Research ArticleGEOCHEMISTRY

Biogeochemical controls of surface ocean phosphate

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Science Advances  28 Aug 2019:
Vol. 5, no. 8, eaax0341
DOI: 10.1126/sciadv.aax0341
  • Fig. 1 Global distribution of surface DIP.

    (A) Observed DIP using high-sensitivity techniques ([DIP]obs). (B and C) Climatologically predicted surface DIP concentrations ([DIP]predict) from the World Ocean Atlas (WOA13) (B) and GLODAPv2 (C). (D to L) Surface DIP concentrations predicted using ESM predictions. The dataset has a total of 50,591 observations including 41,747 from the top 30 m of the water column (shown here). Climatological and ESM-predicted values are at 1° resolution and represent annual means.

  • Fig. 2 Relationships between DIP, chlorophyll, and NPP among observations and ESMs.

    (A and B) Relationships between [DIP]obs and chlorophyll concentrations (Chlsat) (A) or NPP (NPPsat) (B). Chlorophyll and NPP are from MODIS satellite observations (n = 38,653). (C and D) Relationships between predicted DIP ([DIP]predict) and chlorophyll concentrations (Chlpredict) (C) or NPP (NPPpredict) (D) from ESMs. Chlorophyll or NPP relationships from ESMs are depicted in detail in fig. S3.

  • Fig. 3 Changes in the global distribution of DIP as a function of dust deposition patterns.

    (A) Estimated DIP in the current ocean (i.e., control scenario). (B) Estimated DIP for the scenario of increased dust deposition in the Southern Hemisphere gyre (reaching North Pacific Ocean subtropical gyre levels). (C) Estimated DIP for the scenario of even dust deposition across each subtropical gyre. (D) Differences in DIP between the “Southern Hemisphere scenario” [as shown in (B)] and current levels [as shown in (A)]. (E) Differences in DIP between “even gyre scenario” [as shown in (C)] and current levels [as shown in (A)]. Ocean biogeochemistry was simulated with the ocean component of the CESM (v2).

  • Table 1 Summary of cruise data for this study.

    MQ, Milli-Q water; NaOH, supernatant following alkaline precipitation of phosphate; Unp., unpublished.

