Variation in sediment and seagrass characteristics reflect multiple stressors along a nitrogen-enrichment gradient in a New England lagoon

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Haviland, K. A., Howarth, R. W., Marino, R., & Hayn, M. Variation in sediment and seagrass characteristics reflect multiple stressors along a nitrogen-enrichment gradient in a New England lagoon. Limnology and Oceanography, 67, (2022): 660-667, https://doi.org/10.1002/lno.12025.We examined concentrations of organic carbon, dissolved sulfides, total sediment sulfur, and stable sulfur isotope ratios in seagrass leaf tissues across a nitrogen-enrichment gradient in a coastal marine ecosystem (Cape Cod, Massachusetts) in 2007–2010 and 2017–2019. We also measured seagrass aboveground and belowground biomass, epibiota biomass, and leaf chlorophyll content. Seagrasses were present at all sites in the former period but were lost at our most nitrogen-impacted site (Snug Harbor) by 2011. In 2007–2010, sediment organic carbon and dissolved sulfides were highest in Snug Harbor and decreased along the gradient; leaf tissues depleted in 34S also indicated higher sulfide intrusion into seagrass tissues in more eutrophic areas. By 2017–2019, sediment organic carbon and pore-water soluble sulfides had decreased in Snug Harbor, but had increased at the intermediate site, to levels found at the most impacted site prior to the seagrass die-off. Again, leaf tissue 34S depletion reflected this pattern, indicating seagrasses were exposed to the highest sulfides at the intermediate site. The decreases in sediment organic carbon and soluble sulfides in Snug Harbor years after the loss of the seagrasses illustrate a feedback between high organic matter in seagrass beds and increasing stressors like elevated soluble sulfides in nutrient-enriched systems. We found significant relationships between sediment conditions and seagrass responses, including greater aboveground to belowground biomass ratios, epibiota biomass, and 34S-depleted leaves at sites with high pore-water sulfide and highly organic sediments. Our research suggests that the reduction of anthropogenic nitrogen entering the harbor is necessary for improving sediment quality and preventing seagrass mortality.The authors thankfully acknowledge as our funding sources: The National Science Foundation Biocomplexity, GRFP, and LTREB programs (grants 0420575, 1654845, and 2018241438), and the Woods Hole SeaGrant program

Apolipoprotein C3 Polymorphisms, Cognitive Function and Diabetes in Caribbean Origin Hispanics

Apolipoprotein C3 (APOC3) modulates triglyceride metabolism through inhibition of lipoprotein lipase, but is itself regulated by insulin, so that APOC3 represents a potential mechanism by which glucose metabolism may affect lipid metabolism. Unfavorable lipoprotein profiles and impaired glucose metabolism are linked to cognitive decline, and all three conditions may decrease lifespan. Associations between apolipoprotein C3 (APOC3) gene polymorphisms and impaired lipid and glucose metabolism are well-established, but potential connections between APOC3 polymorphisms, cognitive decline and diabetes deserve further attention.We examined whether APOC3 single nucleotide polymorphisms (SNPs) m482 (rs2854117) and 3u386 (rs5128) were related to cognitive measures, whether the associations between cognitive differences and genotype were related to metabolic differences, and how diabetes status affected these associations. Study subjects were Hispanics of Caribbean origin (n = 991, aged 45-74) living in the Boston metropolitan area.Cognitive and metabolic measures differed substantially by type II diabetes status. In multivariate regression models, APOC3 m482 AA subjects with diabetes exhibited lower executive function (P = 0.009), Stroop color naming score (P = 0.014) and Stroop color-word score (P = 0.022) compared to AG/GG subjects. APOC3 m482 AA subjects with diabetes exhibited significantly higher glucose (P = 0.032) and total cholesterol (P = 0.028) compared to AG/GG subjects. APOC3 3u386 GC/GG subjects with diabetes exhibited significantly higher triglyceride (P = 0.004), total cholesterol (P = 0.003) and glucose (P = 0.016) compared to CC subjects.In summary, we identified significant associations between APOC3 polymorphisms, impaired cognition and metabolic dysregulation in Caribbean Hispanics with diabetes. Further research investigating these relationships in other populations is warranted

Seagrass (Zostera marina) health in a eutrophic coastal marine ecosystem as affected by multiple environmental stressors: shading, sediment organic matter, total sulfur, and soluble sulfides

Increased organic matter inputs in eutrophic marine coastal systems may lead to high levels of microbial sulfate reduction and elevated concentrations of sulfide in porewaters, resulting in subsequent declines in seagrass health. I examined this process in West Falmouth Harbor, a nitrogen (N)- enriched lagoon in Cape Cod. West Falmouth Harbor can be divided into three sub-basins: Snug Harbor, which is impacted by N-inputs from groundwater and contained seagrass until a die-off event in 2010; the Middle Harbor, which is impacted by N-enrichment and contains seagrass; and the Outer Harbor, which contains a seagrass meadow but is less N-impacted. I found the highest levels of porewater sulfide in the Middle Harbor, with an average rooting zone value of 2.3 mM total soluble sulfide, as well as sediment organic matter values as high as 15%, and average δ34S leaf tissue value of 0.0 ‰, implying plant exposure to isotopically light porewater sulfides. This contrasts with much lower sulfide and sediment organic matter concentrations in the Outer and Snug Harbors, at 1.0 and 0.7 mM for sulfide, and 6% and 8% organic matter, respectively. Soluble sulfide and δ34S values found in 2007 in the innermost, highly eutrophic Snug Harbor sub-basin prior to the seagrass die-off event in 2010 were comparable to 2018 Middle Harbor values, with soluble sulfides at 3.0 mM and leaf tissue δ34S at 0.2 ‰. Additionally, carbon values have decreased in Snug Harbor, from 4.4% in 2010 to 3.6% in 2018. I found indications of poor seagrass health in the Middle Harbor, including belowground biomass averaging 64 g per m2, compared to 106 g per m2 in the Outer Harbor. The Middle Harbor had a normalized difference vegetation index value nearly 2-fold higher than the Outer Harbor, indicating potential light limitation which would decrease seagrass photosynthesis and make them vulnerable to sulfide intrusion. A considerable amount of the light limitation experienced by seagrass in West Falmouth Harbor may result from epiphyte cover, with up to 0.55 mg epiphyte per cm2 seagrass leaf area in both the Middle and Outer Harbors. My study suggests a feedback cycle in West Falmouth Harbor wherein sediment trapping of organic matter in N-enriched, light-limited conditions may highly stress seagrass’s rhizome and root structure, leading to increased susceptibility to other environmental stressors and eventual mortality

