An icy ocean wonderland to explore

Walking on the ice past a mooring buoy, Jan. 25
Walking on the ice past a mooring buoy, Jan. 25

We’ve had quite a long cold snap, and the ocean ice in and near our inlet is way over 6 inches thickness, the recommended thickness for safety.  Beautifully smooth too, in places, though the wind chill discouraged us from going back for our skates.

A branch which has been stuck in the ice for weeks now
A branch which has been stuck in the ice for weeks now, next to a mooring buoy, with other moorings in the background
We walked out to a small island and explored the ice formations around the rocks
We walked out to a small island and explored the ice formations around the rocks
Along the shoreline at low tide, a weird and wonderful landscape to explore
Along the shoreline at low tide, a weird and wonderful landscape to explore

At low tide, the ice is sitting on or near the bottom, so there’s little risk. It’s harder to get onto the ice when the tide is higher, as the broken pieces around the edge may not bear one’s weight, as my son learned this morning! No harm done, just wet boots and an uncomfortable trot home.

These rocks are just underwater at high tide, and we have to avoid them when rowing or paddling in the summer.
The big rocks in the middle are barely underwater at high tide, and we have to avoid them when rowing or paddling in the summer.

The edge of the ice

The tidal inlet on January 2, 2009
The tidal inlet on January 2, 2009

Ice always builds up and stays in the inlets where it isn’t easily carried out to sea.  At low tide it just sits on the bottom, on the mud. There’s always a dynamic edge out there forming, melting, breaking off depending on the wave action, with pieces getting carried out to sea.

Ice on the water’s edge on Mahone Bay

The water's edge, tide rising after a cold night
The water's edge, tide rising after a cold night
The ice that was shaped by this rock and then broke as the tide fell tide now floats over it on the rising tide.
The ice that was shaped by this rock and then broke as the tide fell tide now floats over it on the rising tide.

I tasted the ice that had formed at the water’s edge on a small beach, as I said I would. As predicted, it was indeed fresh, not salty.  A good survival tip, should you ever find yourself shipwrecked on a desert island in winter.

Ice on salt water

Ice crystals forming
Ice crystals forming

People are sometimes surprised to learn that ocean water can freeze (but think about it: we’re worried about the melting polar ice cap).  Two winters out of the last four, we’ve been able to skate on Mahone Bay after a really cold snap.  Salt water freezes at a lower temperature than fresh water, and the saltier it is, the colder it has to be to freeze.  I’ve found that it has a softer quality than freshwater ice, perhaps because of the impurities it would contain.  But I’m sure it’s just as unforgiving if you crack your head on it!

I’ve always found crystals fascinating. In my days as a lab chemist I enjoyed doing crystallization, which is done in the lab as a means of purifying a substance.  That’s because a crystal is formed when the molecules of a substance lock together in a close pattern.  There isn’t much room for anything else in there, between the molecules.  Separate the crystals from the rest, and you’ve got a pretty pure product.

Ice on a rock as the tide recedes
Ice on a rock as the tide recedes
This morning there were water crystals forming in quiet corners of the bay.  They are supposed to contain very little salt.  (Next time I’ll try tasting some!)  When salt water freezes on the surface, the ice is relatively fresh (i.e. not salty).  Polar bears are observed (not in Nova Scotia!) drinking from puddles on ice floes.  Meanwhile, the water beneath the ice gets saltier – and denser, sinking – which makes it even less likely to freeze.

Of course, these ice crystals I saw this morning melted during the day.

Watching the changes in the ice on the bay is one of the joys of living in Nova Scotia in winter.

If you want to read more about the science of seawater freezing, see the Water Encyclopedia.

Ducks eating on marsh at high tide

What are the ducks eating?
What are the ducks eating?

I wonder what the ducks are finding to eat in the flooded marsh? At high tide, a dozen of them will be gathered around one spot, head and neck down in the ooze.  Is it some small semi terrestrial creature that gets flooded out when the tide is so high?  Does anyone know?