Oceanic Gyres and Garbage Patches

Written June 27, 2012, published August 2012

The 2011 tsunami inadvertently provided ocean biologists with study material for pelagic drift for years to come. The word pelagic is from the Greek word for open sea, pélagos. Probably the best-known pelagic ecosystem in the world is the Sargasso Sea, in the Atlantic Ocean. This is a natural gyre, or eddy, where floating seaweed is common. It is a large oval around 700 statute miles wide and 2,000 statute miles long, and is near Bermuda on the west edge. The Sargasso Sea is bordered on all sides by currents. 

This sea is named for floating brown seaweed, in the genus Sargassum, which is common throughout the eddy area. While most Sargassum species are benthic and live associated with seabeds, Sargassums in the Sargasso Sea are holopelagic (free-floating throughout their lives). 

A local seaweed in this genus, Sargassum muticum, lives on shells, cobbles and wood on tidelands of Willapa Bay. Like other Sargassums, it has dense leafy brown fronds with numerous small air bladders, which help it to float up off the bottom and probably gives it more access to light. It is one of dozens of species that arrived with Pacific oyster spat in the early to mid 20^th Century from Japan, and now lives in many estuaries around the world. 

A recent expedition to the Sargassum Sea confirmed that numerous endemic species, which live nowhere else on earth, are found among this floating seaweed forest.  This floating reef structure is used by many species; likewise, the cover provided by Sargassum is attractive to many fish species in the otherwise open ocean.

Being a gyre, the Sargasso Sea is a watery trap for debris. This golden brown seaweed community is slowly being filled with plastics from the surrounding currents and shores of the Atlantic Ocean. The Sargasso Sea is becoming the Great Atlantic Garbage Patch. 

In the Pacific, there is no Sargasso Sea West, but there is a marine debris and plastics gyre in a similar location, in the North Pacific Gyre. It is called the Great Pacific Garbage Patch. The densest part of this gyre is between 135°W to 155°W and 35°N to 42°N, a long oval area that is 480 by 1400 statute miles wide. The exact size is difficult to measure, because the plastics in it gather in a floating belt in the water, not a raft lifted up out of the water. It is north of the Hawaiian archipelago, and stretches east and west for hundreds of miles. There are also several other gyres in the world’s oceans, in the south Pacific, Indian and south Atlantic Oceans. All of these are places where plastics accumulate. 

Locally, we know there is a plastics debris problem on our beaches, but compared to some Hawaiian beaches, our beaches approach pristine condition. Some beaches on the north side of the Hawaiian Islands accumulate huge amounts of plastic each year in drifts 5 to 8 feet thick, more than 20 feet wide, and miles long. 

When the energetics of plastic recycling are worked out, these floating garbage patches and plastics-rich beaches may become resource extraction areas, where harvesters gather plastics to make diesel fuel. The process is simple; it’s the energy to heat the plastics that makes this expensive as a process right now. 

Tsunami Debris and Pelagic Species

Written June 27, 2012, published July 2014

As massive amounts of floating debris begins to wash ashore from the tragic earthquake and tsunami in Japan, March, 2011, the possibility that species local to Japanese waters could be transported to our coast in debris went abruptly from speculation to reality when a floating dock and boats arrived on beaches from BC to Oregon. With it is an opportunity to track estuarine and pelagic drift species, to determine biologically how long a floating object has been in the water.

Growing on the dock were dozens of species native to Japan, including a few that might be considered invasive. Species found and removed from the dock’s surfaces included: brown, green and red seaweeds; gooseneck and encrusting barnacles; snails; crabs; clams; several worms; bryozoans; and starfish.  Likewise the small boat that washed up on our beach was well colonized with a number species. These were in Japanese waters before the earthquake. 

A brown plastic beverage bottle and a small float both were colonized by pelagic gooseneck barnacles, Lepis anatifer, a widespread oceanic barnacle. Photo by Kathleen Sayce

Land-based floating debris carries a different set of organisms; these are typically from oceanic waters. Open water species are called pelagic, from the Greek word for open sea. A very common animal on marine debris that arrives on our beach is Lepis anatifera, the Pelagic Gooseneck Barnacle. These barnacles are often seen in the company of bryozoans and filamentous diatoms on floating objects; these species are widespread, and are found on drifting objects all over the world. 

