Ruttenberg,K.C.(2003): 8.13 The global phosphate cycle. Treatise on Geochemistry, 8, 585-643.

『8.13 世界のリン循環』

8.13.1. Introduction
8.13.2. The global phosphorus cycle: Overview The terrestrial phosphorus cycle Transport of phosphorus from continents to the ocean Human impacts on the global phosphorus cycle The marine phosphorus cycle
8.13.3. Phosphorus biogeochemistry and cycling: Current research Phosphorus cycling in terrestrial ecosystems and soils Phosphorus cycling in terrestrial aquatic systems: Lakes, rivers and estuaries Biogeochemistry and cycling of phosphorus in lakes Biogeochemistry and cycling of phosphorus in rivers and estuaries Biogeochemistry and cycling of phosphorus in the modern ocean Historical perspective: the marine phosphorus budget Diagenesis and burial of phosphorus in marine sediments
   Sedimentary organic phosphorus: composition and reactivity
   Authigenic carbonate fluorapatite (CFA): modern phosphorites
   Disseminated authigenic carbonate fluorapatite
   Experimental studies of authigenic apatite precipitation
   Other authigenic phosphate minerals
   Sedimentary organic carbon to organic phosphorus ((C:P)org) ratios
   Coupled iron-phosphorus cycling Phosphorus in the oceanic water column: composition and cycling
   Dissolved inorganic phosphorus (DIP)
   Dissolved organic phosphorus (DOP)
   Water column C : P ratios
   Cosmogenic 32P and 33P as tracers of phosphorus cycling in surface waters Phosphorus limitation of marine primary photosynthetic production The oceanic residence time of phosphorus Phosphorus cycling over long, geologic timescales The role of tectonics in the global phosphorus cycle Links to other biogeochemical cycles of long, geologic timescales
   The nutrient - CO2 connection
   The phosphorus - iron - oxygen connection Phosphorus in paleoceanography: P-burial as a proxy for weathering, paleoproductivity, and climate change Ancient phosphorites

8.13.4. Summary
 The global cycle of phosphorus is truly a biogeochemical cycle, owing to the involvement of phosphorus in both biochemical and geochemical
reactions and pathways. There have been marked advances since the 1990s on numerous fronts of phosphorus research, resulting from application of new methods, as well as rethinking of old assumptions and paradigms. An oceanic phosphorus residence time on the order of 10-20 kyr, a factor of 5-10 shorter than previously cited values, casts phosphorus in the role of a potential player in climate change on glacial-interglacial timescales through the nutrient-CO2 connection. This possibility is bolstered by findings in a number of recent studies that phosphorus does function as the limiting nutrient in some modern oceanic settings. Both oxygen isotopes in phosphate (δ18O-PO4) and in situ produced radiophosphorus isotopes (33P and 32P) are providing new insights into how phosphorus is cycled through metabolic pathways in the marine environment. 31P-NMR and a new probe for DOP-hydrolyzing enzymes are illuminating the composition of DOP and its importance for phytoplankton nutrition. Finally, new ideas about global phosphorus cycling on long, geologic timescales include a possible role for phosphorus in regulating atmospheric oxygen levels via the coupled iron.phosphorus.oxygen cycles, and the potential role of tectonics in setting the exogenic mass of phosphorus. The interplay of new findings in each of these areas, and others touched upon in this review chapter, are providing us with a fresh
look at the global phosphorus cycle, one which is sure to evolve further as these and other new areas are explored in more depth by future studies.』


