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Author Topic: Eelgrass Blue Crabs Lobsters and Vibrio Bacteria EC #11 - Tim Visel  (Read 1411 times)
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« on: April 28, 2016, 07:30:03 PM »

Eelgrass Blue Crabs Lobsters and Vibrio Bacteria EC #11
The Blue Crab Forum™ Environment and Conservation
March 10, 2016
A Capstone Proposal for FFA Non Experimental SAE
Tim Visel, The Sound School Regional Vocational Aquaculture Center
60 South Water Street
New Haven, CT  06519

{The views expressed here do not reflect the Citizens Advisory Committee nor Habitat Working Group of the EPA Long Island Sound Study.  On February 16, 2016 I have asked resource management agencies to recognize Sapropel as a distinct habitat type.  This is the viewpoint of Tim Visel}.

Capstone Questions –

1)   Do we have an accurate understanding of the Sulfur Cycle’s relationship to the Nitrogen Cycle in Long Island Sound?

2)   Can the rise of the Blue Crab population be traced to the return of the Sulfur Cycle in shallow habitats?

3)   Has cooler winters and stronger storms changed estuarine habitat quality for both Eelgrass and Blue Crabs?

Connecticut Career and Technical Education Performance Standards
Aquaculture #6, #9
Natural Resources #4, #7, #9, #14

A note from Tim Visel

This is part one of a two part report – the second report titled Blue Crabs and Marine Bacteria should be finished by July 2016 as # EC 12.

With the Connecticut 2015 blue crab season so different from the one in 2010 temperature and habitat quality blue crab abundance questions need some investigation.  Habitats which at one time seemed to contain so many blue crabs here in Connecticut last year appeared empty?  The truth is we really do not know much about the biological and chemical conditions of the habitats in which blue crabs live, the marine compost.  To gather as much information as possible I have looked into a land compost equivalent – salt marsh and fresh water peat.  Researchers a half century ago were looking at peat, its biochemistry, and bacterial make up.

They were also talking about Sapropel and Saprophytes those organisms that lived among the dead and the by products of bacterial decay in low or no oxygen conditions.  From the Practical Encyclopedia of Gardening Norman Taylor editor Halcyon House Garden City of New York, 1942, pg 711 gives definition to the term “Saprophyte” a plant that lives on the dead remains of other plants.”  They get their food with the aid of various microscopic organisms of decay (fungi and bacteria) which helps to decompose the material upon which saprophytes live….  The whole subject of Saprophytism, while of absorbing interest to the botanists, really lies outside the scope of gardening.” 

Saprophytism however did have a role in the great eelgrass pandemic of 1928 to 1936 which saw eelgrass populations decline across the globe from a fungus – a saprophyte.  While blue crabs are associated with warmer temperatures to our south blue crabs seemed to be able to survive many mild winters and even develop a sponge here, a reproductive capacity I doubled once existed.  I no longer have doubts about that now.  The series of mild winters and very hot summers saw blue crabs in large numbers here enter that reproductive stage.  A series of colder winters after 2011 has been linked to the recent collapse of the blue crab population, which tells a very easy explanation but for habitat quality we need to know more about what happens when crabs hibernate – my view.  We need to know more about eelgrass/sapropel meadows in heat and in very cold.  In terrestrial terms blue crabs hibernate in compost – a collection of dead and decaying organic matter that in times of heat is a part of the sulfur cycle as on land.

The cycle of blue crabs may have direct and indirect association to the sulfur cycle itself which has both a temperature and energy connection.  A series of mild winters and very hot summers from 1998 to 2011 was very good for Connecticut blue crabbers – for over a decade catches went up but did recent cold winters change that?  I believe that the cold winters altered habitats as well as altered the ability of the Megalops stage to survive here and that changed at times to several  unfavorable habitat conditions – wind direction, temperature and winter kill.

It was more than temperature change but chemical and biological changes in the habitats themselves.  A review of peat deposits may provide important clues to the different habitat conditions for blue crabs when temperatures quickly change.  These changes may provide important clues to the reasons for the rise and fall of blue crab populations. 

Students interested in this as a Capstone Project please see Tim Visel in the Aquaculture Office.

Environment and Conservation – The Blue Crab Forum™ - Bacteria Nitrogen Series

I want to thank the Blue Crab Forum™ for allowing me to post in a new thread – Environment and Conservation and also Connecticut Fish Talk for reposting these reports. This is my eleventh report about bacteria and nitrogen cycles.  Coastal habitats once praised for valuable habitat services are impacted by bacteria and at times become nature’s killing fields, eliminating critical nursery and spawning grounds for many inshore fish and shellfish species. Coastal fishers often observe these events, mats of bottom bacteria, chocolate or purple waters, brown tides, blue crab jubilees or just fish kills. Beyond these public events bacteria and nitrogen change the habitat qualities that we recognize today as “good” onto something that is “bad” for inshore fish and shellfishing.  Out of sight and rarely discussed, these conflicting bacteria strains have important implications for estuarine health and seafood production worldwide. 

