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The three surprising micro-engines at the heart of our ecosystems

By Dr Jim Ormond and Jane Fiona Cumming

'Enjoy the little things in life because one day you`ll look back and realize they were the big things'

Kurt Vonnegut

All life, no matter how big or small, depends on another plant or animal species for its survival. At the heart of these dependencies are a small number of building blocks upon which all life is reliant. Yet our Anthropogenic approach to to the world is increasingly clogging up and reversing the life giving properties of these "micro-engines of life".

1. "The dance of the plankton"

At the bottom of the ocean’s food chain are phytoplankton. They are the foremost link in the food chain, supporting simple marine life, right up to the blue whale. Typically, zooplankton eat phytoplankton, fish eat zooplankton, and so on. Central to the success of this food chain, is phytoplankton's ability to photosynthesize the sun’s rays to produce energy. Through photosynthesis, phytoplankton absorb carbon dioxide to produce nearly 50% of the global oxygen, thereby playing a fundamental in our battle against climate change.

“Half of the oxygen we breathe comes from forests, the other half from these tiny marine plants”

Phytoplankton are however under threat. Unlike plant ecosystems, the amount of phytoplankton in the ocean is closely linked to the abundance of organisms that eat phytoplankton, creating a 'perpetual dance' between predators and prey. Even a tiny imbalance in this predator-prey relationship, caused by environmental variability, gives rise to massive phytoplankton blooms. This can result in huge impacts on ocean productivity, fisheries and carbon cycling. For instance, a disturbance may involve deep mixing of the surface ocean by storms, bringing up deep ocean water along coasts (known as coastal upwelling).

In other parts of the ocean, populations of these microscopic organisms are plummeting, with an average decline of 1% per year over the last century. This decline is related to increasing sea surface temperatures and ocean acidification (the pH of the oceans has shifted to 8.1 from 8.2 and could drop to 7.8 by the year 2100).

Ocean acidification is a massive threat to plankton, and therefore marine animals and ultimately the Earth itself

2. "The factory of life on earth"

Soil biology is the engine of the Earth. One gram of soil can contain up to one million species. This ranges from micro-organisms (e.g. bacteria, fungi, protozoa and nematodes); meso-fauna (e.g. acari and springtails) to more familiar macro-fauna (e.g. earthworms and termites). This biological component of soil is fundamental for all life of Earth. Apart from growing our food, filtering our water and holding back floods, they regulate the climate and sustain wildlife.

Without the biological component of soils, no crops or trees would grow.

Yet, just as with phytoplankton, soil biodiversity is in grave danger. Climate change, land sealing, water and air erosion and the removal of carbon from soil are all combining to threaten this fauna.

Whilst, soil biodiversity is resilient; it is estimated that 90% of species may be lost without critical destroying soil, a knock-on effect still occurs. In the short-term, loss of soil fertility increases the risk of crop-failure and food insecurity. In the longer-term, a decline in soil biodiversity impacts the food chain, including insects, birds, mammals, the outcomes of which may take decades.

3. "The humble leaf"

The final micro-engine is the leaf. Whilst the most visible of our three micro-engines, it is worth reminding ourselves of the number of functions of the humble leaf.

Food - the carbohydrate that is produced by a leaf in the process of photosynthesis sustains animal life, both directly and indirectly. Oxygen that a plant's leaf gives off is essential to the continuing existence of animals and other aerobic organisms. Transpiration by a leaf also plays an important role in the continuous ascent of water and nutrients from the soil and roots to biosphere.

Climate change - through converting carbon dioxide into carbon and storing it in their plant matter - plants are critical agents in mitigating increasing carbon emissions. Indeed scientists developing the next generation of clean power sources have explored how to copy, and ultimately improve upon this capability.

Plants are our lifeline – but we’re letting them die

However, as with the other two micro-engines, human activity is impacting the leaf's ability to support our Planet. Industrialization, urbanization, economic growth and associated increase in energy demands have all resulted in a profound deterioration of air quality. The exposure of these pollutants to a leaf can cause a reduction in the concentration of their photosynthetic pigments, which affects the plant productivity, germination of seeds, length of pedicles, and number of flowers in florescence.

It is high time we value the small things

To conclude, what is clear is a small number of micro-engines generate the food, convert the energy, and clean the water upon which we rely. The protection of these micro-engines are critical if we are to achieve the UN goal of protecting the Earth’s life-support system. Yet by not being able to see these micro-engines - we sadly do not value their importance... As Kurt Vonnegut once said.

When the last living thing has died on account of us, how poetical it would be if Earth could say, in a voice floating up perhaps from the floor of the Grand Canyon, ''It is done." People did not like it here
Kurt Vonnegut

Photo credit: Emily Morter

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