University of Maine

To test the hypothesis that lecturing maximizes learning and course performance, we metaanalyzed 225 studies that reported data on examination scores or failure rates when comparing student performance in undergraduate science, technology, engineering, and mathematics (STEM) courses under traditional lecturing versus active learning. The effect sizes indicate that on average, student performance on examinations and concept inventories increased by 0.47 SDs under active learning (n = 158 studies), and that the odds ratio for failing was 1.95 under traditional lecturing (n = 67 studies). These results indicate that average examination scores improved by about 6% in active learning sections, and that students in classes with traditional lecturing were 1.5 times more likely to fail than were students in classes with active learning. Heterogeneity analyses indicated that both results hold across the STEM disciplines, that active learning increases scores on concept inventories more than on course examinations, and that active learning appears effective across all class sizes--although the greatest effects are in small (n ≤ 50) classes. Trim and fill analyses and fail-safe n calculations suggest that the results are not due to publication bias. The results also appear robust to variation in the methodological rigor of the included studies, based on the quality of controls over student quality and instructor identity. This is the largest and most comprehensive metaanalysis of undergraduate STEM education published to date. The results raise questions about the continued use of traditional lecturing as a control in research studies, and support active learning as the preferred, empirically validated teaching practice in regular classrooms.

Ecological extinction caused by overfishing precedes all other pervasive human disturbance to coastal ecosystems, including pollution, degradation of water quality, and anthropogenic climate change. Historical abundances of large consumer species were fantastically large in comparison with recent observations. Paleoecological, archaeological, and historical data show that time lags of decades to centuries occurred between the onset of overfishing and consequent changes in ecological communities, because unfished species of similar trophic level assumed the ecological roles of overfished species until they too were overfished or died of epidemic diseases related to overcrowding. Retrospective data not only help to clarify underlying causes and rates of ecological change, but they also demonstrate achievable goals for restoration and management of coastal ecosystems that could not even be contemplated based on the limited perspective of recent observations alone.

Atmospheric carbon dioxide concentration is expected to exceed 500 parts per million and global temperatures to rise by at least 2 degrees C by 2050 to 2100, values that significantly exceed those of at least the past 420,000 years during which most extant marine organisms evolved. Under conditions expected in the 21st century, global warming and ocean acidification will compromise carbonate accretion, with corals becoming increasingly rare on reef systems. The result will be less diverse reef communities and carbonate reef structures that fail to be maintained. Climate change also exacerbates local stresses from declining water quality and overexploitation of key species, driving reefs increasingly toward the tipping point for functional collapse. This review presents future scenarios for coral reefs that predict increasingly serious consequences for reef-associated fisheries, tourism, coastal protection, and people. As the International Year of the Reef 2008 begins, scaled-up management intervention and decisive action on global emissions are required if the loss of coral-dominated ecosystems is to be avoided.

Our growing awareness of the microbial world's importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth's microbial diversity.

Although the dramatic climate disruptions of the last glacial period have received considerable attention, relatively little has been directed toward climate variability in the Holocene (11,500 cal yr B.P. to the present). Examination of ?50 globally distributed paleoclimate records reveals as many as six periods of significant rapid climate change during the time periods 9000"8000, 6000"5000, 4200"3800, 3500"2500, 1200"1000, and 600"150 cal yr B.P. Most of the climate change events in these globally distributed records are characterized by polar cooling, tropical aridity, and major atmospheric circulation changes, although in the most recent interval (600"150 cal yr B.P.), polar cooling was accompanied by increased moisture in some parts of the tropics. Several intervals coincide with major disruptions of civilization, illustrating the human significance of Holocene climate variability.

▪ Abstract Nonindigenous species can bring about a form of extinction of native flora and fauna by hybridization and introgression either through purposeful introduction by humans or through habitat modification, bringing previously isolated species into contact. These phenomena can be especially problematic for rare species coming into contact with more abundant ones. Increased use of molecular techniques focuses attention on the extent of this underappreciated problem that is not always apparent from morphological observations alone. Some degree of gene flow is a normal, evolutionarily constructive process, and all constellations of genes and genotypes cannot be preserved. However, hybridization with or without introgression may, nevertheless, threaten a rare species' existence.

