Why did ocean productivity decline abruptly 4.6 million years ago?

#ClimateChange; #OceanProductivity

Fig. 1. Early Pliocene (4.5 Ma) paleogeographic reconstruction showing deep-sea drill sites (ODP and IODP) discussed in this study. In total, 25 paleoproductivity records from 18 (mostly low-latitude) sites were compiled (closed symbols). Other deep-sea sites (open symbols) and terrestrial records from Central China (squares) were evaluated but not included in the final data compilations. Modern (perennial and equatorial) upwelling regions are indicated as orange shadings. EAM: East Asian Monsoon (green shaded area). PF: Polar Front (Southern Ocean; dashed line). Map generated on www.odsn.de (webpage consulted in 2020). Credit: DOI: 10.1038/s41467–021–27784–6

By drilling deep down into sediments on the ocean floor researchers can travel back in time. A research team led by Uppsala University now presents new clues as to when and why a period often referred to as the ‘biogenic bloom’ came to an abrupt end. Changes in the shape of the Earth’s orbit around the Sun may have…