Nitrogen and Iron Availability Drive Metabolic Remodeling and Natural Selection of Diverse Phytoplankton during Experimental Upwelling

Nearly half of carbon fixation and primary production originates from marine phytoplankton, and much of it occurs in episodic blooms in upwelling regimes. Here, we simulated blooms limited by nitrogen and iron by incubating Monterey Bay surface waters with subnutricline waters and inorganic nutrients and measured the wholecommunity transcriptomic response during mid- and late-bloom conditions. Cell counts revealed that centric and pennate diatoms (largely Pseudo-nitzschia and Chaetoceros spp.) were the major blooming taxa, but dinoflagellates, prasinophytes, and prymnesiophytes also increased. Viral mRNA significantly increased in late bloom and likely played a role in the bloom\u27s demise. We observed conserved shifts in the genetic similarity of phytoplankton populations to cultivated strains, indicating adaptive population-level changes in community composition. Additionally, the density of single nucleotide variants (SNVs) declined in late-bloom samples for most taxa, indicating a loss of intraspecific diversity as a result of competition and a selective sweep of adaptive alleles. We noted differences between mid- and late-bloom metabolism and differential regulation of light-harvesting complexes (LHCs) under nutrient stress. While most LHCs are diminished under nutrient stress, we showed that diverse taxa upregulated specialized, energy-dissipating LHCs in low iron. We also suggest the relative expression of NRT2 compared to the expression of GSII as a marker of cellular nitrogen status and the relative expression of iron starvationinduced protein genes (ISIP1, ISIP2, and ISIP3) compared to the expression of the thiamine biosynthesis gene (thiC) as a marker of iron status in natural diatom communities

Optimising fisheries management in relation to tuna catches in the western central Pacific Ocean: A review of research priorities and opportunities

Some of the most important development goals for the countries and territories of the Western and Central Pacific Ocean (WCPO) involve the sustainable management of their fisheries in light of environmental, economic and social uncertainties. The responses of fish populations to variability in the marine environment have implications for decision making processes associated with resource management. There is still considerable uncertainty in estimating the responses of tuna populations to short-to-medium-term variability and longer-term change in the oceanic environment. A workshop was organised to examine how advances in oceanography, fisheries science and fisheries economics could be applied to the tuna fisheries of the WCPO and in doing so identify research priorities to improve understanding relevant to progressing management. Research priorities identified included: (i) improved parameterisation of end to end ecosystem model components, processes and feedbacks through expanded biological observations and incorporation of higher resolution climate models; (ii) development of seasonal and inter-annual forecasting tools enabling management responses to short-term variability in tuna distributions and abundances; (iii) improved understanding of the population dynamics of and the energy transfer efficiencies between food web components; (iv) assessment of the optimal value of access rights and overall fishery value under multiple scenarios of tuna distribution and abundance and influences on decision making by fisheries managers and fleets and (v) development of management strategy evaluation frameworks for utilisation in the implementing and testing of fishery management procedures and to help prioritise research directions and investment. Issues discussed and research priorities identified during the workshop have synergies with other internationally managed fisheries and therefore are applicable to many other fisheries

Diel transcriptional response of a California Current plankton microbiome to light, low iron, and enduring viral infection

Phytoplankton and associated microbial communities provide organic carbon to oceanic food webs and drive ecosystem dynamics. However, capturing those dynamics is challenging. Here, an in situ, semi-Lagrangian, robotic sampler profiled pelagic microbes at 4 h intervals over ~2.6 days in North Pacific high-nutrient, low-chlorophyll waters. We report on the community structure and transcriptional dynamics of microbes in an operationally large size class (>5 μm) predominantly populated by dinoflagellates, ciliates, haptophytes, pelagophytes, diatoms, cyanobacteria (chiefly Synechococcus), prasinophytes (chiefly Ostreococcus), fungi, archaea, and proteobacteria. Apart from fungi and archaea, all groups exhibited 24-h periodicity in some transcripts, but larger portions of the transcriptome oscillated in phototrophs. Periodic photosynthesis-related transcripts exhibited a temporal cascade across the morning hours, conserved across diverse phototrophic lineages. Pronounced silica:nitrate drawdown, a high flavodoxin to ferredoxin transcript ratio, and elevated expression of other Fe-stress markers indicated Fe-limitation. Fe-stress markers peaked during a photoperiodically adaptive time window that could modulate phytoplankton response to seasonal Fe-limitation. Remarkably, we observed viruses that infect the majority of abundant taxa, often with total transcriptional activity synchronized with putative hosts. Taken together, these data reveal a microbial plankton community that is shaped by recycled production and tightly controlled by Fe-limitation and viral activity

