Foraminifera and Climate

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Foraminifera and Climate
Sindia Sosdian Rutgers University
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What is the job of an oceanographer?
Geology
Biology
Climate
Chemistry
Physics
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What are Pale-oceanographers?
We study the history of the oceans in the
geologic past with regard to climate change!


Changes in the ocean can affect climate!
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What is climate?

• Climate is the average and variations of weather
  over long periods of time.

What is a good indicator of climate?
Before the instrumental record, how does one
measure temperature?
temperature
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Motivation
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FORAMinifera
live in the ocean
are small animals
the size of a grain of sand or smaller
tell us about the climate
are amoebas with shells
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Amoebas are.

• protozoa that moves by means of temporary
  projections called psuedopods, and is well-known
  as a representative unicellular organism.
• They have a shell like a clam that protects their
  body and helps them survive.

1-Food time (213) 2-Floating around
(315) 3-Hungry again. (849)
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In the ocean
Forams live in the surface or deep. When they
die their shell rains down or is deposited into
the sediment.
Surface ocean
Deep ocean
Mud/Sediment
Planktonics-Forams that live in the surface ocean
(popcorn, inflated) Benthics -Forams that
live in the deep ocean
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Benthic foraminifera
Some like to live in the dirt like worms
Some like to live on top of the dirt like
grasshoppers
epifauna
infauna
You can tell where they live by their body shape!
See 3-D example!
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Difference in shell shape
water
Epifauna
Abundance of epifauna/infauna
-Food supply -Oxygen levels -Current activity
Infauna
Oxygen and labile food
Epifauna
sediment
Low-oxygen tolerant and refractory food
Infauna
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Example (1)-Benthic foraminifera abundance
Species abundance
epifauna
infauna

-
Food

-
Oxygen
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Shell (Test) Shape

• Shells are built of hollow chambers separated by
  partitions with small opening that connects the
  chambers
• the shell may be made of organic compounds, sand
  grains and other particles cemented together, or
  crystalline calcite (CaCO3)

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Planktonics-float in the sea
O. universa
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Classification
unilocular -- a single chamber

• Based on characters of shell shape
• Wall composition and structure
• chamber shape and arrangement
• the shape and position of any apertures
• surface ornamentation
• other morphologic features of the shell

uniserial -- chambers added in a single linear
series
biserial -- chambers added in a double linear
series
tubular -- a simple hollow tube.
planispiral -- chambers added in a coil within a
single plane.
trochospiral -- chambers added in a coil that
forms a spire like a snail shell.
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Example (2) Classification of foraminifera
Word Bank
unilocular
uniserial
tubular
biserial
planispiral
trochospiral
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Playing with mud (shell collection)
modern
1000 years ago!!
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(No Transcript)
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Lets wash some mudand find some forams
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Take a look under the microscope
a
b
d
c
infaunal benthic
epifaunal benthic
planktonic
planktonic
Geological slide
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Just like trees
some like warm weather
It is cold down here!
some like cold weather
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Foraminifera and climate

• (1) Species abundance
• (2) Geochemical tracers in their shell

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Planktonic Species Abundance
abundance for each planktonic foraminifera
varies depending on temperature
Gulf stream waters
Warm central Atlantic
From WHOI-Oceanus
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Example (3)- Polar bear of Planktonic Foraminifera

• N. pachyderma
• -left coiling (lt8ºC)

-right coiling (gt 8ºC)
100
1
N. Pachyderma (left)
N. Pachy (left)/ N. Pachy (right)
0
0
0
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10
20
0
30
10
20
Sea surface temperature (ºC)
Sea surface temperature (ºC)
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Geochemical tracers
Ca2
Substitution of Mg (for Ca) in calcium carbonate
shells CaCO3 Mg2 -gt MgCO3 Ca2
Mg2
C
Mg/Ca0.38exp(0.09x T)
Mg/Ca0.867exp(0.11x T)
Benthic foraminifera
Planktonic foraminifera
Mg/Ca ratio in calcite shells is a function of
temperature!!
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Example (4)- Temperature change during the last
ice age
How cold was it for these sub-zero heroes during
the ice age?
Mg/Ca
Modern
Ice age (20,000 years ago)
  Mg/Ca modern Mg/Ca ice age T (ºC) modern T (ºC) ice age ? T (ºC)
Planktonic 2.5 1.9  
Benthic 1.2 0.8      
20.5
17.5
3
3
1
2
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Geochemical tracers
Incorporation of Mg in calcium carbonate
(calcite/aragonite) shells CaCO3 Mg2 -gt
MgCO3 Ca2
Mg/Ca0.38exp(0.09x T)
Mg/Ca0.867exp(0.11x T)
Benthic foraminifera
Planktonic foraminifera
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Ocean acidification and foraminifera

• The phenomenon is the result of simple chemistry.
  
• Carbon dioxide dissolves in seawater to form
  weak, carbonic acid.
• The problem is, acids dissolve limestone, or
  calcium carbonate, which is the main constituent
  of seashells.
• As the oceans become more acidic, it will become
  increasingly difficult for creatures' shells to
  form.

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Shell morphology and thickness
Plankton
pCO2
Go to the video!! 435 to 810 http//www.abc.net.
au/catalyst/stories/s2029333.htm
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Thank you !!!