nichepoetryandprose

poetry and prose about place

exploring the intertidal zone

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Every summer, we take a day to drive along the Bay of Fundy and explore some of the beaches and rocky shores.  Last summer, we found a small cove where the fog was just lifting. 

Through the mist we could see the ghostly form of a fishing weir and the distant rugged shore. 

a cove along the Bay of Fundy coast

The beach was pebbles and sand, perfect for beach-combing.  We wandered at random, watching for sea glass, shells and wave-smoothed rocks. 

The intertidal area, between low and high tide, is an extraordinary space, not quite ocean, not quite land.  The plants and animals who live in this area have very particular ‘niche-needs’.  They need the rise and fall of the tide twice daily.  Some plants have adaptations to help them cope with changing conditions.  For example, the brown algae Ascophyllum nodosum has bladders to help it float at high tide and reach the sunlight.   

When we explored the cove, it was low tide.  Where the sea water was trapped among the rocks, there were tidal pools, small natural aquariums of sea life.  One rock with a large hollow in its surface had its own population of bladder wrack (Fucus vesiculosis), green algae (Enteromorpha), barnacles, and a lone crab. 

The barnacles are fun to watch.  They are crustaceans, and live with their shells securely attatched to the substrate.  An opening in the top of the shell is covered by a pair of  ‘sliding doors’ called the operculum.  Under water, the operculum opens and the barnacle reaches out with modified legs, designed to capture its food.  The legs, known as cirri,  look like feathery fingers, reaching out and pulling back, reaching out and pulling back.  

The ‘niche’ of a particular plant or animal can be thought of as its ‘occupation’ in the space where it lives.  For example, with respect to food gathering, the crab feeds on the larger prey in the pool, the barnacles filter out the smallest creatures, and the algae take in their nutrients from the water itself.  Although they live in the same space, the crab, barnacles and algae each occupy a different ‘niche’.

one of the smallest tidal pools ever... in the hollow of a rock

 

Deep Cove detail

low tide

weirs and dories indistinct

pillars of fog

glide up the long beach

attention to

drifts of mica

periwinkle paths

breaking bands of wave

water kicked into rainbows

sunlight above the fog

plover tracks sprinkled on sand

cobbles, coloured glass

float ropes, plastic pink

rockweed

plaited by the sea

© Jane Tims

Written by jane tims

August 5, 2011 at 7:02 am

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