WEBVTT 00:02.803 --> 00:04.338 >>NARRATOR: Reaching up into the water 00:04.338 --> 00:09.610 like the branches of trees, they are thousands of organisms 00:09.610 --> 00:11.812 living together as one. 00:11.812 --> 00:15.449 And together they provide shelter and protection 00:15.449 --> 00:17.885 for many more. 00:17.885 --> 00:20.487 >>This is really important for a lot of different 00:20.487 --> 00:24.892 marine organisms and provides a refuge for these organisms. 00:26.627 --> 00:28.362 >>NARRATOR: Once a common sight, 00:28.362 --> 00:31.365 elkhorn and staghorn corals were the dominant 00:31.365 --> 00:35.302 shallow reef building corals in the Caribbean and Florida. 00:35.302 --> 00:37.337 >>Coral reefs are under extreme stress toda 00:37.337 --> 00:42.543 from a variety of causes, both globally and locally. 00:42.543 --> 00:44.845 >>In the past 30 years, elkhorn and the staghorn 00:44.845 --> 00:48.916 have declined dramatically, between 90% and 98%, 00:48.916 --> 00:50.784 throughout the Caribbean. 00:50.784 --> 00:52.719 They're now listed as threatened under 00:52.719 --> 00:55.989 the U.S. Endangered Species Act... 00:55.989 --> 00:59.526 >>And are much reduced from their former glory. 00:59.526 --> 01:02.763 >>NARRATOR: Primarily, disease as well as some other factors 01:02.763 --> 01:05.132 has led to the drop in numbers 01:05.132 --> 01:08.368 of elkhorn and staghorn colonies. 01:08.368 --> 01:12.105 But while these corals have declined in recent years, 01:12.105 --> 01:15.442 their hybrid appears to be increasing 01:15.442 --> 01:17.544 in parts of the region. 01:17.544 --> 01:19.546 >>What's really cool about this hybridizing system 01:19.546 --> 01:23.083 is that the hybrid is not found in the fossil record. 01:23.083 --> 01:25.152 They seem to be increasing recently, 01:25.152 --> 01:29.389 likely due to the decrease in the parental species. 01:29.389 --> 01:32.459 >>NARRATOR: Often found in really shallow water, 01:32.459 --> 01:36.330 this hybrid, commonly called fused staghorn, 01:36.330 --> 01:39.066 closely resembles its parents. 01:39.066 --> 01:42.102 >>You have some that look very much like staghorn 01:42.102 --> 01:44.605 and then others that look like elkhorn. 01:44.605 --> 01:47.374 Most of the ones that I've seen throughout all my study sites 01:47.374 --> 01:51.712 in the Caribbean have more of a staghorn look to them, 01:51.712 --> 01:55.649 but they're more tightly clumped than the branching staghorn. 01:59.052 --> 02:01.355 >>NARRATOR: Could these hybrids be better equipped 02:01.355 --> 02:04.591 at dealing with environmental stressors? 02:04.591 --> 02:07.361 Might they be filling a niche left behind 02:07.361 --> 02:10.597 by the decline of their parents? 02:36.123 --> 02:38.725 >> Major funding for this  program was provided 02:38.725 --> 02:42.129 by the Batchelor Foundation,  encouraging people 02:42.129 --> 02:48.969 to preserve and protect  America's underwater resources. 02:48.969 --> 02:53.206 And by Divers Direct,  inspiring the pursuit 02:53.206 --> 02:56.576 of tropical adventure  scuba diving. 03:09.189 --> 03:12.325 >>NARRATOR: Dr. Nicole Fogarty is an Assistant Professor 03:12.325 --> 03:14.294 at Nova Southeastern University's 03:14.294 --> 03:19.599 Oceanographic Center. 03:19.599 --> 03:22.402 She studies the hybrids at various sites 03:22.402 --> 03:24.504 across the Caribbean. 03:34.748 --> 03:36.917 >>I was really interested in this hybridization 03:36.917 --> 03:39.186 between these two threatened species. 03:39.186 --> 03:44.324 There's very little that's known about the hybridization. 03:44.324 --> 03:47.728 >>NARRATOR: Since 2005, she's been making 03:47.728 --> 03:50.497 regular research trips to a small island 03:50.497 --> 03:53.467 off the coast of Belize. 