Dataset Information

Deep-Water Renewal Events; Insights into Deep Water Sediment Transport Mechanisms.

ABSTRACT: Deep-water renewal (DWR) events are characterized in the Strait of Georgia, Canada using 11 years of real-time physical and chemical oceanographic data and seafloor videos. At least 6 DWRs occur per year at 300?m water depth and each event continues for over 3 days. They initiate during neap tides and are associated with increased turbidity. In the spring, DWRs introduce cold, oxygenated and nutrient-poor waters, and in the fall they introduce warm, oxygen-depleted, nutrient-rich and saline waters. Although the timing and magnitude of DWRs differ from year to year, we demonstrate that they are not restricted to two seasons, but continue throughout the year. High-resolution videos of DWRs show that these events comprise a plume of high suspended sediment concentration that flows parallel to the basin axis and deposits approximately 1.5?cm per event.

SUBMITTER: Ayranci K

PROVIDER: S-EPMC7145800 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature

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Publications

Deep-Water Renewal Events; Insights into Deep Water Sediment Transport Mechanisms.

Ayranci K K Dashtgard S E SE

Scientific reports 20200409 1

Deep-water renewal (DWR) events are characterized in the Strait of Georgia, Canada using 11 years of real-time physical and chemical oceanographic data and seafloor videos. At least 6 DWRs occur per year at 300 m water depth and each event continues for over 3 days. They initiate during neap tides and are associated with increased turbidity. In the spring, DWRs introduce cold, oxygenated and nutrient-poor waters, and in the fall they introduce warm, oxygen-depleted, nutrient-rich and saline wate ...[more]

PMID: 32273562

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Project description:Magnetotactic bacteria (MTB) use passive alignment with the Earth magnetic field as a mean to increase their navigation efficiency in horizontally stratified environments through what is known as magneto-aerotaxis (M-A). Current M-A models have been derived from MTB observations in aqueous environments, where a >80% alignment with inclined magnetic field lines produces a one-dimensional search for optimal living conditions. However, the mean magnetic alignment of MTB in their most widespread living environment, i.e. sediment, has been recently found to be <1%, greatly reducing or even eliminating the magnetotactic advantage deduced for the case of MTB in water. In order to understand the role of magnetotaxis for MTB populations living in sediment, we performed first M-A observations with lake sediment microcosms. Microcosm experiments were based on different combinations of (1) MTB position with respect to their preferred living depth (i.e. above, at, and below), and (2) magnetic field configurations (i.e. correctly and incorrectly polarized vertical fields, horizontal fields, and zero fields). Results suggest that polar magnetotaxis is more complex than implied by previous experiments, and revealed unexpected differences between two types of MTB living in the same sediment. Our main findings are: (1) all investigated MTB benefit of a clear magnetotactic advantage when they need to migrate over macroscopic distances for reaching their optimal living depth, (2) magnetotaxis is not used by all MTB under stationary, undisturbed conditions, (3) some MTB can rely only on chemotaxis for macroscopic vertical displacements in sediment while other cannot, and (4) some MTB use a fixed polar M-A mechanisms, while other can switch their M-A polarity, performing what can be considered as a mixed polar-axial M-A. These observations demonstrate that sedimentary M-A is controlled by complex mechanical, chemical, and temporal factors that are poorly reproduced in aqueous environments.

Dataset Information

Deep-Water Renewal Events; Insights into Deep Water Sediment Transport Mechanisms.

Publications

Deep-Water Renewal Events; Insights into Deep Water Sediment Transport Mechanisms.

Similar Datasets

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