Journal archives for September 2022

25 September, 2022

A great biodiversity of seaweeds thrown up on Cardiff State Beach, California

I am currently in Southern California for 16 days, centered in San Diego County, in Encinitas, at Moonlight Beach.

I like to visit Cardiff State Beach (aka Cardiff Reef) because several years ago that area used to be very good for shells. Back then the majority of the shells were cast up on the southern shore of the channel where the San Elijo Lagoon runs into the Pacific Ocean and the beach immediately south of there. It was the much-loved late iNatter @finatic who discovered how rich the shell diversity was there by checking all of the State Beaches one by one.

More recently a lot of construction was carried out in the estuary and the lagoon, and that disturbed the whole ecosystem quite seriously. However, I think/ I hope the area seems to be very slowly recovering.

I already knew that the shells mostly tended to wash up on the southern shore of the outlet of the San Elijo Lagoon (the northern tip of the area known to surfers as "George's"), but for some reason the great majority of the seaweed that washes up seems to land on the opposite side of the channel (the southern tip of the area known to surfers as "Cardiff Reef").

I had also casually noticed before that there appeared to be a striking degree of biodiversity within the algae and marine plants that wash up there. I imagine a lot of the seaweed grows on Cardiff Reef, a rocky platform which is just offshore.

So anyway, I decided to try to concentrate on making observations of all of the algae, especially those that seemed unfamiliar. In the process I was able to find a lot of species that were new to me, thanks to the generosity and exceptional ID-ing skills of @hfb, Heather Fulton Bennett.

Of course I already knew about the presence there of Giant Kelp and Feather Boa Kelp, as well as Torrey's Surfgrass. I had also observed the Southern Surf Palm, and Stephanocystis dioica, as well as some pretty smaller red species like the Common Coralline, the Sea Comb, and a species of Callophyllis, as well as a very decorative Ulva species, known as the Sea Spiral, Ulva taeniata.

But as well as those nine common and mostly rather distinctive species, I found an additional seven cool ones that were new-to-me. Note that three of the species do not have a common name.

Oarweed, Laminaria farlowii. Note: this is not the same oar weed species as in Europe. So far there are only 27 observations of this species on iNat.

Devil Weed, Sargassum horneri, an invasive species from Japan and Korea.

Banded Fanweed, Zonaria farlowii. I found several clumps of this species.

Nienburgia andersoniana. So far this species has a total of only 24 iNat observations worldwide.

Dictyopteris undulata. It looks as though this species only occurs from Point Conception south to Ensenada.

Neogastroclonium subarticulatum (maybe).

Also I twice found something in the Order Gracilariales, which I have not found in California before.

So that makes at least six ID-ed species that were new to me. Pretty great. And species 1 and 4 are either rare or only very infrequently observed in general, so that is really great too!

A lot of fun all round!


Posted on 25 September, 2022 16:07 by susanhewitt susanhewitt | 0 comments | Leave a comment