IMEP # 135 Part 2 The !920's Shows Marine Soil Reverse

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IMEP #135 Part 2: The 1920's Shows Marine Soil Reverse
Alkaline Maerl or Acid Sapropel Composts
Signals Habitat Change
"Understanding Science Through History"
The CEC of Marine Soils and Habitat Succession
Viewpoint of Tim Visel – No other Agency or Organization
Readers should review IMEP #135 Part 1 posted on June 11, 2024
Tim Visel Retired from The Sound School – June 30, 2022
January Review 2022
This is a delayed report

Introduction

What Makes a Good Clam Soil
Methane Increases After Flooding – Reflects Change in Soil Bacteria, The Mud Mounds of Europe

Methanogens are kept to low levels by sulfate-reducing bacteria, which consume their food before they can access it.  As seawater contains an unlimited supply of sulfate (SO4), it is "non-limiting" to sulfate bacteria.  Methane production is limited by the presence of sulfate, which is buffered by nitrate NO3 or iron Oxide Fe304 Fe (III).  That is why removing nitrate, or other oxygen compounds for example, also removes a potential oxygen source.  I mentioned this nitrate – (oxygen) source during the nitrogen TMDL process for Long Island Sound.  This bacterial nitrogen response, however, was not often included in nitrogen source resource reports.  The influence of soil bacteria to shed nitrogen compounds was also often not included.  Once methane is produced in the low or no oxygen zone, it can be oxidized to CO2 and is directly related to oxygen availability in the soil.  For example, mound builders in ancient Denmark piled up mud, lifting it from anaerobic horizons into a horizon dominated by oxygen so important nitrogen bacteria could live, establish nitrogen ionic pathways into plant root tissue (i.e., the growth of plants – agriculture).  Once these mounds were raised, the soil could sustain oxygen-requiring bacteria and then assist nutrient ions crossing (nitrate) root tissue.  The use of mud (water soils) in Denmark is an old practice and found in European agriculture history.  Bringing mud above to air allows farm soil bacteria to live and improve crop yields is a common response to flooded soils.

In Recent Marine Sediments edited by Parker D. Trask of the U.S. Geological Survey, Washington, DC (1955), Walter Hantzschel – paper on Tidal Deposits (German translation Wattenschlick) in 1938 describes the use of tidal muds to support agriculture. 

Page 204 of Recent Marine Sediments contains the following:

"The great fertility of tidal mud also makes it possible to use it extensively for improving poor soils, especially boggy soils.  The Dutch people say: "The faster you mud, the sooner you are rich."  Great increases in crop yield have been obtained by the agricultural use of this mud; in fact, in eastern Friesland 30 to 40 percent greater returns have been obtained, and the mud there is taken from the harbor of Emden and the navigable water of the lower Ems."

Eelgrass is a similar peat soil builder and has similar peat soil chemistry.  As long as it was cool and oxygen sufficient eelgrass itself could become a mound builder.  This is mentioned numerous times in the shellfish historical literature – as eelgrass grew in similar marine soils as those with clams.  By its structure, eelgrass collects organic matter and can as part of its life cycle host small bay scallops.  This observation was often made when seawater was cold and able to hold greater amounts of dissolved oxygen.  In times of hot seawater and low dissolved oxygen observations can change from habitat chemistry.  A large influence upon benthic chemistry was the climate but most researchers omitted chemistry but focused upon biology and seafood abundance (catches).

It is here perhaps we can see those (including Nelson Marshall) researchers who observed "bay" scallop catches and those that participated in them.  When you examine the historical bay scallop fisheries literature you immediately see a strong focus upon biology – and very little describing habitats or gear.  In the report by James S. Gutsell – "Natural History of the Bay Scallop" – United States Bureau of Fisheries (A Thesis submitted to Cornell University that was published Nov. 13, 1929) his job title then was Associate Aquatic Biologist.  Scallop crops soared in New England after 1922 following a series of severe winters.  On page 614 Gutsell mentions this shift and the loss of seed from the cold, (frequently mentioned in the historical scallop literature during times of abundance).

"Sometimes in severely cold weather, as that which occurred late in December 1925, there is considerable mortality among scallops in very shallow water or on flats which are exposed or nearly exposed at low water or on flats which are exposed or nearly exposed at low water."

Gutsell also mentions the surge of bay scallop catches after 1921, comparing the Massachusetts bay scallop catch of 1880 of 111,000 lbs (meats, not bushels) to 1,235,304 lbs for the combined 1928 and 1929 harvest years.  (Rhode Island state officials reported that in 1924 following two bitter winters a catch that as a low estimate exceeded 300,000 bushels or 1.8 million pounds).

Although Gutsell makes significant contributions to the biology of the bay scallop especially its response to low salinity and starfish predation, and catch, habitat information and gear type is only a half a page.  The scallop literature has few studies that focus upon the fishery about the gear and locations of commercial scallop grounds.  The fisheries literature was at that time was dominated by biologists, and mention of the commercial industry usually included regulations or catch limitations rather than climate and habitat conditions that made many of these high catches possible.  This is especially true for the bay scallop as its catch is made after adults spawn – there is little reproductive capacity lost as these adults perish before a second spawning event.  David Belding directly comments upon this aspect (about man not being able to overfish this species).  David Belding explains how bay scallops are not overfished from regulations (lack) or catch levels.

A report upon The Scallop Fishery of Massachusetts David Lawrence Belding 1910, "The Scallop Fishery" on pg 72 is found this segment,

"So while the scallop had declined in certain localities, and the decline has been hastened by unwise capture of the "seed" scallop, the main decline of the fishery cannot be attributed to wholesale overfishing, as it is impossible to overfish if only the old scallop (over one year old) are taken."

The sulfide impacts of heat and bacterial sulfate metabolism was not on the biologists radar – as despite high pollution (organic loading) rivers did have oxygen levels that prevented black water.  It was cold and cold water naturally holds more dissolved oxygen.  The largest management concern often was moving seed scallops from areas subject to freezing.  Storms would cast millions of seed scallops on beaches and in the historical records mention movements of "shallow" seed to deeper water.  These references indicate that shallows bays and coves were more of a larval and seed trap rather than preferred habitat types.  Storms could drive seed into the shallows by the millions.

