1 00:00:04,080 --> 00:00:07,000 This is Geology Bites with Oliver Strimpel. 2 00:00:08,840 --> 00:00:12,600 The Amazon basin is the most biodiverse region on Earth. 3 00:00:13,320 --> 00:00:18,000 It is the home of one in five of all bird species, one in five of 4 00:00:18,000 --> 00:00:22,160 all fish species, and over 40,000 plant species. 5 00:00:22,960 --> 00:00:27,480 How did this come to be? Can we answer this question just 6 00:00:27,480 --> 00:00:31,120 by looking at the present day climate, soil and other aspects 7 00:00:31,120 --> 00:00:34,000 of the environment? Or do we have to look at the 8 00:00:34,000 --> 00:00:38,440 region's history? Karina Horne has shown that we 9 00:00:38,440 --> 00:00:42,000 need to go back at least 23 million years to the early 10 00:00:42,000 --> 00:00:46,440 Miocene to consider two key geologically caused drivers of 11 00:00:46,440 --> 00:00:52,240 biodiversity, the rise of the Andes and marine incursions. 12 00:00:53,320 --> 00:00:56,920 She is an associate professor in the Institute for Biodiversity 13 00:00:56,920 --> 00:01:00,160 and Ecosystem Dynamics at the University of Amsterdam. 14 00:01:01,080 --> 00:01:03,560 Karina Horne, welcome to Geology Bites. 15 00:01:03,840 --> 00:01:05,400 Thank you very much for inviting me. 16 00:01:05,440 --> 00:01:07,680 It's a great honour to be part of this series. 17 00:01:08,320 --> 00:01:12,240 The Andes rose on the western shore of South America, while 18 00:01:12,240 --> 00:01:16,440 the Amazon basin lies far to the east, extending all the way to 19 00:01:16,440 --> 00:01:20,200 the Atlantic Coast. How can the rise of the Andes 20 00:01:20,240 --> 00:01:23,480 affect biodiversity on the other side of the continent? 21 00:01:23,760 --> 00:01:25,520 Yeah, that's an interesting point. 22 00:01:25,520 --> 00:01:30,000 We know from tectonic models and also from geophysical models 23 00:01:30,000 --> 00:01:33,000 that the central Arnors and the northern Arnors had a strong 24 00:01:33,000 --> 00:01:37,840 uplift in the Neogene and this affected the climate. 25 00:01:37,840 --> 00:01:42,000 It generated an orographic barrier and it also we have 26 00:01:42,000 --> 00:01:46,640 fermented erosion processes. So we see this effect of uplift 27 00:01:47,080 --> 00:01:49,600 in the Amazon basin. So because also there was 28 00:01:49,600 --> 00:01:52,800 another effect which was subsidence on the eastern flunks 29 00:01:52,800 --> 00:01:54,760 of the Andes. And so there was accommodation 30 00:01:54,760 --> 00:01:59,000 space for sediments to arrive. And those processes play a very 31 00:01:59,000 --> 00:02:03,240 important role in reshaping not only the landscape and the 32 00:02:03,240 --> 00:02:07,400 topography, but also creating a lot of geological changes and 33 00:02:07,400 --> 00:02:10,039 Palo environmental changes in the Amazon basin. 34 00:02:10,639 --> 00:02:14,480 And for that reason we have to see the history of the Amazon 35 00:02:14,720 --> 00:02:18,000 also in the context of the uplift history of the Anders. 36 00:02:18,440 --> 00:02:21,120 So let's talk a bit more about some of the aspects you 37 00:02:21,120 --> 00:02:24,000 mentioned. How does the increasing 38 00:02:24,160 --> 00:02:27,920 topography of the Andes affect the climate in the Amazon basin? 39 00:02:28,400 --> 00:02:31,240 If you think of the the central and northern Anders, now they're 40 00:02:31,240 --> 00:02:33,840 they're very important or a graphic barrier. 41 00:02:34,160 --> 00:02:37,880 So they're about 7000 meters in the highest peaks in Peru and 42 00:02:37,880 --> 00:02:41,840 6000 in the northern Anders. So this orographic barrier 43 00:02:41,840 --> 00:02:46,040 intercepts the intertropical convergence on these humid air 44 00:02:46,040 --> 00:02:48,160 masses that come from the Atlantic. 45 00:02:48,600 --> 00:02:51,520 And so they're intercepted and therefore the increased 46 00:02:51,520 --> 00:02:54,520 precipitation rates on the intercepting flunk of the arms 47 00:02:54,520 --> 00:02:56,840 and creating a rain shadow at the other side. 48 00:02:57,320 --> 00:03:00,400 And with that, they also generate, of course, erosion 49 00:03:00,440 --> 00:03:02,920 processes. And so this orographic barrier 50 00:03:02,920 --> 00:03:06,200 also creates therefore an elevation gradient and a 51 00:03:06,200 --> 00:03:09,840 climatic gradient. So we see that we have high 52 00:03:09,840 --> 00:03:13,640 precipitation and high temperatures at the lower flunk. 