   #11 Eelgrass, Blue Crabs, lobsters and Vibrio Bacteria - March 2016

   #10 Oxygen and Sulfur Reducing Bacteria Questions – Dec 17th 2015

   #9 Nitrogen and Eelgrass Habitat Questions 11/18/2015

   #8 Natural Nitrogen Bacteria Filter Systems 10/20/2015

   #7 Salt Marshes a Climate Bacterial Battlefield 9/10/2015

   #6 Bacteria Disease and Warm Water Concerns 7/23/2015

   #5 Nitrogen, Inshore Habitats and Climate Change 1/12/2015

#4 Black Mayonnaise Impacts to Blue Crabs and Oysters 1972 to Present   

#3 A Caution Regarding Black Mayonnaise Habitats 10/2/2014

#2 Black Mayonnaise, Leaves and Blue Crab Habitats 9/30/2014

#1 What About Sapropel and the Conowingo Dam? 9/29/14

Fishers should follow this bacterial conflict as more and more information comes in regarding habitat quality and important recreational fisheries such as striped bass, winter flounder and blue crabs or lobster habitats are subject to bacterial impacts. It is also important that shallow water fishers be aware that sulfur bacteria contain a series of antibiotic resistant strains first identified in “Contaminate Effects On Biota of the New York Bight“ by Joel, O’Connor, NOAA (1976).  Soft organics with bacteria do pose risks to fishers and bathers – coastal bacteria benthic monitoring programs are needed. – My View.


The 2002 to 2012 decade brought increasing water temperatures to Long Island Sound.  Shallow seas and bays give us a first look at what climate change can do to these habitats.  At first the heat vanquished our lobsters followed by increasing populations of the blue crabs in New Haven Harbor.  This was in stark contrast to New Haven Harbor surveys of the 1970s during a much colder period. (Thanks to Paula Daddio an aquaculture science educator here who found these 1970 era New Haven Harbor surveys).  (Summary report 1970-1977 New Haven Harbor Ecological studies 1979 Normandeau Associates, Inc. Prepared for United Illuminating Company New Haven, CT – 433 pages 13-33).  Then blue crabs were scarce here (New Haven Harbor) lobsters were very abundant at times almost to the junction of the Mill and Quinnipiac Rivers (Normandeau Associates Inc., 1979).  That would all change in the 2000’s.  Otter trawl surveys from our research vessel Island Rover with Jack Cardello, John Walsh and Robert Boulware brought up small trawls with numerous blue crabs – lobsters were now scarce in New Haven Harbor.  The blue crab population that surged in the 2000’s would end in 2013.  Cooler winters are now thought to have diminished blue crab populations in Long Island Sound and ended perhaps recruitment from the megalops stage.

The New Haven Harbor Ecological studies conducted for United Illuminating Company in the 1970s  (Normandeau Associates, Inc 1979) gives a picture of the end of the colder Northeast Atlantic Oscillation (NAO) of the 1970s.  These surveys detail what was “present” in New Haven Harbor and provide indications of habitat quality.  Surveys of the harbor then found lobsters to be seasonal visitors – prevalent in the colder months and some years surprisingly abundant.  Blue crabs were scarce in New Haven Harbor during this period and were often not listed – a few surveys years only mention one or two blue crabs being observed at all.  During this time the most prevalent crab in New Haven Harbor was the rock crab (1979 Normandeau Associates pg B-14) rock crabs prefer cooler temperatures.  (Rock crabs can in cooler periods become very abundant).

By 1979 New Haven Harbor was beginning to warm coming off its most negative NAO years in the 1950s and 1960s but is colder water habitats still reflected fish and shellfish that thrived in colder waters.  They “hung on” past peak habitat conditions.  As reproductive capacity and survival changed so did species prevalence.  Long Island Sound surveys in the 1950s (Richards 1959) found that in 1954 and 1955 tautog (Blackfish) was one of the top 5 Long Island Sound species by the amount of water column fish eggs but by 1976 it didn’t make the list.  Rainbow smelt Osmerus mordax was also found in New Haven Harbor in the 1970s (Native Americans sometimes referenced it as the “ice fish”).  A small otter trawl survey in 1973 sometimes sampled over 1,000 smelt per tow (Normandeau Associates 1979 11-16) in New Haven Harbor but had dropped to only 25 to 70 per tow or less by 1977.  Today such smelt in Connecticut can be described as rare.  After a long warm to hot period our winters turned sharply cooler after 2011.  Will the smelt return to Connecticut and New Haven Harbor – that remains to be seen but if the cold continues the “ice fish” may return to our waters. 

Colder periods however have not been associated with higher blue crab populations – leaving opportunities to explore past habitat and climate changes with those long ago shell middens here in Connecticut.  The return of the largely positive NAO phase (usually warmer summers and less severe winters in New England) had some seafood species take off in the 1990s – while others declined.  The increase in the blue crab population here the last decade was to me outstanding.  I had not experienced such blue crab populations in the 1960s but that was very different here in the 2004 to 2011 years.  Blue crabs soared to at times almost unbelievable catch levels.  When Jon Morrison of the USGS stepped onto the Essex Town Dock in mid August of 2010 to check instruments one of the peak catch rates occurred then – 4 baited lines were yielding up to 100 blue crabs per hour – some family catches were above that level.       

