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In order to calculate net community production (NCP) rates on Northeast U.S. Shelf Long-Term Ecological Research (NES-LTER) transect cruises, gas tracer data were collected with a continuous at-sea mass spectrometer. The ratio of O2/Ar, measured continuously from underway water, yields 8,000-15,000 rates of NCP per cruise. Discrete water samples (50 to 150 per cruise) were collected for triple oxygen isotope (TOI) analysis to estimate gross primary production (GPP) rates and ratios of NCP/GPP. Along-shelf (upstream-downstream) transects were conducted in addition to the main across-shelf transect. This data package provides two types of data tables for NES-LTER transect cruises beginning in 2018: a high-frequency continuous Equilibration Inlet Mass Spectrometer (EIMS) table, provided by year, and a low-frequency discrete triple oxygen isotope (TOI) table with all years combined. Rates calculated from these measurements are provided as separate packages, per year, in the EDI repository. 

This data package provides net community production (NCP) and gross oxygen production (GOP, a measure of gross primary production) for the winter and summer Northeast U.S. Shelf Long-Term Ecological Research (NES-LTER) Transect cruises in 2022. Two tables are provided: a high-frequency table with NCP rates calculated from measurements of O2/Ar made continuously by an at-sea equilibrator inlet mass spectrometer (EIMS), and a low-frequency table with both NCP and GOP rates calculated for discrete samples measured post-cruise. The GOP rates were calculated from triple O2 isotopic (TOI) ratios. These data are derived from the EIMS and TOI data for the NES-LTER Transect cruises in EDI data package knb-lter-nes.6.3. 

This data package provides net community production (NCP) and gross oxygen production (GOP, a measure of gross primary production) for the winter, spring, and summer Northeast U.S. Shelf Long-Term Ecological Research (NES-LTER) Transect cruises in 2020. Two tables are provided: a high-frequency table with NCP rates calculated from measurements of O2/Ar made continuously by an at-sea equilibrator inlet mass spectrometer (EIMS), and a low-frequency table with both NCP and GOP rates calculated for discrete samples measured post-cruise. The GOP rates were calculated from triple O2 isotopic (TOI) ratios. These data are derived from the EIMS and TOI data for the NES-LTER Transect cruises in EDI data package knb-lter-nes.6.3. 

This data package provides net community production (NCP) and gross oxygen production (GOP, a measure of gross primary production) for the winter and summer Northeast U.S. Shelf Long-Term Ecological Research (NES-LTER) Transect cruises in 2021. Two tables are provided: a high-frequency table with NCP rates calculated from measurements of O2/Ar made continuously by an at-sea equilibrator inlet mass spectrometer (EIMS), and a low-frequency table with both NCP and GOP rates calculated for discrete samples measured post-cruise. The GOP rates were calculated from triple O2 isotopic (TOI) ratios. These data are derived from the EIMS and TOI data for the NES-LTER Transect cruises in EDI data package knb-lter-nes.6.3. 

Abstract The noble gas signature of incoming Pacific Bottom Water (PBW), when compared to North Atlantic Deep Water, indicates the addition of 450 ± 70 GT a⁻¹glacial melt water to form AABW and subsequently PBW. The downstream evolution of this signature between the southern (20°S to equator) and northern (25°–45°N) bottom waters indicates a decrease in sea level pressure around Antarctica over the past two millennia. Vertical profiles of noble gases in the deep Pacific show exponential relationships with depth with scale heights identical to temperature and salinity. Unlike the other noble gases, helium isotopes show evidence of mid‐depth injection of non‐atmospheric helium. Using observed deviations from exponential behavior, we quantify its magnitude and isotope ratio. There is a clear latitude trend in the isotope ratio of this added helium that decreases from a high exceeding 9 R_A(atmospheric³He/⁴He ratio) in the south to around 8 R_Anear the equator. North of 30–40°N, it systematically decreases northward to a low of ∼2 R_Anorth of 50°N. This decline results from a combination of northward decline in seafloor spreading, release of radiogenic helium from increased sediment thickness, and the possible emission of radiogenic helium through cold seeps along the Alaskan and North American margins. Finally, we derive an improved method of computing the excess helium isotope concentrations and that the distributions of bottom water³He_XS/⁴He_XSare consistent with what is known about bottom water flow patterns and the input of low³He/⁴He sedimentary helium.