2,817 research outputs found
Iron, Molybdenum and Phosphorus Limitation of N2 Fixation Maintains Nitrogen Deficiency of Plankton in the Great Salt Lake Drainage (Utah, USA)
No full textThe factors that directly and indirectly restrict the productivity of the world\u27s lakes, streams, and oceans have been studied for decades, but no clear picture has emerged that explains when and why particular nutrients will limit algal growth. In many lakes phosphorus often controls phytoplankton production (SCHINDLER 1977), but numerous freshwater and marine systems are frequently limited by supplies of nitrogen or micronutrients. A priori, we would not expect nitrogen to become limiting because cyanobacteria and other nitrogen fixing organisms can utilize the vast supply of N2 gas to produce ammonia (SCHINDLER 1977). However, systems chronically limited by nitrogen are frequently observed, suggesting that some factor(s) is restricting the fixation of N2.
Four hypotheses have been suggested to account for the limitation of nitrogen fixation in aquatic systems. First, STEWART et al. (1970) and SCHINDLER (1977) have demonstrated that supplies of phosphorus can limit N2 fixation in some lakes. Secondly, iron, a component of the nitrogenase enzyme system, has been indicated to limit N2 fixation in lakes (WURTSBAUGH & HORNE 1983, WURTSBAUGH et al. 1985). RUETER (1982) has suggested that N2 fixation in the oceans may also be limited by iron. Thirdly, the uptake of molybdenum, another metal necessary for nitrogenase, has been suggested to limit fixation in an estuarine system (HOWARTH & COLE 1985). Finally, PAERL et al. 1987 have provided evidence that the addition of organic matter (sugars) to natural waters promotes the formation of anoxic microzones in bacterial aggregates; this, in turn, allows oxygensensitive N2 fixation to increase.
Here I report on factors that control algal production in three contrasting lentic systems located in the Great Basin of North America. I first demonstrate that algal growth in these systems is directly limited by supplies of nitrogen, and then show that phosphorus, iron and molybdenum may all be important in regulating nitrogen fixation
Recording of interview with Wayne Muller
No full textMuller is an author, psychotherapist and minister living in Fairfax, CA. Muller met Nouwen as a student at Harvard Divinity School (Cambridge, MA) from 1982-1985; Muller took Nouwen's Introduction to the Spiritual Life course in the Spring semester of 1983.1 audio cassette (1 hr., 30 mins.)Title based on contents of the item. ; Reference copies of the audio cassettes are available (located with originals). ; Located in audio cassettes box 13. ; No reproduction of this material without permission of the Archivist. ; The interview has been transcribed and is available electronically and in hard copy. ; Digitized February 3, 2011.For more information please contact Special Collections, the University of St. Michael's College.Item consists of one audio cassette (SR2007 66 66 53) of an interview with Wayne Muller conducted by Sue Mosteller, csj on October 31, 2004 at the San Damiano Retreat Centre in Danville, CA. Themes present in Muller's interview include death, grief, Buddhism, fundamentalism and Nouwen's legacy
Wayne Sawchuk Photography
No full textWayne Sawchuk is an photographer, conservationist, and author. Wayne Sawchuk's cameras are constant companions on his long journeys through northeast British Columbia's Muskwa-Kechika wilderness area. His photos reflect his broad diversity of wildlife and wilderness subjects, and have been widely published in Canadian Geographic, Beautiful BC, The National Post, Explorer Magazine and BC Oudoors, among others
In researching the history of rum and rum cocktails, author Wayne Curtis bought
No full textIn researching the history of rum and rum cocktails, author Wayne Curtis bought an out-of-print copy of Trader Vic\u27s Book of Food & Drink that once belonged to Maine author Kenneth Roberts (1885-1957). On a blank page, Curtis discovered Roberts\u27 well-crafted description of inventing a recipe, with scratched out and recast words
Brine Shrimp Ecology In The Great Salt Lake, Utah
