Welcome to BIO121/ESS120: Introduction to Environmental and Ecological Microbiology at UC Merced! This page provides additional online content associated with the course, including short video lectures by Professor Beman, additional videos and interactives, and additional reading materials.
Marine Microbiology
The ocean is the ultimate microbial habitat from top to bottom. As you will learn, this has multiple implications for the ocean and the entire planet—from the abundance and diversity of microbes, to how they function, to how this affects entire food webs (including the large marine animals that we know and love).
7.1 Intro to the Ocean. This video lecture provides a quick introduction to the variations that we see in the ocean, especially with depth. When we study the ocean, always remember that what we see from the coast is just a tiny sliver of the ocean! It is very wide and very deep, and mostly empty of large organisms (but not microbes).
As always, pause, rewind, rewatch, and take notes!
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7.2 Dominant Marine Microbes. This video lecture covers the three dominant microbial groups that we see in the ocean: Prochlorococcus, SAR11, and the marine Thaumarchaeota.
Most ecological communities are dominated by a few species, with many rare ones. Microbial communities tend to be even more ‘uneven’ (but have lots and lots of species), and marine microbial communities are especially uneven (we will learn more about this aspect of microbial diversity). The three groups that you will learn about usually make up 25%-60% of all the microbial cells in the ocean (depending on depth and location). Because the oceans are so voluminous, and there are 1 million cells per milliliter of seawater, these are the dominant organisms on Earth! But you probably haven’t really heard of them until now…
As always, pause, rewind, rewatch, and take notes!
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7.3 Phytoplankton. We just learned about one key phytoplankton group and several other dominant groups of marine microbes. This article gives a general overview of phytoplankton and their importance. It is sometimes hard to believe, but phytoplankton support essentially all of the amazing creatures that we see in the ocean. This NASA article covers this and sets up our thinking about different regions of the ocean. Please read the entire article:
https://earthobservatory.nasa.gov/features/Phytoplankton
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7.4 Ocean Circulation. We just learned about some of the vertical differences that we see in the ocean. But if you’ve been to the ocean—and especially on a boat—you know that the ocean is a fluid in constant motion. While waves and tides are clearly important along the coast, ocean currents are most important at the large scales of entire ocean basins. This page from the Smithsonian provides an introduction to ocean currents. You can also read about waves and tides if you are interested and want to, but please read the first ~25-33% of this up to the section titled ‘Deep Currents.’
Please also watch the video on the Coriolis Effect. If you haven’t heard of this before, it is pretty interesting as it affects how air and water appear to curve and spin on the surface of the Earth. (This includes the idea that toilets in the Southern Hemisphere swirl in the opposite direction, which isn’t exactly correct, but the general idea is true!)
https://ocean.si.edu/planet-ocean/tides-currents/currents-waves-and-tides
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7.5 Ocean Circulation and Nutrients. We sometimes don’t realize that different areas of the ocean can be quite different from one another. To us, it sometimes all looks the same, especially over the spatial scales we are used to. For example, even from northern to southern California, the ocean doesn’t appear that different. However, if you compare California to tropical islands, it does seem quite different!
In this video lecture, we will see how ocean circulation drives these differences, especially through the availability of nutrients to phytoplankton. Because phytoplankton are the base of most of the ocean food web, this affects everything else in the ocean…
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7.6 “Forests,” “Grasslands,” and “Deserts” of the sea. Following up on the last video lecture… in this one we will see how the differences in ocean circulation affect which phytoplankton are found where. This affects entire food webs, as well as other aspect of ocean ecology, biology, and biogeochemistry.
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7.7 Marine Microbes. This is a very good article on marine microbes that starts at a very basic level and then provides much more detail. It covers all the interesting things that marine microbes do. It is also fairly long, so you may want to read it in chunks. View it more as a chapter in a book than a webpage, or else your brain will shut off!
Please also watch the short videos on ‘The Microbial Loop’ and ‘A Microbial World.’ You can skip the video on symbiosis, as we will come back to this (but it is interesting). :
Beman Lab, University of California, Merced 