Spring Bloom Sampling in California

One of the reasons I haven’t posted for a bit besides the normal-busy routine is that it is Spring Time! What’s that got to do with anything you ask?


Me in the Anza-Borrego Desert next to an Ocotillo plant
Me in the Anza-Borrego Desert in California, next to a flowering Ocotillo plant

Besides blooms of flowers in the desert  (such as those in the Anza-Borrego Desert), we also get blooms of phytoplankton along the coast in Southern California.

Here, in the spring we get very high winds that can result in upwelling events in the coastal ocean, pushing waters offshore and bringing up cold, nutrient rich water from the bottom ocean layers to the top layers.

This increase in nutrients (such as nitrogen, phosphorous, iron, etc.) can result in massive ‘blooms’ or increases in specific phytoplankton species (diatoms, dinoflagellates, etc.), since typically their densities are limited by nutrient availability. During these blooms, whoever wins the space and resource competition will dominate… until they get run down by grazers, parasites or viruses.. or run out of their limiting nutrient. Once these species decline this then provides space/resources for the next dominating species.

Upwelling Diagram from Sanctuary Quest 2002, NOAA/OER
of Upwelling (Image from Sanctuary Quest 2002, NOAA/OER)

These upwelling events also offer AWESOME opportunities for scientists to examine the species dynamics, and the mechanisms that result in some species or functional groups of phytoplankton to dominate over others.

This year, our laboratory  (the Caron Laboratory at USC) decided to start our sampling period after we noticed strong winds on April 9th.. and I mean Strong! I was biking to my circus class that evening, and a branch literally flew and hit me.. luckily I was wearing a helmet 🙂  During lab meeting that week, we were all telling each other the horror stories of the strong wind, and realized.. ‘woah!’… we should start our spring sampling asap! So we quickly contacted the amazing Santa Monica Pier Aquarium (Heal The Bay) and received permission to use some of the space there to do our sample processing for three weeks. Then we finalized our schedules, rotating each daily to sample and process the water off of the Santa Monica Pier. Each day at 8:30am, we get to the aquarium, load up our cart with the RBR (an oceanographic instrument that measures temperature, salinity, chlorophyll and dissolved oxygen), a bucket and container for loading up sea water, and a 20 micron plankton net to collect a concentrated water sample. Then by 9am, we are loading up water into our collection container, and then rolling the water back to the aquarium to filter some of it down as fast as possible onto filters that we flash freeze for DNA/RNA extractions. We also preserve some of the whole sea water for relative abundance counts of the different organisms via microscopy, and we  sample the water for extraction of chlorophyll and domoic acid (toxin produced by some diatoms). Once we get back to the lab, we inspect the concentrated samples from the plankton net to get a quick overview of who is in the water, and who is the dominating species.


This year the sampling has been super interesting! It started off with a diatom and dinoflagellate bloom, and it looks like the diatoms have been CRUSHED by a parasitoid, Cryothecomonas spp.! Once the diatoms crashed, the dinoflagellates  increased more, in particular two species are currently dominating: Akashiwo sanguinea and Cochlodinium spp. (species will be determined after we get our molecular sequences back). I also found some tintinnid ciliates parasitized by Eudoboscquella parasitoids.. so beautiful.


In addition to using molecular sequences for identification of the different taxa, our laboratory also analyzes the RNA sequences (using bioinformatics) to examine gene expression of the different taxa that are increasing and decreasing during the bloom. These methods can help us determine when species are taking up specific nutrients, when they are multiplying, when they are stressed, and even if they are being attacked by parasites. Lastly, my work in particular during this spring bloom will examine the dynamics of these species and their parasites through time using qPCR (quantifies the relative number of the hosts and parasites by comparing samples to standard curves).

We have five more days left of daily sampling, and I will be sure to follow up with another blog on the results of this spring bloom sampling period. I will also post soon about the exciting results from a massive laboratory experiment that I just finished. Stay tuned!

Inspiring the Inner Parasitologist in Youth through Science Workshops

This weekend I had the awesome opportunity to spread my enthusiasm for parasites with  middle schoolers at a science workshop through the ‘LABs’ series at The Institute for Educational Advancement (IEA) in Pasadena, CA.

Some of the students and myself and the IEA LABs parasitology workshop that I gave this Saturday. I think all of us were super excited to detach the parasitic female and male isopods from the host mud shrimp!

IEA in Pasadena, CA, is an inspiring non-profit organization, that helps to identify and foster the individual talents and abilities of gifted students from all backgrounds, and works to serve and support them and their families. It was super neat to interact with these students and to reflect on the world of parasites with them.

My main learning objectives for the students in the workshop were to: 1) Define different types of ecological relationships, including the different types of symbiotic relationships; 2) differentiate among parasites, parasitoids and pathogens; 3) get acquainted with different parasite lifestyles- including direct transmission, vectored transmission, trophic transmission, parasitic castrators, host behavior modification, etc. 4) revel in the sheer shock and aw of diverse parasites; 5) become familiar with using microscopes; and 6) gain experience with some basic dissection techniques.

