Adams Diane K.

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Diane K.

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  • Preprint
    Persistent effects of disturbance on larval patterns in the plankton after an eruption on the East Pacific Rise
    ( 2013-07) Mills, Susan W. ; Mullineaux, Lauren S. ; Beaulieu, Stace E. ; Adams, Diane K.
    To predict how benthic communities will respond to disturbance, it is necessary to understand how disturbance affects the planktonic larval supply available to recolonize the area. Deep-sea hydrothermal vent fauna along the East Pacific Rise (EPR) experience frequent local extinctions due to tectonic and magmatic events, but the effects on regional larval abundance and diversity are unknown. We had been monitoring larvae at 9° 50' N on the EPR prior to the 2006 eruption and were able to resume collections shortly afterward. We found that many species that were common before the eruption became significantly less so afterward, whereas a few other species experienced a transient spike in abundance. Surprisingly, overall species richness in the plankton was high 9 mo after the eruption, but then decreased sharply after 1 yr and had not returned to pre-eruption levels after 2 yr. These results suggest that recovery from disturbance may continue to be affected by limited larval supply even several years after a disturbance event. This delay in recovery means that larvae of pioneer species may dominate potential colonists, even after benthic habitats have transitioned to conditions that favor later-successional species. Moreover, the combined effects of natural and anthropogenic disturbance (e.g. mining) would be likely to cause more profound and long-lasting changes than either event alone. Our results indicate that we do not have sufficient data to predict the timing of recovery after disturbance in the deep sea, even in a well-studied vent system.
  • Preprint
    Surface-generated mesoscale eddies transport deep-sea products from hydrothermal vents
    ( 2011-03) Adams, Diane K. ; McGillicuddy, Dennis J. ; Zamudio, Luis ; Thurnherr, Andreas M. ; Liang, Xinfeng ; Rouxel, Olivier J. ; German, Christopher R. ; Mullineaux, Lauren S.
    Atmospheric forcing, which is known to have a strong influence on surface ocean dynamics and production, is typically not considered in studies of the deep sea. Our observations and models demonstrate an unexpected influence of surface-generated mesoscale eddies in the transport of hydrothermal vent efflux and of vent larvae away from the northern East Pacific Rise. Transport by these deep-reaching eddies provides a mechanism for spreading the hydrothermal chemical and heat-flux into the deep-ocean interior and for dispersing propagules hundreds of kilometers between isolated and ephemeral communities. Since the eddies interacting with the East Pacific Rise are formed seasonally and are sensitive to phenomena such as El Niño, they have the potential to introduce seasonal to interannual atmospheric variations into the deep sea.
  • Thesis
    Influence of hydrodynamics on the larval supply to hydrothermal vents on the East Pacific Rise
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2007-06) Adams, Diane K.
    Examination of the scales at which larval supply varies spatially and temporally, and correlation with concurrent physical observations can provide insights into larval transport mechanisms that contribute to structuring marine benthic communities. In order to facilitate field studies, this thesis first provides new morphological and genetic identifications for hydrothermal vent gastropod larvae along the northern East Pacific Rise. Daily and weekly variability in the supply of hydrothermal vent gastropod larvae to two hydrothermal vents, 1.6 km apart on the East Pacific Rise, were quantified concurrently with current velocity observations. The magnitude and temporal pattern of larval supply differed between vent sites, despite their close proximity. A strong correlation between along-axis flow and daily larval supply suggested that larval supply occurred primarily via along-axis transport between local sources 1-2 km apart. However, weekly larval supply appeared to be driven by larger spatial scales through losses associated with cross-axis flows and the passage of mesoscale eddies. Tracer movement within a quasi-geostrophic eddy model was consistent with the observations of decreased larval supply concurrent with an eddy observed via satellite altimetry. The tracer movement also indicated that deep eddy-induced flow could facilitate a long-distance dispersal event, enhancing dispersal between vents 100s km apart.
  • Preprint
    Expanding dispersal studies at hydrothermal vents through species identification of cryptic larval forms
    ( 2010-01) Adams, Diane K. ; Mills, Susan W. ; Shank, Timothy M. ; Mullineaux, Lauren S.
