{
  "key": "hypoxic_depth_24",
  "slug": "hypoxic_depth_24",
  "label": "Mild hypoxic boundary depth: the shallowest depth where oxygen falls to 2.4 mL/L",
  "short_label": "Mild hypoxic boundary depth (2.4 mL/L)",
  "description": "Mild hypoxic boundary depth: the shallowest depth where oxygen falls to 2.4 mL/L",
  "units": "m",
  "units_nerc_p06": "http://vocab.nerc.ac.uk/collection/P06/current/ULAA/",
  "nerc_p01": null,
  "category": {
    "key": null,
    "name": "Physical Oceanography",
    "icon": "cat-physical",
    "realm": "env",
    "order": 1
  },
  "is_unified": false,
  "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",
  "climatology": true,
  "bounds": {
    "valid_min": 0,
    "valid_max": 6500,
    "declared_by": [
      "hypoxic_depth_24"
    ]
  },
  "totals": {
    "n_values": 7608,
    "n_samples": 7608,
    "n_roots": 7608,
    "n_datasets": 1,
    "year_min": 1993,
    "year_max": 2026,
    "depth_min_m": null,
    "depth_max_m": null,
    "qual_ok_n": 7608,
    "n_flagged": 0
  },
  "series": [
    {
      "measurement_type": "hypoxic_depth_24",
      "dataset_key": "calcofi_ctd-derived",
      "source_column": "oxygen_ml_l_ave_sta_corr",
      "qual_column": null,
      "description": "Mild hypoxic boundary depth: the shallowest depth where oxygen falls to 2.4 mL/L",
      "units": "m",
      "nerc_p01": null,
      "is_canonical": true,
      "n_values": 7608,
      "n_samples": 7608,
      "n_roots": 7608,
      "n_cells": 108,
      "n_cruises": 136,
      "year_min": 1993,
      "year_max": 2026,
      "depth_min_m": null,
      "depth_max_m": null,
      "years": {
        "1993": 113,
        "1994": 227,
        "1995": 228,
        "1996": 233,
        "1997": 238,
        "1998": 350,
        "1999": 227,
        "2000": 225,
        "2001": 222,
        "2002": 229,
        "2003": 225,
        "2004": 221,
        "2005": 239,
        "2006": 236,
        "2007": 248,
        "2008": 243,
        "2009": 246,
        "2010": 238,
        "2011": 251,
        "2012": 224,
        "2013": 265,
        "2014": 198,
        "2015": 239,
        "2016": 277,
        "2017": 257,
        "2018": 240,
        "2019": 185,
        "2020": 194,
        "2021": 204,
        "2022": 171,
        "2023": 256,
        "2024": 208,
        "2025": 188,
        "2026": 63
      },
      "months": [
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        460,
        314,
        1639,
        84,
        101,
        1266,
        543,
        102,
        767,
        940,
        21
      ],
      "depth_bands": {
        "0-10": 0,
        "10-50": 0,
        "50-100": 0,
        "100-200": 0,
        "200-500": 0,
        "500-1000": 0,
        "1000-2000": 0,
        "2000+": 0
      },
      "qual": {
        "none": 7608
      },
      "qual_ok_n": 7608,
      "n_flagged": 0,
      "observed": {
        "min": 2.61111879408104,
        "p05": 90.3791581632653,
        "p50": 196.640398550725,
        "p95": 318.951536371237,
        "max": 515.109406952965
      },
      "out_of_bounds": {
        "n": 0,
        "min": null,
        "max": null
      },
      "flags": [
        "no_flag_at_grain",
        "no_p01"
      ],
      "grain": "sample"
    }
  ],
  "related": [],
  "flags": [
    "no_label"
  ],
  "face": {
    "kind": "scale",
    "face_of": null,
    "stands_in_note": null,
    "source": "no NERC P01 on this key; shows its own familiar-scale figure only (D3)"
  },
  "why": [
    {
      "rank": 1,
      "kind": "authored",
      "text": "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).",
      "bibkeys": [
        "bograd2008"
      ],
      "source_url": null,
      "eov": "Oxygen",
      "goos_doc": "https://goosocean.org/document/17508"
    },
    {
      "rank": 2,
      "kind": "wikipedia",
      "text": "Hypoxia (environmental)",
      "bibkeys": [],
      "source_url": "https://en.wikipedia.org/wiki/Hypoxia_(environmental)",
      "eov": "Oxygen",
      "goos_doc": "https://goosocean.org/document/17508"
    }
  ],
  "grain": "sample"
}