Quiz by Danielle_BIA
This ESL Video quiz titled, "TOEFL Quiz 15: Algae," is for advanced English as a Second Language students who are studying English online to develop fluency in English.
Some years ago, I set out to try to understand if there was a
possibility to develop biofuels on a scale that would actually
compete with fossil fuels but not compete with agriculture for
water, fertilizer or land.
So here's what I came up with. Imagine that we build an enclosure
where we put it just underwater, and we fill it with wastewater and
some form of microalgae that produces oil, and we make it out of
some kind of flexible material that moves with waves underwater,
and the system that we're going to build, of course, will use solar
energy to grow the algae, and they use CO2, which is good, and
they produce oxygen as they grow. The algae that grow are in a
container that distributes the heat to the surrounding water, and
you can harvest them and make biofuels and cosmetics and
fertilizer and animal feed, and of course you'd have to make a large
area of this, so you'd have to worry about other stakeholders like
fishermen and ships and such things, but hey, we're talking about
biofuels, and we know the importance of potentially getting an
alternative liquid fuel.
Why are we talking about microalgae? Here you see a graph
showing you the different types of crops that are being considered
for making biofuels, so you can see some things like soybean,
which makes 50 gallons per acre per year, or sunflower or canola or
jatropha or palm, and that tall graph there shows what microalgae
can contribute. That is to say, microalgae contributes between
2,000 and 5,000 gallons per acre per year, compared to the 50
gallons per acre per year from soy.
So what are microalgae? Microalgae are micro -- that is, they're
extremely small, as you can see here a picture of those single-
celled organisms compared to a human hair. Those small organisms
have been around for millions of years and there's thousands of
different species of microalgae in the world, some of which are the
fastest-growing plants on the planet, and produce, as I just showed
you, lots and lots of oil.
Now, why do we want to do this offshore? Well, the reason we're
doing this offshore is because if you look at our coastal cities, there
isn't a choice, because we're going to use waste water, as I
suggested, and if you look at where most of the waste water
treatment plants are, they're embedded in the cities. This is the city
of San Francisco, which has 900 miles of sewer pipes under the city
already, and it releases its waste water offshore. So different cities
around the world treat their waste water differently. Some cities
process it. Some cities just release the water. But in all cases, the
water that's released is perfectly adequate for growing microalgae.
So let's envision what the system might look like. We call it OMEGA,
which is an acronym for Offshore Membrane Enclosures for Growing
Algae. At NASA, you have to have good acronyms.
So how does it work? I sort of showed you how it works already. We
put waste water and some source of CO2 into our floating structure,
and the waste water provides nutrients for the algae to grow, and
they sequester CO2 that would otherwise go off into the
atmosphere as a greenhouse gas. They of course use solar energy
to grow, and the wave energy on the surface provides energy for
mixing the algae, and the temperature is controlled by the
surrounding water temperature. The algae that grow produce
oxygen, as I've mentioned, and they also produce biofuels and
fertilizer and food and other bi-algal products of interest.
And the system is contained. What do I mean by that? It's modular.
Let's say something happens that's totally unexpected to one of the
modules. It leaks. It's struck by lightning. The waste water that
leaks out is water that already now goes into that coastal
environment, and the algae that leak out are biodegradable, and
because they're living in waste water, they're fresh water algae,
which means they can't live in salt water, so they die. The plastic
we'll build it out of is some kind of well-known plastic that we have
good experience with, and we'll rebuild our modules to be able to
reuse them again.
So we may be able to go beyond that when thinking about this
system that I'm showing you, and that is to say we need to think in
terms of the water, the fresh water, which is also going to be an
issue in the future, and we're working on methods now for
recovering the waste water.
The other thing to consider is the structure itself. It provides a
surface for things in the ocean, and this surface, which is covered
by seaweeds and other organisms in the ocean, will become
enhanced marine habitat so it increases biodiversity. And finally,
because it's an offshore structure, we can think in terms of how it
might contribute to an aquaculture activity offshore.
