All of nature, from the vast oceans to the open fields, unites to express joy and offer praise to God. This grand display includes not only the physical elements of the earth but also all the living creatures that dwell within them.
The ocean makes a mighty, trembling noise, storming with a power similar to a loud clap of thunder [מצודת ציון, ביאור שטיינזלץ]. The sound of crashing waves paints a picture of the sea singing its own unique song [ביאור שטיינזלץ]. It does not roar alone; every creature and animal filling the waters joins in this loud expression of praise [רש״י, מצודת דוד]. Alongside the waters, the open fields are also called upon to experience and share in this deep gladness and joy [מצודת ציון, ביאור שטיינזלץ].
There are two distinct reasons for this worldwide celebration. On a historical level, nature's joy is a direct response to the Ark of the Covenant returning to the Israelites. It acts as an expression of gratitude for the righteous justice God delivered upon the Philistines [רש״י]. Looking toward the future, this scene serves as a broader metaphor. The sea, the fields, and all living things that were created to serve humanity will eventually rejoice and cheer when God arrives to judge the earth. As God reveals His wonders and strength to the nations, all will recognize Him, praising Him for His constant kindness and careful guidance [רלב״ג].