See the Seaweeds

As a scientist and curator, learning is a constant endeavor. Mix this with the continuous increase in knowledge about organismal relationships and classification, and training becomes critical to maintaining knowledge necessary to effectively curate collections in the OSU herbarium. Thus, I traveled, sixteen hours by car, to Eagle Hill Field Station in Steuben, Maine at the end of July 2016 to attend two, week-long courses, one of which was “Introduction to Maine Seaweeds: Identification, Ecology, and Ethnobotany.”

My reasons to take a course about seaweeds were two-fold: the OSU herbarium has a very small collection of seaweeds, or macro-algae, and I wanted to add to it. Secondly, I had very little experience collecting seaweeds, and thus sought to learn proper collection and curating techniques.

During the class, we spent about three hours each day collecting seaweeds at low tide. We collected along different types of shorelines near the Field Station.

Shorelines with large rocks and ledges are common near the Field Station (see below). The dark rocks closer to the water are covered with brown rock weeds. Large rock ledges occur at the water’s edge. At low tide near the rock ledges, the water is about chest high. Many different species of seaweeds, especially red algae, occur beneath the water surface attached to the sides of the large rocks. Large brown kelps, such as sugar kelp and winged kelp, are underwater and attached to rocks on the sandy bottom.

A typical rocky shoreline at low tide along the Maine coast near Eagle Hill Field Station.

A typical rocky shoreline at low tide along the Maine coast near Eagle Hill Field Station.

Rock weeds often cover the rocks from the high tide line to almost the water’s edge. The rock weeds are usually of two species: knotted wrack (Ascophyllum nodosum) and bladder wrack (Fucus vesiculosus). Both species are shown in the slide show below. Bladder wrack can be identified by paired air bladders (green bumps on the plant on the left side of the close-up photo of rock weeds). Knotted wrack possesses singularly arranged air bladders along the branches (inflated areas on the plant on the right side of the close-up photo of rock weeds). The creamy white bumps on the rock surfaces are barnacles that cover nearly every rock that receives water at high tide. Pools among the rocks are often havens for red algae, small shrimp, crabs and sand dollars.

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What an incredible experience! Where else could I spend an afternoon clambering over barnacle-covered rocks, poking my hands into pools and crevices looking for red, brown and green seaweed treasures.

A different type of shoreline that we visited is characterized at low tide by open, exposed sandy or gravelly bottoms that often have scattered rocks (see slideshow below). The water is often cloudy, and seaweeds that are attached to rocks beneath the water are difficult to see. The students were often seen strung along the shore, hoping to find a unique specimen in the cloudy water.

After collecting, we began the elaborate task of processing and pressing the seaweeds to create archival specimens by “floating” them onto herbarium paper before drying them in a plant press. On a photo in the slideshow below, one of the students is holding a jug with seawater. We used seawater in the lab to “float” the algae onto the herbarium paper. Tap water is not ever used, as it kills the algae and makes the specimens mushy.

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This is where I leave you until next time. Next time, look forward to meeting some of the seaweeds that I collected, but here is a teaser:

collection sheet of red alga, Devaleraea ramentacea

A collection of the red alga, Devaleraea ramentacea.

Above, each individual alga was “floated” and arranged on a herbarium sheet before drying in a plant press. The specimen was found underwater attached to rocky ledges that were partly exposed at low tide. I collected this alga by reaching underwater and feeling along a rock, choosing it because it felt different than the other algae around it. This species has a limited native distribution, found only along the northern Atlantic coast from Cape Cod to Labrador and Newfoundland.

About the Author:  Dr. Cynthia Dassler is curator of Cryptogams (small plants that produce spores) at The Ohio State Herbarium (OS) in the Department of Evolution, Ecology and Organismal Biology.

All photos were taken by Nick Blouin.

 

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