Editing Marine plastic concentration

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! Object type
| Damage Signal
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! SIGNAL Earth ID
| DS-00736
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! Observable type
| —
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! Unit
| mixed concentration / count
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! Temporal structure
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! Monitoring backbone
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{{SignalTerm|type=DS|id=DS-00736|label=Marine plastic concentration}} refers to the measurement of plastic particles and debris present in the oceanic environment. This phenomenon encompasses a range of plastic materials, from microscopic fragments to larger debris, dispersed throughout marine waters globally. Understanding marine plastic concentration is critical for assessing the extent of plastic pollution and its potential impacts on marine ecosystems and human activities.

Plastic pollution in the marine environment originates from various sources, including land-based runoff, maritime activities, and direct dumping. The accumulation of plastics in oceans poses challenges to marine life, water quality, and coastal economies. Scientific study of marine plastic concentration aids in tracking pollution trends and informing environmental management.

Within the global environmental monitoring context, marine plastic concentration is a key indicator of anthropogenic influence on ocean health. It is monitored through a combination of field sampling, remote sensing, and modeling approaches to provide spatially and temporally resolved data on plastic abundance and distribution.

== Geographic / System Context ==
Marine plastic concentration is a global phenomenon affecting all ocean basins, from coastal zones to the open ocean, including surface waters, water columns, and seabed sediments. The distribution of plastic debris is influenced by ocean currents, wind patterns, coastal population density, and waste management practices. Regions such as ocean gyres, coastal estuaries, and river mouths often exhibit elevated concentrations due to accumulation and transport mechanisms. The marine environment serves as both a sink and conduit for plastic materials, linking terrestrial and marine ecosystems.

== Monitoring and Measurement ==
Monitoring marine plastic concentration involves a variety of scientific methods, including surface trawl sampling using nets designed to capture microplastics and larger debris, underwater visual surveys, and sediment sampling. Remote sensing technologies and aerial surveys complement in situ measurements by providing broader spatial coverage. Analytical techniques such as spectroscopy and microscopy are employed to characterize plastic types and sizes. Institutions involved in monitoring include marine research organizations, environmental agencies, and international collaborations focused on ocean health and pollution assessment.

Within the SIGNAL system, this phenomenon is treated as a defined environmental signal whose boundaries and measurement conventions are described below.

== Signal Definition ==
Marine plastic concentration is defined as the concentration or abundance of plastic particles and debris within the marine environment, measured within a specified spatial boundary and sampling frame. This includes all plastic materials detected in ocean waters, ranging from microplastics less than 5 millimeters in size to larger visible debris. The signal quantifies the presence of plastic pollution as a metric for environmental assessment and monitoring.

== Boundary Conditions ==
Boundary inclusions encompass plastic particles and debris present in the marine environment, including surface waters, water columns, and seabed sediments within the declared geographic and sampling limits. Exclusions apply to plastic materials located on land, in freshwater systems outside estuarine transition zones, or in marine areas beyond the defined spatial scope. The signal does not include non-plastic anthropogenic debris or natural materials unless contaminated with plastics.

== Aggregation Semantics ==
Geographic aggregation of marine plastic concentration data involves compiling measurements across defined oceanic regions or global extents to assess spatial distribution patterns. Temporal aggregation considers the integration of data over specified time intervals to evaluate trends and seasonal variability. Cross-signal aggregation may involve correlating marine plastic concentration with related environmental signals such as biota toxic contaminant burden or coastal litter accumulation density to understand combined ecological impacts. Aggregation methods aim to standardize data for comparative and integrative analyses across scales.

== Observational Status ==
Current monitoring of marine plastic concentration is ongoing but varies in spatial and temporal resolution due to methodological and logistical constraints. Data availability is improving with advances in sampling technologies and international coordination. Future SIGNAL releases may incorporate enhanced temporal structures, standardized units, and integration with complementary environmental signals to provide a more comprehensive understanding of plastic pollution dynamics in marine systems.

== Related Signals ==
* Biota toxic contaminant burden
* Coastal litter accumulation density
* Coral reef live cover fraction
* Fish catch (mass)
* Mangrove area extent
* Marine fish biomass stock (declared species group)
* Mortality count (organisms)
* Municipal solid waste leakage rate

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== Key Associated People ==
* '''Gabriel Erni-Cassola''' — University of Warwick [Source author; High]
* '''Peter T. Harris''' — University of Rhode Island [Source author; High]

Inclusion reflects material contribution to the scientific understanding of this damage signal; it does not imply review, endorsement, or affiliation with SIGNAL Earth.
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== Sources ==
* [https://www.sciencedirect.com/science/article/pii/S0278434323000249 A marine plastic cloud - Global mass balance assessment of oceanic plastic pollution] — Continental Shelf Research, 2023. DOI: 10.1016/j.csr.2023.104947. [Paper; Supporting; High]
* [https://www.sciencedirect.com/science/article/pii/S0304389419301979 Distribution of plastic polymer types in the marine environment; A meta-analysis] — Journal of Hazardous Materials, 2019. DOI: 10.1016/j.jhazmat.2019.02.067. [Paper; Supporting; High]
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