In July 2011 evidence from Connecticut Blue Crabbers (The Search for Megalops reports) indicated three distinct waves of blue crabs as small blue crabs were now reported being in dense patches (waves) from New Haven to Greenwich (The Blue Crab Forum™ - Northeast Crabbing Resources.  The Search for Megalops Report #8, July 11, 2011).  As the heat continued, adult blue crab populations now surged in Connecticut but so did Vibrio bacteria.  (Vibrio Infections and Surveillance In Maryland, 202-2008 Erin H. Jones et al 2013 Public Health Reports – Nov-Dec Volume 128, Maryland Department of Health and Mental Hygiene, Baltimore, MD).  Connecticut faced a Vibrio shellfish closure in 2012 as the continued heat brought forth a unwelcome guest Vibrio Bacteria.  Organic deposits in the shallow coves are suspected of helping this Vibrio Bacteria grow and as fishers noticed this blue-black material (Sapropel) others overseas involved in estuarine research noticed it as well.  About 70 research papers have now looked at Vibrio bacteria and it connection to warm oxygen deficient organic deposits.  (Vibrio Abundance in Tidal Creeks Sediment/Water Dynamics Marine English UNC Institute of Marine Sciences 2012).  Eelgrass by its natural organic binding holding characteristics helps Vibrio grow – many research papers have found this sulfur reducing bacteria series under eelgrass meadows.  (Draft Genome Sequences of Two Vibrio Splendidus Strains Isolated From Seagrass Sediment Ruth D. Lee et al - Jan/Feb 2016 Vol 4 #1 Genome Announcement – UC Davis Bodega Marine Laboratory Bodega Bay California (Zostera marina) – “New Marine Nitrogen – Fixing Bacteria Isolated From An Eelgrass (Zostera marina) Bed.”  Wang Yang Scheh et al.  Canadian Journal of Microbiology 1988 34/7 pg 886-890.  Eelgrass bed Abaratusubo Inlet Kanagowa Prefecture – Japan.  Ocean Research Institute University of Tokyo.  Sediment and Vegetation As Reservoirs Of Vibrio vulnificus in the Tampa Bay Estuary and Gulf of Mexico.  Applied Environmental Microbiology 2015 April – Chase et al American Society for Microbiology).  Some species of Vibrio bacteria appear to be only related to eelgrass meadows itself.  (Bacterial Interactions in the Rhizophere of Seagrass Communities In Shallow Coastal Lagoons, Journal Applied Microbiology 1998 Dec University of Dundee UK.  New Vibrio species are being found and overseas research papers continue to become available from this 2002-2012 period that highlight Vibrio research.  (Climate Change Influences on Marine Infectious Diseases.  Implications for Management and Society Annual Review of Marine Science, Vol 6, pgs 249-277 January 2014, Colleen A. Burge et al Cornell University Ithaca, New York). 

As Long Island Sound waters warmed habitats changed as a shift towards the sulfur cycle happened.  When then occurred Vibrio bacteria is now thought to have increased in sulfur containing Sapropel.

Vibrio bacteria have a direct connection to the sulfur cycle and warming – hot weather can return the sulfur cycle to our marshes and tidal flats turning them against the seafood we appreciate.  (The Blue Crab Forum™ Environment and Conservation #7, September 10, 2015 Salt Marshes – A Climate Change Bacterial Battlefield).

As seafood abundance has direct connections to habitat quality – a habitat change proceeds a change in species, especially when the sulfur cycle returns.  These changes will be reflected in fisheries catch statistics and later regulatory changes.

The cycle of eelgrass does seem to be an indicator for the sulfur cycle.  Cold periods and moderate amounts of energy eelgrass now thrives and is the home for both blue crab and in northern areas lobster megalops.  This is the “clean and green” eelgrass that I mention frequently however in high heat eelgrass helps the sulfur cycle return until it is also killed by it.  This is the high heat low energy eelgrass or the “brown and furry” meadows under which it appears Vibrio now thrives. 

There is no “tool kit” to reverse this high heat sulfur cycle – the rise and fall of eelgrass meadows does have a temperature and energy connection, eelgrass now it appears has a direct role in Vibrio populations as well.  (Sulphate Reduction in the Root Zone of The Seagrass Zostera, noltii On The Intertidal Flats Of A Coastal Lagoon (Accachon France Mai Faurshoou Isaksen, Kai Finster University of Aarhus – Aarhus, Denmark 1996 Marine Ecology Process Series Vol 137 pg 187-194). 

The thick growths of eelgrass in high heat helps the sulfur cycle return and when it does it kills the seafood we seek.  In colder times eelgrass helps seafood recover in a long cycle of habitat change that may be a century in length.  We may learn that in our area the cold clean and green eelgrass helps our lobster megalops while the brown and furry eelgrass helped kill it.  In time we may find that blue crabs become prevalent here at a habitat point in which the sulfur cycle “wins.”

I respond to all emails at [email protected]   


During the colder more energy filled negative NAO in the 1950s, the oxygen reduction of organic matter was so fast and efficient researchers at one time felt that Long Island Sound was nitrogen limited (Riley 1959). Terrestrial composters often turn the compost to mix in oxygen – to assist same “quick” reduction composting process but with different bacteria.  In the garden literature of 1940s the mention of “stirring” a compost is mentioned and was also part of the oyster aquaculture nomenclature as setting beds were frequently stirred (See New Haven’s Lost Oyster Beds Greenfest June 4-6 2010 The Sound School) to keep organics off.  This is a section from “The Practical Encyclopedia of Gardening edited by Norman Taylor (1936) reprinted in 1942 by Houghton Mifflin company – The Riverside Press Cambridge Massachusetts, pg 165. 

“Where a large amount of compost is to be made it is advisable to make the pile long and narrow.  This facilitates mixing or “stirring” the compost, a necessary procedure, which aids the composition and mellows the mixture.  It may be used to fertilize flower beds, trees, shrubs, etc and is invaluable as a top dressing for lawns.” 

