Calcareous nannofossils, also known as coccolithophores, are unicellular algae that produce calcareous plates called coccoliths. They first appeared in the Late Triassic period and have been important for biostratigraphic dating. Coccolithophores inhabit the photic zone of oceans worldwide. They range in size from less than 20 micrometers to 60 micrometers. Coccoliths are composed of calcite or other minerals and aid in protecting the cell and regulating light intake. Due to their small size and fossil record, coccolithophores provide key information for determining the geological age of sediments.

1. Calcareous Nanno
Plankton
Prepared by :
Omar Abdelaziz
Ahmed Mohamady
Yomna Zaid
Aya Hassan
Asmaa Khaled
Supervised by :
Dr. Saida Taha

2.  INTRODUCTION
 RANGE & HISTORY OF STUDY
 BIOLOGY
 MORPHOLOGY
 ECOLOGY
 IMPORTANCE

3.  Unicellular, autotrophic marine algae called coccolithophores
 Plankton their size can range up to 60 μm, though they are
usually less than 20 μm and have calcareous tests
 Their established first occurrence was in Late Triassic
 They inhabit in the photic zone of the water column, poor in
nutrients and rich in oxygen. They are largely adapted to
normal salinity
 They live the open ocean, but some species have been found
both in coastal and fresh waters.
 Synonyms Calcareous nannofossils; Coccolithophores;
Coccoliths; Nannofossils; Nannoplankton
INTRODUCTION

4.  The Coccolithophores and Discoasters are examples of calcareous nannoplankton of
geological importance
 The coccolithophores (or coccolithophorids) belonging to the Haptophyta division
(unicellular alga)
 “Nannoplankton” and “coccolithophore” refer to the whole organism
 The test of the coccolithophores is known as a coccosphere and the tiny calcareous
plates constituting it are called coccoliths or Nannofossil” which are fossilized
 Coccolithophores and coccoliths refer to one taxonomic group
INTRODUCTION

5. Division (Phylum) HAPTOPHYTA Hibberd ex Cavalier-Smith, 1986Class PRYMNESIOPHYCEAE Hibberd, 1976Subclass
PRYMNESIOPHYCIDAE Cavalier-Smith, 1986
according to the rules of the International Code of Botanical Nomenclature (ICBN) with hierarchy:
Kingdom : Protista
 Division (Phylum) : Haptophyta
Class : Prymnesiophyceae
Subclass PRYMNESIOPHYCIDAE
Classification

6.  The coccolithophores appeared in the Late
Triassic, diversified in the Early Jurassic and
became a biostratigraphically significant group
of microfossil in the Cenozoic.
 The discoasters are larger in size and their
easily observable morphological features
make them a good microfossil for age
determination.
 Due to the minuteness of the coccoliths, the
identification of taxa requires examination
under a high power optical microscope or, even
better, a scanning electron microscope.
Range of coccolithophores
 Due to their small size, good recovery and
short stratigraphic ranges, the calcareous
nannofossils have become a reliable tool for
the biostratigraphic dating of both Mesozoic
and Cenozoic sediments.

7. Geologic time Associated nannofossil evolutionary events and changes
Late Triassic First appearance of nannofossil is the fossil record; rare occurrences in low paleolatitude
sites.
Triassic-Jurassic boundary Major extinction; almost all the Triassic species except the coccolith species, C. primulas,
went extinct.
Early Jurassic Major diversification with new Mesozoic families; holococcoliths appeared for the first
time; coccolith become the dominant group.
Jurassic-Cretaceous boundary Large turnover with extinctions and originations; 3 new nannolith families appeared (e.g.,
Nannoconus) steady diversity increase.
Mid-Cretaceous Broadly cosmopolitan nannofossil with well-knows high-fertility index species (e.g.,
B.constau, Z. erecnas neofiar).
Late Cretaceous Acme in diversity (~ 150 species); widespread chalk and marl depositions; marked
endemism in the Campanian.
K-Pg boundary Nannofossil mass extinction event; ~ 90% of the species went exntict.
Paleogene Rapid diversification in the Late Paleocene with several new lineages; ~120 species in the
Eocene; diversity drop in the Oligocene.
Neogene and Quaternary Miocene recovery and diversifications in the Discoaster families; overall diversity loss and
size reduction in the Quaternary.