    Cruise no.IDRegionNo. of samples(<30 m)MethodFrozenPrefilteredBlankRef.
    1Cook-BookNorth East Pacific21565MAGICYesNoNaOHUnp.
    2BULACentral Pacific488MAGICYesNoNaOHUnp.
    3BeachbashCentral Pacific13142MAGICYesNoNaOHUnp.
    4SUPER-HI-CATNorth East Pacific8442MAGICYesNoNaOHUnp.
    5BIOSOPESouth East Pacific28877MAGICNoYesNaOH(6)
    6PROSOPEMediterranean Sea13726MAGICNoYesNaOH(39)
    7AMT12Atlantic Ocean9345LWCCNoNoMQ(10)
    8AMT13Atlantic Ocean6010LWCCNoNoMQ(10)
    9AMT14Atlantic Ocean20959LWCCNoNoMQ(10)
    10AMT15Atlantic Ocean220128LWCCNoNoMQ(10)
    11AMT16Atlantic Ocean272117LWCCNoNoMQ(10)
    12AMT17Atlantic Ocean27692LWCCNoNoMQ(10)
    13BOUMMediterranean Sea424167LWCCNoNoMQ(40)
    14AR16Western North Atlantic9445MAGICYesYesNaOHUnp.
    15COST2005North Pacific17460LWCCNoNoMQ(41)
    16CR 1455, CR 1487, CR 950South China Sea2424MAGICYesNoNaOH(42)
    17POOB2North Pacific1313MAGICYesNoNaOH(43)
    18GA03North Atlantic335168LWCCNoNoMQ(44)
    19KH04-5West Pacific Ocean13,99713,997LWCCNoNoNaOH(22)
    20KH05-2West Pacific Ocean6,1756,175LWCCNoNoNaOH(22)
    21SCSSouth China Sea4512LWCCNoNoMQ(19)
    22MR09-01South Pacific3838LWCCYesNoNaOH(45)
    23R/V OceanusNorth West Atlantic17175MAGICYesNoMQ(21)
    24BATSNorth West Atlantic1815444MAGICYesYesNaOH(32)
    25AE1319North West Atlantic4212MAGICYesYesNaOH(5)
    26Trophic BATSNorth West Atlantic893183MAGICYesYesNaOH(32)
    27NH1418Central Pacific18848MAGICYesYesNaOH(46)
    28BVALNorth West Atlantic1,254290MAGICYesYesNaOH(5)
    29AE1206/1219North West Atlantic11032MAGICYesYesNaOH(5)
    30KH14-3Central North Pacific7439LWCCMixNoNaOH(47)
    31KH09-5Central Indian Ocean4919LWCCNoNoNaOH(48)
    32KH-06-2, MR07-01,
    MR07-06, KT-06-21,
    Nagasaki-Maru 242
    West Pacific Ocean4343LWCCMixNoNaOH(49)
    33Umitaka-Maru cruiseIndian Ocean7,0737073LWCCNoNoNaOH(50)
    34HOTNorth Pacific2,545656MAGICYesNoNaOH(51)
    35NH1417North East Pacific3828MAGICYesNoNaOH(52)
    36MixedSouth China Sea2,2092209SPENoNoMQ(20)
    37MixedSouth China Sea1,592912MAGICYesNoNaOH(53)
    38GA06/D361Central North Atlantic176176LWCCNoNoMQ(54)
    39GP13South West Pacific77791LWCCNoNoMQ(17)
    40KT-05-24, KT-06-21, KT-07-22North West Pacific Ocean7,8387,838LWCCNoNoNaOH(55)
    41GEOTRACES GApr08, JC150North Atlantic119119LWCCNoNoMQUnp.
    42OUTPACESouth Pacific Ocean9516LWCCNoYesNone(56)

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/8/eaax0341/DC1

    Fig. S1. Systematic bias in predicted phosphate concentrations.

    Fig. S2. Relationship between observed DIP ([DIP]obs) and shipboard NPP (NPPobs).

    Fig. S3. Relationship between predicted surface DIP ([DIP]predict) and predicted chlorophyll concentrations (Chlpredict) across ESMs.

    Fig. S4. Relationship between predicted surface DIP ([DIP]predict) and predicted integrated NPP (NPPpredict) across ESMs.

    Fig. S5. Comparison of the predicted surface DIP distribution between CESM1 and CESM2.

    Fig. S6. Distribution and changes to the predicted atmospheric Fe deposition and N fixation in the global ocean.

    Fig. S7. Predicted global variation in the vertical velocity.

    Fig. S8. Relationship between the vertical velocity and observed near-surface DIP concentrations.

    Fig. S9. Elemental supply ratios in nutricline waters.

    Table S1. ESMs used in this study.

    Table S2. Abbreviations.

    References (5762)

  • Supplementary Materials

    This PDF file includes:

    • Fig. S1. Systematic bias in predicted phosphate concentrations.
    • Fig. S2. Relationship between observed DIP (DIPobs) and shipboard NPP (NPPobs).
    • Fig. S3. Relationship between predicted surface DIP (DIPpredict) and predicted chlorophyll concentrations (Chlpredict) across ESMs.
    • Fig. S4. Relationship between predicted surface DIP (DIPpredict) and predicted integrated NPP (NPPpredict) across ESMs.
    • Fig. S5. Comparison of the predicted surface DIP distribution between CESM1 and CESM2.
    • Fig. S6. Distribution and changes to the predicted atmospheric Fe deposition and N fixation in the global ocean.
    • Fig. S7. Predicted global variation in the vertical velocity.
    • Fig. S8. Relationship between the vertical velocity and observed near-surface DIP concentrations.
    • Fig. S9. Elemental supply ratios in nutricline waters.
    • Table S1. ESMs used in this study.
    • Table S2. Abbreviations.
    • References (5762)

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