Learn Polish: Równowaga w tym ekosystemie jest bardzo delikatna. - The balance in this ecosystem is very delicate.

Yes! It's a compound noun made from równy (equal) and waga (weight or scale). While it literally means "equal weight," it is the standard Polish word for "balance" or "equilibrium." You can use it for physical balance, ecological equilibrium, or abstract concepts like równowaga psychiczna (mental balance).

Does the international loanword ekosystem decline just like a native Polish noun here?

Exactly. Many English speakers hesitate when declining scientific or modern loanwords, but ekosystem is fully naturalized in Polish. Because it's a masculine inanimate noun ending in a hard consonant (-m), it takes the standard -ie ending in the Locative case after the preposition w, becoming w tym ekosystemie.

Could delikatna be translated as "fragile" in this context?

Absolutely. The Polish adjective delikatny has a slightly broader scope than the English "delicate." Depending on the context, it can mean delicate, fragile, gentle, or subtle. When talking about an ecosystem, "fragile" is often the most natural-sounding English translation.

Since we are learning nie tylko ..., lecz także ..., how would I use that structure to say the balance is not only delicate but also important?