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The availability of nitrogen (N) in ocean surface waters affects rates of photosynthesis and marine ecosystem structure. In spite of low dissolved inorganic N concentrations, export production in oligotrophic waters is comparable to more nutrient replete regions. Prior observations raise the possibility that di-nitrogen (N2) fixation supplies a significant fraction of N supporting export production in the Gulf of Mexico. In this study, geochemical tools were used to quantify the relative and absolute importance of both subsurface nitrate and N2 fixation as sources of new N fueling export production in the oligotrophic Gulf of Mexico in May 2017 and May 2018. Comparing the isotopic composition (“δ15N”) of nitrate with the δ15N of sinking particulate N collected during five sediment trap deployments each lasting two to four days indicates that N2 fixation is typically not detected and that the majority (≥80%) of export production is supported by subsurface nitrate. Moreover, no gradients in upper ocean dissolved organic N and suspended particulate N concentration and/or δ15N were found that would indicate significant N2 fixation fluxes accumulated in these pools, consistent with low Trichodesmium spp. abundance. Finally, comparing the δ15N of sinking particulate N captured within vs. below the euphotic zone indicates that during late spring regenerated N is low in δ15N compared to sinking N.

In contrast to its productive coastal margins, the open-ocean Gulf of Mexico (GoM) is notable for highly stratified surface waters with extremely low nutrient and chlorophyll concentrations. Field campaigns in 2017 and 2018 identified low rates of turbulent mixing, which combined with oligotrophic nutrient conditions, give very low estimates for diffusive flux of nitrate into the euphotic zone (< 1 µmol N m−2 d−1). Estimates of local N2-fixation are similarly low. In comparison, measured export rates of sinking particulate organic nitrogen (PON) from the euphotic zone are 2 – 3 orders of magnitude higher (i.e. 462 – 1144 µmol N m−2 d−1). We reconcile these disparate findings with regional scale dynamics inferred independently from remote-sensing products and a regional biogeochemical model and find that laterally-sourced organic matter is sufficient to support >90% of open-ocean nitrogen export in the GoM. Results show that lateral transport needs to be closely considered in studies of biogeochemical balances, particularly for basins enclosed by productive coasts., The middle of the Gulf of Mexico is stratified and highly oligotrophic, yet there are anomalously high fluxes of sinking particulate matter from the euphotic zone. Here the authors show that lateral advection of organic matter supports nitrogen export in the Gulf of Mexico’s open ocean.

Phytoplankton growth and microzooplankton grazing rates were measured in repeated profiles of dilution experiments incubated in situ on a drift array in order to assess microbial production and food web characteristics in the oligotrophic bluefin tuna spawning habitat of the Gulf of Mexico (May peak spawning seasons, 2017–2018). Grazing often exceeded growth with the processes more balanced overall in the surface mixed layer, but biomass accumulated in the mid-euphotic zone. Community production estimates (260–500 mg C m−2 day−1) were low compared to similar open-ocean studies in the Pacific Ocean. Prochlorococcus was a consistent major contributor (113–204 mg C m−2 day−1) to productivity, while diatoms and dinoflagellates (2–10 and 4–13 mg C m−2 day−1, respectively) were consistently low. Prymnesiophytes, the most dynamic component (34–134 mg C m−2 day−1), co-dominated in 2017 experiments. Unexpected imbalances in grazing relative to production were observed for all picoplankton populations (Prochlorococcus, Synechococcus and heterotrophic bacteria), suggesting a trophic cascade in the absence of mesozooplankton predation on large microzooplankton. Study sites with abundant larval tuna had the shallowest deep chlorophyll maxima and significant net positive phytoplankton growth below the mixed layer.

