Smoke on the Water! The Influence Regional Wildfires on the Ecological Structure of Castle Lake (CA, USA)

SUDEEP CHANDRA; FACUNDO SCORDO; ERIN SUENAGA; SUZANNE J. KELSON; JOSHUA CULPEPPER; STEVEN SADRO; CARINA SEITZ; KEVIN C. ROSE; CRAIG E. WILLIAMSON; FLAVIA TROMBONI; SIMON R. POULSON; LUCIA SCAFF; JUAN E. FIORENZA; TIMOTHY J. CALDWELL

Berlin

Congreso; 36th Congress of the International Society of Limnology; 2022

International Society of Limnology ; IGB Leibniz-Institute of Freshwater Ecology and Inland Fisheries

Increasing in frequency in the last decades and predicted to increase in intensity in the future, wildfires can influence the airsheds and aquatic ecosystems far from their source of ignition.We quantify the influence of wildfire smoke on Castle Lake (CA, USA) to understand the impacts on the physical, chemical, productivity, and fishes. Comparing a year with heavy smoke generated from regional fires with previous years, we found a 31% reduction in incident light an 11% reduction in photosynthetically active radiation (PAR). Underwater ultra-violet light and PAR was reduced by 65 and 44%, respectively. Lake habitats (littoral-benthic and epilimnion) respond differently to changes in light from smoke; pelagic primary production increased with no change to littoral metabolism. Epilimnetic productivity of algae increased despite a decrease in heat content perhaps due to release from UV-B photoinhibition. Littoral-benthic productivity did not change, possibly reflecting adaptation to high-intensity UV-B light in these habitats. Deeper metalimnetic and profundal chlorophyll and productivity was significantly reduced. Surprisingly, zooplankton composition biomass, composition, and diel vertical migration patterns was not significantly different however trout were notably and uncommonly absent from the littoral-benthic habitat. Our study, while a single lake case study, indicates the varying but dynamic impacts of wildfire smoke on a lake ecosystem from the physical and chemical dynamics to the individual animal and ecosystem scale traits. We offer conceptual models to guide our understanding of wildfire smoke influences on aquatic ecosystems.