Coral reefs are also known as the ‘tropical
rainforests of the ocean’ because of their incredible diversity of life. Corals
are one of the most productive ecosystems on Earth, providing essential services
to mankind such as fisheries, coastal protection, medicines, recreation, and
tourism, thanks to their structural complexity. Corals are microscopic
invertebrates that live in colonies and rely on a symbiotic interaction with
zooxanthellae algae for nutrition and energy. Coral reefs form over thousands of
years as the limestone skeletons built by corals build and serve as a structural
foundation for living corals. Reefs are thought to be home to millions of
species, ranging from vividly colored tropical fish to sea cucumbers that
generate anti-cancer chemicals, according to scientists.
Coral reefs, like tropical rainforests, are threatened by human activities. Their ecosystems are particularly vulnerable, due to their sensitivity to ocean temperature. When corals are physiologically stressed, such as when water temperatures rise, they may lose a significant amount of their symbiotic algae, a process known as "bleaching." Short-term bleaching can be reversed, but long-term bleaching can cause lasting damage. Coral reefs throughout the world experienced the worst bleaching on record in 1998, when tropical sea surface temperatures were at their highest in recorded history. Even worse, approximately 60% of the 135,000-square-mile Great Barrier Reef was bleached in 2002. Many of these coral reef ecosystems are expected to take decades to restore, even in the best of circumstances.
Pollution, industrial activity, overfishing, siltation, cyanide and dynamite
fishing, and anchors all pose risks to the rainforest of the ocean, but scientists are most
concerned about global climate change. Scientists have developed the world's largest digitized map
of kelp forests, which could be a useful tool for monitoring the health of these underwater
rainforests that store vast amounts of carbon dioxide but are threatened by warming oceans.
KelpWatch.org, the world's largest digital map of kelp forests in terms of time and geography, was just launched by a group of American scientists. The open-source web application examines over 40 years of Landsat satellite data and dynamically depicts the kelp forest canopy from Baja California, Mexico, to the Oregon-Washington State boundary. Kelp forests provide habitat for over 800 marine species, including sea otters, whales, and commercially valuable shellfish like abalone, in addition to acting as a barrier against climate change. Kelp protects beaches from storms and grooms waves for a multimillion-dollar surfing business in locations like California. It can also be converted into biofuel and is used in food and cosmetics. Between 2014 and 2017, a climate-driven marine heatwave wiped out 95 percent of kelp forests along a 200-mile length of California's north coast, wreaking havoc on local fishing communities.
Dr. Kristen Elsmore, an environmental scientist at CDFW, remarked, "Kelpwatch.org provides a unique platform to visualize kelp canopy extent and obtain the corresponding data all in one spot. The interactive elements are especially useful for evaluating kelp within a certain management area and exploring prospective areas for kelp restoration pilot projects. Kelpwatch.org can provide a central platform for data openness and communication for both the general public and resource managers." Many kelp forest ecosystems, which provide ‘crucial functions’ for both humans and the environment, have seen historic and continuous reductions. Kelp loss has been accelerated in many parts of the world as a result of changing ocean conditions, particularly marine heatwaves linked to climate change, with more losses expected as ocean temperatures rise.
Before the launch of Kelpwatch.org, academics and state agencies tasked with management had a significant barrier in obtaining historical data on trends and changes in kelp forest abundance across wide areas. The web tool and its data have already been used to inform the California Department of Fish and Wildlife's (CDFW) Enhanced Status Report for giant and bull kelp, as well as the early stages of the Kelp Restoration and Management Plan development. Leading specialists have used the technology to stimulate scientific inquiry into the health of kelp forests in a changing ocean. Dr. Mark Carr, a professor of marine ecology at the University of California, Santa Cruz, said, "We've found Kelpwatch.org to be invaluable for documenting regional patterns of kelp dynamics, especially for assessing the consequences and patterns of recovery from sea urchin outbreaks that followed the 2013 seastar wasting disease and the 2014–2016 marine heatwave. It's been a useful study tool as well as a means of communicating kelp loss patterns to others."
The researchers were the first to use Landsat satellite photography to map the density of kelp forests. They began collaborating with The Nature Conservancy in California in 2019 to develop an online visualization tool to better Kelp forest mapping and monitoring. They then spent years accumulating that information so that it could be used to visualize changes in kelp forest size over time. According to Kyle Cavanaugh, a marine scientist and associate professor of geography at UCLA, kelp forest canopies have visual features with terrestrial forest canopies, making them recognizable from space.
The Kelpwatch.org team discovered an ‘unprecedented and worsening’ collapse of kelp forests around the Monterey Peninsula, an iconic kelp-dominated stretch of California's coast, using the tool to conduct flagship analyses on kelp dynamics along the west coast of the United States in response to the 2014–2016 record-breaking marine heatwave. The decline near Monterey and elsewhere has been described as ‘alarming,’ and attempts are underway to restore kelp forests in hard-hit areas such as the North Coast. The researchers cited the ‘rapid recovery’ of kelp canopy cover in Bahia Tortugas, Baja California Sur, which has shown complete and persistent recovery after the 2018 marine heatwave.