03:53.467 --> 03:56.503 >>The island is out on the Mesoamerican Barrier Reef, 03:56.503 --> 03:59.506 so you really can literally roll off the island 03:59.506 --> 04:01.108 and be on a coral reef. 04:01.108 --> 04:04.377 There's just a very nice reef, very, very close to the island. 04:08.749 --> 04:10.951 >>NARRATOR: The Mesoamerican Reef stretches along 04:10.951 --> 04:15.956 the coasts of Mexico, Belize, Guatemala and Honduras. 04:15.956 --> 04:18.525 It is considered the largest barrier reef 04:18.525 --> 04:22.295 in the Western Hemisphere, covering nearly 700 miles 04:22.295 --> 04:25.365 from the northern tip of the Yucatan Peninsula 04:25.365 --> 04:28.001 down to the Honduran Bay Islands. 04:41.381 --> 04:45.385 Carrie Bow Cay is located 15 miles offshore 04:45.385 --> 04:48.588 from the Belizean town of Dangriga. 04:48.588 --> 04:53.827 It has been a research facility of the Smithsonian Institution 04:53.827 --> 04:57.264 since 1972. 04:57.264 --> 04:59.599 >>We just celebrated our 40th year anniversary, 04:59.599 --> 05:02.936 and we've got over 930 scientific publications 05:02.936 --> 05:05.138 that have come from the island, including a few books 05:05.138 --> 05:08.475 that have all resulted from the work at Carrie Bow. 05:08.475 --> 05:10.577 It's really contributed a lot to our understanding 05:10.577 --> 05:14.281 of coral reef ecosystems in the Caribbean. 05:14.281 --> 05:17.651 >>NARRATOR: The island is an ideal place to study the hybrid 05:17.651 --> 05:23.790 because of its proximity to all three types of corals. 05:23.790 --> 05:26.426 >>There's a wonderful population just off 05:26.426 --> 05:28.328 the southern end of the island. 05:28.328 --> 05:29.663 It has both the staghorn, 05:29.663 --> 05:32.899 the elkhorn and the hybrid of those two species. 06:03.897 --> 06:05.665 >>NARRATOR: When Nicole first started coming 06:05.665 --> 06:10.036 to Carrie Bow Cay, she wanted to understand why the hybrids 06:10.036 --> 06:13.974 might be increasing in numbers. 06:13.974 --> 06:16.009 >>One possibility is that there's 06:16.009 --> 06:18.745 an actual increase in hybrid formation, 06:18.745 --> 06:21.081 so the egg and sperm of staghorn and elkhorn 06:21.081 --> 06:25.552 are mixing to form an embryo that's a hybrid 06:25.552 --> 06:28.021 that will eventually go and settle and grow 06:28.021 --> 06:30.690 into an adult hybrid coral. 06:30.690 --> 06:32.993 The other possibility is that we have an increase 06:32.993 --> 06:35.428 in asexual fragmentation. 06:35.428 --> 06:37.297 These corals are branching corals, 06:37.297 --> 06:40.901 and so they can break off and fragment, reattach 06:40.901 --> 06:43.737 to the bottom and then continue to grow. 06:43.737 --> 06:45.138 So that's a very important aspect 06:45.138 --> 06:47.107 of their life history stage. 06:47.107 --> 06:49.709 So you could imagine if there's just a few rare 06:49.709 --> 06:53.046 hybrid events that formed decades ago, these hybrids 06:53.046 --> 06:58.718 could just fragment repeatedly over the years. 06:58.718 --> 07:00.887 The other possibility is that the hybrid 07:00.887 --> 07:04.724 is actually more viable than the parental species 07:04.724 --> 07:07.260 and might show increased fitness. 07:07.260 --> 07:08.795 It's called "hybrid vigor." 07:08.795 --> 07:13.099 And so we have hybrids that have been established over the years. 07:13.099 --> 07:15.702 And when you have the disease outbreak 07:15.702 --> 07:18.171 and disturbance and other things that have led to the decline 07:18.171 --> 07:21.041 in the parental species, the hybrid's actually able 07:21.041 --> 07:23.643 to withstand all those different events. 07:23.643 --> 07:26.012 And that's why they're increasing in numbers 07:26.012 --> 07:28.748 and are higher in abundance at some of the sites. 07:43.964 --> 07:46.066 >>NARRATOR: To test these hypotheses, 07:46.066 --> 07:48.969 Nicole decided to conduct a number of experiments 07:48.969 --> 07:52.038 when the corals were spawning. 