Bottle ammonium
µmol/Lkey btl_ammoniumNERC P01 AMONZZXXP06 units UPOXseries btl_ammonium
CalCOFI holds 69,506 values of it from 4,435 sampling events in one dataset, 2008–2026, from the surface to 3,510 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
- 69,506
- values
- 0
- flagged
- 2008–2026
- years
- 1
- dataset
- 1–3,510 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
btl_ammonium· source columnnh4no flag at this grain
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 = 'btl_ammonium'library(calcofi4r)
con <- cc_get_db() # the promoted release
tbl(con, "obs_env") |> filter(measurement_type %in% c("btl_ammonium"))import calcofi4py as cc
con = cc.cc_get_db()
con.sql("SELECT * FROM obs_env WHERE measurement_type IN ('btl_ammonium')").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: 17 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.
i
Deeper than the climatology reaches: 17 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.
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/Lforbtl_ammonium; a value outside it is dropped at the ingest (drop_out_of_bounds()). - observed
- CTD Cast Files
btl_ammonium0 · median 0 · 33.58 µmol/L (5th–95th percentile 0–0.6) - flags
- CTD Cast Files
btl_ammoniumcarries no quality code at the release grain; qual_ok keeps all 69,506. - 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 1–3,510 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 — CTD Cast Files. The Explorer's Share → Cite writes it for the view you make.