1 00:00:20,249 --> 00:00:20,649 [Funky 2 00:00:21,949 --> 00:00:36,132 Synth Music] 3 00:00:37,865 --> 00:00:41,765 The shorelines of the United States measure more than 88,000 miles. 4 00:00:42,432 --> 00:00:44,765 Florida has a great proportion of that, 5 00:00:44,765 --> 00:00:46,899 about 1300 miles. 6 00:00:47,599 --> 00:00:51,365 The coast in northeast Florida is classed as a high energy coastline. 7 00:00:52,098 --> 00:00:55,548 Our coast is a place of untold natural resources. 8 00:00:56,315 --> 00:00:59,682 One of these resources is its role in providing us with a place 9 00:00:59,682 --> 00:01:03,198 to which we can escape and play to seek peace and quiet. 10 00:01:04,065 --> 00:01:07,565 The coast consists of two elements the water and the land. 11 00:01:08,081 --> 00:01:11,631 The area where these two elements meet has special characteristics 12 00:01:12,048 --> 00:01:15,431 due to the periodic inundation of the saline waters of the sea 13 00:01:15,831 --> 00:01:20,831 and the forces exerted on it by both winds and waves. 14 00:01:21,314 --> 00:01:23,264 Little Talbott Island is located 15 00:01:23,264 --> 00:01:26,414 in south eastern United States along the coast of Florida. 16 00:01:27,014 --> 00:01:30,048 It is a barrier island which faces the sea on one side 17 00:01:30,348 --> 00:01:33,381 and on the other a maze of tidal creeks and wetlands 18 00:01:33,731 --> 00:01:36,497 between the Nassau River to the north and the St 19 00:01:36,497 --> 00:01:39,731 John's River to the south. 20 00:01:41,864 --> 00:01:44,981 Little Talbot became a state park in 1951. 21 00:01:45,647 --> 00:01:50,497 It consists of a central dune area covered by varied vegetation 22 00:01:50,864 --> 00:01:53,830 and a sandy beach. 23 00:01:54,097 --> 00:01:58,147 It is just one of the many barrier islands found along the southeastern 24 00:01:58,147 --> 00:02:02,230 and Gulf Coast of the United States. 25 00:02:04,664 --> 00:02:05,297 If you know, 26 00:02:05,297 --> 00:02:09,430 we come across a boardwalk to get from back at the recreational area 27 00:02:09,430 --> 00:02:12,880 out here to the beach and they sure didn't put this here for our convenience. 28 00:02:14,413 --> 00:02:16,647 This is to carry us across this dune area. 29 00:02:16,997 --> 00:02:19,880 That you can see stretching from the foredune right here 30 00:02:20,197 --> 00:02:23,646 all the way back until you run into a maritime force back here. 31 00:02:24,230 --> 00:02:26,713 And this dune area is a very, 32 00:02:26,713 --> 00:02:30,913 very precarious environment for anything growing. 33 00:02:30,996 --> 00:02:33,613 And as you look around, you don't see very many plants 34 00:02:34,246 --> 00:02:37,380 of any great height growing in this area. 35 00:02:37,396 --> 00:02:42,613 Sea Oats, You'll find on nice sunny days, You'll find some morning glory 36 00:02:42,979 --> 00:02:46,546 and some other kinds of grass, some cored grass and sea 37 00:02:46,546 --> 00:02:49,579 blight, some other types- there's a morning glory over there. 38 00:02:49,579 --> 00:02:50,829 See that little white? 39 00:02:50,829 --> 00:02:54,229 That's what's left of a blossom from yesterday. 