07:52.038 --> 07:54.941 >>Staghorn and elkhorn coral only spawn once a year, 07:54.941 --> 07:58.311 usually in late summer-- July, August, or September. 07:58.311 --> 08:01.481 So that means one night out of the year, they release 08:01.481 --> 08:03.450 gamete bundles, and those gamete bundles 08:03.450 --> 08:06.519 are full of both egg and sperm. 08:06.519 --> 08:09.889 Each individual polyp that makes up a coral colon 08:09.889 --> 08:12.025 will form one gamete bundle. 08:12.025 --> 08:14.761 It takes the polyp about nine months 08:14.761 --> 08:17.063 to create the egg and about six months 08:17.063 --> 08:18.565 to create the sperm. 08:18.565 --> 08:21.468 So there's a lot of energy being invested in forming 08:21.468 --> 08:23.036 these gametes. 08:23.036 --> 08:26.039 The gamete bundles are released in one synchronized pulse. 08:26.039 --> 08:28.908 They float up to the surface, break apart, mix with 08:28.908 --> 08:31.411 other gametes from other individual corals 08:31.411 --> 08:35.048 from the same species, or sometimes hybridize, 08:35.048 --> 08:38.351 and then fertilization occurs at the surface. 08:38.351 --> 08:40.153 The resulting embryos then float around 08:40.153 --> 08:43.023 for a couple of days before developing into larvae. 08:43.023 --> 08:44.724 And then the larvae will float around 08:44.724 --> 08:47.160 for a few more days before they start swimming 08:47.160 --> 08:50.530 down to the bottom, looking for a good place to settle. 08:50.530 --> 08:53.333 They'll attach to the bottom, metamorphose, and grow into 08:53.333 --> 08:58.004 an adult coral. 08:58.004 --> 09:00.106 >>NARRATOR: Staghorn and elkhorn corals 09:00.106 --> 09:03.109 are very plantlike creatures. 09:03.109 --> 09:05.812 >>And so really, when you're thinking about corals, 09:05.812 --> 09:09.082 even though they're animals, their evolutionary background 09:09.082 --> 09:13.019 and evolutionary trajectory are much more like plants. 09:13.019 --> 09:15.088 They are hermaphrodites. 09:15.088 --> 09:18.324 They are attached to the bottom just like adult plants are. 09:18.324 --> 09:22.028 They broadcast spawn their gametes like many plants do. 09:22.028 --> 09:25.231 They're long-lived like plants, and they also can 09:25.231 --> 09:27.033 asexually fragment. 09:27.033 --> 09:30.837 They asexually propagate like many plants. 09:32.038 --> 09:33.773 >>NARRATOR: Using a tentlike net, 09:33.773 --> 09:38.244 Nicole collected the gametes of both elkhorn and staghorn corals 09:38.244 --> 09:41.548 on the nights they were spawning. 09:41.548 --> 09:44.651 >>We bring those gametes back into the lab. 09:44.651 --> 09:47.854 We can separate the gametes out to sperm and stock solution 09:47.854 --> 09:49.689 and then we can play "mad scientist," where we do 09:49.689 --> 09:54.427 all kinds of different fertilization assays. 09:54.427 --> 09:57.230 Now that we've separated them out into our sperm 09:57.230 --> 10:00.100 and egg solutions, we're going to conduct a series 10:00.100 --> 10:02.435 of fertilization experiments. 10:02.435 --> 10:04.871 And so, we're looking at fertilization between 10:04.871 --> 10:08.241 the elkhorn and the staghorn, and this is crosses between 10:08.241 --> 10:11.644 the staghorn eggs and the elkhorn sperm. 10:16.616 --> 10:21.821 And now I am going to add one milliliter of eggs to the vials. 10:21.821 --> 10:25.258 After I complete this cross, then we'll do 10:25.258 --> 10:28.528 the reciprocal cross and mix staghorn sperm 10:28.528 --> 10:31.164 with the elkhorn eggs. 10:31.164 --> 10:33.633 And then we can do it with sperm competition. 