We report on exquisitely preserved specimens of freshwater siliceous algae belonging to the classes Synurophyceae (scaled chrysophytes) and Bacillariophyceae (diatoms) from middle Eocene lake sediments in Northern Canada. When considered in the context of closest extant relatives, these microfossils present unequivocal biogeographic and ecological affinities with warm-water ochrophyte assemblages. We have identified scales that are unambiguously assigned to Mallomonas bangladeshica, a chrysophyte now restricted to tropical lake ecosystems. The diatom genus Actinella is also well represented in these sediments, again with the most comparable extant congeners found in tropical to subtropical localities, particularly in the Southern Hemisphere. We surmise that fundamental biogeographic reorganizations among lacustrine algae took place during Eocene hothouse paleoclimates. In this light, future climate warming should be viewed as a potent vector for similar community shifts, with attendant limnological implications.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 24 • No. 3