University of Rhode Island

About: University of Rhode Island is a education organization based out in Kingston, Rhode Island, United States. It is known for research contribution in the topics: Population & Bay. The organization has 11464 authors who have published 22770 publications receiving 841066 citations. The organization is also known as: URI & Rhode Island College of Agriculture and the Mechanic Arts.

The Effect of Temperature, Oxygen, Salinity, and Nutrient Enrichment on Estuarine Denitrification Rates Measured with a Modified Nitrogen Gas Flux Technique

Abstract: Nitrogen gas flux was measured from sediments taken from Narragansett Bay, Rhode Island, Boston Harbour, Massachusetts, and the Pawcatuck River Estuary, Rhode Island In addition to studies of field cores taken directly from these systems, intact sediments were taken from Narragansett Bay and maintained in control and nutrient enriched mesocosms Sediment denitrification was measured as a flux of N 2 gas from sediments in N 2 -free chambers The advantages of this technique are that it allows for the direct measurement of denitrification in undisturbed sediment cores under ambient conditions of dissolved nutrients, oxygen, and temperature The challenge of this technique has been to correctly distinguish between N 2 fluxes produced by denitrification activity and fluxes of N 2 caused by sediment porewater de-gassing In this study, anoxic 'control' cores were used to provide continuous checks on the magnitude of porewater de-gassing rates, and allowed measured rates of total N 2 flux to be corrected for this background flux The use of anoxic control cores allowed measurements to begin soon after core collection, without the need for long pre-incubations Observed rates of sediment denitrification ranged from 0 to 195 μmol N 2 m -2 h -1 Highest rates were found in the enriched mesocosms and at a sewage outfall site in Boston Harbour Denitrification rates increased exponentially with temperature and were enhanced by added nutrients Results from the anoxic control cores showed that even after 10 days, the background flux of N 2 from de-gassing porewaters (10-34 μmol N 2 m -2 h -1 ) remained a significant fraction of the overall N 2 flux Although rates of sediment denitrification were stimulated by added nutrients, the overall percentage loss of N from these systems through denitrification did not keep pace with N enrichment, generally accounting for less than 20% of N inputs Thus denitrification may not necessarily provide a significant pathway for alleviating eutrophication effects in coastal waters

Fish vision and the detection of planktonic prey.

Abstract: Planktivorous sunfish of various sizes were studied to ascertain whether growth-related changes in the retina are related to the ability to capture small planktonic crustaceans. Behaviorally, the larger fish detected and captured crustaceans that subtended smaller visual angles. Histological examination of the retinas revealed that the distance between cones, measured in minutes of visual angle, decreased as the animals grew, suggesting that the larger retinas could resolve smaller objects. These correlated behavioral and anatomical results suggest that improved visual resolution contributes to improved predation. This finding provides a selective advantage for the continuous retinal growth noted in many fish.

Sexual media use and relational satisfaction in heterosexual couples

Abstract: This study assessed how sexual media use by one or both members of a romantic dyad relates to relationship and sexual satisfaction. A total of 217 heterosexual couples completed an Internet survey that assessed sexual media use, relationship and sexual satisfaction, and demographic variables. Results revealed that a higher frequency of men’s sexual media use related to negative satisfaction in men, while a higher frequency of women’s sexual media use related to positive satisfaction in male partners. Reasons for sexual media use differed by gender: Men reported primarily using sexual media for masturbation, while women reported primarily using sexual media as part of lovemaking with their partners. Shared sexual media use was associated with higher relational satisfaction compared to solitary sexual media use.

Nonequilibrium clumped isotope signals in microbial methane

Abstract: Methane is a key component in the global carbon cycle, with a wide range of anthropogenic and natural sources. Although isotopic compositions of methane have traditionally aided source identification, the abundance of its multiply substituted "clumped" isotopologues (for example, (13)CH3D) has recently emerged as a proxy for determining methane-formation temperatures. However, the effect of biological processes on methane's clumped isotopologue signature is poorly constrained. We show that methanogenesis proceeding at relatively high rates in cattle, surface environments, and laboratory cultures exerts kinetic control on (13)CH3D abundances and results in anomalously elevated formation-temperature estimates. We demonstrate quantitatively that H2 availability accounts for this effect. Clumped methane thermometry can therefore provide constraints on the generation of methane in diverse settings, including continental serpentinization sites and ancient, deep groundwaters.