Archive for the ‘Oceanography’ Category

Mapping the Bottom of the Seas

Wednesday, August 26th, 2015

We are a map loving species – from our local streets and highways to the whole universe. Now we have a new map of the bottom of the world’s oceans, and it is wonderful.

It is digitized, built from 14,400 data points pulled from data gathered by research cruises over the past half century and now converted to a continuous map by Big Data experts at the University of Sydney. Thirteen types of bottom sediments are color coded, and the whole globe is there on your screen to rotate in any direction and explore.

Take it for a spin: it is irresistible.

One view of the digitized seafloor (geologyin.com)

One view of the digitized seafloor (geologyin.com)

Seafloor sediments distinguished by source and nature of particles, and are coded by color (geologyin.com)

Seafloor sediments distinguished by source and nature of particles, and are coded by color (geologyin.com)

Published in the current issue of Geology, this is really the first new view of the ocean floor in 40 years, and not surprisingly, it is full of surprises.

First, it is a much more complex patchwork of the microfossil remains of diatoms, radiolarians, sponge spicules, shell and coral fragments, along with sand, silt, clay, mud and vulcaniclastics than all previous maps had led us to expect.

Radiolarian ooze is made up of the skeletons of protistan radiolarians which are microscopic single celled animals that secrete silicon skeletons and feed with pseudopods that stick out through the holes in skeleton (micro.magnet.fsu.edu)

Radiolarian ooze is made up of the skeletons of protistan radiolarians which are microscopic single celled animals that secrete silicon skeletons and feed with pseudopods that stick out through the holes in skeleton (micro.magnet.fsu.edu)

And then, also unexpected, surface productivity of phytoplankton diatoms (a major carbon source) is not reflected by the abundance of seafloor abundance of diatom ooze (a carbon sink) – we understand less than we thought we did.

Diatom ooze is made up of the silicon skeletons of phytoplankton diatoms, each species with its own unique architecture, which are so abundant in the  surface waters (ucmp.berekely.edu)

Diatom ooze is made up of the silicon skeletons of phytoplankton diatoms, each species with its own unique architecture, which are so abundant in the surface waters (ucmp.berekely.edu)

Calcareous ooze contains the calcareous skeletons of other single celled protistans like coccolithophores (serc .carleton.edu)

Calcareous ooze contains the calcareous skeletons of other single celled protistans like coccolithophores (serc .carleton.edu)

The chalky cliffs of Dover were once coccolithophore sediments (wordsinmocean.com)

The chalky cliffs of Dover were once coccolithophore sediments (wordsinmocean.com)

In fact, at stake is our much broader understanding of the deep ocean’s response to climate change. We need to understand the global geochemical cycles, the behavior of deep-water currents, and the transport of ocean sediments, and this map provides a framework for asking – and answering – more detailed questions.

What we see now is a more complicated, less predictable picture of the global seafloor. If we understand why sediments on the seafloor are where they are, we have another window into reconstructing the past environments of our planet, a valuable key to understanding what is now occurring.

Perhaps most of all, we are reminded once again by a new and global map like this new one that in our local piece of our galaxy our planet is a small, isolated biological and physical oasis where change in any one component may radically influence all the others in ways we can increasingly monitor and struggle to understand, with a history we can increasingly explore.

And of course with a near-future that is so uncertain yet we must still plan for.

This map can only help.