Shallow Hydrothermal Fluids Shape Microbial Dynamics at the Tagoro Submarine Volcano (Canary Islands, Spain)

Area of Science:

• Marine Biology
• Oceanography
• Geochemistry

Background:

• Shallow underwater hydrothermal systems are crucial yet understudied marine environments.
• The Tagoro submarine volcano provides a unique, long-term model for investigating diffuse hydrothermal fluid impacts.

Purpose of the Study:

• To assess the effects of Tagoro's hydrothermal fluids on phytoplankton and bacterial communities.
• To understand how these inputs influence primary production and biogeochemical cycling in shallow waters.

Main Methods:

• Experimental manipulation of hydrothermal fluid dilution levels.
• Monitoring of chlorophyll a concentration, picoeukaryote and Synechococcus abundances.
• Analysis of phytoplankton and bacterial community composition shifts.

Main Results:

• Chlorophyll a concentrations doubled with hydrothermal enrichment, peaking earlier than controls.
• Small eukaryotic phytoplankton, dinoflagellates, diatoms, and radiolarians showed increased abundance.
• Both phototrophic and chemoautotrophic bacteria benefited, indicating enhanced microbial activity.

Conclusions:

• Shallow hydrothermal systems significantly enhance primary production via phototrophic microbes.
• Hydrothermal inputs stimulate microbial communities, influencing nutrient and element cycling.
• Protistan grazing and parasitism play key roles in regulating these planktonic communities.