Source water inputs and catchment characteristics regulate limnological conditions of shallow subarctic lakes (Old Crow Flats, Yukon, Canada)

2015 ◽  
Vol 72 (7) ◽  
pp. 1058-1072 ◽  
Author(s):  
Ann M. Balasubramaniam ◽  
Roland I. Hall ◽  
Brent B. Wolfe ◽  
Jon N. Sweetman ◽  
Xiaowa Wang
Keyword(s):  
Major Ions ◽  
Nutrient Concentrations ◽  
Source Water ◽  
Subarctic Lakes ◽  
Sparse Vegetation ◽  
Evaporative Concentration ◽  
Tall Shrub ◽  
Strong Control ◽  
Old Crow Flats ◽  
Source Waters

Climate variations exert rapid and strong control on the hydrology of shallow lake-rich subarctic landscapes, but knowledge of the associated effects on limnological conditions remains limited. Based on analysis of water isotope compositions and water chemistry at 56 lakes across Old Crow Flats (Yukon), a large thermokarst landscape, we assess if differences in source water inputs (snowmelt versus rainfall) affect limnological conditions during the ice-free season of 2007 and explore influences of catchment features. Results demonstrate that lakes with snowmelt-dominated source waters, situated in catchments that support tall shrub and woodland vegetation, possess significantly higher (p < 0.05) nutrient (N, P, SiO2) and dissolved organic carbon concentrations than lakes with rainfall-dominated source waters. Conversely, rainfall-dominated lakes, located in catchments dominated by dwarf shrubs and sparse vegetation, have significantly higher concentrations of major ions (Mg2+, Na+, SO42−) and pH. These limnological differences persisted throughout the ice-free season. We suggest that interaction of snowmelt with organic-rich detritus raises nutrient concentrations in snowmelt-dominated lakes and that evaporative-concentration, shoreline erosion and possibly rainfall runoff are processes that raise the ionic content of lakes with rainfall-dominated source waters. Knowledge of these relations improves the ability to anticipate limnological responses to ongoing and future climate and hydrological change in Arctic and subarctic regions.

scholarly journals Tidal and seasonal forcing of dissolved nutrient fluxes in reef communities

2019 ◽  
Vol 16 (9) ◽  
pp. 1921-1935 ◽  
Author(s):  
Renee K. Gruber ◽  
Ryan J. Lowe ◽  
James L. Falter
Keyword(s):  
Mass Transfer ◽  
Nutrient Supply ◽  
Tidal Range ◽  
Nutrient Concentrations ◽  
Nutrient Fluxes ◽  
Flow Measurements ◽  
Uptake Rates ◽  
Reef Communities ◽  
Flow Speeds ◽  
Strong Control

Abstract. Benthic fluxes of dissolved nutrients in reef communities are controlled by oceanographic forcing, including local hydrodynamics and seasonal changes in oceanic nutrient supply. Up to a third of reefs worldwide can be characterized as having circulation that is predominantly tidally forced, yet almost all previous research on reef nutrient fluxes has focused on systems with wave-driven circulation. Fluxes of dissolved nitrogen and phosphorus were measured on a strongly tide-dominated reef platform with a spring tidal range exceeding 8 m. Nutrient fluxes were estimated using a one-dimensional control volume approach, combining flow measurements with modified Eulerian sampling of waters traversing the reef. Measured fluxes were compared to theoretical mass-transfer-limited uptake rates derived from flow speeds. Reef communities released 2.3 mmol m−2 d−1 of nitrate, potentially derived from the remineralization of phytoplankton and dissolved organic nitrogen. Nutrient concentrations and flow speeds varied between the major benthic communities (coral reef and seagrass), resulting in spatial variability in estimated nitrate uptake rates. Rapid changes in flow speed and water depth are key characteristics of tide-dominated reefs, which caused mass-transfer-limited nutrient uptake rates to vary by an order of magnitude on timescales of ∼ minutes–hours. Seasonal nutrient supply was also a strong control on reef mass-transfer-limited uptake rates, and increases in offshore dissolved inorganic nitrogen concentrations during the wet season caused an estimated twofold increase in uptake.

