A.   An area of hypoxia or where there is too little oxygen in the water causing organisms to die

B.   A burial ground for dead animals no longer useful on a farm

C.   An area where all the fish have been caught

A.   20,000 square kilometers

B.   40,000 square kilometers

C.   1,000 square kilometers

D.   100,000 square kilometers

E.   10,000 square kilometers

A.   A drop in the salinity of the ocean.

B.   The over enrichment of the sea by nutrients that allow plants to grow.

C.   The spill of chemicals that block plant growth.

D.   A rapid rise in the pH of water.

A.   Rising fossil fuel use, bykill, and the construction of sewage systems drive excess nitrogen into coastal waters.

B.   Rising fossil fuel use, mass breeding of food animals and intensive farming, and bykill.

C.   Rising fossil fuel use, mass breeding of food animals and intensive farming, and the construction of sewage systems drive excess nitrogen into coastal waters.

D.   Nuclear energy use, mass breeding of food animals and intensive farming, and the construction of sewage systems drive excess nitrogen into coastal waters.

E.   Overfishing, bykill, and thermo luminescience.

A.   No

B.   Not yet but models predict it will be in 50-100 years

C.   Yes

A.   Its causing the diatoms to outnumbered other ocean creatures

B.   Diatoms are toxic and they destroy all food webs

C.   Gelatinous organisms eat all the diatoms

D.   This is a problem because diatoms become outnumbered by small or less digestible types of species and gelatinous organism reduce the efficiency of the food chain causing fish stocks to drop.

A.   An imbalance of the food chain worsened by immense fishing. The hunting of a top predator results in rising numbers of zooplankton and less phytoplankton.

B.   It occurs when plankton die and thus all who need them die

C.   It occurs when fishing vessels catch all members of one species and then catch all members of another.

D.   An imbalance of the food chain worsened by immense fishing. The hunting of a top predator results in rising numbers of smaller fish eating more zooplankton and leading to more phytoplankton.

A.   7 days

B.   20 days

C.   Its entire life

D.   40 days

E.   3 days

A.   Dead zones can be restored by reducing the nutrient delivery from nearby lands

B.   Nothing can be done to restore the area

C.   Dead zones can be restored by adding nutrients from the land to the water.

A.   River catchments that store high amounts of nutrients dissolved  ingroundwater or trapped in soils

B.   Eutrophication

C.   Dearth of nearby healthy populations of marine plants & animals that can provide the seed stock

D.   All of these

A.   Landmark iniatives to maintain runoff nutrients also need to be put into effect. 

B.   Comprehensive plans must be in place in order to prevent nitrogen and phosphorus from getting into the water. 

C.   Governments have to reduce the intensity of commercial fishing activities.

D.   Governments must make sure economic development does not lead to resurgence of nutrients into the sea. 

E.   All of these

A.   Mussels eliminate all other animals that can live there.

B.   Mussels release too many nutrients.

C.   Mussels filter water but bacterial decomposition consumes as large amount of oxygen. The end result is the mussels collapse from low oxygen.

D.   Mussels use so little oxygen that once the nutrients fall other animals out compete them and cause the mussels to collapse.

A.   No

B.   Yes