Measuring Submerged Aquatic Macrophytes (SAMs)

The Role of Submerged Aquatic Macrophytes (SAMs) in a Montane Grassland River Ecosystem. 2011

Total Biomass (g/m2) by Species

Elodea canadensis (Canadian waterweed): Native to New Mexico. This plant is the major player in the SAMs in the East Fork. A prolific grower that can reach up to 100cm, Elodea forms extremely dense stands in slower moving water. Ranunculus aquatilis (white water buttercup): Native to New Mexico. Easily recognized by its small, white ‘buttercup’ flowers. Often creates dense single species monocultures. Prefers higher velocity areas. Potamogeton richardsonii (clasping-leaved pondweed): Native to New Mexico. Leaves are sparsely & alternately spaced along the stem, with wavy margins. Often found in the East Fork Jemez River mixed with Elodea or Ranunculus.


In supporting New Mexico EPSCoR’s mission to better understand how water quality factors affect New Mexico’s sources of water, this study concentrates on understanding the life cycle, total primary production, nutrient cycling, oxygen production, and other key ecosystem contributions made by submerged aquatic macrophytes (SAMs) in the East Fork Jemez River (EFJR) in the Valles Caldera.


Virginia F. Thompson, Rebecca J. Bixby, and Clifford N. Dahm, Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA

The East Fork Jemez River (EFJR) is located within the Valles Caldera National Preserve.

About the Researchers: 

Virginia Thompson currently attends the University of New Mexico, and is working for .. Read more


Reading the Graph

1. How many times did the researcher collect data? On what approximate dates?

2. How many different species of submerged aquatic macrophytes (SAMs) did the researcher collect?

Making Inferences

3. Based on the information presented in the graph, to what do you attribute the decrease in biomass between mid summer (approx. June 15) and late summer (approx. Sept 1)? Be sure to account for both the fire and the monsoon flood events.

4. Using the graph and what you know about NM’s climate, predict what the biomass would be for each species of SAM if the researcher had collected data on November 15.

Digging Deeper

5. Write a hypothetical email message to the researcher suggesting a plan for future data collection. Include the question you would like answered, the species to be sampled, and the number and date for data collection.

click here to view the answers.