An assessment of plankton populations, toxic cyanobacteria, and potential impact of introduced marine alewife (Alosa pseudoharengus) in Pawtuckaway Lake, New Hampshire

A field study was conducted during the summer, 2005 to evaluate the lake water quality and planktonic communities in Pawtuckaway Lake, NH. Of special concern was the condition of the plankton populations since the lake had been subjected to introductions of adult sea-run alewife Overall water quality ranged from mesotrophic to eutrophic based on total phosphorus (8-31 !g L-1), chlorophyll a (max South, 5.0 !g L-1) and Secchi disk transparency (max North 5.1 m, min South 2.8 m). Of the three sites sampled, Fundy, North and South, Fundy (Zmax \u3c 2 m) did not stratify and had the highest concentrations of total phosphorus, followed by North and South sites, respectively. North and South sites stratified throughout the summer and developed anoxic hypolimnia, with the most severe oxygen deficit at the North site Potentially toxigenic cyanobacteria were detected at all three sites. Throughout the summer, the concentrations of the cyanotoxin microcystin in the lake were well above the average for NH lakes. Lakewater concentrations of microcystins exceeded WHO drinking water standards (1000 ng L-1) at the North site (1204.0 ng L-1) on July 21. The two dominant cyanobacteria were Anabaena spp.. and Microcystis aeruginosa. Oscillatoria (Planktothrix) were also present, but only rarely and therefore were probably were not responsible for most of the microcystins present in the lakewater

What makes a cyanobacterial bloom disappear? A review of the abiotic and biotic cyanobacterial bloom loss factors

Cyanobacterial blooms present substantial challenges to managers and threaten ecological and public health. Although the majority of cyanobacterial bloom research and management focuses on factors that control bloom initiation, duration, toxicity, and geographical extent, relatively little research focuses on the role of loss processes in blooms and how these processes are regulated. Here, we define a loss process in terms of population dynamics as any process that removes cells from a population, thereby decelerating or reducing the development and extent of blooms. We review abiotic (e.g., hydraulic flushing and oxidative stress/UV light) and biotic factors (e.g., allelopathic compounds, infections, grazing, and resting cells/programmed cell death) known to govern bloom loss. We found that the dominant loss processes depend on several system specific factors including cyanobacterial genera-specific traits, in situ physicochemical conditions, and the microbial, phytoplankton, and consumer community composition. We also address loss processes in the context of bloom management and discuss perspectives and challenges in predicting how a changing climate may directly and indirectly affect loss processes on blooms. A deeper understanding of bloom loss processes and their underlying mechanisms may help to mitigate the negative consequences of cyanobacterial blooms and improve current management strategies

Blooms also like it cold

Publication history: Accepted - 30 January 2023; Published - 17 February 2023.Cyanobacterial blooms have substantial direct and indirect negative impacts on freshwater ecosystems including releasing toxins, blocking light needed by other organisms, and depleting oxygen. There is growing concern over the potential for climate change to promote cyanobacterial blooms, as the positive effects of increasing lake surface temperature on cyanobacterial growth are well documented in the literature; however, there is increasing evidence that cyanobacterial blooms are also being initiated and persisting in relatively cold-water temperatures (< 15°C), including ice-covered conditions. In this work, we provide evidence of freshwater cold-water cyanobacterial blooms, review abiotic drivers and physiological adaptations leading to these blooms, offer a typology of these lesser-studied cold-water cyanobacterial blooms, and discuss their occurrence under changing climate conditions.Department of Agriculture, Environment and Rural Affairs, Northern Ireland ERDF/ESF Project Biomanipulation. Grant Number: CZ.02.1.01/0.0/0.0/16_025/0007417 MINECO. Grant Number: BES-2017-080558 US National Science Foundation (NSF). Grant Numbers: 1638554, 0639229, MSB 1137327, 1137353 Natural Sciences and Engineering Research Council of Canada. Grant Number: RGPIN-2018-06389 NOAA Office for Coastal Management. Grant Number: NA18NOS4200151 Projekt DEAL Spanish Agencia Estatal de Investigación. Grant Number: CTM2016-79741-R Swedish Research Council. Grant Numbers: 2020-01825, 2020-03222 Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning. Grant Number: 2020-01091 U.S. Geological Survey. Grant Number: G21AC1003

Blooms also like it cold

Abstract Cyanobacterial blooms have substantial direct and indirect negative impacts on freshwater ecosystems including releasing toxins, blocking light needed by other organisms, and depleting oxygen. There is growing concern over the potential for climate change to promote cyanobacterial blooms, as the positive effects of increasing lake surface temperature on cyanobacterial growth are well documented in the literature; however, there is increasing evidence that cyanobacterial blooms are also being initiated and persisting in relatively cold‐water temperatures (< 15°C), including ice‐covered conditions. In this work, we provide evidence of freshwater cold‐water cyanobacterial blooms, review abiotic drivers and physiological adaptations leading to these blooms, offer a typology of these lesser‐studied cold‐water cyanobacterial blooms, and discuss their occurrence under changing climate conditions