Deep Dive: Changes in Ocean Productivity
SOCCOM Project
https://www.youtube.com/watch?v=ChyHyetAMkI

Transkript (automatisch erstellt)

0:03 hi there I'm Greta Shum we're taking a dive into the southern ocean and into ocean productivity and we're diving deep by that I mean you'll learn about
0:14 profiling floats the technology we use to observe ocean biology in the southern ocean you'll learn why the southern ocean is a key player in global ocean
0:24 productivity and he'll learn how climate change is likely to affect our oceans and the creatures that call it home ready let's go life in the ocean starts
0:36 with nutrients and phytoplankton microscopic marine algae using photosynthesis these autotrophic organisms can create their own food by
0:47 converting the dissolved carbon and nutrients in the water into organic carbon this process extracts carbon out of the environment and into the organism
0:59 transforming it into something heterotrophs fish krill and bacteria which can't make their own food can eat and eventually discarded then after
1:10 being decomposed by bacteria organic matter returns to its original form dissolves nutrients and the cycle repeats did you know that our oceans
1:20 doors more carbon from the atmosphere than the terrestrial biosphere yeah so ocean biology is worth studying here's how we study it with our oceanographic
1:33 tools that scientists use to make subsurface measurements in the ocean the great part about these floats is that they're autonomous once deployed these
1:43 foots will sink to a drifting depth of a thousand meters every few days a profiling float will sink to a depth of 2,000 meters and its sensors will begin
1:53 taking measurements all floats measure temperature salinity and pressure throughout the column of water they're profiling and each profile gives
2:02 scientists a tiny snapshot of one location in the ocean as a network a fleet of profiling floats taking measurements over many years give
2:13 scientists a complete portrait of our oceans in space and time a socom profiling float is a particular kind of float that scientists are deploying in
2:22 the Southern Ocean to measure more than temperature salinity and pressure so floats are equipped with extra sensors that measure oxygen content pH and
2:33 nutrients in the Southern Ocean socome or Southern Ocean carbon and climate observations and modeling is an NSF funded project investigating the
2:44 role the Southern Ocean will play in the global climate as it changes the hold up what's so important about the Southern Ocean how does the Southern Ocean affect
2:54 global biological production well it dominates it that's Jorge Sarmiento a professor of geosciences at Princeton University and
3:03 the director of SOCOM three-quarters of the oceanic production north of the southern ocean is due to nutrients which come to the surface and go float to the
3:12 north out of the Southern Ocean there's nowhere else in the world where that happens the southern ocean provides the rest of the ocean with nutrients the
3:21 very base of the food web but how does the southern ocean do that the answer is geography with no land masses to interfere westerly winds can whip up
3:33 powerful currents around the continent of Antarctica they make laps around the southern ocean at high speeds these winds combined with the Coriolis
3:43 force to push water northward at the ocean surface a process known as Ekman transport that surface water travels north
3:53 and as a consequence draws up water from below in a wide ring circling the internet continent upon reaching the upper ocean the up wild waters split
4:03 into two tracks water that reaches the surface close to Antartica sea ice is cooled sinks along the continental shelf and is transformed into dense bottom
4:15 water water that services north of the sea ice edge is warmed and flows northward carrying with it nutrients from the deep water once these nutrients
4:25 reach the surface phytoplankton will use them to conduct photosynthesis remember that when organic matter sinks to the bottom of the ocean it rots getting
4:36 decomposed by bacteria meaning those nutrients and carbon are dissolved back into the deep water and that's why when the deep water upwells
4:45 it brings with it nutrients and carbon now let's talk about climate change how will increased heat and increased carbon change ocean productivity well one of
4:58 the things that climate change tends to do is to make the ocean more stratified vertically and that makes it harder for nutrients and things to come up to the
5:08 surface so that's a concern that we have that's because warmer average temperatures in the atmosphere warm the surface layer of the ocean increasing
5:17 the density difference with cold deep water makes it harder for those layers to mix higher temperatures will affect ocean ecosystems and may even change
5:28 where fish can live it's also difficult for scientists to know how much carbon the ocean will be able to absorb as co2 concentrations in the atmosphere
5:37 increase these are some questions that scientists are actively trying to answer looking for more information about new research into the Southern Ocean
5:47 check out so-called Princeton edu you