In fact, when you examine temperature and energy levels you can see how storms could cultivate and move shallow marine soils.  This habitat/shellfish impact is quite noticeable with the rise of Rhode Island hard clam sets, beginning with 1925, as the cold could put more oxygen into organic heavy content soils.  Little connection was made that quahogs do better in cultivated soils free of sulfide while oyster sets failed with the increasing cold and subtidal soil chemistry change.  This quahog sets after 1938 increased as Rhode Island quahog catches soared.  A series of storms and dredge vessels cultivated bottom soils – freeing them or organics similar to hand rakers in shallow waters.  Large catches of the Rhode Island quahog soon followed.

Soil cultivation either man or by storms tends to release sulfides, increased oxygen exchange in pore waters, and the movement of ions including calcium – important to shell formation.  In sulfide soils, and those with sulfuric acid shells were often thin and weak – and one of the many soil renewal factors now associated with storm events.  The historical shellfish records were not focused upon soil science, but on catch and habitat stability.  Storms were seen to be destructive and seafood wasted thrown high on flats or bars to freeze or consumed by other predators created a long ago bias that comes into policies today.  Storms were seen to be negative in terms of shellfish as soil chemistry reviews or habitat monitoring efforts did not exist.  We have the records of great clam sets after storms and references to new soil mentioned as "new sand."  Clarence Cottam a noted eelgrass researcher of the past century, even himself mentions "new sand" and eelgrass.

In a 1947 paper now part of the Transactions of the North American Wildlife Conference Vol 2, page 394 contains this section pertaining to the construction of The Cape Cod Canal.  (From Cottam and Addy Present Eelgrass Conditions A Long The Atlantic Seaboard of North America):

"This dike was built with sand pumped from the bottom of Buzzards Bay: work on this dike was beginning June 1936 and finished February 1937.  The dike thus consists of "new sand" that is sand which hasn't been in shallow water for many years, probably in historic times, yet on both the north and sound sides of this dike, are healthy stands of eelgrass stands, which have among the best I saw during the entire summer (Stevens 1946).

This account clearly describes the beneficial aspect of cultivated or "storm washed" soils.  It is natural during periods described as "stagnant" or foul that soils obtain organic litter of dead plant tissue.  It is these composting soils (soils without disturbance) that fungus and slime molds exist and at times thrive. 

Current public policies for non-disturbance and absence of CEC soil measures are in opposition to marine soil pH, pore and charged ion (CEC) science.  The relationship to soil pore exchange and temperature dissolved oxygen exchange is perhaps the largest factor to eelgrass health and why it suffers high heat low energy cycle dieoffs.  Soils that are stagnant, hot and have high organic content are able to produce toxic sulfides.  Bay scallops are extremely sensitive to sulfides.  We need to include soil science in shellfisheries management research, especially for the soil pH - my view, Tim Visel.

Aquaculture Soils for Bay Scallops

A better or preferred habitat for scallops is soils that are basic or alkaline from an algae species classified as coralline Rhodophyta.  Scallops which set on this algae that secrete calcium carbonate and in time produces a carbonate rich sticky paste deposit called Maerl.  This coralline algae which is suspected a source of signal compounds when torn by storms (bleeding grass syndrome).  This possibly signals to scallops the location of this alkaline marine soil algal compost.  This alkaline paste substance appears to reverse over time with an acidic marine compost sapropel.  Bay scallop larvae setting on a low pH bottom can survive for only a few seconds, but in Maerl beds consists of an algal paste rich in carbonates (calcium) and as such used in some countries to offset acid terrestrial soils.  Steneck (1986) mentions that crustose corralines are non-articulated calcareous red algae commonly grow prostrate on hard substrate and belong to a broad group of red algae termed corallines.  It is a cold-water alkaline compost that has been found North Sea to be up to 10 meters thick.  (The Ecology of Corraline Algal Crusts, 1986.  Annual Review of Ecology and Systematics Vol 17, pages 273-303).
 
Agardhiella red weed is also mentioned (Agardhiella subulata) as a scallop habitat and a great description can be found on pg. 52 "Seaweeds of Long Island Sound" by Margaret Stewart Van Patten 2006 Connecticut Sea Grant College Program.

Agardhiella subulate – also known as red wooly grass, Agardh's Red Weed,

"This is one of the most common red algae in Long Island Sound.  It is easily confused with Gracilaria.  Agardhiella contains antiviral compounds currently understudy for medicinal use.  A. subulata is sometimes habitat for young scallops."

Agardhiella subulata or "Agardh's red weed has a long history with scallops.  In a book titled "A Popular History Of British Sea-weeds" by David Landsborough (1857) is found this section, pg. 189:

"It is from one to three inches in height color a fine rosy – red substances soft, gelatincus, adhering well to paper.  It was found by as while dredging in Lamlash loch, growing on living specimens of Pectin Opecularis.  (Our boatman were surprised at the avidity with which we grasped at whatever was growing upon the scallop, regarding with surprise." From a 1833 discovery of Callithamnian – later this is added –
"I am sorry that the scallops which yielded such rich crops of seaweeds and zoophytes have disappeared from the bay. The fisherman finding that they made excellent bait had in their greed, I suppose, exhausted the bed" and on page four – referencing another corraline red algal species – Griffithsia corallina which includes more habitat descriptions of scallops,

I have dredged it in Lamlash Bay, where it is found on the persecuted Pecten opecularis quite willing was I to return the scallops to the sea after stripping them of their outer growth.  This, instead of being robbery, was mercy, for I am sure these seaweeds and zosphytes must have been a sad encumbrance to them in those merry evolutions in which the scallops delight to indulge, when they skim through the water in mystic dance.  The scallops dance most merely when I first saw some of them at their gambols in a tide pool, I thought they were young fishes, but I found that they were the young of Pectan opecularis.  By opening and suddenly shutting their valves, they skim rapidly along several yards when they repeat the operation." (pg. 195)

On page 271 another red algae is mentioned as associated with scallop habitat, Chrysimenia, Clavellosa D. agardh:

"We have got it on scallops dredged from deep water in Lamlash Bay.  It is found on all British shores."

Although eelgrass was established along the English coast and studied for its ability to collect organic matter it is not mentioned here.

