Determination of nutrient salts by automatic methods both in seawater and brackish water: the phosphate blank

9 páginas, 2 tablas, 2 figurasThe main inconvenience in determining nutrients in seawater by automatic methods is simply solved: the preparation of a suitable blank which corrects the effect of the refractive index change on the recorded signal. Two procedures are proposed, one physical (a simple equation to estimate the effect) and the other chemical (removal of the dissolved phosphorus with ferric hydroxide).Support for this work came from CICYT (MAR88-0245 project) and Conselleria de Pesca de la Xunta de GaliciaPeer reviewe

Soziale Auswirkungen der technisch-organisatorischen Rationalisierung durch Einführung und Weiterentwicklung computergestützter Informations- und Verarbeitungssysteme: e. Fallstudie am Beisp. von kaufmänn. Arbeitsbereichen e. industriellen Großbetriebes zu d. Entwicklungstendenzen von Beschäftigung, Einkommensbedingungen, Qualifikationsanforderungen, psych. Belastungen u. Beanspruchungen sowie zu d. gewerkschaftl. Interessenvertretung

Knepel WK. Soziale Auswirkungen der technisch-organisatorischen Rationalisierung durch Einführung und Weiterentwicklung computergestützter Informations- und Verarbeitungssysteme: e. Fallstudie am Beisp. von kaufmänn. Arbeitsbereichen e. industriellen Großbetriebes zu d. Entwicklungstendenzen von Beschäftigung, Einkommensbedingungen, Qualifikationsanforderungen, psych. Belastungen u. Beanspruchungen sowie zu d. gewerkschaftl. Interessenvertretung. Bielefeld; 1984

Unexpected presence of the nitrogen‐fixing symbiotic cyanobacterium UCYN‐A in Monterey Bay, California

In the last decade, the known biogeography of nitrogen fixation in the ocean has been expanded to colder and nitrogen-rich coastal environments. The symbiotic nitrogen-fixing cyanobacteria group A (UCYN-A) has been revealed as one of the most abundant and widespread nitrogen-fixers, and includes several sublineages that live associated with genetically distinct but closely related prymnesiophyte hosts. The UCYN-A1 sublineage is associated with an open ocean picoplanktonic prymnesiophyte, whereas UCYN-A2 is associated with the coastal nanoplanktonic coccolithophore Braarudosphaera bigelowii, suggesting that different sublineages may be adapted to different environments. Here, we study the diversity of nifH genes present at the Santa Cruz Municipal Wharf in the Monterey Bay (MB), California, and report for the first time the presence of multiple UCYN-A sublineages, unexpectedly dominated by the UCYN-A2 sublineage. Sequence and quantitative PCR data over an 8-year time-series (2011-2018) showed a shift toward increasing UCYN-A2 abundances after 2013, and a marked seasonality for this sublineage which was present during summer-fall months, coinciding with the upwelling-relaxation period in the MB. Increased abundances corresponded to positive temperature anomalies in MB, and we discuss the possibility of a benthic life stage of the associated coccolithophore host to explain the seasonal pattern. The dominance of UCYN-A2 in coastal waters of the MB underscores the need to further explore the habitat preference of the different sublineages in order to provide additional support for the hypothesis that UCYN-A1 and UCYN-A2 sublineages are different ecotypes