Monthly Archives: April 2011
ScienceDaily (Apr. 19, 2011) — Earth has 657 more barrier islands than previously thought, according to a new global survey by researchers from Duke University and Meredith College.
The researchers identified a total of 2,149 barrier islands worldwide using satellite images, topographical maps and navigational charts. The new total is significantly higher than the 1,492 islands identified in a 2001 survey conducted without the aid of publicly available satellite imagery.
All told, the 2,149 barrier islands measure 20,783 kilometers in length, are found along all continents except Antarctica and in all oceans, and make up roughly 10 percent of Earth’s continental shorelines. Seventy-four percent of the islands are found in the northern hemisphere.
Barrier islands help protect low-lying mainland coasts against erosion and storm damage, and can be important wildlife habitats. The nation with the most barrier islands is the United States, with 405, including those along the Alaskan Arctic shoreline.
The survey results appear in the current issue of the peer-reviewed Journal of Coastal Research.
“This provides proof that barrier islands exist in every climate and in every tide-wave combination,” says Orrin H. Pilkey, James B. Duke Professor Emeritus of Geology at Duke’s Nicholas School of the Environment. “We found that everywhere there is a flat piece of land next to the coast, a reasonable supply of sand, enough waves to move sand or sediment about, and a recent sea-level rise that caused a crooked shoreline, barrier islands exist.”
Barrier islands often form as chains of long, low, narrow offshore deposits of sand and sediment, running parallel to a coast but separated from it by bays, estuaries or lagoons. Unlike stationary landforms, barrier islands build up, erode, migrate and rebuild over time in response to waves, tides, currents and other physical processes in the open ocean environment.
The 657 newly identified barrier islands didn’t miraculously appear in the last decade, explains Matthew L. Stutz, assistant professor of geosciences at Meredith, located in Raleigh, N.C. They’ve long existed but were overlooked or misclassified in past surveys.
Previously, for instance, scientists believed barrier islands couldn’t exist in locations with seasonal tides of more than four meters. Yet Stutz and Pilkey’s survey identifies the world’s longest chain of barrier islands along a stretch of the equatorial coast of Brazil, where spring tides reach seven meters.
The 54-island chain extends 571 kilometers along the fringe of a mangrove forest south of the mouth of the Amazon River. Past surveys didn’t recognize it as a barrier island coast partly because older, low-resolution satellite images didn’t show a clear separation between the islands and mangrove, Stutz says, but also because the chain didn’t match the wave-tide criteria used to classify barrier islands in the United States, where most studies have been conducted. Scientists failed to consider that supplies of replenishing sand are so plentiful along the equatorial Brazilian coast that they can compensate for the erosion caused by higher spring tides.
Stutz and Pilkey say the survey’s findings — which formed part of Stutz’s dissertation when he was a doctoral student at Duke — illustrate the need for a new way to classify and study barrier islands, one that takes into account the complex interplay of local, regional and global variables that shape where the islands form and how they evolve.
“Are there clues there to predict which of today’s islands might be in danger of disappearing in the near future?” Stutz asks.
The potential for significant climate and sea level change this century “underscores the need to improve our understanding of the fundamental roles these factors have played historically in island evolution, in order to help us better predict future impacts,” Pilkey says.
“Barrier islands, especially in the temperate zone, are under tremendous development pressure, a rush to the oceanfront that ironically is timed to a period of rising sea levels and shoreline retreat,” he says.
A developed barrier island, held in place by seawalls, jetties or groins, can’t migrate. “It essentially becomes a sitting duck unable to respond to the changes occurring around it.”
ScienceDaily (Apr. 17, 2011) — The coastline in Arctic regions reacts to climate change with increased erosion and retreats by half a metre per year on average. This means substantial changes for Arctic ecosystems near the coast and the population living there.
A consortium of more than thirty scientists from ten countries, including researchers from the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association and from the Helmholtz Centre in Geesthacht, comes to this conclusion in two studies published in Estuaries and Coasts. They jointly investigated over 100,000 kilometres and thus a fourth of all Arctic coasts and their results have now been published for the first time.
The changes are particularly dramatic in the Laptev, East Siberian and Beaufort Seas, where coastal erosion rates reach more than 8 metres a year in some cases. Since around a third of the world’s coasts are located in the Arctic permafrost, coastal erosion may affect enormous areas in future. In general Arctic coasts react more sensitively to global warming than coasts in the mid-latitudes. Up to now they have been protected against the eroding force of the waves by large sea ice areas. Due to the continuous decline in sea ice, this protection is jeopardised and we have to reckon with rapid changes in a situation that has remained stable for millennia.
Two thirds of the Arctic coasts do not consist of rock, but of frozen soft substrate (permafrost). And precisely these coasts are extremely hard hit by erosion. As a rule, Arctic regions are quite thinly populated. However, as nearly everywhere in the world, the coasts in the far north are important axes for economic and social life. The growing need for global energy resources as well as increasing tourism and freight transport additionally intensify anthropogenic influence on the coastal regions of the Arctic. For wild animal stocks, like the great caribou herds of the north, and the widespread freshwater lakes near the coast progressive erosion brings about significant changes in ecological conditions.
