Wednesday, August 20, 2014

1,2,3 Red Light

Red tide on Salish Sea - photo by Joseph Blackburn
For anyone looking out over the ocean this past month and wondering if there had been some kind of a mass slaughter taking place they wouldn't have been alone in their thinking.  A massive red tide that quite literally turns large patches of the ocean into the colour red seems to have been lingering all over Georgia Strait & Howe Sound, otherwise known as the Salish Sea, for most of July and it can probably be connected to the nice warm weather we've also been experiencing.  But rather than the ocean hemorraging blood it's actually an algae bloom caused by a species of marine plankton known as dinoflagellates.

These blooms happen when the reddish brown algae starts growing and accumulating too quickly in the water, and their sheer numbers produce a discolouration of the water. These algae blooms occur around the world for different reasons including; chemical run-off from agricultural activities, iron rich dust blowing off coastal deserts, and seasonal up-wellings of ocean currents which is what happens in our waters every summer, and in each case it means there are lots of nutrients for the algae to feast on. While on the one hand the presence of so many organisms can deplete the oxygen levels to the extent other creatures have to leave the area or die, these marine plankton are also an important source of food in the marine ecosystem. 

There are many different kinds of dinoflagellets but in our part of the world they are mainly either blue or red. The blue ones are harmless and produce the bio-luminescence you can see in the summer nights whenever the water is stirred up. (see link to previous blog post for more information

The red ones on the other hand produce a paralytic neuro-toxin known as saxitoxin that is inadvertently ingested by shellfish such as mussels, clams, oysters, and scallops.  Like all bivalve molluscs, they are filter feeders and, as they filter the ocean water for plankton and algae to eat, (in the case of oysters up to 5 litres per hour) the toxin is absorbed in the digestive process and remains in their bodies for several weeks. 

Typical bi-valve
While the saxitoxin doesn't harm the shellfish, it can cause paralytic shellfish poisoning in humans if they eat shellfish that have this toxin still in their system. The toxin is water-insoluble, heat and acid-stable, and ordinary cooking methods do not eliminate it.  Some shellfish can store this toxin for several weeks after a harmful algal bloom passes, but others, such as butter clams, have been known to store the toxin for up to two years. 

Paralytic shellfish poisoning is one of four types of shellfish poisoning and is the most deadly. In mild cases of PSP there may be tingling or numbness around lips (spreading to face and neck), headache, nausea, vomiting and diarrhoea . In more extreme cases there could be muscular paralysis and respiratory difficulty, potentially resulting in death due to respiratory paralysis two to twenty four hours after ingestion. When you see red tide in the ocean think 1, 2, 3 red light before eating any shellfish.
Red tide in English Bay - photo by Junie Quiroga

Friday, August 8, 2014

Boys Of Summer

Waiting for the slide to open - photo by Junie Quiroga
Ever since Tom Sawyer and Huck Finn decided to take off on a raft down the Mississippi for pure fun and adventure boys have been drawn to floating things on the water.  Even when they grow up they can't seem to lose that feeling of freedom they get when they are out there breaking the rules of convention and getting wet. The lure of distant objects is even more inviting when it's early morning and nobody is really watching what's going on.

Bruce on his paddleboard - photo by Junie Quiroga
First stop is the Q41 navigational buoy which is there to advise boaters they need to be on the other side and away from shore where hidden rocks pose a hazard to their boats and their boats pose a hazard to the swimmers. The Q41 buoy is also a favourite resting place for the resident pair of bald eagles who use it as a place to keep an eye on things and have their brunch. The Q41 buoy is also where I like to swim to first thing in the morning to check out the currents and decide on my swimming route.

Nelson & Dennis on Q41 buoy - photo by Junie Quiroga
Next stop of course is the fireworks barge where, in spite of warning signs to stay clear, the temptation to climb up and check out what goes on behind the scenes is too much to resist. But the signs don't have any time of day restrictions printed on them and they even provided a handy ladder for climbing up so what's a boy to do?  Well there's only one thing more exciting than climbing up a barge and that's the thrill of jumping off it.

Dennis & Nelson on the fireworks barge - photos by Junie Quiroga

Even the seals were amused as they watched us from below and wished they could have climbed up themselves.  Nothing was disturbed, nobody got injured, and it was all good fun. Once again, for a little while, we could forget about being all grown up and having to go to work and just enjoy being a summer boy again.

Nelson swimming in English Bay - photo by Junie Quiroga