It is strong storms that turns the marine compost in heat Sapropel or in cold sulfide rich organic mater deposits.  The colder storm filled NAO had another aspect, particulate organic matter dominated phytoplankton surveys.  The energy from these storms kept organics from setting and they soon entered the water column.  Leaves did not accumulate in slow waters, storms kept these organics “in motion” and present in the water column.  But researchers during this period did not include long term temperature changes from the 1890s and the 1950s which now saw some of the coldest temperatures in nearly a century.

Gordon A. Riley of the Bingham Oceanographic Laboratory in “Notes on Particulate Matter in Long Island Sound” (Oceanography of Long Island Sound volume 17, June 1959 Peabody Museum of Natural History Yale University, New Haven, CT USA) mentions that aspect in the 1950s.  In Long Island Sound plankton net surveys in 1956 and 1957 (Riley) found that “ a considerable fraction of the organic matter exists as detritus or as organisms that contain little or no chlorophyll.”  The cooler water contained more oxygen and the chlorophyll containing plankton quickly was recycled by oxygen requiring bacteria but the harder to digest organic matter such as leaf particles persisted longer.  In a period of heat, few storms meant organic matter now accumulated in the quiet back waters and oxygen being less available – chlorophyll would dominate plankton surveys.  In times of cold sufficient oxygen would allow oxygen requiring bacteria quickly to reduce carbohydrates and signal for rapid utilization rather than small production evidenced in net surveys of the 1950’s (Wangersky 1959).  But the extreme cold would limit bacterial growth and slow overall nutrient recycling. Even the bacterial connection to this rapid recycling was then questioned by Long Island Sound researchers – Wangersky 1959 – concludes “Elucidation of the relationship between dinoflagellates and marine bacteria is primarily a task for pure culture techniques in the laboratory.” 

Researchers surmised that organic matter was recycled differently and looked at temperature for possible explanations.  The relationship between bacterial growth and cold temperatures had of course long been known in agriculture (a painful food science lesson for farmers (milk) and the aquaculture industry (oysters) in the 1890s) today called “HACCP” (see Environment and Conservation #6 Bacteria Disease and Warm Waters Concerns posted July 23rd 2015 The Blue Crab Forum™.)  But the cold of negative NAO also altered the bacterial release of available nitrogen compounds – the “cold” nitrogen cycle didn’t work that well in very cold conditions.  When Long Island Sound cooled in the 1950s researchers noticed that plankton quickly mobilized nitrogen in the water column.  Several researchers surmised that the problem was slower oxidation (bacterial reduction).  In “Oceanography of Long Island Sound” a bulletin of the Bingham Oceanographic Collection Peabody Museum of Natural History – Yale University (June 1959 vol 17, article 1) New Haven, CT mentions this bacteria/oxidation question.  In an submission titled “The Nitrogen Cycle in Long Island Sound – Eugene Harris and Gorden A. Riley sampled nitrogen concentrations from October 1954 to June 1955 – in 5 stations in Long Island Sound – on page 60 is found this statement,

“The ultimate oxidation of ammonia to nitrate and nitrite was obvious only in autumn and winter.  The fact that little nitrate was present at other times does not prove that it was formed.  However the slowness of the oxidation as described by Von Brand et, al (1937) coupled with present evidence that phytoplankton readily utilized ammonia indicates that most of the ammonia was used before it could be oxidized.” 

And also that researcher during this period realized the role of benthic bacteria had in reducing organic matter freeing its nitrogen constituents for “reuse.”  The “stock” for nitrogen generation was the bottom organic matter (compost) itself as Harris continues to explain some times the apparent lack of nitrogen (Harris 1959) brackets indicate my insertions.

“The role of bacteria has not been examined directly, but it may be deducted from the foregoing discussion that they (Bacteria, T. Visel) supplied some 20% to 40% of the daily (Nitrogen, T. Visel) phytoplankton requirement.  Since their substrate (culture media – T. Visel) contained 85% of the nitrogen “stock” it would appear that their rate of turnover of nitrogen was an order of magnitude lower than animals.”

The lower bacterial reduction of organic matter freeing nitrogen was reduced in cold.  I wasn’t so much that cold water did not contain nitrogen compounds, it did, it was just that what was available was quickly put to use and plankton demands could not match supply.  Therefore, it was during the colder 1950s that Long Island Sound was occasionally termed “nitrogen limited.” – Researchers then were often looking at to short a picture to envision the entire “nitrogen movie.”  They were however able to observe and record spring blooms of plankton.  Colder water would slow bacterial growth and thus limiting nitrogen recycling leading to surges in plankton growth and then declines as available nitrogen was exhausted.

This cold “short” nitrogen oxygen cycle was the same one that Dr. Barbara Welsh mentioned during a 1985 workshop about Long Island Sound (see Environment/Conversation Post #10, December 17, 2015 on the Blue Crab Forum™).  When oxygen is sufficient easy to digest organic matter is quickly reduced (composted) the long nitrogen cycle occurs when oxygen is limiting (warm water) or the more slower compositing process.  Organics containing chlorophyll will show a sharp increase – the supply of oxygen directly influences what organic matter is reduced in the water column and how much chlorophyll is present.  In colder times with sufficient oxygen plankton with easy to digest cellulose/sugar structures were quickly reduced and recycled – by bacteria chlorophyll did not build up in the water column (and why to some extent very cold water is often clear, it naturally limits bacterial growth) colder water also means the oxygen requiring bacteria will dominate. 