53 00:03:13,760 --> 00:03:18,240 And then as we go up the mountain, of course temperatures 54 00:03:18,240 --> 00:03:20,760 decrease. And especially at mid elevation, 55 00:03:20,760 --> 00:03:22,880 we have very high precipitation levels. 56 00:03:22,880 --> 00:03:25,520 And that generates the cloud forest, which is super rich. 57 00:03:25,880 --> 00:03:29,360 And we have the Alpine zone, which is much colder and more 58 00:03:29,360 --> 00:03:31,520 arid. And so we have already high 59 00:03:31,520 --> 00:03:34,320 diversity at the mountain flunks itself. 60 00:03:34,680 --> 00:03:38,640 But also this effect of intercepting the humidity also 61 00:03:38,640 --> 00:03:41,200 leads to increased precipitation in the western Amazon. 62 00:03:41,200 --> 00:03:44,480 So we see a differentiation between the eastern and the 63 00:03:44,480 --> 00:03:46,920 western Amazon. And there's also already a 64 00:03:46,920 --> 00:03:49,280 geological difference between, of course, having these 65 00:03:49,520 --> 00:03:53,600 mountains in the West and also the crat on the old crystalline 66 00:03:53,600 --> 00:03:57,880 lowlands in the eastern Amazon. So there's really a big division 67 00:03:57,880 --> 00:04:01,800 in terms of climate, but also in geology for the Amazon that is 68 00:04:01,800 --> 00:04:04,840 generated by the Onlean uplift. Let's talk a bit about the 69 00:04:04,840 --> 00:04:08,160 geology, because obviously the topography increases the rate of 70 00:04:08,160 --> 00:04:13,480 erosion and provides sediments that are carried by rivers into 71 00:04:13,480 --> 00:04:18,079 the Amazon basin. Are these sediments different 72 00:04:18,160 --> 00:04:20,880 from those that were already present in the Amazon at the 73 00:04:20,880 --> 00:04:23,440 time? Yeah, that's very interesting 74 00:04:23,440 --> 00:04:25,280 aspect. When you walk around or when you 75 00:04:25,320 --> 00:04:28,400 travel by boats along the rivers, there's a huge 76 00:04:28,400 --> 00:04:31,200 difference in the waters of the Amazon region. 77 00:04:31,200 --> 00:04:34,360 So you have the white water rivers which are derived from 78 00:04:34,360 --> 00:04:37,160 the Anders and you have the black water rivers, for 79 00:04:37,160 --> 00:04:40,040 instance, that are derived from the Craton or the Clearwater 80 00:04:40,040 --> 00:04:43,080 rivers that are derived from the other Highlands that you have in 81 00:04:43,080 --> 00:04:45,480 the in the Amazon. So the rivers on themselves 82 00:04:45,480 --> 00:04:48,880 already reveal a difference in sediment composition. 83 00:04:48,880 --> 00:04:53,360 And so the Eastern part of the Amazon dominated by the Kraton 84 00:04:53,480 --> 00:04:57,000 is weathered surfaces. It's a very weathered profile. 85 00:04:57,000 --> 00:05:02,360 So those are very stable in terms of composition and also 86 00:05:02,360 --> 00:05:05,760 depleted of nutrients. So they have a very distinct 87 00:05:05,840 --> 00:05:08,440 geochemical signature. So geochemists can 88 00:05:08,640 --> 00:05:11,400 differentiate. The sediments that are older 89 00:05:11,400 --> 00:05:15,760 than 1 1/2 billion are of Kraton and younger than 1 1/2 billion 90 00:05:15,760 --> 00:05:18,560 are Ambien. They also have characteristic 91 00:05:18,560 --> 00:05:21,680 heavy mineral composition if you were to look at that way, so 92 00:05:21,720 --> 00:05:25,720 stable minerals from the carotone and unstable minerals 93 00:05:25,720 --> 00:05:27,760 from the metamorphic rocks in the onus. 94 00:05:28,120 --> 00:05:32,840 So you can see that by measuring the chemistry of the sediments 95 00:05:32,840 --> 00:05:35,600 in outcrops and you see it in the rivers. 96 00:05:36,480 --> 00:05:40,480 And so when you travel around in the field, you see for instance 97 00:05:40,520 --> 00:05:44,200 also clays that are typically blue, very bright and have a 98 00:05:44,200 --> 00:05:47,160 very different composition of for for instance, these silici 99 00:05:47,160 --> 00:05:51,160 classic sediments, pure quartz and grey clays that are derived 100 00:05:51,160 --> 00:05:54,600 from the cratum. So the unders is like a big 101 00:05:54,600 --> 00:05:57,720 fertilizer of Amazon and western Atlantic. 