16 Nov 2007

Laminaria digitata

Laminarian digitata's habitat is the rocky seabed below the low tide line: you will see Laminaria 'plantations' only at the very lowest spring tides. This specimen was torn up by the recent stormy weather and washed ashore. Top to bottom: fronds, stipe (stalk) and holdfast.
Below: closeup of the holdfast. The Laminaria forces tough anchoring filaments into the rocky seabed. The holdfast is also home to a colony of small barnacles and red algae.
Tonnes of Laminaria at the high water line.
A red seaweed (Rodophyceae sp.) growing on a Laminaria stipe.


Cliff Thornton said...

About 1970 I used to collect samples of Laminaria from RHB for a research project. Normally the plants were pretty clear of epiphytes because of the in-shore turbidity of the water. The long stipes and epiphytes on these Laminaria suggests that they were growing quite a way off shore. Unless the coastal erosion has ceased in the last 30 years and the sea is cleaner?
Essex, U.K.
(almost near Paglesham!)

Peter McGrath said...

Hi Cliff, good to hear from you. That lot was washed up following a prolonged bout of northerlies, so could easily have come from offshore.

The coast is still eroding pretty briskly, and usually more brown that limpid blue. Were you at the late (lamented) Leeds University Marine Lab at Bay?

(The yacht on which I have many happy memories was Rose of Paglesham, one of the Shuttlewod boats).

Cliff said...

Like you I was a graduate of Liverpool. I did most of my field work at Port Erin on the Isle of Man. But the NERC project I was working on meant that I had to collect Laminaria samples from RHB. I also collected seawater from Souter Point near Sunderland, it was almost black with coal dust. I understand that the Durham coast has cleared up in the last few decades since the coal mines stopped tipping their waste straight into the sea.