Nature Notes from Argyll
(and occasionally other places)
Sun 9 Mar 2008 Taynuilt
Last time I mentioned that the only brown seaweed found on the Inverawe shore of Loch Etive was Spiral Wrack. The Taynuilt shore is close to the Inverawe shore but separated from it by the mouth of the River Awe. It has the full complement of wracks, though some in small numbers. On beaches like this the seaweeds are attached to fairly small stones which can be moved about by the tides despite the sheltered sea-loch conditions. This was proved by the existence of a few stones with kelp plants on, well above the level at which kelp grows. I didn't count these for the survey as I felt that if they can move up the beach they can also move along it and may have originated elsewhere. The wracks seemed mostly within their expected zones so I took them as genuine.
Spiral Wrack was pretty sparse on this shore, giving way almost immediately to Bladder Wrack, shown attached to a stone above left. This species continued down the shore for some distance, but its usual companion, Egg Wrack, above right, was very scarce on the open beach, though there is a lot of it in the shelter of the old pier. It lacked the red tufts of Polysiphonia lanosa which almost invariably grow on it by the ocean.
Saw Wrack, with its toothed edges, forms the zone below Bladder Wrack on a normal beach. Here, it was very occasional, and did not have the Spirorbis tubes which normally decorate its fronds. Channelled Wrack, on the right, was in its usual place at the top of the shore. You can see from all these pictures that the seaweed cover is sparse with plenty of bare beach visible in between. All these seaweeds are on movable stones. Channelled Wrack also forms a zone on the stonework of the old pier.
Above Channelled Wrack on the west stonework of the old pier is the Sea Plantain zone, the fresh Spring growth brightening up the dingy browns and blacks of its surroundings. Neither Channelled Wrack nor Sea Plantain occur on the east wall. Perhaps the water is more saline on the west side due to the pier forcing the Awe waters away from the edge? Bladder Wrack and Egg Wrack occur on both walls.
Thu 13 Mar 2008 Taynuilt
Brachythecium rutabulum (above right) is a common moss recognisable by the silvery shoot tips and, at this time of year, by the golden or brownish-green shoots mixed among the bright green ones, looking as if two kinds of moss are growing together.
Fri 14 Mar 2008 Ganavan to Dunstaffnage
This is a beautiful walk not far from Oban. Here is a view of Mull from the top of the cliffs. The sea is in shadow apart from a distant strip along the Mull coast.
The overland route is across open moorland with a ribbon of gorse and birch scrub along the clifftop. This contained at least two male Chaffinches proclaiming their territories in song, though it was more like Whinchat than Chaffinch country. The clouds soon cleared. Ravens cronked overhead. The walk can be varied by doing parts of the return trip beneath the cliffs. There are several places where it's easy to get up and down.
Ptychomitrium polyphyllum forms cushions on bare rock near the tideline. The capsule on the left still has its calyptra, while that on the right has shed the calyptra and shows the peristome teeth. The second pic is Polytrichum juniperinum, a very low-growing moss similar to P piliferum, which we've had before, but with brown instead of white hair-points to the leaves. Here it's with a Hypnum species on rock.
This part of the coast faces the open sea, although it's not a totally exposed shore as it's sheltered by Mull. At any rate it seems a good base point for the Loch Etive survey, as the water is fully saline here without doubt.
Here the complete zonation of brown wracks is found. I mentioned above that at Taynuilt on Loch Etive, Saw Wrack and Egg Wrack are free of their usual adornment with Spirorbis and Polysiphonia respectively. Here at Dunstaffnage the Saw Wrack does have the curled white tubes of the bristle-worm Spirorbis spirorbis, above left. But surprisingly there is still no Polysiphonia on the Egg Wrack.
The stringy bluish-green seaweed in the RH pic is Cladophora rupestris. It's frequent here on rock from the mid Bladder Wrack zone to well down the Saw Wrack zone, and perhaps further (must time these visits for spring tides!)
Here's another green seaweed, Ulva intestinalis, on the upper shore at the boundary between the Channelled and Spiral Wrack zones, where a trickle of fresh water runs down. As the close-up shows, it is like a mass of deflated green cellophane tubes. No doubt it's a lot prettier under water.
Like seaweeds, winkles have their zones on the shore. The Flat Periwinkle, left, lives on the lower middle shore and is fond of Bladder Wrack. The Edible Periwinkle, centre, occurs from the middle shore down to below the low-tide mark, and is particularly fond of kelp, including washed-up loose bits. Rough Periwinkles, right, shelter in rock crevices on the upper shore when the tide is out. Another kind called the Small Periwinkle occurs even higher, often in the splash zone, but I didn't find them here though they may well be along this coast in places.
The barnacle Semibalanus balanoides is the common kind on these shores. It can be recognised by the lowest (i.e. further from the cross-mark) outer plate being the largest and by the horizontally symmetrical diamond-shaped opening. The two large and two tiny Beadlet Anemones were in a shallow rock pool.
On much of this coast the rock is conglomerate, i.e. it consists of smallish stones set in a matrix of some other rock. Both the matrix and the contained stones vary, particularly the latter. The effect is especially striking when the matrix is white calcite, as here. There are also veins of calcite without any stones in, as shown in the RH pic where it has a pinkish tinge in places. The conglomerate was formed in the lower Devonian era, about 400 million years ago.
The drake Eider has a pinkish wash on his breast signifying breeding condition. There was a lot of cooing at this lively get-together and I think I can see a bit of billing too...
Back at Ganavan a lone Eider had hauled out on a spit of rock in the failing light. The picture is very misleading as the Mull ferry, and Mull itself, were far away in the distance!
All photos and other content copyright © Carl Farmer