Scientists estimate total weight of plastic floating in world's oceans: Nearly 269,000 tons of plastic pollution floating in the ocean

Model results for global count density in four size classes. Model prediction of global count density (pieces km−2; see colorbar) for each of four size classes (0.33–1.00 mm, 1.01–4.75 mm, 4.76–200 mm, and >200 mm). Credit: Marcus Eriksen et al, PLoS ONE, 2014; DOI: 10.1371/journal.pone.0111913

Nearly 269,000 tons of plastic pollution may be floating in the world's oceans, according to a study published December 10, 2014 in the open-access journal PLOS ONE by Marcus Eriksen from Five Gyres Institute and colleagues.

Microplastic pollution is found in varying concentrations throughout the oceans, but estimates of the global abundance and weight of floating plastics, both micro and macroplastic, lack sufficient data to support them. To better estimate the total number of plastic particles and their weight floating in the world's oceans, scientists from six countries contributed data from 24 expeditions collected over a six-year period from 2007-2013 across all five sub-tropical gyres, coastal Australia, Bay of Bengal, and the Mediterranean Sea. The data included information about microplastics collected using nets and large plastic debris from visual surveys, which were then used to calibrate an ocean model of plastic distribution.

Based on the data and model, the authors of the study estimate a minimum of 5.25 trillion plastic particles weighing nearly 269,000 tons in the world's oceans. Large plastics appear to be abundant near coastlines, degrading into microplastics in the 5 subtropical gyres, and that the smallest microplastics were present in more remote regions, such as the subpolar gyres, which the authors did not expect. The distribution of the smallest microplastics in remote regions of the ocean may suggest that gyres act as 'shredders' of large plastic items into microplastics, after which they eject them across the ocean.

"Our findings show that the garbage patches in the middle of the five subtropical gyres are not the final resting places for the world's floating plastic trash. The endgame for micro-plastic is interactions with entire ocean ecosystems," says Marcus Eriksen, PhD, Director of Research for the 5 Gyres Institute.

Source: PLOS

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Recreational activity a major pollutant on Canadian coast of Pacific Ocean

This is University of Calgary associate professor in geography Stefania Bertazzon.
Credit: Robert Walker

From recreational boats and fishing vessels to commercial cruise ships and private marinas, a newly published study shows that oil discharges related to human maritime activity on the Canadian coast is posing a major threat to marine ecosystems in the Pacific Ocean.

The study -- published in the August edition of the journal Applied Geography, with University of Calgary associate professor in geography Stefania Bertazzon as lead author -- provides a geospatial analysis of oil discharges in the Canadian Pacific Ocean.

The findings show that a large portion of oil discharge within these waters stems from recreational activities, passenger traffic and fisheries. According to this scientific analysis -- conducted on oil spills observed by the National Aerial Surveillance Program with the use of remote sensing devices -- these sources are polluting the ocean along the British Columbia coast more than oil tankers and commercial cargo ships.

"Cargo ships and oil tankers are much more regulated with portside inspections and they have to meet certain standards," explains Bertazzon. "They're very aware of this surveillance and this is probably why our analysis suggests that they are responsible for a smaller portion of detected oil discharges. They have to be more careful."

Bertazzon adds: "We're not saying that cargo ships and oil tankers are not polluting. What we are saying is that they are not the only source of pollution in the Canadian Pacific Ocean."
Bertazzon and her co-authors explain that fuel docks for recreational and fishing vessels can be problematic. "We know that there's a lot of oil discharge in these fuel docks, which is largely uncontrolled," she says.

"One thing that happens in these marinas is there's a lot of old boats which have been sitting there for years slowly leaking into the ocean. These are not huge spills. It's a relatively small discharge. But there's a lot of these derelict vessels and together they make for a large source of pollution."

While there's no denying the impact of large-scale oil industry disasters such as the Gulf of Mexico spill in 2010, Bertazzon argues that the oil discharges related to maritime activities are even more devastating to marine ecosystems in the long run.
"There is scientific evidence to show that these day to day activities have a larger impact on the wild life and the marine ecosystem than those accidents that are huge, but limited in space and time," says Bertazzon. "What we're talking about happens every day, all along the coast. The impact is longer term and over a larger spatial extent."

Source:  University of Calgary

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Deepwater Horizon spill: Much of the oil at bottom of the sea

Controlled burning of surface oil slicks during the Deepwater Horizon event.
Credit: David Valentine

Due to the environmental disaster's unprecedented scope, assessing the damage caused by the 2010 Deepwater Horizon spill in the Gulf of Mexico has been a challenge. One unsolved puzzle is the location of 2 million barrels of submerged oil thought to be trapped in the deep ocean.

