Emily Spiegel, Bryn Mawr College
One intern’s perspective on lab work, South Carolina, and the coolest organisms in and out of water: phytoplankton.
The lab itself is large, packed to bursting with equipment, boxes, cabinets, monitors, and glassware. An antechamber acts as a sterile room for the most delicate of procedures, demanding precision and care. Many things reside in this room, but never quiet. The constant whirling of a machine’s fan, the hum of a freezer housing samples from a time beyond easy recollection, the typing of a research assistant hunched over innumerable data sheets…all these and more cut through the quiet throughout all hours of the day and night.
And at the heart of it all is the algae.
Small, marine microorganisms constituting a larger class known as phytoplankton, algae are the unsung heros of the environmental world. Energy, or the basic ability to do work, is the key to survival, growth, and reproduction. Without it you (and your genes) aren’t going anywhere. Algae harness the energy readily available from sunlight and convert it into a useable currency in a process known as primary production. This energy is then distributed to the many higher animals that eat them. They are the foundation of the marine food web and of the world’s energy supply, contributing to 45% of the planet’s primary production (Brierley 2017). In short, algae are cool.
So cool in fact, I’ve decided to spend my entire summer studying them. More specifically, I’ll be studying patterns of their reproduction and growth. A grad student running an experiment in this lab last year got unexpected results when she raised algae in 24 hours of continuous light instead of the normal 12 hours of light:12 hours of darkness she had followed previously. Despite a limitation in the nitrogen added to these samples, which typically inhibits growth, the populations grown in 24 hours of light were able to grow successfully. So researchers went looking for answers.
One potential explanation is that the continuous light conditions caused the induction of sexual reproduction in the algae samples. Algae, like the rest of us, don’t like to be stressed. And being constantly exposed to light, which they automatically begin to utilize for primary production, is very stressful. It’s kind of like giving a kid a bunch of candy bars. A little is nice, a lot induces a sugar high and headaches for anyone within a 20m radius. The algae have too much energy and so they start to adjust their behavior to accommodate for the stressful conditions. One accommodation is sex. That’s right, stress out your algae and they might just turn on the Marvin Gaye and set the mood. Normally the species I’m studying (Fragilariopsis cylindrus, or just Frag for anyone without a PhD) reproduces asexually allowing high growth rates within the population. My lab is also curious as to whether low light conditions (a cycle of 6 hours of light and 18 hours of darkness) might be equally stressful to the algae and cause a similar response.
This is where I come in. This summer I’ll be exposing algae to conditions of varying light and nutrient stress in order to determine if stress actually does cause them to start reproducing sexually. Along the way, we’ll keep track of growth rates by measuring biomass, or the amount of live material within a sample. This can be measured by a variety of cool devices which tell me the number of cells in a particular volume of sample and the amount of chlorophyll being utilized in that sample. Chlorophyll is a component of the cycle of photosynthesis and is therefore a measure of the primary producers (i.e. the algae) in the sample. Eventually I’ll also run genetic analyses, tracking the utilization of genes involved in sexual reproduction as a way to determine if the algae are reproducing sexually instead of asexually.
All in all, it’s bound to be an interesting summer. Full of days at the beach, early mornings with a culture counter, and lots and lots of algae.
I’d like to acknowledge the entire DiTullio/Lee lab at the National Oceanographic and Atmospheric Administration as well as the National Science Foundation’s Research Experiences for Undergraduates program organized by the College of Charleston Grice Marine Laboratory. This project would not be possible without the support and guidance from these institutions and individuals.
Brierley, Andrew. “Plankton.” Current Biology Magazine 27 (2017): 478-83.