Continued growth and intensification of aquaculture production depends upon the development of sustainable protein sources to replace fish meal in aquafeeds. This document reviews various plant feedstuffs, which currently are or potentially may be incorporated into aquafeeds to support the sustainable production of various fish species in aquaculture. The plant feedstuffs considered include oilseeds, legumes and cereal grains, which traditionally have been used as protein or energy concentrates as well as novel products developed through various processing technologies. The nutritional composition of these various feedstuffs are considered along with the presence of any bioactive compounds that may positively or negatively affect the target organism. Lipid composition of these feedstuffs is not specifically considered although it is recognized that incorporating lipid supplements in aquafeeds to achieve proper fatty acid profiles to meet the metabolic requirements of fish and maximize human health benefits are important aspects. Specific strategies and techniques to optimize the nutritional composition of plant feedstuffs and limit potentially adverse effects of bioactive compounds are also described. Such information will provide a foundation for developing strategic research plans for increasing the use of plant feedstuffs in aquaculture to reduce dependence of animal feedstuffs and thereby enhance the sustainability of aquaculture.

Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.

Kelp forests are phyletically diverse, structurally complex and highly productive components of coldwater rocky marine coastlines. This paper reviews the conditions in which kelp forests develop globally and where, why and at what rate they become deforested. The ecology and long archaeological history of kelp forests are examined through case studies from southern California, the Aleutian Islands and the western North Atlantic, well-studied locations that represent the widest possible range in kelp forest biodiversity. Global distribution of kelp forests is physiologically constrained by light at high latitudes and by nutrients, warm temperatures and other macrophytes at low latitudes. Within mid-latitude belts (roughly 40–60° latitude in both hemispheres) well-developed kelp forests are most threatened by herbivory, usually from sea urchins. Overfishing and extirpation of highly valued vertebrate apex predators often triggered herbivore population increases, leading to widespread kelp deforestation. Such deforestations have the most profound and lasting impacts on species-depauperate systems, such as those in Alaska and the western North Atlantic. Globally urchin-induced deforestation has been increasing over the past 2–3 decades. Continued fishing down of coastal food webs has resulted in shifting harvesting targets from apex predators to their invertebrate prey, including kelp-grazing herbivores. The recent global expansion of sea urchin harvesting has led to the widespread extirpation of this herbivore, and kelp forests have returned in some locations but, for the first time, these forests are devoid of vertebrate apex predators. In the western North Atlantic, large predatory crabs have recently filled this void and they have become the new apex predator in this system. Similar shifts from fish- to crab-dominance may have occurred in coastal zones of the United Kingdom and Japan, where large predatory finfish were extirpated long ago. Three North American case studies of kelp forests were examined to determine their long history with humans and project the status of future kelp forests to the year 2025. Fishing impacts on kelp forest systems have been both profound and much longer in duration than previously thought. Archaeological data suggest that coastal peoples exploited kelp forest organisms for thousands of years, occasionally resulting in localized losses of apex predators, outbreaks of sea urchin populations and probably small-scale deforestation. Over the past two centuries, commercial exploitation for export led to the extirpation of sea urchin predators, such as the sea otter in the North Pacific and predatory fishes like the cod in the North Atlantic. The large-scale removal of predators for export markets increased sea urchin abundances and promoted the decline of kelp forests over vast areas. Despite southern California having one of the longest known associations with coastal kelp forests, widespread deforestation is rare. It is possible that functional redundancies among predators and herbivores make this most diverse system most stable. Such biodiverse kelp forests may also resist invasion from non-native species. In the species-depauperate western North Atlantic, introduced algal competitors carpet the benthos and threaten future kelp dominance. There, other non-native herbivores and predators have become established and dominant components of this system. Climate changes have had measurable impacts on kelp forest ecosystems and efforts to control the emission of greenhouse gasses should be a global priority. However, overfishing appears to be the greatest manageable threat to kelp forest ecosystems over the 2025 time horizon. Management should focus on minimizing fishing impacts and restoring populations of functionally important species in these systems.