Gooseneck barnacles are so named because they have long pedicles, or necks, which attach to subtidal rocks, and to driftwood, floats, water bottles, docks, boat hulls and soccer balls. All barnacles are hermaphrodites with internal fertilization. Eggs are held inside the shell of the adult barnacle until the larvae hatch. As drift moves across the ocean, barnacle larvae swim with it, and like many marine invertebrates, the young animals settle near or on adults of the same species. Thus multiple generations of pelagic gooseneck barnacles live on drift that has been in the water for a year or more, and only one generation of barnacles lives on drift that recently entered marine waters. 

On a recent cleanup ride with Russ Lewis, a beachcomber and volunteer with Grassroots Garbage Gang, we picked up plastic debris from Oysterville Road into Leadbetter State Park. In three hours we gathered bags of debris from the 2011 tsunami:  Numerous foam pieces, white, orange-yellow and light blue to light green, some with black roofing on it; several water bottles with Japanese logos; and fishing floats, small to large. 

This closeup of a clump of gooseneck barnacles shows that several generations of barnacles have lived on this float, indicating that it has been in the water for many months. Photo by Kathleen Sayce

One fishing float had oysters more than two inches long, encrusting barnacles, filamentous diatoms and gooseneck barnacles; this float was probably in the water before the tsunami.  The largest gooseneck barnacles we found were more than four inches long, with shells one and a half inches long. Attached to these adults were tiny gooseneck barnacles less than one half inch long. 

We did not see the numerous coastal species associated with the floating dock. Most of the debris we found was probably colonized by pelagic species after it was dragged offshore.  

Normally the biggest beach cleanup of the year is the 5^th of July cleanup, when more than fifteen tons of fireworks and party debris is removed. This year and for several years to come, no one knows how much extra debris will be removed from local beaches due to the 2011 tsunami. We treasure our local beaches. If you do too, join the cleanup team on the 5^th, or better yet, pick out your own mile, half mile, or quarter mile section and keep it clean year round, as dozens of Grassroots Garbage Gang volunteers already do. 

After the Cretaceous: The Lincoln Creek Formation

Written May 7, 2012, published June 2014

Following the end-Cretaceous asteroid impact and subsequent dying off of dinosaurs and many large reptiles, 65.5 ma (million years ago), this area was a large shallow warm sea, dotted with volcanic islands, and filled with coral and oyster reefs. Along the east side of the sea, swamps grew on low slopes near the water, near present-day Centralia and Chehalis, WA. Plants grew in these swamps that later formed layers of coal.  In fossil-speak these are called coal swamps. This sea persisted for 50 my (million years), to around 20 ma, in the early Miocene. 

Many marine fossils are found in rocks from this period, including: snails, clams, corals, crinoids, brachiopods, barnacles, sharks’ teeth, fish, whales, seals and turtles. Burrowing shrimp from 45 ma were found in marine sediments; similar shrimp species live in Willapa Bay today.  

These geologic periods had wet warm climates and considerable volcanic activity due to a nearby subduction zone. Water-washed ash mixed with marine silts and sands makes a very good fossil-preserving combination. 

Three concretions and a fossil crab (inside a fourth concretion), were loaned by Karla Nelson for this article. She found these several decades ago while camping on Lincoln Creek in the east Willapa Hills with her family. Photo by Kathleen Sayce

A distinctive round rock called a ‘concretion’ often forms in marine sediments, where as fossilization proceeds, sediments cement together to make round rocks, with the fossil at the center. Concretions form easily with small shells and crustaceans, such as shrimp, barnacles and crabs. 

