The ocean is an ideal subject of this approach because of its enormous microbiota, whose biomass equals that of all other living organisms on earth is mostly microbial, and also because most of these microbes are extremely fastidious to cultivate.
Craig Venter pioneered these studies and has sampled the surface of the World oceans, but has only scraped the surface. Only one study carried out in Hawaii Ocean Time Series (or HOT) station has analyzed the metagenome of different depths down to 4000m showing the enormous diversity hidden there. This article describes the second study of the bathypelagic region, in this case at a station located over the Ionian abyssal plain, a flat deep basin occupying most of the space between Sicily and Greece in the Eastern Mediterranean. The deep waters of the Mediterranean are special in being free from the intrusion of polar waters that feed most the bottom of the global ocean. The Ionian sample comes from 3000 m deep and is submitted to a continuous pressure of 300 Kg/cm2 but contrastingly to most deep ocean habitats this has a relatively warm temperature of nearly 14ºC.
In general, a remarkable number of similarities were found with the deep meso-pelagic Pacific and a convergence at the level of taxa found and types of metabolism with the soil microbiota is starting to be perceived. The authors use the term “invisible soil” paraphrasing the “invisible forest” coined by Paul Falkowski to refer to the hidden but gigantic primary productivity found in the photic zone. The diversity of metabolic enzymes involved in resilient organic compounds degradation was very high. However, many microbes could complement their heterotrophic metabolism with chemolithotrophic energy supplies and, specifically in the Mediterranean, the oxidation of carbon monoxide, probably released by tectonic activity, could be important. There is also evidence that the microbes rarely live isolated. The free living planktonic lifestyle is probably not very popular in this extremely depleted environment. Quorum sensing genes indicate that instead, microbes tend to aggregate in particles and they could become luminescent maybe to attract and be eaten by animals. This strategy could provide the cells with a sporadic visit to the nutritious oasis of an animal gut. Overall, this paper shows that the deep ocean possesses a rich and mostly unknown microbiota that deserves much more studies.
A recent analysis of a metagenomic library from the deep Mediterranean shows a surprising high number of quorum sensing or lux genes that are only expressed when bacteria live in colonies. The deep ocean might be too depleted in resources for microbes to live independently. Instead the association to detritus particles might give them a rich microenvironment. Now, some of the genes detected have been positively identified as luxA, directly involved in bioluminescence.
Why would deep sea bacteria be luminescent? One possible explanation is that they become attractive to animals that at these depths are very photosensitive. Being swallowed by one of these creatures would give the bacteria a temporary oasis of nutrient-rich conditions before another long dip in the abyssal black.
Dr Rodriguez-Valera’s paper, entitled, “Metagenomics of the Deep Mediterranean, a Warm Bathypelagic Habitat,” appears in the online, open-access journal PLoS ONE on September 19.
Andrew Hyde | alfa
Scientists turn carbon emissions into usable energy
21.01.2019 | Ulsan National Institute of Science and Technology (UNIST)
Ten-year anniversary of the Neumayer Station III
18.01.2019 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
So-called bifacial stem cells are responsible for one of the most critical growth processes on Earth – the formation of wood.
Immune cells called macrophages are supposed to serve and protect, but cancer has found ways to put them to sleep. Now researchers at the Abramson Cancer...
The scientific and political community alike stress the importance of German Antarctic research
Joint Press Release from the BMBF and AWI
The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...
World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles
The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.
Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.
In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...
16.01.2019 | Event News
14.01.2019 | Event News
12.12.2018 | Event News
22.01.2019 | Life Sciences
22.01.2019 | Architecture and Construction
22.01.2019 | Life Sciences