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Author Topic: #17-B The Sulfide Winter Kill of Blue Crabs Environment/Conservation #17-B  (Read 917 times)
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« on: April 12, 2019, 11:55:58 AM »

The Sulfide Winter Kill of Blue Crabs
Environment/Conservation #17-B
The Blue Crab ForumTM
The Cycle of Marsh Peat – Organic Matter and The Blue Crab
Sulfides, Spartina alterniflora and Sapropel – Bacteria
Metal Chelation and the Sulfur Cycle
View the Nitrogen/Bacteria EC Newsletters on the Environment Conservation Thread, The Blue Crab ForumTM
A Capstone Proposal 
December 2018
Tim Visel
The Sound School


An Introduction to this research area is found on EC #17-A posted on The Blue Crab ForumTM on October 25, 2018.  Reviewing 17-A provides the background material in this section.
 
Blue Crabs and Winter Kill

Most East Coast blue crabbers have heard or experienced winterkill – the observation of dead crabs in early spring.  I have seen dozens of crabs in spring mud, often surrounded by mud snails “killed” by something during the winter.  What actually killed the crabs?  Often, winterkill is associated with colder temperatures and ice and the possibility of ice freezing or creating ankle frost fresh water freezing in areas of groundwater percolation.  Another possibility is starvation – insufficient food reserves and long cool winters.  Yet a third possibility is toxic habitat conditions or disease.  Massive mortality is often reported after a harsh (extreme cold) or periods of long cold temperatures that extended into the traditional spring.  In the agriculture history terms, like early frost or cold snap describe events that shorten a growing season (See Florida The Great Freeze of Citrus Crop – 1894-1895 Orlando 18oF - West Palm Beach - 24oF for an excellent write-up of this).  In the fisheries literature, growing seasons and habitat clocks do not line up because of the differences in temperature – a sudden cold night in May can cause apple tree blossoms to fall but not even impact fishing because of the buffering effect of water.  It is much slower to absorb or release heat; one or two cold nights will not greatly change seawater temperatures but on land may quickly leave a coating of thick ice.

We have the ability to examine where blue crabs live in the marshes during summer above peat acid soil but dig into bottom sapropel composts in the winter.  Both habitats are subject to the sulfur cycle as they relate to oxygen levels.  In summer heats, there are more sulfides as warm water holds less oxygen and in cold as plankton activity diminishes lessens any fresh oxygen diffused into the water itself.  Cold isolated pockets of seawater may become oxygen-limited and sulfide-rich. 

On salt ponds with heavy ice, the oxygen depleted bottom waters become sulfide-rich and kill any surviving pockets of blue crabs.  “Open” winters are often quite different.  Oxygen is able to mix to the bottom during wind events and less sulfide can accumulate.  Fall winds help bottom water exchange, and it is the ecological world termed “fall overturn.”  If you ever witness an overturn on a lake, you will never forget it.  The water is frequently black or even green (some sulfur bacteria can produce green colors).  We can look to plant life in similar habitats to see how sulfides impact biological and reproduction functions.  Submerged vegetation, such as eelgrass, is impacted by the creation and destruction of sulfides; it lives on the oxygen edge of life near the sulfur cycle below it, vanquished long ago by the elemental oxygen in our atmosphere.  In waters with low oxygen, sulfur cycles can rebuild and become toxic to most oxygen life forms – as metal sulfides.  In high heat, they ever purge into sulfur aerosols, the smell of rotten eggs.  For many species, it is their tolerance to sulfides that allows them to live in “hot” organic peat, especially a peat surrounded or immersed in seawater saturated with sulfate.  Here the sulfur cycle waits for oxygen to run out, killing seafood in its path, we often call black or dead water.  Florida residents have witnessed the terrible impact of black water upon coastal sea life (See EC #13, posted July 13, 2016).

Introduction - Environmental Fisheries History

When I do a review of the literature before completing an article I seek papers from the 1980s, first it represents the transition post 1972 of a positive NAO – a long-term gradual climate warming here that saw frequent droughts warmer winters and very hot summers.  The waters, however, were still relatively cool in the 1980s.  The second reason is also the transition of science research from federal civil service to a type of outsourcing or pass through agency research funding to non government sources – Universities or NGO, a “non government organization.”  Here we have environmental missions intersecting science as brought out in articles by John Teal and Scott Nixon in the 1980s.   These publications frequently include the disclaimer such as the one below.  “The findings in this report are not to be construed as an official U.S. Fish and Wildlife Service position unless so designated by other authorized documents.” (Nixon, S.W., 1982, The Ecology of New England High Salt Marshes)

After 2000, some evidence of the mission effect is seen by that grant funded research that often represents the position or viewpoint of the grant funding agency by policy or mission statement similar to the so called “funding effect.”  Such research, especially those about habitat/species, typically are very short in duration and reflect a “snap shot” bias, giving the impression that shallow habitats are static and, therefore, a permanent value can be assessed.  They also contain a climate bias if not measured over long periods of time for temperature.   A third impact is habitat stability, which is important to our survival and is called the “normalcy bias.”  This is illustrated with the number of eelgrass reports that promote conservation policy but that exclude the eelgrass sulfur cycle in heat – hot seawater below them or the impacts of natural storm energy.  Recently I do see examples of eelgrass papers now beginning to include the sulfur cycle or the harmful impacts of sulfate/cellulose metabolism of submerged aquatic vegetation in marine soils from the bacterial formation of sulfides.  That is a very good sign that this problem is subsiding.

To learn more about the habitats in which blue crabs live, we can look at other species, such as plants, to see if they have special features that allow them to live in peat/sapropel acid soils in which blue crabs also live – the plants of coastal peat.  So when during one of searches I came across a study of Spartina alterniflora, a plant that does not live with eelgrass on the bottom, nor exposed to air directly (oxygen) as Spartina patens is on a salt marsh surface peat – I often look to the date to see if it is from the 1980’s. This plant, Spartina alterniflora, must have certain life functions that allow it to “live in the middle” between a submerged grass (eelgrass) and less oxygen at times and exposure to much oxygen – a “surface grass,” such as salt marsh Spartina patens, a plant in the middle between oxygen and sulfuric acid sulfides of sapropel before it contains roots and becomes a peat, or often a submerged seagrass.  Included in the chemistry of peat is the nitrogen, sulfur and carbon cycles and the ability of various bacteria to gain energy from metal oxides and chelate metal ions.  Many of these bacterial chemical reactions are governed by the absence or presence of oxygen.  It is the oxygen level of peat or sapropel that drives the chemistry so important to understanding the habitat impacts of heat and cold upon blue crab habitat conditions.

