Let
K
K
be a knot in an L-space
Y
Y
with a Dehn surgery to a surface bundle over
S
1
S^1
. We prove that
K
K
is rationally fibered, that is, the knot complement admits a fibration over
S
1
S^1
. As part of the proof, we show that if
K
⊂
Y
K\subset Y
has a Dehn surgery to
S
1
×
S
2
S^1 \times S^2
, then
K
K
is rationally fibered. In the case that
K
K
admits some
S
1
×
S
2
S^1 \times S^2
surgery,
K
K
is Floer simple, that is, the rank of
H
F
K
^
(
Y
,
K
)
\widehat {HFK}(Y,K)
is equal to the order of
H
1
(
Y
)
H_1(Y)
. By combining the latter two facts, we deduce that the induced contact structure on the ambient manifold
Y
Y
is tight.
In a different direction, we show that if
K
K
is a knot in an L-space
Y
Y
, then any Thurston norm minimizing rational Seifert surface for
K
K
extends to a Thurston norm minimizing surface in the manifold obtained by the null surgery on
K
K
(i.e., the unique surgery on
K
K
with
b
1
>
0
b_1>0
).