Visiting Benjamin and North Islands

By sheer good luck, our little kayak excursion to Benjamin and North islands happened to coincide with the only three consecutive days of sunshine in late-mid July. Sometimes happiness is sun, flat water, good company, and no pesky bugs. Really! No bugs!

There were three of us, all taking much pleasure in poking around on shores and in forest, just looking to see what we could see. And there was plenty for curious naturalists to find and contemplate.

Humpback whales were cruising around on all sides, and the whoosh of their breathing was a frequent backdrop. Sometimes there was a honking sound along with the breath, and we wondered if that was some kind of communication or if it was inadvertent, like a snore. A small group of juvenile sea lions attended us, popping up in close-packed unison on one side and then on the other, staring and snorting, apparently very curious. There was only one sea lion on the traditional haulout rock; it looked rather thin and unwell. A little pod of orcas foraged around a rocky point, and we were pleased to see two very small babies, along with two females and a ‘teenager’.

Pigeon guillemot. Photo by Katherine Hocker

Adult pigeon guillemots were common, floating and diving, and making short flights that showed off their flashy red feet. We saw no juveniles, however, so the chicks were presumably still lurking in their cliff-crevice nests. A few marbled murrelets, including one juvenile, whistled and dove, and we also tentatively identified an ancient murrelet.

Pink salmon were jumping, and an unwary pink was lugged by a parent eagle to a nest, where noisy nestlings expressed their appreciation. Another eagle caught a large, unidentified fish, breast-stroked with it to a rock, stood on the still-flopping fish for a while, and eventually toted it off into the forest.

Choruses of shrieking oystercatchers indicated their frequent displeasure at some disturbance—by others of the same species, or by an overhead eagle, or whatever. One pair of oystercatchers dive-bombed a rock-perched eagle, bedeviling it until it gave up and retreated to the trees. Another pair of oystercatchers guarded two big, fuzzy chicks that made themselves ‘invisible’ by creeping in between shoreside boulders.

A rocky ledge held a crowd of gulls of various sorts, among which we spotted several black-legged kittiwakes, perhaps wandering over from Glacier Bay. Their short, black legs and long, black-tipped wings made them readily distinguishable from the ordinary gulls. Scattered along the mussel beds we saw several black turnstones, already headed south, apparently, and a lesser yellowlegs. Squadrons of harlequin ducks scuttled along the rocky shores, getting away from us as fast as possible without flying. Most of these were in female plumage and might have been some of this year’s young.

Patches of bright yellow-green seaweed caught our eye; they were especially vivid when seen through sunglasses. These turned out to be ‘sea-sacs’, hollow, finger-like algae at about the mid intertidal level. We later learned that, although this species is technically a red alga, it turns eye-smiting yellow-green when mature. Water oozes in and out of a small hole at the tip. Sometimes amphipods chew holes at one end of the tube and crawl into a ready-made protective house.

We hauled out on a beach for a snack and a stretch, and amused ourselves for a while by sorting pebbles. Here is a pile of the pretty-colored ones, or the super-smooth ones, or the ones with especially nice patterns or shapes. Just like kindergartners! But it got too hot in the sun–even the stones were distinctly hot to the touch—so we retreated to our boats and to more mature considerations, such as Should we have afternoon tea now or later?

Our camp was in a well-used site above a wide beach. Considering how much use this place gets, there was very little trash left lying about; we only filled about half of a big, yellow litter bag. However, there are limits to what we’ll pick up, and we were sorry to see that some recent campers clearly had no idea about proper camp sanitation and courtesy to subsequent campers.

Among the found objects on the beach was part of the well-cleaned head of a fish—probably a flatfish of some sort. Only a lower jaw and some flat plates were still linked together, and the jaw had several rows of small, curved teeth and a little bony spur at the front end. All three of us are profoundly ignorant about the functional anatomy of fishes, but we enjoyed our small deductive exercise in arriving at a guess that it came from a halibut.

Perhaps it doesn’t take much to engage the attentions of curious-minded folks! But what fun!

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Looking at intertidal algae

The tide was moderately low, a minus 3.9 or so, and four of us had the privilege of tagging along with a genial visiting algologist (technically a phycologist) on a stroll through the intertidal zone. As true neophytes (the word literally means ‘new plant’!), we hoped to learn to identify a few of the common intertidal algae. Knowing the name of an organism is just a beginning: if you know the name, then you can probably look it up and find out a bit more about its natural history. A name in a vacuum isn’t very interesting!

