Data from satellites help track the world's largest kelp forest

Scientists at UC Santa Barbara University, USA, have developed a new way to study how environmental and climate factors affect giant kelp forest ecosystems on a large scale. ever before, including space and time.

The scientists combined the data collected underwater by divers at UC Santa Barbara University, USA with satellite images of giant kelp canopy made by Landsat 5 satellites . The results of this study are published in the journal Issue of Marine Ecology Progress Series , issued on May 16, 2011.

In the process of satellite mapping of marine ecosystems, a team of researchers from the University of UC Santa, USA, tracks the dynamics of the world's largest giant kelp forest stretching throughout the entire Santa Barbara Strait, about every 6 weeks, for a period of 25 years, from 1984 to 2009.

David Siegel (left), Daniel Reed and Kyle Cavanaugh

David Siegel, co-author, geography professor and co-director of the Earth Research Institute, UC Santa Barbara University, USA, notes that: Does Landsat 5 satellite have 25 years of recording images from the universe? ever seen before. " I have been involved in satellite development programs, and a satellite that has been on duty for more than 10 years is rare. A satellite continues its mission for more than 25 years as a miracle ", Siegel to speak. The original Landsat 5 satellite is planned to be used in only 3 years.

Giant kelp forests are located in temperate coastal areas around the world. They are among the most productive ecosystems on Earth, and giant kelp itself is a source of food and habitat for many marine species of many ecosystems and marine economic zones. near shore . Giant kelp also provides an important source of food for many terrestrial species and also creatures deep in the sea, when kelp is torn from the seabed, often washed up on the beach or swept out. offshore into deeper waters.

Giant kelp is particularly sensitive to changes in climate, changes in ocean waves and nutritional conditions. The scientists found that the dynamics affected the development of giant kelp in the contact area of ​​the Santa Barbara strait, largely controlled by the emergence of large waves. Meanwhile, kelp developed in the reserve is mostly controlled by low nutrient levels.

Images from Landsat 5 satellites provide the team with a new vision to observe the change of giant kelp forests over time. The Landsat 5 satellite was built at the Santa Barbara Research Center, in Santa Barbara County, and launched into space at Vandenberg Air Force Base, USA. It is designed to scan the entire world for 16 days and has collected millions of images. Until recently, these images were used in limited scientific studies because they were relatively expensive due to high costs.

However, in 2009, for the first time, all satellite image libraries were displayed for free to the public. " In the past, it was not feasible to photograph the series in a long time, because each of these images cost over $ 500 ," said Kyle C. Cavanaugh, the first author and graduate student in the faculty. study the sea, at UC Santa Barbara University, USA. " Previously, it was fortunate to have a few images. Once the data was released for free, we could suddenly receive hundreds of images over time ."

Giant kelp grows to more than 30.48 m in length and can grow up to 18 cm per day. Plants include bundles of combs that form a rope that extends from the bottom to the sea surface. Live combs range from 4 to 6 months, while individual plants live on average for two to three years. According to the article, " giant kelp constitutes a dense floating leaf arch at the surface of the sea, which is very impressive when viewed from above. Water absorbs almost all infrared energy transmitted through it, algae leaves The sheath is easily distinguished by using its near-infrared reflex signal. "

Cavanaugh explained that, thanks to satellite images, for the first time, Cavanaugh's team was able to see the biomass of giant kelp fluctuating in and between years in the region. " It changes a large number ," Cavanaugh said. " We know from scuba divers observations that individual kelp plants are growing fast and short-lived, but new data show that these transformative models are also present within and between years with rules. Much larger tissue, the entire forest may be wiped out in a few days, but then recovered in a few months . "

Seaweed (Photo: Kelpscape)

Long-term Santa Barbara Coastal Ecological Research Project (SBC LTER), based at UC Santa Barbara University and part of the Long-Term Ecological Research Network (LTER) of the National Science Foundation Ky has enhanced the collection of satellite image data. In 1980, the NSF established the LTER Program to support long-term research on ecological phenomena. SBC LTER became the 24th website on LTER in April 2000. Long-term Santa Barbara Coastal Ecological Research Projects contributed data for more than 10 years of research on giant kelp for research. Current rescue.

Scientists believe that interdisciplinary coordination between geographers and marine scientists is common at UC Santa Barbara University, USA and is a strength of marine scientific research program.

Daniel C. Reed, co-author and experimental biologist with the Maritime Science Institute of UC Santa Barbara, USA, is also the principal investigator of the SBC LTER project. Reed spent many hours as a research diver. He explained: " Kelp appears discrete patches. The patches are genetically and ecologically connected, the species that live on kelp can move from one patch to another. Other images Images from satellites allow us to look at the dynamics of the various patches that are developing and . how to expand, and to get a better feeling when We cannot get that feeling through the diver's sketches, however, the diver's sketches, help us correct the satellite data, so actually The importance to have both sources of information . "

The fourth author of this study is Philip E. Dennison. He received his doctorate in geography at UC Santa Barbara University, USA, and is currently an assistant professor at the Department of Geography, at the University of Utah, USA.

The team received funding from NASA and the US National Science Foundation.