RESULTS OF INTERNATIONAL FIELD EXPERIMENT ON A NATURAL CO_2 ANALOGUE

摘要

An international field experiment was conducted during December 2002 at the Loihi seamount in order to investigate a natural analogue of CO_2, and its effects on the surrounding marine biology. This natural CO_2 analogue was investigated as a first order proxy for a purposeful CO_2 injection in order to determine potential effects such as depressed pH and hypercapnia on existing marine ecosystems. Trapping rates at Loihi were much higher than anticipated with a minimum of 1,100 amphipods recovered after a 24 hour deployment despite the loss of many animals through the funnel opening (Fig. 1). Compared to Loihi few (36) amphipods were trapped off South Point (southern most portion of big island of Hawaii); however, the South Point amphipods were larger (Fig. 2) and lithoded crabs (Neollthodes sp.) aggregated around the trap but were too large to enter. On all dives the amphipods remained continuously active during the ascent to the surface until ambient temperatures of between 10 and 11℃ were reached at a depth of about 300 m. From that point activity decreased rapidly until all appeared to be dead soon after the temperature exceeded 13℃ at depths of about 250 m. These data indicate that the state of torpor which the majority of amphipods experienced following a 10-minute exposure to the vent fluids was due to the high CO_2 content and not the elevated temperature.