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This is about science produced by the California Institute of Technology and originally broadcast by station KPCC in Pasadena California. The programs are made available to this station by national educational radio. This program is about seaweed meeting to discuss this topic. Dr. Peter Liss a man and his guest Dr. Wheeler North associate professor of Environmental Health engineering. Here now is Dr. Leslie Mann. For centuries the ocean and its mysteries has fascinated the sailor landlubber and poet one Victorian poet wrote sand strewn caverns cool and deep where the winds are all asleep where the spent lights quiver and gleam where the salt weed sways in the stream where the sea beasts range all round feed in the woods of their pasture ground. Those lines are by Matthew Arnold from his work the Forsaken mermen. Today we have with us a
far from forsaken Merman Dr. Whelan North graduate of Celtic the Scripps Institute of Oceanography and professor of Environmental Health engineering at Celtic. We as a biologist an engineer can you tell us something about the sand strewn caverns with the salt weed sways in the stream. Yes I've seen a good deal of it myself and I can assure you that California underwater it is beautiful and fascinating as Matthew Arnold depicts it. We have underwater jungles deserts canyons mountains and I've never seen anything to beat it on Dr. And there are some places that equal that. The fascination of the place continues to hold me after many years of looking at it.
I suppose really most of the world is is underneath the oceans. Yes that's right. A little over two thirds of the world underneath the surface of the sea. This is something that we need to know a good deal more about because there are certainly vast resources that are untapped in this watery world. The watery world is quite different from the earthy one that we trade on. Well there are differences and there are similarities to the temperatures in the ocean for instance tend to be more uniform you don't get a tremendous fluctuation between day and night. Something that does fluctuate more than we have here on dry land is the pressure at the upper part of the sea that pressures roughly what it is here on dry land but if you go down for every 33 feet wide your pressure increases by
one atmosphere just goes up very rapidly. Why is the precious so much more and what does it mean to be under the sea. Well it doesn't mean anything to be stunned or to see if he's made entirely out of solid substance or liquid such as water because he's are incompressible But if he has air spaces in his body such as a man does why these compress as you go down to greater and greater pressures and this can cause problems if the pressure inside and outside are equalized you can get squeezes which divers experience and they're quite harmful. I might mention some of the other differences light intensities are always much dimmer underwater and after you get down three or four hundred feet there's blackness takes a lot more energy to
move underwater because the watery medium is so much more viscous. Does that mean that the Sienna mills are relatively stronger than horses or dogs. No it turns out that you know they move rather slowly or if they're rapid movers they're much more streamlined than land animals with the possible exception of birds. But I suppose in many ways they there are similarities between these underwater environment and our earth. Very definitely especially when we get in the biological field we find many of the same basic principles. The plants are all important underwater as they are on dry land because they capture the energy of the sun which is essentially what keeps this all going. Photosynthesis is the process whereby plants convert light energy
to chemical energy in chemicals in their bodies and then some animals the herbivores the plants the carnivores are meat eaters eat the herbivores so that everything ultimately depends on the plants. But on this question of like you said it was very Dr. Lewis is right. And plants can live only in the uppermost layers of the sea. If they sink down to these dark areas they perish. One reason the shore are so prolific is because the bottom of course keeps the plants from sinking and some plants are actually attached to the bottom just like plants grow in the ground here upon dry land. This is the importance of sea weeds really because these
can achieve huge massive forests and form extremely rich environments in the ocean. Now people talk about seaweed but in California the wood is always kelp. Does that mean the same thing. No kelp is a particular kind of seaweed it's a brown one. It's. Generally the Celts are huge enormous plants and one of the important Celts that we have here in Southern California the giant kelp is has been called the longest plant in the world. The ones we have here only 200 feet long but they've been reported from the Southern Hemisphere as blanks ranging from 300 to a thousand feet is this length.
Do they grow straight upwards or do they just sort of stream out as Matthew Arnold has it. Well when there's a strong current running they stream out. But when there's slack water the kelp has a little gas bobs on it that it up and it comes straight up to the surface and spreads out over the top of the sea to form a kind of a canopy. This canopy is particularly important here in Southern California because we cut it away and use it. Why your associates especially concerned with cutting away the stuff I mean does it get in the way of shipping or what is the real purpose. Oh no no it's used by man in all kinds of things for example and goes into fertilizers into animal feeds. But one of the most important uses is an exotic chemical that's extracted from it called algae algae and what exactly.
