Timelapse photos of Johns Hopkins Inlet iceberg habitat, Glacier Bay National Park, Alaska, 2021

Data are available at: https://arcticdata.io/data/10.18739/A2W08WH8M Tidewater glacier fjords are highly dynamic environments that are affected by several glaciological and oceanographic processes: (i) subglacial discharge creates upwelling plumes that drive estuarine circulation and promote submarine melting of glaciers and icebergs, (ii) iceberg calving, which is affected by submarine melting, is a stochastic energy source that mixes near-glacier waters and produces waves that crash on shore and cause icebergs to capsize, and (iii) motion of icebergs and fjord waters are affected by winds, tides, and subglacial discharge. Numerous species reside in tidewater glacier fjords, including harbor seals, which seasonally aggregate in fjords and use ice habitat for critical life functions including pupping, molting, and foraging. Seals that haul-out on icebergs during the pupping and molting seasons take longer and deeper dives for feeding than those that use terrestrial haul-outs, but may acquire higher quality food. Additionally, icebergs do not flood during high tide, which increases the amount of time that seals can remain hauled-out and that pups can spend nursing, thus increasing energetic intake. Many basic questions remain unanswered, and the energy costs of coping with a constantly evolving landscape are unknown. This project addresses these deficiencies by investigating the temporal and spatial variability of seal habitat in Johns Hopkins Inlet, Glacier Bay, by synthesizing aerial surveys with high-rate time-lapse photogrammetry. This dataset consists of high-rate (1 photo per minute) time-lapse photos of Johns Hopkins Inlet that were acquired in summer 2021, at the coordinates of the camera locations.

数据集可获取于：https://arcticdata.io/data/10.18739/A2W08WH8M。潮汐冰川峡湾（tidewater glacier fjords）属于高度动态的环境，受多种冰川学与海洋学过程影响：(i) 冰下径流（subglacial discharge）会形成上升流羽流（upwelling plumes），驱动河口环流（estuarine circulation）并加速冰川与冰山的海底消融（submarine melting）；(ii) 受海底消融影响的冰山崩解（iceberg calving）是一种随机能量源，会混合冰川近岸水域，并产生拍击岸线的海浪，引发冰山倾覆；(iii) 冰山与峡湾水体的运动则受风力、潮汐与冰下径流的影响。

潮汐冰川峡湾中栖息着众多物种，其中港海豹（harbor seals）会季节性聚集于峡湾内，并利用冰生境完成产仔、换毛与觅食等关键生命活动。在产仔与换毛季选择在冰山上栖息的港海豹，相较于选择陆地栖息的个体，其觅食潜水时长更长、潜水深度更深，但可能获取到品质更高的食物。此外，涨潮时冰山不会被潮水淹没，这延长了港海豹的栖息时长与幼崽的育幼时间，进而提升了它们的能量摄入。

目前仍有诸多基础问题尚未得到解答，应对持续变化的环境所需的能量消耗也尚不明确。本项目通过结合航空调查与高速延时摄影测量（high-rate time-lapse photogrammetry）技术，对冰川湾（Glacier Bay）约翰斯·霍普金斯湾内港海豹栖息地的时空变异性展开研究，以此弥补上述研究空白。本数据集包含2021年夏季于相机站位坐标处采集的约翰斯·霍普金斯湾高速延时摄影照片，拍摄频率为每分钟1张。