Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2009. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 149-162). / Trichodesmium is a colonial, N2-fixing cyanobacterium found in tropical oceans. Species of Trichodesmium are genetically similar but several species exist together in the same waters. In order to coexist, Trichodesmium spp. may occupy different niche spaces through differential utilization of resources such as nutrients and light, and through responses to physical characteristics such as temperature and turbulence. To investigate niche differentiation in Trichodesmium, I characterized cultured strains of Trichodesmium, identified and enumerated Trichodesmium clades in the field, and investigated P stress and N2 fixation in field populations. Species of Trichodesmium grouped into two clades based on sequences from 16S rDNA, the internal transcribed spacer (ITS), and the heterocyst differentiation gene hetR. Clade I contained Trichodesmium erythraeum and Trichodesmium contortum, and clade II contained Trichodesmium thiebautii, Trichodesmium tenue, Trichodesmium hildebrandtii, and Trichodesmium pelagicum. Each clade was morphologically diverse, but species within each clade had similar pigmentation. I developed a quantitative polymerase chain reaction (qPCR) method to distinguish between these two clades. In field populations of the Atlantic and Pacific Oceans, the qPCR method revealed that clade II Trichodesmium spp. were more prominent than clade I in the open ocean. Concentrations of Trichodesmium did not correlate with nutrient concentrations, but clade I had wider temperature and depth distributions than clade II. / (cont.) Temperature and light are physical characteristics that may define niche spaces for species of Trichodesmium. Clade I and II concentrations correlated with each other in the Pacific but not in the Atlantic, indicating that the two clades were limited by the same factors in the Pacific while different factors were limiting the abundance of the two clades in the Atlantic. Trichodesmium populations in the North Atlantic were more P stressed and had higher N2 fixation rates than populations in the western Pacific. While nutrient concentrations didn't directly correlate with Trichodesmium concentrations, the contrasting nutrient regimes found in the Atlantic and Pacific Oceans might influence distributions of the two clades differently. Unraveling the differences among species of Trichodesmium begins to explain their coexistence and enables us to understand factors controlling global N2 fixation. / by Annette Michelle Hynes. / Ph.D.

Thesis: Ph. D., Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Department of Civil and Environmental Engineering; and the Woods Hole Oceanographic Institution), 2014. / Cataloged from PDF version of thesis. / Includes bibliographical references. / Viral predation on bacteria in the ocean liberates carbon from the particulate fraction, where it is accessible to higher trophic levels, and redirects it to the dissolved fraction, where it supports microbial growth. Although viruses are highly abundant in the ocean little is known about how their interactions with bacteria are structured. This challenge arises because the diversity of both bacteria and viruses is exceedingly high and interactions between them are mediated by specific molecular interactions. This thesis uses heterotrophic bacteria of the genus Vibrio as a model to quantify virus-host interactions in light of host population structure and ecology. The methods developed in this thesis include streamlining of standard bacteriophage protocols, such as the agar overlay, and facilitate higher throughput in the isolation and characterization of novel environmental virus-host systems. Here, >1300 newly isolated Vibrio are assayed for infection by viral predators and susceptibility is found to be common, though total concentrations of predators are highly skewed, with most present at low abundance. The largest phylogenetically-resolved host range cross test available to date is conducted, using 260 viruses and 277 bacterial strains, and highly-specific viruses are found to be prevalent, with nearly half infecting only a single host in the panel. Observations of blocks of multiple viruses with nearly identical infection profiles infecting sets of highly-similar hosts suggest that increases in abundance of particular lineages of bacteria may be important in supporting the replication of highly specific viruses. The identification of highly similar virus genomes deriving from different sampling time points also suggests that interactions for some groups of viruses and hosts may be stable and persisting. Genome sequencing reveals that members of the largest broad host-range viral group recovered in the collection have sequence homology to non-tailed viruses, which have been shown to be dominant in the surface oceans but are underrepresented in culture collections. By integrating host population structure with sequencing of over 250 viral genomes it is found that viral groups are genomically cohesive and that closely-related and co-occurring populations of bacteria are subject to distinct regimes of viral predation. / by Anne Kathryn Marie Kauffman. / Ph. D.

Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2005. / Includes bibliographical references (p. 157-171). / Bacteriophage have been proposed to be the most abundant organisms on the planet, at an estimated 10³¹ particles globally (Hendrix et al., 1999). The majority of bacteriophage isolates (96%) are double-stranded DNA tailed phages (Caudovirales). These phages possess a distinctive icosehedral head, with a protein tail structure protruding from a single vertex. This organelle determines host specificity and provides the mechanism of passage of the phage genome into the host cell. Phages infecting differing microbial hosts may have access to a global pool of genes, albeit at different levels. Marine cyanobacteria of the genera Prochlorococcus and Synechococcus are numerically dominant photosynthetic cells in the large oligotrophic gyres of the open oceans, and contribute an estimated 30% to the oceanic photosynthetic budget. Cyanophages have been isolated which propagate on many strains of Synechococcus and Prochlorococcus. Cyanophages can effect community structure and succession through lytic infection of their hosts, and have implications in lateral gene transfer, mediated through lysogeny, mixed infections, pseudolysogeny, and transduction. / (cont.) The broad host ranges (between genera) observed in some phages indicates that lateral gene transfer is not confined to cells of the same strain. These phage/host interactions begin by host recognition by the tail of the infecting phage. Few studies have examined the structural proteins of cyanophage, partially due to the lack of a robust protocol for the growth and purification of phage particles. Cyanophage Syn5 is a short-tailed phage isolated from the Sargasso Sea by Waterbury and Valois (1993) which infects Synechococcus strain WH8109. Methods of growing the host cells and the phage, and concentrating the phage by PEG precipitation were developed. These methods led to highly concentrated purified phage stocks, to titers of 1012 particles/ml. Preliminary characterization of the growth of Syn5 gave a burst size of approximately 30 phage/cell and a lytic period of approximately 10 hours when inoculated into exponentially growing host cells acclimated to a temperature of 26⁰C and a light intensity of 50[mu]E m⁻² s⁻¹. Isolation of the phage nucleic acid yielded dsDNA molecules of approximately 40kb. The Syn5 particles were comprised of twelve structural proteins, as determined by SDS-PAGE. / (cont.) The most intense band on the gel was assigned to the capsid protein of Syn5 ([approx.] 35kDa). However, it was not possible to distinguish putative tail proteins via this method. Purified Syn5 particles were sent to the Pittsburgh Bacteriophage Institute for genome sequencing. The completed Syn5 genome was 46,214 bp long with a 237bp terminal repeat. Annotation of the completed Syn5 genome identified 61 putative ORFs, and revealed that Syn5 appeared closely related to the enteric phage T7 and cyanophages P-SSP7 and P60, as determined by gene similarity and synteny, although the genome was [approx.] 10kb longer than T7. Syn5 appeared to possess a more extensive DNA replisome that T7, containing copies of genes that encoded proteins of known T7 host co-factors, such as thioredoxin, utilized by the T7 DNAP. Several large ORFs were identified between the gene encoding the putative tail fiber and the gene encoding the putative terminase. These ORFs encoded proteins similar to some fibrous sequences within the NCBI non- redundant (nr) gene sequence database as of March, 2005; but had unknown functions within the phage. Unlike other recently sequenced cyanophages, SynS did not contain any photosynthetic genes. / (cont.) The structural proteins of SynS, as visualized by SDS-PAGE, were characterized by mass-spectroscopy and N-terminal sequencing. This allowed the assignment of sequences to putative ORFs within the Syn5 genome. The Syn5 particle was comprised of eleven discreet protein chains of molecular weight 152kDa, 139kDa, 99kDa, 90kDa, 66kDa, 60kDa, 47kDa, 35kDa, 22kDa, 21kDa, and 16kDa. The identified proteins included the portal, capsid, two tail tube proteins, and three internal virion proteins. Each of the genes encoding these proteins were found in the same gene order in the Syn5 genome as the corresponding genes were ordered in the T7 genome. There were three unidentifiable proteins within the particle (66kDa, 47kDa, and 16kDa). These mapped to the area of the SynS genome between the gene encoding the putative tail fiber and the gene encoding the putative terminase. No minor capsid or decorative capsid proteins were detected. The copy numbers of the corresponding protein chains were similar to those known for T7, with the exception of the tail fiber, which was present at a number of three chains per particle in comparison to T7's eighteen per particle. / (cont.) Polyclonal antibodies were raised against Syn5 particles. A Western blot with these antibodies showed that the tail fiber and the two unknown fibrous sequences were highly antigenic. This evidence implies that the unknown structures may act as host recognition proteins in addition to the tail fiber. Characterization of these novel proteins may provide insight to the host recognition abilities of cyanophages. An additional study was also carried out, investigating the high temperature limit of the growth of phage P22. The results revealed that the production of infectious particles was limited by the temperature sensitivity of the folding and assembly of the P22 tailspike protein. This work has been published and is included in the Appendix. / by Welkin Hazel Pope. / Ph.D.

Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2005. / Page 296 blank. / Includes bibliographical references. / Marine thecate heterotrophic dinoflagellates likely play an important role in the consumption of primary productivity and in the trophic structure of the plankton, yet we know little about these species. This thesis expanded our understanding of the autecology and evolutionary history of the Protoperidinium and diplopsalids. The distributions of Protoperidinium species off the southwestern coast of Ireland were influenced by physical oceanographic conditions coupled with the availability of preferred prey. The distributions of individual Protoperidinium species varied widely from the distribution of total Protoperidinium, indicating differences in ecologies among species. Certain species of Protoperidinium co-occurred with known preferred phytoplankton prey species. Concentrations of other Protoperidinium species were not related to those of any particular phytoplankton species, indicating that these Protoperidinium may rely on phytoplankton or other food sources beyond those already known, may not be species specific selective feeders, or may have become uncoupled from their preferred prey. The description of the sexual and asexual life history of Protoperidinium steidingerae provided the first account of the life history of any Protoperidinium species. / (cont.) Asexual division occurred by eleutheroschisis within a temporary, immotile cyst, yielding two daughter cells. Daughter cells were initially round and half to two-thirds the size of parent cells, then rapidly increased in size, forming horns before separating. Sexual reproduction was constitutive in clonal cultures, indicating that the species may be homothallic. Fusing gametes were isogamous, and resulted in a planozygote with two longitudinal flagella. Hypnozygotes had a mandatory dormancy period of ca. 70 days. Germination resulted in planomeiocytes with two longitudinal flagella. Nuclear cyclosis may occur in the planomeiocyte stage. A high level of morphological diversity among life history stages of P. steidingerae has led to mis-classification and taxonomic inaccuracy of Protoperidinium species identified from field samples. The large subunit ribosomal DNA (LSU rDNA) molecular phylogeny of the heterotrophic dinoflagellates revealed that the genus Protoperidinium appeared to be recently diverged within the dinoflagellates. In maximum parsimony and neighbor joining analysis, Protoperidinium formed a monophyletic group, evolving from diplopsalid dinoflagellates. / (cont.) In maximum likelihood and Bayesian analyses, however, Protoperidinium was polyphyletic, as the lenticular, diplopsalid heterotroph, Diplopsalis lenticula Bergh, was inserted within the Protoperidinium clade basal to Protoperidinium excentricum (Paulsen) Balech, and Preperidinium meunieri (Pavillard) Elbrichter fell within a separate clade as a sister to the Oceanica section and Protoperidinium steidingerae Balech. In all analyses, the Protoperidinium were divided into two major clades, with members in the Oceanica group and subgenus Testeria in one clade, and the Excentrica, Conica, Pellucida, Pyriforme, and Divergens sections in another clade. The LSU rDNA molecular phylogeny supported the historical morphologically determined sections, but not a simple morphology-based model of evolution based on thecal plate shape. LSU rDNA gene sequences are frequently used to infer the phylogeny of organisms. The many copies of the LSU rDNA found in the genome are thought to be kept homogenous by concerted evolution. In Protoperidinium species, however, there was high intragenomic diversity in the D1-D6 region of the LSU rDNA. For each species, the clone library was usually comprised of one highly represented copy and many unique sequences. / (cont.) Sequence differences were primarily characterized by single base pair substitutions, single base pair insertion/deletions (indels), and/or large indels. Phylogenetic analysis of all clones gave strong support for monophyly of the polymorphic copies of each species, and recovered the same species tree as an analysis using just one sequence per species. Analysis of LSU rDNA gene expression in three species by RT-PCR indicated that copies with fewer substitutions and fewer and smaller indels are expressed, and that 50% or more of the copies are pseudogenes. High intraspecific and intraindividual LSU rDNA sequence variability could lead to inaccurate species phylogenies and over-estimation of species diversity in environmental sequencing studies. This thesis has explored the ecology, life history, molecular phylogeny, and intraspecific DNA sequence variability of marine thecate heterotrohic dinoflagellates using a wide range of methodologies, including field sampling, culturing, microscopy, morphological analyses, histological staining, and molecular biology. The work here has broadened our understanding of the Protoperidinium and diplopsalids, providing new insights into the ecological and evolutionary relationships of these heterotrophs with other plankton species. / by Kristin Elizabeth Gribble. / Ph.D.

Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2008. / Includes bibliographical references. / In this dissertation, I explored metapopulation dynamics and population connectivity, with a focus on the softshell clam, Mya arenaria. I first worked towards developing a method for using elemental signatures retained in the larval shell as a tag of natal habitat. I designed and implemented an experiment to determine whether existing methods commonly used for fishes would be applicable to bivalves. I found that the instrumentation and setup I used were not able to isolate and measure the first larval shell of M. arenaria. In concert with developing this method for bivalves, I reared larval M. arenaria in the laboratory under controlled conditions to understand the environmental and biological factors that may influence elemental signatures in shell. My results show that growth rate and age have significant effects on juvenile shell composition, and that temperature and salinity affect larval and juvenile shell composition in variable ways depending on the element evaluated. I also examined the regional patterns of diversity over the current distribution of M. arenaria using the mitochondrial gene, cytochrome oxidase I (COI). I found minimal variability across all populations sampled, suggesting a recent population expansion in the Northwest Atlantic. Finally, I employed theoretical approaches to understand patch dynamics in a two-patch metapopulation when one patch is of high quality and the other low quality. I developed a matrix metapopulation model and compared growth rate elasticity to patch parameters under variable migration scenarios. I then expanded the model to include stochastic disturbance. I found that in many cases, the spatial distribution of individuals within the metapopulation affects whether growth rate is most elastic to parameters in the good or bad patch. / by Carly A. Strasser. / Ph.D.

Thesis: Ph. D., Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Department of Biology; and the Woods Hole Oceanographic Institution), 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references. / Zooplankton, such as copepods, are highly abundant environmental reservoirs of many bacterial pathogens. Although copepods are known to support diverse and productive bacterial communities, little is understood about whether copepods are affected by bacterial attachment and whether they can regulate these associations through mechanisms such as the innate immune response. This thesis investigates the potential role that copepod physiology may play in regulating Vibrio association and the community structure of its microbiome. To this end, the intrinsic ability of oceanic copepod hosts to transcriptionally respond to mild stressors was first investigated. Specifically, the transcriptional regulation of several heat shock proteins (Hsps), a highly conserved superfamily of molecular chaperones, in the copepod Calanusfinmarchicus was examined and demonstrated that Hsps are a conserved element of the copepod's transcriptional response to stressful conditions and diapause regulation. To then investigate whether copepod hosts respond to and regulate their microbiota, the transcriptomic response of an estuarine copepod Eurytemora affinis to two distinct Vibric species, a free-living strain (V. ordalii 12B09) and a zooplankton specialist (V. sp. F10 9ZB36), was examined with RNA-Seq. Our findings provide evidence that the copepod E. affinis does distinctly recognize and respond to colonizing vibrios via transcriptional regulation of innate immune response elements and transcripts involved in maintaining cuticle integrity. Our work also suggests that association with E. affinis can significantly impact the physiology of Vibrio colonists. Finally, the inter-individual variability of the C.finmarchicus microbiome was examined to identify how specifically and predictably bacterial communities assemble on copepods and whether host physiology influences the bacterial community structure. Our findings suggest that copepods have a predictable "core microbiome" that persists throughout the host's entrance into diapause, a dormancy period characterized by dramatic physiological changes in the host. However, diapausing and active populations harbor distinct flexible microbiomes which may be driven by factors such including the copepod's feeding history, body size, and bacterial interactions. This thesis work highlights the role of copepods as dynamic reservoirs of diverse bacterial communities and implicates copepod host physiology as an important contributor to the activity, abundance, and community structure of its microbiome. / by Amalia Aruda Almada. / Ph. D.

Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2008. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Includes bibliographical references. / The mechanisms of faunal dispersal across ocean basins are key unknowns toward understanding of the modern biogeography and biodiversity of deep-sea fauna. Seamounts are considered to play a defining role in faunal evolution, acting as regional centers of speciation, "stepping-stones" for dispersal, and/or refugia for deep-sea populations. The overarching goal of this dissertation was to examine the role of seamounts in structuring marine biodiversity and biogeography. This study focused on North Atlantic seamounts, specifically the New England seamount chain, the Corner Rise seamounts, and Muir seamount, areas damaged and threatened by deep-sea fisheries and currently a focus of conservation efforts. Videographic analyses of biological community structure revealed distinct faunal assemblages, dominated by the Porifera, Cnidaria, and Echinodermata and structured by geographic region, depth regions (with apparent taxonomic breaks at 1300 m, 2300 m, and 2600 m), and substrate type (including natural/anthropogenic and abiotic substrates and biotic substrates). Amongst these assemblages, seven highly specific coral host- invertebrate associate relationships were identified. To investigate whether or not these broad community patterns were discernible at a genetic level, the 16S mtDNA gene was utilized as a genetic "barcode" within the Class Ophiuroidea, through which 22 putative species were identified, including four target species (Asteroschema clavigera, Ophiocreas oedipus, Ophioplinthaca abyssalis, and Ophioplinthaca chelys) for subsequent population genetic studies. Analyses of mitochondrial 16S and COI gene sequences revealed evidence for recent population expansion and estimates of recent high gene flow across all four species throughout the North Atlantic seamount region. / (cont.) However, genetic differentiation within populations of A. clavigera and 0. chelys within seamount regions was significant, suggesting that historical diversification has been mediated by a long-distance dispersal mechanism that homogenizes this genetic signal on a regional scale. In addition, comparisons of all ophiuroid populations revealed no congruent pattern of historical migration amongst seamounts, which may also be attributed to the varying levels of host specificity and reproductive strategy of each ophiuroid species. These results will guide future studies and conservation efforts to protect seamount communities vulnerable to deep-sea fishery activities. / by Walter W. Cho. / Ph.D.

Thesis: Ph. D., Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Department of Biology; and the Woods Hole Oceanographic Institution), February, 2021 / Cataloged from the official PDF of thesis. / Includes bibliographical references (pages 119-135). / The early life stages of marine fishes play a critical role in population dynamics, largely due to their high abundance, high mortality, and ease of transport in ocean currents. This dissertation demonstrates the value of combining larval data, collected in the field and the laboratory, with model simulations. In Chapter 2, analyses of field observations of ontogenetic vertical distributions of coral reef fish revealed a diversity of behaviors both between and within families. In Caribbean-wide particle-tracking simulations of representative behaviors, surface-dwelling larvae were generally transported longer distances with greater population connectivity amongst habitat patches, while the evenly-distributed vertical behavior and downward ontogenetic vertical migration were similar to one another and led to greater retention near natal sites. However, hydrodynamics and habitat availability created some local patterns that contradicted the overall expectation. / Chapter 3 presents evidence of tuna spawning inside a large no-take marine protected area, the Phoenix Islands Protected Area (PIPA). Despite variation in temperature and chlorophyll, the larval tuna distributions were similar amongst years, with skipjack (Katsuwonus pelamis) and Thunnus spp. tunas observed in all three years. Backtracking simulations indicated that spawning occurred inside PIPA in all 3 study years, demonstrating that PIPA is protecting viable tuna spawning habitat. In Chapter 4, several lines of larval evidence support the classification of the Slope Sea as a major spawning ground for Atlantic bluefin tuna with conditions suitable for larval growth. The abundance of bluefin tuna larvae observed in the Slope Sea aligns with typical observations on the other two spawning grounds. / Age and growth analyses of bluefin tuna larvae collected in the Slope Sea and the Gulf of Mexico in 2016 did not show a growth rate difference between regions, but did suggest that Slope Sea larvae are larger at the onset of exogenous feeding. Collected larvae were backtracked to locations north of Cape Hatteras and forward tracked to show that they would have been retained within the Slope Sea until the onset of swimming. As a whole, this thesis presents valuable contributions to the study of larval fishes and the attendant implications for marine resource management. / by Christina M. Hernández. / Ph. D. / Ph.D. Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Department of Biology; and the Woods Hole Oceanographic Institution)

