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Measurement · Nutrients & Chemistry · µmol/L

Bottle silicate

NERC P01 SLCAZZXXP06 units UPOX umol/Lkey btl_silicate series btl_silicate
144,407
values
0
flagged
8,420
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

O4Si4− · silicate(4−) · 92.082 g/mol · CHEBI:29241

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

How
rosette bottle

Seal Analytical continuous-flow AutoAnalyzer 3 (AA3)

660 nm

Bottle sampling methods on calcofi.org ↗

Is the biomass of the ocean changing?

CalCOFI holds 144,407 values of it from 8,420 sampling events in one dataset, 1993–2026, from the surface to 3,510 m. At 10–50 m it has fallen 0.44 per decade since 1993.R Diatoms build glass shells, so silicate is the nutrient that decides whether a bloom is made of them; off Southern California it has been rising in the upper pycnocline and falling in the lower one.C

other ways to say why · 3
  • authored When silicate runs out before nitrate does, the bloom shifts away from diatoms and toward cells that sink more slowly and feed a different food web. needs a citation before it can be the pick
  • GOOS asks Is the biomass of the ocean changing? source
  • Wikipedia In chemistry, a silicic acid is any chemical compound containing the element silicon attached to oxide and hydroxyl groups, with the general formula [H2xSiOx+2]n or, equivalently, [SiOx(OH)4−2x]n. Orthosilicic acid is a representative example. Silicic acid · CC BY-SA 4.0 · rev. 1357664652

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 144,407 values · 8,420 sampling events · 1993–2026 · 1–3,510 m · 109 grid cells · 121 cruises
    series btl_silicate · source column sil no flag at this grain

The structure

O4Si4− silicate(4−) CHEBI:29241 · 92.082 g/mol · the_thing

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)

Armstrong (1967): acidic ammonium molybdate forms silicomolybdic acid, reduced by stannous chloride to a blue compound (tartaric acid suppresses phosphate interference), read in a 10 mm flow cell. (calcofi.org Bottle sampling methods)

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: 54 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_silicate%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 … 300 µmol/Lobserved0 … 174.5 µmol/Lflagged0baselineclimatology ✓
details
bounds
The registry declares 0 … 300 µmol/L for btl_silicate; a value outside it is dropped at the ingest (drop_out_of_bounds()).
observed
CTD Cast Files btl_silicate 0 · median 16.13 · 174.5 µmol/L (5th–95th percentile 1.37–73.6)
flags
CTD Cast Files btl_silicate carries no quality code at the release grain; qual_ok keeps all 144,407.
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).

  • Silicate concentration silicate · Hydrographic Bottle · 1959–2021 · 381,685 values · P01 SLCAZZXX 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.