| Ամփոփում: | The rise of animals across the Ediacaran–Cambrian transition marked a step-change in the
history of life, from a microbially-dominated world to the complex macroscopic biosphere
we see today. While the importance of bioturbation and swimming in altering the structure
and function of Earth systems is well established, the influence of epifaunal animals on the
hydrodynamics of marine environments is not well understood. Of particular interest are the
oldest ‘marine animal forests’, which comprise a diversity of sessile soft-bodied organisms
dominated by the fractally-branching rangeomorphs. Typified by fossil assemblages from
the Ediacaran of Mistaken Point, Newfoundland, these ancient communities might have
played a pivotal role in structuring marine environments, similar to modern ecosystems,
but our understanding of how they impacted fluid flow in the water column is limited. Here,
we use ecological modelling and computational flow simulations to explore how Ediacaran
marine animal forests influenced their surrounding environment. Our results reveal how
organism morphology and community structure and composition combined to impact vertical
mixing of the surrounding water. We find that Mistaken Point communities were capable of
generating high-mixing conditions, thereby likely promoting gas and nutrient transport within
the ‘canopy’. This mixing could have served to enhance local-scale oxygen concentrations
and redistribute resources like dissolved organic carbon. Our work suggests that Ediacaran
marine animal forests may have contributed to the ventilation of the oceans over 560 million
years ago, well before the Cambrian explosion of animals.
|
|---|