I found some super awesome and educational parasite videos during the process  of getting my interactive lecture together-including videos of: 

The tongue-eating parasitic isopod of fish

The sexual parasitism of the female deep sea anglerfish by the male deep sea angler fish

And of course parasitic wasp larvae developing inside of their host caterpillar: 

This was also a great opportunity to become more acquainted with local parasitologists and the common parasites and hosts in the Los Angeles area. This meant connecting with my local parasitologist colleagues (many of whom are part of the Southern California Society of Parasitologists) and finding some parasite ‘hot-spots’ so that I could bring in ample numbers of snails, crabs, shrimp and protozoans for some hands-on activities including dissections and mounting slides on the microscope.

Below was one of the students’ favorites – the parasitic isopod couple (yes.. male and female showing their love for each other all while parasitizing the host shrimp). ‘Couples that parasitize hosts together.. stay together!.. awww’

They were also amazed by the marine protistan parasitoid Parvilucifera sinerae, that they happened to catch in the act of bursting out of its dinoflagellate host (and thus killing its host!). I am particularly fond of this parasitoid right now.. since I’m working with marine plankton communities every day at USC. You can read about some of my current postdoc work here

The dinoflagellate, Lingulodinium polyedra, parasitized by the perkinsid parasitoid, Parvilucifera sinerae
The dinoflagellate, Lingulodinium polyedra, parasitized by the perkinsid parasitoid,    Parvilucifera sinerae

This event  reminded me that one of the main reasons why I love science is actually  the amazing support from other scientists.. and getting to know these scientists as people! For instance, I could not have done this workshop, without the support of Dr. Kevin Lafferty (USGS, UCSB) and Dr. Ryan Hechinger (Scripps-UCSD) who provided me with some hot spot localities for collecting highly-parasitized populations of the California Horn Snail, and how to access those hot-spots. These snails are parasitized by many different species of trematodes (Platyhelminthes), which are trophically transmitted parasites. This means that these parasites use multiple hosts to complete their life cycle and thus require their first set of hosts to be eaten by their final ‘definitive’ host. These parasites are also great for show-and-tell purposes since the cercariae (parasitic stage that searches for the next host) are larger than 100 um, move around quite a bit and can often have charismatic features, such as eye-spots.

I also got more great advice from Dr. Kimo Morris, a Professor at Santa Ana Community College and Dr. Ralph Appy regarding what other critters I could collect, and how to alter my workshop and lectures to appropriately target middle schoolers. Dr. Ralph Appy actually invited me to his laboratory to learn how he digests crabs and shrimps with an acidic solution to fool the parasites (in these hosts) into thinking that they are in the stomach of the next host of their life-cycle.. with the ultimate goal of collecting the parasites into a pool of liquid for research or show-and-tell. Dr. Ralph Appy provided me with a ton of ghost shrimp, mole crabs (sand-crabs) and the really cool mud shrimp that was parasitized by two ectoparasitic isopods (one female and one male).

All in all… I definitely learned a ton from this great opportunity.. and look forward to giving another parasitology workshop to K-12 students in the future (next time with fresher snails.. so they don’t smell so bad!).





If you build it, the weevils will come

Let’s face it – not everyday in the life of a scientist is filled with exciting and important discoveries. (And if this is not true for you – please share your secrets with me!)

Friday- My to-do list consisted of:

  1. Training a new undergraduate intern on processing frozen weevils (aka- smashing frozen weevils with plastic pestles in DI water) , and dissecting the weevil-mush (aka- homogenate) under phase contrast at 400x to look for microsporidia.
    • Footnote: Microsporidia by the way are hands-down the cutest parasites in the world. They are like little shiny hotdogs doing a waggle dance under the microscope. Then they become cooler if you imagine sunglasses on them. Ok.. I might be the only person that thinks this-  as several other researchers have voted for other parasites as #1 cutest…

Below is a photo of microsporidia (Nosema fumiferanae postvittana subsp.n.) from the Light Brown Apple Moth that I took during my PhD work. The mature spore form of the microsporidia in the weevil, Neochetina bruchi, look very similar under the microscope. .but so far I have not been finding high intensity infections … rather just 1-2 spores per slide for each weevil. Thus you can imagine it would be hard for a new intern to spot these little critters amongst all the other junk in a dissected bug.


Photo from my PhD work on: Nosema fumiferanae postvittana, a microsporidian pathogen in the Light Brown Apple Moth (Epiphyas postvittana)

2. After training my new undergraduate intern, and a quick lunch- I proceeded to spend about the next 4 hours (can you believe that?! 4 hours?!) building a large cage for a bunch of weevils that an amazing technician brought back from the field for me. I had to build a large cage to make sure the weevils don’t fly off these plants and start eating other water hyacinth plants that were specifically being maintained as ‘healthy/clean’ for experiments.

The goal is to mass rear ~ 8000 weevils before February among these tanks and some others that I have going right now…. fingers crossed!


Cage I built with tanks holding water hyacinth infested by the super hero weevil herbivore, Neochetina bruchi