1 00:00:00 --> 00:00:04 And I just wanted to mention a few more things about community ecology 2 00:00:04 --> 00:00:09 before I move onto the final lecture which I've forecasted to you where 3 00:00:09 --> 00:00:14 I'm going to try to tie everything together through a research story 4 00:00:14 --> 00:00:18 that I want to tell you about. But before we go to that, I just 5 00:00:18 --> 00:00:23 want to present one very famous ecological experiment 6 00:00:23 --> 00:00:28 from your textbook. Because what we're trying to do here 7 00:00:28 --> 00:00:32 in this lecture is bring together the first set of lectures where we 8 00:00:32 --> 00:00:37 talked about biogeochemical cycles and productivity which we think of 9 00:00:37 --> 00:00:41 as the function of ecosystems with the last set of lectures where we 10 00:00:41 --> 00:00:46 talked about population biology, community structure where we 11 00:00:46 --> 00:00:51 actually talk about different species and how they interact. 12 00:00:51 --> 00:00:55 And the structure of the community effects productivity 13 00:00:55 --> 00:01:00 in biogeochemistry. And these processes in turn feed 14 00:01:00 --> 00:01:04 back and affect the structure of the community. And this is something 15 00:01:04 --> 00:01:08 ecologists have known, but it's not easy to demonstrate 16 00:01:08 --> 00:01:12 this experimentally. So one of the famous experiments 17 00:01:12 --> 00:01:16 was done by David Tillman of the University of Minnesota because 18 00:01:16 --> 00:01:20 these are very long-term experiments. And, of course, 19 00:01:20 --> 00:01:24 it's easier to do these kinds of experiments with plants because they 20 00:01:24 --> 00:01:29 actually stay put. So he asked the question is the 21 00:01:29 --> 00:01:35 species diversity of plants in a living community related to the 22 00:01:35 --> 00:01:41 productivity of that community, and also the resistance and the 23 00:01:41 --> 00:01:48 resilience of that community to stress? So what he did is he set up 24 00:01:48 --> 00:01:54 plots. And he went through generations of graduate students 25 00:01:54 --> 00:02:00 monitoring these over many years. This would be a plot that would 26 00:02:00 --> 00:02:06 have a single species in the plot. And here's a plot that has 24 27 00:02:06 --> 00:02:10 different species in the plot. If we mixed them together they were 28 00:02:10 --> 00:02:15 all indigenous species that would grow there. And he showed first 29 00:02:15 --> 00:02:19 that the total plant cover here as a percent was a function of the number 30 00:02:19 --> 00:02:24 of species per plot. So establishing that indeed 31 00:02:24 --> 00:02:28 productivity, the amount of plant biomass produced was a function of 32 00:02:28 --> 00:02:33 species diversity. And when you think about this it 33 00:02:33 --> 00:02:39 makes sense because the more diverse species you have the more likely 34 00:02:39 --> 00:02:45 they're able to exploit the full suite of resources in the soil and 35 00:02:45 --> 00:02:50 are probably more resistant to predation. So the more diverse the 36 00:02:50 --> 00:02:56 plot it has a greater biomass. The next thing he looked at, and 37 00:02:56 --> 00:03:02 this is in your textbook, was the effect of the biomass to the 38 00:03:02 --> 00:03:08 resistance to disturbance. So this is a change in biomass one 39 00:03:08 --> 00:03:14 year before a drought and then to the peak of the drought showing that 40 00:03:14 --> 00:03:20 this ratio increased with the number of species. And finally the 41 00:03:20 --> 00:03:26 resilience, that is how long it takes for the community to recover 42 00:03:26 --> 00:03:32 after it's been stressed, he was also able to show increase as 43 00:03:32 --> 00:03:37 the number of species increased. So there is a relationship between 44 00:03:37 --> 00:03:43 community structure, and indeed productivity, 45 00:03:43 --> 00:03:48 resistance and resilience increase if there is more diversity, 46 00:03:48 --> 00:03:54 which is, of course, one of the motivators for preserving species 47 00:03:54 --> 00:04:00 diversity on the planet globally. OK. 48 00:04:00 --> 00:04:05 Now we're going to try to tie all this together through this story. 49 00:04:05 --> 00:04:10 Now, going back, many of the slides that I'm going to show you you've 50 00:04:10 --> 00:04:15 already seen. Parts of this story you've already learned from my 51 00:04:15 --> 00:04:21 previous lectures, so I'm trying to tie this together 52 00:04:21 --> 00:04:26 and remind what you know and help you to think about how you can apply 53 00:04:26 --> 00:04:32 what you know to current issues in global ecology. 54 00:04:32 --> 00:04:39 So you remember this, our global carbon cycle showing the 55 00:04:39 --> 00:04:46 photosynthesis of the plants balanced by the respiration of the 56 00:04:46 --> 00:04:53 plants and the animals. You learned this. And superimposed 57 00:04:53 --> 00:05:00 on that is our burning of fossil fuels and land use changes, 58 00:05:00 --> 00:05:08 i.e., cutting down trees increasing CO2 in the atmosphere. 59 00:05:08 --> 00:05:13 And as we showed last time, I mean in the first set of lectures 60 00:05:13 --> 00:05:19 that this sudden excavation of this fossil photosynthate is causing a 61 00:05:19 --> 00:05:24 dramatic increase in CO2 in the atmosphere relative to historical 62 00:05:24 --> 00:05:30 concentrations of CO2. This is thousands of years before 63 00:05:30 --> 00:05:35 present. And we're worried about that. 64 00:05:35 --> 00:05:39 This is all reminding you, getting you in the train of thought here. 65 00:05:39 --> 00:05:44 We're worried about that because there's good evidence that these 66 00:05:44 --> 00:05:48 increases in CO2 are already increasing the temperature of the 67 00:05:48 --> 00:05:53 planet. This is average temperature over the last thousand years. 