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"Disappearing Red Shrimp" feature in 12/20/10 edition of Science Nation, a science video series from the National Science Foundation (NSF)

High Def (HD) underwater video of anchialine ecosystem at Pohue Bay, Hawaii (from 7/28/2010)

(HD videos require Quicktime plug-in as well as high speed internet connection and modest computer for reasonable viewing)

Anchialine environments are coastal land-locked bodies of mixohaline water exhibiting tidal fluctuations due to their simultaneous subterranean connections to the ocean and groundwater aquifer. These environments are home to often regionally endemic species that define these habitats as a unique ecosystem. Anchialine ecosystems are extremely rare worldwide and are increasingly becoming endangered by anthropogenic pressures such as urbanization and invasive species introductions. This is particularly true in the Hawaiian Islands, which has the only natural anchialine environments in the US and the single largest concentration of them on the planet. Current estimates suggest that >90% of the islands' historically known anchialine environments have already been lost or degraded, which potentially makes this one of Hawaii's most threatened ecosystems. Unfortunately, this ecosystem has been relatively unexplored and we risk losing the opportunity of documenting the biodiversity contained within it in the near future.

While microbes are essential to the community structure and function of anchialine ecosystems, their identities and ecology have so far been poorly characterized both in Hawaii and elsewhere. In this context, the Systematic Biology and Biodiversity Inventories Program within the Division of Environmental Biology at the National Science Foundation (NSF) has generously funded The Santos Lab for the next three (3) years to describe and document the taxonomic diversity and relative abundances of Archaea, Bacteria and micro-Eukarya populations from Hawaii's threatened anchialine environments. Specifically, high-throughput microbiome profiling by Illumina sequencing of 16S/18S-rDNA "tags" will be utilized in conjunction with environmental data to: 1) identify factors influencing microbial community composition across space; 2) investigate temporal dynamics in community composition, and; 3) quantify changes in community composition of habitats impacted by environmental perturbation. This project will also establish a Hawaiian Anchialine Microbial (HAM) repository in conjunction with Ocean Genome Legacy to maintain future access to these microbial communities in the face of continuing habitat loss and their potential for containing taxa of basic research and/or applied scientific value. Overall, the proposed work will further our limited understanding of microbial ecology in anchialine environments as well as develop a foundation for testing specific hypotheses on the ecological, biogeochemical, and metabolic roles microbes play in this vanishing ecosystem. Additional information on the project can be found on it's NSF Award Page (NSF-DEB #0949855).

Prior to our NSF-funded anchialine microbial ecology project, The Santos Lab had previously investigated the genetic structure and population history of the most common species found in Hawaii's anchialine ecosystem, the endemic Hawaiian atyid shrimp Halocaridina rubra.  Surveys of populations from 34 sites on the islands of Hawaii, Maui, and Oahu revealed 13 distinct genetic groups belonging to eight divergent lineages. In general, a Halocaridina genetic group or lineage was restricted to a particular region of a single Hawaiian Island, with no individuals being exchanged between them. This pattern stems from a combination of intrinsic organismal properties such as large egg size, abbreviated development, restricted larval habitat and larval feeding mode, and extrinsic obstacles to gene flow in the form of a marine barrier and geologic features that compartmentalize the islands' aquifers. The phylogeographic structuring on and between islands suggests evolutionary diversification in Halocaridina is driven by population fragmentation, isolation, and subsequent diversification in the aquifers of the Hawaiian Islands. Calibration of cytochrome oxidase subunit I sequence divergence between sister Halocaridina lineages to the geologic age of Kilauea volcano on Hawaii implies diversification in the genus is proceeding at a short-term rate of 20% per million years. These studies bring novel insight into the natural history of Halocaridina and have important implications for the future management of the species and their habitats. This project is part of a collaborative effort to better understand Hawaii's anchialine habitats and their organisms, with participation from the State of Hawaii Division of Aquatic Resources, US Fish and Wildlife Service and National Park Service.

Lastly, lab member David A. Weese has expanded The Santos Lab's population genetic studies of anchialine crustaceans to the Ryukyu Islands in Japan through generous funding in 2009 from the NSF's East Asia and Pacific Summer Institutes (EAPSI) Program (NSF-OISE #0913667) and hosting by Drs. Yoshihisa Fujita and Michio Hidaka of the University of the Ryukyus. Manuscripts from these studies are forthcoming.


Hawaii anchialine research feature in "Where in The World? North America" series by MO BIO Laboratories, INC.


Video of "Anchialine Pools: Uncovering the Hidden Secrets" presentation at Hawai'i Volcanoes National Park website.


Maps depicting the distribution of Halocaridina rubra lineages across the Hawaiian Islands (Current as of: April 2009). Maps of Hawaii, Maui and Oahu. Detailed map of Oahu.


Read a February 18, 2009 blog by Jan TenBruggencate of Raising Islands on Weese & Santos (2009) "Genetic identification of source populations for an aquarium-traded invertebrate" from the journal Animal Conservation, which documents the likely source populations of Halocaridina rubra from the aquarium trade.


Read a April 4, 2008 blog by Jan TenBruggencate of Raising Islands on a new anchialine shrimp fact sheet released by the U.S. Fish and Wildlife Service and the State of Hawaii Department of Land and Natural Resources Division of Aquatic Resources.


Anchialine shrimp fact sheet from the U.S. Fish and Wildlife Service and the State of Hawaii Department of Land and Natural Resources Division of Aquatic Resources.


Read a December 17, 2007 blog by Jan TenBruggencate of Raising Islands highlighting this research project.


Read an article by Auburn graduate and nationally syndicated columnist Rheta Grimsley Johnson about her travel experience with Halocaridina rubra.


Read the June 12, 2006 article by Jan TenBruggencate of the Honolulu Advertiser about this research project.


Photo gallery of anchialine habitats, field collections and organisms from Hawaii, Maui and Oahu (2004 - 2009).


View/download the complete mitochondrial genome sequence of Halocaridina rubra (View the genome) (Download the genome as a GenBank format text file)


HALO-BLAST: Search the Halocaridina rubra transcriptome databases.

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