An outstanding sedimentary rock formation, the Lincoln Creek Formation, is from this period. The Lincoln Creek Formation is 2,000 to 9,000 feet thick, composed of tuffaceous (ashy) siltstone to fine-grained sandstone, and formed 37 ma.  It was originally described from a site on Lincoln Creek, off the Chehalis River in the Grays River Basin, Lewis County, WA, and covers about 1500 square miles in southwest Washington, including areas of Pacific and Wahkiakum Counties. This formation has a good exposure along the Willapa River east of Raymond.  

Mollusks and crustaceans are common in the Lincoln Creek Formation, as are microscopic foraminifera. Crabs are particularly common. Karla Nelson, Time Enough Books, and her family often camped on Lincoln Creek when she was a child, and collected concretions. When opened, these concretions typically contain fossilized crabs. 

Swampy shorelines persisted in lowlands along the west side of the Cascades during the Paleocene to early Miocene Period.  Trees in these swamps included palms and many conifers, mallows, species in the rose family (hawthorn, spiraea, amelanchier, sorbus, prunus, rubus), also gingko, banana, magnolia, and grasses. Specimens of many plant and animal fossils from this period can be seen at the Burke Museum ( HYPERLINK "http://www.burkemuseum.org/" www.burkemuseum.org/ ), Seattle, WA. 

The most similar modern analog to those ancient coal swamps is mangrove thickets in the tropics. For an analog of that ancient tropical shallow sea, the most similar area today is Indonesia, including earthquakes, tsunamis and active volcanoes. 

Lost Landscapes: Coastal prairies before beach grass 

Written May 31, 2012, published June 2012

One of these days I’m going to write a book about all the lost views and vanished landscapes in this area. Until that day comes, here’s a start on the changes:  Simply put, the plants that live on the dunes today are different from those of the past. This change in species also changed the appearance of the dunes.

Barbara Minard, Columbia-Pacific Heritage Museum, proffered this image of the Breakers Hotel in north Long Beach; the date is between December 1900 and 1904. This is a winter or early spring photograph, showing abundant driftwood on the beach, and on the dune, very low vegetation. There’s bare sand in the foreground, and some of it may be black sand. 

Image loaned from Columbia-Pacific Heritage Museum, of the Breakers Hotel, looking north. Note the extensive driftwood on the west (left side of the image), the fence near the middle left, and the treeline, well to the east of the beach and fore dune. 

The Breakers Hotel stood on the dune that formed after the last subduction zone earthquake, which was in 1700. When this photo was taken the dune was 200 years old.  Today, a row of houses stands in this spot, more than one thousand feet east of the present beach. Note that the vegetation is very low and like a patchy turf. American dunegrass is native here, and was growing in the dunes in 1900. It goes dormant in fall and dies back to the ground. Many other dune plants are also perennial and also die back to the ground in winter, so the ground would look partially bare in winter. 

In spring, an image taken at this same location would show wildflowers, including beach lupine, footsteps-of-spring, sea thrift, early blue violet, harsh paintbrush, western buttercup, checkered lily and gray beachpea. By midsummer, dune goldenrod and white brodiaea would be flowering. There may have been patches of tough-leaf iris and nodding onion. Two orchids, hooded maiden’s-tresses and coast piperia, flower in mid to late summer. Beach morning glory, yellow and pink sandverbena and beach carrot thrive in open sandy dunes.  Several other native grasses grew in small tufts and clumps. 

Today, many of these species have all but vanished from the dunes due to the arrival of introduced beachgrasses.  Pink sandverbena is so rare today that when it appeared at Leadbetter Point a few years ago, it had not been seen in Washington for more than 60 years.  Snowy Plovers, Streaked Horned Larks and Oregon Silverspot butterflies were among the animal species that thrived in these open sandy, wildflower-rich coastal prairies. 

Not all dune species have suffered. Still flowering on today’s dunes are beach strawberry, purple beachpea, and patches of yarrow, pearly everlasting and silver bursage.  Sandbur is doing very well, having made a transition from dunes to lawns, to the dismay of bare feet.  Kinnikinnick grows among shore pines, and is a good groundcover for home gardens, in both full sun and partial shade.  As for animals, native voles, shrews, and thatch ants thrive in the beachgrass dominated dunes. 

