Nutrient Pollution (Eutrophication)

• What It Is• What Causes It• What You Can

Do About It

Eutrophication –excess nutrientsWhile nutrients – nitrogen and phosphorus are necessary for life, excessive amounts going into aquatic systems cause major problems

1. One major source is human wastes –from cesspools in rural regions, sewage in urban areas. Especially in older cities with combined sewers, where stormwater is sent to sewage treatment plant. When there is much rain, the water exceeds the capacity of the treatment plant and it all (raw sewage) goes into waterbody untreated

AGRICULTURAL SOURCES• FERTILIZER – EXCESS USE. ONLY 18% OF NITROGEN GOES

INTO CROPS, THE REST RUNS OFF

• MANURE – WHEN EXCEEDS ABILITY OF CROPLANDS TO SEQUESTER, IT RUNS OFF

ATMOSPHERIC SOURCES

• GASES FROM BURNING FOSSIL FUELS RELEASE INTO ATMOSPHERE, THEN THEY ARE DEPOSITED ON LAND AND WATER

URBAN RUNOFF

• Lawn fertilizers and animal waste

• Impervious surfaces - rooftops, sidewalks, roads - covered by asphalt, concrete, brick, and stone - accelerate run-off

• Land use plays major role in water pollution!

HYPOXIA USUALLY MOST SEVERE IN LATE SUMMER/EARLY FALL. 150 “DEAD ZONES” IN WORLD ASSOCIATED WITH NITROGEN FROM FERTILIZERS AND SEWAGE

Nutrients cause algal blooms: (A) When bloom dies, cells sink to the bottom (B) and are decomposed by bacteria which use oxygen. Result is low oxygen (hypoxia) in deeper waters

A

B

PROBLEMS OF EXCESS NUTRIENTS

SOURCES OF

NUTRIENTS

FROM FAR

AWAY

Largest US dead zone is in Gulf of Mexico, which receives nutrient runoff from the main agricultural area of the country. Can be the size of MA or NJ. Size is bigger in years with more rainfall and so more runoff.

Source: Gulfhypoxia.net

Hypoxic Zone-

2014

Source: EPA

Thousands upon thousands of dead and rotting fish float belly-up in the polluted Indian River Lagoon, devastating indictors of the state’s failure to control nutrient levels in one of the mostbio-diverse waterways in the country.

EFFECTS ON CORAL REEFS

• NUTRIENTS CAUSE GROWTH OF MACROALGAE THAT SPREAD OVER AND SMOTHER CORALS.

• EFFECTS WORSE WHEN SEA URCHIN OR FISH HERBIVORES (WHICH WOULD EAT THE ALGAE) ARE SCARCE (PERHAPS OVERFISHED)

CORAL COVERED WITH

MACROALGAE HEALTHY CORAL

• Harmful Algal Blooms (HAB): phytoplankton species that produce toxins affect many different consumers

• Since the 1970s the number of HAB outbreaks has increased 20-fold. Not all related to eutrophication.

• Different species produce different symptoms- all unpleasant

“RED TIDE”

Toxins from bloom can accumulate in shellfish and then poison people who eat them

HABs (often Cyanobacteria) also occur in freshwater, where drinking water sources can be impaired. In freshwater, phosphorus is main cause

SOLUTIONS: Controlling AG Inputs

• CONSERVATION TILLAGE, TERRACING, STRIP CROPPING, CONTOUR CROPPING

• BUFFER STRIPS OF VEGETATION TO CATCH RUNOFF

• REDUCE FERTILIZER USE, RECYCLE MANURE OR REMOVE NUTRIENTS BEFORE DISCHARGE

• REDUCE CONSUMPTION OF HIGH DENSITY FACTORY FARMED BEEF, PIG, AND POULTRY

• RESTORE/CREATE WETLANDS

SOLUTIONS: Urban Management

• IMPROVE SEWER SYSTEMS – INCLUDING COMBINED SEWER OVERFLOW (CSO) PROBLEMS, TERTIARY TREATMENT

• INCREASE WETLANDS FOR TERTIARY TREATMENT

• REDUCE IMPERVIOUS AREAS – MORE GREEN SPACE

• REDUCE EROSION FROM CONSTRUCTION SITES

• STREET SWEEPING

• STORE STORMWATER CSO

Ways to Store Stormwater

Bioswale in Brooklyn

Rain Barrels

Green roof in Chicago

Porous pavement in

parking lots

SOLUTIONS: In-Water Treatment• SEAWEED FARMING:

removes nutrients and might also have a market (agar, sushi)

• GROW OYSTERS AND CLAMS: help control plankton blooms – filter large amount of water daily

• TREATMENT WETLANDS: Plants absorb nutrients, debris trapped in slow-moving waters, microbes break down other pollutants.

Trends and the Future

Eutrophication widespread and increasing in the US and worldwide.

Progress (when seen) due primarily to improvement in point sources (sewage); less for non-point (runoff) sources

HABs increasing world-wide

Recovery time may be very long

Fishing and climate change will intensify the problems

Good news – whales back in NY area

SOLUTIONS: At Home

• CONSIDER YOUR LANDSCAPING

• Add an Ocean Friendly Garden, rain garden, xeriscaping, Florida Friendly Landscaping, or other similar program.

• IMPROVE WATER STORAGE

• Add a rain barrel, swales, and permeable soil to stop runoff.

• GO NATIVE

• Ditch water and fertilizer intensive turf grasses and plant native plants.

WHAT YOU CAN DOMake changes at home- collect rainwater, plant natives

Eat less factory farmed meat, switch to a higher percentage of organically grown plant-based foods

Advocate for upgrading sewage treatment systems- and be sure that your septic tank is working correctly!

Install a gray water system so you can recycle water that goes down the sink

Advocate for strong local fertilizer ordinances and community gray water systems

Help eliminate pet waste - advocate for pet waste disposal stations and make sure local litter ordinances are enforced

RESOURCESQuestions? Contact Dr. Judith Weis at jweis@newark.rutgers.edu

Join the Grassroots Network Sierra Club Marine Team website at https://content.sierraclub.org/grassrootsnetwork/teams/marine-team

Subscribe to the Marine Team List Serve (GRASSROOTS-NETWORK-MAT@lists.sierraclub.org)

RESOURCESCheck out the Sierra Club Water Sentinels program, nationally and locally. Visit their Grassroots Network Water Sentinels Team website at: https://content.sierraclub.org/grassrootsnetwork/teams/national-water-sentinels

As recommended by the Sierra Club Water Sentinels Program, visit the Georgetown Climate Center's Adaptation Clearinghouse for their listing of resources on green infrastructructure. Download their Green Infrastructure Toolkit at: http://www.georgetownclimate.org/adaptation/toolkits/green-infrastructure-toolkit/introduction.html