8. History of study
 Coccoliths were first examined and first recorded use of the term "coccoliths" by Cristian Gottfried Ehrenberg
(1795–1875) study of the chalk from the island of Rugen in the Baltic Sea who thought they were inorganic products.
 It was not until the second half of the 19th century when Wallich found coccoliths joined to form coccospheres that an
organic origin was suggested. Even after the publication of Sorby's 1861 paper, following which the organic origin of
coccoliths was generally accepted, Ehrenberg remained unconvinced.
 The term “nannoplankton” was coined by the German scientist H. Lohmann in 1902 for plankton.
 They were named, and identified as made by living organisms by Thomas Henry Huxley, who realized they were a
major part of the rock we call chalk .The story of how the tiny cell produces its coccosphere is told by Westbroek.
 The Deep Sea Drilling Project (DSDP) and the Ocean Drilling Program (ODP) brought the stratigraphic value
of calcareous nannofossils to the attention of industry as well as the scientific community.
 Today, due to the speed of preparation, calcareous nannofossils have become the preferred tool for quick accurate
stratigraphic age determination in post-Palaeozoic calcareous sequences.

9.  The cell of the coccolithophore is of a spherical or
oval shape.
 The coccoliths are formed inside protoplasm, and then
extruded to the cell surface via a process.
 The functions of coccoliths include:
1. Protection of cell against damage and predation.
2. Regulation of light allowed into the cell.
3. Flotation by adopting a suitable shape (elongate
coccosphere, for example, contribute to
buoyancy).
Biology of the Coccolithophores

10.  The chloroplasts contain the chlorophyll for
photosynthesis.
 The chloroplast and nucleus serve as sites of photosynthesis
and genetic material.
 The mitochondria is associated with energy storage.
 The Golgi body is a stack of interlinked vesicles which serves
various biosynthesis functions and, in coccolithophores, is
modified as the site of coccolith formation.
Biology of the Coccolithophores

11. Biology of the Coccolithophores
 Most haptophytes, possess two flagella of equal
length and a third whiplike, coiled structure called
the “haptonema.”
 In a living coccolithophore, , two phases of life cycle
are recognized. The motile phase and the non-motile
phase.
 Reproduction in coccolithophores is predominantly
asexual and occurs via binary fission and have a
sexual life cycle

12. Morphology of coccolithophores
 There are two types of coccoliths
I. Holococcoliths : are made of
numerous minute crystallites, all
rhombohedral or hexagonal crystals
of similar shape and size. Coccolithus
pelagicus secreted in the motile
phase
II. Heterococcoliths : crystallites in
heterococcoliths are of variable
shape and size , they are more rigid
than the holoccoliths, The
heterococcoliths are built of plates,
rods and grains. Coccolithus
pelagicus secreted in the non-motile
phase of its life cycle. Held together
by an organic matrix.

13. Morphology of coccolithophores
 Mineralogically, the coccoliths are normally calcite
and sometimes aragonite or vaterite.
 The classification of coccolithophorids is based on :
I. Coccolith morphology
II. The mode of arrangement of coccoliths on the cell
III. The shape of the cell.
 The nannofossil Discoaters
are of star or rosette shape. They became extinct near the
Pliocene—Quaternary boundary and, therefore. . They
secreted tabular calcite, unlike the rhombohedral or
hexagonal crystals of the coccoliths, Because of their
robust construction, discoasters are more resistant to
dissolution.

14.  Coccoliths are classified depending on shape. Common shapes include:
 Calyptrolith :
Basket-shaped with openings near the base.
 Caneolith :
Disc- or bowl-shaped.
 Ceratolith :
Horseshoe or wishbone shaped.
 Cribrilith :
Disc-shaped, with numerous perforations in the central area.
 Cyrtolith :
Convex disc shaped, may with a projecting central process.
 Discolith :
Ellipsoidal with a raised rim, in some cases the high rim forms a vase or cup-like structure.
Coccolith shape classification

15.  Helicolith :
A placolith with a spiral margin
 Lopadolith :
Basket or cup-shaped with a high rim, opening distally
 Pentalith :
Pentagonal shape composed of five four-sided crystals
 Placolith :
Rim composed of two plates stacked on top of one another
 Prismatolith :
Polygonal, may have perforations
 Rhabdolith
Asingle plate with a club-shaped central process
 Scapholith :
Rhombohedral, with parallel lines in center

16. Ecology
Distribution
nutration
salinity
Temperature

17. Ecology of coccolithophores
 The coccolithophorids mostly live in marine waters from the shelf to the open ocean, with some
occurring in fresh and brackish waters.
 their vertical distribution in the ocean is limited to the photic zone, which is the uppermost 200 m
of the water column.
 Both the modern and the fossil calcareous nannoplankton suggest their high diversity in low
latitudes and in tropical and subtropical latitudes.
 The highest abundance of coccolithophores within phytoplankton communities is in oligotrophic
environments
 Temperature is an important factor in the growth of coccoliths.
 Emiliania huxleyi tolerates a salinity range of 45–15 ‰

18. • They provide critical information and
data on geologic age (biostratigraphy).
• Have important applications in
petroleum geology
• Provide sedimentary facies of
petroleum source and reservoir rocks
that have been deposited since the
Late Triassic
Importance of coccolithophores

19. Thanks