Answer: 130 meters
Step-by-step explanation:
We have to let the "surface of the ocean" be at 0 height.
So,
anything above surface has POSITIVE height
and anything below surface has NEGATIVE height
The albatross is 100 m above, so we can say its height is:
+100 meters
The shark is 30 m below, so we can say its height is:
-30 meters
The difference in height is thus:
100 - (-30) = 100 + 30 = 130 meters