Biomass and composition of the phytoplankton community were investigated in the deep-water Gulf of Mexico (GoM) at the edges of Loop Current anticyclonic eddies during May 2017 and May 2018. Using flow cytometry, high-performance liquid chromatography pigments and microscopy, we found euphotic zone integrated chlorophyll a of ~10 mg m−2 and autotrophic carbon ranging from 463 to 1268 mg m−2, dominated by picoplankton (

During two cruises in the oligotrophic oceanic Gulf of Mexico, we deployed sediment traps at three depths: center of the euphotic zone (EZ) (60 m), base of the EZ (117–151 m), and in the twilight zone (231 m). Organic carbon export declined with depth from 6.4 to 4.6 to 2.4 mmol C m−2 d−1, suggesting that net particle production was concentrated in the upper EZ. Net primary production varied from 24 to 29 mmol C m−2 d−1, slightly more than half in the upper EZ. Export ratios varied from 11 to 25%. Trap measurements of chlorophyll and phaeopigments allowed us to quantify fluxes of fresh phytoplankton and herbivorous fecal pellets, respectively, which were both minor contributors to total flux, although their contributions varied with depth. Phytoplankton flux was more important from the upper to lower EZ; fecal pellets were more important at the EZ base and below. C:N elemental ratios and 13C and 15N isotope analyses indicated particle transformations within and beneath the EZ. 234Th-238U disequilibrium measurements varied, likely reflecting the mixing of water from multiple regions over the ~month-long time-scale of 234Th. Our results highlight the complexity of the biological carbon pump in oligotrophic regions.

Western Atlantic bluefin tuna (ABT) undertake long-distance migrations from rich feeding grounds in the North Atlantic to spawn in oligotrophic waters of the Gulf of Mexico (GoM). Stock recruitment is strongly affected by interannual variability in the physical features associated with ABT larvae, but the nutrient sources and food-web structure of preferred habitat, the edges of anticyclonic loop eddies, are unknown. Here, we describe the goals, physical context, design and major findings of an end-to-end process study conducted during peak ABT spawning in May 2017 and 2018. Mesoscale features in the oceanic GoM were surveyed for larvae, and five multi-day Lagrangian experiments measured hydrography and nutrients; plankton biomass and composition from bacteria to zooplankton and fish larvae; phytoplankton nutrient uptake, productivity and taxon-specific growth rates; micro- and mesozooplankton grazing; particle export; and ABT larval feeding and growth rates. We provide a general introduction to the BLOOFINZ-GoM project (Bluefin tuna Larvae in Oligotrophic Ocean Foodwebs, Investigation of Nitrogen to Zooplankton) and highlight the finding, based on backtracking of experimental waters to their positions weeks earlier, that lateral transport from the continental slope region may be more of a key determinant of available habitat utilized by larvae than eddy edges per se.

Thorium-234 ( 234 Th) is a powerful tracer of particle dynamics and the biological pump in the surface ocean; however, variability in carbon: thorium ratios of sinking particles adds substantial uncertainty to estimates of organic carbon export. We coupled a mechanistic thorium sorption and desorption model to a one-dimensional particle sinking model that uses realistic particle settling velocity spectra. The model generates estimates of 238U 234 Th disequilibrium , particulate organic carbon concentration, and the C: 234Th ratio of sinking particles, which are then compared to in situ measurements from quasi-Lagrangian studies conducted on six cruises in the California Current Ecosystem. Broad patterns observed in in situ measurements, including decreasing C:234Th ratios with depth and a strong correlation between sinking C:234Th and the ratio of vertically-integrated particulate organic carbon (POC) to vertically-integrated total water column 234 Th, were accurately recovered by models assuming either a power law distribution of sinking speeds or a double log normal distribution of sinking speeds. Simulations suggested that the observed decrease in C: 234 Th with depth may be driven by preferential remineralization of carbon by particle-attached microbes . However, an alternate model structure featuring complete consumption and/or disaggregation of particles by mesozooplankton ( e.g. no preferential remineralization of carbon) was also able to simulate decreasing C:234Th with depth (although the decrease was weaker), driven by 234Th adsorption onto slowly sinking particles. Model results also suggest that during bloom decays C:234Th ratios of sinking particles should be higher than expected (based on contemporaneous water column POC), because high settling velocities minimize carbon remineralization during sinking.

