Only a few studies have reported on viral dynamics in estuarine environments, and the factors regulating viral ecology are not well known. We herein aimed to address the factors controlling virus–host relationships in tropical estuaries. To accomplish this, we combine a historical data series (2011–2017), containing virus and prokaryote abundances, with environmental data from Guanabara Bay, Brazil. Water quality gradients and tides were found to regulate the structure of prokaryotic communities, and seasonal patterns added complexity to the dynamics of viral populations. Prediction models showed a balance between expected and recorded virus–host relationships. However, changes in virus-microbial ratio (VMR) were found in areas with microorganism increases and regions showing critical environmental changes. Our results demonstrated that VMR changes are multifactorial and cannot be associated with any specific factor. Neither Kill-the-Winner nor Piggyback-the-Winner models can predict VMR in a highly dynamic environment strongly influenced by eutrophication. In sum, it can be concluded that special care is necessary when analyzing models for predicting virus and host abundances, as ecological factors control host distribution and play a significant role in the virus–host relationship.

中文翻译：

---

热带河口系统中浮游病毒的发生和作用

只有少数研究报道了河口环境中的病毒动力学，调节病毒生态的因素尚不清楚。我们在此旨在解决控制热带河口病毒-宿主关系的因素。为了实现这一点，我们将包含病毒和原核生物丰度的历史数据系列（2011-2017）与巴西瓜纳巴拉湾的环境数据相结合。发现水质梯度和潮汐调节原核生物群落的结构，季节性模式增加了病毒种群动态的复杂性。预测模型显示了预期和记录的病毒-宿主关系之间的平衡。然而，在微生物增加的地区和环境发生严重变化的地区发现了病毒-微生物比 (VMR) 的变化。我们的结果表明 VMR 变化是多因素的，不能与任何特定因素相关联。Kill-the-Winner 和 Piggyback-the-Winner 模型都无法预测受富营养化影响强烈的高动态环境中的 VMR。总之，可以得出结论，在分析预测病毒和宿主丰度的模型时需要特别小心，因为生态因素控制宿主分布并在病毒-宿主关系中发挥重要作用。