Question

ecodetectives: peril river
dissolved oxygen data:
below are some important values for dissolved oxygen:
0-2 mg/l: not enough oxygen to support life.
2-4 mg/l: only a few fish and aquatic insects can survive.
4-7 mg/l: good for many aquatic animals, low for cold water fish
7-11 mg/l: very good for most stream fish
source: http://fosc.org/wqdata/wqparameters.htm
click the site that
is likely to have
more fish!
test site 1 (blue
water) average
dissolved oxygen: 9
mg/l
test site 2 (green
water) average
dissolved oxygen: 3
mg/l

Explanation:

Step1: Analyze Test Site 1 DO

Test Site 1 has 9 mg/L DO. From the data, 7 - 11 mg/L is "very good for most stream fish". So Test Site 1's DO is in a range good for many fish.

Step2: Analyze Test Site 2 DO

Test Site 2 has 3 mg/L DO. The range 2 - 4 mg/L says "only a few fish and aquatic insects can survive". So Test Site 2 has fewer fish - supporting conditions.

Step3: Compare the two sites

Since 9 mg/L (Test Site 1) is in a range better for fish survival than 3 mg/L (Test Site 2), Test Site 1 is more likely to have more fish.

Answer:

Test Site 1 (Blue Water)