68 00:05:53 --> 00:05:57 And if it isn't already there is certainty that it will in 69 00:05:57 --> 00:06:02 the very near future. So let's look here in the ocean, 70 00:06:02 --> 00:06:07 my favorite ecosystem, where the phytoplankton, 71 00:06:07 --> 00:06:11 that you know all about now, play a critical role in drawing CO2 72 00:06:11 --> 00:06:16 out of the atmosphere. And this draw down is referred to 73 00:06:16 --> 00:06:21 as the “biological pump” of the oceans. And we talked about this 74 00:06:21 --> 00:06:26 very briefly. Here's the phytoplankton community 75 00:06:26 --> 00:06:31 photosynthesizing, drawing CO2 into the surface ocean. 76 00:06:31 --> 00:06:36 And then because of the food web, that you've learned all about, most 77 00:06:36 --> 00:06:41 of this phytoplankton productivity is eaten by zooplankton and by fish 78 00:06:41 --> 00:06:46 going through the marine food web. As it's eaten they are respiring 79 00:06:46 --> 00:06:52 and CO2 is released and it goes right out of the system. 80 00:06:52 --> 00:06:57 So CO2 in, CO2 out. But some of that carbon, some of that 81 00:06:57 --> 00:07:02 photosynthetic product finds its way to the deep ocean through fecal 82 00:07:02 --> 00:07:07 pellets of zooplankton, through aggregates of dead cells, 83 00:07:07 --> 00:07:13 through just basic mucus that fluffs off of jellyfish. 84 00:07:13 --> 00:07:16 It's all carbon that came from photosynthesis, 85 00:07:16 --> 00:07:19 but some of it settles down to the deep ocean where it's chewed upon. 86 00:07:19 --> 00:07:23 Now, here is where all those deep consumers that I showed you in the 87 00:07:23 --> 00:07:28 DVDs last time are. There are fish and squid and 88 00:07:28 --> 00:07:34 jellyfish in the deep oceans that feed on this carbon that rains down, 89 00:07:34 --> 00:07:40 because there is no photosynthesis down there, and bacteria that then 90 00:07:40 --> 00:07:46 regenerates that organic carbon into CO2. So this functions as a pump. 91 00:07:46 --> 00:07:52 And the concentration of carbon dioxide in the deep ocean is very 92 00:07:52 --> 00:07:59 high if you look at a depth profile of CO2. 93 00:07:59 --> 00:08:03 This is depth and this is CO2. And at the surface, of course, 94 00:08:03 --> 00:08:08 it's in equilibrium with the atmosphere. And it's very high in 95 00:08:08 --> 00:08:13 the deep ocean because at low temperatures and pressures it can 96 00:08:13 --> 00:08:18 hold. So this is a huge reservoir of CO2, so much that if you did a 97 00:08:18 --> 00:08:23 thought experiment and you killed all the life in the oceans and just 98 00:08:23 --> 00:08:28 shut off this biological pump and then you let the oceans mix all the 99 00:08:28 --> 00:08:33 way to the bottom, which they won't do, 100 00:08:33 --> 00:08:38 but this is just a thought experiment. 101 00:08:38 --> 00:08:42 And you let that all equilibrate with the atmosphere, 102 00:08:42 --> 00:08:47 all of that CO2, the concentration in the atmosphere would double to 103 00:08:47 --> 00:08:51 triple what it is today. That's how much CO2 is in the deep 104 00:08:51 --> 00:08:56 ocean. And so this is a natural function of the ocean ecosystem, 105 00:08:56 --> 00:09:01 is to maintain this pump and maintain this gradient of CO2. 106 00:09:01 --> 00:09:05 So this you also learned, remember? That the oceans are not 107 00:09:05 --> 00:09:10 this homogeneous soup of phytoplankton, 108 00:09:10 --> 00:09:15 but there are areas of very high phytoplankton biomass and 109 00:09:15 --> 00:09:20 productivity and low biomass and medium in the green here. 110 00:09:20 --> 00:09:25 And we talked about nutrient limitation of that primary 111 00:09:25 --> 00:09:30 production, which is the availability of nutrients. 112 00:09:30 --> 00:09:34 And what I told you was that the sort of standard understanding of 113 00:09:34 --> 00:09:39 this system was that nitrogen and phosphorus were the primary limiting 114 00:09:39 --> 00:09:43 nutrients, this is all review for your final exam, 115 00:09:43 --> 00:09:48 in aquatic ecosystems. But I told you that I was going to 116 00:09:48 --> 00:09:52 tell you in the last lecture that there was more to it than that. 117 00:09:52 --> 00:09:57 And there is indeed much more to it than that. 118 00:09:57 --> 00:10:01 So for years we thought that nitrogen and phosphorus were the 119 00:10:01 --> 00:10:06 nutrients that were regulating this differential productivity, 120 00:10:06 --> 00:10:10 but we knew that something was wrong with our understanding. 121 00:10:10 --> 00:10:15 Because these satellite images, which I just showed you, of the 122 00:10:15 --> 00:10:19 distribution of productivity showed this distribution. 123 00:10:19 --> 00:10:24 But if you took a simulation model and modeled the global productivity 124 00:10:24 --> 00:10:28 based on the availability of nitrogen and phosphorus to the 125 00:10:28 --> 00:10:33 phytoplankton this is what the model showed. 126 00:10:33 --> 00:10:37 They said this is what the ocean should look like, 127 00:10:37 --> 00:10:41 not that. There should be much more productivity here in the equator and 128 00:10:41 --> 00:10:45 down here in the Southern Ocean than there actually is. 129 00:10:45 --> 00:10:49 And, in fact, people wrote papers why isn't the equator greener? 130 00:10:49 --> 00:10:53 And they had all these different hypothesis for why that might be, 131 00:10:53 --> 00:10:57 a lot of them having to do with grazing with the food web. 132 00:10:57 --> 00:11:02 Well, it turns out that iron is a really important limiting factor in 133 00:11:02 --> 00:11:08 the ocean. And this is a story that has just unfolded in the last 15 134 00:11:08 --> 00:11:13 years. And I'm not telling you in exactly the order that it unfolded, 135 00:11:13 --> 00:11:19 but more or less in the order that it unfolded. A fellow named John 136 00:11:19 --> 00:11:25 Martin who is an oceanographer out at Moss Landing Marine Labs had been 137 00:11:25 --> 00:11:31 studying iron for quite a long time in the ocean. 138 00:11:31 --> 00:11:35 And he had a hypothesis that iron was limiting. But most people 139 00:11:35 --> 00:11:39 wouldn't believe him because most people, when they went out to 140 00:11:39 --> 00:11:44 measure iron in the oceans, got very high concentrations. 