Last week Masters Student in Ecology Leisha Knack spoke about how whale wee works wonders for ecosystemsHow ecosystems function An ecosystem is a community of lifeforms that interact in such an optimal way that how ecosystems function best, is when all components (including humans and other animals) can persist and live alongside each other for the longest time possible. Ecosystems are fuelled by the energy created by plants (primary producers) that convert the Sun's heat energy More! Yes, that’s right. Urine is as important for ecosystems as it is for lemon trees. Which allows me to paraphrase the wonderful joke by Jim Moir (Vic Reeves). You don’t need a PhD to work that out, but you might need a pee-each-day … ha! Knack tells us that whales spill about 4,000 tonnes of nitrogen each year into the ocean from their pee alone. This is nutrientA substance that contains the raw materials for life. At a chemical level, these are contained inside compounds that are absorbed into the body and essential energy-containing molecules are extracted, so that energy can be transformed into other chemical processes that use the energy for living. More that their kind moves from one part of the ocean into relatively nutrient-poor tropical waters during their annual migration. This is having huge impacts on our coastlines.
The impact of distant animals on our nearby lives
“Before whaling, nutrientsEnergy and nutrients are the same thing. Plants capture energy from the Sun and store it in chemicals, via the process of photosynthesis. The excess greenery and waste that plants create, contain chemicals that animals can eat, in order to build their own bodies and reproduce. When a chemical is used this way, we call it a nutrient. As we More would have been three times higher than it is now’, Leisha Knack went on to say.
Indeed, the role of wildlife in creating life-supporting ecosystems has been wildly underrepresented in science … until now, thanks to scientists like Leisha. Rebounding populations of Humpback Whales around our coast are rebuilding natural processes that affect our farming and weather systems.
Blue Whales, the largest animal that ever lived on Earth, regulate climate by stirring and fertilising the ocean. They can even modulate the effect of Australia’s bushfires.
The capacity of animals to transport nutrients from biodiversity hotspots and spread them around the world was once ten to twenty times greater than it is today [1] but the recovery of whale populations is a sign of positive change that we are beginning to value. This might lead to one of the world’s largest whale sanctuaries ever created … a story I explore in more detail in ‘my latest in ‘How to Survive the Next 100 Years: Lessons from Nature‘.
Seabirds, the ultimate nutrient conveyors
Seabirds are another extraordinary nutrient transportation mechanism. Australia has two populous seabirds. 80,000 Wedge-tailed Shearwaters on the Great Barrier Reef’s Heron Island produce about 22 tonnes of guano each breeding season. Birds combine their waste into a material that allows them to carry less weight. The white part is an ammonia-rich concotion that also combines with waste from ocean surface algae to seed clouds on a continental scale. Guano is about 15% Nitrogen.
Before Europeans arrived, there were maybe 23 million Short-tailed Shearwaters breeding in southern Australia. These could have produced about 6,400 tonnes of guano per year–just at the breeding colonies–with presumably more being produced at sea, since the birds spend vastly longer periods there than they do on land. These are one of many species doing the same thing, with the collective total being many tens of thousands of tonnes of Nitrogen.
How much is 1,000 tonnes of Nitrogen? What does it mean?
What do all these figures mean though? You may ask. Well in 1995, the entire Nitrogen budget for the Great Barrier Reef coming from rivers was about 7,000 tonnes [2]. Total inputs including microbial communities and upwelling were thought to be in the order of 17,000 tonnes (N) and 1,400 tonnes (P), dwarfed twenty times by what they call recycling fluxes, which is the amount being processed through
the system by animals and plants. Put another way. The whole of the United Kingdom farming system runs on about 60,000 tonnes of Nitrogen fertiliser annually.
When you mentally calculate the number of animal and birds species living in the sea that are processing Nitrogen, recycling it and transporting it, it’s easy to see this is significant. It is, after all, how ecosystems have always run. The type of Nitrogen matters though. Natural systems produce nutrients that are ‘bio-available’ and generate ecosystem processes by amplifying the animal-led impacts. The kind we tip onto our farmland does the opposite when it’s used in excess.
Which is why rewilding our seas is the only way we can rebalance nature. Once again, animals are humanity’s best hope.
References
- Doughty, C., et al., Global nutrient transport in a world of giants. Proceedings of the National Academy of Sciences of the United States of America, 2015. 113.
- Nitrogen and Phosphorus Budgets for the Central Great Barrier Reef Shelf Miles Furnas, Alan W. Mitchell and Michele Skuza Tropical OceanographyThe study of the physical, chemical and biological properties of the ocean. More Program Australian Institute of Marine Science, Townsville A REPORT TO THE GREAT BARRIER REEF MARINE PARK AUTHORITY. © Great Barrier Reef Marine Park Authority 1995