40 00:02:54,879 --> 00:02:57,429 Okay, we want to look up here now 41 00:02:57,429 --> 00:03:01,029 at the beach vegetation and some of the 42 00:03:02,346 --> 00:03:03,229 reasons that we're 43 00:03:03,229 --> 00:03:06,229 very careful about not disturbing vegetation 44 00:03:06,229 --> 00:03:07,879 that grows on this foredune, 45 00:03:07,879 --> 00:03:10,746 in spite of all the developers that we find building 46 00:03:10,746 --> 00:03:13,779 right on these foredunes, you know, another island just when they can. 47 00:03:14,112 --> 00:03:18,679 But we want to look at the vegetation as it moves inland from the foredune 48 00:03:18,679 --> 00:03:20,645 and some of the things that it does for us. 49 00:03:20,645 --> 00:03:21,945 So let's go look at this. 50 00:03:21,945 --> 00:03:25,395 Be careful that you the do not disturb it any more than necessary. 51 00:03:26,445 --> 00:03:27,612 But look at that dune there. 52 00:03:27,612 --> 00:03:30,645 All of that new sand is fast encroaching, 53 00:03:30,645 --> 00:03:33,845 see back on to the vegetation in the back. 54 00:03:34,245 --> 00:03:38,262 And these tall plants are the sea oats, and this stuff in the foreground 55 00:03:38,262 --> 00:03:42,995 here are the Morning Glory and some other things chord grass. 56 00:03:42,995 --> 00:03:46,728 This six mile stretch of land between Nassau Sound 57 00:03:46,728 --> 00:03:50,295 and the mouth of the Saint John's River is rather unique. 58 00:03:50,295 --> 00:03:53,028 It forms one of the few barrier islands in Florida, 59 00:03:53,295 --> 00:03:55,461 which is currently undeveloped. 60 00:03:55,461 --> 00:03:58,578 Since it is a state park, it is likely to remain so. 61 00:03:59,328 --> 00:04:02,744 The island features are temporary since it faces daily 62 00:04:02,744 --> 00:04:06,261 the onslaught of wind and waves from the Atlantic Ocean. 63 00:04:07,278 --> 00:04:09,911 In doing so, it protects the Florida mainland 64 00:04:10,244 --> 00:04:13,928 from the destructive processes associated with ocean waves 65 00:04:13,928 --> 00:04:19,277 and strong wind. 66 00:04:19,277 --> 00:04:22,394 The beaches on this island are usually hot and firm. 67 00:04:24,227 --> 00:04:28,094 The sand is primarily quartz, with a relatively high percentage of heavy 68 00:04:28,094 --> 00:04:30,794 mineral. 69 00:04:30,794 --> 00:04:36,710 These dark colored minerals give the sands and the beach a black look. 70 00:04:36,710 --> 00:04:39,560 The black ones are heavy sand, heavy minerals. 71 00:04:40,010 --> 00:04:44,927 They are ilmenite, rutile, titanium, zircon, 72 00:04:45,277 --> 00:04:50,477 heavy things heavier than the white quartz sand, which is nothing but silica. 73 00:04:51,010 --> 00:04:53,860 And when you have waves like this breaking on the beach, 74 00:04:55,327 --> 00:04:57,493 they come up on the beach and they call them squash 75 00:04:57,493 --> 00:04:59,627 and then they wash back out to sea. 76 00:05:00,077 --> 00:05:02,660 And as the waves break and come up on here, 77 00:05:03,043 --> 00:05:06,310 they tend to carry the less dense white quartz 78 00:05:06,826 --> 00:05:10,160 out with them so that it steals the white sand 79 00:05:10,160 --> 00:05:14,060 takes it back out to sea with it, leaving these black minerals here 80 00:05:14,226 --> 00:05:16,843 because they're heavier and the water wants its energy. 81 00:05:16,843 --> 00:05:21,576 It doesn't have nearly the amount going out that it had coming in. 82 00:05:23,109 --> 00:05:23,626 Waves 83 00:05:23,626 --> 00:05:26,359 are responsible for another phenomenon on the beach. 84 00:05:26,743 --> 00:05:30,226 The movement of all the sand particles in a southerly direction 85 00:05:30,943 --> 00:05:33,426 waves striking the beach at an angle cause 86 00:05:33,426 --> 00:05:36,042 a very short range current along the shoreline. 87 00:05:37,459 --> 00:05:40,242 Waves striking from a predominantly north east 88 00:05:40,242 --> 00:05:42,876 direction, moved beach sand toward the south 89 00:05:43,276 --> 00:05:47,409 in the opposite direction to the north would flow of the offshore Gulf Stream. 