# Diversity and Ecological Potentials of Marine Viruses Inhabiting Continental Shelf Seas

## TL;DR

This study explores the diversity and ecological roles of viruses in China's continental shelf seas, revealing high viral novelty and seasonal changes.

## Contribution

The study provides the largest viral genome dataset from a continental shelf sea, highlighting unprecedented viral novelty and ecological insights.

## Key findings

- Over half of the identified viral operational taxonomic units (vOTUs) are novel, indicating high viral diversity in the eastern continental shelf seas of China.
- Viral communities show significant seasonal and regional shifts, reflecting environmental variability in the study area.
- 20,146 auxiliary metabolic genes are identified, with enrichment in carbohydrate, sulfur, and photosynthetic pathways compared to other marine ecosystems.

## Abstract

Viruses are critical components of all marine ecosystems. However, the role of viruses in continental shelf seas, which are usually areas of intense economic development, remain poorly characterized. Here, 62 seawater viromes from the eastern continental shelf seas of China (ECSSC), collected between 2017 and 2022, are systematically analyzed. A total of 310,628 viral operational taxonomic units (vOTUs) are identified, providing the most comprehensive overview of DNA viral communities in the ECSSC. Among them, 136,652 (42.3%) vOTUs could be classified into 89 families, dominated by Kyanoviridae, Autographiviridae and Zobellviridae. Only 31,994 (10.3%) of the vOTUs have predicted putative hosts, of which 91.4% are associated with specific hosts, including 31 bacterial and 10 archaeal phyla. The uniqueness and novelty of viruses from the ECSSC are identified and found to be much greater than those from GOV 2.0 and other environmental viromes. Viral communities undergo significant seasonal changes in different seasons and regions of the ECSSC. Here, 20,146 auxiliary metabolic genes are identified, of which carbohydrate, sulfur, and photosynthetic pathways are significantly enriched in the ECSSC compared to other marine ecosystems. This study establishes a foundational baseline for seawater viruses in the ECSSC, highlighting viral diversity and its potential impact on the biogeochemistry of continental shelf sea ecosystems.

To the best of the knowledge, this study provides the largest viral genome dataset from a continental shelf sea. It reveals that over half of vOTUs are novel, highlighting the remarkable viral novelty in the eastern continental shelf seas of China (ECSSC). Viral communities exhibit pronounced seasonal and regional shifts, reflecting environmental heterogeneity. A total of 20 146 AMGs are identified, with those involved in carbohydrate, sulfur, and photosynthetic pathways being significantly enriched in the ECSSC.