正在确认阅读权限…
Caspian Sea: A Landlocked Body with Marine Characteristics
里海到底是湖还是海
精读先不看文字，完整听一遍。
-
The Caspian Sea is Earth’s largest inland body of water, covering 371,000 square kilometers but lacking oceanic connection.里海是地球上最大的内陆水体，面积达37.1万平方公里，但与海洋无直接连通。
-
Its salinity averages 1.2%, one-third that of seawater, varying from fresh near Volga inflows to brackish in southern basins.其平均盐度为1.2%，仅为海水的三分之一，从伏尔加河入湖处的淡水逐渐过渡到南部盆地的微咸水。
-
Tectonic origin distinguishes it from lakes—it sits in a remnant oceanic basin formed by the collision of Arabian and Eurasian plates.里海具有构造起源，区别于普通湖泊——它位于阿拉伯板块与欧亚板块碰撞形成的残余洋盆中。
-
Unlike true lakes, it has marine species like sturgeon and endemic plankton adapted to fluctuating salinity and pressure gradients.与真正的湖泊不同，里海拥有鲟鱼等海洋物种及适应盐度和压力梯度变化的特有浮游生物。
-
Sea-level changes—up to three meters since the 1970s—reflect climate-driven evaporation and altered river inputs from the Volga and Ural.自20世纪70年代以来，海平面变化达3米，反映出气候驱动的蒸发加剧及伏尔加河、乌拉尔河径流改变。
-
Oil and gas platforms operate offshore using marine drilling standards, though jurisdiction falls under littoral state treaties rather than UNCLOS.海上油气平台按海洋钻探标准作业，但管辖权归属沿岸国条约，而非《联合国海洋法公约》。
-
Sediment cores reveal ancient marine fossils, confirming its Pliocene connection to the Paratethys Sea before isolation.沉积岩芯揭示出远古海洋化石，证实其在上新世曾与副特提斯海相连，后因隔离而形成。
-
Its stratified water column features oxygen-rich surface layers and anoxic deep basins over 1,000 meters deep.其水体呈分层结构：表层富氧，深层超1000米的盆地则缺氧。
-
Coastal management requires transnational coordination because shoreline erosion in Turkmenistan affects sediment supply to Kazakh deltas.海岸管理需跨国协调，因土库曼斯坦的岸线侵蚀会影响沉积物向哈萨克斯坦三角洲的输送。
-
Geographers classify it as a 'sea' functionally due to size, hydrodynamics, and biogeography—even if legally defined as a lake by some states.地理学家基于其面积、水动力特征和生物地理特性，将其功能上归类为‘海’——尽管部分国家在法律上将其定义为湖泊。
精读 · 大约 10 分钟
听 → 读 → 学表达 → 懂 → 今天会说这一句 → 跟读录音 → 自己说一句。
③ 学 · 重点表达
- Sediment cores reveal ancient marine fossils, confirming its Pliocene connection to the Paratethys Sea before isolation. 沉积岩芯揭示出远古海洋化石，证实其在上新世曾与副特提斯海相连，后因隔离而形成。
- Its stratified water column features oxygen-rich surface layers and anoxic deep basins over 1,000 meters deep. 其水体呈分层结构：表层富氧，深层超1000米的盆地则缺氧。
- Coastal management requires transnational coordination because shoreline erosion in Turkmenistan affects sediment supply to Kazakh deltas. 海岸管理需跨国协调，因土库曼斯坦的岸线侵蚀会影响沉积物向哈萨克斯坦三角洲的输送。
④ 懂 · 选一选
⑤ 今天会说这一句
Sediment cores reveal ancient marine fossils, confirming its Pliocene connection to the Paratethys Sea before isolation.
⑥ 跟读并录音
Sediment cores reveal ancient marine fossils, confirming its Pliocene connection to the Paratethys Sea before isolation.
第一版：录下来、回听、再听标准音。系统打分以后再加。
⑦ 说 · 自己来一句
用今天的表达，自己说一句。
例子：Sediment cores reveal ancient marine fossils, confirming its Pliocene connection to the Paratethys Sea before isolation.
已记下。连续天数以后会显示在课表里。
陈老师指导
课程开发中，敬请期待。成人和孩子都可以先自学听读、精读。
这边的讲解音轨还在做。想先跟着老师走完固定 30 课，可以去陈老师带读社（和自学通行不是同一份会员）。
课程开发中，敬请期待。