Star Island Intertidal Seaweeds

Carragheen Moss

False Irish moss is a red seaweed, resembling a stiff, thinner version of Irish moss. The fronds have thick rims and seem to have a channel flowing through them. This seaweed is found in the lower to mid tidal zone which is not exposed for too long, often attached to rocks. Sometimes, you find this seaweed higher up on the dike or on rocks, but then growing under knotted wrack plants. Like ...more ↓

Dulse

Palmaria palmata (Linnaeus) Kuntze, also called dulse, dillisk or dilsk (from Irish/Scottish Gaelic duileasc/duileasg), red dulse, sea lettuce flakes or creathnach, is a red alga (

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Palmaria palmata (Linnaeus) Kuntze, also called dulse, dillisk or dilsk (from Irish/Scottish Gaelic duileasc/duileasg), red dulse, sea lettuce flakes or creathnach, is a red alga (Rhodophyta) previously referred to as Rhodymenia palmata (Linnaeus) Greville. It grows on the northern coasts of the Atlantic and Pacific oceans. It is a well-known snack food. In Iceland, where it is known as söl, it has been an important source of fiber throughout the centuries.

History[edit]

The earliest record of this species is of St Columba's monks harvesting it 1,400 years ago.^[1]

Description[edit]

Dulse grows attached by its discoid holdfast to the stipes of Laminaria or to rocks. It has a short stipe, the fronds are variable and vary in colour from deep-rose to reddish-purple and are rather leathery in texture. The flat foliose blade gradually expands and divides into broad segments ranging in size to 50 cm long and 3 cm–8 cm in width which can bear flat wedge-shaped proliferations from the edge.^[2]^[3]

The reference to Rhodymenia palmata var.mollis in Abbott and Hollenberg (1976),^[4] is now considered to refer to a different species: Palmaria mollis (Setchel et Gardner) van der Meer et Bird.^[5]^[6]

Dulse is similar to another seaweed Dilsea carnosa (Schmidel) Kuntze,^[7] Dilsea, however, is more leathery with blades up to 30 cm long and 20 cm wide. Unlike Palmaria palmata it is not branched and does not have proliferations or branches from the edge of the frond. The older blades may split, however.^[8]

Life history[edit]

The full life-history was not fully explained until 1980.^[9] Tetraspores occur in scattered sori on the mature blade, which is diploid. Spermatial sori occur scattered over most of the frond of the haploid male plant. The female gametophyte is very small stunted or encrusted, the carpogonia apparently occurring as single cells in the young plants. The male plants are blade-like and produce spermatia which fertilize the carpogonia of the female crust. After fertilization the diploid plant overgrows the female plant and develops into the tetrasporangial diploid phase attached to the female gametophyte. The adult foliose tetrasporophyte produces tetraspores meiotically.^[2] It is therefore usually the diploid tetrasporic phase or the male plant which is to be found on the shore.^[10]

Ecology[edit]

Palmaria palmata is to be found growing from mid-tide of the intertidal zone (the area between the high tide and low tide) to depths of 20 m or more in sheltered and exposed shores.^[10]

As a food[edit]

Dulse

Dulse is a good source of minerals and vitamins compared with other vegetables, contains all trace elements needed by humans, and has a high protein content.^[1]

It is commonly found from June to September and can be picked by hand when the tide is out. When picked, small snails, shell pieces and other small particles can be washed or shaken off and the plant then spread to dry. Some gatherers may turn it once and roll it into large bales to be packaged later. It is used as fodder for animals in some countries.

Dulse is commonly used in Ireland,^[11] Iceland, Atlantic Canada and the Northeast United States as food and medicine. It can be found in many health food stores or fish markets and can be ordered directly from local distributors. In Ballycastle, Northern Ireland, it is traditionally sold at the Ould Lammas Fair. It is particularly popular along the Causeway Coast. Although a fast-dying tradition,^{[citation needed]} there are many who gather their own dulse. Along the Ulster coastline from County Antrim to County Donegal, it is eaten dried and uncooked similar to how one would eat snacks at a drinks party.

