Hawaii Ocean Experiment - Dynamics of Light and Nutrients (HOE-DYLAN)

Unicellular cyanobacteria group A (UCYN-A) is a widely distributed marine nitrogen-fixing cyanobacterium that provides biologically available nitrogen to the world's oceans and is thus important for ocean productivity. The genomic diversity within UCYN-A is not well known and recent analysis has shown the existence of four phylogenetically distinct UCYN-A clades. The goal of this study is to discover the distribution and abundance of different UCYN-A clades in order to investigate the diversity of UCYN-A in samples collected from Station ALOHA. The polymerase chain reaction targeting UCYN-A genes from ALOHA samples will be done to assess various environmental factors that may be driving UCYN-A diversity at this site; this may ultimately help us better decipher the availability of fixed nitrogen sources in various oceanic regions.

I am a graduate student in the MIT/WHOI Joint Program working with Sony Dyhrman. I am interested in applying eukaryotic metatranscriptomic profiling to better understand how phytoplankton (particularly diatom) blooms form and evolve in the NPSG. Through a series of in situ samplings and microcosm-scale fertilization experiments, I will attempt to tease apart how the community metatranscriptome is modulated by different nutritional drivers that may stimulate phytoplankton blooms.

I am a graduate student in Paul Kemp's lab and I am interested in studying the dynamics of diatom-bacterial interactions in the open ocean, especially at the cell-to-cell level. My work on HOE-DYLAN will be to investigate the changes seen in these interactions that shorter cruises at Station ALOHA may have missed. I am also working with Sonya Dyhrman and Harriet Alexander to see how adding nutrients affects the populations of free and diatom associated bacteria.

The main focus of my activity during HOE-DYLAN will be the interaction between light and the planktonic community. I will try to characterize the temporal variability at Station ALOHA based on its bio-optical properties. Using vertical profilers, I will also estimate some photophysiological characteristics of the algal community and the particle size spectra, and I will try to determine the physical and ecological dynamics responsible for their variability.

I am a marine biochemist and our laboratory will be measuring the distributions of chlorophyll and carotenoid pigments during the HOE-DYLAN cruises. The pigment distributions will be used to identify which phytoplankton groups are present at our study site and to calculate the rates of vertical mixing in the upper ocean.

My objectives for this cruise involve investigating the heterotrophic communities at different depths by comparing remineralization capacities. This work will be a follow-up to several POM and DOP remineralization experiments that will be the focus of my Masters thesis. I look forward to gaining experience and knowledge through collaborative efforts while on this cruise. Collaborators include Sam Wilson, the Church lab, and DeLong lab. I plan to utilize the on board FCM to obtain high-resolution bacterial abundances throughout the incubations, track inorganic N and P production from exogenous P. marinus biomass additions, while determining changes in community structure with metagenomics and CARD-FISH. This work will provide us with a deeper perspective of how nutrient remineralization functions in the upper water column of the open ocean.

I am a postdoc at Ed Boyle's lab at MIT. Our group will be collecting samples to study Fe size-fractionation over the C-MORE 2012 cruises aiming at looking at temporal variability. I will also be taking some samples to study Zn and Cd concentrations and chemical speciation, trying to understand the organic complexation in surface waters and intermediate water masses, compared with some previous studies I've done in the region and at ALOHA as part of my PhD at ODU with John Donat.

During HOE-DYLAN I will be studying the factors controlling the metabolic use of DMSP, specifically the effect of availability of substrate and C1-compounds. I am also interested in looking at the potential competition between Prochlorococcus and heterotrophic bacteria (especially SAR11) for DMSP and methionine. I will also be conducting experiments related to methane production from methylphosphonic acid.

I am an Associate Scientist at the Woods Hole Oceanographic Institution where I work on marine microbial biogeochemistry. My primary interests are in phytoplankton physiological ecology and the microbial cycling of phosphorus. Our group is working to examine the metabolic patterns of eukaryotic phytoplankton and Trichodesmium using metatranscriptome profiling.

I'm exploring the diversity of microbes producing extracellular reactive oxygen species (ROS) with the goal of identifying the microbial groups and enzymatic processes responsible. I will be screening for ROS production before and during the bloom and will isolate organisms found to produce ROS. We will then use metagenomics and transcriptomics to correlate ROS production with the microbial community and active enzymes.

During HOE-DYLAN V, I will be serving as the Junior Chief Scientist. My personal research goals as a part of the Boyle lab will be three-fold. First, we will collect daily surface seawater samples with our trace-metal clean sample collection system, which is called MITESS, in order to monitor the temporal variability of atmospheric dust deposition and subsequent iron (Fe) solubilization in the mixed layer. Second, we will collect a profile on each HOE-DYLAN cruise in order to examine the temporal variability of the distribution and size partitioning of Fe (soluble, colloidal, and particulate), Pb, and other trace metals along the water column, especially near 1200m where we expect hydrothermal input from the nearby Loihi Seamount. Finally, we will also be completing an intercalibration of sample collection methods for colloidal Fe using microfiltration and cross-flow filtration techniques.

