Week 31 Marine Biofilms

Question 1

What are Biofilms?

Answer 1

Aggregates of microorganisms in which cells are frequently embedded in a self-produced matrix of extra cellular polymeric substance that are adherent to each other and a surface

Question 2

What is a surface attached biofilm?

Answer 2

Only one layer is in direct contact with the substratum

Question 3

What is a floc?

Answer 3

A mobile biofilm that form in the absence of a substratum

Question 4

What are the four steps in the formation of biofilms?

Answer 4

1. Attachment
2. Colonisation
3. Development
4. Active dispersal

Question 5

Why do microbes form biofilms?

Answer 5

1. Means of microbial defence that increase survival

2. Allows cells to remain in a favourable niche

Question 6

Biofilms allow cell to cell communication, how does this increase their chance of survival?

Answer 6

More opportunities for nutrient and genetic exchange

Question 7

How can gradients exist within marine snow particles?

Answer 7

Microniches within large marine aggregates, centre may even turn anoxic if surrounding waters already suboxic

Question 8

What triggers the switch between planktonic to biofilm growth?

Answer 8

Cyclic di-guanosine monophosphate - regulates cell surface proteins required for attachment

Question 9

How are intra-cellular processes performed?

Answer 9

Quorum sensing and AHL

Question 10

Give 3 examples of where biofilms can aggregate?

Answer 10

1. On plastic
2. Marine snow
3. On zooplankton
4. On phytoplankton
5. In sponges

Question 11

Name two things that biofilms can induce?

Answer 11

1. Metal corrosion
2. Metabolise hydrocarbons
3. Change S-content

Question 12

Name two things bad biofilms can do?

Answer 12

1. Create frictional drag for pipes and vessels

2. Corrosive of concrete sewers and still pipes

Question 13

Name two ways to prevent biofilm formation and the cleaning of infected areas?

Answer 13

1. Use of specific enzymes
2. Application of quorum sensing inhibitors
3. Use of bacteriophages

Question 14

What is the problem with anthropogenic strategies to prevent biofilm formation?

Answer 14

The impact to the natural environment and aquaculture is still unknown

Question 15

Does the biodegradation of petroleum and hydrogen require aerobic or anaerobic degradation?

Answer 15

Both!

Question 16

What needs to occur for oil-oxidising bacteria to develop quickly? AN how much non-volatile hydrocarbons can they degrade?

Answer 16

1. Temperature needs to be warm enough

2. They can degrade 80% non-volatile hydrocarbon within a year

Question 17

Which hydrocarbons stay in teh environment much longer?

Answer 17

Branched chain and polycyclic hydrocarbons

Question 18

How do oil droplets form marine oil snow particles?

Answer 18

Forms slicks and droplets in seawater

Question 19

What facilitates hydrocarbon degradation of marine oil snow particles?

Answer 19

Larger surface area

Question 20

In the deep water horizon spill, what was initial degradation done by?

Answer 20

Bermanella sp.

Question 21

In the deep water horizon oil spill after initial degradation, what happened?

Answer 21

Microbes capable of degrading of polycyclic aromatic came such as rhodobacterales

Question 22

What can help promote hydrocarbon degradation on contaminated beaches?

Answer 22

Tidal pumping and oxic-anoxic cycling

Question 23

What two things are marine micro plastic biofilms shaped by?

Answer 23

Salinity and nutrient concentration

Question 24

Are microbes on plastics more likely to be pathogenic?

Answer 24

Not likely, there is a low pathogen abundance on plastic surface

Question 25

Do bacterial communities differ between those on plastic and those that are free living?

Answer 25

Biofilm communities on PVS seem more distinct

Question 26

Name three factors that affect plastic degradation?

Answer 26

1. Weathering
2. Photodegradation
3. Mechanical degradation
4. Fragmentation
5. Salt

Question 27

Which phyla do PET hydrolyses mainly occur>

Answer 27

Actinobacteria, Proteobacteria and bacterodetes