Environmental factors influencing the quantitative distribution of microcystin and common potentially toxigenic cyanobacteria in U.S. lakes and reservoirs

Abstract

Many species of cyanobacteria are capable of producing toxins and causing nuisance blooms, however response to environmental conditions is likely taxon-specific. Environmental factors influencing cyanobacterial composition and toxin production in lakes have been examined in many studies; yet are often confined to individual water bodies, or to a small number of systems within the same region. Here, data from the 2012 USEPA National Lakes Assessment are used to examine relationships between biovolume of common potentially-toxigenic cyanobacteria (Aphanizomenon spp., Cylindrospermopsis spp., Dolichospermum spp., Microcystis spp. and Planktothrix spp.) and environmental variables across the entire conterminous United States, and results are compared across nine distinct ecoregions. Total phosphorus and water clarity were identified as the most influential environmental factors correlated with phytoplankton community composition. The Northern, Southern and Temperate Plains ecoregions displayed the highest biovolumes of potentially toxigenic taxa on average, as well as highest mean concentrations of microcystin. In those three ecoregions, samples with microcystin concentrations greater than 1 ppb were primarily dominated by Planktothrix spp. while in all other ecoregions Dolichospermum spp. was the dominant genus. Canonical Correlation Analysis revealed a strong association between high microcystin concentrations and high nutrient concentrations (total nitrogen and total phosphorus), and between high microcystin concentrations and low percentage of watershed forest cover. Results from this study indicate that the likely occurrence of potentially toxigenic taxa in lakes and reservoirs is predictable on a biogeographical basis, depending on morphological and water quality characteristics. Data from this study may be useful to regional managers attempting to prevent or mitigate nuisance cyanobacterial blooms.

Drivers and ecological consequences of dominance in periurban phytoplankton communities using networks approaches

“…Dominance was determined by a combination of (i) water column characteristics, that are related to the intensity of local anthropogenic pressures (TN and TN:TP) and meteorological conditions (water temperature and stratification), and (ii) the capacity of waterbodies to buffer these pressures (surface, depth) or the potential for immigration of taxa from other lakes including harmful algea (connection to the hydrological network). Our results support previous investigations showing that high N concentrations (Almanza et al, 2018;Beaver et al, 2018;Bonilla et al, 2012;Marion et al, 2017;Paerl and Otten, 2016;Persaud et al, 2015) and warmer waters (Dokulil and Teubner, 2000;Paerl and Huisman, 2008;Wagner and Adrian, 2009) favor the dominance of Cyanobacteria in phytoplankton communities at large scales. This is thought to be related to the particular ecological traits of these organisms (Mantzouki et al, 2016), such as higher increase in growth rates per unit of temperature compared with other groups (Carey et al, 2012), their ability to fix atmospheric N 2 , or to regulate their buoyancy in stratified water columns associated with warmer waters (Rinke et al, 2010).…”

“…dominance in phytoplankton communities are still relatively scarce (Almanza et al, 2018) or were mostly focused on Cyanobacteria (Beaver et al, 2018;Marion et al, 2017;O'Farrell et al, 2019) and sometimes on only one or two species (Bonilla et al, 2012;Marmen et al, 2016). Moreover, there is no comparison of the consequence of dominance by various organisms on the structure and functioning of phytoplankton communities.…”

“…Continental aquatic ecosystems are considered among the most vulnerable to the combined pressure of anthropogenic activities and climate change (Adrian et al, 2009). In the recent decades, these pressures have led to an increase in the frequency and intensity of phytoplankton blooms in lakes all around the world (Aguilera et al, 2017b;Almanza et al, 2018;Beaver et al, 2018;Dokulil and Teubner, 2000;Moura et al, 2018;Ndlela et al, 2016;Paerl and Huisman, 2008;Paerl and Otten, 2016). Phytoplankton blooms correspond to rapid increases of primary producer's biomass, often associated with the dominance of only a handful of taxa.…”

Trophic States Regulate Assembly Processes and Network Structures of Picophytoplankton Communities in Subtropical Coastal Ecosystems

“…As an important component in aquatic coastal ecosystems, marine picophytoplankton are vital contributors of primary production [2] and perform a range of ecological roles in carbon xation, nutrient cycling and regulating overall food-web dynamics [3]. Nevertheless, eutrophication of aquatic ecosystems has led to an increase in the frequency and intensity of picophytoplankton blooms worldwide, which generally represent the rst responders to environmental perturbation [4][5][6]. This is of particular concern in densely populated shores where the usage and impacts of human populations on coastal ecosystems are strongly interconnected.…”

Trophic states regulate assembly processes and network structures of small chromophytic phytoplankton communities in subtropical coastal ecosystem

“…xation, nutrient cycling and regulating overall food-web dynamics (Bolaños et al, 2020;Capblancq, 1990;Falkowski et al, 1998). Furthermore, SCP generally become an important indicator of ecological change in marine ecosystems responding to environmental perturbation (Almanza et al, 2019;Beaver et al, 2018;Monchamp et al, 2018).…”