lec 22: a whole lot of pp

Question 1

what are some characteristics of cyanobacteria ()

Answer 1

• can fix N
• in relatively high P environ, N fixing genera are advantaged bc []
• can regulate buoyancy (positive buoyancy) which advantages cyanobacteria (shades out other ppton, floats to wherever nutrients are plentiful)
• resting state to survive unfavourable conditions
• super diverse in habitat spread

Question 2

what are some characteristics of chlorophytes

Answer 2

• minor contributor to total biomass (theres less of them floating around)
• thrive when N:P doesn’t favour cyanobacteria
• branched off from charophytes which were became our modern plants

Question 3

diatoms

Answer 3

• silica skeletons
• big + silica skeleton = sink to sediment and only floats when big mixing events occur
• adapted to low light (sitting in sediment)
• can have big resting states (years)

Question 4

chrysophytes + cryophytes

Answer 4

• flagellated (can move on their own, but relatively its a little bit)
• mixotrophic, but they’re small so they can only eat smaller bacteria
• important in oligotrophic + dystrophic systems (hella organic matter + shading)

Question 5

dinoflagellates

Answer 5

• flagellated
• mixotrophic
• larger than chryso/cryo –> can eat larger bacteria, but also big enough for fish to eat them
• can survive through cysts (survival resting strategy)

Question 6

as u move across the oligo-eu spectrum, how does pp domination change?