California Current Ecosystem LTER

Size Fractionated Chlorophyll (CalCOFI Cruise)

Title
Size fractionation for total Chl a within the surface layer and calculated size distribution of total Chl a from discrete bottle samples from CCE-CalCOFI Augmented Cruises in the California Current System, 2004 - 2021 (ongoing).

Abstract
Water for size fractionation of chlorophyll a is sampled from ~10m depth (surface layer) on Line 83 and 87, with scattered inshore stations within the CalCOFI and SCCOOS stations located in the CCE study area. The size distribution of total chlorophyll a is determined by filtering water though filters of differing pore sizes. These are then extracted in acetone and analyzed fluorometrically with Turner Designs 10-AU Fluorometer on CalCOFI cruises (since 2006, ongoing). Chlorophyll a and taxon-specific pigments (chlorophylls and carotenoids) are qualitatively and quantitatively characterized in the lab onshore by several size fractions (< 1µm to > 20µm) utilizing High Performance Liquid Chromatography (HPLC) analysis. The samples analyzed within the CCE region are used to develop a metric for phytoplankton community structure that can be used to monitor its state and changes thereof over time.

Keywords
measurements, chlorophyll a, phytoplankton, seawater, depth

LTER Data System Record
http://dx.doi.org/10.6073/pasta/8ebed2a2ac22a27b23e7ba98f10dcbb4
Projects
California Current Ecosystem LTER

Creators
Goericke, Ralf (rgoericke@ucsd.edu)

Contact
CCE LTER Information Manager (ccelter.im@gmail.com)

Data

table SizeFractionatedChlorophyll
Main data table for dataset
Rows: 1981
Columns: 19
View / Download

Methods


General Methods
Size fractions for total Chl a were processed by filtering a known volume of seawater (0.10 to 0.25 L), thru 5 different filter pore sizes. Each filter type, Whatman GF/F; 1, 3 and 8 µM nucleopore filter; and 20µM Nitex filter, was sampled in triplicate. Filters were extracted in 7.0 mls of 90% acetone and stored in the dark at -18°C for approximately 24 hours. Samples were thawed in the dark until reaching room temperature and then analyzed on a Turner Designs 10-AU Fluorometer. Chlorophyll a was calculated from fluorescence (et al). Size fractionation samples were analyzed in the field. Pre and post cruise fluorometer calibrations, chlorophyll a (Sigma Cat#C6144), were acquired from the CalCOFI group and averaged

References


Goericke, R., The Size Structure of Marine Phytoplankton — What Are the Rules?. CalCOFI Reports, 52, 198-204, 2011. CCE LTER Contribution #0214.