Atlas

Atlas of  Oceanographic Conditions in the  Strait of Georgia

CTD station

A beautiful day out on the Strait. Ready for sampling: CTD at left, Tablet sitting on the gunwhale, and water sampling gear on the deck at right, with coolers ready for sample storage.

Water samples ready for analysis

Water samples from the Spring Bloom in 2021: nutrient vials in front,  preserved phytoplankton at right,  biotoxin assays (new!) at left. Log sheet in foreground.

Stormy weather!

It is not always calm and sunny when CitSci sampling is being carried out.

CTD profiling

Using the manual downrigger as a winch to lower the CTD

A jar full of zooplankton

The contents of a zooplankton net. Always fun to look at!

Secchi Depths

How clear is the water? Lowering the Secchi disk.

Welcome to the Atlas of Oceanographic Conditions in the Strait of Georgia, based on the Pacific Salmon Foundation's Citizen Science Dataset. The "PSF CitSci" Program visits about 60 locations in the Strait roughly 20 times a year to measure a variety of ocean properties, resulting in around 1000 stations sampled every year.  Additional information in the atlas comes from stations sampled by the Hakai Institute (in the far northern Strait of Georgia) and the zooplankton archive of Fisheries and Oceans Canada.

Oceanographic information about the Strait of Georgia in this atlas is divided into different sections concentrating on Hydrography (temperature, salinity, dissolved oxygen content, and total chlorophyll), Nutrients (the major macronutrients that support plant life in the Strait), Harmful Algae, and Zooplankton.

 

 

Key Figures

Oceanographic stations in the Strait of Georgia from the CitSci and other programs

PSF CitSci station locations, as well as other sources of oceanographic data for the Strait of Georgia. Track plans for each patrol are shown in red. All stations along the track have hydrographic profiles using a conductivity-temperature-depth (CTD) probe, "Full" stations also include water sampling for nutrients, and "busy" stations also include both nutrients, chlorophyll, and phytoplankton sampling.

a) Fraser River inflow b) surface temperature c) surface salinity d) surface dissolved oxygen e) Chlorophyll biomass (vertical bars show spring bloom timing from other programs) f) surface nitrate g) surface silicate h) surface phosphate

Mean near-surface conditions for the Strait of Georgia since 2015.  This figure summarizes thousands of stations, the combined efforts of dozens of people over many years.

Recently, higher river flows are reflected in lower surface salinities. Summer silicate concentrations are also noticeably higher. Planktonic biomass (Chlorophyll) can vary greatly from year to year.

a) Temperature in upper 150m of the Strait. b) Salinity. c) Dissolved Oxygen. d) Chlorophyll (note logarithmic depth scale)

Mean conditions at all depths for the Strait of Georgia. White lines in upper row indicate temperatures of 17ºC, above which salmonids show stress, and in the third row O2 concentrations of 187 μM (or 6ppm), below which salmonids show stress. They are squeezed into a narrow depth range in late summer!

Deeper waters were somewhat warmer (and slightly fresher) in 2015 and 2016 in the aftermath of the marine heatwave known as the "Pacific Blob".

Heterosigma akashiwo

Time series for the Harmful Algae Heterosigma akashiwo since 2015. A particularly large bloom over the whole Strait occurring in June 2018 was associated with the death of 250,000 fish at 2 fish farms in Jervis Inlet.

To take a closer look at the regional and seasonal variation, interannual variation and methods, follow the thumbnails below for Hydrography, Nutrients, Harmful Algae, and Zooplankton data.