Lecture 18- Microbial Processes

Question 1

oligotrophic

Answer 1

• pelagic environment (water column) that has naturally very low plant nutrient concentrations
• vast subtropical gyres

Question 2

eutrophic

Answer 2

• pelagic environment that has naturally high plant nutrient concentrations
• coastal upwelling zones

Question 3

traditional food chain concept (1970’s)

Answer 3

• organisms are placed into trophic level based on autotroph verses heterotroph
• organism’s size

Question 4

traditional bacterial concentrations

Answer 4

were estimated from transmission light microscopy and culture-plate colony counts

Question 5

use of epifluorescent microscopy and fluorescent DNA stains

Answer 5

• became widespread between 1975 and 1985

- Dramatically increased estimates of bacterial abundance in the ocean

Question 6

new views of marine food webs recognize the importance of

Answer 6

high bacterial abundance and a large fraction of heterotrophic nanoflagellates (2-20-micron diameter cells) that are consumers of bacteria

Question 7

prochlorococcus

Answer 7

• new type of small autotroph bacteria found mostly in oligotrophic regions (1/3)
• found using a new technique called analytical flow cytometry

Question 8

Prochlorococcus abundance in the oligotrophic open-ocean is similar in magnitude to

Answer 8

the abundance of heterotrophic bacteria

Question 9

importance of prochlorococcus

Answer 9

• in low nutrient open-ocean environments, the growth advantage goes to smallest cells which are no prochlorococcus
• contributes more than 1/4 of the total ocean primary production

Question 10

what contributes the most to total ocean primary production?

Answer 10

heterotrophic bacteria

Question 11

what creates efficient biological carbon pump?

Answer 11

when the dominant phytoplankton cells are large, the dominant grazers are large and their large fecal materials easily sinks to the deep ocean taking organic carbon down with it

Question 12

What is the expected efficiency of the biological carbon pump for coastal upwelling zones?

Answer 12

the carbon pump is VERY EFFICIENT in coastal upwelling zones