scholarly journals Geochemistry of Tetrapyrrole, Tetraterpenoid, and Perylene Pigments in Sediments from the Gulf of California: Deep Sea Drilling Project Leg 64, Sites 474, 477, 479, and 481, and Scripps Institution of Oceanography Guaymas Basin Survey Cruise Leg 3, Sites 10G and 18G

Author(s):  
E.W. Baker ◽  
J.W. Louda
2015 ◽  
Vol 12 (18) ◽  
pp. 5455-5479 ◽  
Author(s):  
M. Portail ◽  
K. Olu ◽  
E. Escobar-Briones ◽  
J. C. Caprais ◽  
L. Menot ◽  
...  

Abstract. Understanding the ecological processes and connectivity of chemosynthetic deep-sea ecosystems requires comparative studies. In the Guaymas Basin (Gulf of California, Mexico), the presence of seeps and vents in the absence of a biogeographic barrier, and comparable sedimentary settings and depths offers a unique opportunity to assess the role of ecosystem-specific environmental conditions on macrofaunal communities. Six seep and four vent assemblages were studied, three of which were characterised by common major foundation taxa: vesicomyid bivalves, siboglinid tubeworms and microbial mats. Macrofaunal community structure at the family level showed that density, diversity and composition patterns were primarily shaped by seep- and vent-common abiotic factors including methane and hydrogen sulfide concentrations, whereas vent environmental specificities (higher temperature, higher metal concentrations and lower pH) were not significant. The type of substratum and the heterogeneity provided by foundation species were identified as additional structuring factors and their roles were found to vary according to fluid regimes. At the family level, seep and vent similarity reached at least 58 %. All vent families were found at seeps and each seep-specific family displayed low relative abundances (< 5 %). Moreover, 85 % of the identified species among dominant families were shared between seep and vent ecosystems. This study provides further support to the hypothesis of continuity among deep-sea seep and vent ecosystems.


ZooKeys ◽  
2018 ◽  
Vol 764 ◽  
pp. 1-25
Author(s):  
Samuel Gómez

To date, three species of the family Ancorabolidae, three species of the family Argestidae, and one species of the family Rhizothrichidae are known from the deep sea of the Gulf of California. The descriptions of two new species,Eurycletodesparaephippigersp. n.andOdiliacletodessecundussp. n.collected from the Southern Trough of Guaymas Basin at 1440 m and 1642 m depths, respectively, are presented herein. The closest relatives of these two species,E.ephippigerPor, 1964 andO.gracilisSoyer, 1964 are known from the Mediterranean, but some relatives have been reported also from the southern Atlantic.Eurycletodesparaephippigersp. n.is undoubtedly related toE.ephippigerPor, 1964 known from Israel and Banyuls-sur-Mer (France). These two species can be separated by the armature complement of the basis of the maxillule, by the armature complement of the syncoxa of the maxilliped, and by the relative position of the anal operculum.Odiliacletodessecundussp. n.showed to be closely related toO.gracilisSoyer, 1964 known from Banyuls-sur-Mer only. The latter two species can be separated by the armature complement of the syncoxa of the maxilliped, by the structure of the antenna, and by the inner armature complement of the third exopodal segment of the fourth swimming leg.


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