Engineering a Bamboo Bicycle

The primary objective of this Major Qualifying Project was to design and construct a bamboo bicycle that could be made available in developing nations and be assembled quickly with minimal training. In order to meet this objective, the project was decomposed into three main components: bicycle joint design, manufacturing fixture design, and safety and testing. The project team was divided into three corresponding groups, utilizing axiomatic design to break down each of the three components. The team successfully manufactured a prototype bamboo bicycle using the Joints Team's system of gussets, the Jig Team's manufacturing fixture, and the bamboo selected by the Safety and Testing Team

Watershed ‘chemical cocktails’: forming novel elemental combinations in Anthropocene fresh waters

Este artículo contiene 25 páginas, 9 figuras.In the Anthropocene, watershed chemical transport is increasingly dominated by novel combinations of elements, which are hydrologically linked together as ‘chemical cocktails.’ Chemical cocktails are novel because human activities greatly enhance elemental concentrations and their probability for biogeochemical interactions and shared transport along hydrologic flowpaths. A new chemical cocktail approach advances our ability to: trace contaminant mixtures in watersheds, develop chemical proxies with high-resolution sensor data, and manage multiple water quality problems. We explore the following questions: (1) Can we classify elemental transport in watersheds as chemical cocktails using a new approach? (2) What is the role of climate and land use in enhancing the formation and transport of chemical cocktails in watersheds? To address these questions, we first analyze trends in concentrations of carbon, nutrients, metals, and salts in fresh waters over 100 years. Next, we explore how climate and land use enhance the probability of formation of chemical cocktails of carbon, nutrients, metals, and salts. Ultimately, we classify transport of chemical cocktails based on solubility, mobility, reactivity, and dominant phases: (1) sieved chemical cocktails (e.g., particulate forms of nutrients, metals and organic matter); (2) filtered chemical cocktails (e.g., dissolved organic matter and associated metal complexes); (3) chromatographic chemical cocktails (e.g., ions eluted from soil exchange sites); and (4) reactive chemical cocktails (e.g., limiting nutrients and redox sensitive elements). Typically, contaminants are regulated and managed one element at a time, even though combinations of elements interact to influence many water quality problems such as toxicity to life, eutrophication, infrastructure corrosion, and water treatment. A chemical cocktail approach significantly expands evaluations of water quality signatures and impacts beyond single elements to mixtures. High-frequency sensor data (pH, specific conductance, turbidity, etc.) can serve as proxies for chemical cocktails and improve real-time analyses of water quality violations, identify regulatory needs, and track water quality recovery following storms and extreme climate events. Ultimately, a watershed chemical cocktail approach is necessary for effectively co-managing groups of contaminants and provides a more holistic approach for studying, monitoring, and managing water quality in the Anthropocene.This work was funded by USDA (award # 2016-67019-25280) and NSF-EPSCoR (#1641157) for supporting collaborations at the AGU Chapman Conference on Extreme Climate Events. Significant funding for data collection/analyses in this paper was provided by NSF EAR1521224, NSF CBET1058502, NSF Coastal SEES1426844, NSF DEB-0423476 and DEB-1027188, NSF RI EPSCoR NEWRnet Grant No. IIA-1330406, EPA ORD, Chesapeake Bay Trust, and Multi-state Regional Hatch Project S-1063.Peer reviewe

Towards age-friendly exergame design : the role of familiarity

Exergames have been shown to be effective in helping older adults maintain their physical abilities. However, it is sometimes difficult for older adults to experiment with exergames due to a perceived digital divide. In this work, we propose to bridge this divide through infusing familiarity design into exergames. Specifically, we identify five sub-constructs of familiarity, namely prior experience, positive emotion, occurrence frequency, level of processing, and retention rate. We evaluate the correlations between these five sub-constructs and familiarity through a field study involving 59 Singaporean older adults. Four exergames designed with different interfaces and tasks were sequentially played by the participants. Questionnaire and interview data about the participants’ assessment of the five sub-constructs and the overall familiarity on different exergames were collected. The analysis results show that all five sub-constructs have significant positive correlations with familiarity. Moreover, there is a high positive correlation between the participants’ perceived familiarity of the exergame and their satisfaction with the exergame. Informed by these results, we propose familiarity design guidelines based on the five sub-constructs for age-friendly exergames.MOH (Min. of Health, S’pore)Accepted versio