You might want to bookmark this link It's worth having for a reference.

To me it looks like a type of Pondweed, very possibly Sago Pondweed. Then Duckweed, then Cattails for sure. Not completely sure about the last one, look on that website for submerged plants.


www.hoosierpondpros.com

[Linked Image from lh6.ggpht.com]
http://www.pondboss.com/subscribe.asp?c=4
3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).