Hydrothermal vent fields discovered in the southern Gulf of California clarify role of habitat in augmenting regional diversity

Abstract

Hydrothermal vent communities are distributed along mid-ocean spreading ridges as isolated patches. While distance is a key factor influencing connectivity among sites, habitat characteristics are also critical. The Pescadero Basin (PB) and Alarcón Rise (AR) vent fields, recently discovered in the southern Gulf of California, are bounded by previously known vent localities (e.g. Guaymas Basin and 218 N East Pacific Rise); yet, the newly discovered vents differ markedly in substrata and vent fluid attributes. Out of 116 macrofaunal species observed or collected, only three species are shared among all four vent fields, while 73 occur at only one locality. Foundation species at basalt-hosted sulfide chimneys on the AR differ from the functional equivalents inhabiting sediment-hosted carbonate chimneys in the PB, only 75 km away. The dominant species of symbiont-hosting tubeworms and clams, and peripheral suspension-feeding taxa, differ between the sites. Notably, the PB vents host a limited and specialized fauna in which 17 of 26 species are unknown at other regional vents and many are new species. Rare sightings and captured larvae of the 'missing' species revealed that dispersal limitation is not responsible for differences in community composition at the neighbouring vent localities. Instead, larval recruitment-limiting habitat suitability probably favours species differentially. As scenarios develop to design conservation strategies around mining of seafloor sulfide deposits, these results illustrate that models encompassing habitat characteristics are needed to predict metacommunity structure.

Characterization of Methane-Seep Communities in a Deep-Sea Area Designated for Oil and Natural Gas Exploitation Off Trinidad and Tobago

“…Notably absent were vesicomyid clam communities common in the Pacific. There are also some affinities with taxa reported from the newly discovered Pescadero Transform Fault at 2,400 m in the Guaymas Basin (Goffredi et al, 2017). Thus, similarities of the Atlantic equatorial belt seep fauna may extend into the Pacific, with depth zonation playing a key role in community structure .…”

Geology of the Alarcon Rise, Southern Gulf of California

“…All four active vent fields are located in AR2 (Figures A and B) and occur roughly centered on the shallowest inflated portion along slightly more than 2 km of the axis. The biological communities at three of the four active vent fields (Goffredi et al, ) and the fluid compositions (Spelz et al, ), deposit descriptions, and bulk compositions (Paduan et al, ) are described elsewhere.…”

Exploring the Ecology of Deep-Sea Hydrothermal Vents in a Metacommunity Framework

“…Within a region, individual vent patches rarely host the full species pool . In some regions, neighboring vents may differ strikingly in species composition, as has been observed in the mid-Atlantic (Desbruyères et al, 2001) western Pacific (Podowski et al, 2010;Metaxas, 2011), and Gulf of California (Goffredi et al, 2017). In contrast, in the eastern Pacific, individual vents tend to host a subset of the province's species pool, without geographic clines (Juniper et al, 1990;Van Dover and Hessler, 1990).…”