It is the remarkable slowness of bacterial reduction of cellulose that has captured the attention of marine archeologists working in the Black Sea (also noted for some of the highest sulfide levels) here deep cool waters has slowed bacterial reduction so much that wood ships sunk thousands of years ago have been preserved in these cold sulfide rich waters.  Bottom water with no oxygen and cold has for most research findings caused cellulose digestion to stop – wood is not “eaten” or reduced in this environment.  National Geographic and Dr. Robert Ballard has discovered sailing ships 1,500 years old with the mast still standing.  Salt marshes and peat bogs with similar high sulfide low oxygen environments have been known to preserve similar artifacts.  Heat the water and Sapropel (compost) ammonia purges from this growing compost and feeds brown algal strains  – waters become cloudy and from reduced oxygen bacteria to quickly recycle these blooms when they die chlorophyll builds up.  Ultra violet light cannot penetrate “turbid” cloudy water so bacteria levels tend to rise.  The oxygen requiring bacteria are at first overwhelmed, add to the oxygen shortage and then die off - making room for the sulfur reducing bacteria.  Is this reversal seasonal, yes it is but imagine no winters, the sulfur reducing bacteria do not die back into the deeper organic sediments but live on the bottom surface – now perhaps all year long – organic matter builds up in heat and now provides a huge source of ammonia as organic deposits slowly burn into the Sulfur Cycle.  Vibrio bacteria can thrive in such conditions – as Connecticut experienced in 2012.

Long Island Sound has experienced this cycle and extended events or reversals of habitat quality before.  This is not new but recorded in the shell deposits left along our coast and in coastal coves.  This evidence provides how serious these warm and cold cycles can be to species abundance and how dangerous a continued warming will be in shallow waters habitats not only in Long Island Sound but worldwide. 

It is these habitats that will fail the seafood species that so much/many depend upon them.  In some historic shell deposits (middens) we may be able to see evidence of these past climate/seafood cycles.  An amazing account of this cycle evidence has been left by a 1950s historian named Mr. Harold Casner.  That account is found in the appendix 1. On Cape Cod a retired oyster grower was also watching the return of the Sulfur Cycle John C. Hammond which he termed “a reversal.”  (Mr. Casners review is perhaps the most significant for habitat reversals and the remains of Native Americans could provide key evidence as to species change from oysters (a warm period) to the quahog that flourishes in colder waters.  Native Americans may have left us the most important habitat history record – free of current discussions about climate change.  Several marine archeologists are reexamining shell middens to see if these species transitions can be in fact determined).

Peat Deposits May Provide Key Information

Records of past habitat conditions can also found in salt marsh cores and peat deposits.  The salt marshes are subject to the same composting processes as peat but we know more about peat because it has been a source of both fertilizer, and fuel.  Researchers in the 1930s and 1940s were exploring the biochemistry of peat deposits and bacterial reduction.  With or without the sulfur cycle the top layers of peat, reduction with the presence of oxygen in deep layers below the presence of sulfuric acid.  In many studies of peat researchers mention the ability of bacteria to break down cellulose as several New England studies in the 1930s and 1940s illustrates.  Waksman in 1942 (The Peats of New Jersey and Their Utilization) has several sections of the sulfur cycle in salt marshes and the issue of acidic Sapropel.  In a section titled “Utilization of Peat for Agricultural Purposes” Waksman 1942 mentions the production of sulfuric acid when Sapropel (Peat) is re exposed to oxygen and its field application.  Northern Agriculture Experiment stations once suggested to farmers to cut in oyster shell (northern areas lobster shell) to offset this “hurt full acidity from sulfuric acid” below is a section on pg 91 and a section on pg 110 as well (Waksman 1942).

“Among the various groups in microorganisms found in peat bogs, the occurrence of cellulose-decomposing bacteria, especially in low moor and in forest peats, is most characteristic.  Their presence is associated with the decomposition of the cellulose in these bogs.  The activities of the anaerobic bacteria is the lower layers result in the production from cellulose of various gases rich in methane and in hydrogen; in sulfur containing bogs, hydrogen sulfide is another characteristic product of decomposition.”

“The lowest layer of the peat and the surface layer of the underlying mineral soil may contain substances such as sulfate and sulfuric acid, which are highly toxic to plants.  These are rendered harmless by addition of lime.  Even when a peat is well supplied with lime in the surface layers, it may contain toxic substances below.  These ordinarily occur not only in undrained bogs, but may appear after drainage, as a result of the oxidation of the original iron sulfide or iron pyrites.  In contact with the oxygen of the air, these form iron sulfate and sulfuric acid, both of which are soluble in water and become toxic.  When these are mixed with lime, calcium sulfate is produced.”       

It is the process of bacterial reduction that holds many clues to estuarine habitat quality and habitat capacity to the fish and shellfish we call seafood.  The changes in bacterial composition gives us a unique climate change view – between warm and cold and oxygen and sulfur.

The Return of the Sulfur Cycle -

In most of my meetings with John Hammond on Cape Cod in the early 1980s eventually our conversations got onto the sulfur cycle.  On day in particular my “lesson” was a bit more direct than others “learn it” he said as he tossed a chapter on the “sulfur cycle” he had copied for me.  He was disappointed when I told him it (The Sulfur Cycle) wasn’t covered that much even in my oceanography coursework at the Florida Institute of Technology during my study there in 1973 (unfortunately the FIT campus at Jensen Beach was closed in 1986 and sadly also the campus Ralph S. Evinrude outboard engine repair laboratory).