141 00:11:44 --> 00:11:48 So they said how could that be limiting? Well, 142 00:11:48 --> 00:11:53 it turned out that most people were measuring contamination in their 143 00:11:53 --> 00:11:57 iron samples. And if any of you have ever been on a marine ship, 144 00:11:57 --> 00:12:02 if you look around the deck you notice there is always rust. 145 00:12:02 --> 00:12:06 They are constantly painting marine ships, right, because the seawater 146 00:12:06 --> 00:12:11 is very corrosive. And so there is rust everywhere. 147 00:12:11 --> 00:12:16 And it turns out that you have to be heroically clean in order to 148 00:12:16 --> 00:12:21 measure the concentration of iron in seawater. And John Martin and his 149 00:12:21 --> 00:12:26 group realized this and went out and developed these techniques to 150 00:12:26 --> 00:12:31 collect the sample and to have it never see air before it went into 151 00:12:31 --> 00:12:36 the sample bottle. And they acid washed the sample 152 00:12:36 --> 00:12:40 bottles through this process which takes weeks and weeks and weeks. 153 00:12:40 --> 00:12:44 I mean you had to really believe that iron was limiting in order to 154 00:12:44 --> 00:12:48 go through all this agony to measure the level. So his group was able to 155 00:12:48 --> 00:12:52 measure really low levels of iron in seawater, but still they weren't 156 00:12:52 --> 00:12:56 able to convince people because this was such a totally different way of 157 00:12:56 --> 00:13:00 thinking about the oceans. So there was a lot of pushback. 158 00:13:00 --> 00:13:04 He also argued that iron is introduced to the oceans through 159 00:13:04 --> 00:13:09 atmospheric dust. Those people did believe. 160 00:13:09 --> 00:13:13 And that if you looked at the atmospheric dust flux, 161 00:13:13 --> 00:13:18 which is proportional to the iron flux, you'd see that in the Atlantic 162 00:13:18 --> 00:13:23 it is relatively high because you have wind patterns coming off these 163 00:13:23 --> 00:13:27 deserts in Africa. And also over here in the Western 164 00:13:27 --> 00:13:32 Pacific it's relatively high. It's low down here around the 165 00:13:32 --> 00:13:37 Antarctic because there's no land source there. So these patterns of 166 00:13:37 --> 00:13:43 dust delivery map on pretty well to this discrepancy to what we see and 167 00:13:43 --> 00:13:48 what we model if nitrogen was the limiting nutrient. 168 00:13:48 --> 00:13:53 So what John Martin argued was that there was lots of nitrogen and 169 00:13:53 --> 00:13:58 phosphorus in these regions but there's not enough iron for the 170 00:13:58 --> 00:14:04 phytoplanktons to actually utilize that. 171 00:14:04 --> 00:14:08 Remember the Redfield ratio we talked about, how it's the 172 00:14:08 --> 00:14:13 availability of nutrients relative to what's required by the plant that 173 00:14:13 --> 00:14:18 determines what's limiting? So he did some experiments where he 174 00:14:18 --> 00:14:23 went out in the boat and took samples. In the control sample he 175 00:14:23 --> 00:14:28 would add nothing and another sample he would phosphorus and nitrogen and 176 00:14:28 --> 00:14:33 another sample would add iron. And he was able to show that the 177 00:14:33 --> 00:14:37 addition of iron caused phytoplankton to bloom. 178 00:14:37 --> 00:14:41 He said iron is limiting in these regions of the ocean, 179 00:14:41 --> 00:14:46 but everybody said bah, bah, bah, no it's not, we don't 180 00:14:46 --> 00:14:50 believe you. They made up reasons why these experiments couldn't be 181 00:14:50 --> 00:14:54 true. There are not zooplankton in the bottle so this and that and the 182 00:14:54 --> 00:14:59 other thing. And so he persevered. And he said OK. 183 00:14:59 --> 00:15:04 If you don't believe my bottle experiment, I'm going to go out and 184 00:15:04 --> 00:15:10 I'm going to add iron to the ocean, then you'll believe me. So he said 185 00:15:10 --> 00:15:16 we're going to go out with a boat. And what they did was, and my lab 186 00:15:16 --> 00:15:22 was involved in these experiments. We had a small role, that's the 187 00:15:22 --> 00:15:28 boat, in measuring a certain component of the phytoplankton. 188 00:15:28 --> 00:15:32 But they pumped iron into the propeller wash of the boat and made 189 00:15:32 --> 00:15:37 a zigzag path in the ocean where there is about ten kilometers by ten 190 00:15:37 --> 00:15:42 kilometers. And the natural mixing in the surface ocean in about a day 191 00:15:42 --> 00:15:47 would mix that iron through that patch. And, of course, 192 00:15:47 --> 00:15:52 meanwhile the patch is moving. The oceans are moving, the patch is 193 00:15:52 --> 00:15:57 moving, they've got these location buoys, the captain of the ship is 194 00:15:57 --> 00:16:02 going crazy trying to navigate relative to these buoys rather than 195 00:16:02 --> 00:16:07 relative to the solid earth. But we were able to actually follow 196 00:16:07 --> 00:16:13 the patch. And, oh, here's John Martin who was also 197 00:16:13 --> 00:16:18 a friend of mine. And sadly enough he died of cancer 198 00:16:18 --> 00:16:24 before the first experiment showed unequivocally that iron is limiting. 199 00:16:24 --> 00:16:30 But he knew it was so that was good. Anyway, he threw out this line. 200 00:16:30 --> 00:16:34 “Give me a half a tanker of iron and I'll give you the next Ice Age. 201 00:16:34 --> 00:16:38 This was before the experiment because he was trying to drum up 202 00:16:38 --> 00:16:42 enthusiasm for the experiment because he wanted to do the science. 203 00:16:42 --> 00:16:46 But you see the connection here. So what's the connection between a 204 00:16:46 --> 00:16:53 tanker of iron and an Ice Age? 205 00:16:53 --> 00:16:57 Exactly. If you fertilize with iron, the phytoplankton photosynthesized 206 00:16:57 --> 00:17:02 more. It could be argued that they draw 207 00:17:02 --> 00:17:07 more CO2 out of the air and will cool the planet. 208 00:17:07 --> 00:17:12 OK, so he got a lot of attention because of that, 209 00:17:12 --> 00:17:16 even though this was a scientific experiment. So now I'm going to, 210 00:17:16 --> 00:17:21 and we'll come back to that, of course, later. 