So you're probably thinking, "Gee, this sounds like a good idea.
What can we do to try to see if it's real?" Well, I set up laboratories
in Santa Cruz at the California Fish and Game facility, and that
facility allowed us to have big seawater tanks to test some of these
ideas. We also set up experiments in San Francisco at one of the
three waste water treatment plants, again a facility to test ideas.
And finally, we wanted to see where we could look at what the
impact of this structure would be in the marine environment, and
we set up a field site at a place called Moss Landing Marine Lab in
Monterey Bay, where we worked in a harbor to see what impact this
would have on marine organisms.
The laboratory that we set up in Santa Cruz was our skunkworks. It
was a place where we were growing algae and welding plastic and
building tools and making a lot of mistakes, or, as Edison said, we
were finding the 10,000 ways that the system wouldn't work. Now,
we grew algae in waste water, and we built tools that allowed us to
get into the lives of algae so that we could monitor the way they
grow, what makes them happy, how do we make sure that we're
going to have a culture that will survive and thrive. So the most
important feature that we needed to develop were these so-called
photobioreactors, or PBRs. These were the structures that would be
floating at the surface made out of some inexpensive plastic
material that'll allow the algae to grow, and we had built lots and
lots of designs, most of which were horrible failures, and when we
finally got to a design that worked, at about 30 gallons, we scaled it
up to 450 gallons in San Francisco.
So let me show you how the system works. We basically take waste
water with algae of our choice in it, and we circulate it through this
floating structure, this tubular, flexible plastic structure, and it
circulates through this thing, and there's sunlight of course, it's at
the surface, and the algae grow on the nutrients.
But this is a bit like putting your head in a plastic bag. The algae are
not going to suffocate because of CO2, as we would. They suffocate
because they produce oxygen, and they don't really suffocate, but
the oxygen that they produce is problematic, and they use up all the
CO2. So the next thing we had to figure out was how we could
remove the oxygen, which we did by building this column which
circulated some of the water, and put back CO2, which we did by
bubbling the system before we recirculated the water. And what you
see here is the prototype, which was the first attempt at building
this type of column. The larger column that we then installed in San
Francisco in the installed system.
So the column actually had another very nice feature, and that is the
algae settle in the column, and this allowed us to accumulate the
algal biomass in a context where we could easily harvest it. So we
would remove the algaes that concentrated in the bottom of this
column, and then we could harvest that by a procedure where you
float the algae to the surface and can skim it off with a net.
So we wanted to also investigate what would be the impact of this
system in the marine environment, and I mentioned we set up this
experiment at a field site in Moss Landing Marine Lab. Well, we
found of course that this material became overgrown with algae,
and we needed then to develop a cleaning procedure, and we also
looked at how seabirds and marine mammals interacted, and in fact
you see here a sea otter that found this incredibly interesting, and
would periodically work its way across this little floating water bed,
and we wanted to hire this guy or train him to be able to clean the
surface of these things, but that's for the future.
Now really what we were doing, we were working in four areas. Our
research covered the biology of the system, which included
studying the way algae grew, but also what eats the algae, and what
kills the algae. We did engineering to understand what we would
need to be able to do to build this structure, not only on the small
scale, but how we would build it on this enormous scale that will
ultimately be required. I mentioned we looked at birds and marine
mammals and looked at basically the environmental impact of the
system, and finally we looked at the economics, and what I mean by
economics is, what is the energy required to run the system? Do
you get more energy out of the system than you have to put into
the system to be able to make the system run? And what about
operating costs? And what about capital costs? And what about,
just, the whole economic structure?
