Apatococcus ammoniophilus - new name for Klebsormidium crenulatum (Hormodiopsis crenulata) - see all my posts

Ever since Allan Pentecost showed me some Klebsormidium crenulatum in 2009 on a 50 year old wooden gate near Gordale Beck, I have been noticing this alga..  spreading. spreading..  (Old posts first, newer ones at end). 

I have written many posts about it.

Paragraph insert in July 2025:

Apatococcus ammoniophilus  - this is its new name. 

I learned this in our  BLS Lichen Chat and Improvement group in July 2025. One of the participants (Juliet) told us about a Danish scientific paper describing its new name, by Søchting et al.... and including a picture of how it was interrupting the Danish Christmas Tree industry by growing over conifers.

In Denmark they call it 

Gylletråd - which translates as Golden Thread (though I would give it the name it Green Velvet or Green Blotting-paper Lichen myself)

https://gylletraad.dk/en/front-page/

   In 2018 I made a poster display on the topic for the Yorkshire Naturalists' Union Conference - It had by then changed name to Hormidiopsis crenulata (Kuetz.) Heering  
   Allan used the English name "Nuisance alga" - because is growing over lichens. It is spreading because there are so many nitrogen compounds in the air from intensive factory farming.

 Read link 1 below first. (And see diagrams about nitrogen deposition at the foot of this page)

1. Gosh! 100 years of Harber-Bosch   Sept 2013 - READ THIS FIRST - it explains a lot.
2. The Rainforest Fund Project: Lichens of Malham Tarn House 2  March 2012 
3. Klebsormidium crenulatum - filamentous green alga on CCG walk to Ryeloaf Hill   Aug 2012
4. Klebsormidium crenulatum - near Helwith Bridge  Feb 2013
5. YNU Bryophytes visit to Ponden on W Yorks /Lancs border - The mosses of Heathcliff and Catherine 
6. Lichens at Horton in Ribblesdale Churchyard 15 Oct 2014
7. Rombald's Moor/Skipton Moor on Forest Church Walk 23 Oct 2014
8. Klebsormidium near Langcliffe Lochs 26 Oct 2014
9. Klebsormidium near Sannet Hall, 18 Nov 2014 It really is dire here.
10. Lofthouse - Nidderdale Lichens 13 Oct 2017
11. Klebsormidium on grit wall near Giggleswick School - Oct 2017
12. Klebsormidium on fence-posts above Pen-y-ghent Gill
13. Klebsormidium at Ribblehead Station Dec 2017

Diagrams below:  Left NITROGEN DEPOSITION;
Right: AMMONIA CONCENTRATION 

 I especially notice it on siliceous rocks high in the hills of the Pennines. I feel that the Klebsormidium / Apatococcus grows because of Nitrogen Deposition (e.g. due to heavy mists and rainfall in the mountains) - rather than just ammonia concentration.. But then I don't live next to a chicken farm -  It is likely due to a combination of both.