WEBVTT - How Do Ecosystems Work? 0:00:01.920 --> 0:00:06.520 Welcome to brain Stuff production of I Heart Radio. Hey 0:00:06.600 --> 0:00:10.080 brain Stuff Lauren boglebam here. Let's say you meet a 0:00:10.080 --> 0:00:12.959 person on a flight from Boston to Brisbane. The two 0:00:12.960 --> 0:00:14.520 of you are seated next to each other for a 0:00:14.560 --> 0:00:18.960 couple dozen hours, and you talk the entire time about books, politics, 0:00:19.000 --> 0:00:22.400 current events, religion, the weather, et cetera. You hear some 0:00:22.480 --> 0:00:25.160 of their personal stories, observe the way they eat and drink. 0:00:25.480 --> 0:00:27.240 You watch them play a game on their phone, and 0:00:27.400 --> 0:00:30.360 notice that they snore when they sleep. By the time 0:00:30.400 --> 0:00:32.360 you get to Australia, you feel you've got a pretty 0:00:32.400 --> 0:00:34.839 good sense of who this person is. You've become friends 0:00:34.840 --> 0:00:38.440 and exchange contact info even But then their entire family 0:00:38.479 --> 0:00:40.600 shows up to meet them at the airport, and immediately 0:00:40.640 --> 0:00:43.239 you learn more and some of the assumptions you made 0:00:43.280 --> 0:00:47.680 on the plane have to be reevaluated given this new input. Later, 0:00:47.800 --> 0:00:49.520 they invite you to a family dinner at their home, 0:00:49.640 --> 0:00:52.680 and their story broadens again. The smell of their house, 0:00:52.760 --> 0:00:55.280 the taste of their drinking water, the view from their porch, 0:00:55.320 --> 0:00:59.120 and the contents of their refrigerator and bookcases speak volumes 0:01:00.000 --> 0:01:02.480 about These details reinforce what you thought you already knew, 0:01:02.680 --> 0:01:05.920 and some change your mind. At some point your observations 0:01:05.959 --> 0:01:08.840 become not about the person themselves, but about the whole 0:01:08.880 --> 0:01:12.959 system in which they live. In order to understand anything, 0:01:13.080 --> 0:01:16.360 it's helpful to understand everything, or as much as you 0:01:16.400 --> 0:01:19.720 possibly can. In the study of ecology, the concept of 0:01:19.720 --> 0:01:23.240 an ecosystem acknowledges the fact that, as the nineteenth century 0:01:23.319 --> 0:01:26.080 naturalist John Muir said, when we try to pick out 0:01:26.120 --> 0:01:29.000 anything by itself, we find it hitched to everything else 0:01:29.000 --> 0:01:32.759 in the universe. But it's difficult to look at everything 0:01:32.800 --> 0:01:35.360 at once, and natural systems, of all the things we 0:01:35.360 --> 0:01:38.600 can investigate with science, are particularly hard to nail down, 0:01:38.959 --> 0:01:44.000 but ecologists are always trying. In five and English botanist 0:01:44.120 --> 0:01:48.240 named Arthur Tansley, strongly influenced by Danish botanist Eugenie's Varming, 0:01:48.600 --> 0:01:51.720 introduced the term ecosystem in a paper titled The Use 0:01:51.760 --> 0:01:54.760 and Abuse of Vegetal Concepts and Terms that was published 0:01:54.760 --> 0:01:58.520 in the journal Ecology. He defined an ecosystem as the 0:01:58.560 --> 0:02:02.520 whole system included not only the organism complex, but also 0:02:02.600 --> 0:02:05.480 the whole complex of physical factors forming what we call 0:02:05.640 --> 0:02:09.560 the environment. What Tansley was trying to get at was 0:02:09.600 --> 0:02:11.720 the idea that you can look at a natural system 0:02:11.760 --> 0:02:13.840 at a bunch of different levels, and that there was 0:02:13.880 --> 