Admittedly I’m not much of an algae person (go vertebrates!), but when Emily talked about the “fairy rings” when we went on our crack-of-dawn field trip to Cattle Point I started to think about algae. After a bit of searching on Bing, I was directed to a FHL marine botany page, of all places, that talked about the “fairy rings”.
These mysterious clusters of algae are the product of Endocladia muricata. This alga prefers the mid intertidal to high intertidal zone and is common all along the west coast. Its more of a rocky shore alga, that can grow so think it forms a carpet. Endocladia muricata is a very competitive species while at the same time offering shelter for others and is surprisingly durable, it can withstand the heat of the beating sun during summer low tides and the chillness of the winter. No wonder its natures Brillo pad.
Given that we’ve covered the topic of life cycles in class I feel that I must include some life history for this special alga. “Endocladia muricata has an isomorphic life history, meaning that the gametophyte and sporophyte have the same morphology. In the intertidal, the tetrasporophyte phase is found more often than the gametophyte phase.” (FHL marine botany) and “In the field, reproductive Endocladia can be identified by the yellow tips which contain cystocarps. The dark bulges in the branches contain cystocarps. The transparent, yellow bulges are pericarps that have released their zygote.” (FHL marine botany). This sounds fairly complex, I know. But its actually interesting.
Now to the important part, how and why on earth does this alga spread out in to the said “fairy rings”. It seems that: “hydrated fronds have a lower thermotolerance but spend more time photosynthesizing. Fairy rings are formed by the differential thermotolerance of fronds as a function of their location within the clump of Endocladia muricata. Inner fronds stay hydrated longer allowing the fronds to photosynthesize more but have a lower thermotolerance.Thus inner fronds are taller but are also more likely to die during hot day. Outer fronds are shorter but are able to survive on hot days. When Endocladia is exposed during a low tide that coincides with high air temperatures, fairy rings can form” (FHL marine botany). So pretty much as the sun singes the alga, the inner part shrivels up due to its moisture while the plants outer edges are more crisp to begin with, it stays relatively the same. This process creates the ring of surviving alga that we fondly call “fairy rings”. Just don’t confuse this supernatural event with the terrestrial one that involves mushrooms.
Yours from the tidal zone, Liza.
(Here is the link if you want to do some research on your own http://depts.washington.edu/fhl/mb/Endocladia_Laura/Endocladia_home.html )