Figure 1 The major reservoirs and fluxes of the global phosphorus cycle are illustrated (see Tables 1 and 2, and text). The oceanic photic zone, idealized in the cartoon, is typically thinner in coastal environments due to turbidity from continental terrigenous input, and deepens as the water column clarifies with distance away from the continental margins. The distribution of phosphorus among different chemical/mineral forms in marine sediments is given in the pie diagrams, where the abbreviations used are: organic phosphorus (Porg), iron-bound phosphorus (PFe), detrital apatite (Pdetr), authigenic/biogenic apatite (Pauth). The Porg, PFe, and Pauth reservoirs represent potentially reactive-P pools (see text and Tables 2 and 3 for discussion), whereas the Pdetr pool reflects mainly detrital apatite weathered off the continents and passively deposited in marine sediments (note that Pdetr is not an important sedimentary phosphorus component in abyssal sediments, far from continents). Continental margin P-speciation data were compiled from Louchouarn et al. (1997), and Ruttenberg and Berner (1993). Abyssal sediment P-speciation data were compiled from Filippelli and Delaney (1996), and Ruttenberg (1990). The “global phosphorus cycle” cartoon is from Ruttenberg (2002). The vertical water column phosphate distributions typically observed in the three ocean basins are shown in the panel to the right of the “global phosphorus cycle” cartoon, and are from Sverdrup et al. (1942).

Ruttenberg,K.C.(2003)による『8.13 The global phosphate cycle』から

図1 世界のリン循環の主なリザーバとフラックスが図示されている(表1と表2と本文を参照)。海洋有光層帯は、図では理想化されているが、大陸の砕屑物の流入による混濁によって沿岸環境では典型的に薄くなっており、大陸縁から離れて水柱が澄むにつれて深くなる。海洋堆積物中の異なる化学的/鉱物学的形態間でのリンの分布は円グラフで与えてあり、使用されている略称は次のとおり:有機リン(Porg)、鉄結合リン(PFe)、砕屑アパタイト(Pdetr)、自生/生物源アパタイト(Pauth)。PorgとPFeとPauthのリザーバは潜在的に反応性Pのプールを示し(議論は本文および表2と表3を参照)、Pdetrのプールは主に大陸から風化で流出した砕屑アパタイトであり、海洋堆積物中に受動的に堆積した(Pdetrは、大陸から離れた遠洋堆積物中の重要な堆積リン成分ではないことに注意)。大陸縁のP化学種データはLouchouarn et al.(1997)およびRuttenberg and Berner(1993)からまとめた。遠洋堆積P化学種データはFilippelli and Delaney(1996)およびRuttenberg(1990)からまとめた。『世界のリン循環』の図はRuttenberg(2002)からのものである。3大海盆で典型的に観測された垂直水柱リン分布は『世界のリン循環』の図の右にパネル画として示されているが、Sverdrup et al.(1942)からのものである。

表1 世界のリン循環において活発な主要リザーバおよびその滞留時間(注は略)
リザーバの記載 リザーバの大きさ
文献 滞留時間
R1 堆積物(地殻の岩石および>60cm深度の土壌および海洋堆積物) 27,000,000-130,000,000 b、a=c=d 42,000,000-201,000,000
R2 陸地(≒<60cm深度の全土壌:有機+無機) 3,100-6,450 b、a=c=d 425-2,311
R3 陸地生物 83.9-96.8 b、a=c=d 13-48
R4 海洋表層、0-300m(全溶存P) 87.4 a=c 2.46-4.39
R5 深海、300-3300m(全溶存P) 2,810 a=c&d 1,502
R6 海洋生物 1.61-4.45 b&d、a=c&d 0.044-0.217(16-78日)
R7 鉱床P 323-645 a=c、b&d 718-1,654
R8 大気P 0.0009 b=c=d 0.009(80時間)
a: Lerman et al.(1975), b: Richey(1983), Jahnke(1992), Mackenzie et al.(1993)

表2 主要なリン・リザーバ間のフラックス(注は略)

