The Sea-Bird Electronic Carousel Water Sampler (SBE 32) uses an electromagnetically activated lanyard release system to close 24 ten-liter plastic (PVC) bottles equipped with epoxy-coated springs and Viton O-rings. Each cast typically samples ~20 depths to a maximum sampling depth of 525 meters, bottom depth permitting. Four deeper CTD casts are performed at sta 90.90 (3500m), 80.90 (3500m), Santa Monica Basin (770m), & Santa Barbara Basin (570m). Some stations have multiple bottles tripped at the same depth to provide additional water for ancillary measurements. The bottle sample depths are based on the chlorophyll maximum & mixed layer depths profiled during the CTD downcast. Distributing the higher resolution, 10m bottle spacing around the chl max. Salinity, oxygen, and nutrients analyses are done at-sea for all depths sampled. Chlorophyll-a and phaeopigments are also measured at-sea on samples from the upper 200 meters, bottom depth permitting.
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On each station, seawater salinity samples of ~225 mL are drawn from all CTD-rosette bottles closed during the cast. A Guildline Instruments Portasal™ Salinometer (8410A) measures the seawater sample conductivity precisely, comparing it to a reference seawater standard. From these comparisons, salinities are calculated and logged using Windows-PC based software that averages data that meet replicate criteria. Concurrent with the water sampling, a Sea-Bird Electronics CTD equipped with dual conductivity meters profiles in situ data. Data processing software is then used to compare the bottle salts to in situ CTD measurements. These are used to confirm bottle closures at target depths, monitor CTD sensor performance, and helps select the best salinity data for future comparison and publication.
Complete methods of salinity determination can be found here.
Last Updated on Wednesday, 26 September 2012 13:30
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The phytoplankton macro nutrients nitrate, nitrite, silicate, phosphate and ammonium are analyzed in seawater using a colorimetric assay in which light absorbance is measured versus known standards. To analyze for nutrients a Seal Analytical continuous-flow AutoAnalyzer 3 (AA3) is used. After each run, the charts are reviewed for any problems, any blank is subtracted, and final concentrations (micro moles/liter) are calculated.
Complete methods for nutrient determination can be found here.
Primary productivity samples are taken each day shortly before local apparent noon (LAN). Primary production is estimated from 14C uptake using a simulated in situ technique. Light penetration is estimated from the Secchi depth (assuming that the 1% light level is three times the Secchi depth). The depths with ambient light intensities corresponding to light levels simulated by the on-deck incubators are identified and sampled on the rosette upcast. Occasionally an extra bottle or two are tripped in addition to the usual 20 levels sampled in the combined rosette-productivity cast in order to maintain the normal sampling depth resolution. Triplicate samples (two light and one dark control) are drawn from each productivity sample depth into 250 ml polycarbonate incubation bottles.
Complete methods for primary productivity determination can be found here.
Last Updated on Monday, 09 May 2011 14:22
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CCE LTER analyzes and determins total organic carbon (TOC) and total nitrogen (TN) in sea water, expressed as micromoles of carbon (nitrogen) per liter of sea water. TOC (<200 µmol·L-1) includes both dissolved and particulate organic carbon (DOC and POC, respectively). TN (<50 µmol·L-1) includes particulate and dissolved organic nitrogen as well as dissolved inorganic nitrogen species. The instruments employed are from the Aluwihare Laboratory at the Scripps Institution of Oceanography, and whenever possible, protocols closely follow those used by Jonathan Sharp (U. of Delware), Craig Carlson (U. of California, Santa Barbara) and Dennis Hansell (RMSAS). SIO has the Shimadzu TOC-VSN, normal sensitivity, with TN unit.
Complete methods of TOC and TN determination can be found here.
Last Updated on Wednesday, 11 May 2011 11:49
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CCE-LTER samples picophytoplankton populations and non-pigmented prokaryotes within the California Current Ecosystem (CCE) are fixed in the field by the addition of paraformaldehyde and, in the laboratory, stained with Hoechst 33342 (a DNA specific dye). The cells are enumerated by an Altra flow cytometer and converted to biomass estimates
Complete methods for picoplankton and bacteria abundance and biomass determination can be found here.
CCE-LTER uses a high-performance liquid chromatographic (HPLC) method with a reverse phase C8 column to measure concentrations of chlorophylls and carotenoids in samples of particulate matter from the California Current Ecosystem (CCE). Concentrations of chlorophyll a are used as a proxy for phytoplankton biomass and concentrations of other taxon-specific pigments are used to determine contributions of phytoplankton taxa to total phytoplankton biomass.
Complete methods for taxon-specific phyto-pigments determination can be found here.
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The amount of dissolved oxygen in seawater is measured using the Carpenter modification of the Winkler method. Carpenters modification (1965) was designed to increase the accuracy of the original method devised by Winkler in 1889. Using Carpenters modification, the significant loss of iodine is reduced and air oxidation of iodide is minimized. Rather than using the visible color of the iodine-starch complex as an indicator of the titration end-point, we use an automated titrator that measures the absorption of ultraviolet light by the tri-iodide ion, which is centered at a wavelength of 350 nm.
Complete methods of dissolved oxygen determination can be found here.
Last Updated on Monday, 09 May 2011 14:21
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Chlorophyll a is cold-extracted in a 90% acetone solution for ~24 hours. Chlorophyll and phaeopigments are then measured fluorometrically using an acidification technique. The method used today is based on those developed by Yentsch and Menzel (1963), Holm-Hansen et al. (1965) and Lorenzen (1967). Note that concentrations of 'phaeopigments' are not a good measure of Chl a degradation products present in the sample since Chl b present in the sample will be measured as 'phaeopigments'.
Complete methods of chlorophyll a determination can be found here.
The CalCOFI group collects samples for the characterization of the inorganic carbon system at selected locations along the cruise track. Total inorganic carbon and alkalinity are measured which allows the calculation of pH and pCO2. The objectives of these measurements are: first, the long-term characterization of the inorganic carbon system and its response to changing ocean climate, and second, measurements of pH in the coastal zone in order to monitor the impact of 'corrosive' waters on benthic ecosystems in the Southern California Bight.
Last Updated on Wednesday, 26 September 2012 13:48
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CCE LTER measures particulate organic carbon (POC) and nitrogen (PON) by high-temperature combustion. Samples analyzed within the California Current Ecosystem constrain the mean C:N ratio of small particulates and by difference relative to measured living biomass, the biomass of suspended detritus.
Complete methods of POC and PON determination can be found here.
CCE-LTER determines the size distribution of total chlorophyll a by filtering water though filters of differing pore sizes, extracting these in acetone and analyzing fluorometrically. Using size fractionation of chlorophyll a and taxon-specific pigments (chlorophylls and carotenoids) from HPLC analysis, the samples analyzed within the California Current Ecosystem are used to develop a metric for phytoplankton community structure that can be used to monitor its state and changes thereof over time.
Complete methods for chlorophyll a size fractionation can be found here.
CCE-LTER asseses the microbial community assemblages of the California Current ecosystem (CCE) for abundance and biomass using high-throughput digital epifluorescence microscopy. Samples to estimate the nano- and microplankton (0.2-2.0-µm and 2.0-20-µm size, respectively) are collected, preserved, stained, and filtered onto a membrane filter and mounted on a glass microscope slide in the field. Slides are then frozen at -80°C for subsequent imaging and analysis in the laboratory onshore.
Complete methods for microbial community assemblage assessment can be found here.
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