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Biological Oceanography & Limnology > Phytoplankton > Flashcards

Phytoplankton Flashcards

1
Q

the first phytoplankton

A

coccoid cyanobacteria

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2
Q

2nd phytoplankton

A

evolved from the engulfing of a photosynthetic prokaryote by an aerobic eukaryote
From this, two groups evolved- the Green Algae and the Red Algae

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3
Q

Three groups arose from the primary endosymbiosis…what came from secondary endosymbiosis

A

Euglenoids by ingestion of a green alga by a protozoan

Heterokonts (brown algae, chrysophytes and diatoms)

Cryptomonads
Haptophytes (Prymnesiophytes)

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4
Q

Apicomplexans

A

These are protozoan parasites such as malaria

The Chlorarachniophytes are Amoebas that have green chloroplasts

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5
Q

Cyanobacterial Characteristics

A

Prokaryotes: no membrane bound organelles (no nucleus etc.)
Circular DNA, no histone protein
Pigments: Chl a, Beta Carotine, Zeaxanthin, phycobiliproteins (Prochlorophytes have a divinyl Chl a & Chl b)
Rubisco (C fixation) in carboxysomes
Lack flagella
Cyanophycin: aspartic acid & arginine (N storage)

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6
Q

Thylacoids

A

flattened membrane sacks with photosynthetic pigments present

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7
Q

Carboxysomes

A

sites of C fixation

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8
Q

Cyanophycin

A

granules are for N storage

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9
Q

Polyphosphate

A

granules are site of P storage

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10
Q

Phycobiliproteins

A

are accessory pigments (absorb light energy at wavelengths where chl a doesn’t absorb).

Water soluble pigments with a structure like bile

Together form a phycobilisome near to PS I & PSII pigments
Very high efficiency of energy transfer to Chl a

Open Chain tetrapyrroles. Phycoerythrin (PE), phycocyanin (PC), allophycocyanin

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11
Q

Other accessory pigments

A

Carotenoids

Beta carotene

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12
Q

Carotenes

A

consist of long chain hydrocarbons & absorb shorter wavelengths (~400-500 nm). They don’t contain oxygen

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13
Q

Xanthophylls

A

like Carotenes but they contain oxygen

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14
Q

Five Orders of Cyanobacteria

A

Chroococcales, Pleurocapsales, Oscillatoriales, Nostocales, Stigonematales:

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15
Q

Chroococcales

A

Unicellular or in aggregates

Cyanobacteria

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16
Q

Pleurocapsales

A

unicellular to complex aggregates

Cyanobacteria

Can bore into calcareous rock and grow endolithically. Acid producing bacteria grow with them and do boring. Divide by multiple (1 to 4)or binary fission (1to 2) or baeocytes (1 to many) in mother cell.
Only few marine species

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17
Q

Oscillatoriales

A

filamentous (undifferentiated cells), no heterocysts

Cyanobacteria

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18
Q

Nostocales

A

filamentous & with heterocysts

Cyanobacteria

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19
Q

Stigonematales

A

filamentous & true branching, with heterocysts

Cyanobacteria

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20
Q

Planktonic cyanobacterial N2 fixers

A

Richelia intracellularis in some diatoms-lives as symbiont
Trichodesmium (5 species) all colonies
Katagnymene- single trichomes (filaments) with mucus sheath
Unicellular cyanos ~ 3-5 um in dia (Crocosphaera & Cyanothece). Fix N2 at night

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21
Q

Stromatolites

A

cyanobacterial mats with layering of sand

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22
Q

——- is O2 sensitive

A

Nitrogenase

Heterocysts protect from O2

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23
Q

How is phaeophytin different from chlorophyll a?

A

is that chlorophyll is chlorophyll (green pigment) while pheophytin is (biochemistry) a chlorophyll from which the central magnesium atom has been removed.

24
Q

Major source of iron for ocean?

A

dust

25
Q

Pelagophyceae

A

Unicellular, brown tides, Grow so dense that they shade seagrasses, thus killing them.

26
Q

Prasinophytes (Micromonadophyceae)

A

Primitive green flagellates with Chl a & b
4-8 flagella
Covered with scales
Coastal waters & tidepools

27
Q

what is Convoluta?

A

flatworm lives in sand and has algal symbiont Prasinophyte in tissue

Forms green patches on sand and as tide comes in disappears into sediments
Worms rely on photosynthate
Older worms eat the algae from tail to head then die and releases eggs with alga

28
Q

Raphidophytes

A

Two flagella, chl a & c & fucoxanthan
Vertically migrates 10-15 m daily
Has cyst stage
Toxic to fish, especially caged ones. In ’72 Chatonella killed $500 mil of Yellow tail fish in Japan

29
Q

Chrysophyceae

A

“Golden Algae”

Very diverse group, related to Prymnesiophytes but with no haptonema
Pigments: Chl a & c, B Carotene, Fucoxanthan, Diadinoxanthan, Violaxanthan
Storage: Chrysolaminarin
Most freshwater, found in tide pools
Usually 2 unequal flagella or just one

statospore (of silicon) for hard times

30
Q

Cryptomonads

A 
Chl a & c, Phycocyanin & phycoerythrin
2 equal or unequal flagella
Storage: Starch
Thylacoids in pairs
Have a gullet lined with trichocysts
Very abundant in brackish water
31
Q

Dinoflagellates

A

Basically a protozoan that has acquired chloroplasts
Most are motile & unicellular
~ 7 μm-2 mm in size
Some are colorless and can be phagotrophic or (heterotrophs)
Some totally autotrophic
Some are mixotrophs (both auto and heterotrophic) and can both photosynthesize and consume other phytoplankton
Some are symbionts (in corals & other organisms)
Some are parasites

32
Q

dinoflagellates pigments?

