It takes a long time to grow a big coral colony or a coral reef, because each coral grows slowly. The fastest corals expand at more than 6 inches 15 cm per year, but most grow less than an inch per year. Reefs themselves grow even more slowly because after the corals die, they break into smaller pieces and become compacted. Individual colonies can often live decades to centuries, and some deep-sea colonies have lived more than 4000 years. One way we know this is because corals lay down annual rings, just as trees do. These skeletons can tell us about what conditions were like hundreds or thousands of years ago. The Great Barrier Reef as it exists today began growing about 20,000 years ago.
圖片編號:
110583556
拍攝者:
Chriskiely
點數下載
授權類型 | 尺寸 | 像素 | 格式 | 點數 | |
---|---|---|---|---|---|
標準授權 | XS | 480 x 360 | JPG | 13 | |
標準授權 | S | 800 x 600 | JPG | 15 | |
標準授權 | M | 2000 x 1500 | JPG | 18 | |
標準授權 | L | 3048 x 2286 | JPG | 20 | |
標準授權 | XL | 3265 x 2449 | JPG | 22 | |
標準授權 | MAX | 4000 x 3000 | JPG | 23 | |
標準授權 | TIFF | 4311 x 3233 | TIF | 39 | |
進階授權 | WEL | 4000 x 3000 | JPG | 88 | |
進階授權 | PEL | 4000 x 3000 | JPG | 88 | |
進階授權 | UEL | 4000 x 3000 | JPG | 88 |
XS
S
M
L
XL
MAX
TIFF
WEL
PEL
UEL
標準授權 | 480 x 360 px | JPG | 13 點 |
標準授權 | 800 x 600 px | JPG | 15 點 |
標準授權 | 2000 x 1500 px | JPG | 18 點 |
標準授權 | 3048 x 2286 px | JPG | 20 點 |
標準授權 | 3265 x 2449 px | JPG | 22 點 |
標準授權 | 4000 x 3000 px | JPG | 23 點 |
標準授權 | 4311 x 3233 px | TIF | 39 點 |
進階授權 | 4000 x 3000 px | JPG | 88 點 |
進階授權 | 4000 x 3000 px | JPG | 88 點 |
進階授權 | 4000 x 3000 px | JPG | 88 點 |