title: Determining the probability of cyanobacterial blooms: the application of Bayesian networks in multiple lake systems.
abstract: A Bayesian network model was developed to assess the combined influence of nutrient conditions and climate on the occurrence of cyanobacterial blooms within lakes of diverse hydrology and nutrient supply. Physicochemical, biological, and meteorological observations were collated from 20 lakes located at different latitudes and characterized by a range of sizes and trophic states. Using these data, we built a Bayesian network to (1) analyze the sensitivity of cyanobacterial bloom development to different environmental factors and (2) determine the probability that cyanobacterial blooms would occur. Blooms were classified in three categories of hazard (low, moderate, and high) based on cell abundances. The most important factors determining cyanobacterial bloom occurrence were water temperature, nutrient availability, and the ratio of mixing depth to euphotic depth. The probability of cyanobacterial blooms was evaluated under different combinations of total phosphorus and water temperature. The Bayesian network was then applied to quantify the probability of blooms under a future climate warming scenario. The probability of the "high hazardous" category of cyanobacterial blooms increased 5% in response to either an increase in water temperature of 0.8°C (initial water temperature above 24°C) or an increase in total phosphorus from 0.01 mg/L to 0.02 mg/L. Mesotrophic lakes were particularly vulnerable to warming. Reducing nutrient concentrations counteracts the increased cyanobacterial risk associated with higher temperatures.
authors.forename: Anna
authors.initials: A
authors.lastname: Rigosi
authors.forename: Paul
authors.initials: P
authors.lastname: Hanson
authors.forename: David P
authors.initials: DP
authors.lastname: Hamilton
authors.forename: Matthew
authors.initials: M
authors.lastname: Hipsey
authors.forename: James A
authors.initials: JA
authors.lastname: Rusak
authors.forename: Julie
authors.initials: J
authors.lastname: Bois
authors.forename: Karin
authors.initials: K
authors.lastname: Sparber
authors.forename: Ingrid
authors.initials: I
authors.lastname: Chorus
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Watkinson
authors.forename: Boqiang
authors.initials: B
authors.lastname: Qin
authors.forename: Bomchul
authors.initials: B
authors.lastname: Kim
authors.forename: Justin D
authors.initials: JD
authors.lastname: Brookes
mesh_terms: D001499:Bayes Theorem; D000458:Cyanobacteria / Q000502:physiology*; D017753:Ecosystem; D057097:Harmful Algal Bloom / Q000502:physiology*; D060106:Lakes; D015233:Models, Statistical; D008962:Models, Theoretical