A large body of research exists in regards to plant life in relation to terrestrial soils – which soils hold moisture, which tend to be acid or alkaline or those that need organic matter.  For marine soils, there exists far less research in terms of soil as most research refers to mixtures of sand, minerals and organic matter as fine grain sediment – not a soil.  Plants that live in coastal peat or submerged mixtures of sand and bits of calcium (bivalve shell) have many of the same terrestrial soil characteristics to those marine soils that contain clay, mixtures of sand and organic matter.  Marine (peat) soils can be very acid, in fact some of the most acid soils recorded by researchers – are called acid sulfate soils.  Many of the previous soil definitions were based upon the ability to access oxygen or pore space as well drained or poorly drained.  Marine soils, therefore, often do not fit; these soils obtain oxygen from water, not air, so the aspect of draining peat (most often to enhance soil water/air movement) cannot happen.  Marine soils are not leached by acid rain.  In fact, they obtain the metal and calcium ions leached from terrestrial soils to them.  Therefore, some of the essential plant ions, potassium, others such as sulfur, iron, aluminum and zinc elements, are not limiting.  Marine soils with high amounts of organic matter are often metal ion rich, and over time, show the bioaccumulation of metals in them by bacteria.  And many marine plants have adapted to these metal sulfides, especially the life functions of eelgrass. 

For instance, ecologists for decades have known that certain fresh water plants can soak up metal ions in peat such as the cattail, Typha latifolia.  Other plants share other growth characteristics, the sugar cane, Saccharum officinarum, is able to live in a high sulfur, high metals content peat, now often termed acid sulfate soil.  Although sugar cane culture in Florida’s everglades has been criticized for polluting water runoff, the sulfur and metal chelation aspects of this plant may, in fact, be one of the few options we have in reducing the toxic impacts of sulfides in black water, the leachates of peat soils in low oxygen “wet” conditions.  Sugar cane uses much water in its growth process and has adapted to high sulfur conditions and can complex heavy metals in its plant tissue.  Sugar cane can survive on acid sulfate soils if the peat is oxidized by a lowered water table.  Like the Phragmities reed, it helps lower the water table by building an organic layer between its stalks.  In times of drought, it is then susceptible to fires for the same reason.  A plant of the tropics, sugar cane is found growing naturally in acid sulfate soils (peat) in many areas. 

Marine soils rich in iron monosulphides have been studied by New England Agricultural Experiment Stations for over a century, and when harvested as a terrestrial soil manure, advised farmers to cut in lime or mix it with oyster shell (or other calcium shell) to offset a surge in sulfuric acid once exposed to oxygen (See Connecticut Agricultural Experiment Station Report #1, Annual Report of the Connecticut Agricultural Experiment Station for 1877, Essex, CT Samples, pg. 50).

Some researchers now noted that when marine soils are exposed to oxygen, the sulfide oxidation produces sulfuric acid so intense as to drive soil pH to levels as low as 2 (See McLeod’s Creek Study – New South Wales, Quick et al., 2016).   When submerged peat or sapropel appears blue and with the odor of sulfides, it is likely acid sulfate soil and one New England farmers learned about sometimes the “hard way” as one of my most often used quotes about sapropel usage comes from the town I live in today – Essex, CT.  Mr. Stevens remarks in an 1877 CT Agricultural Experiment Station Report:

“Our mill ponds a few miles back from the river contain a rich black mud, quite deep and with a very strong smell.  It has been tried on various crops but kills everything.”

Here, sapropels and humus of submerged composts were often mixed, surface humus (yet below water but exposed to some oxygen) gave at times a good carbon/metal ion mix and fed nitrate-producing bacteria quickly, which then improved ion levels needed by plants.  However, deep deposits high in sulfides, which when put on land literally “flashed” sulfuric acid, killing plants.  Only plants that can tolerate these aspects of the sulfur cycle can live in peat.  In many parts of the world, reed plants are being looked at as huge filters to remove chemicals and nitrogen from water, even our invasive Phragmites with nitrogen.  The chemistry of peat soils can provide information on how organisms have survived previous cold and warm (hot) cycles.  It is the hot cycles that show the greatest changes.  In seawater, sulfate is not limiting and lower oxygen levels enhanced bacterial action that turned peat back into sapropel.  The salt marshes would then sink.  That was observed in the 1890s.


Nixon, S. W., 1982.   The Ecology of New England High Salt Marshes: A Community Profile.  U.S. Fish and Wildlife Service, Office of Biological Services, Washington, D.C. FWS/OBS-81/55.  70 pp.

Evolving Concepts of Marsh Development

Subsidence and Sea Level Rise – The Mudge Model from Nixon (1982)

“In 1857, B. F. Mudge (1862) presented a paper to the Essex Institute in which he described his findings from a core taken in the Romney Marsh, near Lynn, Massachusetts, at a site “about one foot above ordinary high water mark and only overflowed by the higher spring tides.”  The remarkable feature of this core was that it showed the roots and rhizomes of the marsh grass extending down uniformly to a depth well below normal low tide.  Because the grasses grew only above the normal high water level, Mudge concluded that the marsh had been subsiding and that the subsidence had been counter balanced by an upward accretion from grass growth the subsequent sediment deposition.  The process responsible for the subsidence of the marsh was not known at the time, and Mudge speculated that it might be due to erosion beneath the marsh caused by a “current of water in the diluvium under the clay.”

These hot cycles could have dramatic impacts to salt marsh peat as well.  Nixon (1982) had assumed that increases in ocean volume (sea level rise) were more important than land or marsh subsidence for accretion rates or marsh upward growth called accretion patterns.  But these studies were in a period following a cool one, and as Nichols noted in the 1920s, hot marshes seemed to collapse leaving depressions or pannes behind.

