Underwater mass spectrometry systems can be used for direct in situ detection of volatile organic compounds and dissolved gases in oceans, lakes, rivers and waste-water streams. In this work we describe the design and operation of (1) a linear quadrupole mass filter and (2) a quadrupole ion trap mass spectrometer interfaced, in each case, with a membrane introduction/fluid control system and packaged for underwater operation. These mass spectrometry systems can operate autonomously, or under user control via a wireless rf link. Detection limits for each system were determined in the laboratory using pure solutions. The quadrupole mass filter system provides detection limits in the 1-5 ppb range with an upper mass limit of 100 amu. Its power requirement is approximately 95 Watts. The ion trap system has detection limits well below 1 ppb, an upper mass limit of 650 amu and MS/MS capability. Its power consumption is on the order of 150 Watts. The present membrane limits analysis to non-polar compounds (Ͻ300 amu) with analysis cycles of 5-15 minutes. Deployments of both types of instruments are described, along with a discussion of the challenges associated with in-water mass spectrometry and descriptions of alternative in-water mass spectrometer configurations. (J Am Soc Mass Spectrom 2001, 12, 676 -682 ) © 2001 American Society for Mass Spectrometry S tandard methods for analysis of aqueous systems typically involve collection of samples and delivery to a laboratory for analysis [1]. Inherent in this practice is the possibility of both contamination and loss of analytes, particularly in the case of highly reactive or volatile species. In addition, this type of sampling severely limits both spatial and temporal sampling densities. A particularly important limitation of long collection/analysis cycles is the inability to implement adaptive sampling. Appropriate monitoring of dynamic biogeochemical systems requires rapid sampling adaptations in response to rapidly varying analyte distributions [2]. Intelligent sampling strategies are required to adequately characterize vast bodies of water that influence, and are influenced by, human activities. Since mass spectrometry is arguably the most versatile of chemical sensors, we have undertaken development of in situ mass spectrometry systems capable of real-time, adaptive in-water analyses.Although mass spectrometry has been used in the laboratory for an extremely wide variety of chemical analyses, from precise isotopic ratio measurements [3] to DNA sequencing [4 -6], no single configuration of mass analyzer and sample interface is appropriate for all types of measurements. This is evidenced in recent reviews of field analytical techniques [7] and advances in miniaturization of mass spectrometers [8]. Accordingly, we have chosen a modular approach for development of immersion mass spectrometers. Initially, simpler designs are used to integrate available components, and simultaneously new subsystems are being developed for evolving reconfigurations capable of accessing a w...

Macronutrients and trace metals are incorporated into phytoplankton during growth and regenerated back into the water column when phytoplankton decay, a process that contributes to the distributions of dissolved trace metals and macronutrients in depth profiles. To study this, we incubated mixed Gulf of Mexico phytoplankton assemblages and monocultures of the diatom Pseudo-nitzschia dolorosa and the dinoflagellate Karenia brevis in the dark. Over 6 months, macronutrients (phosphate, silicic acid, nitrate + nitrite, nitrite, ammonium), chlorophyll-a, particulate organic carbon and nitrogen, and prokaryotes were monitored alongside dissolved manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb). Results were compared to depth profiles to evaluate the role of regeneration in trace metal cycling. In contrast to water-column distributions, silicic acid and phosphate were closely coupled in experiments containing diatoms, indicating a shared regeneration pathway. Nitrification and nitrifying prokaryotes were only observed near the end of a subset of the experiments. Of the trace metals, Cd was most tightly coupled with phosphate. Regeneration of Mn was followed by rapid drawdown, consistent with Mn-oxide formation. Iron (Fe), Cu, and Pb typically remained low until Mn was depleted, suggesting either scavenging to Mn-oxides or otherwise delayed regeneration of these elements. Cobalt (Co) and Ni were largely conservative, but behaved like nutrients in the experiment using more offshore water low in Cd and Zn. Although experimental conditions were limited in their representation of the water column, these incubations provide novel insight into macronutrient and trace metal regeneration in the oceans. At the base of the marine food web, phytoplankton require the macronutrients carbon (C), nitrogen (N), and phosphorous (P) to build cellular organic matter, and, for diatoms, silicon (Si) to build frustules (Redfield 1934; Brzezinski 1985). Phytoplankton also assimilate a suite of trace metals into their cells, including manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) (

