Skip to content

As if the plague weren’t enough

Today is Monday.

Last Friday morning I was at the marine lab doing my usual feeding and cleaning stuff, and everything was fine. I was back at the lab Friday afternoon to return some animals that we had borrowed for one of the classes I'm teaching, and as soon as I got out of the car I knew something was wrong. I could smell it. Plankton bloom.

When I opened the door to one of the wet labs, it felt like walking into a wall of stench. It is a peculiar smell of excessive fecundity, which we occasionally see at the lab this time of year, due to a rapid population increase, or "bloom," of one or a few phytoplankton species. I'm not sure if the smell is actually bad or if it just seems bad because of all the negative things I associate with it. Negative things such as:  Sludge accumulating and decomposing on any horizontal surface in a table, including the surfaces of animals; said animals being fouled and dying because their respiratory surfaces are gunked up; seeing water straight from the tap coming in brown.

But whenever we get a nasty bloom like this, I am always curious about which critter it actually is. Back in the summer of 2010 there was a phytoplankton bloom in Santa Cruz that was at least partially caused by a dinoflagellate in the genus Alexandrium, some of which are known to produce toxins that work their way up the food chain and cause paralytic shellfish poisoning in people.

I took a sample from some build-up from this current bloom and looked at cells under the microscope (fun!). I was able to identify a couple of dinoflagellates right off the bat.

This is Ceratium.  I saw a lot of cells that look like these:

Ceratium cells.
Ceratium cells.
© Kudela lab, UCSC

Various species of Ceratium are present in plankton tows most of the year and as far as I know are pretty innocuous.

I also saw lots of these cells, too. This is Prorocentrum, a dinoflagellate that is pretty easy to recognize because of the little spine at one end of the cell. I don't think these guys are toxic, either.

Prorocentrum cells. ©2013 Allison J. Gong
Prorocentrum cells.
© 2013 Allison J. Gong

Lastly, there were a lot of these cells. I wasn't able to get a very good look at them and don't know for sure who they are, but they may be a species of Cochlodinium polykrikoides. I saw single cells and chains of two cells. C. polykrikoides is not nearly as harmless as the other two algae I saw. It has been responsible for fish kills in Asia.

These cells in a short chain might be Cochlodinium polykrikoides. ©2013 Allison J. Gong
These cells in a short chain might be Cochlodinium polykrikoides.
© 2013 Allison J. Gong

On my way out of the marine lab yesterday I stopped by the overlook to see what the surf looked like. I could see that the water was discolored with a brownish tinge. Look at the water as it recedes from the rocky bench. It would normally be white, but here it is kind of a dirty gray-brown color.

The good news is that today, Monday, the bloom seems to have abated quite a bit. I cleaned all of my tables and tanks on Saturday (extremely gross) and Sunday (not nearly as gross) and this morning there wasn't very much sludge at all. And the smell was nothing like it had been on Friday afternoon. So maybe we're getting a reprieve and won't have to deal with weeks and weeks of this stuff. That would be nice. My poor animals need a break from environmental conditions that are trying to kill them.

4 thoughts on “As if the plague weren’t enough

  1. Ralph Wolf

    Is your water table supplied by water from the Monterey Bay? If so, please describe if/how it is filtered or otherwise treated. Have you recently introduced any new specimens to your water table from the wild? What do you feed your sea stars? What is the origin and how is it processed?

    Since your outbreak is reasonably correlated in time with observations of disease reported by local scuba divers, a quick analysis of what they have in common may help to identify or rule out possible causes and routes of transmission.

    BTW, If you need a few experienced divers with general engineering/science backgrounds to help with field work, such as photographing evidence in the wild, collecting samples, or reporting depth-temperature profiles from various local dive sites, I'd be happy to help round them up.

    1. algong

      Yes, the water comes directly from Monterey Bay. The water that feeds my building passes through a sand filter but otherwise isn't treated. My collection of stars has been static for years, with no new additions for quite some time. Their food is food-quality fish, squid, and prawn, supplemented by the occasional mussel to give them something fun to do.

      The red tides are not a new phenomenon at all. In fact, I sort of expect one in the late summer or early fall, especially if the water temperature has been elevated for a while. Occasionally we get a plankton bloom in the winter, which I suspect may be correlated with when the agricultural fields are fertilized. I haven't looked into that, though.

      Thank you for your offer to volunteer some divers to help figure out what's going on with the stars. At this point, I'd like to see photos of the melting stars in Monterey Bay; all the divers who have told me they've seen the stars didn't have cameras with them on the dives. And if they know what species they see being affected, that would be useful as well.

  2. Ralph Wolf

    I've uploaded about 100 pictures from Monterey Bay on 10/11/13 to

    If you want to download the whole set, with temperature & depth profiles grab the zip file from

    I see at least 2 species involved. Giant Spined Stars and one or more of the Sun Star varieties, but I'm sure you'll see much more than I do in these photos. Please share your observations & guesses as to what is going on!


What do you think?

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: