Century-scale changes in dissolved oxygen, temperature, and salinity in Puget Sound

Over the last century, many coastal ocean regions have experienced a decrease in dissolved oxygen (DO) concentrations. In this work we consider long term changes in DO in an estuary, which may be influenced by both changing ocean conditions and anthropogenic activity. We analyze nearly 100 years of water column profile data in Puget Sound, a temperate, fjordal, urbanized estuary in Washington State, USA and the southernmost region of the Salish Sea. We observe warming of 1.5°C/century, consistent with warming found throughout the Salish Sea region and similar to coastal ocean and local atmospheric warming. We observe that bottom salinity is increasing at a low rate. Finally, we find that bottom DO is declining at a rate of about 0.6 mg/L/century in Main basin, the largest section of Puget Sound. Changes in DO solubility associated with the observed increase in water temperature can account for approximately 50% of this DO loss. In Puget Sound’s distal terminal inlets where hypoxic condi..., , # Century-scale changes in dissolved oxygen, temperature, and salinity in Puget Sound

Dataset DOI: [10.5061/dryad.v6wwpzh9n](https://doi.org/10.5061/dryad.v6wwpzh9n)

## Description of the data and file structure

Scripts - RUN THESE!

#### File: figure_XX.py

**Description:** figure_02.pyProcesses dataframes and plots manuscript figures.

#### File: figure_functions.py

**Description:** Functions for data and dataframe processing and plotting.

LiveOcean grid attributes (used for plotting and bathymetry)

(MacCready et al., 2021 - see manuscript for full citation; see [https://github.com/parkermac/LO.git](https://github.com/parkermac/LO.git) for public repository)

Note: These files are \"pickle\" data structures. Specific code to load these files are included in figure_XX.py plotting scripts. If loading these files independently, users require Python with the \"pickle\" module.

#### File: plon.p

**Description:** plaid 2D longitude grid (ndarray) for LiveOcean cas7 domain, used for Matp...,