フラックスの記載 フラックス
F12 岩石/堆積物→土壌(浸食/風化、土壌蓄積) 0.645 a=c&d
F21 土壌→岩石/堆積物(深部埋没、岩石化) 0.301-0.603 d、a=c
F23 土壌→陸地生物 2.03-6.45 a=c、b&d
F32 陸地生物→土壌 2.03-6.45 a=c、b&d
F24(d) 土壌→海洋表層(河川全溶存Pフラックス) 0.032-0.058 e、a=c;TDPの約>50%はDOP(e)
F24(p) 土壌→海洋表層(河川粒子状Pフラックス) 0.59-0.65 d、e;RSPM-Pの約40%は有機P(e);海洋に流入たものの25〜45%は反応性であると見積られる(f)
F46 海洋表層→海洋生物 19.35-35 b、d;a=c=33.5、bは上限が32.3と報告している;dは下限が28.2と報告している
F64 海洋生物→海洋表層 19.35-35 b、d;a&c=32.2、bは上限が32.3と報告している;dは下限が28.2と報告している
F65 海洋生物→深海(微粒子雨) 1.13-1.35 d、a=c
F45 海洋表層→深海(沈降流) 0.581 a=c
F54 深海→海洋表層(湧昇流) 1.87 a=c
F42 海洋表層→陸地(漁業) 0.01 d
F72 鉱床P→陸地(土壌) 0.39-0.45 a=c=d、b
F28 陸地(土壌)→大気 0.14 b=c=d
F82 大気→陸地(土壌) 0.1 b=c=d
F48 海洋表層→大気 0.01 b=c=d
F84 大気→海洋表層 0.02-0.05 c、b;dは0.04;大気エアロゾルPの約30%は溶解性(g)
sFms 海洋堆積物蓄積(全) 0.265-0.280 i、j;高い見積りとして(j)、続成作用帯以下の堆積物P濃度の使用は底生性再鉱化フラックスを経るP損失を無条件に計算しており、先史時代の正味の埋没フラックスを与えている。反応性Pの埋没の見積りは(j)の注を参照
sFcs 大陸縁海洋堆積物→埋没 0.150-0.223 j、i:報告値は全Pを反映しており、反応性Pの埋没は全Pの40〜75%を構成する(h)。これらの値は農業開始以前のフラックスを反映しており、現代の値は0.33と見積られる(d)
sFas 遠洋(深海)堆積物→埋没 0.042-0.130 i、j;a=cは0.055の値を与えている。このフラックスの90-100%は反応性Pであると見積られている(h)。これらの値は農業開始以前のフラックスを反映しており、現代の値は0.32(d)から0.419(b)と見積られる
sFcbf 沿岸堆積物→沿岸海水(再鉱化、底生性フラックス)) 0.51-0.84 d、k;これらの値は農業開始以前のフラックスを反映しており、現代の値は±40%の不確かさで1.21と見積られる(k)
sFabf 遠洋堆積物→深海(再鉱化、底生性フラックス)) 0.41 k;この値は農業開始以前のフラックスを反映しており、現代の値は±30%の不確かさで0.52と見積られる(k)

Figure 2 The fate of phosphorus during soil formation can be viewed as the progressive dissolution of primary mineral phosphorus (dominantly apatite), some of which is lost from the system by leaching (decrease in Ptotal), and some of which is reincorporated into nonoccluded, occluded, and organic fractions within the soil. Nonoccluded phosphorus is defined as phosphate sorbed to surfaces of hydrous oxides of iron and aluminum, and calcium carbonate. Occluded phosphorus refers to phosphorus present within the mineral matrix of discrete mineral phases. The initial buildup in organic phosphorus results from organic matter return to soil from vegetation supported by the soil. The subsequent decline in Porganic is due to progressive mineralization and soil leaching. The timescale over which these transformations occur depends upon the initial soil composition, topographic, and climatic factors (after Walker and Syers, 1976).

Ruttenberg,K.C.(2003)による『8.13 The global phosphate cycle』から

図2 土壌生成の間のリンの運命は一次鉱物リン(主にアパタイト)の累進的な溶解として考えることができ、その一部は浸出によって系から失われ(Ptotalの減少)、その一部は土壌内の非吸蔵画分および吸蔵画分および有機画分に組み込まれる。非吸蔵リンは鉄とアルミニウムの水酸化物および炭酸カルシウムの表面に吸着されたリン酸として定義される。吸蔵リンは個々の鉱物相の鉱物マトリックス内に存在するリンとみなせる。有機リンの最初の形成は土壌によって支えられた植物から土壌へ戻った有機物から生じる。Porganicの引き続く減少は累進的な鉱化と土壌浸出による。これらの変化が起こる時間スケールは最初の土壌組成と地形と気候要因に依存する(Walker and Syers,1976から)。