211 00:17:21 --> 00:17:26 I'm going to take you on an oceanographic cruise so you 212 00:17:26 --> 00:17:30 know what it's like. And this is one that my post-doc 213 00:17:30 --> 00:17:34 went on. This was not the first iron fertilization experiment. 214 00:17:34 --> 00:17:38 There have been about five of them now, but this was one of the 215 00:17:38 --> 00:17:42 actually one of the more recent ones that was done in the Southern Ocean. 216 00:17:42 --> 00:17:46 They've been done in the subArctic Pacific, in the Equatorial Pacific. 217 00:17:46 --> 00:17:50 I went on the one in the Equatorial Pacific because I'm a cruising 218 00:17:50 --> 00:17:54 light-weight, but my post-doc went on the one in the Southern Ocean and 219 00:17:54 --> 00:17:58 that's where these slides come from. But just to show you what goes into 220 00:17:58 --> 00:18:02 doing this. These are the vats where they mixed 221 00:18:02 --> 00:18:06 the iron which they mixed with an acid solution. 222 00:18:06 --> 00:18:11 And they also put in sulfur hexafluoride which is an inert 223 00:18:11 --> 00:18:15 tracer so they can use that to trace the patch. Here's the oceanographic 224 00:18:15 --> 00:18:20 ship. What you do when you launch a cruise is you patch things in these 225 00:18:20 --> 00:18:24 vans. And sometimes you have your whole lab in your van. 226 00:18:24 --> 00:18:29 And, in fact, for this trace metal clean work they have special trace 227 00:18:29 --> 00:18:33 metal clean vans where they're all Teflon lined and positive air 228 00:18:33 --> 00:18:38 pressure and all of that. So you ship this out to the 229 00:18:38 --> 00:18:42 Antarctic, and it gets loaded onto the ship, the van, 230 00:18:42 --> 00:18:46 and then gets tied down. This is what the lab looks like 231 00:18:46 --> 00:18:51 before the scientists arrive. It's just a bunch of tables that 232 00:18:51 --> 00:18:55 are tied. And these labs get broken down and rebuilt for each cruise 233 00:18:55 --> 00:19:00 because different types of scientists have different needs. 234 00:19:00 --> 00:19:04 And this is what it looks like when everybody is settled in. 235 00:19:04 --> 00:19:09 It's a very crude makeshift thing very crowded with equipment and 236 00:19:09 --> 00:19:13 wires and is all set up temporarily for a month's worth of work. 237 00:19:13 --> 00:19:18 So here's the shift leaving port. They're going out of New Zealand 238 00:19:18 --> 00:19:23 which is where most of these cruises leave from for the Antarctic. 239 00:19:23 --> 00:19:27 Here it is in the rough seas of the Southern Ocean. You cannot 240 00:19:27 --> 00:19:32 see this very well. But that's an iceberg which is a big 241 00:19:32 --> 00:19:38 problem down there, because that's just the tip of the 242 00:19:38 --> 00:19:44 iceberg. So navigation is very tricky. So here's a radar showing 243 00:19:44 --> 00:19:50 these icebergs scattered around that they have to look out for. 244 00:19:50 --> 00:19:56 Here's another one. Here's how the samples are taken. 245 00:19:56 --> 00:20:02 These little plastic PVC pipes are all electronically wired. 246 00:20:02 --> 00:20:06 And this ball, when they're open, 247 00:20:06 --> 00:20:10 is drawn into it. So when these are lowered in the water they fill up 248 00:20:10 --> 00:20:14 with water, and then you trigger it and the ball shuts it and then you 249 00:20:14 --> 00:20:18 bring it up. So you can set it, say this one goes off at 5 meters, 250 00:20:18 --> 00:20:22 that one 20, that one 50, that one 100, whatever. 251 00:20:22 --> 00:20:26 Wherever you want them you set them, and then it comes up and you have 252 00:20:26 --> 00:20:30 your water sample. Working in the Antarctic is 253 00:20:30 --> 00:20:34 particularly difficult. In this case this person is out 254 00:20:34 --> 00:20:38 there taking the snow off of these incubators that have sample water in 255 00:20:38 --> 00:20:42 bottles trying to make the phytoplankton think that they are 256 00:20:42 --> 00:20:46 still in the ocean, but they are in controlled 257 00:20:46 --> 00:20:50 experiments here. And they're taking the ice off so 258 00:20:50 --> 00:20:54 that the light intensity stays the same. And this is to summarize the 259 00:20:54 --> 00:20:58 results of the iron fertilization experiment just in a picture. 260 00:20:58 --> 00:21:02 This is the water without iron added and this is the water with iron 261 00:21:02 --> 00:21:07 added. The addition of iron to these waters causes major algal 262 00:21:07 --> 00:21:12 blooms. And here is just some of the data. We can just look at 263 00:21:12 --> 00:21:16 chlorophyll “a”, which you know is a measure of 264 00:21:16 --> 00:21:21 phytoplankton biomass in the patch versus outside of the patch. 265 00:21:21 --> 00:21:26 And this is actually a satellite image taken off of the NASA 266 00:21:26 --> 00:21:31 satellite of this iron-enriched patch. 267 00:21:31 --> 00:21:37 So there is no question now that the availability of iron limits primary 268 00:21:37 --> 00:21:43 productivity over vast regions of the ocean. I didn't think I was 269 00:21:43 --> 00:21:50 going to use the board but I will use the board. 270 00:21:50 --> 00:21:56 And because the Redfield ratio, which you guys now know, of carbon, 271 00:21:56 --> 00:22:04 some nitrogen, some phosphorus. Remember? We talked about this, 272 00:22:04 --> 00:22:13 106:16:1. If we add iron to this, iron is about 0.005. Anyway, tiny 273 00:22:13 --> 00:22:22 amounts of iron are required relative to nitrogen and phosphorus 274 00:22:22 --> 00:22:31 in order for a phytoplankton cell to grow. 275 00:22:31 --> 00:22:35 So you can leverage, if there's abundance of nitrogen and 276 00:22:35 --> 00:22:40 phosphorus, it just takes a little bit of iron to get this big bloom. 277 00:22:40 --> 00:22:44 And that was very appealing to people. Any time it takes a little 278 00:22:44 --> 00:22:49 bit of something to get a lot of something, I think people get 279 00:22:49 --> 00:22:53 interested. And I think what motivated this whole interest in 280 00:22:53 --> 00:22:58 ocean fertilization, I think, is motivated subconsciously 281 00:22:58 --> 00:23:02 a lot by man's ability to manipulate a system so large with 282 00:23:02 --> 00:23:07 so little effort. But that's sort of a [subset? 