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Abstract: Terrestrial groundwater travels through subterranean estuaries before reaching the sea. Groundwater‐derived nutrients drive coastal water quality, primary production, and eutrophication. We determined how dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), and dissolved organic nitrogen (DON) are transformed within subterranean estuaries and estimated submarine groundwater discharge (SGD) nutrient loads compiling > 10,000 groundwater samples from 216 sites worldwide. Nutrients exhibited complex, nonconservative behavior in subterranean estuaries. Fresh groundwater DIN and DIP are usually produced, and DON is consumed during transport. Median total SGD (saline and fresh) fluxes globally were 5.4, 2.6, and 0.18 Tmol yr−1 for DIN, DON, and DIP, respectively. Despite large natural variability, total SGD fluxes likely exceed global riverine nutrient export. Fresh SGD is a small source of new nutrients, but saline SGD is an important source of mostly recycled nutrients. Nutrients exported via SGD via subterranean estuaries are critical to coastal biogeochemistry and a significant nutrient source to the oceans.

Submarine groundwater discharge (SGD) dynamically links land‐ and ocean‐derived chemical constituents, such as metals, in the coastal ocean. While many metals are sediment‐bound, changing environmental conditions, particularly along the coast, may lead to increased release of metals to their dissolved and more bioavailable form. Here, we review metal behavior, speciation, and drivers of mobilization in the coastal environment under anthropogenic influence. We also model global metal contamination risk to the coastal ocean via SGD considering anthropogenic and hydrogeologic pressures, where tropical regions with high population density, SGD, and acid sulfate soils (4% of the global coast) present the highest risk. Although most SGD studies focus on other analytes, such as nutrients, this review demonstrates the importance of considering SGD as a critical pathway for metals to reach the coastal ocean under rapidly changing environmental conditions. [ABSTRACT FROM AUTHOR]

Subterranean estuaries (STEs) form in the subsurface where fresh groundwater and seawater meet and mix. Subterranean estuaries support a variety of biogeochemical processes including those transforming nitrogen (N). Groundwater is often enriched with dissolved inorganic nitrogen (DIN), and transformations in the STE determine the fate of that DIN, which may be discharged to coastal waters. Nitrification oxidizes ammonium (NH4+) to nitrate, making DIN available for N removal via denitrification. We measured nitrification at an STE, in Virginia, USA using in situ and ex situ methods including conservative mixing models informed by in situ geochemical profiles, an in situ experiment with 15NH4+ tracer injection, and ex situ sediment slurry incubations with 15NH4+ tracer addition. All methods indicated nitrification in the STE, but the ex situ sediment slurries revealed higher rates than both the in situ tracr experiment and mixing model estimations. Nitrification rates ranged 55.0–183.16 μmol N m−2 d−1 based on mixing models, 94.2–225 μmol N m−2 d−1 in the in situ tracer experiment, and 36.6–109 μmol N m−2 d−1 slurry incubations. The in situ tracer experiment revealed higher rates and spatial variation not captured by the other methods. The geochemical complexity of the STE makes it difficult to replicate in situ conditions with incubations and calculations based on chemical profiles integrate over longer timescales, therefore, in situ approaches may best quantify transformation rates. Our data suggest that STE nitrification produces NO3−, altering the DIN pool discharged to overlying water via submarine groundwater discharge. Plain Language Summary: Groundwater mixes with coastal waters in subterranean estuaries that form in the subsurface along coastlines. Groundwater supplies compounds to these systems including nutrients such as nitrogen. Within the subterranean estuary, nitrogen may be transformed, influencing its availability to microbes for removal, its flow through sediments to coastal waters, and its availability to primary producers. Here we measured nitrification, a critical nitrogen cycle process that transforms ammonium to nitrite/nitrate in a subterranean estuary. We used several methods to measure nitrification including mixing models that rely on measured nitrogen concentrations across the groundwater salinity gradient, an isotope labeled nitrogen experiment that allows for tracing of nitrogen in the subsurface over time, and laboratory incubations. All methods indicated active nitrification in the STE, but the laboratory incubations revealed higher rates than both the tracer injections and mixing model estimations. Our data suggest that tracer approaches field conditions and heterogeneity, but that incubations and mixing model estimates are useful for determining control points and net impacts of the subterranean estuary on groundwater, respectively. Nitrification alters the form of nitrogen that is transported to overlying water via submarine groundwater discharge and, therefore, may influence the impact of groundwater derived nitrogen on coastal biogeochemistry. Key Points: Nitrification in the subterranean estuary was observed with both ex situ and in situ measurement methodsEx situ incubation experiments revealed higher nitrification rates than in situ tracer or mixing model calculationsNitrate produced in the subterranean estuary may be exported to overlying coastal waters via submarine groundwater discharge [ABSTRACT FROM AUTHOR]

Background This study examined how gut microbiota diversity and richness relate to T cell aging among 96 healthy adults of all ages. It also explored whether these links differed throughout the lifespan. Methods Peripheral blood was obtained from 96 study participants (N =  96, aged 21–72) to assess mRNA markers of T cell aging (p16 ink4a , p14 ARF , B3gat1, Klrg1) and DNA methylation. T cell aging mRNA markers were combined into an aging index, and the Horvath epigenetic clock algorithm was used to calculate epigenetic age based on DNA methylation status of over 500 loci. Participants also collected a stool sample from which the V4 region of the 16S rRNA gene was sequenced to derive the Shannon and Simpson diversity indices, and the total count of observed operational taxonomic units (richness). Models controlled for BMI, comorbidities, sex, dietary quality, smoking status, physical activity, and sleep quality. Results Lower microbiota richness was associated with higher T cell age based on mRNA markers, but when probing the region of significance, this relationship was only significant among adults 45 years and older (p = .03). Lower Shannon diversity (p = .05) and richness (p = .07) marginally correlated with higher epigenetic age (ie, greater T cell DNA methylation). Conclusions Gut microbiota complexity may correspond with the rate of T cell aging, especially in mid-to-late life. These results suggest an interplay between the gut microbiome and immunological aging that warrants further experimental work. [ABSTRACT FROM AUTHOR]

