Posted by: Alison Cawood | August 7, 2009

SEAPLEX Day 6

Today we have a blog written by Jesse Powell, a graduate student at Scripps Institution of Oceanography.

Jesse writes:

Hi. My name is Jesse Powell and I am a Ph.D. student starting my fourth year at Scripps Institution of Oceanography. I study zooplankton and the effects that oceanic currents and fronts have on zooplankton populations. Most of my work takes place in the California Current near Point Conception just north of Santa Barbara, so traveling way out here to the Gyre is a new experience for me. Working on and in the ocean for many years now, I have grown accustomed to thinking in large scales, but this trip has broadened my perspective yet again.

Let me try to explain how absolutely enormous the ocean is. First of all, just to get to our sampling location in the gyre we will have traveled for almost five days continuously. We’ve had perfect weather, with very little swell, so when you look out from the bridge of the ship you see for six miles in all directions nothing but a featureless blue plain and wide open sky. If we had the ability to walk on water and we needed to walk back to our starting location from our current location, then we would need to walk 20 miles each day across this vast blue plain for over a month. On a percentage basis, the ocean constitutes much more than 99% of the above-ground habitable volume on earth. For example, if you consider just the water volume under the keel along our planned cruise track in a strip 500 meters to either side of the ship, then that water volume would be enough to cover the continental United States to a depth of about 1 meter. And yet this tiny strip of planned cruise track covers only about 0.003% of the Pacific Ocean. The ocean is truly, truly enormous, which is one reason studying it is such a challenge.

Another challenge is that the ocean is variable at many different space and time scales. Water properties like temperature and salinity change dramatically in the vertical direction, but sometimes very little in the horizontal direction. For example, water temperature may drop from a balmy 21°C at the surface to a bone-chilling 8°C  only a few hundred meters below the surface, while in the horizontal direction the sea surface temperature has barely changed more than a degree for the last 500 miles. These properties are variable not only over different spatial scales, but also over days, weeks, months, years, decades and longer time periods as well. And the biology of the ocean is even more variable than the physics. Locations that have dense aggregations of zooplankton (krill, for example) at one time of day, may be devoid of most zooplankton at another time. As oceanographers, one of our key challenges is to describe and measure the scales of variability, both in time and space, of key physical, chemical and biological properties of the ocean.

So, the ocean is enormous, variable and challenging to study. Why study it? Well, for one thing, it is intellectually exciting, the vistas are terrific and the people are fun! Another reason is that understanding how the ocean works is fundamentally important to the welfare of humanity and our planet in general. The ocean provides us with food, oxygen and our climate. We could not live on this planet without healthy oceans. Believe it or not, it was once believed that the ocean was so vast that puny humans couldn’t possibly affect it. Global warming, ocean acidification, overfishing and pollution have proven this thinking to be untrue.

During the last day or so, as we’ve started to enter the gyre, we have begun to see more and more plastic debris floating in the water as we steam along at 10 knots (11.5 miles per hour). Yesterday, our bird and whale observers counted hundred of floating plastic pieces during the day. Only a sustained scientific survey lasting many months would be able to quantitatively estimate the true amount of plastic in the North Pacific Gyre, whereas our expedition intends to study what we believe to be one of the most impacted areas, so we cannot yet say with statistical certainty that the plastic abundances we are observing are representative of the rest of the gyre. However, when you realize that while we are underway we can only observe a tiny portion of the plastic, and only the the less numerous larger pieces (e.g. greater than 1 cm in diameter) at that, and when you also recall that our cruise track is only covering an infinitesimal fraction of the Pacific, then you begin to understand that there is all likelihood a tremendous amount of trash in the ocean. It is trash that we humans have put there and trash that we as a species must take responsibility for if we wish to protect the health of our oceans.

crabs 008 (Large)A piece of plastic grating, with a pelagic crab, algae, and masses of
flying fish eggs. This piece was floating at the surface and collected
with a dip net off the side of the New Horizon.

Jesse Powell (large) (Large)SEAPLEX scientist Jesse Powell on the deck of the New Horizon.

