IMEP 151 Part ! Bay Scallops Need Colder Conditions 1925 to 1975

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IMEP #151 Part 1: Bay Scallops Need Colder Conditions 1925-1975

"Understanding Science Through History"

Eelgrass Grants and Research Science

Bacterial Reduction Predicts Eelgrass Health

Bay Scallops Thrive in Cold Conditions and a Cold Nitrogen Cycle

Storms End Shallow High Sulfide Composting

Compost Fungal Disease or Bacterial Sulfate Metabolism

Viewpoint of Tim Visel – no other agency or organization

Tim Visel retired from The Sound School June 30, 2022 

Thank you, The Blue Crab ForumTM for posting these Habitat History Reports – over 375,000 views to date 

This is a delayed report – July 2022

Revised to April 2024

�

�A Note from Tim Visel

The year I was born (1954) the impact of a negative NAO pattern was having its full impact so were its numerous hurricanes.  Researchers were writing about global cooling and not global warming.  In 1976, Harry van Loon was finishing an article about global cooling reflecting the NAO and The Connection Between Trends of Mean Temperature and Circulation at the Surface (Part 1).  The return to cold had happened in the early 1920's.  In 1924, Albert Defant, an Austrian oceanographer, is credited as being the first researcher who described the atmospheric circulation over the North Atlantic Ocean.  We refer to Defant's research as the "polar vortex" a century later.   The bitter cold winter of 1922-1923 took New England by surprise – they weren't accustomed to such cold.  It was the change from mild to bitter cold that was much of the shock.   Those following the bay scallop fisheries were just as surprised.  Consider the comments of fishery managers in Rhode Island on the immense bay scallop crop that followed the bitter winter of 1922-1923.
At this time the winters in New England turned sharply colder- it is thought that thick ice signaled scouring and moving sand bars in coastal coves and river mouths.  This is when winter ice spearing for winter flounder happened - when thick ice formed and adult flounders came to brackish water to spawn (See The Search For Megalops series posted on The Blue Crab Forum^TM Report # 1, January, 2012).  It was common to equate a mild winter to be a good thing for all species because it was better for us.  This is expressed in the Rhode Island Fisheries records regarding the bay scallop catches after a series of bitter cold winters.  Nowhere near the catches of the 1870's but much more than the 1890's when the bay scallop virtually disappeared as a Rhode Island fishery.  The sudden and dramatic return of the scallop to inshore waters in which could be subjected to freezing conditions.
 
This segment from the Rhode Island Annual Reports of the Fisheries Commissioners highlights the surprise of the huge 1924 bay scallop crop after the bitter winter of 1922-1923 a sudden departure from relatively mild "winters" immediately preceding.  Commissioners report on the huge bay scallop crop in excess of 300,000 bushels "in spite of the fact that the winter of 1922 to 1923 was one of the most severe that we have had in a number of years."
 
The 1930's would see the beginning of a negative phase of the NAO.  As cold waves hit warmer air over the Gulf Stream low pressure systems were energized into the much feared Northeasters that now hit the coast.  It is at this time bays and coves became "larval traps" for billions of seed scallops moved by these strong storms.
 
Small seed scallops driven by strong northeasterly winds and flooding surges carried with them countless scallops into the shallows.  In areas with restricted tidal flows, it trapped these scallops in areas in which they were once scarce.  The bay scallop in shallow water is at the mercy of birds, crabs (especially the green crab) fish and benthic predators such as the starfish.  During colder winters, these larval traps could produce adults and therefore a small boat fishery, but not without huge seed loss.  This is the time that scallop reports include references to massive seed transplants from the shallows - either desiccation in a huge wrack of small seed or freezing in shallow waters.  It is at this time small boat fishers helped move millions of seed scallops from the shallows to deeper water in the hope this seed could survive the winter.  No one it seemed introduced climate change into these natural events (seed loss) or why the increase of the bay scallop fisheries happened when it was so cold.
 
In the decades to follow, cold returned to New England and so did the bay scallops.  In the fisheries literature you can see increases in comments to saving bay scallop seed from freezing – but no mention of the connection of cold conditions to the scallop rebound.  In the 1900's, scallops had retreated from southern New England to the cooler Cape Cod and Island waters.  Compared to the 1870's, the bay scallop catch had greatly diminished.
 
The bay scallop crop was a great fishery for small boat fishermen – here, hand hauled "light" dredges (no cutting bar but link chain) could be towed not designed to "dig" but to "skim" over the bottom.  Bay scallops were surface dwelling and did not dig into the soil like clams or oysters that packed into dense beds.  Here, the cost of harvesting bay scallops in shallow water was modest, sometimes just a skiff dredge and outboard motor.  John Hammond, an oyster planter in Chatham, MA, once described to me that bay scallops were known as the "Christmas Crop" as by the end of December ice made catches difficult.  With the return of mild winters, this winter fishery declined and then "failed" for the small boat fishers of Chatham and southern New England.

Two cold water species "winter flounder" and the bay scallop have been linked to thick eelgrass meadows and their decline to the loss of eelgrass rather than climate.  This viewpoint is considered accurate when habitat associations are grouped together.  Eelgrass prefers colder well cultivated marine soils - so does the bay scallop and winter flounder.  Winter flounder prefer alkaline habitats -those containing bivalve shell and low in compost fungal species.  They return in the winter to take advantage of clean algae mostly kelp and cobblestone bottoms in higher currents to maintain oxygen levels in which to lay eggs. These nursery habitats have been well studied in the literature.
 
Bay scallops also prefer colder water alkaline habitats as well.  This cold influences the bacterial release of nitrate, the nitrogen compound so important to nourish algal foods that bay scallops need.  They prefer those habitats void of sulfide as even minute levels of sulfide are poisonous to bay scallop seed.  In areas of restricted flows, it is known that bay scallops can starve or stunt and scallopers once avoided eelgrass areas as poor meat quality and low weights.  Channel scallops in faster flows grew fast and large and that also appears in bay scallop habitat accounts.
 
Eelgrass also does better after severe storms as they both cultivate the soil and as a true grass it shares many plant characteristics to its terrestrial cousins in turf or sport field monocultures.  As storms during colder and storm filled weather naturally cultivate marine soils it also does well from massive seed dispersal.
 
During long periods of heat or sharp heat waves, seawater and marine soil chemistry change and can become toxic to eelgrass.  This is noted in the marine habitat and terrestrial habitat literature as death rings associated with compost fungal disease.  Very hot seawater and high organic contents of marine soil can foster the formation of sulfide root toxicity.  In terrestrial turf, it is termed black layer disease as early eelgrass researchers termed it the "wasting disease."   The chemistry and toxic impacts of root sulfide rot is almost the same.  Organics collected by eelgrass peat now provide the food for sulfate reducing bacteria when oxygen levels drop and most evident in the summer when dissolved oxygen levels in seawater are at a seasonal low point.  The rise in sulfide is what coastal residents experience on August hot nights with little shore wind.  They often mentioned that the marsh smells like rotting eggs.
 
