Interplay between r- and K-strategists leads to phytoplankton underyielding under pulsed resource supply
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Fluctuations in nutrient ratios over seasonal scales in aquatic ecosystems can result in overyielding, a condition arising when complementary life-history traits of coexisting phytoplankton species enables more complete use of resources. However, when nutrient concentrations fluctuate under short-period pulsed resource supply, the role of complementarity is less understood. We explore this using the framework of Resource Saturation Limitation Theory (r-strategists vs. K-strategists) to interpret findings from laboratory experiments. For these experiments, we isolated dominant species from a natural assemblage, stabilized to a state of coexistence in the laboratory and determined life-history traits for each species, important to categorize its competition strategy. Then, using monocultures we determined maximum biomass density under pulsed resource supply. These same conditions of resource supply were used with polycultures comprised of combinations of the isolated species. Our focal species were consistent of either r- or K-strategies and the biomass production achieved in monocultures depended on their efficiency to convert resources to biomass. For these species, the K-strategists were less efficient resource users. This affected biomass production in polycultures, which were characteristic of underyielding. In polycultures, K-strategists sequestered more resources than the r-strategists. This likely occurred because the intermittent periods of nutrient limitation that would have occurred just prior to the next nutrient supply pulse would have favored the K-strategists, leading to overall less efficient use of resources by the polyculture. This study provides evidence that fluctuation in resource concentrations resulting from pulsed resource supplies in aquatic ecosystems can result in phytoplankton assemblages’ underyielding.
KeywordsNutrient pulses Competition Species traits Resource saturation Nutrient limitation
The authors would like to thank Ulrich Sommer, Jason Matthiopoulos, Georg Pohnert and three anonymous reviewers for their essential comments on this research work.
Author contribution statement
DLR and SS originally formulated the idea. SS and ES designed the experiments. LAP performed the experiments. DBD, ES, LAP measured the species traits. SS, ES, GDK, LAP performed statistical analysis. ES, SS, PGD, DLR provided the ecological and mechanistic interpretation of experimental results. SS, ES, GDK, LAP wrote the manuscript and DLR provided editorial advice. LAP, ES, SS and DLR revised the manuscript.
- Cardinale BJ, Duffy JE, Gonzalez A, Hooper DU, Perrings C, Venail P, Narwani A, Mace GM, Tilman D, Wardle DA, Kinzig AP, Daily GC, Loreau M, Grace JB, Larigauderie A, Srivastava DS, Naeem S (2012) Biodiversity loss and its impact on humanity. Nature 486:59–67. https://doi.org/10.1038/nature11148 CrossRefPubMedGoogle Scholar
- Hector A, Schmid B, Beierkuhnlein C, Caldeira MC, Diemer M, Dimitrakopoulos PG, Finn JA, Freitas H, Giller PS, Good J, Harris R, Hogberg P, Huss-Danell K, Joshi J, Jumpponen A, Korner C, Leadley PW, Loreau M, Minns A, Mulder CPH, O’Donovan G, Otway SJ, Pereira JS, Prinz A, Read DJ, Scherer-Lorenzen M, Schulze ED, Siamantziouras ASD, Spehn EM, Terry AC, Troumbis AY, Woodward FI, Yachi S, Lawton JH (1999) Plant diversity and productivity experiments in European grasslands. Science 286:1123–1127. https://doi.org/10.1126/science.286.5442.1123 CrossRefPubMedGoogle Scholar
- Hector A, Hautier Y, Saner P, Wacker L, Bagchi R, Joshi J, Scherer-Lorenzen M, Spehn EM, Bazeley-White E, Weilenmann M, Caldeira MC, Dimitrakopoulos PG, Finn JA, Huss-Danell K, Jumpponen A, Mulder CPH, Palmborg C, Pereira JS, Siamantziouras ASD, Terry AC, Troumbis AY, Schmid B, Loreau M (2010) General stabilizing effects of plant diversity on grassland productivity through population asynchrony and overyielding. Ecology 91:2213–2220. https://doi.org/10.1890/09-1162.1 CrossRefPubMedGoogle Scholar
- Hillebrand H, Durselen CD, Kirschtel D, Pollingher U, Zohary T (1999) Biovolume calculation for pelagic and benthic microalgae. J Phycol 35:403–424. https://doi.org/10.1046/j.1529-8817.1999.3520403.x CrossRefGoogle Scholar
- Katechakis A, Stibor H, Sommer U, Hansen T (2002) Changes in the phytoplankton community and microbial food web of Blanes Bay (Catalan Sea, NW Mediterranean) under prolonged grazing pressure by doliolids (Tunicata), cladocerans or copepods (Crustacea). Mar Ecol Prog Ser 234:55–69. https://doi.org/10.3354/meps234055 CrossRefGoogle Scholar
- Kilham P, Kilham SS (1980) The evolutionary ecology of phytoplankton. In: Morris I (ed) The physiological ecology of phytoplankton. University California Press, Berkley, pp 571–597Google Scholar
- Moore CM, Mills MM, Arrigo KR, Berman-Frank I, Bopp L, Boyd PW, Galbraith ED, Geider RJ, Guieu C, Jaccard SL, Jickells TD, La Roche J, Lenton TM, Mahowald NM, Marañón E, Marinov I, Moore JK, Nakatsuka T, Oschlies A, Saito MA, Thingstad TF, Tsuda A, Ulloa O (2013) Processes and patterns of oceanic nutrient limitation. Nat Geosci 6:701–710. https://doi.org/10.1038/NGEO1765 CrossRefGoogle Scholar
- O’Connor MI, Gonzalez A, Byrnes JEK, Bradley J, Cardinale J, Duffy E, Gamfeldt L, Griffin JN, Hooper D, Hungate BA, Paquette A, Thompson PL, Dee LE, Dolan KL (2016) A general biodiversity—function relationship is mediated by trophic level. Oikos 000:001–014. https://doi.org/10.1111/oik.03652 Google Scholar
- Parsons TR, Maita Y, Lalli CM (1984) A manual of chemical and biological methods for seawater analysis. Pergamon Press, OxfordGoogle Scholar
- Tilman D (1982) Resource competition and community structure. Princeton University Press, Princeton, New JerseyGoogle Scholar
- Utermöhl H (1958) Zur vervollkommnung der quantitativen phytoplankton-methodik. Verh Int Ver Theor Angew Limnol 9:1–38Google Scholar