During the period 1880-1920 eelgrass coverage reached a southern New England cyclical peak with its peak coverage between 1905 and 1915.  George Nichols (1920) an astute plant biologist has left us a huge reference for us to review coastal vegetation during this time.  It is important not only for his observations, extensive literature source and perspective but is free of the regulatory/conservation bias so apparent in later articles about marine vegetative (especially eelgrass) my view.  These observations point to a transition to a sulfide rich compost in times of heat.  The Vegetation Of Connecticut George E. Nichols Bulletin of The Torrey Botanical Club (1920), has this segment:

"The most distinctive plant of muddy bottoms along the sea coast is the eelgrass.  As already noted this also grows on sandy bottoms but it never attains where growing on muddy bottoms.  So prolifically does it thrive in the shallow waters of protected harbors and coves that at low tide large areas of muddy bottoms here will be almost completely hidden by its clusters of long slender leaves." (pg. 523)

In New England the 1880-1920 period was a time of "great heat," mostly mild winters and very few storms allowed waters to be clear and greatly reduced turbidity.  Eelgrass helped keep waters clear, by trapping and holding particles, silt, bacteria and bits of organic matter including leaves ground up bark and terrestrial grasses.  The absence of strong storms, mild winters and at times extremely hot summers allowed eelgrass to dominate sheltered bays and coves and time even deep coastal waters.  This also occurred in as inlets and bay openings tended to close from few storms.  This helped the formation of thick blankets of organic ooze in heat.  Eelgrass growths thick and root filled formed a type of subtidal peat.  In heat with little oxygen this peat can become acidic.  The source of the acidity was bacterial produced sulfide which transitioned into sulfuric acid.

Florida's research of sapropel/peat found that draining peat of water caused sulfides to be converted to sulfuric acid.  This resulted in acid sulfate soils.  This was not new to agriculture researchers.  In a 1926 report in the University of Florida Bulletin 184, Agriculture Experiment Station conducted by R.V. Allison (Stimulation of Plant Response on the Row Peat Soils of the Florida Everglades) -contains these sections:

Pg. 37
"The accumulation of plant residues under conditions of excessive moisture usually constitutes peat soils.  Under such conditions the anaerobicity, or lack of air, largely prevents the decomposition of the freshly fallen material beyond a certain stage, hence the accumulation of such organic deposits from century to century." 

And further –

"Thus if the peat is deposited upon sand of heavy clay out of contact with lime or lime containing waters, it is almost certain to be acid in character."

Four decades later two Connecticut Agricultural Experiment Station researchers David H. Hill and Arthur E. Shearian would write bulletin 709 "Tidal Marshes of Connecticut and Rhode Island" which mentions the same peat – acid conditions,

"In the estuarine marshes along the major rivers, the sediments are more acid, with pH ranging from 4.3 to 6.6.  This acid pH corresponds to that in fresh-water marshes.  The greater hydrogen ion concentration comes from organic acids produced by decaying plants in an environment deficient in oxygen." 

And further –

"The dramatic increase in acidity after draining and drying is caused by oxidation of sulfur, a process called sulfur acidity.  The stage for oxidation was set earlier in a wet, oxygen poor environment.  Here, anaerobic sulfur – reducing bacteria extract sulfate from sea water, use it, and then concentrate it in sediments.  Thus the sulfate of sea water is transformed biologically and chemically to black hydrous iron sulfate and hydrogen sulfide gas.  As marshes are drained or samples dried, oxygen permeates the sediment and sulfide is converted chemically to sulfate, some sulfate combines with hydrogen and produces sulfuric acid and low pH."

What is missing is the pre-state of marsh peat, the creation of organic sulfide rich sapropels (a few tablespoons of sapropel exposed to air at room temperature will soon fill a small room with strong sulfide smells).

This sulfide rich compost is oxygenated by cold water containing oxygen being driven into it – largely by storms.  This has the same impact and a flush or event of sulfuric acid happens when oxidation is introduced similar to core aeration of terrestrial peat (lawns) or killing organisms unable to withstand acid waters.

These events are magnified by a long period of heat and few storms – such as the 1880 to 1920 period in New England.  In colder times red algae was abundant, in heat eelgrass.

This alkaline compost is rich in calcium carbonate and is harvested overseas as a natural organic fertilizer for centuries.  Maerl beds have been found to be significant habits of the Queen Scallop Aequipectin opercularis (see Kamenos et al., 2004 Nursery – Area Function Of Maerl Grounds For Juvenile Queen Scallops Aequipecten opercularis And Other Invertebrates).

Nelson Marshall in his research into the Niantic River Bay Scallop fishery may have given as an important research area to pursue and one that reflects capture fisheries comments on habitat, (a rare mention of harvest perspectives – T. Visel) is found in this quote:

"In this connection it noteworthy that fisherman of the Niantic River refer to such algae as scallop grass."

And further –

"It was evident that the small branching algae, observed to be very abundant throughout the river, were heavily laden with attached scallops."

When the climate changed in the early 1920's eelgrass sapropel peat now was subjected to some bitter cold and storms.  Wave energy now cultivated these meadows bringing sulfidic mud (sapropel) to the surface generating sulfuric acid – long a problem to terrestrial farmers that harvested "marine mud" from deep deposits and once spread on fields as a manure.  This harbor or marine mud caused sulfuric acids that a times damaged plant crops and negated for a time any soil carbon/nitrogen benefits.  After this became identified New England Agriculture Experiment Stations (including the nation's first Agriculture Experiment Station in New Haven, CT) who advised farmers using sapropel (rotting organic matter without oxygen) to cut in lime or bivalve shell to offset this "harmful acidity."  (See Connecticut Agriculture Experiment Station Bulletin 194, July 1917 Manure from The Sea).

Farmers from New Jersey to Maine were advised that harbor mud needed lime or shells of bivalves to reduce acid levels.  This change in shallow water indicates that scallops prefer deeper areas with more current and less sapropel.  The bay aspect happens when strong storms sweep small seed scallops into them.  A strong storm would also cultivate shallow marine soils reducing eelgrass.

Once that happened the sulfuric acid impact was negated.  However, this sulfide/sulfuric acid in eelgrass peat, weakened the plants and dissolved the peat tissue – allowing a series of colder storm filled winters to rip up these plants and caused them in high heat to succumb to fungal (mold) infections a symptom of sulfide root rot. 