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Responses

  1. Hi ! I’m Lara’s daughter. I want to know what kind of plankton you’ve seen? Thanks.
    P.S. How’s my mommy?

    • They have seen crustaceans like krill and copepods. They have seen arrow worms and pelagic snails called pteropods. They have also seen lots of little fish. They have also seen some jellyfish. Your mom is doing great! I’ll tell her that you said hello.

  2. Jesse, thank you for your informative and educational post. It is mind boggling to fully realize the size of the ocean.
    That piece of plastic grating really shows what a mess humans are making of our environment and their lack of respect for it.

    I look forward to learning more from you…as you continue heading towards the center of the North Pacific Gyre.

  3. It is interesting that a relatively small piece of plastic is acting as a substrate for three different species in varying parts of their life history. It makes me wonder if not all the impacts of the plastic on the ocean are entirely negative, at least not for all species.
    This is interesting stuff. Keep up the good work!

    • There could be benefits for certain species. However, by benefiting organisms that naturally have pretty small populations, there could be pretty big consequences for the ecosystem. We don’t really know enough about which organism are associated with the plastics to determine the impact on the ecosystem.

  4. [...] SEAPLEX Day 6 « SEAPLEX By Alison Cawood First of all, just to get to our sampling location in the gyre we will have traveled for almost five days continuously. We've had perfect weather, with very little swell, so when you look out from the bridge of the ship you see for six … SEAPLEX – http://seaplexscience.com/ [...]

  5. Jesss, The world is lucky to have people like you and the other researchers aboard. Thank you for all that you do.

    In the late 1970’s, when I was finishing up my studies at Sacramento State, and I had just acquired my pilot’s license, I decided to take my mother for her first ride in a small Cessna 150. I took her from Sacramento Executive Airport out to the Farallon Islands (just west of San Francisco) and we were both shocked to see a large barge with hundreds of barrels on it being dumped off on the southwest side of the island. When I retuned home I made a few phone calls and found out that the City of San Francisco allowed this type of dumping. When I asked what was in the barrels, they replied that they didn’t know. It was apparent from my phone call that this type of dumping had been going on for years.

    Several months later, I read that the dumping practice off shore had been stopped. But there was no mention on what would happen to the barrels that were already dumped.

    With more than twenty-nine years passing since my discovery, maybe some of those barrels have started to decompose and are contributing to the Pacific Garbage Patch.

    Please make your findings public. Our bureaucrat’s (both federal, state, and local) need to be held accountable for what they have allowed to take place. The destruction of our planet has to stop!

    If you would like more information on my findings, please feel free to contact me.

    Be safe and stay in touch.

  6. poor little pelagic crab

    • I would guess that he is actually quite happy. Pelagic crabs can swim, but they are often found resting on pieces of seaweed or other natural debris, as well as on the pieces of plastic.

  7. Will the plastic eventually degrade? I know that it will break up and get smaller and smaller, but will it ever degrade completely? I understand that oil spills will eventually degrade (speed depends largely on the temperature of the water) due to microbial activity. Are there any microbes that can metabolize plastic? How do oil & plastics differ chemically, if both are mainly hydrocarbon chains?

    Thanks

    • As far as we know, the plastic does not ever degrade. However, given a long enough time period (hundreds of years) it could be possible. No body has been studying plastics in the ocean for long enough to really know. The microbes that are used to clean up oil spills are often brought in specifically to do that. They don’t naturally float around waiting for oil. If I remember correctly, the bacteria that are used to help clean up oil spills came from somewhere in the Amazon. As far as I know, bacteria do not break down plastics. Oil is naturally occurring, so it makes sense that something evolved to consume it. However, plastic is not natural thus has no natural “predators”.

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  8. [...] SEAPLEX Day 13 Part 1 Our first post today is from Scripps PhD student Jesse Powell.  This is Jesse’s second posting. [...]

  9. You guys are doing a great service to us all. When I first learned about the garbage patch, I was (to say the least)…sickened by what I saw. The only good thing we can say about what we see, is rthat this floating garbage is giving us a visual on what we can’t see at the bottom of the ocean. Keep up the great work! We thank you for it.


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