Microscopic marine viruses transferring glowing DNA strands to phytoplankton.

Viral Hack: How Ocean Viruses Help Algae Thrive

Nico Varela in Science & Nature August 2025 • 4 min read.

"Tiny ocean viruses can steal genes from their algal hosts to manipulate how they absorb nutrients, helping them survive in nutrient-poor waters. Here’s what that means for the ocean’s food web."

Phytoplankton, the microscopic algae drifting in our oceans, are the unsung heroes of the marine food web. Just like plants on land, they need nutrients to grow, especially nitrogen. But in many ocean areas, nitrogen is scarce, creating a constant struggle for survival.

Adding another layer to this complex picture are marine viruses, the most abundant biological entities in the ocean. Viruses infect and kill phytoplankton, a process that releases nutrients back into the water. But scientists are discovering that these viruses are more than just killers; they're also manipulators.

A groundbreaking study has uncovered that viruses can steal genes from their algal hosts, specifically genes that control how algae absorb nutrients. This means viruses can essentially rewrite the rules of nutrient uptake, giving infected algae a survival advantage. This article explores this fascinating discovery and its implications for understanding ocean ecosystems.

How Viruses 'Hack' Algal Nutrient Absorption

Microscopic marine viruses transferring glowing DNA strands to phytoplankton.

Researchers examined a virus called OtV6, which infects a small green alga named Ostreococcus tauri, a common type of phytoplankton. They discovered that OtV6 carries a gene for an ammonium transporter, a protein that helps algae absorb ammonium, a key form of nitrogen.

The team's experiments revealed the following key points:

Gene Theft: OtV6 acquired the ammonium transporter gene from its algal host.
On-the-Job Training: The virus activates this gene during infection, meaning the infected algae produce the viral ammonium transporter.
Nutrient Boost: This viral transporter changes how the algae take up nitrogen, increasing their ability to absorb different forms of nitrogen from the water.

This is significant because nitrogen availability often limits phytoplankton growth. By equipping their hosts with a better nutrient absorption system, the viruses ensure the algae can continue to grow and support viral replication, even when nitrogen is scarce.

What Does This Mean for the Ocean?

This discovery has major implications for how we understand ocean ecosystems. It shows that viruses aren't just agents of death but can also play a role in shaping the survival strategies of phytoplankton.

Here’s why it matters:

<ul><li>Nutrient Cycles: Viruses can influence how nutrients like nitrogen are cycled through the ocean, affecting the entire food web.</li><li>Algal Blooms: Viral manipulation could contribute to the formation and dynamics of algal blooms.</li><li>Evolution: This highlights how viruses can act as vectors for horizontal gene transfer, driving the evolution of phytoplankton.</li></ul>

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1073/pnas.1708097114, Alternate LINK

Title: Host-Derived Viral Transporter Protein For Nitrogen Uptake In Infected Marine Phytoplankton

Subject: Multidisciplinary

Journal: Proceedings of the National Academy of Sciences

Publisher: Proceedings of the National Academy of Sciences

Authors: Adam Monier, Aurélie Chambouvet, David S. Milner, Victoria Attah, Ramón Terrado, Connie Lovejoy, Hervé Moreau, Alyson E. Santoro, Évelyne Derelle, Thomas A. Richards

Published: 2017-08-21

Everything You Need To Know

What are the key players in this ocean ecosystem interaction?

Phytoplankton, like the microscopic algae Ostreococcus tauri, are the foundation of the marine food web, similar to plants on land. They require nutrients, such as nitrogen, to grow. However, in many ocean environments, nitrogen is scarce, which limits their growth. This study highlights how viruses can influence the survival of these algae by enhancing their nutrient uptake capabilities.

What is the relationship between OtV6 and Ostreococcus tauri?

The study focuses on the interaction between the virus OtV6 and the algae Ostreococcus tauri. OtV6 infects Ostreococcus tauri. During this infection, OtV6 steals a gene from the algae. This gene, an ammonium transporter, allows the infected algae to absorb more nitrogen, increasing their ability to take up nutrients. This helps them grow even when nitrogen levels are low.

How do viruses 'hack' the nutrient absorption of algae?

OtV6, a marine virus, steals the ammonium transporter gene from its host, Ostreococcus tauri. This gene allows the infected algae to absorb different forms of nitrogen more efficiently. By 'hacking' this process, the virus ensures the algae can continue to grow and support viral replication, even when nitrogen is scarce.

What role do viruses play in the survival of algae?

Viruses, like OtV6, aren't just agents of death in the ocean. They can also manipulate their algal hosts, such as Ostreococcus tauri, to enhance nutrient absorption. By stealing and utilizing algal genes, the viruses ensure that their hosts can survive and thrive even in nutrient-poor environments. This manipulation plays a crucial role in the survival strategies of phytoplankton, influencing the overall health and balance of ocean ecosystems.

Why is this discovery important for understanding the ocean?

This discovery has significant implications for our understanding of ocean ecosystems. It shows that marine viruses like OtV6 can actively shape the survival strategies of phytoplankton, such as Ostreococcus tauri. The ability of viruses to 'hack' the nutrient uptake of algae affects the entire marine food web. Understanding these interactions is essential for predicting and managing the effects of environmental changes on the ocean's delicate balance.