As these coastal storms increased in intensity and frequency the fine clays and silt the mineral constituents of soils made the water turbid blocking light to eelgrass deep water beds (meadows) furthering weakening eelgrass meadows.  Storm intensity increased and waters cooled (allowing oxygen saturation rates to rise) bacterial populations decreased shutting off ammonium as composting lessened.  Eelgrass meadows are often observed to "rise" during periods of heat and little storm activity (John Hammond, personal communication T. Visel 1980s) (Belding 1930) now sunk as peat washed free of organic matter leaving roots exposed or was washed away. 

This decline in eelgrass was a combination of sulfide/sulfuric acid root failure and intense fungus (slime mold) growth in summers.  As sapropel itself was mixed or washed away by powerful storms eelgrass habitat cover declined in deep water(s).  While then increased as marine soil cultivated increased in the shallows (post 1938 Hurricane) increasing the turbidity and restricting light access in deep waters (salt marsh decay).  Eelgrass meadows which strengthened in the four decade of heat and few storms (1880-1920) naturally declined into habitats more favorable for shellfish.  (Often displacing other aquatic plant species) in the 1940 to 1970 period as eelgrass coverage expanded in areas 2 to 10 feet – in the same habitats that sustained soft shell clams, bay scallops and the hard shell clam.  This habitat reversal frequently suffocated benthic shellfish and many Massachusetts reports detail eelgrass damage to shellfish in many coves and rivers.

When eelgrass died out in Niantic River, it soon became colder and storm filled.  Scallop populations increased.  This is opposite most of the bay scallop research that promotes non-disturbance – as this in time creates "dead bottoms" or dead soils – those that contain few oxygen requiring organisms.  It is the absence of sulfide and acids that are so toxic to shellfish spat.  Landing on sapropel spat is killed in just a few seconds.  (See Calabrese (1972).

When this temperature and energy is applied to an alkaline pH soil (corraline red or cultivated sand shell hash) the increases in bay scallops in cold and connection to storms is clearly seen in the New England catch reports. 

As the storms intensified in the 1930s with the New England Hurricane of 1938 bay scallops landings actually increased as eelgrass declined.  The eelgrass decline was devastating to waterfowl especially Brant who had come to favor eelgrass as it grew dense in the great heat – 1880 to 1920 now starved by the tens of thousands as they watched their forage ripped up and cast out to sea.  But the bay scallop crops during this cold and stormy period all increased in fact they soared.  The catches in the Poquonnock River in the 1950's and 1960's had become so large waiting lines formed for permits (personal communication Stephen Jones, Ken Holloway, Groton Shellfish Commission – personal communications Tim Visel, 1986).

When the energy stopped and waters temperatures stabilized eelgrass quickly moved into cultivated soils as bay scallops now declined.  Contrary to what is in the printed reports about eelgrass and bay scallops CT catches were highest when storms were numerous and waters cool.  (The connection to climate conditions is now difficult to dismiss - my view Tim Visel).  The year of 1955 would bring two hurricanes and a disastrous flood to our Long Island Sound coast – but the Connecticut bay scallop crop that year would reach new total harvest records.  (A gear restriction had however eliminated the deep-water dredge fishery).

As bay scallop catches declined eelgrass coverage increased just as they did a half century before – bringing eelgrass and shellfish harvesters into conflict – once again as habitat succession changed soil conditions against shellfish including killing oysters often speeded by growths of eelgrass.  (See Chatham Quahog Fishers Final Stand Against Eelgrass Blue Crab Forum™ posted on the Blue Crab Forum™, Oct 9, 2014).  Canadian officials conducted studies on how to control eelgrass in the 1950s.  But concerns about eelgrass regrowth and negative impacts to shellfish population were voiced in the 1930's from references that occurred in the 1900s.  Clarence Cottam, one of the first eelgrass researchers, was informed about this in 1947 that eelgrass would choke the bottom and anything living in it.  In one of the first papers about eelgrass by Dr. Cottam contained a question an answer period in reference to eelgrass returning to New England shores.

After presentation of a paper by Cottam and Addy (1947) Mr. Bruce S. Wright (New Brunswick, Canada) comments "What is the reaction of the fishermen on the coast to the appearance of eelgrass.  I know in the Maritimes they deliberately dig it out when it comes back; they don't want it back." 

This period is when the NAO turned negative and colder temperatures proceeded past the 1920's into the stormed filled 1950's.  In a review of the start of the Niantic River fishery Nelson Marshall's work (1947) points to a direct climate link.  The scallop dredge was the gear of choice in 15 to 25 feet of water.  Strong storms could however sweep immense quantities of small scallops into shallow waters – into the range of dip nets – spotters.  As long as it remained cold these scallops could mature into a shallow water fishery – and years of strong storms are associated with large Niantic River crops of "bay" scallops without eelgrass (An Abundance Of Bay Scallops In The Absence Of Eelgrass Ecology, Vol. 28, #2, July 1947, p. 231-322).  Without strong storms scallops persist in deeper offshore waters but because of gear restrictions this fishery no longer happens.  Strong storms swept seed into bays and coves, such as Nelson reported in 1947 in the 1930s.  Bay scallops thrive in the coldest of times, they prefer cooler water with nitrate fed algae.  A sudden shift to heat can kill bay scallops.  The 1950's saw the climate cycle NAO in a negative phase and some of the coldest winters in a century.

This can happen in shallow water subject to quickest warming.  This is an example of rapid habitat compression, what was once a suitable habitat quickly becomes unsuitable or deadly.  In 1917 a winter flounder dieoff was reported in Moriches Bay when circulation was restricted during a heat wave (COPEIA New York, March 19, 1918 #55 – An Abnormal Winter Flounder And Others J. T. Nichols) trapped in part of Moriches Bay.  There hundreds of small winter flounder perished during a heat wave between July 19 and August 4, 1917.

Several references exist in the herring (alewife) historical fisheries literature about restoring tidal flows to prevent black water or stagnant water killing fish.  Warmer water and sand bars could close off alewife runs.  David Belding of Massachusetts described these runs as those "separated from the salt water by a narrow sand beach though which there is a shifting natural opening or an artificial channel" pg. 12 – A Report Upon The Fisheries of Massachusetts 1921.

Restricting circulation could warm the water, and these small salt ponds could turn black and smell of sulfides, so they were unblocked to prevent the loss of fisheries.  It is now suspected, in high heat, a potential alewife "block" from the presence of sulfide.

