Sound Water Stewards are trained volunteers working in and around Island County for a healthy, sustainable marine environment through education, science and stewardship.
Steward Stacey Thompson, SWS Class of 2011, wrote a series of articles about exploring the low tide beaches of Camano and Whidbey Islands, alone, in the fresh air, during the long days of Covid restrictions, January through May. Her exploration prompts all of us to get out onto a beach and see what we can find!
January 2021 – A Winter Beach Walk
February 2021 – Zones 2 and 3: Midlittoral Zones: The Beachcombing Zone
April 2021 – Rocky Beach Intertidal Zone 4
May 2021 – Minus Tide at Keystone Jetty & at Bush Point
What can you see on the beach in the Winter? Why go out in the cold?
When you go for a beach walk on a cold winter’s day you will be sure to notice the birds at the shore. While gulls, eagles and raptors are residents, many birds are migratory species just visiting for the winter. Tundra and trumpeter swans, snow geese and Canadian geese may be flying by, honking loudly, as well as numerous species of ducks such as the smallest of all, the bufflehead. This little black and white duck looks like a plush toy afloat, and usually shows up in small flocks. It dives for mollusks and crustaceans. Other ducks dive for fish, too.
Beachcombing has been a way of life for me. I love to look for agates, wishing rocks, shells, and driftwood. When I read in 2010 that there was a volunteer organization that monitored beaches as one of the citizen science projects, I signed up for the 2011 Training to become an official beach monitor volunteer.
Beach monitoring is a citizen science activity where we explore our shores systematically with our fellow Stewards, inventorying the beach and its resident organisms that are lying on or scurrying about the seaweed, lichen, sand, and rocks. After diligent inventorying, we usually eat lunch together at the hosts’ beach house and visit with each other, one of my favorite parts of Sound Water Stewards. There are many interesting people to meet in this amazing organization.
This month I am looking at rocky beaches which reveal four of the “usual suspects” regularly found in Zone One (splash zone, the upper zone or high tide zone) within the intertidal zonations. These are the red velvet mite, periwinkles, limpets, and small brown barnacles.
Zone One can be found 9 feet above the 0.0 tide level. The organisms in this high tide zone must be adapted to the heat, sunlight, freshwater from runoff and rain, as well as to the competition and predators in that zone.
Small brown barnacles, Chthamalus dalli, measure about 5-6 mm at their base. Like their cousins the larger white Balanus glandula, measuring about 1.5 cm, they comb the water for microscopic food. They are filter feeders and must be submerged in water to feed. The small brown barnacle has four plates that, when closed form a cross-shape. Some of these small barnacles are dry for longer periods than others but can live through this zone’s extreme conditions. Check to see if the barnacles are alive by seeing if the plates are closed together at the top.
Another Zone One creature we find regularly is the bright red velvet mite, Neomolgus littoralis. This little mite can be easily spotted because of its bright color. It is fun to spot on your winter walk in the splash zone, high tide. It uses its eight legs to go after small flies then sucks their fluids. Mites do what they do.
Continuing your winter walk you will probably run across numerous periwinkles, tiny marine snails with small dark shells, Littorina sitkana, 1.5 cm tall. They have a strong spiral shape. A closely related species is checkered black and white called the checkered periwinkle, Littorina scutulata, which is barely 1 cm in height.
You will more than likely spot Lottia digitalis, the limpet, when you see periwinkles. Its shell is distinctly ribbed with an apex placed anteriorly and reaches 2 cm. Snails and limpets are herbivores that scrape algae from the rocks. They congregate along the crevices where moisture collects and where algae grow. Look under lower edges of boulders for limpets and periwinkle.
These are just a few of the creatures. What else can you find in the splash zone? Are you noticing rockweed, lichen and other species?
Enjoy your time on the beach. How fortunate we are to live on the beautiful Salish Seashores and can get out away from our quarantined lives. Hope to see you this Spring and Summer during monitoring. And remember, return creatures and rocks to where you found them.
Beach monitoring is SWS citizen science activity that comes naturally to me. So when I go out for a walk on a beach to see what I can find, observe and discover about seashore life, I usually end up in Zones Two or Three of the intertidal zones on a rocky beach habitat. This is a turbulent zone, exposed twice within a 24 hour period. It extends from the upper limit of the white barnacles, Balanus glandula, to the lower limits of the brown algae, depending on the tides.
Life is more abundant in lower zones and less diverse towards high intertidal Zone One. Zones Two and Three have more time underwater with less temperature changes but can still be pounded by waves. Many plants and animals attach themselves and are either very sturdy or very flexible, such as mussels or rockweed. Sunlight can be transmitted to shallower, submerged plants for photosynthesis. Mussels, snails, limpets, crabs, barnacles, sea stars, sponges, chitons, seaweeds and other algae abound.
There are many challenges to organisms in this midlittoral zone. They are exposed to air, sunlight, and temperature changes. But these hurdles are met with unique adaptations to counter dehydration. Mobile animals can move to a more suitable region or find shelter to avoid drying out. Attached organisms manage water loss in many ways. Some can produce egg cases that resist desiccation, some reduce metabolic rates and others respond by reducing water permeability. In response to predation, some have calcifications making them harder to eat. Bioluminescence blinds, scares or misleads predators. Camouflage can protect some. Another challenge is wave action. Organisms burrow into the sediment or attach themselves to rocks or wood to brace themselves for survival.
Now let’s see what we find on our walk. The rockweed is obvious and common. This brown alga, Fucus distichus, is flattened and branched and its branches are swollen and warty where sperm and eggs are produced. It is attached with a button-like holdfast and thrives in spring and summer. Many algae, including the Hildenbrandia, an encrusting red alga, like tidepools and wet crevices.
Snails produce those shells we like to find on a walk. Nucella is a marine gastropod mollusk with a strong shell that has a well-developed spire. All species of Nucella are carnivorous predators, attacking Balanus glandula barnacles and mussels. They drill a hole in the barnacle, secrete a toxic substance and consume their favorite meal. There are many different species in this genus that have same or similar characteristics such as different numbers of whorls or slight variations. Clusters of eggs are attached to the bottom of rocks in “flask-shaped capsules” with 15-55 eggs in each capsule and sometimes referred to as “Sea oats.” They are plentiful in spring and summer.
Turn over a rock or two and what will you find? Most definitely, crabs scampering away. Two shore crabs, Hemigrapsus nudus and H. oregonensis crabs are often found together. Both have almost rectangular carapaces. H. nudus is usually reddish and its legs are not hairy. The H. oregonensis. is usually grayish-green and its legs have noticeable hairs. Both can really pinch if they feel threatened, but they eat seaweed, Ulva. I also can find Nucella eggs attached to the bottom of the rock.
What can you find on a rocky beach on Puget Sound that will pique your curiosity?
Remember your beach etiquette. Return all rocks and sand that was moved to their original place. Walk softly and have a great time in the fresh air on the beach.
- Learn more about zonation and zones at https://soundwaterstewards.org/icbw/essays/zonation.htm
- Learn more about the life forms at https://ad79bc48-4fb6-4b94-b853-15a2d6eeb42d.filesusr.com/ugd/739787_2d85be17658947e2985b267b2632d2ab.pdf