I did look at this book section – 3 chapters one about Sulfur (13.1 Introduction).  Oxidation – Reduction Potentials (17) and Waterlogged Soils.  It was an older text “sulphur” instead of sulfur but on pg 303 has a figure labeled 13.1. The Sulphur Cycle In Nature (from Butlin 1952) showing Desupho Vibrio between sulphate and hydrogen sulphide.  I am certain I did not realize the significance of Desuphovibrio  in the chart then but explains why Mr. Hammond was studying the culture of rice and why also he used oyster shell in his pails of tomatoes to offset the acidity of Sapropel.  It also helps explain his knowledge of acid sulphate soils (1982).  This is a section about Acid Sulphate Soils (pg 304 sulphur) from the book sections he gave me in 1982 – it is just as appropriate today.

Acid Suphate Soils (Mr. Hammonds Book Chapters from 1982 citation source unknown)

“In many parts of the world an excess of inorganic sulphur compounds has proved toxic to plant growth or has induced toxicity.  Certain physiological diseases of rice, for example, have been traced to the presence of hydrogen sulphide in reduced layers of periodically submerged soils.  Waterlogged, sulphur-rich soil become extremely acid if allowed to dry owing to oxidation of sulphur.  Acid sulphate soils, sometimes called ‘cat-clays,’ are commonly found on marine flood-plains and if dried, and thus oxidized, characteristics yellow streaks of basic iron (III) sulphate appear.  The pH value of such soils has been known to drop from 6.7 to below 2.0 during oxidation (Tomlinson, 1957) and apart from toxicity arising from acidity per se, toxic amounts of aluminum and iron can be liberated.”

(And further)

“A considerable amount of investigation has been made into the properties of acid sulphate soils, notably in the Netherlands (Harmsen et al., 1954), West Africa (Tomlinson, 1957:  Hart, 1959, 1962, 1963; Hesse, 1961a) and the Far East (Moorman, 1961).  The immediate cause of acidity is bacterial oxidation of elemental sulphur and is limited by the rate of formation of elemental sulphur from the soil polysulphides.”

(And lastly)

“And apart from any polysulphides deposited, the soils (submerged) accumulate.” 

The Sulfur Cycle also helps explain the yellowing or browning of salt marsh plants described as recent salt marsh dieback.  The yellowing of plants is a typically a sign of sulfur toxicity.  Lamers et. al., in Frontiers in Plant Science 2013 4:268 describes sulfide as a soil phytotoxin and looks into this very critical sulfur/sulfide impact,

“In wetland soils and underwater sediments of marine, brackish and freshwater systems, the strong phytotoxin sulfide may accumulate as a result of microbial reduction of sulfate during anaerobiosis, its level depending on prevailing edaphic (soil properties) conditions” and from Lamers (2014) this information is even more important, “as anthropogenic inputs of sulfur into freshwater ecosystems and organic loads into freshwater and marine systems are still much higher than natural levels, and are steeply increasing in Asia.  In addition, higher temperatures as a result of global climate change may lead to higher sulfide production rates in shallow waters” and finally from Lamers (2014), “in marine and brackish ecosystems, sulfate concentrations are 10 to 1000 times higher compared to freshwater systems (Marschner, 1995), stimulating sulfate reducers that play an imminent role in decomposition (Jorgensen, 1982) and concomitant sulfide production.  Hence, the role of sulfide as a potential natural toxin in saline sediments has been well established” (Carlson and Forrest, 1982; Ingold and Havill, in 1984.) 

The return of the sulfur – sulfate reduction cycle has tremendous habitat impacts for our inshore fisheries.  It was Mr. Hammond who reinforced my concern on a growing marine compost fishers called “black mayonnaise” but he termed Humus.

The Salt Marsh Dieback and The Sulfur Cycle -
Many current reports that discuss salt marsh dieback link it to poor water quality and almost never mention that salt marshes are bathed in tremendous amounts of sulfate, the high heat bacterial or the reduction in salt marshes that forms peat.  In fact when articles describe salt marsh dieback, mostly manmade changes are proposed to be the reason, such as poor water quality, dredging or the introduction of non native species and finally nitrogen pollution?  Almost no mention the sulfur cycle and very few mention warmer temperatures (which is actually quite a surprise with all the global warming media coverage) or the bacterial source of salt marsh peat decay and byproduct impacts upon habitat quality (hydrogen sulfide) to fish and shellfish species.  (See Environment Conservation Post #7, The Blue Crab Forum September 2015).

Most reports link increases in hydrogen sulfide to excess nitrogen when reference reports (historic) and recent research indicates that nitrate has a significant role in sulfate buffering.  Almost no information is provided for the sulfur source in hydrogen sulfide.  (Nitrate Reduction in a Sulfate Reducing Bacterium De Sulfovibrio Desulfurricans, Isolated from Rice Paddy Soil, Sulfate Inhibition, Kinetics and Regulation Max – Planck Institute Marbury Germany Feb 2014).  Quite simply high heat organic digestion by sulfur reducing bacteria makes the marsh surface “soft” holds more water as peat root tissue now dissolves and more water (sulfate) means more sulfate reduction.  In long periods of heat marshes sink faster than they can collect surface organics.  Some studies point to a lessening of organic inputs for deepening Sapropel deposits when mostly an increase of terrestrial leaves occurred post 1972?.  Very few researchers mention this sulfur “bacterial battle” happening on the surface of salt marshes themselves but describe in detail “cultural eutrophication” assigning much of the blame upon coastal residents?  (The Blue Crab Forum™ Environmental Conservation Salt Marshes #9 December 2015 and EIC# 10 December 17, 2015). These reports should include a lengthy review of the sulfur cycle for the public (my view).  (For the record – coastal residents did not create sulfate reduction, it is a natural process that is accelerated in heat.  Mention of similar salt marsh conditions were described by Nichols 1920 (Torrey Botanical Society) following the last hot period in New England 1880-1920) almost a century ago).

