62 Life in the Current-Mid

Life in the Current FOCUS Question How does the East Australian Current support living things?

当前生活焦点问题东澳大利亚洋流如何支持生物?

Rivers in the Ocean In the movies, a young fish may hitch a ride with a sea turtle and ride a current to zip through the ocean. Ocean currents are like huge rivers flowing within a larger body of water. They move in regular patterns around the ocean. Currents at the surface are caused by wind and by Earth's rotation. Real animals ride on ocean currents including on the "movie star" known as the East Australian Current (EAC).

海洋中的河流在电影中，一条年轻的鱼可能会搭上海龟的便车，乘着洋流在海洋中穿行。 洋流就像在更大的水体中流动的巨大河流。 它们在海洋中有规律地移动。 地表的洋流是由风和地球自转引起的。 真正的动物在洋流上航行，包括被称为东澳大利亚洋流(EAC)的“电影明星”。

Speedway of the South Pacific The EAC is a lot like a current in the Atlantic Ocean called the Gulf Stream (see map on page 2). Both currents are fast-flowing and bring warm, tropical water to cooler water regions. The EAC zips through the Pacific Ocean at up to 177 kilometers (110 mi.) per day. This current flows near the ocean's surface. It begins in the warm, tropical Coral Sea. From there, it sweeps south along the east coast of Australia. It ends in the Tasman Sea, where it mixes with the sea's cooler waters. Both the Gulf Stream and the EAC are part of complete circles of ocean currents called gyres (see map on page 2). As these strong currents flow, swirling loops of water called eddies break off from the main current. Math Moment The Gulf Stream moves at speeds of up to 216 kilometers (134 mi.) per day Which current is faster, the EAC or the Gulf Stream? How much faster?

南太平洋的高速公路EAC很像大西洋中被称为墨西哥湾流的洋流(见第2页地图)。 这两种水流都是快速流动的，将温暖的热带海水带到较冷的水域。 EAC以每天177公里(110英里)的速度穿过太平洋。 洋流在海洋表面附近流动。 它始于温暖的热带珊瑚海。 从那里，它沿着澳大利亚东海岸向南移动。 它的终点是塔斯曼海，在那里它与海中较冷的海水混合。 墨西哥湾流和EAC都是称为环流的完整洋流圈的一部分(见第2页的地图)。 当这些强水流流过时，漩涡状的水环就会从主水流中分离出来。 墨西哥湾流每天的移动速度可达216公里(134英里)，EAC和墨西哥湾流哪个水流更快? 快了多少?

Come Up for a Meal Where eddies form, the ocean comes alive! When an eddy breaks off from the main current, it drifts into cooler water. As the warm eddy swirls, cold water from deeper in the ocean is pulled up in a process called upwelling. Deep, cold water is rich with nutrients, minerals, and other living things. Cold water, holds more oxygen than warm water, and since organisms need oxygen, they are plentiful in areas with cold water. As a result, the number of living things is higher in areas of upwelling. Up at the surface, these living things provide abundant food for fish and other ocean creatures of the EAC.

在涡流形成的地方，海洋变得活跃起来!当一个涡流脱离主水流时，它就会漂流到较冷的水中。 当暖涡旋转时，来自海洋深处的冷水被拉上来，这一过程被称为上升流。 深而冷的海水富含营养物质、矿物质和其他生物。 冷水比温水含有更多的氧气，因为生物需要氧气，所以冷水地区有大量的生物。 因此，上升流地区的生物数量较多。 在海面上，这些生物为鱼类和EAC的其他海洋生物提供了丰富的食物。

Catch a Ride The EAC is fastest and strongest in spring and summer. That's when its powerful flow sweeps up thousands of living things. They leave their homes in the warm Coral Sea to catch a ride on the current and head south to the cooler waters off Australia's southeast coast. These northern "tourists" include colorful reef butterfly fish. They also include humpback whales, eastern rock lobsters, and tiny plankton. Some fish and other ocean organisms, such as lobsters and sea stars, use the EAC to spread their larvae far down the coast. The babies find new habitats where they can grow up.

春季和夏季的EAC是最快最强的。 这时它强大的水流会卷走成千上万的生物。 他们离开温暖的珊瑚海的家，乘着洋流向南前往澳大利亚东南海岸更凉爽的水域。 这些北方的“游客”包括五颜六色的礁蝶鱼。 它们还包括座头鲸、东部岩龙虾和微小的浮游生物。 一些鱼类和其他海洋生物，如龙虾和海星，利用EAC将它们的幼虫传播到很远的海岸。 幼崽们会找到新的栖息地，在那里成长。

Go with the Flow Sea turtles also ride the EAC— and not just in the movies! Baby loggerhead turtles hatch from eggs laid on beaches in northeastern Australia. While still tiny, they crawl into the sea and ride the EAC south. Soon the current swings east, away from the coast, and joins the South Pacific Gyre. The tiny turtles go with the flow. Caught in the current, the turtles shoot across the vast Pacific toward South America. As they become adults, they circle back to Australia by riding other currents in the South Pacific Gyre. There, they hit the beach again to nest and lay eggs of their own.

海龟也会乘坐EAC，而且不只是在电影中!在澳大利亚东北部的海滩上，红海龟宝宝从产卵中孵化出来。 在它们还很小的时候，它们就爬进海里，沿着EAC向南行驶。 很快，洋流向东漂移，远离海岸，加入南太平洋环流。 小海龟们随波逐流。 海龟们被困在洋流中，穿过广阔的太平洋，直奔南美洲。 成年后，它们会沿着南太平洋环流的其他洋流绕回澳大利亚。 在那里，它们再次来到海滩筑巢并产卵。