Inorganic mineral flocculation within mid-to-high latitude deep coastal basins

IF 2.6 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Marine Geology Pub Date : 2026-01-01 Epub Date: 2025-10-28 DOI:10.1016/j.margeo.2025.107675

Jaia Syvitski , Ross Powell , Kumiko Azetsu-Scott , Ken Asprey , Eric Hutton , Gywn Lintern

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引用次数: 0

Abstract

Flocculation dynamics of inorganic mineral grains are quantified for ten mid-to-high latitude, deep coastal basins along the Atlantic, Pacific and Southern Oceans. Suspended floc populations are imaged in situ, capturing an undisturbed water column. The basins receive and accumulate low carbon sediment via delivery of inorganic mineral flocs that carry a reactive organic carbon component during transport. Suspended particles are distributed among four particle reservoirs each characterized by a settling velocity (w) and floc size (D): 1) microflocs and constituent grains (D < 50 μm, w < 4 m/day); 2) medium size flocs (D = 50 to 650 μm, w = 4 to 32 m/day; 3) large flocs (D = 650–5000 μm, w = 32 to 172 m/day); and 4) strings of flocs (5–100 mm in length, w = 200 to 400 m/day) sometimes forming “fabrics”. Stratified currents control flocculation by providing the necessary conditions to support bio-mediated inorganic flocculation. A multi-layer classification scheme based on vertical trends in floc concentration and diameter is used to identify hotspots of flocculation growth and decay within a suite of particle layers: 1) surface layers, 2) flocculation fronts, 3) dilution layers, 4) steady-state layers, 5) deep basin waters, 6) bottom boundary layers, and 7) shelf nepheloid layers. Flocculation fronts form along oceanographic sill depths carrying shear turbulence, and similarly along brackish to seawater mixing depths. Once flocs enter deep basin waters, their properties change little during sedimentation. Transit time for flocs to reach a basin's seafloor ranged from 1 to 14 days for basin depths 73 to 873 m. Evidence suggests multiple aggregation processes (e.g. doubling, onion skin, chaos) can act simultaneously within basin waters. Insights from this study can inform environmental management, such as mitigating the effects of sedimentation from human activities and understanding the implications of climate change on fjord ecosystems.

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中高纬度深海岸盆地内无机矿物絮凝作用

对大西洋、太平洋和南大洋沿岸10个中高纬度深海岸盆地的无机矿物颗粒絮凝动力学进行了定量研究。悬浮浮群在原地成像，捕捉未受干扰的水柱。盆地通过输送无机矿物絮凝体来接收和积累低碳沉积物，这些絮凝体在运输过程中携带活性有机碳成分。悬浮颗粒分布在4个颗粒库中，每个颗粒库的沉降速度（w)和粒径(D)分别为：1）微絮凝体和组成颗粒（D < 50 μm, w < 4 m/ D）；2)中型絮凝体（D = 50 ~ 650 μm, w = 4 ~ 32 m/ D）； 3)大型絮凝体（D = 650 ~ 5000 μm, w = 32 ~ 172 m/ D）；4)絮凝体串（长度5-100毫米，w = 200 - 400米/天）有时形成“织物”。分层电流通过为支持生物介导的无机絮凝提供必要的条件来控制絮凝。采用基于絮凝体浓度和粒径垂直趋势的多层分类方案，在一组颗粒层中识别絮凝生长和衰减热点：1)表层，2)絮凝锋，3)稀释层，4)稳态层，5)深盆地水域，6)底边界层，7)陆棚网状层。絮凝锋沿着带剪切湍流的海洋静止深度形成，类似地沿着咸淡水到海水混合深度形成。一旦絮凝体进入深盆地水域，它们的特性在沉积过程中几乎没有变化。在盆地深度为73 - 873 m的情况下，絮凝体到达盆地海底的运输时间为1 - 14天。有证据表明，多个聚集过程（如加倍、洋葱皮、混乱）可以同时在盆地水域内发生作用。这项研究的见解可以为环境管理提供信息，例如减轻人类活动造成的沉积影响，以及了解气候变化对峡湾生态系统的影响。

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来源期刊

Marine Geology 地学-地球科学综合

CiteScore

6.10

自引率

6.90%

发文量

175

审稿时长

21.9 weeks

期刊介绍： Marine Geology is the premier international journal on marine geological processes in the broadest sense. We seek papers that are comprehensive, interdisciplinary and synthetic that will be lasting contributions to the field. Although most papers are based on regional studies, they must demonstrate new findings of international significance. We accept papers on subjects as diverse as seafloor hydrothermal systems, beach dynamics, early diagenesis, microbiological studies in sediments, palaeoclimate studies and geophysical studies of the seabed. We encourage papers that address emerging new fields, for example the influence of anthropogenic processes on coastal/marine geology and coastal/marine geoarchaeology. We insist that the papers are concerned with the marine realm and that they deal with geology: with rocks, sediments, and physical and chemical processes affecting them. Papers should address scientific hypotheses: highly descriptive data compilations or papers that deal only with marine management and risk assessment should be submitted to other journals. Papers on laboratory or modelling studies must demonstrate direct relevance to marine processes or deposits. The primary criteria for acceptance of papers is that the science is of high quality, novel, significant, and of broad international interest.