There are small fragments of coastal prairie scattered along the peninsula; they are no longer on the outer dune line, but well inland, usually more than one thousand feet from the present beach. The diversity of wildflowers in these small remnant patches is amazing.

The vanished landscape that this image hints at is a diverse coastal prairie, rich in colorful flowers, which thrived on summer drought, fire, salt, winter rain and strong winds. In comparison, today’s dunes are very nearly monocultures, dominated by two species of beachgrass.  Someone probably has summer pictures of the dunes from a century or more ago, showing those now-vanished wildflowers. I’d love to see the images of the wildflower prairie that used to flower along the ocean beach.  As for the introduced beachgrasses, these species make gorgeous green grasslands in the dunes, but these grasslands are completely different from the colorful dunes of past millennia. 

Photo courtesy Columbia-Pacific Heritage Museum

Bud-break, Leaf-out and Leaf Colors

Written March 6, 2012, published in late March, 2012

By March, there are several signs that the new growing season is reaching the Pacific Northwest coast. Salmonberries break bud, and are in flower in sheltered areas. Skunk cabbage opens its distinctive large yellow flowers. Willows flower, first the hairy outer bracts––the pussy willows, then yellow anthers, followed by white stigmas. The first Rufus Hummingbirds arrive, more aggressive and much louder than the Anna’s Hummingbirds that over-winter here. With typical night temperatures above 40 °F, male Pacific Chorus Frogs, AKA Tree Frogs, call for babes. Brant flock on Willapa Bay in larger and larger groups, restless, leaping into the air as a flock more often, settling back down to feed more slowly. The first swallows and Turkey Vultures arrive, usually in mid-March. 

Leaf-out gets underway slowly. Alders and willows flower in February and March, and after flowering, open their leaves for the season. Red alders open leaves that are light green, then darken. Willow leaves vary from silvery green to gold-green. Big-leaf maples open both leaves and flowers at the same time, with a lovely yellow-gold color. Some years, the Willapa Hills have a golden wash as the maples start leaf-out. It’s startling against a backdrop of dark green conifer foliage. Cottonwoods have a nice gold color too. Last to arrive are Garry oak and Oregon ash, both waiting well into late April or May to start; both these ‘late leafers’ have a pale gold color. 

Why are these colors important? Tree leaves are green, yes, but they don’t open up with their photosynthetic mechanisms completely in place and operational. Leaves are designed to capture light, photon by photon, and turn it into food. Simple sugars made in the leaf from basic materials––sunlight, water, carbon dioxide––become more leaves, new roots, and cellulose, the natural biopolymer that makes wood. 

As leaves unfold, the photosynthetic powerhouse inside the cells also has to assemble, and this is where light-green, gray-green, gold-green, yellow-gold, and in some cases, red, purple and near black leaf colors, come from: non-green pigments that protect the new leaf tissue from photo-destruction. Sunlight drives life, and it also can destroy plant tissues before the new chloroplasts have completely assembled.  These colors are protective pigments that keep fragile new cells alive in the presence of sunlight until their chloroplasts are green and using those photons to make sugars.

These pigments are most noticeable in spring before the chloroplasts have completely assembled. Once chloroplasts are completely operational, those leaves look green to us. The protective pigments are still there, we’ll see them again in the fall as the leaves shut down and are shed. The intense green of fully functioning leaves will hide the other colors during the summer. 

Nurseries promote plants with non-green foliage: yellow, red, purple, black. These plants were grown from abnormal plants, or in some cases, twigs on otherwise normal shrubs and trees. We like to have pleasing colors around us, including foliage that is other than simply green. And so nurseries offer conifers, hardwoods, shrubs, grasses and perennials with a range of foliage colors, all selected from naturally variable plants. The mechanism by which these colors are produced in the plants varies. Some plants produce less chlorophyll than normal, others produce higher amounts of other pigments. 

