The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. 
The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The δ^(15)N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different δ^(15)N values. The variability of the relationship between the δ^(15)N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in ^(15)N relative to the diet, with the difference between the δ^(15)N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The δ^(15)N values of collagen and chitin, biochemical components that are often preserved in fossil animal remains, are also related to the δ^(15)N value of the diet. 
The dependence of the δ^(15)N values of whole animals and their tissues and biochemical components on the δ^(15)N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different δ^(15)N values. The nitrogen isotopic method of dietary analysis probably can be used to estimate the relative use of legumes vs non-legumes or of aquatic vs terrestrial organisms as food sources for extant and fossil animals. However, the method probably will not be applicable in those modern ecosystems in which the use of chemical fertilizers has influenced the distribution of nitrogen isotopes in food sources. 
The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the δ^(15)C and δ^(15)N values of bone collagen suggest that C_4 and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis.

Influence of Diet On the Distribtion of Nitrogen Isotopes in Animals

Dead zones in the coastal oceans have spread exponentially since the 1960s and have serious consequences for ecosystem functioning. The formation of dead zones has been exacerbated by the increase in primary production and consequent worldwide coastal eutrophication fueled by riverine runoff of fertilizers and the burning of fossil fuels. Enhanced primary production results in an accumulation of particulate organic matter, which encourages microbial activity and the consumption of dissolved oxygen in bottom waters. Dead zones have now been reported from more than 400 systems, affecting a total area of more than 245,000 square kilometers, and are probably a key stressor on marine ecosystems.

Supporting Online Material for Spreading Dead Zones and Consequences for Marine Ecosystems

Gene families are growing rapidly, but standard methods for inferring phylogenies do not scale to alignments with over 10,000 sequences. We present FastTree, a method for constructing large phylogenies and for estimating their reliability. Instead of storing a distance matrix, FastTree stores sequence profiles of internal nodes in the tree. FastTree uses these profiles to implement neighbor-joining and uses heuristics to quickly identify candidate joins. FastTree then uses nearest-neighbor interchanges to reduce the length of the tree. For an alignment with N sequences, L sites, and a different characters, a distance matrix requires O(N^2) space and O(N^2 L) time, but FastTree requires just O( NLa + N sqrt(N) ) memory and O( N sqrt(N) log(N) L a ) time. To estimate the tree's reliability, FastTree uses local bootstrapping, which gives another 100-fold speedup over a distance matrix. For example, FastTree computed a tree and support values for 158,022 distinct 16S ribosomal RNAs in 17 hours and 2.4 gigabytes of memory. Just computing pairwise Jukes-Cantor distances and storing them, without inferring a tree or bootstrapping, would require 17 hours and 50 gigabytes of memory. In simulations, FastTree was slightly more accurate than neighbor joining, BIONJ, or FastME; on genuine alignments, FastTree's topologies had higher likelihoods. FastTree is available at http://microbesonline.org/fasttree.

/pdf/fast-tree-computing-large-minimum-evolution-trees-with-4grq0gwfpy.pdf

Fast Tree: Computing Large Minimum-Evolution Trees with Profiles instead of a Distance Matrix

Since the IPCC Third Assessment Report (TAR), our understanding of the implications of climate change for coastal systems and low-lying areas (henceforth referred to as ‘coasts’) has increased substantially and six important policy-relevant messages have emerged. Coasts are experiencing the adverse consequences of hazards related to climate and sea level (very high confidence). Coasts are highly vulnerable to extreme events, such as storms, which impose substantial costs on coastal societies [6.2.1, 6.2.2, 6.5.2]. Annually, about 120 million people are exposed to tropical cyclone hazards, which killed 250,000 people from 1980 to 2000 [6.5.2]. Through the 20th century, global rise of sea level contributed to increased coastal inundation, erosion and ecosystem losses, but with considerable local and regional variation due to other factors [6.2.5, 6.4.1]. Late 20th century effects of rising temperature include loss of sea ice, thawing of permafrost and associated coastal retreat, and more frequent coral bleaching and mortality [6.2.5]. Coasts will be exposed to increasing risks, including coastal erosion, over coming decades due to climate change and sea-level rise (very high confidence). Anticipated climate-related changes include: an accelerated rise in sea level of up to 0.6 m or more by 2100; a further rise in sea surface temperatures by up to 3°C; an intensification of tropical and extratropical cyclones; larger extreme waves and storm surges; altered precipitation/run-off; and ocean acidification [6.3.2]. These phenomena will vary considerably at regional and local scales, but the impacts are virtually certain to be overwhelmingly negative [6.4, 6.5.3].

https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1192&context=scipapers

Coastal systems and low-lying areas

A positive temperature coefficient is the term which has been used to indicate that an increase in solubility occurs as the temperature is raised, whereas a negative coefficient indicates a decrease in solubility with rise in temperature.

