Emissions from a smokestack of a factory 🏭 or coal power plant (CO₂, NO₂, SO₂, PM)
Animal waste runoff 💩 from a CAFO (ammonia (N), fecal coliform bacteria)
BP Oil Spill🛢(hydrocarbons, benzene)
Untreated sewage coming out of a pipe into a river 💩
Vehicle exhaust coming out of a car tailpipe 🚗

✅ Easier to identify

✅ Easier to regulate

Non-point Source: Pollutants that do not have a definitive source (or result from a combination of many sources)

Non-point source pollution transported by water, or going into water 🌊, is commonly referred to as “runoff”.

Urban runoff 🏙 (motor oil, nitrate fertilizer, road salt, sediment)
Pesticides sprayed on agricultural fields; carried by wind 🌬 and washed off large agricultural regions into bodies of water
Excess fertilizer washing off all the lawns in a neighborhood during a rain storm 🌧 into a local creek
Smoke from a wildfire 🔥

Estuaries and bays are polluted by many non-point pollution sources from the large watersheds that empty into them.

Non-point sources of pollution in a watershed:

Natural 🌲
Industrial 🏭
Urban 🏙
Agricultural 🐮 (the largest source of water pollution!)
Residential 🏘

❎ Difficult to identify

❎ Difficult to regulate

Q: Look at the images of a smokestack (left) and water runoff (right). Can you identify which one is a point source and which one is a non-point source?

A: Although they both appear to be coming from a singular source, only the smokestack is a point source because it is coming from one identifiable factory. The water runoff, however, is a collection of all the potential pollutants found on the street. If something toxic was found in that water, it would be very difficult to track down and regulate the source.

8.2 Human Impacts on Ecosystems

Organisms have a range of tolerance for abiotic conditions in their habitat.

pH
Temperature 🌡
Salinity 🧂
Sunlight ☀
Nutrient levels (ammonia, phosphate)

Organisms also have a range of tolerance for various pollutants that human activities release.

Outside of this range, organisms may experience physiological stress:

Limited growth ⏫
Limited reproductive function 🐣
Difficulty respiring (breathing) 🫁, potentially asphyxiation (suffocation)
Hormonal disruption 👤
Death ☠ (if pollutant concentration is high enough)

Environmental Effects of Acidic Rain 🌧

pH Tolerance

As pH decreases (more acidic) outside the optimal range for an aquatic species, they cannot survive due to:
- Aluminum toxicity
- Disrupted blood osmolarity (imbalance of Na⁺/Cl^- at low pH)
Indicator Species: an organism whose presence, absence or abundance reflects a specific environmental condition
- Can be surveyed and used to determine conditions of an ecosystem (soil, water, etc.)
  - Ex: whitemoss/filamentous algae 🦠
    - High Population ⬆ = pH < 6.0
  - Ex: crustaceans 🦀
    - High Population ⬆ = pH > 6.0

Temperature Tolerance of Coral Reef 🪸

Coral reef have a mutualistic relationship w/ photosynthetic algae called zooxanthallae

Algae supply sugar
Coral supply CO₂+ detritus (nutrient containing organic matter)

Human Impacts on Coral Reef

Humans disrupt coral reef ecosystems via:

Greenhouse gas emissions, which warm ocean temperatures and bleach coral
Overfishing 🎣, which decreases fish populations → overgrowth of algae
Bottom-trawling 🥅, which can break reef structure and stir up the sediment

Urban and agricultural runoff also damages coral reef ecosystems:

Sediment Pollution: sediment carried into the ocean by runoff makes coral reef waters more turbid, reducing sunlight ☀ for photosynthesis
Toxicants: chemicals in sunscreen, oil from roadways, pesticides from farm runoff
Nutrients (N/P): ammonia from animal waste 💩, nitrates/phosphates from agriculture or lawn fertilizers

Oil Spill Effects 🛢

Hydrocarbons in crude oil (petroleum) are toxic to many organisms and can kill ☠ them, especially if they ingest the oil or absorb through gills/skin.

Other physiological effects:

Oil that floats on the surface of water can coat the feathers 🪶 of birds and the fur of marine animals, drowning them or impeding their everyday survival
- Oil mats and separates birds’ feathers, impairing waterproofing and insulating abilities
Decreased visibility → Decreased photosynthesis due to less ☀ penetrating the water surface
Oil that sinks to the ocean floor can ruin habitats and kill bottom-dwellers due to direct toxicity or suffocation

Oil that washes up on the beach can have economic 💸 consequences on the fishing 🐟kills fish) and tourism 🧳 (deters tourists from visiting) industries.

Oil can settle deep in root structures of estuary habitats like mangroves or salt marshes.

Can be toxic to salt marsh grasses, killing them and loosening their root structure, leading to coastline erosion
- Can remove habitats used by fish 🐟 & shellfish 🦐 for breeding grounds

Oil Spill Clean-Up 🧽

Oil spills can occur when an underwater oil well explodes/blows out 💣 or when a tanker runs into a rock/iceberg and is punctured.

Clean up can involve:

Booms on surface to contain the spread of oil and ships with vacuum tubes to siphon oil off of the surface or devices to skim it off
Physical removal of oil from beach, sand, and rocks with towels, soaps, shovels
Chemical dispersants sprayed on oil slicks to break up and sink to the bottom
- Clears up surface, but can smother bottom-dwellers
- Dispersant chemicals may be harmful
Burning oil off surface
- Releases harmful pollutants and greenhouse gases ⚠

8.4 Human Impacts on Wetlands and Mangroves

Wetlands

An area submerged with soil submerged/saturated in water 💧 for at least part of the year, but shallow enough for emergent plants

wetland plants (cattails, lily pads, reeds, etc.) have adapted to living with roots submerged in standing water

Mangroves

Coastal ecosystems characterized by salt-tolerant trees and shrubs that grow in intertidal zones along tropical and subtropical coastlines.

Related to estuaries (an area where water from the sea meets and mixes into freshwater)
Differences in salinity🧂make it difficult for most plants to grow, but mangroves are an exception!
Mangrove trees have adapted to the high salinity levels of estuaries
- Ecosystem services: water filtration, are a valuable source of timber 🪵 and fuel, protect inland areas from damage, reduce the impact from floods, provide nursery habitats for various marine species, and store large amounts of CO₂
Face significant threats from anthropogenic activities like deforestation for agricultural and urban development, leading to habitat loss and decreased biodiversity

Ecosystem Services of Wetlands

🦀🐟 Provisioning: habitat for animal & plant foods
- Amphibians like frogs and salamanders can live in wet places like wetlands
🌡 Regulating: groundwater recharge, absorb. of floodwater, CO₂ sequestration
- Wetlands are meant to hold water, so when huge amounts of water runoff, the wetlands can absorb all of it
- Wetlands also actively trap greenhouse gases, reducing strain on the atmosphere
🚰🐝🕷 Supporting: H₂O filtration, pollinator habitats, nutrient cycling, pest control
- Wetlands filter runoff, such as agricultural pesticide, before it reaches larger bodies of water. Plants use the nutrients wetlands trap.
🏕🛶👩‍🔬 Cultural: tourism revenue, fishing license, camping fees, ed/med research

Threats to Wetlands

Pollutants: nutrients (N/P), sediment, motor oil, pesticides, endocrine disruptors
Development: wetlands can be filled in or drained for urban development (homes, parking lots, stores, etc.)
Dam construction: dams divert water flow, preventing water from reaching wetlands. Since they cannot refill, they inevitably drain
🎣 Overfishing: disrupts food web of wetlands (decrease in fish predators, increase in prey)