Project Title: Examination of bacterial content of sea water samples from selected sites in South East England Introduction Over the past few years coastal beaches across the UK has seen lavished with recognition for their cleanliness, by sections of the media and various organisarions. Majority of these beaches have been awarded the Blue flag award in recognition for meeting set criteria on various standard including cleanliness, water quality, environmental management and environmental education and information programme; an award ran by independent non-profit organisation Foundation for Environmental Education (FEE) and with similar programme ran by The marine conservation society (MCS). The general perception is that this beaches clean due to the reduce numbers of household litters presents, giving the impression that the litter level are the determinant of the cleanliness of the water.
This study intends to examine:
The bacteria population of samples obtained from several site across south east coast of England.
Identify species of Gram Negative (-) & (+) of each sample.
identify any faecal coliform bacteria which might suggest water contamination.
These indicator organisms are used for indication of water contaminant by human and other warm-blooded animals (APHA 1992). Several sample will be obtained from beach that are participant in some form of recognised sanitary programme and have meet set criteria by a recognised monitoring body. While several more sample will be obtained from location not participating in any such sanitary programmes. This will ensure an even sample distribution of bacterial population and data comparison.
Various bacteriological techniques will then be employed to help identify any present bacteria species.
Of the four samples; the bacteria population count would be lower in samples obtained from location awarded the “blue flag” award.
Material, Equipment and Method
Sterile water/ saline sol
R2A & R3A Agar
Crystal violet dye
Microscopic oil Micropipette Tips (20- 2000 µl, 200-1000 µl, 1-5mL)
Inoculating loops & wire Micro-slide
Mannitol salt agar
Durham’s (fermentation tube) tube
Ringer solution (Quarter strength)
API Gram (+)(-)selective biochemical test kits/ API 20E
IND reagent TMPD or DMPD (Redox indicators)
Micropipette (20- 2000 µl, 200-1000 µl, 1-5mL)
Glass Rod spreader
Test tube, bottles, caps & stoppers
The bacteria population first needs to be analysis. The water sample will be transferred to the laboratory in a cold chain under aseptic conditions to minimise the risk of contamination
The sample under investigation would certainly contain mixtures of various organisms. In order to assess the bacterial flora population of the samples, it is essential to use selective and non- selective media because no one medium or temperature will support all present organisms. This will provide suitable favourable growth environment for the various group of organisms.
Direct Count Method
The bacteria population of an unknown mixture is investigated using the direct count method. First; the four original samples will be diluted to 10-¹ to 10-³ in peptone / deionised water and 0.1 mL of these dilutions will then be streaked in triplicate with the spread plate technique onto the selective (MacConkey, Blood agar,...
References: APHA (1992) Standard Methods for the Examination of Water and Wastewater, 15th edn. New York: Water Pollution Control Federation
Bergey, David H.; John G. Holt; Noel R. Krieg; Peter H.A. Sneath (1994). Bergey 's Manual of Determinative Bacteriology (9th ed.). Lippincott Williams & Wilkins
Madigan, MT; Martinko J, Parker J (2004). Brock Biology of Microorganisms (10th ed.). Lippincott Williams & Wilkins.
Reasoner, D.J. & Geldreich E.E. (1995). A new medium for the enumeration and subculture of bacteria from portable water. Applied and Environmental Microbiology.49, 1-7.
Please join StudyMode to read the full document