Phosphate concentration
- 440,909
- values
- 305
- flagged
i
305 of these 440,909 values (under 0.1 %) 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). - 17,259
- sampling events
- 1949–2021
- years
- 1
- dataset
- 0–5,351 m
- depth
- every month
- seasons
O4P3− · phosphate(3−) · 94.970 g/mol · CHEBI:18367
Concentration of phosphate per unit volume of the water column. Phosphate may be expressed in terms of mass or quantity of substance.
Seal Analytical continuous-flow AutoAnalyzer 3 (AA3)
820 nm
Bottle sampling methods on calcofi.org ↗How do the eutrophication and pollution impact ocean productivity and water quality?
CalCOFI holds 440,909 values of it from 17,259 sampling events in one dataset, 1949–2021, from the surface to 5,351 m. At 10–50 m it has fallen 0.00 per decade since 1984.R Phosphate is one of the two fertilisers a bloom cannot do without; off Southern California it has risen in the lower pycnocline as oxygen fell, and the nitrogen-to-phosphorus ratio of the water that feeds upwelling has shifted with it.C
other ways to say why · 4
- Where phosphate is high at the surface, deep water has arrived recently and little has yet grown on it. needs a citation before it can be the pick
- GOOS asks How do the eutrophication and pollution impact ocean productivity and water quality? source
- GOOS asks Is the biomass of the ocean changing? source
- Wikipedia A phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid, a.k.a. Phosphate · CC BY-SA 4.0 · rev. 1376284687
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.
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
phosphate· source columnpo4u_m· flag columnpo4q305 flagged
The structure
ChEBI: “A phosphate ion that is the conjugate base of hydrogenphosphate.” · 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
A modification of Bernhardt and Wilhelm: acidic ammonium molybdate forms phosphomolybdic acid, reduced by dihydrazine sulfate to a blue compound, heated to about 55C to develop color, and read in a 10 mm flow cell. (calcofi.org Bottle sampling methods)
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.
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: 7,425 values at 1000–2000 m, 1,682 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: 7,425 values at 1000–2000 m, 1,682 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.
the GOOS specification sheet for this Essential Ocean Variable lists it, and asks
GOOS asks
- How do the eutrophication and pollution impact ocean productivity and water quality?
- 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-queryi
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.
SELECT * FROM read_json('…/v2026.10.05/catalog.json')
-- objects[] WHERE table = 'obs_env'
-- AND partition_value = 'phosphate'library(calcofi4r)
con <- cc_get_db() # the promoted release
tbl(con, "obs_env") |> filter(measurement_type %in% c("phosphate"))import calcofi4py as cc
con = cc.cc_get_db()
con.sql("SELECT * FROM obs_env WHERE measurement_type IN ('phosphate')").df()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.
Range & quality
details
- bounds
- The registry declares
0 … 10 µmol/Lforphosphate; a value outside it is dropped at the ingest (drop_out_of_bounds()). - observed
- Hydrographic Bottle
phosphate0 · median 1.57 · 5.21 µmol/L (5th–95th percentile 0.27–3.16) - flags
- Hydrographic Bottle
phosphatepo4qon 306 of 440,909 rows:41 ·8305; qual_ok keeps 440,604. 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 × 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).
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).
- Bottle phosphate btl_phosphate · CTD Cast Files · 1993–2026 · 144,164 values · P01 PHOSZZXX 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 — Hydrographic Bottle. The Explorer's Share → Cite writes it for the view you make.