Effects of acidity and doc on phytoplankton community structure and production in three acid lakes (Nova Scotia)

Phytoplankton community structure varied between the three lakes and between years within lakes. The Beaverskin Lake phytoplankton community was dominated by cyanophytes and chlorophytes in the summer and chrysophytes in the winter. Kejimkujik Lake was dominated by bacillariophytes in the summer of 1979 but no single group dominated in 1980 or 1981. Pebbleloggitch Lake phytoplankton consisted mainly of chlorophytes in 1979 but low biomass and no dominant groups characterized this lake during the growing season of 1980. Daily integral planktonic primary production measured simultaneously in the three lakes showed that in both years annual planktonic primary production was highest in the clear water lake, Beaverskin Lake, which also had lower dissolved organic carbon (DOC) concentration compared to the two dystrophic lakes. In the clear water lake annual production was similar between years but in the two colored lakes annual production was 40% higher in the second year. The observed increases in annual production between years in the colored lakes were largely due to changes in euphotic depth resulting from variations in hydrology and DOC export from the lake catchments. Lower discharges in the colored lakes in 1980 were accompanied by significantly lower in lake DOC concentrations, water color, light extinction coefficients and increased euphotic depth. Similar changes in discharge accompanied by lower DOC concentration in the clear water lake did not produce significant changes in water color, light extinction coefficient nor annual production between years. Rates of primary production at light optimum (P-max) were consistently higher in the most colored, acidic lake indicating that relatively high rates of autotrophic production will occur under acidic conditions if nutrient supply is maintained.     

A Comparison of the Temporally Integrated Monitoring of Ecosystems and Adirondack Long-Term Monitoring Programs in the Adirondack Mountain Region of New York

This paper compares lake chemistry in the Adirondack region of New York measured by the Temporally Integrated Monitoring of Ecosystems (TIME) and Adirondack Long-Term Monitoring (ALTM) programs by examining the data from six lakes common to both programs. Both programs were initiated in the early 1990s to track the efficacy of emission reduction policies and to assess the full impacts of acid deposition on surface water chemistry. They now serve to inform on the emerging chemical recovery of these waters. The Adirondack TIME program utilizes a probability-based approach to assess chronic acidification in a population of lakes using one summer sample per year. The ALTM attempts to track changes in both chronic and episodic acidification across a gradient of lake types using monthly samples. The ALTM project has two important attributes that contrast with the TIME program in the Adirondacks: higher temporal resolution (monthly versus once during the summer or fall) and speciation of aluminum. In particular, the ALTM program provides inorganic monomeric aluminum (Al_IM), the fraction of Al that is most toxic. The monthly sampling of the ALTM program includes the spring snowmelt period when acid-neutralizing capacity and pH are near their lowest and Al levels are near their highest. We compare chemistry trends (1992?C2008) for sulfate, nitrate, base cations, dissolved organic carbon, hydrogen ion, acid neutralizing capacity, and Al for the six lakes common to both programs. We also compare relatively high springtime Al_IM concentrations from the ALTM with relatively low summertime total Al concentrations from the TIME, showing that the ALTM program provides a more biologically relevant indicator of the effects of acid deposition, illustrating the value of the complementary monitoring efforts in the Adirondack region.     

Diatom-inferred pH history of Kejimkujik Lake,Nova Scotia: A reinterpretation

A reanalysis of the diatom-inferred pH profile from a sediment core collected in 1980 from Kejimkujik Lake has been made in the light of improved techniques and ecological information. Using Index B calibrated for lakes in Atlantic Canada, the lake pH was 4.6 to 4.7 before anthropogenic disturbances in the watershed began ca. 1850. These disturbances had little immediate impact on pH, but minima of pH 4.5 were evident in the period 1916 to 1950. A diatom-inferred pH of 4.75 in the surface sediments compares with a measured pH of 4.96 in 1980. Disturbances in the watershed since ca. 1850 resulted in a large increase in a form of Asterionella ralfsii, a diatom associated with colored, humic water. A decline in this diatom since 1950 and an increase in taxa less typical of humic water is consistent with the hypothesis of loss of organic matter accompanying acidification from acidic precipitation.     

