Ecology of Lake Erie – Wetlands and lake-wide planktonic communities: A synthesis
No abstract available.
Lake Erie↗
Geology topics
Anna G. Boegehold
Publications and source records attributed to Anna G. Boegehold.
Bloom forming cyanobacteria can adversely affect zebra and quagga mussel veligers
Quagga ( Dreissena rostriformis bugensis ) and zebra ( D. polymorpha ) mussels are broadcast spawners that produce planktonic, free swimming veligers, a life history strategy dissimilar to native North American freshwater bivalves. Dreissenid veligers require highly nutritious food to grow and survive, and thus may be susceptible to increased mortality rates during harsh environmental conditions like cyanobacteria blooms. However, the impact of cyanobacteria and one of the toxins they can produce (microcystin) has not been evaluated in dreissenid veligers. Therefore, we exposed dreissenid veligers to eleven distinct cultures (isolates) of cyanobacteria representing Anabaena, Aphanizomenon, Dolichospermum, Microcystis, and Planktothrix species and the cyanotoxin microcystin to determine the lethality of cyanobacteria on dreissenid veligers. Six-day laboratory bioassays were performed in microplates using dreissenid veligers collected from the Detroit River, Michigan, USA. Veligers were exposed to increasing concentrations of cyanobacteria and microcystin using the green algae Chlorella minutissima as a control. Based on dose response curves formulated from a Probit model, the LC 50 values for cyanobacteria used in this study range between 15.06 and 135.06 μg/L chlorophyll- a , with the LC 50 for microcystin-LR at 13.03 μg/L. Because LC 50 values were within ranges observed in natural waterbodies, it is possible that dreissenid recruitment may be suppressed when veliger abundances overlap with seasonal cyanobacteria blooms. Thus, the toxicity of cyanobacteria to dreissenid veligers may be useful to include in models forecasting dreissenid mussel abundance and spread.
Ecotoxicology and Environmental Safety↗
Cyanobacteria reduce motility of quagga mussel (Driessena rostriformis bugensis) sperm
The temporal expansion of harmful algal blooms, primarily associated with cyanobacteria, may impact aquatic organisms at vulnerable life history stages. Broadcast spawning species release gametes into the water column for external fertilization, directly exposing sperm to potential aquatic stressors. To determine if cyanobacteria can disrupt reproduction in freshwater broadcast spawners, we evaluated sub‐lethal effects of cyanobacteria exposure on quagga mussel ( Dreissena rostriformis bugensis ) sperm. In laboratory studies, sperm were collected after inducing mussels to spawn using serotonin and exposed to 11 cultures of cyanobacteria including Anabaena flos‐aquae , Aphanizomenon flos‐aquae , Dolichospermum lemmermanii , Gloeotrichia echinulata , five cultures of Microcystis aeruginosa, M. wesenbergii , and Planktothrix suspensa . Sperm motility, using endpoints of cumulative distance traveled and mean velocity was calculated for a minimum of 10 individual sperm using a novel optical biotracking assay method. The distance and velocity at which sperm travelled decreased when exposed to Aphanizomenon flos‐aquae and two M. aeruginosa cultures. Our findings indicate that cyanobacteria impede the motility of quagga mussel sperm, which can potentially result in reproductive impairments to mussels, and potentially other broadcast spawning species.
Environmental Toxicology and Chemistry↗
Cyanobacteria reduce quagga mussel (Dreissena rostriformis bugensis) spawning and fertilization success
Quagga mussels ( Dreissena rostriformis bugensis ) are highly fecund broadcast spawners invasive to freshwaters of North America and western Europe. We hypothesized that environmental cues from phytoplankton can trigger gamete release in quagga mussels. Nutritious algae may stimulate dreissenid spawning, but less palatable food, such as bloom-forming cyanobacteria, could be a hindrance. The objective of our study was to test whether exposure to cyanobacteria can inhibit quagga mussel spawning and fertilization. We assessed spawning in the presence of serotonin, a known spawning inducer, where adult quagga mussels placed in individual vials were exposed to 13 cyanobacteria cultures and purified algal toxin (microcystin-LR) with artificial lake water as the control. Fertilization success was evaluated by combining eggs with sperm in conjunction with cyanobacteria, and enumerating zygote formation marked by cellular cleavage. Several cyanobacterial strains reduced spawning and fertilization success, but microcystin-LR had no effect. Fertilization was more sensitive to cyanobacteria than gamete release. Only 1 culture, Aphanizomenon flos-aquae , inhibited spawning, whereas 6 cultures consisting of Anabaena flos-aquae , Dolichospermum lemmermanii , Gloeotrichia echinulata , Lyngbya wollei , and 2 Microcystis aeruginosa isolates reduced fertilization rates by up to 44%. The effects of cyanobacteria on reproduction in invasive freshwater mussels in the wild have not yet been identified. However, our laboratory studies show that concentrations of cyanobacteria that are possible during bloom conditions probably limit reproduction. Reproductive consequences on wild populations may become more prevalent as cyanobacteria blooms occur earlier in the year, making overlap between blooms and mussel spawning more common. Describing the mechanism by which cyanobacteria inhibit spawning and fertilization could reveal novel control methods to limit reproduction of this invasive species.
Freshwater Science↗