283 00:23:07 --> 00:23:12 . So the success of these scientific experiments, 284 00:23:12 --> 00:23:16 were really just to go out there and understand what regulated 285 00:23:16 --> 00:23:21 productivity in the oceans, were picked up very rapidly by 286 00:23:21 --> 00:23:26 entrepreneurs. And the proposal that was put 287 00:23:26 --> 00:23:31 forward was to develop a commercial ocean fertilization industry where 288 00:23:31 --> 00:23:36 you'd fertilize the surface oceans with iron. 289 00:23:36 --> 00:23:40 And I'm kind of joking here that money comes out the bottom, 290 00:23:40 --> 00:23:45 but I'll show you how this works in a minute. And turn this into a 291 00:23:45 --> 00:23:50 business. And there are a lot of unknown questions here. 292 00:23:50 --> 00:23:55 First the experiment showed that you could increase the phytoplankton 293 00:23:55 --> 00:24:00 growth here, but they didn't show that you could increase this export 294 00:24:00 --> 00:24:05 because the timescale of this is much longer than you can stay out on 295 00:24:05 --> 00:24:10 a ship to follow it. So it could be that this is 296 00:24:10 --> 00:24:15 increased and then this arrow is increased and you have no net flux. 297 00:24:15 --> 00:24:20 There is a little data on this flux now, but it's not compelling yet. 298 00:24:20 --> 00:24:24 Then the next question is if this was an industry, 299 00:24:24 --> 00:24:29 could you actually verify how much carbon was exported, if 300 00:24:29 --> 00:24:33 it could be exported? And then the collateral effects, 301 00:24:33 --> 00:24:37 which we're going to talk about in a minute, could it be made profitable? 302 00:24:37 --> 00:24:41 And the biggest question is what would the unintended consequences be 303 00:24:41 --> 00:24:45 of such an intentional fertilization? And this is where you guys come in 304 00:24:45 --> 00:24:49 because you have learned in this class a lot of things that could 305 00:24:49 --> 00:24:53 help you assess what the unintended consequences are, 306 00:24:53 --> 00:24:57 and we're going to talk about that. But how could you make money doing 307 00:24:57 --> 00:25:01 this? And it depends on a lot of things. 308 00:25:01 --> 00:25:07 Right now you couldn't, but there are people depending on a future in 309 00:25:07 --> 00:25:13 which you could, and this is the way it works. 310 00:25:13 --> 00:25:18 There is an emerging market in carbon trading credits, 311 00:25:18 --> 00:25:24 especially for countries that did sign the Kyoto Accord where there's 312 00:25:24 --> 00:25:30 a commitment to reducing CO2 emissions. 313 00:25:30 --> 00:25:34 And so these carbon offset credits are worth money. 314 00:25:34 --> 00:25:39 So the way this would work is, if it works, was you'd have this 315 00:25:39 --> 00:25:44 industry, you'd fertilize with iron, you'd be able to claim that you 316 00:25:44 --> 00:25:48 buried X amount of carbon in the deep ocean. And with that claim 317 00:25:48 --> 00:25:53 that would give you these carbon offset credits that are worth money. 318 00:25:53 --> 00:25:58 Utilities companies could then buy those, and if there was a cap on how 319 00:25:58 --> 00:26:03 much carbon emissions they could have this would increase their cap. 320 00:26:03 --> 00:26:07 So it's just like, you've probably heard about tree 321 00:26:07 --> 00:26:11 plantations generating carbon offset credits. And that's a going 322 00:26:11 --> 00:26:15 industry now. So that's how it would work. And there are companies, 323 00:26:15 --> 00:26:20 these are some websites. Planktos.com, they have patents 324 00:26:20 --> 00:26:24 filed on this process. How they're able to do that is 325 00:26:24 --> 00:26:28 beyond me since it's published in the open literature, 326 00:26:28 --> 00:26:33 in the scientific literature, but they do. 327 00:26:33 --> 00:26:37 Their mission is to develop formulations to [manage? 328 00:26:37 --> 00:26:42 phytoplankton productivity in carbon export. 329 00:26:42 --> 00:26:46 There's another one that you don't have in your slides. 330 00:26:46 --> 00:26:51 I just slipped this in this morning. But here's the website, 331 00:26:51 --> 00:26:55 Green Sea Venture, if you're interested. But it's another 332 00:26:55 --> 00:27:00 company that is marketing this idea. 333 00:27:00 --> 00:27:05 And here's another. I just saw this ad last month in 334 00:27:05 --> 00:27:10 [EOS?] which is a publication of the American Geophysical Union. 335 00:27:10 --> 00:27:15 And it seeks professionals to work on an ocean nourishment 336 00:27:15 --> 00:27:20 demonstration. This is a new word. 337 00:27:20 --> 00:27:25 The oceans need to be “nourished”. So there's a psychology here. 338 00:27:25 --> 00:27:30 They'll talk about ocean deserts that are nutrient poor, 339 00:27:30 --> 00:27:35 need to be nourished. And this is not only for 340 00:27:35 --> 00:27:40 sequestering CO2, but the claim is to increase wild 341 00:27:40 --> 00:27:45 fish stocks by fertilization. And so some of these outfits are 342 00:27:45 --> 00:27:50 really on the edge of credibility, and I will let you figure that out 343 00:27:50 --> 00:27:55 yourselves. If you did enough research you could find out. 344 00:27:55 --> 00:28:00 That's not part of your assignment for the class. 345 00:28:00 --> 00:28:05 But some of them are actually really rational-thinking scientists and 346 00:28:05 --> 00:28:10 engineers behind them. So there's a whole spectrum of 347 00:28:10 --> 00:28:15 people interested in this. So why am I concerned about it? 348 00:28:15 --> 00:28:21 In fact, one of my good friends, who is a very good scientist, really 349 00:28:21 --> 00:28:26 thinks we should explore the idea of fertilizing the Southern Oceans to 350 00:28:26 --> 00:28:31 bring the whales back. Because he thinks that the whales 351 00:28:31 --> 00:28:35 are gone because the krill are gone, the krill are gone because the 352 00:28:35 --> 00:28:39 phytoplankton are gone and the phytoplankton are gone because the 353 00:28:39 --> 00:28:43 whales aren't there to recycle the iron. And we don't know any of that, 354 00:28:43 --> 00:28:48 but that's the hypothesis. He thinks the ecosystem needs to be 355 00:28:48 --> 00:28:52 “jumpstarted” by an iron fertilization. 