Saturday , January 16 2021

Much of the sea will change color by the end of the century



Global warming changes phytoplankton significantly in the world centers, which will affect the color of the sea by the end of the century, increasing its green and green regions.

Stitches need to detect these changes in tone, giving early warning of major changes to marine ecosystems, according to a new study by the Massachusetts Institute of Technology (MIT).

In an article published in Nature Communications, researchers report that they have developed a global model that emulates the growth and interaction of different phytoplankton or algae species, and how mixing of species in Several places change as the temperature increases. worldwide

The researchers also simulate how phytoplankton absorbs and reflects light, and how the color of the sea changes as global warming affects the composition of phytoplankton communities. The scientists implemented the model until the end of the 21st century and found that by the year 2100, more than 50 percent of worlds will change color due to climate change.

The work suggests that blue regions, such as subtitling, will become more bluer, reflecting even fewer phytoplankton, and life in general, in those waters, compared to & # 39 ; r existing ones. Some regions that are greener today, such as by the poles, can even become greenier, as warmer temperatures produce large flowers of more varied phytoplankton.

"The model suggests that the changes will not seem huge at first glance, and the ocean seems to have blue parts in the sub-tropical and green regions near the equator and, ruling, "said lead author Stephanie Dutkiewicz, research scientist at the MIT Department of Earth, Atmospheric and Design Sciences, and the Joint Program for Science and Global Change Policy. "That basic pattern will still be, but it will be different enough to affect the rest of the food web that supports phytoplankton," he added.

Chlorophyll

The color of the sea depends on how sunlight interacts with what is in the water. Water molecules only absorb almost all sunlight, excluding the laser part of the spectrum, which is reflected out. Therefore, relatively open countryside regions appear to be dark blue of space. If there are organisms in the sea, they can absorb and reflect different waves of light, depending on their individual properties.

Phytoplankton, for example, includes chlorophyll, a pigment which is mainly absorbed in the blue extracts of sunlight to produce carbon for photosynthesis, and less in green parts. As a result, more green light is reflected off the sea, giving the regions rich in algae richness.

Since the late 1990s satellite has taken continuous measurements of sea color. Scientists have used these measurements to obtain the amount of chlorophyll and, by extension, phytoplankton, in the sea region. But Dutkiewicz says that chlorophyll does not necessarily reflect the sensitive signal of climate change. Any significant change in chlorophyll may be due to global warming, but it could also be due to "natural variation": normal and periodic increase in chlorophyll due to natural climate-related phenomena.

"The El Niño or La Niña event will produce a very big change in chlorophyll because the number of nutrients that come to the system is changing," said Dutkiewicz. "Due to these wonderful natural changes that happen every few years, it's hard to see if things are changing due to climate change, if you're just looking at chlorophyll," he added.

Modeling ocean light

Instead of searching for estimates derived from scallops, the team thought that they could see a clear indication of the impact of climate change on phytoplankton by observing only the reflected satellite measurements of light. The team adapted a computer model that it has used in the past to predict changes in phytoplankton with increasing temperature and back acidity. This model collects information about phytoplankton, such as what they use and how they grow and incorporate this information into a physical model that can simulate currents. and mix oceans.

On this occasion, researchers added a new element to the model, which has not included in other marine modeling techniques: the ability to estimate specific light waves that can be absorbed and & # 39; reflected by the sea, depending on the size and type of organisms in a specific region.

"Sunlight will go into the sea, and what's in the ocean absorbs it, such as chlorophyll," said Dutkiewicz, "other things will absorb it or spread it, like something with hard creg, a complex process, how light is reflected in the sea to give it color ".

When the group of researchers compared the results of their model with the actual measurements of the reflected light that the satellites had in the past, it was found that both agreed that the model could be used to predict the color of the sea as it grows. environmental conditions will change in the future.

"The good thing about this model is that we can use it as a laboratory, where we can experiment, to see how our planet changes," said Dutkiewicz.

There is a signal in blues and green

As researchers increase the global temperatures in the model, up to 3 degrees Celsius by 2100, what most scientists predict will happen in a relatively unchanged situation of relatively few steps to reduce greenhouse gases , found Light bulbs responded to the green / green wave band faster.

In addition, Dutkiewicz noted that this band of green / green waves showed a very clear sign, or a change, owed specifically to climate change, which happened much earlier than previously scientists when observing chlorophyll , which is anticipated that they would show it. Climate change change in 2055.

"Chlorophyll is changing, but you can not see it because of its incredible natural variation," said Dutkiewicz, "but you can see a significant change in climate related in some of these wave bands, in the signal and sent to the satellites, so that's where we should be looking for satellite measurements, a real sign of change. "

According to its model, climate change is already changing the composition of phytoplankton and, by extension, the color of the oceans. At the end of the century, our blue planet can be changed visibly. "The 50% of the sea will have a marked difference in the color by the end of the 21st century – the Dutkiewicz statement – it could be very serious, different types of phytoplankton absorbs light differently and if climate change is change phytoplankton to another, which will also change the types of food websites they can carry out. "


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