BACKGROUND: The National Birth Defects Prevention Network collects state-specific birth defects surveillance data for annual publication of prevalence estimates and collaborative research projects. In 2006, data for 21 birth defects from 1999 through 2001 were presented as national birth prevalence estimates. The purpose of this report was to update these estimates using data from 2004 through 2006. METHODS: Population-based data from 11 active case-finding programs, 6 passive case-finding programs with case confirmation, and 7 passive programs without case confirmation were used in this analysis. Pooled birth prevalence estimates for 21 birth defects, stratified by case ascertainment approach, were calculated. National prevalence estimates, adjusted for maternal race/ethnicity and maternal age (trisomy 13, trisomy 18, and Down syndrome only) were determined using data from 14 programs. The impact of pregnancy outcomes on prevalence estimates was also assessed for five specific defects. RESULTS: National birth defects prevalence estimates ranged from 0.72 per 10,000 live births for common truncus to 14.47 per 10,000 live births for Down syndrome. Stratification by type of surveillance system showed that active programs had a higher prevalence of anencephaly, anophthalmia/microphthalmia, cleft lip with or without cleft palate, reduction defect of upper limbs, and trisomy 18. The birth prevalence of anencephaly, trisomy 13, and trisomy 18 also varied substantially with inclusion of elective terminations. CONCLUSION: Accurate and timely national estimates of the prevalence of birth defects are needed for monitoring trends, assessing prevention efforts, determining service planning, and understanding the burden of disease due to birth defects in the United States.

John Aber, William McDowell, Knute Nadelhoffer, Alison Magill, Glenn Berntson, Mark Kamakea, Steven McNulty, William Currie, Lindsey Rustad, Ivan Fernandez

Practical needs in geographic information systems (GIS) have led to the investigation of formal and sound methods of describing spatial relations. After an introduction to the basic ideas and notions of topology, a novel theory of topological spatial relations between sets is developed in which the relations are defined in terms of the intersections of the boundaries and interiors of two sets. By considering empty and non-empty as the values of the intersections, a total of sixteen topological spatial relations is described, each of which can be realized in R 2. This set is reduced to nine relations if the sets are restricted to spatial regions, a fairly broad class of subsets of a connected topological space with an application to GIS. It is shown that these relations correspond to some of the standard set theoretical and topological spatial relations between sets such as equality, disjointness and containment in the interior.

The use of fluorescence spectrometry has been suggested as a simple method to determine the extent of natural organic matter humification by quantifying the red-shifting of fluorescence emission that occurs with increasing humification. Humification indices are calculated by dividing fluorescence intensity at longer wavelengths by intensity at shorter wavelengths. These indices calculated without any specific efforts to standardize dissolved organic matter (DOM) concentration will result in index values thatvary with DOM concentration due to fluorescence innerfiltering effects. This study critically evaluated the effect of DOM concentration on humification index determination using organic matter isolated from field corn extract, soil: water extract, and soil fulvic acid. The results show that humification index values are sensitive to DOM concentration of the solution and are linear with respect to transmittance of the solution at the 254 nm used as the excitation wavelength. An approximate correction for DOM is to exploit the linear nature of the regression fit and to determine index values at the extrapolated 100% transmittance value. An exact correction using explicit correction factors for both primary and secondary innerfiltration effects was shown to give humification index values that are concentration invariant when absorbance of the solution at 254 nm was less than approximately 0.3 unit. Defining the humification index as the fluorescence intensity in the 300-345 nm region divided by the sum of intensity in the 300-345 nm and 435-480 nm regions was statistically advantageous. This study suggests that for quantitative results which can be used to compare humification of natural organic matter across different studies, correction of the fluorescence emission spectra for innerfiltration effects is needed.

Global demand for macroalgal and microalgal foods is growing, and algae are increasingly being consumed for functional benefits beyond the traditional considerations of nutrition and health. There is substantial evidence for the health benefits of algal-derived food products, but there remain considerable challenges in quantifying these benefits, as well as possible adverse effects. First, there is a limited understanding of nutritional composition across algal species, geographical regions, and seasons, all of which can substantially affect their dietary value. The second issue is quantifying which fractions of algal foods are bioavailable to humans, and which factors influence how food constituents are released, ranging from food preparation through genetic differentiation in the gut microbiome. Third is understanding how algal nutritional and functional constituents interact in human metabolism. Superimposed considerations are the effects of harvesting, storage, and food processing techniques that can dramatically influence the potential nutritive value of algal-derived foods. We highlight this rapidly advancing area of algal science with a particular focus on the key research required to assess better the health benefits of an alga or algal product. There are rich opportunities for phycologists in this emerging field, requiring exciting new experimental and collaborative approaches.