A recent massive bay scallop kill that happened in New York's Peconic Bay is thought to be a type of black water fish kill.  High heat, reducing oxygen levels, and organic matter support iron sulfides toxic to fish and shellfish.  During the summer of 2019 adult bay scallops perished in warm waters of Peconic Bay.  After several years of cooler springs bay scallops had recovered, and in 2017 and 2018 catches were over 100,000 pounds (meats) or about 10,000 bushels.  These catches came after colder winters, during Jan 14, 2018 an ice jam occurred Housatonic River requiring a state of emergency in Kent Connecticut.  This was joined by a similar ice jam on the Connecticut River two days later in the Haddam breach.  It has been decades since these cold weather incidents had happened here in CT.   

It was Mr. Hammond on Cape Cod that linked water temperatures to energy systems- in the 1880 to 1920 "hot term" oysters did well, in the colder 1950s and 1960s oyster sets were infrequent.  Quahogs did not do well at the turn of the century 1900s in Chatham, in "heat" MA, where Mr. Hammond farmed his oysters, but Chatham became a leading producer of the softshell clam. In the energy filled cooler 1950s and 1960s, bay scallops catches soared – soft shell clams retreated into the more sheltered and warmer salt ponds.

The softshell clam "retreat" had perplexed researchers for decades – how come Cape Cod had been a huge softshell clam producer in the warmer 1880-1920 to a minor population in the colder and stormy climate period of the 1950's. What wasn't considered was acid waters (rivers) organic matter in sulfate or the ability to access charged ions – related pH.  In 1956, John C. Ayers of Cornell and Woods Hole Oceanographic Institution in his 1956 article the same year titled "Population Dynamics of the Marine Clam Mya arenaria," was asking the same question, about Barnstable Harbor on Cape Cod.  On page 31 is found this section -   

"From earliest records until the economic depression of 1929, Barnstable Harbor had a history of an abundant Mya population, with huge augmentation by enormous sets of spat occurring at irregular intervals of a few years.  Between these huge sets the population in the harbor appears to have declined gradually. Huge recruitment irregular periods of more than one year suggests influx of swarms of spat, just ready to settle from some area outside of the harbor."

For many researchers the lack of sets was because of a lack of spat or not enough spawners – not a changed climate or a changed soil chemistry.

To make soil conditions even more challenging was rainfall and temperature conditions of climate.  These would also change the chemistry of marine soils, those with organic matter (silt) and the charges of ions needed to build shells.  The more organic matter the more negative the charge calcium ions have a positive charge.  The growth characteristics themselves are visible on the shell itself, those sands that produced quick growth (at times almost too fast) and smooth thin shells, versus the slower thick lumpy and rough shells of acidic humus or peat soils (those soils with high organic matter).  In time soils that once made ion transfer possible (CEC capacity) for calcium fixation to those that removed ions from shell – shell erosion from acids.  This is the habitat succession of soil – changes in the ability to hold calcium ions over time.

In a changing climate pattern (most fisher accounts mention cycles) temperature and energy could change algal composition (food) the amount of shellfish predators, and reproduction from temperature extremes or salinities, wet or dry periods. The soil succession therefore could be masked by several factors and give the appearance of over fishing when in many instances and over long periods of time it was a changing climate.

But one of the observations found consistently in the softshell clam historical literature is that not only sets improved in "new sands' but also growth.  Many reports mention slow growth of soft shell and hard shell clams (quahogs) in or near soils with clay.  Clay has a negative charge and the shell forming ions of calcium (cations) are positively charged.  That is the chemistry of the soil could change sometimes dramatically – and when combined with pH transitions great sets will without energy slowly die.  That is natural but often termed "over fishing."  This explains why one side of a river may catch a good set of clams but those areas opposite did not.  If the energy side is re-cultivated that would alter basic soil characteristics, rinsing out sulfides, increasing pH, and now reducing negative changed organic and clay particles.  Making it easier to obtain positive shell building calcium ions – clams here grow "faster" and have dense shells.  The depth of the cultivation is also a factor – shallow sets (soils not cultivated deep) can catch a set which may not last long, a deep cultivation event soft shell clams can live for years, digger cultivation can help keep soils from transitioning to those not favorable (especially if shell hash is present) but over time lacking a cultivation event, or in higher temperatures with organic matter (frequently called silt in the historical literature) these soils become negative for CEC (cation exchange capacity) and become acidic.  These beds in the historical literature are described as needing a "dug over."

For clams already set, growth becomes more difficult to access positive calcium ions – clams are starved so to speak for positive calcium ions because the soil has become so negative, the result, clams stop growing or growth is slow.  Shell erosion may now occur, the soil now takes back positive calcium ions by contact – shells thin out or erode (see ISCSR 2006 Niantic Bay CT hard shell clam experiment) shells now appear chalky, flaking, white, and new set clams may look perfectly formed but have extremely weak shells – so thin in fact a small pinch will crush them (Buttermilk Bay Hydraulic Clam demonstration Bourne/Sandwich Shellfishermen's Association 1982 Cape Cod).  Soft shell clammers who notice this are working soils with low CEC veligers landing in such a soil can last for only a few seconds in heat, and why black iron sulfide sapropels catch few clams and why honey sand or newly cultivated sands can catch so many.

Cation exchange capacity long studied in the terrestrial soil sciences has been largely absent in the marine fields, with calcium ions so important to our clam and oyster industries the ability of soil to make calcium acquisition easier or harder is of paramount importance.  Some studies of peat in the mid-Atlantic referenced the CEC – decades ago in a US Fish and Wildlife study of Back Bay National Wildlife Refuge in 1959.

Researchers noted that in low energy areas of Back Bay those that had reduced flushing (and increased clay particle residence time) had greater turbidity – as these clay particles are easily resuspended and fill soil pores.  Page 50 of the report titled Back Bay Currituck Sound Data Report Fish Studies, Volume 4 provides indications of acid sulfate soils and when exposed to air (oxygen) had pH levels increase.  While the clay soils had a high CEC and usually good for terrestrial plants but from suspected sulfides in these submerged soils did not support plant life.  Silt in these situations likely consisted of plant fragments surrounded by bacteria.  When placed on land for plant trials these soils did not support vegetation until the iron sulfides were eliminated.  Supplement to final report Back Bay Fishery Investigating July 1, 1962 to June 30 1963 reviews the impact of salt water intrusion after winter storms.

This is the same reaction of the placement of sapropel on land for agriculture and the consistent reports that clams showed the lowest (slowest) growth and setting from soils high in clay and therefore a high CEC.  Bays with low flushing with fresh water streams could act to fluccolate organics.

