5 ms·
Lot of silt in that water! There has been some interesting debate recently on the efficacy of glacial erosion under the Greenland ice sheet -- and more broadly
by cbkeller 7y ago
Lot of silt in that water! There has been some interesting debate recently on the efficacy of glacial erosion under the Greenland ice sheet -- and more broadly whether or not global average erosion rate has increased due to northern hemisphere glaciation over the past few million years. One recent estimate [1] suggests:
> We find that, although runoff from Greenland represents only 1.1% of the Earth’s freshwater flux, the Greenland ice sheet produces approximately 8% of the modern fluvial export of suspended sediment to the global ocean.
[1] https://doi.org/10.1038/ngeo3046 https://doi.org/10.1038/ngeo3046
- adrianN 7y agoI wonder what effects on the ecosystem it will have when the ice sheet is too small to introduce comparable amounts of sediment into the ocean.
- cbkeller 7y agoThat's an interesting question. Fe and P are probably the most relevant nutrients that are abundant in suspended glacial rock flour. Since Fe3+ is pretty insoluble in seawater, the suspended (vs. dissolved) load might actually matter -- wind-blown dust would be the #1 competitor. The first relevant paper I found suggests the dust still dominates [1], but it was clearly enough of a consideration for them to write a paper about it. And sometimes the wind-blown dust is actually glacial rock flour [2], so the plot thickens! [1] https://doi.org/10.1007/s10533-015-0091-6 https://doi.org/10.1007/s10533-015-0091-6 [2] https://doi.org/10.1029/2010GL046573 https://doi.org/10.1029/2010GL046573