It is used in cooking: Dulse's properties are similar to those of a flavour-enhancer. It is commonly referred to as dillisk on the west coast of Ireland. Dillisk is usually dried and sold as a snack food from stalls in seaside towns by periwinkle-sellers.

Fresh dulse can be eaten directly off the rocks before sun-drying. Sun-dried dulse is eaten as is or is ground to flakes or a powder. In Iceland the tradition is to eat it with butter. It can be pan fried quickly into chips, baked in the oven covered with cheese, with salsa, or simply microwaved briefly. It can be used in soups, chowders, sandwiches and salads, or added to bread/pizza dough. Finely diced, it can be used as a flavour enhancer in meat dishes, such as chili, in place of monosodium glutamate.

Dulse contains iodine, which prevents goiter.

Distribution[edit]

Palmaria palmata is the only species of Palmaria found on the coast of Atlantic Europe. It is to be found from Portugal to the Baltic coasts also on the coasts of Iceland and the Faroe Islands.^[12] It also grows on the shores of Arctic Russia, Arctic Canada, Atlantic Canada, Alaska, Japan and Korea.^[10] The records from California are of Palmaria mollis which is considered a different species.^[13]

Infections, galls, malformations and diseases[edit]

Galls, possibly produced by nematodes, copepods, and bacteria, are known to infect these plants. They were recorded as "outgrowths of tissue produced by the presence...of an animal."^[10]^[14]

References[edit]

^ ^a ^b Indergaard, M. and Minsaas, J. 1991. 2 "Animal and human nutrition." in Guiry, M.D. and Blunden, G. 1991. Seaweed Resources in Europe: Uses and Potential. John Wiley & Sons. ISBN 0-471-92947-6

^ ^a ^b Hoek, C.van den, Mann, D.G. and Jahns, H.M. 1995. Algae: An Introduction to Phycology. Cambridge University Press, Cambridge. ISBN 0-521-30419-9

^ Algaebase :: Species Detail

^ Abbott, I.A. and Hollenberg, G.J. 1976. Marine Algae of California. Stanford University Press, California. ISBN 0-8047-0867-3

^ Mondragon, J. and Mondragon, J. 2003. Seaweeds of the Pacific Coast. Sea Challengers, California. ISBN 0-930118-29-4

^ Algaebase :: Species Detail

^ Algaebase :: Species Detail

^ Hiscock, S. 1986. A Field Key to the British Red Seaweeds. Occasional Publications No. 13 . Field Studies Council, Dorset Press, Dorchester ISBN 1-85153-813-5

^ van der Meer, J.P. and Todd, E.R. 1980. The life-history of Palmaria palmata in culture. A new type for the Rhodophyta. Can. J. Bot. 58: 1250–1256

^ ^a ^b ^c ^d Irvine, L.M. & Guiry, M.D. "Palmariales and Rhodymeniales" in Irvine, L.M. 1983. Seaweeds of the British Isles. Volume 1. Part 2A. Cryptonemiales (sensu stricto) Palamriales, Rhodymeniales. British Museum (Natural History), London. ISBN 0-565-00871-4

^ Finest Quality Dulse, harvested from the shallows of the Atlantic at West Donegal

^ Børgesen, F. (1903) Marine algæ. In: Botany of the Færöes Vol. II, pp. 339-532. Copenhagen and London.

^ Algaebase :: Species Detail

^ Barton,E.S. 1891. "On the occurrence of galls in Rhodymenia palmata Grev." J.Bot. Lond. 29: 65–68

Further reading[edit]

Grubb, V.M. 1923. Preliminary note on the reproduction of Rhodymenia palmata, Ag. Ann. Bot. 37: 151–52.

Pueschel, C.M. 1979. Ultrastructure of the tetrasporogenesis in Palmaria palmata (Rhodophyta). J. Phycol. 15: 409–424.
South, G.R. and Hooper, R.G. 1980. A Catalogue and Atlas of the Benthic Marine Algae of the Island of Newfoundland. pp. 1–136. Memorial University of Newfoundland Occasional Papers in Biology.

