『Abstract
　Burial of fish bones, which consist primarily of hydroxyapatite, has been recognized as a mechanism to remove reactive phosphorus from the oceans. In this study, a new method is presented, which differentiates P associated with biogenous apatite (Pfish) from other P fractions. The method, consisting of a sequential chemical extraction with 2 M NH4Cl, has been successfully tested on standard materials. It enables us, for the first time, to quantify fish debris in sediment records and to assess their importance for the marine phosphorus cycle.
　The NH4Cl extraction has been applied to sediment samples from the Arabian Sea. Preservation of fish debris is significantly higher in sediments located above 1,200 m water depth than it is for deeper sediments. The distribution of Pfish contents in surface sediments is predominantly governed by the extent of fish debris regeneration, which is related to differences in water depth and sedimentation rates. In addition, a good correlation between high sedimentary Pfish contents and low oxygen bottom water concentrations suggests that the presence of the intense oxygen minimum zone may account for the enhanced preservation of fish debris in continental slope sediments.』

Acknowledgments
(Introduction)
Materials and methods
　Sample locations
　Solid-phase analysis
　Sequential extraction analysis
　Fish debris and foraminiferal analyses
Results and discussion
　The NH4Cl extraction: Differentiation between biogenic and authigenic apatite
　Distribution of fish debris in recent Arabian Sea sediments
Conclusions
References

表2.　連続抽出法と抽出リン画分と複数の測定に対する相対誤差

ステップ	抽出剤	抽出されるリン相	相対誤差 （％）	文献
1	●8×25 ml 2M NH4Cl （塩化アンモニウム）（アンモニアでpH 7に調整）、4時間、20℃	●交換性またはゆるく吸着したP （Exchangeable or loosely sorbed P） ●炭酸塩に伴ったP （Carbonate associated P） ●生物起源アパタイト （Biogenic apatite）	＜4	本研究
2	●1×25 ml 0.15M Na-citrate（クエン酸ナトリウム）と0.5M NaHCO3（炭酸水素ナトリウム）と1.125 g Na-dithionite（亜ジチオン酸ナトリウム）、16時間、20℃ ●1×25 ml 2M NH4Cl（pH 7）、2時間 ●1×25 ml demin.water（脱鉱物質水）、2時間	●易還元性または反応性鉄-結合P （Easily reducible or reactive iron-bound P）	＜10	Ruttenberg（1992）に倣う
3	●1×25 ml 1M Na-acetate（酢酸ナトリウム）〔acetic acid（酢酸）でpH 4に緩衝した〕、16時間、20℃ ●1×25 ml 2M NH4Cl（pH 7）、2時間 ●1×25 ml demin.water、2時間	●自生アパタイト （Authigenic apatite）	＜10	Ruttenberg（1992）に倣う
4	●25 ml 1M HCｌ（塩酸）、16時間、20℃ ●1×25 ml demin.water、2時間	●砕屑性アパタイト （Detrital apatite）	＜7	Ruttenberg（1992）
5	●5 ml 6.5 : 2.5 : 1混合物〔HCｌO4（過塩素酸）（60％）＋HNO3（硝酸）（65％）＋H2O〕と5 ml HF（フッ化水素）（40％）、16時間、90℃〔total digestion）全温浸〕	●有機P （Organic P） ●粘土鉱物に吸着したP （P adsorbed to clay minerals）	＜10	Lord（1982）