102 00:05:58,040 --> 00:06:03,800 Where new ecosystems created specifically as a result of the 103 00:06:03,800 --> 00:06:07,920 Andes driven changes in climate and the riverborne sediments 104 00:06:07,920 --> 00:06:09,840 that you just talked about. Yeah. 105 00:06:09,840 --> 00:06:12,360 So there were big changes happening in the Amazon in 106 00:06:12,360 --> 00:06:16,480 relation to this onion uplift. So a lot of the changes are 107 00:06:16,480 --> 00:06:20,480 driven on one side by this particular geological 108 00:06:20,480 --> 00:06:24,480 configuration, by this changes in mantle convection. 109 00:06:24,480 --> 00:06:27,400 And due to this slop subduction that we learned from the 110 00:06:27,400 --> 00:06:29,720 geophysicists have played an important role. 111 00:06:30,080 --> 00:06:32,920 And so that has generated on one side the uplift, but on the 112 00:06:32,920 --> 00:06:36,960 other side the subsidence. And through that, we've had a 113 00:06:36,960 --> 00:06:41,120 very unique system there, which is this Fluviolac stream, but 114 00:06:41,120 --> 00:06:45,040 we'll call it the Pay Bass Mega Wetland that really transformed 115 00:06:45,040 --> 00:06:49,640 the environment and it extended over more than 1,000,000 square 116 00:06:49,640 --> 00:06:52,960 kilometres and it had a long existence, we think from the 117 00:06:52,960 --> 00:06:56,240 geological record that existed for almost 10 million years. 118 00:06:56,520 --> 00:07:00,800 Pay Bass, you said. Yes, it's called Paybas system 119 00:07:01,080 --> 00:07:05,440 based on the typical outcrop at Paybas, which is in Peru. 120 00:07:05,800 --> 00:07:09,400 It's an amazing setting because it seems it was like a cradle of 121 00:07:09,400 --> 00:07:12,360 spectation. So it opened up the opportunity 122 00:07:12,360 --> 00:07:17,480 for taxa that were not in the region that that settled there 123 00:07:17,480 --> 00:07:19,200 because of dispersal from elsewhere. 124 00:07:19,200 --> 00:07:21,440 And they found a suitable environment. 125 00:07:21,880 --> 00:07:24,800 And that applies to molluscs and ostracots. 126 00:07:25,120 --> 00:07:28,880 Ostracots, these tiny crustaceans and molluscs as 127 00:07:28,880 --> 00:07:31,920 well. They diversify very much in that 128 00:07:31,920 --> 00:07:34,080 system. And they created a complete new 129 00:07:34,080 --> 00:07:37,640 ecosystem that wasn't there. And of course it was all sort of 130 00:07:37,680 --> 00:07:40,440 other organisms related in this traffic chain. 131 00:07:40,440 --> 00:07:44,520 So it had a very big variety of reptiles, for instance, that 132 00:07:44,640 --> 00:07:46,680 were also able to feed on these mollusc. 133 00:07:46,680 --> 00:07:49,640 And there was a very diverse aquatic fauna. 134 00:07:50,120 --> 00:07:53,400 And in terms of vegetation, we know there was a diverse 135 00:07:53,400 --> 00:07:56,160 rainforest already in the periphery of the system, but 136 00:07:56,160 --> 00:08:00,240 also marshland swamps by palms that now are extinct. 137 00:08:01,000 --> 00:08:04,920 So that system existed because of these special geological 138 00:08:04,920 --> 00:08:08,680 circumstances were created, but after some time, it also 139 00:08:08,680 --> 00:08:11,760 disappeared. So at some point, because of 140 00:08:11,760 --> 00:08:15,320 this subduction process, there was a eastward tilt. 141 00:08:15,320 --> 00:08:19,320 The sedimentary basins in the western Amazon got overfilled 142 00:08:19,320 --> 00:08:23,240 and this system, this paper system that existed for so long, 143 00:08:23,240 --> 00:08:26,360 then transitioned into a flu field system into the 144 00:08:26,360 --> 00:08:30,160 transcontinental Amazon. And we know that from both the 145 00:08:30,360 --> 00:08:34,480 sedimentary record in the western Amazonian basins, but 146 00:08:34,480 --> 00:08:38,320 also from the marine basin in the Atlantic site where the 147 00:08:38,799 --> 00:08:42,960 Amazon River sediments arrive. And so from the western 148 00:08:42,960 --> 00:08:47,840 Amazonian basins, we know that this effect of the uplift of the 149 00:08:47,840 --> 00:08:51,280 unders started to be recorded in the Miocene. 