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.

Linkage between Epilithic Algal Growth and Water Column Nutrients in Softwater Lakes

1992 ◽  
Vol 49 (8) ◽  
pp. 1641-1649 ◽  
Author(s):  
G. Winfield Fairchild ◽  
John W. Sherman
Keyword(s):  
Nutrient Limitation ◽  
Water Column ◽  
Chlorophyll A ◽  
Standing Crop ◽  
Crop Production ◽  
Dissolved Inorganic Carbon ◽  
Inorganic Nitrogen ◽  
Algal Growth ◽  
Acidic Lakes ◽  
Softwater Lakes

We examined the dependence of epilithic algal standing crop, production, and nutrient limitation upon water column nutrients in 12 softwater lakes of northeastern Pennsylvania. Elevated dissolved inorganic nitrogen accompanied low dissolved inorganic carbon in the more acidic lakes, while P varied little within the study area. The growth of epilithon on clay flower pot substrata diffusing combinations of N (NaNO3), P (Na2HPO4), and C (NaHCO3) was compared with growth on control substrata to evaluate which of the three nutrients limited growth in each lake. Standing crop accrual as chlorophyll a on control substrata averaged 0.8 μg/cm2, with little variation among lakes. Nutrient limitation of growth, however, was strongly related to lake alkalinity. Chlorophyll a was typically enhanced by N and/or P only in lakes with alkalinity greater than ~100 μeq/L and responded strongly to C enrichment in the two most acidic lakes. Combined addition of all three nutrients produced the largest chlorophyll a accrual in all 12 lakes. Invertebrate grazer biomass, dominated by chironomids in the more acidic lakes and by snails at higher alkalinity, was negatively related to chlorophyll a on these NPC substrata (r = −0.57, p = 0.05) and may have reduced algal standing crop well below nutrient-sustainable levels in some lakes.

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.

Nutrient limitation on algal growth in the eau gallie river

1974 ◽  
Vol 12 (5) ◽  
pp. 587-593
Author(s):  
R. G. Hoffman ◽  
J. A. Lasater ◽  
L. W. Houk
Keyword(s):  
Nutrient Limitation ◽  
Algal Growth

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.

Nutrient pollution at the lower reaches of Mediterranean coastal rivers in Israel

2000 ◽  
Vol 42 (1-2) ◽  
pp. 147-152 ◽  
Author(s):  
B. Herut ◽  
N. Kress ◽  
H. Hornung
Keyword(s):  
Inorganic Nitrogen ◽  
Agricultural Runoff ◽  
Point Sources ◽  
Industrial Wastes ◽  
Nutrient Concentrations ◽  
Contamination Level ◽  
Nutrient Load ◽  
Nutrient Loads ◽  
Discharge Data ◽  
Coastal Rivers

This study represents the first attempt to evaluate the nutrient load introduced into the coastal waters by the rivers along the Mediterranean coast of Israel. Measurements of nutrient concentrations (phosphate, ammonium, nitrate, nitrite, silicic acid) at two or three stations along the lower river reaches (11 rivers) were carried out annually from 1990 up to 1998. Combining the nutrient concentrations with the monthly riverine discharges we assessed the nutrient load. In general, most of the coastal rivers contain high nutrient contamination level, compared to the criteria adopted by NOAA (USA) for coastal river estuaries. The high degree of contamination is attributed to extreme low natural flow combined with the discharge of domestic and industrial wastes, and with agriculture runoff. In terms of nutrient concentrations, the Kishon River is the most polluted, followed by the Soreq, Poleg and Alexander Rivers. The preliminary estimate is that the coastal rivers transport between ~2000 to 6000 tons of dissolved inorganic nitrogen (DIN) and between ~250–800 tons of dissolved inorganic phosphorus (DIP) to the sea. An additional 3500 and 3000 tons of DIN and DIP, respectively, are supplied through the Kishon River. The load of the Poleg River is unknown (no discharge data) but expected to be significant based on nutrient concentration measured. The total load of the coastal rivers constitutes a major component among the other land-base point sources such as the Gush Dan outfall. Our estimate probably represents minimal values, as it does not include diffused input of agricultural runoff nor the riverine particulate and dissolved organic nutrient loads (which are unknown).