90 00:05:47,926 --> 00:05:59,259 This phenomenon is called littoral drift. 91 00:05:59,259 --> 00:06:03,009 This is a point on the island where we're going to look at the littoral 92 00:06:03,009 --> 00:06:05,892 drift or longshore current, whatever you want to call it. 93 00:06:07,475 --> 00:06:10,158 Mr. Mullen have erected these stakes along here 94 00:06:10,658 --> 00:06:14,742 and we'll have one of the students carry a boay or a float out here, 95 00:06:14,742 --> 00:06:18,975 and then we'll watch it move hopefully south with the long shore drift. 96 00:06:19,925 --> 00:06:20,892 The compass is going 97 00:06:20,892 --> 00:06:24,158 to let us determine when the float goes by, 98 00:06:24,675 --> 00:06:29,358 by having the fur lined with the needle at north. 99 00:06:29,358 --> 00:06:32,025 I can see right in the notch 100 00:06:32,808 --> 00:06:36,408 the indicator on the mirror lined up with the axis 101 00:06:36,441 --> 00:06:39,674 will tell a 90 degree strength from a position. 102 00:06:40,274 --> 00:06:42,374 So when the float goes by, we start the timer. 103 00:06:42,758 --> 00:06:46,658 When the float goes by the last stake we stop the timer, 104 00:06:46,908 --> 00:06:50,441 with how far apart The stakes are we know how long it takes 105 00:06:50,541 --> 00:06:53,141 to go from A to Z. 106 00:06:53,858 --> 00:06:56,207 Chris, if you take the float out, 107 00:06:56,207 --> 00:06:59,474 just be on one of the waves breaking and watching for the signal to drop it. 108 00:06:59,474 --> 00:07:02,291 Let's go out just a little bit to the left of the stake here. 109 00:07:02,841 --> 00:07:04,841 Just be on one of them breaking. Okay. 110 00:07:05,291 --> 00:07:05,707 All right. 111 00:07:05,707 --> 00:07:08,591 Good enough. Ready on the compass. 112 00:07:09,607 --> 00:07:11,507 You got the clock ready? 113 00:07:11,507 --> 00:07:13,040 Ready on the other compass. 114 00:07:13,040 --> 00:07:17,507 Okay. 115 00:07:17,507 --> 00:07:19,240 All right, we're moving. 116 00:07:19,240 --> 00:07:21,374 Coming up, watch your toes, gonna get wet. 117 00:07:23,440 --> 00:07:25,724 ready on the first compass? 118 00:07:26,690 --> 00:07:28,657 Go the clock. 119 00:07:28,723 --> 00:07:32,707 Stay ready on the last compass. 120 00:07:32,707 --> 00:07:34,690 Now we know how far apart the stakes are. 121 00:07:34,690 --> 00:07:36,673 We know how fast is moving. 122 00:07:36,673 --> 00:07:39,340 Got to give us an indication of how fast the currents 123 00:07:39,340 --> 00:07:46,390 going. 124 00:07:46,390 --> 00:07:49,206 Okay. Getting close. 125 00:07:49,206 --> 00:07:49,906 Real close. 126 00:07:49,906 --> 00:07:52,073 Who's got the clock? 127 00:07:52,073 --> 00:07:55,140 Give us the signal when it goes by. 128 00:07:55,140 --> 00:07:57,606 Stop. 129 00:07:57,606 --> 00:08:02,139 Okay. 130 00:08:02,139 --> 00:08:06,006 Littoral drift is partly responsible for the erosion here at the north 131 00:08:06,006 --> 00:08:07,806 end of the island. 132 00:08:07,956 --> 00:08:09,973 Sand washed away during storms, 133 00:08:09,973 --> 00:08:12,823 migrates southward, pushed by littoral drift. 134 00:08:14,106 --> 00:08:16,272 When it reaches the southern end of the island, 135 00:08:16,539 --> 00:08:18,672 it is deposited in sand bars 136 00:08:20,472 --> 00:08:23,739 because of this migrating sand, the whole island appears 137 00:08:23,739 --> 00:08:27,822 to be moving southward toward the mouth of the Saint John's River, 138 00:08:28,272 --> 00:08:31,155 and it is very slowly closing up the Fort George 139 00:08:31,155 --> 00:08:35,105 Inlet. 