Riparian Zone Nitrogen Management through the Development of the Riparian Ecosystem Management Model (REMM) in a Formerly Glaciated Watershed of the US Northeast

The Riparian Ecosystem Management Model (REMM) was developed, calibrated and validated for both hydrologic and water quality data for eight riparian buffers located in a formerly glaciated watershed (upper Pawcatuck River Watershed, Rhode Island) of the US Northeast. The Annualized AGricultural Non-Point Source model (AnnAGNPS) was used to predict the runoff and sediment loading to the riparian buffer. Overall, results showed REMM simulated water table depths (WTDs) and groundwater NO3-N concentrations at the stream edge (Zone 1) in good agreement with measured values. The model evaluation statistics showed that, hydrologically REMM performed better for site 1, site 4, and site 8 among the eight buffers, whereas REMM simulated better groundwater NO3-N concentrations in the case of site 1, site 5, and site 7 when compared to the other five sites. The interquartile range of mean absolute error for WTDs was 3.5 cm for both the calibration and validation periods. In the case of NO3-N concentrations prediction, the interquartile range of the root mean square error was 0.25 mg/L and 0.69 mg/L for the calibration and validation periods, respectively, whereas the interquartile range of d for NO3-N concentrations was 0.20 and 0.48 for the calibration and validation period, respectively. Moreover, REMM estimation of % N-removal from Zone 3 to Zone 1 was 19.7%, and 19.8% of N against actual measured 19.1%, and 26.6% of N at site 7 and site 8, respectively. The sensitivity analyses showed that changes in the volumetric water content between field capacity and saturation (soil porosity) were driving water table and denitrification.

A test of the provisioning hypothesis of recruitment control in Georges Bank haddock

The haddock (Melanogrammus aeglefinus) stock of the Georges Bank region of the US Northeast Continental Shelf displays a pattern of large, episodic recruitments. Among the hypothesized controlling mechanisms is the idea that recruitment events are related to provisioning of pre-spawning haddock by the fall bloom the year before. With the occurrence of a recent large recruitment event in 2013, it would be prudent to retest this hypothesis. Fall bloom magnitude was positively correlated (r=0.645, p=0.005) with haddock survivor ratio (recruits per spawning biomass) including data from the 2013 recruitment. This relationship identifies a pathway of bottom up control of a resource species, thus focusing concern over recent changes in lower trophic level productivity.

Greenhouse gas observations from the Northeast Corridor tower network

We present the organization, structure, instrumentation, and measurements of the Northeast Corridor greenhouse gas observation network. This network of tower-based in-situ carbon dioxide and methane observations was established in 2015 with the goal of quantifying emissions of these gases in urban areas in the north-eastern United States. A specific focus of the network is the cities of Baltimore, Maryland, and Washington, D.C., USA, with a high density of observation stations in these two urban areas. Additional observation stations are scattered throughout the US northeast, established to complement other existing urban and regional networks and to investigate emissions throughout this complex region with a high population density and multiple metropolitan areas. Data described in this paper are archived at the National Institute of Standards and Technology and can be found at https://doi.org/10.18434/M32126 (Karion et al., 2019).