Observed declines in upper ocean phosphate-to-nitrate availability.

ABSTRACT: Climate warming is increasing ocean stratification, which in turn should decrease the nutrient flux to the upper ocean. This may slow marine primary productivity, causing cascading effects throughout food webs. However, observing changes in upper ocean nutrients is challenging because surface concentrations are often below detection limits. We show that the nutricline depth, where nutrient concentrations reach well-detected levels, is tied to productivity and upper ocean nutrient availability. Next, we quantify nutricline depths from a global database of observed vertical nitrate and phosphate profiles to assess contemporary trends in global nutrient availability (1972-2022). We find strong evidence that the P-nutricline (phosphacline) is mostly deepening, especially throughout the souther

SUBMITTER: Gerace SD 

PROVIDER: S-EPMC11831131 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature