Nutritional Subsidies Research Articles

Exploring the Role of Fathers in the Women, Infants, and Children (WIC) Supplemental Nutrition Program

Evidence suggests that men can play an influential role in improving pregnancy, breastfeeding, and early childhood outcomes. However, the role that programs like the Women, Infants, and Children (WIC) nutrition program play in fostering paternal participation is not known. While men may not be qualified for WIC, their partners and children may benefit from WIC's nutrition subsidies, health screenings, and nutrition education. Therefore, the primary objective of this research was to explore the experiences, expectations and attitudes of men towards WIC, including their exposure to WIC-Education. This study employed a convergent mixed methods design combining surveys and in-depth interviews. Couples were recruited at WIC offices in Philadelphia, Pennsylvania. Interviews were audio-recoded and transcribed verbatim. Data were analyzed and common themes identified via thematic analysis and verified using NVivo-10 Software. Although this study is ongoing, thus far nine couples have been interviewed (mean age: 32 years; mean number of children: 2). Fathers' experiences were grouped into two primary themes. Emergent themes highlighted the lack of paternal participation, which was exemplified by 78% of men reporting no interaction with WIC (including WIC-Ed). Related sub-themes included coercion fears and WIC office inaccessibility as deterrents to paternal involvement. The second major theme, the need for paternal participation, documented the desires of fathers to improve parenting skills and their knowledge of nutrition in support of their partners and children. There may be missed opportunities for fostering the male role within WIC programming, particularly WIC-Ed.

Assessment of nutritional subsidies to freshwater mussels using a multiple natural abundance isotope approach

Summary Freshwater mussels are a particularly imperilled group of aquatic organisms. To date, there is limited understanding of their dietary and nutritional subsidies, including those from both autochthonous (aquatic) and allochthonous (terrestrial) sources. The aim of this study was to evaluate the relative contributions of potential nutritional resources to mussel biomass using a Bayesian mixing model (MixSIAR) for (i) bulk suspended versus benthic organic matter (OM) pools, (ii) general autochthonous versus allochthonous OM sources and (iii) specific individual OM sources. Nutritional subsidies of five species of freshwater mussels were assessed using natural abundance stable isotopes (δ13C, δ15N, δ2H) and natural radiocarbon (Δ14C). The ranges for each of the four isotopes were similar across all species and sampling dates, and mussel δ13C and δ15N values were similar to those measured in previous studies. Despite relatively low variability in this study, species and temporal differences in mussel δ15N, δ2H and Δ14C values were generally significant (P < 0.05). Based on δ13C values alone, bulk suspended OM subsidised mussel biomass to a greater extent than bulk benthic OM (c. 60 and 40% respectively). Modelling of multiple isotopes indicated that while the collective allochthonous nutritional sources accounted for a significant part (c. 33%) of mussel biomass, autochthonous materials collectively subsidised mussel tissue at about twice this level (c. 67). Significant amounts of 14C‐depleted aged carbon were incorporated into freshwater mussel tissue (mean equivalent 14C age = 1325 ± 68 years BP). Potential nutritional sources were also mostly aged, including benthic algae (1226 ± 556 years BP), zooplankton (1682 years BP), terrestrial soil (10 588 ± 4330 years BP) and suspended particulate OM (1443 ± 57 years BP). No single potential individual nutritional OM source explained the multiple isotopic values of freshwater mussel tissue, indicating that these organisms have a multi‐source and potentially opportunistic diet. Benthic algae and phytoplankton were quantitatively the most important individual OM subsidies to freshwater mussel nutrition at our study site (27 and 19% respectively). Observed seasonal shifts in freshwater mussel isotopic values were minimal, suggesting (i) that mussels may not be seasonally limited by individual nutritional resources and/or (ii) the replacement times of C, N and H in freshwater mussel tissues make detection of temporal nutritional subsidy shifts – if they occur – difficult to discern.

The dominant detritus-feeding invertebrate in Arctic peat soils derives its essential amino acids from gut symbionts.

