Seasonal Variation of Potential Nutrient Limitation to Chlorophyll Production in Southern Lake Huron

1981 ◽  
Vol 38 (1) ◽  
pp. 1-9 ◽  
Author(s):  
C. Kwei Lin ◽  
Claire L. Schelske
Keyword(s):  
Trace Metals ◽  
Nutrient Limitation ◽  
Surface Waters ◽  
Lake Huron ◽  
Nutrient Additions ◽  
Limiting Nutrients ◽  
Complete Treatment ◽  
Limiting Nutrient ◽  
Chlorophyll Production ◽  
Experimental Treatments

Potential nutrient limitation to chlorophyll production in surface waters of southern Lake Huron was assayed monthly from April to December 1975. Natural phytoplankton assemblage responses to nutrient enrichment were determined from chlorophyll production in laboratory incubations under seasonally varied light and temperature conditions. Experimental treatments included a complete treatment containing P, N, Si, EDTA, vitamins, and trace metals; treatments with deletions from the complete treatment; complete treatments with different P concentrations; and treatments with single nutrient additions. Effects were most pronounced during summer and fall when P, EDTA, FeEDTA, vitamins, and Si were added simultaneously. The intensity of the effect resulting from additions of phosphorus and other nutrients varied seasonally. Individual additions of EDTA, N, and Si had little effect as did deletion of N from the complete treatment. Addition of P alone resulted in limited growth. Deletion of phosphorus from the complete enrichment, however, reduced growth drastically during most experimental periods. In the complete treatment the minimum levels of P that caused significant chlorophyll production ranged from 1 to 3 μg L−1. Chelate (EDTA), chelated iron, and vitamins were important secondary limiting nutrients during the summer months. There was a small effect due to silica in July, September, and October, and no indication of deficiency in trace metals. Trace metals, when deleted, frequently produced greater chlorophyll than the complete treatment, but growth was sharply reduced by deletion of trace metals and EDTA combined. The results clearly demonstrate that large increases in chlorophyll production in southern Lake Huron require simultaneous additions of the primary limiting nutrient (P) and secondary limiting nutrients (EDTA, FeEDTA, and vitamins) which vary seasonally.Key words: chlorophyll, eutrophication, micronutrients, phosphorus, phytoplankton

Identifying Sources of Sulfate Aerosols Reaching Whiteface Mountain, NY

1985 ◽  
Vol 43 ◽  
pp. 98-101
Author(s):  
James S. Webber
Keyword(s):  
Trace Metals ◽  
Acid Deposition ◽  
Surface Waters ◽  
Dry Deposition ◽  
Coal Combustion ◽  
Public Awareness ◽  
Sulfate Aerosols ◽  
Wet And Dry Deposition ◽  
Whiteface Mountain ◽  
Toxic Trace Metals

INTRODUCTION“Acid rain” and “acid deposition” are terms no longer confined to the lexicon of atmospheric scientists and 1imnologists. Public awareness of and concern over this phenomenon, particularly as it affects acid-sensitive regions of North America, have increased dramatically in the last five years. Temperate ecosystems are suffering from decreased pH caused by acid deposition. Human health may be directly affected by respirable sulfates and by the increased solubility of toxic trace metals in acidified waters. Even man's monuments are deteriorating as airborne acids etch metal and stone features.Sulfates account for about two thirds of airborne acids with wet and dry deposition contributing equally to acids reaching surface waters or ground. The industrial Midwest is widely assumed to be the source of most sulfates reaching the acid-sensitive Northeast since S02 emitted as a byproduct of coal combustion in the Midwest dwarfs S02 emitted from all sources in the Northeast.

Production of Rhamnolipid Biosurfactant from Fed Batch Culture by Pseudomonas aeruginosa using Multiple Substrates

2020 ◽  
Vol 16 (6) ◽  
pp. 928-933
Author(s):  
Jujjavarapu S. Eswari
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Batch Process ◽  
Time Interval ◽  
Fed Batch ◽  
Multiple Substrates ◽  
Surface Active Agents ◽  
Limiting Nutrients ◽  
Limiting Nutrient ◽  
Surface Active ◽  
Rhamnolipid Biosurfactant

