Giant Green Sea Anemones from the Oregon Coast

Posted on May 10, 2013 by winderjssc

Amazingly, the Giant Green Sea Anemone (Anthopleura xanthogrammica), can grow the size of a dinner plate – up to 12 inches (30 cm) across and the same in height – though the examples shown here were only about 6 inches across. It is also known as the Rough Anemone or Solitary Anemone.

It grows on exposed rocky shores from the intertidal zone right down to depths greater than 50 feet (15 metres). It is found on the Pacific Northwest Coast from Alaska down to Panama but it is common only from Southern California northwards. These photographs were taken on the rocky shore intertidal zone at Yachats in Oregon.

Giant Green Anemones are found either growing on their own or in groups. They seem to favour living in deep and narrow cracks in the rocks where the sea rushes through with great force – these are called surge gullies. Most of the pictures in this Posting show the anemones growing tightly packed in places like this, either on the floor of or on the near vertical walls of the surge gullies – where, incidentally, I found it extremely hazardous to maintain a firm foothold while taking the photos. The nature of the location means that the creatures are alternately thrashed by incoming waves or left totally exposed while the tides are ebbing and flowing.

I also found this type of anemone in two other kinds of habitat. These were tidal rock pools (where the numbers were less numerous and the animals were totally immersed at all times) and almost completely buried in sand in areas adjacent to rock outcrops. They seem well able to withstand potential burial in softer sediments.

The beautiful green colour of the anemones, which can vary in intensity from bright blue-green emerald to more yellowy-green hues, is caused by microscopic green organisms that live symbiotically in the tentacles and disc part of the body. The column is a dull olive green and typically has many small stones and pieces of broken shell attached to it.

A. xanthogrammica supports a large population of algae. There two kinds:

Zooxanthellae, characteristically yellow brown because of the presence of pigments that partially mask the (green) chlorophyll, are dinoflagellates which have no flagella in the symbiotic phase. The other algae, called zoochlorellae, are bright green. The two types may be mixed in one specimen – even in the same tissue – or separate anemones may have only one type or the other. The algae are concentrated in the gastrodermal layer, that is, in the tissue that lines the digestive tract. Since the core of each tentacle is a branch of the digestive tract, the green color shows through the overlying tissue.

Eugene N. Kozloff 1993

This species can be eaten: the Haida people used to slowly roast it over a fire before eating. Certain chemicals can also be extracted from the anemones as a basis for medicinal heart stimulants.

More information about SEA ANEMONES on Jessica’s Nature Blog.

References

Kozloff, Eugene N. (1993) Seashore Life of the Northern Pacific Coast – An Illustrated Guide to Northern California, Oregon, Washington, and British Columbia, University of Washington Press, ISBN 0-295-96084-1.

Sept, J. Duane (2009) The Beachcomber’s Guide to Seashore Life in the Pacific Northwest, Harbour Publishing, ISBN 978-1-55017-453-3.

Oregon Sea Anemones at the OSU Hatfield Marine Science Visitor Center

Posted on May 5, 2013 by winderjssc

Whilst in Oregon a few years back I explored the seashores along the North West Pacific Coast, and found fascinating and varied forms of seashore creatures. I also visited the Oregon State University Hatfield Marine Science Center which is an excellent place to find out all about the region’s marine wildlife. It also provides a wonderful opportunity to get up close and personal to many inter-tidal creatures by providing a Touch Tank or simulated tide pool. It was fantastic to be able to photograph at close quarters many varieties of sea anemone which I had only been able to spot with difficulty in tide pools and surge gullies on the rocky shores themselves.

Here are some images of the large and colourful sea anemones (with other marine invertebrates) representative of the types that could be encountered locally in the wild.

Goose Barnacles at Yachats

Posted on April 11, 2013 by winderjssc

The Goose Barnacles on the North West Pacific Coast of America are different from the ones we see usually see in the UK. They are a sessile species, Pollicipes polymerus, and they are attached to rocks low on the shore. They are related to a similar species that grows in warmer European waters. This compares with pelagic species like, for example, Lepas anatifera, which settles on floating objects that are washed around in the sea at the mercy of tides and currents. There were huge numbers of Pollicipes on the beach at Yachats in Oregon when I visited a few years ago.