I'm joining the cruise as a graduate student from Oregon State University. My research is looking at how ocean acidification affects nitrogen fixing bacteria. On this cruise, I will be focusing on a group of nitrogen fixing bacteria called Trichodesmium. I will collect Trichodesmium colonies and compare their carbon and nitrogen fixation rates under various carbon dioxide, light, and nutrient conditions.

I am a Research Associate II at the Woods Hole Oceanographic Institution working in Sonya Dyhrman's research group. The Dyhrman group is working to characterize the eukaryotic metatranscriptome in the North Pacific Subtropical Gyre. Our group is also studying the distribution and abundance of Trichodesmium and investigating changes in patterns of gene expression that could potentially provide insights into the formation and evolution of Trichodesmium blooms.

I will be working with Ariel Rabines sampling CTD casts for the presence and activity of diazotrophs (via quantifying the nifH gene in both DNA/RNA) and for microbial community characterization using high throughput microarrays. I will also be conducting incubation experiments investigating the response of the microbial community diversity and activity to different N species.

As part of the HOE-DYLAN cruise series, I am conducting daily-scale time-series sampling, observing the depth distributions of cyanobiont-associated diatoms and free-living Crocosphaera phylotypes at Station ALOHA. I am a C-MORE Scholar in the Dept. of Oceanography at the University of Hawaii at Manoa, working with Matthew J. Church and Daniela Böttjer (UH), in collaboration with John B. Waterbury (WHOI).

I'm a research specialist and work for Prof. Ed Boyle in the Dept. of Earth, Atmospheric and Planetary Sciences at MIT. My function on the cruise will be to maintain our sampling systems, which are called VANES. We will be studying the temporal variability of Pb and Fe size partitioning in the surface waters and in the upper 1500m of Station ALOHA.

My research interests include biophysics of photosynthetic electron transport and instrumentation for measurements of photosynthetic activity of phytoplankton and photosynthetic bacteria. Using the multi-spectral Fast Repetition Rate Fluorescence (FRRF) technique I will try to identify the dynamic and vertical patterns of photosynthetic activity specific to different group of photosynthetic organisms with respect to composition of their photosynthetic pigments. The variable fluorescence signal measured at 685 nm and 870 nm will provide information about the presence and activity of anoxygenic aerobic photosynthetic bacteria (AAPBs) in relation to oxygenic photosynthesis. This information should allow determining the effects of light, nutrients, and organic matter on presence and distribution of oxygenic and anoxygenic photosynthesis in the water column, and to quantify the relative contribution of oxygenic and anoxygenic photosynthesis to the energy cycle in the ocean.

My main objective will be to investigate on the factors regulating the utilization of DOM by heterotrophic bacteria at Station ALOHA. With this aim I will perform several nutrient addition experiments throughout the cruise. Microbial respiration at Station ALOHA.

I am a graduate student working on my Ph.D. in biological oceanography at Oregon State University and see this cruise opportunity as a means of learning new techniques and venturing outside of my expertise. My research thus far has focused on harmful algal blooms but on this cruise I will be switching gears to investigate how changes in light affect primary productivity.

Activity and dynamics of photoheterotrophic bacteria at Station ALOHA, in relation to different water masses and episodic events, or isopycnals. Essentially to determine how  photoheterotrophy is characteristic/or not of these different isopycnals, and what the major players are and implications are. In addition I will be sampling for shotgun pyrosequencing of microbial community DNA and RNA to explore evolution of diverse microbial species recovered from these different water masses for the Rappe lab. The goal here is to determine how different isopycnals compare in terms of diversity and abundance of major bacterial groups, gene expression level and sequence conservation.

I am a graduate student in Ed Boyle's trace metal lab at MIT. During HOE-DYLAN V I will be taking and filtering daily surface samples and several water column profiles in order to constrain the temporal variability of dissolved, colloidal, and particulate iron and lead at station ALOHA.

I am joining the HOE-DYLAN cruises as part of the Boyle laboratory at MIT. My research interests focus on the distributions of dissolved trace metals that act as both nutrients to phytoplankton (Co, Fe, Mn, Cd, Zn, Ni, Cu), and as anthropogenic tracers (Pb) On this cruise, I will be a part of our lab's sampling team, collecting seawater with custom-made samplers designed to avoid contamination from the surrounding ship environment. The samples that we collect will be analyzed back in the lab primarily to study the temporal variability of different size fractions of dissolved iron.

My main objective on HOE-DYLAN is to contribute towards the collective Zehr lab sampling goals. This will include collecting samples for analysis of the microbial community via microarray, as well as samples specifically to explore the presence and activity of diazotrophs. In addition, I will be conducting shipboard incubations to study the response of a N₂-fixing organism, Crocosphaera, to phosphate limitation.

My overall research goals are to investigate the temporal and spatial dynamics of photosynthetic picoeukaryote population structure and its environmental controls in the North Pacific Subtropical Gyre. For HOE-DYLAN, I will be looking at daily to weekly scale variability of the diversity of picoeukaryote population with a molecular approach and their activities with a ¹⁴C radiotracer approach. In addition, I will conduct a nitrogen addition experiment to determine the response of photosynthetic picoeukaryote assemblage structure and physiology to variations in nitrogen concentrations and sources.

