Comparative Limnology of High-Elevation Lakes and Reservoirs and Their Downstream Effects

Cohen, Adam Patrick University of California, Santa Barbara ProQuest D 2019 해외박사(DDOD)

Reservoirs are abundant worldwide, and have profound effects on downstream flow, water chemistry, and downstream biotic communities. However, studies focused on reservoir effects rarely contrast them with lakes, which provide a comparison of natural climatic conditions without the influence of reservoir management. I compared five high-elevation lakes and five reservoirs in the Sierra Nevada, over three years which encompassed a wide range of snowpacks and flow regimes. I sampled lake, reservoir, and outlet stream water chemistry year-round across the three years to quantify seasonal effects of reservoir management. In addition to outlet water chemistry, I collected benthic macroinvertebrates from lake and reservoir outlets during the ice-free season in conjunction with discharge to determine the effects of reservoir management on downstream invertebrate communities. In 2017, I measured aquatic carbon dioxide and diffusive flux from lakes and reservoirs, beginning under ice and until the end of the ice free season, to determine potential sources of high-elevation aquatic CO2 supersaturation and characterize ice-free season CO2 temporal dynamics. Lake and reservoir nutrient concentrations did not differ in any season or year across the study period. Linear mixed models developed surface and bottom water nutrient concentrations showed that the primary controls were related to basin characteristics and snowpack, but reservoir management in the form of seasonal drawdown was a significant predictor of surface nitrate and both hypolimnetic ammonium and SRP, and indicated that reservoir water deep-release export diminished hypolimnetic nutrient accumulation. Reservoir mean annual discharge was elevated relative to lakes, which in summer and fall of 2016 and 2017 caused significantly higher export of nutrients from reservoirs. However, elevated ammonium export did not cause divergence of lake and reservoir invertebrate assemblages in those seasons, nor did they differ in any season. Other flow metrics, such as peak annual flow and the recession period, were similar between lake and reservoir outlets across years despite reservoir management. Instead, non-metric multidimensional scaling showed that invertebrate communities were related to elevated flow, but not related to low flow metrics such as baseflow and minimum flows, which were greater below reservoirs. Reservoir management altered flow regimes and nutrient flux, but interannual climactic variability was more important for determining invertebrate community structure. Carbon dioxide was supersaturated in lake and reservoir surface waters for most of the ice-free season of 2017 despite low rates of ecosystem metabolism. Diffusive flux highest for the first 40 days after ice-off, and did not differ significantly between lakes and reservoirs, but was low relative to other water bodies. Linear mixed modeling indicated that the summer CO2 concentrations were primarily related to the duration of ice cover, allowing CO2 to accumulate under ice, which indicates that annual snowpack is a major determinant of summer CO2 evasion.

Using a landscape limnology framework to examine spatial patterns and processes that influence lake nutrients and productivity at macroscales

Fergus, Carol Emiko Michigan State University ProQuest Dissertations & 2016 해외박사(DDOD)

Some of the most-pressing and severe environmental perturbations threatening freshwater ecosystems operate at broad spatial scales and are changing at rapid rates such as land use conversion and climate change. However, it is not known how freshwater systems will respond to these broad-scale changes because multi-scaled, geophysical factors promote variation in freshwaters across regional to continental scales and likely influence the effects of these threats on freshwaters. To address these uncertainties requires interdisciplinary perspectives and concepts to study freshwaters within a multi-scaled geophysical context, which the fields of landscape limnology and macrosystems ecology provide. My dissertation research uses these perspectives to examine fundamental questions about spatial variation in and the multi-scaled drivers of lake nutrients and productivity at macroscales. In chapter 1, I examined spatial variation in the empirical relationships of lake total phosphorus (TP) and water color on chlorophyll a in over 800 north temperate lakes using spatially-varying coefficient models to characterize the space-varying and scale-dependent relationships that influence lake primary production. I found spatial autocorrelation in these relationships but that the scale of dependence varied for TP compared to water color. In chapter 2, I measured lake, wetland, and stream abundance and connectivity at a subcontinental extent in the Midwest and Northeast U.S. to describe macroscale patterns of the freshwater landscape. I found that freshwater abundance and connectivity spatial patterns were distinct from one another, and these patterns were related to hydrogeomorphic, climate, and land use variables. In chapter 3, I related multi-scale geospatial features to predict lake total phosphorus, total nitrogen, and water color to evaluate the hypotheses that freshwater systems (i.e., wetlands, streams, and groundwater) and their connectivity influence lake nutrients and carbon concentrations and may promote cross-scale interactions. I found that freshwater systems were related to all three lake response variables, and freshwater systems may promote cross-scale interactions where features at one spatial scale interact with features from another spatial scale to affect lake water chemistry. The above work allows us to gain a better understanding of the spatial patterns of variation in freshwater systems as well as the underlying variables that may promote this variation across broad spatial extents. Identifying relationships at these macroscales is an important step so that we are better positioned to respond to regional and global change by aligning the spatial scales of how lakes are studied with the scales at which disturbances and management decisions are taking place.

