Whale poop comes to the rescue

Today, everybody's into it. Local governments do it, too, forking out large sums of money in the process. The aim of the game is to save the planet; the method is recycling. Garbage is sorted at recycling plants around the world into separate piles of glass, aluminum, plastic and paper for further processing. Resources are finite; without recycling we may eventually run out of some of these products.

The same principle applies to earth's resources on a massive scale. Carbon, for instance, is a basic constituent of all living things, making up, for example, 18% of the human body by weight.¹ Yet carbon dioxide, the source of almost all carbon in living things, constitutes only about 0.038% of the atmosphere by volume. Stop and think; if the carbon that has been incorporated in all the trees, plants and animals over the millions of years of earth's history was locked up at death, the atmosphere would eventually be drained. Ditto for all the other elements that are used by living things.

To enable planet Earth to support life over eons, God set in motion a massive program of nutrient recycling. Furthermore, to ensure that nothing goes outrageously haywire, causing the extinction of life, He had to ensure that all the naturally-occurring chemicals of the atmosphere and ocean are maintained at a steady level; too much carbon dioxide in the atmosphere, for example, could prove fatal to the process of respiration. Not enough nitrogen in its various forms in the soil, rivers and oceans would mean starvation on a mass scale. And so on. The mechanisms set in motion for both recycling chemicals and maintaining them in a steady state are so highly sophisticated that nobody can possibly understand it all. Many scientists, for example, have devoted their lives to studying the complexities of the carbon cycle.² Not one has a perfect grasp of all the "wheels within wheels" involved in the process. Ditto for the nitrogen cycle and the phosphorus cycle; each one is like a huge machine with myriads of cogs.

Recycling is particularly complex in the oceans, where plankton "sucks in" nutrients from the water aroundit, then gets eaten by other animals - and so on ad infinitum. These animals produce tons of feces which begin to sink to the

depths; they die and begin to sink. Sure, the nutrients are gradually released back into the water as bacteria decompose them, but how do they get back to the surface where the plankton can reuse them? Myriads of pathways are taken, each path playing a distinct role in the entire cycle. Here and there, deep waters rise to the surface carrying the "decomposed nutrients" with them. Believe it or not, even whale poop plays a critical role in some parts of the world:

. marine mammals can enhance primary productivity in their feeding areas by concentrating nitrogen near the surface through the release of flocculent fecal plumes. Whales and seals may be responsible for replenishing 2.36104 metric tons of nitrogen per year in the Gulf of Maine's euphotic zone³, more than the input of all rivers combined . Thus. opposing the contribution of zooplankton, such as copepods, to the downward biological pump, cetaceans⁴ feeding deep in the water column effectively create an upward pump, enhancing nutrient availability for primary production in locations where whales gather to feed.⁵

Whales, you see, dive deep to catch their prey and then return to the surface, the place where the base of the food chain is found. Of course, in this case, they are not bringing back the products of bacterial decomposition of sinking feces or carcasses but the bodies (in their bellies) of deep-living squid, fish, and krill. The feces of whales are liquidy and therefore don't sink but float at the surface where they are subject to rapid decomposition and release of waste nutrients that can be used by plankton. Scientists call this system the "whale pump", which is responsible for a much quicker turnaround of nutrients than other cogs in the nutrient recycling machine. Studies of this system show that whales "play an important role in the delivery of recycled nitrogen to surface waters" and that the whale pump "provides a positive plankton nutrition feedback".

Ah, the wisdom of the Creator. And when you try to wrap your mind around the complexity of the pathways involved in nutrient cycles you cannot help but stand in awe of the sheer mind power required to work out all the details.

¹ Rodney Cotterill, The Cambridge Guide to the Material World, p. 320

² The pathways travelled by gaseous and inorganic carbon from the atmosphere and ocean into living things and back again. The mechanisms are so efficient that only about 1% of carbon incorporated into the bodies of marine creatures reaches the floor of the ocean and gets locked up in bottom sediments.

³ The sunlit upper waters of the ocean where photosynthesis takes place

⁴ Whales and dolphins

⁵ Roman & McCarthy, The Whale Pump: Marine Mammals Enhance Primary Productivity in a Coastal Basin, PLoS ONE, 5(10): e13255. doi:10.1371/journal.pone.0013255