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1

What is a CTD?

Oceanography instrument used to measure conductivity, temperature and pressure (D for depth)

2

Why is conductivity measured by a CTD?

It can be used to determine salinity

3

Why must huge amounts of water be sampled to examine organisms distribution?

Organisms are often distributed heterogeneously

4

In the study by Vargas et al. (2015), where was the greatest diversity found?

In the heterotrophic protist groups, especially those known to be parasites or symbiotic hosts

5

What are some key planktonic players in the ocean?

1. Viruses e.g. CroV
2. Bacteria e.g. Trichodesmium and Prochlorococcus
3. Archaea
4. Photosynthetic protists e.g. diatoms, dinoflagellates and coccolithophores
5. Heterotrophic protists e.g. Foraminifera, Radiolaria and Ciliates

6

How do viruses impact oceans?

-Parasitic, control many autotrophs
-Impact nitrogen cycling, particle size distributions, sinking rates of plankton
-Most abundant biological agent in the ocean

7

Why are bacteria so important in oceans?

They play a major role as decomposers, recycling nutrients and releasing dissolved organic matter (DOM)
Play a role in carbon flux

8

What is the process by which bacteria release nutrients back into water?

1. Organic particles sink
2. Bacterial decay regenerates nutrients
3. Occurs below the photic zone
4. Nutrients carried into deep water

9

What is a diazocyte?

A special nitrogen-fixing cell of the marine cyanobacteria Trichodesmium

10

What is the most abundant photosynthetic organism in the sea?

Prochlorococcus

11

Hotspots of Trichodesmium

Found in areas of warmer currents, where nutrients are low so not many other species could survive

12

What is Trichodesmium limited by? How do they get past it?

Phosphorus
They can use unusual sources of phosphorus - monophosphate esters and phosphonates

13

Example of symbiosis; puffer fish

Contain symbiotic bacteria that produce a deadly toxin called tetrodotoxin - puffer fish and detoxify the toxin

14

Archaea in oceans

-Can make up 20% of prokaryotes in particular regions of the oceans
-Many are extremophiles
-Common in water and sediments, important in coastal waters

15

Distribution of bacteria and archaea

Mainly in photic layer but still present in small amounts in deep oceans
Can be embedded in marine snow deep in oceans

16

How much of oceans biomass do microbes make up

More than 90%

17

Features and name of coccolithophores

Haptophyta
Photosynthetic protist
Calcium carbonate exoskeleton
Important photosynthesisers
Highly reflective so can cause changes in sea surface temperature

18

Diatom name and features

Eukaryotic plankton
Photosynthetic protist
Bacillariophyta
Cell extensions to aid flotation

19

Features and name of dinoflagellate

Photosynthetic protist
Dinophyta
Can bioluminesce
Up to 2 flagella for motility if waters are nutrient depleted

20

Features of Foraminifera

Single called heterotroph
Planktonic and benthic
Occur in animal guts, plankton, sediments and seaweed

21

Feature of Radiolaria

Shells form siliceous sediment on sea floor when they die

22

Ocean virus example

CroV attacks flagellate heterotroph Cafeteria roenbergensis

23

Features of ciliates

Many benthic but may inhabit guts or sea urchins
Some are planktonic
Important in the microbial loop

24

What work by Rumbo et al. (2000) sparks debate about symbiosis

The sea slug eats green algae and breaks down most of the algae but retains the chloroplasts to use for photosynthesis - is this symbiosis or just use of organelles?