That's a funny name one doesn't hear it much. What is this. Y'all probably eat two or three times today without realizing it gets into. He used an ice cream. When you have a little bit of algae in an ice cream why ice crystals are reduced and you don't get this rather granular ice cream. Good heavens whatever sort of things do they do with it. Yeah it's put in salad dressing it keeps the oil in the water of the dressing mixed up in a permanent emotion. We find it in toothpaste textiles paints for printing. Firefighting pharmaceuticals it's even put into beer where it tends to maintain the foam stable on top of the beer and makes a glass of beer look like a glass of beer. Well I like that touch about the beer we lead but tell me what did people use to make beer or textiles or ice cream before they knew about algae and have they
always used. Can you get it. No actually allergen was discovered about 1883 by a British chemist named sound Ferd and it went for almost 50 years without having any particular use although Sanford felt that it would. It was a most versatile chemical. But then some people down in San Diego here began to find all kinds of uses for it in industry and through their ingenuity and resources. Natural resources we. Have this extremely valuable kelp harvesting industry in Southern California. About a hundred thousand tons of Calabar harvested a year. Is this the main place in the world where they harvest this kelp or are there other places it's collected also in giant kelp I might say
grows all over the world as well as some of the other smaller Celts an allergen can be gotten from any of these allergen is manufactured in Europe and there's an algae company or two on the East Coast of America. But our southern California industry is by far the largest. Is that because you need relatively warm waters do you get the same sort of kelp and sea weed growth in the North Sea for example you get. Well let me say first of all that we have a fairly cold waters here in Southern California because the prevailing currents come down to us from the Gulf of Alaska and they tend to favor the colder waters of the world. You actually find a much reduced in the tropics. The big jungles are found around the. Land masses of the Southern
Hemisphere and occasionally here and there in the northern hemisphere. Actually a giant cow doesn't grow in European waters and they have to use some of the smaller ones. I see but of course when we think about the treasures from the sea most people think about all the various fishes and other spiny shiny creatures which can be pulled out and which make such a delicious lunch or dinner. Are they connected with the kelp in any way. I'm glad you mentioned that because they're very intimately connected with kelp and with other seaweed. A good many of them eat this material directly as food. There are schools of fish is browse through kelp beds just like cows go through a pasture and then of course as I've said before there are the meat eaters the carnivores that live on
these herbivores and the kelp beds are truly jungles they're just teeming with life of all kinds. They're animals we harvest from the kelp beds in addition to the fishes or the lobster and the abalone. I always thought of the lobster as living among rocks and I never thought of kelp as being among the rocks is there. Is that the way things are or am I just mistaken. No. Well kelp and lobster both live among the rocks kelp doesn't have a true root like a land plant does it has what is called a hold fast at the bottom man and this is just an anchoring structure. Oh I see so the kelp crew is no nutrition from the earth in the same way that we think of a plant. That's right the kelp gets all its. It's minerals and so forth out of the sea itself and it absorbs and
throughout all the tissues of the plant not just from the root. You know we're talking about absorbing things from the sea itself. People are always worried in California about the way we dispose of wastes upwards in the form of smog. And of course Aqua didn't the ocean into the form of sewage. Does this have any effect on the life in the ocean around our shores here. Well I might say at the start that this is an extremely complex problem and one in which I am very greatly interested because the amount of sewage that we're putting out into the ocean increases by leaps and bounds each year. And I'd hate to see our marvelous resources sort of disappear and vanish in a sea of sewage. Does a sewage kill everything then. No. Now and we've read a great many tests
of. And I might say that our engineers have very cleverly designed dispersing devices that really mix the sewage up fairly with the sea water so it's very quickly diluted by factors of a hundred to one up sometimes up to 500 to one. But you get these tremendous dilutions it's not toxic to anything. So really we have this completely under control and it doesn't make any difference to anything that goes on down there. I wouldn't go so far as to say that because one of the things that has disturbed me and disturbed a great many people is that many of our richest kelp beds that are near these submarine outfalls discharge sewage many of these kelp beds have disappeared in recent times and the disappearance if you look at aerial photographs taken year after year