The extent to which biodiversity change in local assemblages contributes to global biodiversity loss is poorly understood. We analyzed 100 time series from biomes across Earth to ask how diversity within assemblages is changing through time. We quantified patterns of temporal α diversity, measured as change in local diversity, and temporal β diversity, measured as change in community composition. Contrary to our expectations, we did not detect systematic loss of α diversity. However, community composition changed systematically through time, in excess of predictions from null models. Heterogeneous rates of environmental change, species range shifts associated with climate change, and biotic homogenization may explain the different patterns of temporal α and β diversity. Monitoring and understanding change in species composition should be a conservation priority.

Nuclear-magnetic-resonance measurements of the proton-spin relaxation for water in biological cells are known to exhibit a multiexponential decay. A theory, based on the diffusion equation using the bulk diffusivity of water, is developed to explain this phenomenon. It is shown that multiexponential decay arises simply as a consequence of an eigenvalue problem associated with the size and shape of the cell and that this multiexponential decay can only be observed for samples whose size is of the order of a biological cell. As an example, the theory is applied to a previously published data for rat gastronemius cells. Excellent agreement is obtained, and furthermore, the size of the cell is calculated by fitting the theory to the experiment.

An introduction to wind tunnel design, wind tunnel data uncertainty analysis, and nondimensional presentation of measured data is presented. The primary components of a wind tunnel and the purposes of each are discussed. The importance of delivering uniform flow to the test section cross section is considered with regard to the effect of nonuniform flow on the measured thermal performance of a device, which is shown to be velocity-dependent. A simple methodology for constructing a wind tunnel with high-quality test section flow is described. The RMS (root-mean square) approach to uncertainty analysis is covered for several wind-tunnel-measured parameters. The significance of presenting measured results in a nondimensional coordinate system is illustrated by the discussion of a water tunnel experiment. The discussion is extended to the presentation of a hypothetical set of natural convection measurements and a nondimensional coordinate frame for this experiment is suggested.>

Lebel, L., J. M. Anderies, B. Campbell, C. Folke, S. Hatfield-Dodds, T. P. Hughes. and J. Wilson. 2006. Governance and the capacity to manage resilience in regional social-ecological systems. Ecology and Society 11(1): 19. https://doi.org/10.5751/ES-01606-110119

Ocean biogeochemical and ecosystem processes are linked by net primary production (NPP) in the ocean's surface layer, where inorganic carbon is fixed by photosynthetic processes. Determinations of NPP are necessarily a function of phytoplankton biomass and its physiological status, but the estimation of these two terms from space has remained an elusive target. Here we present new satellite ocean color observations of phytoplankton carbon (C) and chlorophyll (Chl) biomass and show that derived Chl:C ratios closely follow anticipated physiological dependencies on light, nutrients, and temperature. With this new information, global estimates of phytoplankton growth rates (μ) and carbon‐based NPP are made for the first time. Compared to an earlier chlorophyll‐based approach, our carbon‐based values are considerably higher in tropical oceans, show greater seasonality at middle and high latitudes, and illustrate important differences in the formation and demise of regional algal blooms. This fusion of emerging concepts from the phycological and remote sensing disciplines has the potential to fundamentally change how we model and observe carbon cycling in the global oceans.

