11+ cubic meters of very clean seawater

We are also deploying two in situ filtration devices, or instruments that pump very large volumes of water through a fine filter, to collect particles directly from the water column. We are talking about ~340 liters of water pumped by each instrument during one-hour deployments. We’ve made 16 deployments so far, which make a total of 11.2 cubic meters of filtered seawater (quite a bit). The pumps are attached to a wire that lowers them to target depths; in this case we are chasing the chlorophyll maximum (the depth with the highest concentration of chlorophyll, the most abundant pigment in phytoplankton) and near the ocean floor. We can tell exactly where the chlorophyll max is using data from a fluorometer installed on the rosette. This instrument measures the specific optical response of particles when they are exposed to light of known wavelength emitted by the fluorometer; and in oceanography it is widely used for detecting chlorophyll in seawater. Why do we care about the chlorophyll max? Because particles from the phytoplankton community will allow us to get information about type of organisms present in it, as well as detect specific molecules that carry information about the origin of these particles and the environmental conditions in which they were formed. Particles collected near the ocean floor will provide information about the level of degradation and chemical transformation of settling material that was originally formed near the surface. The chemical composition of these particles captured in the water column will be compared to that of the sediments collected with the box core, to connect modern environmental conditions with those present several hundred and thousands of years ago, with the aim of unraveling the history of climate in this region of the Atlantic Basin. Simple.


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One Response to “11+ cubic meters of very clean seawater”

  1. Dorothy Kaluzny Says:

    Hi Laura,

    Thanks for the Birthday wishes! I hope everyone there is all right and doing fine. I’ve seen something about a weather disturbance off the coast of Brazil and I hope it did not affect your ship very much.
    Thanks to all of you there who are brave enough to go to sea and the Amazon to search for more data. It’s so important to learn more about the Earth. Best wishes to all.

    Dorothy

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