Skip to main content

Fertilizers as an increasing threat to the sea life

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 of landscape changes around Chesapeake Bay, a large estuary on the Atlantic coast of the USA. 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 quality.

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.”
Source: Springer & Maryland Natural Resources.
Labels:

Comments

Post a Comment

Popular posts from this blog

Regulated deficit irrigation, new recommendations for grape cultivation

The inland areas of the Pacific Northwest, where rainfall averages only 4 to 12 inches per year, present growing challenges for vineyard owners and wine grape producers. The arid conditions in this part of the country have not been conducive for vineyard owners who produce and market high-quality wine grapes. To promote healthy grape production when nature fails to deliver, vineyard managers in the area typically employ an irrigation practice known as “regulated deficit irrigation”. More than 60% of the wine grapes in the state of Washington are grown using this drip irrigation method. Unfortunately, the current irrigation methods are replete with problems that can cause over-irrigation and compromised grape quality. Recently, researchers at Washington State University’s Irrigated Agriculture Research and Extension Center completed a study that should provide vineyard managers new techniques for producing healthy and long-lasting grape crops. Joan R. Davenport was the lead author of th...
2 comments
Read more

Discovery of the missing link in spider evolution

New interpretations of fossils have revealed an ancient missing link between today’s spiders and their long-extinct ancestors. The research by scientists at the University of Kansas and Virginia’s Hampden-Sydney College may help explain how spiders came to weave webs. The research focuses on fossil animals called Attercopus fimbriunguis. While modern spiders make silk threads with modified appendages called spinnerets, the fossil animals wove broad sheets of silk from spigots on plates attached to the underside of their bodies. Unlike spiders, they had long tails. The research findings by Paul Selden, the Gulf-Hedberg Distinguished Professor of Invertebrate Paleontology in the Department of Geology at KU, and William Shear, the Trinkle Professor of Biology at Hampden-Sydney College, were published this week in the Proceedings of the National Academy of Sciences. New interpretations of fossils have revealed an ancient missing link between today's spiders and their long-extinct ances...
Post a Comment
Read more

Intense pressure to stimulate new cartilage growth, new hope for arthritis patients

Bioengineers at Rice University have discovered that intense pressure -- similar to what someone would experience more than a half-mile beneath the ocean's surface -- stimulates cartilage cells to grow new tissue with nearly all of the properties of natural cartilage. The new method, which requires no stem cells, may eventually provide relief for thousands of arthritis sufferers. "This tissue-engineering method holds promise not only for cartilage but also for tissues to repair bladders, blood vessels, kidneys, heart valves, bones and more," said lead researcher Kyriacos Athanasiou, Rice's Karl F. Hasselmann Professor of Bioengineering. The findings appear in the journal PLoS ONE. They are the latest from the emerging field of tissue engineering, a new discipline that aims to capitalize on the body's innate healing abilities to develop new ways of growing tissues that can be used to surgically repair wounds without risk of rejection. Cartilage, a tissue in the hum...
Post a Comment
Read more