Don E. Canfield talks with
ScienceWatch.com and answers a few questions about
this month's New Hot Paper in the field of
Geosciences.
Article Title: Late-Neoproterozoic deep-ocean
oxygenation and the rise of animal life
Authors:
Canfield,
DE;Poulton, SW;Narbonne, GM
Journal: SCIENCE
Volume: 315
Issue: 5808
Page: 92-95
Year: JAN 5 2007
* Univ So Denmark, Nord Ctr Earth Evolut, Campusvej 55,
DK-5230 Odense M, Denmark.
* Univ So Denmark, Nord Ctr Earth Evolut, DK-5230 Odense M,
Denmark.
* Univ So Denmark, Inst Biol, DK-5230 Odense,
Denmark.
(addresses have been truncated)
Why do you think your paper is highly
cited?
It is always a pleasant surprise when one finds that their work is well
received by the scientific community. I think this article has been well
received because we provide the first demonstration of oxygen penetrating
into the deep waters of the late Precambrian oceans. Importantly, this
oxygenation is timed with the emergence of the Ediacaran fauna, some of
which may have been early stem-group animals. Therefore, our work supports
a causal relationship between the oxygenation of the deep ocean and the
evolution of animals.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
"This helps
to elucidate the pathways leading
to human evolution, and it helps to
define Man's place in the
biological world."
I would say this work is best described as a new discovery.
Would you summarize the significance of your paper in
layman's terms?
Fossil evidence suggests that animals probably evolved sometime around 600
million years ago, and large animals appear around 575 million years ago.
Animals have an absolute requirement for oxygen for their respiration, so
it has often been speculated that large macroscopic animals (those with the
largest oxygen requirement) evolved when oxygen rose to permissible levels,
which would be about 10% of those levels we have today. Our study supports
this scenario by showing that the first occurrence of large respiring
organisms, some of which are likely stem-group animals, emerged on the
Avalon Peninsula in Newfoundland in concordance with oxygenation of this
local environment.
How did you become involved in this research, and were
there any problems along the way?
The history of atmospheric oxygen and its bearing on animal evolution has
long been an interest of mine. This particular study evolved through
discussions with
Guy Narbonne at Queens University in Kingston,
Ontario, Canada, who is an expert in Ediacaran fauna, and who had
already worked extensively on the Avalon Peninsula in Newfoundland. The
study was actually pretty straightforward without any really significant
difficulties.
Where do you see your research leading in the
future?
We would like to better understand the nature of the evolution of ocean
chemistry, and in particular the history of oxygenation of the oceans. This
means undertaking an extensive study of numerous different late Precambrian
geological formations.
Do you foresee any social or political implications for
your research?
This work is definitely nonpolitical. From a societal perspective, I think
that this work, and other works like it, helps to shed significant light on
the history of biological evolution on Earth. This helps to elucidate the
pathways leading to human evolution, and it helps to define Man's place in
the biological world. These are issues of fundamental, cross-cultural human
curiosity.
Donald Eugene Canfield
Professor, University of Southern Denmark
Director of the Nordic Center for Earth Evolution (NordCEE)
Odense, Denmark Web
Keywords: late-neoproterozoic deep-ocean oxygenation,
precambrian oceans, ediacaran fauna, early stem-group animals, large
macroscopic animals, guy narbonne, avalon peninsula in newfoundland,
ocean chemistry, oxygenation, biological evolution.