foraminifera micro-paleontology micro fossil

foraminifera

1. Herodotus
(c. 484-425 BC)
FORAMINIFERA

2. Felix Dujurdin(French
biologist(1935)
Alcided'Orbigny(French
naturalist-19
th
century)
Produced first
classification
Classified them in to
protozoans

3. Cushman (USA-
20
th
century)
Developed the use of
foramsas biostratigraphic
tools

5. Prof. Robert
Speijer(KU
Leuven University
Belgium)

6. Dr JawadAfzal
Dr Suleman

7. Foraminifera
Marine protozoanslargely enclosed in a test or shell
which may be composed of secreted organic
material, calcitie, aragonitie, or siilicalor may be
composed of aggliutinatedparticles.
Test -single chambered (unilocular)
multichambered(multilocular)
Chambers connected by an opening called
foramen-plural foramina –The name
Foraminifera is derived from this

8. Outer layer-connected with
inside of the test by an
opening called aperture
Inner layer-
storehouse
and factory
of the cell
protected by
a test
Used for trapping and
engulfing food particles
Also used for locomotery
purposes in benthic forms
Opening that allows the passage of
food, excretory products and
reproductive cells
Living Foraminifera
Contain the
engulfed
food
Secrete
enzymes which
helps in
metabolism
Helps during cell division
Outer layer-
Inner layer-

9. Life cycle of Foraminifera
Two alternation of generations.
reproduce
sexually
reproduce a sexually
The complete cycle may take
more than two years depending
on their geographic habitat.
BUT WHY???
Takes longer in higher latitudes
than tropics.
Agamonttest-In smaller
benthic -megalospheric
microspheric

11. Test (shell)
Doest the test provide strength to
Foraminifera?
Biological, physical and chemical
stresses in sea water
Biological stresses: accidental ingestion by worms, fish, echinoderms etc.
Predators such as gastropods scaphopodsthat prey upon benthic
foraminifera.
Physical stresses include harmful radiation such as UV rays from the sun,
abrasion and water turbulence.
Chemical stress include changes in salinity, pH, CO2 and toxins in water
So the soft parts (cytoplasm) are protected within the test and the test
plays an important role to compete with these circumstances.

13. Test composition and wall structure
Tectin. Composed of organic material, thin, flexible and transparent.
Common in suborder Allogromiina.
Arenaceous/Agglutinated. Consists of foreign particles such as quartz, calcite
grains, mica etc bounded together with cement.
Common in suborder Textulriina.
Calcareous. Most common and abundant and further classified in to three
types.
Porecelaneous, microgranularand hyaline perforate.
Common in all remaining suborders
Porecelaneous. appear milky white in reflected light and amber in transmitted
light.
Composed high Mg calcite.
Hyaline perforate. Glassy in reflected light and grey to clear in transmitted
light. Common in most of the Mesozoic and cenozoicforaminifera.
Composition may be low or high Mg calcite.
Microgranular. Dark in reflected light and opaque in transmitted light.
Micrograinsmay packed randomly or normal to the sufaceof the test.
Common in suborder Fusulilina.

15. Morphology of Foraminifera Test (shell)

16. Proloculus
Periphery
Outer margin of the test
Initial chamber of the test

17. Aperture
Main opening to the exterior
Chamber
The basic unit of the test which consists of a
cavity and the enclosing wall
Suture
Line of contact between chambers

18. Chambers arrangement
Single
Chambered (unilocular)
Multi-
Chambered (multilocular)
Uniserial
Multichamberedarrangement in a single
linear series is a uniserialtest.
Biserial
triserial
Multichamberedarrangement in two fold
series is a biserialtest.
Multichamberedarrangement in three
fold series is a triserialtest.

19. Planispiral
If the test coils in a single plane, the
coiling is called planispiralcoiling.
If test coils in a spire, like a
snail, the coiling is called
trochospiralcoiling.
trochospiral
Whorl: Volutionin coil through 360°
dorsal or spiral side/viewUmbilical/Ventral view
in which all whorls and
chambers are visible.
which shows only large
chambers of the last whorl.

20. trochospiral
dorsal or spiral side/viewVentral view
A raised area in centre of a coil is
called umboand a depression is
called umbilicus.
umboumbilicus
evolute involute
If earlier chambers were enveloped
by later ones, it is called involutetest.
If chambers of previously whorls are
visible, it is called evolutetest.

