Varied diatoms seen through a microscope
A shiny turquoise spot in the middle of the antarctic ocean-blue waters, which has intrigued scientists since it was first spotted in satellite images in the early 2000s, was finally deciphered by oceanographers.
The mapping of phytoplankton concentrations and biogeochemical compounds revealed a curious combination of microorganisms – that challenges the assumptions about how the gelid waters of the most austral oceans in the world absorb carbon.
In the midst of the antarctic ocean-blue waters, north of a turquoise spot, first spotted in satellite images in the early 2000s, flows a reflective ring of seawater-“large calcitis belt“.
Also discovered about two decades ago, it was discovered at the time this ring contains thousands of millions of ‘Cocolitóforos‘ alien aspect that feed on sunlight – so called for their reflective scales, known as coconuts, tells the.
Using inorganic carbon to make their calcitis scales, the belt cocolythephous Essential role in the global carbon cycleconcentrating about 30 million tons of the element per year.
High concentrations of cocolytes increase ocean reflectance (The relationship between the radiation flow that focuses on its surface and the reflected radiation flow), which satellite oceanographers usually use to estimate ocean calcitis concentrations.
The mysterious spot of sparkling blue-blue could also be explained by the cocolytes, were it not for the fact that the waters were too cold for microorganisms to thrive.
Often hidden by agitated seas, dense clouds and iceberments, turquoise tides have been so far difficult to observe the space.
In a new one, recently published in the global Biogeochemical Cycles, the oceanographer Barney Balch And his colleagues decided that the only way to find out what was really going on was to venture into the sea.
As the authors write in their article, “there have been few maritime verification measurements in the region due to their isolation.”
On board the investigation ship Roger Revelle, Balch and his team traveled from Hawaii towards the South Polo, Passing through the large belt belt – that, being summer in the southern hemisphere, was in full flowering.
“Satellites only see the first meters of the oceanBut we managed to deepen with multiple measurements to various depths, ”Balch explains.“ There is nothing like measuring something in many ways to tell a more complete story. ”
These measurements included ocean color, calcification ratephotosynthesis rate and, most importantly, inorganic and silica carbon concentrations; Minerals that represent cocolythephous and their rivals, diatoms, which make their own microscopic silica glass shells.
Both these plankton – Diatoms and cocolyritophores – fill niches so similar that they eventually compete with each other, kidnapping organic carbon in the deep ocean and producing energy that feeds food chains Massive sea that extend around the world.
The large calcitis belt has always been considered Cocolitophores Territory; anywhere south of your polar front is the kingdom of diatoms.
“High reflectance waters south of the large calcitis belt have been regularly observed, but questioned, due to the fact that cocolitophores normally Not being found in such cold waters“Write the authors of the study.
“Instead, it was suggested that the high reflectance could be due to other high reflectance materials as Loose ice, glacial flour, flowering algae, increased bubble incidence, or other suspended particulate materialas high concentrations of suspended opal associated with diatoms, ”says the investigators.
The water samples brought not just the first calcification test happening in these Águas do Sul, but Direct visual evidence of cocolythephous Living – where no one expected them to.
“Moderate concentrations of coated cocolyphoros and highlights were observed south of the large calcitis belt up to 60 ° S,” the authors report. But some scattered coconuts cannot reflect enough light to explain the shine in satellite images.
Diatoms, apparently, are so dense in these waters that their vitreous and reflective structures managed to produce a similar optical effect to cocolythephous.
“Our results suggest that these highly reflective polar waters result from dispersion by diatomous, non -cocolyritoral frustulesand were poorly identified as particulate inorganic carbon In satellite measurements, ”concluded the study authors.
Solved mystery.
