Pond Boss Forums AQUATIC VEGETATION Identifying plants Film over the pond

Pollen is easy to detect just invite an alergic person along, look at their eyes, nose and listen for sneezes.

Or if tou don't want to be rud, place any thing with glossy surface, mirror, bucket of water or leave your car(clean) parked next to the pond.
If it's pollen it will usualy be visable on the glossy surface, within houers.

This is my unsientific trix, to rule out/in pollen.

Update on "Film Over The Pond". Here are results and comments to Bennie after examining water with film from his pond.

Most of the stuff based on biovolume in your last sample you sent was dead organics (detritus) - see attached No 1. During all my scans of the sample I did not see one recognizable pollen grain.

From no or low magnification, it mostly looks like brown 'dirt'. Usually the films that have a strong color are mostly composed of small celled algae either as single cells, colonies or filaments. Your sample was not the typical bloom-film conditions. On higher magnification there were numerous small algae present but they did not make up the majority of the sample. The dominant living cells in your sample were a type of single celled green algae (attached No 2). I was not able to identify specifically what they were because I am pretty sure they were in a resting stage (probably stressed) and not actively growing. Single celled flagellated green algae can often go into a resting stage and then they all look basically alike. I think they were a resting stage of Tetraselmis cordiformis (old name: Carteria) or maybe some species of Chlamydomonas sp. Both can form thin green surface films. Numerous other algae species can also form green films. I saw a few regular or normal celled Tetraselmis in the sample. The single celled alga contributed to most of the green color of the film.

I suppose it is not unusual to periodically have lots of dead organics on a pond surface esp when the pond is old and has a large input of decomposing organic materials such as leaves and organics from the watershed and those that have grown in the pond. Warm water(80+F), calm conditions or no wind trends to favor development of films and scums on pond surfaces. Low density dead organics can sometimes easily move into the water column and eventually float. Sometimes films are mostly dead stuff and sometimes mostly living stuff depending on conditions. If you would have collected the sample early in the development of the film the living stuff would have been 'fresher' and easier to identify or verify what was growing. The heavy rain and weather that occurred and broke up the film could have altered the condition of cells in the film/scum.

Let me know if you have any questions.

Great work Cody. I figured it was single celled algae, you call it a film, I call it scum. Same thing to me. But like you said, could be a lot of different possibilities, and hard to positively identify when they are off. I wonder if they are ever on when they get up to the surface? Do they float up dead or dormant? Generally speaking of course.again, thanks for the excellent lab results.

One thing I haven't brought up yet but you might notice from the picture I posted--this pond is under the jurisdiction of a subdivision that does nothing to it. In fact I think their practices are detrimental. I say that because

1) they mow up to the water
2) they fertilize up to the water and around a catch basin that drains into the water.

Dead organics make sense because this could simply be from them mowing and blowing dirt off the sidewalk into the pond.

I plan on putting up a small "grow zone' sign and talk to the mowers to keep a buffer zone between the pond and the trimmed grass--it can only help.

Thanks for all of your input and conversation on this topic--I truly appreciate it.

Other than the film, things are living and thriving. Frogs, minnows, snails, turtles--I just need to get some gamefish in there. I saw a turtle haul in a big snail today--that was pretty cool to watch. So much going on down there.

Bennie

Normally many of the non-FA algae comprising the films/scums are thriving and not dead or dormant. His algae was not really dormant but it was stressed and most of it had lost its flagella (swimming hairs). I did not have him preserve the sample due to close proximity to me. Some of the stress could have been from collection and sample being in the dark for a couple days. Some algae types that are scum formers do not have flagella and thrive on the surface.