Marine Data Products

Citizen Monitoring
Profiles
Time Series

ORCA Buoy
Profiles
Time Series

MMP Profiler + ADCP

Historical Comparisons

Comparative Cross-Sections

Freshwater & Terrestrial Data Products

Freshwater Sampling

Land Use

Geology

Marine Life Studies

Diver Observations

Bloom & Fish Kill Observations

Data Access

Marine Overview

In order to identify the potential natural and anthropogenic factors that may be contributing to Hood Canal’s severely depleted oxygen levels, the Hood Canal Dissolved Oxygen Program (HCDOP) must understand how Hood Canal’s marine waters vary, over what timescales, and therefore, assess what factors may be driving the variation.

Water characteristics, such as temperature, salinity, oxygen, and nutrients, in an estuary, such as Hood Canal, are affected by processes in the watershed, by local climate, and by the waters outside Hood Canal coming in from Puget Sound, the Strait of Juan de Fuca, and ultimately the Pacific Ocean. The oceanic waters also reflect effects from global weather patterns, such as El Nino-Southern Oscillation and the Pacific Decadal Oscillation. It is very complex since so many factors are involved.

Moreover, oxygen is affected by several physical and biological factors. Deep water oxygen concentrations are affected by the productivity of the algae, which ultimately is respired in the deep waters, consuming oxygen. But the deep water oxygen concentrations are also affected by physical processes like the circulation of the water (how long the water is in the canal before being flushed) and the stratification of the water (how resistant the water is to mixing with the surface waters). The relative contribution of these factors and also what role humans may be playing (such as, adding nutrients, changing the delivery of freshwater) is not known. However, these various processes can be studied through a combination of measurements and modeling in the marine waters coupled to the inputs from the watershed [link to watershed overview].

The HCDOP currently employs four interrelated strategies in its effort to identify the driving mechanisms responsible for the canal’s low dissolved oxygen levels:

a) Monitoring of the present-day water properties in the canal, via profiles and time-series, taken by both citizen volunteers and by moorings with near real-time data transmission.
b) Measurement using a moored profiler of the upward fluxes of the deep water, which contains nutrients, to the surface waters where the algae live. The deep waters in Hood Canal have a high nutrient content, both from their source from the ocean and due to local particle settlement and demineralization.
c) Evaluation of historical data comparisons of recent data and data from the 1950’s and 1960’s comparing oxygen inventories and cross-sections of marine data over the seasons and years.
d) Implementation of an integrated hydrodynamic and aquatic biogeochemical cycling model designed to simulate water and chemical fluxes through the canal, taking inputs from the watershed model and from a weather model.