We ambled across rocks and mudflats as the Latin scientific names (along with identification cues) were dropping thick and fast. One of us took notes, rendering the names phonetically—to be corrected later, along with brief tidbits of natural history—to be amplified later. So we had home work to do (as did the algologist, whose specimen bag was getting fat).

There are thousands of species of algae, ranging in size from microscopic one-celled kinds to giant meters-long kelps, and ranging in form from strings and ropes, to bristly mats and dainty frills, to hefty blades, to bubbles and blobs, and everything in between. Their life histories are equally varied, spurring me to contemplate a future essay on what is called ‘alternation of generations’, something that is characteristic of many plants but not found in animals.

In the meantime, here is a tiny sample of our finds on this excursion—the ones we found most readily distinctive.

–Sea cauliflower (a.k.a. sea potato or brain seaweed). Leathesia marina, classified as a brown alga. This is a lumpy, spongy, yellowish-brown alga, hollow except when quite young; when this blob is squeezed, it breaks apart into filaments, not mush. It is an annual plant (meaning that it does not live from year to year) in the mid to low intertidal zone. It often grows as an epiphyte on other species of algae, but it also grows on rock. The visible blob produces spores that germinate into tiny egg- and sperm-producing plants; when a sperm fertilizes an egg, the resulting zygote grows into the spore-producing blob. The alternation of a spore-producing plant with a gamete-producing plant in the life cycle is the basis for the term ‘alternation of generations.’ One research study found that mortality increased when the plants were crowded and when wave action became too severe. This is one of several species of alga that have antiviral properties and therefore some medicinal value for humans.

Studded sea balloons. Photo by Kerry Howard

–studded sea balloons. Soranthera ulvoidea, classified as a brown alga. The ‘balloons’ are pale brownish sacs up to about two inches long. The surface is studded with darker pimples, which indicate locations of spore formation. As in the sea cauliflower, the spore-producing individual grows from a fertilized egg on a small plant in the alternate portion of the life cycle. This species is an annual that only grows as an epiphyte on other algae of two particular genera. A researcher investigated the possible consequences of this epiphyte on the host, and found that the presence of the epiphyte increased the drag (caused by water currents) on the host and tended to make the host detach from its substrate (which is generally lethal to the host), but sometimes the epiphyte detached first, and no harm came to the host. Indeed, it seems that the presence of the epiphyte reduced grazing on the host by amphipods, which preferred to eat the epiphyte.

Sea sacs

–sea sacs (Halosaccion glandiformis), classified as a red alga. The long, slender, thin-walled, finger-like sacs are reddish-purple when young but bleach to brownish-yellow as they age during the summer, before dying back in the fall. Each sac is perforated with tiny pores that let in sea water. The sacs fill with water except for a gas bubble at the tip. When exposed to air, the sacs lose water by evaporation and through the pores, while surface tension at the pores prevents entry of air. A good supply of internal water allows the sacs to survive exposure to air longer than if the sacs are empty; photosynthesis (the process by which carbon dioxide and water are converted to carbohydrates and oxygen) can be conducted using carbon dioxide from the contained water. If a small hole develops at the base of a sac, little amphipods and worms may crawl in and use it for a refuge.

The visible sac may be a male or a ‘tetrasporophyte’ that developed on a microscopic female. The tetrasporophyte puts out spores in groups of four (hence the ‘tetra’), two males and two females. The females are mature sexually at a very young age. They catch non-motile sperm on special hairs, and the resulting zygotes develop into a new tetrasporophyte, while the tiny female disappears. The sources of sperm for the zygote are males of the previous generation, because the males produced at the same time as these females are not yet mature. A research study showed that the spores settle and germinate best on surfaces that are rough at a micro-scale, rather than on smooth surfaces.

Thanks to Dr. Sandra Lindstrom for a good field trip and Dr. Mandy Lindeberg for additional instruction.

Note: these algae, like many others, have had numerous common and scientific names over the years. Common names often vary from place to place. Changes in scientific names generally reflect altered and improved understanding of genetic relationships.