Identifying spawning sites for broadcast spawning fish species is a key element of delineating critical habitat for managing and regulating marine fisheries. Genetic barcoding has enabled accurate taxonomic identification of individual fish eggs, overcoming limitations of morphological classification techniques. In this study, planktonic fish eggs were collected at 23 stations along the northwestern coast of Cuba and across the Florida Straits to United States waters. A total of 564 fish eggs were successfully identified to 89 taxa within 30 families, with the majority of taxa resolved to species. We provide new spawning information for Luvarus imperialis (Louvar), Bothus lunatus (Plate Fish), Eumegistus illustris (Brilliant Pomfret), and many economically important species. Data from most sites supported previously established patterns of eggs from neritic fish species being found on continental shelves and oceanic species spawning over deeper waters. However, some sites deviated from this pattern, with eggs from reef‐associated fish species detected in the deep waters of the Florida Straits and pelagic species detected in the shallow, continental shelf waters off the coast of northwestern Cuba. Further investigation using satellite imagery revealed the presence of a mesoscale cyclonic eddy that likely entrained neritic fish eggs and transported them into the Florida Straits. The technique of combining DNA‐based fish egg identification with remotely‐sensed hydrodynamics provides an important new tool for assessing the interplay of regional oceanography with fish spawning strategies.

An automated field analysis strategy for aqueous environments is proposed with the use of a mobile robot equipped with an underwater mass spectrometer aided by linked remote numerical models or natural intelligence. Intelligent search strategies were made possible through the use of numerical models, and natural intelligence was in the form of a man in the loop. The field-analysis strategy is useful for local-and wide-area in situ chemical surveying for environmental and economical tasks. The operation of chemoreceptive field underwater robots is demonstrated during two field trials, one using numerical models to aid in characterization of chemical dispersion, and the other discriminating a chemical gradient in the field.

Vibrio natriegens is a naturally occurring marine bacterium that is emerging as a microbiological model system. Here, we describe Aquatic Killer 99 (AQKL99), a novel phage that infects Vibrio natriegens 14048. The genome of the phage is 58,464 bp long, has a GC content of 45.9%, and contains 51 protein-coding genes.

Fish are an important resource worldwide and their management requires a combination of strategies, including the protection of spawning areas. However, the identification of fish early life stages, especially fish eggs, is challenging due to the lack of distinguishing morphological features.

A critical factor in fisheries management is the protection of spawning sites for ecologically and economically important fish species. DNA barcoding (i.e., amplification and sequencing of the mitochondrial cytochrome c oxidase I (COI) gene) of fish eggs has emerged as a powerful technique for identifying spawning sites. However, DNA barcoding of individual fish eggs is time-consuming and expensive. In an attempt to reduce costs and effort for long-term fisheries monitoring programs, here we used DNA metabarcoding, in which DNA is extracted and amplified from a composited sample containing all the fish eggs collected at a given site, to identify fish eggs from 49 stations on the West Florida Shelf. A total of 37 taxa were recovered from 4,719 fish eggs. Egg distributions on the West Florida Shelf corresponded with the known habitat types occupied by these taxa, which included burrower, coastal pelagic, epipelagic, mesopelagic, demersal, deep demersal, commensal, and reef-associated taxa. Metabarcoding of fish eggs was faster and far less expensive than barcoding individual eggs; however, this method cannot provide absolute taxon proportions due to variable copy numbers of mitochondrial DNA in different taxa, different numbers of cells within eggs depending on developmental stage, and PCR amplification biases. In addition, some samples yielded sequences from more taxa than the number of eggs present, demonstrating the presence of contaminating DNA and requiring the application of a threshold proportion of sequences required for counting a taxon as present. Finally, we review the advantages and disadvantages of using metabarcoding vs. individual fish egg barcoding for long-term monitoring programs.

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