Distinctive control of metabolic pathways byChlorella autotrophicain semicontinuous culture

1996 ◽  
Vol 42 (11) ◽  
pp. 1087-1090 ◽  
Author(s):  
Jaime Fábregas ◽  
Manuel Patiño ◽  
Ever D. Morales ◽  
Adolfo Dominguez ◽  
Ana Otero
Keyword(s):  
Growth Rate ◽  
Metabolic Pathways ◽  
Biochemical Composition ◽  
Nutrient Concentration ◽  
Nutrient Concentrations ◽  
Organic Fraction ◽  
Culture Volume ◽  
Semicontinuous Culture ◽  
Marine Microalga ◽  
Strong Control

The marine microalga Chlorella autotrophica was cultured semicontinuously under light–dark synchronizing conditions at two nutrient concentrations (2 and 4 mmol N∙L−1) and five rates of daily renewal (from 10 to 50% of culture volume). Under such conditions, the biochemical composition of C. autotrophica was strongly influenced by the renewal rate, but unlike other marine microalgae, the nutrient concentration had no effect on the biochemical composition of the organic fraction of the microalga at a given growth rate. Results suggest that this species exerts a strong control over metabolic pathways, independent of the nutrient concentration in the medium.Key words: Chlorella autotrophica, semicontinuous culture, biochemical composition.

Effects of Flooding on Dissolved and Suspended Nutrients in Small Diked Marshes

1986 ◽  
Vol 43 (10) ◽  
pp. 1999-2008 ◽  
Author(s):  
John A. Kadlec
Keyword(s):  
Surface Water ◽  
Indirect Effect ◽  
Interstitial Water ◽  
Major Ions ◽  
Wave Action ◽  
Nutrient Concentrations ◽  
Natural Marsh ◽  
Time And Space ◽  
Emergent Macrophytes ◽  
Delta Marsh

Flooding ten 5- to 7-ha diked marshes in the Delta Marsh, Manitoba, to about 1 m above natural marsh levels did not increase dissolved or suspended nutrient concentrations in the surface water. Dissolved forms of N and P increased in interstitial water, possibly as a direct or indirect effect of death of emergent macrophytes (e.g. cattail, Typha spp.) and associated changes such as wave action and detritus deposition. Concentrations of suspended N, P and C decreased in surface water as a result of flooding, both in absolute terms and relative to concurrent increases shown by natural marsh controls. Concentrations of major ions (Ca2+, Mg2+, Na+, K+[Formula: see text] and Cl−) did not change in response to flooding, but did vary in time and space. A predicted decrease in the concentrations of major ions in interstitial water due to seepage of dilute surface water into the sediment was not detected.

scholarly journals The influence of Arctic Fe and Atlantic fixed N on summertime primary production in Fram Strait, North Greenland Sea

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Stephan Krisch ◽  
Thomas J. Browning ◽  
Martin Graeve ◽  
Kai-Uwe Ludwichowski ◽  
Pablo Lodeiro ◽  
...  
Keyword(s):  
Light Availability ◽  
Arctic Region ◽  
Arctic Sea Ice ◽  
Phytoplankton Growth ◽  
The Arctic ◽  
Nutrient Concentrations ◽  
Phytoplankton Production ◽  
Fram Strait ◽  
Study Region ◽  
Strong Control

Abstract Climate change has led to a ~ 40% reduction in summer Arctic sea-ice cover extent since the 1970s. Resultant increases in light availability may enhance phytoplankton production. Direct evidence for factors currently constraining summertime phytoplankton growth in the Arctic region is however lacking. GEOTRACES cruise GN05 conducted a Fram Strait transect from Svalbard to the NE Greenland Shelf in summer 2016, sampling for bioessential trace metals (Fe, Co, Zn, Mn) and macronutrients (N, Si, P) at ~ 79°N. Five bioassay experiments were conducted to establish phytoplankton responses to additions of Fe, N, Fe + N and volcanic dust. Ambient nutrient concentrations suggested N and Fe were deficient in surface seawater relative to typical phytoplankton requirements. A west-to-east trend in the relative deficiency of N and Fe was apparent, with N becoming more deficient towards Greenland and Fe more deficient towards Svalbard. This aligned with phytoplankton responses in bioassay experiments, which showed greatest chlorophyll-a increases in + N treatment near Greenland and + N + Fe near Svalbard. Collectively these results suggest primary N limitation of phytoplankton growth throughout the study region, with conditions potentially approaching secondary Fe limitation in the eastern Fram Strait. We suggest that the supply of Atlantic-derived N and Arctic-derived Fe exerts a strong control on summertime nutrient stoichiometry and resultant limitation patterns across the Fram Strait region.

scholarly journals Impact of marine vertebrates on Antarctic terrestrial micro-arthropods

2016 ◽  
Vol 28 (3) ◽  
pp. 175-186 ◽  
Author(s):  
Stef Bokhorst ◽  
Peter Convey
Keyword(s):  
Nitrogen Content ◽  
Nitrogen Concentration ◽  
Biotic Interactions ◽  
Terrestrial Ecosystems ◽  
Trophic Levels ◽  
Nutrient Concentrations ◽  
Tissue Quality ◽  
Marine Vertebrates ◽  
The Impact ◽  
Strong Control

