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<div>Dear All,</div>
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<div>A request has come in to extend the L131 vocabulary to include something suitable for zoobethos (animals living on the surface of the seabed (or shore or intertidal zone) or just below it). </div>
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<div>We currently have a term:</div>
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<div>‘soil and sediment’ defined as ‘The unlithified sediments that form a layer between the solid crust and either the atmosphere or the water column.’</div>
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<div>Some confusion has arisen with the term ‘sediment’ being interpreted as mud or sand, whereas no limitation of grain size was intended. Consequently , I propose clarifying the definition to ‘The unlithified sediments (of any grain size from silt to boulders)
that form a layer between the solid crust and either the atmosphere or the water column.’</div>
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<div>Next we come to its boundary layer, which we could implement as a single term called ‘soil and sediment boundary’ and defined as ‘The upper surface (interface plus surficial substrate) of the layer of unlithified sediments (of any grain size from silt
to boulders) that form a layer between the solid crust and either the atmosphere or the water column.’</div>
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<div>Or should we have two separate terms to differentiate between seabed/water body and soil/atmosphere boundaries? My current thinking would be ‘no’ because that would be the start of the slippery slope of using a vertical coverage term (L131 is defined
as ‘Terms used to describe data coverage over the vertical (z) co-ordinate.’) to characterise the nature of the boundary. However, other opinions on this or any other aspect of the proposed vocabulary change are welcome.</div>
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<div>Please let me have any thoughts in the next week or so as a vocabulary user awaits something suitable.</div>
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<div>Cheers, Roy.</div>
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