Water transparency and nutrients as controls on phytoplankton along a flood-frequency gradient among lakes of the Mackenzie Delta, western Canadian Arctic

2002 ◽  
Vol 59 (8) ◽  
pp. 1339-1349 ◽  
Author(s):  
Margaret M Squires ◽  
Lance F.W Lesack
Keyword(s):  
Nutrient Limitation ◽  
River Water ◽  
Flood Frequency ◽  
Light Limitation ◽  
Phytoplankton Production ◽  
Mackenzie Delta ◽  
Photosynthetic Rates ◽  
Nutrient Additions ◽  
P Limitation ◽  
Nutrient Conditions

Relatively low phytoplankton production among lakes of the Mackenzie Delta has been attributed to light limitation in frequently flooded lakes and to nutrient limitation among infrequently flooded lakes; productivity peaks have been attributed to optimal light–nutrient conditions at intermediate flood frequency. We found that the distribution and abundance of phytoplankton among a large number of lakes was explained by optimal light–nutrient conditions but not by nutrient or light limitation. For a subset of lakes, seasonal dynamics of biomass were consistent with light limitation and optimal light–nutrient conditions but not nutrient limitation; photosynthetic rates were consistent with optimal light–nutrient conditions and nutrient limitation but not light limitation. Results of dilution–deletion experiments across a light–nutrient gradient indicated transition from light limitation to optimal light–nutrient conditions to nutrient limitation. Surprisingly, adding river water to lake water did not increase photosynthetic rates; this result and experimental incubations in situ during river inflow and lake outflow suggested that continuous supply of river water may be necessary to increase phytoplankton growth rates. Among infrequently flooded lakes, phytoplankton response to nutrient additions showed that phosphorus (P) limitation was no more likely than nitrogen (N) limitation, co-limitation, or no limitation by N or P.

scholarly journals Plants increase silicon content as a response to nitrogen or phosphorus limitation: a case study with Holcus lanatus

2020 ◽  
Author(s):  
Vanessa Minden ◽  
Jörg Schaller ◽  
Harry Olde Venterink
Keyword(s):  
Nutrient Limitation ◽  
Plant Performance ◽  
Light Limitation ◽  
Grass Species ◽  
Holcus Lanatus ◽  
P Deficiency ◽  
Plant Organs ◽  
N Limitation ◽  
P Limitation ◽  
Si Content

Abstract Aims Silicon (Si) has been shown to beneficially affect plant performance under stressful environmental conditions, such as water or nutrient deficiency. Here we tested the effects of two important plant nutrients, nitrogen (N) and phosphorus (P), on Si content in different plant organs in the grass species Holcus lanatus. Methods We studied trait responses to N limitation, balanced nutrient availability and P limitation. Single plant individuals were grown in sand-filled pots in a greenhouse for 2 months. Nitrogen, phosphorus, carbon and silicon contents were determined in leaves, stems and roots, as were leaf and roots traits, biomass production and root enzyme activity. Results Si content was lowest under balanced nutrient supply in all plant organs. Under P limitation Si content was highest in leaves and stems, in roots it was highest under N limitation. Si:C ratios were lowest under balanced conditions, and highest under nutrient limitation. Root phosphatase activity was highest under P limitation and chlorophyll content was lowest under N limitation. Conclusions Our model species assimilated less ‘high cost C’ and took up more ‘low cost Si’ under nutrient limitation, especially under P deficiency. Si potentially plays an important role in different environments, such as nutrient or light limitation, which in turn may be related to different plant strategies, for example higher stem rigidity in high Si plants versus higher stem flexibility in low Si plants. More research is needed to further elucidate the role of silicon in different concepts of trait-environment relationships.

Epilithic algal abundance in relation to anthropogenic changes in phosphorus bioavailability and limitation in mountain rivers

2005 ◽  
Vol 62 (1) ◽  
pp. 174-184 ◽  
Author(s):  
Michelle F Bowman ◽  
Patricia A Chambers ◽  
David W Schindler
Keyword(s):  
Nutrient Limitation ◽  
Inorganic Nitrogen ◽  
Algal Growth ◽  
Point Sources ◽  
Strongly Correlated ◽  
Mountain Rivers ◽  
Nutrient Additions ◽  
P Limitation ◽  
Naturally Occurring ◽  
Algal Abundance

