( Also ( , ( icebergs ( ( are ( ( ( made ( of ( frozen freshwater ) ) ) , ) ( whereas ( ( ( the ( cold water ) ) ( around them ) ) ( is ( ( ( salty sweater ) ; ) ( ( ( ( ( salt water ) ( has ( ( a ( higher density ) ) ( than freshwater ) ) ) ) , ) so ) ( ( combined ( with ( ( the ( frozen properties ) ) ( of ( the freshwater ) ) ) ) ) ( , ( icebergs float ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (ADVP (RB Also)) (, ,) (NP (NNS icebergs)) (VP (VBP are) (VP (VBN made) (PP (IN of) (NP (JJ frozen) (NN freshwater))) (, ,) (SBAR (IN whereas) (S (NP (NP (DT the) (JJ cold) (NN water)) (PP (IN around) (NP (PRP them)))) (VP (VBZ is) (NP (NP (JJ salty) (NN sweater)) (: ;) (S (S (NP (NN salt) (NN water)) (VP (VBZ has) (NP (NP (DT a) (JJR higher) (NN density)) (PP (IN than) (NP (NN freshwater)))))) (, ,) (IN so) (S (PP (VBN combined) (PP (IN with) (NP (NP (DT the) (JJ frozen) (NNS properties)) (PP (IN of) (NP (DT the) (NN freshwater)))))) (, ,) (NP (NNS icebergs)) (VP (VBP float)))))))))) (. .)))
Also, icebergs are  made of frozen freshwater, whereas the cold water around them is salty sweater; salt water has a higher density than freshwater, so combined with the frozen properties of the freshwater, icebergs float.
(ROOT (S (NP (NNP Density)) (VP (VBZ allows) (SBAR (S (NP (NN cut)) (VP (VBZ logs) (S (VP (TO to) (VP (VB float) (PP (IN on) (NP (NN water)))))))))) (. .)))