Life began in oceans and all life continues to depend on a healthy ocean environment. Oceans are important players in the carbon cycle and are major determinants of climate and weather patterns. Climate change is raising ocean temperatures. Rising levels of carbon dioxide are acidifying the oceans with adverse changes in aquatic ecosystems, threatening, for example, fisheries an important source of human food. 230,000 known species live in oceans. Two million marine species are estimated to exist. Oceans contain 97% of Earth's water covering 71% of Earth's surface.
The energy that is released by destructive hurricanes was stored in ocean water. This dramatic expression of weather occurs over the oceans. Cyclones are called hurricanes in the Atlantic Ocean. Cyclones form over warm ocean water usually 80 degrees F. and greater than 200 meters deep. With increased global ocean temperature rise, the main feature of global warming, hurricanes are becoming more frequent, wider and more ferocious. Heat evaporates water which rises and cools to saturation, condensing into clouds and rain. A hurricane combines thunderstorms, strong winds, rain, high waves, storm surges and tornadoes.
Warming of ocean water is having a worldwide negative impact on ocean life.
The world’s largest coral reef which stretches for over 1,400 miles off the
coast of Australia, has been severely affected by rising water temperatures. In
May 2016, researchers found more than a third of corals in central and northern
parts of the reef had been killed and 93 percent of individual reefs had been
affected by coral bleaching, where too warm water causes corals to expel algae
living in their tissue and turn completely white. Corals depend on a symbiotic
relationship with algae-like single cell protozoa, so when these are expelled
the corals stop growing and often die. [i] Coral reefs are
an important habitat for many fish species who die when the coral dies.
Among the numerous problems that arise with ocean warming, the increased in toxic phytoplankton threatens human and animal health. In the USA, NOAA has undertaken a study of algae blooms in the ocean. Linking warming to increasing phytoplankton toxicity. Domoic acid, produced by certain types of marine algae, can accumulate in shellfish, fish and other marine animals. Consuming enough of the toxin can be harmful or even fatal. Public health agencies and seafood managers monitor toxin levels and impose harvest closures where necessary to ensure that seafood remains safe to eat. NOAA is supporting research to help seafood industry managers stay ahead of harmful algae events that are increasing in frequency, intensity and scope.” Commercial and recreational shellfish fisheries along the US West Coast are a multi-million dollar industry," said NOAA harmful algal bloom program manager Marc Suddleson. "Improving our ability to accurately predict algal toxin levels in shellfish supports timely and targeted fishery closures or openings, essential to avoiding economic disruption and safeguarding public health." In 2015, domoic acid-related closures led to a decline in value of nearly $100 million for the West Coast Dungeness crab fishery according to the Fisheries of the U.S. Report 2015.
Another cause of phytoplankton blooms in increased nitrogen flowing into oceans from the land. Nitrogen in ocean waters fuels the growth of two toxic phytoplankton species, Pseudo-nitzschia pseudodelicatissima complex: P. cuspidata and P. fryxelliana that are harmful to marine life and human health. Auro and Cochland explained that nitrogen entering the ocean -- whether through natural processes or pollution -- boosts the growth and toxicity of a group of phytoplankton that can cause the human illness amnesic shellfish poisoning. Pseudo-nitzschia genus produce domoic acid. When these phytoplankton grow rapidly into massive blooms, high concentrations of domoic acid put human health at risk if it accumulates in shellfish. It can also cause death and illness among marine mammals and seabirds that eat small fish that feed on plankton.