表3 修正した海洋リン入力フラックスと除去フラックスおよび概算された海洋滞留時間(注は略)
  フラックスの記載 フラックス
F84 大気→海洋表層 0.02-0.05  
F24(d) 土壌→海洋表層(河川溶存Pフラックス) 0.032-0.058  
F24(p)     土壌→海洋表層(河川粒子状Pフラックス) 0.59-0.65  
最小反応性P入力フラックス 0.245 12,000
最大反応性P入力フラックス 0.301 10,000
sFcs 大陸縁海洋堆積物中の全埋没リンの最適見積り(表2、注j) 0.150  
sFas 遠洋堆積物中の全埋没リンの最適見積り(表2、注j) 0.130  
海洋堆積物中の埋没反応性Pの最小見積り 0.177 17,000
海洋堆積物中の埋没反応性Pの最大見積り 0.242 12,000

Figure 3 Processes important during early diagenetic transformations of phosphorus in marine sediments are illustrated. Sources of phosphorus to the sediment.water interface include allocthonous river-borne inorganic and organic phosphorus, and autocthonous, biogenic phosphorus formed through photosynthesis and subsequent foodweb processes. Once delivered to the sediment.water interface, organic phosphorus is subject to breakdown via microbial respiration, a process often called “mineralization” because it transforms organic matter into its inorganic, “mineral” constituents, such as phosphate, nitrate, and carbon dioxide (dissolved organic phosphorus, nitrogen, and carbon, are also products of respiration, although these products are not shown). A representative equation for oxygenic respiration is given as an example, but a well-documented sequence of electron acceptors are utilized by microbial communities, typically in order of decreasing metabolic energy yield, to affect respiration (nitrate, oxides of iron and manganese, sulfate; however, for exceptions to this strict hierarchy of oxidants, see Canfield, 1993; Aller, 1994; Hulth et al., 1999; Anschutz et al., 2000). All of these respiration reactions result in a buildup of phosphate and other metabolites in pore waters. Schematic of pore-water profiles for the general situation of steadystate phosphate diagenesis, with organic matter as the sole source of phosphate to pore waters, is after Berner (1980). (Another important source of phosphate to pore waters, not depicted in this cartoon, is release of sorbed phosphate from host Fe-oxyhydrixides when these phases are buried into suboxic and anoxic zones within the sediment (see text for discussion).) Once released to pore waters, phosphate can escape from sediments via diffusional transport, resuspension, or irrigation by benthos. An important process for retention of pore-water phosphate within sediments is secondary authigenic mineral formation. The dashed profiles illustrate phosphate profile shapes encountered when (i) organic matter breakdown is the dominant process, and there is no precipitation (km = 0: exponential increase of pore-water phosphate with increasing depth), and (ii) there is very rapid precipitation (km = infinity: vertical gradient at a concentration (Ceq) in equilibrium with the authigenic phase). The intermediate case is given in the solid curve, where a reversal of the initially exponentially increasing pore-water gradient is observed, indicating removal of phosphate from pore waters during phosphate mineral authigenesis.

