52 Matching Annotations
  1. Jul 2018
    1. Weathering

      Weathering is when pieces of plastic are mechanically broken up into smaller pieces. This is a problem because marine organisms can eat the smaller pieces but are unable to digest them. See the annotation for reference 16 for more information.

    2. M. C. Goldstein, D. S. Goodwin, PeerJ 1, e184 (2013).

      An ocean gyre is a circular ocean current formed by the Earth’s wind patterns and rotation. The area in the center of a gyre tends to be very calm, and the circulation patterns of the currents draw debris into the stable center, where it becomes trapped. The debris is composed of objects both manmade and natural (i.e. driftwood). Many kinds of sea life live on and near the debris. Gooseneck barnacles are one of these types of organism. Goldstein and Goodwin examined the digestive tracts of gooseneck barnacles to see if the barnacles consumed any plastics. One third of the 385 barnacles examined had plastic particles present in their digestive tracts, and larger barnacles tended to contain more plastic particles. The effects of the plastic particle ingestion on the ecosystem are still unknown.

    3. Arctic sea ice

      Ice covers the Arctic Ocean. Over the course of a year, ice increases during fall and winter and melts during spring and summer. All of the ice does not melt entirely during the spring and summer; some of the ice persists from one year to the next.

    4. the cumulative quantity of plastic waste available to enter the ocean from land is predicted to increase by an order of magnitude by 2025

      It is hoped that this number can be minimized through improved waste management techniques and infrastructure.

    5. waste management infrastructure

      Waste management infrastructure is the collection of processes and facilities that properly dispose of wastes and reduce pollution. A major goal of waste management is often to reduce the amount of waste deposited in landfills by reuse or recycling.

    6. Improving waste management infrastructure in developing countries is paramount and will require substantial resources and time. While such infrastructure is being developed, industrialized countries can take immediate action by reducing waste and curbing the growth of single-use plastics.

      This paper connects to Vision and Change Core Competencies and Disciplinary Practices 6 by presenting the ecological consequences of marine plastic pollution in a societal context.

    7. Plastics in the marine environment are of increasing concern

      This paper connects to Vision and Change Core Competencies and Disciplinary Practices 3 and 4 by using modeling and emphasizing the interdisciplinary nature of science.

    8. It is widely cited that 80% of marine debris originates from land; however, this figure is not well substantiated and does not inform the total mass of debris entering the marine environment from land-based sources.

      The article connects to the Learning Standards, Common Core: Statistics and Probability (Construct viable arguments and critique the reasoning of others).

    9. The inclusion of the economic cost of implementation, as well as socio-cultural, environmental, and other factors that affect infrastructure development or behavioral change, would improve the evaluation of mitigation strategies

      This paper connects to the English Language Arts Standards 11-12.1. It analyzes the problem of plastic waste in the ocean and explains the method used to estimate which countries likely generate most of the waste. The authors describe the sources of uncertainty in their estimates, and this paper also identifies strategies for reducing the amount of plastic waste entering the ocean in the future.

    10. By applying a range of conversion rates from mismanaged waste to marine debris, we estimated the mass of plastic waste entering the ocean from each country in 2010, used population growth data (13) to project the increase in mass to 2025, and predicted growth in the percentage of waste that is plastic.

      The authors developed a model to represent a large-scale system. Next Generation Science Standards: Connects to Practice 2: Developing and using models www.nap.edu/openbook.php?record_id=13165&page=42A

    11. market sector

      Market sector is an economics term that describes a part of the economy made up of multiple industries. Examples of market sectors include energy, health care, consumer goods, media, utilities, etc.

  2. May 2018
    1. We estimated the annual input of plastic to the ocean from waste generated by coastal populations worldwide.

      Exact numbers are not available for the mass of plastic waste entering the ocean, so the authors used a series of estimates in their calculations.

    2. We calculate that 275 million metric tons (MT) of plastic waste was generated in 192 coastal countries in 2010, with 4.8 to 12.7 million MT entering the ocean.

      The range of 4.8 to 12.7 million Metric Tons of waste comes from uncertainty in the total amount of waste generated, the amount of that waste that is plastic, and the amount of mismanaged waste that enters the ocean.

    3. The discharge of plastic from at-sea vessels has since been banned

      There is international recognition that plastic pollution in the ocean is a global problem, and policy decisions by governments have worked to address it.

    4. Reports of plastic pollution in the ocean first appeared in the scientific literature in the early 1970s

      Plastic pollution in the ocean has been known to be a problem for a long time.

    5. In 1975

      This early work (reference 1) looked at which types of pollutants might pose a future threat to ocean resources and mechanisms of how each pollutant ended up in the ocean.

    6. per capita

      Per capita is a Latin phrase which means for each person. Here, the authors are looking at the mass of waste generated per person per year.

    7. fragmentation

      Fragmentation is the process of being broken into smaller pieces or parts.

    8. tons

      A standard ton is 2000 pounds, while a metric ton is 1000 kilograms (2205 pounds).