Longitudinal trends in pH and aluminum chemistry of the Coxing Kill,Ulster County,New York

The purpose of this work was to characterize the Al chemistry along the longitudinal pH gradient of the Coxing Kill and thereby provide a basis for an in depth study of aluminum chemistry and transport as a function of pH. Water samples were collected along the pH gradient and analyzed for monomeric Al species, strong acid anions, base cations, ammonium, dissolved organic C and dissolved silica. Inorganic monomeric Al, organic momonmeric Al and dissolved organic C decreased in concentration as the stream's drainage area and pH increased. The ratio of organic to inorganic monomeric Al and the concentration of all other species increased with increasing pH. An abrupt change in stream chemistry occurred in conjunction with the gradual changes expected for a low order stream draining an acid sensitive watershed impacted by acid deposition. This abrupt change partially resulted from geological characteristics of the watershed.     

Characteristics of Monomeric Al Concentration in An Acidified River

The Kusurisambetsu River is a tributary of the Noboribetsu River. These rivers flow through Hokkaido Prefecture, Japan. Because the upper reaches of the river are acidified by a caldera lake and basin, the river water contains aluminum in high concentration, together with iron and sulfate. The drainage area at the lower reaches is not acidified. Therefore, the acidified water of the river is neutralized by the alkalinity of water from the drainage area. The water at the mouth is neutral in pH, although about 1 mg/L of aluminum is detected. Heavy rainfall occurred in Autumn 1993, and many adult salmon were killed at the lower reaches of the river. This prompted study of the neutralization process of river water, the Al concentration change, and the influence of rainfall. Determination of Al found total Al concentration to be roughly constant at the mouth of the Noboribetsu River. However, the concentration of monomeric Al varied with pH, which varied according to rainfall and flow volume. Monomeric Al showed a minimum concentration of roughly pH 6.0. At pH of greater than 6.0, the presence of some kinds of polymeric Al is determined by filtration fraction. This suggests that the death of salmon is caused by monomeric Al when conditions are acidic. Liming test of the river water confirmed that the monomeric Al that was toxic under acidic conditions became non-toxic under alkaline conditions.     

Interpretation of Mercury Concentrations in Eight Headwater Lakes in Kejimkujik National Park, (Nova Scotia, Canada) by Use of a Geographic Information System and Statistical Techniques

The concentration of mercury in eight headwater lakes in Kejimkujik National Park correlated positively with total organic carbon, total nitrogens, aluminum, iron and sodium andnegatively with pH and alkalinity (Gran). Annual average mercuryyield of the lakes correlated positively with basin area to lakesurface area ratio, and watershed areas underlain by granite bedrock and glacial deposits and negatively with greywacke bedrock. Principal component analysis indicated that first threecomponents account for 80% of the total variance in the data.The components were related to physiography and geology of the watershed, hardness of water, and atmospheric washouts of longrange transported acidic pollutants and dust particles. Mercuryin the lake waters was associated with the physiography and geology of the watershed. Total organic carbon, aluminum and iron were good predictors of mercury concentration in the lakewaters as were the basin area to lake surface area ratio, and basin areas underlain by granite bedrock, and Halifax slate forthe lake mercury yield. The results showed that transport of mercury from the watershed is a major source of mercury in thestudy lakes.     

Dissolved organic matter sorption by mineral constituents of subsoil clay fractions

