Summer is a Research Geologist in the Geology, Minerals, Energy, and Geophysics Science Center. She received a PhD in Oceanography from Oregon State University in 2014. Since joining the USGS in 2016, she has been developing high-resolution paleoceanographic records from the North Pacific to better understand past climate dynamics in this region and interactions with the global climate system.
Summer Praetorius is a paleoceanographer who uses foraminiferal micropaleontology and other geochemical proxies to reconstruct changes in ocean properties in the past (circulation, temperature, and salinity). At the USGS, her work has focused largely on oceanographic changes in the North Pacific from the last Ice Age through the Holocene period. Her research interests include the dynamics of abrupt climate change, the history and climate impacts of the Missoula Floods, interactions between volcanism and climate in the past, ocean hypoxia, and coastal archaeological shell middens as paleoceanographic archives.
Professional Experience
2016 - present, US Geological Survey, Menlo Park, CA
2015-2016, Postdoctoral Research Fellow, Carnegie Institution for Science, Stanford, CA
2009-2012, National Science Foundation Graduate Research Fellow, Oregon State University, OR
2005-2008, Research Assistant, Woods Hole Oceanographic Institution, Woods Hole, MA
Education and Certifications
Ph.D., Oceanography, Oregon State University, 2014
B.A., Geology, Portland State University, 2005
B.A., Anthropology, Portland State University, 2005
Science and Products
Pacific Ocean Patterns, Processes, and Productivity (POP3): Impacts of ancient warming on marine ecosystems and western North America
Data release for Ice and ocean constraints on early human migrations into North America along the Pacific coast
Ice and ocean constraints on early human migrations into North America along the Pacific Coast
Past abrupt changes, tipping points and cascading impacts in the Earth system
Phasing of millennial-scale climate variability in the Pacific and Atlantic Oceans
Sea surface temperature across the Subarctic North Pacific and marginal seas through the past 20,000 years: A paleoceanographic synthesis
The role of Northeast Pacific meltwater events in deglacial climate change
Flushing of the deep Pacific Ocean and the deglacial rise of atmospheric CO2 concentrations
Global and Arctic climate sensitivity enhanced by changes in North Pacific heat flux
Science and Products
- Science
Pacific Ocean Patterns, Processes, and Productivity (POP3): Impacts of ancient warming on marine ecosystems and western North America
Projections for AD 2100 suggest warming of +1-4°C in the North Pacific Ocean, which will result in widespread transformations throughout the marine environment and western North America. Many of these changes are beyond the predictive capabilities of current climate models. To better address this future uncertainty, our team is developing a geological framework using past warm intervals as... - Data
Data release for Ice and ocean constraints on early human migrations into North America along the Pacific coast
Founding populations of the first Americans likely occupied parts of Beringia during the Last Glacial Maximum (LGM) (1). The timing, pathways, and modes of their southward transit remain unknown, but blockage of the interior route by North American ice sheets between ~26-14 cal kyr BP (ka) favors a coastal route during this period. Using models and paleoceanographic data from the North Pacific, we - Publications
Ice and ocean constraints on early human migrations into North America along the Pacific Coast
Founding populations of the first Americans likely occupied parts of Beringia during the Last Glacial Maximum (LGM). The timing, pathways, and modes of their southward transit remain unknown, but blockage of the interior route by North American ice sheets between ~26 and 14 cal kyr BP (ka) favors a coastal route during this period. Using models and paleoceanographic data from the North Pacific, weAuthorsSummer K. Praetorius, Jay R. Alder, Alan Condron, Alan Mix, Maureen Walczak, Beth Elaine Caissie, Jon ErlandsonPast abrupt changes, tipping points and cascading impacts in the Earth system
The geological record shows that abrupt changes in the Earth system can occur on timescales short enough to challenge the capacity of human societies to adapt to environmental pressures. In many cases, abrupt changes arise from slow changes in one component of the Earth system that eventually pass a critical threshold, or tipping point, after which impacts cascade through coupled climate–ecologicaAuthorsV. Brovkin, Edward J. Brook, J. Williams, S. Bathiany, T. Lenton, M. Barton, R. DeConto, J. Donges, A. Ganopolski, J. McManus, Summer K. Praetorius, A. de Vernal, A. Abe-Ouchi, H. Cheng, M Claussen, M. Crucifix, Virginia Iglesias, Darrell S. Kaufman, T. Kleinen, Fabrice Lambert, Sander van der Leeuw, Hannah Liddy, Marie-France Loutre, David McGee, Kira Rehfeld, Rachael H. Rhodes, Alistair W.R. Seddon, Lilian Vanderveken, Zicheng YuPhasing of millennial-scale climate variability in the Pacific and Atlantic Oceans
New radiocarbon and sedimentological results from the Gulf of Alaska document recurrent millennial-scale episodes of reorganized Pacific Ocean ventilation synchronous with rapid Cordilleran Ice Sheet discharge, indicating close coupling of ice-ocean dynamics spanning the past 42,000 years. Ventilation of the intermediate-depth North Pacific tracks strength of the Asian monsoon, supporting a role fAuthorsMaureen Walczak, Alan Mix, Ellen Cowan, Stewart Fallon, Keith Fitfield, Jay R. Alder, Jianghui Du, Brian Haley, Tim Hobern, June Padman, Summer K. Praetorius, Andreas Schmittner, Joseph Stoner, Sarah ZellersSea surface temperature across the Subarctic North Pacific and marginal seas through the past 20,000 years: A paleoceanographic synthesis
Deglacial sea surface conditions in the subarctic North Pacific and marginal seas are the subject of increasing interest in paleoceanography. However, a cohesive picture of near-surface oceanography from which to compare inter and intra-regional variability through the last deglaciation is lacking. We present a synthesis of sea surface temperature covering the open North Pacific and its marginal sAuthorsCatherine V. Davis, Sarah Myhre, Curtis Deutsch, Beth Caissie, Summer K. Praetorius, Marisa Borreggine, Robert C. ThunellThe role of Northeast Pacific meltwater events in deglacial climate change
Columbia River megafloods occurred repeatedly during the last deglaciation, but the impacts of this fresh water on Pacific hydrography are largely unknown. To reconstruct changes in ocean circulation during this period, we used a numerical model to simulate the flow trajectory of Columbia River megafloods and compiled records of sea surface temperature, paleo-salinity, and deep-water radiocarbon fAuthorsSummer K. Praetorius, Alan Condron, Alan Mix, Maureen Walczak, Jennifer McKay, Jianghui DuFlushing of the deep Pacific Ocean and the deglacial rise of atmospheric CO2 concentrations
During the last deglaciation (19,000–9,000 years ago), atmospheric CO2increased by about 80 ppm. Understanding the mechanisms responsible for this change is a central theme of palaeoclimatology, relevant for predicting future CO2 transfers in a warming world. Deglacial CO2 rise hypothetically tapped an accumulated deep Pacific carbon reservoir, but the processes remain elusive as they are underconAuthorsJianghui Du, Brian Haley, Alan Mix, Maureen Walczak, Summer K. PraetoriusGlobal and Arctic climate sensitivity enhanced by changes in North Pacific heat flux
Arctic amplification is a consequence of surface albedo, cloud, and temperature feedbacks, as well as poleward oceanic and atmospheric heat transport. However, the relative impact of changes in sea surface temperature (SST) patterns and ocean heat flux sourced from different regions on Arctic temperatures are not well constrained. We modify ocean-to-atmosphere heat fluxes in the North Pacific andAuthorsSummer K. Praetorius, Maria A. Rugenstein, Geeta Persad, Ken Caldeira - News