Taxonomy and distribution of the freshwater micro-crustaceans and green algae of Puerto Rico, three contributions to American cladocerology, and a bibliography on West Indian limnology

Santos Flores, Carlos Jose The University of Wisconsin - Madison 2001 해외박사(DDOD)

The first comprehensive and illustrated account of the freshwater micro-crustaceans (cladocerans, large branchiopods, and calanoid and cyclopoid copepods) of the West Indies, with emphasis in those of Puerto Rico, is presented. A total of 144 cladocerans, 4 fairy-shrimps, 4 clam-shrimps, 1 tadpole-shrimp and some 63 copepods are known for the West Indies. The diversity and distribution of the previously-mentioned groups and of the Ostracoda in the West Indies is summarized. In the second part, I prepared an annotated and illustrated account of the freshwater green algae known from Puerto Rico (Chlorophyta), with emphasis on the Sphaeropleales and Zygnematales. In the third part, <italic> Dumontia oregonensis</italic>, a cladoceran representing a new family in the Order Anomopoda, is described from pools in Agate Desert, Oregon, USA. Keys and descriptions are provided for the species in the chydorid genera <italic> Alona</italic> (including <italic>Nicsmimovius</italic> and <italic>Karualona </italic>) and <italic>Camptocercus</italic> occurring in the coterminous USA and the West Indies. One species of Alona, two of <italic>Karualona</italic> and two of <italic>Camptocercus</italic> are described as new. In the last part, I presented the results of a study on the plankton richness and basic limnology of 21 Puerto Rican reservoirs conducted in the winters and summers of 1997–1999. A survey of the phytoplankton in five major wetlands in Puerto Rico was also included. Plankton richness in these reservoirs has more than tripled in the last 48 years. The increase in species richness is in part due to improvements in taxonomy of the planktonic species, but colonization over the last 50 years was considered a main factor. Plankton richness was poorly correlated with factors such as reservoir age, elevation, area and most chemical variables. Water turbidity, pH and alkalinity were significantly correlated with the watershed area, suggesting that human disturbance is an important factor to be considered in future studies. A bibliography on the limnology of the West Indies was included, which is classified by major islands or island-groups.

Limnological influence of dams placed in series along the Perak River, Malaysia

Hashim, Zarul Hazrin Mississippi State University 2013 해외박사(DDOD)

An 18-month study (July 2009 - December 2010) was conducted to determine the influence of four dams located in series along the Perak River, in Malaysia: Temengor, Bersia, Kenering and Chenderoh dams. The framework for investigation centered around the Serial Discontinuity Concept (SDC) and the Cascading Reservoir Continuum Concept (CRCC). In addition to reservoir, tailwater and riverine reach characteristics, the interacting influences of tributary streams and watersheds were addressed. Variables included <italic>in-situ</italic> environmental physical parameters, nutrients, seston concentration and transport, and fish assemblage characteristics. <italic>In-situ</italic> variables, water and seston samples, were recorded/collected monthly from all four reservoirs, their associated riverine sections, and their primary tributaries. Fish samples were collected by using experimental gill nets in reservoirs. Fish were enumerated taxonomically and total length and weight were measured for the bony-lipped barb, <italic>Osteochilus hasselti </italic> (Valenciennes, 1842). Hypotheses were tested using analyses of variance with permutations. Relationships were determined using correlation, and multivariate and regression analyses. The integrated influences of discontinuity and cascading on nutrient and seston transport dynamics and fish assemblages (except for relative condition and biomass of <italic>O. hasselti</italic>) were operative in dynamic juxtaposition along the river's continuum, and depended on distance between dams and presence and size of tributary streams. However, principal tributaries along the four serial dams in the Perak River appeared to have little spatial influence on their respective system's nutrient and seston dynamics due to dilution effects of mainstem discharges. Among all tributaries, only the Rui River depicted reversal of the serial discontinuity trend in its system. Even so, its influence on its system was limited. Effects of ecosystem fragmentation along the river's continuum on in-situ, nutrients and seston transport dynamics, and fish assemblages existed, but not necessarily in line with the SDC nor in line with the CRCC. The dynamics of <italic>in-situ</italic>, nutrient, seston and fish assemblage parameters were more associated with land use, reservoir surface area and dam discharge. Results from this study generated a hypothesis that submerged woody vegetation in the reservoirs may augment and compensate lost nutrients, thereby minimizing functional impacts of serially-arranged dams.

