Long‐term nitrogen loading alleviates phosphorus limitation in terrestrial ecosystems

Forest vegetation plays a key role in the cycling of mercury (Hg) and organic matter (OM) in terrestrial ecosystems. Litterfall has been indicated as the major transport vector of atmospheric Hg to forest soils, which is eventually transported and stored in the sediments of forest lakes. Hence, it is important to understand how changes in forest vegetation affect Hg in soil and its biogeochemical cycling in lake systems. We investigated the pollen records and the geochemical compositions of sediments from two lakes (Schurmsee and Glaswaldsee) in the Black Forest (Germany) to evaluate whether long-term shifts in forest vegetation induced by climate or land use influenced Hg accumulation in the lakes. We were particularly interested to determine whether coniferous forests were associated with a larger export of Hg to aquatic systems than deciduous forests. Principal components analysis followed by principal component regression enabled us to describe the evolution of the weight of the latent processes determining the accumulation of Hg over time. Our results emphasize that the in-lake uptake of Hg during warm climate periods, soil erosion after deforestation and emissions from mining and other human activities triggered changes in Hg accumulation during the Holocene stronger than the changes caused by forest vegetation alone.

Download Full-text

Declines in an abundant aquatic insect, the burrowing mayfly, across major North American waterways

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1913598117 ◽

2020 ◽

Vol 117 (6) ◽

pp. 2987-2992 ◽

Cited By ~ 12

Author(s):

Phillip M. Stepanian ◽

Sally A. Entrekin ◽

Charlotte E. Wainwright ◽

Djordje Mirkovic ◽

Jennifer L. Tank ◽

...

Keyword(s):

Mississippi River ◽

Animal Movement ◽

Aquatic Insect ◽

Terrestrial Ecosystems ◽

Trophic Levels ◽

Western Lake ◽

Annual Biomass ◽

Emergence Event ◽

Western Lake Erie

Seasonal animal movement among disparate habitats is a fundamental mechanism by which energy, nutrients, and biomass are transported across ecotones. A dramatic example of such exchange is the annual emergence of mayfly swarms from freshwater benthic habitats, but their characterization at macroscales has remained impossible. We analyzed radar observations of mayfly emergence flights to quantify long-term changes in annual biomass transport along the Upper Mississippi River and Western Lake Erie Basin. A single emergence event can produce 87.9 billion mayflies, releasing 3,078.6 tons of biomass into the airspace over several hours, but in recent years, production across both waterways has declined by over 50%. As a primary prey source in aquatic and terrestrial ecosystems, these declines will impact higher trophic levels and environmental nutrient cycling.

Download Full-text

Global meta-analysis shows pervasive phosphorus limitation of aboveground plant production in natural terrestrial ecosystems

Nature Communications ◽

10.1038/s41467-020-14492-w ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 18

Author(s):

Enqing Hou ◽

Yiqi Luo ◽

Yuanwen Kuang ◽

Chengrong Chen ◽

Xiankai Lu ◽

...

Keyword(s):

Meta Analysis ◽

Terrestrial Ecosystems ◽

Phosphorus Limitation ◽

Plant Production

Download Full-text

Climate Data Records of Vegetation Variables from Geostationary SEVIRI/MSG Data: Products, Algorithms and Applications

Remote Sensing ◽

10.3390/rs11182103 ◽

2019 ◽

Vol 11 (18) ◽

pp. 2103 ◽

Cited By ~ 3

Author(s):

Francisco Javier García-Haro ◽

Fernando Camacho ◽

Beatriz Martínez ◽

Manuel Campos-Taberner ◽

Beatriz Fuster ◽

...

Keyword(s):

Land Surface ◽

Expert Knowledge ◽

Terrestrial Ecosystems ◽

Environmental Applications ◽

Climate Data ◽

Area Index ◽

Infrared Imager ◽

Statistical Relationships ◽

Spectral Mixture

The scientific community requires long-term data records with well-characterized uncertainty and suitable for modeling terrestrial ecosystems and energy cycles at regional and global scales. This paper presents the methodology currently developed in EUMETSAT within its Satellite Application Facility for Land Surface Analysis (LSA SAF) to generate biophysical variables from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) on board MSG 1-4 (Meteosat 8-11) geostationary satellites. Using this methodology, the LSA SAF generates and disseminates at a time a suite of vegetation products, such as the leaf area index (LAI), the fraction of the photosynthetically active radiation absorbed by vegetation (FAPAR) and the fractional vegetation cover (FVC), for the whole Meteosat disk at two temporal frequencies, daily and 10-days. The FVC algorithm relies on a novel stochastic spectral mixture model which addresses the variability of soils and vegetation types using statistical distributions whereas the LAI and FAPAR algorithms use statistical relationships general enough for global applications. An overview of the LSA SAF SEVIRI/MSG vegetation products, including expert knowledge and quality assessment of its internal consistency is provided. The climate data record (CDR) is freely available in the LSA SAF, offering more than fifteen years (2004-present) of homogeneous time series required for climate and environmental applications. The high frequency and good temporal continuity of SEVIRI products addresses the needs of near-real-time users and are also suitable for long-term monitoring of land surface variables. The study also evaluates the potential of the SEVIRI/MSG vegetation products for environmental applications, spanning from accurate monitoring of vegetation cycles to resolving long-term changes of vegetation.

Download Full-text

Long-Term (2001–2020) Nutrient Transport from a Small Boreal Agricultural Watershed: Hydrological Control and Potential of Retention Ponds

Water ◽

10.3390/w12102731 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2731

Author(s):

Sari Uusheimo ◽

Tiina Tulonen ◽

Jussi Huotari ◽

Lauri Arvola

Keyword(s):

Climate Change ◽

Total Nitrogen ◽

Total Phosphorus ◽

Nutrient Loading ◽

Nitrogen Loading ◽

Agricultural Watershed ◽

Weather Data ◽

Pond System ◽

Daily Weather Data

Agriculture contributes significantly to phosphorus and nitrogen loading in southern Finland. Climate change with higher winter air temperatures and precipitation may also promote loading increase further. We analyzed long-term nutrient trends (2001–2020) based on year-round weekly water sampling and daily weather data from a boreal small agricultural watershed. In addition, nutrient retention was studied in a constructed sedimentation pond system for two years. We did not find any statistically significant trends in weather conditions (temperature, precipitation, discharge, snow depth) except for an increase in discharge in March. Increasing trends in annual concentrations were found for nitrate, phosphate, and total phosphorus and total nitrogen. In fact, phosphate concentration increased in every season and nitrate concentration in other seasons except in autumn. Total phosphorus and total nitrogen concentrations increased in winter as well and total phosphorus also in summer. Increasing annual loading trend was found for total phosphorus, phosphate, and nitrate. Increasing winter loading was found for nitrate and total nitrogen, but phosphate loading increased in winter, spring, and summer. In the pond system, annual retention of total nitrogen was 1.9–4.8% and that of phosphorus 4.3–6.9%. In addition, 25–40% of suspended solids was sedimented in the ponds. Our results suggest that even small ponds can be utilized to decrease nutrient and material transport, but their retention efficiency varies between years. We conclude that nutrient loading from small boreal agricultural catchments, especially in wintertime, has already increased and is likely to increase even further in the future due to climate change. Thus, the need for new management tools to reduce loading from boreal agricultural lands becomes even more acute.

Download Full-text