Archive for February, 2015

Sea urchin fertilization & development

February 26, 2015

Purple urchin2In second year Biology we are currently studying reproduction and although our focus is human reproduction, sea urchins are a wonderful model to study. Pearson College divers collected about 40 purple sea urchins (Strongylocentrotus purpuratus) and brought them back to the floating lab. In Biology class we injected them with potassium chloride which causes them to release their eggs or sperm.

Urchin sperm

I have done this lab many times and in many locations and I am very pleased to say that this time was my most successful! The first urchin I injected released many healthy eggs. This is where my luck usually changes because without sperm, eggs are useless. I asked students to choose a male urchin (there is no way to tell by looking at them, so it takes some luck). Bader chose one and very soon after being injected streams of sperm came out of the gonopores!!

Urchin sperm2

Students then took a sample of eggs to look at under the microscope then added sperm in order to watch fertilization.

2h Two cells D

Photo above at 2 hours post-fertilization. All of the eggs are fertilized and a few are at the two-cell stage.5h two four eight D

At 5 hours post-fertilization, there are some two-cell stage embryos but most are at the four-cell stage.

10h blastulae C

At 10 hours, we had blastulae with big cells, still in their fertilization membranes.

21h blastulae D

At 21 hours, blastulae with smaller cells, still in their fertilization membranes.

26h spinning blastula A

At 26 hours, some of the blastulae hatched out of their membranes and started spinning.

6 days A7 days B 7 days CAt 6 and 7 days post-fertilization, we had pluteus larvae!

All of the urchin larvae have now been released into Pedder Bay with warm wishes for a long kelp-ful life!

See for more photos.

Deep sea costumes 2015

February 20, 2015


Here are the latest deep sea organisms to visit Pearson College… this time on Wednesday 21 January and Thursday 22 January 2015.

This year the specimens included:

P1040166 Prince Axel’s wonderfish

P1040183 A tube-eye or thread-tail fish

P1040179 Crown jellyfish

P1040178Barreleye fish

P1040173 Chubby flashlight fish

P1040171 Deep sea glass squid

P1040168 Umbrella mouth gulper

P1040204 A stoplight loosejaw fish

P1040208 A dragonfish

P1040207 A gulper eel

P1040206 Venus’s flower basket sponge

P1040205and a basket star.

A low tide for comparison

February 17, 2015

As promised, here are some photos of a low tide (0.6 m on Sunday 15 February 2015) for comparison to the very high tide on 10 December 2014.





P1040331 P1040332

Tide guage    P1040337

River otter found dead under workroom

February 13, 2015


Jeff, our temporary Facilities Maintenance Technician, found the smelly carcass of a river otter next to the base of the faculty workroom yesterday morning and thought of me (which I feel is a real compliment!).P1040323