I return to the field

For a number of reasons–a lingering injury to my bum knee, scheduling difficulties, and ongoing postconcussion syndrome–I missed the autumn return of the minus tides. At this time of year the lowest tides are in the afternoon, and at the end of the day I just didn’t have the energy to deal with field work. It took until today, the winter solstice, for me to find my way back to the intertidal. An additional motivating factor was a request from both the Seymour Center and Seacliff State Beach for critters to populate their displays. So off I went!

Over the past day or so a storm system blew through the area. It didn’t drop any rain on us in Santa Cruz, but earlier this week the National Weather service issued a small craft advisory and suggested that people stay off the beach, due to a combination of big swell and high tides. Usually when I go collecting at Davenport I go to the reef on the north end of the beach, which has more varied vertical topography and a similar, but generally richer, biota than the gently sloping benches to the south. However, the big swell had washed away a lot of the sand, leaving the beach steeper than it would be in the summer, and even the -1.0 ft tide didn’t make the reef safely available to someone not clad in a wet suit.

So I trudged across the beach and went to the south instead. It gave me an excuse to poke at the stuff that had been washed up onto the beach and look for nice pieces of algae to take to the Seymour Center. Algal pickings are rather slim in the winter, but I did find several decent small clumps that will do nicely in the touch table. One noteworthy find was a dead gumboot chiton (Cryptochiton stelleri). There were four such corpses washed up on the beach, in varying states of decay and stench.

Cryptochiton stelleri is the largest of the chitons, routinely growing to length of 20 cm. It’s a hefty beast, too. The chitons as a group have their greatest diversity in the intertidal, but Cryptochiton is a subtidal creature. Unlike the intertidal residents, Cryptochiton‘s sticking power is pretty weak. Living below the worst of the pounding of the waves, it generally doesn’t have to cling tightly to rocks. However, because it doesn’t stick very well, Cryptochiton often gets dislodged by strong surge, especially during spring tides. Then they get tumbled by the waves and wash up dead on the beach. I don’t think I’ve ever seen a live Cryptochiton washed up.

The reef to the south of the beach consists of flat benches that slope down to the ocean. There are some channels and a few pools, but otherwise there is no real topography. Of course, for creatures living in the intertidal, there is topography–the nooks and crannies, as well as vertical faces, provide a variety of microhabitats.

Mopalia lignosa is one of the intertidal chitons that I’m always delighted to find because it’s not as common as some of the others, and it’s a beautiful animal. The species epithet lignosa means ‘wood’ and refers to the patterning on the dorsal shell plates.

As usual, there were spectacular anemones to be seen. And I saw something new! Anthopleura sola, the sunburst anemone, is one of the large aclonal anemones that is very common. At Natural Bridges there is a brilliant fluorescent A. sola in a pool on one of the benches I visit. I’ve been keeping an eye on this animal for a couple of years now, just to reassure myself that it’s still there and doing well. The animal is hardly hidden, but it feels like a little insiders’ secret that not everybody knows about.

For the first time, I saw fluorescent A. sola at Davenport Landing. Three of them, in fact! And boy, were they all bright!

The third fluorescent anemone was closed up. There were just enough partial tentacles visible to see that it is indeed a fluorescent specimen.

Now, I don’t spend as much time at the south end of the beach as I do on the north side, but until today I had never noticed these fluorescent animals. Could I have missed them all this time? It’s kind of hard to miss a neon green animal the size of a cereal bowl! At any rate, now that I know they exist and hopefully remember where they are, I’ll be able to keep an eye on them, too.