But European studies do mention marshes that bubbled up sapropel called gyttja a Swedish term as a viscous liquid that formed deep in the peat.  In low oxygen conditions (heat) bacterial digestion of the marsh can occur below the oxic zone, and in time become unstable – a softening that with heat can lead to complete plant tissue digestion.

This occurs in heat and George E. Nichols (See Nichol’s quote was used in EC #11) gives us a look back at this process a century ago.

George E. Nichols, a botanist who wrote a bulletin for the Torrey Botanical Club in 1920 (The Vegetation of Connecticut), provides many clues to sulfate peat digestion (rotting) at the end of this very hot period 1880-1920.  On pages 531-532 (Nichols, The Vegetation of Connecticut) is found this section:
 
“There is one peculiar feature of the upper littoral marsh which has already been suggested, and that is the occurrence, scattered here and there in greater or less abundance over the surface, of shallow depressions (FIGS 7, 10), usually muddy or occupied by tidal pools at low tide, and strikingly different in the character of their vegetation from the adjoining higher and better drained parts of the meadow.  These salt meadow pools and “rotten spots” (technically termed “pannes” T.Visel), the origin of which will be described later, may lack vegetation entirely, so far as the higher plants and concerned; and, while the alkali grass is frequently present, the salt meadow grass and the black grass are almost invariably absent.  The character plants are usually two, namely the salt marsh grass and the samphire. Singly or in association, and not infrequently accompanied by the sea lavender (Limonium), these may predominate over considerable areas of undrained or poorly drained ground; but, even for them, the soil conditions are not wholly favorable* and very often they succumb to their manifestly unsuitable environment.  The salt marsh grass, in such situations, commonly assumes a low, impoverished habitat, often failing to flower, while samphire and sea lavender grow much less vigorously than on better drained soils, frequently exhibiting a very sickly appearance.”
 
And on page 545 – the origin of salt marsh depressions or pannes – mentions plant vegetation covered by loose vegetation smothering the existing plant cover (Johnson and York 1915):

“Subsequently (Johnson and York, 1915) he maintains, rapid decay sets it, affecting not only the aerial plant organs, but the underground parts as well, and eventually a depression of some depth may thus arise.”

Some of this was explained in the 1982 paper by Scott Nixon mentioned above.  In the literature (1982 to 1985) was a period of climate transition so papers written during this period is of high interest.

In my searches of information, I frequently check to see if other researchers had done previous research in the same or similar area – the oxygen levels of sapropel (sulfide ooze) and peat and their relationship to the growth of plants.  In this case, it was salt marsh peat.  After many months, I did get a list of titles, dating back to 1983.  One such title was “The Importance of Oxygen Diffusion Rates and Chemical Oxygen Demands in Influencing Vascular Plant Zonation Patterns on the Salt Marsh” as part of a 1983 NEERS conference, but nothing beyond a title.  Another search (aeration of salt marsh peat) turned it up again, this time with a cross reference to oxygen diffusion rates (ODR) into the peat – again an area of investigation underway, linking the oxygen movement in eelgrass root tissue to better growth and a decline in oxygen bacteria to eelgrass root failure, reflecting low oxygen levels in marine soils.  After many months, it came up again, this time with plants that respond to different oxygen levels as diffusion and chemical oxygen demands of peat but just the abstract, no author.  After a renewed search last spring (March, 2018), I finally was able to obtain the author, E. S. Yuhas, The Sound School Assistant Principal, with whom I share lunch supervision each day!  He was able to produce the entire report (similar to Sound School “Capstones” today) with a great reference list.  We both got a chuckle but what Eric did in 1983 is so appropriate today; a warming planet has a direct relationship to seawater oxygen content – diffusion or peat oxygen saturation for grasses, which live at times, submerged.  The amount of oxygen available on salt marsh/peat did influence growth of plants and the one subject to my current investigation of Spartina alterniflora, a plant that is on the surface peat of cordgrass and the submerged peat of eelgrass – increasing pore size in soil to gain additional oxygen - diffusion (See Conclusion in Appendix #1).  This paper looked at precisely that relationship that oxygen diffusion (availability) is important to salt marsh plants living in heat.

It is here we have a plant that has adapted to high sulfides and the sulfur cycle part of the height of a “tidal” day – the other exposed to oxygen (low tide).  Spartina alterniflora may become more of help in understanding habitat succession in heat more than eelgrass, Zostera marina.  One of the ways we can observe how these plants adapted to peat is simply by observing where they live.  This was the topic of Eric Yuhas’ paper.   I had also observed what happens to trees when the soil is permanently submerged – the tree dies.  Life however continues on the high organic mounds in salt marsh hummocks exposed to some oxygen.  Accounts of early European settlers marveled at the salt marshes here was an animal forage grass that grew without help and once drained harvested by the ton.  Over time, nature had created this drained effect, low tide, allowing oxygen to diffuse into the surface peat sometimes less than a foot.  The tidal salt plants growing in compost that has a surface monoculture we call salt hay.  Bottom composts not yet exposed to air also had value to agriculture, even though rich at times in sulfides, which you could smell as well on hot nights, “rotten eggs” were long used to nourish terrestrial soils.  It is this marine compost in which the blue crabs, at times, live and at others perish.

Just a few months after the NEER’s presentation by Eric Yuhas, another large estuary study was being completed and submitted by the University of Maryland Center for Environmental and Estuarine Studies by J. Court Stevenson titled “Investigation of Marsh Losses At Black Water Refuge” (1983).  This study was similar to one completed two decades earlier for Currituck Sound titled “Back Bay Currituck Sound Data Report: Introduction to Vegetative Studies 1958-1964.”  Most of the marsh studies in the 1940’s and 1950’s were conducted to improve waterfowl (duck) hunting by way of habitat (marsh) management and water ponding improvement.  In the historical marsh literature, two issues dominated: (1) the elimination of mosquito breeding habitats, and (2) the improvement of marshes to create waterfowl duck habitats – both in marshes and at times driven by public policy.  So, the disappearance of marshes was a concern to both hunters and naturalists in the 1950’s and the 1960’s as the feeding and breeding habitats make for great bird watching as well.  The draining of marshes to reduce mosquito populations and disease also continued, yet often opposed by duck hunters.