150 00:08:51,400 --> 00:08:53,320 So we know about 60 million years. 151 00:08:53,320 --> 00:08:56,800 We see already that there is a high elevation unders because of 152 00:08:56,800 --> 00:09:00,760 the type of deposits we get. We get pollen and spores, which 153 00:09:00,760 --> 00:09:02,520 is the reproductive material of plants. 154 00:09:02,800 --> 00:09:06,760 We get them deposited in the sediment basin and they show us 155 00:09:06,760 --> 00:09:10,080 that there was a high montane vegetation in the unders at the 156 00:09:10,080 --> 00:09:13,120 time. And then we see in the marine 157 00:09:13,120 --> 00:09:17,120 record that we get sediments of Ambien origin. 158 00:09:17,240 --> 00:09:19,320 We get them around 10 million years. 159 00:09:19,600 --> 00:09:22,600 So we see how this system based on the sedimentary record on 160 00:09:22,600 --> 00:09:27,840 land, we see how this wetland disappears and we see the 161 00:09:27,840 --> 00:09:31,760 emergence of the Amazon River and we see the arrival of this 162 00:09:31,760 --> 00:09:34,440 river in the sediments of the marine record. 163 00:09:34,600 --> 00:09:36,200 So that's how we follow the story. 164 00:09:36,800 --> 00:09:42,320 We don't see a similar burgeoning of biodiversity next 165 00:09:42,320 --> 00:09:47,840 to newly formed mountain chains in all other locations, so there 166 00:09:47,840 --> 00:09:50,760 must have been other factors at play here as well. 167 00:09:51,280 --> 00:09:55,080 In my introduction, I also mentioned that marine incursions 168 00:09:55,080 --> 00:09:57,440 were an important driver of biodiversity. 169 00:09:57,960 --> 00:10:00,600 Is that part of what makes the Amazon different? 170 00:10:01,440 --> 00:10:04,320 Yeah, definitely. But we have to go back again to 171 00:10:04,320 --> 00:10:08,520 this complex geological history first, because it's in the 1st 172 00:10:08,520 --> 00:10:13,840 place, this subsidence that's triggered by the special mantle 173 00:10:13,840 --> 00:10:17,280 convection and the slop subduction that generates this 174 00:10:17,280 --> 00:10:20,480 opportunity for marine incursions to reach the area. 175 00:10:20,560 --> 00:10:26,280 But also, beside Andion uplift and flat slab subduction, the 176 00:10:26,280 --> 00:10:30,040 sea level rise caused by global warming during the early and 177 00:10:30,040 --> 00:10:33,240 middle Miocene help facilitate the marine incursions. 178 00:10:33,640 --> 00:10:36,680 For sure, that's a very important driver. 179 00:10:36,880 --> 00:10:40,680 And when at some point this process stopped and then marine 180 00:10:40,680 --> 00:10:42,720 incursions are no longer possible also because of 181 00:10:42,720 --> 00:10:46,480 blockages with the pathway which we think was from the Caribbean 182 00:10:46,480 --> 00:10:50,320 and maybe even from the Pacific. So it is in the 1st place driven 183 00:10:50,320 --> 00:10:53,960 by the geological processes. And then the marine incursions 184 00:10:53,960 --> 00:10:58,040 have a very important role in, well, also fertilizing the 185 00:10:58,040 --> 00:11:00,240 Western Amazon. But that is one thing. 186 00:11:00,240 --> 00:11:03,400 That's the geochemical aspect of bringing in new nutrients. 187 00:11:03,720 --> 00:11:07,120 But on the other side, it's also a very interesting aspect of the 188 00:11:07,160 --> 00:11:11,400 evolutionary history because we have all these organisms that 189 00:11:11,400 --> 00:11:14,960 have thrived there and some of them adopted there. 190 00:11:14,960 --> 00:11:18,880 So some Organism disappeared because the conditions vanished 191 00:11:19,320 --> 00:11:22,480 and that wetland was no longer there, but some of these species 192 00:11:22,480 --> 00:11:25,320 adopted. A nice example of that are the 193 00:11:25,320 --> 00:11:29,000 pink river dolphin. That's a very iconic Organism 194 00:11:29,000 --> 00:11:32,080 that we all love, and it arrived from the oceans. 