The highly stratified, oligotrophic regions of the oceans are predominantly nitrogen limited in the surface ocean and light limited at the deep chlorophyll maximum (DCM). Hence, determining light and nitrogen co-limitation patterns for diverse phytoplankton taxa is crucial to understanding marine primary production throughout the euphotic zone. During two cruises in the deep-water Gulf of Mexico, we measured primary productivity (H13CO3−), nitrate uptake (15NO3−), and ammonium uptake (15NH4+) throughout the water column. Primary productivity declined with depth from the mixed-layer to the DCM, averaging 27.1 mmol C m−2 d−1. The fraction of growth supported by NO3− was consistently low, with upper euphotic zone values ranging from 0.01 to 0.14 and lower euphotic zone values ranging from 0.03 to 0.44. Nitrate uptake showed strong diel patterns (maximum during the day), while ammonium uptake exhibited no diel variability. To parameterize taxon-specific phytoplankton nutrient and light utilization, we used a data assimilation approach (Bayesian Markov Chain Monte Carlo) including primary productivity, nutrient uptake, and taxon-specific growth rate measurements. Parameters derived from this analysis define distinct niches for five phytoplankton taxa (Prochlorococcus, Synechococcus, diatoms, dinoflagellates, and prymnesiophytes) and may be useful for constraining biogeochemical models of oligotrophic open-ocean systems.

We used linear inverse ecosystem modeling techniques to assimilate data from extensive Lagrangian field experiments into a mass-balance constrained food web for the Gulf of Mexico open-ocean ecosystem. This region is highly oligotrophic, yet Atlantic bluefin tuna (ABT) travel long distances from feeding grounds in the North Atlantic to spawn there. Our results show extensive nutrient regeneration fueling primary productivity (mostly by cyanobacteria and other picophytoplankton) in the upper euphotic zone. The food web is dominated by the microbial loop (>70% of net primary productivity is respired by heterotrophic bacteria and protists that feed on them). By contrast, herbivorous food web pathways from phytoplankton to metazoan zooplankton process

We used linear inverse ecosystem modeling techniques to assimilate data from extensive Lagrangian field experiments into a mass-balance constrained food web for the Gulf of Mexico open-ocean ecosystem. This region is highly oligotrophic, yet Atlantic bluefin tuna (ABT) travel long distances from feeding grounds in the North Atlantic to spawn there. Our results show extensive nutrient regeneration fueling primary productivity (mostly by cyanobacteria and other picophytoplankton) in the upper euphotic zone. The food web is dominated by themicrobial loop (>70% of net primary productivity is respired by heterotrophic bacteria and protists that feed on them). By contrast, herbivorous food web pathways from phytoplankton to metazoan zooplankton process, ECOLATUN, ECOlogía trófica comparativa de LArvas de aTUN rojo atlántico (Thunnus thynnus) de las áreas de puesta del Medterraneo-NO y el Golfo de México., SI

Upwelling of nutrient rich waters along continental shelves generates highly productive marine ecosystems affectingplanktonic communities from coastal to offshore domains. Methods to constrain pela...

Author(s): Morrow, RM; Ohman, MD; Goericke, R; Kelly, TB; Stephens, BM; Stukel, MR | Abstract: Predicting marine carbon sequestration in a changing climate requires mechanistic understanding of the processes controlling sinking particle flux under different climatic conditions. The recent occurrence of a warm anomaly (2014–2015) followed by an El Nino (2015–2016) in the southern sector of the California Current System presented an opportunity to analyze changes in the biological carbon pump in response to altered climate forcing. We compare primary production, mesozooplankton grazing, and carbon export from the euphotic zone during quasi-Lagrangian experiments conducted in contrasting conditions: two cruises during warm years - one during the warm anomaly in 2014 and one toward the end of El Nino 2016 – and three cruises during El Nino-neutral years. Results showed no substantial differences in the relationships between vertical carbon export and its presumed drivers (primary production, mesozooplankton grazing) between warm and neutral years. Mesozooplankton fecal pellet enumeration and phaeopigment measurements both showed that fecal pellets were the dominant contributor to export in productive upwelling regions. In more oligotrophic regions, fluxes were dominated by amorphous marine snow with negligible pigment content. We found no evidence for a significant shift in the relationship between mesozooplankton grazing rate and chlorophyll concentration. However, mass-specific grazing rates were lower at low-to-moderate chlorophyll concentrations during warm years relative to neutral years. We also detected a significant difference in the relationship between phytoplankton primary production and photosynthetically active radiation between years: at similar irradiance and nutrient concentrations, productivity decreased during the warm events. Whether these changes resulted from species composition changes remains to be determined. Overall, our results suggest that the processes driving export remain similar during different climate conditions, but that species compositional changes or other structural changes require further attention.