The truth of the matter is all three species do better during cold for very different reasons and for the scallop and winter flounder not defined by the presence or absence of eelgrass.
 
It is the bacterial aspect of sulfate reducing bacteria and sulfate metabolism that produces the greatest change in habitat quality by the depth of compost and sulfur content of marine composts.  A deep organic compost effectively seals the soil from circulation of oxygen and increases the chance of sulfide formation.  That is why it is so important to winter flounder to live in a sulfide free habitat.  Many studies happened in late winter or early spring when oxygen levels are at a seasonal high.  Many winter flounder studies happened at this time as the presence of winter flounder was high and actually present to be studied.  Few studies have been done in late summer when oxygen is at a seasonal low and so important to small flounder living in the shallow nurseries.  This situation is evident as young of the year (think year class) die out or is considered a failure.  Adults may still return in the spring with cooler water lay eggs only to have the fry killed as the summer progresses.  Fishers notice this decline of year class failure as the size of the catch transfers to all adults.
 
What was happening is as the last adults are caught or age out of the fishery, very few young (pre-spawning age) are available to replace them.  The result is a crash in population that was set in motion years before.  It is masked by the fact that cool winters may allow adult winter flounder to return and spawn but higher summer temperature kills most of the young.  Series of consistent (young of the years) failures leads to a fishery collapse.  Often it is thought that overfishing had happened but ignores the loss of habitat that preceded it.  When a habitat failure happens, almost any fishing can be considered overfishing but fails to recognize the role in climate in fishery declines.  This had little to no connection to eelgrass in fact in high heat eelgrass peat contributes to the rise of ammonia and often devastating growths of macroalgae such as Ulva species called sea lettuce.  In this case we may need to reverse the phrase guilt by association to innocent by association. Eelgrass presence or absence can be a part but not conclusive to the absence or presence of these two seafood species.
 
Although many reports highlight the role of eelgrass for habitat quality or other species, it should only be considered an indicator and not conclusive to habitat requirements.
 
Similar climate changes influence the bay scallop which prefers good currents for feeding and the near absence of sulfides.  Young winter flounder can exist for short periods in warm shallow water by use of a special bottom tail skin secondary oxygen transfer pathway it can use when oxygen levels drop. Eelgrass can be killed by sulfide during long periods or heat but is part of a local marine compost that kills its roots.  None of these factors are all controlled by human interactions- my view, Tim Visel.
 
Is Eelgrass a Cure All Tonic for Coastal Ills?
If someone was shown a picture of a toy water pistol (squirt gun), they would quickly dismiss it as a useful tool in fighting an active forest fire.
Now, take away the picture and just use an inappropriate description instead as shown below in quotes:
"A portable self-contained water delivery device capable of propelling water when activated."
All the above is true but when compared to a drenching rain storm or a modern six-wheel fire engine, the comparison appears silly, even ridiculous.  No one would hold this device responsible for putting out fires.  So, one may wonder why so much has been placed upon the burden of eelgrass, a submerged aquatic grass, to fulfill so many coastal responsibilities that now may include (a partial listing):
o   Slowing sea level rise
o   Slowing global warming (absorbing CO₂, releasing oxygen)
o   Providing essential fish habitat
o   Helping to restore scallop populations
o   Reducing turbidity in shallow waters
o   Storing carbon (termed blue carbon)
o   Preventing erosion of beach sand
o   Oxygenating seawater for other species
 
And a few years ago, eelgrass was praised for combing out human pathogens on its blades while releasing oxygen.  SCUBA divers near eelgrass were found to be less sick than other divers (See Science 2017, Lamb et al., pg. 731-733, Seagrass Ecosystems Reduce Exposure to Bacterial Pathogens).  Immediately, these types of claims cause me to think of the scientific method, variables, controls and experimental trials.
Many eelgrass articles include a clear high contrast picture of "clean and green" eelgrass.  When that happens, I see a water pistol.  In 2014, The Boston Globe Newspaper^TM even ran an article titled "Eelgrass Could Save the Planet."  That's quite a burden for eelgrass to carry.  I have written about a previous era about elixirs and special potions to cure various ills or reduce the pain of inflamed joints.  We know that time before the 1906 Pure Food and Drug Act as "Snake Oil" cures – a period in which "medicine" was promoted to those in need but with no requirement to provide proof that it could deliver its promise.  As once a bottle collector, I was familiar with Dr. Kilmer's swamp-root kidney liver and bladder remedy from old bottles unearthed in grade school.  Kilmer and Company also sold Ocean-Weed Heart Remedy – yes, it shows eelgrass on labels as a "heart remedy-blood specific."  The actual recipe, I think, has been lost however.

Eelgrass was considered a "weed" at the turn of the century (1900), and many reports can be found blaming it for fouling beaches, creating smells, causing lung disease (wrongfully, T. Visel) and killing shellfish. In one documented Connecticut example, heat waves caused massive sulfide gas releases in the 1880s and 1890s along Connecticut's coast.  Before, bacteriology ended the Miasma Theory of disease vectors of breathing bad or "foul smelling airs."  At this time, the science community and the public believed that breathing bad smelling "foul" air spread human disease.  In one case history that occurred in the Poquonnock River, Groton, CT in 1880, a local historian Carol W. Kimball documented this outbreak of Scarlet Fever caused by the bacteria Streptococcus A.  Groton residents then blamed oyster culture for the dreadful stench coming from the Poquonnock soft river bottom, while Groton oyster growers blamed the thick growths of eelgrass Zostera marina (See The Poquonnock Bridge Story by Carol W. Kimball, 1984, Library of Congress #84-82324).  Local and state medical and researchers testified against the oyster growers and Kimball mentions on page 122 the following – (my comments, T. Visel):

"Dr. Chamberlin (State Board of Health, T. Visel) warning that it would be dangerous to remove the brush (Brush was used as an off bottom oyster spat collector, T. Visel) except in very cold weather.  He said it must be done with thorough disinfection to avoid dangerous gases liberated from mud, water and brush."

Although the growers continued to explain that growing oysters was not the cause of the Miasma or Scarlet Fever disease but were forced to remove all brush and oysters that were growing upon them.  This was a classic sulfide gas release by the action of sulfate-reducing bacteria in high heat.  The blame was also placed on thick eelgrass that slowed tidal action, causing stagnation and the discharge of "offensive" gas release (See Appendix #3).

