Coral reefs around the world are in danger. The problem is that rising ocean temperatures are causing coral bleaching, which kills the colorful algae that live inside coral. Without these algae, coral turns white and eventually dies. This affects thousands of fish species that depend on reefs for food and shelter.
Scientists are working on several solutions. One approach is growing coral in nurseries and then transplanting it to damaged reefs. Another solution involves creating "super corals" that can survive warmer waters. Some communities have also established marine protected areas where fishing and pollution are limited. These efforts give hope that coral reefs can recover.
Hurricanes develop through a specific process. First, warm ocean water heats the air above it, causing the air to rise rapidly. Next, as this warm, moist air rises, it creates an area of low pressure near the ocean surface. Then, more air rushes in to fill this low-pressure area, and it too begins to rise and spin due to Earth's rotation.
As the storm continues to develop, the spinning winds grow stronger. Finally, when wind speeds reach 74 miles per hour, the storm officially becomes a hurricane. The entire process, from a small tropical disturbance to a powerful hurricane, can take several days.
Energy sources can be divided into two categories: renewable and nonrenewable. Renewable energy comes from sources that can be replaced naturally, such as sunlight, wind, and water. In contrast, nonrenewable energy comes from sources that take millions of years to form, like coal, oil, and natural gas.
Both types of energy have advantages and disadvantages. Renewable energy is cleaner for the environment; however, it can be more expensive to set up. Nonrenewable energy is currently cheaper and more widely available, but it produces pollution and will eventually run out. Unlike renewable sources that can last forever, nonrenewable resources are limited.