10:33.633 --> 10:35.368 That's when we mix both the staghorn 10:35.368 --> 10:38.571 and the elkhorn sperm together and then introduce the sperm 10:38.571 --> 10:41.975 to the staghorn eggs or introduce the sperm mixtures 10:41.975 --> 10:43.710 to the elkhorn eggs. 10:43.710 --> 10:45.712 And that's more likely what occurs during 10:45.712 --> 10:47.780 coral spawning, because these species spawn 10:47.780 --> 10:49.415 at the same time, 10:49.415 --> 10:51.384 and so the sperm are going to be mixing, 10:51.384 --> 10:55.455 competing for who's going to actually fertilize the eggs. 10:55.455 --> 10:58.691 Once all the crosses are done, we'll let them sit 10:58.691 --> 11:04.130 for three hours and then we'll score fertilization. 11:04.130 --> 11:06.199 When we score fertilization, what we are looking for 11:06.199 --> 11:10.003 is the number of unfertilized eggs 11:10.003 --> 11:14.174 and the number of dividing embryos. 11:14.174 --> 11:16.743 >>NARRATOR: With these fertilization experiments, 11:16.743 --> 11:19.946 Nicole tried to determine if there may be 11:19.946 --> 11:25.251 gametic incapability, which means one species' sperm 11:25.251 --> 11:29.255 can't fertilize the other species' eggs. 11:29.255 --> 11:31.457 >>What we found out is that both the staghorn eggs 11:31.457 --> 11:34.360 and the elkhorn eggs are able to hybridize, 11:34.360 --> 11:37.530 but the elkhorn eggs are a little more resistant 11:37.530 --> 11:40.033 to hybridization than the staghorn eggs. 11:40.033 --> 11:42.402 The staghorn eggs can be fertilized 11:42.402 --> 11:47.507 by the elkhorn sperm just as easy as their own species sperm. 11:47.507 --> 11:51.711 In the sperm competition assays, we found the similar result. 11:51.711 --> 11:54.147 The eggs of elkhorn are a little more resistant, 11:54.147 --> 11:57.450 and then the eggs of staghorn are more easily fertilized 11:57.450 --> 11:59.519 by not only their own species sperm 11:59.519 --> 12:01.654 but the elkhorn sperm, as well. 12:01.654 --> 12:03.957 So it can happen in both directions, 12:03.957 --> 12:06.226 but hybridization occurs more frequentl 12:06.226 --> 12:07.694 with the staghorn eggs. 12:17.670 --> 12:20.673 >>NARRATOR: Next, Nicole looked into the viabilit 12:20.673 --> 12:24.277 of the hybrids. 12:24.277 --> 12:27.447 >>The hybrid might be sterile, such as the mule example, 12:27.447 --> 12:29.482 when a donkey and a horse mate. 12:29.482 --> 12:33.353 Or it might just be inviable, so it has decreased fitness, 12:33.353 --> 12:35.822 and it's not able to persist in an environment. 12:35.822 --> 12:38.258 Perhaps it's more susceptible to disease 12:38.258 --> 12:40.460 or temperature fluctuations. 12:40.460 --> 12:43.596 So these are the type of things that I wanted to look at. 12:43.596 --> 12:45.198 And what we found was that the hybrid 12:45.198 --> 12:47.634 was not inferior across any life history stage 12:47.634 --> 12:49.002 that we looked at. 12:49.002 --> 12:51.771 That includes the larval stage, during settlement, 12:51.771 --> 12:54.707 throughout metamorphosis, and also as an adult. 12:54.707 --> 12:57.110 We also found that hybrids can persist 12:57.110 --> 12:59.112 in the shallow marginal environments 12:59.112 --> 13:01.681 they're often found, but also can persist and grow 13:01.681 --> 13:04.684 in the parental species habitat without a problem. 13:14.661 --> 13:17.597 >>NARRATOR: And Nicole made another interesting discover 13:17.597 --> 13:21.968 at her study site in Belize. 13:21.968 --> 13:23.936 >>The hybrid, even though they're often in just 13:23.936 --> 13:27.540 two or three feet of water, are no more likely to bleach 13:27.540 --> 13:31.010 than the parental species that are in deeper water. 13:31.010 --> 13:34.814 And so this could be that the hybrid is more tolerant 13:34.814 --> 13:38.651 of fluctuations in temperature-- not only increase in temperature 13:38.651 --> 13:41.154 during the summertime, but those shallow areas 13:41.154 --> 13:44.390 also cool off really quickly during the wintertime. 