It’s a question I often get asked and it’s a fairly straightforward answer (with a twist).
The oceans and atmosphere are inextricably linked but the importance we bestow on the land is anthropocentric because we live there. It’s naturally important to us that we protect it. Nonetheless, if life in the ocean dies, we also suffer irreversible changes to land-based 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 and climate.
The ocean is the planet’s main heat-regulator and as our Sun has aged, Earth has become exposed to more heat so it’s even more important that our ocean’s systems function(Of an ecosystem). A subset of ecosystem processes and structures, where the ecosystem does something that provides an ecosystem service of value to people. More effectively. It’s not the mere presence of the ocean that cools Earth, it’s the ecosystems and lifeforms that live in it.
If we wipe out lifeforms on Earth today, the universe couldn’t recreate habitable conditions because things have become too warm already.
1. The boundary between warmer sunlit upper layers and cooler lower layers is called the thermoclineThermoclines are boundaries between gradients of temperature and salinity. The Mixing Layer Depth is usually defined as the depth where it is 0.5°C cooler than the surface temperature, that accounts for changes in salinity [1]. When the mixed layer is shallower, is has more prey abundance, because the boundary layer nutrients are easier to reach. Mixing layer depth varies from More. 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 settle over time into deeper waters and it takes energy to resuspend them at the surface.
2. Nutrient-filled freshwater flows into the ocean via rivers.
3. Significant phosphorous & nitrogen input by seabirds creates conditions for stabilisation and colonisation of islands, as well as nutrients flowing onto surrounding reefs.
4. Suspension of nutrient-rich water at the surface combines with sunlight to create conditions ideal for algal and planktonA soup of micro-organisms. Usually refers to all the zooplankton and algae in the ocean but can also be used to describe tiny insects in the atmosphere (see aerial plankton). More growth.
5. Marine mammals, predatory fish, dolphins and seabirds forage communally. The result is the amplificationAmplification (of nutrients and energy). Animals consume plants and other animals and in doing so, reintroduce important energy-containing nutrients back into the environment, at even higher concentrations and in patches. Amplification of energy is driven by migration and happens at every scale, from insects moving daily in and out of your vegetable patch, to African wildebeest herds and the seasonal More and release of nutrients back into the system, creating more plankton growth.
6. Pilot whales, tuna and sharks feed along the thermocline, creating mixing, 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 amplification and suspension of material into the ocean’s upper layer.
7. Along the edges of reefs and seamounts, tidal action creates currents that resuspends material from the depths.
8. Waves and coastal rainfall drive material off reefs into deeper water. A continual shower of nutrient-rich material descends as “marine snow” to settle on the seafloor.
9. Seasonal winds drive upwelling and the proximity of atoll flushing and reef processes creates particularly rich conditions along the margin of reefs and islands.
10. Due to their large size and numbers, whales are drivers of nutrient amplification (e.g. through defecation) and they also mix the thermocline layers by swimming through them.
11. Undersea features create upwelling, forcing energy- rich prey (squid, lanternfish etc) closer to the surface. Drawing by Simon Mustoe.
Cool water beneath the ocean surface mixes with the upper layers, extracting heat energy from the atmosphere (energy that’s continuously supplied by the Sun). More importantly, the carbon dioxide that would allow our planet to warm beyond liveable means, is trapped and stored by ocean biota. It’s our major carbon storage. The majority of dead animal life at the surface settles on the seabed and with three-quarters of the planet being ocean, there is a thick sediment layer. In parts of the Atlantic this is a kilometre deep and was deposited at rates of about a third of a centimetre every thousand years.
Before there were land plants or animals, about 400 million years ago, life thrived in the ocean. It wasn’t necessary for life to exist on land for Earth to enjoy a long period of relative stability (though conditions were not, as yet, suitable for humans or other animals).
Indeed, the rise of land plants created a new challenge for Earth. Their weathering and erosion of rocks, creation of soil and extraction of carbon from the atmosphere, created an influx of oxygen and iron, which quickly made the oceans anoxic and most sea life died in the Devonian mass extinctionAnimal life hasn't existed for very long on planet Earth. In the last 500 million years, there have been five mass extinctions, defined as events that wiped out at least 75% of animal life. The Devonian mass extinction is considered to have been caused by the rise of plants on land, which polluted the oceans in the absence of animals. More. It took the rise of land animals to moderate the excess waste created by plants so we could have the forests we see today but that also created the oxygenation of our atmosphere that we breathe. In that sense, the land is more important to humans.
The short answer is that the ocean and land are equally vital. We live on the land but the oceans regulate Earth’s temperature. We could investigate the relative importance of each of these components but that would be like arguing that the engine of a car is more important than its wheels. A car isn’t a car without both. Earth isn’t habitable, for humans at least, without a healthy functioning ocean and land environment.
Spotlight
“There is roughly 80 times more biomassThe weight of living organisms. Biomass can be measured in relation to the amount of carbon, the dry weight (with all moisture removed) or living weight. In general it can be used to describe the volume of energy that is contained inside systems, as the size of animals relates to their metabolism and therefore, how much energy they contain and More on land than in the oceans. Plants make up most of this difference but more than 70% of global animal biomass is found in the ocean. Earth has a plant-dominated landscape and an animal-dominated seascape”. But net primary production of carbon (see left) is similar. This also shows that fossil fuel is adding about equal amounts of C annually to the biosphere. Read more here.
