For over a century, researchers detailed how eelgrass Zostera marina could sequester organic matter in shallow water. In 1915, P. B. Jensen of the Danish Biological Station determined that eelgrass was the source of over 100 grams of organic matter per square meter along the Danish Wadden sea coast. In 1925, The Treatise on Sedimentation (National Research Council USA) sought to bring international perspectives to a new concern about marine soils. A second effort organized in 1935 included the emerging research areas of sedimentation, bacteriology, chemistry and coastal processes. These areas were represented by papers authored by Lüders , Häntzschel, Strøm and Zobell circa 1938. The outbreak of World War II postponed publishing until Recent Marine Sediments with Parker D. Trask as editor in 1955. Kaare Münster Strøm’s summary of research in Norwegian fjords reviews coastal stagnation as how it relates to a “super abundance” of organic matter and the presence of hydrogen sulfide. The study period, however, was during a largely negative NAO, a period recognized for severe storms and colder temperatures. The NAO, North Atlantic Oscillation, was associated with changes in the wintertime polar circulation which changed in 1980 (Hurrell and H. Van Loon 1997).
Inshore fishers in New England USA also noticed significant habitat change in areas of tidal restrictions. Warmer winters created similar stagnation conditions described by Strø m (1938) although in much smaller systems than Norwegian fjords. Waterford, CT (USA) winter flounder fishers described sulfur smelling muck to town officials in 1981. Inshore fishery observations detailed a second major eelgrass die off in Niantic Bay between 1981 and 1985 following the records of Cottam – US Fish and Wildlife Service of a previous die off of eelgrass 1930 to 1935. Accounts from the shellfish industries (oyster, soft shell clam, bay scallop and hard clam) all mention eelgrass gaining habitat coverage with a transition of once firm or hard bottoms to these much softer and with the presence of hydrogen sulfide. Industry observations include areas of high sulfide with dead or dying shellfish with the presence of “off flavors” watery meats and poor-quality meats in general (Galtsoff 1937).
In 1985, Donald Rhoads of Yale University Department of Geology, described the formation of sapropels during prolonged heat and low dissolved oxygen. He termed them mono-sulfidic muds rich in sulfides with high organic contents (EPA-NOAA Workshop 1987) in western Long Island Sound. Long Island Sound is known for alluvial deposits containing high amounts of iron and organic matter capable of sustaining sulfate-reducing bacteria, a source of sulfide compounds known to weaken or kill submerged aquatic grasses (Pedersen et al. 2004), making warmer temperatures and high organic deposition key climate change indicators for eelgrass soil health and sulfide formation near its roots.
Sulfide toxicity is reviewed for west and east coast Atlantic eelgrass introducing sulfide toxicity as a response that indicates both being derived from the same parent root stock.