However, beginning in Southern areas, salt marshes started to sink based on two factors considered, continued sea level rise and marsh subsistence.  Many times, the core of salt marsh peat gave clues to both, the pollen grains of springs long ago lay trapped deep within salt marsh cores.  With the understanding that pollen is distributed by wind, the “surface” peat of prehistoric times now lie several feet below the current surface but not covered by water.  For those pollen grains to be so deep, new organic matter must accumulate above it and, in time, peat is digested back to mineral components plus the remains of hard to digest fats and oils.  It is difficult to imagine that coastal peat, which seems so firm, could at times become a loose jelly and sink.  I recall an account of a once large natural oyster reef in the salt pond in the upper reach of the Quinnipiac River in Fair Haven.  Here, tongers could take oysters along the banks of marsh peat, in some years thousands of bushels, but in the mid-1920’s, the oyster bed disappeared as if it had been a ship at sea going down.  According to George McNeil who had an oyster business (shop) at City Point, the bed sank in black ooze and where oystering had been good, nothing but the stems of plants and leaves were later caught in oyster tongs.  Such a core in this area would likely reveal a thick dense layer of oyster shell and a loose ooze below and above it.  What had once supported oyster setting in high heat became unstable as its peat base perhaps turned to jelly and could no longer support the weight of the oysters.  Once firm, peat, even subtidal, could be softened and oysters then sink.  Later, coastal core studies here in Connecticut in the 1990s often indicated evidence of these layers.  But what would cause this instability is a process as old as time itself, bacterial/chemical processes in peat, which in time became a sapropel.  Sections of oyster reefs exhibit this upward growth in slow climate transitions and can reach several feet deep (See “The American Oyster,” 1964, Vol. 64, Fishery Bulletin of the Fish & Wildlife Service, ” by Paul Galtsoff, pg. 19, figure 19).  In time, the weight of the reef itself, if on peat, can find itself not supported by the root mass of peat, but a jelly-like substance, and could smell of sulfur and sink.

In the historical literature, you can find reference to this sulfide ooze (black mayonnaise to fishers) but perhaps a true sapropel.  They were often described as mud or quicksand, a term used in the 1890’s to describe marsh softening.  Early peat examinations gave significant successional clues also mentioning oysters below the current peat surface, including this segment from The American Journal of Science 1897, Edward S. Dona, Editor, Fourth Series, Vol. IV, Pg. 76 [G.L. Wieland communicated about the depth of peat in the dismal swamp in Virginia]:

“During a recent visit to the dismal swamp region and Lake Drummond, I found that a section now to be obtained at the excavating just completed for a lock on the “Feeder Canal” about one-half mile east of Lake Drummond and at the very center of the swamp gives open testimony to the thickness of the peat accumulation and the origin of the lake.

These are about ten feet of peat containing many large rocks or even tree trunks, this followed by a layer of very clear peat, some eight feet in thickness, resting in a clear quick sand and containing marine shells.  Oyster and clam shell are quite numerous and very likely they could be obtained by dredging from the sandy bottom of the lake, which has a depth of about twenty feet.”

As a bonus reference to this oyster habitat/peat successional process is the 1897 Journal of Science of New Haven, CT published a reference by contributing Professors O.C. Marsh and A. E. Verrill (who would later publish many bulletins about shellfish) and H.S. Williams of New Haven, Fourth Eastern Series, Vol. IV, Tuttle Morehouse and Taylor Press (New Haven, CT) regarding changes in the Currituck Bay after an inlet was closed and habitat/species reversed from saline to fresh water species (the opposite of sea level rise impacts). 

“Currituck Sound Virginia and North Carolina: A Region of Environmental Change” by G.R. Weiland communicated:

“One of the most important geological changes, which has taken place along the Atlantic coast in recent time, was the closing up of the Currituck Inlet, North Carolina by drifting sands in 1828.  Previous to that year, this inlet formed such a passage from the ocean through a narrow outer beach into the waters of Currituck Sound as is formed by either the new or Ocracoke Inlet to Pamlico Sound.  Now with the dosing of the Currituck Inlet, there was the conversion of upwards of one hundred square miles of shallow salt to brackish water area to fresh water, and it is within the memory of men now living that the resultant changes were immediate and striking.

Previously, the sound had been a valuable oyster bed.  Within a few years, the oysters had all died out and their shells may now be seen in long rows where they have been thrown out in dredging for a boat way in the Coinjock Bay, a southwestern extension of the Sound.  Further, there were such changes in vegetation as brought countless thousands of ducks of species that had been only occasional before.

The saltwater fishes were driven out and fresh water fishes took their place.”   

The Black Water Maryland report (1983) looked at the disappearance of salt and brackish marsh at this reserve.  It is an extensive review, looking at many factors: road construction, the introduction of Nutria, the trapping of Muskrats, over-foraging of duck and waterfowl species, controlled burning, the growing of grain crops as supplemental winter forage grazing (for ducks), salinity changes, the use of herbicides, sea level rise, dredging, tide cycles, fertilization transplanting of Spartina alterniflora and other marsh plant species.  Of all the transplant trials, Spartina alterniflora “had the highest survival rate” (pg. 183), indicating to me the soil conditions were depleted in elemental oxygen and, most likely, bathed in sulfate.

Although soil peat conditions were mentioned in the executive summary, they were not a focus section of the study, which is a surprise considering the name of the refuge area itself has the term “Black Water,” part of its name indicative to peat/soil bacterial chemistry or the sulfur/ammonia pathway of sulfate-reducing bacteria versus the oxygen/nitrate pathway for the growth of plants.  Sea level rise combined with marsh peat bacterial digestion (slumping) is associated with increased sulfate availability and the formation of “black water.”  It is in this submerged peat that Alterniflora does so well; these are the sulfate acid soils.

The report on page 202 (Black Water Refuge Report) details this change from oxygenated peat (nitrate available) to sulfur peat (ammonia available) pathways and describes the peat soil change as “stagnation.”  Stagnation frequently occurs in the fisheries literature describing events just before fish kills (i.e., lack of flushing and thermal changes, usually heat – T. Visel):

“Largely circumstantial evidence implicates sea level increases, acting in concert with a lack of sediment accretion on the marsh surface, as a primary mechanism for gradual marsh deterioration and loss.  Under this hypothesized scenario, marsh interiors become sediment-starved and gradually subside, and lacking sufficient sediment for vertical accretion, would gradually become water logged and stagnant.  Resulting retardation of root growth or root death, and decomposition of the structural dead root component of the root mat would cause further subsidence, stagnation and disintegration of the marsh surface, conditions beyond the tolerances of the dominant plant species.”

