Measurement · Nutrients & Chemistry · µmol/L

Reported ammonium concentration (pre-QC)

The registry carries no authored label for this measurement, so the name above is the canonical series' own description in metadata/measurement_type.csv (variable.csv holds the authored labels, five today).

NERC P01 AMONZZXXP06 units UPOX umol/Lkey r_ammonium series r_ammonium

90,509
values: 3,670
sampling events: 2008–2021
years: 1
dataset: 0–3,542 m
depth: Jan · Feb · Mar · Apr · May · Jun · Jul · Aug · Oct · Nov
seasons

Heads-up The r_ammonium series from Hydrographic Bottle carries no flag at this grain, so its values cannot be screened this way.

Measured in

Hydrographic Bottle 90,509 values · 3,670 sampling events · 2008–2021 · 0–3,542 m · 87 grid cells · 52 cruises

series r_ammonium · source column r_nuts reported · pre-QC no flag at this grain

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.

By depth

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

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

Range & quality

bounds: The registry declares 0 … 100 µmol/L for r_ammonium; a value outside it is dropped at the ingest (drop_out_of_bounds()).
observed: Hydrographic Bottle r_ammonium 0 · median 0 · 33.58 µmol/L (5th–95th percentile 0–0.37)
flags: Hydrographic Bottle r_ammonium carries no quality code at the release grain; qual_ok keeps all 90,509.
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.
derivation: reported value interpolated to standard depth (pre-QC, decodr); carries no quality code by design; not an input for further interpolation

Related measurements

Bottle ammonium btl_ammonium · CTD Cast Files · 2008–2025 · 68,242 values · P01 AMONZZXX the same quantity from the CTD files' own bottle samples — plausibly the same physical bottles, so merging them would count the bottle dataset twice

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).

Ways in

Explorermaps, sections and time series of this measurement — opens prefilled
https://calcofi.io/explore/?var=r_ammonium
Explorer · a depth section vs normalthe newest cruise's section against the climatology baseline
https://calcofi.io/explore/?lens=section&var=r_ammonium&anom=1
db-querySQL in your browser — the shell opens with this query
https://calcofi.io/db-query/?sql=SELECT+%2A+FROM+__TBL%3Aobs_env__+WHERE+measurement_type+%3D+%27r_ammonium%27+LIMIT+100%3B
ERDDAP · Hydrographic BottleCalCOFI's own server, the Hydrographic Bottle table constrained to this series
https://erddap.calcofi.io/erddap/tabledap/calcofi_bottle.html?&measurement_type=%22r_ammonium%22
Parquetobs_env is partitioned by measurement_type in the content-addressed store — resolved through the release catalog, never a path built by hand
```
SELECT * FROM read_json('…/v2026.09.10/catalog.json')
-- objects[] WHERE table = 'obs_env'
--   AND partition_value = 'r_ammonium'
```

library(calcofi4r)
con <- cc_get_db()                      # the promoted release
tbl(con, "obs_env") |> filter(measurement_type %in% c("r_ammonium"))

Python

import calcofi4py as cc
con = cc.cc_get_db()
con.sql("SELECT * FROM obs_env WHERE measurement_type IN ('r_ammonium')").df()

This page as data

JSONthis measurement's entry of the release record, verbatim
https://calcofi.io/measurements/r_ammonium.json

Read from measurements.json of release v2026.09.10, 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.

Cite

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.