Low-level cultural eutrophication (0.1–3.8 µ·L–1 increase in total phosphorus (TP)) of oligotrophic mountain rivers resulted in 4- to 30-fold increases in benthic algal abundance. Because anthropogenic P was more bioavailable than naturally occurring P, there were higher algal abundances downstream relative to upstream of nutrient point sources at a given P concentration. Neither TP nor soluble reactive P concentrations were indicative of P bio availability. Of the measures studied, epilithic alkaline phosphatase activity was most strongly correlated with algal abundance, most indicative of P bioavailability and thus the most precise indicator of P limitation. Although changes in dissolved inorganic nitrogen (DIN) to P ratios in river water and carbon (C) to P ratios in epilithon were consistent with changes in algal abundance and nutrient limitation, published water DIN to TP and tissue C to P ratio thresholds did not always yield accurate predictions of the type or degree of nutrient limitation. Epilithic N to P ratios and algal growth on nutrient-diffusing substrates were also inexact measures of epilithic nutrient limitation but, unlike other measures, were not strongly correlated with algal abundance. Thus, the predictability of the benthic algal response to anthropogenic nutrient additions in oligotrophic rivers will be improved by using measures indicative of both nutrient limitation and bioavailability.

scholarly journals The light-to-nutrient ratio in alpine lakes: different scenarios of bacterial nutrient limitation and community structure in lakes above and below the treeline

2021 ◽  
Author(s):  
Yaling Su ◽  
Yingxun Du ◽  
Peng Xing
Keyword(s):  
Nutrient Limitation ◽  
Environmental Changes ◽  
Alpine Lakes ◽  
High Light ◽  
Low Light ◽  
Bacterioplankton Community ◽  
P Limitation ◽  
Organic Carbon Concentration ◽  
C Limitation ◽  
Nutrient Conditions

Abstract The light-to-nutrient hypothesis proposes that under high light-to-nutrient conditions, bacteria tend to be limited by phosphorus (P), while under relatively low light-to-nutrient conditions, bacteria are likely driven towards carbon (C) limitation. Exploring whether this light-to-nutrient hypothesis is fitting for alpine lakes has profound implications for predicting the impacts of climatic and environmental changes on the structures and processes of aquatic ecosystems in climate-sensitive regions. We investigated the environmental conditions and bacterioplankton community compositions of 15 high-elevation lakes (7 above and 8 below treeline). High light-to-nutrient conditions (denoted by the reciprocal value of the attenuation coefficient (1/K) to total phosphorus (TP)), high chlorophyll a (Chl a) concentrations, low TP concentrations and low ratios of the dissolved organic carbon concentration to the dissolved total nitrogen concentration (DOC: DTN) were detected in above-treeline lakes. Significant positive correlations between the bacterioplankton community compositions with 1/K:TP ratios and Chl a concentrations indicated that not only high light energy but also nutrient competition between phytoplankton and bacteria might induce P limitation for bacteria. In contrast, low light-to-nutrient conditions and high allochthonous DOC input in below-treeline lakes lessen P limitation and C limitation. The most abundant genus, Polynucleobacter, was significantly enriched and more diverse oligotypes of Polynucleobacter OTUs were identified in the below-treeline lakes, indicating the divergence of niche adaptations among Polynucleobacter oligotypes. The discrepancies in the light-to-P ratio and the components of organic matter between the above-treeline and below-treeline lakes have important implications for the nutrient limitation of bacterioplankton and their community compositions.

Bacterioplankton production, abundance, and nutrient limitation among lakes of the Mackenzie Delta (western Canadian arctic)

2006 ◽  
Vol 63 (4) ◽  
pp. 845-857 ◽  
Author(s):  
Bryan M Spears ◽  
Lance FW Lesack
Keyword(s):  
Nutrient Limitation ◽  
Bacterial Production ◽  
Light Attenuation ◽  
Open Water ◽  
Flood Frequency ◽  
Inorganic Nutrient ◽  
Mackenzie Delta ◽  
Bacterial Productivity ◽  
River Flooding ◽  
Bacterioplankton Production

The effects of nutrient availability and quality of dissolved organic carbon (DOC) on bacterioplankton production were assessed in six lakes with differing frequencies of river flooding. Bacterial productivity, dissolved nutrients, and DOC were tracked weekly throughout the open-water period of 2001. Inorganic nutrient (N and P) enrichment microcosm experiments were conducted to directly assess the effects of DOC quality (i.e., mixtures of colored and noncolored DOC) and inorganic nutrient limitation on bacterial productivity among the lakes. Averaged over the open-water season, both abundance and production of bacterioplankton increased with decreasing flood frequency (R2 = 0.61 and R2 = 0.78, respectively). Reduced bacterial production occurred in frequently flooded lakes, where colored DOC, light attenuation, and phosphate were high but ammonium was low. Bacterial production was greatest in infrequently flooded lakes, where noncolored DOC and ammonium were high but phosphate was low. Bacterial production was enhanced by amendments of inorganic nutrients in duplicate experiments (two-factor analyses of variance). Production was also enhanced in response to higher concentrations of either colored or noncolored DOC following release from inorganic nutrient limitation. Size fractionated (<1 µm versus >1 µm) N-debt and P-debt bioassays typically showed demand for P and release of N by bacteria in all study lakes.

