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| Johnson, D. Demcey; Nganje, William E.. |
| DON is a toxic byproduct of fusarium head blight (FHB), a fungal disease of small grains. Beginning in 1993, a prolonged outbreak of FHB occurred in the Upper Midwest, the traditional source of most six-rowed malting barley produced in the United States. Price discounts associated with DON in barley have been significant. This paper has two objectives. The first is to estimate the impact of DON on the value of malting barley grown in the Upper Midwest. Using crop quality data, we use a linear programming model to derive optimal blends of barley supplies, given discount schedules and the distribution of quality factors. The premise is that blending activities, on a regional scale, allow a larger fraction of the crop to be sold as malting. The second... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Barley; Malt; DON; Fusarium head blight; Grain quality; Blending; Production Economics. |
| Ano: 2000 |
URL: http://purl.umn.edu/23103 |
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| Berg, Gm; Balode, M; Purina, I; Bekere, S; Bechemin, Christian; Maestrini, Serge. |
| Trends in nitrogen utilization, determined with N-15-labeled substrates, were related to blooms of distinct phytoplankton groups in the Gulf of Riga, Baltic Sea, during May, June and July 1999. The dominant phytoplankton groups included diatoms, cryptophytes, dinoflagellates, and filamentous cyanobacteria. As the water column became progressively more stratified over the growing season, diatoms comprised a smaller proportion of the total phytoplankton assemblage and almost disappeared by late summer. Their disappearance correlated with undetectable surface-water nitrate concentrations and low nitrate uptake rates (5 to 8% of total nitrogen uptake). Diatoms were the only phytoplankton group significantly associated with the uptake of oxidized nitrogen... |
| Tipo: Text |
Palavras-chave: Nitrogen uptake; DON; Nitrate; Diatoms; Cyanobacteria; Cryptophytes; Baltic Sea; Gulf of Riga. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00000/10207/7595.pdf |
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| Purvina, S; Béchemin, Christian; Balode, M; Verite, Celine; Arnaud, Christophe; Maestrini, Serge Y. |
| The use of riverine dissolved organic matter by the heterotrophic bacteria associated with a culture of the cyanobacterium Microcystis aeruginosa and release of simple nitrogen compounds were studied in an experimental series. Bacteria reduced the bulk of dissolved organic nitrogen (DON) by half, but when associated with M. aeruginosa, DON was excreted and its concentration rose by 13%. During the stationary growth phase bacteria released ammonium, doubling the concentration of ammonia as well as of nitrates. Bacteria associated with M. aeruginosa consumed riverine DON and joined the ammonification and nitrification process, supplying cyanobacteria with simple nitrogen compounds. |
| Tipo: Text |
Palavras-chave: Microcystis aeruginosa; Heterotrophic bacteria; DOM; DON; Nitrates; Ammonia. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00353/46408/46122.pdf |
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| Zilius, Mindaugas; De Wit, Rutger; Bartoli, Marco. |
| Sedimentation of pelagic cyanobacteria in dystrophic freshwater and oligohaline lagoons results in large inputs of labile organic matter (OM) to the benthos. We used an experimental approach to study the short-term impact of such phenomena on the benthic microbial community metabolism and on the nitrogen (N) fluxes across the sediment-water interface. We hypothesized an increase of respiratory activity, including N loss via denitrification and its recycling to the water column. Our results show that the incorporation within sediments of the settled bloom increases benthic bacterial activities. This is coupled to large DON and NH4+ effluxes, and to a comparatively smaller increase of N-2 production, while no significant effects were detected for the benthic... |
| Tipo: Text |
Palavras-chave: Cyanobacteria; Organic matter; Sediments; Benthic metabolism; DON; Denitrification. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00354/46504/74457.pdf |
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