Compare & Contrast
Food Webs and Food Chains
(hint: page 91 Science textbook)

Write a paragraph comparing and contrasting nekton, plankton, and benthos organisms.
(at least 5 sentences)

Do you know these Properties of Water?
• Polarity – positive or negative charge of a molecule
• Cohesion – water molecules like to stick together
• Surface tension – a force that acts on the particles at the surface of a liquid and causes them to held together tightly
(like skin on the water)
• Adhesion – water likes to stick to other substances
• Solvent – a substance in which another substance dissolves.
• Universal solvent – water dissolves more substances than any other substance
• Density – measure of the mass of a substance per unit volume (how tightly packed it is)
• Buoyancy – ability of a fluid to exert an upward force on an object in (Does it float?)
• Specific heat – amount of energy needed to raise the temperature of 1 kg of a substance by 1° Celsius (The unit is Joule per kg per degree Celsius (J/kg · °C) ) It takes water a long time to heat up or cool down.

• Water (H20) is a simple molecule of two hydrogen (H) molecules and one oxygen (O) molecule bonded together.
• Oxygen has a stronger attraction than hydrogen does, so oxygen has a strong pull towards its nucleus that pulls electrons closer. This gives the water molecule a small negative charge near the oxygen atom and a small positive charge near each hydrogen atom. This gives the water molecule an uneven charge which is called its polarity.
• This causes water molecules to be attracted to each other.
These bonds are called cohesion. They hold water molecules together although they are weak and tend to break easily.
(when something is dropped in the water, it goes in)
• Surface tension is an example of cohesion. It is like a skin at the water’s surface. This allows water spiders to scoot across the surface of the water without falling in.

• Adhesion is the tendency of water to stick to other substances.
• When you add water to a glass, you can see it higher on the sides than it is in the middle. This is because the water is sticking to the side of the glass, making it higher.
• This curved surface (shaped like a U) is called a meniscus.

• Water is a universal solvent since it can dissolve more substances than any other liquid. This is because of its polarity (uneven positive and negative charges of the water molecule).
• Water molecules attract and bond with ions
(negatively charged particles) to make compounds (mixtures).
• This property is why water makes up most of many plants, animals, and other organisms
(including people). The essential nutrients we need dissolve in water and travel to the cells to keep us alive.

• Density is how tightly packed something is. Higher density means it is tightly packed , lower density means it is more loosely packed .
• Density changes with temperature . For example, as you heat water the density decreases because the molecules spread out. This is why colder water is on the bottom of the ocean. Sunlight heats water on the top and causes the molecules to become less dense toward the surface.
• Density changes with physical state . Most substances become more dense as they freeze since the particles become packed together. Water expands (becomes) bigger when it freezes. Ice has a greater volume and lower density than water. Ice floats because it is less dense than water.

 Buoyancy happens because there is an upward force on objects in water causing some of them to float.
 If the upward force (buoyant force) is greater than the downward force (gravitational force), it floats.
 If something is less dense than water, it will float. (Wood, oil, and wax)
 If something is more dense than water, it will sink. (metals)
 Metal boats can float because they are made so they have pockets of air. This air helps to lower the density of the boat enough so it will float.

• The amount of heat it takes to raise the temperature of 1 kg of a substance by 1°
Celsius.
• The unit is joule per kg per degree Celsius (
J/kg · °C )
• The specific heat of water is very high –
4,184 J/kg · ° C
• This means it takes a long time for water to change temperature.
• This high specific heat of water helps to keep your body at a stable temperature. (98.6° F)

Structure of the Hydrosphere
Hydrosphere – the part of the earth that contains water
Salinity – the concentration of salts dissolved in a liquid (How salty is it?)
Glacier – a mass of ice and snow that moves slowly over the
Earth
Groundwater – water located below the Earth’s surface
Aquifer – a rock layer that stores water and allows water to flow through it
Wetland – land areas that remain wet for all or most of the year
Watershed – an area of land where rain collects and drains into one collection place, often a lake or an ocean
River – large, flowing stream of water
Tributaries – smaller streams that drain into a river
Lake – low area of land into which surface water run-off drains