There is something rather prehistoric about the way these barnacles look. They have a tough black leathery stalk or peduncle about 2 cm long that contains the gonads and an adhesive gland for sticking them securely to the rock. They do need to hold very fast because the waves are enormous and relentless in the pounding they give the shore. The ‘head’ end, also with black flesh, contains all the other organs and the appendages that it uses to filter food particles from the water. This capitulum is protected by a series of separated white calcareous plates which are exceedingly robust and thick – often showing microscopic damage cause by an endo-lithic lichen.

The barnacles mostly live close together in large mounds or dense carpets on the rocks. They are often associated with colonies of the big California Mussel (Mytilus californianus) with the beds of which they either alternate or intermix. They occur most frequently on the lower shore, especially where the impact of the waves is greatest. They are found on vertical surfaces as well as horizontal; framing tide pools; under overhangs; and in steep-sided narrow surge gullies.

Pollicipes feeds by spreading its cirri (appendages) rather like a net so that the water passes through them. They catch small crustaceans and plankton. When sufficient particles have become trapped on the cirri, they withdraw them into the capitulum and the food is transferred to the mouth parts. The cirri do not face the oncoming waves but are arranged so that they can take advantage of the water running off the rock rather than the water hitting the rock. All of the animals in a particular group or colony will characteristically face in the same direction to maximise use of the run-off water – and this may differ from the next cluster a short distance away.

You can compare and contrast this American species of goose barnacles with ones that I have seen in the UK by clicking here for:

Goose Barnacles on Rhossili Beach

Stranded Goose Barnacles

Winkles on Worms Head Causeway

Posted on April 3, 2013 by winderjssc

The Common Winkles (Littorina littorea (Linnaeus) that live on the rocks of the Worms Head Causeway on the Gower Peninsula have a tough time! It’s an exposed and turbulent environment in which to find a home. There is certainly some shelter in deeper pools and beneath seaweeds on the outer fringing rocks of the causeway – but when the tide comes surging across the jagged strata, most winkles must be stripped from rock and weed to be tossed and battered by waves, currents, and flying debris like stones and pebbles. Winkles don’t have the same ‘sticking power’ as the limpets which can cling on and withstand the battering.

The ebbing tide leaves hundreds of thousands of winkles literally high and dry. A few of these small marine gastropods do manage by chance to remain in the more favourable conditions of temporary tide pools, even if barely covered by a few centimetres of water. Most winkles seem to stay in the open air, approximately where they have rolled by chance, lying loose and unattached in large clusters around the bases of upstanding rocks and amongst the mussel beds. Some cling on to the bare rocks, bone dry in the sun, waiting for the return of the waves.

The life style of the winkles is clearly seen in the dull surface of the rough and pitted thick shells. The shells are more comparable to those of the winkles found at nearby Whiteford Point also on Gower – and contrast markedly with the lovely pristine striped and grooved shells of winkles found among the seaweed on relatively sheltered shores like Ringstead Bay on the South Coast.

Common Winkles

Winkles living on Whiteford wood and stones

Holdfast habitat at Ringstead Bay

Stranded Goose Barnacles

Posted on April 1, 2013 by winderjssc

Just a gallery of photographs of living Common Goose Barnacles (Lepas anatifera Linnaeus) that were washed ashore in huge numbers attached to an old flotsam fishing crate. It was fascinating to watch how they opened their shells and rhythmically waved and grasped their fringed appendages, (cirripedes) in an automatic but futile gesture designed to capture food particles from the water. These pictures show various stages in the process of extending and withdrawing the cirripedes. I wrote about these seashore creatures a while ago and you can find more information about them by clicking here for Goose Barnacles on Rhossili Beach.

Worms & their Eggs on Worms Head Causeway

Posted on March 28, 2013 by winderjssc

Their were small green slime balls everywhere on the Worms Head Causeway last week. They were attached to seaweeds, rocks, and shells, either exposed to the air or in shallow tide pools. We thought at first they were the eggs of the marine polychaete paddle worm commonly called the Green Leaf Worm (Eulalia viridis (Linnaeus) – but we didn’t see any adults of that species in the locality.

We did find lots of specimens of a related species which I believe to be Phyllodoce (Anaitides) maculata (Linnaeus). These worms were slithering over mussel shells and wriggling over rocks in pools. Their appearance was most distinct. I couldn’t take any underwater close-ups but the images I captured are just about good enough to zoom in to see the characteristic appearance and patterning. I did not take any specimens to view under the microscope to confirm the identification by looking at details such as the proboscis, tentacles, and paddles. Maybe I should take specimen tubes with me and do that another time.

Unlike the bright green Eulalia viridis, the worm P. maculata is not green in colour but is described as whitish or yellowish with transverse dark brown bands. It can, however, produce green eggs as well as dark orange ones.

