Plankton Preservation Flashcards
How soon should fixation and preservation of samples be carried out
Within 5 mins of collection
What is lugols iodine
10g iodine, 20g potassium iodide in 200ml distilled water.
Advantages to Lugols iodine
Adds weight to cells and helps phytoplankton sells sink to bottom of settling chamber.
Not very toxic
Good preservative for soft and hard tissue
What are the disadvantages of Lugols iodine
Breaks down in sunlight. Need to store samples in dark
Can change colouration and impair ID
(Phytoplankton from green to brown)
How are plankton samples stored
Preserved samples stored best in well ventilated room at <25°C
Accurate detailed labeling crucial pencil rather than pen
Two enumeration sample analysis methods
Volumetric
Gravimetric
How does the volumetric method work
Plankton sample filtered through suitable mesh size.
Interstitial water removed with blotting paper.
Filtered plankton transferred to measuring cylinder in 4% buffered formalin
Displacement volume obtained by recording the vol of fixative in measuring jar displaced by the plankton
How does the gravimetric method work
Plankton filtered and blotted dry
Plankton wet weight taken on pre weighed filter paper or tin foil
Sample can be dried in oven at 60°C prior to weighing to obtain dry weight
How does Utermöhl method work
Plankton sample left to settle on bottom of cylinder
Bottom cylinder viewed on inverted microscope
Counts made on microscope
Often used to enumerate phytoplankton
What is the problem with Utermöhl chamber method
Certain forms voutant - do not settle
Example of sub sampling method used for plankton
Folsom plankton splitter
Ensures plankton are evenly dispersed through subsamples
Give example of technological advances in plankton analysis
Underwater cameras capable of recording plankton of organisms at resolution that allows for identification
