Name

 

March 25, 2003

                                                                                                                                      

Oceanography Test

Define the Following Terms (35 points) Use 12 point Times New Roman Font and Type your answers in the table provided.

 

Eutrophication

A process that occurs as a result of an excessive flow of nutrients into an aquatic environment. The nutrients result in a Bacterial or Algal population explosion called a bloom. These simple organisms out compete and kill off more complex plants causing the normal food chain to collapse

Chemosynthesis

A type of autotrophism in which bacteria use chemical bond energy to make food

Upwelling

A process in which nutrient rich bottom currents are brought up to the surface of the ocean

Vertical Migration

A process in which organisms the dwell in the Aphotic Zone come to the surface at night to feed.

Estuary

The mouth of a river or stream where nutrient rich fresh water mixes with the ocean. These areas are important for supporting shellfish fisheries and act as nurseries for young fish.

El. Niño

A weather pattern that occurs occasionally over the pacific that disrupts normal weather patterns.

Algal Bloom

A population explosion of simple algae

 

Short Answer

 

Question #1 (11 points)

Compare the two different kinds of upwelling that we discussed in class. What causes each. (6 points) Why would the kind of upwelling seen in Peru be less consistent than that found at Georges Bank. (3 points) What happens to a fishery if upwelling stops? (2 points)

 

Answer #1

One kind upwelling occurs when an undersea obstruction like a mountain deflects nutrient rich bottom currents to the surface. (Georges Bank)

The second kind of upwelling occurs when prevailing wind pushes surface water off shore. This causes bottom water to flow up bringing nutrients to the surface. (The Coast of Peru) This kind of upwelling requires wind. Winds are not as dependable as currents. Every few years an El. Nino occurs in the Pacific. This disrupts normal wind flow. Upwelling stops and no nutrients are brought to the surface. The phytoplankton fail to reproduce. This starts a chain reaction up the food chain destroying the fishery.

 

Question #2 (13 points)

Give a short definition of the term, “productivity”. (5 points) Name two different factors that effect productivity (4 points) Explain how each of these factors can limit productivity. (4 points)

Answer #2

Productivity refers to the amount of food produced in an ecosystem. It is usually measured in Biomass. Both sunlight, and the amount of nutrients present effect productivity. If there is a lack of sunlight in an area  either because of climate, or the depth of the water that area is not likely to be very productive. (for example the deep ocean) Nutrient rich areas like Cape Cod are likely to be more productive than nutrient poor areas like the Caribbean..

 

Question #3 (6 points)

Why are Estuaries important? (3 points)  Why are they susceptible to Eutrophication (3 points)

Answer #3

Estuaries are the areas where the Rivers and Streams meet the sea. They are very productive and support large shellfish fisheries as well as acting as nurseries for young fish. They are susceptible to Eutrophication because they are fed by rivers. Human activity and development along rivers can dramatically increase the nutrient load of the river increasing the chance of Eutrophication.

 

Question #4 (6 points)

The consequences and causes of an algal bloom compared to the consequences and causes of a bacterial bloom.

Algal blooms are caused by excessive inorganic nutrients like Nitrates and Phosphates. Algal blooms cloud the water and damage the ecosystem by preventing light from reaching other bottom dwelling plants. This kills those plants and any organisms that depend on them for food.

Bacterial blooms are caused by organic compounds like sewage. Bacteria damage the ecosystem be using up all the oxygen and killing off higher organisms.

 

 

 

 

 

Question #5 (20 points)

Shown here are 4 different organisms. In the area provided tell where they live and explain the source of energy that provides the basis for their ecosystem. Do these organisms make their own food or do they eat other creatures.  How have these organisms adapted to make use of the food in their ecosystem.

 

 

 

 

These organisms live at the ocean floor. The energy that supports come from the inorganic high energy chemicals  that pore out of the hydrothermal vents. They have chemosynthetic bacteria living in their tissues that manufacture their food. They provide a place for chemosynthetic bacteria to live

Tube worm near a hydrothermal vent

 

These organisms live in the Aphotic Zone yet there energy comes from the sun through photosynthesis. These organisms migrate to the surface every night to eat the phyto and zoo plankton at the surface. They have adapted this life style to take advantage of the food sources at the surface while still enjoying the safety of the deep water.

Vertical Migrating Lanternfish

 

Kelp live attaches to the bottom in th euphotic zone. The use sunlight to manufacture their own food. They have highly specialized tissues that allow the to remain attached to the bottom and have blades that capture the light.

Kelp

 

These fish live in the aphotic zone. They depend sun for energy because they scavenge dead organisms that drop from the surface. They have small eyes and gigantic mouths to catch falling prey

Deep Sea Gulper Fish

 

 

 

 

 

 

 

Differentiate between 12 points

Benthic and Pelagic

Bottom dwelling vs open water dwelling

Chemosynthesis and Photosynthesis

Using  Chemicals to make foor vs using light energy to make food

Phytoplankton and Zooplankton

Small algae that drift in the ocean vz the small animals that drift in the ocean and feed on them

Phytoplankton and Macro Algae

Phytoplankton and small usually unicellular algae. Macro algae are multicellular and generally more complex.