Between March 5 and 11, 2012 a number of significant intrusions were detected at the Central Strait of Georgia site (300 m). As in past years, we occasionally capture the late-winter passage of cold, dense intrusions flowing down-slope into the deeper recesses of the strait. This density current picks up sediment and its arrival is seen here in the turbidity signal from March 7.

Acoustic Doppler Current Profilers (ADCPs) are instruments used in our subsea network and other oceanographic applications to measure the currents. We collect data from two types of ADCPs, manufactured by Nortek and RDI. These ADCPs use “sound beams” to measure water movement. Sound pulses are sent out in three or four different directions from the instrument; when sound waves strike suspended objects such as tiny particles or zooplankton, some of the energy is reflected back to the ADCP where it is detected by the instrument’s transducers. The received signal intensity gives an indication of the abundance of particles within the water. The Doppler shift of the received signal for each beam is used to determine the current velocity.

A colony of squat lobsters (Munida quadrispina) in Saanich Inlet captured on camera during the VENUS cruise in the fall 2011 at a depth of 96 m.

An upward-looking echosounder was deployed in Saanich Inlet on 3 July 2011. The instrument was part of an “autonomous” (i.e., battery-powered, internally-recording) package of instruments that filled in for the usual cabled instruments while the Saanich communications node was out of the water for three months for a scheduled upgrade.

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Although we have been collecting Acoustic Doppler Current Profiler (ADCP) data for over two years from various locations in the Strait of Georgia, real-time plots of the data have only recently been added to the Data Plots section. Shown here is a single day of data from the Eastern Strait of Georgia site, showing (top panel) the East/West component, (second panel) the North/South component, (third panel) the Up/Down (vertical) component, and (forth panel) the average back-scatter intensity.

Dynamic sediments and sediments with active biogeochemistry often generate a variety of chemical compounds, some of which will be gaseous. This inverted echo-sounder image from October 30, 2011 at the Delta Dynamics Laboratory in the Strait of Georgia at 108m water depth near the mouth of the Fraser River has captured numerous clouds of rising bubbles.

The Zooplankton Acoustic Profiler (ZAP) located at the base of the slope of the Fraser Delta recorded this hourly image of echo-sounder data on September 5, 2011 ( just after dusk and at rising tide). The image reveals a dense school of large fish between 10 and 20m depth, and many individual fish between 20 and 80m depth.

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We now offer our ASL Zooplankton Acoustic Profiler (ZAP) echosounder data in MATLAB Version 7 mat files and PNG/PDF plots (the same daily 30 second average plots from our data plots pages. Vist our Download Data page and select “Search by Instrument” to access these new formats.

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On April 30, 2011 an abrupt hydrographic “front” crossed the VENUS Central Strait of Georgia site. The temperature (red) dropped 0.6 degree and the Oxygen concentration (magenta) nearly doubled. The 0.6 C temperature drop occurred between two samples taken one minute apart! This cold front was accompanied by a sharp increase in the dissolved Oxygen concentration, rising from 2.8 ml/l to 4.4 ml/l. There was, rather surprisingly, little salinity (green) change associated with the arrival of this water mass, although the salinity had started dropping slightly on May 29. A density increase (blue line) at the front is attributed entirely to the colder temperatures.

This image was captured from the Strait of Georgia Webcam video feed at 300 m depth. The spotted ratfish, Hydrolagus colliei, is a cartilaginous fish related to sharks and rays, and is the only species in its subclass found off British Columbia.

A juvenile giant Pacific octopus, Enteroctopus dofleini, pounces on a passing tanner crab, Chionoecetes bairdi. Once the crab is secured the octopus retreats and will consume its meal in the safety of its den. E. dofleini is a stealth predator that primarily eats crustaceans, other mollusks and fish. This video was captured on the Strait of Georgia webcam at 300m depth.

This East Pacific Red Octopus (Octopus rubescens) was observed by our camera in Saanich Inlet. This octopus is found from the southern Gulf of California to the Gulf of Alaska. O. rubescens generally grows to a mantle length of 8-10 cm and up to 400 gm.

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From the outside, it may have appeared that not much was happening with NEPTUNE Canada last fall. But those were busy days, as we worked through a plethora of tasks required to commission our infrastructure, instruments, security provisions and data products.

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A shortspine thornyhead, Sebastolobus alascanus, swims past the new webcam in the Strait of Georgia at 300 m.