Estimating interannual variability in carbon export is a key goal of many marine biogeochemical studies. However, due to variations in export mechanisms between regions, generalized models used to estimate global patterns in export often fail when used for intra-regional analysis. We present here a region-specific model of export production for the California Current Ecosystem (CCE) parameterized using intensive Lagrangian process studies conducted during El Nino-Southern Oscillation (ENSO) warm and neutral phases by the CCE Long-Term Ecological Research (LTER) program. We find that, contrary to expectations from prominent global algorithms, export efficiency (e-ratio = export / primary productivity) is positively correlated with temperature and negatively correlated with net primary productivity (NPP). We attribute these results to the substantial horizontal advection found within the region, and verify this assumption by using a Lagrangian particle tracking model to estimate water mass age. We further suggest that sinking particles in the CCE are comprised of a recently-produced, rapidly-sinking component (likely mesozooplankton fecal pellets) and a longer-lived, slowly-sinking component that is likely advected long distances prior to export. We determine a new algorithm for estimating particle export in the CCE from NPP (Export = 0.08 · NPP + 72 mg C m-2 d-1). We apply this algorithm to a two-decade long time series of NPP in the CCE to estimate spatial and interannual variability across multiple ENSO phases. Reduced export during the warm anomaly of 2014-2015 and El Nino 2015-2016 resulted primarily from decreased export in the coastal upwelling region of the CCE; the oligotrophic offshore region exhibited comparatively low seasonal and interannual variability in flux. The model resolves intra-regional patterns of in situ export measurements, and provides a valuable contrast to global export models.

We used extensive ecological and biogeochemical measurements obtained from quasi-Lagrangian experiments during two California Current Ecosystem Long-Term Ecosystem Research cruises to analyze carbon fluxes between the epipelagic and mesopelagic zones using a linear inverse ecosystem model (LIEM). Measurement constraints on the model include 14C primary productivity, dilution-based microzooplankton grazing rates, gut pigment-based mesozooplankton grazing rates (on multiple zooplankton size classes), 234Th:238U disequilibrium and sediment trap measured carbon export, and metabolic requirements of micronekton, zooplankton, and bacteria. A likelihood approach (Markov Chain Monte Carlo) was used to estimate the resulting flow uncertainties from a sample of potential flux networks. Results highlight the importance of mesozooplankton active transport (i.e., diel vertical migration) for supplying the carbon demand of mesopelagic organisms and sequestering carbon dioxide from the atmosphere. In nine water parcels ranging from a coastal bloom to offshore oligotrophic conditions, mesozooplankton active transport accounted for 18% - 84% (median: 42%) of the total carbon supply to the mesopelagic, with gravitational settling of POC (12% - 55%; median: 37%) and subduction (2% - 32%; median: 14%) providing the majority of the remainder. Vertically migrating zooplankton contributed to downward carbon flux through respiration and excretion at depth and via consumption loses to predatory zooplankton and mesopelagic fish (e.g. myctophids and gonostomatids). Sensitivity analyses showed that the results of the LIEM were robust to changes in nekton metabolic demands, rates of bacterial production, and mesozooplankton gross growth efficiency. This analysis suggests that prior estimates of zooplankton active transport based on conservative estimates of standard (rather than active) metabolism should be revisited.Contribution to the FieldUnderstanding the flows of carbon within the ocean is important for predicting how global climate will shift; yet even after decades of research, the magnitude with which the ocean sequesters carbon is highly uncertain. One reason behind this uncertainty is that a variety of mechanisms control the balance between carbon input and carbon output within the ocean. The topic of this work is to inspect the role of biological organisms in physically transferring organic carbon from the surface to the deep ocean. As opposed to other mechanisms—such as sinking particles, the biological transfer of carbon is difficult to measure directly and is often quite variable, leading to large uncertainties. Here we use an extensive set of in situ observations off the coast of southern California to model the flow of carbon through the ecosystem. The model determined that in our study area nearly half of the total transfer of carbon from the surface ocean to deep was carried out by zooplankton that swim up to the surface each night to feed. This finding has direct implications for global carbon budgets, which often underestimate this transfer of carbon.

