1.which of the following is true about light and depth in an aquatic ecosystems? a. light increases as depth increases b. light decreases as depth increases c. light stays the same as depth increases d. light is not dependent on depth 2.a student collects a sample of water in florida with a high salinity. where is the most likely place for this water to have come from? a. st johns river b. pond at school c. atlantic ocean d. lake okeechobee

Answer 1:

            The correct option is B. “Light decreases as depth increases”.  

Explanation:

             Light is one of the most important environmental factor the determine the depth of ocean and divide it into different zones, which are listed below:

1. Photic zone:

               This zone is composed of phytoplanktons which photosynthesize and prepare their food in the presence of sunlight. This zone reaches to 200 meter from surface.

2. Aphotic Zone:

                   The zone in water colum deeper than 200 meter where light cannot penetrate is known as aphotic zone.  

Answer 2:  

             The correct option is C.

Reason

           Based on presence of dissolved salt water body can be classified into two main groups.

1. Fresh water:  

            Water which contain less than 1gram of dissolved solids per liter is known as fresh water.  

Example:

               Lakes, river, stream and even under ground water.

2.  Sea water:

              Water which contain more than 1 gram dissolved solids per liter is known as sea water. Sea water contain more salt as compared to fresh water and increases due to evaporation of water from surface. Sea water has a salinity of about 35 gram per liter of water.  

Example:  

              Water from sea or ocean.

Conclusion

              From the above description it is cleared that student who collects a sample of water in Florida with a high salinity level Atlantic ocean. Because St John river, pond at school and lake Okeechobee belong to fresh water body.