UC Santa Barbara's David Valentine and colleagues from the Woods Hole Oceanographic Institute (WHOI) and UC Irvine have been able to describe the path the oil followed to create a footprint on the deep ocean floor. The findings appear today in the Proceedings of the National Academy of Sciences.

For this study, the scientists used data from the Natural Resource Damage Assessment process conducted by the National Oceanic and Atmospheric Administration. The United States government estimates the Macondo well's total discharge -- from the spill in April 2010 until the well was capped that July -- to be 5 million barrels.

By analyzing data from more than 3,000 samples collected at 534 locations over 12 expeditions, they identified a 1,250-square-mile patch of the deep sea floor upon which 2 to 16 percent of the discharged oil was deposited. The fallout of oil to the sea floor created thin deposits most intensive to the southwest of the Macondo well. The oil was most concentrated within the top half inch of the sea floor and was patchy even at the scale of a few feet.

The investigation focused primarily on hopane, a nonreactive hydrocarbon that served as a proxy for the discharged oil. Researchers analyzed the spatial distribution of hopane in the northern Gulf of Mexico and found it was most concentrated in a thin layer at the sea floor within 25 miles of the ruptured well, clearly implicating Deepwater Horizon as the source.

"Based on the evidence, our findings suggest that these deposits come from Macondo oil that was first suspended in the deep ocean and then settled to the sea floor without ever reaching the ocean surface," said Valentine, a professor of earth science and biology at UCSB. "The pattern is like a shadow of the tiny oil droplets that were initially trapped at ocean depths around 3,500 feet and pushed around by the deep currents. Some combination of chemistry, biology and physics ultimately caused those droplets to rain down another 1,000 feet to rest on the sea floor."

Valentine and his colleagues were able to identify hotspots of oil fallout in close proximity to damaged deep-sea corals. According to the researchers, this data supports the previously disputed finding that these corals were damaged by the Deepwater Horizon spill.

"The evidence is becoming clear that oily particles were raining down around these deep sea corals, which provides a compelling explanation for the injury they suffered," said Valentine. "The pattern of contamination we observe is fully consistent with the Deepwater Horizon event but not with natural seeps -- the suggested alternative."

While the study examined a specified area, the scientists argue that the observed oil represents a minimum value. They purport that oil deposition likely occurred outside the study area but so far has largely evaded detection because of its patchiness.

"This analysis provides us with, for the first time, some closure on the question 'Where did the oil go and how?' " said Don Rice, program director in the National Science Foundation's Division of Ocean Sciences. "It also alerts us that this knowledge remains largely provisional until we can fully account for the remaining 70 percent."

"These findings should be useful for assessing the damage caused by the Deepwater Horizon spill as well as planning future studies to further define the extent and nature of the contamination," Valentine concluded. "Our work can also help to assess the fate of reactive hydrocarbons, test models of oil's behavior in the ocean and plan for future spills."

Co-authors are G. Burch Fisher and Sarah C. Bagby, postdoctoral researchers in the Valentine Lab at UCSB; Robert K. Nelson, Christopher M. Reddy and Sean P. Sylva of WHOI; and Mary A. Woo of UC Irvine. The research was funded by the National Science Foundation.

Source:  University of California - Santa Barbara

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Colorado River Delta greener after engineered pulse of water

Water being released from Morelos Dam in the first environmental release of water to the Colorado River Delta. The Minute 319 pulse flow of water started March 23, 2014 and ended May 18, 2014. Credit: Rebecca Lester, Deakin University, Australia

The engineered spring flood that brought water to previously dry reaches of the lower Colorado River and its delta resulted in greener vegetation, the germination of new vegetation along the river and a temporary rise in the water table, according to new results from the binational team of scientists studying the water's effects.

The experimental pulse flow of water was the result of a U.S.-Mexico agreement called Minute 319.

"The pulse flow worked," said Karl W. Flessa, co-chief scientist for the Minute 319 Science Team. "A small amount of water can have a big effect on the delta's ecosystem."Starting March 23, 2014, and ending May 18, approximately 105,392 acre-feet (130 million cubic meters) of water was released into the dry river bed below Morelos Dam, which straddles the U.S.-Mexico border just west of Yuma.

"The groundwater was recharged, vegetation got greener than previous years and the water helped germinate new native vegetation," said Flessa, a University of Arizona professor of geosciences. "As a bonus, the river reached the sea."

In addition, people living along the river benefited, he said.

"People in the communities along the river were just overjoyed to see their river again," he said. "When the surface water was there, people celebrated. Kids who'd never seen water in the river before got to splash in it."

