Finding Diatoms

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lorez
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Finding Diatoms

#1 Post by lorez » Thu Dec 01, 2016 2:46 am

I finally had an opportunity to collect some sand for the diatom project and before I sent it off I took a few minutes to check for a reasonable population. I was pleasantly surprised. In a single drop of water I found at least a dozen different types. I drew the water off the top of the sand sample after letting it sit for an hour. The sample size was about a cup of sand which was covered by a half inch of lake water (in a 20oz cup).

The encouraging part of this is that it is not necessary to carry a microscope to the collection site.

lorez

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zzffnn
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Re: Finding Diatoms

#2 Post by zzffnn » Thu Dec 01, 2016 3:01 am

Wow, a dozen types per drop? That would beat my best find so far - which was about 8-10 forms per drop, from Pensacola (Florida) beach sand.

Usually, I find about 4 types per drop, from either fresh or brackish or sea water.

If Rod find lots of interesting forms from that sample, would you please go back and gather a bit more sand for us? I will pay all costs. Thank you!

charlie g
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Re: Finding Diatoms

#3 Post by charlie g » Thu Dec 01, 2016 3:17 am

Hi, lorez and all diatom speculators/ 'diatom twitchers'. It is so importnt to note that living diatoms of a great variety of diatom tribes are quite mobile...quite active.

Depending on your specific 'diatom twitching' site...nest a styrofoam cup half into the sediment-muck..before high sun/noon at that collection time. Often mobile diatoms will march up above the sludge level...and these hordes you collect.


Open water surfaces can be sampled by simple 'diatom-rafts' of...yes, rafts of styrofoam...anchor a few shards of styrofoam ( your collection rafts)...by string to a shore anchor twig...collect after a week.


Please remember that oh so many types of diatoms are mobile...and will collect on surfaces you place for them...vrs...scoops of sediment where diatoms are often functioning. I guess all I suggest is...use the fact that many healthy diatoms are quite mobile...to herd them for collection. charlie guevara

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lorez
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Re: Finding Diatoms

#4 Post by lorez » Thu Dec 01, 2016 3:57 am

Lots of good suggestions, Charlie g. I spent all of 20 seconds at the pond's edge scraping the top of the sand surface into my cup. It was raining and trying to snow.

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Re: Finding Diatoms

#5 Post by Charles » Thu Dec 01, 2016 11:58 am

Hi lorez,

Is this a marine or fresh water sample? I am looking to expand my samples and am willing to trade sand samples or maybe a type slide of your sample? :)

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lorez
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Re: Finding Diatoms

#6 Post by lorez » Thu Dec 01, 2016 4:56 pm

Charles,

I could not be any farther from a marine environment. I'm in NE. I will be happy to send you a sample.

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zzffnn
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Re: Finding Diatoms

#7 Post by zzffnn » Thu Dec 01, 2016 7:10 pm

lorez wrote: I spent all of 20 seconds at the pond's edge scraping the top of the sand surface into my cup. It was raining and trying to snow.
Sorry to hear about the trouble in collecting.
It is amazing how many diatoms are there, in such a cold environment.

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lorez
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Re: Finding Diatoms

#8 Post by lorez » Thu Dec 01, 2016 8:09 pm

Hello all,

I certainly did not mean to imply that there was any difficulty in collecting the sample, it could not have been easier. I walked down the steps to the 'beach' (lake side) and used my cup to scrape the surface of the sand.

I was very pleasantly surprised at the variety if found with so little effort. Since there were no rocks to scrape I don't have the concentration of that method of collection, but the variety was certainly encouraging.

We are on the cusp of winter here after enjoying such a pleasant fall and the day I had time to go collecting was the day the cold winds began to blow. We enjoy the continental extremes of weather, but not as bad as North Dakota.

lorez

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Dale
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Re: Finding Diatoms

#9 Post by Dale » Thu Dec 01, 2016 10:37 pm

I shall stick to collecting from marine environments, like the warm and sunny beach where
South Pacific was filmed. Your comment, Lorez, well taken, thanks.
Dale
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Re: Finding Diatoms

#10 Post by zzffnn » Thu Dec 01, 2016 10:57 pm

lorez wrote:Hello all,

I certainly did not mean to imply that there was any difficulty in collecting the sample, it could not have been easier. I walked down the steps to the 'beach' (lake side) and used my cup to scrape the surface of the sand.

I was very pleasantly surprised at the variety if found with so little effort. Since there were no rocks to scrape I don't have the concentration of that method of collection, but the variety was certainly encouraging.

We are on the cusp of winter here after enjoying such a pleasant fall and the day I had time to go collecting was the day the cold winds began to blow. We enjoy the continental extremes of weather, but not as bad as North Dakota.

lorez
How big were the sand particles in your lake sample, around 300 microns or much smaller? If sand particles are much bigger than diatoms (say in 300 microns range), they would be very easy to remove by filtration.