356 00:28:52 --> 00:28:56 So just to give you an idea the way people are starting to think about 357 00:28:56 --> 00:29:01 ecosystems and our ability to manipulate them. 358 00:29:01 --> 00:29:05 So why am I worried about this? And why should you be worried? 359 00:29:05 --> 00:29:10 Because you know now from taking this class that it's not that simple, 360 00:29:10 --> 00:29:15 that ecosystems are complex. And you know that if you fertilize 361 00:29:15 --> 00:29:20 with iron and you create a lot of organic carbon, 362 00:29:20 --> 00:29:25 phytoplankton, and some of that settles, a lot of that settles down 363 00:29:25 --> 00:29:30 to the deep ocean where there is no productivity, if it's consumed and 364 00:29:30 --> 00:29:35 digested by bacteria oxygen is going to be consumed, right? 365 00:29:35 --> 00:29:39 And respiration, heterotrophic bacteria, 366 00:29:39 --> 00:29:43 that's what you learned in the first set of lectures, 367 00:29:43 --> 00:29:47 oxygen will be consumed and CO2 will be regenerated. 368 00:29:47 --> 00:29:51 But if you have enough of this it will actually, 369 00:29:51 --> 00:29:55 the oxygen in the deep ocean waters will decrease and can even go anoxic 370 00:29:55 --> 00:30:00 if you do it long enough. And when you change -- 371 00:30:00 --> 00:30:04 That's the function of the system, the oxygen concentration. You 372 00:30:04 --> 00:30:08 change the community structure of the system and you'll have a 373 00:30:08 --> 00:30:12 different assemblage of microbes there than you had before. 374 00:30:12 --> 00:30:17 And one of the things that could happen, for example, 375 00:30:17 --> 00:30:21 is that you would increase the ammonia concentration by this 376 00:30:21 --> 00:30:25 reminerialization, you could stimulate nitrification 377 00:30:25 --> 00:30:29 and denitrification, which you learned about in my second 378 00:30:29 --> 00:30:34 lecture, I think. And you remember that a byproduct of 379 00:30:34 --> 00:30:38 that is nitrous oxide. And nitrous oxide is also a 380 00:30:38 --> 00:30:42 greenhouse gas that is 300 times more effective molecule per molecule 381 00:30:42 --> 00:30:46 than CO2. In terms of its greenhouse capability, 382 00:30:46 --> 00:30:50 in terms of its absorption of heat. So you're doing this whole thing to 383 00:30:50 --> 00:30:54 suck CO2 out of the atmosphere, but if a side effect is creating 384 00:30:54 --> 00:30:58 nitrous oxide, the amounts of which are impossible 385 00:30:58 --> 00:31:02 to predict at this point, you could be worse off than you 386 00:31:02 --> 00:31:06 started. And none of these proposals takes 387 00:31:06 --> 00:31:11 this downstream effect into account. The other thing that can happen in 388 00:31:11 --> 00:31:16 low oxygen waters is the stimulation of methanogenic bacteria which 389 00:31:16 --> 00:31:21 produce methane that is 22 times more effective molecule per molecule 390 00:31:21 --> 00:31:26 CO2 as a greenhouse gas. So there are ecosystem consequences 391 00:31:26 --> 00:31:31 to this. You cannot just say I'm going to add 392 00:31:31 --> 00:31:35 this and make carbon and that's the end of it, because you make carbon 393 00:31:35 --> 00:31:40 and things happen to that carbon. The other thing that is overlooked 394 00:31:40 --> 00:31:44 that you guys know about, remember this diagram of global 395 00:31:44 --> 00:31:48 ocean circulation? If you fertilize the Southern Ocean 396 00:31:48 --> 00:31:53 with iron and utilize the nitrogen and phosphorus here, 397 00:31:53 --> 00:31:57 when those waters upwell over here along the equation that nitrogen and 398 00:31:57 --> 00:32:02 phosphorus isn't in them. Now, that nitrogen and phosphorus is 399 00:32:02 --> 00:32:06 fueling the productivity of these ecosystems upon which fisheries are 400 00:32:06 --> 00:32:11 based. People are fishing the fish from those systems. 401 00:32:11 --> 00:32:15 So those people should be able to say to these people, 402 00:32:15 --> 00:32:19 hey, you took my nitrogen and phosphorus. That has to be factored 403 00:32:19 --> 00:32:24 into your balance sheet. My loss of fish, my loss of income 404 00:32:24 --> 00:32:28 from the fish needs to be factored into your balance sheet for 405 00:32:28 --> 00:32:33 your carbon credit. And if you do that the profitability 406 00:32:33 --> 00:32:39 is really marginal. Finally, there are models from a 407 00:32:39 --> 00:32:44 group at Princeton that show if you do this in a sustained way that 408 00:32:44 --> 00:32:50 after many, many years, this is 1500 which is the extreme, 409 00:32:50 --> 00:32:55 but even after 100 years you create, this is latitude. Here's the 410 00:32:55 --> 00:33:01 equator 40 degrees, 40 degrees south. 411 00:33:01 --> 00:33:06 So this is a broad swath of the ocean and this is depth, 412 00:33:06 --> 00:33:11 OK? So this shows a huge, huge anoxic zone in the oceans that 413 00:33:11 --> 00:33:16 would be causes by sustained fertilization in this way. 414 00:33:16 --> 00:33:22 Not surprising, you're making a lot of organic carbon. 415 00:33:22 --> 00:33:27 It's going to be consumed by bacteria. So that is all a story, 416 00:33:27 --> 00:33:32 a scenario to get you thinking about your future and your relationship 417 00:33:32 --> 00:33:38 with the earth's ecosystems in the future. 418 00:33:38 --> 00:33:42 Because our relationship with these systems is changing dramatically. 419 00:33:42 --> 00:33:46 We are now in charge. We've been in charge for a while, 420 00:33:46 --> 00:33:50 but we haven't taken the responsibility of being in charge 421 00:33:50 --> 00:33:54 for a while of these systems. And your generation is going to be 422 00:33:54 --> 00:33:59 making these kinds of decisions. As we move forward and we experience 423 00:33:59 --> 00:34:04 the aftermath of some of the manipulations we've done in the past 424 00:34:04 --> 00:34:09 like burning fossil fuels and increasing CO2 in the atmosphere 425 00:34:09 --> 00:34:13 there will be choices to make. Do we just adapt to this global 426 00:34:13 --> 00:34:18 warming or do we know enough about how the earth works to try to 427 00:34:18 --> 00:34:23 counteract it in ways like fertilizing the oceans. 