Obviously, the samples should have been divided into sets, labelled, and distributed to the investigating parties from the wellsite, or the nearest shipping point. Sheesh! We do this on oil wells all the time.
Point two: A thriving plankton population does not rule out a massive die-off in terrestrial metazoans, but could result from the increase in nutrients released by the impact. While this might be good for relatively basic aquatic organisms, the same impact could be catastrophic for vertebrate lifeforms and the plants which ultimately form the base of their food chain. It would not take a hundred years of darkness to cause mayhem, ecologically, only a few critical months of growing season.
If there were a major nuclear winter effect, some evidence of glaciation occuring somewhere at the K-T boundary should be present.
I find the 'study' results inconclusive for determining whether or not the impact killed the dinosaurs. They only deal with plankton.
You are right. A "mere" ten degree drop in temperature for a couple of years would devestate large terrestrial animals as a
result of a massive die off in the terrestrial food supply. In geologic terms the recovery of the ocean plankton would be almost instant in relationship to what we find in the micro fossils. The dinosaurs could have been killed off and the oceans could have been "almost" wiped out but recovered quickly in relationship to the micro fossil record. The real way to intepret the data is the entire fossil record and die off at the K2 boundry. Many other species also "bit the dust" at the same time. This lends support to the impact theory but does not verify it.