Rockweed Photo Gallery

Changes in rockweeds (Ascophyllum nodosum and Fucus species) in Nova Scotia have been described in several articles on this website. In other coastal areas of the North Atlantic (including Iceland and Europe) these common brown seaweeds have been noted to be in decline recently. According to standard literature on these plants, they normally live for several years until they attain a size such that they are torn from the rocks by winter storms, or removed by ice scour. Observations in Nova Scotia today, however, seem to show these plants breaking down due to other environmental stresses: light, wind, nutrient shortage. In areas with higher nutrient availability (either due to terrestrial input sources or greater wave action) rockweeds show greater resistance, but in the clean, sheltered areas, the parts of the natural habitat that normally offer the lowest nutrient availability, these seaweeds can now commonly be seen to be dying on the rocks. Older Fucus can become so thin and withered that the 'drag' exerted by storm wave movement is insufficient to tear them off - and totally 'skeletal' older specimens can be seen still attached to the rocks among the younger ones.

(links to other seaweed galleries: green seaweeds - kelp - fuzzy seaweed - Irish moss - barnacles )
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Late summer, Ascophyllum extremely yellowed in sheltered East Dover, except in the immediate vicinity of a small sewage outfall.

Another small sewage outfall on the far shore results in darker colored rockweed interrupting the otherwise yellow seaweed belt.

Midsummer, 2001, cool-normal temperatures, yet rockweed has prominent "heat-damaged" patches. This is a relatively new sight here.

Spring, 2002, upper edge of Ascophyllum belt in sheltered areas appears 'burnt.' Likely due to lowered resistance to dessication.

Subtidal mature fucus, withered to a brown 'skeleton.' With younger Fucus and very pale Irish moss, mid-summer(...this is my 'seasick' photo...)

Dark pigmentation of rockweed growing inside sewage-polluted Halifax Harbour.

Pale subtidal rockweed heavily colonized by filamentous epiphytes.

Yellowed subtidal Asco, with deteriorating Fucus and yellow Irish moss and 'fuzzy' algae.

Pale rockweed on unpolluted beach, heavily overgrown by brownish 'fluff.'

Extremely withered Fucus low on a beach at Belliveau's Cove, N.S., September, 2001.

White 'hairs' develop on higher-positioned intertidal Fucus under conditions of nutrient shortage. (This is visible most of the year.)

Low intertidal Fucus in sheltered area at Prospect, N.S., extreme withering of older specimen and 'yellow and red' appearance of younger ones.

Subtidal Fucus vesiculosis also shows some degree of 'hair' development, and low pigmentation. Prospect, N.S.

Small rockweed showing consistent length of frond breakage, most likely due to wave action. Another sign of weakness in this plant?

Rockweeds commonly wash ashore with all of the mature tissue shrivelled to thin dark strips. Unusual, compared to drift seaweed gathered in the past.

Extreme withering of older rockweeds is now very visible along this shoreline.

'Singed' appearance of fine yellowed Ascophyllum in spring, near Peggy's Cove, N.S.

More 'singed' Ascophyllum, spring, 2002, Prospect, N.S.

All photos copyright Debbie MacKenzie. Reproduce them if you like, just please credit the source.

(links to other seaweed galleries: green seaweeds - kelp - fuzzy seaweed - Irish moss - barnacles )
Photo gallery index

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