Water collected in Back Bay clearly illustrated the turbidity was from suspended clay particles (a greater residence time for these particles) and in the fisheries history related to flushing.  Although flushing and residence time describe different factors – ie flushing water exchange, residence time how long a particle stays in an area or water body.  Flushing time is an important factor for submerged vegetation including eelgrass in bays and coves with long restricted connections to the sea.  After salt water increased vegetation species was reported to change.

The Back Bay Study of 1958-1963 - printed June 1966

Is important to any study with similar organic/clay fractions and the influences of clay particles to the growth of shellfish and submerged plants such as eelgrass but other brackish submerged species as well.  In this study the water was collected and allowed to settle – show a dramatic difference in clay particle fractions (one of the few studies to do so, T. Visel) in suspended verses bottom soil samples. 

JOB IV-C Survey of the Distribution and Relative Abundance of Macroscopic Bottom Fauna.

#4 Clay – "Particle size less than .002 mm in a diameter.  As a soil textual class, clay contains 40 percent or more of clay, less than 45 percent sand, and less than 40 percent of silt.  This soil has great cohesion of particles.  A greasy feeling when rubbed between fingers, and it is easily recognized by blue-grey coloration.  In addition, it forms a characteristic cloud when suspended in water."

This study detailed shifts in vegetation after a severe March 7, 1962 storm which created 8 major breaks in the barrier beach.  The increase of marine soil clay particles is a feature of flushing (as those clay particles can remain suspended for weeks) and residence time how much water is exchanged daily or weekly.  For example, in a study of the Niantic River in 1977 by Michael Ludwig NOAA determined that the residence time in the Upper Niantic River was an incredible 27 days even though flushing was through a stabilized spit a few hundred yards from Long Island Sound.  (At this time thick growths of eelgrass were thought to have increased residence time harming scallops).

In some area, large volumes of water containing clay particles did not exit completely only to reenter during the next tide, due to the time clay particles can remain in solution – suspension.  The reentering clay particles add to those still being deposited by rainfall.  The buildup of clay particles in submerged soils is the cause of slow growth of bivalves as they being negative changed hold positive ions (such as those needed to build column shells) so "tightly" that growth or setting is negligible (termed a high CEC).  The clays also block soil pores reducing oxygen exchange in them – with organic particles and clays these soils in heat low flushing become sulfide rich.  The chemical changes from clays blocking oxygen into the oxic zone have dramatic consequences for submerged vegetation – as sulfide from peat/bacteria purge to the surface.  This is accelerated in heat and as sulfides diffuse rapidly in the water they can become airborne aerosols – the rotten egg smells of sulfide so prevalent in the historical fisheries literature – it also meant certain death for most bivalves.

Plants in general like a high CEC cation exchange capacity because their roots can access positive charged nitrogen ions.  That is opposite the biology of shellfish and submerged plants – they need a low CEC and live in lower organic matter soils.  Eelgrass in this case moves into newly cultivated marine soils, sandy and with good soil pore capacity, they can access or savage nitrogen from seawater – as roots do not have access to nitrogen ions in sandy soils.  As marine soils contain more organic matter – the nitrogen uptake in the leaves becomes secondary.  The CEC also can change from low to high with the buildup of clay particles.  The shells of clams change as acid forms from sulfides.

At first both eelgrass and bivalve shellfish thrive in well cultivated low CEC soils – here the absence of clay and organics is what facilitates eelgrass seed germination and alkaline (washed) soils following a series of strong storms or hurricanes.  In time these soils age (succeed) and what was good quahog setting and growing (harvest) grounds shows (over time) slow growth then no growth and often no sets.  The impact of clay particles upon the growth of bivalve shellfish has long appeared in the shellfish literature.

"Environmental Factors Affecting Growth in Venus mercenaria" (now Mercenaria mercenaria, T. Visel) David M. Pratt and Donald A Campbell Narragansett Marine Laboratory, University of Rhode Island – pg. 12 has this segment:

"All of these results corroborate our earlier findings (Pratt 1953), in showing a negative relationship between growth and the fineness of the sediment when fineness is expressed as percentage content of silt and clay, and also, in most cases, when other criteria of finesses are used, such as the mode of particle size distribution or the particle size corresponding to the first, second, or third quartile.  Of these various measures, the one showing the most consistent relationship to growth rate is the percentage of silt and clay."

In 1954, two US Fish and Wildlife researchers Harlan S. Spear and John B. Glude examined why areas (locations) in Maine's softshell clam industry experienced much different growth rates (now thought to be directly related to clay/CEC levels, T. Visel).  The study site included Bedroom Cove – low energy /clay habitat versus Sagadahoc Bay with more energy.  Perhaps one of the questions they researched is the prospect that some areas had bred slower growing strains but came to realize that following same size transplants the environment (soil CEC – T. Visel) not heredity was the deciding growth difference factor.

Although food availability was first offered for the growth differences the differences illustrates differences in soils – those with better soil circulation and pore space low CEC versus those higher in clay and a higher CEC – in organics.

Pg. 285 and 286 – Spear and Glude (Effects of Environment and Heredity on growth of The Soft Clam (Mya arenaria) (In The State of Maine).

"Statistical analysis (described in appendix B show that the differences in mean growth between test areas are highly significant.  It is safe to conclude that clams from a common origin adopt significantly different growth rates when transplanted to areas of different growth conditions.  The importance of environment as opposed to heredity in affecting the growth rate of clams is emphasized by these results.  If heredity were the cause of the differences in growth rates in various areas, we should expect clams that grew fast in their native beds to continue to grow fast when transplanted.  Likewise, slow-growing clams would be expected to continue their slow rate of growth after transplanting.  Instead, the growth rates of clams in this experiment varied with new environments.  For example, Bedroom Cove clams, which grew only 3.55 mm. in their native environment, grew 18.36 mm in Sagadahoc Bay.  At the same time, Sagadahoc Bay clams, which grew 14.48 mm in their native area, grew only 2.42 mm. when transplanted to Bedroom Cove."