    9. widely documented

      The Jambeck et al. paper focuses on sources of plastic waste entering the oceans. A 2018 publication from Lebreton et al. presents research on the size of the Great Pacific Garbage Patch, a collection of plastic waste floating halfway between California and Hawaii. The patch contains about 1.8 trillion pieces of plastic, collectively weighing 88,000 tons (more than 500 jumbo jets) and covering an area more than 600,000 square miles (more than twice the size of Texas) in extent. The plastic is "collected" by winds and ocean currents.

      For more information, see these links: https://www.usatoday.com/story/tech/science/2018/03/22/great-pacific-garbage-patch-grows/446405002/ and https://www.nature.com/articles/s41598-018-22939-w

  3. Feb 2018
    1. A. Cózar et al., Proc. Natl. Acad. Sci. U.S.A. 111, 10239–10244 (2014).

      This research examined the sizes and locations of plastic particles found in the world's oceans. When plastic objects in the ocean are exposed to sunlight, they tend to break up into small particles because the sunlight weakens the plastic structure and waves provide mechanical force. The small plastic particles are quite durable. Most of the plastic debris recovered and measured during this study was about 2 mm in diameter. The total amount of plastic in the ocean estimated by this study was less than predicted from plastics production and input rates. The "missing" plastics were hypothesized to be removed through one or more of the following processes: shore deposition (being deposited on shore somewhere), nano-fragmentation (breaking up into very small pieces), biofouling (small organisms grow on the plastic particles, and the plastics become heavy enough to sink), and ingestion (being consumed by marine life). The pathway and fate of the "missing" plastic is unknown.

    2. H. S. Carson et al., Mar. Environ. Res. 84, 76–83 (2013).

      This study looked at the sources and fate of local marine debris near the Hawaiian islands. Debris from a large community was captured using surface traps, and wooden drifters were released to examine the effect of nearshore currents and tides on debris distribution. This study demonstrated that local pollutants can be retained nearby, contribute to the island's debris-accumulation area, and quickly spread to other islands.

    3. R. W. Obbard et al., Earth’s Future 2, 315–320 (2014).

      When sea ice forms, it traps particulate matter from the water column such as microplastics. When sea ice melts, the particulate matter is released back into the ecosystem. This study examines the concentration of microplastics in Arctic Sea ice and finds that sea ice contains high concentrations of microplastics and other man-made particulates. Melting sea ice has the potential to release large amounts of microplastics back into the ocean.

    4. R. E. Marshall, K. Farahbakhsh, Waste Manag. 33, 988–1003 (2013).

      This article compares and contrasts solid waste management (SWM) practices in developed versus developing countries. SWM practices in industrialized countries are often affected by public health, the environment, resource scarcity, climate change, and public awareness and participation. However, urbanization, inequality, economic growth and socio-economic factors often complicate SWM in developing countries.

    5. M. Braungart, Nature 494, 174–175 (2013).

      This article discusses the idea of designing buildings and objects to be made using the minimum of materials and a maximum of efficiency. 3D printing and biodegradable materials are explored as examples of ways to improve product design and reduce waste.

    6. “2013 resin review” (American Chemistry Council, Washington, DC, 2013).

      This document released by the American Chemistry Council is a reference book on plastic resins. It contains information about North American resin production, sales, industry capacities, and utilization rates from 2002-2012. Sales data are presented for various end-use markets, and tables show historical trends from 1973 to 2012. The publication explains the basic chemistry of plastics and manufacturing processes. It also details the history of plastics development and modern-day applications and provides a glossary of basic plastics terms. Jambeck et al. used this reference to estimate the amounts of plastic production in North America and plastic in the U.S. waste stream.

    7. Our framework was designed to compute, from the best-available data, an order-of-magnitude estimate of the amount of mismanaged plastic waste potentially entering the ocean worldwide.

      Here the authors restate what the goal of their investigation was.

    8. polypropylene

      Polypropylene is a plastic polymer used in packaging, reusable containers, laboratory equipment, and medical devices. It is a polymer made of repeating subunits (groups of atoms) with three carbons in each subunit. Polypropylene is the second-most widely produced synthetic plastic, after polyethylene.

    9. polyethylene

      Polyethylene is a polymer, made of repeating subunits (groups of atoms) with two carbons in each subunit. It is the most commonly produced plastic in the world, used in applications such as plastic bags, films, and bottles.

    10. order of magnitude

      An order of magnitude is a comparison of size used when the item being compared is ten times larger or smaller than the item it is being compared to. The difference between 1 and 10 is an order of magnitude, as is the difference between 10 and 100. The difference between 1 and 100 is 2 orders of magnitude, and the difference between 1 and 1000 is 3 orders of magnitude.

  4. Jan 2018
    1. R. C. Thompson, C. J. Moore, F. S. vom Saal, S. H. Swan, Philos. Trans. R. Soc. London Ser. B 364, 2153–2166 (2009).

      This review article summarizes the uses humans have for plastics, the effects of plastics on the living and nonliving parts of the environment, and future concerns about the manufacture and disposal of plastic products.