Supplementation of nutrients by symbionts enables consumers to thrive on resources that might otherwise be insufficient to meet nutritional demands. Such nutritional subsidies by intracellular symbionts have been well studied; however, supplementation of de novo synthesized nutrients to hosts by extracellular gut symbionts is poorly documented, especially for generalists with relatively undifferentiated intestinal tracts. Although gut symbionts facilitate degradation of resources that would otherwise remain inaccessible to the host, such digestive actions alone cannot make up for dietary insufficiencies of macronutrients such as essential amino acids (EAA). Documenting whether gut symbionts also function as partners for symbiotic EAA supplementation is important because the question of how some detritivores are able to subsist on nutritionally insufficient diets has remained unresolved. To answer this poorly understood nutritional aspect of symbiont-host interactions, we studied the enchytraeid worm, a bulk soil feeder that thrives in Arctic peatlands. In a combined field and laboratory study, we employed stable isotope fingerprinting of amino acids to identify the biosynthetic origins of amino acids to bacteria, fungi and plants in enchytraeids. Enchytraeids collected from Arctic peatlands derived more than 80% of their EAA from bacteria. In a controlled feeding study with the enchytraeid Enchytraeus crypticus, EAA derived almost exclusively from gut bacteria when the worms fed on higher fibre diets, whereas most of the enchytraeids' EAA derived from dietary sources when fed on lower fibre diets. Our gene sequencing results of gut microbiota showed that the worms harbour several taxa in their gut lumen absent from their diets and substrates. Almost all gut taxa are candidates for EAA supplementation because almost all belong to clades capable of biosynthesizing EAA. Our study provides the first evidence of extensive symbiotic supplementation of EAA by microbial gut symbionts and demonstrates that symbiotic bacteria in the gut lumen appear to function as partners both for symbiotic EAA supplementation and for digestion of insoluble plant fibres.

The energetic contributions of aquatic primary producers to terrestrial food webs in a mid‐size river system

Rivers are increasingly recognized as providing nutritional subsidies (i.e., energy and nutrients) to adjacent terrestrial food webs via depredation of aquatic organisms (e.g., emergent aquatic insects, crayfish, fish) by terrestrial consumers. However, because these prey organisms assimilate energy from both aquatic (e.g., benthic algae, phytoplankton, aquatic macrophytes) and terrestrial (e.g., riparian leaf detritus) primary producers, river subsidies to terrestrial consumers represent a combination of aquatically and terrestrially derived energy. To date, the explicit contribution of energy derived from aquatic primary producers to terrestrial consumers has not been fully explored yet might be expected to be quantitatively important to terrestrial food webs. At 12 reaches along a 185-km segment of the sixth-order Scioto River system (Ohio, USA), we quantified the relative contribution of energy derived from aquatic primary producers to a suite of terrestrial riparian consumers that integrate the adjacent landscape across multiple spatial scales through their foraging activities (tetragnathid spiders, rove beetles, adult coenagrionid damselflies, riparian swallows, and raccoons). We used naturally abundant stable isotopes (13C and 15N) of periphyton, phytoplankton, macrophytes, and terrestrial vegetation to evaluate the energetic contribution of aquatic primary producers to terrestrial food webs. Shoreline tetragnathid spiders were most reliant on aquatic primary producers (50%), followed by wider-ranging raccoons (48%), damselflies (44%), and riparian swallows (41%). Of the primary producers, phytoplankton (19%) provisioned the greatest nutritional contribution to terrestrial consumers (considered collectively), followed by periphyton (14%) and macrophytes (11%). Our findings provide empirical evidence that aquatic primary producers of large streams and rivers can be a critical nutritional resource for terrestrial food webs. We also show that aquatically derived nutrition contributes to both shoreline and broader-ranging terrestrial consumers and thus may be an important landscape-scale energetic linkage between rivers and upland habitats.

Using stable isotopes and C:N ratios to examine the life‐history strategies and nutritional sources of larval lampreys

Natural abundance stable-isotope analysis (δ(13)C and δ(15)N) and C:N ratios were used to study the ammocoete phase of two common non-parasitic lamprey species (least brook lamprey Lampetra aepyptera and American brook lamprey Lethenteron appendix) in two tributaries of the Ohio River (U.S.A.). The C:N ratios suggest that each species employs different lipid accumulation strategies to support its metamorphosis and recruitment into an adult animal. Ammocoete δ(13)C values generally increased with increasing C:N values. In contrast to δ(13)C, ammocoete δ(15)N values were weakly related to the total length (LT) in L. aepyptera, but positively correlated to both LT and C:N ratios in L. appendix. In L. appendix, C:N also correlated positively with LT, and presumably age. A Bayesian mixing model using δ(13)C and δ(15)N was used to estimate nutritional subsidies of different potential food resources to ammocoetes at each site. The models suggested that although nutritional subsidies to ammocoetes varied as a function of site, ammocoetes were generally reliant on large contributions (42-62% at three sites) from aquatic plants. Contributions from aquatic sediment organic matter were also important at all sites (32-63%) for ammocoetes, with terrestrially derived plant materials contributing smaller amounts (4-33%). These findings provide important insights into the feeding ecology and nutrition of two species of lampreys. They also suggest that similar and other quantitative approaches are required to (1) fully understand how the observed stable-isotopes ratios are established in ammocoetes and (2) better assess ammocoete nutritional subsidies in different natal streams.

Identification of the nutritional resources of larval sea lamprey in two Great Lakes tributaries using stable isotopes

Abstract The sea lamprey ( Petromyzon marinus ) is an important invasive parasitic species in the Laurentian Great Lakes, but the nutritional subsidies supporting the protracted filter feeding ammocoete stage are not well established. We used stable isotope ratios (δ 13 C and δ 15 N) to determine the major sources of autochthonous (aquatically produced) and allochthonous (terrestrially produced) organic matter (OM) to the nutrition of ammocoetes collected in 2010 from the Pigeon and Jordan Rivers in Michigan (USA). Ammocoete δ 13 C was positively correlated with animal length and C:N ratio, but δ 15 N was not correlated with either, suggesting that ammocoetes are primary consumers. We used a Bayesian model (MixSIR) to estimate the contributions of potential nutritional sources to ammocoetes. Estimates suggest that aquatic sediments were most important to ammocoete nutrition (median contributions ranged from 49–51%). Aquatic plants, including macrophytes and algae, were also important to ammocoete nutrition with a median contribution of 29%. Terrestrial plants were generally of lesser but still significant importance to ammocoetes, with a median contribution of 19–39%. Our findings generally agree with those of previous studies that have found that inputs of detrital and recently living OM from aquatic primary producers both provide an important source of nutrition for ammocoetes. The present study provides more quantitative estimates of the different forms of OM supporting ammocoete nutrition and biomass.

Trophic versus structural effects of a marine foundation species, giant kelp (Macrocystis pyrifera).

Foundation species create milieus in which ecosystems evolve, altering species abundances and distribution often to a dramatic degree. Although much descriptive work supports their importance, there remains little definitive information on the mechanisms by which foundation species alter their environment. These mechanisms fall into two basic categories: provision of food or other materials, and modification of the physical environment. Here, we manipulated the abundance of a marine foundation species, the giant kelp Macrocystis pyrifera, in 40×40-m plots at Mohawk Reef off Santa Barbara, California and found that its biomass had a strong positive effect on the abundance of bottom-dwelling sessile invertebrates. We examined the carbon (C) stable isotope values of seven species of sessile invertebrates in the treatment plots to test the hypothesis that this positive effect resulted from a nutritional supplement of small suspended particles of kelp detritus, as many studies have posited. We found no evidence from stable isotope analyses to support the hypothesis that kelp detritus is an important food source for sessile suspension-feeding invertebrates. The isotope composition of invertebrates varied with species and season, but was not affected by kelp biomass, with the exception of two species: the tunicate Styela montereyensis, which exhibited a slight enrichment in C stable isotope composition with increasing kelp biomass, and the hydroid Aglaophenia sp., which showed the opposite effect. These results suggest that modification of the physical habitat, rather than nutritional subsidy by kelp detritus, likely accounts for increased abundance of sessile invertebrates within giant kelp forests.

Distribution and trophic dynamics of riparian tetragnathid spiders in a large river system

Development and agriculture are increasingly encroaching into riparian areas, with largely unknown effects on nearshore arthropods, which are important components of linked aquatic–terrestrial food webs. To assess the environmental determinants of the distribution and trophic dynamics of riparian spiders of the family Tetragnathidae, we characterised riparian habitat, collected emergent aquatic insects, and surveyed spiders in developed and rural landscapes of the Scioto River system, Ohio, USA, which provided a range of riparian land cover, nearshore vegetation types and habitat complexity. We also estimated the trophic position (TP) of Tetragnathidae and the proportion of energetic and nutritional subsidies derived from benthic algae (EBA) using naturally abundant carbon (C) and nitrogen (N) stable isotopes. Model-selection results revealed that tetragnathid spider density (1.57–3.80individualsm–1) was more sensitive to differences in overhanging vegetation than to those in aquatic food resources (i.e. emergent aquatic insects). Tetragnathidae TP, which averaged 3.16 across all 12 study reaches (range: 2.35–3.98), was largely driven by canopy density, shoreline shape, percentage overhanging vegetation and emergent-insect density. Emergent-insect density was the strongest driver of tetragnathid spider EBA (0.04–0.54, µ=0.24). Our study reinforced the notion that riparian spiders ecologically link aquatic and terrestrial ecosystems. In particular, our results further current understanding of the mechanisms affecting riparian spider distribution and trophic dynamics, particularly in the context of larger stream and river systems, given that the propensity of related research has occurred in small streams.

Chloroplast symbiosis in a marine ciliate: ecophysiology and the risks and rewards of hosting foreign organelles

Simultaneous use of both heterotrophic and autotrophic metabolism (“mixotrophy”) is common among protists. Strombidium rassoulzadegani is a planktonic mixotrophic marine ciliate that saves chloroplasts from its algal food and obtains a nutritional subsidy via photosynthesis. Cultures from the northeast, northwest, and southwest Atlantic Ocean show similar numerical response parameters (maximum growth rate, food concentration at which growth is half its maximum, and threshold food concentration for growth), and some isolates have been maintained in vitro for over 3 years. This ciliate grows equally well when fed on the green alga Tetraselmis chui (strain PLY429) or the cryptophyte Rhodomonas lens (strain RHODO). It appears to be an obligate mixotroph, requiring both food and light to achieve positive growth, when feeding on either of these algae. However, it has also been grown for several weeks (>10 generations) heterotrophically on the dinoflagellate Prorocentrum minimum (strain EXUV) during which it grows better in dark than in light. In this paper, we review the ecology of S. rassoulzadegani, discuss some aspects of its photo- and feeding physiology, and speculate on benefits and costs to the ciliate of chloroplast symbiosis.

The embarrassment of riches: agricultural food subsidies, high goose numbers, and loss of Arctic wetlands – a continuing saga

Agriculture has provided a nutritional subsidy to the Anatidae (swans, geese, ducks), which has affected their trophic relationships and the Arctic wetlands where they breed. The Mid-Continent Population of lesser snow geese, which breeds in the Canadian Arctic and which traditionally wintered in the coastal marshes of the Gulf States, now feeds in agricultural landscapes. The geometric growth of this population since 1970 is coincident with increased application of nitrogen to farmland and high crop yields. Widespread availability of agricultural foods allows the birds to meet much of their energy demand for migration and reproduction. Their migration conforms to a stepping stone model linked to land use, but feeding also takes place upon arrival on the Arctic breeding grounds. High bird numbers have dramatically affected coastal marshes of the Canadian Arctic. Foraging has produced alternative stable states characterized by sward destruction and near irreversible changes in soil properties of exposed sediments. Locally, this loss of resilience has adversely affected different groups of organisms, resulting in an apparent trophic cascade. A spring hunt was introduced in 1999 in an attempt to check population growth. The current annual cull is now thought to be higher than the replacement rate. Much of the decline of the Mid-Continent Population is probably linked to shooting, but the harassment of birds that fail to acquire sufficient food for reproduction may contribute. The agricultural food subsidy has led to a mismatch between this avian herbivore and its environment — a consequence of migratory connectivity that links wintering and breeding grounds. Key words: agricultural crops, lesser snow geese, migratory connectivity, Arctic coastal marshes, grubbing, hypersalinity, the spring hunt.

Work Security Impacts in Developing Countries: India

Given the rapid pace of globalization, newly industrialized countries cannot adequately protect workers from emerging hazards. Only 5-10% of workers in developing countries have access to occupational health services. Work-related health problems are exacerbated by a scarcity of resources, socioeconomic dislocation, and poor general health status. The author considers the case of India and looks at its background in occupational safety and health (OSH) regulation, national health policy, and recent experience. He notes the decline in trade unions and rise of hazardous industries, and presents a case study of the situation in the state of Delhi. He concludes that the progress of OSH has stalled since economic reform. The high rate of injury and illness is a bad omen for productivity. Lowering the guard on safety and health will ultimately harm the businesses that currently seek to profit from it. The well-being of workers may deteriorate further if poor enforcement and widespread ignorance of OSH persist. Labor standards must be reevaluated and responsible legislation must be developed. Training and nutrition subsidies should be offered to increase productivity and improve worker health.

Stagnation Without Equity: Patterns of Growth and Inequality in China's Rural Economy

When China's leaders launched rural reforms in the late 1970s, they acknowledged the nation's need to modify its commitment to egalitarianism.1 Slogans such as Tt is glorious to be rich!' and 'Some areas will lead; others will follow!' signalled this fundamental shift in ideology. Leaders backed up these exhortations with a series of concrete policy actions ? establishing the Special Economic Zones and implementing the East Coast-first policy, introducing financial reforms, and initiating the rural industrialization movement. In China's version of the 'trickle down' theory, certain core areas were to take the lead in the modernization process and provide models for other areas to later emulate. Adopting strategies that had been employed

Metabolic implications of modularity: studies on the respiration and growth of Electra pilosa

The mass-specific respiration rate of Electra pilosa is independent of colony size and therefore there is no allometric metabolic constraint on colonial growth rate (modular iteration). Budding, however, is confined to peripheral zooids and so the amount of meristem per unit area of colony declines as the colony grows. Hence the rate of zooid production per individual is a decreasing function of colony size. E. pilosa partly compensates for this, first by increasing the budding rate of peripheral zooids as the colony grows and second by expanding the peripheral meristem into lobes. Among colonial invertebrates, a modular construction frees colonies from metabolic allometry and if modules retain their capacity for replication these may accumulate exponentially until restrained by extrinsic factors. Encrusting forms with strictly two-dimensional growth, however, are constrained by the peripheral location of the budding zone. This may be alleviated by faster budding, perhaps as a result of nutritional subsidies as the colony grows, and by departure from a circular shape.