New Mexico Water eNews

UNM Grad Student Studying Fate of Nutrients Along
the Rio Grande Continuum
by Catherine Ortega Klett, Program Manager

The enrichment of ecosystems with nutrients (i.e, eutrophication) is known to be one of the primary causes of water impairment in the U.S. High loads of nitrogen and phosphorus from point sources (wastewater treatment plants) and distributed sources (agriculture and urban runoff) stimulate bacterial metabolism and algal growth, often causing episodes of hypoxia (low level of dissolved oxygen) due to the subsequent demand for oxygen as microorganisms decompose the excess of organic matter. The depleted oxygen levels in turn may lead to fish kills and a range of other effects reducing biodiversity.

Vanessa Garayburu-Caruso, a master's student at UNM, in collaboration with her faculty advisor Dr. Ricardo González-Pinzón, is conducting a study about nutrient processing along the Jemez River-Rio Grande continuum which spans eight stream orders. Due to the complexity of the physical, chemical, and biological interactions between the solute and the soil, it is still challenging to describe accurately and predict solute transport and nutrients fate in freshwater ecosystems. Therefore, prior studies have been restricted to less complex headwater streams because they are more tractable and make up to 80 percent of the waterways on our planet. The goal of this study is in that sense rather more ambitious: 1) to characterize spatial and temporal differences in nutrient processing in riverbed sediments along the entire continuum (i.e., from first- to eighth-order streams); 2) to characterize uptake limitations by limiting nutrients; and 3) to understand how natural and anthropogenic influences affect microbial populations and metabolic activity along the Rio Grande continuum.

The approach taken is to conduct column experiments to understand nutrient changes in shallow sediment-water interactions along representative sites of the Jemez River-Rio Grande continuum in New Mexico. One representative site for each stream order has been chosen, with the exception of the seventh-stream order where two sites were used to investigate the high incidence of anthropogenic influences originating from the Albuquerque metropolitan area (i.e., discharges from wastewater treatment plants and irrigation channels). For each site, plastic columns packed with three selected types of sediment were deployed in the stream for three months (enough time to allow natural biological communities to colonize the sediments). After the incubation period, the columns were taken to the lab to be tested. Several in-lab tracer experiments using nitrate and phosphates were conducted to further analyze nutrient uptake kinetics and metabolism.

Preliminary results indicate that headwater streams have better nutrient uptake capacity than higher stream orders. More generally, it is expected that these experiments will help determine how natural changes in bacterial communities and sediment composition occurring seasonally along the river continuum tend to define nutrient processing, as well as the relationship between biofilm formation and riverbed sediment diversity. This work will also help to support the development of a new generation of field and lab experiments to quantify nutrient processing in large rivers, where only about 10 percent of all reported tracer experiments have been conducted in the past. The research also should provide insight into how best to manage impaired reaches along the Rio Grande basin.

Garayburu-Caruso, recipient of an NM WRRI Student Water Research Grant, will present final results of the project in a report that will be posted on the institute’s website. Click here to view.

ENMU Student Studying Shoaling Behavior of Fish
in Turbid Water
by Catherine Ortega Klett, Program Manager

Fish often tend to group together for social or survival reasons, and this behavior is known as shoaling. In a study supported by an NM WRRI Student Research Grant, Eastern New Mexico University master’s student, Sabrina Michael, whose faculty advisor is Dr. Marv Lutnesky of the Biology Department, is investigating how shoaling behavior is affected by the degree of cloudiness, or turbidity, of the water. The two species of fresh water fish being studied are the Red Shiners and Sand Shiners, both of which belong to the family known as cyprinids, which also includes such familiar fish as carp and goldfish.

Observations are being made using a 2m circular tank filled with either clear water or with water having high or low turbidity. Fish are placed in the tank in varying group sizes, and their behavior is tracked. To assist in the tracking, an effort is being made, with the assistance of Jon Patman, a computer science graduate student, to develop software that can automate the otherwise tedious and difficult process of tracking and identifying fish. The development of this software has become one of the main goals of this project, and it will be made freely available to other researchers who face similar logistical problems in their work.

Preliminary results show that the shoaling behavior of the two species is very similar. Differences in shoaling duration and group size does depend on the environmental conditions. Both species were unable to form even small shoals of up to five fish for periods of time longer than about 30 seconds in turbid waters. In clear water these limitations are generally not observed. Such results may have implications for any water agency that might be interested in how water quality could negatively influence behavior, and therefore populations, of fishes in their jurisdiction.

This study is in its second year of support by NM WRRI. The results of Sabrina’s study will be posted in her final report on the NM WRRI website. Click here to view.

NM WRRI Student Water Research Grant Recipients Present Research
by Catherine Ortega Klett, Program Manager

On April 23, NM WRRI Student Water Research Grant recipient Joseph Hernandez and his team presented a poster at NMSU College of Engineering’s second annual Student Capstone Design Competition. All NMSU engineering Capstone students were in attendance and displayed work done this year. The design team for the NM WRRI grant project included students from the Department of Electrical Engineering: McDonald Garley, Felipe Farias, Jesus Moreno, Xaviar Enriquez, Saleh Aldaihani, and Abdullah Alluhaidan, working with their faculty advisor Dr. Nadipuram R. Prasad. The project is entitled Hydro-Weirs: A Scalable Revolutionary Low-head Hydropower Technology. The students will prepare a final report on their project and it will be posted on the NM WRRI website. To view click here.

Water Science & Management Graduates Honored
at Reception
by Catherine Ortega Klett, Program Manager

New Mexico State University’s Water Science & Management (WSM) graduate degree program held its annual graduation reception on April 28. NM WRRI Director Dr. Sam Fernald welcomed everyone and talked about the program’s inception in 2012. WSM graduates were recognized by their faculty advisors during a medal ceremony. Steven Maestas graduated on May 14 with an MS in WSM. Ian Hewitt, Alejandro Raul Lopez Moreno, and Claudia Trueblood will be completing MS degrees in August 2016. All students talked about their research projects and were acknowledged and encouraged by guest speakers Dr. Jim Libbin, Agricultural, Consumer & Environmental Sciences Dean and Dr. Loui Reyes, Graduate School Dean.

The NMSU interdisciplinary graduate degree program currently has 29 students enrolled representing 10 countries with 10 students having graduated from the program. “The WSM program has increased enrollment in graduate education and increased water research; it is supported by coursework in all colleges at NMSU, particularly in the founding departments of civil engineering, geography, plant and environmental sciences, agricultural economics/agricultural business, and animal and range sciences,” according to Patrick Natoni, WSM Program Coordinator.