In heat, salt marshes can sink and, in the process, shed sulfides.  “They sink” and now can enter the sulfur cycle.  This is a quote from a speech given by Reverend William Clift of Stonington, CT to Rhode Island farmers at the Rhode Island Horticultural (IMEP #26) Society Industrial Exhibition in Providence 1854.  Rev. Clift urged area farmers to take advantage of this marine mud (sapropel), to put some life and “energy” into New England’s thin and organic poor soils that in geologic time 10,000 years was still considered very “young.” My comments (T. Visel):
   
“The marine deposits in the bottoms of your bays, creeks and rivers are made up very largely of these decayed weeds; and could not fail to prove a valuable fertilizer and further “Dead forests of gigantic dimensions lie entombed in them (marine humus, T. Visel).  In these places the vegetable wealth of centuries is accumulated” and then in closure” let human skill breathe upon these reeking sepulchers of dead plants and they shall wake up again to life and beauty and fruit fullness.”

It is the “reeking sepulchers” that give the sulfide content away – sulfides smell “bad.”  The thin glacial soils did benefit from these surface humus deposits but deep sapropel sealed from planted oxygen accumulations had sulfuric acid releases, driving pH levels so low that at times crops were killed.  Termed Acid Sulfate Soils today farmer organizations and Agriculture Experiment Stations soon advised the farm community to cut in shell or lime to offset this at times “hurtful acidity” – caused by sulfate reducing bacteria living in them.

In 1885, the Maine Agricultural Experiment Station also warned of sealed or buried sapropel could shed ammonia.  A 1885 marine report of the Maine Experiment Station page 35 contains this note when sampling marine mud used as a fertilizer:

“This station (Maine Agricultural Experiment Station) was sent a sample (marine mud or harbor mud) by Fred Atwood of Winterport (Maine) the barrel of mud was received several weeks before being sampled and when it was opened it emitted a strong odor of ammonia.” 

This was a feature of bacterial reduction without oxygen – ammonia generation.
Sapropel when spread on fields soon had ultraviolent light quickly kill any exposed bacteria, when plowing into soils the organic residues that now fed oxygen requiring bacteria that grew below the surface away from UV light in the zone of rooted plants crops.  In deep sulfide-rich deposits, this benefit was realized only after a sulfuric acid release and in the agriculture records, it referencing the need to let it lay fallow as far back as the 1700s.  This reference from

From A Hint to the Farmers The American Museum, Volume III, #1 – On the Use of Mud as Manure, 1788, page 114 of this report is as follows: (In 200 years, some terms are not in common use today, my comments – T. Visel)

“Through my farm runs a little rivulet or brook, several parts of which are reservoirs or lodgments of mud (organic rich deposits – T. Visel).  I have made it a rule for some years, every summer I could find proper, as soon as my hay was combed off my meadows to clean these reservoirs, and spread the mud immediately on the ground.  The success was surprising – I venture to say, almost to double my crops for two or three years after.  I cannot get enough to dress my meadows all over, about once in three years: but, from what I have seen, that is often enough.  I have known many good farmers mix the mud when tolerably dry, with chalk lime, dung etc., and after turning it together a winter, lay it on their land and I allow this to be a good method but these additions are unnecessary upon meadows.  I should not, indeed think it prudent to throw it thus green (a reference to seasoning or lay fallow for a time  - T. Visel) on arable land (suitable for growing crops/farming).  The way I have hitherto (until now – T. Visel) made use of it, is carry it on by small low carts drawn by a single horse, and spreading it out of the cart with a scoop, and of this we can do a great deal in a day.” (From 1788)

Capstone Questions:

1)   Are fish dieoffs or Blue Crab Jubilees evidence of massive “natural” bacterial filter failures that release toxic sulfides?

In the historical fisheries literature, events described as fish kills are reported nearly always with the smell of hydrogen sulfide or the smell of “rotten eggs” nearby.  It is the reaction of sulfate bacteria that form hydrogen sulfide gas both in water, which turns black or contain aerosols that coastal residents call marsh “stink” usually in late summer when dissolved oxygen is low just after midnight.  It is at this time that oxygen-requiring bacteria turn to nitrate as a secondary source of oxygen.  When that is exhausted, sulfate metabolism becomes dominant with types of bacteria that do not need oxygen dissolved in seawater or nitrate but instead utilize sulfate, the most prevalent dissolved oxygen compound in seawater.  Oxygen-requiring bacteria secrete antibiotics to keep sulfur bacterial populations lower, but as oxygen bacteria die out, sulfate-reducing bacteria (SRB) that live on the organic matter, peat/sapropel, that collects in hot, low energy areas secrete substances that do the same thing; it kills them.  Once this happens, the positive ecosystems of bacterial oxygen nitrate pathways changes to a sulfate/ammonia pathway, deadly to fish and shellfish.  If long or severe enough, this filter reversal kills shellfish (blue crabs), leading to the creation of additional iron sulfide-rich and often “black water” with iron compounds.

Can this natural transition from oxygen to sulfate bacterial respiration in heat be created in laboratory conditions?  If so, how does iron influence the process?

2)    What can we learn from marine plants, such as Alterniflora patens and eelgrass, Zostera marina, that exist in marine peat.  In Europe, marsh peat at times was reduced to a liquid from termed “gyttja.”  How does gyttja formation compare to what is termed a sapropel?

Each plant – Alterniflora patens and eelgrass Zostera marina has adapted to the peat habitat (sapropel) in which it lives.  Plant phycology gives important clues to habitat succession in high heat by how each as adapted to the presence of sulfides a known plant toxin.  Both plants can live in a zone that can at times contain sapropel – Does eelgrass or Alterniflora developed special plant biology functions, enabling it to live in sulfide-rich yet low oxygen soils?  In heat, is there more of a chance or less of a chance of sapropel formation and can metal sulfides become an indicator for such marine soil processes?

