Climate-induced changes in lake ecosystem structure inferred from coupled neo- and paleoecological approaches

Ecology
By: , and 

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Abstract

Over the 20th century, surface water temperatures have increased in many lake ecosystems around the world, but long-term trends in the vertical thermal structure of lakes remain unclear, despite the strong control that thermal stratification exerts on the biological response of lakes to climate change. Here we used both neo- and paleoecological approaches to develop a fossil-based inference model for lake mixing depths and thereby refine understanding of lake thermal structure change. We focused on three common planktonic diatom taxa, the distributions of which previous research suggests might be affected by mixing depth. Comparative lake surveys and growth rate experiments revealed that these species respond to lake thermal structure when nitrogen is sufficient, with species optima ranging from shallower to deeper mixing depths. The diatom-based mixing depth model was applied to sedimentary diatom profiles extending back to 1750 AD in two lakes with moderate nitrate concentrations but differing climate settings. Thermal reconstructions were consistent with expected changes, with shallower mixing depths inferred for an alpine lake where treeline has advanced, and deeper mixing depths inferred for a boreal lake where wind strength has increased. The inference model developed here provides a new tool to expand and refine understanding of climate-induced changes in lake ecosystems.



Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Climate-induced changes in lake ecosystem structure inferred from coupled neo- and paleoecological approaches
Series title Ecology
DOI 10.1890/11-2218.1
Volume 93
Issue 10
Year Published 2015
Language English
Publisher Ecological Society of America
Publisher location Brooklyn, NY
Contributing office(s) Northern Rocky Mountain Science Center
Description 10 p.
First page 2155
Last page 2164
Online Only (Y/N) N
Additional Online Files (Y/N) N