0:02:16.760 one level that didn't have a name yet. For instance, 0:02:16.800 --> 0:02:19.560 you could look at a wolverine that's a single organism, 0:02:19.600 --> 0:02:21.840 just like the person you met on the plane, but 0:02:22.040 --> 0:02:24.680 that wolverine doesn't live in a vacuum. It lives in 0:02:24.720 --> 0:02:28.040 a population of other wolverines that interact and organize themselves 0:02:28.040 --> 0:02:31.720 in specific ways. Thus, an ecologist can choose to investigate 0:02:31.720 --> 0:02:35.160 wolverines at a population level, but that's not the only 0:02:35.160 --> 0:02:38.720 way to study wolverines. Ecologists also talk about communities of 0:02:38.760 --> 0:02:42.000 living things. A wolverine doesn't just interact with members of 0:02:42.000 --> 0:02:44.799 its own species. It's an omnivore, so it eats other 0:02:44.840 --> 0:02:47.880 animals like moose and rabbit, as well as berries, roots, 0:02:47.880 --> 0:02:51.320 and eggs. It gets parasites, It digs burrows that affect 0:02:51.400 --> 0:02:55.040 roots systems of plants. A wolverine influences lots of living 0:02:55.080 --> 0:02:58.240 things in its home territory, and those living things affect 0:02:58.280 --> 0:03:02.800 it tans. These definition of ecosystem acknowledged that there was 0:03:02.840 --> 0:03:05.720 a level of scientific inquiry that could encompass all the 0:03:05.760 --> 0:03:08.800 living organisms in the wolverines home. In addition, to the 0:03:08.800 --> 0:03:13.000 stuff that's not alive. We spoke with Stephen Carpenter, a 0:03:13.040 --> 0:03:15.880 scientist in the Center for Limnology at the University of 0:03:15.880 --> 0:03:20.840 Wisconsin Madison. He said the ecosystem concept ecologists now use 0:03:20.960 --> 0:03:23.560 has been refined since it was first introduced by Tansley 0:03:23.600 --> 0:03:27.680 almost a century ago. Ecosystem science studies the interactions of 0:03:27.720 --> 0:03:30.919 all the living and non living entities in a specified place. 0:03:31.560 --> 0:03:35.200 This definition is consistent with modern concepts of energy, nutrient flow, 0:03:35.280 --> 0:03:41.680 and biogeochemistry, which barely existed during Tansley's career. The allure 0:03:41.800 --> 0:03:44.160 of the ecosystem to scientists has to do with the 0:03:44.280 --> 0:03:46.840 system part of the word. If you look at an 0:03:46.840 --> 0:03:50.280 ecosystem like you'd look at a computer, then an ecosystem 0:03:50.320 --> 0:03:53.520 like a coral reef runs very similar software to that 0:03:53.600 --> 0:03:56.560 of an arctic tundra where the wolverine lives, or to 0:03:56.600 --> 0:03:59.880 that of a tropical forest, meaning that the same base 0:04:00.320 --> 0:04:05.280 large scale processes can apply anywhere organic matter decomposes and 0:04:05.320 --> 0:04:08.120 becomes nourishment for something else. In a grassland or a 0:04:08.120 --> 0:04:12.839 mountain stream, nutrients like carbon, phosphorus, nitrogen, and sulfur get 0:04:12.880 --> 0:04:16.200 passed around like monopoly money everywhere. It just happens a 0:04:16.200 --> 0:04:18.599 lot faster, and there's a lot more of it in 0:04:18.720 --> 0:04:22.680 say a tropical rainforest than in most deserts. Diseases are 0:04:22.720 --> 0:04:25.880 carried along on water or air or by hapless organisms 0:04:25.880 --> 0:04:29.200 in similar ways, and wherever you look, if a top 0:04:29.200 --> 0:04:33.120 predator is removed from the ecosystem, the entire dynamic changes, 0:04:33.400 --> 0:04:35.560 be it on a mountaintop in the Andes or in 0:04:35.680 --> 0:04:40.599 Yellowstone National Park in Wyoming. This is to say ecosystems 0:04:40.640 --> 0:04:43.760 are a good topic for theory, as a framework for 0:04:43.880 --> 0:04:48.720 hanging ideas about how complex natural systems work. But while 0:04:48.760 --> 0:04:52.720 being a theoretical idea, an ecosystem is also an actual thing. 