Nitrite
Nitrite concentration
µmol/Lkey nitriteNERC P01 NTRIZZXXP06 units UPOXseries nitrite
CalCOFI holds 364,442 values of it from 14,497 sampling events in one dataset, 1959–2021, from the surface to 5,351 m. At 10–50 m it has risen 0.01 per decade since 1984.R Nitrite sits between ammonium and nitrate in the nitrogen cycle and almost nowhere else, so its thin peak at the bottom of the sunlit layer marks where that cycle is turning over.C
- 364,442
- values
- 18,189
- flagged
i
18,189 of these 364,442 values (5.0 %) 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). - 1959–2021
- years
- 1
- dataset
- 0–5,351 m
- depth
- 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
nitrite· source columnno2u_m· flag columnno2q18,189 flagged · 5.0 %
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 v2026.10.21, 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.
ExplorerExplorer · a depth section vs normaldb-querySELECT * FROM read_json('…/v2026.10.21/catalog.json')
-- objects[] WHERE table = 'obs_env'
-- AND partition_value = 'nitrite'library(calcofi4r)
con <- cc_get_db() # the promoted release
tbl(con, "obs_env") |> filter(measurement_type %in% c("nitrite"))import calcofi4py as cc
con = cc.cc_get_db()
con.sql("SELECT * FROM obs_env WHERE measurement_type IN ('nitrite')").df()The structure NO2− nitrite
ChEBI: “The nitrogen oxoanion formed by loss of a proton from nitrous acid.” · 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 Seal Analytical continuous-flow AutoAnalyzer 3 (AA3) at 520 nm
The same azo-dye method as nitrate, but without the cadmium reduction column, so only the sample's own nitrite is coupled and read. (calcofi.org Bottle sampling methods)
- NO2- + sulfanilamide + NED -> red azo dye
- absorbance read at 520 nm
Why it matters 4 ways to say it · EOV Nutrients
the GOOS specification sheet for this Essential Ocean Variable lists it, and asks
GOOS asks
- Is the biomass of the ocean changing?
GOOS specification sheet ↗ · quoted, not copied
other ways to say why · 3
- Because nitrite is an intermediate, a high value is a statement about rates rather than about stock. needs a citation before it can be the pick
- GOOS asks Is the biomass of the ocean changing? source
- Wikipedia The nitrite ion has the chemical formula NO2–. Nitrite (mostly sodium nitrite) is widely used throughout chemical and pharmaceutical industries. Nitrite · CC BY-SA 4.0 · rev. 1376627975
The record’s own history 6 depth bands against the 1993–2013 normal
Each year against the normal i
Deeper than the climatology reaches: 1,470 values at 1000–2000 m, 615 values at 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: 1,470 values at 1000–2000 m, 615 values at 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 … 10 declared · 18,189 flagged
µmol/L (umol/L in metadata/measurement_type.csv) · P06 units UPOX
details
- bounds
- The registry declares
0 … 10 µmol/Lfornitrite; a value outside it is dropped at the ingest (drop_out_of_bounds()). - observed
- Hydrographic Bottle
nitrite0 · median 0.01 · 8.19 µmol/L (5th–95th percentile 0–0.22) - flags
- Hydrographic Bottle
nitriteno2qon 18,228 of 364,442 rows:439 ·818,189; qual_ok keeps 346,253. 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.
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 0–5,351 m · every month
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, v2026.10.21
Cite the release; each dataset's own citation, licence and DOI are on its page — Hydrographic Bottle. The Explorer's Share → Cite writes it for the view you make.