Diario de spongeman

The first dry pool to be examined on Bulls Hill Fire Trail revealed quite a few beasties (see journal post 1), and quite a few improvements to make in the method.
It also pointed out the difficulty of making non-expert identifications of microorganisms and mini-macroinvertebrates. There is limited easily available literature for many Australian taxa and many groups have little information. A steep and fragmentary learning curve.
On Sunday a new batch of material will be collected from a rocky hilltop behind Umina on the NSW central coast. Some years ago, following wet weather, the rockpools here contained large numbers of conchostracan crustaceans.
An improved container will be used to incubate the soil sample which keeps most of the sandy sediment out of the water. Mineral particles played havoc with microscope slide preparation.
I'll also be treating portions of the residue of water and organic residue from the first sample separately with;

1. hydrogen peroxide, and

2. nitric acid,
   to try to separate the frustules of diatoms from organic remains and to clear the organic portion of the diatoms. Hopefully this will allow a better chance to more confidently identify more of the diatoms present.

Still hopeful someone out there might find this interesting. All and any comments will be gratefully received.

After following a few iNat contributors who provided some amazing posts based on microscopy a project sprung to mind. Thanks to @closterium_mysterium, @shanesmicroscope and @mnold1 for the inspiration. While I normally chase the plants and animals in the Aussie bushland, and Australian freshwater sponges and beasties, a microscopic view of the world seemed to offer new horizons ...so...

The Hilltop Temporary Rockpool Invertebrates

The bushland on the central Coast of NSW is dominated by varied eucalypt forests, scrubland, heath and patches of rainforest. This often sits on top of rocky and sandy ridges, valleys and hills overlaying sandstone geology. On top of many hills there are exposures of sandstone containing depressions which become small pools after rain. Most dry out completely within a short time, but during their brief watery existence become small freshwater habitats for a variety of invertebrates and microorganisms (along with occasional frogs).

This project will attempt to document some of these invertebrates and microorganisms.

Method

1. A small sample of the soil and vegetation surrounding a dry pool will be taken and retained at room temperature for a few weeks.
2. A small amount of water will be added to the sample to cover the sample to about half its depth and surround it with an area of free water. This will be kept at room temperature.
3. After several days and for several weeks following the water will be sampled by dropper and examined microscopically. Any invertebrates and microorganisms observed will be photographed and the photos posted to iNat. Identifications will be made as possible.
4. A New Post will be written at the end of each sampling project to describe the outcomes and link the observations together.

Trial sample - Bulls Hill Fire Trail

On Bulls Hill fire trail a rocky outcrop of sandstone topped by an electrical transmission line tower contains several depressions which fill with water after rain. These stay filled for periods from a few days to a few weeks depending on the weather. The first photo shows the site. The pools are surrounded by soil with mosses which dry out fairly completely in hot dry weather, and small plants. This surrounding vegetation is usually inundated after rain and so provides a submerged boundary to the ponds.

1. A small sample of soil and moss was taken and kept in a container for several weeks at room temperature and open to the air.
2. On 1/8/24 a small amount of water was added. This covered the soil and mosses to about half their depth, with an area of clear water around them, extending out about 2 cm and about 2 cm deep. This was kept at room temperature, open to the air.
3. From a few days later samples were taken by dropper and examined microscopically. The resulting observations are attached. Many organisms were too small, too fast or just not adequately recorded to include, so the resulting observations represent a tiny subsample of this little ecosystem. I'm still sampling the material and will continue to do so for a while yet.

This has really been a satisfying project, so contributions to identification, or thoughts on the project or just general comments will be very gratefully received.

The next project will use material from a rocky outcrop behind the coastal town of Umina where conchostracans have been found in the past. See you then.