195 00:11:32,080 --> 00:11:34,760 It came with the marine incursions such as fish as 196 00:11:34,760 --> 00:11:38,120 welded and they adopted there and they persist. 197 00:11:38,120 --> 00:11:41,600 So there is a legacy of these marine incursions in the fauna 198 00:11:41,840 --> 00:11:44,920 but also in the flora. There are some species that we 199 00:11:44,920 --> 00:11:48,120 think are really brought in by the marine incursions and 200 00:11:48,120 --> 00:11:50,360 settled. There's certain coastal elements 201 00:11:50,440 --> 00:11:52,920 that are found and established in the Amazon. 202 00:11:53,360 --> 00:11:57,840 Is it possible to say how far into the continent the salt 203 00:11:57,840 --> 00:12:00,600 water actually penetrated during these incursions? 204 00:12:00,800 --> 00:12:03,000 Oh yeah, thousands of kilometers. 205 00:12:03,120 --> 00:12:06,960 Some people have suggested this was just by transport of birds, 206 00:12:06,960 --> 00:12:11,040 but we think there is a lot of evidence all along the pathway 207 00:12:11,040 --> 00:12:14,200 to the Caribbean. So we have made an inventory of 208 00:12:14,600 --> 00:12:18,640 localities and we find marine Organism of different kinds. 209 00:12:18,640 --> 00:12:22,200 So we find marine protozoans that settled there and that we 210 00:12:22,200 --> 00:12:24,760 know have existed for many generations. 211 00:12:25,280 --> 00:12:29,120 We find marine alti like dinoflagellate cyst and we also 212 00:12:29,120 --> 00:12:32,520 find mangrove pollen in large quantities. 213 00:12:32,520 --> 00:12:36,880 And mangroves are typical for the coastal environment, but 214 00:12:36,880 --> 00:12:40,160 they managed to settle there as well, and they really formed an 215 00:12:40,440 --> 00:12:43,640 important vegetation unit for certain periods of time. 216 00:12:44,320 --> 00:12:48,000 And there's also some sedimentological features and 217 00:12:48,000 --> 00:12:51,600 this large founder that tell us that the marine incursions 218 00:12:51,600 --> 00:12:55,080 reached thousands of kilometers into western Brazil. 219 00:12:55,360 --> 00:12:58,000 That's fascinating. So that's really good evidence 220 00:12:58,000 --> 00:13:02,560 for the marine incursions. What about the erosional and 221 00:13:02,880 --> 00:13:05,680 soil change processes that you talked about? 222 00:13:05,680 --> 00:13:10,240 Can we see the changing sediment composition and also changing 223 00:13:10,240 --> 00:13:13,800 climate that you mentioned caused by the rise of the Andes? 224 00:13:13,800 --> 00:13:15,680 Can you see that in the geological record? 225 00:13:16,120 --> 00:13:18,560 Yeah. It was particularly important to 226 00:13:18,640 --> 00:13:23,320 use some of the available court sections for that from the 227 00:13:23,400 --> 00:13:28,720 Brazilian Geological Survey. And so we see this transition of 228 00:13:29,040 --> 00:13:33,120 stable kratomic minerals in the base of the core in the early 229 00:13:33,120 --> 00:13:36,360 myosin and then transitioning in the course of the early myosin 230 00:13:36,360 --> 00:13:39,560 to middle myosin into Ambien sediments. 231 00:13:40,000 --> 00:13:43,400 And So what we had seen an outcrop these contrasting type 232 00:13:43,400 --> 00:13:47,400 of sediments, we also could follow that in core sediments. 233 00:13:47,680 --> 00:13:51,600 And at the same time, by using Pollen's force, we could set up 234 00:13:51,600 --> 00:13:55,640 a bio stratigraphic scheme to to attach some ages to these 235 00:13:55,640 --> 00:13:58,640 sediments. And so that led us to propose 236 00:13:58,640 --> 00:14:02,400 this model of having a transition in the early to 237 00:14:02,400 --> 00:14:04,320 middle Miocene. And when you look at the 238 00:14:04,320 --> 00:14:06,840 geological models of the omelets, that fits with what's 239 00:14:06,840 --> 00:14:10,400 happening there. Subsequently, from the Atlantic, 240 00:14:10,400 --> 00:14:15,360 we also see similar change. We see a change from kratomic 241 00:14:15,360 --> 00:14:18,680 sediment to ambient sediment. When the Amazon River arrives 242 00:14:18,680 --> 00:14:22,840 there, again, the geochemical imprint is left in the sediment, 243 00:14:22,840 --> 00:14:24,960 and we see that there are 10 million years. 