A couple of people survey the sea for wildlife.
There are people underwater.
To survey the sea implies being underwater.
exists e1 x1 x2 x3 x4.(n_sea(x3) & Theme(e1,x3) & Actor(e1,x1) & v_survey(e1) & for(x3,x4) & n_wildlife(x4) & of(x1,x2) & n_people(x2) & n_couple(x1))
exists p1 x1 s1 x2 x3.((x1 = x2) & Theme(s1,x3) & a_underwater(s1) & (x2 = x3) & n_people(x2))