Skip to main content

Aquatic Dead Zones

Aquatic Dead Zones

The size and number of marine dead zones—areas where the deep water is so low in dissolved oxygen that sea creatures can’t survive—have grown explosively in the past half-century. Red circles on this map show the location and size of many of our planet’s dead zones. Black dots show where dead zones have been observed, but their size is unknown.


It’s no coincidence that dead zones occur downriver of places where human population density is high (darkest brown). Some of the fertilizer we apply to crops is washed into streams and rivers. Fertilizer-laden runoff triggers explosive planktonic algae growth in coastal areas. The algae die and rain down into deep waters, where their remains are like fertilizer for microbes. The microbes decompose the organic matter, using up the oxygen. Mass killing of fish and other sea life often results.

Satellites can observe changes in the way the ocean surface reflects and absorbs sunlight when the water holds a lot of particles of organic matter. Darker blues in this image show higher concentrations of particulate organic matter, an indication of the overly fertile waters that can culminate in dead zones.

Naturally occurring low-oxygen zones are regular features in some parts of the ocean. These coastal upwelling areas, which include the Bay of Bengal and the Atlantic west of southern Africa, are not the same as dead zones because their bottom-dwelling marine life is adapted to the recurring low-oxygen conditions. However, these zones may grow larger with the additional nutrient inputs from agricultural runoff.

Diaz, R. J., & Rosenberg, R. (2008). Spreading Dead Zones and Consequences for Marine Ecosystems. Science, 321(5891), 926-929 Via Earth Observatory

This post may contain affiliate links. As an Amazon Associate, I earn from qualifying purchases.


Comments

Popular posts from this blog

Moose population in North America

The moose ( Alces alces ) is the largest member of the deer family, characterized by its massive size, long legs, and distinctive broad, palmate antlers found in males. They have a dark brown or black coat and a humped shoulder. Moose are primarily found in the boreal and mixed deciduous forests of North America, Europe, and Asia. They are solitary animals, often found near bodies of water, and are herbivores that feed on leaves, bark, twigs, and aquatic vegetation. Despite their size, moose are strong swimmers and can run up to 35 miles per hour. The moose population in North America is shrinking swiftly. This decrease has been correlated to the opening of roadways and landscapes into this animal's north range.   In North America, the moose range includes almost all of Canada and Alaska, the northern part of New England and New York, the upper Rocky Mountains, northern Minnesota and Wisconsin, Michigan's Upper Peninsula, and Isle Royale.    In 2014-2015, the North American moo

Map of Fox Species Distribution

Foxes are small to medium-sized members of the Canidae family, which also includes wolves, dogs, and other related animals. There are about 37 species of foxes distributed around the world, and they inhabit a wide range of environments, from forests and grasslands to deserts and urban areas. Below is the map of fox species distribution  created by Reddit user isaacSW Here are some of the most well-known fox species and their distribution: Red Fox ( Vulpes vulpes ): The red fox is one of the most widely distributed fox species and is found in North America, Europe, Asia, and parts of North Africa. They are adaptable and can live in a variety of habitats, including forests, grasslands, and urban areas. Arctic Fox ( Vulpes lagopus ): The Arctic fox is found in the Arctic regions of North America, Europe, and Asia. They have adaptations that help them survive in cold climates, such as a thick coat that changes color with the seasons. Gray Fox ( Urocyon cinereoargenteus ): The gray fox

Find cities with similar climate

This map has been created using The Global environmental stratification. The Global environmental stratification (GEnS), based on statistical clustering of bioclimate data (WorldClim). GEnS, consists of 125 strata, which have been aggregated into 18 global environmental zones (labeled A to R) based on the dendrogram. Interactive map >> Via www.vividmaps.com Related posts: -  Find cities with similar climate 2050 -  How global warming will impact 6000+ cities around the world?