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Measurement · Nutrients & Chemistry · µmol/L

Bottle nitrite

NERC P01 NTRIZZXXP06 units UPOX umol/Lkey btl_nitrite series btl_nitrite
143,173
values
0
flagged
8,405
sampling events
1993–2026
years
1
dataset
1–3,510 m
depth
Jan · Feb · Mar · Apr · May · Jun · Jul · Aug · Sep · Oct · Nov
seasons
What

NO2− · nitrite · 46.005 g/mol · CHEBI:16301

Concentration of nitrite per unit volume of the water column. Nitrite may be expressed in terms of mass or quantity of substance.

How
rosette bottle

Seal Analytical continuous-flow AutoAnalyzer 3 (AA3)

520 nm

Bottle sampling methods on calcofi.org ↗

Is the biomass of the ocean changing?

CalCOFI holds 143,173 values of it from 8,405 sampling events in one dataset, 1993–2026, from the surface to 3,510 m. At 10–50 m it has fallen 0.04 per decade since 1993.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

other ways to say why · 3
  • authored 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 measurement

Measured in
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.

  • CTD Cast Files 143,173 values · 8,405 sampling events · 1993–2026 · 1–3,510 m · 109 grid cells · 121 cruises
    series btl_nitrite · source column no2 no flag at this grain

The structure

NO2− nitrite CHEBI:16301 · 46.005 g/mol · the_thing

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

CTD Cast Files · rosette bottle
Seal Analytical continuous-flow AutoAnalyzer 3 (AA3)

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
no flag at this grain
Bottle sampling methods on calcofi.org ↗

Why it matters

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.

The record’s own history
i

Deeper than the climatology reaches: 42 values at 1000–2000 m, 20 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.

Essential Ocean Variable
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

The record

Ways in
i

Read from measurements.json of release v2026.10.05, 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-query
ERDDAP · CTD Cast FilesCalCOFI's own server, the CTD Cast Files table constrained to this series
https://erddap.calcofi.io/erddap/tabledap/calcofi_ctd-cast.html?&measurement_type=%22btl_nitrite%22

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).

By month
i

Values per calendar month, one row per series: CalCOFI's quarterly cruises show as peaks in the months the ships sail.

Range & quality

bounds0 … 10 µmol/Lobserved0 … 8.19 µmol/Lflagged0baselineclimatology ✓
details
bounds
The registry declares 0 … 10 µmol/L for btl_nitrite; a value outside it is dropped at the ingest (drop_out_of_bounds()).
observed
CTD Cast Files btl_nitrite 0 · median 0.032 · 8.19 µmol/L (5th–95th percentile 0–0.5)
flags
CTD Cast Files btl_nitrite carries no quality code at the release grain; qual_ok keeps all 143,173.
baseline
A monthly climatology exists for this measurement (the release's climatology table: 1993–2013, dataset × grid cell × calendar month × 10 m bin), so the Explorer can draw anomalies against it rather than values.

Related measurements
i

The same quantity from another platform or another kind of sample, each its own page and never merged into this one: a dataset's own bottle samples would count that dataset twice, an underway intake is not a cast, and a replicate is not a mean. The reason is the record's (related[].why).

  • Nitrite concentration nitrite · Hydrographic Bottle · 1959–2021 · 364,442 values · P01 NTRIZZXX the same quantity from the CTD files' own bottle samples — plausibly the same physical bottles, so merging them would count the bottle dataset twice

Cite

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.