Acidic deposition is the transfer of strong acids and acid-forming substances from the atmosphere to the surface of the Earth. The composition of acidic deposition includes ions, gases, and particles derived from the following: gaseous emissions of sulfur dioxide (SO2), nitrogen oxides (NOx), ammonia (NH3), and particulate emissions of acidifying and neutralizing compounds. Over the past quarter century of study, acidic deposition has emerged as a critical environmental stress that affects forested landscapes and aquatic ecosystems in North America, Europe, and Asia. This complex problem is an example of a new class of environmental issues that are multiregional in scale and are not amenable to simple resolution by policymakers. Acidic deposition can originate from transboundary air pollution and can affect large geographic areas. It is highly variable across space and time, links air pollution to diverse terrestrial and aquatic ecosystems, and alters the interactions of many elements (e.g., sulfur [S], nitrogen [N], hydrogen ion [H+], calcium [Ca2+], magnesium [Mg2+], and aluminum [Al]). It also contributes directly and indirectly to biological stress and to the degradation of ecosystems. Despite the complexity of the effects of acidic deposition, North American and European management actions directed toward the recovery of damaged natural resources have resulted in recent decreases in both emissions and deposition of acidic S compounds. Accordingly, acidic deposition presents an instructive case study for coordinating science and policy efforts aimed at resolving large-scale environmental problems. Acidic deposition was first identified by R. A. Smith in England in the 19th century (Smith 1872). Acidic deposition emerged as an ecological issue in the late 1960s and early 1970s with reports of acidic precipitation and surface water acidification both within Sweden and around Scandinavia (Oden 1968). The first report of acidic precipitation in North America was made at the Hubbard Brook Experimental Forest (HBEF) in the remote White Mountains of New Hampshire, based on collections begun in the early 1960s (Likens et al. 1972). Controls on SO2 emissions in the United States were first implemented after passage of the 1970 amendments to the Clean Air Act (CAAA). In 1990, Congress passed Title IV of the Acid Deposition Control Program of the CAAA to further decrease emissions of SO2 and to initiate controls on NOx from electric utilities, which contribute to acidic deposition. The Acid Deposition Control Program had two goals: (1) By 2010, a 50% decrement from 1980 levels of SO2 utility emissions (amounting to 9.1 million metric tons per year, or 10 million short tons); (2) also by 2010, an NOx emission rate limitation (0.65 lbs NOx/m BTU in 1990 to 0.39 lbs NOx/m BTU in 1996), which will achieve a reduction of 1.8 million metric tons per year (2 million short tons) as NO2) in NOx utility emissions from the amount that would have occurred without emission rate controls. Both SO2 and NOx provisions focus on large utilities. The legislation capped total utility emissions of SO2 at 8.12 million metric tons per year (8.95 million short tons), whereas nonutility emissions of SO2 were capped at 5.08 million metric tons per year (5.6 million short tons). Because the legislation did not specify caps for NOx emissions, emissions may increase over time as the demand for electricity increases. The beginning of the 2lst century offers the opportunity to assess the effects of three decades of clean air legislation on emissions reductions; on air pollution levels, trends, and chemical effects of acidic deposition; and on ecosystem recovery. The opportunity also exists to look ahead to the anticipated reauthorization of the Clean Air Act and to the next national assessment of acidic deposition, scheduled for mid-2001. In this article we examine the ecological effects of acidic deposition in the study region of New England and New and we the emissions and ecosystem by on three critical This on in the United with from the and United States and from on from a that the of precipitation and (Likens and Because the is in a region with that is to chemical and acidic surface are of of the that are to acidic deposition. we from the at with from the of in the which had the and Program of the had of the of et al. In had of and had to of and of the have of the of of and of in the water at of from and is critical for and for complex environmental problems. 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The and and et al. is a and that of by and water was with a that (e.g., and in a is to in and aquatic ecosystems et al. et al. The have at to the effects of (e.g., and air on and aquatic resources and et al. et al. emissions and deposition (e.g., of past emissions we of deposition of S and at In we to the in and in the of and water to this deposition with of the of to is in et al. that total deposition of S at from in to a recent of in and the total deposition has that also that past was was 10 was was and was 50% of which was in an with at that has to in to acidic deposition and to of by acidic deposition has to a increase in a decrease in from to a decrease in to and in as the 10 in the of and water at is the that strong with of after in the resulted in the acidification of water the has a in of This decrease in to both decreases in emissions of SO2 and to precipitation of (Likens et al. In has a decrease in of that is not with a in emissions of NOx or in deposition of in of strong have resulted in in The increase in has of decreases in the of is both within the and the of New and across New of from the which was in the early in surface water and in the of strong in the and as as in the New England et al. that the rate of in for and surface was the for New England In to the at in of in New England in increase in was in the and This is to the decrease in the of in the and with the New England that the of recovery of and surface to New England surface is to the of acidic deposition in New in of New England This has resulted in of in in New et al. has effects on the of surface in and contribute to in and in the of and et al. and of both as and are directly to and is in is in the and controls and the of and surface with and as as of are to directly the stress by and of also contributes to with are to as by the by the and the by the at was in whereas were in The