A massive algal bloom covering nearly all remaining freshwater, and much of the coastal waters surrounding the split continent of Eurasia causes a much worse K/PG mass extinction, and is seen as a continuation of the event, as it was directly caused by the warming of the planet following the dust winter caused by the asteroid impact. This massive bloom starves most fish and marine life of oxygen in the waters surrounding the bloom, but massively increases atmospheric oxygen to 40% for a total of 1 million years. However in this time period many ferns and trees adapted to, and began to thrive in high oxygen environments, leading to massive forest growth in bands across the planet, generally within the tropics, however a few temperate rainforests began to sprout up in the later half of the blooms million, and the continuation of a high, yet slightly lower atmospheric oxygen level (AOL) of 35%
99% of all animal species were wiped out following the K/PG extinction, a major group of survivors were small holdouts of the Vespoidea, already evolved into the most primitive bees and ants. The few survivors of the extinction stayed small for the first million years, as food was scarce, and surviving past the larval stage was rarer. Due to this scarcity the queens began to lay more and more eggs to increase the chances of the eggs making it to adulthood. This expansion of Vespid populations is still fairly slow at this point in time. Certain species of solitary Vespids however, began laying less eggs and began to tend more to their eggs and beginning the adaptation of parental behavior.
Few species of Coleoptera, specifically the very first Stag Beetles, survived the extinction, and began to thrive in the high oxygen environment, while still small at this time, they are markedly larger than they were before. Small beetles in the family Dermestidae also survived the extinction, and thrived off of the thousands of corpses left behind, leading to a massive boom in their population, and rapid radiation into detritivore niches.
Many small flies also began radiating into the leftover detritivore niches, with little biological adaptation this early after the extinction event.