In 2011, the Friday Harbor Laboratories purchased a JEOL Neoscope, a modern benchtop scanning electron microscope (SEM), for use in teaching and research. Here are three samples of work in my laboratory that make use of the Neoscope.
1. Dinoflagellate blooms
Dinophysis cells from the phytoplankton around the Friday Harbor Laboratories, August 2011, viewed with SEM.
Dinoflagellate algae are common components of naturally-occurring blooms in marine waters, especially in the summer months. Some of the dinoflagellates can be harmful to humans. For example, species of Dinophysis
are responsible for the human ailment called “diarrhetic shellfish poisoning”.
In the summer of 2011, there were blooms of a dinoflagellate alga, assigned to the species Gonyaulax spinifera, that occurred from northern California to at least the Salish Sea region of northern Washington. While the alga in the region of the San Juan Islands was not associated with bioluminescence and did not appear to have any adverse impacts on marine life, the alga in Sonoma and Marin Counties, California, was associated with strong bioluminescence and with massive dieoffs of abalone and other marine invertebrates in shallow coastal waters. Same alga or different?
Gonyaulax spinifera from Eastsound, Orcas Island, Washington, viewed with SEM
Single cell of the Gonyaulax spinifera bloom from Eastsound, Orcas Island, Washington
Single cell of Gonyaulax from the Sonoma County bloom, August 2011, viewed with SEM
The San Juan Island population differs from the Sonoma population in the SEM: the ridges on the cell covering (thecal plates) are more pronounced, and the pores in the plates are smaller. DNA analysis of the San Juan Island bloom tells us that these algae are genetically distinct from all other populations of algae called G. spinifera
that have been studied. Analysis of the Sonoma population is underway.
This work is being funded by California Sea Grant.
2. Amoebae that eat algae
Light micrographs of several strains of Paramoeba, among the more common amoebae that eat algae.
Little is known about the protozoa that eat algae in ocean waters, yet these microorganisms can grow rapidly and wipe out both natural and farmed algal populations. We are investigating the taxonomy, species diversity, growth rates, and feeding choices of amoebae from both local and tropical marine waters.
Two amoebae (genus Paramoeba, strain B6 in picture above) viewed with SEM. The surface coat of scales is characteristic of the genus; the scales cannot be seen with light microscopy.
The SEM provides views of the cells in three dimensions that are difficult to capture using light microscopy. Also, cells of amoebae in the genus Paramoeba
have tiny scales on their surfaces. These scales are probably made of complex polysaccharides, and they are too small to be seen with the light microscope. Minute differences in the structure of these scales (not shown here) permit experts to distinguish among the species of Paramoeba
Parts of this work were funded by the algal bioproducts company Cellana LLC.
3. Algae that burrow into calcium carbonate
Rocks made primarily of calcium carbonate (limestone) are abundant on Earth.
Two species of the carbonate-boring green algal genus Ostreobium, viewed in cast preparations under SEM. The species on the left is from Hawai`i, the one on the right is from the San Juan Island area. Both were previously considered to belong to a single species.
Biotic reefs, built by coral animals and coralline algae, are a well-known example. Shells of many animals such as clams, mussels, and barnacles also contain large amounts of calcium carbonate. Chemical processes will “weather” carbonate rocks, in both air and water, and in the process produce free carbon dioxide, which gets added to the biosphere. There are, however, also large communities of algae, bacteria, fungi, protozoa, and invertebrate animals that burrow into carbonate rocks and tend to hasten their dissolution.
We are engaged in a study to determine the biodiversity of these carbonate-boring algae, place key strains into culture, and make these strains available for research on growth and carbonate-dissolution rates of individual species under a range of laboratory-controlled conditions.
Two species of the carbonate-boring green algal genus Phaeophila, viewed in cast preparations under SEM. The species on the left is from Massachusetts, the one on the right from Hawai`i. Both were formerly considered to belong to a single species.
Our work to date tells us that the species diversity is at least tenfold greater than previously recognized, and that species once thought to be globally distributed actually have more localized distribution, most commonly into “temperate/boreal” and “tropical” species.
I, and several other scientists and educators at FHL, use the Neoscope to teach high school, undergraduate, and graduate students the biodiversity of algae and other marine organisms. The instrument also gets used in studies and course exercises in biomechanics and in marine ecology. The Neoscope is robust and simple to use, and is therefore well suited for use in the teaching laboratory.