Autonomous Reef Monitoring Structures (ARMS) Overview

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Autonomous Reef Monitoring Structures (ARMS) are small, long-term collecting devices designed to mimic the structural complexity of a coral reef and attract colonizing invertebrates. Developed by CRED in partnership with the Census of Marine Life (CoML), Census of Coral Reef Ecosystems (CReefs), ARMS were created to assess and explain the diversity, distribution, abundance, and community structure of the cryptofauna community (the most diverse community of organisms on a coral reef) on a global scale.

An ARMS unit is essentially a tier of nine 23 cm x 23 cm gray, Type I PVC plates stacked in an alternating series of open and obstructed formats attached to a 35 cm x 45 cm base plate. The entire structure is affixed to the sea floor and remains on the benthos for 1-3 years during which time it becomes colonized with marine organisms.

ARMS provide a systematic, consistent, and comparable method to monitor cryptofauna diversity.

An ARMS sampling unit before deployment
An ARMS sampling unit before deployment
Newly deployed ARMS
Newly deployed ARMS
ARMS recruitment after two years
ARMS recruitment after two years
An encapsulated ARMS unit for retrieval
An encapsulated ARMS unit for retrieval

Upon recovery, the ARMS unit's 8 layer tier is encapsulated within a mesh-lined container to prevent the escape of motile (moving) organisms. The units are disassembled plate by plate, with both sides photo-documented for spatial analyses of sessile (non-moving) organism coverage. 2 mm, 500 µm, and 100 µm geologic sieves are used to obtain three motile size fractions. The largest fraction (> 2 mm) is sorted into morphtaxonomic groups and can be processed via standard voucher-based molecular barcoding techniques. The two smaller motile fractions are processed via metabarcoding next-generation sequencing techniques. The sessile organisms are scraped off the plates, homogenized, and preserved for metabarcoding next-generation sequencing.

Examples of sessile and motile organisms collected from an ARMS unit.

A typical ARMS unit yields hundreds of specimens of motile and sessile invertebrates from many tens of species thereby making them an ideal platform to examine biodiversity in a standard, replicable, and systematic manner. Preliminary estimates of the number of unique DNA sequences (i.e. species) from the metagenomic metabarcoding analyses is >1000 for an individual ARMS unit on a coral reef. They improve our ability to monitor, measure, and relate the cryptofauna community with ecosystem processes and provide baseline data across large biogeographic, environmental, human impact, and management protection gradients. They have been adopted as a key biodiversity assessment tool by NOAA's National Coral Reef Monitoring Program' (NCRMP) and Ocean Acidification Program's climate monitoring stations in the Pacific. They are also a central component of the Smithsonian's Global Marine Biodiversity Project.

The ARMS Project has expanded on a global scale

Locations of current ARMS deployments
Locations of current ARMS deployments

ARMS have been deployed throughout the Pacific, Indian, and Atlantic Oceans

  • 2006-2008 — Original desgin and testing of ARMS prototypes. The first ARMS units were deployed at French Frigate Shoals during the CReefs research cruise
  • 2008-present — CRED incorporated ARMS into their Pacific Reef Assessment and Monitoring Program (Pacific RAMP) research cruises to:
    • American Samoa
    • Northwestern Hawaiian Islands
    • Main Hawaiian lslands
    • Guam
    • The Commonwealth of the Northern Mariana Islands (CNMI)
    • Pacific Remote Island Areas
  • 2007-2009 — CReefs Australia deployed ARMS at Lizard and Heron Islands (GBR) and Ningaloo Reef
  • 2009 — CRED collaborated with partners on expansion to the following locations:
    • Western Indian Ocean: Reunion, Europa, and Glorieuses Islands
    • Moorea, French Polynesia
    • Florida (Indian River Lagoon)
    • Papua New Guinea (Kimbe Bay)
    • Brazil (Albrohos)
  • 2010 — CRED collaborated with partners on expansion to the following locations:
  • 2012 — CRED collaborated with partners on expansion to the following locations:
    • Philippines - Verde Island Passage and Tubbataha Reefs
    • Dry Tortugas with NOAA's Florida Keys National Marine Sanctuary
    • Florida Keys with NOAA's Florida Keys National Marine Sanctuary
    • Timor Leste with U.S. Agency for International Development (USAID) and Conservation International
    • Puget Sound, Washington with Northwest Fisheries Science Center
    • Chagos Archipelago with James Cook University
  • 2012 — Smithsonian Institution expanded to the following locations:
    • Belize
    • Jordon
    • Florida (Indian River)
    • Chesapeake Bay (Washapreague)
    • Panama (Bocas)
    • Taiwan
    • Curacao
  • 2012 — Australian Institute of Marine Science deployed ARMS along CO2 vents in Papua New Guinea
  • 2012 — CRED collaborated with the European Union's DEVOTES (DEVelopment Of innovative Tools for understanding marine biodiversity and assessing good Environmental Status) Project to expand ARMS to the four regional European Seas
  • 2012 — Recovered ARMS from Kimbe Bay, Papua New Guinea
  • 2012 — Smithsonian Institution deployed ARMS in Saudi Arabia
  • 2013 — ARMS were incorporated into the NOAA National Coral Reef Monitoring Program's and Ocean and Acidification Program's climate and ocean change monitoring stations
  • 2013-2017 — CRED is collaborating with University of California, Los Angeles (UCLA), Smithsonian Institution, Moss Landing Marine Laboratories, and San Diego State University (SDSU) through a National Science Foundation PIRE (Partnerships for International Research and Education) grant to deploy ARMS throughout Indonesia
  • 2014 — ARMS recovered from 8 sites on north coast of Timor Leste

The ARMS Project is Multi-Institutional

DEVOTES Project logo
Florida Museum of Natural History logo
Australian Institute of Marine Science logo
Joint Institute for Marine and Atmospheric Research logo
Moss Landing Marine Laboratories
National Oceanic and Atmospheric Administration logo Natural History Museum of Los Angeles County logo
University of California, Los Angeles logo
San Diego State University logo
Smithsonian Institution