140 00:08:35,105 --> 00:08:39,005 Okay, let's cut through here and we'll go up to this beach up here. 141 00:08:39,155 --> 00:08:43,389 The dune up here where it’s pretty heavily eroded. 142 00:08:43,389 --> 00:08:46,239 I want you to look at some things that we find on the beach up here 143 00:08:48,338 --> 00:08:49,572 on this beach right here. 144 00:08:49,572 --> 00:08:52,055 We have some coquina shell, this yellow shell. 145 00:08:52,688 --> 00:08:55,238 And this is a rock, remember, the 146 00:08:55,938 --> 00:08:58,155 fort down at Saint Augustine is made out of coquina. 147 00:08:58,155 --> 00:08:59,188 And this is the same material. 148 00:08:59,188 --> 00:09:03,405 If you look around on the beach, you'll find bits and pieces of coquina rock. 149 00:09:03,588 --> 00:09:05,705 Okay, let's go over here to this part of the beach 150 00:09:05,921 --> 00:09:07,488 right here at the base of this dune. 151 00:09:07,488 --> 00:09:11,105 And we'll try coring right in here. 152 00:09:11,105 --> 00:09:21,971 Chris, if you want to volunteer again. 153 00:09:21,971 --> 00:09:25,238 You know, we're standing here on nice pure sand. 154 00:09:25,604 --> 00:09:28,304 And so to record down through that, look what he's got in here. 155 00:09:28,304 --> 00:09:31,871 You see the coquina- the loose cocaine. 156 00:09:31,871 --> 00:09:35,471 And evidently it's not rock yet, or he would not be able to drive through it. 157 00:09:36,071 --> 00:09:37,571 Let's go out here on the beach further. 158 00:09:37,571 --> 00:09:42,221 Well, you see the muck, the bottom of an old marsh 159 00:09:42,221 --> 00:09:47,237 that was buried by the sand dune that was that was near where we're standing. 160 00:09:47,821 --> 00:09:49,121 Let's walk out there and 161 00:09:50,687 --> 00:09:51,620 do some coring out there 162 00:09:51,620 --> 00:10:05,987 on the beach. 163 00:10:05,987 --> 00:10:08,737 It marble's out there. 164 00:10:08,770 --> 00:10:10,820 You can see very sticky 165 00:10:11,270 --> 00:10:13,387 and the sediment is much, much thinner, 166 00:10:13,837 --> 00:10:17,320 finer grain than the sediment that makes up this sand. 167 00:10:17,320 --> 00:10:19,870 That's pretty coarse up there compared to this. 168 00:10:20,387 --> 00:10:23,270 And this is tend to be sticky because it's clay 169 00:10:23,886 --> 00:10:28,936 rather than pure sand. 170 00:10:28,936 --> 00:10:30,786 Sea level has risen and fallen 171 00:10:30,786 --> 00:10:34,270 several times during the past one and one half million years. 172 00:10:34,670 --> 00:10:40,936 As the continental glaciers expanded and contracted. 173 00:10:40,936 --> 00:10:44,886 Today's shoreline is shown here as the boundary between the land in brown 174 00:10:45,103 --> 00:10:46,536 and the sea in blue. 175 00:10:46,536 --> 00:10:50,586 About 200,000 years ago, the Earth was warmer than it is today. 176 00:10:51,169 --> 00:10:54,769 There was little or no ice in the north polar area, and sea 177 00:10:54,769 --> 00:10:58,569 level was much higher except for a few high points. 178 00:10:58,569 --> 00:11:02,269 Florida was underwater as the glacial ages began. 179 00:11:02,269 --> 00:11:05,652 Seawater was transformed to ice and sea level dropped. 180 00:11:06,369 --> 00:11:10,835 The land emerged and the Florida peninsula was much larger than it is today. 181 00:11:11,869 --> 00:11:13,452 About 12,000 years 182 00:11:13,452 --> 00:11:17,285 ago, the continental glaciers retreated for the last time. 183 00:11:17,285 --> 00:11:20,869 This marked the end of the so-called Wisconsin glacial period. 