title: A bottom-up perspective on ecosystem change in Mesozoic oceans.
abstract: Mesozoic and Early Cenozoic marine animals across multiple phyla record secular trends in morphology, environmental distribution, and inferred behaviour that are parsimoniously explained in terms of increased selection pressure from durophagous predators. Another systemic change in Mesozoic marine ecosystems, less widely appreciated than the first, may help to explain the observed animal record. Fossils, biomarker molecules, and molecular clocks indicate a major shift in phytoplankton composition, as mixotrophic dinoflagellates, coccolithophorids and, later, diatoms radiated across shelves. Models originally developed to probe the ecology and biogeography of modern phytoplankton enable us to evaluate the ecosystem consequences of these phytoplankton radiations. In particular, our models suggest that the radiation of mixotrophic dinoflagellates and the subsequent diversification of marine diatoms would have accelerated the transfer of primary production upward into larger size classes and higher trophic levels. Thus, phytoplankton evolution provides a mechanism capable of facilitating the observed evolutionary shift in Mesozoic marine animals.
authors: Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA aknoll@oeb.harvard.edu.
authors: Andrew H
authors: 0000-0003-1308-8585
authors: AH
authors: Knoll
authors: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors: Michael J
authors: MJ
authors: Follows
mesh_terms: D000818:Animals; D005075:Biological Evolution; D017377:Diatoms / Q000145:classification; D004141:Dinoflagellida / Q000145:classification; D017753:Ecosystem; D005580:Fossils; D058087:Haptophyta / Q000145:classification; D009792:Oceans and Seas; D010839:Phytoplankton / Q000145:classification
keywords: ecosystem model; phytoplankton; predation