244 00:14:25,400 --> 00:14:29,320 With the help of the subsurface sections, together with outcrops 245 00:14:29,320 --> 00:14:32,520 of course as well, we can little by little piece together the 246 00:14:32,600 --> 00:14:35,680 story. As you mentioned, most of the 247 00:14:35,920 --> 00:14:40,680 Amazon region is actually on the Amazon Kraton, which is 248 00:14:40,680 --> 00:14:44,880 extremely old and yes, OK, so it would be somewhat starved of 249 00:14:44,880 --> 00:14:48,280 nutrients, but on the other hand it would have had plenty of time 250 00:14:48,800 --> 00:14:51,000 to develop a lot of biodiversity. 251 00:14:51,000 --> 00:14:55,720 So where we starting from a fairly bio diverse base if you 252 00:14:55,720 --> 00:14:58,440 like, when all these events we're talking about with the 253 00:14:58,440 --> 00:15:00,720 rise of the Andes took place? For sure. 254 00:15:00,720 --> 00:15:04,840 The Amazon has been actually very diverse since the 255 00:15:05,520 --> 00:15:10,560 Cretaceous Tertiary events and the famous events of the impact 256 00:15:11,120 --> 00:15:13,920 and the transition to a tropical rainforest. 257 00:15:13,920 --> 00:15:16,680 OK, that's not exactly Amazon. It's a bit further north. 258 00:15:17,080 --> 00:15:20,680 The transition to this forest that we now think of tropical 259 00:15:20,680 --> 00:15:23,160 rainforest, really initiates in the Paleogene. 260 00:15:23,800 --> 00:15:27,080 Also, it's important to realize that the Amazon previously was 261 00:15:27,080 --> 00:15:29,720 linked really with what is now the Orinoco base. 262 00:15:29,720 --> 00:15:31,760 And so it was like a mega Amazon region. 263 00:15:31,760 --> 00:15:35,880 This division only appeared in the late Miocene. 264 00:15:35,880 --> 00:15:39,880 So the area was much bigger prior to this late Miocene 265 00:15:39,880 --> 00:15:42,280 division. And so we know that that region 266 00:15:42,280 --> 00:15:46,360 was very rich and also the kratom has been already rich. 267 00:15:46,960 --> 00:15:49,000 However, this is a relative concept. 268 00:15:49,000 --> 00:15:52,400 So between Eastern and Western Amazon, the Western Amazon is 269 00:15:52,400 --> 00:15:54,840 much richer. And at global scale, it is the 270 00:15:54,840 --> 00:15:58,000 biggest rainforest in the most biodiverse region in the world. 271 00:15:58,880 --> 00:16:02,640 You mentioned palinology a moment ago, and a lot of your 272 00:16:02,640 --> 00:16:06,840 research has been in the field of palinology, which is a study 273 00:16:06,840 --> 00:16:11,880 of pollen and spores. Does the geological record in 274 00:16:11,880 --> 00:16:15,240 the Amazon basin contain a fossil record of pollinance 275 00:16:15,360 --> 00:16:19,640 pores and was that really how you determine the increasing 276 00:16:19,640 --> 00:16:23,680 biodiversity during the Miocene? Yeah, the pollinance pores are 277 00:16:23,800 --> 00:16:28,000 very good indicators of change in vegetation and also can give 278 00:16:28,000 --> 00:16:31,120 us hints to climate. The reason we can work with them 279 00:16:31,120 --> 00:16:34,440 is because they are everywhere. They are in your hair, in your 280 00:16:34,440 --> 00:16:37,960 nose and in the Amazon. They also are deposited in the 281 00:16:38,000 --> 00:16:41,280 fluvial and in the fluvulaca stream deposits. 282 00:16:41,520 --> 00:16:45,440 The main thing pollen spores don't resist is repetitive 283 00:16:45,440 --> 00:16:48,360 weathering, oxidation. So they need an anoxic 284 00:16:48,360 --> 00:16:52,320 environment for preservation. So that is what we always 285 00:16:52,320 --> 00:16:56,040 looking for is for organic material to extract pollen 286 00:16:56,040 --> 00:16:59,240 spores from there. And then you need a good lab to 287 00:16:59,240 --> 00:17:02,760 process the samples. But when you have everything 288 00:17:02,760 --> 00:17:07,119 lined up, then you can extract this huge biodiversity of the 289 00:17:07,119 --> 00:17:11,240 past from just a cubic centimeter of material. 