Canals offer us perhaps the greatest opportunity to look at residence time and flushing two critical features to marine soil succession – the ability to quickly remove clay particles from land (this includes minute particles from ground winter street sand termed rock flour).  These particles clump bacteria with tannin a natural flocculant.  Here these water bodies lack energy and clays filled soils over time experience slower growth – dead bottoms and in heat with the buildup of black mayonnaise – the sapropels.  In these slow-moving water bodies, the first sapropels are formed and can accumulate rapidly.  Some of the first direct relationships of "soft sediments" were those with higher clay fractions.  (Remember earth soil science in many instances was not applied to marine study because marine soils were not termed as such until recently – T. Visel).  These shellfish growing conditions would be in stark contrast to sandy soils with bivalve shell bits or shell hash which tended to have lower CEC and better pH sore porosity.  In a key study of this soil relationship can be found in "Comparative Distribution of Mollusks in Dredged and Undredged Portions Of An Estuary With A Systematic List Of Species – published May 1970 Fishery Bulletin Vol 68 No. 2 by James E. Sykes and John R. Hall.  Both were Fishery Biologists with the Bureau of Commercial Fisheries Biological Laboratory St. Petersburg Beach Florida – A survey in Boca Ciega Bay Florida – a bay that has a barrier beach inlet history – sandy soils in higher energy and thick silt in low energy areas (most likely the beginning of black mayonnaise – Sapropel – T. Visel).  The difference in shellfish life between these soil types (referred to as sediments) is striking. 

Mollusk - Sediment Relations – (Sykes and Hall 1970) pg. 302 is found this section (my comments, T. Visel):

"Comparison of mollusks and bottom types showed that species and individuals were much less numerous in soft sediments of the canal than in sandy sediments in undredged areas of Boca Ciega.  Bay (table 1 and 2).  Canal sediments, which averaged 85 percent silt and clay, had 16 live mollusks in 14v samples.  Living specimens collected at the seven canal stations were the gastropods Nassarius vibez and Haminoea antillarum, and the pelecypods Brachidontes exustus, Anomalocardia cuneimeris, and Mercenaria campechiensis.  These species and 151 others were collected live from the 24 stations in undredged areas of the bay.  Sediments from natural bottom, which averaged 91 percent sand and shell, yielded 5,631 live mollusks in 93 samples.

Pratt (1953) suggested that soft sediments and associated hydrological conditions may be limiting because (1) rapid deposition has a smothering effect, (2) high organic content of soft sediments depletes dissolved oxygen, and (3) weak currents in areas of deposition are insufficient for the removal of toxic metabolic waste.  Comparisons of sediments and environmental factors (Taylor and Saloman, 1968) in dredged and undredged areas at sampling stations lead us to conclude that the soft sediment is the principal factor limiting the abundance and diversity of benthic mollusks in bayfill canals of Boca Ciega Bay.  Such sediments are as thick as 4 meters in waterways that were dredged 15 years ago" (about 1 foot accumulated every year – T. Visel). 

One of the factors of energy with barrier beach breaks or sluggish circulation in coves is the collection of the marine compost many times in the shellfish literature noted as suffocating blue mussels, oysters, soft and hard shell clams.  As organics collected, growth of clams slowed as documented on Cape Cod by David Belding a century ago.

Marine Soil CEC

In 1987, H. Karl Rask called me from Cape Cod to say that he believed had been the first completed hydraulic soil cultivation trials for CEC.  His interest was developing CEC as a measure to assess soil cultivation impact upon shellfish sets and growth.  He was focusing upon the removal of clay soil fractions and measuring CEC levels.  In a 1987, Rask reports:

"There is a link here to the excellent sets of shellfish found in new sand that has been deposited by storms or currents.  Clams (Mya) for example are a colonizer species and can quickly populate an empty area.  New sand is not only free of decaying organic detritus but also free of predators (especially the numerous small invertebrates that prey on shellfish larvae and newly set seed).  Hydraulic action can easily be seen to imitate some of these natural phenomena, and could be used intently to benefit our shellfish resources."

A year later, Karl Rask reports in Aquaculture Today (1988) and hydraulic cultivation trials in the Centerville River (Barnstable) Widows Cove in Wareham as follows:

"In all cases hydraulic harvest had distinct noticeable effects on sediment quality.  The major physical effect is the reduction in the percentage of fine particles such as clays fine silt and small organics.  This is reflected in an increase of grain size and a reduction in cation exchange capacity."

An increasing CEC and the soil aging process of higher clay fractions may compliment pH as major marine soil measures.  The presence of sulfide is a toxic soil measure for low pore space high organic fractions in heat.  Periods of cold contain higher levels of oxygen and more storms.  Marine soils could be subject to a rising sulfide dead line decades after a period of cold and storms, once again show clam sets that eventually decline and then stop.  That appears to be a natural cycle and explains the great sets in the 1950s and 1960s for quahogs – my view, Tim Visel.

We need to expand the concept of colder temperatures and higher pH to bay scallops.  Colder temperature strong storm frequency could alter acid bottoms to those with a higher pH.  The sudden and immense New York Peconic bay scallop die offs provide a connection to heat, but large sets of scallops appear after cold winters and strong storms in the historical fisheries literature.  In fact, the relationship appears more than coincidental or casual, but necessary.  Shallow bays and coves may support scallop fisheries only after cold winters and storm cultivation of their soils.  Storms are seen to create different soil conditions for benthic species including submerged vegetation. 

Soil chemistry including CEC has been absent reports that attempt to explain changes in bivalves and submerged vegetation populations, my view Tim Visel.


Appendix #1

Aquaculture Today, Fall 1988
"Getting More from Your Sediment Bottoms: The Effects of Hydraulic Harvesting"
By H. K. Rask
Regional Marine Resource Specialist
Cooperative Extension, University of Massachusetts


Pollution closures and the future of shellfish resources are receiving increasing attention.  In addition to closure restrictions, declining harvests can also be traced to poor setting and, especially, to the deterioration of bottom quality.  The result is considerable acreages of nonproductive bottom sediments.
In the case of chronic pollution, where there are permanent closures, shellfish are lost unless relayed to clean water for depuration.  When the beds are not worked, many areas suffer from increased sedimentation, followed by poor setting and recruitment.  A closer look at the sediment often reveals larger populations of worms and other invertebrates, instead of clams or quahogs, many of which are predators of the newly-set seed.  In addition, sediments can become anaerobic, sulfurous or otherwise chemically altered.