scholarly journals Phytoplankton productivity across prairie saline lakes of the Great Plains (USA): a step toward deciphering patterns through lake classification models

2009 ◽  
Vol 66 (9) ◽  
pp. 1435-1448 ◽  
Author(s):  
Courtney R. Salm ◽  
Jasmine E. Saros ◽  
Sherilyn C. Fritz ◽  
Christopher L. Osburn ◽  
David M. Reineke
Keyword(s):  
Primary Production ◽  
Nutrient Limitation ◽  
Great Plains ◽  
Saline Lakes ◽  
Information Criterion ◽  
The United States ◽  
Northern Great Plains ◽  
Classification Models ◽  
Phytoplankton Productivity ◽  
P Limitation

We investigated patterns of primary production across prairie saline lakes in the central and northern Great Plains of the United States. Based on comparative lake sampling in 2004, seasonal predictors of algal primary productivity were identified within subsets of similar lakes using a combination of Akaike’s information criterion (AIC) and classification and regression trees (CART). These models indicated complex patterns of nutrient limitation by nitrogen (N), phosphorus (P), and iron (Fe) within different lake groups. Nutrient enrichment assays (control, + Fe, + N, + P, + N + P) were performed in spring and summer of 2006 to determine if phytoplankton in selected lakes followed predicted patterns of nutrient limitation. Both the comparative lake sampling and experimental results indicated that N limitation was widespread in these prairie lakes, with evidence for secondary P limitation in certain lakes. In the experiments, iron did not stimulate primary production. Our results suggest that given the diverse geochemical nature of these lakes, classification models that separate saline lakes into subsets may be an effective method for improving predictions of algal production.

scholarly journals Nutrient Limitation and Uptake Rates in Streams and Rivers of the Greater Yellowstone Ecosystem

2013 ◽  
Vol 36 ◽  
pp. 153-159
Author(s):  
Jennifer Tank ◽  
Alexander Reisinger
Keyword(s):  
Water Quality ◽  
Nutrient Limitation ◽  
Water Column ◽  
Nutrient Dynamics ◽  
Nutrient Retention ◽  
Light Limitation ◽  
Small Stream ◽  
Streams And Rivers ◽  
Greater Yellowstone ◽  
Uptake Studies

Nutrient pollution of aquatic ecosystems is a growing concern as the influence of human activities continues to increase on the landscape. Headwater streams have long been shown to process nutrients via the biofilm community growing on the bottom of streams. The growth and activity of these biofilms is often limited by the availability of nitrogen (N), phosphorus (P), or co-limited by both N and P. Although small stream nutrient dynamics are relatively well understood, comparatively little is known about larger, non-wadeable rivers. Biofilms on the river bottom are likely still nutrient limited, but there becomes an increased potential for light limitation as rivers increase in depth. In addition to biofilms on the bottom of rivers, free-living microbial communities suspended in the water column also occur in rivers and process nutrients - a component of nutrient processing largely ignored in streams. In summer 2013 we worked in streams and rivers of the Greater Yellowstone Area (GYA) to establish the nutrient limitation status of minimally-impacted rivers, as well as the role of the water column in processing nutrients as streams increase in size. For both the nutrient limitation and water column uptake studies, we are using the GYA sites in addition to systems from other regions of the US to establish what controls the various aspects of nutrient dynamics in rivers. Our results from the GYA, in addition to Midwest and Southwest US rivers, will provide water quality managers with new strategies for improving water quality downstream, and clarify mechanisms controlling nutrient retention in rivers.

N and P limitation shapes plant-AMF interactions across an aridity gradient

2020 ◽  
Author(s):  
Svenja Stock ◽  
Moritz Köster ◽  
Jens Boy ◽  
Roberto Godoy ◽  
Francisco Nájera ◽  
...  
Keyword(s):  
Nutrient Limitation ◽  
Drought Resistance ◽  
Plant Nutrition ◽  
Water Shortage ◽  
Aridity Gradient ◽  
P Limitation ◽  
Mediterranean Conditions ◽  
Mediterranean Woodland ◽  
Semiarid Conditions

