Saturday, May 10, 2014

Billions and billions

Boundary Bay was in a quiet mood when we dropped in a couple of days ago. The tide was partway out, and didn't seem to be either coming or going. Though the sunshine was bright, there was a chilly wind, and the beach was almost deserted. A couple of boats were tied high and dry on the sand. There were no paddle boarders, no dog walkers, barely even any birds. Sand, stones, seaweed, and water; that was all there was to see.

Looking back towards Burnaby. One wader.

It all depends on your perspective. That beach is crowded, almost to capacity. A few hundred people, a dozen dogs, some flocks of birds; what are they but a passing trick of the weather to the billions and billions of living creatures that call it home.

From our usual parking spot at the Beach Grove boat launch, we walked south, towards the US border. Underfoot, on the sand, snails and hermits were making tracks.

Popular resting spot.
The stones in this section, where the currents are not too strong, so that even the small pebbles don't roll around like they do on the White Rock beach, are all coated with barnacles. In more agitated waters,barnacle babies may settle on any surface, but they don't survive unless their new home stays put.

Sea lettuce, about two inches deep, so very green, a super-concentrated springtime yellow-green. In the background, barnacle-laden stones, and another boat launch, covered in green scum.

Near the border, a couple of old logs broke the monotony of sand and stones. A small city, divided into residential districts: on the outer surfaces, sea lettuce, barnacles and mussels; in the dark crevices, more mussels, dotted with tiny white barnacles, and teeming masses of hermits in mudsnail shells; underneath, where the water stays even at low tide, the mudsnails, tiny crabs, and amphipods.

Near the top of the larger log. Medium-sized barnacles, and polka-dotted blue mussels. The dots are tinier barnacles.

Smiling stump. The flash revealed a thick coating of critters in the rotted centre.

Back at the boat ramp, I sat on the clean cement to examine a nearby rock.

Small barnacles, tiny hermit crabs (3), 3 snails, patches of egg mass, species unidentified, a flatworm, and under and around it all tiny, pinhead barnacles. The babies that wouldn't survive rolling.

Another look at those hermits, barely visible peeking out of their little shells, periwinkle and nassa.

A flatworm. There were many on this rock. At the bottom, tar spot seaweed, and a green worm.

More tar spot seaweed, a flatworm family, and that two-toned worm. It's a green ribbon worm, Emplectonema gracile. It eats mainly barnacles.

About that tar spot seaweed. It is an encrusting phase of the pretty Turkish towel that I bring home for my hermit crabs to climb on. In this phase, it coats rocks, and looks like tar or black oil. In this stage it is producing spores. As a red blade, it produces gametes (sperm and eggs).

Mastocarpus papillatus is an interesting seaweed species with two distinct lifecycle phases.  It has a long-lived "tetrasporophyte" phase, which looks like a crust or dried tar spot on rocks, with colors ranging from reddish-brown to black.  Each year, a new "gametophyte" phase grows from the "tar spot", known in some areas as "Turkish washcloth". . . . The female plants are covered with papillae - short, bumpy or nipple-like outgrowths which are the sites of fertilization.  . . . The male gametophyte has no papillae, is yellowish to light pink or light rose, and has a thinner blade.  The spore producing tar spot phase of Mastocarpus papillatus is a slow growing, long lived perennial (one source estimates up to 90 years).  The female and male bladed gametophyte phase dies back every year leaving just the encrusting "tar spot".   . . .  It grows on rocks, it can undergo considerable desiccation, and can withstand high temperatures.
From Seaweed Industry Association.

1 comment:

  1. fascinating! I love your posts like this, make me want to drive to the nearest seashore and explore.


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