13:44.390 --> 13:47.627 And there's also a lot of UV irradiance blasting those corals 13:47.627 --> 13:49.929 in that really shallow, clear water. 13:49.929 --> 13:52.231 So that's something that I'm going to be exploring further. 13:59.205 --> 14:01.607 >>NARRATOR: Coral bleaching occurs when the animals 14:01.607 --> 14:03.810 are very stressed. 14:03.810 --> 14:07.580 There are a variety of stressors that can cause bleaching, 14:07.580 --> 14:11.517 including exposure to extreme temperatures. 14:11.517 --> 14:13.920 Extreme temperatures are likely going to increase 14:13.920 --> 14:18.758 in frequency in the future because of climate change. 14:18.758 --> 14:20.893 >>Coral bleaching is when the corals lose 14:20.893 --> 14:23.763 their symbiotic dinoflagellate that's in the tissues 14:23.763 --> 14:25.231 of the coral. 14:25.231 --> 14:28.234 So corals have a symbiotic relationship 14:28.234 --> 14:31.604 with a dinoflagellate we call zooxanthellae, 14:31.604 --> 14:33.940 and the zooxanthellae is in the coral tissue. 14:33.940 --> 14:38.010 It gives the coral the golden or brown colors that you see. 14:38.010 --> 14:40.813 And what occurs is when the coral 14:40.813 --> 14:43.983 gets stressed out, that symbiotic relationship 14:43.983 --> 14:45.618 is going to break down. 14:45.618 --> 14:48.054 And so they lose that zooxanthellae, 14:48.054 --> 14:51.457 and then what you see is the white coral skeleton 14:51.457 --> 14:53.659 through the translucent tissues. 14:53.659 --> 14:56.095 Now the dinoflagellate, the zooxanthellae, 14:56.095 --> 14:58.765 is important for the corals because it gives the corals 14:58.765 --> 15:00.700 a lot of its nutrition. 15:00.700 --> 15:03.369 Corals can capture small zooplankton 15:03.369 --> 15:06.239 in their tentacles, but most of the nutrition 15:06.239 --> 15:09.375 that the coral gets is through the zooxanthellae. 15:09.375 --> 15:11.811 So when the symbiotic relationship breaks down, 15:11.811 --> 15:14.847 the coral is going to have decreased growth rates, 15:14.847 --> 15:18.418 it's going to have reduced reproductive capabilities, 15:18.418 --> 15:21.687 and so it's going to really negatively affect the coral. 15:29.695 --> 15:32.598 >>NARRATOR: one thing that is still unknown at this point 15:32.598 --> 15:39.205 is whether or not the hybrids can mate with each other. 15:39.205 --> 15:41.407 >>We know that hybrids aren't sterile because 15:41.407 --> 15:44.076 from the molecular signature, we know that the staghorn 15:44.076 --> 15:46.379 and the hybrid can mate. 15:46.379 --> 15:49.182 >>NARRATOR: However, to date, no second generation of hybrids 15:49.182 --> 15:51.050 has been discovered. 15:51.050 --> 15:52.785 >>There's a couple of different hypotheses 15:52.785 --> 15:55.087 of why we might not see a second generation, 15:55.087 --> 15:58.224 one of which is that the sampling effort was pretty low. 15:58.224 --> 16:00.393 It was only at three geographic sites 16:00.393 --> 16:02.261 and pretty low sample size. 16:02.261 --> 16:04.897 So perhaps second generation hybrids are out there, 16:04.897 --> 16:06.899 but it'll take further sampling, and that's something 16:06.899 --> 16:09.168 I am looking at as part of my research 16:09.168 --> 16:12.138 at Nova Southeastern University. 16:12.138 --> 16:14.774 The other possibility is that if hybridization 16:14.774 --> 16:20.213 is increasing, as I believe it is, then we might have 16:20.213 --> 16:23.182 more generations in the decades to come. 16:23.182 --> 16:26.185 It's just such a new event that they're increasing 16:26.185 --> 16:29.388 in numbers that they haven't had an opportunity to create 16:29.388 --> 16:32.158 a second generation. 16:32.158 --> 16:35.828 What's really interesting about this system is that 16:35.828 --> 16:38.064 the parental species are found in the fossil record 16:38.064 --> 16:40.333 for millions of years, but the hybrid 16:40.333 --> 16:41.868 has no fossil record. 