*Editorial* **Food Chains and Food Webs in Aquatic Ecosystems**

**Ihn-Sil Kwak 1 and Young-Seuk Park 2,\***


Received: 10 July 2020; Accepted: 17 July 2020; Published: 21 July 2020

**Abstract:** Food chains and food webs describe the structure of communities and their energy flows, and they present interactions between species. Recently, diverse methods have been developed for both experimental studies and theoretical/computational studies on food webs as well as species interactions. They are e ffectively used for various applications, including the monitoring and assessment of ecosystems. This Special Issue includes six empirical studies on food chains and food webs as well as e ffects of environmental factors on organisms in aquatic ecosystems. They confirmed the usefulness of their methods including isotope, DNA-barcoding with gu<sup>t</sup> contents, and environmental DNA for biological monitoring and ecosystem assessment.

**Keywords:** food web; food chain; aquatic ecosystems; monitoring; assessment; environmental DNA; isotope; NGS