428 00:34:23 --> 00:34:28 And then you'll have to decide are the risks of fertilizing the oceans 429 00:34:28 --> 00:34:33 much greater than the risks of adapting to climate change? 430 00:34:33 --> 00:34:38 And a new trend in thinking about the earth is thinking about nature 431 00:34:38 --> 00:34:43 and ecosystems as not simply as something that we value because 432 00:34:43 --> 00:34:49 they're part of our world and we should set up reserves so that we 433 00:34:49 --> 00:34:54 can enjoy them and see nature and so generations in the future will know 434 00:34:54 --> 00:34:59 what natural ecosystems look like, but starting to think of ecosystems 435 00:34:59 --> 00:35:05 as things that provide services for humans and actually have a monetary 436 00:35:05 --> 00:35:10 value that is not part of our economy, it's not part of our 437 00:35:10 --> 00:35:16 economic system but they provide functions to our world for free. 438 00:35:16 --> 00:35:20 And so as we destroy them we're losing those functions. 439 00:35:20 --> 00:35:25 And this is a very well known paper. There's a journal called Ecological 440 00:35:25 --> 00:35:29 Economics that tries to talk about factoring in ecosystems 441 00:35:29 --> 00:35:35 into our economy. And this is a very well known paper 442 00:35:35 --> 00:35:41 on the value of the world's ecosystem services and natural 443 00:35:41 --> 00:35:47 capital. And course this is impossible to do but you've got to 444 00:35:47 --> 00:35:53 try. So they evaluated the ecosystem services as worth $33 445 00:35:53 --> 00:35:59 trillion. And this is just a brief list of some of the services that 446 00:35:59 --> 00:36:04 they analyze in this. One that's pretty easy to wrap your 447 00:36:04 --> 00:36:08 brain around is the pollination of crops by insects. 448 00:36:08 --> 00:36:13 We rely on insects to pollinate crops. They do it for free and we 449 00:36:13 --> 00:36:18 rely on that. And just this is estimated to be worth $6 billion. 450 00:36:18 --> 00:36:22 That if you had to hire somebody to manually pollinate your crops if 451 00:36:22 --> 00:36:27 there were no bees and all of the things that are doing it, 452 00:36:27 --> 00:36:32 it would cost $6 billion globally. There is decomposition of waste, 453 00:36:32 --> 00:36:38 recycling nutrients, dispersion of seeds, control of pests, 454 00:36:38 --> 00:36:43 purification of the air and water, ecosystems to do this. And this is 455 00:36:43 --> 00:36:49 compared to the GNP of $18 trillion per year, the global gross national 456 00:36:49 --> 00:36:54 product. So this is sort of a shift in our thinking about how we think 457 00:36:54 --> 00:37:00 about ecosystems. And just in the last -- 458 00:37:00 --> 00:37:04 This slide was in one of your handouts about, 459 00:37:04 --> 00:37:08 I don't know, five lectures ago, but I didn't get to it so I thought 460 00:37:08 --> 00:37:13 I would bring it in now. Just in the last, well, April 14th 461 00:37:13 --> 00:37:17 was announced this Millennium Ecosystem Assessment Report, 462 00:37:17 --> 00:37:21 which was over a thousand scientists worldwide assessing the state of the 463 00:37:21 --> 00:37:26 earth's global ecosystems and from the point of view of strengthening 464 00:37:26 --> 00:37:30 capacity to manage ecosystem's sustainability for 465 00:37:30 --> 00:37:35 human well-being. So the focus is on how do we manage 466 00:37:35 --> 00:37:39 these things for ourselves and the future generation? 467 00:37:39 --> 00:37:43 And you can go to the website if you want to get depressed. 468 00:37:43 --> 00:37:47 Well, you can get depressed about what we've done. 469 00:37:47 --> 00:37:52 But you can be optimistic that we're really facing up to this 470 00:37:52 --> 00:37:56 challenge in a very systematic way. But the bottom line is that 471 00:37:56 --> 00:38:00 two-thirds of the natural machinery of the earth has already been 472 00:38:00 --> 00:38:05 degraded by humans. And water use is dramatic. 473 00:38:05 --> 00:38:10 Major rivers are dry before they reach the oceans. 474 00:38:10 --> 00:38:15 We are mining groundwater basically. We're taking water out of the 475 00:38:15 --> 00:38:20 ground much faster than it's being recharged. One-quarter of all fish 476 00:38:20 --> 00:38:25 stocks are already over-harvested. I mean we're in a non-sustainable 477 00:38:25 --> 00:38:30 mode. I don't need to tell you. You read the newspaper and you know 478 00:38:30 --> 00:38:35 this, and so I'll skip over this. Oh, just this last part I think is 479 00:38:35 --> 00:38:39 the most important. The argument is that more and more 480 00:38:39 --> 00:38:43 people are going to be living in the cities in the future, 481 00:38:43 --> 00:38:47 so less and less in touch with nature. So nature is going to be 482 00:38:47 --> 00:38:52 more and more of an abstraction to us. And people are really worried 483 00:38:52 --> 00:38:56 about this because conservation of natural spaces is not just a luxury. 484 00:38:56 --> 00:39:00 This is a dangerous illusion that ignores our dependency 485 00:39:00 --> 00:39:05 on these systems. And we have to really strengthen 486 00:39:05 --> 00:39:09 that understanding. OK, so now I want to lead you, 487 00:39:09 --> 00:39:14 this slide several students have told me is the only thing they 488 00:39:14 --> 00:39:18 remember from this class and my other ecology class. 