3)   Oysters and blue crabs often share the same habitat profile with Spartina alterniflora and eelgrass Zostera marina.  Oysters in areas that form reefs or banks, alterniflora in or near these marshes and blue crabs in or near both.  The historical oyster and blue crab fisheries are often in the same bay or cove.  The historical literature references exist for sudden high heat oyster die offs, the same for Blue Crabs the “Blue Crab Jubilee.”  The same pattern exists for cold winter kill.  Marsh grass and submerged grass exist with the sulfur cycle but not always.  How do blue crabs and oysters survive the same sulfide events?  When eelgrass dies off can it be connected to a rise of sapropel – sulfide?  How do the habitat clocks for the blue crab and eelgrass compare over time?

All FFA-SAE experimental or non-experimental projects or papers require the appropriate SAE forms.  Please see your ASTE advisor for the appropriate pathway forms.

Introduction Spartina alterniflora – Sulfide Tolerance

Tom’s Creek was my blue crabbing spot in the 1960s.  I grew up watching Spartina alterniflora grow on the banks and mosquito ditches of Tom’s Creek, Madison, CT this creek had sufficient ebb freshwater flow to out what is described as an ebb channel – to Long Island Sound.  A barrier inlet Dowd’s to the east did not have the ebb and flow and filled a marsh and salt pond in what is today Hammonasset State Park.  Dowd’s Creek (inlet) has a history of opening and closure but Tom’s Creek to my knowledge has never completely “healed.”  (After Hurricane Sandy and Irene a large sand wave was deposited in front of Tom’s Creek causing the creek to exit far to the west and eroding the beach at the end of Pend Road – this sand bar (wave) was removed by a dredging project in 2014.

The Tom’s creek entrance was changed in the late 1960’s also by dredging to have the creek exit more to the north than along the beachfront – which was its natural exit in the 1960’s.  After this change, alterniflora quickly grew along the bank edges dredged banks and at other areas and trapped organic matter.  I noticed how alterniflora grew in areas that, for long periods of the day, were under water.  It was a tough grass as it doubled for twine in the capture of green crabs for tautog bait.  We didn’t need twine a smooth sheath of alterniflora did fine, a cracked mussel tied at the end was all that was needed to catch green crabs and their seemed plenty of green crabs to catch.  I never gave alterniflora much thought, that would change when I studied Oceanography in Florida (FIT Jensen Beach Campus) in the early 1970’s.  Here there was no alterniflora but Mangroves.  Again, here was a plant that lived between the land and sea – a plant in the middle.  Decades later I became to appreciate Spartina alterniflora more how it could survive in this habitat, how it could resist sulfides and sulfuric acids in marsh peat, how it could move oxygen form the air in its plant stems I once used as a bait string, how it could adapt to changing climate conditions and if it could help us learn more about sulfide toxicity impacting so many marshes and tidal creeks today.

Could it have evolved a different soil/root tissue mechanism to allow it to live with oxygen (low tide) and sulfate (high tide) and the different bacteria associated with each of them?  About three years ago a Sound School student, Joe, worked on a Capstone project about salt marsh die off in Tom’s Creek, Madison I found out about it after the project had started with Dr. Wade Elmer of the Connecticut Agricultural Experiment Station.  The paper is online titled “Sudden Vegetation Dieback in Atlantic and Gulf Coast Salt Marshes” – Plant Disease Vol. 97 No. 4, 2013.  One of the sites Tom’s Creek links the sulfur cycle by way of the peat chemistry that could be altered by extreme droughts (pg. 440).  How could temperature and droughts change make habitats “good” or “bad” for the blue crab and could similar sulfide events impact marsh grasses as well?

The Plant In The Middle Spartina alterniflora

One of the things I noticed going to the Florida Institute of Technology in 1973 was the Mangroves.  Here was a tree that lived at the edge, the shoreline with its roots on both land and in the water.  This did not compare at all to the salt marshes in Connecticut here along the Indian River lagoon was a plant that was a tree and lived in the water/marsh.  It was salt tolerant, could live in sulfate saturated soils (most of the trees I observed growing in freshwater bogs back home were dead or in the long process of decay) and had much of its root system exposed to air (no soil).  It was a plant between those plants that lived below the water submerged aquatic vegetation primarily eelgrass in our region and the peat that covered the surfaces of salt marshes – Spartina – salt hay.

Often termed smooth cord grass Spartina alterniflora was not harvested as salt hay as was Spartina patens termed salt meadow hay, which grew thick upon these coastal peat deposits.  Instead Alterniflora formed a border between submerged grasses (such as eelgrass) and the marsh plants living on the surface.  It was the first wave break to meet the incoming tides catching organics and slowing waters.  It also lived in the water covered by tides.  It did help form peat but lived in the humus without much root tissue between the cordgrass and other submerged plants such as sea lettuce, which had no roots.

Peat, which is formed by the collection of partially decomposed plant material in areas poorly drained or wet soils, often sustains a vegetation cover that consists of plants that obtain nourishment from the peat.  Subtidal peat, the collection of organic detritus both land and sea was the subtidal grasses – submerged aquatic vegetation “SAV” in the literature today.  In our region the species that has obtained the greatest attention has been eelgrass Zostera marina.  Between the subtidal peat (eelgrass meadows over time built a dense matt of root tissue) and the tidal peat exposed for a part of the tide cycle was perhaps the Mangrove equivalent Spartina alterniflora – is the plant “in the middle” so to speak.

Spartina Alterniflora – A Look Back

Growing up in Madison, CT, I can recall Spartina alterniflora as the high tide grass that held blue crabs.  In Tom’s Creek, Madison, CT, it grew on the banks of bends to about mid-tide and stood up like a straw and did not fall over like Spartina patens, thus providing a good spot for blue crabs to hold onto, especially if the flood current was strong.  Alterniflora became a place to search at high tide, and at times, blue crab would take a bottom bait and crawl over to it to enjoy a “free meal.”  Other times when the current was strong and drawn, bait would come off the creek bottom and swing to it.  Blue crabs riding along the grass line would latch on, and this grass was tough.  In fact, many times a clump would serve as an anchor while drifting in a small Brockway dingy.  But it seemed to be a hollow tube, which allowed air to come into contact with the plant base and help keep oxygen around its roots.  It grew between the eelgrass and marsh peat surface plants, the first line of plants that held and helped create marsh peat.  It was a living shoreline that, by its roots, held exposed peat, protecting it from waves and strong currents.  When you walked on it, you often sank in soft ooze until you hit root-dense peat below.  You could not walk over it, two or three steps, and that was it; one or both feet would be held and become stuck. 