The retention of dissolved organic matter in soils is mainly attributed to interactions with the clay fraction. Yet, it is unclear to which extent certain clay‐sized soil constituents contribute to the sorption of dissolved organic matter. In order to identify the mineral constituents controlling the sorption of dissolved organic matter, we carried out experiments on bulk samples and differently pretreated clay‐size separates (untreated, organic matter oxidation with H₂O₂, and organic matter oxidation with H₂O₂ + extraction of Al and Fe oxides) from subsoil horizons of four Inceptisols and one Alfisol. The untreated clay separates of the subsoils sorbed 85 to 95% of the dissolved organic matter the whole soil sorbed. The sorption of the clay fraction increased when indigenous organic matter was oxidized by H₂O₂. Subsequent extraction of Al and Fe oxides/hydroxides caused a sharp decrease of the sorption of dissolved organic matter. This indicated that these oxides/hydroxides in the clay fraction were the main sorbents of dissolved organic matter of the investigated soils. Moreover, the coverage of these sorbents with organic matter reduced the amount of binding sites available for further sorption. The non‐expandable layer silicates, which dominated the investigated clay fractions, exhibited a weak sorption of dissolved organic matter. Whole soils and untreated clay fractions favored the sorption of ”︁hydrophobic” dissolved organic matter. The removal of oxides/hydroxides reduced the sorption of the lignin‐derived ”︁hydrophobic” dissolved organic matter onto the remaining layer silicates stronger than that of ”︁hydrophilic” dissolved organic matter.     

Responses of atlantic salmon (Salmo salar) alevins to dissolved organic carbon and dissolved aluminum at low pH

Mortality of Atlantic salmon alevins in solutions containing Al and dissolved organic anions (both synthetic and natural) was correlated with Al accumulation in alevin tissues. Both mortality and accumulation could be related to the concentration differences between Al and organic anions. Mortality and body accumulation of Al both increased dramatically as total Al concentrations increasingly exceeded organic anion concentrations. Alevin growth and yolk utilization were both less rapid at inorganic monomeric Al concentrations exceeding 2 μM (50 μg L^-1). The acidic fractions of dissolved organic matter (DOM) are more effective in protecting alevins against Al toxicity than are the neutral and basic fractions. Ambient inorganic monomeric Al is probably not toxic to salmon alevins in acidic Nova Scotian streams, even during snow-melt.     

Temporal Variations of Aluminium Fractions in Streams in the Delsbo Area, Central Sweden

Stream waters were sampled weekly during spring and monthly during summer and autumn in 1998. The streams are more or less acidified, and some have been treated with lime. The aluminium fractions (total monomeric Al, organic monomeric Al, inorganic monomeric Al) were determined colourimetrically with pyrocatechol violet combined with cation exchange using Continuous Flow Analysis (Autoanalyzer I). The levels of inorganic monomeric aluminium varied substantially, between <3 to 271 µg/l. The levels were higher in untreated than in limed waters and twice as high in the most humic waters as in less humic waters. The importance of aluminium mobilisation from the catchments was obvious, with higher aluminium concentrations in surface runoff (unbalanced stream waters) compared to lake outlets (balanced and precipitated lake water). The highest mean levels were measured at spring, whereas the highest single peaks occurred during summer. Inorganic monomeric and total monomeric aluminium was best correlated to ion ratio and pH whereas acid soluble aluminium and organic monomeric aluminium was best correlated to TOC, water colour and iron.     

Influence of Natural Organic Matter (NOM) on the Speciation of Aluminum during Water Treatment

Natural organic matter (NOM) is a term collectively used to describe the complex matrix of organic material present in natural waters. The impact of NOM on the speciation of aluminum at Buffalo Pound water treatment plant was evaluated in the present study using fulvic acid. The first stage of the study was to conduct aluminum (Al) speciation experiments (using background dissolved organic carbon levels present in the raw water) at the pilot scale water treatment plant located within the main plant changing the aluminum sulfate (alum) dose from 68 mg L^-1 (yearly average dose of the main plant) to 34 mg L^-1. The second stage of the study was to conduct jar tests at various alum/DOC ratios. Pilot scale speciation study showed that when the alum/DOC ratio was 5.3, most of the total aluminum in the filtered water was in the form of particulate aluminum. Such an increased particulate aluminum level did not increase the finished water turbidity. Soluble organic aluminum also increased compared to the level in raw water when the alum/DOC ratio was 5.3. Al speciation study conducted during jar testing showed that organically bound aluminum increased from 8 μg L^-1 (raw water) to 15 μg L^-1 in the finishedwater when the alum/DOC = 1.37. Jar test results also showed that an alum/DOC of at least 7.3 should be maintained in the main plant in order to meet the proposed operating guidelines of 100 μg L^-1 of total aluminum by Health Canada given the conditions that finished water soluble aluminum levels may be in the range of 35–40 μg L^-1.     