The science team includes more than 21 scientists from universities, government agencies and nongovernmental organizations from both Mexico and the U.S, including the UA, the Universidad Autónoma de Baja California, the U.S. Geological Survey, the U.S. Bureau of Reclamation, The Nature Conservancy, the Tucson-based Sonoran Institute and the Ensenada-based Pronatura Noroeste.

Flessa will present the team's findings at his talk, "The Science and Policy of the First Environmental Flows to the Colorado River Delta," on Dec. 18 as part of the American Geophysical Union's annual meeting in San Francisco.

Although most of the water soaked into the ground in the 37 miles (60 km) below the dam, the river's surface flow reached areas farther downstream that had been targeted for restoration. The increase in groundwater revived vegetation along the entire 83-mile (134 km) route to the sea.

By comparing Landsat 8 satellite images from August 2013 with those from August 2014, team members calculated a 23 percent increase in the greenness of riparian zone vegetation.
Although the groundwater did eventually recede, the surface water caused the germination of new willows and cottonwoods. Those plants germinate after natural spring floods, and their roots can grow fast enough to keep up with the receding water table.

The surface water reached the restoration sites prepared by the Sonoran Institute and Pronatura Noroeste and helped establish native vegetation.

"So long as the roots get down into the permanent water table, then you have established a new bunch of trees that will then live for 20, 30, 40 years," Flessa said. "Those trees will attract birds."

The scientists already observed an increase in the numbers of birds, he said.
Learning where the newly germinated plants survived past the first summer will help the researchers figure out where ecosystem restoration will do the most good using the least amount of water, he said.

"The water that soaked into the ground is also good for the farmers," Flessa said. "It raises the water table and they pump that water -- so this isn't just about trees and birds."
The team will continue to monitor the lower Colorado River Delta's vegetation and hydrological response to the pulse flow, including the long-term effect on groundwater. They will also study how the new vegetation affects both resident birds and those migrating along the Pacific Flyway.

The five-year program to monitor the environmental results of the pulse flow is being supported by government agencies and environmental groups in both countries, under the auspices of the International Boundary and Water Commission.

The Minute 319 pulse flow is part of a five-year agreement (2012-17) adopted by the International Boundary and Water Commission, under the framework of a 1944 U.S. -- Mexico treaty that governs water allocations on the Colorado River between the two countries.

The agreement provides multiple benefits for Colorado River water users in both countries, including environmental flows to the delta. Minute 319 identifies criteria for sharing of future water shortages and surpluses between the two countries, allows storage of Mexican water in Lake Mead and supports improvements to Mexican irrigation infrastructure.
"Another pulse flow would require a new agreement, because Minute 319 calls for only one pulse flow within the five-year term of the minute," Flessa said. "We hope the results of this pulse flow encourage the negotiators to make this happen again."

Source: University of Arizona

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New technology successfully removes heavy metals from water

Polluted water.
Credit: Image courtesy of Investigación y Desarrollo

The methods traditionally used to remove heavy metals from wastewater have limitations because they only withdraw a certain percentage and the remaining amount is very difficult to remove. This motivated a young graduate researcher at the National Polytechnic Institute (IPN) in Mexico, Gabriel Ramirez Monter, to create a technology capable of removing such contaminants at low cost and with an efficiency that surpasses existing technologies.

According to Monter Ramirez, this project led him to design some structures called dendrimers, which are highly branched molecules with shape similar to a shrub or a tree with multiple branches.
"Dendrimers adhere and spread on a microfiltration membrane; ie, thin sheets of porous material that are not normally capable of retaining heavy metals due to its pore size. Once placed, it achieves total removal of heavy metal ions in the same way a marine anemone would act, using tentacles to concentrate and catch food; in this case, the branches of the dendrimers capture pollutants, "says the researcher.

He explains that through dendrimers the team converted a microfiltration membrane into a nanofiltration one. "Another advantage of these structures is that they can be washed and reused, plus the captured metals are removed without problem."

Highlighting his business plan, which he called "Nanoestructurados Bromelia", it integrates his master's work, led by Dr. Irina Victorovna Lijanova attached to the Centre for Research and Technological Innovation (CIITEC) of the IPN, which has optimized technologies for removal of heavy metals.

Currently, the entrepreneurial project is linked to the company "Nanotecnología México" that specializes in nanomaterials with applications for the environment and is a leading provider of Mexican Oil (Pemex) in the refining area for sewage cleanup. "The firm was interested in the development of this technology and its commercialization," said Monter Ramirez.

"In Mexico, the problem of heavy metals is associated with industrial progress and important economic activities such as mining or even the oil industry, in both refining and petrochemicals; those are the markets we want to focus on," he stresses.

Source: Investigación y Desarrollo.

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