Eukaryotic microbes are single-celled organisms that have a true nucleus and cytoplasmic membranous organelles that distinguish them from bacterial microbes lacking a true nucleus. Eukaryotic microbes include the photosynthetic algae and protozoa that together form the Protista. My research focuses particularly on the amoeboid protists, their ecological relationship to other protists, environmental physical and biogeochemical variables, and their role in food webs, habitat abundance and diversity, and role in carbon budgets of ecosystems (that is how carbon compounds are acquired as food and the fate of the carbon during transfer up the food chain). Eukaryotic microbes are also a significant source of respiratory carbon dioxide and at higher latitudes their high densities (astronomical numbers across large geographic regions) can yield a significant amount of carbon dioxide to the atmosphere, especially if there is increased warming in the polar regions. This respiratory source, along with a larger amount from bacteria, can contribute to atmospheric build-up of carbon dioxide and enhance global warming due to the so-called greenhouse effect. In the course of my ecological research, I also contribute papers on the fine structure (electron microscopic structures) and morphology (light microscopic features) of protists, especially any new species that are identified in our samples (including c. two dozen new genera and species). Among the aquatic environments where I have worked are the Hudson River, Firth of Clyde in Scotland, coastal Berumda, and the mangrove marshes of south Florida. Amoeboid protists also harbor pathogenic or potentially pathogenic bacteria that cause human diseases, and I have collaborated with colleagues at the College of Physicians and Surgeons examining the cellular biology and fine structural evidence that explain how amoeboid protists ingest and eventually accommodate these pathogens within their cells.