Nov 12, 2020 04:20 AM
Entangled: How a global seaweed ‘plague’ threatens West Africa’s coastline
https://news.mongabay.com/2020/11/entang...coastline/
SUMMARY POINTS: For nearly a decade, vast quantities of Sargassum seaweed have been washing ashore on either side of the Atlantic. The seaweed hampers the activities of coastal communities and damages ecosystems. Researchers are working to better understand the phenomenon, which may be linked to wind and ocean currents shifted by climate change, to nutrient-rich discharge from the Amazon and Congo rivers, or iron-laden dust from the Sahara. The seaweed comes from a new perennial bloom that may be a permanent feature of the Atlantic Ocean.
INTRO: From the Gulf of Guinea to the mouth of the Senegal River, a sprawling shroud of seaweed is choking coastal ecosystems and the fishing communities that depend on them. Offshore, it snags lines, breaks nets and clogs up outboard motors. On shore, it accumulates in vast brown heaps, tide after tide, obstructing both boatmen and nesting sea turtles. As the seaweed rots, it releases foul-smelling hydrogen sulfide gas, causing respiratory illness in local populations. And in nearshore habitats, the same processes of decay depletes the oxygen in the water, killing marine animals in gruesome mass die-offs.
“It came as a shock to people,” said Paul Lamin of Sierra Leone’s Environment Protection Agency, describing the first inundation of June 2011. “We had never experienced such a large quantity of seaweed washing on our beaches.” (MORE)
Future hurricanes may cause havoc inland
https://cosmosmagazine.com/earth/climate...oc-inland/
EXCERPTS: North Atlantic hurricanes are weakening more slowly than they used to when they hit land, according to a new study in the journal Nature, and it’s linked to climate change. Japanese researchers say those that develop over warmer oceans carry more moisture and therefore stay stronger for longer. There is thus a real risk than in the future they will reach communities further inland and be more destructive.
Previous studies have shown that climate change can intensify hurricanes over the open ocean, but this is the first, the researchers say, to establish a link between a warming climate and the smaller subset of hurricanes that have made landfall. “We know that coastal areas need to ready themselves for more intense hurricanes, but inland communities, who may not have the know-how or infrastructure to cope with such intense winds or heavy rainfall, also need to be prepared,” says Pinaki Chakraborty, from the Okinawa Institute of Science and Technology Graduate University.
[...] More stored moisture also makes hurricanes “wetter”, perhaps explaining why some recent hurricanes have unleashed high volumes of rainfall. “Current models of hurricane decay don’t consider moisture: they just view hurricanes that have made landfall as a dry vortex that rubs against the land and is slowed down by friction,” says Li. “Our work shows these models are incomplete, which is why this clear signature of climate change wasn’t previously captured.”
In a related commentary in Nature, Dan Chavas and Jie Chen from Purdue University, US, note that the extent of damage occurring inland depends on both the rate of storm decay and the speed of storm motion at landfall. “Hence, a slower decay could also lead to increases in damage farther inland, although changes in the speed of motion remain a point of contention,” they write. “Longer-lived storms might also increase the chances of interaction with the jet stream, which can sometimes produce hazardous weather that can extend much farther inland.” (MORE - details)
https://news.mongabay.com/2020/11/entang...coastline/
SUMMARY POINTS: For nearly a decade, vast quantities of Sargassum seaweed have been washing ashore on either side of the Atlantic. The seaweed hampers the activities of coastal communities and damages ecosystems. Researchers are working to better understand the phenomenon, which may be linked to wind and ocean currents shifted by climate change, to nutrient-rich discharge from the Amazon and Congo rivers, or iron-laden dust from the Sahara. The seaweed comes from a new perennial bloom that may be a permanent feature of the Atlantic Ocean.
INTRO: From the Gulf of Guinea to the mouth of the Senegal River, a sprawling shroud of seaweed is choking coastal ecosystems and the fishing communities that depend on them. Offshore, it snags lines, breaks nets and clogs up outboard motors. On shore, it accumulates in vast brown heaps, tide after tide, obstructing both boatmen and nesting sea turtles. As the seaweed rots, it releases foul-smelling hydrogen sulfide gas, causing respiratory illness in local populations. And in nearshore habitats, the same processes of decay depletes the oxygen in the water, killing marine animals in gruesome mass die-offs.
“It came as a shock to people,” said Paul Lamin of Sierra Leone’s Environment Protection Agency, describing the first inundation of June 2011. “We had never experienced such a large quantity of seaweed washing on our beaches.” (MORE)
Future hurricanes may cause havoc inland
https://cosmosmagazine.com/earth/climate...oc-inland/
EXCERPTS: North Atlantic hurricanes are weakening more slowly than they used to when they hit land, according to a new study in the journal Nature, and it’s linked to climate change. Japanese researchers say those that develop over warmer oceans carry more moisture and therefore stay stronger for longer. There is thus a real risk than in the future they will reach communities further inland and be more destructive.
Previous studies have shown that climate change can intensify hurricanes over the open ocean, but this is the first, the researchers say, to establish a link between a warming climate and the smaller subset of hurricanes that have made landfall. “We know that coastal areas need to ready themselves for more intense hurricanes, but inland communities, who may not have the know-how or infrastructure to cope with such intense winds or heavy rainfall, also need to be prepared,” says Pinaki Chakraborty, from the Okinawa Institute of Science and Technology Graduate University.
[...] More stored moisture also makes hurricanes “wetter”, perhaps explaining why some recent hurricanes have unleashed high volumes of rainfall. “Current models of hurricane decay don’t consider moisture: they just view hurricanes that have made landfall as a dry vortex that rubs against the land and is slowed down by friction,” says Li. “Our work shows these models are incomplete, which is why this clear signature of climate change wasn’t previously captured.”
In a related commentary in Nature, Dan Chavas and Jie Chen from Purdue University, US, note that the extent of damage occurring inland depends on both the rate of storm decay and the speed of storm motion at landfall. “Hence, a slower decay could also lead to increases in damage farther inland, although changes in the speed of motion remain a point of contention,” they write. “Longer-lived storms might also increase the chances of interaction with the jet stream, which can sometimes produce hazardous weather that can extend much farther inland.” (MORE - details)