Thick growths of eelgrass are noted in the historical fisheries literature for the next four decades.  The oyster industry recorded many instances of eelgrass moving into and completely covering oyster and clam soils.  As the climate cooled into the 1920's, thick blankets of eelgrass died off suspected to be from composting fungal infections.  Heavy wracklines now appeared on New England shores.  In 1922, Irving Field (US Fish Bureau) called eelgrass the most "destructive weed" documenting complete burial of mussel beds.
It was not then held in high esteem and no one was suggesting that eelgrass could save the planet.  So, what happened?  Much of the eelgrass reporting is based upon observations that are subject to many variables as to make them unverifiable.  It is often reported that eelgrass was a species-specific spat collector for the bay scallop veligers that would attach a thin fiber thread to the blade and that is true.  What is not mentioned is that in the absence of eelgrass, bay scallops attached themselves to other vegetation, even natural fiber ropes (Marshall, 1960).  One survey on Cape Cod (1980's), I found by towing a scallop dredge in the Centerville River a discarded Christmas tree covered with a thick set of bay scallops.  So many scallops were collected on discarded pine trees, it became an off-record habitat enhancement method for collecting bay scallop spat.  It was soon commercially sold as "Christmas tree rope" or tape and is still marketed.  You can see the problem if this was portrayed as a natural scallop collector because its presence was unpredictable and not natural.  The same could be said about eelgrass – some of the periods that eelgrass was dominant, bay scallop populations were very low.   Even when corralline red algae (species) was found to contain substances that attracted scallops for setting, it is rarely mentioned that eelgrass does not.  It is the low weight molecules termed the bleeding grass syndrome.  A similar release (smell) is caused by cutting terrestrial grasses.

It is thought that similar chemical clues are released from torn corralline red algae.  It is thought that storms rip these plants like cut grasses (See Corralline Algal Rhodoliths Enhance Larval Settlement, Steller & Caceres-Martinez, 2009).  When you examine the bay scallop production history (New England), you see that the highest bay scallop production comes during brutal cold winters or very cold winters with powerful storms.  It is during these very cold periods in which industry records indicate (confirm) that dredge fisheries existed in 25 to 35-foot depths (See IMEP #52: Narragansett Bay Deep Water Bay Scallop Habitats 1870's, posted July 27, 2015, The Blue Crab Forum^TM, Fishing, Eeling and Oystering thread).  The biology and habitat conditions appear to conflict – we imagine extreme cold as a hardship but for the bay scallop times of great sets.  These storms create conditions of large catches in shallow waters, which can act as a "larval trap."  Small scallop seed thrown into shallow water leave it vulnerable to freezes.  If you have ever seen this, you marvel at the amount of seed left to perish.  This is also noted by fisher efforts to save this seed from death by transplanting it back into deeper waters.  These three items, large catch, bitter cold and seed mortality can be seen in the 1870's and again in the 1960's.  In periods of extreme warmth (heat) records bay scallop dieoffs as adults in areas of extreme low, dissolved oxygen and sulfide enrichment.  Bay scallops will have sulfide staining black to gray with scallop shells still paired (i.e., the "wing scallops").  I noticed this happened in Green Pond in Falmouth, Massachusetts (Cape Cod) in a heat wave, which also presented the oft cited "smell of rotting eggs."  It is the salt ponds that act as larval traps in extreme cold provides a positive habitat condition food (sufficient nitrate-requiring algae) greater dissolved oxygen and a salinity block to the major bay scallop predator the starfish, Asterias forbesi.  In cold and frequent storms, the chances of a strong thermocline (water density division) is reduced letting oxygen reach the bottom, and provides needed nitrate for food algal species.  (Many shellfish hatcheries use nitrate-requiring algal strains as culture food.)

Although eelgrass, Zostera marina, is frequently noted as a significant bay scallop spat collector, it is a poor habitat type for the bay scallop.  This submerged grass reduces currents and feeding opportunities.  This historical fisheries literature contains accounts of "grass scallops," those scallops with small meat size (eyes) from reduced feed and feeding results in eelgrass as compared to "channel" or deep-water scallops.  Bay scallops that set on eelgrass can be subject to blade attack by the green crab.  In extreme heat, any organic matter collected by eelgrass as a natural peat-building activity can purge sulfides and sulfuric acids, killing both adults and newly set spat.  It is in the salt ponds that this water chemistry change is first seen.  They warm up the fastest – may have a greater residence time for compost ammonia (a nitrogen compound not preferred for algal food) and reduced flushing, impacting dissolved oxygen levels.  In times of heat, these habitats fail for the bay scallops; in times of cold, they sustain a huge shallow-water, small boat fishery.  The best conclusion to the bay scallop-eelgrass connection is that they both benefit from "soil renewal" from cold water.    

Other variables include energy, temperature and the chemistry of estuarine organic composts capable of purging sulfuric acids.  The growth and health of eelgrass (a true grass that flowers under water) is directly related to the soil chemistry in which it lives.  It is a natural part of habitat succession – soil conditions can change, such as drought, floods and fires influence terrestrial grasses.  Probably the most accurate representation of eelgrass is like its terrestrial counterparts, it is aggressive and opportunistic in terms of soil quality.  For decades, researchers have known that marine soils high in clay and organic matter were not suitable soils overall.  One of the studies that identified this soil vegetation condition for Connecticut researchers was done in Back Bay – Currituck Sound 1958 to 1964 by John L. Sincock.  This series of reports detailed periodic barrier beach breaks that greatly changed vegetation growths (important for duck hunters) by way of soil transitions, especially silt and organic matter content.  A soil comparison illustrates the influence of energy (storms) upon soils before and after a March 1962 storm:

            Before March 1962 –
            .4% sand, 32.7% silt, 66.9% clay, 7.7% organic carbon
            Organic carbon lost upon burning
 
            After March 1962 –
            13.8% sand, 62.8% silt, 23.4% clay, 3.74% organic carbon
Organic carbon lost upon burning
 
This soil aspect is missing from many eelgrass reports that coastal energy can change soil structure and combined with temperature changes gives the concept of succession cycles credibility and that eelgrass (with many other species) needs energy to survive in long-term habitats.  Quite simply, eelgrass needs soil renewal by way of storm energy.  It needs this renewal periodically like some plants need fire for the same successional purpose.

I was recently in a meeting with Audubon Connecticut regarding living shoreline proposals and eelgrass restoration came up.  I mentioned soil chemistry and stability as key study features.  For eelgrass, soils should have periodic disturbance (this counters most eelgrass study reports) to keep the soil healthy for eelgrass, cultivated with low clay (good soil pore exchange) and low organics to slow bacterial sulfide formation in heat.  Some plants need huge energy events (fires or storms) for them to grow and produce seeds that may lay fallow for years, even decades.  These are known as the forest fire wild flowers, which bloom after fires.  Apparently, Marsh Pink, a salt marsh plant that is rare in Connecticut, was subject to a large restoration project in 2022.  Unfortunately, that planting effort failed to produce success but when earth moving and mowing equipment was brought in, this tore into the top peat/marsh surface exposing Marsh Pink seeds below (thought to be long buried) to the surface where they grew vigorously and covered the disturbed portions with thick pink blooms.  It was a significant habitat finding and promptly reported out to the research community.  The 33-acre restoration project in Great Meadows Marsh (Stratford and Bridgeport, CT) and was funded by a $2.5 million EPA Long Island Sound Study grant with total funding approaching $4 million.  A January 4_, 2024 article written by Lauri Munroe-Hultman mentions this unexpected result (See Appendix #4).

