VOL. CXVIII, NO. 139
DAILYBAROMETER.COM
MONDAY, MAY 16, 2016
OREGON STATE UNIVERSITY
Dams cause trouble for aquatic insects
‘Hydropeaking’ causes tide shifts in rivers, disrupts ability to reproduce
CREATIVE COMMONS
By Nick Miller Practicum Contributor
A recent Bioscience Journal publication revealed that aquatic insects are having difficulty reproducing due to hydroelectric dams changing the tides. The article, titled “Flow Management for Hydropower Extirpates,” was published on May 2 and written in part by David Lytle, an integrative biology professor at Oregon State University. In it, Lytle discussed the effects of hydropeaking on the surrounding insect life of the rivers that have hydroelectric dams. According to the Bioscience journal, Hydropeaking is when the dam starts to move more water through its systems and changes the overall flow of the river it is in. This shift in flow changes where the shoreline of the river is sitting. “Hydropower is often used to supplement
power into the grid during times of peak demand,” Lytle said. “What that does is create a pattern of fluctuations called hydropeaking.” Lytle said that this cycle of fluctuation is confusing to the insect species of these rivers and that they are having trouble coping to the rapid changes. The journal entry focuses on three types of insects: the mayfly, caddisfly, and the stonefly. These insects rely on having stable nearshore areas where they can place their eggs for reproduction, which is referred to in the journal as “recruitment.” The constantly shifting waters make it difficult for the eggs to survive beyond their earliest stages. “Most of these insects use the edges of rivers to lay their eggs,” Lytle said. “In a hydropeaking river, the place where an insect (lays) its eggs may be dry within twelve hours because of those fluctuations in water levels.” The dryness of these areas causes the oth-
erwise-healthy eggs to dry up as well, causing insect eggs to dry up and die. Lytle also said that hydropeaking can also have an effect on the life cycles of animals beyond insects. “It’s been shown to have significant effect on not just the invertebrates, but also the fish,” Lytle said. Desiree Tullos, associate professor of river engineering with OSU, agreed with this sentiment. Tullos said that there is a possibility for hydropeaking to affect the reproduction cycles of fish, such as salmon. “They build their nests, what we call reds, within a shallower zone of water,” Tullos said. “So I could imagine we may see some type of effect.” The journal suggests some ways to avert these developments, one that Lytle refers to as ‘Take the Weekend Off,’ in which the river levels are kept low during a couple of days, allowing
the insect species time to plant their eggs in a way that they can stay wet and avoid drying up. “It’s possible that (the ‘Take the Weekend Off’ idea) could give them enough of an advantage to have a higher degree of recruitment and an increase in population sizes,” Lytle said. Tullos was somewhat skeptical of this idea. She added that it might take more than just a couple of days to allow these insects and fish to lay their eggs and incubate. However, she thinks that the idea is helpful to a conversation that will require a lot of thought and discussion. Both Lytle and Tullos said that there is going to be further research needed in order to find more effective ways to protect these ecosystems. “As we learn more about the mechanisms which hydropeaking changes the ecosystem downstream, we can come up with better ways of generating that electricity,” Lytle said. baro.news@oregonstate.edu
OSU researchers design more sustainable cement The Daily Barometer
OSU researchers recently discovered a new approach to producing cement which, if widely implemented, could offer environmental benefits, such as reducing greenhouse gas emissions and water consumption, as well producing a more durable concrete. A recent study published in “Construction and Building Materials”, written by engineers from Oregon State University, Purdue University and Solidia Technologies, outlined the new
form of producing cement, called carbonation. “With conventional concrete, water comes together with cement to form a glue, called hydration,” said Jason Weiss, the Miles Lowell and Margaret Watt Edwards Distinguished Chair in the OSU college of engineering. “In this newer type of concrete, instead of water reacting with cement, it’s carbon dioxide, water and cement reacting.” This new process, called carbonation, would reduce carbon dioxide emissions during pro-
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duction and would be environmentally sustainable, according to Weiss. “When cement is manufactured, carbon dioxide is produced, and we use so much concrete around the world that there tends to be a lot of carbon dioxide released into the atmosphere,” Weiss said. “The process of manufacturing this new cement would result in less carbon dioxide because the reaction consumes, instead of produces, carbon dioxide.” Not only would this carbon-
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ated cement reduce greenhouse gas emissions, it would prove to be more durable due to its ability to be resistant to deicing salts, Weiss said. “Conventional concretes have something called calcium hydroxide that’s part of the glue that forms, and deicing salts react with it to damage the concrete,” Weiss said. “This new concrete doesn’t have calcium hydroxide, making it less likely to be damaged.” The production of carbonated cement would be similar
in cost to conventional cement. Because two to four tons of cement are produced each year, the current manufacturing system is not very open to change, which would be the largest obstacle the production of carbonated cement would face, according to Weiss. “The biggest challenge is we have been producing conventional concrete for a long time,” Weiss said. “The industry is setup to produce conventional concrete, not carbonated concrete, which may take time to
reverse.” Solidia Technologies is currently working on producing the materials necessary to manufacture carbonated concrete. In order to integrate this new cement, OSU engineers are working towards public awareness, according to Weiss. “Right now people need to understand what this concrete is, its background, how it fits into building codes and what its benefits are,” Weiss said. “Right now we are working with Solidia Technologies to do this.” baro.news@oregonstate.edu
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