Sand particles near me is around 150 microns though and has lots of organic detritus :cry:

I collected a plant sample from a brackish bayou (Armand Bayou, TX), also on the day it turned cold. Surprisingly, there were quite many diatoms there. The sample is quite clean, after I squeezed off water from the plant and let it precipitate.

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lorez
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Re: Finding Diatoms

#11 Post by lorez » Thu Dec 01, 2016 11:43 pm

How big were the sand particles in your lake sample
Whoa ! It's getting too complicated. I am just a novice at the sand collecting, but am slowly adding to my small collection. I do not, at the moment, have a sieve with which to measure grain sizes, but am aware of the variations within samples from the same location.

What's really great is that there are so many who have volunteered to help me in this inane effort. I've got e-pen pals all over the planet.

lorez

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Re: Finding Diatoms

#12 Post by zzffnn » Fri Dec 02, 2016 12:00 am

Just saying, if your sand particles are a bit bigger than your diatoms (which typically less than 200 microns, more often around 20-120 microns), then you may be able to select a sieve to remove sand easily. Otherwise, removing tiny sand particles are difficult.

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lorez
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Re: Finding Diatoms

#13 Post by lorez » Fri Dec 02, 2016 12:21 am

I think you are absolutely correct. It sounds like a sieve set is on the Christmas list. It's a good thing I know that Santa fellow personally.

lorez

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Dale
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Re: Finding Diatoms

#14 Post by Dale » Fri Dec 02, 2016 3:46 am

What span of mesh sizes should one ask santa for?
Dale
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lorez
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Re: Finding Diatoms

#15 Post by lorez » Fri Dec 02, 2016 4:05 am

I am probably not the best source for reliable information, but here is a link that has some interesting choices.

http://www.turf-tec.com/BS1lit.html

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zzffnn
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Re: Finding Diatoms

#16 Post by zzffnn » Fri Dec 02, 2016 4:23 am

Dale wrote:What span of mesh sizes should one ask santa for?
Dale
Dale,

Didn't you already buy and receive that steel sieve that I showed you? It has pore size of around 300 microns, which is perfect for removing big sand particles from diatoms.

There is an equation to calculate pore micron size from mesh value, but I don't have it now.

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Dale
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Re: Finding Diatoms

#17 Post by Dale » Fri Dec 02, 2016 4:49 am

I got the #210 and #500, and I assume the # number is the same as microns.
The small squares work well over petri dishes, but for larger samples having the
mesh in a frame seems useable. The sieve set Lorez referenced was way too
expensive, but very attractive. I also need to attach a scoop/sieve to a long stick
to collect sand from little pockets at a very dangerous lava rock outfall.
Dale
just found the conversion chart at universalfilters.com
B&L Stereozoom 4. Nikon E600. AO Biostar 1820.

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Re: Finding Diatoms

#18 Post by zzffnn » Fri Dec 02, 2016 5:16 am

Dale wrote: I also need to attach a scoop/sieve to a long stick to collect sand from little pockets at a very dangerous lava rock outfall.
You probably don't need a sieve to collect diatoms. I use my sieve to let diatoms pass through (into a retainer) and sand particles remain on sieve, then I toss away the sand.

What kind of lava rock outfall would that be and where? That sounds interesting. If you do find diatoms there, they would probably look different than common ones.

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Dale
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Re: Finding Diatoms

#19 Post by Dale » Fri Dec 02, 2016 5:45 am

It is the Lumahai Beach, home to one of the worlds richest olivine sand deposits, and the most
dangerous beach. Lumahai means bad water. Any aerial view will show the lava
spike at the West end. I found a Hawaiian lifeguard forum, and they advised using a scoop
taped to a long stick, so as to not climb on the lava. They said it is a frequent activity, and
so is drowning!
Dale
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Re: Finding Diatoms

#20 Post by zzffnn » Fri Dec 02, 2016 12:43 pm

Dale wrote:It is the Lumahai Beach, home to one of the worlds richest olivine sand deposits, and the most
dangerous beach. Lumahai means bad water. Any aerial view will show the lava
spike at the West end. I found a Hawaiian lifeguard forum, and they advised using a scoop
taped to a long stick, so as to not climb on the lava. They said it is a frequent activity, and
so is drowning!
Dale
You would probably find sulfur-consuming diatoms there :)

So if you want, you can climb on lava ? :shock:

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Re: Finding Diatoms

#21 Post by billbillt » Fri Dec 02, 2016 3:40 pm

Dale wrote:What span of mesh sizes should one ask santa for?
Dale

Here is an Ebay link to a set of mesh screens of various grid sizes:

http://www.ebay.com/itm/4-x4-Stainless- ... 33c2d20645

BillT

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Dale
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Re: Finding Diatoms

#22 Post by Dale » Fri Dec 02, 2016 10:58 pm

Thank you Bill, I missed that option. I intend to cut them into circles to place
into a Buchner funnel.
Dale
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