Recently, my colleagues and I named three new Everglades diatom species after much morphological analyses and taxonomic detective work. While the Everglades diatom community may not be as species-rich as lakes in more temperate environments, there are many species waiting to receive a proper name and publication. The reason that so many species continue to be called "species number 17" or "looks like this other species but not quite" is because there just has not been the kind of focused taxonomic research here in subtropical and tropical places in the Western hemisphere. Contrast this to the hundreds of years of research on European diatoms. The Everglades diatom community offers great opportunities for graduate students, like me, to investigate and describe new species!

Everglades periphyton with four live cells of Mastogloia calcarea at 1000x magnification

For the FIU News article, click here:
http://news.fiu.edu/2013/09/algae-researcher-names-three-new-species-in-the-everglades/66963

For additional pictures of the new species, see below:
All scanning electron micrographs are credited to Dr. Bart Van de Vijver. Solid lines on the images indicate 10 micrometers (0.01 millimeters).

Mastogloia calcarea - light micrographs of a single specimen at two different focus levels and scanning electron micrographs of two specimens showing the exterior and interior of the cell. This diatom is the most dominant species in Everglades periphyton. It has long been mistaken for Mastogloia smithii or M. smithii var. lacustris because original material for these two taxa were not accessible for accurate comparison with the Everglades taxon.

Mastogloia pseudosmithii - light micrographs of a single specimen at two different focus levels and scanning electron micrographs of two specimens showing the exterior and interior of the cell. This diatom is similar to Mastogloia smithii because of its elliptical shape but has completely different patterning on the exterior and has completely different internal ultrastructure.

Envekadea metzeltinii - light micrographs and scanning electron micrographs of four specimens showing different sizes and the exterior and interior of the cell. This diatom is part of a recently erected genus identified by the sigmoid shape of the raphe (slit that goes through the center) and the irregularly shaped areolae (holes on the cell surface).

What is algae?

This seems like a very simple and easy to answer question. Surprisingly though, many people (even those doing research on specific groups of algae like me), have a tough time answering this question. Mainly, I think this is because we rarely get this question from other people (scientists or laypeople). Also, since science often encourages you to focus your research questions, we rarely have to even think about how a specific group of algae is related to other groups of algae, or how algae fits into the evolutionary scheme of other living organisms (are algae plants or animals?...).



Anabaena, a common genus of cyanobacteria (aka "blue-green algae").

Previously, I blogged about diatoms that live in periphyton in the Everglades, and what I do to periphyton to remove all the other algae that obscure the diatoms I want to study. So far, I haven't explained what algae is at all, and only explained that diatoms are a special group of algae with cell walls made of glass. This summer, I took a Freshwater Algae course at Iowa Lakeside Lab and filled in the gaps of my knowledge about non-diatom algae.

So without further ado, here is the definition of algae:
1. They must have a primarily aquatic life.
2. They must have chlorophyll a and the ability to perform photosynthesis.
3. They must have (relatively) simple reproduction.

That's it.

Now here is the longer version of the answer. Algae is an unnatural group, meaning they do not form a single evolutionary lineage, in which they are related to a common ancestor. Algae includes both prokaryotic cyanobacteria (i.e., blue-green algae) and eukaryotic protists (which are neither plants nor animals!).

Without algae, there would not be life on Earth as we know it. It was because of the photosynthetic activity of cyanobacteria four billion years ago that the Earth's atmosphere built up enough oxygen for aerobic organisms to evolve. Cyanobacteria were the first organisms to contain chlorophyll a, among other pigments, which absorbs sunlight to produce energy, and release oxygen as a waste product.

Graham et al. 2006 Plant Biology

Then, about two billion years ago, a heterotrophic eukaryote swallowed a cyanobacteria and instead of digesting it, obtained a new organelle: the chloroplast. This event is called endosymbiosis, and the evidence is found in the double membrane around the chloroplast in green and red algae. The chloroplast gave the eukaryote the ability to produce its own energy via photosynthesis.



Endosymbiosis: how a eukaryotic cell obtained a chloroplast and the ability to perform photosynthesis

Among the eukaryotes, there are many groups that are considered algae. Actually, the endosymbiotic event happened more than once (secondary and tertiary endosymbiosis) by swallowing up either a green algae, red algae, or even a diatom. That means some algae have three (euglenas, dinoflagellates), four (diatoms, chrysophytes, cryptophytes, brown algae, etc.), or even five (some dinoflagellates) chloroplast membranes!! Some algae can live without sunlight as heterotrophs. Some algae have flagella. Some have cell walls made of glass, rather than cellulose. Some have additional pigments like carotenoids or phycobilins to give them a more orange or brown or reddish color. Accessory pigments help algae absorb light at additional wavelengths to do photosynthesis in dimmer light (such as in deeper depths underwater) and also provides photoprotection in excess light conditions (such as in the intense sunlight of south Florida).



Graham et al. 2006 Plant Biology

Green algae with flagella from left to right: Pandorina, Lepocinclis, and Euglena.

Filamentous green algae from left to right: Mougeotia, Stigeoclonium, and Hydrodictyon.

Diatoms from left to right: a single cell Craticula, a stellate colony of Asterionella, and tube colony of Encyonema.