One of the most striking of the former was Kiidk'yaas (the Ancient One) also known as the Golden Spruce, a tree that lived in a forest on Haida Gwaii archipelago in northern British Columbia. This spruce had golden needles and stood like a golden spire in the forest. It lived for almost three hundred years, until a day in 1997 when it was cut down by an unemployed forest engineer making a confused political statement. His fate is unknown; he was arrested and disappeared on his way to trial. Meanwhile, cuttings of the golden spruce were grafted onto a normal green Sitka spruce by University of British Columbia researchers in the 1970s. Its progeny live today as Picea sitchensis ‘Aurea,” or “Bentham’s Sunlight.” The golden spruce lacks about eighty percent of its normal chlorophyll, and needs to grow in the shade of other trees to protect it when young. 

A very striking color change takes place in cranberries between summer and winter. Cranberries use red pigments to protect their leaves and shoots during winter, turning dark red in fall. Come spring, as plants come out of dormancy and start growing, leaf color goes back to green, though red protective colors never completely go away. 

These seasonal changes are not as striking as the fall colors and spring leaf-out of the great hardwood forests of the East Coast. In spring they herald another seasonal change: the arrival of the lawn-growing season. I’m getting my mower cleaned and its blade sharpened for another summer of tussle with my lawn. 

Where's Our Gold?  Black sand beaches and gold

Written February 23, 2012, published in March 2014

Those who visit the beaches from Leadbetter Point to Cape Disappointment probably know that southern beaches are darkest colored in winter. Benson Beach is the darkest of all, often with no light-colored sand, particularly at the north end. Black sand beaches around the world often have gold deposits, and if so, where’s the gold on this beach?

Beard's Hollow, north of North Head, is a good place to see black sands any time of year,. In this photo, the dark sands are interspersed with lighter quartz and feldspar sands in the foreground. Photo by Kathleen Sayce

Black sand beaches are typically made from basalt, either from fresh lava, ground by the ocean into fine bits, which are common on Hawaiian beaches, or eroded out of hard rock by water and carried downstream in rivers. Black sands are of particular interest to miners because they often contain important minerals and elements, including iron, gold, platinum and titanium, and as such are called placers. 

Gold has been noted in black sands along the Columbia River from northeast Washington all the way downriver to the coast, and on the ocean beaches. Several river beaches became placer mines. The first mention of gold in black sands at Cape Disappointment was in a Coast Survey report to Congress in 1858.  The amounts seen were not sufficient to support gold mining, the report noted. Profitable mining is based on finding high concentrations of gold and separating it in a cost-effective manner from the surrounding non-gold materials. 

Sands sort with wind and water. In this close up, approximately 2 feet across, you can see black bars of heavy black sands, brownish feldspars in the upper left, and lighter quartz sands throughout the image. Photo by Kathleen Sayce

Water sorts minerals out by weight to make placer deposits; in geo-speak this is called gravity separation. You can often see gravity separation on the beach as the tide recedes in the summer. Mineral grains of different weight sort out with every wave, into black, brown, greenish, reflective light brown and whitish layers. Gold is about six times as heavy as quartz, the lightest element; it settles out first. The magnetic black layers are the heaviest, twice as heavy as quartz, and drop out next; they have heavy elements, including iron, manganese and titanium. The whitish and brown layers are lighter and drop out last as the water recedes; they contain lightweight silica minerals like quartz and feldspar, which are the most common minerals in our beach sands. There’s also some mica, very light, which makes the beach glitter.

Valuable placer minerals erode out of hard rocks, including basalt, granite and metamorphic rocks. Sands on the ocean beaches in Washington and Oregon were analyzed for their component minerals, in part to help determine where the beach sands come from, and also to help determine if there might be economically valuable deposits of minerals. From a book by Paul Komar, The Pacific Northwest Coast, 1998, comes a description of beach sand grains around the Columbia entrance: clear quartz, green and brown feldspar, light brown biotite, dark hypersthene (which includes black magnetite and ilmenite), dark green augite, light brown enstatite, white zircon and clear to light pink garnet. Magnetite and ilmenite minerals can contain gold or titanium along with iron, manganese and magnesium. 

