Question

Why are hetercysts in cyanobactiria critical components of the nitrogen cycle?

Answer 1

Since this is not my area of expertise, I searched Google under the key words "<I>heterocysts cyanobacteria nitrogen</I>" to get these possible sources: (It helps more if you spell the key words correctly.)

http://209.85.173.104/search?q=cache:5Ees-C7FBmQJ:www.esf.org/index.php%3FeID%3Dtx_ccdamdl_file%26p%255Bfile%255D%3D4366%26p%255Bdl%255D%3D1%26p%255Bpid%255D%3D3831%26p%255Bsite%255D%3DEuropean%2520Science%2520Foundation%26p%255Bt%255D%3D1205614447%26hash%3Dd669d5d702b43e0daf21597eff261f8b%26l%3Den+heterocysts+cyanobacteria+nitrogen&hl=en&ct=clnk&cd=1&gl=us&client=safari
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TD1-3TVX7D7-9&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=d036dc71d03b29149d0534970593b189
(Broken Link Removed)
http://www.earthlife.net/prokaryotes/cyano.html
http://www.plantphysiol.org/cgi/reprint/100/1/157.pdf

In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.

I hope this helps. Thanks for asking.