sub-tidal surface sediment sampling

[Eric Nicholson]

Hi Scubamanny,

I'm not a diver, and the sample doesn't have to be like a discrete core. Your blended bag idea sounds appropriate. It's not very deep water, so I don't mind getting in the water and sampling by hand - I just need the right equipment/materials. I want a method that is quick and easy and will allow me obtain about 500g of surface sediment (top 1-2cm of substrate, plus any surface detritus). Coring would just be too tedious and time consuming, but I also don't want to lose any sample while trying to get it into a bag or container.

I look forward to any suggestions you may have.

Cheers,

Eric

 

[archman]

How much areal coverage are we talking about here?

 

[Eric Nicholson]

Hi Archman,

From previous scrapings at low tide, I only needed to scrape an area of about 20 square cm (~1-2cm depth, plus whatever surface detritus was there) in order to obtain my desired 500g+ of sediment for substrate analysis. So, if I were to use some sort of shallow coring apparatus with a diameter of ~5cm, then I guess I'd need to take perhaps upto 20 cores to obtain a sufficient sample. I won't have to repeat this every time I collect modern diatom samples at my sites, so taking a several cores at each site may not be such a big deal after all.

Do you have a suggestion as to how I could quickly and easily obtain my desired samples?

 

[CIBDiving]

Help em?!?! I can't even Say that fast

 

[archman]

20 square centimeters? That's the size of a single hand corer, and a teeny one at that! You sure it's not 200, or maybe 2 square meters?

 

[TimAZ]

Could you try a gravel vacuum siphon as used in an aquarium? of course you cant siphon up into a boat but a low pressure pumo like a 201 powerhead with a valve to control flow might do the trick. Let me know wha tyou figure out, sounds interesting.

 

[Eric Nicholson]

Sorry I haven't been checking this forum recently. Thanks to all of you who gave me advice or showed some interest. I eventually found someone to construct a coring device (more like an auger) for me that I can use to get my required sub-tidal surface sediment samples. I haven't properly trialled it yet, but I'm sure it will do the job. This means I won't be relying on pumps or diving or anything more complicated than a long-handled tool employed over the side of a zodiac.

Cheers,

Eric