Future trends of dissolved inorganic nitrogen concentrations in Northwestern Mediterranean coastal waters under climate change

2021 ◽  
Vol 282 ◽  
pp. 111739
Author(s):  
Regina Temino-Boes ◽  
Rafael García-Bartual ◽  
Inmaculada Romero ◽  
Rabindranarth Romero-Lopez
Keyword(s):  
Climate Change ◽  
Coastal Waters ◽  
Inorganic Nitrogen ◽  
Future Trends ◽  
Dissolved Inorganic Nitrogen ◽  
Nitrogen Concentrations ◽  
Northwestern Mediterranean

Contribution of macroalgal wrack consumers to dissolved inorganic nitrogen concentrations in intertidal pore waters of sandy beaches

2019 ◽  
Vol 219 ◽  
pp. 363-371 ◽  
Author(s):  
Heili E. Lowman ◽  
Kyle A. Emery ◽  
Lila Kubler-Dudgeon ◽  
Jenifer E. Dugan ◽  
John M. Melack
Keyword(s):  
Inorganic Nitrogen ◽  
Sandy Beaches ◽  
Dissolved Inorganic Nitrogen ◽  
Pore Waters ◽  
Nitrogen Concentrations

Forest detritus and cycling of nitrogen in a mountain lake

1991 ◽  
Vol 21 (7) ◽  
pp. 990-998 ◽  
Author(s):  
Robert C. Wissmar
Keyword(s):  
Total Nitrogen ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Inorganic Nitrogen ◽  
Mountain Lake ◽  
Dissolved Inorganic Nitrogen ◽  
Microbial Oxidation ◽  
Nitrogen Fluxes ◽  
Nitrogen Concentrations ◽  
Definition Of

Small lakes of forested watersheds can receive large subsidies of forest matter, but little is known about the material's role in the cycling of nutrients within these ecosystems. This paper examines the influence of detritus and dissolved nitrogen from a forest on the nitrogen cycle of a small subalpine lake in the Cascade Mountains of Washington during the ice-free period (98 days). Relationships between changing detrital microbial biomass, oxygen uptake rates, and water conditions indicate that dissolved inorganic nitrogen concentrations and water temperatures control the decomposition of the nitrogen-depleted detritus. The microbial respiration rates suggest the probable co-occurrence of several microbial oxidation and reduction reactions that could be cycling nitrogen in oxic–anoxic interfaces of detrital deposits, sediments, and riparian areas. Estimates of nitrogen gains and losses (3 and 7%, respectively) by forest detritus are low in comparison with total nitrogen uptake and releases within the lake during the study period (378 and 347 mg•m−2, respectively) and point to the need to examine other methods for measuring detrital nitrogen fluxes. The total nitrogen input to the lake (2600 mg•m−2 for the study period) from the watershed exceeds the lake output (2120 mg•m−2 for the study period). The low output of total nitrogen appears to be due to retention of dissolved inorganic nitrogen and particulate organic nitrogen within the lake. Most dissolved inorganic nitrogen retained is nitrate suggesting possible losses through denitrification. Dissolved organic nitrogen is the major proportion of the total nitrogen fluxes, but related mass balance errors indicate the need for further definition of both the sources and fates of dissolved organic nitrogen for the ecosystem.

scholarly journals Nutrient criteria to achieve New Zealand’s riverine macroinvertebrate targets

2021 ◽  
Author(s):  
Adam D Canning ◽  
Michael Joy ◽  
Russell G Death
Keyword(s):  
New Zealand ◽  
Inorganic Nitrogen ◽  
Intensive Agriculture ◽  
Dissolved Inorganic Nitrogen ◽  
Nutrient Criteria ◽  
Global Trend ◽  
Dissolved Reactive Phosphorus ◽  
Nitrogen Concentrations ◽  
Reactive Phosphorus ◽  
Environmental Goals

Waterways worldwide are experiencing nutrient enrichment from population growth and intensive agriculture, and New Zealand is part of this global trend. Increasing fertilizer in New Zealand and intensive agriculture have driven substantial water quality declines over recent decades. A recent national directive has set environmental managers a range of riverine ecological targets, including three macroinvertebrate indicators, and requires nutrient criteria be set to support their achievement. To support these national aspirations, we use the minimization-of-mismatch analysis to derive potential nutrient criteria. Given that nutrient and macroinvertebrate monitoring often does not occur at the same sites, we compared nutrient criteria derived at sites where macroinvertebrates and nutrients are monitored concurrently with nutrient criteria derived at all macroinvertebrate monitoring sites and using modelled nutrients. To support all three macroinvertebrate targets, we suggest that suitable nutrient criteria would set median dissolved inorganic nitrogen concentrations at ~0.6 mg/L and median dissolved reactive phosphorus concentrations at ~0.02 mg/L. We recognize that deriving site-specific nutrient criteria requires the balancing of multiple values and consideration of multiple targets, and anticipate that criteria derived here will help and support these environmental goals.