Reference

Hayward P. J. and Ryland J. S (1998) Handbook of the Marine Fauna of Northwest Europe, Oxford University Press, pp 215 223.

Green Sea Urchin on Worms Head Causeway

Posted on March 25, 2013 by winderjssc

The Green or Shore Sea Urchin, Psammechinus miliaris, is a common British sea urchin, and I found and photographed these live specimens from some tide pools on the Worms Head Causeway in Gower, South Wales. It seems a strange co-incidence that the colour of the spines is greenish terminating in pink – just like the tentacles of the Snakelocks Anemones which are found in the same habitat and location. I wonder whether there is any significance to this similarity?

Some Snakelocks Anemone Variations

Posted on March 24, 2013 by winderjssc

Opelet or Snakelocks Anemones – Anemonia viridis (Forskål) – exhibit quite a bit of variation in form and colour. Generally they are described as having “a smooth column, usually wider than high, up to 50 mm in diameter. Disc wide, with up to 200 long and sinuous tentacles; the tentacles rarely retracted. Column and acrorhagi (a ring of specialised warts) brownish, tentacles brown, grey or bright grass green, usually with purple tips. Contains zooxanthellae. On the shore in pools and other places open to the light, and down to about 20 m” (Hayward and Ryland 1998).

The bright green tentacle colour is caused by the tiny algae (zooxanthallae) that live within them. It is said that these organisms live in the specimens of anemone that live in well lit areas while the grey-brown anemones, without the symbiotic algae, live in areas without much light. However, that cannot be true because grey-brown and green individuals can live side by side. In the images below, Snakelocks Anemone (3) and (4), in the top left corner of the photographs you can see a plain grey-brown Snakelocks Anemone next to the featured green specimen with the pink- purple tips. And the grey-brown specimens in Snakelocks Amenone (5) – (8) were found within a few metres of the green ones.

The literature says that the tentacles of the Snakelocks Anemone are rarely retracted or withdrawn. This could be a bit of a problem for the anemone when the tide goes out. All the green anemones shown in this post were photographed in very shallow water pools in which the columns of the animals were flattened or compressed against the rock floor of the pool to ensure that the whole animal with its fully extended tentacles remained beneath the water surface. The brown specimen attached to a loose rock was fully exposed to the air and had partially retracted its tentacles – the first time I had seen this – presumably to minimise dehydration.

Typically, the Snakelocks Anemone has slender, delicate tentacles with fine gently tapering tips. The anemones from Lyme Regis in Dorset (1-4 & 8) have this characteristic. Recently, on a trip to the Worms Head Causeway, Gower, South Wales, I noticed some specimens with tentacles that were markedly stouter than usual. Additionally, a large number of the tentacles had blunt tips or had one or more constrictions towards the end. I think that the difference in tentacle shape is due to the particular conditions of the habitat. The Worms Head Causeway is a very high energy environment where the impact of wave action is accentuated; while the habitat provided by the shore at Lyme Regis tends to be a less extreme environment. The different shapes of the Worms Head Snakelocks Anemone tentacles could be the direct result of physical damage.

Reference

P. J. Hayward & J. S. Ryland (Eds) (1995 reprinted 1998), Handbook of the Marine Fauna of North-West Europe, Oxford University Press, pp 120-125.

More barnacles on rusty iron

Posted on February 27, 2013 by winderjssc

Mud Creepers

Posted on February 12, 2013 by winderjssc

Mud Creepers are a common sight on the tidal mud flats at Cairns in Queensland, Australia. Also called Telescope Shells, Mudwhelks, Telescopic Creepers, or Mangrove Mud Whelk. The Latin name is Telescopium telescopium L. They are so emblematic of the place that they have been glorified by a fantastic piece of sculpture by Dominic Johns on the Esplanade.

The reality, however, is that this large gastropod marine mollusc – living on the glutinous muds exposed by the ebbing tide – is not the most attractive of seashore creatures, in fact, a bit creepy. It is dark in colour, about 6 inches long, and the shell is very thick and heavy, The protruding muscular foot and tubular siphon of the animal are hard to distinguish from the mud itself but I believe the flesh is edible.

This sea snail seems to struggle as it drags its weighty shell across the mud in strange irregular movements without the supporting medium of water. The furrows incidentally ploughed by the shells leave networks of trails on the mud. In life the shells are often caked with mud but empty shells washed up on the beach show there is actually a great striped pattern.