Effect of Temperature

. Small mountainous rivers (SMRs) are important conveyors of the land-to-ocean organic carbon export. However, relatively few studies have focused on dissolved organic carbon (DOC) compared to particulate organic carbon. In a long-term project (2002 to 2014), stream DOC was monitored in three neighboring subtropical small mountainous rivers of Taiwan. The objective was to relate DOC concentrations to water discharge and to quantify DOC flux during typhoon and non-typhoon periods. Seasonal fluctuations of DOC concentrations were closely correlated with air temperature at all sampling stations. During non-typhoon periods, increasing water discharge led to decreasing DOC concentrations due to a dilution effect. However, during typhoon periods, DOC concentrations increased with some lead time along the hydrograph and reached the annual maximum which likely sources from a significant input of litter and upper soil layers. The mean DOC concentration of the studied systems (

/pdf/the-dynamics-and-export-of-dissolved-organic-carbon-from-40aukoqzt0.pdf

The dynamics and export of dissolved organic carbon from subtropicalsmall mountainous rivers during typhoon and non-typhoon periods

The seasonal dynamics of Cylindrospermopsis raciborskii was investigated from June 2011 to December 2013 in a small artificial pond in northern Taiwan. The abundance of C. raciborskii increased from late February to early April 2012 when the water temperature ranged from 16.4 to 21.7°C and from mid-August 2012 to mid-February 2013 as the water temperature decreased from about 27°C to below 20°C; it peaked in mid-February 2013 when the water temperature was 16.3°C. In the summer months, the abundance of C. raciborskii was very low and sometimes undetectable. A laboratory experiment using a strain that was isolated from the pond suggested that the dominance of C. raciborskii in low-temperature seasons could be attributed to its tolerance of, not preference for, low temperatures. Contrary to the results of this study, our earlier survey conducted in the same pond from August 2009 to January 2011 showed that the abundance of C. raciborskii was low in winter and increased in summer. Environmental changes in the study pond and/or the appearance of a different ecotype was assumed to be responsible for the change in the dynamics of C. raciborskii .

/pdf/appearance-of-cylindrospermopsis-raciborskii-in-winter-in-an-2xubthxwdz.pdf

Appearance of Cylindrospermopsis raciborskii in winter in an artificial pond in northern Taiwan

Predator and prey α-diversities are often positively associated; yet, understandings of the underlying mechanisms require manipulative experiments and thus remain unclear. We attempt to address this issue by deciphering how α-diversity of predator and prey influences each other’s community assembly processes, which subsequently determine their α-diversity. The occurrence of assembly processes was indicated by the mean pairwise taxonomic index within a community (αMPTI), assuming assembly processes left traceable imprints on species’ phylogeny. Specifically, αMPTI quantifies deviations of observed phylogenetic distances from that of random, so that it can be used to hint at the occurrence of non-random/deterministic assembly processes. Larger αMPTI of a community implies the occurrence of weaker homogenizing deterministic assembly processes, which suggests that this community might be comprised of less similar species and thus has higher α-diversity. We hypothesize that higher predator and prey α-diversity would be positively associated with each other’s αMPTI, which would then be positively associated with their α-diversity. To test the hypothesis, we calculated Shannon diversity and αMPTI for heterotrophic nanoflagellates (HNF; predator) and bacteria (prey) communities in the East China Sea. The HNF Shannon diversity was found to be positively associated with αMPTI of bacteria, which was then positively associated with bacterial Shannon diversity. In contrast, bacterial Shannon diversity did not correlate with HNF’s αMPTI. We argue that top-down control is one of the explanations to the positive α-diversity association among trophic levels in microbes of the East China Sea.

/pdf/community-assembly-processes-as-a-mechanistic-explanation-of-1l28g531xk.pdf

Fuh-Kwo Shiah

Papers

The dynamics and export of dissolved organic carbon from subtropicalsmall mountainous rivers during typhoon and non-typhoon periods

Appearance of Cylindrospermopsis raciborskii in winter in an artificial pond in northern Taiwan

Community Assembly Processes as a Mechanistic Explanation of the Predator-Prey Diversity Relationship in Marine Microbes

Activity and distribution of att ached bacteria in

Isotope constraints on the sources of particulate organic carbon in a subtropical deep reservoir