• Water covers about 71% of the Earth’s surface. (The other 30% of the Earth’s surface is dirt.)
• 97% of the Earth’s water is salt water found in the oceans.
• The remaining 3% is fresh water.
• Fresh water is found:
*69% frozen in polar ice caps, glaciers, snow, and permafrost (frozen ground)
*30% liquid water in ground water
*1% in lakes, wetlands, rivers, and the atmosphere

• All of the Earth’s ocean water is connected.
• Continents divide this ocean into 4 parts:
* Pacific Ocean – largest and deepest, deepest part is Marianas trench (11,033 m deep), at the
US west coast
* Atlantic Ocean – second largest, half the volume of the Pacific Ocean, at the US east coast
* Indian Ocean – third largest between Africa,
Australia, and Asia
* Arctic Ocean – smallest and much is covered by ice

• Most of the Earth’s fresh water is frozen in the polar ice caps
• Nearly 1/3 of the Earth’s fresh water is groundwater
• Drinking water often comes from aquifers
• Earth’s surface waters flow through watersheds as they travel to a low area to collect such as lakes or oceans
• Some major lakes of NC are Lake
Mattamuskeet, Lake Phelps, Lake
Waccamaw, and Lake Michie

WHAT IS UP WITH THIS OCEAN THING,
ANYWAY?
OCEAN RESOURCES AND OCEANOGRAPHY
• Natural resources – materials from the environment that are used by living things
• Respiration – oxygen is used to release the energy stored in food (after breathing)
• Photosynthesis – a process by which plants use light energy from the sun to make nutrients in the form of water and carbon dioxide (H20 + CO2)
• Desalinization – a process used to separate salt from seawater
• Oceanography – study of the physical properties of oceans
• Sonar – (SOund NAvigation and Ranging) method of determining the depth of the ocean using echoes

• Plants and people (as well as anything that breathes air) have a special relationship where we help each other survive
• We need oxygen (O2) to breathe and when we breathe out, we exhale carbon dioxide (CO2).
• Plants need carbon dioxide (CO2) for photosynthesis to produce nutrients to survive.
They get rid of oxygen (O2) after photosynthesis.

• In parts of the world where it is hard to get fresh water, people have to get the salt out of the salty ocean water so they have fresh water to drink. This is called desalination .
• Ocean water is boiled. The evaporated water is captured from the air where it is cooled. The salt is left behind.

• SONAR is used to find out how deep the ocean is.
• Sonar equipment on a ship sends a sound down into the water. They see how long it takes for the sound to bounce back from the bottom of the ocean. (The faster the sound comes back, the shallower the water.)
• Since they know how fast sound travels in water, they can tell how deep the water is.
• This helps scientists make maps of the ocean floor.
They can find features such as underwater mountains, canyons, and trenches. They can even track tectonic plate movement.
• Scientists also use (ROV’s) remotely operated vessels to see what is very deep in the ocean. These do not have people on board, but they have cameras and other equipment. This helps them gather more detailed information.

WHERE DO ORGANISMS LIVE IN THE OCEAN?
MARINE ECOSYSTEMS
Benthos – organisms that live on or near the ocean bottom, sometimes attached to surfaces
Plankton – tiny organisms that are moved by ocean currents
Nekton – larger free-swimming organisms that don’t depend on currents to move them around
Intertidal zone – the shoreline area falls between the high tidemark and the low tidemark (gets wet during high tide)
Neritic zone – the ocean area that slopes down from the edge of the shoreline toward the ocean floor
Coral reef – limestone deposit formed from coral shells
Upwelling – the movement of nutrient-rich waters from the deep ocean into shallow areas, brings nutrients that help some kelp forests thrive.
Oceanic zone – made up of the open waters of the ocean (extends from the ocean’s surface to its deepest point)
Hydrothermal vents – cracks in the ocean crust that release mineralrich water that has been heated inside the earth
Estuary – special ecosystem where salty ocean water mixes with fresh water from rivers (salinity changes constantly)

• Organisms that live in the ocean fall into 3 groups. These groups are defined by how they move and where they live in the ocean. Can you describe these groups?
• Group 1 – Benthos
• Group 2 – Plankton
• Group 3 – Nekton

OCEAN LIFE
BENTHOS PLANKTON NEKTON
Plants and animals that live in, on or near the bottom
Examples: kelp, fungi, snails, clams
Small and microscopic organisms that move with the currents.
Examples: krill, algae, jellyfish,
Fish eggs
Larger swimming animals that don’t need the currents to move around
Examples: fish, whales, snakes, eels, shrimp, octupus