Thesis (S.M. in Biology)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 1999. / Includes bibliographical references (leaves 23-30). / Phytoplankton mortality (herbivory) and bacterivory were examined experimentally in West Neck Bay and Coecles Harbor, Long Island, NY from April through September, 1998. Small algae (<5 [tm diameter) dominated phytoplankton communities in both ecosystems throughout the summer, and zooplankton were also small (mostly <40 tm). Generally, plankton abundances were indicative of eutrophic ecosystems. Oscillations in standing stocks and mortality of prey indicated tight coupling of growth and grazing mortality in both bays. Phytoplankton mortality rates accounted for the removal of 14% to 65% of total phytoplankton standing stocks daily, while bacterivory accounted for the removal of 14% to 88% of total bacterial standing stocks daily. Estimates of carbon consumption revealed high energy flux through the nano- and microzooplankton assemblages of these estuarine environments. / by Katie Rose Boissonneault Cellineri. / S.M.in Biology

Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 1999. / Includes bibliographical references. / Odontocetes are assumed to use echolocation for navigation and foraging, but neither of these uses of biosonar has been conclusively demonstrated in free-ranging animals. Many bats are known to use echolocation throughout foraging sequences, changing the structure and timing of clicks as they progress towards prey capture. For odontocetes, however, we do not know enough about their foraging behavior to describe such sequences. To conduct detailed behavioral observations of any subject animal, the observer must be able to maintain continuous visual contact with the subject for a period commensurate with the duration of the behavior(s) of interest. Behavioral studies of cetaceans, which spend approximately 95% of their time below the water's surface, have been limited to sampling surface behavior except in special circumstances, e.g. clear-water environments, or with the use of technological tools. I addressed this limitation through development of an observation platform consisting of a remote controlled video camera suspended from a tethered airship with boat-based monitoring, adjustment, and recording of video. The system was used successfully to conduct continuous behavioral observations of bottlenose dolphins in the Sarasota Bay, FL area. This system allowed me to describe previously unreported foraging behaviors and elucidate functions for behaviors already defined but poorly understood. Dolphin foraging was modeled as a stage-structured sequence of behaviors, with the goal-directed feeding event occurring at the end of a series of search, encounter, and pursuit behaviors. The behaviors preceding a feeding event do not occur in a deterministic sequence, but are adaptive and plastic. A single-step transition analysis beginning with prey capture and receding in time has identified significant links between observed behaviors and demonstrated the stage-structured nature of dolphin foraging. Factors affecting the occurrence of specific behaviors and behavioral transitions include mesoscale habitat variation and individual preferences. The role of sound in foraging, especially echolocation, is less well understood than the behavioral component. Recent studies have explored the use of echolocation in captive odontocete foraging and presumed feeding in wild animals, but simultaneous, detailed behavioral and acoustic observations have eluded researchers. The current study used two methods to obtain acoustic data. The overhead video system includes two towed hydrophones used to record 'ambient' sounds of dolphin foraging. The recordings are of the 'ambient' sounds because the source of the sounds, i.e. animal, could not be localized. Many focal follows, however, were conducted with single animals, and from these records the timing of echolocation and other sounds relative to the foraging sequence could be examined. The 'ambient' recordings revealed that single animals are much more vocal than animals in groups, both overall and during foraging. When not foraging, single animals vocalized at a rate similar to the per animal rate in groups of>=2 animals. For single foraging animals, the use of different sound types varies significantly by the habitat in which the animal is foraging. These patterns of use coupled with the characteristics of the different sound types suggest specific functions for each. The presence of multiple animals in a foraging group apparently reduces the need to vocalize, and potential reasons for this pattern are discussed. In addition, the increased vocal activity of single foraging animals lends support to specific hypotheses of sound use in bottlenose dolphins and odontocetes in general. The second acoustic data collection method records sounds known to be from a specific animal. An acoustic recording tag was developed that records all sounds produced by an animal including every echolocation click. The tag also includes an acoustic sampling interval controller and a sensor suite that measures pitch, roll, heading, and surfacing events. While no foraging events occurred while an animal was wearing an acoustic data logger, the rates of echolocation and whistling during different activities, e.g. traveling, were measured. / by Douglas Paul Nowacek. / Ph.D.