Mild hypoxic boundary depth (2.4 mL/L)
Mild hypoxic boundary depth: the shallowest depth where oxygen falls to 2.4 mL/L
mkey hypoxic_depth_24P06 units ULAAseries hypoxic_depth_24
one value per cast One value per cast. This measurement is worked out once for each cast rather than read at every depth, so it has no depth profile and no anomaly against a normal; its values are rows of sample_measurement, not of obs_env.
CalCOFI holds 7,608 values of it from 7,608 sampling events in one dataset, 1993–2026, one per cast.R The mild hypoxic boundary, 2.4 mL/L: the first depth at which oxygen is low enough to matter for sensitive animals, above the 1.4 mL/L hypoxic boundary (Rasmus Swalethorp, SIO, 2026-09-24).C
- 7,608
- values
- 0
- flagged
- 1993–2026
- years
- 1
- dataset
- every month
- 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
hypoxic_depth_24· source columnoxygen_ml_l_ave_sta_corrone value per cast no flag at this grain no P01 concept
Explorerdb-queryThis page as JSON R · Python · Parquet
Every way in 6 ways · Parquet · R · Python · JSON
Read from measurements.json of release v2026.11.05, 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.
Explorerdb-querySELECT * FROM read_json('…/v2026.11.05/catalog.json')
-- objects[] WHERE table = 'sample_measurement'
-- then filter the rows:
-- measurement_type IN ('hypoxic_depth_24')library(calcofi4r)
con <- cc_get_db() # the promoted release
tbl(con, "sample_measurement") |> filter(measurement_type %in% c("hypoxic_depth_24"))import calcofi4py as cc
con = cc.cc_get_db()
con.sql("SELECT * FROM sample_measurement WHERE measurement_type IN ('hypoxic_depth_24')").df()How it is measured no method registered yet
No method row is registered for this measurement yet (metadata/measurement_method.csv).
Why it matters 2 ways to say it · EOV Oxygen
the GOOS specification sheet for this Essential Ocean Variable lists it
other ways to say why · 1
- Wikipedia Hypoxia refers to low oxygen conditions. Hypoxia is problematic for air-breathing organisms, yet it is essential for many anaerobic organisms. Hypoxia (environmental) · CC BY-SA 4.0 · rev. 1376149337
Units and range m · 0 … 6500 declared · 0 flagged
m · P06 units ULAA
details
- bounds
- The registry declares
0 … 6500 mforhypoxic_depth_24; a value outside it is dropped at the ingest (drop_out_of_bounds()). - observed
- CTD Derived Products
hypoxic_depth_242.611 · median 196.6 · 515.1 m (5th–95th percentile 90.38–319) - flags
- CTD Derived Products
hypoxic_depth_24carries no quality code at the release grain; qual_ok keeps all 7,608. - 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.
- derivation
- calcofi4db::ctd_hypoxic_depth(threshold 2.4 mL/L) = profile_threshold_depth(direction = 'below') on the station-corrected oxygen pair average of the 1 m bins: the shallowest bin at or below 2.4 mL/L, interpolated linearly with the bin above; a profile already below it at its first bin counts only when that bin is within 20 m of the surface; absent where the cast never reaches 2.4 mL/L. The provider's definition (Rasmus Swalethorp 2026-09-24, questions Q10): the OMZ can sit mid-profile, so the boundary is the shallowest one. Final and preliminary_with_bottle casts only
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 month every month
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, v2026.11.05
Cite the release; each dataset's own citation, licence and DOI are on its page — CTD Derived Products. The Explorer's Share → Cite writes it for the view you make.