Chilean Patagonia is one of the few regions in the Southern Hemisphere where tidewater glaciers deliver torrential meltwater. We sampled the Beagle Channel and five tributary fjords, with and without glaciers, to explore modern foraminifera of this little studied region. Surface sediments (mud, sand, pebbles, and shell debris) were collected at 45 stations from water depths 15 to 250 m, along with four short cores. The soft bottom recovered at 35 stations was analyzed for grain size, Loss-on-ignition reflecting content of organic matter, and Rose-Bengal-stained foraminifera. The benthic fauna consisted of 86 attached and free-living species. Uvigerina bifurcata, Alveolophragmium orbiculatum, Ammobaculites americanus, Stainforthia fusiformis, Globobulimina notovata, and Nonionoides grateloupii were dominant. As shown by downcore distribution, U. bifurcata and A. orbiculatum occupied epifaunal and G. notovata and S. fusiformis infaunal microhabitats. Distribution of the dominant foraminifera showed no clear pattern, with the exception of S. fusiformis, which formed a monospecific assemblage in sediments enriched with organic matter. Certain subdominant species, including Cassidulinoides parkerianus, Pullenia subcarinata, and Cibicides fletcheri, showed environmental affinity to more sandy sediments, whereas the assemblage from more muddy sediments had no inherent taxa. Foraminiferal standing crop in size fraction >125 μm was mostly 100 to 500 specimens per 10 cm³ but dropped to <1 specimen near glacier fronts, where foraminifera varied greatly between stations and did not constitute a single, unified assemblage. This patchy pattern seems to result from environmental instability caused by rapidly settling mineral fines and from random dispersal and activation of propagules. It helps to interpret records of other meltwater-dominated events.

智利巴塔哥尼亚是南半球为数不多的潮水冰川输送倾泻融水的地区之一。我们对有和没有冰川的比格尔海峡和五个支流峡湾进行了采样，以探索这个研究较少的地区的现代有孔虫。在水深 15 至 250 米的 45 个站点收集了表层沉积物（泥浆、沙子、鹅卵石和贝壳碎片）以及四个短岩心。分析了在 35 个站点回收的软底的粒度、反映有机物含量的烧失量和玫瑰红染色的有孔虫。底栖动物群包括 86 种附着和自由生活的物种。Uvigerina bifurcata , Alveolophragmium orbiculatum , Ammobaculites americanus , Stainforthia fusiformis, Globobulimina notovata和Nonionoides grateloupii占优势。如 downcore 分布所示，U. bifurcata和A. orbiculatum占据了表层动物，G. notovata和S. fusiformis占据了动物区系微生境。主要有孔虫的分布没有明确的模式，除了S. fusiformis，它在富含有机质的沉积物中形成单一特异性组合。某些亚优势种，包括Cassidulinoides parkerianus、Pullenia subcarinata和Cibicides fletcheri，显示出对更多沙质沉积物的环境亲和力，而来自更多泥质沉积物的组合没有固有的分类群。尺寸分数 >125 μm 的有孔虫现存作物大多为每 10 cm ³ 100 到 500 个标本，但在冰川前缘附近下降到 <1 个标本，那里的有孔虫在不同站点之间差异很大，并不构成单一、统一的组合。这种斑驳的模式似乎是由快速沉降的矿物细粒和繁殖体的随机扩散和激活引起的环境不稳定造成的。它有助于解释其他以融水为主的事件的记录。