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Scientists from National Maritime Center (NOC) has published a study detailing how changes in plankton communities have resulted in changes in the color of more than half of the ocean.
New article 'Global climate change trends detected in marine ecological indicators’ Published in an online journal NaturePlankton communities in half of the world’s oceans have been affected by climate change over the past 20 years, a new study suggests.
The oceans are home to large blooms of plankton, tiny organisms carried by tides and currents that provide a rich source of nutrients for marine life. They are divided into phytoplankton – tiny plants – and zooplankton, tiny animals.
The scientists behind the study say their determination of a 20-year trend is significant, as prior to this study, the scientific consensus believed that 30 years of satellite data were needed to detect the trend of climate change at levels. Chlorophyll is distributed throughout the ocean.
Chlorophyll—the chemical that plants use to absorb energy from the sun during photosynthesis—gives plants their green color, and is therefore present in other forms of marine plants, such as phytoplankton and algae. The amount of vegetable matter present in the sea affects its color.
NOC scientists have determined that 20 years is enough time to detect changes in ocean color related to climate change.
Using NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS). Its Aqua research satelliteScientists analyzed measurements of ocean color to estimate the amount of chlorophyll in the ocean, a method that greatly reduced the time needed to collect the information.
By reducing observation time, this satellite research can be conducted during the lifetime of a satellite, as some long-term data collection does not last the full 30 years previously required. By focusing on long-duration satellite missions rather than the short-duration missions that make up the bulk of current research, the researchers said, this would allow future studies to create more detailed records of the data.
„The satellite data we analyzed reveals a change in color over a large area of the ocean that represents an area larger than all the land on Earth,” said Dr. BB Gale, principal scientist of the National Oceanic Center’s Marine Biogeosciences Group. Principal author of the article.
’The computer simulations we examined suggested that these color changes could be due to climate change. It is hoped that this paper will stimulate further work on the causes and consequences of these changes.’
The study found that a trend of plankton size change was detected in 56 percent of the ocean. Although the scientists say it is 'too soon to determine what this means for the ocean at large’, they believe climate change will drive ecosystems 'towards a dominance of smaller species of plankton’.
According to the researchers, the dominance of small plankton could be a potential cause of concern in the future, as it would make the ocean less capable of storing carbon. Data from the Intergovernmental Panel on Climate Change (IPCC) suggest that plankton could contribute between 5 percent and 17 percent of the ocean’s new carbon uptake by 2100.
Because small plankton have less ability to store carbon, this may reduce their effectiveness as a source of carbon sequestration.
’Global Climate Change Trends Detected in Marine Ecological Indicators’ by BB Cael and many othersAvailable to read at Online magazine Nature