Water In Frozen Lake Diagram What If The Water Phase Diagram Was Positive Rather Then Negative?

What if the water phase diagram was positive rather then negative? - water in frozen lake diagram

If the slope of the line for the phase diagram of solid / liquid water were more positive than negative, what would the impact on life in the water during periods of temperatures below zero? Explaining.

I'm kind of thinking, because ice is less dense then liquid water when you freeze freeze down to the upper lake Swtich then on the ground and water, and so on until all the frozen lake would freeze life in the water instead of being isolated will die. Is that correct her?