Mapping the Uncharted Diversity of Arctic Marine Microbes

Background Information

January 2015 - August 2016
Eric Collins and Sarah Hardy, Expedition Principal Investigators, University of Alaska Fairbanks

The Arctic Ocean is home to an extraordinary diversity of life, including the unseen majority: microbes. Algae, heterotrophic protists, bacteria, archaea, and viruses all live together in a hidden ecosystem that recycles nutrients within Arctic seawater, sediment, and sea ice. These tiny organisms play a critical role in the overall Arctic ecosystem, making possible the amazing bounty of macroscopic life found there.

Despite the vastness of sea ice cover in the Arctic, the molecular diversity in polar sea ice habitats is almost completely uncharacterized. The Arctic is one of the most rapidly changing environments on Earth, and without a baseline understanding of the microbial organisms that are key in structuring the overall function of Arctic ecosystems, we cannot adequately prepare for future changes and make informed decisions about resource use in the region.

Using several hundred samples previously collected from around the Arctic, this project aims to establish a necessary baseline of microbiological community data by applying next-generation DNA sequencing technologies and cutting-edge bioinformatics approaches. We refer to this strategy as ‘metagenomic mapping’ and argue that more detailed metagenomic maps will lead to many future discoveries.  

The essays below will help you to understand the goals and objectives of the mission and provide additional context and information about the places being explored and the science, tools, and technologies being used.

  • Mission Plan

    Single-celled (unicellular) algae, which develop in the lowermost sections of sea ice, often forming chains and filaments. Ice algae are an important component of the Arctic marine food web.

    The Arctic Ocean is home to an extraordinary diversity of life, including the unseen majority: microbes. Algae, heterotrophic protists, bacteria, archaea, and viruses all live together in a hidden ecosystem that recycles nutrients within Arctic seawater, sediment, and sea ice, making possible the amazing bounty of macroscopic life found there.

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  • Reading the Books of Life in the Arctic Ocean

    Here we explain the cutting-edge ‘metagenomics’ methods used by scientists to explore this hidden microbial realm.

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  • Linnean Classification

    Life on Earth is extraordinarily diverse, with millions of creatures that are large, small, simple, complex, round, flat, dangerous, or cute. But how do scientists catalog this diversity? We can probably all recognize that grouping organisms into categories like “cute” or “ugly” may not be the most objective or useful, but what does make a good system of classification?

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  • DNA Classification

    All of life on Earth is divided into three major domains: the Bacteria, Archaea and Eukarya. This is the universal phylogenetic tree based on a gene that we all have, the ribosomal RNA. We (humans) are located in the crown group of animals, but the majority of diversity on this planet is in the microbial (bacterial and archaeal) world.

    About 50 years ago, two scientists – Linus Pauling and Emile Zuckerkandl – pioneered a new way to categorize life, which has since revolutionized our understanding of how life on Earth is connected.

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  • Invisible Life in Arctic Mud

    Bristle worm collected from seafloor mud with a box core during a 2002 Arctic ocean exploration mission.

    The muddy seafloor comprises the largest habitat on Earth, ranging from shallow continental shelf to the abyssal seafloor thousands of meters deep.  Seafloor sediments support an enormous diversity of life.  Some fishes and larger invertebrates, such as sea cucumbers and urchins, can be found living on, or just above, the sediment surface.  However, the vast majority of organisms live within the sediments themselves.

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  • Sea Ice

    Sea ice extent in the Arctic.

    Sea ice is a thin sheet of frozen seawater covering the ocean at high latitudes, with an average thickness of about 6 feet (2 meters) and a maximum thickness of about 30 feet (10 meters).

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