So let me tell you that it's not going to be easy, and there's lots
more work to do in all four of those areas to be able to really make
the system work. But we don't have a lot of time, and I'd like to
show you the artist's conception of how this system might look if
we find ourselves in a protected bay somewhere in the world, and
we have in the background in this image, the waste water treatment
plant and a source of flue gas for the CO2, but when you do the
economics of this system, you find that in fact it will be difficult to
make it work. Unless you look at the system as a way to treat waste
water, sequester carbon, and potentially for photovoltaic panels or
wave energy or even wind energy, and if you start thinking in terms
of integrating all of these different activities, you could also include
in such a facility aquaculture. So we would have under this system a
shellfish aquaculture where we're growing mussels or scallops. We'd
be growing oysters and things that would be producing high value
products and food, and this would be a market driver as we build
the system to larger and larger scales so that it becomes,
ultimately, competitive with the idea of doing it for fuels.
So there's always a big question that comes up, because plastic in
the ocean has got a really bad reputation right now, and so we've
been thinking cradle to cradle. What are we going to do with all this
plastic that we're going to need to use in our marine environment?
Well, I don't know if you know about this, but in California, there's a
huge amount of plastic that's used in fields right now as plastic
mulch, and this is plastic that's making these tiny little greenhouses
right along the surface of the soil, and this provides warming the
soil to increase the growing season, it allows us to control weeds,
and, of course, it makes the watering much more efficient. So the
OMEGA system will be part of this type of an outcome, and that
when we're finished using it in the marine environment, we'll be
using it, hopefully, on fields.
Where are we going to put this, and what will it look like offshore?
Here's an image of what we could do in San Francisco Bay. San
Francisco produces 65 million gallons a day of waste water. If we
imagine a five-day retention time for this system, we'd need 325
million gallons to accomodate, and that would be about 1,280 acres
of these OMEGA modules floating in San Francisco Bay. Well, that's
less than one percent of the surface area of the bay. It would
produce, at 2,000 gallons per acre per year, it would produce over 2
million gallons of fuel, which is about 20 percent of the biodiesel,
or of the diesel that would be required in San Francisco, and that's
without doing anything about efficiency.
Where else could we potentially put this system? There's lots of
possibilities. There's, of course, San Francisco Bay, as I mentioned.
San Diego Bay is another example, Mobile Bay or Chesapeake Bay,
but the reality is, as sea level rises, there's going to be lots and lots
of new opportunities to consider. (Laughter)
So what I'm telling you about is a system of integrated activities.
Biofuels production is integrated with alternative energy is
integrated with aquaculture.
I set out to find a pathway to innovative production of sustainable
biofuels, and en route I discovered that what's really required for
sustainability is integration more than innovation.
Long term, I have great faith in our collective and connected
ingenuity. I think there is almost no limit to what we can accomplish
if we are radically open and we don't care who gets the credit.
Sustainable solutions for our future problems are going to be
diverse and are going to be many. I think we need to consider
everything, everything from alpha to OMEGA. Thank you. (Applause)
(Applause) Chris Anderson: Just a quick question for you, Jonathan.
Can this project continue to move forward within NASA or do you
need some very ambitious green energy fund to come and take it by
the throat? Jonathan Trent: So it's really gotten to a stage now in
NASA where they would like to spin it out into something which
would go offshore, and there are a lot of issues with doing it in the
United States because of limited permitting issues and the time
required to get permits to do things offshore. It really requires, at
this point, people on the outside, and we're being radically open
with this technology in which we're going to launch it out there for
anybody and everybody who's interested to take it on and try to
make it real. CA: So that's interesting. You're not patenting it.
You're publishing it. JT: Absolutely. CA: All right. Thank you so
much. JT: Thank you. (Applause)
TOEFL Quiz 15: Algae
Quiz #: 12374
1. All of the following are true of microalgae EXCEPT
2. According to the professor, why do we need to create the enclosures offshore?
3. The algae need all of the following to grow EXCEPT
4. According to the professor, photobioreactors
5. According to the professor, why did the scientists need to find a way to remove the oxygen?
6. In addition to looking at environmental factors, the professor says that his team also evaluated
7. In addition to using the algae to produce biofuel, the team's original intent, the OMEGA project could also produce
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