The two main classes of phytoplankton are dinoflagellates and diatoms. Dinoflagellates use a whip-like tail, or flagella, to move through the water and their bodies are covered with complex shells.
Diatoms also have shells, but they are made of a different substance and their structure is rigid and made of interlocking parts. Diatoms do not rely on flagella to move through the water and instead rely on ocean currents to travel through the water. A crude but mostly accurate way of thinking about the marine food web would be as follows: Phytoplankton typically get eaten by zooplankton, which typically get eaten by small fish, which then typically get eaten by bigger fish and mammals, and so on.
It would seem like good news, therefore, that the Arctic Ocean is producing larger and larger phytoplankton blooms.
By calculating decades of data taken from satellite imagery and collected from ice-breaking ships, the Stanford researchers have found that productivity at the base level of this ocean ecosystem has increased by more than half over 20 years. All of this sounds like it could be a boon for both biodiversity and climate change mitigation.
The initial expansion of phytoplankton in the Arctic was a symptom of climate change, not a potential cure. The Arctic is warming twice as fast as the rest of the planet, and melting sea ice has provided more open water for plankton to grow in for longer amounts of time during the year. Now here comes the weirdest part. According to the researchers, sea ice loss is no longer continuing to drive the Arctic plankton boom. Twitter Facebook Pinterest Google Classroom. Informal Assessment Assess student comprehension by evaluating the accuracy of their calculations and their contributions to the class discussion.
Extending the Learning Have students research and compare the volume of air used by a human in one day to the volume of air that algae output about billion tons per year. Learning Objectives Students will: describe the ratio between different sources of ocean oxygen production perform basic calculations based on raw data collection explain the importance of a healthy ocean identify ways humans can positively influence ocean health create a product to educate others through a mass media medium.
Teaching Approach Learning-for-use. Principle 6g : Everyone is responsible for caring for the ocean. The ocean sustains life on Earth and humans must live in ways that sustain the ocean. Individual and collective actions are needed to effectively manage ocean resources for all. Resources Provided The resources are also available at the top of the page. Prior Knowledge None.
Recommended Prior Activities None. Vocabulary algae. Also called a food cycle. Media Credits The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. Writer Diana Nelson, B. Media If a media asset is downloadable, a download button appears in the corner of the media viewer.
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Calculating Population Density. View Activity. Now and Then. View Lesson. Educational Resources in Your Inbox. Educational Resources in Your Inbox Join our community of educators and receive the latest information on National Geographic's resources for you and your students. Like land plants, they take up carbon dioxide, make carbohydrates using light energy, and release oxygen. They are what is known as primary producers of the ocean—the organisms that form the base of the food chain.
Because they need light, phytoplankton live near the surface, where enough sunlight can penetrate to power photosynthesis. The thickness of this layer of the ocean—the euphotic zone—varies depending on water clarity, but is at most limited to the top to meters to feet , out of an average ocean depth of 4, meters 13, feet.
Phytoplankton comprise two very different kinds of organisms. The larger category include, single-celled algae known as protists—advanced eukaryotic cells, similar to protozoans. These forms include diatoms and are most abundant near coasts. Occasionally, these organisms form blooms—rapid population explosions—in response to changing seasons and the availability of nutrients such as nitrogen, iron, and phosphorus.
The other type of phytoplankton cells, more primitive but far more abundant than algae, is photosynthetic bacteria. These tiny cells, some only a micron across, are invisible but present in numbers of hundreds of thousands of cells per tablespoon of ocean water.
Too small to be caught in any net, these organisms were unknown until the s, when improved technology made them visible. Scientists now know these bacteria are responsible for half of the ocean's primary productivity and are the most abundant organisms in the sea.
The group also includes cyanobacteria, which are believed to be among the oldest organisms on Earth and the origin of the photosynthetic organelles in plant cells known as chloroplasts.
Phytoplankton are some of Earth's most critical organisms and so it is vital study and understand them. They generate about half the atmosphere's oxygen, as much per year as all land plants. Phytoplankton also form the base of virtually every ocean food web. In short, they make most other ocean life possible. Through photosynthesis these organisms transform inorganic carbon in the atmosphere and in seawater into organic compounds, making them an essential part of Earth's carbon cycle.
Because they take up carbon dioxide from the atmosphere, when they die they sink they carry this atmospheric carbon to the deep sea, making phytoplankton an important actor in the climate system. Phytoplankton growth is often limited by the scarcity of iron in the ocean. As a result, many people are discussing plans to fertilize large areas of the ocean with iron to promote phytoplankton blooms that would transfer more carbon from the atmosphere to the deep sea.
Phytoplankton are critical to other ocean biogeochemical cycles, as well. They take up, transform, and recycle elements needed by other organisms, and help cycle elements between species in the ocean. Photosynthetic bacteria are especially important in the nutrient-poor open ocean, where they scavenge and release scarce vitamins and other micronutrients that help sustain other marine life.
Some phytoplankton have a direct impact humans and other animals.
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