UC Davis math professor and Hero of Intellectual Freedom Abby Thompson sends us some intertidal photos (with one mammal). Abby’s IDs and captions are indented, and you can enlarge the photos by clicking on them.
And don’t forget to send in your photos!
A late summer entry from the tidepools, including a mystery through the microscope:
First, two handsome chitons: these are the fellows who cling to rocks like a limpet, and, if dislodged, curl up like a pill-bug to protect their soft undersides:
(Lepidozona mertensii) Merton’s Chiton:
(Mopalia lignosa) Woody chiton:
Genus Themiste (peanut worm); the species is uncertain. The body of the worm lies below the sand. The tentacles are very active (and very skittish), sweeping in particles towards the mouth:
I’ve posted some pictures of the deer that often come down to the beach before dawn. The cliffs down to the beach are quite steep in places, and sadly sometimes the deer slip and fall. This must have been a fawn (based on size). Skip the next picture if you’re not a nature-tooth-and-claw person:
Dead deer- probably a mule deer, Odocoileus hemionus:
Diaulula odonoghuei (Northern leopard dorid): This species is typically further north, although I’ve found it here a few times:
The next three photos are a puzzle to me, maybe some readers have a suggestion. They’re through a microscope. I was looking at bryozoans on a piece of kelp, when I noticed some ring-like things on stems growing out of the bryozoans. The first picture is a side view showing the stems. In the second picture you can see the (greenish) rings forming inside one of the bryozoans- the rings seem to turn peachy as they mature. The final picture shows the mature rings from above. Inaturalist hasn’t come up with a suggestion so far. From what I’ve read of marine bryozoans, I don’t think this is part of their reproductive cycle. A tentative suggestion from the Bodega Marine Lab (thanks!!) is “stemmed diatoms”; the world is a mysterious place:
Triopha maculata– a particularly handsome nudibranch:
Gotta say, I feel kinship with those bryozoa
😁
I did my PhD research on marine bryozoans and spent many hundreds of hours (perhaps even thousands of hours) peering down a microscope at living colonies. I don’t remember ever seeing anything like your greenish rings, although I did see plenty of organisms growing on and inside the zooids that took me some time to identify. I can say with some confidence that your structures are nothing to do with the bryozoan reproductive system. I’ve never heard of such a thing as a “stemmed diatom”, although I’m no expert on microalgae and can’t absolutely say that no such thing exists. A very tentative guess would be that your greenish structures are fungi of some sort, perhaps initially growing inside the zooids and then pushing their way out on stalks to release their spores. I’m retired from bryozoology now but still keep an interest in these animals, so if anyone can give a more definite identification, I’d love to hear it!
Fungi was another suggestion from the marine lab, but I could find even less info on that than on “stemmed diatoms”….
Always interesting!
So I looked at Bryozoa, and as expected I found nothing helpful. But there is this figure from Ernst Haeckel with some fanciful details that look sort of similar: https://commons.wikimedia.org/wiki/File:Haeckel_Bryozoa.jpg
I found stalked diatoms, but they don’t really look like those stalked things.
Chitons are so cool. And so are nudibranchs! And bryozoa. The first I’d ever heard of them was as a paleontology student. They have an excellent, and long, fossil record. I’ve collected them from the Devonian.
I’m in Davis and would love to know where these were taken. I’m assuming up the coast towards Mendocino?
At Dillon Beach- if you walk north from the main beach you get to rocky coast pretty quickly, with lots of rocks exposed at low tide.
Thank you for another fabulous dive into marine invertebrate world!
Thanks all for the interesting replies and kind words!