'My Species' -How to

Get involved

This page is to record any diatoms collected through samples taken by our volunteers or contributors in their local areas.

Have you got diatoms in your local area? Where do you find diatoms? How do you collect a diatom sample?
If you would like to find and create your own diatom sample. Some basic instructions on how to collect a diatom sample can be found below. 

Please endeavor to collect your sample as close to your invitation into the Museum date as possible if you wish to find live diatoms!

When you have collected your sample please complete the first stage of the table below and email it to vfactor@nhm.ac.uk with 'My species' in the subject line.
You will create your own slide and (hopefully) establish what species of diatom you have collected in your sample when you visit the museum (on a Thursday).

Your findings will be displayed on Diatoms online in due course looking something like the example below.


My Species’
To be carried out in your local area/home/garden
Collector Name Your name
Date of collection: XX.XX.2014
Habitat: River, Stream, Sea, pond, puddle (please delete/add in as appropriate)

STAGE 2: (to be completed when on site at the Museum)

Number of species found:

1 -5 or more (please delete/add in as appropriate)
Species ID1: Genus , species name  (if known) AND
Species ID2: Genus , species name  (if known) AND image thumbnail
Species ID3: Genus , species name  (if known) AND image thumbnail
Species ID4: Genus , species name  (if known) AND image thumbnail
Species ID5: Genus , species name  (if known) AND image thumbnail

Guidelines on how to collect samples to examine diatoms

Diatoms can be found anywhere water is present. This can mean anything from ponds, lakes and oceans through to raindrops on a ducks’ back or leaf or moisture from soil sediment or waterside rock. HOWEVER in order to obtain a ‘clean’ specimen and to increase our chances of finding some diatoms in your sample we ask that you please collect from the preferred list below (and not soil samples!)

What will I need?

  • Toothbrush
  • 2 X Test tube/mini jam jar/jam jar/small glass contained that can be sealed
  • Small bottle of tap or bottled water
  • Warm clothes and waterproof/hardy footwear!
  • Paper and pen (to record location, habitat, collector, date)
  • Camera (optional)

NOTE: Your safety is of prime importance please be REALLY careful if you are venturing close to a large body of water or river albeit a slow moving one to collect your sample. Please never put yourself at risk to collect your sample. (There will be back up sample at your workshop in case you are unable to collect a sample)

Where should I look for diatoms:

  • from areas subjected to water level change (local pond/lake, puddle, outdoor/indoor swimming pool)
  • from areas of low-velocity river flow (nearby river)
  • from stones (cobbles and small boulders/rocks) covered by abundant filamentous algae

Diatom communities may be detected on substrata by feel (slimy or mucilaginous) or may be seen as a thin golden-brown film covering substrata.

Preferred substratum (i.e. rocks, gravel, natural stone, sand masonry, brick, dirt)

  • Cobbles and small boulders are generally widely available throughout the length of a river from headwaters to lowland stretches.
  • Cobbles and small boulders (rocks) are the preferred substratum for monitoring diatoms in the riverine environment, and almost all diatom indices throughout the world can be applied to the community (i.e. the epilithon) that is found on this substratum.

 Alternative substrata (in order of preference):

  • Man-made objects: i.e. bricks, pieces of concrete, bridge supports, canal walls
  • Submerged aquatic plants surfaces.

Sample methods for different substratum:

Diatoms from rocks, cobbles, pebbles, etc.

Diatoms should be removed by vigorously scrubbing the upper surface of the substratum with a small brush (e.g. clean toothbrush) to dislodge the diatom community. Some diatomists prefer to scrape the substrata with a knife or a spoon as these implements are easier to clean and reduce the possibility of contamination between sites but as you will only be taking one sample a toothbrush is fine.

NOTE: Only the upper side (the side most exposed to flowing water) of boulders should be scrubbed to avoid contamination with sediment that might be present on the undersides of the cobbles.

Sampling from aquatic plants (emerged and submerged)

On the submerged aquatic plants, diatoms should usually be visible as a brown slimy film on the surfaces somewhat exposed to sunlight.

Cut a piece of the plant, brush the surface quite vigorously and clean the brush in the water/tube. For those that are submerged, if the piece of the plant is put into tub/bottle/jar, and shaken vigorously the sediment (film) would usually come out.

HAPPY HUNTING and we look forward to exploring what you've found on 24 March.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith