Lake superior sedimentary diatom profiles from the Medieval Climate Anomaly and twentieth century suggest recent assembl
- PDF / 1,111,602 Bytes
- 13 Pages / 547.087 x 737.008 pts Page_size
- 87 Downloads / 126 Views
(0123456789().,-volV) ( 01234567 89().,-volV)
ORIGINAL PAPER
Lake superior sedimentary diatom profiles from the Medieval Climate Anomaly and twentieth century suggest recent assemblage changes reflect novel environmental conditions A. R. Kireta J. E. Saros
. V. L. S. Chraı¨bi . M. D. O’Beirne . J. P. Werne .
Received: 6 November 2019 / Accepted: 21 July 2020 Ó Springer Nature B.V. 2020
Abstract We examined diatom assemblages in a sediment core from Lake Superior (Canada/USA) that spans the interval * 500–1350 CE and includes the Medieval Climate Anomaly (MCA), 950–1250 CE. We sought to determine whether diatom assemblages responded to climate change during that warm, dry period. From 500 to 1350 CE, diatom assemblages were dominated by Lindavia ocellata and Lindavia comensis and there were no significant changes in the diatom community during the MCA. In another core Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10933-020-00145-x) contains supplementary material, which is available to authorized users. A. R. Kireta (&) J. E. Saros Climate Change Institute and School of Biology and Ecology, University of Maine, Orono, ME 04469, USA e-mail: [email protected]
from Lake Superior, which spans the period * 1815–2010 CE, we documented significant changes in diatom assemblages, which began ca. 1940. We used recently established relationships between planktonic diatom taxa and climate and lake physicochemical variables from monitoring data, to assess the drivers of change in diatom assemblages during the past century. Results from the two cores suggest that multiple environmental drivers, including both climate change and human-mediated influences on nutrient cycling, led to shifts in recent diatom communities in Lake Superior. The lack of change in diatom assemblages during the MCA supports the conclusion that environmental changes in Lake J. P. Werne Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, PA 15260, USA
A. R. Kireta Swenson College of Science and Engineering, University of Minnesota Duluth, Duluth, MN 55812, USA V. L. S. Chraı¨bi Biological Sciences, Tarleton State University, Stephenville, TX 76402, USA M. D. O’Beirne Department of Earth Science, University of California, Santa Barbara, CA 93106, USA
123
J Paleolimnol
Superior during the past century are novel and were driven largely by human activities. Keywords Climate change Discostella Great lakes Lindavia MCA
Introduction Lake Superior (47.7°N, 87.5°W) is located in central North America and is bordered by the United States and Canada. The lake has an average depth of 147 m, a maximum depth of 406 m, and a surface area of 82,100 km2. Lake Superior is the largest lake in North America and is considered relatively pristine. Nevertheless, inferences from sedimentary diatom records suggest mild nutrient enrichment of the lake during the early twentieth century, following local European settlement in the nineteenth century (Stoermer et al. 1985; Chraı¨bi
Data Loading...
