Estimates of new and total productivity in central Long Island Sound from in situ measurements of nitrate and dissolved oxygen

Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Estuaries and Coasts 36 (2013): 74-97, doi:10.1007/s12237-012-9560-5.Biogeochemical cycles in estuaries are regulated by a diverse set of physical and biological variables that operate over a variety of time scales. Using in situ optical sensors, we conducted a high-frequency time-series study of several biogeochemical parameters at a mooring in central Long Island Sound from May to August 2010. During this period, we documented well-defined diel cycles in nitrate concentration that were correlated to dissolved oxygen, wind stress, tidal mixing, and irradiance. By filtering the data to separate the nitrate time series into various signal components, we estimated the amount of variation that could be ascribed to each process. Primary production and surface wind stress explained 59% and 19%, respectively, of the variation in nitrate concentrations. Less frequent physical forcings, including large-magnitude wind events and spring tides, served to decouple the relationship between oxygen, nitrate, and sunlight on about one-quarter of study days. Daytime nitrate minima and dissolved oxygen maxima occurred nearly simultaneously on the majority (> 80%) of days during the study period; both were strongly correlated with the daily peak in irradiance. Nighttime nitrate maxima reflected a pattern in which surface-layer stocks were depleted each afternoon and recharged the following night. Changes in nitrate concentrations were used to generate daily estimates of new primary production (182 ± 37 mg C m-2 d-1) and the f-ratio (0.25), i.e., the ratio of production based on nitrate to total production. These estimates, the first of their kind in Long Island Sound, were compared to values of community respiration, primary productivity, and net ecosystem metabolism, which were derived from in situ measurements of oxygen concentration. Daily averages of the three metabolic parameters were 1660 ± 431, 2080 ± 419, and 429 ± 203 mg C m-2 d-1, respectively. While the system remained weakly autotrophic over the duration of the study period, we observed very large day-to-day differences in the f-ratio and in the various metabolic parameters.This work was supported by the Yale Institute for Biospheric Studies, the Sounds Conservancy of the Quebec-Labrador Foundation, and the Yale School of Forestry and Environmental Studies Carpenter-Sperry Fund.2014-01-0

Preparation and Characterization of Activated Carbon Obtained from Plantain (Musa paradisiaca) Fruit Stem

Carbonization of carbon obtained from plantain (Musa paradisiaca) stem was achieved at a temperature of 400°C for one hour. The carbonized carbon was divided into two parts to be activated separately. The activated carbon CPPAC (carbonized plantain phosphoric acid activated carbon) and CPZAC (carbonized plantain zinc chloride activated carbon) were produced via the chemical activation process using H3PO4 and ZnCl2. Characterization of pH, bulk density, moisture content, ash content, volatile matter, iodine number, and oxygen functional group was conducted. When comparing the surface properties of both CPPAC and CPZAC with the untreated plantain carbon (UPC), it was observed that there existed significant differences in all properties with the exemption of carboxylic group for CPPAC and phenolic group for both CPPAC and CPZAC, thus signifying that a chemical transformation did occur. When comparing the results obtained from CPPAC to that of CPZAC, CPPAC was more preferable for adsorption due to its low bulk density, low ash content, and high iodine value, signifying thus that the activating agents both reacted differently with the plantain stem

Bleach Effectively in Removes the Stubborn Stains

Along with the development of science and technology, more and more types of manufactured goods produced to meet our needs we need to know that among these materials there are dangerous or toxic, therefore it is very important for us to know the type, nature, usefulness, as well as the dangers of every chemical that we use at home As we know, all kinds of objects that are around us are actual material, all material consists of chemicals but, in our daily lives we commonly use the term material instead of chemicals. Clothing that we use every day will be prone to stains so it is important to know how to remove stubborn stains on clothes. It would be very inconvenient if the clothes worn are dirty and not beautiful to the eye. There are many types of stains, ranging from dirty sweat, blood, residual makeup, black spots caused by fungus, to stains from the outside such as stains caused by rust, paint, oil, ink or spills of food and drinks. If you use the wrong method to remove these stains, it is not uncommon for us to find difficulties and can even be fatal as they get dirty. Each type of stain has a different treatment, depending on the nature of the stain. Bleach is now available as a solution to the problem of stains on these clothes