Data for: Observed declines in upper ocean phosphate-to-nitrate availability

Climate warming is increasing ocean stratification, which in turn should decrease the flux of nutrients to the upper ocean. This may slow marine primary productivity, causing cascading effects throughout food webs. However, observing changes in nutrient concentrations at the ocean surface is challenging because they are often below detection limits. The nutricline depth, where nutrient concentrations reach well-detected levels, is related to productivity and indicates upper ocean nutrient availability. Here, we quantified nutricline depths from a global database of observed vertical nitrate and phosphate profiles (1972 - 2022) to assess contemporary trends in global nutrient availability. We found strong evidence that the P-nutricline (phosphacline) is mostly deepening, especially throughout the southern hemisphere, but the N-nutricline (nitracline) remains mostly stable. Earth System Model simulations support the hypothesis that reduced iron stress and increased nitrogen fixation buffe..., , , # Data for: Observed declines in upper ocean phosphate-to-nitrate availability

[https://doi.org/10.5061/dryad.v41ns1s4v](https://doi.org/10.5061/dryad.v41ns1s4v)

Essential files and code for the analyses described in \"Observed declines in upper ocean phosphate-to-nitrate availability\" by Gerace et al.

## Description of the data and file structure

**Dataset_S1:**

* Spreadsheets (the data needs to remain in these spreadsheets for the data analysis scripts to work)
* \"GOSHIP (no3=3)\" is the nutricline depths from GO-SHIP (*1*)  for each unique site and year using thresholds of 3 µmol/kg and 3/16 µmol/kg for nitrate and phosphate, respectively.
* \"GOSHIP (no3=1)\" is the nutricline depths from GO-SHIP for each unique site and year using thresholds of 1 µmol/kg and 1/16 µmol/kg for nitrate and phosphate, respectively.
* \"GOSHIP (no3=5)\" is the nutricline depths from GO-SHIP for each unique site and year using thresholds of 5 µmol/kg and 5/16 µmol/kg for nitrate and phosphate, res...