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Series 2: CO2 Aggregation Experiment - Aggregate Sinking Velocity
The sinking velocities of ten randomly selected aggregates from each tank were measured in a 2-liter cylindrical settling column that was 8 cm wide in a temperature constant room . Each aggregate was allowed to sink out of the wide bore pipette into the settling column. The duration of the descent of the aggregate over a distance of 20 cm, from 6 cm below the surface to 6 cm above the bottom, was monitored using a stop watch. Just before this, the length and width of each aggregate were measured to the nearest mm under a dissecting scope. Aggregate volume was calculated based on an ellipsoid shape, assuming that width and depth were identical.
Reference: Passow, U., Rocha, C.L.D.L., Fairfield, C., Schmidt, K., 2014. Aggregation as a function of pCO2 and mineral particles. Limnology and Oceanography 59 (2), 532-547.
See: Series 2: CO2 Aggregation Experiment - Methods
BCO-DMO Note: Instruments listed apply to all phases of the Series 2 data. Not just the experiment(s) represented in the individual dataset.
BCO-DMO Processing Notes Original file: "CO2 Aggregation ExperimentUtaApril2011-4.xlsx" contributed by Uta Passow Sheet: "Agg sinking velocity" - Approx Lat/Lon of Passow Lab appended to enable data discovery in MapServer - "nd" (no data) inserted into blank cells - Parameter names edited to conform to BCO-DMO parameter naming conventions
The settled aggregates were then photographed for image analysis of their size and total number.
A type of underwater camera system used for photographing aggregates in tanks or other containers.
TA was calculated from linear Gran plots (Gran 1952) after duplicate potentiometric titration (Brewer et al. 1986) using a TitroLine alpha plus (Schott Instruments, Mainz, Germany). Average precision was ± 5 μmol kg-1. Certified Reference Materials (CRMs, Batch No. 54) supplied by A. Dickson (Scripps Institution of Oceanography, USA) was used as a control.
Instruments that incrementally add quantified aliquots of a reagent to a sample until the end-point of a chemical reaction is reached.
The filters for POC and PON were fumed to remove inorganic carbon and analyzed at the Analytical Laboratory of the Marine Science Institute at UCSB using an elemental analyzer (CEC 44OHA by Control Equipment Corp).
A CHN Elemental Analyzer is used for the determination of carbon, hydrogen, and nitrogen content in organic and other types of materials, including solids, liquids, volatile, and viscous samples.
Salinity was determined from TA samples using a conductivity instrument (3100 Yellow Springs Instruments)
Conductivity Meter - An electrical conductivity meter (EC meter) measures the electrical conductivity in a solution. Commonly used in hydroponics, aquaculture and freshwater systems to monitor the amount of nutrients, salts or impurities in the water.
Concentrations of NO3+NO2, PO4 and Si(OH)4 in the initial phytoplankton-detritus mixture were measured by simultaneous flow injection analysis (QuickCem 8000, Lachat Instruments) in the Analytical Laboratory of the Marine Science Institute at UCSB from pre-filtered frozen samples.
An instrument that performs flow injection analysis. Flow injection analysis (FIA) is an approach to chemical analysis that is accomplished by injecting a plug of sample into a flowing carrier stream. FIA is an automated method in which a sample is injected into a continuous flow of a carrier solution that mixes with other continuously flowing solutions before reaching a detector. Precision is dramatically increased when FIA is used instead of manual injections and as a result very specific FIA systems have been developed for a wide array of analytical techniques.
A device on a ship or in the laboratory that holds water samples under controlled conditions of temperature and possibly illumination.
The length and width of each aggregate were measured to the nearest mm under a dissecting scope.
Instruments that generate enlarged images of samples using the phenomena of reflection and absorption of visible light. Includes conventional and inverted instruments. Also called a "light microscope".
DIC was measured colorimetrically in duplicate with a TRAACS CS800 autoanalyzer (Seal, Mequon, USA) with a precision of ± 5 μmol kg-1. CRM (Batch No. 54) supplied by A. Dickson was used as a calibration (see for methodological details).
Nutrient Autoanalyzer is a generic term used when specific type, make and model were not specified. In general, a Nutrient Autoanalyzer is an automated flow-thru system for doing nutrient analysis (nitrate, ammonium, orthophosphate, and silicate) on seawater samples.
Roller tanks experiments: 14 cylindrical five-liter roller tanks/ treatments rotating at 1 rpm encompassing three acidification scenarios and 5 concentrations of the clay illite incubated at 14oC in continuous darkness for 44 to 48 hours. Solid body rotation was established within three hours.
Rolling tanks, which keep particles in suspension, thus simulating aggregate formation in situ.
Marine snow experiments are conducted in roller tanks, which turn continuously, keeping marine snow in suspension. It is important for marine snow not to touch surfaces. The rolling tanks, which keep particles in suspension, thus simulate aggregate formation in situ. Marine snow formation due to different types of oil was tested. Some treatments are easily identifiable as containing oil by their color (middle). UCSB, CA 2012.
The filtered samples were immediately frozen at -20°C and later analyzed via high temperature combustion on a modified Shimadzu TOC-V analyzers in the Carlson lab at UCSB.
A Shimadzu TOC-V Analyzer measures DOC by high temperature combustion method.
The samples for pHT were collected bubble free in 20-ml scintillation vials and measured within 1-2 hours of sampling with a spectrophotometer (Genesys 10SVIS) equipped with a single cell Peltier (SPG1A, both Thermo Scientific) using the indicator dye m-cresol purple (Sigma-Aldrich) at a constant temperature of 25oC.
An instrument used to measure the relative absorption of electromagnetic radiation of different wavelengths in the near infra-red, visible and ultraviolet wavebands by samples.
TF CO2 conditions
Volume of concentrated suspension of clay (illite) additions
Equivalent Spherical Diameter
Aggregate sinking velocity
Lab Id - Lab identifier where experiments were conducted
Approximate Latitude Position of Lab; South is negative
Approximate Longitude Position of Lab; West is negative
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