Spiral Wrack (Marine Algae of Cape Cod, Massachusetts and Adjacent Islands)

Spiral Wrack

Fucus spiralis

Summary ⁷

Fucus spiralis is a species of seaweed, a brown alga (Heterokontophyta, Phaeophyceae), living on the littoral shore of the Atlantic coasts of Europe and North America. It has the common names of spiral wrack and flat wrack.

Description ⁸

An intertidal brown seaweed, found on the high shore. It grows up to 40 cm long, without air bladders and lives for up to 4 years. The species can tolerate a high level of desiccation. Fronds have a characteristic ridge along the edge of the receptacles.A number of discrete forms of this species have been recorded. In the UK, a diminutive form Fucus spiralis nanus is relatively common.

Taxon biology ⁹

Spiral wrack is a small version of bladder wrack, but it doesn't have inflated bladders. The bladders that you may see have a jelly-like content and are for reproduction. The bladders have a narrow rim which is lacking by bladder wrack. This brown seaweed grows in the highest part of the tidal zone, often underneath Blidingia minima. Spiral wrack is fairly common in the delta region and the Wadden Sea.

Habitat ¹⁰

Fucus spiralis attaches to rocky substrata on sheltered to moderately exposed shores. It lives on the upper shore below the zone of Pelvetia canaliculata and above Fucus vesiculosus and Ascophyllum nodosum.

Habitat ¹¹

Depth range based on 90 specimens in 2 taxa.
Water temperature and chemistry ranges based on 14 samples.

Environmental ranges
  Depth range (m): 0 - 1.25
  Temperature range (°C): 11.471 - 12.348
  Nitrate (umol/L): 4.729 - 7.121
  Salinity (PPS): 35.184 - 35.363
  Oxygen (ml/l): 6.069 - 6.200
  Phosphate (umol/l): 0.336 - 0.439
  Silicate (umol/l): 2.315 - 3.285

Graphical representation

Depth range (m): 0 - 1.25

Temperature range (°C): 11.471 - 12.348

Nitrate (umol/L): 4.729 - 7.121

Salinity (PPS): 35.184 - 35.363

Oxygen (ml/l): 6.069 - 6.200

Phosphate (umol/l): 0.336 - 0.439

Silicate (umol/l): 2.315 - 3.285

Note: this information has not been validated. Check this note. Your feedback is most welcome.