This result is contrary to our own habitat bias as we crave stability in habitats.  That is essential to our survival.  Imagine agriculture built upon an annual crop only to have multiple crop failures without warning.  That is the basic bias that we have around coastal habitats.  During storms, we often see the waste of fish and shellfish thrown up high into a wrackline.  Storms long known to be destructive to life and property occur along the coast, giving those who live there views to this shoreline damage.  Therefore, it is difficult to perceive that some species thrive after storms or those species that need coastal storms to prepare soils for sets.  This is clearly illustrated in the Rhode Island fisheries history for the quahog Mercenaria mercenaria.  The largest sets of hard shell clams occurred after a series of strong hurricanes.  This aspect can also be seen in the coastal bay scallop fisheries when storm tides drive bay scallop seed high into the shallows.

The same bias exists around forest fires.  We see horrific damage and resource loss.  It is hard to believe that some plants benefit from fire but many do.  From the Audubon account, during this meeting the Marsh Pink bloom in areas in which surface cuts were made in the peat – this was quite a surprise.  The 3,000 Marsh Pink transplants grew at first but then perished.  In the disturbed areas of peat, quite the opposite occurred.  Marsh Pink bloomed heavily.  It is much credit that this result was reported cut, as much of the previous marsh peat policy was minimal or no disturbance.  Some plants need disturbance to complete their life cycle, and one of those plants is eelgrass.  Eelgrass, over time, thrives in storm-washed soils, and as storms subside and clay fractions fill soil voids, eelgrass dies off.  Sudden heating in high organic soils (those soils with higher than 10% organic matter) sustains bacteria that mobilize sulfate as a source of oxygen and waste sulfur that forms hydrogen sulfide H₂S, a plant poison.  When oxygen (dissolved O₂ form) is reintroduced, sulfuric acid is formed adding more stress for the plant.  Eelgrass is actually helped by strong storms, preparing marine soils for future eelgrass growths.  Research conducted by Chris Pickerell, Cornell Cooperative Extension-Cornell University, reported in 2017 during an EPA Habitat Committee at Hammonasset State Park that healthy eelgrass meadows had organic matter content (as a percentage) below 2%.  Areas with failed eelgrass transplants had organic matter content over 5%.  Declining/lost eelgrass meadows were over 6% organic matter (See Eelgrass (Zostera marina) Current Distribution, Restoration and Management - PowerPoint presentation, February 8, 2017, Meigs Point Nature Center).  The return of eelgrass from the 1920's until peaking between 1955 and 1970 came after a series of strong coastal storms.  It is thought that besides "new sand" after barrier beach breaks, other areas were washed of high organic soil fractions, renewing them as to their ability to sustain eelgrass.

Small boat (skiffs and scows) fishers watched this happen because they fished in shallow waters and noticed the habitat change.  The oyster industry, for example, mentions the eelgrass succession of oyster habitats from 1880-1920 when eelgrass growths were reported as "dense" or "thick."  John Hammond had a personal experience with this soil preparation effort in the late 1960's during a time of great eelgrass expansion on Cape Cod (See the State of Massachusetts Study of the Westport River Massachusetts, John D. Fiske et al., May 1968).  Eelgrass was found to suffocate hard clams and was growing amongst planted seed oysters (two-year old bedding stock).  Eelgrass was slowing currents, reducing growth and increasing the collection of organics on this oyster grant.  To rid his oyster grant (lease) in the Oyster Pond River of eelgrass growths, he arranged for a small outboard powered skiff to pull "cultivators" over the oysters to pull up eelgrass plants.  It was during this time that Massachusetts (and other states) reported on similar eelgrass reduction efforts.  He hired two high school students to pull drags "cultivators" over his growing oysters to lessen what he described as "fouling."  The plans and sketches of these cultivators resemble turf grass dethatchers and can be found in the end of A Review of Fisheries Histories for Natural Oyster Populations in Tidal Rivers on pages 44 and 45 (See Appendix #3).

He noticed that after several days of cultivating the surface, eelgrass was cut, but over the summer and fall, eelgrass grew back stronger and in different places.  Mr. Hammond concluded that the cutting and disturbance in sandy shell bottom had actually improved soil conditions for eelgrass very similar (if not exactly the same) to dethatching machines for lawns and golf turf.  I ran into similar eelgrass peat on the north shore of Cedar Island in Clinton.  Root tissue and decayed plants were three-feet deep.  Here, the eelgrass was dying in the mid-1980s.  This area had transitioned from a high energy barrier beach break to a low energy habitat that, over time, trapped silt and organic particles.  It was Mr. Hammond, who noticed that sulfide was deadly to eelgrass and first described a "sulfide deadline," which details grass/peat bacterial disease that forms sulfide.  This process is exactly the same that impacts terrestrial turf as soil pores collapse (from collected fine particles) and create "black layer disease" in terrestrial grass research.  To eliminate or reduce black layer disease, turf punch core aerators are used to open up dense roots and allow more oxygen into the grass/root zone.  This helps "defeat" those bacteria that do not need oxygen to respire and allows greater numbers of oxygen-requiring bacteria to survive.  What Mr. Hammond experienced was a marine type of aerator and one that benefitted eelgrass – contrary to most non-disturbance eelgrass policies when compared to turf research and terrestrial field studies.  Soil renewal processes are critical to eelgrass "soil health."

I often write about sulfate-reducing bacteria because of its impact upon sea life that need oxygen.  EC #8: Salt Marshes, A Climate Change Bacterial Battlefield, posted September 10, 2015, The Blue Crab Forum^TM, attempted to portray this as a struggle to see which bacteria can live in sulfate-rich environments.  There are other examples – "sewer gas" in sewer lines also subject to low oxygen levels.  The waste water treatment industry monitors hydrogen sulfide levels in sewer lines for the danger of sulfuric acid formation and subsequent damage to metal piping.  Methane is also monitored for explosion risk and high levels of ammonia is a warning that oxidation is declining.  All three gases are related to bacterial action on carbon chains bound in plant tissue.

In the marine environment, oxygen bacteria are at a disadvantage as they cannot directly access oxygen in the atmosphere, instead relying on the amount of dissolved oxygen in seawater.  Because warm (hot) seawater does not hold much oxygen, sulfide formation occurs in our area at the maximum temperatures – late summer and fall.  Instead, a less efficient bacteria has developed the sulfate reducers that split apart a sulfur atom surrounded by four oxygen atoms or SO₄.  Every sulfur that is split off releases oxygen for carbon digestion – deriving energy in this process.  This energy is greater with oxygen and entire books have been written on how to control the bacterial heat of a terrestrial compost pile (See Composting Guidelines for Compost Temperature). 

The presence of sulfate provides a lifeline to those bacteria that have evolved processes to use it.  Sulfate is readily available in seawater and is often described as "non-limiting" but deep accumulations of plant tissue form a barrier to oxygen-requiring bacteria.  This is why terrestrial composters often turn over the compost pile to introduce (oxygen) oxidation and maintain composting temperatures.  We cannot see bacteria because of their size (To see colony forming units (CFUs), you need a microscope).  But if you ever laid out a cut turf lawn, you quickly realize the heat of billions of bacteria breaking carbon chains – the turf rolls can become hot to the touch.  It is basically the same bacterial response on a home garden compost bin.  This heat is bacterial, and if it gets hot enough, can kill the cut turf before it is placed and watered.  This thin layer of turf is fully exposed to oxygen and is responsible for such quick heating.

