Last autumn I went on vacation with my brother to sunny Italy. Along with marvelling at St. Peter’s Basilica and eating great food, I did what any other keen museum volunteer would do: collect Italian freshwater diatoms for the museum’s collection.
Diatoms are fascinating, microscopic, one-celled algae, with a thin silica shell, measuring just five to 150 microns, or millionths of a meter.
These free-floating phytoplankton are the foundation of the aquatic food web, converting sunshine into stored chemical energy, and carbon dioxide into oxygen. Diatoms are found in all fresh and marine waters. Biologists use them for water quality analysis and climate change research.
Whenever I had free time during the trip, I collected various types of diatom samples, amassing a total of 41 from lakes, rivers, fountains and ponds across Italy, including Rome, Florence, Venice, and Sicily.
Back at the lab in the museum’s collections facility, samples were processed, and specimens photographed and identified using an online Italian government diatom guide. Interestingly, the diatoms reveal a lot about Italian water quality and terrain at the sampled sites.
For example, most diatoms at sample sites indicate a preference for alkaline pH reflective of the limestone, volcanic and carbonate rocks that make up most of the Italian Peninsula. Some species are indicators of water with moderate to high levels of organic nutrients, likely from nearby farms. Lastly, some specimens indicate traces of brackish water, perhaps due to salt in the Italian soil or proximity to the Mediterranean Sea.
The trip yielded many of the same species of diatoms I’ve collected in Canada, Ireland and the Middle East.
For museum diatom researchers and students these new Italian specimens are proof that some scientific souvenirs can provide a lot more than just good memories!