OCEAN LIFE ZONES
DETERMINED BY
WATER DEPTH
AND DISTANCE
FROM
SHORELINE
ZONES DIFFER
BY DEPTH,
TEMPERATURE,
PRESSURE,
AND AMOUNT OF
SUNLIGHT
INTERTIDAL
ZONE
NERITIC ZONE OCEANIC ZONE
FALLS BETWEEN
LOW TIDE AND
HIGH TIDE LINE
ORGANISMS
ADAPTED TO LIVING
ON THE SHORELINE
AND HAVE ADAPTATIONS
THAT PREVENT
THEM FROM
BEING WASHED
AWAY
SHORELINE TO
ABOUT 200
METERS
HOME TO A WIDE
VARIETY OF
ORGANISMS
BECAUSE
TEMPERATURE AND
SALINITY ARE
CONSTANT
TWO MAJOR
ECOSYSTEMS ARE
CORAL REEFS AND
KELP FORESTS
INCLUDES THE
DEEP OCEAN
FROM THE SURFACE
DOWN.
THE FLOOR IS
CALLED THE
ABYSS. IT IS
COLD, DARK,
AND HAS
HIGH
PRESSURE
BENTHIC ZONE

I HOPE I AM AT THE TOP OF THE FOOD CHAIN!!
FOOD WEBS: LAND AND WATER
Producer – an organism that makes its own food
Consumer – an organism that eats other organisms
Decomposer – an organism that breaks down and eats dead organisms
Trophic level – each feeding level (example: producer, primary consumer, secondary consumer, decomposer) in an ecosystem
Food chain – the flow of energy from one organism to another in an ecosystem
Food web – this shows the connected network
(web) of food chains within an ecosystem
Energy pyramid – the flow of energy in an ecosystem that shows how energy available to consumers decreases as the trophic levels increase.
(Coach, p. 155)

CONNECTIONS BETWEEN LAND AND WATER
Terrestrial food webs show feeding relationships in a land ecosystem.
Aquatic food webs show feeding relationships in a water ecosystem.
For example, if an insect emerges from a stream and is eaten by a bird, energy is transferred from the stream ecosystem to the land ecosystem. P. 154
Grizzly bears eat fish, etc. Can you think of any more?

HOW CAN I TELL IF THIS WATER IS CLEAN?
EVALUATING WATER SYSTEM HEALTH pH – the measurement of how acidic or basic water is
Turbidity – how clear water is (high turbidity means unclear water, low turbidity means clear water)
Algal bloom – rapid growth of algae caused by too many nutrients in the water (also causes high turbidity)
Nitrates – nitrogen compounds used for growth by plants and algae (fertilizer)
Bio-indicators – organisms or parts of organisms that are used to check the health of an ecosystem

• A HEALTHY WATER SYSTEM HAS
MODERATE TO COOL
TEMPERATURES, HIGH DISSOLVED
OXYGEN, LOW ACIDITY (pH), AND
CLEAR WATER (LOW TURBIDITY)
• COOLER WATER HOLDS MORE
OXYGEN
• CHARTS ON PAGES 159 AND 160

TECHNOLOGY AND THE HYDROSPHERE
Remote sensing – scientists use satellites to monitor all areas of the earth (p. 162)
Global positioning system (GPS) – use of satellites to pinpoint locations on the earth
Geographic information system (GIS) – mapmaking software that creates different map layers for the same area (Each layer tells something different about the area – location of watershed, for example)

HOW HUMANS AFFECT WATER
Pollutant – any substance or form of energy that can cause harm to the environment
Point-source pollution – if you can point to the source of the pollution (there is proof of only one source of pollution)
Non-point-source pollution – pollution that comes from many similar places or a source that is not easily identified (you can’t pinpoint one specific source of pollution)

PROTECTING WATER RESOURCES
Wastewater – water that runs into city drains
Wastewater treatment plants – a facility that processes water to remove wastes and then releases the clean water into a lake or stream
Septic system – a wastewater treatment system for an individual home or farm
Drain field – a series of pipes with small holes that are buried under rocks that help to filter the wastewater from a home to make it clean. Small microorganisms also help clean the water so it can go into the ground and be used again.