Kelp Photo Gallery
These photos were taken in Halifax County, N.S., and most show the most easily visible subtidal kelp (to a snorkeler), Laminaria Agardhii. This ruffled kelp is the species that I've seen washed ashore on the same beach since the 1960s. What looks different now is the pale appearance of the fronds, especially the ruffled edge, and the tattered appearance of the plants. Although the evidence I offer here is merely 'anecdotal,' 20-30 years ago most of this kelp that washed ashore here in summer was a deeper brown, with intact ruffled edges. Literature on kelp farming or 'mariculture' describes two syndromes known to affect kelp when it is cultivated in suboptimal conditions: 'green rot' results from inadequate light and 'white rot' results from too much light or too little nitrogen. Brown seaweeds that cannot build the normal concentration of the brown pigments will appear greenish, since the green pigment, Chlorophyll a is the basic pigment that underlies all of the other colors that plants develop. At the distal edges of these plants, the palest kelp tissue is also seen to be turning red, reminiscent of the 'sunburn' affecting rockweeds here. Inadequately fertilized plants of all types are more susceptible to the damaging effects of light.
All photos copyright Debbie MacKenzie. Reproduce them if you like, just please credit the source.