that part of it can't bad nearest discharge is the part that disappears first and then it. It leaves us at increasing distances that's pretty good evidence that there's some relationship there. But I thought you just said that the sewage didn't affect the kelp beds. Well what we think happens in these cases is that the sewage upsets a rather delicate ecological balance. What does ecological mean. Well ecology has been defined as scientific natural history. I'm sure many of the listeners love to go out and make observations in nature on plants and animals and this is a very rewarding pastime and if you make a lifetime profession of it and and record these observations. And accumulate them compare
them with other ones and short use and methods of science why then you're an ecologist. I see so he studies the relationship of everything to everything else. Yes that's a good way of putting it because that's the way it often turns out. You have so many things going on that you have. You can't just isolate one of them and study it. You know I'm fascinated by your talk about sea urchins. I always remember being brought up with pictures of street urchins. These are funny little slum boys with hair while they see a chins do they wander around street corners. Actually I believe the word comes from the French where the street urchins were called and long before anybody called marine animals by the same name and then one day somebody compared this little spiny pin cushion from the sea
to the head of St.. And everybody thought that was so appropriate that they proceeded to call a marine animal an urchin ever since. I love that touch. But is the sea urchin really an animal or is it a plant. Or is there a distinction for that matter. Well for our purposes I think there's a clear distinction. Sometimes when you get down to the microscopic level you have difficulties. In answer to your other question the urchin is very definitely an animal and it's a rather voracious animal it eats plant material and it's a very wasteful eater. It doesn't ever get up off the bottom very far. It doesn't have any limbs or hands to hold on with. So it just grazes around the
bottom of these kelp plants takes a few bites and the anchorage is lost in the main part of the plant maybe 200 feet long drifts away and is lost to all the other animals. But now when this plant drifts away. In other words when you cut the bottom off of this plant does that mean it's going to die. It probably can survive in the drifting state for a few months but sooner or later it gets carried into the tropics. And as I've said it can't withstand warm temperatures so it dies. Talking about the tropics I'd like to make a little excursion. What about the Sargasso Sea that we always read about in romantic novels. This is a sort of a gigantic whirlpool sitting off the West Indies in the Atlantic Ocean and the currents just go. In a circular path. Round and round apparently one of the drifting sea weeds has gotten in there and flourished. This particular
seaweed is called the sarg awesome weed giving the name Sargasso Sea to the area. I see that normally of course that seaweed is not rooted on the bottom in any way the ocean must be terribly deep in those regions. That's right it's not rooted it can it can withstand the warm water so it just flourishes there. So matter of fact there is a similar circular movement goes around the South Pole. I should say the Antarctic continent. It doesn't happen in the at the northern end of the planet because the land mass is in the way but this west wind drift its call goes around the South Pole and Makar these giant kelp plants Macra sesterces is its name. Apparently go around endlessly there and they seem to survive. People of color the Macra Cistus see in
comparison to the Sargasso Sea. I guess that well you know I think I'd like to get back to these TA's little head little Ruffins the actions that seem to have these very bad and messy eating habits they spill everything and they just take a bite of one or two things and then they'd leave it how I mean how are we going to get rid of these. They must be a serious menace to the kelp beds. Well ordinarily Nature takes care. The urchins because after they've gotten rid of all the callup and all the other animals starved the urchins either have to move away and find greener pastures or they starve to death themselves. Once the urchins are gone why then the vegetation comes back and with it all the richness of the associated animal life in the ocean. You talk about these actions moving away but they don't just simply take a
bus or they have no feet. How do they move away while they have these spines that stick out all over them. Make them look like a pin question and they have little flashy like protuberances little arms or tubes that stick out and they have suckers on the end that they can grasp the bottom with and they can actually move along at a rate of three or four feet an hour and presumably they cover a matter of a few thousand feet or a thousand feet or so and a year are capable of doing this. How do they know what way to go. Well if they're being guided by the odor of sea weeds somewhere else. This tends to move them off in that direction if there is a sea weeds up current from
