『Abstract
　The distribution of silicon isotopes along a meridional transect at 140゜W longitude in the Eastern Equatorial Pacific was used to test the hypothesis that δ³⁰Si of silicic acid in surface waters should correlate with net silica production rates (gross silica production minus silica dissolution) rather than rates of gross silica production due to the opposing Si isotope fractionations associated with silica production and silica dissolution. Variations in δ³⁰Si appeared significantly correlated with net silica production rates in equatorial surface waters and not with gross production rates. Around the Equator, values of δ³⁰Si as low as deep water values occurred in the upper mesopelagic in a zone of net silica dissolution and high detrital biogenic silica content, where the release of low δ³⁰Si silicic acid from opal dissolution would be expected to decrease δ³⁰Si. The δ³⁰Si of the deep water at 140゜W appears constant for depths ＞2000 m and is similar to the deep water at 110゜W. This study brings to light the importance of considering Si fractionation during diatom silica dissolution, the biological fractionation during silica production and physical factors such as currents and mixing with adjacent water masses when interpreting silicon isotope distributions.』

1. Introduction
2. Materials and methods
3. Results
　3.1. Currents system and physical properties
　3.2. Silicic acid concentrations, biogenic silica concentrations and δ³⁰Si
4. Discussion
　4.1. Physical factors: currents and water masses
　4.2. Effect of fractionation during both opal dissolution and Si uptake
5. Conclusion
Acknowledgments
References