184 00:11:21,785 --> 00:11:26,018 Sea level is still rising a little less than one centimeter a year 185 00:11:26,652 --> 00:11:31,302 barrier Islands are slowly submerging and appear to be migrating landward 186 00:11:31,685 --> 00:11:37,385 away from the relentless sea. 187 00:11:37,385 --> 00:11:42,035 Here's some evidence here on Little Talbot that sea level is rising. 188 00:11:42,035 --> 00:11:43,751 And I don't mean like today 189 00:11:43,751 --> 00:11:46,868 because of the storm, but in general, sea level is rising. 190 00:11:47,718 --> 00:11:50,118 And if we look up, this is a good place right here 191 00:11:52,851 --> 00:11:53,768 to look at 192 00:11:53,768 --> 00:11:56,418 some shells that provide us with a little bit of evidence. 193 00:11:56,901 --> 00:11:59,651 That sea level has been rising since the last 194 00:11:59,751 --> 00:12:03,718 ice melted approximately 10,000 years ago. 195 00:12:03,734 --> 00:12:04,718 and the ice. 196 00:12:04,718 --> 00:12:07,451 The glaciers were all over the United States and had 197 00:12:07,701 --> 00:12:11,718 sea water tied up in ice and sea level drop. 198 00:12:11,718 --> 00:12:13,034 And so way out at sea. 199 00:12:13,034 --> 00:12:17,901 Now, there were some ancient barrier islands that preceded Little Talbott. 200 00:12:18,817 --> 00:12:22,334 And so those islands are now fast being eroded 201 00:12:22,784 --> 00:12:25,601 and the material just dumped on our beaches now. 202 00:12:25,601 --> 00:12:26,917 So all these black shells are 203 00:12:26,917 --> 00:12:31,100 really fossil shells from within the last 10,000 years or so. 204 00:12:32,767 --> 00:12:33,517 The shoreline 205 00:12:33,517 --> 00:12:37,517 today at Little Talbott Island is a gently sloping sand beach 206 00:12:37,517 --> 00:12:41,684 terminated by a dune ridge, 207 00:12:41,684 --> 00:12:44,767 the dune ridge is a deposit of windblown sand 208 00:12:50,467 --> 00:12:52,817 starting from the base of the Fore dune. 209 00:12:52,817 --> 00:12:55,117 We move across the back shore of the beach. 210 00:12:55,567 --> 00:12:57,883 This is also known as the beach berm. 211 00:12:58,400 --> 00:13:01,966 The berm or back shore rises gently to a crest. 212 00:13:03,583 --> 00:13:07,100 Sand that replenishes the dunes has its source in the berm. 213 00:13:08,533 --> 00:13:11,750 From the berm crest, the beach slopes gently seaward. 214 00:13:12,216 --> 00:13:14,683 This area of the beach is called the foreshore. 215 00:13:15,516 --> 00:13:18,499 The area from the low tide line seaward is called 216 00:13:18,499 --> 00:13:23,383 the offshore area. 217 00:13:23,383 --> 00:13:25,066 Let's look at what we've got here now. 218 00:13:25,066 --> 00:13:31,066 We're trying to look at the beach profile and the beach. 219 00:13:31,066 --> 00:13:33,666 The beach itself has different names back here. 220 00:13:33,666 --> 00:13:37,216 This is the Fore Dune, the first thing dune that you see here, 221 00:13:37,599 --> 00:13:40,449 all of this is called the back shore. 222 00:13:40,449 --> 00:13:41,549 This sand here where Mr. Mullens 223 00:13:43,699 --> 00:13:43,949 is pounding his 224 00:13:43,949 --> 00:13:47,016 stakes is called the foreshore. 225 00:13:47,016 --> 00:13:50,715 You say where I be standing, if you're standing on a little ledge 226 00:13:50,899 --> 00:13:53,532 that slopes away behind her down to the water. 