The species of bacteria responsible for black layer disease have been found to include Desulfovibrio species (See Turf Pest Diagnostic Laboratory – Black Layer, Penn State University).  These are anaerobic, sulfur-reducing bacteria.
 
The Bacteria of Terrestrial and Aquatic Soils - Why the Process for Bacterial Reduction Is So Important to Agriculture and Aquaculture
It is the bacteria in soil that allow roots to uptake forms of nitrogen and it is the bacteria that makes some soil more productive than others.  Plants can be grown in sand but low in organic matter naturally occurring nitrogen is quickly exhausted.  Additional nitrogen is needed (fertilizer) but lacking organic matter (humus) soils can become excessively drained.  Nitrogen quickly moves in these soils and enters water tables (natural nitrogen is moved into the groundwater as well).  Thus, soils with organic matter and some clays to retain moisture are some of the best soils for agriculture, such as flood plains.  After thousands of years, each flood or high-water event would leave a layer of clays mixed with organic matter.  Here in years of moderate rain, bacteria would thrive and these soils become highly productive.  However, in floods water would fill soil pores, sealing it from atmospheric oxygen, killing the plants but also if the flood lasts long enough, killing the soil bacteria as well.  Therefore, early colonial efforts to reclaim poorly drained soils for agricultural use did so not only to produce dry enough conditions to prevent seed from rotting but also to allow oxygen to enter these soils, making it possible for oxygen-requiring bacteria to live. 

Floods could kill plants but also kill the bacteria in soil.  Many areas that had wetlands were transitioned to dry land by way of trenches, ditches and small ponds to remove water and lower the water table.  Lowering the water table in Europe, especially Holland, had been practiced for centuries.  These agricultural soils are known as "mounds."  When colonists arrived in New England and gazed upon the coastal salt meadows, they sought the same impacts – diking and draining made agricultural use possible (use of sluice gates) and allowed at seasons the harvest of salt hay.  Did they fully realize the change in bacteria in these marsh peat soils?  Most likely they did not.  That would be the province of soil scientists in the future.  But some impacts were noticeable when coastal marshes drained in high heat, they seemed to shrink and sink.  Peat, largely organic matter that sustained plants, accumulated because the bacteria that lived in poorly drained peat were slower "consumers" than oxygen bacteria.  They could not keep up and organic deposits rose.  Now, peat subjected to oxygen hosted a new type of bacteria, ones that nitrified the soil, produced nitrates and in that process aided plant growth.  But the faster bacteria could eat the peat as well, causing it to "sink."  The slower bacteria, often ones that utilized sulfate and not oxygen, retreated deep into the peat away from the oxygen containing "aerobic layer."  While peat soils now had the capacity to produce food or forage (hay) crops, they also began to sink.  Bacteria now consumed the marsh itself, and in heat, any very low oxygen seemed to turn peat into a black, soupy mixture.

Claude E. Zobell in his paper on bacteria in Marine Sediments, pg. 421, mentions this process (See recent Marine Sediments, edited by Parker D. Trask, Copyright 1939 – published in 1955).

Decomposition Caused by Bacteria

"Various physiological or biochemical types of bacteria have been demonstrated in the sediments that are capable of attacking most kinds of organic matter. The rate and end-products of decomposition of the organic matter depend upon environmental conditions and the types of bacteria that are present ... More resistant fractions of marine plants and animals such as lignins hemicellulose-protein complexes may be only partially decomposed to give rise to marine humus."

Soil performance was well known, nitrogen being the key criteria on crop yields, but also in time the need to keep the soil bacteria nourished as well, i.e., the use of manure.  But the nutrient value of manure and the indirect value of bacterial nitrogen from it was low.  Manure had to be first broken down into fragments so that bacteria could better consume it, or what we call today compost.  Some organisms besides bacteria consumed it, worms and fungi for example.  Composting made soil introduction easier as well.  Fresh manure had ammonia in it, and ammonia could damage root tissue (it is extremely alkaline, basic with a pH of 13).  It can also destroy plant and animal tissue, and a powerful version of this is lye (it is also toxic in a gas form).  Thus, to reduce ammonia, soils would be "aerated" or cultivated to introduce oxygen to help the bacteria process it into nitrates – the soil pores, void or spaces between minerals in a soil became an important cultivation aspect.  Mucky, clay-filled sticky submerged soil pores did not allow good air/water exchange and made for "poor" agriculture soils.  However, peat once drained and open to air supported bacteria that make them productive.  The use of the Florida Everglades for the harvest of sugar cane was made possible by draining peat and plants, namely sugar cane after bacteria (aerobic) lived in them.  Flooded fields today need time for the surface water to reside and soil bacteria to recover.  Soils were also subject to other bacteria killing impacts from the heat of forest fires.

High temperature forest fires (slow moving and extremely high temperatures) destroy bacteria that fix nitrate but also melts wax fractions of leaf litter (oak leaves have very high wax levels).  This seals soil pores, making rainwater penetration difficult after fire.  This increases mud flows after heavy rains.  After horrific forest fires in 1910 – The Northeast Experiment Station was created in Duluth, Minnesota in 1911 – for the study of forest fires (Thompson, 1925) and soils.  M.J. Thompson Effects of Forest Fires on Land Clearing and Crop Production – 1925.  In 1910 in extreme heat and drought, 3 million acres burned, killing nearly 100 people.  These horrific fires destroyed farms, killed animals and the people who ran them.  They also killed the important bacteria important to agriculture – they also "killed" the soil.

It is this battle to keep the good bacteria alive that agriculture invests so heavily – pH monitoring, cultivation, organic matter and soil pores that make a soil "healthy" and "productive."  We don't often hear about this bacterial struggle.  Most realize the need to feed the soil organic matter or the importance of organisms in the formation of compost but few realize the systems we develop to control this organic matter reduction (such as waste water treatment facilities), or in the case of aquaculture, a reproduction of nature's natural bacterial filters along the shore, beaches, coves and bay bottoms in a building.  Perhaps aquaculture systems are the ones most studied and the aquarium industry closely following.  In aquaculture, the loss of the biological filter usually results in a growing increase in ammonia and increasing pH.  In time, the ammonia level allows new strains of bacteria to form and any sulfate is consumed, and the smell of sulfur signifies toxic conditions; water may turn black and dead organisms (fish/shellfish) resulting.  The loss of nature's filter system in large areas in a warming temperature increase can be catastrophic, thus the danger of a warming planet.

But what happens chemically when nature's coastal filters are destroyed?  What is the impact upon marine soils, its habitats and the organisms that live in it or near it?  It seems the bacterial populations also change – our hurricanes are similar to forest fires, massive changes in habitat and bacterial populations.  Just as terrestrial soils that take time to recover from a forest fire or flood – i.e., re-establish bacterial populations so also do marine soils, especially when it comes to which bacteria will live in them.  The processes are almost identical.