Chemical effects of spring and summer alum additions to a small,Northwestern Ontario Lake

Aluminum was added as aluminum sulfate (alum) to Lake 114, a small, shallow lake of the Experimental Lakes Area, northwestern Ontario, in spring and summer point-source additions. Aluminum and H⁺ gradients were established during the additions, with high Al and low pH (about 1000 μg L^?1 Al, pH 4.7) near the alum sources, and background conditions (< 50 μg L^?1 Al, pH 5.7) further from the sources. Approximately 80% of the added Al was lost from the water column in two weeks. Phosphorus concentrations remained unchanged during the additions, whereas lake alkalinity decreased and sulfate increased close to the sources. Dissolved organic carbon (DOC) concentrations decreased slightly (from 540 μM L^?1 to about 500 μM L^?1) near the alum source during the summer addition.     

天目湖水体与沉积物中营养盐时空分布及成因

采用现场监测及实验室分析方法,2006年对天目湖水体和沉积物营养盐等进行了调查。结果发现,天目湖水体中营养盐浓度影响最大的是上游流域输人,冬季天目湖上游输入的颗粒物是导致水体营养盐尤其是TN水平升高的主要因素;而在夏季,水体中营养盐以溶解态为主,天目湖的营养类型是磷限制。表层沉积物营养盐含量最高的点位是下游靠近大坝取水口附近,表层沉积物N、P含量明显高于其下各层,尤其对于营养盐含量较高的点位。研究表明,作为一个兼顾饮用水源地和旅游功能的水库,上游区流域综合保护、水库渔业调控及旅游活动的进一步规范是控制天目湖富营养化的关键。     

The relationship between dissolved organic matter and percolation water chemistry in northern Finland

The aim of this study was to investigate the relationship between dissolved organic matter and chemical constituents of percolation water collected at 5, 20 and 40 cm depths from 13 ionbalance sampling plots located along lines extending through Finnish Lapland from Cu-Ni smelters in the Kola Peninsula, Russia. All the monitoring plots have as uniform as possible stand and site characteristics. The plots were located in Scots pine stands on dry and dryish sites with genetic horizons characteristic of Fe-humus podsols. The soil type on most of the sites was sorted fine sand or sand. Significant positive correlations were found between dissolved organic matter (DOM) and total dissolved Al concentrations at 5 and 20 cm, but not at 40 cm. A significant negative correlation was found between DOM and pH at 5 cm, but not at 20 or 40 cm. The anion deficit was positively correlated with DOM at 5 cm in the percolation water. Organic matter thus plays an important role as an anioh in percolation water, and regulates water pH in the surface soil. A high proportion of dissolved Al was in the form of organic complexes. Total dissolved Al levels were well below the toxic limits for pine.     

Geochemical Mobility and Bioavailability of Heavy Metals in a Lake Affected by Acid Mine Drainage: Lake Hope, Vinton County, Ohio