    The rapid identification of hydrothermal vent-endemic larvae to the species level is a key limitation to understanding the dynamic processes that control the abundance and distribution of fauna in such a patchy and ephemeral environment. Many larval forms collected near vents, even those in groups such as gastropods that often form a morphologically distinct larval shell, have not been identified to species. We present a staged approach that combines morphological and molecular identification to optimize the capability, efficiency, and economy of identifying vent gastropod larvae from the northern East Pacific Rise (NEPR). With this approach, 15 new larval forms can be identified to species. A total of 33 of the 41 gastropod species inhabiting the NEPR, and 26 of the 27 gastropod species known to occur specifically in the 9° 50’ N region, can be identified to species. Morphological identification efforts are improved by new protoconch descriptions for Gorgoleptis spiralis, Lepetodrilus pustulosus, Nodopelta subnoda, and Echinopelta fistulosa. Even with these new morphological descriptions, the majority of lepetodrilids and peltospirids require molecular identification. Restriction fragment length polymorphism digests are presented as an economical method for identification of five species of Lepetodrilus and six species of peltospirids. The remaining unidentifiable specimens can be assigned to species by comparison to an expanded database of 18S ribosomal DNA. The broad utility of the staged approach was exemplified by the revelation of species-level variation in daily planktonic samples and the identification and characterization of egg capsules belonging to a conid gastropod Gymnobela sp. A. The improved molecular and morphological capabilities nearly double the number of species amenable to field studies of dispersal and population connectivity.
  • Preprint
    Larvae from afar colonize deep-sea hydrothermal vents after a catastrophic eruption
    ( 2010-01-29) Mullineaux, Lauren S. ; Adams, Diane K. ; Mills, Susan W. ; Beaulieu, Stace E.
    The planktonic larval stage is a critical component of life history in marine benthic species because it confers the ability to disperse, potentially connecting remote populations and leading to colonization of new sites. Larval-mediated connectivity is particularly intriguing in deep-sea hydrothermal vent communities, where the habitat is patchy, transient and often separated by tens or hundreds of kilometers. A recent catastrophic eruption at vents near 9°50’N on the East Pacific Rise created a natural clearance experiment and provided an opportunity to study larval supply in the absence of local source populations. Previous field observations have suggested that established vent populations may retain larvae and be largely self-sustaining. If this hypothesis is correct, the removal of local populations should result in a dramatic change in the flux, and possibly species composition, of settling larvae. Fortuitously, monitoring of larval supply and colonization at the site had been established before the eruption and resumed shortly afterward. We detected a striking change in species composition of larvae and colonists after the eruption, most notably the appearance of the gastropod Ctenopelta porifera, an immigrant from possibly >300 km away, and the disappearance of a suite of species that formerly had been prominent. This switch demonstrates that larval supply can change markedly after removal of local source populations, enabling recolonization via immigrants from distant sites with different species composition. Population connectivity at this site appears to be temporally variable, depending not only on stochasticity in larval supply, but also on the presence of resident populations.
  • Article
    Larval dispersal : vent life in the water column
    (The Oceanography Society, 2012-03) Adams, Diane K. ; Arellano, Shawn M. ; Govenar, Breea
    Visually striking faunal communities of high abundance and biomass cluster around hydrothermal vents, but these animals don't spend all of their lives on the seafloor. Instead, they spend a portion of their lives as tiny larvae in the overlying water column. Dispersal of larvae among vent sites is critical for population maintenance, colonization of new vents, and recolonization of disturbed vents. Historically, studying larvae has been challenging, especially in the deep sea. Advances in the last decade in larval culturing technologies and more integrated, interdisciplinary time-series observations are providing new insights into how hydrothermal vent animals use the water column to maintain their populations across ephemeral and disjunct habitats. Larval physiology and development are often constrained by evolutionary history, resulting in larvae using a diverse set of dispersal strategies to interact with the surrounding currents at different depths. These complex biological and oceanographic interactions translate the reproductive output of adults in vent communities into a dynamic supply of settling larvae from sources near and far.