Ruttenberg,K.C.(2003)による『8.13 The global phosphate cycle』から

図3 海洋堆積物中のリンの早期続成作用による変化の重要な過程が図示されている。

Figure 6 Schematic diagram of the coupled iron and phosphate cycles in during early diagenesis in marine sediments. Light gray ovals and circles represent solid phases, black arrows are solid-phase fluxes. Whiteoutlined black arrows indicate reactions, white arrows are diffusion pathways. Ferric oxyhydroxides (FeOOH) precipitated in the water column and at the sediment-water interface scavenge phosphate (PO43-) and some fluoride (F-) from seawater. During burial and mixing, microbial respiration of organic matter utilizes a sequence of electron acceptors in order of decreasing thermodynamic advantage. Oxygen is used first, followed by nitrate and nitrite, manganese- and ironoxyhydroxides, and sulfate. Phosphate is liberated to pore waters upon decomposition of organic matter, and reductive dissolution of FeOOH liberates Fe2+, PO43-, and F-, resulting in increases in concentrations of these ions in pore waters (e.g., see phosphate profile in Figure 3 and model curves in Figure 4). If concentration levels are sufficient to exceed saturation with respect to authigenic CFA (denoted as francolite in figure), this phase will precipitate out of solution, sometimes first as a precursor phase that then recrystallizes to CFA proper. Excess phosphate diffuses up towards the sediment-water interface, where it is readsorbed by FeOOH. Ferrous iron (Fe2+) diffuses both downwards to be precipitated with sulfide as FeS in the anoxic zone of sediments, and upwards to be re-oxidized in the oxic zone, where it is reprecipitated as FeOOH. The Fe-redox cycle provides an effective means of trapping phosphate in sediments, and can promote the precipitation of CFA (after Jarvis et al., 1994).

Ruttenberg,K.C.(2003)による『8.13 The global phosphate cycle』から

図6 海洋堆積物の早期続成作用の間の結合した鉄とリン循環の概略図。

Figure 7 Locations of disseminated (nonphosphorite) authigenic CFA occurrence, as identified using the SEDEX method, as well as locations of fossil, recent, and undated phosphorites. Note that most phosphorites are located in continental margin areas characterized by upwelling, a process whereby nutrient-rich deep waters are advected to the surface causing high biological productivity and a resulting large flux of organic matter to underlying sediments. Sites of disseminated CFA, in contrast, are not restricted to these classical phosphorite-forming environments. Disseminated CFA data are from Cha, 2002 (East Sea between Korea and Japan); Delaney and Anderson, 1997 (Ceara Rise); Filippelli, 2001 (Saanich Inlet); Filippelli and Delaney, 1996 (eastern and western equatorial Pacific); Kim et al., 1999 and Reimers et al., 1996 (California Borderland Basins); Louchouarn et al., 1997 (Gulf of St. Lawrence); Lucotte et al., 1994 (Labrador Sea); Ruttenberg and Berner, 1993 (Long Island Sound and Gulf of Mexico); Slomp et al., 1996a (North Atlantic continental platform; Van der Zee et al., 2002 (Iberian margin in the NE Atlantic). See text for more detailed discussion of selected studies. Figure is modified after Kolodny (1981), by addition of disseminated CFA locales; see Kolodny (1981) for discussion of phosphorite locales.

Ruttenberg,K.C.(2003)による『8.13 The global phosphate cycle』から

図7 SEDEX法を用いて同定された散在した(非リン酸塩岩)自生CFA(Authigenic Carbonate Fluorapatite、自生炭酸フッ素アパタイト)の生成位置、化石・現生・年代不明のリン鉱の位置も。

Figure 8 Sequence of extractants and extraction conditions that make up the SEDEX sequential extraction method for quantifying different forms of phosphorus in marine sediments (after Ruttenberg, 1992).

Ruttenberg,K.C.(2003)による『8.13 The global phosphate cycle』から

図8 海洋堆積物中の異なる形態のリンを定量するためのSEDEX連続抽出法を構成する一連の抽出剤と抽出条件(Ruttenberg,1992から)

Figure 13 Distribution of phosphoric acid species as a function of pH, and dissociation constants, in (a) pure water; (b) 0.68 M NaCl; and (c) artificial seawater of salinity 33 ppt (after Kester and Pytkowicz, 1967).

Ruttenberg,K.C.(2003)による『8.13 The global phosphate cycle』から

図13 (a)純水と(b)0.68モルNaCl溶液と(c)塩分33パーミルの人工海水における、pHと解離定数の関数としてのリン酸塩化学種の分布(Kester and Pytkowiez,1967から)

Figure 14 Calculated speciation of inorganic phosphate in seawater at 20 8C, 34.8 ppt salinity, and pH 8 (after Atlas et al., 1976).