16:41.868 --> 16:45.671 So it's a relatively recent event, and there is evidence 16:45.671 --> 16:47.673 that it is increasing in some sites. 16:47.673 --> 16:50.877 There are sites in Belize, in Curacao, in Florida 16:50.877 --> 16:53.279 where we know the hybrid was not at that site 16:53.279 --> 16:56.249 just five years ago, and now we see hybrids there. 16:59.552 --> 17:01.053 We also know from genetic studies 17:01.053 --> 17:03.990 that the hybrid populations are composed of 17:03.990 --> 17:07.360 multiple genotypes, meaning that there are separate 17:07.360 --> 17:09.395 hybridization events that have occurred 17:09.395 --> 17:12.131 and not just one rare hybridization event 17:12.131 --> 17:15.067 that has asexually fragmented. 17:15.067 --> 17:17.770 What I think is currently going on in this system 17:17.770 --> 17:20.172 is that, with the decline of the parental species 17:20.172 --> 17:22.975 over the past 30 years, we actually have an increase 17:22.975 --> 17:24.343 in hybridization. 17:24.343 --> 17:26.913 And how that would work is that if you imagine back 17:26.913 --> 17:30.349 before the 1980s, you had really extensive 17:30.349 --> 17:33.052 thickets of both staghorn and elkhorn. 17:33.052 --> 17:35.021 They were the primary reef builder in the shallow 17:35.021 --> 17:36.956 reef environments. 17:36.956 --> 17:40.660 And so when staghorn or elkhorn spawn, the eggs 17:40.660 --> 17:42.228 are immediately going to be swamped 17:42.228 --> 17:44.597 by their own species' sperm. 17:44.597 --> 17:47.533 And occasionally you might have had hybridization 17:47.533 --> 17:49.635 if a couple of the eggs went unfertilized, 17:49.635 --> 17:51.771 but it was a pretty rare event. 17:51.771 --> 17:54.774 Well, now you have these populations of elkhorn 17:54.774 --> 17:57.843 and staghorn that are really sparse, and so if you can 17:57.843 --> 18:00.279 imagine when they spawn, the eggs are going to go 18:00.279 --> 18:01.847 unfertilized. 18:01.847 --> 18:03.549 And at least with the staghorn eggs, 18:03.549 --> 18:04.951 whatever sperm they run into, 18:04.951 --> 18:08.187 whether it's their own species' sperm or an elkhorn sperm, 18:08.187 --> 18:09.722 that's going to fertilize it. 18:09.722 --> 18:12.592 So, we have this increase in hybrid formation 18:12.592 --> 18:16.929 because the parental species have decreased in numbers. 18:38.451 --> 18:40.753 >>NARRATOR: Long-term monitoring is necessar 18:40.753 --> 18:46.792 to truly understand the changes occurring on the reef. 18:46.792 --> 18:49.295 >>Only through long-term observations over time 18:49.295 --> 18:51.831 can you evaluate and find new discoveries, and I think 18:51.831 --> 18:54.967 it's paid off in a big way. 18:54.967 --> 18:57.703 >>NARRATOR: In 2011, Nicole created 18:57.703 --> 19:01.941 a demographic study off the south end of the island. 19:01.941 --> 19:04.543 >>As far as we know, we're the only demographic stud 19:04.543 --> 19:07.146 Caribbean-wide that looks at both the elkhorn, staghorn 19:07.146 --> 19:09.115 and the hybrid. 19:09.115 --> 19:11.851 We established seven circular plots, 19:11.851 --> 19:13.686 and these are permanent plots. 19:13.686 --> 19:16.589 So every three to four months, we go back and look at 19:16.589 --> 19:18.924 every individual elkhorn, staghorn or hybrid 19:18.924 --> 19:20.092 in these plots. 19:31.837 --> 19:36.208 >>NARRATOR: Each of the seven plots has a buoy at its center. 19:36.208 --> 19:38.611 >>And then we took a transect line and extended it 19:38.611 --> 19:41.213 seven meters from the center. 