Biology Reference
In-Depth Information
Change (m)
15
10
5
4
3
2
Shallower (deposition or fill)
East
Bay
1
Golden
Gate
No change
1
2
3
Deeper (erosion or removal)
4
5
10
15
0369 2 Kilometers
1850s to 1890s
Figure 3. Changes in sediment deposition and erosion patterns in the bay between
the 1850s and 1980s, largely as a result of hydraulic gold mining. (Bruce Jaffe)
settled out on a shoreline. “Rocks want to sink, because that's what rocks
do in water. They're 'negatively buoyant,' ” says Schoellhamer. “If the rock
had a life jacket on, it would be 'positively buoyant.' ” He goes on to explain
how two primary forcing mechanisms keep the rocks up in the water col-
umn instead of allowing them to sink down: tidal currents and wind-
waves.
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