Cold Seep - in The East Pacific

In The East Pacific

In the deep sea the COMARGE project has studied the biodiversity patterns along and across the Chilean margin through a complexity of ecosystems such as methane seeps and oxygen minimum zones reporting that such habitat heterogeneity may influence the biodiversity patterns of the local fauna. Seep fauna include bivalves of families Lucinidae, Thyasiridae, Solemyidae (Acharax sp.), and Vesicomyidae (Calyptogena gallardoi) and polychates Lamellibrachia sp. and two other polychate species. Furthermore, in these soft reduced sediments below the oxygen minimum zone off the Chilean margin, a diverse microbial community composed by a variety of large prokaryotes (mainly large multi-cellular filamentous "mega bacteria" of the genera Thioploca and Beggiatoa, and of "macrobacteria" including a diversity of phenotypes), protists (ciliates, flagellates, and foraminifers), as well as small metazoans (mostly nematodes and polychaetes) has been found. Gallardo et al. (2007) argue that the likely chemolithotrophic metabolism of most of these mega- and macrobacteria offer an alternative explanation to fossil findings, in particular to those from obvious non-littoral origins, suggesting that traditional hypotheses on the cyanobacterial origin of some fossils may have to be revised.

Cold seeps (pockmark) are also known from depths of 130 m in the Hecate Strait, British Columbia, Canada. Unobvious fauna (also unobvious for cold seeps) has been found there with these dominating species: sea snail Fusitriton oregonensis, anemone Metridium giganteum, encrusting sponges and bivalve Solemya reidi.

Cold seeps with chemosynthetic communities along the USA Pacific coast occur in Monterey Canyon, just off Monterey Bay, California on a mud volcano. There have been found, for example Calyptogena clams Calyptogena kilmeri and Calyptogena pacifica and foraminiferan Spiroplectammina biformis.

• map of cold seeps in the Monterey Bay