漂浮在南极半岛西部海域的拱形冰山, 南大洋 Arched iceberg floating off the western Antarctic Peninsula, Southern Ocean (© Steven Kazlowski/Nature Picture Library)

漂浮在南极半岛西部海域的拱形冰山, 南大洋 Arched iceberg floating off the western Antarctic Peninsula, Southern Ocean (© Steven Kazlowski/Nature Picture Library)

海洋中冰封的大教堂 An ocean's frozen cathedral

南极半岛西部，南大洋，拱形冰山

在南极半岛沿岸，一道冰雕般的拱形结构从南大洋拔地而起，而南极半岛是地球上变暖速度最快的地区之一。这道拱形结构最初是由积雪压实而成，历经数千年演变为冰川。最终，冰川或漂浮冰架的一部分断裂脱落——这一过程被称为冰崩——形成了漂浮的冰山。

冰山按大小和形状分类。要符合冰山的定义，冰山的高度必须超过海平面约16英尺（约4.9米），但其近90%仍隐藏在水面之下。顶部平坦的“板状”冰山在南极洲很常见，而像图中这种拱形冰山则属于不规则的非板状冰山。

这些看似荒芜的漂浮巨物，实则孕育着生命。藻类附着在它们的底部，为成群的磷虾提供食物，而磷虾又为鱼类、海豹和鲸鱼提供养分。随着冰层融化，释放出的营养物质滋养着周围的水域，使这些冰雕变成了移动的生态系统。

Arched iceberg, western Antarctic Peninsula, Southern Ocean

A sculpted arch of ice rises from the Southern Ocean along the Antarctic Peninsula, one of the fastest-warming regions on Earth. This formation began as compacted snow that turned into glacial ice over thousands of years. Eventually, part of a glacier or floating ice shelf fractured and broke free—a process known as calving—creating a drifting iceberg.

Icebergs are classified by size and shape. To qualify, a mass must tower more than about 16 feet above sea level, yet nearly 90% of it remains hidden below the surface. Flat-topped 'tabular' forms are common in Antarctica, while eroded features like this arch fall into irregular, non-tabular categories.

Though seemingly barren, these floating giants support life. Algae cling to their undersides, feeding swarms of krill, which sustain fish, seals, and whales. As ice melts, it releases nutrients that fertilize surrounding waters, turning these frozen sculptures into mobile ecosystems.