Browsing by Author "Northup, Diana E."
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- Cave microbial community composition in oceanic islands : disentangling the effect of different colored mats in diversity patterns of Azorean lava cavesPublication . Riquelme, Cristina; Rigal, François; Hathaway, Jennifer J. Marshall; Northup, Diana E.; Spilde, Michael N.; Borges, Paulo A. V.; Gabriel, Rosalina; Amorim, Isabel R.; Dapkevicius, Maria de Lurdes N. E.Processes determining diversity and composition of bacterial communities in island volcanic caves are still poorly understood. Here, we characterized colored microbial mats in 14 volcanic caves from two oceanic islands of the Azores using 16S rRNA gene sequences. Factors determining community diversity (α) and composition (β) were explored, namely colored mats, caves and islands, as well as environmental and chemical characteristics of caves. Additive partitioning of diversity using OTU occurrence showed a greater influence of β-diversity between islands and caves that may relate to differences in rare OTUs (singletons and doubletons) across scales. In contrast, Shannon diversity partitioning revealed the importance of the lowest hierarchical level (α diversity, colored mat), suggesting a dominance of cosmopolitan OTUs (>1%) in most samples. Cosmopolitan OTUs included members involved in nitrogen cycling, supporting the importance of this process in Azorean caves. Environmental and chemical conditions in caves did not show any significant relationship to OTU diversity and composition. The absence of clear differences between mat colors and across scales may be explained by (1) the geological youth of the cave system (cave communities have not had enough time to diverge) or/and (2) community convergence, as the result of selection pressure in extreme environments.
- Comparison of Bacterial Diversity in Azorean and Hawai'ian Lava Cave Microbial MatsPublication . Hathaway, Jennifer J. Marshall; Garcia, Matthew G.; Balasch, Monica Moya; Spilde, Michael N.; Stone, Fred D.; Dapkevicius, Maria de Lurdes N. E.; Amorim, Isabel R.; Gabriel, Rosalina; Borges, Paulo A. V.; Northup, Diana E.Worldwide, lava caves host colorful microbial mats. However, little is known about the diversity of these microorganisms, or what role they may play in the subsurface ecosystem. White and yellow microbial mats were collected from four lava caves each on the Azorean island of Terceira and the Big Island of Hawai’i, to compare the bacterial diversity found in lava caves from two widely separated archipelagos in two different oceans at different latitudes. Scanning electron microscopy of mat samples showed striking similarities between Terceira and Hawai’ian microbial morphologies. 16S rRNA gene clone libraries were constructed to determine the diversity within these lava caves. Fifteen bacterial phyla were found across the samples, with more Actinobacteria clones in Hawai’ian communities and greater numbers of Acidobacteria clones in Terceira communities. Bacterial diversity in the subsurface was correlated with a set of factors. Geographical location was the major contributor to differences in community composition (at the OTU level), together with differences in the amounts of organic carbon, nitrogen and copper available in the lava rock that forms the cave. These results reveal, for the first time, the similarity among the extensive bacterial diversity found in lava caves in two geographically separate locations and contribute to the current debate on the nature of microbial biogeography.
- Fundamental research questions in subterranean biologyPublication . Mammola, Stefano; Amorim, Isabel R.; Bichuette, Maria E.; Borges, Paulo A. V.; Cheeptham, Naowarat; Cooper, Steven J. B.; Culver, David C.; Deharveng, Louis; Eme, David; Ferreira, Rodrigo Lopes; Fišer, Cene; Fišer, Žiga; Fong, Daniel W.; Griebler, Christian; Jeffery, William R.; Jugovic, Jure; Kowalko, Johanna E.; Lilley, Thomas M.; Malard, Florian; Manenti, Raoul; Martínez, Alejandro; Meierhofer, Melissa B.; Niemiller, Matthew L.; Northup, Diana E.; Pellegrini, Thais G.; Pipan, Tanja; Protas, Meredith; Reboleira, Ana Sofia; Venarsky, Michael P.; Wynne, J. Judson; Zagmajster, Maja; Cardoso, PedroFive decades ago, a landmark paper in Science titled The Cave Environment heralded caves as ideal natural experimental laboratories in which to develop and address general questions in geology, ecology, biogeography, and evolutionary biology. Although the 'caves as laboratory' paradigm has since been advocated by subterranean biologists, there are few examples of studies that successfully translated their results into general principles. The contemporary era of big data, modelling tools, and revolutionary advances in genetics and (meta)genomics provides an opportunity to revisit unresolved questions and challenges, as well as examine promising new avenues of research in subterranean biology. Accordingly, we have developed a roadmap to guide future research endeavours in subterranean biology by adapting a well-established methodology of 'horizon scanning' to identify the highest priority research questions across six subject areas. Based on the expert opinion of 30 scientists from around the globe with complementary expertise and of different academic ages, we assembled an initial list of 258 fundamental questions concentrating on macroecology and microbial ecology, adaptation, evolution, and conservation. Subsequently, through online surveys, 130 subterranean biologists with various backgrounds assisted us in reducing our list to 50 top-priority questions. These research questions are broad in scope and ready to be addressed in the next decade. We believe this exercise will stimulate research towards a deeper understanding of subterranean biology and foster hypothesis-driven studies likely to resonate broadly from the traditional boundaries of this field.