Recipient Organization
STATE UNIV OF NEW YORK
(N/A)
SYRACUSE,NY 13210
Performing Department
Chemistry
Non Technical Summary
Functional, genetic and diversity data will beintegrated into a coupled biogeochemical ecosystem model of N cycling dynamics in Taihu. Ecosystemfunction, genetic markers, and taxonomic diversity information will help us develop, calibrate, and verifyan ecosystem model for Taihu, enabling a heuristic study-nflake function and forecasting lake response tofuture perturbations, especfally human nutrient impacts. Combining these types of data is needed as thenext step in aquatic. ecosystem medeling (Doney et al., 2004), but has rarely if ever. been accomplished.This proposal represents a novel integration of data into an ecosystem/biogeochemistry modelingframework, addressing the DIMENSIONS components as follows:. Function: Chemical transformations and pools of key inorganic and organic N-species implicated in CyanoHABs (ammonium, nitrate, organic-N- as urea) -( Gardner, PaerI) will provide data needed todevelop and calibrate and validate a predictive ecosystem model of C, N, P, and 0 2 cycling (Hellweger)and. be linked to the molecular information desoribed below (all Pis). The model will scale rate processmeasurements at specific times and locations to the ecosystem level across multiple years. Measures ofmicrocystin toxin production and its genetic I environmental control (Boyer, Paerl, Wilhelm), along withnutrient input controls on growth of the bloom-forming (and major source of microcystin) genusMicrocystis (Paerl, Wilhelm), will be coupled to the genetic work and provide direct linkage betweennutrient input dynamics, biology and toxin production in Taihu. The resulting model will relate closely toglobal toxic bloom proliferation and will focus on the environmental controls (Hellweger, Paerl).Phylogenetic and taxonomic diversity: Microbial communities1 will be analyzed by molecular andmorphological taxonomic tools (as appropriate). Combined 16S rDNA, 18s rDNA and functional geneswill identify the major community members (Wilhelm) using pyrosequencing (i.e. 454) complemented bySanger-style sequencing (as required). Quantitative PCR will enumerate community members andpotential (N transformation genes) within the background of other organisms (Wilhelm, Paerl) andseasonal changes in Microcystis (Paerl, Wilhelm, Boyer). Diversity data will be compared to predictionsof species composition from the ecosystem model (Hellweger ), and analyzed in context of the ecosystemfunction (above) (e.g., model-predicted productivity and cycling rates). ,Genetics: Activity of functional cellular components will be gauged by measuring expression of genesassociated with N transformations in situ (via reverse transcriptase (rt)PCR and rt-quantitative PCR). -(Wilhelm, Paerl). It will provide insight on the identity and potential effects of functional groups as wellas activity quantification. A suite of genes (plus any newly identified components) will be overlain on a·pathway model of functional N-transforming processes to determine "genetically-limiting" activities (i.e.,absent or reduced in the gene pool) or over-representation. An ongoing quantitative analysis of processesassociated with one of the major functional manifestations (production of microcystin; Boyer) will becoupled to this study matrix. Genetic data will provide another dataset for model calibration/validation;i.e., molecular data are related directly to model species (qPCR) and function (rt-qPCR).Awarded Start Date: 1/1/13Sponsor: University of Tennessee
Animal Health Component
(N/A)
Research Effort Categories
Basic
100%
Applied
(N/A)
Developmental
(N/A)
Goals / Objectives
The specific goals of thisintegrative study are to (1) develop an ecosystem model that resolves genetic, functional and taxonomicbiodiversity of the microbial community and its interaction with the N cycle, and (2) use the model tounderstand responses and feedbacks within this complex system driven by anthropogenic changes innutrient inputs.
Project Methods
Established biogeochemical, molecular biology and ecological techniques previously used primarily inisolation will be used in unison and coupled to a well-defined modeling effort. Stable isotope techniquesusing 15NH/ and 15N03- will measure the major forms and transformation rates·ofN compounds (Fig. 4)at the sediment-water interface (SWI) and in the water column (Mccarthy et al. 2007). Samples are·incubated at near in situ conditions to yield process rate data representative of natural and potential Ntransformation rates. The approaches quantify functional aspects ofN transformations for integration with .taxonomic and genetic information on responsible organisms.In parallel, our labs use state-of-the-art molecular techniques to address questions pertaining tobiologically driven nutrient cycles, with a focus on N and CyanoHABS occurring in many lakes,including development and application of quantitative molecular markers for organisms (Microcystis) andfunction (toxin production) that affect these resources (e.g.; Rinta-Kanto et al. 2009a). A statisticallyrelevant framework is designed to describe environmental function in relation to biological potential(genetics). The results will provide model-ready data that can be parameterized, integrated and interpreted-to help address . real world issues; - i.e., informing management of large lakes, including thoseexperiencing CyanoHABs.