Two major oxygen related pathways exist: nitrification (with oxygen) and denitrification (without or oxygen-limited).  In the nitrification pathway, the bacteria play an important role for agriculture and aquaculture, taking ammonia and in the presence of oxygen (oxidation) to nitrate (two-step process).  In the denitrification pathway, oxygen is limited or absent and the bacteria take nitrate and release nitrogen gas.  This is opposite the agricultural use and why oxygen soil pore levels are so important to agriculture and soils flooded by water or compacted soils with limited pore space avoided.  (This system is being built into many wastewater treatment systems to remove nitrogen, mostly nitrate from wastewater streams.).  A different type of bacteria are heterotrophs and can consume ammonia compounds directly from the water.  Heterotrophic bacteria thrive in organic solids while those that produce nitrate on surfaces and the oyster shell filter media, the nitrosomonas and the nitrobacters; however, all three types need oxygen.  In low-oxygen events, organisms (fish) are threatened by low oxygen so also the nitrogen filters.  If the filter is killed, most often the oxygen-requiring life is killed as well but we intervene before this happens.  We add oxygen, keep the water cooler or flush the system.  In large ecosystems, fish such as winter flounder, a "bottom" fish are often first to die.  Most aquaculture systems try to favor nitrobacters and nitrosomonas by keeping biosolids at low levels, requiring clean filter media or filters to remove unwanted solids and proteins.  Oyster shells not tightly packed create space (voids) that allow solids to settle and, if blocked, some sulfides that turn the shells black.  Oyster shell also acts to control acid pH (calcium carbonate levels).  It is an important reminder that seawater contains sulfate, an oxygen source compound for SRB (sulfate-reducing bacteria); they do not require elemental oxygen but release hydrogen sulfide highly toxic to fish and shellfish.  In seawater they will never face a "true" oxygen shortage as they utilize abundant sulfate as an oxygen source.

Oyster shells or other fixed media filters once submerged need periodic replacement/changes from solids.  Some of the early salmon shell biofilters at the University of Rhode Island developed by Meade (1973; 1978) were modified by Visel 1981-1983 for lobster crab display systems (See Gravity Fed Self Regularly Bio-Suspended Solids Pillow Filter For Crabs and Lobster Tanks, Visel, 1988).

Autotrophic denitrifying bacteria do influence sulfide formation in systems with seawater and dissolved sulfate and help prevent toxic conditions (Denitrification in Recirculating Systems: Theory and Applications, Rijn Jvan, 2006).   So much of the inshore waters productive for fish and shellfish (aquaculture) can be damaged by high carbon organic inputs with warm seawater.  In hot conditions, sulfide can reach such levels as to cause "dead bottoms."  These are the areas in which eelgrass dies.  It is also where adult bay scallops die in massive "kills."

Four Decades of Eelgrass Research – 1982 to 2022

One of the problems of fishery management is that species are always thought to be stable, and if not, it is the fault of human actions.  This is sometimes true but most often merely reflects natural conditions.  In 2022, I wrote about a city in Mexico Teotihuacan, which was discovered empty in the 1400's by the Aztec empire.  Here was a city not destroyed by fire or war but for some reason abandoned.  For decades, researchers wondered about the reasons.  Several concepts were put forward, such as disease, war, a rebellion against a ruling body or ruler, religious conflict or civil collapse.  Only in rare instances a reason was put forward as to climate.  If the climate had changed, then the conditions for survival also could be changed.  These changes can both be sudden and dramatic.  I concluded that perhaps the last days of Teotihuacan were just "days without rain" (See IMEP # #111: Climate and World Food Demands Increase Seafood Roles, posted on The Blue Crab Forum^TM). 

In today's media, climate change is mentioned as a new event or condition.  This is not the case – long periods or rain (floods) or drought (fire) often have a background of human population changes.  We attempt to categorize these events as natural resource events but rarely involve demographic change as a result.  When one looks at the abandonment of Greenland by the Danes after about 500 years (985 to 1500) and compare it to a shorter growing season, you could come to a climate conclusion. Perhaps, the first settlements happened when Greenland was, in fact, green and warm soil so that (traditional) terrestrial agriculture could be practiced.  Perhaps that is why the first settlements existed for as long as they did.  Now, look at what a gradual cooling could do to the growing season.  A series of early freezes and late spring frosts would doom those societies dependent upon agricultural harvests.  In time, these villages or cities are abandoned.  A change in climate could shift temperature and rainfall recorded in cores of soil horizons as changes in plant species from pollen.

That is the problem (my view, T. Visel) with large segments of eelgrass grant research – one observation or series of observations in short time periods are held as a constant positive habitat value, which is incorrect.  Habitat conditions, however, never remain the same – they change with the climate.  In the late 1880's and 1890's, the climate was warm even at times "hot" in New England.  It is at this time that oyster farmers recorded the expansion of eelgrass habitats.   These negative oyster culture interactions are found in numerous shellfish industry bulletins and monographs.  Around 1915, eelgrass is thought to have reached its largest habitat extent or coverage in the middle Atlantic to southern New England.  After four decades, the climate cooled and then turned sharply colder 1924 to 1928. 

In the late 1920's, eelgrass mold disease appears then grew virulent in the compost that built up in the previous warm period 1880 to 1920.  Eelgrass soil molds kept to cooler regions that were also swept by storms.  It is here that eelgrass underwent a natural soil renewal process and deep deposits of high carbon composts did not accumulate like those in protected shallow coves and bays.  It is in the shallows away from high energy storms that the eelgrass mold, Labyrinthula zosterae, was so deadly.  As eelgrass died off, bird naturalists and duck hunters were the first ones to report it.  The first concerns came from the duck hunters, who complained that the taste of Brant, a popular waterfowl hunter species, had changed.  Brant fed almost exclusively upon eelgrass, giving its flesh a "grain fed" flavor.  When eelgrass died off, Brant faced starvation and many switched to consuming a macroalgae species, Ulva lactuca, or sea lettuce.  This caused the flesh of Brant to taste bitter and some other words I can't use here.  Very quickly, Brant lost its taste and hunter appeal (See Waterfowl Tomorrow, United States Department of Interior Fish and Wildlife Service, 1964).  As eelgrass died off, New England was hit with a series of powerful hurricanes beginning in 1938 as the climate turned much colder.  These storms moved sand and bits of bivalve shell as a hydraulic wash with low density fractions shell coming to the surface.  This had a natural soil liming pH moderation impact.

Fines were flushed out much like the backwash feature of a residential bead filter for a domestic pool.  These storm-driven sands or "new sand" in the fisheries literature now set heavily with the hard shell clam Mercenaria mercenaria.  As these great sets matured,  production increased.  It is at this time that eelgrass came back and in industry reports soon overwhelmed quahog beds.  This decline in clam habitat reached its maximum extent in the early 1960's.  The Rhode Island hard clam (quahog) production figures clearly show this increase after 1938.  As the New England climate moderated in the late 1970's, eelgrass started to die off again fifty years after the last dieoff.  It followed the same habitat reversal in the hot 1990's as it did in the hot 1890's, completing a 100 year cycle.  Bottom disturbance (storm energy) categorized as "bad" may, in fact, help eelgrass meadows to self-seed.  This theory is rarely presented or mentioned in the recent eelgrass literature.  There is a huge divide in explanations for eelgrass decline – one, a natural habitat condition brought about by climate, the second (and most popular condition) is that declines were caused by human actions including beach use, motor boats, docks, owning coastal homes, moorings and periodic dredging. 

