Getting the “right” parameter values for models of the pelagic microbial food web

The microbial part of the pelagic food web is believed to be a highly dynamic and tightly coupled network in which system behavior emerges from organism properties and interactions. A central goal in microbial ecology is a quantitative understanding of these interactions. A key aspect of these linkages is again the efficiency of food acquisition in the different groups of planktonic organisms. Here we estimate osmotrophic nutrient affinity for inorganic nitrogen and phagotrophic prey clearance values, using a parsimonious model of the microbial food web and modern Bayesian Markov chain Monte Carlo (MCMC) methods. The model is fitted to experimental data from five mesocosms filled with northern Baltic seawater containing an N‐limited summer community and perturbed with different nutrient additions. The MCMC method successfully found one common set of parameters that not only gave a good fit to perturbation responses in all five mesocosms, but also was in reasonable agreement, both with values derived theoretically from first principles and allometric relationships, and with affinity values for phosphate in the experimental literature. Key properties of the structure and functioning of the microbial plankton food web can thus be derived and understood from fundamental physical‐chemical laws governing affinity for nutrient uptake by osmotrophs, and size‐selective grazing by key functional groups of phagotrophs.

[1]  E. Berdalet,et al.  Ability of a "minimum" microbial food web model to reproduce response patterns observed in mesocosms manipulated with N and P, glucose, and Si , 2007 .

[2]  J. Seppälä,et al.  Beyond bulk properties: Responses of coastal summer plankton communities to nutrient enrichment in the northern Baltic Sea , 2003 .

[3]  L. Øvreås,et al.  Use of non‐limiting substrates to increase size; a generic strategy to simultaneously optimize uptake and minimize predation in pelagic osmotrophs? , 2005 .

[4]  Dag L. Aksnes,et al.  A theoretical model for nutrient uptake in phytoplankton , 1991 .

[5]  T. Thingstad,et al.  Control of phytoplankton growth in nutrient recycling ecosystems. Theory and terminology , 1990 .

[6]  T. Andersen,et al.  Pelagic food webs and eutrophication of coastal waters : Impact of grazers on algal communities , 1996 .

[7]  Victor Smetacek,et al.  Pelagic ecosystem structure: Heterotrophic compartments of the plankton and their relationship to plankton size fractions 1 , 1978 .

[8]  R. Lignell,et al.  THEORETICAL MODELS FOR THE CONTROL OF BACTERIAL GROWTH RATE, ABUNDANCE, DIVERSITY AND CARBON DEMAND , 1997 .

[9]  Thomas R. Anderson,et al.  Plankton functional type modelling : running before we can walk? , 2005 .

[10]  T. Frede,et al.  Theoretical models for the control of bacterial growth rate , abundance , diversity and carbon demand , 2022 .

[11]  D. Kirchman Microbial ecology of the oceans , 2008 .

[12]  Judith Meyer,et al.  Nitrogen-limited growth of marine phytoplankton—II. Uptake kinetics and their role in nutrient limited growth of phytoplankton , 1972 .

[13]  E. Sherr,et al.  Heterotrophic dinoflagellates: a significant component of microzooplankton biomass and major grazers of diatoms in the sea , 2007 .

[14]  P. Comba,et al.  Part I. Theory , 2007 .

[15]  James S. Clark,et al.  Why environmental scientists are becoming Bayesians , 2004 .

[16]  T. Fenchel The ecology of heterotrophic microflagellates , 1986 .

[17]  Manfred Ehrhardt,et al.  Methods of seawater analysis , 1999 .

[18]  Weitao Zhang,et al.  Bayesian calibration of mechanistic aquatic biogeochemical models and benefits for environmental management , 2008 .

[19]  A. Brix Bayesian Data Analysis, 2nd edn , 2005 .

[20]  John K Kruschke,et al.  Bayesian data analysis. , 2010, Wiley interdisciplinary reviews. Cognitive science.

[21]  K. Christoffersen,et al.  Measurements of chlorophyll-a from phytoplankton using ethanol as extraction solvent , 1987, Archiv für Hydrobiologie.

[22]  R. W. Sheldon,et al.  The Size Distribution of Particles in the OCEAN1 , 1972 .

[23]  H. Utermöhl Zur Vervollkommnung der quantitativen Phytoplankton-Methodik , 1958 .

[24]  G. Bratbak,et al.  Cell volume to cell carbon conversion factors for a bacterivorous Monas sp. enriched from seawater , 2006 .

[25]  H. Kuosa Protozoan grazing on pico- and nanaphytoplankton in the northern Baltic Sea: direct evidence from epifluorescence microscopy , 1990 .

[26]  M. Furnas In situ growth rates of marine phytoplankton: approaches to measurement, community and species growth rates , 1990 .