Romantic relationships are a key health determinant. Partners influence each other's psychological, behavioral, and biological trajectories in ways that can foster health and longevity or fuel disease risk and early mortality. A romantic relationship's health impact is considerable yet has historically garnered limited recognition from government agencies, healthcare providers, and policymakers. World‐wide public health organizations are increasingly attending to the importance of social connection and health and calling for action and intervention to improve social connection. In this review, we identify key areas to act on this call and advance research, practice, and policy on romantic relationships and health: dyadic effects in how partners influence each other's health; the socio‐historical context and systems of social stratification; and couple‐level prevention, intervention, and health‐promotion efforts. We connect these perspectives and offer next steps to further establish romantic relationships as a public health priority and target for policy and programming that foster social connection and health. [ABSTRACT FROM AUTHOR]

Introduction: Spousal caregivers face increased cardiovascular risks; lab studies suggest that autonomic reactivity to patients' physical suffering may play a role. To evaluate this mechanism in daily life, our pilot study characterized the feasibility of recruiting couples for a multimethod, in-home assessment. We examined the usability of the resulting data in an effort to link spousal cardiovascular changes to patient pain expression during couples' everyday interactions. Method: For two 48-hr periods, individuals with rheumatoid arthritis (RA) and their partners wore heart monitors while audio-recordings captured couples' in-home interactions. Interbeat intervals were subsetted in 1-, 2-, and 5-min windows before and after each pain expression. Pre-post difference scores in high-frequency heart rate variability (HF-HRV) and heart rate were examined. Results: Of the 17 screened RA patients, 11 were ineligible, and 3 partners declined. The 3 participating couples completed all study activities. The resulting 288 hr of recordings were coded for patients' RA symptom expression, which varied from none to an average of 11 times daily. One couple had sufficient data for physiological analysis: Contrary to prediction, spouse HF-HRV significantly increased after patient symptom expression. Conclusions: Recruitment rates mirrored other couples studies, and enrolled couples complied with study procedures. In-home conversations were reliably coded and successfully linked to spousal ongoing cardiovascular activity. Preliminary findings highlight the importance of optimal sampling windows and suggest symptom expression as a relevant process for some spouses but not others. We offer recommendations for efficiently scaling up the method in future studies.Keywords: couples, pain expression, parasympathetic activity, in-home assessmentSupplemental materials: http://dx.doi.org/10.1037/fsh0000369.supp, Spousal caregivers face heightened risk for cardiovascular disease and other comorbidities (Vitaliano, Zhang, & Scanlan, 2003). Experimental findings suggest that autonomic reactivity to witnessing patients' physical suffering may exacerbate this [...]

As dyadic health science enters a golden age, important conceptual, theoretical, and technical challenges remain. This forum review brings together perspectives on the burgeoning dyadic literature from several subdisciplines within aging research. We first define key concepts and terms so that interested researchers can navigate the complex and various ways in which dyadic health research is conducted. We discuss exciting scientific advances and close by identifying crucial challenges and considerations that coincide with important future directions for the field. [ABSTRACT FROM AUTHOR]

The current study examined couple-level profiles to reveal systematic patterns of health and well-being in older couples. Using latent profile analysis, dyadic profiles were constructed in a national sample of 535 older, different-sex couples based on couples' marital quality, psychological well-being, and physical health. Results revealed 4 distinct profiles: Maritally Satisfied and Healthy (63.5%), Maritally Dissatisfied and Moderately Healthy (14.7%), Maritally Satisfied with Unhealthy Wives (12.3%), and Maritally Satisfied with Unhealthy Husbands (9.3%). Husband age and education, wife education, and marriage length were significant predictors of class membership. Within-class partner concordance analyses confirmed that the latter two profiles featured the largest discordance between partners' health and well-being. Most couples in this sample of older adults belonged to a class who demonstrated successful aging in all domains. A smaller group maintained high marital quality despite physical and psychological difficulties, and other couples were moderately healthy but maritally dissatisfied. [ABSTRACT FROM AUTHOR]

Marital discord fuels depression, according to decades of research. Most prior studies in this area have focused on macro-longitudinal change in depression over the course of years, and on global ratings of marital satisfaction. Less work has examined fluctuations in depressed mood and marital discord in daily life, and none has investigated associations of short-term patterns with longer-term depressed mood and marital outcomes. Using data from participants in the Midlife in the U.S. project, the current study examined daily associations between marital discord and depressed mood, as well as their links to concurrent and prospective patterns of past-month depressed mood and marital risk. Results showed that, on average, depressed mood rose on days when individuals had an argument or tension with their spouse (i.e., marital discord), after accounting for the roles of other stressors. More frequent daily marital discord was also associated with greater past-month depressed mood and marital risk, above and beyond prior levels. Those with larger depressive mood responses to discord in daily life (i.e., greater reactivity) exhibited higher concurrent past-month depressed mood and greater 10-year increases in depressed mood. As the first study to link daily marital patterns to concurrent and prospective changes in depressed mood and marital outcomes, this investigation uncovered two novel processes—daily marital discord and depressive reactivity—as important for understanding long-term patterns of marital risk and depression. [ABSTRACT FROM AUTHOR]