What is the result when you total the individual percent abundances?

100 %

%Abundance = part / total *100
%Abundance_1 = parts_1 / total * 100
%Abundance_2 = parts_2 / total * 100
%Abundance_3 = parts_3 / total * 100

 %Abundace_1 + %Abundace_2+%Abundace_3 = parts_1/total *100 + parts_2/total*100 + parts_3/total*100

Factor the right side:

%Abundace_1 + %Abundace_2+%Abundace_3 = [parts_1+parts_2+part2_3]/total *100

Given the sum of the parts = total 

 %Abundace_1 + %Abundace_2+%Abundace_3 = [total]/total *100 = 100

So, the sum of the individual % of abundaces is 100 %.