Sandy Run (Vinton County, southeastern Ohio, USA) is a stream receiving acid mine drainage (AMD) from an abandoned coal mine complex. This stream has been dammed to form Lake Hope. The heavy metal composition of waters (benthic and pore), sediments, and macroinvertebrates in the lake reservoir sediments were analyzed. Lake waters contained Mn as the heavy metal present in higher concentrations followed by Fe, Al, and Zn. Depletion of Fe and Al occurred from precipitation of less soluble Fe and Al oxides and hydroxides along Sandy Run before entering the lake, producing a high Mn water input into the reservoir. Concentrations of heavy metals in the sediments increased toward the dam area. Sequential extraction of metals in the sediments showed that the highest fractions of metals corresponded to the detrital fraction or eroded material from the watershed and metals associated with iron and manganese hydroxides. Heavy metals in the organic sediment fraction were low. Heavy metals from the AMD source, as well as sediments rich in heavy metals eroded from the watershed, were transported to the downstream dam area and stored at the bottom, producing the observed chemistry. Heavy metals in benthic waters also were sourced from the diffusion of ions from sediments and lake waters as variation in pH and redox conditions determined the flux at the sediment–water interface. Metal concentrations were measured within two deposit feeders, oligochaetes and chironomids, and compared to trends in physical metal concentration across the lake. For the four heavy metals with higher concentration in both benthic animals, the concentrations followed the trend: Fe?>?Al?>?Mn?>?Zn, which were similar to the bioavailable metals in the sediments rather than the pore or the benthic water where Mn was the most abundant heavy metal. Ingestion of sediment, not exposure to pore or benthic waters, appeared to be the main transfer mechanism for metals into the biota. Trends and patterns in animal metal concentrations across the lake were probably a complex process controlled by metabolic needs and metallic regulation and tolerance. Even when Mn was the highest concentration heavy metal in the pore waters, it was the lowest to bioconcentrate in the organisms. In comparison, Cd, the lowest concentration metal in the sediments, presented one of the highest bioaccumulation factors.     

Al(III)-binding properties at the molecular level of soil DOM subjected to long-term manuring

Journal of Soils and Sediments - Advanced knowledge of the binding of dissolved organic matter (DOM) with aluminum (Al) ions is essential for understanding the toxicity, mobilization, and fate of...     

Dissolved organic phosphorus and sulphur as influenced by sorptive interactions with mineral subsoil horizons

This study tested the hypothesis that, like dissolved organic nitrogen (N), dissolved organic phosphorus (P) and sulphur (S) are more mobile in soil than is organic carbon (C). To do so, I compared the sorption of organic P and S to subsoil materials with that of organic C. Soil samples were equilibrated with water‐soluble organic matter from the forest floor at pH 4 and in the equilibrium solutions organic C, P, and S, and their distributions between the hydrophilic and hydrophobic fraction were determined. Sorption of C within the organic matter did not differ from that of P and S. However, the hydrophilic fraction contained the vast majority of P and S and sorbed far less than the hydrophobic fraction. So the overall retention of organic P and S was smaller than that of organic C. This result suggested that dissolved organic matter is more important in the loss of plant nutrients than in the release of C from soil.     

Changes in the concentrations and speciation of aluminum in response to an experimental addition of ammonium sulfate to the bear Brook Watershed,Maine, USA

An understanding of the biogeochemistry of aluminum (Al) in acid-sensitive terrestrial and aquatic ecosystems is critical to assessments of the effects of acidic deposition. Bear Brook Watershed, Maine, USA includes paired watersheds, East Bear and West Bear. Starting in November 1989, experimental additions of ammonium sulfate ((NH₄)₂SO₄; 900 mol/ha-yr) have been made to West Bear Brook Watershed. Chemical analysis of soil and stream waters were conducted to evaluate the speciation of Al prior to (1987–89) and following (1989–92) the experimental treatments. Before the treatments, soilwater Al occurred largely as inorganic monomeric Al (Ali). Concentrations of organic monomeric Al (Alo), Ali and dissolved organic C (DOC) were high in soil solutions draining the E horizon, and decreased in the lower mineral soilwater (Bs horizon) and streamwater. Streamwater concentrations of monomeric Al (Alm) were largely in the form of Alo. After the (NH₄)₂SO₄ treatments were initiated in the West Bear Brook Watershed, concentrations of Alm increased in soilwater and streamwater, largely as Ali. These increases in Al accompanied decreases in pH and increases in concentrations of SO₄ ^2? and NO₃ ^? in drainage waters. Increases in stream concentrations of Al were particularly evident during high flow events. This pattern, coupled with the increases in concentrations of Ali in upper soilwaters in response to the (NH₄)₂SO₄ addition, suggests that episodic increases in Ali were due to inputs of water entering the stream from shallow hydrologic flowpaths.     

Bottom sediments in a humic lake with artificially increased calcium content: sink or source for phosphorus?

