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Overview

Brief Summary

Introduction

On the shore you will see the blade phase of Porphyra umbilicalis.

Identifying features
  • the blade is light to dark reddish-brown
  • the blade can be very variable in shape and form
  • it is only one cell layer thick and translucent
  • it develops from a very small disc called the holdfast
  • a common form is where the blade expands around the holdfast and appears pleated or resembles a rosette or a little cabbage
  • individuals are usually about 5–10 cm tall
Porphyra species have complex life histories. The blade that you see on the shore is just a part of the life history. There is a separate, microscopic phase that lives in shells and is called the conchocelis phase. Look for pink patches on shells because these might be evidence of conchocelis.

Conservation
Porphyra umbilicalis is a common species and does not appear to be threatened. However, because part of its life history is hidden in the shells of animals, we should not be complacent. We know very little about the tolerance of the conchocelis phase and do not know how it will respond to influences such as climate change and ocean acidification.
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Comprehensive Description

Description

 A small red alga (up to 20 cm across) with an irregularly shaped, broad frond that is membranous but tough. The plant attaches to rock via a minute discoid hold-fast, is greenish when young becoming purplish-red and has a polythene-like texture.Also known as sloke, the plant is boiled and eaten as a jelly in South Wales. Used to make laver bread a famous dish in south Wales and reportedly eaten cold with vinegar in Cornwall.
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©  The Marine Biological Association of the United Kingdom

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Distribution

Distribution and ecology

The name P. umbilicalis has been used for other species that look similar and are found in other parts of the world. However, we know from molecular studies that these are different species.

Habitat
Porphyra umbilicalis is found throughout the seashore but usually grows in the upper part of the shore where it sometimes forms a distinct zone.It is found on a wide range of hard surfaces, including bedrock, boulders, concrete, wood and on the shells of sea creatures such as limpets, mussels and barnacles.It can also be attached to other seaweeds.
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Physical Description

Type Information

Type locality: Scotland: Easdale, Argyll
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Source: AlgaeBase

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Ecology

Habitat

Depth range based on 19 specimens in 1 taxon.
Water temperature and chemistry ranges based on 2 samples.

Environmental ranges
  Depth range (m): 0 - 1.25
  Temperature range (°C): 11.855 - 12.348
  Nitrate (umol/L): 4.729 - 6.151
  Salinity (PPS): 35.184 - 35.363
  Oxygen (ml/l): 6.128 - 6.151
  Phosphate (umol/l): 0.351 - 0.418
  Silicate (umol/l): 2.578 - 3.285

Graphical representation

Depth range (m): 0 - 1.25

Temperature range (°C): 11.855 - 12.348

Nitrate (umol/L): 4.729 - 6.151

Salinity (PPS): 35.184 - 35.363

Oxygen (ml/l): 6.128 - 6.151

Phosphate (umol/l): 0.351 - 0.418

Silicate (umol/l): 2.578 - 3.285
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

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 Purple laver is highly adaptable to conditions on different parts of the rocky shore and able to withstand prolonged periods of exposure to the air as well as tolerating a greater degree of wave action than most other red algae. It occurs singly or in dense colonies throughout the intertidal but most frequently at upper levels.
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Life History and Behavior

Reproduction

The blade that you see on the shore is the gametophyte phase.In Porphyra umbilicalis the male and female gametangia are usually on separate blades. Sometimes they are on the same blade but separated.The blade phase is just a part of the life history. There is a separate, microscopic phase which lives in shells and is called the conchocelis phase.Look for pink patches on shells because these might be evidence of conchocelis.
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Molecular Biology and Genetics

Molecular Biology

Barcode data: Porphyra umbilicalis

The following is a representative barcode sequence, the centroid of all available sequences for this species.


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Statistics of barcoding coverage: Porphyra umbilicalis

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 59
Specimens with Barcodes: 73
Species With Barcodes: 1
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Wikipedia

Laver (seaweed)

Seaweed, laver, raw
Nutritional value per 100 g (3.5 oz)
Energy146 kJ (35 kcal)
Carbohydrates5.11 g
- Sugars0.49 g
- Dietary fiber0.3 g
Fat0.28 g
Protein5.81 g
Vitamin A equiv.260 μg (33%)
- beta-carotene3121 μg (29%)
Thiamine (vit. B1)0.098 mg (9%)
Riboflavin (vit. B2)0.446 mg (37%)
Niacin (vit. B3)1.47 mg (10%)
Pantothenic acid (B5)0.521 mg (10%)
Vitamin B60.159 mg (12%)
Folate (vit. B9)146 μg (37%)
Vitamin C39 mg (47%)
Vitamin E1 mg (7%)
Vitamin K4 μg (4%)
Calcium70 mg (7%)
Iron1.8 mg (14%)
Manganese0.988 mg (47%)
Phosphorus58 mg (8%)
Potassium356 mg (8%)
Sodium48 mg (3%)
Zinc1.05 mg (11%)
Link to USDA Database entry
Percentages are roughly approximated
using US recommendations for adults.
Source: USDA Nutrient Database