290 00:17:11,720 --> 00:17:14,960 And we find thousands and thousands of species and we only 291 00:17:15,200 --> 00:17:18,119 little by little are understanding now this diversity 292 00:17:18,119 --> 00:17:20,280 of the past. And it gives us an interesting 293 00:17:20,280 --> 00:17:23,560 clue that, well, from one side, we know from studies on the 294 00:17:23,560 --> 00:17:26,520 packaging that it was a diverse forest, but we also can tell 295 00:17:26,520 --> 00:17:30,800 something about this huge diversity of the last 23 million 296 00:17:30,800 --> 00:17:34,160 years in the Amazon. And, and we see big changes 297 00:17:34,160 --> 00:17:38,800 depending on the environmental conditions on the chemistry of 298 00:17:38,800 --> 00:17:42,840 the system, but we see a high diversity throughout. 299 00:17:43,560 --> 00:17:47,680 We're now looking into later part in the the history with a 300 00:17:47,680 --> 00:17:51,080 new core that has been drilled and it will be very interesting 301 00:17:51,080 --> 00:17:54,040 to see if there's actually a decline in the late Miocene when 302 00:17:54,040 --> 00:17:55,520 there's global cooling happening. 303 00:17:56,160 --> 00:18:00,320 Are these spores the actual original organic material of the 304 00:18:00,320 --> 00:18:03,840 spores or are they fossilized spores where the materials being 305 00:18:03,840 --> 00:18:06,640 replaced by minerals? The pollen spores, they are made 306 00:18:06,640 --> 00:18:11,720 of very durable component which is the sporopolynine, that is a 307 00:18:11,920 --> 00:18:15,600 pollen wall that encapsulates the DNA, the plant DNA. 308 00:18:15,600 --> 00:18:19,280 But that part is gone. But the sporopolynine is a 309 00:18:19,280 --> 00:18:23,520 relict of the original plant. And retains the structure. 310 00:18:23,600 --> 00:18:26,160 Yeah, exactly. So it retains its composition 311 00:18:26,160 --> 00:18:28,360 and structure. And in fact we work with that 312 00:18:28,360 --> 00:18:32,400 structure because Poland have a very distinct morphology. 313 00:18:32,400 --> 00:18:35,520 And based on those morphological elements, we can classify them 314 00:18:35,520 --> 00:18:38,080 and also relate them to modern species. 315 00:18:38,080 --> 00:18:41,040 So we can assign a botanical affinity to them. 316 00:18:41,040 --> 00:18:43,840 And in that way we can understand more about 317 00:18:43,840 --> 00:18:47,440 composition of the forest and how the forest changed or how 318 00:18:47,440 --> 00:18:52,480 the swamp palms changed. What else did you use to measure 319 00:18:52,640 --> 00:18:56,240 the history of biodiversity, especially a fauna, in addition 320 00:18:56,240 --> 00:18:59,320 to the flora? Yeah, the sediments of the paper 321 00:18:59,320 --> 00:19:03,200 system that very rich in molluscs and in ostracods, but 322 00:19:03,200 --> 00:19:07,800 also all kind of vertebrates. So these components tell us 323 00:19:07,800 --> 00:19:12,320 about how rich this environment was and how diverse and also how 324 00:19:12,320 --> 00:19:17,200 different it was in that we had a very rich system there that 325 00:19:17,200 --> 00:19:20,360 was different from the present. It has been a very dynamic 326 00:19:20,360 --> 00:19:23,480 environment. The Amazon is seen now as the 327 00:19:23,480 --> 00:19:26,920 most rich forest and and that we should protect that. 328 00:19:26,920 --> 00:19:30,240 But we learn from the fossil record that it has also been a 329 00:19:30,240 --> 00:19:33,560 different system and that it has evolved a lot through time, 330 00:19:33,560 --> 00:19:36,920 responding to climate change, from global warming to global 331 00:19:36,920 --> 00:19:39,840 cooling and transitioning into the present. 332 00:19:40,560 --> 00:19:44,640 So obviously you were able to access the geological record to 333 00:19:44,640 --> 00:19:48,200 be able to find these spores and the fossils of the animals and 334 00:19:48,200 --> 00:19:50,560 so on. But the present day Amazon is 335 00:19:50,560 --> 00:19:56,280 extremely densely vegetated. How were you able to find any 336 00:19:56,280 --> 00:19:58,320 outcrops there to make your measurements? 337 00:19:58,960 --> 00:20:02,320 So first of all, we had a location in western Amazon in 338 00:20:02,320 --> 00:20:05,880 Colombia that was our base camp that was an old prison just like 339 00:20:05,880 --> 00:20:08,320 Papillon in the French Guiana almost. 