Objective: Biosurfactants are the surface active agents which are used for the reduction of surface and interfacial tensions of liquids. Rhamnolipids are the surfactants produced by Pseudomonas aeruginosa. It requires minimum nutrition for its growth as it can also grow in distilled water. The rhamnolipids produced by Pseudomonas aeruginosa are extra-cellular glycolipids consisting of L-rhamnose and 3-hydroxyalkanoic acid. Methods: The fed-batch method for the rhamnolipid production is considered in this study to know the influence of the carbon, nitrogen, phosphorous substrates as growth-limiting nutrients. Pulse feeding is employed for limiting nutrient addition at particular time interval to obtain maximum rhamnolipid formation from Pseudomonas aeruginosa compared with the batch process. Results: Out of 3 fed batch strategies constant glucose fed batch strategy shows best and gave maximum rhamnolipid concentration of 0.134 g/l.

scholarly journals Edge-of-Field Technologies for Phosphorus Retention from Agricultural Drainage Discharge

2020 ◽  
Vol 10 (2) ◽  
pp. 634 ◽  
Author(s):  
Lipe Renato Dantas Mendes
Keyword(s):  
Surface Waters ◽  
Organic Phosphorus ◽  
Freshwater Ecosystems ◽  
Phosphorus Retention ◽  
Buffer Strips ◽  
Large Variability ◽  
Agricultural Catchments ◽  
Limiting Nutrient ◽  
Phosphorus Form ◽  
Subsurface Drains

Agriculture is often responsible for the eutrophication of surface waters due to the loss of phosphorus—a normally limiting nutrient in freshwater ecosystems. Tile-drained agricultural catchments tend to increase this problem by accelerating the transport of phosphorus through subsurface drains both in dissolved (reactive and organic phosphorus) and particulate (particle-bound phosphorus) forms. The reduction of excess phosphorus loads from agricultural catchments prior to reaching downstream surface waters is therefore necessary. Edge-of-field technologies have been investigated, developed and implemented in areas with excess phosphorus losses to receive and treat the drainage discharge, when measures at the farm-scale are not able to sufficiently reduce the loads. The implementation of these technologies shall base on the phosphorus dynamics of specific catchments (e.g., phosphorus load and dominant phosphorus form) in order to ensure that local retention goals are met. Widely accepted technologies include constructed wetlands, restored wetlands, vegetated buffer strips and filter materials. These have demonstrated a large variability in the retention of phosphorus, and results from the literature can help targeting specific catchment conditions with suitable technologies. This review provides a comprehensive analysis of the currently used edge-of-field technologies for phosphorus retention in tile-drained catchments, with great focus on performance, application and limitations.

Dissolved and particulate trace metals in surface waters over the Dogger Bank, Central North Sea

1991 ◽  
Vol 22 (5) ◽  
pp. 241-244 ◽  
Author(s):  
Catherine F. Fileman ◽  
M. Althaus ◽  
R.J. Law ◽  
I. Haslam
Keyword(s):  
Trace Metals ◽  
North Sea ◽  
Surface Waters ◽  
Dogger Bank ◽  
Central North Sea

scholarly journals Numerical study of dispersion and hydrodynamic connectivity of near-surface waters in Lake Huron

2012 ◽  
Vol 47 (3-4) ◽  
pp. 238-251 ◽  
Author(s):  
Jun Zhao ◽  
Yerubandi R. Rao ◽  
Jinyu Sheng
Keyword(s):  
Surface Waters ◽  
Numerical Study ◽  
Three Dimensional ◽  
Coastal Region ◽  
Lake Huron ◽  
Physical Parameters ◽  
Three Dimensional Model ◽  
Near Surface ◽  
Georgian Bay ◽  
Main Lake

A nested-grid hydrodynamic modeling system is used to examine the circulation and dispersion in Lake Huron and adjacent areas with specific attention to physical parameters pertinent to the estimation of hydrodynamic connectivity of near-surface waters. The nested system is forced by monthly mean surface heat flux and 12-hourly wind stress computed from wind speeds extracted from the National Centers for Environmental Prediction of the National Center for Atmospheric Research (NCEP/NCAR) 40-year reanalysis data. The three-dimensional model currents are used to calculate the retention and dispersion of conservative, near-surface particles carried by the currents. The near-surface dispersion is relatively low in Saginaw Bay, eastern Georgian Bay and the eastern North Channel; and relatively high over the western part of the main lake and the coastal region of south Lake Huron. The hydrodynamic connectivity in the surface water and connectivity matrices are calculated from particle movements carried passively by model currents superposed by a random walk process. The model results demonstrate that the hydrodynamic connectivity in the North Channel and Georgian Bay (ranging from 0.9 to 2.2%) is much weaker than those in the main lake (5.3 to 21.9%).

Sign in / Sign up

Export Citation Format

Share Document