Lake Flosek (north-eastern part of Poland) is a small shallow and without outflow lake which has been limed in 1970. The concentration of Ca was increased from 3-4 mg L-1 to 17 mg L-1 in the water and from 0.2-0.3% dry weight to 0.9-1.7% dry weight in sediments (5 cm upper layer) due to CaCO3 addition to the lake. In the spring-summer seasons of 1992 and 1993, an experimental study was conducted in Lake Flosek to assess the capacity of bottom sediments to uptake and release mineral phosphorus. The rate of phosphorus exchange between sediments and near-bottom water was experimentally measured under conditions of high (100%), and of reduced (10%) oxygen saturation in near-bottom water. To determine the component of sediments responsible for the uptake of most phosphorus, the proportions of phosphorus forms in sediments were analysed. Sediments of Lake Flosek showed a slight tendency to release phosphates. The rate of this process was similar under high (100%) and low (10%) oxygen saturations ranging from - 0.161 to + 0.200 mg P m-2 d-1. This is much lower (by 1-2 orders of magnitude) than reported from other harmonic, non-humic lakes. In the total phosphorus pool, the highest content of phosphorus was found in the organic and residual phosphorus fractions (over 70% of the total phosphorus in sediments). The largest part of the readily extractable phosphorus was found in the fraction bound to Al and humic substances (41%). Both these fractions determine a weak exchange of phosphorus between sediments and water. No difference in P-release related to P-fraction compound was found in the cores taken from three sites in the lake.     

Phosphorus Fractionation and Short-term Mobility in the Surface Sediment of a Polymictic Shallow Lake Treated with a Low Dose of Alum (Courtille Lake,France)

Lake Courtille was a polymictic eutrophic lake prone to large pH variations and sediment resuspension. Short term P release (96 hr) under laboratory resuspension conditions for two sedimentsample types, surface sediments which represent sediment accumulated over several years and trap sediments which representcurrent year sediment, was studied. The experiments were carriedout in oxic conditions at different pH values. According to phosphorus fractionation, Fe-bound-P, Al-bound-P and Organic-bound-P comprised the largest phosphorus pool (80% of Total Phosphorus). Phosphorus release was from the Fe-P, Al-P and organic fractions. These represent 35% of the total phosphorus content at pH 10. At circumneutral pH, in oxic conditions, a lower quantity of P was released (roughly 4% of total P sediment content) than at pH 10. The organic matter mineralization occurring at the end of summer can also influenceP release as illustrated by the difference in total phosphoruscontent between sediment samples of 2000 and of the last five years. This type of P release was observed in Lake Courtille. High soluble reactive phosphorus content was measured in the water column at the end of summer. Aluminium treatment was thus not efficient in preventing P release. Moreover, a higher alum dose was needed to reduce P content in the water column in order to decrease primary productivity and subsequent organic matter sedimentation.     

天鹅湖沉积物对磷的吸附动力学及等温吸附特征

以荣成天鹅湖这一天然泻湖为研究对象,研究了6个样点沉积物对磷的吸附动力学曲线和等温吸附方程,并分析了沉积物理化性质与磷吸附参数间的关系.结果表明,天鹅湖不同区域沉积物对磷的吸附动力学均符合二级动力学方程,吸附反应主要在前10h内完成,且0～2h内反应迅速.根据Langmuir模型,6个样点沉积物对磷的理论吸附容量(Qmax)的范围为294.12～1 111.11 mg/kg,其中湖区北部和中部沉积物的吸附能力高于南部.沉积物对水体中磷的吸附解吸平衡浓度(EPC0)的变幅为0.002 ～ 0.033 mg/L,其与沉积物本底吸附态磷(NAP)呈较弱的正相关关系.本研究条件下,大部分样点的EPC0小于上覆水中磷的浓度,其中湖区西北部和东南部沉积物中磷具有向上覆水体释放的趋势.沉积物的NAP与总氮、有机质、活性铝和黏粒间均呈显著正相关,Qmax与铁铝结合态磷、有机质、活性铝和粉粒间呈显著的正相关关系.活性铝、有机质和粒度是影响沉积物磷吸附的主要因素.