Both cyanobacteria and eukaryotic algae exhibit an astounding level of diversity in morphology, function, and life history. A conservative estimate of the number of extant species is over a million. Some can produce large blooms with dangerous toxins, which has resulted in bad PR for algae. But algae are beneficial to humans in many ways. To name only a few, algae can be used to remove excess nutrients from wastewater, used to make food products (what is sushi without the red algae used to make nori?), used in the production of antibiotic and anti-cancer pharmaceuticals, and are being used in the development of biofuels. Algae provide food for higher trophic levels like invertebrates that are eaten by small fish, which are in turn eaten by bigger fish.

Algae are important research and environmental monitoring tools. The glass cell walls of diatoms leave permanent records in sediments that paleolimnologists use to understand long-term climate and land use patterns. Algae also play an important role in taking up carbon dioxide from the atmosphere and carrying it down into the depths of the oceans. As sea surface temperatures rise, there is less mixing of the water column, which means less nutrients for algae, and fewer algal cells (especially larger and heavier algae) to sequester carbon dioxide from the atmosphere. Because algae are first responders to environmental change, we really need to learn more about them and pay attention to what they indicate about the future.


If nothing else, there is one reason why we should all be thankful for algae every day: every second breath you take is because of ALGAE.

My research is on the diatom communities of the Everglades. To study how the communities respond to environmental changes, I have to identify and count each of the diatom species I encounter under the microscope. To do that though, the diatoms have to be stripped clean of any organic material and other 'junk' in the sample. The diatoms go through a harsh bath of acid and heat, until all that is left of them are their empty but beautiful cell walls. This is possible because diatom cell walls are essentially glass.

Beakers of diatom samples mixed with hydrogen peroxide and nitric acid boiling away on a hot plate. Different amounts of organic matter (like peat or plants) and inorganic matter (like sand or clay) result in different colors and reactions.

In the Everglades, the limestone bedrock adds a lot of calcium carbonate into the soil and periphyton. Some components of periphyton (especially mucilage-producing filamentous algae) attract calcite crystals like a magnet. The addition of calcium carbonate, an inorganic substance, makes Everglades periphyton a bit more difficult to process all the junk away. That's because inorganic things don't really dissolve with the normal chemicals we use to get rid of organic stuff. But we don't want to try to dissolve too much of the inorganic material either, because we don't want to damage the diatom cells! Everglades samples go through an intense process including sulfuric acid, potassium permanganate, and oxalic acid. Check out this animation that shows how Everglades periphyton is transformed into a bubbly and acidic concoction, then into a white powdery layer of clean diatom cells at the bottom of the beaker:




Here are some before and after processing images of periphyton and diatoms under the microscope:

I would like to introduce you to a new rising star in the FCE, Sara Osorio! She has been working with FCE LTER Education and Outreach coordinator, Mr. Nick Oehm, and our lead PI, Dr. Evelyn Gaiser. Her research project is about the diatoms found in the wetland restoration area of the Deering Estate (Biscayne Coastal Wetlands Project).

Sara Osorio, FCE LTER High School Researcher at the FIU Periphyton Lab

Sara is currently a junior in high school. She became involved in FCE research because she was always fond of her science classes, including AP Biology. Through the recommendations of Mr. Oehm, Sara became one of our newest high school researchers.

Sara is working with Dr. Gaiser in the Periphyton Lab at FIU as a LTER high school research assistant, where she is receiving personal instruction on all the necessary aspects of a real scientific research study: field sampling, laboratory procedures, diatom identification, and microscopy. Later, there will likely be data analysis, poster making, and writing advice, too!

Through collaboration with the Deering Estate, Sara and Dr. Gaiser made a trek through the coastal wetland restoration area to collect periphyton samples across a fresh water to marine water transect. This area used to be the location of a mansion, as well as a Native American burial ground, now being rehabilitated to its natural state. Sara enjoyed the field sampling experience, as she has always loved to be out in nature, even though it required her to get a bit down and dirty (she made sure to wear old jeans that day). One part of the transect was full of hairy, slimey, filamentous algae - but even that could not stop Sara.

Sara sampling hairy, slimey, filamentous algae at the Deering Estate

Sara sampling with Chris Sanchez, FCE and CAP LTER undergraduate researcher

Sara learned how to process these samples in the lab. She remembers how cool it was to see the bubbling and foaming reaction of periphyton when you pour acid on them - a necessary step in cleaning samples for diatom identification.

Currently, Sara is learning to become an expert in microscopy and diatom identification. She says this step has been the most challenging part of her research experience so far because there are so many details on a diatom cell that you need to look at for identification. However, she thinks it is very cool to see things under the microscope that not many people get to see.

Pleurosigma, diatom identified and photographed by Sara

In the future, Sara aspires to continue her studies in biology. She is also keeping her options open for opportunities in the medical field, especially through the military services. Sara expresses her gratitude for the opportunities she has found through FCE, especially the personal guidance by a professor. She is a great example of how future scientists can get an amazing head start through scientific education and outreach programs. Not to mention, the Periphyton Lab is thrilled to have such a bright and motivated student working with us!

Sara sampling coastal periphyton with Dr. Evelyn Gaiser

Graduate students and PIs: There are amazing young scientists like Sara who are willing to work in your lab for free! Be sure to contact Nick Oehm if you are interested in having your own rising star.

High school and undergraduate students: Research experience is rare and looks extremely impressive on any college or graduate school application. Not only do you learn a lot, you also enter into a network consisting of your mentor and their colleagues. Their word of recommendation means a lot! Don't miss these opportunities!