Placers accumulate in locations where the heaviest sands drop out easily. These include river edges at or below low water, river mouths and deltas, coast beaches, and offshore. Where placers form on beaches, surf picks up sand grains on the benthic surface and deposits them high in the surf zone. The black sands are generally too heavy to blow around in the wind. Water does move them, though it has to be moving fast to keep sand in suspension. Storms, floods and tsunamis move around massive amounts of sand. 

On Benson Beach, Cape Disappointment State Park, in winter the quartz sands move offshore, and the black heavy sands stay behind. To the left, the beach is largely composed of black sand. In the middle, lighter quartz and feldspar sands have blown into the dune. Photo by Kathleen Sayce.

Tsunamis come immediately after local subduction zone earthquakes, and flood uplands with ocean sands. The erosions that follows pulls light sands off local beaches and leaves behind heavier minerals in a large-scale gravity-separation process. In geologic time, local earthquakes generated in the Cascadia subduction zone have been followed by hundreds of feet of beach erosion before the shoreline stabilizes and a new outer dune rebuilds. This has been well documented by students of Curt Peterson, Portland State University, and others. 

In the months following earthquakes the surf carries sands back onshore to form a new dune. Placers are buried at the bottom of this new dune. More geo-speak: placers are called lags or lag deposits when they are placed at the base of dunes. As with the sorting at wave edges, lighter sands move more easily in wind and water, and are re-sorted and placed higher. Black sands end up being concentrated at the dune base.  The tsunami-derived placers under our old dunes are several feet thick. These iron-rich placers often give a distinctive orange tinge and iron taste to water from shallow wells pumping water from this layer. Some gold is at the bottom of dunes in lag deposits. 

Sea level also determines where gold goes. During the past 1.9 million years of the Pleistocene Epoch, sea level was as much as 350 ft lower than today. The Columbia River and other local rivers carried sediments past the local area and out to the edge of the continental shelf in river channels.  This Pleistocene gold is largely in the deep ocean today, or well buried in those river channels at historic low sea levels levels, and covered by younger sediments. 

When the great floods from the Glacial Lakes in the Rockies occurred, sea level was still so low, 300 to 200 feet below today’s level, that those floods roared past in the Columbia River Valley, and out the Astoria Canyon. This ‘glacial floods’ gold is also in the deep ocean and at the lower end of the continental shelf in the Astoria canyon and alluvial fan. 

Today, ocean currents spread sands from the Columbia northwest across the continental shelf. Surf carries some sands east to the beaches, constantly reworking and sorting the fine to heavy grains. Only the heaviest surf can move the heaviest sands, so most of the heavy grains stay behind in deeper waters. This gold is on the continental shelf, spread northwest of the Columbia River. If there are deposits worthy of mining, this is likely where they will be, in the ocean northwest of the entrance. Mining is possible, once concentrated deposits are located, but extraction damages fish and crab habitat. When damaged, it takes years to recover natural productivity on the benthic surface.  

River water slows as it reaches the ocean, dropping most of its sand at the Columbia River Entrance. Historically, Benson Beach was on the main channel, and received considerable black sand from the river as it wrapped around Cape Disappointment. This beach and buried sands at depth around Baker’s Bay probably have more gold than any other beach in this area, but still not enough to justify mining. There are too many non-valuable minerals mixed in with it. 

One of Paul Komar’s graduate students sampled sands along the beaches from Seaside to Leadbetter, and noted another black sand concentration at Leadbetter Point. He proposed that currents from Willapa Bay helped stop longshore movement of sand, and re-concentrated black sands in the Willapa Entrance. Lighter sands made it across and went on north; heavy sands stayed at the Point. 

With the main channel pushed south early in the twentieth century, most black sands from the Columbia River today are deposited around that channel and Clatsop spit. New black sand deposits are forming today on the south side of the river. Channel dredging shifts a little modern river gold offshore with every load, creating small placers in the dredge disposal areas. 

This is where our gold is: scattered all over, under dunes, at the Columbia and Willapa Entrances, in the ocean, in deeply buried sands along rivers and in channels. Unfortunately, it’s not up on the beach where it’s easy to find and remove.