The margin of the western North Pacific Ocean releases redox-active elements like Mn, Co, and Ce into the water column to undergo further transformation through oxide formation, scavenging, and reductive dissolution. Near the margin, the upper ocean waters enriched in these elements are characterized by high dissolved oxygen, low salinity, and low temperature, and are a source of the North Pacific Intermediate Water. High dissolved concentrations are observed across the Western Subarctic Gyre, with a rapid decrease in concentrations away from the margin and across the subarctic-subtropical front. The particulate concentrations of Mn, Co, and Ce are also high in the subarctic surface ocean and enriched relative to Ti and trivalent rare earth elements. Furthermore, the particles enriched in Mn, Co, and Ce coincide at the same depth range, suggesting that these elemental cycles are coupled through microbial oxidation in the subarctic gyre as the waters travel along the margin before being subducted at the subarctic-subtropical front. Away from the margin, the Mn, Co, and Ce cycles decouple, as Mn and Ce settle out as particles while dissolved Co is preserved and transported within the North Pacific Intermediate Water into the central North Pacific Ocean.

Zooplankton are important consumers of sinking particles in the ocean’s twilight zone. However, the impact of different taxa depends on their feeding mode. In contrast to typical suspension-feeding zooplankton, flux-feeding taxa preferentially consume rapidly-sinking particles that would otherwise penetrate into the deep ocean. To quantify the potential impact of two flux-feeding zooplankton taxa (Aulosphaeridae [Rhizaria], and Limacina helicina [euthecosome pteropod]) and the total suspension-feeding zooplankton community, we measured depth-stratified abundances of these organisms during six cruises in the California Current Ecosystem. Using allometric-scaling relationships, we computed the percentage of carbon flux intercepted by flux feeders and suspension feeders. These estimates were compared to direct measurements of carbon flux attenuation made using drifting sediment traps and 238U-234Th disequilibrium. We found that carbon flux attenuation in the shallow twilight zone typically ranged from 500 – 1000 µmol organic C flux remineralized per 10-m vertical depth bin. This equated to approximately 6 – 10% of carbon flux remineralized / 10 m. The two flux-feeding taxa considered in this study could account for a substantial proportion of this flux near the base of the euphotic zone. The mean flux attenuation attributable to Aulosphaeridae was 0.69% / 10 m (median = 0.21%/10 m, interquartile range = 0.04 – 0.81%) at their depth of maximum abundance (~100 m), which would equate to ~ 10% of total flux attenuation in this depth range. The maximum flux attenuation attributable to Aulosphaeridae reached 4.2% / 10 m when these protists were most abundant. L. helicina, meanwhile, could intercept 0.45 – 1.6% of carbon flux / 10 m, which was slightly greater (on average) than the Aulosphaeridae. In contrast, suspension-feeding zooplankton in the mesopelagic (including copepods, euphausiids, appendicularians, and ostracods) had combined clearance rates of 2–81 L m-3 d-1 (mean of 19.6 L m-3 d-1). This implies a substantial impact on slowly sinking particles, but a negligible impact on the presumably rapidly-sinking fecal pellets that comprised the majority of the material collected in sediment traps. Our results highlight the need for a greater research focus on the many taxa that potentially act as flux feeders in the oceanic twilight zone.