Performance-based Assessment to Transportation Safety Planning for Metropolitan Travel Improvement Study

Nebraska’s Strategic Highway Safety Plan (SHSP) sets an ambitious “Toward Zero Deaths” safety goal that aims to improve highway safety with strategic countermeasures to fatalities and serious injuries on all public roads. This vision is integral to transportation safety management in Nebraska and is advanced by the Metropolitan Travel Improvement Study (MTIS) for Omaha, Nebraska and Council Bluffs, Iowa. This quantitative safety performance study conducted here stands as an important milestone for key decision making for the Nebraska Department of Roads (NDOR) and the Metropolitan Area Planning Agency (MAPA). This study establishes a framework for implementing the quantitative safety evaluation process envisioned in the American Association of State Highway and Transportation Officials Highway Safety Manual (HSM) with the objectives: (1) focusing on the process of identifying freeway and major arterial locations with the greatest safety improvement potential in the MTIS by applying a micro-level network screening method based on the HSM; (2) using the study’s detailed analysis of the most recent 5 years of historical crash data to understand contributing crash factors; and (3) performing predictive safety performance of six strategy packages for design year 2040. With this knowledgebase, safety strategies to mitigate fatal and serious injuries were determined and countermeasures selected in the light of the Federal Highway Administration Crash Modification Factor Clearinghouse. This paper focuses on a performance-based approach to compare safety performance to transportation planning alternatives and provides an analytical framework to assist safety professionals, designers, planners, and policy makers at state and local levels in making informed decisions

Freeway Safety Evaluation: A Quantitative Approach Using Highway Safety Manual to Informed Decisions

Performance-based design in the form of operation and safety in the freeway system plays a significant role in alternative evaluation process. Moreover, performance-based design consistent with Highway Safety Manual is getting more accepted and adopted by the highway agency since it sets specific goals in meeting safety targets that lead to meet performance criteria. Nebraska Department of Roads (NDOR) sets targets by using the systematic safety assessment on design modifications. The application of Highway Safety Manual (HSM) in the safety assessment of freeway alternatives focusing on Metropolitan Travel Improvement Study (MTIS) provides a new direction for making informed decisions at the agency level. With that in mind, this study was conducted with the objectives to perform: (1) safety performance evaluation of alternatives in the MTIS by applying Enhanced Interchange and Freeway Safety Analysis Tool (ISATe); (2) safety performance evaluation of design exceptions; and (3) qualitative safety performance evaluation of sub-options as part of sensitivity analysis for design year 2040. This paper focuses on a performance-based approach to compare safety performance of alternatives and provides information to assist safety professionals, designers, planners, and policy makers at state and local levels in making informed decisions. Finally, this study highlights some of the challenges of using predictive tool recommend by HSM in real applications

Bored pile design in stiff clay I: codes of practice

The assessment of the allowable bearing load of bored piles ‘floating' in stiff clay is a standard engineering task. Although the soil mechanics is universal, engineers designing structures in different parts of the world will need to take into account the pertinent codes of practice. It will be helpful to compare such codes, especially in relation to their treatment of uncertainty in the design of bored piles. This paper presents a series of design calculations for a real set of geotechnical data using four international codes of practice: the Australian, American, European and Russian codes. The National Annexes of Ireland, the Netherlands and the UK are used in conjunction with the European code. This selection of countries covers the three Eurocode 7 design approaches (DA1, DA2 and DA3). A non-codified design method is used to provide a base case for comparative purposes with the six codified calculations. A companion paper investigates the issues of soil mechanics in pile design methods, uncertainty in soil parameters and settlement criteria. </jats:p

Studies on the effect of the apolipoprotein E genotype on the lipid profile in Alzheimer\u27s disease

Objective: To determine whether Apolipoprotein E4 (Apo E4) gene status or ApoE gene dose affect the lipid profile in AD. Background: Links between hypercholesterolemia and AD development continue to grow. Presently, limited information exists about the influence of the Apo E genotype on the lipid profile characteristics in AD. Methods: We examined the lipid profiles (total cholesterol (TC), high-density lipoprotein (HDL), lower-density lipoprotein (LDL), TC/HDL ratio, and triglyceride (TG) levels) of 142 subjects with probable or possible AD (mean age 76.5 ± 8.9 years), not on lipid lowering therapy by Apo E genotype. Assessment was done by gene status and gene dose. Results: ApoE4 gene status did not reveal any significant differences in the lipid profile except for LDL. However, significant differences were observed by ApoE gene dose. Conclusion: ApoE gene status has minimal influence on the lipid panel or mean age in AD. Apo E gene dose does influence the lipid panel with Apo E 2/2, and 2/3 having significantly better lipid panels and older age of onset. ©2006 Bentham Science Publishers Ltd