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Irish Moss

Chondrus crispus — commonly called Irish moss or carrageen moss (Irish carraigín, "little rock") — is a species of red algae which grows abundantly along the rocky parts of the Atlantic coast of Europe and North America. In its fresh condition this protist is soft and cartilaginous, varying in color from a greenish-yellow, through red, to a dark purple or ...more ↓

Nori

Porphyra is a coldwater seaweed that grows in cold, shallow seawater. More specifically, it is a foliose red algal genus of laver, comprising approximately 70 species. It grows in the intertidal zone, typically between the upper intertidal zone and the splash zone in cold waters of temperate oceans. In East Asia, it is used to produce the sea vegetable products nori (in ...more ↓

Phycodrys rubens

A small red alga, up to 15 cm tall, with a leaf-like frond, with midrib, lateral veins and serrated margin that give the impression of an oak leaf. The disc-like holdfast gives rise to a short toughened stipe. In winter the frond wears away due to a combination of cessation of growth and wave action, leaving just the mid-rib, the blade growing back in spring. Phycodrys rubens is ...more ↓

Membranoptera alata

Membranoptera alata is a red or reddish-brown seaweed, up to 20 cm in length, with a flat, narrow frond. It exhibits a midrib and many fine, lateral veins, which can be clearly seen under a hand lens. It has many branches, arising from the central axis, which are irregular, dichotomous, and copiously branched in one plane. This perennial plant has a thin membranous ...more ↓

Rhodomela confervoides

Depth range based on 51 specimens in 1 taxon.

Environmental ranges
Depth range (m): 0 - 21.94

Graphical representation

Depth range (m): 0 - 21.94 ...more ↓

Callophyllis crispata

Type locality: Japan

rood darmwier

You don't expect seaweeds to flourish in the winter, but Dumontia contorta does. That is, it germinates in the autumn on stones and develops long thin fronds in late winter and early spring. It slowly perishes by the end of May. The only evidence you find of this seaweed in the summer is its base (the holdfast), attached to rocks. It is relatively common in tidal pools in the Wadden Sea and ...more ↓

Polyides rotundus

A dark red or blackish seaweed with smooth, cartilaginous, cylindrical fronds, branching dichotomously in roughly the same plane. The fronds rise from a fleshy, discoid holdfast up to 2 cm in diameter. The reproductive bodies occur as oval shaped swellings along the sides of the branches or occasionally encircling them. The seaweed grows up to 20 cm in length.

klein buiswier

A small reddish-brown filamentous alga most commonly associated with the fucoid alga Ascophyllum nodosum. The filaments are made up of a ring of 12 -24 elongated cells or siphons surrounding a central siphon. The plant is found wherever the host is common. Polysiphonia lanosa has occasionally been recorded as an epiphyte on Fucus serratus and Fucus vesiculosus ...more ↓

rekeklo (slekt)

Depth range based on 839 specimens in 91 taxa.
Water temperature and chemistry ranges based on 121 samples.

Environmental ranges
  Depth range (m): 0 - 66.7478
  Temperature range (°C): 11.471 - 28.104
  Nitrate (umol/L): 0.039 - 7.423
  Salinity (PPS): 34.786 - 38.201
  Oxygen (ml/l): 4.484 - 6.200
  Phosphate (umol/l): 0.052 - 1.031
  Silicate (umol/l): 1.248 ...more ↓

Coral Weed

Corallina officinalis is a calcareous red seaweed which grows in the lower and mid-littoral zones on rocky shores.

Maerl

The form of this calcareous alga is very variable. It occurs in two main forms, a thin, hard crust on hard substrata as well as an unattached, fragile, branched nodules. When young, the crustose form is smooth with some scattered young mounds but develops branches with age. The loose-lying nodules may form dense beds of algal gravel. Encrusting individuals may reach up to 20 cm across ...more ↓