Chapter 3 Flashcards
What role do streams play in the water cycle?
They affect and ARE affected by precipitation, groundwater, evaporation, etc.
What is the water cycle?
A movement between sinks and fluxs
What is a reservoir/sink? List them (6)
Where water is typically held for an extended period of time.
Ocean
Groundwater
Polar Ice/Glaciers
Atmosphere
Soil moisture
Lakes
What is a flux? List them (6)
Movement of water from one reservoir to another.
Precipitation
Evaporation
Evapotranspiration
Vapor transport (aka clouds)
Precipitation
Rivers
Why is a river a flux and not a sink?
Because a river is taking water from one sink to another.
Why is water polar?
Due to the electronegativity of oxygen pulling unevenly on the less electronegative hydrogen, resulting in areas of positive/negative.
How many protons & electrons does oxygen have?
8 protons, 8 electrons. 6 of the 8 electrons are valence electrons
How many protons & electrons does hydrogen have?
1 proton, 1 electron
What is the relative strength of a hydrogen bond? (compared to other IMFs and covalent/ionic bonds)
A hydrogen bond is relatively weak. Stronger than most IMFs. However, many hydrogen bonds together are very strong.
List the 5 most important properties of water
High specific heat
Cohesion
Viscosity
Buoyancy
Pressure
How does high specific heat affect aquatic life?
Buffers water temperature for cold-blooded aquatic animals
What is specific heat? What does high specific heat mean in terms of water?
How many calories does it take to raise 1g of X substance by 1C?
It takes 1 cal to raise 1g of water by 1C. This means water can store large amounts of heat energy with only a small increase in temperature
Why is water special in terms of changing states of matter?
Changing states of matter requires large amounts of heat energy due to high specific heat.
only 1cal reduces 1g of water by 1C, HOWEVER, if you wish to hit 0C, you must put 80cal of energy in to reduce 1g of water by 1C to 0C and turn it into ice.
Why does ice float?
A lattice is formed by hydrogen bonding, so they spread out further when they turn to ice. THis causes ice molecules to be less dense than liquid.
At what temperature is water most dense?
4C
What is cohesion? What does it produce?
Water molecules on the surface bond more strongly to water molecules below. Produces surface tension
What is surface tension?
Surface of water is “tight” and creates a barrier to small organisms (this also allows other organisms to walk on water!)
What is viscosity? What is the difference between water and air?
Force required for an object to move through liquid. Water has a frictional resistance 100x greater than air
How does viscosity affect aquatic life?
Aquatic vertebrates tend to have a streamlined/torpedo shape to reduce frictional resistance.
May also be super skinny and tall/long (look like a piece of paper)
What is buoyancy?
Upward force exerted when a body in water weighs less than the water it displaces. Reduces the effect of gravity.
How does buoyancy affect aquatic life?
Organisms need less structural support in water than on land, allowing them to be very large.
*This is due to water density being ~860x greater than air, so an animal must weigh MUCH more for it to weigh more than the water it displaces.
How does pressure affect aquatic life?
An organisms body must be much more capable of handling pressure the deeper in depth that it lives in.
*1000atms of pressure in water is 15,000lbs per square inch, whereas 1000atms of pressure on the surface is 14.7 lbs per square inch.
What is a reflection (related to when light strikes water)
When light reflects off surface.
How does reflection amount change daily and seasonally?
The lower the angle at which the rays strike the surface, the more light that is reflected (daily)
Seasons affect daylight length, as well as the angle in which the sun is at
What is transmission as its related to light striking water?
Transmission is the absorption of light. Suspended particles and organisms either absorb or scatter the light, and help water to absorb.
Is light absorbed equally?
NO. Different wavelengths are absorbed differently.
As related to transmission, what happens when there is less “stuff” in bodies of water?
You can see further into a body of water, and light can transmit further down.
Why does light transmit differently? What wavelength transmits the furthest? the shortest?
Due to longer wavelengths = less energy.
Red transmits the shortest as it has the longest wavelength and therefore the least amount of energy
Blue transmits the longest as it has the shortest wavelength & highest amount of energy.
Why does prime photosynthesis occur at the top of a body of water?
Due to majority of wavelengths being absorbed at top, allowing for highest amount of photosynthesis.
How is heat distributed in water? How does it reach depths relatively further from the surface?
Distributed vertically. Wind and waves mix surface waters around, and this mixture extends beyond where solar radiation can reach. This “churning” of surface waters allows heat to reach further than solar radiation.
Thermocline
Zone of rapid temperature change.
Epilimnion
Upper layer of warm, less dense water. Surface water.
Hypolimnion
Lower layer of cold, more dense water. Deep water. Temperature continues to decline here with depth but at a slower rate than thermocline.
What do seasonal changes in solar radiation do to the zones of surface water?
In the tropics - no large changes. all 3 layers continue to exist.
In the temperate zone - in fall/winter, thermocline is not present.
Describe the 4 seasons of a temperate zone and how these seasons affect the 3 zones of water.
Summer: Thermocline is present and surface water is warmest
Fall: Surface water begins to cool. Cooler water sinks, allowing warmer water to surface. This repeats until temperature becomes uniform throughout water (thermocline disappears) TURNOVER OCCURS
Winter: Surface water cools further and ice may form on surface
Spring: Surface water begins to warm. Causes temperature to become less uniform, results in a LARGE turnover
Turnover
Vertical mixing causing movement of nutrients. Physical “churning” of the 2 layers
How does water temperature affect oxygen solubility?
Colder water increases oxygen solubility.
HOWEVER - ice formation greatly reduces diffusion of oxygen into surface waters.
What does a decline in oxygen solubility reflect?
Reflects the demand and uptake of decomposer organisms inhabiting the bottom zone.
Decomposers use a lot of oxygen to break down organisms, so there is a reduced amount of oxygen in the water towards the bottom.
Aquatic organisms generally require less structural support due to water’s high ______
buoyancy
How does an increased atmospheric CO2 concentration result in increased ocean acidity?
CO2 reacts with water to form H2CO3
Molecules spontaneously move from areas of higher concentration to an area of lower concentration in a process known as ______
diffusion.
The depth of a thermocline is directly influenced by wind speed, wave action, and input of solar radiation, but not _______________
the influx of water
The purest form of water containing the fewest solutes occurs in
Clouds
you are scuba diving in deep water and accidentally cut yourself. This blood appears blue. Why?
Red light has been filtered out at this depth.
