We terrans like to think we know all about life on earth.
After all we’ve explored it ‘all’ for centuries.
In the blue part of this Blue Planet giant zooplankton have just been found to be in such abundance that their biomass dwarfs the animal life of the entire African continent.
Very recently a team of ocean plankton scientists revealed surprising numbers describing “large” planktonic (large being up to 1 cm in diameter) organisms in the super taxon group Rhizaria (artist’s impression above). It seems this globally widespread group of animals have previously been completely underestimated. These organisms are a large part of life on earth and conservatively make up 33% of the total abundance of large zooplankton in the world’s oceans, and account for 5% of the overall marine biomass.
To put that 5% marine biomass in context it is far more than the mass of all the combined animal life found on the African continent! Imagine that, we have missed all the herds elephants, zebras, wildebeests, antelopes, apes, flamingos, hippos, crocodiles and people of Africa. It’s as if no one had ever looked to see the wonder of life in Africa, or rather in the blue part of this blue planet.
The study was carried out assisted by samples collected during eleven oceanographic campaigns (2008-2013) covering the world’s main oceanic regions. The paper, Giant Protists of the Oceans, published on 20 April 2016 on the website of the journal Nature.
Although many of the ocean plankton are barely visible or even invisible to the naked eye this is their blue planet not ours. Their role in nature includes a vast variety of tiny organisms that produce most the Earth’s oxygen, actively control the climate, and form the base of the oceanic food chain that feeds fish and all of ocean life. The Rhizarians, from their Latin name Rhizaria, are a group of large planktonic organisms whose importance has been known but largely ignored.
Fragile Beautiful Plankton Sans Gravity
One key problem with understanding plankton is that they are almost all so incredibly delicate that the act of attempting to collect them for study destroys most of all samples. They have evolved for a life on earth in blue space where the effects of gravity are all but gone and growing in the distant ocean far from shore with nothing to bump into they have no need for hard bodies. However carefully we trawl our plankton nets we are certain to damage the most fragile organisms such as rhizarians and salps preventing their identification and measurement. In every plankton net there is always a large amount of unidentifiable goo.
The marine biologists and oceanographers of this recent paper joined forces to study samples collected during eleven oceanographic campaigns from 2008 to 2013, using a less destructive method, namely an underwater camera deployed at depth. This in situ imaging system, which involved no touching of the delicate life, was used to study the organisms directly in their environment without damaging them.
Many forms of ocean life are so delicate that they simply dissolve into nothingness at the slightest touch.
The images studied came from 1500 camera deployments at nearly 900 stations around our entire blue planet. In total, the scientists analyzed 1.8 million images in order to quantify the abundance and biomass represented by Rhizaria.
The results were stunning: The measurements show unequivocally that Rhizaria make up more than a quarter of the total abundance of the world’s large zooplankton. They account for 5% of the total biomass in the oceans (taking into account all organisms, from tiny plankton to giant whales). The presence of Rhizaria in all the planet’s oceans had previously not been completely overlooked but in much of the world almost no data exists save anecdotal reports.
These giants of the world of plankton it is reported are not evenly distributed and surprisingly the report suggests they are predominant in the nutrient-poor regions (located at the center of the large oceans) that cover most of the ocean area. This distribution might be explained by Rhizaria’s ability to live in association (symbiosis) with microalgae, just like coral. In symbiosis, the partnership between organisms is based on mutual exchange of food/nutrients.
Rhizaria graze in vast ephemeral ocean pastures and in doing so while benefitting from the nutrients of the photosynthetic phyto-plankton in turn they tend and fertilize their ocean pasture recycling vital nutrients just like the worms and microbes in your garden compost. By performing this vital ecosystem service Rhizaria are able to not only survive but indeed thrive in the nutrient-deficient waters they care for. Plankton are slowly sharing their secrets, unveiling unsuspected wealth and biodiversity.
If you haven’t noticed this blog is all about the plight of ocean plankton pastures a most important part of life on earth which are in terrible peril and how we must become, like Rhizaria, caring stewards of our ocean pastures. Take a few minutes and read some of the material here. The oceans are in trouble and the urgent call is for “all hands on deck,” join us.
Read about the fantastic life of Ernst Haeckel or watch the video below, you will be thrilled to see some of the wonders of plankton.