『Abstract
　Despite intensive research on the different domains of the marine phosphorus (P) cycle during the last decades, frequently discussed open questions still exist especially on controlling factors for the benthic behaviour of P and its general distribution in sediment-pore water systems. Steady state or the internal balance of all relevant physical and (bio)geochemical processes are amongst the key issues. In this study we present and discuss an extended data set from surface sediments recovered from three locations on the NW African continental slope. Pore water data and results from sequential sediment extractions give clear evidence to the well-known close relationship between the benthic cycles of P and iron. Accordingly, most of the dissolved phosphate must have been released by microbially catalyzed reductive dissolution of iron (oxyhydr)oxides. However, rates of release and association of P and iron, respectively, are not directly represented in profiles of element specific sediment compositions. Results from steady-state based transport-reaction modelling suggest that particle mixing due to active bioturbation, or rather a physical net downward transport of P associated to iron (oxyhydr)oxides, is an essential process for the balance of the inspected benthic cycles. This study emphasizes the importance of balancing analytical data for a comprehensive understanding of all processes involved in biogeochemical cycles.』

1. Introduction
2. Materials and methods
　2.1. Study area and sampling sites
　2.2. Sediment and pore water sampling
　2.3. Pore water analyses and flux calculations
　2.4. Solid phase analysis
3. Results
　3.1. Pore water geochemistry
　3.2. Sediment composition
4. Discussion
　4.1. The benthic P and Fe cycle - sources and sinks
　4.2. Examination of the benthic budgets
5. Conclusions
Acknowledgements
References

表1．連続抽出ステップ（Ruttenberg, 1992；Schenau and De Lang, 2000；Latimer et al., 2006による）．各ステップ後に、抽出／洗浄液は遠心分離されて濾過（0.2μm）された．

ステップ	試薬	抽出されたリン成分
（１）生物起源（biogenic）	25 ml 2M NH4Cl（塩化アンモニウム） (pH 7)	交換可能なP（exchangeable P）、生物起源アパタイト（biogenic apatite）、アパタイト先駆鉱物（apatite precursor mineral）、CaCO3結合P（CaCO3-bound P）
（２）Fe3+結合（Fe(III)-bound）	25 ml クエン酸（citrate）亜ジチオン酸（dithionite）バッファー（buffer）（pH 7.5）、 25 ml 2M NH4Cl, 25 ml dem. water（脱鉱物質水）	吸着された還元可能な／反応性のFe3+結合P（adsorbed and reducible/reactive Fe(III)-bound P）
（３）自生（authigenic）	25 ml 1M 酢酸ナトリウム（Na-acetate）（pH 4）、 25 ml 2M NH4Cl, 25 ml dem. water	自生アパタイト（authigenic apatite）
（４）砕屑性（detrital）	25 ml 1M HCl、 25 ml dem. water	砕屑性P（detrital P）
（５）有機結合（organic-bound）	550℃での強熱（ignition）後に 25 ml 1M HCl	有機P（organic P）
（６）オパール結合（opal-bound）	85℃で25 ml 1.5M NaOH	オパールに伴うP（opal-associated P）