[27]  Stephen P. Brooks,et al.  Assessing Convergence of Markov Chain Monte Carlo Algorithms , 2007 .

[28]  T. Fenchel Ecology of heterotrophic microflagellates. I. Some important forms and their functional morphology , 1982 .

[29]  M. Veldhuis,et al.  Physiological responses of three species of marine pico-phytoplankton to ammonium, phosphate, iron and light limitation , 2005 .

[30]  J. Seppälä,et al.  Vertical niche separation of phytoplankton: large-scale mesocosm experiments , 2001 .

[31]  Judith Meyer,et al.  Nitrogen-limited growth of marine phytoplankton—I. changes in population characteristics with steady-state growth rate , 1972 .

[32]  D. Stoecker,et al.  An experimentally determined carbon : volume ratio for marine “oligotrichous” ciliates from estuarine and coastal waters , 1989 .

[33]  E. Saiz,et al.  Planktivorous feeding in calm and turbulent environments, with emphasis on copepods , 1995 .

[34]  E. Sherr,et al.  Activity of marine bacteria under incubated and in situ conditions , 1999 .

[35]  Why environmental scientists are becoming , 2022 .

[36]  K. Y. Bφrshiem Cell volume to carbon conversion factors for a bacterivorous Monas sp. enriched from seawatr. , 1987 .

[37]  Peter A. Jumars,et al.  Physical constraints on marine osmotrophy in an optimal foraging context , 1993 .

[38]  Sallie W. Chisholm,et al.  Emergent Biogeography of Microbial Communities in a Model Ocean , 2007, Science.

[39]  Per Juel Hansen,et al.  Zooplankton grazing and growth: Scaling within the 2–2,000‐µm body size range , 2000 .

[40]  T. Thingstad,et al.  Specific affinity for phosphate uptake and specific alkaline phosphatase activity as diagnostic tools for detecting phosphorus-limited phytoplankton and bacteria , 2006 .

[41]  Peter Franks,et al.  Planktonic ecosystem models: perplexing parameterizations and a failure to fail , 2009 .

[42]  Weitao Zhang,et al.  Predicting the Frequency of Water Quality Standard Violations Using Bayesian Calibration of Eutrophication Models , 2008 .

[43]  F. Rassoulzadegan,et al.  Trophic control of bacterial growth in microcosms containing a natural community from northwest Mediterranean surface waters , 1999 .

[44]  Marcello Vichi,et al.  A generalized model of pelagic biogeochemistry for the global ocean ecosystem. Part I: Theory , 2007 .

[45]  Heikki Haario,et al.  Bayesian modelling of algal mass occurrences - using adaptive MCMC methods with a lake water quality model , 2007, Environ. Model. Softw..

[46]  Shibu Yooseph,et al.  Genomic and functional adaptation in surface ocean planktonic prokaryotes , 2010, Nature.

[47]  Espen Strand,et al.  Stepwise building of plankton functional type (PFT) models: A feasible route to complex models? , 2010 .

[48]  G. Bødtker,et al.  Relationship between phosphate affinities and cell size and shape in various bacteria and phytoplankton , 2009 .

[49]  F. Rassoulzadegan,et al.  Conceptual models for the biogeochemical role of the photic zone microbial food web, with particular reference to the Mediterranean Sea , 1999 .

[50]  R. Lignell,et al.  Effects of inorganic nutrients, glucose and solar radiation on bacterial growth and exploitation of dissolved organic carbon and nitrogen in the northern Baltic Sea , 2008 .

[51]  K. Šimek,et al.  Maximum growth rates and possible life strategies of different bacterioplankton groups in relation to phosphorus availability in a freshwater reservoir. , 2006, Environmental microbiology.

[52]  T. Thingstad A theoretical approach to structuring mechanisms in the pelagic food web , 2004, Hydrobiologia.

[53]  Elena Litchman,et al.  Trait-Based Community Ecology of Phytoplankton , 2008 .

[54]  Heikki Haario,et al.  DRAM: Efficient adaptive MCMC , 2006, Stat. Comput..

[55]  A. C. Redfield The biological control of chemical factors in the environment. , 1960, Science progress.

[56]  P. Kuuppo Annual variation in the abundance and size of heterotrophic nanoflagellates on the SW coast of Finland, the Baltic sea , 1994 .

[57]  M. Heldal,et al.  Content of carbon, nitrogen, oxygen, sulfur and phosphorus in native aquatic and cultured bacteria , 1996 .

[58]  J. Fuhrman,et al.  Thymidine incorporation as a measure of heterotrophic bacterioplankton production in marine surface waters: Evaluation and field results , 1982 .