Review Lecture - The chemosynthetic support of life and the microbial diversity at deep-sea hydrothermal vents

1985 ◽  
Vol 225 (1240) ◽  
pp. 277-297 ◽  

Circulation of seawater through the upper few kilometres of oceanic crust at tectonic spreading zones results in a transformation of geothermal into chemical energy. Reduced inorganic species are emitted from warm (under 25 °C) and hot (under 400 °C) vents on the sea floor at depths of 1600 and 3000 m and are used by chemolithotrophic bacteria as terrestrial sources of energy for the primary production of organic carbon from carbon dioxide. Thus, the rich and unique animal populations found in the immediate vicinity of the vents represent ecosystems that are largely or totally independent of solar energy. They subsist by means of a food chain that is based on various microbial processes. In addition to aerobic and anaerobic bacterial chemosynthesis, a new type of symbiosis between yet undescribed chemolithotrophic prokaryotes and certain invertebrates appears to account for the major part of the total primary production at the deep-sea vent sites.

Author(s):  
Futa Nakasugi ◽  
Motohiro Shimanaga ◽  
Hidetaka Nomaki ◽  
Hiromi Kayama Watanabe ◽  
Tomo Kitahashi ◽  
...  

Abstract Dirivultid copepods (Siphonostomatoida), one of the most successful meiobenthic organisms found at deep-sea hydrothermal vents, have been the focus of most previous ecological studies among meiofauna in these habitats. The ecology of Harpacticoida, a major benthic copepod group in typical deep-sea floor, however, is not well understood in terms of variations in community structure and controlling factors at venting sites. The spatial heterogeneities in benthic harpacticoid composition and their association with environmental parameters were investigated at hydrothermal vent chimney structures in the calderas of three neighbouring sea knolls (Bayonnaise Knoll, Myojin Knoll and Myojin-sho Caldera) in the western North Pacific. While a previous study had reported the distribution of dirivultids was strongly associated with spatial differences in stable carbon isotopic signatures (δ13C) of organic matter in the detritus on active chimneys in the field, multivariate analyses detected no significant corelation between the parameter and harpacticoid composition in this study. Instead, high associations of the harpacticoid composition with differences in water depth and total organic carbon (TOC) concentration were detected. Ectinosomatidae dominated at vent sites with lower TOC values in the shallowest Bayonnaise Knoll, while they were less prevalent at deeper vent fields in the other knolls, where Miraciidae was the most abundant family. This study indicated the availability of vent chemoautotrophic carbon is not a primary factor controlling the composition of harpacticoids even in the habitats on the hydrothermal vents, but instead by the food amount, regardless of its resources (including marine snow from the sea surface), in the study area.


Science ◽  
1980 ◽  
Vol 207 (4437) ◽  
pp. 1345-1347 ◽  
Author(s):  
D. M. Karl ◽  
C. O. Wirsen ◽  
H. W. Jannasch

1986 ◽  
Vol 227 (1246) ◽  
pp. 145-145

Review Lecture. The chemosynthetic support of life and the microbial diversity at deep-sea hydrothermal vents. Proc. R. Soc. Lond . B 225, 277-297 (1985). In this lecture, the chemosynthetic base of the food chain supporting rich deep-sea ecosystems around hydrothermal vents, was claimed to represent a primary production of organic carbon independent of sunlight. I received several comments criticizing this point of view for neglecting the fact that oxygen is the required electron acceptor in the metabolism of the eukaryotic part of the vent communities. I agree. The independence of light was, however, mentioned in connection with a catastrophic darkening of the globe’s surface. A temporary absence of photo­synthetic oxygen production might well be overcome for an extended period of time by the ‘aerobic’ deep-sea vent animals, given the minute consumption of oxygen relative to its huge total quantity available in deep ocean waters. In a permanent absence of light, however, the existence of eukaryotic organisms, as we know them, will depend on an oxygen-producing process such as photosynthesis. Populations of anaerobic bacteria, on the other hand, may well persist and differentiate into prokaryotic ecosystems in permanent darkness as long as the geothermal provision of H 2 and CO 2 continues. Physical chemists were troubled by the use of the term ‘source of energy’ for reduced inorganic compounds, such as H 2 S, in chemosynthesis because the actual amount of free energy available depends on the reaction with the oxidant. It is certainly true that the common equalization of the terms ‘electron donor’ and ‘energy source’ in microbial physiology does not take the specific type of electron acceptor into account. They are used as terms of convenience. In my discussion of deep-sea chemosynthesis as a form of primary production, the emphasis on terrestrial chemical ‘sources of energy’ was meant to illustrate the contrast to the use of solar energy which does not only supply oxygen as the most efficient electron acceptor but also the common electron donors, organic as well as inorganic, for all non-phototrophic life in surface waters and on the continents.


Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1324
Author(s):  
Shamik Dasgupta ◽  
Xiaotong Peng ◽  
Kaiwen Ta

The discovery of deep-sea hydrothermal vents in the late 1970s widened the limits of life and habitability. The mixing of oxidizing seawater and reduction of hydrothermal fluids create a chemical disequilibrium that is exploited by chemosynthetic bacteria and archaea to harness energy by converting inorganic carbon into organic biomass. Due to the rich variety of chemical sources and steep physico-chemical gradients, a large array of microorganisms thrive in these extreme environments, which includes but are not restricted to chemolithoautotrophs, heterotrophs, and mixotrophs. Past research has revealed the underlying relationship of these microbial communities with the subsurface geology and hydrothermal geochemistry. Endolithic microbial communities at the ocean floor catalyze a number of redox reactions through various metabolic activities. Hydrothermal chimneys harbor Fe-reducers, sulfur-reducers, sulfide and H2-oxidizers, methanogens, and heterotrophs that continuously interact with the basaltic, carbonate, or ultramafic basement rocks for energy-yielding reactions. Here, we briefly review the global deep-sea hydrothermal systems, microbial diversity, and microbe–mineral interactions therein to obtain in-depth knowledge of the biogeochemistry in such a unique and geologically critical subseafloor environment.


1987 ◽  
Vol 65 (10) ◽  
pp. 2443-2449 ◽  
Author(s):  
Verena Tunnicliffe ◽  
R. Gordon Jensen

Over 200 individuals of the majid crab Macroregonia macrochira Sakai, 1978 were examined on submersible and towed camera photographs from the Juan de Fuca and Explorer ridges. The crab is found at bathyal depths and shows a preference for hard substrata. Its attraction to the food source at hydrothermal vents is reflected in the high population concentrations around vent sites of the northeast Pacific. Mature males, distinguished by their large chelipeds, tend to be widely dispersed while the female–juvenile group clusters in and around vents. Stomachs of captured specimens contain remains of vent animals, confirming, along with submersible observations, that this crab is a major predator of animals at these vents. Other aspects of M. macrochira biology suggest that the sexes are separable on the basis of carapace aspect ratio, that polygamy is not apparent, and that planktotrophic larvae are released. The crab's ability to range both in and away from vents makes it an excellent indicator of the proximity of hydrothermal activity. In addition, it represents a mechanism for transferring the rich production of chemosynthetic activity to the oligotrophic deep-sea environment.


Author(s):  
Xikun Song ◽  
Mingxin Lyu ◽  
Xiaodi Zhang ◽  
Bernhard Ruthensteiner ◽  
In-Young Ahn ◽  
...  
Keyword(s):  
Deep Sea ◽  

Archaea ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Franziska Wemheuer ◽  
Avril Jean Elisabeth von Hoyningen-Huene ◽  
Marion Pohlner ◽  
Julius Degenhardt ◽  
Bert Engelen ◽  
...  

Information on environmental conditions shaping archaeal communities thriving at the seafloor of the central Pacific Ocean is limited. The present study was conducted to investigate the diversity, composition, and function of both entire and potentially active archaeal communities within Pacific deep-sea sediments. For this purpose, sediment samples were taken along the 180° meridian of the central Pacific Ocean. Community composition and diversity were assessed by Illumina tag sequencing targeting archaeal 16S rRNA genes and transcripts. Archaeal communities were dominated by CandidatusNitrosopumilus(Thaumarchaeota) and other members of theNitrosopumilaceae(Thaumarchaeota), but higher relative abundances of the Marine Group II (Euryarchaeota) were observed in the active compared to the entire archaeal community. The composition of the entire and the active archaeal communities was strongly linked to primary production (chlorophyll content), explaining more than 40% of the variance. Furthermore, we found a strong correlation of the entire archaeal community composition to latitude and silicic acid content, while the active community was significantly correlated with primary production and ferric oxide content. We predicted functional profiles from 16S rRNA data to assess archaeal community functions. Latitude was significantly correlated with functional profiles of the entire community, whereas those of the active community were significantly correlated with nitrate and chlorophyll content. The results of the present study provide first insights into benthic archaeal communities in the Pacific Ocean and environmental conditions shaping their diversity, distribution, and function. Additionally, they might serve as a template for further studies investigating archaea colonizing deep-sea sediments.


Author(s):  
Michel Praet-Van

This ultrastructural investigation of gametogenesis in a deep-sea anemone of the Bay of Biscay trawled around 2000 m depth, contributes to the knowledge of biology and strategy of reproduction of deep-sea benthos.This sea anemone is dioecious. The sperm appears very similar to those of shallow water sea anemones of the genus, Calliactis. The ultrastructural investigation of oogenesis allows the characteristics of the stages of previtellogenesis and vitellogenesis to be defined. The latter begins with a period of lipogenesis correlated with the formation of a trophonema. Mature oocytes measure up to 180 (im in diameter. Study of spermatogenesis and oogenesis reveals that spawning occurs in April/May. In males, the main area of testicular cysts, full of sperm, reaches maximal development from March to May and, in females, the percentage of mature oocytes decreases from 33% in April to 1% in May.Spawning may be induced by the advent in the deep-sea of the products of the spring phytoplankton bloom. This period of spawning, during the increased deposition of organic matter to the deep-sea floor, may be an advantageous strategy for early development of Paracalliactis.


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