Ocean VL 9 Flashcards
What makes plastic pollution particularly problematic in aquatic ecosystems?
Plastic pollution is problematic due to its durability, slow degradation, and widespread presence. It accumulates in marine environments, affecting marine organisms through ingestion, entanglement, and transport of toxins and invasive species.
What are the major types of plastics found in marine environments, and how do they differ in environmental behavior?
- Polyethylene (PE): Low density, floats, commonly used in packaging.
- Polypropylene (PP): Low density, floats, used in ropes and containers.
- Polystyrene (PS): Low density, floats, found in packaging and disposable products.
- Polyethylene Terephthalate (PET): High density, sinks, used in bottles and textiles. Their different densities influence how they behave in water (floating, sinking, or remaining suspended).
How does plastic ingestion affect marine species at different trophic levels?
Pelagic and benthic species ingest plastics depending on plastic concentration, distribution, and feeding behavior (filter feeders, predators).
Effects: Plastics may reduce nutrient uptake by diluting natural food sources, leading to malnutrition. They can also accumulate in the digestive tracts of organisms, impacting health.
Trophic Transfer: Plastics can move up the food chain through ingestion by predators, though biomagnification (increasing concentration at higher trophic levels) has not been confirmed.
What are the indirect ecological effects of plastics on marine organisms?
1) Phytoplankton: Plastic particles can attach to phytoplankton, altering their sinking rates, which affects nutrient cycling and the food supply to deeper waters.
2) Sediment: Plastics can blanket sediments, causing hypoxia or anoxia (lack of oxygen) in benthic habitats, leading to die-offs of bottom-dwelling species.
3) Temperature: Plastic debris can affect beach sand temperatures, influencing species like sea turtles whose sex ratios depend on incubation temperatures.
How do microplastics interact with phytoplankton, and what are the consequences for marine ecosystems?
Interaction: Microplastics can adhere to phytoplankton aggregates, particularly diatoms, altering their sinking behavior. This can cause blooms to persist longer in the photic zone, potentially affecting primary production and nutrient dynamics.
Consequences: Altered sinking rates mean less organic material reaches the ocean floor, disrupting deep-sea food webs and carbon sequestration.
How has plastic influenced the reproduction of the Pacific pelagic water strider?
Substrate Availability: Halobates sericeus (Pacific pelagic water strider) uses floating debris as egg-laying substrates. The increase in plastic debris has expanded available habitats, releasing the species from natural substrate limitation.
-> The increased reproduction can lead to changes in population dynamics and energy transfer within pelagic ecosystems, as predators consume more eggs…
What role do plastics play in altering beach sand temperature, and how does this impact species like sea turtles?
Thermal Effects: Plastics in beach sand can influence thermal conductivity. While some studies (e.g., Carson et al.) suggested slower heating, recent research (e.g., Fuentes et al.) found plastics may cause higher final temperatures due to their heat retention properties.
Impact on Sea Turtles: Sea turtle sex determination is temperature dependent. Higher temperatures lead to more female hatchlings, while lower temperatures result in more males. Plastics can, therefore, skew sex ratios in turtle populations.
How do plastics contribute to the spread of invasive species in marine environments?
Floating Rafts: Plastics provide durable floating surfaces for species like bryozoans, barnacles, and polychaetes to travel long distances, often from one region to another.
Species Example: Diadumene lineata (orange-striped anemone) has been transported from Asia to Hawaii, thriving in estuaries and sheltered waters. Plastics facilitate its spread by providing rafts for colonization.
Impacts: Invasive species can outcompete native fauna, leading to biodiversity loss and alterations in local ecosystems.
How do plastics contribute to the proliferation of harmful algal blooms (HABs)?
Plastic as a Substrate: Harmful algae such as dinoflagellates can colonize plastics, using them as a substrate for growth. Plastics can transport these organisms across different regions, contributing to the spread of HABs.
Effects: HABs produce toxins that harm marine life, and their increased spread due to plastic substrates can lead to more frequent and widespread toxic events, affecting marine food webs and human health.
ow do wastewater treatment plants (WWTPs) handle microplastics, and what are the potential environmental risks?
1) Microplastic Retention: WWTPs capture larger microplastics (>500 µm) but struggle to retain smaller particles, which can escape into water bodies through treated effluent.
2) Sewage Sludge: Microplastics accumulate in sewage sludge, which is often used as fertilizer in agriculture, potentially leading to land-based contamination and further spread of microplastics into aquatic systems.
What are the effects of biofilms forming on plastic surfaces in aquatic environments?
1) Food Source: Biofilms on plastics serve as food for grazing organisms, but their food quality is often lower than natural surfaces, affecting the growth and feeding activity of species like snails (Radix balthica).
2) Multi-Generational Effects: Prolonged exposure to plastic biofilms can have multi-generational impacts on grazing species, potentially affecting their population dynamics.
What are the different recycling methods for plastics, and what challenges do they face?
1) Primary Recycling: Mechanical reprocessing into products with equivalent properties.
2) Secondary Recycling: Mechanical reprocessing into lower-quality products.
3) Tertiary Recycling: Recovery of chemical constituents.
4) Quaternary Recycling: Energy recovery from burning plastics.
Challenges: Mixed waste streams, contamination, and the high energy cost of recycling processes can limit the efficiency and scalability of plastic recycling.
What are the key socioeconomic benefits and costs of plastics?
Benefits: Plastics improve food packaging, reduce transportation costs, enhance medical devices, and contribute to energy savings.
**Costs: **Despite these benefits, the environmental costs of plastic pollution, including ecosystem degradation, biodiversity loss, and human health risks, outweigh many of the economic gains.
What are the benefits and limitations of biodegradable plastics?
Benefits: Biodegradable plastics can reduce waste in landfills and oceans, and may have a lower carbon footprint compared to conventional plastics.
Limitations: They are not yet widely economical, can complicate recycling processes, and still contribute to CO2 emissions during production and degradation. Life cycle analyses and clear labeling are essential to ensure they are used effectively
How can citizen science contribute to addressing plastic pollution?
Initiatives: Programs like Plastikpiraten and Schone Rivieren engage citizens in collecting data, cleaning up plastic waste, and raising awareness.
Impact: These efforts help quantify plastic pollution, promote circular economies, and influence public policy by demonstrating the scale of the problem and potential solutions.
