A rise in carbon emissions is not the only threat to the planet. Changes to the nitrogen cycle, caused in large part by the widespread use of fertilizers, are also damaging both water quality and aquatic life.
These concerns are highlighted by Professor Grace Brush, from Johns Hopkins University in Baltimore, USA, in her historical review(1) of landscape changes around Chesapeake Bay, a large estuary on the Atlantic coast of the USA. Her findings are published online this week in Springer's journal Estuaries and Coasts.Professor Brush studied the organisms and materials preserved in sediments in Chesapeake Bay spanning 1000 to 14,000 years, alongside available historical records covering the past 300 years, to trace the history of changes to nitrogen loading in the estuary. She highlights how population growth, agricultural expansion, and urbanization have released nitrogen from the land and moved it to Chesapeake Bay, where it has accumulated and degraded both the natural wildlife and water
The combination of the increasing use of fertilizers, deforestation and the draining of wetlands and floodplains to provide more land for crops, has led to an imbalance in the nitrogen cycle, in particular reduced opportunities for the natural removal of nitrogen. As a result, there is an excess of nitrogen in the estuary, also known as eutrophication. This in turn has led to the deterioration of the local ecosystem through reduced concentrations of oxygen in the bay, affecting both the water quality and the fish populations.
Providing food for an increasing population is the main reason for these changes, according to Professor Brush. Although the estuary supplied an abundance of fish species, humans also need plant-based food products in their diets, hence the increase in grasslands and use of fertilizers. She adds that aquatic deterioration is not unique to Chesapeake but a global phenomenon. Marine "dead zones" with low oxygen and/or toxic algae, caused primarily by the run-off of fertilizers from the land, as well as a greater reliance on fossil fuel, are on the increase.
Professor Brush concludes her review by looking at the likely implications of this imbalanced nitrogen cycle on future ecosystems as well as ways to improve water quality. She recommends multiple processes to reduce nitrogen accumulation, both natural and engineered, and notes that ultimately the decision to proceed will come down to politics.
Brush comments, "The future of the Chesapeake and coastal regions in general will depend very much on the recognition of the importance of nitrogen removal for goals other than restoring the fishery, how successful the various tools for nitrogen removal are, and the willingness of the public to pay for the implementation of those tools that can successfully achieve multiple goals."Reference
Joan Robinson | alfa
Value from wastewater
16.08.2017 | Hochschule Landshut
Species Richness – a false friend? Scientists want to improve biodiversity assessments
01.08.2017 | Carl von Ossietzky-Universität Oldenburg
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
17.08.2017 | Earth Sciences
17.08.2017 | Life Sciences
17.08.2017 | Materials Sciences