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.

scholarly journals Patterns and Drivers of Extracellular Enzyme Activity in New Zealand Glacier-Fed Streams

2020 ◽  
Vol 11 ◽  
Author(s):  
Tyler J. Kohler ◽  
Hannes Peter ◽  
Stilianos Fodelianakis ◽  
Paraskevi Pramateftaki ◽  
Michail Styllas ◽  
...  
Keyword(s):  
Climate Change ◽  
Extracellular Polymeric Substances ◽  
Extracellular Enzymes ◽  
Inorganic Nitrogen ◽  
Extracellular Enzyme ◽  
Microbial Life ◽  
Mountain Glaciers ◽  
P Limitation ◽  
Habitat Template ◽  
N Demand

Glacier-fed streams (GFSs) exhibit near-freezing temperatures, variable flows, and often high turbidities. Currently, the rapid shrinkage of mountain glaciers is altering the delivery of meltwater, solutes, and particulate matter to GFSs, with unknown consequences for their ecology. Benthic biofilms dominate microbial life in GFSs, and play a major role in their biogeochemical cycling. Mineralization is likely an important process for microbes to meet elemental budgets in these systems due to commonly oligotrophic conditions, and extracellular enzymes retained within the biofilm enable the degradation of organic matter and acquisition of carbon (C), nitrogen (N), and phosphorus (P). The measurement and comparison of these extracellular enzyme activities (EEA) can in turn provide insight into microbial elemental acquisition effort relative to environmental availability. To better understand how benthic biofilm communities meet resource demands, and how this might shift as glaciers vanish under climate change, we investigated biofilm EEA in 20 GFSs varying in glacier influence from New Zealand’s Southern Alps. Using turbidity and distance to the glacier snout normalized for glacier size as proxies for glacier influence, we found that bacterial abundance (BA), chlorophyll a (Chl a), extracellular polymeric substances (EPS), and total EEA per gram of sediment increased with decreasing glacier influence. Yet, when normalized by BA, EPS decreased with decreasing glacier influence, Chl a still increased, and there was no relationship with total EEA. Based on EEA ratios, we found that the majority of GFS microbial communities were N-limited, with a few streams of different underlying bedrock geology exhibiting P-limitation. Cell-specific C-acquiring EEA was positively related to the ratio of Chl a to BA, presumably reflecting the utilization of algal exudates. Meanwhile, cell-specific N-acquiring EEA were positively correlated with the concentration of dissolved inorganic nitrogen (DIN), and both N- and P-acquiring EEA increased with greater cell-specific EPS. Overall, our results reveal greater glacier influence to be negatively related to GFS biofilm biomass parameters, and generally associated with greater microbial N demand. These results help to illuminate the ecology of GFS biofilms, along with their biogeochemical response to a shifting habitat template with ongoing climate change.

scholarly journals Occurrence of Escherichia coli and Enterococci in Cladophora (Chlorophyta) in Nearshore Water and Beach Sand of Lake Michigan

2003 ◽  
Vol 69 (8) ◽  
pp. 4714-4719 ◽  
Author(s):  
Richard L. Whitman ◽  
Dawn A. Shively ◽  
Heather Pawlik ◽  
Meredith B. Nevers ◽  
Muruleedhara N. Byappanahalli
Keyword(s):  
Escherichia Coli ◽  
Lake Michigan ◽  
Dry Weight ◽  
Point Sources ◽  
Indicator Bacteria ◽  
Beach Sand ◽  
Cladophora Glomerata ◽  
Strongly Correlated ◽  
Fecal Indicator ◽  
E Coli

ABSTRACT Each summer, the nuisance green alga Cladophora (mostly Cladophora glomerata) amasses along Lake Michigan beaches, creating nearshore anoxia and unsightly, malodorous mats that can attract problem animals and detract from visitor enjoyment. Traditionally, elevated counts of Escherichia coli are presumed to indicate the presence of sewage, mostly derived from nearby point sources. The relationship between fecal indicator bacteria and Cladophora remains essentially unstudied. This investigation describes the local and regional density of Escherichia coli and enterococci in Cladophora mats along beaches in the four states (Wisconsin, Illinois, Indiana, and Michigan) bordering Lake Michigan. Samples of Cladophora strands collected from 10 beaches (n = 41) were assayed for concentrations of E. coli and enterococci during the summer of 2002. Both E. coli and enterococci were ubiquitous (up to 97% occurrence), with overall log mean densities (± standard errors) of 5.3 (± 4.8) and 4.8 (± 4.5) per g (dry weight). E. coli and enterococci were strongly correlated in southern Lake Michigan beaches (P < 0.001, R 2 = 0.73, n = 17) but not in northern beaches (P = 0.892, n = 16). Both E. coli and enterococci survived for over 6 months in sun-dried Cladophora mats stored at 4°C; the residual bacteria in the dried alga readily grew upon rehydration. These findings suggest that Cladophora amassing along the beaches of Lake Michigan may be an important environmental source of indicator bacteria and call into question the reliability of E. coli and enterococci as indicators of water quality for freshwater recreational beaches.

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;

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