In a way salt marshes in order to survive now fight a two front war – rising sea level that brings in greater and greater amounts of sulfate, and heat which increases sulfate reduction and sulfide production from far below – in other words the peat below the marsh surface is now being digested (eaten) by sulfate reducing bacteria and as evidence of this process are increased sulfides from it.  The surface of the marsh is responding to oxygen and the rapid cycling of organic matter while deep below – heat now speeds up the very slow process of sulfur reduction.  The marsh can be subject to bacterial action at the surface and now below.  In winter with colder temperatures much faster oxygen reducers (bacteria) now reduce surface organic matter – slowly salt marsh levels stabilize but then may subside as heat continues.  Bare “burn through” areas may now develop as “pools” as these areas become super hot and burn from the surface below.  Sulfate digestion from below has been shown to puddle Sapropel as more and more root tissue peat is consumed.  Sealed from oxygen these peat deposits “cook” and the marsh surface may suddenly collapse.  (These collapses can occur on land also).

George E. Nichols who wrote a bulletin for the Torrey Botanical Club in 1920 (The Vegetation of Connecticut) a botanist, he provides many clues to sulfate peat digestion (rotting) at the end of this very hot period 1880-1920.  On pages 531-532 (Nichols The Vegetation of Connecticut) is found this section.

“There is one peculiar feature of the upper littoral marsh which has already been suggested, and that is the occurrence, scattered here and there in greater or less abundance over the surface, of shallow depressions (FIGS 7, 10), usually muddy or occupied by tidal pools at low tide, and strikingly different in the character of their vegetation from the adjoining higher and better drained parts of the meadow.  These salt meadow pools and “rotten spots” (technically termed “pans” T.Visel), the origin of which will be described later, may lack vegetation entirely, so far as the higher plants and concerned; and, while the alkali grass is frequently present, the salt meadow grass and the black grass are almost invariably absent.  The character plants are usually two, namely the salt marsh grass and the samphire. Singly or in association, and not infrequently accompanied by the sea lavender (Limonium), these may predominate over considerable areas of undrained or poorly drained ground; but, even for them, the soil conditions are not wholly favorable* and very often they succumb to their manifestly unsuitable environment.  The salt marsh grass, in such situations, commonly assumes a low, impoverished habitat, often failing to flower, while samphire and sea lavender grow much less vigorously than on better drained soils, frequently exhibiting a very sickly appearance (FIG. Cool.”

And on page 545 – the origin of salt marsh depressions or pans – mentions plant vegetation covered by loose vegetation smothering the existing plant cover, (Johnson and York 1915) “subsequently (Johnson and York15) he maintains, rapid decay sets it, affecting not only the aerial plant organs, but the underground parts as well, and eventually a depression of some depth may thus arise.”

The above generally describes the build up of sulfides by sulfate reduction of plant tissue, sickly “appearance” is thought to be from sulfide toxicity.  The sinking of salt marshes or excess ammonia from sulfate reduction can be found in New England and the Long Island Sound Region.  A New York Department of Environmental Conservation June 12, 2014 correspondence to FEMA refers to this concern indirectly – on page (4) to Laura A. Phillips Executive Director Sandy Recovery Office.

“Indeed, prior to understanding the mechanism by which excess nitrogen degrades and destroys marshlands, resilient marsh lands were documented as reverting to un-vegatated and submerged mud flats within the nitrogen impaired Jamaica Bay.”

Many New England homes close to the shore or built over filled salt marshes may have the same “settling” condition.  This is related to slow sulfate reduction below the surface.  The largest source of organic matter to salt marshes is from land (leaves) although much research has linked excess nitrogen to plankton growth – plankton is quickly digested in an active bacterial spectrum.  Oak leaf litter is not – its cellulose is more complex its “tough” and takes much longer to digest.  The small amounts of plankton deposited in a marsh surface are exposed to oxygen twice a day – it does not last long in this environment.  Peat deposits sealed from oxygen are reduced slowly.  That is how the peat in a salt marsh is formed over time –and do act to store carbon as part of the organic matter reduction process.   Some reports to this condition have already been recorded for salt marshes.

In a 1994 Guilford, Connecticut study the difference between sulfur digestion and that by oxygen is reviewed in detail (Wetlands Restoration Investigation Leetes Island Salt Marsh Guilford, CT – March 1994 US Army Corps of Engineers – New England Division – A Section 22 report) for a Connecticut salt marsh.

The foreword to this section 22 report (prepared by the Connecticut Department of Environmental Protection, Office of Long Island Sound Programs) for the Leetes Island report i pages to vii 1994) has this section, brackets indicate my insertions.

“The Soil in a salt marsh is known as peat, which is composed largely of the decomposing remains of plant material.  Organic peats only form when the soil is water logged and anaerobic (no or low oxygen – T. Visel) under these conditions, iron combines with sulfate (a common constituent in sea water T. Visel) to form the mineral known as pyrite.  Draining of the marsh causes the water table which is normally within several inches of the surface to drop several feet.  Thus the upper several feet of the soil (salt marsh peat T. Visel) are now exposed to oxygen or oxidized.  Under these conditions, the organic component of the soil decomposes at a very rapid rate.  The most immediate consequence of the decomposition is a long term lowering of the marsh surface elevation, an effect called subsidence.”

