Autonomous Reef Monitoring System (ARMS) in a central California kelp forest
- Jonathan Geller
Moss Landing Marine Laboratories, California State University
- Stephen Palumbi
- Steve Lonhart
Monterey Bay National Marine Sanctuary
- Steve Litvin
This project will assess both marine biodiversity and bioinvasions using a variety of genetic methods, including DNA barcoding and metagenomic analyses of benthic communities, in which bulk DNA from entire assemblages are extracted and sequenced by Next Generation Sequencing technology. The Geller lab has installed an Ion Torrent Personal Genome Machine at MLML and now has the ability to run analyses in-house at MLML.
Settling modules called Autonomous Reef Monitoring System (ARMS) are deployed, colonized by biota, retrieved and analyzed. ARMS are a systematic sampling tool to comparatively assess spatial patterns and monitor temporal trends in the diversity of poorly-known cryptic biota on reefs worldwide. Mimicking the structural complexity of benthic habitats to attract colonizing sessile and motile organisms, ARMS have been deployed in shallow (12-15 m) reef habitats across biogeographic, oceanographic, and human impact gradients in the Pacific, Atlantic, and Indian Oceans, almost exclusively in tropical and sub-tropical systems. To our knowledge there have been very few attempts to use this method in temperate waters.
Dr. Geller is working with Hopkins Marine Station, MBARI, MBNMS and UCSC to create a Monterey Bay Genomics Observatory (tentatively MB-GO), and with the Western Association of Marine Laboratories to create a network of GOs. Coupled with the Genomics Standards Consortium, the nascent MB-GO can link to WAML-GO and to the growing global network of observatories.
Summary to DateOn May 9, 2013 staff from Hopkins Marine Station (Dr. Steve Litvin and Dr. Kerry Nickols) assisted SIMoN staff with deployment of nine ARMS in the kelp forest adjacent to HMS. Three modules each were placed in locations on the inner edge, middle, and outer edge of the eastern kelp forest just off of Agassiz Beach. The ARMS are co-located with a suite of sampling instruments that Dr. Nickols is using to sample larvae. In addition, ADCPs and other instruments are in place to characterize nearshore water movement into and through the kelp bed. The data from this cluster of instruments will be used to describe fine-scale water movements and their entrained larvae, as well as larval settlement patterns in the kelp forest community.
During the week of November 18th, 2013, all 9 ARMS were retrieved. The ARMS soaked for six months, and none of them were lost in spite of some early winter swell that swept through the area. ARMS were covered with 100 micron mesh in a rigid frame and brought to the surface by divers. All organisms were collected by Dr. Jon Geller (MLML) and his graduate students while working at HMS. These included organisms that either settled onto the PVC plates or settled/crawled into the mesh layer matrix near the top of the ARMS.
Genetic analyses at the Geller lab in Moss Landing will determine which species were present. This process can take a couple of months, and we hope to have results by spring.
- The ARMS were deployed in May 2013 and retrieved during the week of November 18th, 2013.
- Barnacles (possibly Balanus crenatus) were very dense on the three replicate ARMS located on the outer edge of the kelp bed, whereas the ARMS from the middle and inner portions of the kelp bed had fewer barnacles.
- The ARMS served as excellent habitat for red Pacific octopus, and each one had at least 5 individuals in them. There were also several instances of the octopus laying eggs in or under the ARMS.
- Dispersal & Recruitment
Study MethodsScience divers deployed the ARMS from small boats launched from the beach at Hopkins Marine Station (HMS). ARMS consist of 15 separate, 30 by 30 cm plastic plates stacked on top of one another with a 1 cm gap between each plate. These are attached to a larger plastic baseplate (~40 by 40 cm) and look like a stack of dishes. The ARMS were fixed in place using earth anchors in sandy areas, and the ARMS will be tied to the earth anchors with cable ties. Earth anchors are screwed into the sand, usually to a depth of at least 40 cm.
ARMS will remain in the water for 2-6 months. During this soak time, divers will periodically visit the ARMS to ensure they are still in place, to take photos, and service them as needed. Once the soak period is over, the ARMS and earth anchors/cement blocks will be removed and re-used in the 2014 deployment phase.
Figures and Images
Figure 1. Top layers of the Autonomous Reef Monitoring System (ARMS). Under the top plate is a layer of plastic mesh that provides small but mobile invertebrates with a spatially complex habitat. This is how the ARMS appear when first deployed, before any organisms settle onto the PVC surface or into the mesh matrix.
Figure 2. Each of the stacked PVC tiles serves as a settling plate for invertebrates and algae that would otherwise recruit onto the rocky reef itself.
Figure 3. Although each ARMS unit is heavy (about 10 lbs), earth anchors were screwed into the sand through holes in the corner of the baseplate. Early summer swell conditions in Monterey Bay are mild.
Figure 4. After soaking for several months, ARMS are recovered by divers, placed in mesh bags, then brought to the surface and hauled into a small boat. The ARMS then head to a lab at the Hopkins Marine Station for processing. Each of the ARMS is disassembled separately and all mobile organisms (e.g., crabs, snails, slugs) removed and curated. Then the individual plates, which are covered with fouling organisms (e.g., barnacles, scallops, worms), are photographed before being scraped clean.
Figure 5. Unknown bryozoan (aka moss animal) that was growing one one of the PVC plates inside the ARMS. Each opening represents an individual member of the colony, akin to a coral colony.
Figure 6. Unknown annelid worm that was removed from one of the ARMS settling plates. The elongate, thread-like tentacles are used for feeding, trapping small organic particles that drift in the water.