What is Macrophyte biomass

Please describe it with great detail

Macrophyte. This term is used as a synonym for hydrophyte, a plant that lives in water as an emergent, submerged or floating and has vascular tissue.
http://www.eoearth.org/article/Macrophyt…
http://dnr.state.il.us/wetlands/page30.h…

Biomass is the total mass of the species of interest in the system being considered. For example: Submerged eel grasses in a given region or volume of space.