AbstractTraits of primary producers associated with tissue quality are commonly assumed to have strong control over higher trophic levels. However, this view is largely based on studies of vascular plants, and cryptogamic vegetation has received far less attention. In this study natural gradients in nutrient concentrations in cryptogams associated with the proximity of penguin colonies on a Maritime Antarctic island were utilized to quantify the impact of nitrogen content on micro-arthropod communities. Proximity to penguin colonies increased the nitrogen concentration of cryptogams, and the penguin source was confirmed by decreasing δ15N values at greater distances from colonies. Micro-arthropod abundance, diversity (H’) and richness declined with distance from the penguin colonies, and was positively correlated with the nitrogen concentrations of cryptogams. Δ15N of micro-arthropods was positively correlated (r2=0.865, P<0.01) with δ15N of the moss Andreaea depressinervis indicating that penguin-derived nitrogen moves through Antarctic food webs across multiple trophic levels. Nitrogen content of cryptogams was correlated with associated micro-arthropods indicating that biotic interactions affect community development in Antarctic terrestrial ecosystems. The spatial patterns of Antarctic biodiversity can therefore be affected by local factors, such as marine vertebrates, beyond existing latitudinal patterns of temperature and water availability.

scholarly journals Biotic responses to multiple aquatic and terrestrial gradients in shallow subarctic lakes (Old Crow Flats, Yukon, Canada)

2017 ◽  
Vol 3 (2) ◽  
pp. 277-300 ◽  
Author(s):  
A.M. Balasubramaniam ◽  
A.S. Medeiros ◽  
K.W. Turner ◽  
R.I. Hall ◽  
B.B. Wolfe
Keyword(s):  
Environmental Change ◽  
Variation Partitioning ◽  
Subarctic Lakes ◽  
Data Set ◽  
Sediment Properties ◽  
One Dimensional ◽  
Catchment Characteristics ◽  
Complex Interactions ◽  
Chironomid Assemblages ◽  
Old Crow Flats

Biotic communities in shallow northern lakes are frequently used to assess environmental change; however, complex interactions among multiple factors remain understudied. Here, we present analyses of a comprehensive data set that evaluates the influence input waters, catchment characteristics, limnology, and sediment properties on diatom and chironomid assemblages in surface sediments of ~49 shallow mainly thermokarst lakes in Old Crow Flats, Yukon. Multivariate analyses and ANOSIM tests identified that composition of diatom (119 taxa) and chironomid (68 taxa) assemblages differs significantly (p < 0.05) between lakes with snowmelt- versus rainfall-dominated input water. Redundancy analyses revealed strong correlation of limnological, sediment, and catchment variables with input waters. Variation partitioning analyses showed that unique effects of limnological variables account for the largest proportion of variation in diatom and chironomid assemblages (17.2% and 12.6%, respectively). Important independent roles of sediment properties (8.5% and 9.5%) and catchment characteristics (4.9% and 5.1%) were also identified. We suggest that the substantial variation shared among these classes (6.1% and 7.9%) is largely attributable to hydrological processes. Our study demonstrates the utility of multi-factor analysis in northern aquatic research and draws attention to the limitations of one-dimensional comparisons and their interpretations when modelling biotic responses to environmental change.

The Divergences of Organic Matter Released from Ozonated Biofilter Inoculated with Indigenous Bacteria

2012 ◽  
Vol 518-523 ◽  
pp. 1813-1816
Author(s):  
Jian Li Lin ◽  
Hsiao Jung Ho ◽  
Jen Jeng Chen ◽  
Chun Yen Chiu ◽  
Shao Wei Liao ◽  
...  
Keyword(s):  
Organic Matter ◽  
Excitation Wavelength ◽  
Source Water ◽  
Fluorescent Intensity ◽  
Indigenous Bacteria ◽  
Operational Process ◽  
Source Waters

In this work, the excitation-emission fluorescent matrix (EEFM) was used to compare the divergence of fluorescent organic properties of the effluents produced from the operation of the bio-stabilizing filter. Four bio-stabilizing filters were simultaneously operated in the combination of both filtered CCL and FS source waters with ozonation (O3/NPDOC=1) and two different indigenous bacteria taken from CCL and FS source water. It found that, two peak locations, 220-230/330nm, 320-330/410-420nm, existed in the effluent of the four bio-stabilizing filters, and one another peak of 280-290/340 nm was appeared in bio-stabilizing filter using FS source water as a substrate. The fluorescent organic matter, with an excitation wavelength of 220-230 nm and 280-290 nm may be attributed as protein-like, while that of 320-330/410-420nm had the possibility of humic-like. The humic-like matter was accumulated in the effluent from the bio-stabilizing filter during the operational process. Bio-stabilizing filter operated with consistent source water and indigenous bacteria could release higher humic-like fluorescent intensity than that with inconsistent source water and indigenous bacteria.

