Biodiversity on the Rocks: Macrofauna Inhabiting Authigenic Carbonate at Costa Rica Methane Seeps

• DOI: 10.1371/journal.pone.0131080
• Publication Date: 2015-07-09T19:48:44Z
• Authors: Lisa A. Levin; Guillermo F. Mendoza; Benjamin M. Grupe; Jennifer P. Gonzalez; Brittany Jellison; Greg Rouse; Andrew R. Thurber; Anders Waren
• Keywords: Authigenic; Cold seep; Petroleum seep; Macrobenthos

Carbonate communities: The activity of anaerobic methane oxidizing microbes facilitates precipitation vast quantities authigenic carbonate at seeps. Here we demonstrate the significant role rocks in promoting diversity by providing unique habitat and food resources for macrofaunal assemblages seeps on Costa Rica margin (400–1850 m). attendant fauna is surprisingly similar to that rocky intertidal shores, with numerous grazing gastropods (limpets snails) as dominant taxa. However, community feeds upon seep-associated microbes. Macrofaunal density, composition, carbonates vary a function seepage activity, biogenic location. non-seeping (inactive) sites strongly related hydrography (depth, temperature, O2) overlying water, whereas active not. Densities are highest from tubeworm bushes mussel beds, particularly Mound 12 location (1000 Species higher exposed seepage, multiple species polychaetes dominant, while crustaceans, cnidarians, ophiuroids were better represented inactive sites. Macro-infauna (larger than 0.3 mm) tube cores taken nearby seep sediments comparable depths exhibited densities those rocks, but had lower different taxonomic composition. Seep ampharetid, dorvilleid, hesionid, cirratulid lacydoniid polychaetes, more gastropods, well syllid, chrysopetalid polynoid polychaetes. Stable isotope signatures metrics: stable heterogeneous, sources nutrition used animals. δ13Cinorg values (mean = -26.98‰) ranged -53.3‰ +10.0‰, significantly heavier δ13Corg -33.83‰), which -74.4‰ -20.6‰. Invertebrates average δ13C (per rock) -31.0‰ (range -18.5‰ -46.5‰) δ15N 5.7‰ -4.5‰ +13.4‰). Average did not differ between sites; both settings depend chemosynthesis-based nutrition. Community metrics reflecting trophic (SEAc, total Hull Area, ranges δ15N) packing distance centroid, nearest neighbor distance) also or site. distinct isotopic observed among related, co-occurring intense microbial resource partitioning. Overall, substrate nutritional heterogeneity introduced act promote diverse, uniquely adapted assemblages, even after ceases. macrofauna these ecosystems remain largely overlooked most surveys, major contributors biodiversity chemosynthetic deep sea general.