PC:
Wikipedia,
Wilso 44691
–
Ow
wo k,
Public
Domai
About
70
millio
yea s
ago,
du i g
the
late
C etaceous
pe iod,
a
yea
lasted
oughly
372
days
athe
tha
365,
mea i g
each
day
was
a ou d
half
a
hou
sho te
tha
it
is
today.
The
esea ch
team
exami ed
the
g owth
laye s
of
a
si gle
fossilised
udist
bivalve,
To eites
sa chezi,
ecove ed
f om
the
Al-Haja
Mou tai s
i
Oma .
Usi g
lase -based
sampli g,
the
esea che s
cou ted
daily
g owth
i c eme ts
i
the
shell
with
fa
g eate
accu acy
tha
ea lie
mic oscope-based
methods,
calculati g
both
the
le gth
of
the
C etaceous
day
a d
the
dista ce
betwee
the
Ea th
a d
the
Moo
at
the
time.
Acco di g
to
the
study
published
i
Adva ci g
Ea th
a d
Space
Scie ces,
titled
‘Subdaily-Scale
Chemical
Va iability
i
a
To eites
Sa chezi
Rudist
Shell:
Implicatio s
fo
Rudist
Paleobiology
a d
the
C etaceous
Day-Night
Cycle’,
the
shell
also
p ese ved
evide ce
of
ocea
tempe atu es
seve al
deg ees
wa me
tha
today,
a d
of
a
likely
elatio ship
betwee
the
mollusc
a d
photosy thetic
symbio ts,
simila
to
those
i
mode
gia t
clams.
Lase
a alysis
eveals
372
daily
g owth
i gs
i
a cie t
shell
The
specime
a alysed
i
the
study
lived
fo
mo e
tha
i e
yea s
o
a
shallow
seabed
i
the
t opics,
i
a
a ea
that
is
ow
d y
la d
i
Oma .
Acco di g
to
the
Adva ci g
Ea th
a d
Space
Scie ces
p ess
elease,
the
mollusc
“g ew
fast,
layi g
dow
daily
g owth
i gs,”
which
the
esea che s
we e
able
to
ide tify
a d
cou t
usi g
lase
ablatio -i ductively
coupled
plasma-mass
spect omet y
(LA-ICP-MS).
This
method
focused
a
lase
o
shell
sectio s
oughly
10
mic omet es
wide,
about
the
diamete
of
a
ed
blood
cell,
to
measu e
t ace
eleme t
co ce t atio s
li ked
to
daily
a d
seaso al
g owth.
The
app oach
combi ed
“poi t-by-poi t
a alysis”
with
li e-sca i g
LA-ICP-MS
a d
stable
isotope
measu eme ts
take
f om
the
same
shell,
allowi g
chemical
va iatio
to
be
studied
o
both
seaso al
a d
daily
scales.
The
team
used
th ee
sepa ate
cou ti g
methods,
cycle-le gth
estimatio ,
visual
laye
cou ti g
u de
mic oscopy,
a d
chemical
laye
cou ti g
f om
the
t ace
eleme t
eco ds,
to
c oss-check
thei
esults.
These
combi ed
to
p oduce
a
composite
estimate
of
372
g owth
lami ae
pe
yea ,
which
the
autho s
i te p eted
as
ep ese ti g
372
daily
cycles
of
shell
depositio .
Image
AI
ge e ated
Ea th’s
days
we e
23
hou s
a d
31
mi utes
lo g
70
millio
yea s
ago
Dividi g
the
le gth
of
a
yea ,
which
has
emai ed
co sta t
ove
geological
time,
by
372
days
gave
a
Campa ia
day
le gth
of
a ou d
23
hou s
a d
31
mi utes.
Because
the
le gth
of
a
day
depe ds
o
how
fast
the
Ea th
spi s,
a d
this
spi
is
g adually
slowed
by
tidal
f ictio
f om
the
Moo ,
the
esea che s
also
used
the
day-le gth
figu e
to
estimate
the
Ea th-Moo
dista ce
du i g
the
late
C etaceous.
Applyi g
established
models
of
the
Ea th-Moo
system,
they
calculated
a
dista ce
of
app oximately
3.83
×
10⁸
met es,
a
esult
the
autho s
desc ibe
as
co siste t
with
existi g
models
of
how
the
Moo
has
bee
et eati g
f om
Ea th
ove
geological
time,
cu e tly
at
a
ate
of
about
3.82
ce timet es
pe
yea .
A cie t
shell
eveals
evide ce
of
photosymbiosis
i
To eites
The
study
also
fou d
that
daily
chemical
va iatio
i
the
shell
exceeded
both
seaso al
a d
tidal
va iatio ,
a
patte
the
esea che s
li ked
to
the
p ese ce
of
photosy thetic
symbio ts
livi g
withi
the
mollusc,
simila
to
the
elatio ship
see
i
mode
gia t
clams.
De
Wi te
said
the
shell
showed
“a
ve y
st o g
depe de ce
o
this
daily
cycle,”
which
the
team
took
as
evide ce
of
the
day- ight
light
cycle
bei g
eco ded
di ectly
i
the
shell’s
chemist y.This
fi di g
was
desc ibed
by
Pete
Skelto ,
a
udist
specialist
ot
i volved
i
the
study,
as
the
fi st
pape
to
p ovide
co vi ci g
evide ce
fo
photosymbiosis
i
To eites,
though
he
oted
the
co clusio
applies
specifically
to
this
ge us
athe
tha
to
udists
mo e
b oadly.
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