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# Gulf of Alaska Coastal Water Transport Pathways and Implications for Ecosystem Response

## Details

**Authors** Élise Beaudin, Emanuele Di Lorenzo, Mara A. Freilich, Arthur J. Miller

**Year** 2026

**Publisher** Journal of Physical Oceanography

**Kind of work** article

**Discipline** Oceanography

**Secondary disciplines** Climatology

[Read it at the publisher](https://doi.org/10.1175/jpo-d-26-0059.1) 
10.1175/jpo-d-26-0059.1

## In authors' words

### Abstract

The Alaska subpolar gyre is a high-nutrient, low-chlorophyll system in which offshore productivity depends on exchange with iron- and macronutrient-rich coastal waters. Mesoscale eddies are the primary mechanism for export of nutrient-rich coastal waters offshore, and their formation is strongly linked to large-scale atmospheric forcing associated with the Aleutian Low (AL), which seasonally modulates regional wind stress, circulation, and eddy generation. Recent marine heatwaves, including the 2013–14 Blob, the 2015–16 El Niño, and the 2019 Alaska heatwave, were associated with distinct climate anomalies that altered atmospheric circulation and modulated the AL, raising questions about how coastal export responds to prolonged climate extremes. Here, we examine variability in Gulf of Alaska coastal transport pathways over 1993–2025, using Lagrangian particle tracking in a high-resolution ocean reanalysis product. We identify three dominant pathways: transport along the mean gyre circulation, offshore export via mesoscale eddies, and coastal retention. Variability in these pathways is primarily linked to atmospheric sea level pressure, local wind stress and wind stress curl, and eddy kinetic energy. Despite weakened circulation and reduced eddy formation during the prolonged marine heatwave conditions between 2013 and 2019, offshore export through the eddy pathway persisted and even periodically intensified during El Niño events. In contrast, transport along the mean gyre circulation declined significantly. These findings suggest that the reorganization of ocean transport pathways can act as a dynamic resilience mechanism for ecosystem response during such extreme conditions.

### What they set out to do (purpose)

To examine how the pathways by which nutrient-rich coastal waters are exported into the offshore Gulf of Alaska subpolar gyre vary over three decades, especially during recent prolonged marine heatwaves.

### Who or what was studied (sample)

A 1993-2025 high-resolution ocean reanalysis of the Gulf of Alaska.

### How they did it (methods)

Lagrangian particle-tracking analysis of a high-resolution ocean reanalysis product, identifying and comparing three coastal transport pathways (mean gyre circulation, mesoscale-eddy export, coastal retention) against atmospheric forcing indices.

### What they found (results)

During the 2013-2019 marine heatwave period, transport along the mean gyre circulation declined significantly, but offshore nutrient export via mesoscale eddies persisted and even intensified during El Niño events, indicating that reorganization among transport pathways acts as a resilience mechanism for ecosystem nutrient supply.

## Commentary

### In short

The finding shows that the offshore ecosystem's nutrient supply depends on relationships between atmospheric forcing and multiple transport pathways, and that the whole transport system can reorganize which pathway dominates in order to preserve its function under stress.

**Patterns it shows** S, R

**Added** 2026-09-13

**How to cite this** Élise Beaudin, Emanuele Di Lorenzo, Mara A. Freilich, Arthur J. Miller (2026). Gulf of Alaska Coastal Water Transport Pathways and Implications for Ecosystem Response. Journal of Physical Oceanography.