Pollution Overview

Pollution Overview

• Pollution has both short-term (acute) and long-term (chronic) effects on ecosystems.
• Long-term effects: Continuous low-level introduction of pollutants (e.g., nutrient input from sewage outfalls).
• Short-term effects: Temporary pollutants that dissipate over time (e.g., oil spills).

Spatial Patterns of Pollution

• Point Source Pollution:

  • Defined as the discharge of pollutants from a single identifiable source (e.g., sewer pipes, industrial outfalls).
  • Concentration decreases with increasing distance from the point source, allowing easier management.

• Non-Point Source Pollution:

  • Refers to diffuse sources of pollution, such as runoff after rainfall, which is more challenging to manage.

Effects of Pollution on Single Species

• Pollution can significantly affect the physiology and reproduction of organisms.
• Species vulnerability can be gauged using bioindicators like the mussel Mytilus.
• Bioassays: Used to assess mortality rates, growth potential, and reproduction under polluted conditions.
• Microarray techniques: Allow analysis of gene expression as a response to pollution.

Effects on Communities

• Organisms vary in their uptake and release rates of toxins.
• Trophic transfer can lead to the accumulation of toxins as they move up the food chain, a process known as biomagnification.
• Example: DDT accumulates from invertebrates through fish to birds.

DDT and Biomagnification Example

• Concentrations of DDT in different organisms:
  • Algae/Plants: 0.04 ppm
  • Plant-eating Fish: 0.2-1.2 ppm
  • Large Fish: 1-2 ppm
  • Fish-eating Birds: 3-76 ppm

Effects on Biodiversity

• Pollution leads to a decrease in biodiversity, both in species numbers and their relative abundance.
• Pollution-tolerant species often thrive, while sensitive species decline.

Ocean Debris

• Oceans are seen as dumping grounds for human waste, leading to significant ecological effects even from small amounts of debris.

Types of Marine Pollution

• Various sources of debris polluting marine environments:
  • Shoreline Activities: Food wrappers, beverage containers, toys.
  • Ocean Activity: Fishing gear, plastic sheeting, crates.
  • Medical/Hygiene Waste: Tampons, diapers, batteries.
  • Statistics indicate significant percentages from different categories:
  • Medical and Personal Hygiene: 1.5%
  • Dumping Activities: 2.8%
  • Smoking-Related Activities: 35.8%
  • Shoreline and Recreational Activities: 52%.

Plastics in the Ocean

• Plastics are long-lasting materials that often wash ashore. Major sources include discarded fishing gear and trash.
• Pelagic Plastics: Concentrate in gyres (e.g., Great Pacific Garbage Patch).
  • Microplastics can be found at concentrations 7 times greater than zooplankton.
• Photodegradation: Reduces particle size and releases harmful chemicals like BPA and PCBs.

Marine Animals and Plastics

• Marine animals can become entangled, risking drowning or starvation (ghost fishing).
• Ingesting plastic can lead to intestinal blockage or suffocation, especially in larger marine mammals and birds.

Other Dumping Practices

• Includes military discards (e.g., tanks), radioactive waste, and suggests deep-sea dumping for subduction.

Toxins Transport Mechanisms

• Toxins can be carried through air or land systems, affecting water sources.
  • Common sources include PCBs, heavy metals, and agricultural runoff.

Toxic Metals

• Sources include mining, industrial processes, and agricultural activity.
• Health Effects:
  • Mercury: Converts to methylmercury, biomagnifies, disrupts nervous systems (Minamata disease).
  • Cadmium: Bioaccumulates leading to kidney damage; found in marine sediments.
  • Lead: Particularly harmful to children, affecting neural development.
• Mussel Watch Program: Monitors bioavailable toxic metals in the environment.

Pesticides' Effects

• Various pesticides harmful to marine life (e.g., crustaceans).
• DDT: Notorious for slow degradation, leading to reproductive issues in birds (thin eggshells).

PCBs and PAHs

• PCBs: Industrial chemicals, accumulate in marine organisms, carcinogenic.
• PAHs: Derived from fossil fuels, concentrate in sediments, disrupt endocrine systems affecting fish reproduction.

Disease Agents from Sewage

• Harmful microbes (e.g., Salmonella) from sewage can infect marine environments.
• Water quality is gauged by coliform bacteria counts; pathogens concentrate in bivalves, making them unsafe to consume.

Petroleum Pollution

• Sources include agricultural runoff, offshore drilling, oil tanker spills.
• Primary oil types:
  • Aromatic Hydrocarbons: Highly toxic (e.g., benzene).
  • Aliphatic Hydrocarbons: Less toxic (e.g., octane).

Oil Degeneration

• Oil film formation on surfaces; some components evaporate while others are degraded by bacteria.
• Degradation process is faster at warmer temperatures.

Oil Spills and Their Impact

• Deepwater Horizon spill (2010) was the largest, affecting numerous avian species.
• Impacts include:
  • Impaired insulation for birds.
  • Hypothermia risk for otters.
  • Loss of marine invertebrate diversity.

Cleaning Oil Spills

• Strategies:
  • Use of booms and skimmers to contain oil.
  • Bioengineered bacteria for degradation of oil spills.

The Ocean Decade

• Aiming for improved ocean science and sustainability by 2030, addressing major challenges to ocean ecosystems.

Ways to Help the Ocean

• Reduce water use, minimize pollutants, waste reduction practices, sustainable seafood choices, and volunteer for local cleanups to help combat ocean pollution effectively.