Landscape Limnology: Lake morphology and process at the continental scale

Winslow, Luke Adam The University of Wisconsin - Madison 2014 해외박사(DDOD)

Many challenges facing humanity operate at the continental and global scales, pushing researchers to address environmental questions at such spatial scales. For issues of global change and biogeochemical cycles in inland waters, building a large-scale understanding of the extent and processes of inland waters is an important to predict and address present and future challenges. In this work, I take the focus off any single lake and instead work at the lake population scale. This forced me to break new research ground, synthesize new datasets, and re-examine existing theories at a new scale. In Chapter 2, I synthesized and examined a new dataset of lakes in the U.S. and went beyond lake surface area. By improving our understanding of lake shoreline, I improved our understanding of how lakes are linked to their landscapes. In Chapter 3, I broke new ground by building a simple mathematical model of lake population morphology and process, giving researchers a simple and powerful tool for conceptualizing lake population morphology and process. In Chapter 4, I used a large-scale dataset and a fractal model of lakes to examine how different processes can result in different observed distributions of lakes. While theory points to a fractal world, we hypothesize that scale-dependent processes alter the underlying distributional form, altering the observed distribution of lakes. Lastly, with Chapter 5, I examined water temperature trends at a new scale and found that small lakes have a muted response to climate change than larger lakes.

Modern Limnological and Paleolimnological Applications of Diatoms in Minnesota Lakes

Burge, David Robert Lawless ProQuest Dissertations & Theses University of Minn 2021 해외박사(DDOD)

Vertical Distributions of Limnological Variables and Thermal Stratification in a Regulated River

정은송 부산대학교 대학원 2019 국내석사

Hydro-physical alterations in rivers, such as constructions of dams and weirs are being carried out worldwide. Constructing of eight weirs and dredging resulted in deepening of the Nakdong River (525 km) depth from 2 to 6-10 meters which may allow the river to be stratified. In this study, I identified vertical distributions of water quality by conducting field surveys in the autumn, spring and summer for 24 hours from November 2017 to August 2018, at two points in downstream of the river. Eight limnological variables were measured at intervals of one to three meters in depth across the entire water column. To evaluate the thermal stratification, vertical gradients of temperature and Relative Water Column Stability (RWCS) were calculated using the measured water temperature. The relationships of the RWCS and vertical distributions of water quality and the impacts of the environmental factors on RWCS were analyzed. The vertical gradients and RWCS of the river indicated thermal stratification showing diurnal changes in the summer. The vertical differences of dissolved oxygen and chlorophyll-a and nutrients concentrations were significantly correlated to the RWCS. The RWCS was affected by the weir discharge and flow rate of the upstream regions with time-delay. Development of thermal stratification occurred when the discharge was lower than 28.6 m3/s. Thus, it is necessary to establish management measure for thermal stratification through the monitoring the vertical water quality and controlling the weirs operation. Further investigation on the relationship between discharge, stratification and water deterioration is needed. 세계적으로 하천에서 댐 건설이나 준설과 같은 수문학적 및 물리적 변화가 이루어지고 있다. 낙동강(525 km)은 보와 준설작업으로 수심이 2 m에서 6 m 이상 깊어져 성층현상이 발생할 가능성이 있다. 본 연구에서는 성층 정도에 따른 수질의 수직분포를 파악하기 위해 2017년 11월부터 2018년 8월까지 낙동강 하류 두 지점에서 가을과 봄, 여름 3회의 현장조사가 3 시간 간격으로 24 시간 동안 수행되었으며, 총 8개의 이화학적 항목이 수심 1-3m 간격으로 측정되었다. 수체의 성층을 평가하기 위하여, 측정된 수온을 이용하여 수온의 수직구배의 기울기와 수체안정도를 계산하였다. 수체안정도와 수질항목의 수직적 분포의 관계 및 환경요인과 수체안정도의 관계가 분석되었다. 그 결과 여름에 두 지점의 수체는 성층화되었으며 일변화를 나타내었다. 여름철 수질의 수직적 차이와 일변화는 다른 계절에 비해 높게 나타났다. 용존산소와 클로로필 a 및 영양염 농도의 수직적 차이는 수체안정도와 매우 유의한 상관관계를 보였다. 상류보의 방류 및 강의 유량은 시간이 지연된 후 하류의 수체안정도를 감소시켰으며 방류량이 28.6m3/s 이하일 경우 성층이 형성되는 것으로 나타났다. 따라서 수질의 수직적 분포를 모니터링하고 보의 운영을 조절하는 등, 하천의 열적 성층을 관리하는 방안의 수립이 필요하다. 이를 위해 하천의 유량과 열적 성층 그리고 수질 악화 현상 간의 관계에 대한 연구가 필요하다.

