Kaiser
Carl L.
Kaiser
Carl L.
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ArticleSyPRID sampler : a large-volume, high-resolution, autonomous, deep-ocean precision plankton sampling system(Elsevier, 2016-05-19) Billings, Andrew F. ; Kaiser, Carl ; Young, Craig M. ; Hiebert, Laurel S. ; Cole, Eli ; Wagner, Jamie K.S. ; Van Dover, CindyThe current standard for large-volume (thousands of cubic meters) zooplankton sampling in the deep sea is the MOCNESS, a system of multiple opening–closing nets, typically lowered to within 50 m of the seabed and towed obliquely to the surface to obtain low-spatial-resolution samples that integrate across 10 s of meters of water depth. The SyPRID (Sentry Precision Robotic Impeller Driven) sampler is an innovative, deep-rated (6000 m) plankton sampler that partners with the Sentry Autonomous Underwater Vehicle (AUV) to obtain paired, large-volume plankton samples at specified depths and survey lines to within 1.5 m of the seabed and with simultaneous collection of sensor data. SyPRID uses a perforated Ultra-High-Molecular-Weight (UHMW) plastic tube to support a fine mesh net within an outer carbon composite tube (tube-within-a-tube design), with an axial flow pump located aft of the capture filter. The pump facilitates flow through the system and reduces or possibly eliminates the bow wave at the mouth opening. The cod end, a hollow truncated cone, is also made of UHMW plastic and includes a collection volume designed to provide an area where zooplankton can collect, out of the high flow region. SyPRID attaches as a saddle-pack to the Sentry vehicle. Sentry itself is configured with a flight control system that enables autonomous survey paths to low altitudes. In its verification deployment at the Blake Ridge Seep (2160 m) on the US Atlantic Margin, SyPRID was operated for 6 h at an altitude of 5 m. It recovered plankton samples, including delicate living larvae, from the near-bottom stratum that is seldom sampled by a typical MOCNESS tow. The prototype SyPRID and its next generations will enable studies of plankton or other particulate distributions associated with localized physico-chemical strata in the water column or above patchy habitats on the seafloor.
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ArticleOcean Dumping of Containerized DDT Waste Was a Sloppy Process(American Chemical Society, 2019-03-04) Kivenson, Veronika ; Lemkau, Karin L. ; Pizarro, Oscar ; Yoerger, Dana R. ; Kaiser, Carl ; Nelson, Robert K. ; Carmichael, Catherine A. ; Paul, Blair G. ; Reddy, Christopher M. ; Valentine, David L.Industrial-scale dumping of organic waste to the deep ocean was once common practice, leaving a legacy of chemical pollution for which a paucity of information exists. Using a nested approach with autonomous and remotely operated underwater vehicles, a dumpsite offshore California was surveyed and sampled. Discarded waste containers littered the site and structured the suboxic benthic environment. Dichlorodiphenyltrichloroethane (DDT) was reportedly dumped in the area, and sediment analysis revealed substantial variability in concentrations of p,p-DDT and its analogs, with a peak concentration of 257 μg g–1, ∼40 times greater than the highest level of surface sediment contamination at the nearby DDT Superfund site. The occurrence of a conspicuous hydrocarbon mixture suggests that multiple petroleum distillates, potentially used in DDT manufacture, contributed to the waste stream. Application of a two end-member mixing model with DDTs and polychlorinated biphenyls enabled source differentiation between shelf discharge versus containerized waste. Ocean dumping was found to be the major source of DDT to more than 3000 km2 of the region’s deep seafloor. These results reveal that ocean dumping of containerized DDT waste was inherently sloppy, with the contents readily breaching containment and leading to regional scale contamination of the deep benthos.
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ArticleSeascape ecology in the vicinity of a Blake Ridge cold seep(Frontiers Media, 2023-11-05) Johnson, Kellie ; Taylor, Avery ; Socha, Annika ; Barkyoumb, Ellie ; Nakamura, Koichi ; Kaiser, Carl L. ; German, Christopher R. ; Yoerger, Dana R. ; Lee Van Dover, CindySystematic surveys of the distribution of epibenthic megafaunal species relative to one another and to environmental variables in the deep sea can lead to inferences and testable hypotheses regarding factors that influence their distributions. Here we use a seascape approach to provide insight into the character and spatial extent of the influence of a chemosynthetic seep on the distribution of epibenthic megafauna and the nature of transition zones (ecotones). Faunal distributions were determined from georeferenced images of the seabed collected during a systematic survey (~ 400 m x 400 m) by the Autonomous Underwater Vehicle Sentry in the vicinity of a newly discovered methane bubble plume on the Blake Ridge Diapir. The survey area was found to include both seep and non-seep habitats. The sphere of influence of seep productivity on the surrounding benthic megafaunal assemblage was limited—on the order of 10’s of meters—based on ecotone analysis. Small but detectable redox anomalies in the water column (5 m above bottom) in the study area occurred on a similar horizontal scale. Distributions of background megafaunal taxa were non-random for many morphotypes and included both positive and negative associations between morphotypes and the seep habitat. Subtle variations in depth (<6 m) correlated with distributions of seep-associated vesicomyid clams, which occupy shallow depressions in the seabed. The seep habitat itself, comprising a patchy mosaic of megafaunal sub-communities (e.g., clam bed, mussel bed, background soft-sediment bathyal taxa) and transition zones, was at least as diverse as the surrounding non-seep habitat and contributes seep endemic morphotypes to regional biodiversity. While seep productivity may support prey fields for deep-diving beaked whales, any relationship between the seeps and whale feeding areas remains intriguing speculation. Like many other regions of the deep sea, Blake Ridge South has accumulated marine litter, including litter likely originating from scientific endeavors. The suite of observations and analyses deployed here underscore the importance of seep habitats in enriching regional biodiversity, provide a glimpse of the non-random complexity of species distributions from a seascape perspective, and establish ecological baselines against which future studies may measure natural and anthropogenic changes in the seascape.