Ruttenberg,K.C.(2003)による『8.13 The global phosphate cycle』から

図14 20℃で34.8パーミルでpH 8の海水中の無機リン酸塩の計算による化学種割合(Atlas et al.,1976から)

表7 海水中に存在することが同定されたか確からしい有機リン化合物の例
化合物 化学式(分子量) P
C:N:P モル比
Ribose-5-phosphoric acid (R-5-P)
C5H11O8P (230.12) 13.5 5:_:1
Phospho(enol)pyruvic acid (PEP)
C3H5O6P (168) 18.5 3:_:1
Glyceraldehyde 3-phosphoric acid (G-3-P)
グリセルアルデヒド 3-リン酸
C3H7O6P (170.1) 18.2 3:_:1
Glycerophosphoric acid (gly-3-P)
C3H9O6P (172.1) 18.0 3:_:1
Creatine phosphoric acid (CP)
C4H10N3O5P (211.1) 14.7 4:3:1
Glucose-6-phosphoric acid (glu-6-P)
C6H13O9P (260.14) 11.9 6:_:1
Ribulose-1,5-bisphosphoric acid (RuBP)
C5H6O11P2 (304) 20.4 2.5:_:1
Fructose-1,6-diphosphoric acid (F-1,6-DP)
C6H14O12P2 (340.1) 18.2 3:_:1
Phosphoserine (PS)
C3H8NO6P (185.1) 16.7 3:1:1
Adenosine 5'-triphosphoric acid (ATP)
アデノシン 5'-三リン酸
C10H16N5O13P3 (507.2) 18.3 3.3:1.7:1
Uridylic acid (UMP)
C9H13N2O9P (324.19) 9.6 9:2:1
Uridine-diphosphate-glucose (UDPG)
C15H24N2O17P2 (566.3) 10.9 7.5:1:1
Guanosine 5'-diphosphate-3'-diphosphate (ppGpp)
グアノシン 5'-ニリン酸-3'-ニリン酸
C10H17N5O17P4 (603) 20.6 2.5:1.5:1
Pyridoxal 5-monophosphoric acid (PyMP)
ピリドキサール 5-一リン酸
C8H10NO6P (247.2) 12.5 8:1:1
Nicotinamide adenine dinucleotide phosphate (NADP)
C22H28N2O14 N6P2 (662) 9.4 11:3:1
Ribonucleic acid (RNA)
変動する 〜9.2 〜9.5:4:1
Deoxyribonucleic acid (DNA)
変動する 〜9.5 〜10:4:1
Inositol hexaphosphoric acid, or phytic acid (PA)
C6H18O24P6 (660.1) 28.2 1:_:1
Thiamine pyrophosphate (vitamin B1)
C12H19N4O7 P2S (425) 14.6 6:2:1
Riboflavin 5'-phosphate (vitamin B2-P)
リボフラビン 5'-リン酸
C17H21N4O9 P (456.3) 6.8 17:4:1
Cyanocobalamin (vitamin B12)
C63H88CoN14O14P (1355.42) 2.3 63:14:1
Methylphosphonic acid (MPn)
CH5O3P (96) 32.3 1:_:1
Phosphonoformic acid (FPn)
CH3O5P (126) 24.6 1:_:1
2-aminoethylphosphonic acid (2-AEPn)
C2H8NO4P (141) 22.0 2:1:1
Marine fulvic acid (FA)*
変動する 0.4-0.8 80-100:_:1
Marine humic acid (HA)*
変動する 0.1-0.2 >300:_:1
Phospholipids (PL)
変動する ≦0.4 〜40:1:1
Malathion (Mal)
C9H16O5PS (267) 11.6 9:_:1
“Redfield” phytoplankton
変動する 1-3 106:16:1
Karl and Bjorkman(oの頭に¨)(2002)による。
* 海洋HAとFAは操作的に画分に分けられており、その組成は変動するだろう(数値はNissenbaum,1979による)。HAとFAに伴うリン酸塩は元は結合していた可能性がある。あるいは、金属架橋を通じてHAおよび/またはFAと結びついた無機正リン酸塩の可能性もある(Laarkamp,2000)。