External drivers of limnetic bacterial community composition and function

Jones, Stuart E The University of Wisconsin - Madison 2008 해외박사(DDOD)

Bacteria are key components of biogeochemical processes that occur in lakes, and therefore we seek to understand factors that determine their community composition and function. A large majority of efforts to describe bacterial community dynamics has focused on chemical and biological drivers that originate within the lake. In this dissertation I attempt to characterize three factors originating outside the lakeshore (extrinsic factors) that structure lake bacterial community composition. Extreme weather events can drive rapid change in the physical structure of the water column of a lake. I explored the influence of typhoons on the physical structure and microbial community dynamics of Yuan Yang Lake, Taiwan. Following typhoon-induced mixis, restratification of the water column occurred rapidly and drove surprisingly repeatable patterns of bacterial community succession. Long distance atmospheric transport of bacterial cells is often cited as an explanation for the apparent cosmopolitan distribution of bacterial taxa. Surprisingly, efforts to measure immigration in bacterial communities are rare. I captured atmospherically deposited cells over two summer seasons, and found little overlap of bacterial taxonomic composition of 16S rRNA gene sequence databases from lakes and the atmosphere. Transport of terrestrial organic carbon into lakes has become a key area of study within limnology over the last decade. As the primary users of dissolved organic carbon, bacteria can meet a large portion of their energy and nutrient demand using terrestrial-derived organic matter. I conducted a survey of bacterial 16S rRNA gene composition in fifteen lakes positioned along a color (absorbance at 440 nm) : chlorophyll a gradient. My survey supported the hypothesis that bacterial populations partition along a carbon substrate source gradient and suggests hypothetical carbon source-bacterial interactions that should be explored further. Stable isotope tracers have been extremely useful in estimating the relative contribution of terrestrial- and aquatic-derived carbon used in aquatic secondary production. However, methods for estimating carbon stable isotope ratios in bacterial biomass or biomarkers are still under development. I attempted to develop a method combining fluorescent activated cell sorting, spooling wire micro-combustion, and isotope ratio mass spectrometry for estimation of carbon stable isotope ratios in bacterial biomass.

Behavior and ecology of the Giant Otter (Pteronura brasiliensis) in oxbow lakes of the Manu Biosphere Reserve, Peru

