Award: OCE-1356738

The main goal of this project was to understand the effect of disturbance on populations at hydrothermal vents.  We analyzed samples of colonists and larvae collected near 10°N on the East Pacific Rise (Fig. 1) after a major eruption in 2006 to try to determine how it affected populations in the areas paved over by the eruption as well as on neighboring sites where the original communities survived.

We collected colonists on settlement surfaces (Fig. 2) at intervals to monitor species abundance and diversity at three vent sites: one in the eruption area (P Vent), one adjacent site where the community survived the eruption (V Vent) and one 35 km south (K Vent) with a different species composition.  All sites were sampled in 2006-2007; monitoring continues at the eruption area site up to the present.  Larval samples (Fig. 3) were collected near P Vent and K Vent using plankton pumps and sediment traps in 2006-2007 to ascertain whether species composition and abundance differed between the sites.  All macrofauna, including juveniles and larvae, were identified to the lowest possible taxonomic group, often to species.  Where species-level identifications were not possible, we implemented barcoding for numerically important groups.

The long-term studies at P Vent showed that species diversity has continued to increase over time since 2006 (Fig 4).  The presence of the pioneer limpet Lepetodrilus tevnianus, which was not detected immediately prior to the eruption, as late as 8 years afterward showed that initial colonists may affect the development of the community through time.  Short-term colonization studies indicated that settlement was different at the three sites.  In particular, we found that the pre-existing community at V Vent affected the species and numbers of animals settling there (Fig. 5) and that this effect was strongest in the Warm zone (typically settled by mussels, ~4-10° C).  Numbers and species composition of larvae arriving at  P Vent differed substantially from those at K Vent.  This may be due to differences in the local species composition or could be affected by transport by currents.

Our results, using a diverse suite of species rather than just large animals visible in photographic surveys, show that succession at these sites continues more than a decade after the original disturbance.  Hydrothermal vents have been generally characterized as being highly resilient.  However, this extended recovery time in an area subject to frequent eruptions suggests that we cannot expect vents to bounce back quickly from anthropogenic disturbance, particularly in regions that do not experience frequent disturbance.

Our results are being used in models of larval connectivity and metacommunity ecology to investigate implications for community dynamics and resilience on regional scales.  Studies of succession at vents, where the disturbance regime, geographic layout, and nutritional source are uniquely coupled with solid earth dynamics, contribute to a broader understanding of succession across terrestrial and marine habitats.  Results from this project were used in the development of the sFDvent global functional trait database for hydrothermal vent species.  Data files from this project have been uploaded to the Biological and Chemical Oceanographic Data Management Office (BCO-DMO), where they are publicly accessible.

This work has contributed to the training of undergraduate and graduate students and post-doctoral investigators, including several belonging to underrepresented minorities.  It is our hope that this will contribute to a diverse and well-educated population of researchers in the fields of biology and earth sciences.

Last Modified: 05/01/2018
Modified by: Lauren S Mullineaux