Topic 7: Haptophytes

Question 1

• In what type of environments are haptophytes most abundant?

Answer 1

Mostly marine
mainly low-nutrient tropical waters
Pelagic and near surface

Question 2

• Briefly describe the fossil record of haptophytes.

Answer 2

Best fossil record among algae
Calcite forms well preserved in sediments
Rise after mass extinction 250 MYA
The peak during late Cretaceous (63-95 MYA)
Decline and recovery 30-50 MYA

Question 3

• What is an haptonema and how is it different from a flagellum?

Answer 3

Filamentous appendage
Emerges from between flagellum
Either very short or very long
Cannot beat, bend and coils
Not for locomotion: used for feeding, sensory and attachment

Question 4

• Describe the functions of the haptonema.

Answer 4

Feeding: bending phagotrophic behaviour

Collision avoidance: sensory response to obstacles

Attachment to substrates

Question 5

• What means of locomotion do haptophytes have?

Answer 5

They usually have 2 flagella for movement

Or passive movement

Question 6

Name the different kinds of coccoliths that coccolith-bearing
haptophytes can develop and describe the difference between
them based on their development.

Answer 6

Holococcolith: organic scale from Golgi secreted to outside. Calcite is deposited as tiny crystals, not interlocked, held together by organics.

Heterococcolith: organic scales and and calcite deposition is internal (Golgi)
calcite crystals and coccoliths interlock

Question 7

• What are coccoliths made of and what are their functions?

Answer 7

CaCO3 is the calcite of coccoliths

Focus light into cells
protection from photodamage
Protection from pathogens
Protection against grazing
Buoyancy regulation, and nutrient acquisition
Protection from physical damage

Question 8

Why may coccolithophorids be more severely affected by ocean
acidification than other unicellular algae?

Answer 8

Ocean acidification makes it more difficult to form their calcium skeleton

This is dependent on photosynthesis and may affect their fitness for many reasons

Question 9

What colour are coccolithophorid blooms when seen from space?
Why?

Answer 9

Milky white or light blue
Reflectance of light from coccoliths

Question 10

Why did we talk about the Isle of Wight and the White Cliffs of
Dover (in England) during the presentation of this topic in lecture?

Answer 10

These cliffs represent the sediments left behind from coccolithophores from history

Question 11

What is (are) the equation (s) that represent the process of
calcification? What connection is there between calcification and
photosynthesis?

Answer 11

HCO3 + Ca –>CaCO3 + CO2 + H2O

CO2 + H2O –> CH2O + H2O + O2

Calcification is dependent on photosynthesis for ATP and NADPH

Products of calcification are used in the photosynthesis cycle

Question 12

• Describe the plastids and pigments in haptophytes.

Answer 12

One or two plastids that are butterfly shaped

Chl a and c2
Carotene
xanthophylls

The plastid has 4 membranes: 2nd endosymbiosis

Question 13

*What type of storage polysaccharide is found in haptophytes?

Answer 13

Use of chrysolaminaran contained in vacuoles

Question 14

• Draw the probable life cycle of Emiliania huxleyi.

Question 15

What type of cell/stage, in the life cycle, seems to have both
holoccocoliths and heterococcoliths?

Answer 15

The zygote is thought to have both holococcoliths and heterococcoliths

Question 16

Describe the ecological and climatic importance of haptophytes

Answer 16

They are major sources or blooms and creating large carbon sinks into the deep sea

They are major contributors to the DMS cycle and forming clouds

They form large blooms that are heavily grazed, major food source (high fatty acids)

Can form toxins that kill fish, tadpoles

Form major sediments in deep sea

Question 17

What is DMS and why is this important for climate? Briefly describe
the DMS cycle

Answer 17

volatile organic sulfur gas
become oxidzed, sulphate particles in atmosphere
Form acid rain and clouds

High UV –> more DMS released from phytoplankton –> more clouds –> cooling affect