More than thirty scientists from ten countries were involved in preparing the 170-page status report entitled “State of the Arctic Coast 2010.” The study was initiated and coordinated by the International Arctic Science Committee (IASC), the international joint project Land-Ocean Interactions in the Coastal Zone (LOICZ), the International Permafrost Association (IPA) and the Arctic Monitoring and Assessment Programme (AMAP) working group of the Arctic Council.
“When systematic data acquisition began in 2000, detailed information was available for barely 0.5% of the Arctic coasts,” says Dr. Hugues Lantuit from the Alfred Wegener Institute (AWI). At the same time the geologist from AWI’s Potsdam Research Unit heads the international secretariat of the IPA and is also one of the coordinators of the study. After over ten years of intensive work we have now gained a comprehensive overview of the state and risk of erosion in these areas. “The Arctic is developing more and more into a mirror of various drivers of global change and into a focal point of national and worldwide economic interest,” says Dr. Hartwig Kremer, head of the LOICZ project office.
ScienceDaily (Feb. 26, 2011) — An international scientific team has shown that strong links between the corals reefs of the south China sea, West Pacific and Coral Triangle hold the key to preserving fish and marine resources in the Asia-Pacific region.
Research by Dr Johnathan Kool of the ARC Centre of Excellence for Coral Reef Studies and James Cook University, and his colleagues, has established that the richest marine region on Earth — the Coral Triangle between Indonesia, Malaysia and the Philippines — depends vitally for its diversity and resilience on coral and fish larvae swept in from the South China Sea and Solomon Islands.
“The currents go in various directions, but the prevailing direction is from east to west, and this carries coral spawn and fish larvae from areas such as round the Spratly Islands in the South China Sea and the Solomons/Papua New Guinea,” he explains.
“Maintaining the network of links between reefs allowing larvae to flow between them and re-stock depleted areas, is key to saving coral ecosystems threatened by human pressure and climate change.
“The Coral Triangle is home to more than one third of all the world’s coral reefs, including over 600 different species of reef-building coral and 3,000 species of reef fish. These coral ecosystems provide food and income for more than 100 million people working in marine based industries throughout the region,” Dr Kool explains.
“Knowing where coral spawn comes from is vital to managing our reefs successfully. Even though coral reef communities may not be connected directly to one another, reefs on the edge of the Coral Triangle have the potential to contribute significant amounts of genetic diversity throughout the region,” says Dr Kool.
He argues that recent evidence showing the region’s biology is closely inter-connected suggests it is in the interests of all Asia-Pacific littoral countries to work together more closely to protect it: “The science shows the region’s natural resources are closely interconnected. Nations need to co-operate to look after them — and that begins with recognising the resources are at risk and that collective action is needed to protect them.
Six nations within the Coral Triangle, (Indonesia, the Philippines, Malaysia, Papua New Guinea, The Solomon Islands and Timor L’Este) are now working together to strengthen coral reef governance and management, under an arrangement known as the Coral Triangle Initiative.
The paper “Connectivity and the development of population genetic structure in Indo-West Pacific coral reef communities” by Johnathan T. Kool, Claire B. Paris, Paul H. Barber and Robert K. Cowen appears in a recent issue of the journal Global Ecology and Biogeography.
Royal Caribbean Cruise Lines is using EcoReefs modules to create a shallow-water snorkeling reef at its Coco Cay shore excursion resort facility. Snorkeling is the resort’s most popular watersports concession, enjoyed by thousands of guests each year. 50 EcoReefs modules were installed in the Coco Cay lagoon area to create a colorful, engaging point-of-interest for snorkelers. The ecological development of the reef will be measured as part of an ongoing monitoring programme.
January 31st, 2011
A tourism organisation and a conservation organisation are teaming up to improve coral reef protection in the Caribbean:
A cooperation agreement was signed [last week] between the Organization of Latin-American and Caribbean Tourism (OLACT) and the Coral Reef Alliance (CORAL); both organizations will work together to implement conservation programs for the coral reefs and the marine life in Latin-America and the Caribbean.
Through the members of OLACT, both in the tourism and educational sector, CORAL will be able to share and disseminate the knowledge and tools developed throughout their long experience of working in reef zones in Hawaii, Mexico, Belize, Honduras, Fiji, and Indonesia.
Through its educational and financing components, OLACT will promote CORAL’s conservation tools and trainings to the tourism industry and will foster sustainable tourism programs to ensure the protection of the reefs by helping communities develop innovative local initiatives that conserve reefs and return tangible benefits to local communities. Finally the university partners of OLACT will leverage the trainings to help spread the educational messages about coral reef conservation throughout Latin-America and the Caribbean region.