The São Paulo Ridge (SPR) is a 350 km-long linear geological feature located in the Continental Margin off Brazil (Latitude 28–29°S, Longitude 40–45°W). In 2013, the region was mapped during the SW Atlantic “Iata-Piuná” expedition and explored by a series of deep-sea dives of the manned submersible Shinkai 6500. A digital bathymetric model analyzed for seafloor morphology, delimited four major bathymetric sectors namely plateau, ridge crest, ridge escarpment and ridge foot. These sectors further enclosed 12 morphological features at smaller spatial scales (structural classes) including plains, valleys, peaks, terraces, and troughs. Video profiles across the depth gradient (4,219–2,644 m depths) revealed that the slopes of the SPR southern flank were gentle and terraced, mostly covered by biogenic sediments and interrupted by rocky cliffs/crests, dispersed outcrops and loose particles. The North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW) overlaid at the escarpment along which they established colder (0.4–1.0°C; 4,200–3,400 m) and warmer (2.0–3.0°C; 3,400–2,600 m) habitats, respectively. Physical components were used to define seven seascape units in the ridge foot (2), escarpment (3), and plateau-ridge crest (2), where a total of 914 organisms of the epibenthic and benthopelagic megafauna were recorded. Over 70% of these records were sessile suspension feeders, including sponges (61.5%) and anthozoans (11.4%). Most taxonomic groups concentrated above 3,800 m, under the influence of NADW, where densities reached maximum values (mean 0.26 organisms.m–2; 0.024–0.027 organisms.m2 95% CI). Also, nearly half of megafauna records concentrated in patches delimited by the 3,800–3,300 m and 2,900–2,700 m isobaths. The deepest patch (3800–3300 m) coincided with the interface zone between AABW and NADW, where mixing processes create a density gradient. Evidences suggested that topography-related deep-water flow dynamics, and not substrate availability, drives benthic megafauna distribution at meso-habitat scale.

中文翻译：

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大西洋西南部圣保罗山脊斜坡上的深海栖息地和巨型动物群

圣保罗海岭 (SPR) 是一个 350 公里长的线性地质特征，位于巴西大陆边缘（南纬 28-29°，西经 40-45°）。2013 年，该地区在西南大西洋“Iata-Piuná”探险期间被绘制出来，并通过载人潜水器新海 6500 的一系列深海潜水进行了探索。 一个分析海底形态的数字测深模型，划定了四个主要的测深扇区，即高原、岭嵴、岭崖和岭脚。这些扇区在较小的空间尺度（结构类）上进一步包含了 12 个形态特征，包括平原、山谷、山峰、阶地和海槽。跨深度梯度（4,219-2,644 m 深度）的视频剖面显示，SPR 南翼的斜坡是平缓的梯田，大部分被生物沉积物覆盖，并被岩石峭壁/波峰打断，分散的露头和松散的颗粒。北大西洋深水 (NADW) 和南极底水 (AABW) 覆盖在悬崖上，沿悬崖形成较冷 (0.4–1.0°C; 4,200–3,400 m) 和较暖 (2.0–3.0°C; 3,400–2,600 m)栖息地，分别。物理组件用于定义山脊脚 (2)、悬崖 (3) 和高原山脊顶 (2) 的七个海景单元，共记录了 914 种底栖动物和底栖动物群的生物。这些记录中超过 70% 是无柄悬浮饲养者，包括海绵 (61.5%) 和珊瑚虫 (11.4%)。大多数分类群集中在 3,800 m 以上，在 NADW 的影响下，密度达到最大值（平均 0.26 个生物体.m-2；0.024-0.027 个生物体.m2 95% CI）。此外，近一半的巨型动物记录集中在由 3,800-3, 300 m 和 2,900–2,700 m 等深线。最深的斑块 (3800-3300 m) 与 AABW 和 NADW 之间的界面区域重合，混合过程在此处产生密度梯度。有证据表明，与地形相关的深水流动力学，而不是基质可用性，驱动了中观栖息地尺度的底栖巨型动物分布。