Phytoplankton is a marine plant with thorns and serrated edges to increase water pressure so it does not sink. Naturally it can only survive by floating. Cells of these plants are provided with chloroplast that converts sunlight to create glucose and amino acids: organic matter that is the basis of life. Material nature gives these plants, no larger than half a millimeter a blueprint for their survival.
Phytoplankton forms the basis of the food chain: so prodigiously it proliferates. Phytoplankton feeds by photosynthesis. Thereby what it creates is organic matter that sustains conditions for life on the earth.
Phosphorus is a vital component for the survival of phytoplankton. Phosphorus from the bottom of the sea is brought to surface by upwelling caused by earth’s rotation. There are phosphorus and oxygen cycles (see note.) that play off one another and keep oxygen concentration in earth’s atmosphere stable.
Too much of oxygen in the seawater would have proved bad for phytoplankton since it impedes photosynthesis. So phosphorous content in the water would help it to survive. It helps by reducing oxygen level in the seawater. Phosphorous is also essential in energy production and building up of DNA and RNA in genes. How a certain characteristic like earth’s rotation helps a marine plant to survive is not simple; nor is it straightforward. By the same token history is made like the working of two cycles in tandem from selfsame circumstances to achieve some sort of balance.
How Rome sinks to the bottom from being a superpower will mark the rise of Visigoths, vandals and such like. These hordes of marauders from far corners of the globe found Rome ready to totter and they did . Causes are spliced from circumstances and Oneness of Things lets beggars or vandals their chance to change history as Rome had theirs.
Empires rise and fall but Truth remains constant and impartial absolutely.
Note: Oxygen cycle: oxygen cycle is the biogeochemical cycle that describes the movement of oxygen within and between its three main reservoirs: the atmosphere, biosphere and the lithosphere. The process of photosynthesis dominates it.
Phosphorus cycle: as above but deals with the movement of phosphorus through the lithosphere, hydrosphere and biosphere. Weathering of rocks play a major role.