Oceanic turbulence from a planktonic perspective

The potential influences of turbulence on planktonic processes such as nutrient uptake, grazing, predation, infection, and mating have been explored in hundreds of laboratory and theoretical studies. However, the turbulence levels used may not represent those experienced by oceanic plankton, bringing into question their relevance for understanding planktonic dynamics in the ocean. Here, we take a data-centric approach to understand the turbulence climate experienced by plankton in the ocean, analyzing over one million turbulence measurements acquired in the open ocean. Median dissipation rates in the upper 100 m were < 10−8 W kg−1, with 99% of the observations < 10−6 W kg−1. Below mixed layers, the median dissipation rate was ~ 10−10 W kg−1, with 99% of the observations < 10−7 W kg−1. Even in strongly mixing layers the median dissipation rates rarely reached 10−5 W kg−1, decreasing by orders of magnitude over 10 m or less in depth. Furthermore, episodes of intense turbulence were transient, transitioning to background levels within 10 min or less. We define three turbulence conditions in the ocean: weak (< 10−8 W kg−1), moderate (10−8–10−6 W kg−1), and strong (> 10−6 W kg−1). Even the strongest of these is much weaker than those used in most laboratory experiments. The most frequent turbulence levels found in this study are weak enough for most plankton—including small protists—to outswim them, and to allow chemical plumes and trails to persist for tens of minutes. Our analyses underscore the primary importance of planktonic behavior in driving individual interactions

Journey to the Center of the Gyre: The Fate of the Tohoku Tsunami Debris Field

The 9.0 magnitude Tohoku earthquake that struck off the coast of Japan on March 11, 2011, was the fourth largest earthquake in recorded history and the largest ever to hit a densely populated region (Bertero, 2011; Lekkas et al., 2011). The ensuing tsunami inundated an area of about 561 km2 (Geospatial Information Authority, 2011), washing away an estimated 24.9 million tonnes of debris, including wood, sediments, plastics, industrial chemicals, and structural components (Oh, 2011). Two weeks following the tsunami, the meltdown of the Fukushima Daiichi nuclear reactors released radioactive elements into the atmosphere and coastal waters. Atmospheric deposition was found to be an important source of radioactivity in surface waters and may have contaminated the debris field, although the extent of this contamination remains unknown (Buesseler et al., 2012; Honda et al., 2012).Here, we follow the debris field along its predicted path from its source in Japanese coastal waters through the Kuroshio-Oyashio Extension, the North Pacific Current, and the California Current. From there, it will loop back toward the Hawaiian Islands, ultimately accumulating in the North Pacific Gyre (International Pacific Research Center, 2011b; Figure 1). Relying on precedents from previous natural disasters and ongoing observations, we attempt to predict the impact of this debris field on marine and coastal ecosystems in each of these regions. We predict that the Tohoku debris field will create a rare perturbation for ecosystems interconnected across the North Pacific, exacerbating the accumulating human impacts on the world ocean

Toward A Second-Generation Theory of Fiscal Federalism

Drawing on a wide range of literature and ideas, a new “second-generation theory of fiscal federalism” is emerging that provides new insights into the structure and working of federal systems. After a restatement and review of the first-generation theory, this paper surveys this new body of work and offers some thoughts on the ways in which it is extending our understanding of fiscal federalism and on its implications for the design of fiscal institutions. Copyright Springer Science + Business Media, Inc. 2005fiscal federalism, fiscal competition, regional and local governments,

Meta-analysis of individual-patient data from EVAR-1, DREAM, OVER and ACE trials comparing outcomes of endovascular or open repair for abdominal aortic aneurysm over 5 years.

BACKGROUND: The erosion of the early mortality advantage of elective endovascular aneurysm repair (EVAR) compared with open repair of abdominal aortic aneurysm remains without a satisfactory explanation. METHODS: An individual-patient data meta-analysis of four multicentre randomized trials of EVAR versus open repair was conducted to a prespecified analysis plan, reporting on mortality, aneurysm-related mortality and reintervention. RESULTS: The analysis included 2783 patients, with 14 245 person-years of follow-up (median 5·5 years). Early (0-6 months after randomization) mortality was lower in the EVAR groups (46 of 1393 versus 73 of 1390 deaths; pooled hazard ratio 0·61, 95 per cent c.i. 0·42 to 0·89; P = 0·010), primarily because 30-day operative mortality was lower in the EVAR groups (16 deaths versus 40 for open repair; pooled odds ratio 0·40, 95 per cent c.i. 0·22 to 0·74). Later (within 3 years) the survival curves converged, remaining converged to 8 years. Beyond 3 years, aneurysm-related mortality was significantly higher in the EVAR groups (19 deaths versus 3 for open repair; pooled hazard ratio 5·16, 1·49 to 17·89; P = 0·010). Patients with moderate renal dysfunction or previous coronary artery disease had no early survival advantage under EVAR. Those with peripheral artery disease had lower mortality under open repair (39 deaths versus 62 for EVAR; P = 0·022) in the period from 6 months to 4 years after randomization. CONCLUSION: The early survival advantage in the EVAR group, and its subsequent erosion, were confirmed. Over 5 years, patients of marginal fitness had no early survival advantage from EVAR compared with open repair. Aneurysm-related mortality and patients with low ankle : brachial pressure index contributed to the erosion of the early survival advantage for the EVAR group. Trial registration numbers: EVAR-1, ISRCTN55703451; DREAM (Dutch Randomized Endovascular Aneurysm Management), NCT00421330; ACE (Anévrysme de l'aorte abdominale, Chirurgie versus Endoprothèse), NCT00224718; OVER (Open Versus Endovascular Repair Trial for Abdominal Aortic Aneurysms), NCT00094575