The problem is most of the research that supports the latter is funded by regulatory or non-profit organizations that have a protection or conservation advocacy.  The law of habitat succession appears to be forgotten. Why? – my view, Tim Visel.
 

Appendix #1

 

Recent Marine Sediments - A Symposium

 

Edited by

PARKER D. TRASK

U.S. GEOLOGICAL SURVEY, WASHINGTON, D.C.

 

PUBLISHED BY

THE AMERICAN ASSOCIATION OF PETROLEUM GEOLOGISTS

TULSA, OKLAHOMA, U.S.A.

___________________

 

LONDON, THOMAS MURBY & CO., I, FLEET LANE, E.C. 4

1939 - 1955

 

OCCURRENCE AND ACTIVITY OF BACTERIA

IN MARINE SEDIMENTS

 

CLAUDE E. ZoBELL

Scripps Institution of Oceanography, University of California, La Jolla, California

 

ABSTRACT

 

Aerobic as well as anaerobic bacteria are found in marine bottom deposits. They are most abundant in the topmost few centimeters of sediment below which both types of bacteria decrease in number with depth. A statistical treatment of the data on their vertical distribution suggests that aerobes are active to a depth of only 5-10 centimeters whereas anaerobes are active to depths of 40-60 centimeters below which they seem to be slowly dying off. However, microbiological processes may continue at considerably greater depths owing to the activity of the bacterial enzymes that accumulate in the sediments. The organic content is the chief factor which influences the number and kinds of bacteria found in sediments.
 
Bacteria lower the oxidation-reduction (O/R) potential of the sediments. Vertical sections reveal that the reducing intensity of the sediments increases with depth but the muds have the greatest reducing capacity near the surface. Three different types of oxygen absorption by the reduced muds are described, namely, chemical, enzymatic, and respiratory.
 
Bacteria that decompose or transform proteins, lipins, cellulose, starch, chitin and other organic complexes occur in marine sediments. These bacteria tend to reduce the organic matter content of the sediments to a state of composition more closely resembling petroleum although methane is the only hydrocarbon known to be produced by the bacteria. The precipitation or solution of calcium carbonate as well as certain other minerals is influenced by microbiological processes that affect the hydrogen-ion concentration. Other bacterial processes influence the sulphur cycle and the state of iron in the sediments. The possible role of bacteria in the genesis of petroleum is discussed.
 

DECOMPOSITION CAUSED BY BACTERIA

 
Various physiological or biochemical types of bacteria have been demonstrated in the sediments that are capable of attacking most kinds of organic matter present in the sea. The rate and end-products of decomposition of the organic matter depend upon environmental conditions and the types of bacteria that are present. Waksman and Carey (49) have shown that diatoms, Fucus, alginic acid, copepods and other marine materials are utilized by bacteria with the rapid consumption of oxygen and the production of carbon dioxide and ammonia. More resistant fractions of marine plants and animals such as lignins hemicellulose-protein complexes may be only partially decomposed to give rise to marine humus (50).
 
Approximately one-fourth of the bacteria isolated from marine sediments are actively proteolytic (18,56) as indicated by their ability to attack proteinaceous materials and in so doing liberate ammonia, hydrogen sulphide and carbon dioxide. Presumably the topmost layer of sediment is the zone of greatest proteolytic activity below which there is a gradual, but not very appreciable, decrease in the nitrogen content of the sediments (30). According to Trask (45) amino acids and simple proteins constitute a very minor part of the organic-matter content. Hecht (23) reports that most simple proteins are completely decomposed even under anaerobic conditions and are not converted into adipocere. He records that about 90 percent of the nitrogen content sediments is due to chitin. Chitinoclastic bacteria are widely distributed (57) throughout the sea but chitin is only slowly attacked by bacteria even in the presence of oxygen and it may be more resistant under anaerobic conditions.
 
Most simple carbohydrates are readily decomposed (54) by the bacteria that occur in bottom sediments. Under aerobic conditions the end-products of the fermentation of carbohydrates are chiefly carbon dioxide and water. In the absence of oxygen, carbohydrates may be attacked and thus yield organic acids, methane, carbon dioxide, hydrogen and other products. Buswell and Boruff (9) noted the production of acetic, butyric and lactic acids, alcohol, methane, hydrogen, and carbon dioxide from the bacterial fermentation of cellulose under anaerobic conditions. Several types of cellulose-decomposing bacteria (48, 49, 51) have been isolated from bottom deposits but very little is known concerning their metabolism. The fact (45, 46) that less than 1 percent of the total organic-matter content of recent sediments is carbohydrate, whereas ancient sediments contain none, is indicative of the vulnerability of this class of compounds to bacterial attack. However, much remains to be done to ascertain the end-products of the reactions.
 
Perhaps bacteria have a greater influence than any other form of life on the hydrogen-ion concentration and O/R potential of sediments; properties that in turn tend to modify both the chemical composition and physical characteristics of the sediments. They may deplete the oxygen as noted above, they may liberate nitrogen from nitrites or nitrates and they may produce carbon dioxide, carbon monoxide and methane in appreciable amounts.
 

 

 

Appendix #2

 

Land Utilization of Dredged Materials

A Subaqueous Soil Interpretation

April 2018

United State Department of Agriculture

Natural Resources Conservation Service

 

Introduction
"Sulfidization, or the accumulation of sulfides, is an important soil-forming process in estuarine and marine soils (Fanning and Fanning, 1989).  In these settings, sulfate, the second most common anion in seawater, is reduced to sulfide through the metabolism of sulfate-reducing bacteria in the subsurface anaerobic soil (Jorgensen, 1977; Day et al., 1989).
Sulfide is most often trapped in the sediment by binding with metal ions, such as iron (Fe) (Jorgensen, 1977).  The sulfide content of soils is important when considering marine construction, dredging, and beach and dune nourishment projects.  If sulfide-bearing subaqueous soils are dredged and placed in a subaerial environment, sulfides will oxidize, creating sulfuric acid, drastically lowering soil pH (to a pH of less than 4), and resulting in acid sulfate soils (Fanning and Fanning, 1989).
Acid sulfate soils may persist for a number or years and are uninhabitable to plants and animals.
 

Appendix #3

NOAA Fisheries Milford Aquaculture Seminar

Do We Have The Correct Scallop Grass? A Habitat History for Eelgrass Zostera Marina in New England Coastal Waters

Reference Section for The Milford Paper – February 2012

Comments about Eelgrass and Shellfish during The Great Heat

1880-1920

 
Poquonock River, Groton, Connecticut
Notes on the Oyster Fishery of Connecticut by J. W. Collins, U.S. Fish Commission Bulletin Vol 1X 1889 22 - Notes on the Oyster Fishery of Connecticut pg. 477-26 the Poquonock method. "The Poquonock oyster on driven brush caught and grew oysters but eelgrass caught among the brush spot collectors stopped the tides and the river "fouled." There are several reasons why it has not proved entirely successful among which may be the collection of large quantities of eelgrass about the flats at the mouth of the stream, causing stagnation of the water and producing such conditions that Board of Health of the town has caused the bushes (spat collectors) to be pulled up and destroyed."