A

Chl a & c, B Carotene, Peridinin (signature pigment), rarely fucoxanthan & diatoxanthan
About 2000 species (90% marine)
Thylacoids in stacks of 3
Chloroplasts enclosed by double unit membrane

33
Q

Three Orders of Dinoflagellates

A

Prorocentrales (2 cellulose plates)
Dinophysidales (2 large cellulose plates & 12 small plates)
Peridiniales (many plates but some are without plates “naked”)

34
Q

When do we call dinoflagellates “naked”?

A

if they do not have any cellulose plates

35
Q

what do dinoflagellates have to sting prey?

A

trichocysts

36
Q

complex life cycle of dinoflagellates

A

Swimmers are haploid vegetative cells
When conditions become unfavorable, gametes are formed and a hystrichospheroid cyst (diploid) forms, with resistant sporopollinin cell wall, and falls to sediments
When conditions favorable, it excysts, undergoes meiosis and new vegetative cells formed
Pellicle cysts can also be formed for short term survival.

37
Q

Why do dinoflagellates bioluminesce?

A

Reduces predation, Flashing dinos when copepods try to eat them attract a predator

38
Q

What are plates made of in dinoflagellates?

A

cellulose (armor)

39
Q

When bioluminescence brightest and what is the value of it?

A

new moon, reduces predation

40
Q

Why do dinoflagellates vertically migrate?

A
  • food
  • -Many dinoflagellates vertically migrate into the nitricline at night to take up NO3 and to upper euphotic zone in morning to photosynthesize in the daytime. Shown is dino vertical migration in mesocosm
41
Q

Margalef’s Mandala

A

and provides a route map through the variations of phytoplankton composition in time and space, and the causes of these variations.

42
Q

Diatoms (Bacillariophyceae)

A

Consist of ~ 12,000 species
Plankton or Periphyton (attached)
4-5 μm- >1 mm
Pigments: Chl a & c, B carotene, Fucoxanthan, Diadinoxanthin, Diatoxanthin
Consist of two orders, Centrales & Pennales
Chloroplast has thylacoids in groups of three
Storage product is chrysolaminarin (B 1-3 linked glucose units) and lipids (5-15% dry wt young-40-50% when old)

43
Q

Diatom Frustule made of

A

Silicon & Silicate & Silica

44
Q

Diatom Frustule

A

the hard and porous cell wall or external layer of diatoms

Nutrients are exchanged through holes in the frustule. Holes are called punctae in pennates, and in centrics there are sieve like structures (areolae)

Outer buffer zone of frustule has a structural carbohydrate layer plus lipids and an amino acid template with a high serine content
Pennates can move if attached to something. The raphe is the long slit down the middle of the frustule and is involved in movement. Centrics have no raphe.

45
Q

Two orders of diatoms

A

Centrales & Pennales

46
Q

tell me about the buoancy of diatoms…

A

frustule is heavy, regulate the ionic content of the cell sap in vacuole.

They replace heavy ions such as Ca & Mg with lighter ions such as Na or K. This replacement actually makes them buoyant.

Shape of the cell influences sinking velocity and elaboration of cell shape increases surface area ratio and this increases viscous drag as it sinks

47
Q

MacDonald Pfitzer Rule

A

When a diatom divides, each of the original halves become the epitheca. Thus half of the cells become progressively smaller

48
Q

how do diatoms get back to thier OG size?

A

original large size by production of auxospores. Auxospores produced after sexual recombination

49
Q

what are diatom blooms dependant on?

A

a supply of silicic acid, hence typically occur in coastal areas.

50
Q

where are diatoms going to be the most prevalent?

A

where there is lots of silicic acid…

coastal areas which receive riverine input

Upwelling regions also have high diatom abundance and silicic acid concentrations are higher in deep water which upwells

Antarctic waters of the Southern Ocean have high concentrations of silicic acid and diatoms

Sedemented as opal (a biogenic mineral)

51
Q

what are Resting spores (diatoms)?

A

When a bloom is over and nutrients are exhausted, diatoms form resistant resting spores. Spores allow a short term (months) survival in sediments

52
Q

How genetically diverse are diatoms

A

In 2 years Jane Gallager (J. Phycol 1980 vol 16:464) isolated 457 clones of Skeletonema costatum.
Clones isolated in winter were genetically distinct from summer ones
They were as different as two different species but morphologically they all were identical.
No single isolate is representative of all populations

53
Q

When and why do diatoms have sex?

A

in order to avoid becoming smaller and smaller (MacDonals Rule) they need to reproduce sextually

54
Q

What concentration of silicic acid starts to become limiting? (diatoms)

A

Diatoms dominate when silicic acid concentrations are above 2 uM

they have a hard time at lower concentrations

55
Q

How diatoms retard copepod egg production?

A

The diatoms synthesize aldehyde molecules which arrest mitosis in eggs.

56
Q

What are Silaffins

A

Silaffins are involved in the formation of the cell walls of diatoms

57
Q

Punctae & aerolae (diatoms)

A

Aerolae– A general term for a round or oval pore in the silica wall of a diatom

Punctae – the plural form

Biological Oceanography & Limnology (5 decks)

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