them. And in fact we've detected this in some experiments we've gone into these areas where urchins are completely dominant and we've anchored seaweeds up off the bottom so that they can't get at them they're just two or three feet off the bottom and the urchins come congregating in under them. So we know that they can detect these plants. Good heavens. So now we discover that under the ocean we have these great beds of kelp that are almost like wheat or something that you might have on land and that we have urchins which are somewhat like the pests that plague from is you'll be suggesting that we're actually farming under the ocean soon. Well I think we are because we've found ways to control the urchins but we. Use a toxic but cheap chemical called quicklime that comes in lumps form and we go out and sprinkle it on the water and it drops
down and where it hits an urchin it kills him. And when you've gotten rid of the urchins why you can bring the kelp back much quicker than it would if you had to wait for the urchins to starve to death. Does this have any effect on any of the other creatures living underneath. Well for the most part no if you control your dosage properly the urchins appear to be much more sensitive then other animals so that if you just sprinkle your quicklime very lightly you can clean out the urchins and not harm anything else. You know we know we introduced you as the one from say can Merman but I suppose you do most of your work at a desk and with mathematics in great serious terms rather than really going out there and seeing what's happening. Well I do a considerable amount of work at my desk Yes but I get out into the ocean usually at least once a week and sometimes three or four times.
Are you actually going to go diving underneath the ocean then do yo yo and. Right now we're trying to transplant some kelp barren area down off a lawyer. I see you. You wear the normal skin diving equipment is this a dangerous occupation. Well it's sort of like driving an automobile or handling a loaded gun. If you do it improperly you can be a hazard to yourself and others. But if you do it properly you can accomplish a great deal with it. Have a good deal of fun. And and it really isn't hazardous when done properly. Have you ever had any experiences with any of these monsters of the deep during your trips under the ocean. Well I had a shark once come in and look me over. And the important thing when a shark is looking you over is to look him
over because if you turn and swim away an awful flat fly he'll be right on your fins nibbling at them. It's like if you run away from from an angry dog he'll chase you. But if you stand your ground and show him that you're not afraid you stand a much better chance. I see. How deep do you go when you when you go how deep can people go comfortably. Skin diving. Well with the ordinary apparatus it's available here. We can go down 200 feet but really you can't do much more work than comfortably and down a hundred feet at the present time. This I might say is if you're thinking of using the resources of the sea working down to 100 feet all around the world gives an area the size of the continent of Africa
to develop. Well that is a really fascinating picture of two thirds of the world. We have kelp. We have a urchins. We have sea beasts and we have men working down there in relative comfort 100 feet below the surface of the ocean. Thank you very much. It's most interesting. This was about science with host Dr. Peter listen and his guest Dr. Wheeler North associate professor of Environmental Health engineering joined us again for our next program went to more prominent scientists will discuss a topic of interest about science is produced by the California Institute of Technology and is originally broadcast by station KPCC in Pasadena California. The programs are made available to this station by national educational radio. This is the national educational radio network.
About science
About seaweed
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California Institute of Technology
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University of Maryland (College Park, Maryland)
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This program connections between seaweed and science. The guest for this program is Dr. Wheeler North, California Institute of Technology.
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Interview series on variety of science-related subjects, produced by the California Institute of Technology. Features three Cal Tech faculty members: Dr. Peter Lissaman, Dr. Albert R. Hibbs, and Dr. Robert Meghreblian.
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Guest: North, Wheeler J.
Producing Organization: California Institute of Technology
Producing Organization: KPPC
Speaker: Lissaman, Peter B. S.
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University of Maryland
Identifier: 66-40-5 (National Association of Educational Broadcasters)
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Duration: 00:27:59
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Chicago: “About science; About seaweed,” 1966-10-10, University of Maryland, American Archive of Public Broadcasting (GBH and the Library of Congress), Boston, MA and Washington, DC, accessed May 28, 2024,
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APA: About science; About seaweed. Boston, MA: University of Maryland, American Archive of Public Broadcasting (GBH and the Library of Congress), Boston, MA and Washington, DC. Retrieved from