Dating the 100,000 year Ice Age cycle depends on oxygen isotope changes in plankton shells taken from the sediment cores of the ocean bottoms. At https://phys.org/print434815829.html … we learn about a study published in the journal Nature Communications (January 4th 2018) that found that the age of plankton and the strength and direction of currents are key to how they are dispersed in the oceans – more so than water temperature, salinity, and nutrient availability. Is that an admission the use of foraminifera shells (usually broken and possibly digested) as a proxy of ocean temperature with a cycle of 100,000 years is a load of baloney?
This is all part of a trend as we had a paper a few years ago that showed plankton do not fall straight down on the ocean bottom but tend to drift with the tide. How might this affect the chalk – which is basically a heap of plankton shells that was once the bottom sediment of a shallow sea?