Interactive comment on “ Organic matter dynamics and stable isotopes for tracing sources of suspended sediment ” by Y . Schindler Wildhaber
The paper by Schindler Wildhaber et al. uses stable isotopes and other measures of organic components to determine sources of suspended sediment in a small watershed. The questions are of interest, the background laid out and the literature well represented and integrated. The use of the un-mixing model of Phillips and Gregg is not new for characterizing stream suspended sediment, but is a useful way of differentiating sources. The paper goes on to attempt to link the observed changes with the variations in flow regimes which is of interest hydrologically. However, there are a number of problems with the use of statistics in this paper and while I think there may be many significant findings in the data set presented I think the rationale and justification for the use of many of the statistical tests, including the validation of the tests assump-
Export mechanisms for dissolved organic carbon and nitrate during summer storm events in a glaciated forested catchment in New York, USA
Nitrate and dissolved organic carbon (DOC) concentrations during a summer storm for a forested catchment in the Adirondack Mountains displayed a clear separation in trajectories and timing of maximum values. Nitrate concentrations peaked early on the rising limb of the hydrograph, whereas DOC concentrations gradually increased through the rising limb with maximum concentrations following the discharge peak. Solute data from precipitation, throughfall, soilwater, and ground/till water indicated till water and near‐surface soil waters as the controlling end members for stream NO3− and DOC concentrations respectively. Streamflow concentrations of major base cations (Ca2+ and Mg2+), which were assumed to represent water originating from deep flow paths, matched the NO3− trajectory. These data suggest that streamflow NO3− concentrations are derived from till groundwater and that DOC is derived from near‐surface soil waters. We attributed the early expression of NO3− to the displacement of till waters by infiltrating precipitation. In contrast, we hypothesized that the delayed DOC concentrations occurred with surface and near‐surface runoff from near‐stream wetlands/peatlands and isolated saturated areas that became connected only under conditions of maximum water content in the catchment. Copyright © 2004 John Wiley & Sons, Ltd.
Morpho-biometric Relationship, Relative Condition Factor and Meat Yield of Distant Scallop Bractechlamys vexillum (Reeve, 1853) in Asid Gulf, Philippines
Understanding the relationships of morphometric and biometric characters of a species allows the prediction of one trait from the other and generate a measure of relative condition. These relationships were studied for the Distant scallop Bratechlamys vexillum (Reeve, 1853) in Asid Gulf. Representative samples collected during the dry season (May 2018, n = 99) and wet season (September 2018, n = 100) were used to analyse these relationships through models of simple linear and power regression analyses, revealing allometric growth patterns. For both periods, it was revealed that shell width (SW) is a slightly better predictor than the height (SH) for total weight (TW) (R2 = 0.90 and 0.92) and the adductor muscle weight (AW) (R2 = 0.78 and 0.80). The strong functional relationship was also observed between TW and AW (R2 = 0.80 and 0.81). The relative condition factors (Kn) were high in both seasons. High meat yields were also observed in May (12.77 %) and September (14.26 %). The significant difference in meat yields (P < 0.05) can be a result of the seasonal difference manifested by the dynamics of energy partitioning during gametogenesis and spawning. These biological metrics are vital inputs in analysing mariculture prospects for the resource and a contribution to the scarce information on the biology of the species.