Biogeochemical zonation reveals three zones of nitrogen turnover in the Ems estuary

2021 ◽  
Author(s):  
Gesa Schulz ◽  
Tina Sanders ◽  
Kirstin Dähnke
Keyword(s):  
Stable Isotopes ◽  
Water Column ◽  
Coastal Waters ◽  
Inorganic Nitrogen ◽  
Dissolved Inorganic Nitrogen ◽  
Middle Reach ◽  
Ems Estuary ◽  
Nitrogen Turnover ◽  
Spatial Shift ◽  
Nitrate Distribution

<p>Estuaries are nutrient filters for coastal waters and can act as nitrate sink or source depending on predominant microbial processes, environmental conditions and geomorphological characteristics. Such environmental factors can change along the estuary itself. This study aims to identify different zones of nitrogen turnover in the Ems estuary and to determine the main processes.</p><p>Water column properties, dissolved inorganic nitrogen and dual stable isotopes of nitrate were measured along the Ems estuary during two research cruises in August 2014 and June 2020. Based on mixing calculations and stable isotope changes, we found that the estuary in both years is clearly divided into three zones that vary in the predominant nitrate turnover pathways. This was confirmed by principle component analysis.</p><p>The zonation mainly corresponded to changes in the geomorphology of the estuary, but a spatial shift of the zones occurred between 2014 and 2020. In both years, the most upstream zone acted as a clear nitrate sink. A strong fractionation (~30 ‰) of nitrate stable isotopes points towards removal by water column denitrification in this hyperturbid estuarine section.  In the middle reach of the estuary, nitrification gained in importance, turning this section into a net nitrate source during both sampling campaigns. In contrast to the biogeochemical active inner zones, mixing dominates nitrate distribution in the outermost section of the estuary.</p><p>Overall, the Ems estuary acted as a nitrate sink in both years. However, the zonation showed that relative stable zones of nitrification and denitrification existed along the estuary, which can change – and possibly move – when biogeochemical properties vary. </p>

Stable nitrogen isotopes as indicators of anthropogenic activities in small freshwater systems

2001 ◽  
Vol 58 (5) ◽  
pp. 870-878 ◽  
Author(s):  
James L Lake ◽  
Richard A McKinney ◽  
Frank A Osterman ◽  
Richard J Pruell ◽  
John Kiddon ◽  
...  
Keyword(s):  
Largemouth Bass ◽  
Trophic Position ◽  
Anthropogenic Activities ◽  
Inorganic Nitrogen ◽  
Micropterus Salmoides ◽  
Anthropogenic Activity ◽  
Dissolved Inorganic Nitrogen ◽  
Shoreline Development ◽  
Freshwater Systems ◽  
Nitrogen Concentrations

Stable nitrogen isotope ratios (δ15N) were measured in fish, mussel, and sediment samples taken from 17 small freshwater sites to examine food chain length and trophic position across sites affected by differing levels of anthropogenic activity. Both shoreline development and fish species composition varied greatly among sites, and a range of up to 11.2‰ was found for the δ15N values of largemouth bass (Micropterus salmoides). Fish δ15N values were baseline corrected using unionid mussel (Elliptio complanata) δ15N values. Predators, such as largemouth bass and chain pickerel (Esox niger), exhibited normalized δ15N values that were less variable than those of benthic-feeding fishes. Relationships between δ15N and dissolved inorganic nitrogen concentrations indicated that δ15N was a valid descriptor of eutrophication at sites with low dissolved inorganic nitrogen concentrations. The fraction of residential land in buffer zones surrounding sites was correlated with fish δ15N, indicating that urban development, and presumably human wastewater, resulted in elevated δ15N values in these small freshwater systems.

Dissolved inorganic nitrogen concentrations and fluxes in three British Sitka Spruce plantations

1990 ◽  
Vol 128 (1) ◽  
pp. 103-108 ◽  
Author(s):  
P. A. Stevens ◽  
J. K. Adamson ◽  
B. Reynolds ◽  
M. Hornung
Keyword(s):  
Inorganic Nitrogen ◽  
Sitka Spruce ◽  
Dissolved Inorganic Nitrogen ◽  
Nitrogen Concentrations

scholarly journals Nutrient criteria to achieve New Zealand’s riverine macroinvertebrate targets

2021 ◽  
Author(s):  
Adam D Canning ◽  
Michael Joy ◽  
Russell G Death
Keyword(s):  
New Zealand ◽  
Inorganic Nitrogen ◽  
Intensive Agriculture ◽  
Dissolved Inorganic Nitrogen ◽  
Nutrient Criteria ◽  
Global Trend ◽  
Dissolved Reactive Phosphorus ◽  
Nitrogen Concentrations ◽  
Reactive Phosphorus ◽  
Environmental Goals

Waterways worldwide are experiencing nutrient enrichment from population growth and intensive agriculture, and New Zealand is part of this global trend. Increasing fertilizer in New Zealand and intensive agriculture have driven substantial water quality declines over recent decades. A recent national directive has set environmental managers a range of riverine ecological targets, including three macroinvertebrate indicators, and requires nutrient criteria be set to support their achievement. To support these national aspirations, we use the minimization-of-mismatch analysis to derive potential nutrient criteria. Given that nutrient and macroinvertebrate monitoring often does not occur at the same sites, we compared nutrient criteria derived at sites where macroinvertebrates and nutrients are monitored concurrently with nutrient criteria derived at all macroinvertebrate monitoring sites and using modelled nutrients. To support all three macroinvertebrate targets, we suggest that suitable nutrient criteria would set median dissolved inorganic nitrogen concentrations at ~0.6 mg/L and median dissolved reactive phosphorus concentrations at ~0.02 mg/L. We recognize that deriving site-specific nutrient criteria requires the balancing of multiple values and consideration of multiple targets, and anticipate that criteria derived here will help and support these environmental goals.

Dissolved inorganic nitrogen concentrations in an estuarine tidal flat

2013 ◽  
Vol 65 ◽  
pp. 135-140 ◽  
Author(s):  
Hui Woon Tay ◽  
Karin R. Bryan ◽  
Conrad A. Pilditch
Keyword(s):  
Tidal Flat ◽  
Inorganic Nitrogen ◽  
Dissolved Inorganic Nitrogen ◽  
Nitrogen Concentrations
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