Integrated chlorophyll-a
Chlorophyll-a integrated over the top 200 m (or the cast bottom): the sum of the 1 m bins
mg/m²key chl_integratedno NERC concept says exactly thisseries chl_integrated
one value per cast One value per cast. This measurement is worked out once for each cast rather than read at every depth, so it has no depth profile and no anomaly against a normal; its values are rows of sample_measurement, not of obs_env.
CalCOFI holds 9,171 values of it from 9,171 sampling events in one dataset, 1993–2026, one per cast.R Every phytoplankter carries chlorophyll-a, so adding it up through the water column gives the plant life under each square metre of sea, a number that does not depend on which depth the peak sits at.C
- 9,171
- values
- 0
- flagged
- 1993–2026
- years
- 1
- dataset
- every month
- months
Measured in
1 dataset
i
One row per series, one cell per year, darker with more values — the same strip the front
door draws per dataset and a species page draws per taxon. Each row is one dataset's own
measurement_type; the label is written once, in the title above.
i
One row per series, one cell per year, darker with more values — the same strip the front door draws per dataset and a species page draws per taxon. Each row is one dataset's own measurement_type; the label is written once, in the title above.
-
series
chl_integrated· source columnest_chlorophyll_a_sta_corrone value per cast no flag at this grain no P01 concept
Explorerdb-queryThis page as JSON R · Python · Parquet
Every way in 6 ways · Parquet · R · Python · JSON
Read from measurements.json of release v2026.10.21, written at release by calcofi4db::build_measurements_catalog() beside taxa.json. The catalog's index is /measurements/; the JSON-LD on this page is a schema.org/DefinedTerm in the NERC P01 term set with a PropertyValue per series.
Explorerdb-querySELECT * FROM read_json('…/v2026.10.21/catalog.json')
-- objects[] WHERE table = 'sample_measurement'
-- then filter the rows:
-- measurement_type IN ('chl_integrated')library(calcofi4r)
con <- cc_get_db() # the promoted release
tbl(con, "sample_measurement") |> filter(measurement_type %in% c("chl_integrated"))import calcofi4py as cc
con = cc.cc_get_db()
con.sql("SELECT * FROM sample_measurement WHERE measurement_type IN ('chl_integrated')").df()The structure chlorophyll-a measured fluorometrically’s, standing in
RDKit 2026.03.6 from the ChEBI molfile, in the page’s ink · CC BY 4.0. ChEBI’s roles are never shown.
How it is measured Computed from the CTD fluorometer profile (corrected to bottle chlorophyll-a)
Chlorophyll-a integrated through the water column: the station-corrected CTD profile summed over the top 200 m, or to the cast depth on a shallower station. (the record's own derivation (measurement_type.csv); questions Q02 (Rasmus Swalethorp, 2026-09-23))
- integrate the 1 m bins from the surface to 200 m or the cast bottom
Why it matters 4 ways to say it · EOV Phytoplankton biomass and diversity
the GOOS specification sheet for this Essential Ocean Variable lists it
other ways to say why · 3
- The sum runs from the surface to 200 m, or to the bottom of the cast on a shallower station, and chl_integrated_depth says how deep each one reached, so a cast that stopped short is not mistaken for a thin one. needs a citation before it can be the pick
- Wikipedia Primary production source
- Wikipedia Chlorophyll a is a specific form of chlorophyll used in oxygenic photosynthesis. It absorbs most energy from wavelengths of violet-blue and orange-red light. Chlorophyll a · CC BY-SA 4.0 · rev. 1373717553
Units and range mg/m² · 0 … 200,000 declared · 0 flagged
mg/m² (mg/m2 in metadata/measurement_type.csv)
details
- bounds
- The registry declares
0 … 200,000 mg/m²forchl_integrated; a value outside it is dropped at the ingest (drop_out_of_bounds()). - observed
- CTD Derived Products
chl_integrated0.9385 · median 36.27 · 984.2 mg/m² (5th–95th percentile 21.99–159.2) - flags
- CTD Derived Products
chl_integratedcarries no quality code at the release grain; qual_ok keeps all 9,171. - baseline
- A monthly climatology exists for this measurement (the release's climatology table: 1993–2013, dataset × station × the cruise's month × 10 m bin), so the Explorer can draw anomalies against it rather than values.
- derivation
- calcofi4db::ctd_integrate(z_max = 200, z_top_max = 5, method = 'sum'): the sum of the 1 m bins of est_chlorophyll_a_sta_corr (ug/L = mg/m3) from the surface to 200 m or the deepest good bin; the provider's CTD rule (Rasmus Swalethorp 2026-09-23, questions Q02); a bin missing inside the profile is interpolated, the shallowest bin is carried to the surface when it is no deeper than 5 m, else absent; chl_integrated_depth says how deep it reached
The familiar scale i
Bars are each series' 5th–95th percentile, the line its minimum to maximum, the ring its median;
the marks are metadata/measurement_scale.csv's, each hovering to its own source.
i
Bars are each series' 5th–95th percentile, the line its minimum to maximum, the ring its median;
the marks are metadata/measurement_scale.csv's, each hovering to its own source.
By month every month
By month i
Values per calendar month, one row per series: CalCOFI's quarterly cruises show as peaks in
the months the ships sail.
i
Values per calendar month, one row per series: CalCOFI's quarterly cruises show as peaks in the months the ships sail.
Cite the release, v2026.10.21
Cite the release; each dataset's own citation, licence and DOI are on its page — CTD Derived Products. The Explorer's Share → Cite writes it for the view you make.