Extra Credit: Eric Collins

Major Points:

Eric Collins presented a seminar on some of the specific aspects of oceanography that he studies: the flow of water and ice through the Arctic Ocean and how the structure of life in the Arctic Ocean is affected by the different characteristics of this flow. He noted that the presence of ice in sea water affects the chemical composition of the water. As ice freezes, it releases salts into the water, which then play a role in forming layers within the Arctic seawater possessing different gradients of both salinity and temperature; a side effect of this process is that water currents which circulate through the arctic emerge both colder and fresher than before as they now contain sea ice. Changes in the salinity of seawater as well as the formation of different gradients of salinity and temperature in the ocean are all aspects which impact microbe survivability and the ways in which microbes interact with each other and their environment. He also mentioned that the input of freshwater into the arctic from multiple ocean currents, while not a significant volume compared to that of the total volume of water which regularly circulates through the Arctic, plays an important role in the microbiological structure of the Arctic Ocean.

Relation to Microbiology and Questions:

Currently, much of the sea ice in the arctic is very young: less than 10 years old. The melting of arctic ice changes the composition of the ice and water in the Arctic, allows light to reach further into the sea water, precipitates an earlier spring in the region, contributes to an increased abundance of plankton, and results in less ice for animals, such as polar bears, to live on. These changes also affect the habitats in which microbes in this region live. Microbe content in water and ice differs geographically as well as between the different layers of water and different types of ice found in the Arctic. There are differences between microbes found in sea water, young sea ice, and old sea ice; such differences indicate that loss of or changes to the composition and abundance of these habitats would likely result in extinction for those microbes which require the specific conditions provided by each type of environment. Definite biogeography and special patterns also exist in terms of microbe presence in the water currents and sources which contribute to water flow through the Arctic Ocean.

Some questions which this lecture brought to mind are: can the various species of microbes found in the Arctic Ocean all be traced back to the incoming currents? Are there some microbes which are only found in the Arctic Ocean? Eric Collins also mentions how different microbes are found within the different temperature and salinity layers within Arctic seawater as well as in old and young sea ice in the Arctic regions. Does this differentiation based upon salinity and temperature also apply to the many viruses which live in the ocean? I am very curious about this last question in particular after learning in lecture that there are so many viruses in the ocean!

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