My research interests are focused on examining the role of reactive oxygen species, particularly superoxide in the water column. During the research cruise the concentration and decay rates of superoxide in the water column will be measured. In addition, the photochemical and biological production of superoxide will be investigated.

I am a Postdoctoral Fellow in Sonya Dyhrman's lab. On this cruise I will collect samples for the study of the abundance and distribution of clades I and II of the nitrogen-fixing cyanobacterium Trichodesmium sp. with depth and time. I also plan to collect surface samples for transcriptome analysis in order to investigate changes in patterns of gene expression that could potentially provide insights into the formation and evolution of Trichodesmium sp. populations.

I am a student in the interdisciplinary geochemistry program at Colorado School of Mines. Hydrogen peroxide, along with other reactive oxygen species (ROS), is involved in trace metal cycling in natural waters. Recent lab experiments have shown that many marine microorganisms produce ROS but little work on has been done to characterize biological production in the field. My goal for this cruise is to characterize biological production and decay rates of hydrogen peroxide under both light and dark conditions.

I am a graduate student working with Dr. Church. As part of the Church lab, I will investigate rates of primary and bacterial production as well as nitrogen fixation during the HOE-DYLAN experiment. My group and I will conduct on-deck incubations to observe how these rates change daily.

Nitrogen fixation by cyanobacteria is an important process that delivers bioavailable nitrogen to the sunlit surface waters at Station ALOHA. In some cases, the nitrogen fixing cyanobacteria exist in symbiosis with eukaryotes. One example of this is the symbiotic association of the cyanobacterium (UCYN-A) with a photosynthetic picoeukaryote. UCYN-A and its associate are not in culture, thus we have a lot to learn about its ecology and function in the open ocean ecosystem. I will be measuring the abundance, diversity, distribution, and gene expression of UCYN-A and its associate at Station ALOHA with the goal of learning which environmental factors are important to the survival and dynamics of this symbiotic association.

My research interests include phytoplankton ecology and photophysiology, marine primary production; environmental forcing and regulation of phytoplankton biomass and production; photosynthesis biophysics with a main interest in studies based on fluorescence bioassays. On the cruise I will be responsible for all Fast Repetition Rate Fluorometry (FRRF) measurements and will try with this technology to characterize phytoplankton assemblages photosynthetic properties. Multispectral FRRF measurements will be taken at the sea surface along the cruise track and on CTD profiles, as well on many of the on-deck incubations. On the August 21- September 11 cruise I will be Junior Chief Scientist and my responsibilities will involve supporting the Chief Scientist and the entire science crew with logistics and research.

I will be collecting samples for the Zehr lab to investigate patterns in the daily abundance and expression of N₂-fixing organisms at Station ALOHA. Such temporal resolution rarely achieved, yet is critical for informing remote instrumentation data interpretation and modeling efforts. I will also be collecting surface and deep-chlorophyll max samples from daily CTD operations to characterize the diversity and function (via mRNA) of the microbial populations present the using a recently developed and optimized high throughput microarray. In addition, we will be performing nutrient-pertubation experiments to examine the response of the phytoplankton assemblages in near-surface waters to different N species.

I am a graduate student in Matt Church's lab at the University of Hawaii at Manoa, where I am interested in microbial biogeochemistry in the North Pacific Subtropical Gyre. During HOE-DYLAN, I plan to examine day-to-day variability in primary production and bacterial production. This will tie in to my work with the Hawaii Ocean Time-series where I measure time and depth variability in rates of dissolved and primary production and how that relates to rates of bacterial production.

My grad research focuses on nitrification at Station ALOHA, which I use molecular approaches to investigate. This summer, I will be collecting my share of nucleic acids as well as helping to make sure that the Church lab rate measurements go smoothly. I look forward to going out to see with all of you.

I am a faculty research assistant at Oregon State University and am looking forward to another cruise in to Station ALOHA! In collaboration with other groups, I will investigate how photoperiod and photoacclimation affect primary productivity measurements and how various measurements of primary productivity compare. I will also assist in experiments characterizing changes in elemental stoichiometry of dissolved and particulate organic matter remineralization by heterotrophic populations.

In collaboration with other C-MORE personnel, I am interested in characterizing the photoacclimation and growth response of photoautotrophs to shifts in light forcing. The overarching question relates to whether or not the phytoplankton carbon to chlorophyll ratio reliably tracks growth rate in natural populations isolated from the surface mixed layer. In addition, we are working to further experiments aimed at characterizing the elemental stoichiometry of particulate and dissolved organic matter remineralization and the temporal response of nitrifiers to organic matter inputs.

My overall research goal is the analysis of reduced gases in the surface seawater. Specific research objectives are to study the hydrogen cycling associated with nitrogen fixation at Stn ALOHA this summer, in particular determining the influence of light intensity. I will also be measuring nitrous oxide and methane concentrations in the water-column, sediment traps, and during various deckboard experiments.