Freshwater ecosystems “We will never be able to feed the hungry or meet the needs of the billion people that lack access to clean water unless we can sustain the benefits and services that freshwater ecosystems are providing to society free of charge.” Brian Richter, co-lead for the Conservancy’s Global Freshwater Team

Freshwater Ecosystems 3% of world’s water is fresh. 99% of this either frozen in glaciers and pack ice or is buried in aquifers. The remainder is found in: Lakes, ponds, rivers, and streams

Lakes and Ponds Three Distinct Zones: Littoral Zone – close to shore, light reaches bottom Producers include: plants and algae Consumers include: tiny crustaceans, flatworms, insect larvae, snails, frogs, fish and turtles Limnetic Zone – layer of open water, photosynthesis occurs, more prominent in lakes Producers include: planktonic algae Consumers include: swimming insects and fish and microscopic crustaceans

Lakes and Ponds Draw this in your Notes! Profundal Zone – many lakes (but few ponds), not enough light to support productivity Primary consumers are either attached to or crawl along the sediments (Benthos) Sediments support bacteria and fungi Draw this in your Notes!

Freshwater ecosystem Draw this in your Notes! Draw this in your Notes!

Fall Overturn Change of seasons: Warming of surface water prevents water from mixing with deeper water. (Warm water is less dense than cold.) Surface water is oxygen rich. Air above it Photosynthesis Water in profundal zone is stagnant. In the fall, Surface water cools, becomes denser and sinks to bottom, carrying oxygen with it

Fall Overturn

Rivers and streams Current makes the water more oxygenated Photosynthesizers play a minor role in the food chains Large fraction of the energy for consumers is from land (ex. Falling leaves)

The Role of freshwater ecosystems (Essential to Human life) Freshwater ecosystems are a critically important source of food. 15% of the fish we consume comes from freshwater habitats Freshwater ecosystems: Store flood waters Purify water supplies Generate electricity with hydropower Produce building materials such as timber and clay bricks Deliver sand to replenish coastal beaches

Threats to freshwater ecosystems Freshwater ecosystems have lost a greater proportion of their species and habitat than those on land or in the oceans. Primary Threats: Dams Water pollution Invasive exotic species Direct habitat destruction Overharvesting of plants and animals Global climate change

STORMS

Tropical Cyclones/Hurricanes Storm system Characterized by: low pressure center thunderstorms strong wind flooding rain Feed on heat released when moist air rises (water vapor releases heat as it rises, cools, condenses)

Storm usually doesn’t last for more than 7-10 days. What Is a Hurricane? Description: A hurricane can best be described as a huge tropical storm (up to 600 miles in diameter)! Winds can be up to 200 mph! Storm usually doesn’t last for more than 7-10 days. It moves across the ocean at around 10-20 mph…not too fast really! Arrows indicate “feeder bands” or “rain bands” The winds are the strongest around the eye wall. The eye of the storm is usually about 20 miles in diameter. Within the eye, winds are calm and the weather is great. Strongest winds are on the right side, heaviest rain is usually on the left side.

Factors necessary for tropical cyclone formation: Water Temperature At least 26.5 °C to depth of 50 m Rapid Cooling with Heating Allows release of heat of condensation High Humidity Continued next slide…..

Distance Away from Equator Low Wind Shear High shear is disruptive to the storm’s circulation Distance Away from Equator More that 500 km or 5 degrees of latitude Allows Coriolis effect to deflect winds Pre-existing System of Disturbed Weather

Storm Classification

Tropical Depression Organized system of clouds and thunderstorms Maximum sustained winds <38 mph

Tropical Storm Maximum sustained winds increase to between 39-73 mph

Hurricane System with sustained winds of >74 mph Hurricance Classification Category 1: 74-95 mph Category 2: 96-110 mph Category 3: 111-129 mph Category 4: 130-156 mph Category 5: 157 mph or higher

Wind Simulator

Saffir-Simpson Scale of Hurricane Intensity

Hurricane Naming System – Why do they have names anyway? 2015 Hurricane Names Ana Bill Claudette Danny Erika Fred Grace Henri Ida Joaquin Kate Larry Mindy Nicholas Odette Peter Rose Sam Teresa Victor Wanda In 1953 the National Weather Service began naming storms after women. In 1979, men’s names were added to the list of hurricane names. In the Atlantic, there are 6 lists of names that are recycled. In the case of storms so devastating that reusing the name is inappropriate, the name is taken off the list and another name is used to replace it. The name “Katrina” is one that has been removed from the listlist. Next year’s list

Eye and Inner Core Sinking air at the center If winds strong enough eye will form Heaviest wind damage occurs at eye wall

Landfall Storm’s center crosses coastline Coastal areas will “feel” it coming hours before landfall

Coastal Effects Can produce powerful winds and torrential rain Can produce high waves and damaging storm surge

Inland Effects Damage to vehicles, building, bridges, etc. Possible flying projectiles. Heavy rains can produce significant flooding and storm surges can produce extensive coastal flooding up to 25 miles from the coast line. Historically resulting in 90% of cyclone deaths In the last two centuries, tropical cyclones have been responsible for 1.9 million deaths

Hurricane Season Our Season- June 1 to November 30

Dissipation occurs when: Moves over land, depriving itself of warm-water. Remains in the same area of ocean too long mixing the upper 30 meters of water (water becomes too cool). Moves into water < 26.5 °C

Long Term Trends More intense hurricanes are expected over next century due to global climate change – the earth’s warming due to increasing levels of greenhouse gases in the atmosphere.

Helpful Hurricanes? Relieve drought conditions. Help maintain equilibrium in Earth’s atmosphere and maintain relatively stable and warm temperature worldwide.

http://www.youtube.com/watch?v=zP4rgvu4xDEHurricane!

More cool stuff to check out…

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The Path of Hurricane Katrina

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El Nino El Niño is a long period of warming in the Pacific Ocean sea surface temperatures when compared with the average temperatures. This is a warming of at least 0.5°C (0.9°F) averaged over the east-central tropical Pacific Ocean. Typically, this anomaly happens at irregular intervals of two to seven years, and lasts nine months to two years. The average period length is five years.

El Nino Continued The first signs of an El Niño are: Rise in surface pressure over the Indian Ocean, Indonesia, and Australia Fall in air pressure over Tahiti and the rest of the central and eastern Pacific Ocean Trade winds in the south Pacific weaken or head east Warm air rises near Peru, causing rain in the northern Peruvian deserts Warm water spreads from the west Pacific and the Indian Ocean to the east Pacific. It takes the rain with it, causing extensive drought in the western Pacific and rainfall in the normally dry eastern Pacific.