Author(s): Stukel, MR; Kelly, TB; Aluwihare, LI; Barbeau, KA; Goericke, R; Krause, JW; Landry, MR; Ohman, MD | Abstract: We investigated variability in the C:234Th ratio of sinking particles and its relationship to changing water column characteristics and plankton ecological dynamics during 29 Lagrangian experiments conducted on six cruises of the California Current Ecosystem Long-Term Ecological Research (CCE-LTER) Program. C:234Th ratios of sinking particles collected by a surface-tethered sediment trap (C:234ThST) varied from 2.3 to 20.5 μmol C dpm−1 over a depth range of 47–150 m. C:234ThST was significantly greater (by a factor of 1.8) than C:234Th ratios of suspended g51-μm particles collected in the same water parcels with in situ pumps. C:234Th ratios of large (g200-μm) sinking particles also exceeded those of smaller sinking particles. C:234ThST decreased with depth from the base of the euphotic zone through the upper twilight zone. C:234ThST was positively correlated with several indices of ecosystem productivity including particulate organic carbon (POC) and chlorophyll (Chl) concentrations, mesozooplankton biomass, and the fraction of Chl g20-μm. Principal component analysis and multiple linear regression suggested that decaying phytoplankton blooms exhibited higher C:234ThST than actively growing blooms at similar biomass levels. C:234ThST was positively correlated with indices of the fractional contribution of fecal pellets in sediment traps when the proportion of fecal pellets was low in the traps, likely because of a correlation between mesozooplankton biomass and other indices of ecosystem productivity. However, when fecal pellets were a more important component of sinking material, C:234ThST decreased with increasing fecal pellet content. C:234ThST was also positively correlated with the Si:C ratio of sinking particles. Across the dataset (and across depths) a strong correlation was found between C:234ThST and the ratio of vertically-integrated POC to vertically-integrated total water column 234Th (vC:234Thtot). A mechanistic one-layer, two-box model of thorium sorption and desorption was invoked to explain this correlation. Two empirical models (one using vC:234Thtot; one using depth and vertically-integrated Chl) were developed to predict C:234Th ratios in this coastal upwelling biome. The former regression (log10(C:234ThST) = 0.43 × log10(vC:234Thtot) + 0.53) was found to also be a reasonable predictor for C:234ThST from diverse regions including the Southern Ocean, Sargasso Sea, Subarctic North Pacific, and Eastern Tropical North Pacific.

We evaluate a recent region-specific model of export production (Kelly et al., 2018) and some similar fits to in situ data for the California Current Ecosystem using satellite data. The model is a simple linear function of net primary productivity (NPP): Export = 0.08 × NPP + 72 where EF is export flux in mg C m−2 d−1. We confirm that contrary to several global algorithms export efficiency (e-ratio = export/primary productivity) is negatively correlated with net primary productivity. We find that linear models with a steeper slope of EF relative to NPP produce better estimates of the variability range. Choice of the EF model parameterization can more than double the estimate of temporal variability (standard deviation) in satellite-derived EF time series. The best estimates of EF were obtained when using average NPP during a preceding period of ~7–8 days. This is in contrast with NPP where the best satellite estimates of in situ NPP were obtained using same day satellite data and the coefficient of determination was monotonically decreasing with increasing time lag. We also find that there is substantial unexplained variability in EF that cannot be explained by existing models.

Oceanographic field programs often use δ15N biogeochemical measurements and in situ rate measurements to investigate nitrogen cycling and planktonic ecosystem structure. However, integrative modeling approaches capable of synthesizing these distinct measurement types are lacking. We develop a novel approach for incorporating δ15N isotopic data into existing Markov Chain Monte Carlo (MCMC) random walk methods for solving linear inverse ecosystem models. We test the ability of this approach to recover food web indices (nitrate uptake, nitrogen fixation, zooplankton trophic level, and secondary production) derived from forward models simulating the planktonic ecosystems of the California Current and Amazon River Plume. We show that the MCMC with δ15N approach typically does a better job of recovering ecosystem structure than the standard MCMC or L2 minimum norm (L2MN) approaches, and also outperforms an L2MN with δ15N approach. Furthermore, we find that the MCMC with δ15N approach is robust to the removal of input equations and hence is well suited to typical pelagic ecosystem studies for which the system is usually vastly under-constrained. Our approach is easily extendable for use with δ13C isotopic measurements or variable carbon:nitrogen stoichiometry.

Paper to Plastics (P2P) is an interdisciplinary program that combines chemistry and biology in a research setting. The goal of this project is 2-fold: to engage students in scientific research and to educate them about sustainability and biodegradable materials. The scientific aim of the project is to recycle unwanted office paper to the useful biodegradable polymer poly(lactic acid) (PLA). Through this program, students learn firsthand how chemistry and biology interact to form useful materials from waste. Students combine biological techniques, such as enzymatic digestion and fermentation, with chemical techniques, such as distillation and catalysis, to accomplish the conversion of waste paper into PLA. Through this summer program, students ultimately become familiar with diverse laboratory techniques, while learning how their scientific interests can be used to address important social problems.