&lt;p&gt;Arbuscular mycorrhizal fungi (AMF) are important partners in plant nutrition, as they increase the range to scavenge for nutrients and can access resources otherwise occlude for plants. Under water shortage, when mobility of nutrients in soil is limited, AMF are especially important to acquire resources and can modulate plant drought resistance. Strategies of plants to cope with water and nutrient restrictions are shaped by the intensity of aridity. To investigate the effect of aridity on plant-AMF associations regarding drought resistance and plant nutrient acquisition, a &lt;sup&gt;13&lt;/sup&gt;CO&lt;sub&gt;2&lt;/sub&gt; pulse labeling was conducted across an aridity gradient. In a semiarid shrubland (66 mm a&lt;sup&gt;-1&lt;/sup&gt;), a Mediterranean woodland (367 mm a&lt;sup&gt;-1&lt;/sup&gt;), and a humid temperate forest (1500 mm a&lt;sup&gt;-1&lt;/sup&gt;), root and soil samples were taken from 0-10 cm and 20-30 cm soil depth before labeling and at 1 day, 3 days, and 14 days after labeling. Carbon (C), nitrogen (N), and phosphorus (P) stocks as well as AMF root colonization, extraradical AMF biomass (phospho- and neutral lipid fatty acids (PLFA and NLFA) 16:1w5c), specific root length (SRL), and root tissue density (RTD) were measured. Plant C investment into AMF and roots was determined by the &lt;sup&gt;13&lt;/sup&gt;C incorporation in 16:1w5c (PLFA and NLFA) and root tissue, respectively. Soil C:N:P stoichiometry indicated a N and P limitation under humid conditions and a P limitation in the topsoil under Mediterranean conditions. N stocks were highest in the Mediterranean woodland. A strong correlation of the AMF storage compound NLFA 16:1w5c to C:P ratio under semiarid conditions pointed to a P limitation of AMF, likely resulting from low P mobility in dry and alkaline soils. With increasing aridity, the AMF abundance in root (and soil) decreased from 45% to 20% root area. &lt;sup&gt;13&lt;/sup&gt;C incorporation in PLFA 16:1w5c was similar across sites, while relative AMF abundance in topsoil (PLFA 16:1w5c:SOC) was slightly higher under semiarid and humid than under Mediterranean conditions, pointing to the importance of AMF for plant nutrition under nutrient limitation. Additionally, PLFA 16:1w5c contents in soil were higher with lower P availability in each site, underlining the role of AMF to supply P for plants under P deficiency. Under humid conditions (with strong N and P limitation) and semiarid conditions (with strong water limitation), root AMF colonization increased with lower N availability, displaying the role of AMF for plant N nutrition under nutrient and/or water shortage. Under humid and Mediterranean conditions, SRL decreased (0.5 and 0.3 times, respectively) and RTD increased (1.9 and 1.7 times, respectively) with depth, indicating a drought tolerance strategy of plants to sustain water shortage. Under semiarid conditions, SRL increased with depth (2.3 times), while RTD was consistently high, suggesting an increasing proportion of long-living fine roots with depth as scavenging agents for water. These relations point to a drought avoidance strategy of plants as adaptation to long-term water limitation. Under strong nutrient limitation, as under humid and semiarid conditions, AMF are crucial to sustain plant nutrition and to enhance plant resistance to water shortage.&lt;/p&gt;

scholarly journals Microbial nutrient limitation in arctic lakes in a permafrost landscape of southwest Greenland

2015 ◽  
Vol 12 (14) ◽  
pp. 11863-11890
Author(s):  
B. Burpee ◽  
J. E. Saros ◽  
R. M. Northington ◽  
K. S. Simon
Keyword(s):  
Nutrient Limitation ◽  
Enzyme Activities ◽  
Arctic Lakes ◽  
The Arctic ◽  
Nutrient Concentrations ◽  
Nutrient Inputs ◽  
P Limitation ◽  
Microbial P ◽  
Microbial Nutrient Limitation ◽  
Southwest Greenland

Abstract. Permafrost is degrading across regions of the Arctic, which can lead to increases in nutrient concentrations in surface freshwaters. The oligotrophic state of many arctic lakes suggests that enhanced nutrient inputs may have important effects on these systems, but little is known about microbial nutrient limitation patterns in these lakes. We investigated microbial extracellular enzyme activities (EEAs) to infer seasonal nutrient dynamics and limitation across 24 lakes in southwest Greenland during summer (June and July). From early to late summer, enzyme activities that indicate microbial carbon (C), nitrogen (N), and phosphorus (P) demand increased in both the epilimnia and hypolimnia by 74 % on average. Microbial investment in P acquisition was generally higher than that for N. Interactions among EEAs indicated that bacteria were primarily P limited. Dissolved organic matter (DOM, measured as dissolved organic carbon) was strongly and positively correlated with microbial P demand (R2 = 0.84 in July), while there were no relationships between DOM and microbial N demand. Microbial P limitation in June epilimnia (R2 = 0.67) and July hypolimnia (R2 = 0.57) increased with DOM concentration. The consistency of microbial P limitation from June to July was related to the amount of DOM present, with some low DOM lakes becoming N-limited in July. Our results suggest that future changes in P or DOM inputs to these lakes are likely to alter microbial nutrient limitation patterns.

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