After much teasing and titillation, my urchin larvae have finally gotten down to the serious business of metamorphosis. It seems that I had jumped the gun on proclaiming them competent about a week ago, or maybe they were indeed competent and just needed to wait for some exogenous cue to commit to leaving the plankton for…
Tag: marine invertebrates
Crab feed(ing)!
Anybody who has visited one of the sandy beaches in California has probably seen kids running around digging up mole crabs (Emerita analoga). These crabs live in the swash zone at around the depth where the waves would be breaking over your ankles, moving up and down with the tide. They are bizarre little creatures,…
Competence
In the parlance of invertebrate zoologists, competence is the state of development when a larva has all of the structures and energy reserves it needs to undergo metamorphosis into the juvenile form. In the case of my sea urchins, this means that they have four complete pairs of arms, each with its own skeletal rod, and…
Wasting leather (star)
Until recently I hadn’t closely observed what it looks like when a leather star (Dermasterias imbricata) succumbs to wasting syndrome. When I had the outbreak of plague in my table almost 18 months ago now, my only leather star was fine one day and decomposing the next, so I didn’t get to see what actually happened…
Off to the races!
Yesterday I drove up the coast to Pigeon Point to do a little poking around. I had originally planned to search for little stars, survivors that had made it through the most recent outbreak of wasting syndrome. But I got distracted by other things and gave up on the stars, for now. I need to…
Larvae as . . . particles?
On another glorious afternoon low tide the other day, with the help of a former student I collected six purple urchins, Strongylocentrotus purpuratus. Given that we’re in about the middle of this species’ spawning season, I reasoned that collecting six gave me a decent chance of ending up with at least one male and one…
A whole lotta pink
The temperate rocky intertidal is about as colorful a natural place as I’ve seen. Much of the color comes from algae, and in the spring and early summer the eye can be overwhelmed by the emerald greenness of the overall landscape due to Phyllospadix (surf grass, a true flowering plant) and Ulva (sea lettuce, an alga)….
Monsters in the making
Yesterday I collected three very small Pycnopodia helianthoides stars. When I brought them back to the marine lab I decided to photograph them because with stars this small I could easily distinguish between the original five arms and the new ones: These guys began their post-larval life with the typical five arms you’d expect from…
Fouling communities
On 11 March 2011 a magnitude 9.0 earthquake occurred off the coast of Japan. About 14 hours later, at 11:15 a.m. local time a tsunami came through the Santa Cruz Small Craft Harbor. It sank dozens of boats and significantly damaged several of the docks. People were ordered to evacuate the area before the expected…
Motherhood, snail style (Part 2)
It has been almost a month since my big female whelk started laying her eggs, and the embryos seem to be developing nicely. The first time I witnessed this phenomenon I saw the egg capsules begin to turn black, and worried that the eggs inside were dead and decomposing. But the cool thing about Kelletia…