Wildfire impacts on phytoplankton communities of three small lakes on the Boreal Plain, Alberta, Canada: a paleolimnological study

Quantification of sedimentary pigments with high performance liquid chromatography enabled the examination of changes in phytoplankton community indicators after wildfire in three lakes on the Boreal Plain with 50-year sediment chronologies. The response of phytoplankton indicators to wildfire was strongest in the shallow Lake B19, with post-fire increased concentrations of beta-carotene (all phytoplankton), cyanobacterial pigments (echinenone, canthaxanthin), and lutein (chlorophytes) (p < 0.05). In the relatively deep headwater Lake B3, the indicator for all phytoplankton was not different after fire (p = 0.3), but important changes occurred in the phytoplankton community for 4 years after fire. The concentrations of cyanobacterial (echinenone, myxoxanthophyll) and diatoms + chrysophytes (fucoxanthin) indicators were higher and lower (p < 0.05), respectively, after fire. The relatively deep and non-headwater Lake B4 was little impacted by fire. An increase in cyanobacterial biomass after fire is most likely to occur in shallow headwater lakes on the Boreal Plain.