227 00:13:54,665 --> 00:13:57,399 Laurie, how about identifying the middle part of the back 228 00:13:57,399 --> 00:14:01,415 shore here? 229 00:14:01,415 --> 00:14:03,349 Okay, Now this is the this is the back. 230 00:14:03,349 --> 00:14:07,698 And you can see there is a slight slope from Laurie back here to the back 231 00:14:08,148 --> 00:14:09,682 at the base of the dune. 232 00:14:09,682 --> 00:14:14,532 Sara how about identifying where the base of that dune is? 233 00:14:15,732 --> 00:14:18,315 Any questions about the structures 234 00:14:18,315 --> 00:14:24,431 or anything that we've looked at here? 235 00:14:24,431 --> 00:14:27,531 The foredune Ridge is the first line of defense against storm 236 00:14:28,365 --> 00:14:30,581 sand blown by the wind from the berm 237 00:14:30,881 --> 00:14:33,231 crosses the beach to the vegetation line 238 00:14:34,281 --> 00:14:38,748 here, wind velocity diminishes and airborne sand tends to collect 239 00:14:40,698 --> 00:14:43,698 behind any plant which can survive the harsh conditions. 240 00:14:43,698 --> 00:14:46,281 At the edge of the beach, there's a wind shadow 241 00:14:47,348 --> 00:14:51,148 such hardy plants as these can cause enough sand to collect to form 242 00:14:51,164 --> 00:14:52,898 a small dune. 243 00:14:52,898 --> 00:14:56,414 One of the hardiest plant species near the ocean is the sea oat 244 00:14:57,097 --> 00:15:00,997 because it can survive strong winds, salt and sandy soil. 245 00:15:01,281 --> 00:15:07,047 It is important to the formation and stability of dunes. 246 00:15:07,047 --> 00:15:10,580 See how all of this debris here is sea oat roots 247 00:15:11,264 --> 00:15:14,864 and the roots tend to stabilize the dune, the subsurface part of the dune 248 00:15:15,097 --> 00:15:18,014 and the top part of the growing part of the sea out 249 00:15:19,030 --> 00:15:21,797 traps Sand then the sea oats simply extends 250 00:15:21,797 --> 00:15:24,980 its spike up and grows right along with the dune. 251 00:15:25,397 --> 00:15:28,580 So it doesn't you know, it's not killed by the sand coming up around it. 252 00:15:28,580 --> 00:15:30,430 It just simply grows taller. 253 00:15:30,430 --> 00:15:34,747 So it keeps his head and its greenery up above the top of the sand, all the way 254 00:15:35,497 --> 00:15:38,347 up through here, you can see where the sand, 255 00:15:38,347 --> 00:15:41,230 the wind has blown and blown away that sand. 256 00:15:41,563 --> 00:15:43,030 Look at all of the streaks in there. 257 00:15:43,030 --> 00:15:45,730 That's the cross netting that I mentioned before. 258 00:15:45,730 --> 00:15:48,730 Which tells you a little bit about which direction the sand was coming 259 00:15:49,180 --> 00:15:54,313 or the wind was coming when it blew the sand away or blew it through there. 260 00:15:54,313 --> 00:15:59,929 Behind the remains of a storm wrecked fishing vessel Dune stand as lonely sentinel 261 00:16:02,746 --> 00:16:03,546 All the dunes 262 00:16:03,546 --> 00:16:07,146 you see on little Talbot were built by wind and wave action 263 00:16:07,363 --> 00:16:18,996 with the help of hardy vegetation. 264 00:16:18,996 --> 00:16:23,079 All dunes are temporary structures and could be destroyed 265 00:16:23,079 --> 00:16:36,395 by a severe northeaster or by a hurricane. 266 00:16:36,395 --> 00:16:39,579 In calmer weather, the shore of Little Talbot Island 267 00:16:39,579 --> 00:16:43,179 is the home and feeding ground of several species of bird. 268 00:16:44,795 --> 00:16:47,678 These brown pelicans have found a school of fish trapped 269 00:16:47,678 --> 00:16:52,428 by the falling tide between the shore and the sandbar. 