Estimated nitrate, cruise-corrected
Est. nitrate cruise-corrected
µmol/Lkey est_nitrate_cruise_corrP06 units UPOXseries est_nitrate_cruise_corr
CalCOFI holds 313,893 values of it from 4,774 sampling events in one dataset, 2004–2026, from the surface to 1,117 m. At 200–500 m it has fallen 1.50 per decade since 2005.R Nitrate is the fertiliser upwelling lifts into the light; the spring blooms, and the fisheries above them, run on it. At depth it has risen as oxygen fell, the fingerprint of changing source waters.C
- 313,893
- values
- 753
- flagged
i
753 of these 313,893 values (0.2 %) are flagged by their provider as questionable or bad. The Explorer, the climatology and its anomalies leave them out; do the same when you read the data yourself (cc_qual_ok_sql()in calcofi4r,qual_ok_sql()in calcofi4py). - 2004–2026
- years
- 1
- dataset
- 1–1,117 m
- depth
- 10 of 12
- 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
est_nitrate_cruise_corr· source columnest_no3_cruise_corr· flag columnest_no3_cruise_corr_qno P01 concept 753 flagged · 0.2 %
Explorera depth section vs normaldb-queryERDDAPThis page as JSON R · Python · Parquet
Every way in 8 ways · ERDDAP · Parquet · R · Python · JSON
Read from measurements.json of release v2026.11.05, 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.
ExplorerExplorer · a depth section vs normaldb-querySELECT * FROM read_json('…/v2026.11.05/catalog.json')
-- objects[] WHERE table = 'obs_env'
-- AND partition_value = 'est_nitrate_cruise_corr'library(calcofi4r)
con <- cc_get_db() # the promoted release
tbl(con, "obs_env") |> filter(measurement_type %in% c("est_nitrate_cruise_corr"))import calcofi4py as cc
con = cc.cc_get_db()
con.sql("SELECT * FROM obs_env WHERE measurement_type IN ('est_nitrate_cruise_corr')").df()The structure nitrate concentration’s, standing in
ChEBI: “A nitrogen oxoanion formed by loss of a proton from nitric acid. Principal species present at pH 7.3.” · 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 Satlantic ISUS ultraviolet nitrate sensor on the CTD
The ISUS in-situ ultraviolet nitrate sensor's voltage is converted to nitrate by a per-cast regression fitted against that cast's own bottle nitrates (about 20, fliers omitted) from 1 m bin-averaged sensor data; a 500 m cast with ten or more bottles is required, so shallow or bottle-poor casts carry no estimate by design. (the record's own derivation for est_nitrate_sta_corr (measurement_type.csv), corroborated by the CTD FAQ's bottle-correction description)
the record's own derivation for est_nitrate_sta_corr (measurement_type.csv), corroborated by the CTD FAQ's bottle-correction description on calcofi.org ↗Why it matters 7 ways to say it · EOV Nutrients
the GOOS specification sheet for this Essential Ocean Variable lists it, and asks
GOOS asks
- How do the eutrophication and pollution impact ocean productivity and water quality?
- Is the biomass of the ocean changing?
GOOS specification sheet ↗ · quoted, not copied
other ways to say why · 6
- A sensor on the CTD reads nitrate every metre where the bottles sample a couple of dozen depths, so it resolves the nitracline the bottles straddle. needs a citation before it can be the pick
- Nitrate at the surface is a fingerprint of recent upwelling: where it is high, cold deep water has just arrived and a bloom follows. needs a citation before it can be the pick
- GOOS asks How do the eutrophication and pollution impact ocean productivity and water quality? source
- GOOS asks Is the biomass of the ocean changing? source
- Wikipedia Upwelling source
- Wikipedia Nitrate is a polyatomic ion with the chemical formula NO3−. Salts containing this ion are called nitrates. Nitrate · CC BY-SA 4.0 · rev. 1378622700
The record’s own history 6 depth bands against the 1993–2013 normal
Each year against the normal i
Deeper than the climatology reaches: 222 values at 1000–2000 m have no
normal to depart from, because the release’s climatology stops at its
deepest built bin. Carrying it to the bottom is one argument of
build_climatology() and puts these bands on the page too.
i
Deeper than the climatology reaches: 222 values at 1000–2000 m have no
normal to depart from, because the release’s climatology stops at its
deepest built bin. Carrying it to the bottom is one argument of
build_climatology() and puts these bands on the page too.
Units and range µmol/L · 0 … 200 declared · 753 flagged
µmol/L (umol/L in metadata/measurement_type.csv) · P06 units UPOX
details
- bounds
- The registry declares
0 … 200 µmol/Lforest_nitrate_cruise_corr; a value outside it is dropped at the ingest (drop_out_of_bounds()). - observed
- CTD Cast Files
est_nitrate_cruise_corr0 · median 26.48 · 120.2 µmol/L (5th–95th percentile 0–40.31) - flags
- CTD Cast Files
est_nitrate_cruise_correst_no3_cruise_corr_qon 1,237 of 313,893 rows:4484 ·8657 ·996; qual_ok keeps 313,140. The codes are this dataset's own vocabulary, uninterpreted. - 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
- ISUS nitrate sensor voltage converted to nitrate by regression against bottle nitrate. Bottle-corrected with ONE regression per cruise, fitted from 4-second-averaged sensor data against all the cruise's bottles (n ~ 1400, fliers omitted).
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 depth · by month 1–1,117 m · 10 of 12 months
By depth i
Values per depth band at the release grain, one thin bar per series. The bands are the
record's own (0-10 … 2000+ m).
i
Values per depth band at the release grain, one thin bar per series. The bands are the record's own (0-10 … 2000+ m).
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, v2026.11.05
Cite the release; each dataset's own citation, licence and DOI are on its page — CTD Cast Files. The Explorer's Share → Cite writes it for the view you make.