Following the successful launch of the Ozone Mapping and Profiler Suite (OMPS) aboard the Suomi National Polar-orbiting Partnership (SNPP) spacecraft, the NASA OMPS Limb team began an evaluation of instrument and data product performance. The focus of this paper is the instrument performance in relation to the original design criteria. Performance that is closer to expectations increases the likelihood that limb scatter measurements by SNPP OMPS and successor instruments can form the basis for accurate long-term monitoring of ozone vertical profiles. The team finds that the Limb instrument operates mostly as designed and basic performance meets or exceeds the original design criteria. Internally scattered stray light and sensor pointing knowledge are two design challenges with the potential to seriously degrade performance. A thorough prelaunch characterization of stray light supports software corrections that are accurate to within 1% in radiances up to 60 km for the wavelengths used in deriving ozone. Residual stray light errors at 1000nm, which is useful in retrievals of stratospheric aerosols, currently exceed 10%. Height registration errors in the range of 1 km to 2 km have been observed that cannot be fully explained by known error sources. An unexpected thermal sensitivity of the sensor also causes wavelengths and pointing to shift each orbit in the northern hemisphere. Spectral shifts of as much as 0.5nm in the ultraviolet and 5 nm in the visible, and up to 0.3 km shifts in registered height, must be corrected in ground processing.

An ongoing and politically sensitive aspect of proper ecological stewardship revolves around improving the conditions and health of all of the species in the area of concern including both predator and prey species. Human industrial activities have dramatically reduced the land area available to the native species which has placed stresses and fragility into the ecological web. Maintaining proper ecological dynamics has become a critical aspect of policy initiatives designed to safeguard our natural reserves including the establishment of ecological forests and sanctuaries. Herein we outline our proposal to tackle a central issue in wildlife management: improving our knowledge of predator-prey dynamics that vary both temporally and specially in non-linear ways. By leveraging techniques pioneered in other disciplines in addition to the traditional methods, we aim to drastically improve our understanding of the Moose-Grey Wolf interaction and to develop a system with applicability in other regions and other species.

An ongoing and politically sensitive aspect of proper ecological stewardship revolves around improving the conditions and health of all of the species in the area of concern including both predator and prey species. Human industrial activities have dramatically reduced the land area available to the native species which has placed stresses and fragility into the ecological web. Maintaining proper ecological dynamics has become a critical aspect of policy initiatives designed to safeguard our natural reserves including the establishment of ecological forests and sanctuaries. Herein we outline our proposal to tackle a central issue in wildlife management: improving our knowledge of predator-prey dynamics that vary both temporally and specially in non-linear ways. By leveraging techniques pioneered in other disciplines in addition to the traditional methods, we aim to drastically improve our understanding of the Moose-Grey Wolf interaction and to develop a system with applicability in other regions and other species.

Metabolically active pathways tend to be more highly conserved between ecologically similar relatives than other pathways for their critical role in life-functions. The developmental features of Schizosaccharomyces pombe and Saccharomyces cerevisiae may have become quite divergent, but their ecological niche is still quite similar. The functional homology between S. cerevisiae’s MET16p and S. pombe’s was investigated through plasmid insertion and sulfate assimilation assays in S. pombe. Although the S. cerevisiae:MET16p was produced, the S. pombe colonies were unable to utilize extracellular sulfate in the synthesis of Methionine.

Following the successful launch of the Ozone Mapping and Profiler Suite (OMPS) aboard the Suomi National Polar-orbiting Partnership (NPP) spacecraft, the NASA OMPS Limb team began an evaluation of sensor and data product performance in relation to the original goals for this instrument. Does the sensor design work as well as expected, and can limb scatter measurements by NPP OMPS and successor instruments form the basis for accurate long-term monitoring of ozone vertical profiles? While this paper does not address the latter question, the answer to the former is a qualified Yes given this early stage of the mission.