Cultivation a solution
   One obvious solution is to cultivate the beds improve sediment quality.  This was well known over 100 years ago, but is almost totally neglected today.
   In the past, horses or oxen often were used to cultivate the flats.  Today this can be done hydraulically, and tremendous yields have been found in areas that have been hydraulically harvested or naturally disturbed.  Recent work with hydraulic seed harvesters and other hydraulic gear also shows that cultivating the bottom enhances setting; good sets can also be found when storms, currents or dredging activities wash the sediments free of organic matter material and detritus.
   Although hydraulic gear is being used in many locations, elsewhere it still is prohibited or discouraged.  This study was undertaken in response to frequent complaints about resource depletion and environmental damage supposedly caused through use of hydraulic gear.
   Even before this study was started, some benefits from this type of harvesting were recorded. 
   There is a link here to the excellent sets of shellfish found in new sand deposited by storms or currents.  Clams (Mya), for example, are a colonizer species and can quickly populate an empty area.  New sand is not only free of decaying detritus, but is also free from predators.  Hydraulic action can easily be seen to imitate some of these natural phenomena.
Appendix #2


High Sulfide Levels Suspected in Turtle Grass Dieoff in 1994
Florida Bay Study
The Dieoff of Turtle Grass
Bulletin of Marine Science 54(3) 731-746 1994
RELATIONSHIP OF SEDIMENT SULFIDE TO MORTALITY OF THALASSIA TESTUDINUM IN FLORIDA BAY
Paul R. Carlson, Jr., Laura A. Yarbro and Timothy R. Barber

ABSTRACT
Sediment porewater sulfide concentrations in Florida Bay seagrass beds affected by the catastrophic mortality of Thalassia testudinum (Turtle-grass) were considerably higher than those of seagrass beds in the Indian River, Charlotte Harbor, or Tampa Bay Sulfide concentrations in apparently healthy seagrass beds were highest in fall and might have contributed to chronic hypoxic stress of Thalassia roots and rhizomes High porewater sulfide concentrations measured in dying areas of seagrass beds suggest that sulfide produced by microbial degradation of dying Thalassia might exacerbate stress on adjacent, surviving seagrass Sulfide concentrations in recent die-off areas initially were higher than in adjacent, surviving grass beds By the end of the study, however, the pattern was reversed apparently due to depletion of Thalassia-denved organic matter in the sediments of die-off areas In June 1990, high sulfide concentrations preceded a die-oft episode at one site, suggesting (1) elevated sulfide concentrations might be involved in a suite of factors that trigger die-off episodes or (2) elevated porewater sulfide results from death and decomposition of belowground Thalassia tissue before necrosis of shoots becomes visible In either case, elevated porewater sulfide concentrations might be of value in predicting die-off We conclude that porewater sulfide probably is not the primary cause, but a synergistic stressor, which has acted in concert with factors (such as hyperthermia, hypersalinity, and microbial pathogens) suggested by other researchers, to cause Thalassia die-off in Florida Bay.

Catastrophic mortality of the seagrass Thalassia testudinum Banks ex König (Turtle-grass) has occurred in Florida Bay since 1987. Robblee et al. (1991) estimated that 4,000 ha of highly productive Thalassia-dominaXea seagrass beds had been almost completely denuded, and an additional 23,000 ha had been affected to a lesser degree; recurring "die-off" episodes since 1991 have further increased the amount of Thalassia lost. Thalassia testudinum is the dominant macrophyte species of Florida Bay (Zieman et al., 1989), and loss of Thalassia could affect the function of Florida Bay in providing juvenile habitat for pink shrimp and other species and winter habitat for wading and diving birds (Schomer and Drew, 1982).

Among the possible causes for Thalassia die-off are increases in area, density, and biomass of seagrass communities due to high salinities in Flonda Bay resulting from water management activities and a decade-long drought in south Florida (Zieman et al., 1989). The same authors have also suggested that the lack of a major hurricane in the past 27 years has caused high levels of inorganic and organic sedimentation that, in turn, have restricted circulation and increased summertime salinity and temperature stress. A pathogen might also play a role in dieoff: Porter and Muehlstein (1990) reported the presence of a potentially pathogenic strain of the slime mold Labyrinthula in lesions on Thalassia leaves from die-off sites. Because many areas affected by die-off are located far from potential sources of anthropogenic nutrients and toxic compounds, pollution is not considered a contributing factor (Robblee et al., 1991).

As part of a collaborative research group studying Thalassia die-off in Florida Bay, we have focused on the role of sediment sulfide in the die-off process. Sulfide is produced in anaerobic marine sediments by bacteria that use sulfate as a terminal electron acceptor in the degradation of organic matter (Goldhaber and Kaplan, 1975; Sorensen et al., 1979).  High temperatures, abundant organic matter, and low sulfide-binding capacity can result in extremely high porewater sulfide concentrations in sediments of Florida Bay seagrass beds (Barber and Carlson, 1993). Sulfide is highly toxic to many plants and animals (Joshi et al., 1975; Smith et al., 1976; Bradley and Dunn, 1989; Koch and Mendelssohn, 1989) because of direct poisoning of cellular metabolism and indirect hypoxia due to reaction of sulfide with molecular oxygen.

We hypothesized that sulfide might play two roles in Thalassia mortality: (1) a chronic, but widespread, role of direct toxicity effects and indirect effects of hypoxia of Thalassia roots and rhizomes throughout Florida Bay; and (2) an acute role, during active die-off episodes, of amplified toxicity and hypoxia affecting surviving Thalassia as nearby, dead Thalassia roots and rhizomes are degraded by bacteria.  Although Syringodium filiforme Kutz (Manatee-grass) and Halodule wrightii Aschers (Cuban shoal-grass) might also be affected by die-off, Robblee et al. (1991) noted that dense Thalassia beds appear to be most vulnerable to dieoff.

We anticipated that, if sulfide-induced hypoxia contributed to the die-off phenomenon, Thalassia might be more vulnerable than other seagrass species because Thalassia has a high root:shoot ratio (Zieman, 1982; Fourqurean and Zieman, 1991). To determine spatial and temporal variations in porewater sulfide concentrations and the relationship of porewater sulfide to Thalassia die-off, we measured porewater sulfide concentrations in visibly healthy and in die-off-affected Thalassia beds at four sites in Florida Bay over an 18-month period from April 1989 to October 1990. We also resampled some sites in October 1992 to determine the effects of lower surface water salinity in Florida Bay on porewater sulfide concentrations.