Potholes in Jurassic sandstone (upper Ute Canyon overlook, Colorado National Monument, Colorado, USA) 3 : 無料・フリー素材/写真
Potholes in Jurassic sandstone (upper Ute Canyon overlook, Colorado National Monument, Colorado, USA) 3 / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
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| 説明 | Potholes on a Jurassic sandstone surface in Colorado, USA.Colorado National Monument is a colorful and scenic park just southwest of the town of Grand Junction in western Colorado, USA. It's located in the northeastern part of the Colorado Plateau Physiographic Province, a large section of continental crust that was significant uplifted during the Cenozoic. The rocks in the park are gently folded into a large monocline that has been erosionally dissected into a series of dramatic canyons.After rain events, the depressions shown above get filled or partially filled with water. In a desert setting like Colorado National Monument, the water evaporates relatively quickly, on time scales from hours to weeks, depending on the depth of the depression and the depth of the water. Organisms that live in or occupy these water-filled potholes include bacteria, algae, gastropods (snails), branchiopod crustaceans (anostracans - "fairy shrimp" and notostracans - "tadpole shrimp"), pothole mites, and spadefoot toads.--------------Info. from park signage:"Shallow pools of rainwater called "potholes" are common where bare sandstone is exposed to rainfall. These extreme aquatic environments may only be wet for a few days but amazing transformations can happen overnight.""Different species have different survival strategies to deal with evaporating water. Species that can leave the pool like the spadefoot toad move to a new water source. For crustaceans who can't leave as the water evaporates, like the fairy shrimp, the strategy is to lay eggs that survive being dry. Shrimp substitute sugars for water in the eggs they produce, which acts like a kind of antifreeze. The eggs can survive for decades and be revitalized by a rainstorm. Bacteria and algae living in the potholes also use this strategy. [S]ome species take a "tupperware" strategy, sealing themselves up with some water until it rains again. Some species of water snail use this approach as well as pothole mites."---------------Locality: upper Ute Canyon overlook, Colorado National Monument, southwest of the town of Grand Junction, west-central Mesa County, far-western Colorado, USA |
| 撮影日 | 2013-06-12 14:39:42 |
| 撮影者 | James St. John |
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