Is Phytoplankton Response to Dust Deposition Driven by Composition or Lake Biogeochemistry?

Document Type

Conference Paper

Publisher

Association for the Sciences of Limnology and Oceanography

Publication Date

6-1-2023

Keywords

phytoplankton, lake biogeochemistry, atmospheric mineral dust

Abstract

The transport of atmospheric mineral dust from arid regions and/or wildfires has recently increased in some regions of the planet due to land use activities and drought. These more frequent events in conjunction with increases in global temperatures have the potential to affect aquatic ecosystems in unpredictable ways. In this experiment we test how the expected effect of warming on metabolic balance and community composition can be altered by a pulse of dust deposition in two bodies of water in Western US. To address this question, we carried out temperature-manipulation experiments using algal communities from two freshwater ecosystems that differed in pH and alkalinity with the addition of two different dust sources: one rich in phosphorus and one rich in calcium. Our results show that atmospheric dust inputs increased the abundance of cyanobacteria in both ecosystems, regardless of the temperature and chemical properties of the dust. Both dust sources exerted a greater positive effect on primary production and respiration in the lake with lower pH, which was especially enhanced under warming conditions. We discuss the mechanisms that drive these responses based on the chemical properties of mineral dust and the biogeochemical properties of water bodies.

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