Articles by Murray K. Gingras in JoVE
Determination of the Settling Rate of Clay/Cyanobacterial Floccules Tiffany Playter1, Kurt Konhauser1, George W. Owttrim2, Denise S. Whitford2, Tyler Warchola1, Cheryl Hodgson1,3, Aleksandra M. Mloszewska4, Bruce Sutherland1, J.-P. Zonneveld1, S. George Pemberton1, Murray K. Gingras1 1Department of Earth and Atmospheric Sciences, University of Alberta, 2Department of Biological Sciences, University of Alberta, 3Department of Earth Sciences, Simon Fraser University, 4Earth Sciences Department, University of Toronto The interaction and sedimentation of the clay and bacterial cells within the marine realm, observed in natural environments, can be best investigated in a controlled lab environment. Here, we describe a detailed protocol, which outlines a novel method for measuring the sedimentation rate of clay and cyanobacterial floccules.
Other articles by Murray K. Gingras on PubMed
Bilaterian Burrows and Grazing Behavior at >585 Million Years Ago Science (New York, N.Y.). | Pubmed ID: 22745427 Based on molecular clocks and biomarker studies, it is possible that bilaterian life emerged early in the Ediacaran, but at present, no fossils or trace fossils from this time have been reported. Here we report the discovery of the oldest bilaterian burrows in shallow-water glaciomarine sediments from the Tacuarí Formation, Uruguay. Uranium-lead dating of zircons in cross-cutting granite dykes constrains the age of these burrows to be at least 585 million years old. Their features indicate infaunal grazing activity by early eumetazoans. Active backfill within the burrow, an ability to wander upward and downward to exploit shallowly situated sedimentary laminae, and sinuous meandering suggest advanced behavioral adaptations. These findings unite the paleontological and molecular data pertaining to the evolution of bilaterians, and link bilaterian origins to the environmental changes that took place during the Neoproterozoic glaciations.
Response to Comment on "Bilaterian Burrows and Grazing Behavior at >585 Million Years Ago" Science (New York, N.Y.). | Pubmed ID: 23430639 Gaucher et al. suggest that their field observations and petrographic analysis of one thin section do not support an Ediacaran age for the trace fossils-bearing strata of the Tacuarí Formation. We have strengthened our conclusion of an Ediacaran age for the Tacuarí Formation based on reassessment of new and previously presented field and petrographic evidence.