Learn how the remains of tiny living organisms help scientists see the big picture.
Microscopic biological proxies are tiny plant and animal remains, like pollen and foraminifera (single-celled marine zooplankton), that are preserved in geological archives like sediment and ice cores. Because the distribution of these organisms is controlled by temperature, moisture availability, and other environmental factors, their presence in a sample allows scientists to make inferences about the environmental conditions when the sample was deposited. When scientists interpret microscopic proxies alongside other types of data, like elemental ratios, stable isotopes, and sediment grain size, they can piece together a more complete picture of past climate and environmental conditions.
Examples of micro-proxies include:
- Foraminifera: single-celled marine zooplankton with calcium carbonate shells
- Ostracodes: tiny crustaceans, sometimes called “seed shrimp,” that build calcified shells
- Pollen from plants and trees
- Diatoms: marine and freshwater algae with shells made of silica
- Calcareous nannofossils: single-celled marine phytoplankton with calcium carbonate shells
- Dinoflagellates: marine plankton that form organic cysts and cause “red tides”
Plant macrofossils: identifiable fragments of moss, grasses, and seeds
Some proxies record temperature, while others reflect salinity, ice cover, productivity, river input, or circulation. By examining multiple proxies from a single sample, like a sediment core, we can piece together the environmental history of a site, with each proxy adding a unique line of evidence to strengthen and clarify the overall story.
When multiple proxies independently point to the same change, like warming water or reduced sea ice, confidence increases because different parts of the system are telling a consistent story. Meanwhile, conflicting proxy results can be a clue to complexity in the system, like seasonal effects, changing water masses, or ecological thresholds.
Explore this cartoon series to learn more about micro proxies!
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Learn more about different types of paleoclimate proxies>>
Learn how the remains of tiny living organisms help scientists see the big picture.
Microscopic biological proxies are tiny plant and animal remains, like pollen and foraminifera (single-celled marine zooplankton), that are preserved in geological archives like sediment and ice cores. Because the distribution of these organisms is controlled by temperature, moisture availability, and other environmental factors, their presence in a sample allows scientists to make inferences about the environmental conditions when the sample was deposited. When scientists interpret microscopic proxies alongside other types of data, like elemental ratios, stable isotopes, and sediment grain size, they can piece together a more complete picture of past climate and environmental conditions.
Examples of micro-proxies include:
- Foraminifera: single-celled marine zooplankton with calcium carbonate shells
- Ostracodes: tiny crustaceans, sometimes called “seed shrimp,” that build calcified shells
- Pollen from plants and trees
- Diatoms: marine and freshwater algae with shells made of silica
- Calcareous nannofossils: single-celled marine phytoplankton with calcium carbonate shells
- Dinoflagellates: marine plankton that form organic cysts and cause “red tides”
Plant macrofossils: identifiable fragments of moss, grasses, and seeds
Some proxies record temperature, while others reflect salinity, ice cover, productivity, river input, or circulation. By examining multiple proxies from a single sample, like a sediment core, we can piece together the environmental history of a site, with each proxy adding a unique line of evidence to strengthen and clarify the overall story.
When multiple proxies independently point to the same change, like warming water or reduced sea ice, confidence increases because different parts of the system are telling a consistent story. Meanwhile, conflicting proxy results can be a clue to complexity in the system, like seasonal effects, changing water masses, or ecological thresholds.
Explore this cartoon series to learn more about micro proxies!
Learn More
Learn more about different types of paleoclimate proxies>>