New study ranks 'hotspots' of human impact on coastal areas

Jul 09, 2009
Global hotspots where human activities on land are impacting coastal marine ecosystems. The numbers show the rank order of the hottest hotspots (red dots). The blue and green dots are land-based activities that are having an important effect on marine systems but not as much as those areas marked by the red dots. Credit: B. Halpern and colleagues, NCEAS

(Santa Barbara, Calif.) -- Coastal marine ecosystems are at risk worldwide as a result of human activities, according to scientists at UC Santa Barbara who have recently published a study in the Journal of Conservation Letters. The authors have performed the first integrated analysis of all coastal areas of the world.

"Resource management and conservation in coastal waters must address a litany of impacts from human activities, from the land, such as urban runoff and other types of pollution, and from the sea," said Benjamin S. Halpern, first author, who is based at the National Center for Ecological Analysis and Synthesis (NCEAS) at UCSB.

"One of the great challenges is to decide where and how much to allocate limited resources to tackling these problems," he said. "Our results identify where it is absolutely imperative that land-based threats are addressed -- so-called hotspots of land-based impact -- and where these land-based sources of impact are minimal or can be ignored."

The hottest hotspot is at the mouth of the , explained Halpern, with the other top 10 in Asia and the Mediterranean. "These are areas where conservation efforts will almost certainly fail if they don't directly address what people are doing on land upstream from these locations."

The hottest hotspot of land-based impact on marine ecosystems is the Mississippi River. The river plume is shown here as seen from space. Credit: NASA

Nutrient runoff from upstream farms has caused a persistent "dead zone" in the Gulf of Mexico, where the Mississippi runs into this body of water. The dead zone is caused by an overgrowth of algae that feeds on the nutrients and takes up most of the oxygen in the water.

The authors state that they have provided the first integrated analysis for all coastal areas of the world. They surveyed four key land-based drivers of ecological change:

  • nutrient input from agriculture in urban settings
  • derived from pesticides
  • inorganic pollutants from urban runoff
  • direct impact of human populations on coastal marine habitats.
Halpern explained that a large portion of the world's coastlines experience very little effect of what happens on land -- nearly half of the coastline and more than 90 percent of all coastal waters. "This is because a vast majority of the planet's landscape drains into relatively few very large rivers, that in turn affect a small amount of coastal area," said Halpern. "In these places with little impact from human activities on land, marine can and needs to focus primarily on what is happening in the ocean. For example: fishing, climate change, invasive species, and commercial shipping."

Source: University of California - Santa Barbara (news : web)

Explore further: Far more displaced by disasters than conflict

add to favorites email to friend print save as pdf

Related Stories

Corals reveal impact of land use

May 31, 2007

Using the corals on the Great Barrier Reef (GBR) as a history book, researchers have linked land use along the coast to decades of declining water quality and poor coral health.

Recommended for you

Far more displaced by disasters than conflict

35 minutes ago

Disasters last year displaced three times more people than violent conflicts, showing the urgent need to improve resilience for vulnerable people when fighting climate change, according to a study issued ...

Coral growth rate plummets in 30-year comparison

7 hours ago

A team of researchers working on a Carnegie expedition in Australia's Great Barrier Reef has documented that coral growth rates have plummeted 40% since the mid-1970s. The scientists suggest that ocean acidification ...

Environmentalists and industry duke it out over plastic bags

8 hours ago

Campaigns against disposable plastic shopping bags and their environmental impact recently scored a major win. In August, California lawmakers passed the first statewide ban on the bags, and Governor Jerry Brown is expected ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

omatumr
1 / 5 (1) Jul 11, 2009
THIS IS SCIENCE?

"Coastal marine ecosystems are at risk worldwide as a result of human activities."

Are those living on the coast of California in Santa Barbara willing to make the supreme sacrifice?

That's my opinion!
Oliver K. Manuel
http://myprofile....anuelo09
or http://www.omatumr.com