    2. Materials and methods are available as supplementary materials on Science Online.

      Articles in Science are very brief. Supplementary materials available online can include text or images such as figures and graphs. Supplementary materials can provide additional information about how the research was conducted or additional evidence that supports the article's conclusions.

    3. “Probabilistic projections of total population: Median and confidence intervals,” (United Nations, Department of Economic and Social Affairs, New York, 2012); http://esa.un.org/unpd/ppp/Data-Output/ UN_PPP2010_output-data.htm.

      This population growth data from the United Nations was used to predict future amounts of plastic waste entering the ocean from individual countries.

    4. Sources of uncertainty in our estimates result from the relatively few measurements of waste generation, characterization, collection, and disposal, especially outside of urban centers. Even where data were available, methodologies were not always consistent, and some activities were not accounted for, such as illegal dumping (even in high-income countries) and ad hoc recycling or other informal waste collection (especially in low-income countries). In addition, we did not address international import and export of waste, which would affect national estimates but not global totals.

      Another important part of science is recognizing sources of uncertainty in the data that lead to uncertainty in the results.

    5. Alternatively, reduced waste generation and plastic use would also decrease the amount of mismanaged plastic waste.

      A United Nations resolution seeks to “prevent and significantly reduce marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution” by 2025.

      For more information, see this link: http://www.telegraph.co.uk/science/2017/12/13/193-nations-sign-pledge-tackle-global-crisis-plastic-oceans/

    6. potential mitigation strategies

      Addressing the problem of plastic waste in the ocean can be approached from two sides: allowing less waste to enter the ocean or collecting the waste after it has entered the ocean. Many proposals have been developed for ways to clean up trash after it arrives in the oceans. One small-scale approach uses a submerged garbage can that pumps water through a filter and captures debris, while one large-scale approach relies on deploying a 1-2 km long floating tube that gathers and concentrates floating plastic debris for eventual transport back to land and recycling.

      Read more about these approaches: https://www.theguardian.com/sustainable-business/2016/mar/30/seabin-ocean-pollution-epa-marina-miami-garbage and https://www.theoceancleanup.com/.

    7. Because no global estimates exist for other sources of plastic into the ocean (e.g., losses from fishing activities or at-sea vessels, or input from natural disasters), we do not know what fraction of total plastic input our land-based waste estimate represents

      An important part of science is recognizing the limits of the conclusions that can be drawn from a given data set.

    8. Our estimate of plastic waste entering the ocean is one to three orders of magnitude greater than the reported mass of floating plastic debris in high-concentration ocean gyres and also globally

      The authors' estimate of plastic waste entering the ocean is between 10 and 1000 times greater than the previously reported amount of waste floating in the ocean.

    9. 31.9 million MT were classified as mismanaged and an estimated 4.8 to 12.7 million MT entered the ocean in 2010, equivalent to 1.7 to 4.6% of the total plastic waste generated in those countries

      The authors predicted the amount of plastic waste that entered the ocean from coastal regions in 2010.

    10. we estimate that 99.5 million MT of plastic waste was generated in coastal regions in 2010

      The authors calculated the mass of plastic waste that came from coastal regions in 2010.

    11. This estimate is broadly consistent with an estimated 1.3 billion MT of waste generated by 3 billion people in urban centers globally

      Other authors have estimated similar amounts of waste generated by humans.

    12. We estimate that 2.5 billion MT of municipal solid waste was generated in 2010 by 6.4 billion people living in 192 coastal countries (93% of the global population).

      Using population density data and waste generation rates, the authors estimated the total amount of solid waste generated in 2010 by people living in coastal countries.

    13. Plastic debris

      Plastic debris is plastic waste that has accidentally or deliberately been released into the marine or terrestrial environment.

    14. population density

      Population density is a measurement of how many people live in a particular area. It is often expressed as people per square mile or kilometer. A city is a location with a high population density, while a desert is a location with low population density.

    15. waste management

      Waste management is the set of systems required to manage waste from when it is created to when it is finally disposed of. Steps of waste management include collection, transport, treatment, and disposal.

    16. flux

      Flux is a measurement of the quantity of an object that passes from one place to another. Here, flux is the total amount of litter that traveled from land to ocean in one year.

    17. plastic resin

      Plastic resin beads are the raw materials from which items such as plastic water bottles are made.

    18. MT

      A MT (metric ton) is a unit of weight equal to 1,000 kilograms (2,205 lb).

    19. persistence

      In this context, persistence means that the plastic materials are very stable and resistant to degradation.

    20. mitigation

      Mitigation is an action that reduces the severity or seriousness of a problem.

    21. extrapolated

      Extrapolation is the process of extending a graph or range of values by predicting unknown values from trends in the known data.

    22. Here we present a framework to calculate the amount of mismanaged plastic waste generated annually by populations living within 50 km of a coast worldwide that can potentially enter the ocean as marine debris.

      The authors use population density data and waste accumulation rates to predict how much plastic might enter the ocean as marine debris.