21. Foraminiferal ecology
Smaller benthics
5000 living species known yet
Best environmental indicators and
are found tidal marshes to deep
trenches of the oceans

22. Factors controlling distribution of smaller benthics
Light
Photic zone <200m in tropical
water
Photic zone deeper in tropics than
in higher latitudes
Rich in algae and grasses which is a
best home for many foraminifera
Foraminifera with porecellaneous
imperforate are more successful in
this habitat. E.gquinqueloculina
and Millolinella

23. Food
Foraminifera-ominores; feed on small
bacteria, protozoansand invertebrates
They may be epifaunal(living on the
sediments) or infaunal(inside the
sediments)
Epifaunalforms of the photic zone-
feed on diatoms (a kind algae with
a golden brown pigment), e.g
Discorbis.
Some foraminifera are know to
culture photosymbiontse.g.
Elphidium

24. Some of them feed on
phytodetritusof water column e.g.
Bathysiphons
Parasitic forms.
Lagena
Infaunalforms or those living
below the photic zone which live
inside the sediments depend on
dead organic matter or eat
bacteria. e.gLenticulina
Lenticulina

25. Substrate
What can be a substrate for benthic
foraminifera??
Foraminifera with flat or concave lower
surface prefer hard substrates such rock,
sea grasses and algae. e.g. Cibicides
Rock, sea grasses algae, mud, sand etc
They normally have thin tests
Cassidula
Infaunalforms-found up to 200 m
below sediments surface but
common in first 10 m.
Epifaunal.. Elphidium

26. Lower energy substrate with silts
and mud-typical of midshelfto
bathyl slope… bacterial common
Nodosaria
high energy sands substrate-lower
population….
Most infaunalforms are thin
shelled and elongate

27. Salinity
Normal sea water salinity-35‰
High diversity
Brackish lagoonal water-low
diversity
Agglutinated forms in such
environments-
Hypersalineenvironments
(with salinity 40‰)
Miliolidae-imperforate tests e.g
Quinqueloculina
Also tectinousforms such as
Elphidium
imperforate tests probably
helps in protecting endoplasm
from stressful osmotic gradient
Textularia

28. Nutrients and oxygen
Nutrients such as phosphates and
nitrates exert considerable control
over the primary productivity.
Low rate of food supply such as deep
sea-low densities of foraminifera but
diversity may be high
Very high rates of food supply to the
surface
Low diversitiesBut why???????
Larger benthicsand planktons
which are photosymbiontsare
discouraged
Blooms of bacteria are formed
which reduce oxygen (anerobic
conditions formed)

29. Temperature
Species are adapted to a specific
range of temperature
How temperature changes??
Depth
In tropics the surface water of
ocean has higher temperatue
(about 28 degree celcius) than
lower layers. e.gaverage
temperature at abyssal plain is 4
degree centigrade)
Latitude
Temperature decreases from
equator to poles.

30. So we can use foraminifera to
measure palaeotemperatures
and palaeobathymetry
Diversity
Number of taxa in an assemblage
Normally an assemblage is
dominant by one species
Lower dominance-higher
diversity
Marginal marine habitats-lower
diversity
Normal marine and deep sea
have higher diversity
Normal marine habitats-food is
scarce and competition is high-
they grow larges tests-K-stratgies

31. In unstable environments such as
lagoons results in lower diversity
and greater abundance-r-
stratigies
r-stratgiesmature quickly
LBF culture endosymbiontic
unicellular algae such as diatoms,
dinoflagellates, rhodophytesor
chlorophytes.

32. Ecology of the larger benthic Foraminifera
Larger benthic Foraminifera live
largely in oligotrophicreef and
carbonate shoal environments
Low nutrients availability
Biologically generated carbonate
build-ups
Living LBF are mainly restricted to
low latitude area, in nutrient
deficient, warm, shallow water
seas, associated with reefs and
are important producers of
carbonate sediments

33. In general the presence of the LBF in the fossil indicate
warm environment whereas their absence indicates a
cooler environment
Minimum temperature tolerated
by LBF 18
o
C
Most of them live above 35 m
depth.
With in their test chambers they
have small chamberletswhich with
traslucentouter walls which allows
for more efficient culturing of the
symbionts
Endosymbiontsrelease
photosynthates, consumes
respiratory CO
2during
photosynthesis and produces CO
3
which allows high rates of CaCO
3
precipitation during test growth

34. LBF grow larger tests and are K-
strategies
K-strategists have relatively long
life spans, large sizes, delayed
reproduction and exhibit low
reproductive effort in maturity.

35. Ecology of the planktonicForaminifera
Depth and food
100 living planktonicforaminifera
Reproduction-surface layer
Towards the end of adult stage
they sink in to the water column
and each species sink in to layer
of specific temperature
Shallow water species-upper 50
m of the photic zone
Those living in oligotrophic
environments, feed on copepods,
and supplement their diet by
culturing symbionts

36. Intermediate water species-50-
100 m of the photic zone
Oligotrophicenvironments and
culture endosymbionts
Deeper water species-below 100
m of the photic zone
Deeper planktonicforms living
below the photic zone feed on
phytodetritus
Very deeper forms have to cope
with the CCD
The level in the water column
where the CaCO
3supply equal
the CaCO
3solution
The level in the water column
where the CaCO
3
CCD fluctuates and usually lies
between 3000-5000 m deep

37. Temperature and latitude