489 00:39:18 --> 00:39:23 And that makes me very happy. If this is the only thing you 490 00:39:23 --> 00:39:27 remember that's great because this is really the take-home message for 491 00:39:27 --> 00:39:32 you and your generation. And this is how we have changed our 492 00:39:32 --> 00:39:36 relationship to the earth and this is where we are right now. 493 00:39:36 --> 00:39:41 So you learned in the first lecture about the biosphere, 494 00:39:41 --> 00:39:46 autotrophs producing organic carbon, heterotrophs consuming organic 495 00:39:46 --> 00:39:50 carbon and with a little bit of input from the earth's crust, 496 00:39:50 --> 00:39:55 nitrogen and phosphorus, and this system running pretty well 497 00:39:55 --> 00:40:00 before humans. And before the Industrial Revolution 498 00:40:00 --> 00:40:04 societies fit into this system of tight recycling taking a little bit 499 00:40:04 --> 00:40:09 off of the autotrophic productivity and putting a little bit of waste 500 00:40:09 --> 00:40:14 into the system. But then we had the Industrial 501 00:40:14 --> 00:40:18 Revolution. We've cut down massive amounts of trees. 502 00:40:18 --> 00:40:23 we've changed the very landscape of the autotrophic system, 503 00:40:23 --> 00:40:28 and we've dramatically increased the waste stream. 504 00:40:28 --> 00:40:32 And we're mining the lithosphere in a huge way, elements, 505 00:40:32 --> 00:40:36 mining for metals and things used in manufacturing, 506 00:40:36 --> 00:40:40 etc., which is, of course, increasing this waste 507 00:40:40 --> 00:40:45 stream. So this is where we are now. And we know that this is not 508 00:40:45 --> 00:40:49 sustainable the way we're operating. So this is your generation's 509 00:40:49 --> 00:40:53 decision. Are you going to go this way or are you going to go that way? 510 00:40:53 --> 00:40:57 Very simple. You've got to point your compass in the 511 00:40:57 --> 00:41:02 right direction. So this way just increases these 512 00:41:02 --> 00:41:07 streams, the waste stream and the erosion of the natural ecosystems 513 00:41:07 --> 00:41:11 and the mining from the lithosphere. This stream works toward recycling 514 00:41:11 --> 00:41:16 within the societies that we've already built, 515 00:41:16 --> 00:41:21 restoring natural ecosystems so they can do their functions properly for 516 00:41:21 --> 00:41:26 cleaning air and water, and leaving enough productivity for 517 00:41:26 --> 00:41:31 the rest of the heterotrophs on land. 518 00:41:31 --> 00:41:35 You know we're not the only heterotrophs. There are all these 519 00:41:35 --> 00:41:40 other species that rely on this primary productivity, 520 00:41:40 --> 00:41:45 the birds and, well, all the species. So we need to leave some of that 521 00:41:45 --> 00:41:50 for them so the ecosystems can sustain themselves. 522 00:41:50 --> 00:41:55 And so this is where we should be. And we just need to find the will 523 00:41:55 --> 00:42:00 to get there. So easily said, not easily done. 524 00:42:00 --> 00:42:04 And there's an organization called The Natural Step. 525 00:42:04 --> 00:42:08 I put this website, which you might want to write down 526 00:42:08 --> 00:42:12 because I don't think this was on your slide, if you're interested you 527 00:42:12 --> 00:42:16 can write it down, that I think has a very, 528 00:42:16 --> 00:42:20 very creative approach to working with industry to try to direct 529 00:42:20 --> 00:42:24 things in the right direction and where they talk about the compass. 530 00:42:24 --> 00:42:28 And they say there are basic system conditions for sustainability that 531 00:42:28 --> 00:42:33 if we don't maintain we will be going in the wrong direction. 532 00:42:33 --> 00:42:37 And it's just a total no-brainer. It's very simple. Substances from 533 00:42:37 --> 00:42:41 the earth's crust must not systematically increase in nature. 534 00:42:41 --> 00:42:45 Obviously, that's not sustainable if you do that and substances 535 00:42:45 --> 00:42:49 produced by society must not systematically increase in nature. 536 00:42:49 --> 00:42:53 We cannot keep pouring waste into nature. The physical basis for the 537 00:42:53 --> 00:42:57 productivity and diversity of nature, i.e., the green part, 538 00:42:57 --> 00:43:02 the autotrophic cycle cannot be systematically deteriorated. 539 00:43:02 --> 00:43:06 And then they add to this we must be efficient enough to meet basic human 540 00:43:06 --> 00:43:11 needs. We have to work toward efficiency which is working toward 541 00:43:11 --> 00:43:16 tightening this recycling here. And they've been very effective in 542 00:43:16 --> 00:43:21 many countries in pointing industries in the right direction. 543 00:43:21 --> 00:43:25 Every time that they make a decision about what metal to use in 544 00:43:25 --> 00:43:30 a particular manufacturing process, they look at how much of that metal 545 00:43:30 --> 00:43:36 has already been mined. Is there an alternative metal that 546 00:43:36 --> 00:43:42 they could, etc. They're constantly using at this 547 00:43:42 --> 00:43:48 compass. OK. Obviously, the compass is not pointed in the 548 00:43:48 --> 00:43:54 right direction. A no-brainer. Building cars that 549 00:43:54 --> 00:44:00 use more fuel and get less miles per gallon is not the right direction. 550 00:44:00 --> 00:44:05 So some of these are very easy to answer. And I don't want to cast 551 00:44:05 --> 00:44:10 dispersion on SUVs, but in case you didn't recognize it 552 00:44:10 --> 00:44:16 that's what that is. I mean fuel efficiency is here, 553 00:44:16 --> 00:44:21 we can have it if we want to, and we need to work on that. 554 00:44:21 --> 00:44:27 And finally, well, this isn't finally. This is second to finally. 555 00:44:27 --> 00:44:32 I love this cartoon. This is the [doctor Saturn? 556 00:44:32 --> 00:44:36 or whatever looking at the earth and diagnosing our planet at this 557 00:44:36 --> 00:44:41 stage in its evolution. And finally I'll leave you with 558 00:44:41 --> 00:44:46 this image which is my favorite image of the earth because it has no 559 00:44:46 --> 00:44:50 national boundaries and it really does remind us that it's a living 560 00:44:50 --> 00:44:55 planet and that time is now. I mean, I know this sounds 561 00:44:55 --> 00:45:00 overdramatic but it's not. I mean we've changed this planet so 562 00:45:00 --> 00:45:04 much in the last 200 years relative to all the years before. 563 00:45:04 --> 00:45:09 And the next 50 years, your time to make a difference is absolutely 564 00:45:09 --> 00:45:13 critical, so I hope you guys will go off and save the planet for us. 565 00:45:13 --> 00:45:16 Have fun and have a great summer.