in the region had and as as of to with and in the region are to at and have for or or may to with also had with is to an in the of from have that of in a water is with and and et al. in in decreases in by et al. the of by the et al. are from with as and et al. that as for the by the and also the of acidic as by in with and and exists acidic which from deposition of strong and In acidic of water after precipitation or an opportunity to the effects of on that as are by acidic water in the region et al. et al. acidification is in and with ecosystems large in water and for et al. that acidification can have effects on in of and The study that with to had et al. The of was the chemical variable to in the and Because of with in and were of in for The with had and and the and In that whereas in did In was in with and with a of were from with and with a of we emissions and deposition to in the and ecosystems to electric in the United States have or the SO2 emissions reduction by the Acid Deposition Control Program of the 1990 CAAA et al. reports that this emissions will not ecosystems et al. et al. has Congress to that for in utility emissions of SO2 and acidic deposition as a national environmental to emissions are and to further will recovery from acidic deposition. we a for ecosystem recovery from acidic deposition, of chemical that for emissions by utilities, and the to in deposition that emissions would and to ecosystems at the Acidic deposition and aquatic ecosystems by to chemical S deposition to the United States has over the past and ecosystems have to of strong acids for many the 1970 have decreases in S deposition; as a aquatic ecosystems in the have chemical recovery et al. critical chemical to with the of effects to a of water that is and a that is that is at with to acidification from acidic deposition and 1990, and surface water that is or of that aquatic are at from surface water acidification of acidic deposition and can also as of chemical recovery (e.g., water surface water and of is for ecosystem and and of acidification recovery is at the ecosystem we that the will two decreases in acidic deposition emissions controls will a of chemical recovery in and aquatic ecosystems. time for the first will across ecosystems and will a of the following: the of decreases in deposition the of of the rate of and of the and rate to which of S and are as or as to et al. In acidic with we that in of strong will in in the of surface (Likens et al. et al. and in the as the will recovery of may in in which deposition has of S and that will or of In that chemical recovery will with controls on recovery can at (e.g., and of by (e.g., et al. The in ecosystem recovery is biological which can chemical recovery is to and of and The time for biological recovery is the and time for recovery of terrestrial ecosystems after decreases in acidic deposition, is to at decades after is of the of and the complex interactions of and that of may in to chemical whereas of are to 10 and may in to 10 after the recovery of of by is that aquatic ecosystems to the that in the chemical is to recovery of the ecosystem that and The rate and of ecosystem recovery is to the and of emissions SO2 and NOx emissions with the 1990 CAAA and with aimed at utility emissions which were in the of this to to a of acidic deposition and ecosystem effects at the The for in utility emissions of SO2 and the emissions for of the as by the and we levels of on for emission levels after of the 1990 CAAA the would utility SO2 emissions by and would decrease utility NOx emissions of the Acid Deposition Control Program of the 1990 and and would CAAA whereas would emissions of the we the is a of for utility emissions of SO2 and includes NOx from to to achieve a of the the and that to to the and the of which is to the and the of The of the the to with a of or to electric utility and a of or from the as to the we ecosystem at the to a of emissions for three S deposition without of the 1990 CAAA S deposition after of the 1990 CAAA S deposition after the 1990 with and in utility SO2 emissions in The and the of emissions in the would amount to and of the total emissions of that decreases in SO2 emissions will in and total S deposition in by et al. this SO2 emissions and deposition. Because the SO2 emissions have a on S deposition in the we on S controls. did not decreases in or deposition. Controls on emissions also the effects of acidic deposition. in surface deposition in the region within the the of with of will increase from to Because contribute of total NOx emissions is that in utility NOx emissions will to the or of ecosystems in the not deposition that from or NOx emissions, which are both of to the that in S deposition will in and surface water at the The that the Acid Deposition Control Program will in in water at the for the will decrease by will increase by and will increase controls on SO2 emissions, as in in and water The for that a reduction in utility emissions of SO2 from levels anticipated the 1990 CAAA would a decrease in S deposition in 2010, which would decrease by by In a decrease in S deposition decrease in utility SO2 would decrease by by Despite in S deposition over the past (Likens et al. water at the Because of the of of from S deposition the past the recovery of water after decreases in strong has were controls the 1990 CAAA the rate of increase by the for is of and in S deposition in increase the rate of to and The reduction in S deposition in would in in a decrease in S deposition, would by the that a reduction in S deposition of the 1990 CAAA would in over and in of at by the chemical and biological recovery not by with of the for utility that the the reduction in S deposition at the the the and rate of chemical recovery. for controls on S emissions will in chemical and biological recovery and in in the of a not for the that of the total and of the are acidic of the that recovery of surface would the for the that that and and will in North America and are in the of a large-scale and acids have and or terrestrial and aquatic It is critical to and to the recovery of complex ecosystems in to decreases in acidic deposition. the and are in to anticipated in air and in deposition. to in water are and to and are is an to assess the of resources to decreases in It would to assess the recovery of aquatic directly to in surface water and from the and across the United States to