19:41.213 --> 19:43.816 We then tagged every single coral colon 19:43.816 --> 19:48.387 within that seven-meter radius in that circular plot. 19:48.387 --> 19:51.057 We also mapped it, and how we do that is 19:51.057 --> 19:53.359 we take the transect line from that center buo 19:53.359 --> 19:56.662 and extend it out to the focal colony. 19:56.662 --> 19:59.565 And then someone at the center buoy has a compass, 19:59.565 --> 20:02.368 looking at their compass, and then will give us 20:02.368 --> 20:05.938 the different numbers for that compass bearing. 20:05.938 --> 20:08.307 Whoever is at the focal colony will then write down 20:08.307 --> 20:11.277 the distance from the center buoy, and then also 20:11.277 --> 20:13.579 that compass bearing that the person at the center 20:13.579 --> 20:15.481 then gave them. 20:15.481 --> 20:18.684 That way, we can mark each individual coral colon 20:18.684 --> 20:19.852 and where it is. 20:23.856 --> 20:25.624 >>NARRATOR: Next, tissue samples were taken 20:25.624 --> 20:29.061 for genetic analysis. 20:29.061 --> 20:31.497 >>We take small tissue samples-- about a centimeter, 20:31.497 --> 20:34.333 just like the very end of your pinky. 20:34.333 --> 20:37.636 It's only about one month of growth for these corals, 20:37.636 --> 20:40.239 so it doesn't hurt the corals at all. 20:46.846 --> 20:50.249 We take that tissue sample and preserve it. 20:50.249 --> 20:52.218 Then we take it back to the laborator 20:52.218 --> 20:56.222 and we use micro-satellite markers to be able to genotype. 20:56.222 --> 20:59.892 And then that gives us an idea of how many separate genotypes 20:59.892 --> 21:02.895 are in our population and how man 21:02.895 --> 21:07.867 of the different colonies are actually from asexual fragments. 21:07.867 --> 21:11.270 So far, we have nearly 600 corals tagged and followed 21:11.270 --> 21:13.706 over that period of time. 21:13.706 --> 21:16.909 The elkhorn coral out there is really genotypically diverse. 21:16.909 --> 21:19.245 We have over 30 genotypes out there. 21:19.245 --> 21:22.615 The staghorn is less genotypically diverse 21:22.615 --> 21:25.985 and there's only a couple unique genotypes, and the hybrid 21:25.985 --> 21:28.621 has about four or five unique genotypes. 21:37.163 --> 21:39.398 >>NARRATOR: Nicole based her demographic stud 21:39.398 --> 21:42.868 on a protocol designed and used by other scientists 21:42.868 --> 21:44.970 in the Caribbean. 21:44.970 --> 21:48.507 >>We can compare our results in the Western Caribbean 21:48.507 --> 21:50.810 with their results in Florida and elsewhere 21:50.810 --> 21:52.378 in the Eastern Caribbean. 21:52.378 --> 21:55.147 Every three to four months, we come back and we photograph 21:55.147 --> 21:57.082 each individual colony. 21:57.082 --> 22:00.486 We also assess each individual colony and so see if there's 22:00.486 --> 22:04.723 any damselfish bites, see if there's any predation, 22:04.723 --> 22:08.527 coral bleaching, disease, et cetera. 22:08.527 --> 22:12.031 >>NARRATOR: Nicole also takes length, width and height 22:12.031 --> 22:16.402 measurements of each individual colony and then estimates 22:16.402 --> 22:20.873 the percentage of live coral for each colony. 22:20.873 --> 22:23.742 >>We're also interested in how quickly these corals grow. 22:23.742 --> 22:27.213 So what we do is we take a beaded cable tie and put it 22:27.213 --> 22:30.616 about two centimeters away from the tip of the coral. 22:30.616 --> 22:35.221 The coral grows from the end, and so it will continue to grow 22:35.221 --> 22:38.824 and extend so we can measure from that beaded cable tie 22:38.824 --> 22:42.294 to the very end of the coral and see how much it grows 22:42.294 --> 22:46.065 every time period that we come out here and sample. 22:46.065 --> 22:48.968 We're going to be doing a lot of spatial analyses 22:48.968 --> 22:51.871 and being able to look how disease spreads 22:51.871 --> 22:55.741 across this population and coral bleaching, predation, 22:55.741 --> 22:58.811 and see how that changes year after year and how it 22:58.811 --> 23:01.380 affects different colonies and may spread 23:01.380 --> 23:03.115 to neighboring colonies. 