No full textHypersaline lakes are noted for their simple communities which facilitate understanding ecological interactions (Williams et al. 1990; Wurtsbaugh 1992; Jellison and Melack 1988). Nevertheless, we still cannot easily predict how environmental changes will effect the population dynamics in these lakes, at least in part because even these simple ecosystems may be more complex than we .realize. Many hypersaline lakes are dominated by the brine shrimp Artemia spp. The production of brine shrimp is often very high because the terminal, saline lakes accumulate nutrients that make them rich, and because the short food chains in them (nutrients--\u3ephytoplankton--\u3ebrine shrimp) minim ize the loss of materials and energy through trophic-transfer inefficiencies (Lindeman 1942). Brine shrimp are not, however, the end of the food chain. Waterfowl and shorebirds often depend heavily on the shrimp for food (Cooper et al. 1984; White et al. 1992). The shrimp and their cysts are also harvested commercially, primarily to support a world-wide shellfish and finfish aquaculture industry
Letter from W. [Wayne] M. Collins to Hajime Kishi, January 8, 1952
No full textThis letter from Wayne M. Collins, a lawyer, explains that Katsumi Kishi and Masao Kishi are native born Peruvian citizens and therefore cannot be deported to Japan. Mr. Wayne Collins goes on to explain that there should be no cause for alarm at any potential deportation.Collection of notes, articles, correspondence, photographs, and term papers collected by Yukio Mochizuki, a student at CSU Dominguez Hills, while researching Japanese American incarceration and Japanese Peruvian internment during World War II
Wayne Ude, 12th Annual ODU Literary Festival
No full textWayne Ude is the author of Buffalo and Other Stories, 1975; Becoming Coyote, 1981; and Three Coyote Tales, due out this fall. His current project is a novel-in-slow-progress, tentatively titled Home Place. He is the director of Creative Writing at Old Dominion University, and also director of the ODU Literary Festival
Letter from Wayne M. Collins to Hayao (Sam) Chuman, March 20, 1958
No full textA letter from Wayne M. Collins to Hayao (Sam) Chuman regarding a questionnaire for him to fill out for a supplemental affidavit. The back of the letter has a handwritten note for Wayne by Hayao.The Chuman (Hayao "Sam" and Toshiko) Papers documents the World War II experiences of Hayao "Sam" and Toshiko Chuman, who were Kibei Nisei born in the United States but grew up and completed school in Japan, and then returned to the U.S. prior to the war. It chronicles the Chuman's incarceration from the Santa Anita Assembly Center, through Jerome, Rohwer, Tule Lake camps, and the Santa Fe and Crystal City internment camps as well as their struggle for restoring their U.S. citizenships in the 1960s. The digital collection consists of mostly textual material, including correspondence, affidavits, incarceration camp records, lease agreements, financial documents, receipts, pamphlets, and booklets
Letter from Wayne M. Collins to Toshiko Chuman, June 14, 1957
No full textA letter from Wayne M. Collins to Toshiko Chuman (nee Nakamura) regarding a personal questionnaire for her to fill out so Wayne could fill out a new affidavit to send to the Department of Justice in an attempt to regain her U.S. citizenship.The Chuman (Hayao "Sam" and Toshiko) Papers documents the World War II experiences of Hayao "Sam" and Toshiko Chuman, who were Kibei Nisei born in the United States but grew up and completed school in Japan, and then returned to the U.S. prior to the war. It chronicles the Chuman's incarceration from the Santa Anita Assembly Center, through Jerome, Rohwer, Tule Lake camps, and the Santa Fe and Crystal City internment camps as well as their struggle for restoring their U.S. citizenships in the 1960s. The digital collection consists of mostly textual material, including correspondence, affidavits, incarceration camp records, lease agreements, financial documents, receipts, pamphlets, and booklets
Brigadier General Anthony Wayne
No full textPortrait of Brigadier General Wayne, facing right. Includes facsimile of Wayne\u27s signature.https://egrove.olemiss.edu/skipwith/1018/thumbnail.jp
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