Ammonium
Ammonium concentration (QC'd; the source column is named NH3)
µmol/Lkey ammoniaNERC P01 AMONZZXXP06 units UPOXseries ammonia
CalCOFI holds 90,489 values of it from 3,669 sampling events in one dataset, 2008–2021, from the surface to 3,542 m.R Ammonium is nitrogen recycled by zooplankton and bacteria; phytoplankton take it up before nitrate, so production fed by it is “regenerated” rather than “new”.C
- 90,489
- values
- 0
- flagged
- 2008–2021
- years
- 1
- dataset
- 0–3,542 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
ammonia· source columnnh3u_m· flag columnnh3q
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 = 'ammonia'library(calcofi4r)
con <- cc_get_db() # the promoted release
tbl(con, "obs_env") |> filter(measurement_type %in% c("ammonia"))import calcofi4py as cc
con = cc.cc_get_db()
con.sql("SELECT * FROM obs_env WHERE measurement_type IN ('ammonia')").df()The structure 2 structures
ChEBI: “An onium cation obtained by protonation of ammonia.” · 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 660 nm
The Berthelot reaction: hypochlorous acid and phenol react with ammonium in alkaline solution to form indophenol blue, read in a 10 mm flow cell (a modification of Koroleff 1969, 1970). (calcofi.org Bottle sampling methods)
- NH4+ + phenol + hypochlorite (alkaline) -> indophenol blue
- absorbance read at 660 nm
Why it matters 5 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 · 4
- Most nitrogen in the sunlit layer is recycled several times before it sinks; ammonium measures that recycling, excreted by animals and released as bacteria break organic matter down. needs a citation before it can be the pick
- GOOS asks Is the biomass of the ocean changing? source
- Wikipedia Nitrogen cycle source
- Wikipedia Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged (cationic) molecular ion with the chemical formula NH4+ or [NH4]+. Ammonium · CC BY-SA 4.0 · rev. 1376536172
The record’s own history 6 depth bands against the 1993–2013 normal
Each year against the normal i
Deeper than the climatology reaches: 21 values at 1000–2000 m, 31 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: 21 values at 1000–2000 m, 31 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 … 100 declared · 0 flagged
µmol/L (umol/L in metadata/measurement_type.csv) · P06 units UPOX
details
- bounds
- The registry declares
0 … 100 µmol/Lforammonia; a value outside it is dropped at the ingest (drop_out_of_bounds()). - observed
- Hydrographic Bottle
ammonia0 · median 0 · 33.58 µmol/L (5th–95th percentile 0–0.37) - flags
- Hydrographic Bottle
ammonianh3qon 27,689 of 90,489 rows:427,689; qual_ok keeps 90,489. 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 0–3,542 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, v2026.10.21
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.