340 00:20:08,880 --> 00:20:13,360 And from there we could access the river and we travel along 341 00:20:13,360 --> 00:20:17,200 the river to find out crops and at the same time also work 342 00:20:17,200 --> 00:20:20,680 together with local assistant indigenous people who knew the 343 00:20:20,680 --> 00:20:23,320 region well. So a lot of it was based on 344 00:20:23,320 --> 00:20:25,640 interviewing them and asking them for advice. 345 00:20:25,640 --> 00:20:27,800 And at some point, of course, they knew what I was looking 346 00:20:27,800 --> 00:20:28,840 for. So that made it. 347 00:20:28,960 --> 00:20:33,400 Easier and so we would travel to find out crops, but they are far 348 00:20:33,400 --> 00:20:38,240 apart and it's not always easy. But of course a very important 349 00:20:38,240 --> 00:20:42,240 element as well is working with court sections. 350 00:20:42,240 --> 00:20:46,080 And obtaining that material was transformational for 351 00:20:46,080 --> 00:20:50,800 understanding the Amazon because you have to tie out crops and 352 00:20:50,800 --> 00:20:54,080 records together to get the bigger picture, to understand 353 00:20:54,360 --> 00:20:58,000 really the stratigraphy and use biosatigraphy to put ages to 354 00:20:58,000 --> 00:21:01,680 that. And so the combination between 355 00:21:01,680 --> 00:21:04,360 outcrops and court sections is very crucial. 356 00:21:04,960 --> 00:21:08,760 There are some oil wells in the region, I believed. 357 00:21:09,160 --> 00:21:12,480 Did the oil companies cooperate with you and give you access to 358 00:21:12,480 --> 00:21:15,240 some of their drill cores? Yeah, it's pretty rare for 359 00:21:15,240 --> 00:21:18,080 companies to do that because it's all confidential 360 00:21:18,080 --> 00:21:21,400 information. And I've tried many times, but I 361 00:21:21,400 --> 00:21:25,280 was very fortunate and I'm also grateful to the possibilities 362 00:21:25,280 --> 00:21:29,840 that were given by the Brazilian oil company Petrobras. 363 00:21:30,080 --> 00:21:33,560 So there were several windows of opportunities that allowed us to 364 00:21:33,560 --> 00:21:37,240 work with court sections in the Western Amazon, but also at the 365 00:21:37,240 --> 00:21:41,040 mouth of the Amazon. And those opportunities have 366 00:21:41,040 --> 00:21:44,520 really allowed us to advance our knowledge on the Amazon. 367 00:21:45,240 --> 00:21:46,800 What are you working on at the moment? 368 00:21:47,360 --> 00:21:49,760 At the moment, I'm trying to better understand the 369 00:21:50,080 --> 00:21:52,520 composition of the mangrove coastal system. 370 00:21:52,520 --> 00:21:56,080 So we talked about these marine incursions and the mangroves 371 00:21:56,080 --> 00:21:59,760 that existed there. And nowadays, the mangroves of 372 00:21:59,760 --> 00:22:03,200 the neotropics of northern South America, they're quite 373 00:22:03,200 --> 00:22:07,040 impoverished compared to, for instance, the Asian mangroves. 374 00:22:07,040 --> 00:22:10,480 But when we look at the past, for instance, the Miocene, we 375 00:22:10,480 --> 00:22:13,640 already start noticing that there was more diversity in 376 00:22:13,640 --> 00:22:15,880 mangroves than there is at present. 377 00:22:15,880 --> 00:22:18,600 So we're intrigued about that and trying to better understand 378 00:22:18,600 --> 00:22:20,880 that. Also trying to understand the 379 00:22:20,960 --> 00:22:25,240 relation between geodiversity and modern distribution of 380 00:22:25,240 --> 00:22:27,800 organisms. So trying different things to 381 00:22:28,000 --> 00:22:30,200 still advance knowledge in the region. 382 00:22:31,120 --> 00:22:33,080 Karina Horne, thank you very much. 383 00:22:33,480 --> 00:22:36,040 Thank you so much. It was very nice to talk to you. 384 00:22:37,600 --> 00:22:40,160 To see pictures and illustrations that support this 385 00:22:40,160 --> 00:22:45,440 podcast, go to geologybytes.com, where you'll also find a subject 386 00:22:45,440 --> 00:22:47,360 matter index of all the episodes. 387 00:22:47,800 --> 00:22:51,160 There you can also give me feedback which I welcome, as 388 00:22:51,160 --> 00:22:54,160 well as sign up to get my emails about new episodes.