Haptophytes and Diatoms

Question 1

how many species of haptophyta and diatoms are there

Answer 1

H = 300 species
D = 9000 species

Question 2

outline some characteristics of haptophyta

Answer 2

kingdom = chromista
primarily marine phytoplankton

Question 3

what is a haptonema

Answer 3

thread like structures which extends from the cell along with 2 flagella of equal length used to capture prey

Question 4

what are two important haptophyte species

Answer 4

1) pavlovophyceae = food for bivalves
2) isochyrysis = used in hair products for pigemnts

Question 5

outline some characteristics of haptophyte scales

Answer 5

composed of calcified organic material called coccoliths

Question 6

what are cocclithophorids

Answer 6

the happtophyte families which have coccoliths which are highly reflective

Question 7

what is E.hyxleyi

Answer 7

a species of phytoplankton which forms blooms which are then attacked and destroyed by viruses recycling inorganic caco3

Question 8

in haptophytes what is the plastid surrounded by

Answer 8

a chloroplast endoplasmic reticulumn continous with the nuclear envelope

Question 9

how are haptophytes ecologically significant

Answer 9

• significant components of food webs
• consumers, grazing on DOC and cyanobacteria
• transport organic C
• important for global carbon cycling

Question 10

what is DMS

Answer 10

a volitle sulphur compound which affects atmospheric chemistry and global climate
after UV degredation it forms cloud condesnsation nucli forming clouds

Question 11

what is polysaccharide mucilage

Answer 11

a foam which clogs fishing nets but adds organic carbon to water

Question 12

what does the colonial stage of the phaeocystis species of haptophyte contribute

Answer 12

dominated phyto plankton of marhinal ice contributing to 10% of atmospheric phytoplanton sulphur compounds

Question 13

outline some characteristics of diatoms

Answer 13

kingdom= chromista
have heterokont = different flagella
one is tinsel and one is whiplash

Question 14

when did diatoms first appear

Answer 14

250 million years ago

Question 15

outline the structure of a diatoms cell wall

Answer 15

cell wall - frustule in two overlapping parts
the frustule made of silica with miunte intricate depressions, pores and pathways which connetc with living protoplasm within to the outside enviro

Question 16

what are the two major types of diatom

Answer 16

1) pennate - has bilateral symmetry
2) centric - has radial symmetry = large SA:V so float easier

Question 17

outline some characteristics of the life history of a diatom

Answer 17

• form resting cells in unfavourable conditions which sink
• germinate when conditions improbe
• most abundant in spring and atutum

Question 18

outline the diatom plastid

Answer 18

conatins chlorophyll a and c masked by a pigment fucoxanthin

Question 19

what is the reserve storage material in diatoms

Answer 19

lipids
water soluable polysaccharide chrysolaminarin

Question 20

what are the diatom feeding mechanisms

Answer 20

most = autotrophic
some heterotrophic= usually pennate diatoms
some live simbiotically in large marine protozoa = formaminiferans

Question 21

what is the ecological significance of diatoms

Answer 21

• primary food source
• rich in carbs and fatty acids
• some produce a neurotozin causing amnesiac shellfish poisoning

Question 22

what is the importance of macroalgae

Answer 22

acts as a home and nursery grounds
important for biodiversity
bioindicators of chemical change

Question 23

how can macroalgae act as a cover

Answer 23

stabalise areas by decreasing wave action
minimise sand abrasion
act as camoflage for some species

Question 24

outline the position of some macroalgae in different zones of rocky shores

Answer 24

red = lower down shore as bad at dessication
greens = upper shore
browns = very common at depths

Question 25

what factors affect zonation

Answer 25

• high exposure the zonation spreads over greater height
• ability to survive desication
• survival of osmotic shock
• abrasion resistance
• felxibility and strength against wave action