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There can be little doubt that mitochondria do not need much of an introduction. It is widely known that they are the “powerhouses” of the cell and that they produce all of the ATP (adenosine triphosphate) needed to sustain life. In addition, all eukaryotes (organisms with a cell nucleus) contain these important organelles—or so it was thought. Here lies an interesting paradox: Although it was generally believed that all eukaryotes did have mitochondria, it was also generally believed that the serial endosymbiosis theory was correct; the endosymbiosis theory required the existence of eukaryotes without mitochondria. This assumption was formalized with the now-disproven Archezoa hypothesis, which stated that several groups of “primitive” eukaryotes were of premitochondrial descent. This paradoxically defined group of amitochondriate eukaryotes has resulted in a spate of publications that have significantly changed the perception of the role of mitochondria in overall cellular metabolism and that have important ramifications for our understanding of the origin of eukaryotic life.
The ecological effects of elevated atmospheric nitrogen (N) deposition on high-elevation lakes of the western and northeastern United States include nutrient enrichment and acidification. The nutrient enrichment critical load for western lakes ranged from 1.0 to 3.0 kilograms (kg) of N per hectare (ha) per year, reflecting the nearly nonexistent watershed vegetation in complex, snowmelt-dominated terrain. The nutrient enrichment critical load for northeastern lakes ranged from 3.5 to 6.0 kg N per ha per year. The N acidification critical loads associated with episodic N pulses in waters with low values of acid neutralizing capacity were 4.0 kg N per ha per year (western) and 8.0 kg N per ha per year (northeastern). The empirical critical loads for N-caused acidification were difficult to determine because of a lack of observations in the West, and high sulfur deposition in the East. For both nutrient enrichment and acidification, the N critical load was a function of how atmospheric N deposition was determined.
Concentrations of organic acids in freshwaters have increased significantly during recent decades across large parts of Europe and North America. Different theories of the causes (e.g., recovery from acidification, climate change, land use) have different implications for defining the preindustrial levels for dissolved organic carbon (DOC), which are crucial for assessing acidification and other aspects of water quality. We demonstrate this by classifying the acidification status of 66 lakes with long-term observations, representative of about 12,700 acid-sensitive lakes in nemoral and boreal Sweden. Of these lakes, 47% are classified as significantly acidified (ΔpH ≥ 0.4), assuming preindustrial DOC levels were equal to those observed in 1990. But if, instead, the higher DOC levels observed in 2009 define preindustrial conditions, half as many lakes are acidified (24%). This emphasizes the need to establish reference levels for DOC and casts new light on the classic controversy about natural versus anthropogenic acidification.
Lucinda A. McDade, David R. Maddison, Robert Guralnick, Heather A. Piwowar, Mary Liz Jameson, Kristofer M. Helgen, Patrick S. Herendeen, Andrew Hill, Morgan L. Vis
Stimulated in large part by the advent of the Internet, research productivity in many academic disciplines has changed dramatically over the last two decades. However, the assessment system that governs professional success has not kept pace, creating a mismatch between modes of scholarly productivity and academic assessment criteria. In this article, we describe the problem and present ideas for solutions. We argue that adjusting assessment criteria to correspond to modern scholarly productivity is essential for the success of individual scientists and of our discipline as a whole. The authors and endorsers of this article commit to a number of actions that constitute steps toward ensuring that all forms of scholarly productivity are credited. The emphasis here is on systematic biology, but we are not alone in experiencing this mismatch between productivity and assessment. An additional goal in this article is to begin a conversation about the problem with colleagues in other subdisciplines of biology.
Citizen scientists can play a vital role in the first-tier screening of chemical contaminants in aquatic environments. For this to occur, the citizen scientists must be motivated and convinced to coalesce into functioning but loosely structured groups. Furthermore, the data they collect will have to be inexpensive to gather but also meaningful at fairly high levels of discrimination. Finally, the data from individual citizen scientists will have to be integrated into a large, professionally managed, and comprehensive database. We contend that all of the above criteria are already met, and in fact, other environment-related disciplines are already putting citizen scientists into action. Citizen scientists represent a collective workforce that can amass large data sets at minimal effort or cost, which can then be analyzed in an aggregate and used as a first-tier screening tool in environmental assessment.
Large-scale sell-offs of industrial timberlands in the United States have prompted public and private investments in a new class of “working forest” land deals, notable for their large size and complex divisions of property rights. These transactions have been pitched as “win-win-win” deals that provide social, economic, and ecological benefits. Despite hundreds of millions of dollars invested in these transactions, we found a paucity of evidence that their supposed benefits are being realized. Monitoring programs necessary to gather such evidence tend to be underfunded, short term, and focused on a limited set of indicators. The few projects with more comprehensive monitoring programs had long-term funding sources, formal mechanisms for incorporating data into subsequent management decisions, and combined multidisciplinary monitoring techniques. We propose that a relatively modest allocation of funds to monitoring could help assess—and hopefully improve—the effectiveness of current and future transactions, to see if the promise of “win-win-win” is actually delivered.
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