Water, Water Everywhere!• If you poured all the world’s water on the United States and

could contain it, you’d create a lake 90 miles deep. • How much water is that? Roughly 326 million cubic miles,

according to the U.S. Geological Survey. Some 72 percent of Earth is covered in water, but 97 percent of that is salty and no good for drinking.

So, some facts about the freshwater: • 70 percent of freshwater is locked in ice caps • Less than 1 percent of the world’s freshwater is readily

accessible • 6 countries (Brazil, Russia, Canada, Indonesia, China and

Colombia) have 50 percent of the freshwater reserves • One-third of the world’s population lives in “water-stressed”

countries

AQUATIC LIFE ZONES

Section 5-2

Aquatic “Biomes” are determined by the salinity of the water

Saltwater/Marine1. open sea2. estuary3. coast line4. coral reef5. coastal marsh6. mangrove swamp7. coastal wetlands

Freshwater1. Lakes & Ponds2. Flowing Streams3. Inland wetlands

AQUATIC LIFE ZONES

Living in WaterADVANTAGES

• Buoyancy for support• Limited fluctuations in

temperature• Nutrients are dissolved and

easily available• Wastes are diluted &

dispersed

LIMITING FACTORS• Temperature• Sunlight• Dissolved Oxygen• Nutrients

• These divide ALZ’s into layers:

• Surface,• Middle• Bottom• Different Organisms will live

different places!

I. MARINE ZONES• The Ocean is divided into COASTAL zone & OPEN sea

A. COASTAL ZONE – general information- warm, nutrient rich- land to continental shelf- covered at high tide, exposed at low tide- 10% of ocean area but 90% of species- connect with estuaries- protect land

COASTAL ZONES – specific types1. ESTUARIES

- where fresh & salt water meet- streams flow into ocean

- lots of nutrients available- good breeding ground for organisms

2. COASTAL WETLAND- areas of coastal land covered for part or all of the year with salt water- bays, lagoons, salt flats, mud flats, salt marsh

COASTAL ZONE specifics

3. MANGROVE SWAMPS- warm tropical coasts with an over-abundance of silt (sediment & nutrients)- 55 species of salt-tolerant trees & shrubs- prevent coastal erosion; roots above water

4. SHORES- can be rocky or sandy (barrier)

5. CORAL REEF• Found in shallow coastal zones of warm

tropical & sub-tropical oceans• Underwater populations of polyps (animals

similar to jellyfish) that secrete limestone shells

• Most productive ALZ

B. OPEN SEA• Divided into 3 zones, depending on the

amount of sunlight EUPHOTICBATHYALABYSSAL

• Very low avg. net primary productivity – (phytoplankton mostly)– 10% of ocean’s species

• Large gross primary productivity however– Simply because of total size

II. FRESHWATER ALZ’SA. FRESHWATER LAKES – general information• Large, natural bodies of standing (still) freshwater• Formed from ppt, runoff or groundwater that fills

depressions in Earth’s surface• Tend to have a lot of algal growth

– No current to carry away or disperse

• Temp. is often high• 3 types of lakes; 4 zones within a lake

3 TYPES OF LAKES1. OLIGOTROPHIC LAKE (poorly nourished)• Newly formed• Very deep with steep banks• Gravel, sandy, rocky bottoms• Little shore vegetation, not much algae• Crystal-blue or green in color• Small pop.s of pp and small fish (trout & bass)

3 TYPES OF LAKES2. EUTROPHIC LAKE (well-nourished)• Aged lake• Excessive nutrients, rapid decomposition• Shallow, murky water from algae growth• Sunlight can’t penetrate far, not many fish at

the bottom• Much vegetation

3 TYPES OF LAKES3. MESOTROPHIC LAKES--In between Oligo & Eu - trophic

Lakes are divided into 4 Zones

4 LAKE ZONES1. LITTORAL ZONE• Shorelines & very shallow waters around

edges.• Most vegetation grows here2. LIMNETIC ZONE• Top layer of water• Most organisms found here• Highest temperature; sun easily penetrates

4 ZONES IN LAKE3. PROFUNDAL ZONE• Below the limnetic zone• Less sunlight & nutrients• Not many organisms found here4. BENTHIC ZONE• Very bottom layer of water, including bottom

sediments• Little, to no, organisms live there• No sunlight penetrates

Lake Stratification – Seasons change temperature

B. FRESHWATER STREAMS• Running water with currents• Generally cold temps• Usually clear, algae is quickly carried away• Forms from surface water or runoff that does

not soak into ground• 3 zones

Freshwater Stream Zones1. First (narrow) Zone• Headwaters/mountain highland streams• Beginning of the stream• Water is very cold• Many waterfalls/rapids• Large amount of dissolved oxygen• Cold water fish (trout)• Algae & moss attach to rocks

Freshwater Stream Zones

2. Second Zone• 1st zone meets with other streams• Slower current, warmer water• Less obstacles (rocks, etc.)• Mix of warm & cold water fish

Freshwater Stream Zones3. Third Zone• Streams join together to form a river• Wide & murky• High temperatures• Low dissolved oxygen content• Lots of sediment that deposits at end• Carp & catfish

C. Inland Wetlands• Lands covered with water all or part of the

year (excluding streams, lakes, resevoirs)• Examples include:

1. marshes (herbaceous plants)2. prairie potholes (seasonal)3. swamps (tress & shrubs)4. mudflats5. bogs