Harmful Algal Blooms in Lake Ecosystems: Past, Present and Future

Human activities and climate change are affecting freshwater lakes. Eutrophication and warming often lead to algal growth and to changes in the lake phytoplankton and microbial community composition. One such change is the occurrence of Cyanobacterial blooms. Some species of cyanobacteria can produce harmful toxins (and hence the term harmful algal blooms (HABs) that affect both the water quality, as well as the resident pelagic and benthic communities.

 

While freshwater lakes worldwide have been experiencing regular HABs over the past century, we still do not have sufficient long-term data to increase our understanding of the mechanisms of how these blooms form, or the microbial community changes leading to the blooms. Lake sedimentary DNA can be helpful in revealing historical trends in eukaryotic algal and cyanobacterial communities. With enough long-term data, it would be possible to inform policy makers and environmental managers to better respond to the changes happening in lake water before the bloom occurs, and hence avoid or mitigate harmful ecological consequences.

 

Sampling lake sedimentary cores followed by extraction of sedimentary DNA (sedDNA) and sedimentary ancient DNA (sedaDNA) allows the investigation of present and past lake microbial profiles. We have access to sedimentary cores from several lakes around Oklahoma. We will extract both sedDNA and sedaDNA from the cores. The extracted DNA will be used as a template both for PCR targeting Cyanobacteria, as well as for shotgun sequencing. Following, community analysis, as well as read assembly and binning into metagenome-assembled genomes will provide a picture of the present (sedDNA) and a glimpse of the past (sedaDNA). These data will be combined with long term water chemistry data to inform machine learning models that will help predict the future of blooms and inform lake management for better prediction and response to blooms

 

Network Mentor: Dr. Noha Youssef