Week 31 Marine Biofilms Flashcards
What are Biofilms?
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
What is a surface attached biofilm?
Only one layer is in direct contact with the substratum
What is a floc?
A mobile biofilm that form in the absence of a substratum
What are the four steps in the formation of biofilms?
- Attachment
- Colonisation
- Development
- Active dispersal
Why do microbes form biofilms?
- Means of microbial defence that increase survival
2. Allows cells to remain in a favourable niche
Biofilms allow cell to cell communication, how does this increase their chance of survival?
More opportunities for nutrient and genetic exchange
How can gradients exist within marine snow particles?
Microniches within large marine aggregates, centre may even turn anoxic if surrounding waters already suboxic
What triggers the switch between planktonic to biofilm growth?
Cyclic di-guanosine monophosphate - regulates cell surface proteins required for attachment
How are intra-cellular processes performed?
Quorum sensing and AHL
Give 3 examples of where biofilms can aggregate?
- On plastic
- Marine snow
- On zooplankton
- On phytoplankton
- In sponges
Name two things that biofilms can induce?
- Metal corrosion
- Metabolise hydrocarbons
- Change S-content
Name two things bad biofilms can do?
- Create frictional drag for pipes and vessels
2. Corrosive of concrete sewers and still pipes
Name two ways to prevent biofilm formation and the cleaning of infected areas?
- Use of specific enzymes
- Application of quorum sensing inhibitors
- Use of bacteriophages
What is the problem with anthropogenic strategies to prevent biofilm formation?
The impact to the natural environment and aquaculture is still unknown
Does the biodegradation of petroleum and hydrogen require aerobic or anaerobic degradation?
Both!
What needs to occur for oil-oxidising bacteria to develop quickly? AN how much non-volatile hydrocarbons can they degrade?
- Temperature needs to be warm enough
2. They can degrade 80% non-volatile hydrocarbon within a year
Which hydrocarbons stay in teh environment much longer?
Branched chain and polycyclic hydrocarbons
How do oil droplets form marine oil snow particles?
Forms slicks and droplets in seawater
What facilitates hydrocarbon degradation of marine oil snow particles?
Larger surface area
In the deep water horizon spill, what was initial degradation done by?
Bermanella sp.
In the deep water horizon oil spill after initial degradation, what happened?
Microbes capable of degrading of polycyclic aromatic came such as rhodobacterales
What can help promote hydrocarbon degradation on contaminated beaches?
Tidal pumping and oxic-anoxic cycling
What two things are marine micro plastic biofilms shaped by?
Salinity and nutrient concentration
Are microbes on plastics more likely to be pathogenic?
Not likely, there is a low pathogen abundance on plastic surface
