Article**: Oceans and Wetlands.
Photo: Migratory cormorants near the estuary of Sanyang Port in the Linhong River Estuary Wetland in Lianyungang, Jiangsu Province Source: Zhou Chong, a volunteer of the Green Society.
Estuaries, estuaries of rivers, are important biodiversity hotspots for marine life and natural coastal conservation, while playing a key role in food security and infrastructure. Blue carbon captured by coastal ecosystems, such as mangroves, acts as organic carbon "sinks" and also contributes to climate change mitigation.
However, as a link between rivers and the ocean, climate change has a huge impact on them.
The book Climate Change and Etuaries co-edited by Dr. Joey Crosswell of the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia, Dr. Michael Kennish of Rutgers University and Dr. Hans Paerl of the University of North Carolina highlights the importance of understanding estuaries and the growing pressures they are facing. The book brings together 75 authors from 10 countries and covers local and global perspectives on estuarine ecosystems.
Source: Taylor & Francis Group
The estuary is an ecological, cultural and economic powerhouse
Estuaries play an important role in our lives. About 40% of the world's population lives within 100 kilometers of the coast. In Australia, for example, 90% of the population lives within 50 kilometres of the coast. Experts estimate that estuarine and wetland services are worth trillions of dollars globally. This includes the ecological, economic and social benefits that estuaries bring to countries around the world.
Dr. Joey Crosswell emphasized that many of the services we value in our daily lives are related to the estuary. Estuaries are key to numerous industries, from recreational and commercial fisheries to aquaculture, tourism, power generation. Oil and gas operations, transportation, shipping, etc., also depend on them. "The world economy is largely dependent on estuaries and the abundant resources and services they provide. ”
In addition to their immediate economic value, it has also been the cradle of civilization. They have nurtured human settlements and cultures for thousands of years. Historically, estuaries have been natural harbors and gateways to cultural exchange, helping to shape the course of human history.
Climate change threatens the important role that estuaries play
Dr Joey Crosswell said the consequences of climate change on water and food security are among the most fundamental risks. First, access to clean water is threatened by saltwater intrusion due to rising sea levels and hydrological changes.
At the same time, surface waters are under siege by a range of environmental threats. Toxic algae blooms and rapidly increase in numbers, posing a threat to both wildlife and humans;Oxygen-deficient waters endanger marine life. Unprecedented marine heatwaves have upset the balance of aquatic ecosystems. As a result of absorbing excess carbon dioxide, these waters are continuing to acidify, altering marine habitats.
As fisheries and aquaculture depend on healthy coastal waters, these risks are also inextricably linked to food security. At the same time, infrastructure is also directly threatened by climate change. Severe storms, rising sea levels, flooding, and other extreme events can all affect coastal communities.
"The consequences include the loss of land and intertidal wetlands, with adverse impacts on biodiversity, ecosystem services and associated human livelihoods, especially economies dependent on fisheries and tourism," he said. ”
Estuaries face different risks compared to open coasts, and even between different types of estuarads. For example, estuarine lagoons and river deltas face different challenges. Similarly, estuaries in the tropics face different problems than estuaries at higher latitudes.
Some chapters in the book focus on specific drivers of change and specific habitats, while others examine the interaction of multiple stressors on the structure and function of estuarine systems," says Dr. Joey Crosswell.
Estuaries store "blue carbon" to mitigate climate change
In the science of the carbon cycle, blue carbon is a relatively young and rapidly developing concept.
It is often reduced to carbon stored in coastal and marine systems. This carbon is stored in the form of biomass and sediments from mangroves, tidal marshes, and seagrass meadows. Dr. Joey Crosswell said, "Most of the research in the last decade has focused on organic carbon stocks in mangroves, seagrasses, and salt marshes. ”
These vegetated coastal ecosystems can act as organic carbon sinks, thereby reducing the amount of carbon dioxide in the atmosphere. They do this primarily by storing it as soil carbon.
Therefore, management actions aimed at protecting and enhancing these blue carbon stocks are an important tool for mitigating climate change. However, there is a growing recognition that when it comes to blue carbon, we need to 'see the forest through the mangroves'. That is to say,The deeper value lies in the many cumulative benefits of coastal vegetation ecosystems, which are a guarantee of resilient and healthy coasts, including the provision of shoreline protection while maintaining fisheries and biodiversity.
Compilation: sara Review: Daisy
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