23:09.588 --> 23:11.790 >>NARRATOR: In the few short years that this project 23:11.790 --> 23:14.927 has been ongoing, Nicole has already made 23:14.927 --> 23:18.297 several interesting discoveries. 23:18.297 --> 23:21.734 >>We established this project just a few months before 23:21.734 --> 23:24.270 a major disease outbreak. 23:24.270 --> 23:26.772 The other aspect is that we've already lost 23:26.772 --> 23:30.109 individual genotypes from that disease event, 23:30.109 --> 23:33.178 and lastly we're seeing some new recruits-- 23:33.178 --> 23:35.414 at least colonies that we think are new recruits. 23:35.414 --> 23:37.983 Once they get a little bit larger, we'll be able to take 23:37.983 --> 23:39.785 a tissue sample and genotype them 23:39.785 --> 23:42.254 and verify that it's a unique genotype 23:42.254 --> 23:46.959 compared to the rest of the individual colonies out there. 23:46.959 --> 23:48.694 >>So, it's really a valuable data set. 23:48.694 --> 23:51.297 There's nothing else quite like it in the Western Caribbean. 23:51.297 --> 23:53.999 There is some similar monitoring going on in the Florida Keys, 23:53.999 --> 23:58.537 and also in the Virgin Islands, but this will add a new data set 23:58.537 --> 24:01.307 for a region, the Mesoamerican Barrier Reef Region, 24:01.307 --> 24:05.611 which is really much less explored. 24:05.611 --> 24:08.414 >>What we ultimately would like to do is put this data 24:08.414 --> 24:10.149 into population models. 24:10.149 --> 24:12.751 And so, then, we can determine whether this 24:12.751 --> 24:17.489 particular population is stable, increasing or decreasing. 24:20.326 --> 24:23.696 >>NARRATOR: There are still many questions left unanswered 24:23.696 --> 24:26.498 that Nicole hopes to study. 24:30.769 --> 24:33.005 >>Because the elkhorn and the staghorn corals 24:33.005 --> 24:36.909 are the only current threatened species in the Caribbean, 24:36.909 --> 24:39.678 it's really important that we have a better handle 24:39.678 --> 24:41.180 of what's going on with them 24:41.180 --> 24:43.248 both from an ecological standpoint 24:43.248 --> 24:46.118 and also an evolutionary standpoint. 24:46.118 --> 24:48.988 And so this information not only will provide 24:48.988 --> 24:52.858 some data needed to understand the evolutionary trajector 24:52.858 --> 24:55.394 of these species, but also what's going on 24:55.394 --> 24:58.063 from the ecological perspective. 24:58.063 --> 25:01.500 If the hybrid is more tolerant to increased temperature 25:01.500 --> 25:04.870 or UV irradiance, then it's going to be able 25:04.870 --> 25:08.340 to withstand some of these harsh environmental changes 25:08.340 --> 25:12.678 that we may see associated with global climate change. 25:12.678 --> 25:16.015 If we lose one or both of the parental species, 25:16.015 --> 25:18.584 it will be interesting to know if the hybrid can reproduce 25:18.584 --> 25:23.155 among itself and can provide a genetic reservoir 25:23.155 --> 25:25.958 for some of these genes that we have lost 25:25.958 --> 25:30.763 through the extinction of the parental species. 25:30.763 --> 25:34.967 >>It's an avenue that's worthy of research and may provide 25:34.967 --> 25:37.369 some great information on how coral reefs 25:37.369 --> 25:40.873 can be restored and thrive in the future. 26:17.976 --> 26:20.646 >> Major funding  for this program was provided 26:20.646 --> 26:24.016 by the Batchelor Foundation,  encouraging people 26:24.016 --> 26:30.756 to preserve and protect  America's underwater resources. 26:30.756 --> 26:35.027 And by Divers Direct,  inspiring the pursuit 26:35.027 --> 26:39.027 of tropical adventure  scuba diving.