most areas of the world where rainfall is limiting are characterized by low agricultural output and, ironically, high population growth rates that generate increased food de-mand. arid and semi-arid regions permit a range of vegetative biomass production, from rainfed crops to native pasture, and sparse steppe shrubs to true desert. given the harsh climatic conditions in areas such as west asia...

Bacteriophages are the most abundant organisms on the planet and play crucial roles in bacterial population dynamics, microbial food webs, and nutrient cycling. Understanding models of bacteriophage population dynamics is necessary to fully understand these ecological processes, but to do so we must mathematically distinguish between the different virus life cycles. Here, we build on two three-...

Tropical forests store large amounts of biomass despite they generally grow in nutrient-poor soils, suggesting that the role of soil characteristics in the structure and dynamics of tropical forests is complex. We used data for >34 000 trees from several permanent plots in French Guiana to investigate if soil characteristics could predict the structure (tree diameter, density and aboveground bi...

We add an ecosystem perspective to spatially structured communities subject to colonization-extinction dynamics. We derive a plant-based metaecosystem model to analyze how the spatial flows of the biotic and abiotic forms of a limiting nutrient affect persistence and coexistence. We show that the proportion of patches supporting plants in a region has a considerable impact on local nutrient dyn...

Nutrient dynamics in streams has been an important topic of research since the 1960s. Here we review this topic and the significant role played by J-NABS in its development. We limit this review almost exclusively to studies of N and P because these elements have been shown to limit productivity in streams. We use the expression nutrient dynamics for studies that included some measures of biolo...

A model for nutrient-phytoplankton dynamics is constructed and analyzed. A theoretical analysis shows that changes in the nutrient input can significantly change the qualitative behavior of the phytoplankton dynamics. In particular, the behavior can change from asymptotically stable to periodic. Numerical solutions of the model are carried out for seasonal nutrient inputs of a range of differen...

We present a theory extending the source-sink concept with an ecosystem perspective. We analyze a model for meta-ecosystem dynamics in a heterogeneous environment to study how the spatial flows of materials such as inorganic nutrients and nutrients sequestered into producers, herbivores, and detritus affect the community dynamics. We show that spatial flows of an inorganic nutrient (direct nutr...

サンゴ礁が分布する熱帯・亜熱帯域は栄養塩濃度が著しく低く，継続的な観測地点も少ないため，その挙動を理解するには未だ研究の余地がある。塊状の造礁サンゴの骨格は樹木のように年輪を形成し，その地球化学分析によって低緯度域での栄養塩挙動を高時間解像度で復元することができる。本稿では，造礁サンゴ骨格の栄養塩指標であるバリウム／カルシウム比，カドミウム／カルシウム比，リン／カルシウム比，窒素同位体比の開発の履歴とその特徴を紹介し，これまで明らかになってきたサンゴ礁への栄養塩の起源とその時空間変化をまとめた。また，先行研究による造礁サンゴの窒素同位体比分布と硝酸濃度の分布を比較した結果，亜熱帯循環の縁辺部と内側では窒素同化と窒素固定がそれぞれ盛んに起こっており，栄養塩の供給源に違いがあることがわかった。さらに造礁サンゴ骨格の窒素同位体比から明らかになった北太平洋亜熱帯循環の西側縁辺部である黒潮流域...

Introduction Conclusions References