0:04:53.360 --> 0:04:57.920 It's just a thing without clear boundaries. According to Eugene 0:04:57.960 --> 0:05:02.080 Odom's Fundamentals of Ecology, first wished in three you know 0:05:02.200 --> 0:05:05.360 you've identified the edge of an ecosystem when more material 0:05:05.440 --> 0:05:09.120 and energy is cycling within the boundary than crossing over it. 0:05:09.880 --> 0:05:13.159 So a riffle and a stream cannot be an ecosystem 0:05:13.200 --> 0:05:16.040 because all those certain types of fish and aquatic invertebrates 0:05:16.279 --> 0:05:19.080 like to live in a fast, shallow section of a stream. 0:05:19.160 --> 0:05:22.120 Abundant material is flowing into and out of the riffle 0:05:22.240 --> 0:05:24.960 all the time. Some might stay in it for a while, 0:05:25.200 --> 0:05:27.600 but most of it leaves pretty soon after it arrives. 0:05:28.080 --> 0:05:31.240 Even the sediment and rocks don't stay forever. When they move, 0:05:31.520 --> 0:05:34.520 it's mostly not inside the riffle, but into or out 0:05:34.560 --> 0:05:39.479 of it. On the other hand, watersheds are classic ecosystem boundaries, 0:05:39.720 --> 0:05:43.080 but they're extremely tricky as well. The river itself is 0:05:43.080 --> 0:05:46.400 an ecosystem because although a lot of material and energy 0:05:46.480 --> 0:05:49.159 passes in and out of it all the time, leaves 0:05:49.160 --> 0:05:52.480 and soil and dead animals fall in. Terrestrial animals use 0:05:52.560 --> 0:05:55.159 the river as a grocery store, et cetera. A lot 0:05:55.160 --> 0:05:58.560 of cycling within it too, So although the river in 0:05:58.600 --> 0:06:01.480 itself can be considered an eaty system, it's difficult to 0:06:01.560 --> 0:06:03.839 view the river and the dry land around it is 0:06:03.880 --> 0:06:07.640 truly separate, since material and energy are being exchanged across 0:06:07.680 --> 0:06:11.160 the literally fluid boundary all the time in both directions. 0:06:11.680 --> 0:06:15.000 Rivers flood after all, and deposit nutrient rich sediment on 0:06:15.080 --> 0:06:20.919 the land. Ecosystems then are not static. We also spoke 0:06:20.960 --> 0:06:23.919 with Kathleen Weathers, and ecologist at the Carey Institute of 0:06:23.960 --> 0:06:28.520 Ecosystem Studies. She said the a biotic and biotic are 0:06:28.600 --> 0:06:32.120 essential parts of the ecosystem, and they have boundaries, albeit 0:06:32.240 --> 0:06:36.200 human defined boundaries. And not only do ecosystems have structure 0:06:36.240 --> 0:06:39.760 and function, but these are controlled by many factors and 0:06:39.960 --> 0:06:48.560 that ecosystems change throughout time. Today's episode was written by 0:06:48.600 --> 0:06:51.480 Jescelin Shields and produced by Tyler Claying. Brain Stuff is 0:06:51.480 --> 0:06:53.560 a production of I Heart Radio's How Stuff Works. For 0:06:53.640 --> 0:06:55.400 more in this and lots of other topics, visit our 0:06:55.440 --> 0:06:58.000 home planet, how stuff Works dot com and for more 0:06:58.040 --> 0:07:00.560 podcast in my heart Radio because thy heart radio, app, 0:07:00.680 --> 0:07:03.279 Apple Podcasts, or wherever you listen to your favorite shows. 0:07:14.360 --> 0:07:14.400 H