dryad.q83bk3jqc
Data file: Kim-et-al-func-ecol-heatwave-zoop-algae-data-dryad.csv
Associated figures from the manuscript: Figures 2-4, 5a, 6-8, S2a,b, S4-S7
Column Name descriptions:
- bucket - unit of replication
- sampling_event – phytoplankton were sampled three times (1, 2, 3). A subsample of zooplankton was counted and identified at each sampling event but other zooplankton traits were taken on sampling event 3. Phytoplankton phosphorus was sampled once (3).
- period - same as sampling_event except describes approximately when during the experiment the samples were taken
- treatment – three algal temperature treatments were used: Heatwave, Warm, and Ambient
- total.zoop – total number of zooplankton in the subsample
- zoop.dry.sample.weight.mg – total dry mass of all of the zooplankton in the bucket at the end of the experiment
- phyto.dry.mass.mg.per.mL – dry mass of the phytoplankton sub-sample
- zoop.shannon.diversity – zooplankton Shannon diversity (H’), calculated using the data in the data file “Kim-et-al-func-ecol-heatwave-zoop-taxonomy-data-dryad.csv”. Shannon diversity was calculated in R.
- phyto.C.ug.per.ml – phytoplankton carbon concentration; units are µg per mL algae
- phyto.N.ug.per.ml – phytoplankton nitrogen concentration; units are µg per mL algae
- phyto.P.ug.per.ml – phytoplankton phosphorus concentration; units are µg per mL algae
- zoop.SFA – zooplankton percent saturated fatty acids (see Methods for details)
- zoop.MUFA – zooplankton percent monounsaturated fatty acids (see Methods for details)
- zoop.PUFA – zooplankton percent polyunsaturated fatty acids (see Methods for details)
- zoop.n3 – zooplankton percent omega-3 fatty acids (see Methods for details)
- zoop.n6 – zooplankton percent omega-6 fatty acids (see Methods for details)
- zoop.n3.n6 – zooplankton ratio of omega-3 to omega-6 fatty acids (see Methods for details)
- pufa.ug.per.mg.algae - phytoplankton polyunsaturated fatty acid concentration; units are µg per mg algae
- mufa.ug.per.mg.algae - phytoplankton monounsaturated fatty acid concentration; units are µg per mg algae
- sfa.ug.per.mg.algae - phytoplankton saturated fatty acid concentration; units are µg per mg algae
- n6.ug.per.mg.algae - phytoplankton omega-6 fatty acid concentration; units are µg per mg algae
- n3.ug.per.mg.algae - phytoplankton omega-3 fatty acid concentration; units are µg per mg algae
- n3-n6-ug-ratio - phytoplankton ratio of omega-3 to omega-6 fatty acids
na - denotes no data either due to the prescribed sampling method or from losing the sample during processing
Data file: Kim-et-al-func-ecol-heatwave-algae-taxonomy-data-dryad.csv
Associated figures from the manuscript: Figure 5b, S3
Column Name descriptions:
- bucket – unit of replication
- sampling_event – phytoplankton were sampled three times (1, 2, 3).
- period – same as sampling_event except describes approximately when during the experiment the samples were taken
- treatment – three algal temperature treatments were used: Heatwave, Warm, and Ambient
- major_group – broad classification of phytoplankton used here
- taxon – scientific naming of the major_group classification
- unit_code – whether the phytoplankton grew as a filament, colony, or single cell
- units_counted cells.per.unit – how many units were counted in the sub-sample
- colony.size – grouping of colonies, filaments, or cells into size classes (see Methods for details)
- unit.size.together – joined classification of unit type and size class
- morpho.species.name – joined classification of the taxonomic group, unit type, and size class
- morpho.species.name.abbreviated – abbreviation of the morpho.species.name
- units.per.mL – extrapolation of number of units per mL
- cells.per.mL – extrapolation of number of cells per mL
Data file: Kim-et-al-func-ecol-heatwave-zoop-taxonomy-data-dryad.csv
Associated figure from the manuscript: Figure S2
Column Name descriptions:
- bucket – unit of replication
- sampling_event – phytoplankton were sampled three times (1, 2, 3).
- period – same as sampling_event except describes approximately when during the experiment the samples were taken
- treatment – three algal temperature treatments were used: Heatwave, Warm, and Ambient; zooplankton were then fed algae grown in one of these treatment types
- zooplankton.taxa – broad classification of zooplankton
- counts – number of individuals of each type that were counted in the subsample
Methods
The study was a laboratory experiment using wild-caught phytoplankton and zooplankton communities. All data were collected and analyzed by the authors except that phytoplankton were identified by Biologica Environmental Services in Victoria British Columbia, Canada. Phytoplankton taxonomy data were analyzed by the authors.