A quantitative study of the bottom fauna in some Utah Streams Variously Affected by Erosion

journal articleFloods and cloudbursts in the Intermountain region of western United States cause considerable damage to watersheds and streams. Because of steep gradients these torrential waters remove vast quantities of debris, stones, gravel and soil from the stream beds. It follows that, with the removal of materials from a stream bottom, the flora and fauna would also be affected. To determine the effects of flood conditions upon bottom fauna and the subsequent reestablishment of these forms is the purpose of this study

Production of cobalt binding ligands in a Synechococcus feature at the Costa Rica upwelling dome

Author Posting. © American Society of Limnology and Oceanography, 2005. This is the author's version of the work. It is posted here by permission of American Society of Limnology and Oceanography for personal use, not for redistribution. The definitive version was published in Limnology and Oceanography 50 (2005): 279-290.The Costa Rica upwelling dome (CRD; ~8.67ºN and 90.6ºW) was characterized chemically for cobalt and nickel abundances and speciation, and biologically using cyanobacterial abundances and phylogeny. Total dissolved cobalt was 93 pmol L-1at 90 m depth and decreased in surface waters to 45 pmol L-1 at 10 m. Cobalt was 40% labile at 90 m, but was completely complexed by strong ligands at 10 m. A surface transect out of the dome showed decreasing total dissolved cobalt from 57 pmol L-1 to 12 pmol L-1. Detection window studies showed that natural cobalt ligand complexes have conditional stability constants greater than 1016.8, and that competition with nickel did not release cobalt bound to organic complexes, consistent with natural cobalt ligands being Co(III)-complexes. Synechococcus cell densities at the CRD are among the highest reported in nature, varying between 1.2 x 106 to 3.7 x 106 cells ml-1. Phylogenetic analysis using the 16S-23S rDNA internally transcribed spacer showed the majority of clones were related to Synechococcus strain MIT S9220, while the remaining subset form a novel group within the marine Synechococcus lineage. In a bottle incubation experiment chlorophyll increased with cobalt and iron additions relative to each element alone and the unamended control treatment. Cobalt speciation analysis of incubation experiments revealed large quantities of strong cobalt ligand complexes in the cobalt addition treatments (401 pmol L-1), whereas cobalt added to a 0.2 mm filtered control remained predominantly labile (387 pmol L-1), demonstrating that the Synechococcus-dominated community is a source of strong cobalt ligands.This research was funded by NSF OCE-9618729, OCE-0327225, and OCE-0220826

Total dissolved copper, estimates of free Cu2+, ligand concentrations, and conditional stability constants from R/V Knorr KN199-04, KN204-01, subtropical North Atlantic Ocean from 2010-2011 (U.S. GEOTRACES NAT project)

Dataset: GT10-11 - Cu SpeciationThis dataset includes total dissolved copper, estimates of free Cu2+, ligand concentrations, and conditional stability constants from R/V Knorr cruises KN199-04 and KN204-01 in the subtropical North Atlantic Ocean from 2010-2011 (U.S. GEOTRACES NAT project) For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/3845NSF Division of Ocean Sciences (NSF OCE) OCE-092738

The flux of iron and iron isotopes from San Pedro Basin sediments

Iron is an important nutrient in the ocean, but the different sources and sinks of iron are not well constrained. Here, we use measurements of Fe concentration and Fe stable isotope ratios to evaluate the importance of reducing continental margins as a source of Fe to the open ocean. Dissolved iron concentration ([Fe]) and iron stable isotope ratios (δ^(56)Fe) were measured in the San Pedro and Santa Barbara basins. Dissolved δ^(56)Fe ranges from −1.82‰ to 0.00‰ in the San Pedro Basin and from −3.45‰ to −0.29‰ in the Santa Barbara Basin, and in both basins the lowest δ^(56)Fe values and highest Fe concentrations are found at the bottom of the basin reflecting the input of isotopically light Fe from reducing sediment porewaters. In the San Pedro Basin, we are also able to fingerprint an advective source of Fe from shallow continental shelves next to the basin and the atmospheric deposition of Fe into surface waters. A one-dimensional model of the Fe isotope cycle has been constructed for the deep silled San Pedro Basin. By fitting model output to data, values of several important iron cycle parameters are predicted including a flux of Fe from sediment porewaters into the water column of 0.32–1.14 μmol m^(−2) d^(−1), a first-order dissolved Fe precipitation rate constant of 0.0018–0.0053 d^(−1), a flux δ56Fe of −2.4‰, and an isotope effect for Fe precipitation of Δδ^(56)Fe_(particulate-dissolved) = −0.8‰. Applying our model-predicted Fe cycle parameters to the global ocean suggests that continental margins contribute 4–12% of world ocean dissolved Fe and make the ocean’s Fe lighter by −0.08‰ to −0.26‰. The dramatically negative δ^(56)Fe signature seen in the water column of the San Pedro and Santa Barbara basins demonstrate the utility of Fe isotopes as a tracer for continental margin Fe input from reducing sediments to the oceans, while the isotopic fractionation observed during loss of Fe from the dissolved phase suggests that this signature will be modified by subsequent reactions. Our modeling provides an initial framework for testing how these signals are transmitted into the open ocean

Examining how the Dark Triad moderates the relationship between workplace victimization and workplace behavior

This study will examine the relationship between workplace victimization and workplace behavior. Furthermore, this study will examine how the Dark Triad of personality affects that relationship. The study will be conducted as a Masters’ Thesis at Middle Tennessee State University. We propose that the there is a positive relationship between workplace victimization and counterproductive work behaviors (CWB) and a negative relationship between workplace victimization and occupational citizenship behaviors (OCB). We also propose that the Dark Triad (narcissism, Machiavellianism, and psychopathy) each positively moderate the relationship between workplace victimization and CWB. Data on each of these constructs will be collected from participants through Amazon’s Mechanical Turk. This study is intended to help gain an understanding of the range of negative effects that workplace victimization can have on both victims and organizations at large. This study will allow researchers and practitioners alike to understand the negative consequences of workplace mistreatment; also, it may motivate organizations to establish policies to protect their employees from harm

e-Book on plant virus infection—a cell biology perspective

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Meridional Survey of the Central Pacific Reveals Iodide Accumulation in Equatorial Surface Waters and Benthic Sources in the Abyssal Plain

The distributions of iodate and iodide were measured along the GEOTRACES GP15 meridional transect at 152°W from the shelf of Alaska to Papeete, Tahiti. The transect included oxygenated waters near the shelf of Alaska, the full water column in the central basin in the North Pacific Basin, the upper water column spanning across seasonally mixed regimes in the north, oligotrophic regimes in the central gyre, and the equatorial upwelling. Iodide concentrations are highest in the permanently stratified tropical mixed layers, which reflect accumulation due to light-dependent biological processes, and decline rapidly below the euphotic zone. Vertical mixing coefficients (Kz), derived from complementary 7Be data, enabled iodide oxidation rates to be estimated at two stations. Iodide half-lives of 3–4 years show the importance of seasonal mixing processes in explaining north-south differences in the transect, and also contribute to the decrease in iodide concentrations with depth below the mixed layer. These estimated half-lives are consistent with a recent global iodine model. No evidence was found for significant inputs of iodine from the Alaskan continental margin, but there is a significant enrichment of iodide in bottom waters overlying deep sea sediments from the interior of the basin