Long-term nutrient addition increases respiration and nitrous oxide emissions in a New England salt marsh.

Salt marshes may act either as greenhouse gas (GHG) sources or sinks depending on hydrological conditions, vegetation communities, and nutrient availability. In recent decades, eutrophication has emerged as a major driver of change in salt marsh ecosystems. An ongoing fertilization experiment at the Great Sippewissett Marsh (Cape Cod, USA) allows for observation of the results of over four decades of nutrient addition.

Effect of growth temperature on photosynthetic capacity and respiration in three ecotypes of .

Ecotypic differentiation in the tussock-forming sedge has led to the development of populations that are locally adapted to climate in Alaska's moist tussock tundra. As a foundation species, plays a central role in providing topographic and microclimatic variation essential to these ecosystems, but a changing climate could diminish the importance of this species. As Arctic temperatures have increased, there is evidence of adaptational lag in , as locally adapted ecotypes now exhibit reduced population growth rates.

Ecotypic differences in the phenology of the tundra species reflect sites of origin.

is a tussock-forming sedge that contributes significantly to the structure and primary productivity of moist acidic tussock tundra. Locally adapted populations (ecotypes) have been identified across the geographical distribution of ; however, little is known about how their growth and phenology differ over the course of a growing season. The growing season is short in the Arctic and therefore exerts a strong selection pressure on tundra species.