Laver is an edible, littoral alga (seaweed), and has a high content of dietary minerals, particularly iodine and iron. Laver is predominantly consumed in East Asia, where it is known as zicai in China, nori in Japan, and gim in Korea. In Wales, laver is used for making laverbread, a traditional Welsh dish. Laver as food is also commonly found around the west coast of Britain and east coast of Ireland along the Irish Sea, where it is known as slake.[1]

It is smooth in texture and forms delicate, sheetlike thalli, often clinging to rocks. The principal variety is purple laver (Porphyra umbilicalis).[2] Purple laver is classified as a red alga, tends to be a brownish colour, but boils down to a dark green pulp when prepared. It is unusual amongst seaweeds because the fronds are only one cell thick.[3][4] The high iodine content gives the seaweed a distinctive flavour in common with olives and oysters.[5]

Ulva lactuca, a green alga, also known as sea lettuce, is occasionally eaten as green laver, which is regarded as inferior to the purple laver.[6]

Cultivation[edit]

Laver cultivation as food is thought to be very ancient, though the first mention was in Camden's Britannia in the early 17th century.[7] It is plucked from the rocks and given a preliminary rinse in clear water. The collected laver is repeatedly washed to remove sand and boiled for hours until it becomes a stiff, green mush.[8] In this state, the laver can be preserved for about a week. Typically during the 18th century, the mush was packed into a crock and sold as "potted laver".

Laver and toast

Cultivation of laver is typically associated with Wales, and it is still gathered off the Pembrokeshire and Carmarthenshire coasts,[9] although similar farming methods are used at the west coast of Scotland.

Laver can be eaten cold as a salad with lamb or mutton. A simple preparation is to heat the laver and to add butter and the juice of a lemon or Seville orange. Laver can be heated and served with boiled bacon. It is used to make the Welsh dish known as laverbread.

Laverbread[edit]

Laverbread (Welsh: bara lafwr or bara lawr) is a traditional Welsh delicacy made from laver. To make laverbread, the seaweed is boiled for several hours, then minced or pureed. The gelatinous paste that results can then be sold as it is, or rolled in oatmeal; it is generally coated with oatmeal prior to frying.

Laverbread is traditionally eaten fried with bacon and cockles as part of a Welsh breakfast. It can also be used to make a sauce to accompany lamb, crab, monkfish, etc., and to make laver soup (Welsh: cawl lafwr).[10] Richard Burton has been quoted as describing laverbread as "Welshman's caviar".[11]

Laver is often associated with Penclawdd and its cockles, being used traditionally in the Welsh diet and is still eaten widely across Wales in the form of laverbread. In addition to Wales, laverbread is eaten across the Bristol Channel in North Devon, especially around the Exmoor coast around Lynmouth, Combe Martin and Ilfracombe. In North Devon it is generally not cooked with oatmeal and it is simply referred to as 'Laver' (lay-ver).

Laver is highly nutritious because of its high proportions of protein, iron, and especially iodine. It also contains high levels of vitamins B2, A, D and C.

See also[edit]

References[edit]

  1. ^ "British food seaweeds". http://everything2.com. Retrieved 6 May 2012. 
  2. ^ "Algaebase :: Species Detail". www.algaebase.org. Retrieved 2008-08-10. 
  3. ^ "laverbread – WalesOnline". www.walesonline.co.uk. Retrieved 2008-08-10. 
  4. ^ Wells, Emma (2010), A Field Guide to the British Seaweeds, National Marine Biological Analytical Quality Control Scheme (p 24).
  5. ^ "Laver nori". www.hospitalityinfocentre.co.uk. Retrieved 2013-11-01. 
  6. ^ "BBC – Science & Nature – Sea Life – Fact files: Sea lettuce". www.bbc.co.uk. Retrieved 2008-08-10. 
  7. ^ Mason, Laura (2008-05-20). "Great British Bites: laverbread – Times Online". London: www.timesonline.co.uk. Retrieved 2008-08-10. 
  8. ^ "Laverbread Parsons Pickles » Home". laverbread.com. Retrieved 2008-08-10. 
  9. ^ Don, Monty (2001-11-11). "Down your way". The Observer (London). Retrieved 2008-08-10. 
  10. ^ "Traditional Welsh Recipes". welsh-recipes.the-real-way.com. Retrieved 2008-08-13. 
  11. ^ "Black Mountains Breakfast — Brecon Beacons National Park". www.breconbeacons.org. Retrieved 2008-08-10. 

Bibliography[edit]

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