Sweet beaks: What Galapagos finches and marine bacteria have in common

February 19, 2020

The variety of finch species on the remote Galapagos Islands is the most prominent example for Charles Darwin's and Alfred R. Wallace's theory of evolution through natural selection. Galapagos finch species have developed distinct beak sizes and shapes and thereby have adapted to different food sources. This exemplifies how even closely related species can effectively make use of available resources, avoid competition and thus co-occur in the same habitat.

A bloom with great effect

This principle is not limited to macrofauna. It also applies in the realm of marine microbes, the scientists from Bremen now show. Satellite photos taken from coastal areas during warm seasons often show that the ocean is green rather than blue. This color originates from immense numbers of microscopic marine algae - so-called algal blooms. Such blooms are transient: At some point, all nutrients are depleted and predators like protists and viruses have taken their share. The ensuing mass mortality of the algae leads to the release of large quantities of organic matter into the seawater, including algal polysaccharides. These algal sugars are one of the main food sources for heterotrophic marine bacteria.

Tiny niches for tiny organisms

Scientists at the Max Planck Institute for Marine Microbiology in Bremen, Germany, have investigated the bacterial response to spring algal blooms off the island of Heligoland in the German Bight (southern North Sea) for more than a decade. A close-knit microbial community is recurrently abundant during spring blooms in most years. One of the most prominent community members is Polaribacter, a genus of the Flavobacteriia class. From 2009 to 2012, the scientists investigated Polaribacter abundances during spring blooms and identified co-occurring closely related but distinct clades. "We found that these Polaribacter clades are pretty picky when it comes to sugar", reports Burak Avci from the Max Planck Institute for Marine Microbiology. "Or, scientifically spoken: They have rather distinct niches with respect to algal polysaccharides."

This is also reflected in the timing of the clade's occurrence. Different clades tended to show up at different bloom stages. "One clade of presumed first responders is characterized by small genomes with a pronounced protein but limited sugar degradation capacity. In contrast, another clade of presumed late responders has larger genomes and the capacity to utilize more complex polysaccharides", Avci continues. Another clade seems to be tied to presence of a specific algae (genus Chattonella). It is characterized by large genomes and has the most diverse sugar menu of all investigated Polaribacter clades.

Ecological significance

Like Galapagos finches, these results exemplify how also closely-related clades of marine bacteria (here Polaribacter) can forgo direct competition by partitioning available resources (here polysaccharides). "One of the fundamental questions in microbial ecology is which factors shape the composition of a given microbial community. Studies as this one advance our understanding of the principles that govern microbial community composition in such dynamic environments", Avci concludes. This might be especially relevant for bacteria degrading algal blooms, which are an essential part of the global carbon cycle and might become more abundant following increased anthropogenic nutrient input into the oceans and global warming.
-end-


Max Planck Institute for Marine Microbiology

Related Marine Bacteria Articles from Brightsurf:

Switching up: Marine bacteria shift between lifestyles to get the best resources
Researchers from the University of Tsukuba and ETH Zurich have found that marine bacteria exploit resource patches efficiently by switching between attached and planktonic lifestyles, and fine-tuning the time spent on patches depending on their quality.

Marine heatwaves are human made
Heatwaves in the world's oceans have become over 20 times more frequent due to human influence.

Cashing in on marine byproducts
As exploitation of wild fisheries and marine environments threaten food supplies, Flinders University scientists are finding sustainable new ways to convert biowaste, algal biomass and even beached seaweed into valuable dietary proteins and other products.

Saving marine life: Novel method quantifies the effects of plastic on marine wildlife
Scientists at Tokyo Institute of Technology together with their international collaborators developed a novel quantitative method to quantify the effects of plastic on marine animals.

Marine microorganisms: How to survive below the seafloor
Foraminifera, an ancient and ecologically highly successful group of marine organisms, are found on and below the seafloor.

Marine energy devices likely pose minimal impacts to marine life, report shows
On World Oceans Day, an international team of marine scientists reports that the potential impact of marine renewable energy to marine life is likely small or undetectable.

Marine waste management: Recycling efficiency by marine microbes
It was only relatively recently that tiny, single-celled thaumarchaea were discovered to exist and thrive in the pelagic ocean, where their population size of roughly 1028 (10 billion quintillion) cells makes them one of the most abundant organisms on our planet.

Marine litter in the Bay of Biscay
The scientific journal 'Marine Pollution Bulletin' has just published 'Microplastics in the Bay of Biscay: an overview', a piece of work by the 'Materials+Technologies' research group (GMT) of the Faculty of Engineering - Gipuzkoa.

Neanderthals: Pioneers in the use of marine resources
An international team have just demonstrated that Neanderthals hunted, fished, and gathered prodigious volumes of seafood and other marine animals: they discovered remains of molluscs, crustaceans, fish, birds, and mammals in a Portuguese cave (Figueira Brava) occupied by Neanderthals between 106,000 and 86,000 BCE.

Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.

Read More: Marine Bacteria News and Marine Bacteria Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.