On the Rocks: Now and Then

It’s the setting, height, and shape that make the rock below an intertidal superstar. This surf zone heavy-hitter sits in an intertidal sweet spot where accessibility and rarely exposed lower reaches find the optimal balance. It’s a leviathan tall enough to support all the intertidal zones, and its steep broad faces impart visibility to the…

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Comparative Photos Show Rocky Intertidal Changes Between 2013 and 2016

With the last bout of sea star wasting syndrome eastern Pacific starfish took a big hit. I describe the progression at this intertidal site in A Peek at Pisaster After Two Years of Sea Star Wasting Syndrome. After three years their numbers are still down. Removal experiments have shown we can expect changes in rocky…

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Recruitment in Barnacles Looks Like This

Last fall this vertical rock wall lay buried under a smothering layer of sand. The resident barnacles, Balanus glandula, couldn’t tolerate it. Winter surf removed the sand revealing empty B. glandula shells and something more; a dense settlement of new recruits. Open space doesn’t stay open long in the in the exposed rocky intertidal. Larvae arrive in…

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Intertidal Boundaries

Just four photos portraying familiar beach and rocky intertidal boundaries. These boundaries frequently serve as frames of reference for my intertidal tales.

Beach Boundaries

A pioneering dunegrass, Elymus, forges down toward the back beach
A pioneering dunegrass, Elymus, forges down off the safety of the foredune onto the backshore
Big waves and high tides push the big wood up into the wrack line
A wrack line forms when king tides and storm surge push all the big wood up onto a shelf on the backshore

Boundaries on the Rocks

A clean boundary between Anthopleura elegantisimma and A. xathogrammica
Boundaries between the anemones Anthopleura elegantissima and A. xathogrammica come and go
Katharina tunicata creates boundaries by maintaining a little open space
In a crowded world, the chiton, Katharina tunicata, creates boundaries by maintaining a little open space

In response to The Daily Post’s weekly photo challenge: “Boundaries.”

In the Rocky Intertidal Change and Stability Look Like This

In the rocky intertidal space is at a premium, so there’s lots of competition for it. Wherever there is competition, there are winners and losers, but disturbance can reset competitive outcomes by creating a clean slate.

A wave-tossed drift log created an opening in a dense barnacle stand
A wave-tossed drift log created this opening in a dense barnacle stand

Ironically, the stability of familiar intertidal communities depends on disturbances that change competitive outcomes.

In response to The Daily Post’s weekly photo challenge: “Change.”

A Peek at Pisaster After Two Years of Sea Star Wasting Syndrome

It’s a good time to check in on the rocky intertidal. All along the west coast sea star wasting syndrome has, to varying degrees, reduced Pisaster ochraceus, a potent predator and organizing force in rocky intertidal communities. Generations of intertidal ecologists, students, fisherpeople and other harvesters, tide poolers, and beachcombers have grown to count on…

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Exploring the Highest Intertidal Fringes

I plan weeks or even months ahead for low tide explorations on the outer shores. The lowest tides, those below 2.0′ below mean lower low water on my home beaches, reveal rocks and sand we hardly ever get to see. On the exposed outer coast, this zone is rarely examined closely because it is usually…

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Finding Yourself in the Infralittoral Fringe

The sandy beaches where surfperch live much of their lives can be vast and featureless.  The sand is constantly on the move so we don’t see plant and animal landmarks indicating the zones so familiar in the rocky intertidal.  In the shot above, could you place yourself with respect to mean lower low water (0.0′…

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