Autosub Science Missions
Science Mission 2
Dissolved and particulate manganese and oxygen in the water column of
the upper basins of two hypoxic sea lochs.
Loch Etive and Loch Fyne on the west coast of Scotland consist of a series of basins separated by shallow sills. The outer basins experience estuarine circulation whilst the innermost and deepest basins experience infrequent water renewal leading to hypoxia (low levels of oxygen) in the bottom waters.
The manganese cycle
Hypoxia, in the lochs, allows a build-up of both solid phase (authigenic) manganese (IV) and dissolved (pore-water) manganese (II) in the sediment. The dissolved manganese is able to diffuse into the overlying water column where it can be slowly oxidised, into insoluble manganese (IV). This, in turn, then precipitates to the sediment where it becomes buried and is reduced to soluble manganese(II), thus completing the cycle.
Why use Autosub?
The development of Autosub provided a unique, highly versatile submersible platform with which to determine the concentrations of dissolved and particulate manganese and dissolved oxygen throughout two sea lochs. This utilised the ability of Autosub to follow the terrain or to maintain a pre-set depth.
Related publications
Overnell J., Brand T., Bourgeois W. and Statham P.J., 2002. Manganese dynamics in the water column of the upper basin of Loch Etive, a Scottish fjord. Estuarine, Coastal and Shelf Science, 55(3), 481-492.
Related Autosub pages at BODC
| Autosub Science Missions | Science
Mission 4 Submersible single cell and particle analysis |
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| Science
Mission 1 Flow over sills in the Strait of Sicily | Science
Mission 5 Spatial variability of bottom turbulence over a sandbank |
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| Science
Mission 3 Under sea-ice and pelagic surveys | Science
Mission 6 Sonar and turbulence studies of the upper ocean |
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| Autosub Science Missions CDROM |
