Algae growth in Sabrina Basin

[dgravlin]

This is the first season that I spent quite a bit of time in the Sabrina Basin. On my last trip in late October, I noticed a disturbing amount of what I assume is some kind of algae in the Hungry Packer drainage. The streams throughout that drainage, leading through Sailor Lake, were covered with this luminescent green grassy algae. The entire bottom of the streams were carpeted. It was worse than I'd ever seen at a low elevation lake. Made us think twice about drinking the water (I don't filter higher elevation flows).

Curious as to the cause, and whether this is typical for that drainage. Did not see the algae when I was there in July or August - at least not to that extent. With no artificial or man made nutrient source, what is feeding this growth? Wish I had taken a photo of it.

[maverick]

Sierra Nature Notes:

Water clarity is affected by number of suspended sediments and amount of algal biomass. Most of the high Sierra lakes are clear (oligotrophic) water lakes, in which we know there is very little sediment runoff and low nutrients. Water clarity is an excellent indicator for increased algal growth. Both sediment inflow, as well as algal growth can be assessed by looking at changes in the water clarity. Greening of lakes typically implied increasing algal growth due to increased nutrient loading. Phosphates arrive in lakes through sediment runoff (from roads and trails), feces of wildlife, and the use of soaps, etc. Thus, greening lakes should be an alert for changing lake conditions and nutrient loads. It is much easier to control the amount of nutrients entering a lake at the onset of eutrophication compared to a lake that has been eutrophic for a while. Once there are excessive levels of nutrients in lakes it is difficult to revert back to an oligotrophic state.

http://www.sierranaturenotes.com/nature ... tWater.htm

More here: https://www.ucdmc.ucdavis.edu/emergency ... -14-09.pdf

[Wandering Daisy]

Water temperature is also a big factor. Five years of drought with low water levels and warmer temperatures likely added to the problem. Since pollutants are diluted by higer water volumes low levels will concentrate phosphates allowing more algae growth. Higher water levels will wash more pollutants downstream (into Sabrina Lake). I suspect it will take several normal to higher snowpack years for the streams to get back to normal, if they ever will.

[dgravlin]

The interesting thing though is that the algae was only present in the Hungry Packer drainage. And it was REALLY dense there. Just one ridge over, in the streams coming out of Midnight Lake, we saw nothing. It's also odd that this was so much more prevalent in water that was just above freezing than it was in the same drainage a few months earlier when the water was much warmer.

[tweederjohnson]

Two words:

Soylent. Green.

Happy Friday!

[Jimr]

This always pops up in my facebook add feed. Notice the "shop" button is green. Always makes me chuckle.

https://www.soylent.com/