Davenport, Lisa C The University of North Carolina at Chapel Hill 2008 해외공개박사

The Giant Otter (Pteronura brasiliensis) is an endangered otter of Amazonian lakes and rivers. It is the only otter of 13 extant species to breed cooperatively in family groups, with young of several years helping to raise younger siblings. I studied giant otters' behavior and ecology in 4 oxbow lakes (or "cochas") in the Manu Biosphere Reserve, Peru during 2003-2006. The objectives of this research were: (1) to investigate whether oxbow lakes return to random or predictable faunal communities after annual flooding; (2) to document seasonal and annual patterns in the diets of giant otters on two phytoplankton-dominated oxbow lakes; and (3) to document and characterize helping behavior in giant otters. I initially classified the four study lakes into 2 lake types, phytoplankton-dominated lakes and macrophyte-dominated lakes. I obtained data on their faunal communities, limnology, and otter diet through four seasons of 2003, and during the dry-seasons of 2004-2006. I show that lakes' bird communities and caiman populations, and to a lesser degree fish communities, respond predictably by lake identity and type. Lake communities also responded to seasonal changes in 2003 data, but generalization to other years is complicated by the destructive flood in January of that year. I studied giant otters' diet using visual observations, and demonstrated seasonal and annual changes not previously reported for the species. Giant otters shift to more intensive use of small cichlid prey found in edge habitats when with young cubs in the dry season. In studying the giant otters' behavior, I showed that hunting skills and helping activities generally increase with age. This observation is consistent with a pattern of "slow learning" suggested by the Skills Hypothesis of Heinsohn (1991). I observed considerable variation in dispersal age and helping contribution within families, particularly with respect to defensive behaviors against potential threats. Finally, the elderly matriarch in one family switched from being a provider of large prey to a beggar from other family members in 2007, apparently from the effects of old age. During 8 days of observation, her offspring assisted her through sharing prey and other types of assistance.

Evaluating lake phytoplanton response to human disturbance and climate change using satellite imagery

Novitski, Linda Nicole Michigan State University 2014 해외박사(DDOD)

Accurate and cost-effective assessment of water quality is necessary for proper management and restoration of inland water bodies susceptible to algal bloom conditions. Landsat and MODIS satellite images were used to create chlorophyll and Secchi depth predictive models for algal assessment of Great Lakes and other lakes of the United States. Boosted regression tree (BRT) models using satellite imagery are both easy to use and can have high predictive performance. BRT models inferred chlorophyll and Secchi depth more accurately than linear regression models for all study locations. Inferred chlorophyll of inner Saginaw Bay was subsequently used in ecological models to help understand the ecological drivers of algal blooms in this ecosystem. For small lakes (non-Great Lakes), the best national Landsat model for ln-transformed chlorophyll was the BRT model and had a cross-validation R 2 of 0.44 and a 0.76 ln-transformed mug/L RMSE. The best national Landsat model for Secchi depth was also a BRT model that had an adjusted R 2 of 0.52 and a 0.80 m RMSE. We assessed the applicability of the national chlorophyll model for ecological analysis by comparing the total phosphorus- chlorophyll relationship with chlorophyll determined from sampling or remote sensing, which showed the total phosphorus- chlorophyll relationship had an adjusted R2 = 0.58 and 1.02 ln-transformed microg/L RMSE with sampled chlorophyll versus an adjusted R2 = 0.56 and 1.04 ln-transformed mug/L RMSE with chlorophyll determined by the boosted regression tree remote sensing model. For Great Lakes models, the MODIS BRT model predicted chlorophyll most accurately of the three BRT models and compared well to other models in the literature. BRT models for Landsat ETM+ and TM more accurately predicted chlorophyll than the MSS model and all Landsat models had favorable results when compared to the literature. BRT chlorophyll predictive models are useful in helping to understand historical, long-term chlorophyll trends and to inform us of how climate change may alter ecosystems in the future. In inner Saginaw Bay, annual average and upper quartile Landsat-derived chlorophyll decreased from 7.44 to 6.62 and 8.38 to 7.38 mug/L between 1973-1982, and annual upper quartile of 8-day phosphorus loads increased from 5.29 to 6.79 kg between 1973-2012. Simple linear and multiple regression models and Wilcoxon rank test results for MODIS and Landsat-derived chlorophyll indicate that distance from the Saginaw River mouth influences chlorophyll concentration in Saginaw Bay; Landsat-derived surface water temperature and phosphorus loads to a lesser extent. Mixed-effect models for MODIS and Landsat-derived chlorophyll were related to chlorophyll better than simple linear or multiple regressions, with random effects of pixel and sample date contributing substantially to predictive power (NSE=0.35-70), though phosphorus loads, distance to Saginaw River mouth, and water were significant fixed effects in most models. Water quality changes in Saginaw Bay between 1972-2012 were influenced by phosphorus loading and distance to the Saginaw River's mouth. Landsat and MODIS imagery are complementary platforms because of the long history of Landsat operation and the finer spectral resolution and image frequency of MODIS. Remote sensing water quality assessment tools can be valuable for limnological study, ecological assessment, and water resource management.