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RE: Paleontology and Dinosaurology 101: What layperson MUST to know about?
> -----Original Message-----
> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu]
> On Behalf Of David Marjanovic
> Sent: Monday, February 07, 2011 8:13 AM
> To: DML
> Subject: Re: Paleontology and Dinosaurology 101: What
> layperson MUST to know about?
> "What does a layperson HAVE TO know about?"
> > * During the Jurassic and (especially) the Cretaceous, a major
> > transformation of marine life occurred. Green-algae phytoplankton
> > were displaced by red- and brown-algae (which continue to dominate
> > modern marine ecosystems).
> I thought this change from "green oceans" to "red oceans"
> happened at the P-Tr boundary mass extinction?
> BTW, there are no planktonic brown algae (Phaeophyta),
> they're all multicellular and benthic. However, some of their
> fellow chromists (eukaryotes with a red alga as an
> endosymbiont) are planktonic and brown, such as the
> pelagophytes that make brown tides today.
> Not literally brown planktonic chromists include the
> haptophytes, to which the coccolithophores belong. Chalk only
> forms in "red oceans"!
"Brown" was supposed to be shorthand for "heterokonts", to include the diatoms.
Technically not brown, of course.
And while there is a shift at the P/Tr, it is by no means complete. It is only
with the great diversification of coccolithophorids
and diatoms during the Jurassic and Cretaceous that the oceans really "redden":
Martin, R.E., A. Quigg, & V. Podkovyrov. 2008 Marine biodiversification in
response to evolving phytoplankton stoichiometry,
Palaeogeography, Palaeoclimatology, Palaeoecology 258:277-291 DOI:
Thomas R. Holtz, Jr.
Email: email@example.com Phone: 301-405-4084
Office: Centreville 1216
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
Faculty Director, Science & Global Change Program, College Park Scholars
Mailing Address: Thomas R. Holtz, Jr.
Department of Geology
Building 237, Room 1117
University of Maryland
College Park, MD 20742 USA