It was a different story for the marsh surface.  Here the peat was much firmer except at dug mosquito control ditches.  Here would be a band of Alterniflora often lining both sides of them and soft sections that made crossing these ditches difficult.  In my early blue crabbing experiences, I had no idea of the complex chemical-oxygen processes underway that allowed these plants to live in sulfide habitats but most terrestrial plants are considered toxic to or, at best, unfriendly.  Like the first colonial farms that cut salt hay, I marveled at its ability to withstand extreme summer temperatures (on hot August days, pools of water easily reached 100oF) and covered in ice with sub-zero temperatures.  For Alterniflora, life was even more difficult; it was submerged and exposed twice a day.  To fully understand Alterniflora, you first need to understand the chemistry in which it lives, shared by the same habitats of the blue crab.  It is the peat, which contains elements of the nitrogen, sulfur and carbon cycles connected to oxygen and iron that governs much of the marine life in salt marshes.  It is in many instances that same chemistry which impacts the Blue Crab.  The processes greatly change with temperature and provide the foundation of the concern about a warming planet and the rebuilding of the sulfur cycle – my view, Tim Visel.


Marsh Peat and Sapropel

The marshes to the first European settlers provided instant animal forage and bedding.  Coastal farmers soon realized that this marine compost once exposed to air oxygen was a valuable soil nutrient (food) source for oxygen bacteria or that helped plants such as marsh hay grow.  The oxygen exposed muds were usually brown (valuable), while those created in low oxygen environments were black or even blue and held little economic benefit.  The need to feed large populations on limited land (England for example) created the need to manage marshes to control water, which is associated with peat formation across the globe.  Wet and often anaerobic peat has less root tissue mass it is soft and unsuitable for agriculture (excluding rice).  This is also reflected in the early Colonial tax roles – wetlands were without much value – because they could not contribute immediately to agriculture.  In fact at times wetlands in the historical literature are linked to disease (mosquito vectored disease) and bad smells (once thought to be a vector of disease itself).  Draining them became an accepted agriculture practice and some of the first mosquito disease efforts included the same practices, draining the water or restricting the presence of water, tide gates “sluices” or dikes to reduce or eliminate mosquito habitat.  Efforts to drain marshes have been and continue to be a part of coastal life along much of our shores.  Most likely the community that has the best case history of the first tide controlled marshes for salt hay is Guilford Connecticut.  At one time Guilford’s common lands included sections of salt marsh hay that was cut and sold to support its public schools.  Up until the 1960’s the lower sections of the East River marshes were still called “School Meadow” (Frank Dolan – personal communication, T. Visel, 1980’s Army Corps of Engineers map dated 1957) Guilford, Connecticut location of sluice gate at Guilford, CT.  Connecticut Conservation Association Newsletter, June 1968 – Guilford Madison Marsh Complete – “School Meadow 930 Acre Tract Held by the Town of Guilford (so named because in earlier days, hay was used for the teacher’s salary).”

The sluice gate for salt marsh harvests in Guilford is still operating although the hay harvest no longer happens.  Other marshes were also soft – to soft to support horses and hay harvests and these drained so the peat could firm up but this could take years.  Inland wetlands continued to have low tax role value until converted into cranberry bogs (which also was connected to water elimination/retention).  At one time, central Connecticut was a significant cranberry producer from the 1880’s to the 1920’s centered around Killingworth, CT.   Controlling water allowed air with oxygen to penetrate the peat and allow bacteria that needed oxygen to produce nitrate and allow roots to live and not be killed by sulfur/sulfide root rot.  Did early salt hay and cranberry produces realize that water was a proxy to a bacterial war between oxygen and sulfur species in the peat – most likely no but they could see the different (value of crops) by controlling the water and by doing so – favored oxygen bacteria.  The battle between oxygen and sulfur is as old as time itself.  In time the value of marine mud (sapropel) would be used to nourish peat in oxygen and on terrestrial fields.  However, sealed mud that had little access to oxygen purged sulfuric acid before its plant growth potential could be realized.

The bacterial war is based upon sulfur and oxygen chemistry – heat/drought tended to lower water tables but it long enough allowed sulfur bacteria to live close to the surface killing peat root tissue.  Marshes became softer and black; they smelled bad late at night.  Farmers noticed under these conditions marshes could even sink.  In cold and rain, marshes were oxygen limited, and much the same results lower marshes converted back to sapropel on iron sulfide rich ooze.  Strong storms overtapped the marsh and washed this sapropel away, lowering the peat mass even further. 

Water became the deciding factor in hay crops from salt marsh peat – to wet and soil pore filled with water, rotted roots, too little and the oxygen could form sulfuric acid also impacting roots.

But deep below the peat surface a bacterial war raged, unseen to colonial farmers but extremely important.  Oysters could do little when the sulfur cycle arrived – in high heat they starred and then died.  Spartina alterniflora could hold out longer it lived between the sulfide ooze and acid peat.  But if sulfides get to high it dies back as well.  The Blue Crab however could move, either to the surface or even out of the water itself – a jubilee.

In the sulfur wars of long ago the blue crab came to realize that fleeing sulfate reduction give it a better chance to live then fighting it, nature it seems gave the blue crab an option that oysters and marsh plants could not do when it can – run from sulfide which is toxic outright to fish and shellfish.  We can see the damage to plants and benthic organisms when sulfides occur – oysters and estuarine plants die – blue crabs flee as they did from the Housatonic River after a hot water rain surge in following tropical storm Lee in September, 2011.  Spartina alterniflora cannot flee that is why its ability to cope with high sulfides deserves further study (my view, Tim Visel).