Connecticut Injury to Oysters – Known Causes – J. W. Collins
39 – Stagnant Water - "Injury to oysters by stagnant water is comparatively rare. The only place where Mr. Stevenson found this had occurred was on the Poquonock River in the Town of Groton. There the current is checked by eelgrass and during hot weather, it sometimes becomes peculiarly offensive and causes the death of the oysters within the limits of the Stagnant Water." Pg. 483.

In the time of The Great Heat, bay scallops in the Poquonock River did not exist but oyster sets were tremendous as waters cooled and energy increased the Poquonock River would become Connecticut's second largest producer of bay scallops – in the 1940s – 1950s thousands of bushels of bay scallops would be harvested here and oyster sets become rare or nonexistent and the river witnessed a familiar exchange between colder and warmer tolerant species.
 

Appendix #4

 

EPA Long Island Sound Study Research Grant Program

2020 Research Project Descriptions

Projects will take place from 2021 to 2023

Improving Eelgrass Restoration Success by Manipulating the Sediment Iron Cycle

 

Investigators: Craig Tobias and Jamie Vaudrey, University of Connecticut; Chris Pickerell, Cornell Cooperative Extension
 Grant Award: $323,404, plus $161,786 in matching funds
"While many Long Island Sound embayments now have improved water quality that should make them suitable for eelgrass restoration, there is a difference between the acreage of habitat that could theoretically support eelgrass and where it has actually regrown or been restored successfully. Sediment is a key component that may have been overlooked and is a potentially limiting factor for eelgrass restoration efforts to move forward, which is a key goal of the Long Island Sound Comprehensive Conservation and Management Plan. To develop a new restoration management framework, this project will map sediment sulfide and iron gradients in relic eelgrass beds in the Niantic River Estuary, and correlate sulfide concentrations to other sediment variables to establish easy-to-measure proxies for sulfide for use in evaluation of potential eelgrass restoration. The project will then conduct experiments to test the effect of adding iron-oxide pellets, a cost-effective tool, to sediments on porewater sulfide and solid phase iron-sulfide mineral content. This method of iron amendments could potentially be easily integrated into existing restoration techniques."

Appendix #5

 

A Review of Fisheries Histories For Natural Oyster Populations in Tidal Rivers

Adult Education Program – Fourth Annual Meeting of CT Shellfish Commissions January 12, 2008

 By Timothy C. Visel, Coordinator

The Sound School Regional Vocational Aquaculture Center

December 2007

 
John "Clint" Hammond, an oyster grower of Chatham, Massachusetts, described a similar situation in which both sea lettuce and eelgrass grew on top of his planted oysters. It got so bad that he hired two high school students to tow a section of page fence over his planted oysters in an effort to cut it off. He said it worked very well but needed to be done at least twice before the winter time. Mr. Ronzo had seen the seaweed increase also. When we saw him again, he was still trying to get answers from the town about Route 95 and Route 1 storm water (street water) discharges. He continued to be convinced that the problems in the lower river were caused by watershed changes up river. He also felt excess nutrients were finding their way into the watershed since he had never seen so much seaweed/sea lettuce as now. He remembered seeing "a patch" now and then while blue crabbing; he would look for soft shell crabs under it, but it was nothing like it was today. To him, it seemed as if the entire river bottom from bank to bank was covered with it.
My experience on Cape Cod, with Green Pond, a small coastal salt pond, had the same type of sea lettuce growth. In 1981, it was undergoing intense eutrophication. The sea lettuce got so thick and oxygen levels got so low that the blue crabs left the pond by walking along the shore. Green Pond became anoxic one August afternoon and killed many winter flounder. Just a few days before, many of the residents along Green Pond had complained to the Cape Cod Extension Service in Barnstable (where I was employed) about a rotten egg, hydrogen sulfide smell coming from the pond. It was a warning that the pond was about to go anoxic. Unfortunately, Mr. Ronzo reported the same type of smell several times in the morning on calm days from the Oyster River (Old Saybrook, CT).  To him, the "marsh gas" smell was becoming more frequent.

Jack Milkofsky wanted to see if a similar device or devices which Mr. Hammond had used on Cape Cod to "battle the seaweeds" could be used here. The Old Saybrook Shellfish Commission would purchase the needed materials. Two types of "cultivators" were built, one of 4 foot wide by 4 foot long section of collapsible "page" type metal fencing that was attached between two one-inch diameter black iron water pipes; a bridle towing point was attached. After a quick couple of tows, it was necessary to add a second section of pipe to keep the fence on the bottom and in contact with the bottom. The sea lettuce did get pulled off the oysters, but the "cultivator" had to be frequently cleaned. The fence itself turned into a green carpet of sea lettuce and tended to come off the bottom. A second cultivator was built two weeks later out of chain mail, the same rings and connectors as the bottom bag of the hand-hauled seed oyster dredge. Long chains of rings (8 feet) were connected to two one-inch diameter black iron pipes. The pipes need to be drilled to accept eye bolts at regular intervals. The second cultivator was tried in the same section of the River between Pelton Avenue and Waterbury Avenue with Mr. Ronzo watching. This cultivator worked better. The spaces between the rings tended to pass limbs, sticks and leaves as well as pull off the blades of sea lettuce. Once detached, the sea lettuce tended to float between the rings and be carried by the ebb tide. (Note: Most cultivating is done on the ebb time. We noticed that fish tended to "flee" when the noise of the outboard and rig approached; they returned quickly when the operation ceased.) This process tends to wash the oysters of silt, muck and partially decayed leaves. This material, when cast down river, seemed to attract large numbers of sand shrimp. It would be helpful to know the responses of bottom organisms with such bottom cultivation in the field with oyster shells. After a few tows, we waited for the water to clear and dropped the hand-hauled seed oyster dredge. Although the dredge quickly loaded with sea lettuce, it was loose sea lettuce, so Mr. Milkosky and I felt the second cultivator was more effective. At the end of the tide cycle, we observed rolls of sea lettuce near the banks.

At the end of the second trial, he was going to contact some local commercial fishermen to see if he could enlist someone to help cultivate the beds so the young oysters could mature.

That was the last time I was on the Oyster River and spoke with Anthony Ronzo. When we last spoke at the boat ramp off Pelton Avenue, he was still pursuing the storm water problem. By that time, the Old Saybrook Shellfish Commission/Health Dept. had suffered some serious budget cuts, and Mr. Milkofsky stated that the problem storm water and bacterial counts was seen to be beyond the scope of his current assignments.

Old Saybrook Shellfish Commission Cultivators (July 1985) materials for Chain Mail purchased from Wilcox Marine Supply, Stonington, CT.  
The "Page" fence type cultivators were once used, John C. Hammond, Oyster River Chatham, Massachusetts.