Seagrasses help to protect human and coral reef health by reducing levels of disease causing pathogens

​There’s a new reason to value seagrasses, and to include them in coastal restoration and mitigation- human health.  Seagrasses reduce the abundance of disease causing pathogens.
 
Seagrasses are know as vital nurseries for commercial fish, for their abilities to maintain beach sand, and are emerging as valuable assets in the blue carbon economy. In tropical waters, like the Caribbean Islands, they are closely associated with coral reefs and sea turtles and conch. Seagrasses have been in decline globally often associated with coastal development, including marinas and dredging of their habitat for ship channels.  In many States and island nations seagrass restoration has been required to mitigate damage or carried out by conservationists and or homeowners seeking to protect their property
A peer-reviewed study just published in Science* a team of scientists found that seagrass may benefits that we had not fully realized- human health.
In a peer review study recently published in Science a team of researchers found that

• Enterococcus bacteria levels in seawater were threefold lower when seagrass meadows were present compared to levels in water without seagrass. Enterococcus abundance is used as a standard indicator for wastewater pollution, because the bacteria are a source of multiple infections in humans and marine organisms. Similarly, seawater collected above the coral reefs adjacent to seagrass meadows had twofold lower levels of Enterococcus than reefs without adjacent seagrass.
• The abundance of 18 other disease-causing bacteria on intertidal flats was 50% lower within seagrass meadows compared to sites without seagrass, Likewise, pathogen levels were 50% lower in seawater from coral reefs adjacent to the seagrass meadows compared to reefs without seagrass.
• Seagrass benefits coral health too. The prevalence of coral disease was 50% less on reefs adjacent to seagrass meadows. Disease outbreak is a driver of reef loss globally. One bacteria, Serratia marcescens is linked to the decline of elkhorn (Acropora) the main reef-building corals found in US and Caribbean and now on the U.S. Endangered Species List

Sediment/sand retention by seagrass meadows could play the major role in reducing diseases. Higher sediment levels have been linked to two coral diseases.
How can this information make a difference?  Seagrass establishment can be incorporated into mitigation and restoration. For instance,
1. Seagrass Restoration in polluted areas - -  Seagrass can be successfully restored- there are several methods that that proven to work. For those involved in coastal and salt pond restoration, especially in areas of runoff or that are adjacent to septic issues, adding sea grass restoration could make the difference between healthy and unhealthy waters and beaches.
2. Coral Restoration: All around the tropics communities and governments are working to restore coral reefs and to stem the loss of existing corals. Disease is a major factor in coral decline.  Choosing restoration sites that are adjacent to coral reefs, or restoring seagrass adjacent to reefs could vastly increase the potential for coral recovery.
J. Lamb et al, Seagrass ecosystems reduce exposure to bacterial pathogens of humans, fishes, and invertebrates Science 17 Feb 2017: Vol. 355, Issue 6326, pp. 731-733 DOI: 10.1126/science.aal1956