APPENDIX #1

The Importance of Oxygen Diffusion Rates and Chemical Oxygen Demands in Influencing Vascular Plant Zonation Patterns on the Salt Marsh

By Eric S. Yuhas

From Selected Investigations on New England Salt Marshes
Project Oceanology
Pfizer-Marine Research Program
1983

Introduction

The Project Oceanology Pfizer Marine Research Program is a privately and municipally funded program that involves twelve high school students each year.  Begun as an outgrowth of the now defunct National Science Foundation Student Scientist Training Program, our course affords students the rare opportunity to do actual scientific research at a comparatively young age.  The primary goals of the program are to develop the skills necessary to conduct a primary literature search, to enhance student’s analytical and scientific writing skills, to create an intellectually stimulating environment that gives gifted and/or talented students a much needed outlet, and to further our knowledge of the marine environment.
   This year’s study centers around the interaction between the biological, physical, geological, and chemical interactions of salt marshes.  Led by staff members John A. Scillieri, Jr. and David R. Scott, the students have conducted a three phase research schedule.  The first phase, a primary literature search and research question development period, was conducted in the spring of 1983.  The second, active research portion of the program was undertaken in the summer of 1983.  The research has concluded this fall with a computer assisted analysis and the production of a written research report.
   The high caliber of the student research is evident upon examination of this document.  While several of our findings are of considerable interest to the scientific community, all team members have greatly expanded both their personal knowledge and their own horizons.

PROJECT OCEANOLOGY
1983 PFIZER MARINE RESEARCH TEAM MEMBERS

STUDENTS:

Jennie Lee Aitkenhead            Diane Marie Bowley
   Fitch Senior High               New London High School
                        
Jill I. Cairns                  Frank Canneto
   Waterford High School            Ledyard High School   

David Nelson Greineder            Stephen Alan Habbe
Waterford High School            Ledyard High School

Jennifer McGowan               Todd G. Milne
   Williams School               East Lyme High School   

Paige Andree Nardone            John Edgar Reed
   Stonington High School            New London High School

Eric Yuhas
   Waterford High School

STAFF:

John A. Scillieri Jr.
David R. Scott
 
TABLE OF CONTENTS


PAGE                STUDY

1-32   The Effects of Aeration And Salinity On Spartina Alterniflora, Spartina Patens, and Salicornia Europea

33-60   The Relative Importance Of Environmental And Genetic Factors In The Determination Of Short And Tall Form Spartina Alterniflora Growth Forms

61-84   The Effects Of Fertilizer Enrichment And Clipping On The Growth And Survival Rate Of Transplanted Spartina Alterniflora

85-103   The Effects Of Mycelium On Root Growth And Plant Height On Various Salt Marsh Plants

104-115   Effects Of Mycelium And Oxygen On Productivity

116-132   The Importance Of Oxygen Diffusion Rates And Chemical Oxygen Demands In Influencing Vascular Plant Zonation Patterns On The Salt Marsh

133-153   The Examination Of Cyanophyta Zonation On A Connecticut Salt Marsh

154-167   Feeding Behavior And Growth Of Fundulus

168-183   The Effects Of Population Densities Upon Modiolus Demissus And Melampus Bidentatus

184-196   Factors That Affect The Distribution Of Uca And Their Effect On The Sediment


The Importance of Oxygen Diffusion Rates and Chemical Oxygen Demands in Influencing Vascular Plant Zonation Patterns on the Salt Marsh

By Eric S. Yuhas


Abstract

   This study was designed to investigate the importance of oxygen diffusion rates and chemical oxygen demands in influencing the zonation of vascular salt marsh plants.  Oxygen diffusion rates and chemical oxygen demands were examined in the Spartina alterniflora, short and tall form, Spartina patens, and Juncus gerardi zones of a salt marsh in the lower Poquonnock River estuary on Groton, Connecticut.  Oxygen diffusion rates were found to be significantly higher in the tall Spartina alterniflora zone than in all the other zones.  Chemical oxygen demand was found to be higher in the tall Spartina alterniflora zone, but in this zone, the chemical oxygen demand was found to be a lesser percent of the available oxygen than in all the other zones.  The zonation of the height forms of Spartina alterniflora was found to be influenced by oxygen diffusion rates, and available oxygen, which is affected by chemical oxygen demand.  The zonation of Spartina patens and Juncus gerardi was found not to be influenced by oxygen diffusion rates, chemical oxygen demand, or available oxygen. 


Conclusions

Oxygen diffusion rates were found to have an influence on the zonation of Spartina alterniflora height gradients.  Tall Spartina alterniflora occurred in places with the highest ODRs on the marsh while short Spartina alterniflora was found in places with significantly lower ODRs.
The zonation between Spartina patens and Juncus gerardi did not appear to be affected by ODRs because the ODRs were not significantly different between these zones.
The height forms of Spartina alterniflora may be zonated according to available oxygen, which is influenced by COD.  The tall form had a higher mean available oxygen than the short form.
   The Spartina patens and Juncus gerardi zones are not influenced by COD because no great differences in COD or available oxygen were seen between these zones.
   If ODRs and CODs influence the respiration of vascular marsh plants, then they must also influence the productivity of these plants.  Spartina alterniflora is most productive in its tall form, tidally subsidized and full of the aerating holes of burrowing organisms, in which it respires more due to increased available oxygen and oxygen diffusion rates.  Short Spartina alterniflora could be artificially aerated by excavation.  Theoretically, this would increase the productivity of the plant, and increase the salt marsh’s capacity for productivity.   

A SPECIAL NOTE OF THANKS
The 1983 Project Oceanology Pfizer Marine Research Program Team wishes to extend thanks to:

Donna Johnson of Marine Sciences Institute for her technical help, spirit, and advice,

Dr. Barbara Walsh of Marine Sciences Institute for her technical assistance and patient explanations of computer software,

Dr. Scott Warren of Connecticut College for his assistance alnd loan of a Jensen Oxygen Diffusion Ratemeter,

Dr. Robert DeSanto for his technical expertise and the use of a florimeter,

Dr. Howard M. Weiss of Project Oceanology for his generous use of time and his help with the computer,

Dr. William Zeronsa of Pfizer for his help with deionized water,

Dr. John Buck of the University of Connecticut, Noank Marine Biology Lab for his assistance,

Mr. Bo Kacharowski of Pfizer for his help in obtaining mycelium,

Mr. John Wilkenson of the City of Groton Pollution Abatement Plant for his assistance in obtaining sewage sludge,

The entire Project Oceanology Staff for their help all summer,

The parents of all team members for their cooperation and sincere interest in their young adults,

and finally, to the Pfizer Corporation and the Sea Grant Program for their funding without which this program would not be possible.





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