scholarly journals Moving towards Effective First Nations’ Source Water Protection: Barriers, Opportunities, and a Framework

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2957
Author(s):  
Rachael Marshall ◽  
Michele Desjardine ◽  
Jana Levison ◽  
Kim Anderson ◽  
Edward McBean
Keyword(s):  
First Nations ◽  
Indigenous Communities ◽  
Indigenous Research ◽  
Source Water ◽  
Water Protection ◽  
Governmental Organizations ◽  
Non Governmental Organizations ◽  
Challenges And Opportunities ◽  
Source Water Protection ◽  
Source Waters

It is well known that watershed-based source water protection programs are integral to the provision of clean drinking water. However, the involvement of Indigenous communities in these programs is very limited in Canada, which has contributed to the vulnerability of Indigenous source waters to contamination. Through a partnership with an Anishinaabe community, this research aimed to identify challenges and opportunities for communities and practitioners to improve the protection of Indigenous source waters in the province of Ontario. The methodology followed the Indigenous research principles of relationship, respect, relevance, reciprocity, and responsibility. Interviews and a youth focus group were conducted with Indigenous community members and practitioners from industry, academia, non-governmental organizations (NGOs), and government. Analysis was conducted using an iterative process to develop codes and themes in the qualitative data analysis software NVivo. Results indicated that issues with scale, jurisdiction, the concept of source water protection, representation, funding, and capacity impact efforts to protect Indigenous source waters. Hopeful recent developments and upcoming opportunities were identified, and a water protection framework for First Nation communities in Ontario was developed in partnership with an Anishinaabe water protection committee. Recommendations are provided to multiple sectors for moving forward respectfully, and effectively, towards the protection of Indigenous waters.

scholarly journals Assessing the potential of fluorescence spectroscopy to monitor contaminants in source waters and water reuse systems

2019 ◽  
Vol 5 (2) ◽  
pp. 370-382 ◽  
Author(s):  
Joseph Wasswa ◽  
Natalie Mladenov ◽  
William Pearce
Keyword(s):  
Fluorescence Spectroscopy ◽  
Real Time ◽  
System Performance ◽  
Water Reuse ◽  
Source Water ◽  
Water Control ◽  
Water Contaminants ◽  
Reuse System ◽  
Source Waters

It is of ongoing interest to evaluate real-time instruments for monitoring water contaminants for source water control and water reuse system performance applications.

scholarly journals Tidal and seasonal forcing of dissolved nutrient fluxes in reef communities

2018 ◽  
Author(s):  
Renee K. Gruber ◽  
Ryan J. Lowe ◽  
James L. Falter
Keyword(s):  
Mass Transfer ◽  
Control Volume ◽  
Inorganic Nitrogen ◽  
Nutrient Supply ◽  
Nutrient Concentrations ◽  
Nutrient Fluxes ◽  
Uptake Rates ◽  
Reef Communities ◽  
Flow Speeds ◽  
Strong Control

Abstract. Benthic fluxes of dissolved nutrients in reef communities are controlled by oceanographic forcing including hydrodynamic regime and seasonal changes in oceanic nutrient supply. Up to a third of reefs worldwide can be characterised as having circulation that is tidally-driven, yet almost all previous research on reef nutrient fluxes has focused on systems with wave-driven circulation. Fluxes of dissolved nitrogen and phosphorus were measured on a strongly tide-dominated (spring range > 8 m) reef platform located in the Kimberley region of northwest Australia. A one-dimensional control volume approach was used, which combines continuous measurements of flow with modified Eulerian sampling of waters traversing the reef. Measured fluxes were compared to theoretical mass-transfer-limited uptake rates derived from flow speeds. Reef communities released a moderate amount of nitrate, potentially derived from the remineralization of phytoplankton and dissolved organic nitrogen. Nutrient concentrations and flow speeds varied between the major benthic communities (coral reef and seagrass), resulting in spatial variability in estimated nitrate uptake rates. Rapid changes in flow speed and water depth are key characteristics of tide-dominated reefs, which caused mass-transfer-limited nutrient uptake rates to vary by an order of magnitude on time scales of ~minutes–hours. Seasonal nutrient supply was also a strong control on reef mass-transfer-limited uptake rates, and increases in offshore dissolved inorganic nitrogen concentrations during the wet season caused an estimated twofold increase in uptake.

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