270 00:16:52,428 --> 00:16:57,045 Another inhabitant of the beach, rarely seen in daylight hours, is the ghost crab. 271 00:16:57,462 --> 00:17:00,612 It is a marine animal and cannot stray far from the sea. 272 00:17:00,795 --> 00:17:03,378 The little crab 273 00:17:03,378 --> 00:17:05,378 has a burrow right here, and if you come out 274 00:17:05,378 --> 00:17:08,528 closely, you can see where it's been a little bit active. 275 00:17:09,045 --> 00:17:13,278 This isn't the best specimen for a burrow, because normally 276 00:17:13,478 --> 00:17:17,028 that little apron at the front is much more well developed, 277 00:17:17,211 --> 00:17:20,661 and that's kind of characteristic of a ghost crab burrow. 278 00:17:20,928 --> 00:17:23,561 They'll have a little apron of sand at around the front of it, 279 00:17:24,011 --> 00:17:27,344 but because of the storm, I think is probably why it's not the way 280 00:17:28,244 --> 00:17:29,961 not a prime example of it. 281 00:17:29,961 --> 00:17:33,794 But you can see his track to where he's come out all up and down here 282 00:17:34,394 --> 00:17:37,627 on the other side where we've been looking for food and so on. 283 00:17:38,261 --> 00:17:39,411 They have two big 284 00:17:40,361 --> 00:17:41,744 sensor claws 285 00:17:41,744 --> 00:17:45,044 that they use to collect their edible, 286 00:17:45,761 --> 00:17:49,310 but they're they're kind of a neat animal and they live in the backshore. 287 00:17:49,310 --> 00:17:51,944 It's typical backshore 288 00:17:52,477 --> 00:17:53,677 animal 289 00:17:54,677 --> 00:17:57,010 occasionally on cloudy days, such 290 00:17:57,010 --> 00:17:59,977 as today, we find these crabs on the beach, 291 00:18:00,310 --> 00:18:02,660 even though they're predominantly night hunters. 292 00:18:04,027 --> 00:18:06,527 This crab has his eye stalks fully 293 00:18:06,527 --> 00:18:09,710 extended, and its movements are rather defensive. 294 00:18:09,710 --> 00:18:12,610 In response to our presence, 295 00:18:12,610 --> 00:18:14,677 it has lost one of its claws, 296 00:18:14,677 --> 00:18:20,027 probably to a hostile relative. 297 00:18:20,027 --> 00:18:23,810 While the ghost crabs spends most of its time scavenging on the beach 298 00:18:23,810 --> 00:18:29,110 in its burrow, it must return periodically to the sea. 299 00:18:29,110 --> 00:18:32,076 It does not have lungs, and it must replenish water 300 00:18:32,076 --> 00:18:34,776 which is recirculated in a bronchial chamber. 301 00:18:36,010 --> 00:18:40,459 This crab is called the ghost crab because its pale yellow and white colors 302 00:18:40,693 --> 00:18:58,709 provide excellent camouflage. 303 00:18:58,709 --> 00:19:04,342 [Funky 304 00:19:04,342 --> 00:19:09,975 upbeat 305 00:19:09,975 --> 00:19:21,225 synth music] 306 00:19:21,225 --> 00:19:25,458 one word that can describe the true nature of a barrier island is change. 307 00:19:26,108 --> 00:19:29,258 Animals, which call these islands home, have learned to live 308 00:19:29,258 --> 00:19:35,225 in dynamic equilibrium. 309 00:19:35,225 --> 00:19:38,358 The ghost crab, for example, moves its burrow higher 310 00:19:38,358 --> 00:19:41,625 up the beach in response to the ever rising level of the sea. 311 00:19:43,325 --> 00:19:43,841 The island 312 00:19:43,841 --> 00:19:46,875 changes as sand is eroded and redeposited 313 00:19:47,708 --> 00:19:51,641 what was once marshland than sand dune is now the shoreline. 314 00:19:52,275 --> 00:19:54,975 What is, was and shall be as the forces 315 00:19:54,975 --> 00:19:57,974 of nature, wind, water and wave action 316 00:19:58,208 --> 00:20:01,874 continually reshape this tiny plot of land known 317 00:20:01,874 --> 00:20:40,924 as barrier island.