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.