Ocean Zones and Productivity

Biogeography II: Why Is The Sea Blue?

In this course, Dr Richard Field (University of Nottingham) explores the world of marine biogeography and tackles the question, why is the sea not green? We begin in the first module by breaking down the various zones of the ocean, both in terms of light intensity as well as productivity. In the second module, we dissect what we mean by productivity in the ocean, further discussing standing crop and why it differs so drastically between the ocean and land. In the third module, we look at some examples of aquatic vegetation but ultimately break down the limiting factors of why forests cannot grow in the open ocean. In the fourth and final module, we look at the transfer of energy through the ocean ecosystem. We discuss r-selected species, what they are and why the ocean favours these organisms and finish up by breaking down why in general the energy transfer in the ocean is more official than on land.

Ocean Zones and Productivity

In this first module, we look at the various zones of the ocean, both in terms which zones are the most bright and which are the most productive. We first: (i) look at the zones of the ocean based on how much light can access them, highlighting the photic zone as a crucial area where producers can survive and photosynthesise; we reference (ii) John Ryther as a pioneer in our understanding of the zones of productivity in the ocean; following this (iii) we focus on the upwelling as a key zone for productivity, as well as the Peruvian Anchovetta as an example of an upwelling zone; we then (iv) finish up by discussing John Rythers predictions on fishery limits.