However, sulfate digestion has terrible habitat repercussions for salt marsh life as this 1994 Guilford study continues on page i, “Draining (or in times of high heat and drought – T. Visel) causes chemical changes in the soil which cause the marsh to become a non point source of water pollution.” 

The ammonia surges from sulfate reducing bacteria now favor those algal species who are adapted to using it namely, the “Browns” and in shallow water the thin bladed habitat aggressive sea lettuce Ulva – lactuca.  Other negative chemical and technical pollution sources are further described in the report.  And these are the near shore and coastal environments for the blue crab – colder – (but not very cold) keeps the sulfur cycle at bay – crabs can live in New England but we depend mostly on megalops swept up in the gulf stream with prevailing winds blowing, larval stages towards coastal areas.  With warming blue crabs do better in New England and may close the reproduction cycle in July 2011 have evidence of three distinct waves of blue crab megalops and larger numbers of female sponge crabs.  Heat to extremely hot returns the sulfur cycle deadly in shallow marsh habitats (sulfide kills) but gradual warming seems to be the best times for New England blue crab. The report also details the consequences of the sulfur cycle regarding the habitat services of the salt marsh becoming negative including the formation of sulfuric acid, and on page ii is found this section. 

“Draining causes chemical changes in the soil which cause the marsh to become a non point source of water pollution.  Specifically, pyrite is unstable when exposed to oxygen.  Through a series of chemical reactions, pyrite is converted to sulfuric acid which in turns causes a drastic decrease in soil and creek water pH.  Levels as low as 3 to 4 (pH T. Visel) are not uncommon in drained salt marshes.  These altered soils are called acid sulfate soils.  Under such low pH valves the aluminum associated with natural days is mobilized and this metal is toxic to aquatic organisms at very low concentrations.  Where dissolved oxygen levels have been monitored in drained salt marshes, low dissolved oxygen levels, known as hypoxic, have been observed during summer months following rain storms.  It appears that the leachate removes oxygen from the water fish kills have been observed in some of these wetlands.”

Sulfate reduction can also occur in high heat, sulfides can accumulate and eventually kill salt marsh plants themselves.  Most of us have seen the impacts of sulfate acidic soils killing trees in a wetland. In Connecticut roadway construction has at times blocked the natural north/south drainage pattern causing some low lands to become wet with trees that in time perished.  These trees eventually turn into silver colored sulfide stumps.  No leaves and falling branches are seen as they are slowly dissolved.  Submerged soils once re-exposed to oxygen can become acidic as in a drained salt marsh.

Many ecologists correctly anticipated the oxygen nitrogen cycle and the formation of sulfuric acids from oxygen reducing bacteria but were surprised by high heat sulfate reduction.  In very hot summers low oxygen now favored sulfate reduction and lethal concentrations of ammonia, basic pH levels and at times hydrogen sulfide discharged from salt marshes.  That is why on hot August nights that some salt marshes “would smell” of sulfur in the 1890s that or “rotten eggs” and in 1990s again as “match stick” or “low tide” smells.  In winters sulfides can move to the surface in coastal habitats and kill hibernating blue crabs, terrapins and even conch (see Blue Crab Winter Kill – June 15, 2015).  Ice covered salt ponds on Cape Cod still may sustain such sulfide winter kills for fish – warnings are still issued about them on the Cape.  (See Massachusetts Division of Fisheries and Wildlife Office of Fish Kill Coordinator).

Sulfate reduction of peat would be far more deadly creating sulfides and ammonia discharges toxic to most sea life.  As ample sulfate bathed hot salt marsh surfaces they “burned” into the sulfur cycle.  The smoke of this reduction was ammonia and in hot periods sulfides.  The largest toxic difference was sulfate reducing bacteria that needed heat and organic matter also caused disease – the Vibrio series.  High heat and the sulfur cycle would in times become negative habitat services killing sea life that in the cold or oxygen reduction provided benefits.  While the sulfur cycle is slower and salt marshes can build in warm – hot cycles at times can make them natures killing fields.  (Environment and Conservation #7 dated September 10, 2015, The Blue Crab Forum™).   

Salt marsh articles that describe dieback surface changes or subsidence should mention at the very least sulfur reducing bacteria and the sulfur cycle – my view T. Visel).  (See Nitrate-Based Niche Differentiation by distinct Sulfate Reducing Bacteria Involved In The Anaerobic Oxidation Of Methane, A. Green Saxena et al. – ISME Journal 2014, Vol 8 pgs 150-165 California Institute of Technology).

The Sulfur Reducing Bacteria

It is Mr. Hammond’s suggestions about the sulfur cycle that is coming home now as in the growing Vibrio bacteria association to eelgrass meadows is pouring in from overseas.  As we experienced hot weather in 1998-2012 so did other countries.  Vibrio bacterial pools are being found under eelgrass and other vegetation in growing numbers, overseas and here in the United States.  (Ecology of Vibrio parahaemolyticus and vibrio vulnificus in the Coastal and Estuarine Waters of Louisiana, Maryland, Mississippi and Washington (United States) Johnson et al 3 – August 2012 Applied Environmental Microbiology Vol 78 20 pages 7248-7257).  (Sediment and Vegetation as Reservoirs of Vibrio vulnificus in the Tampa Bay Estuary and Gulf of Mexico, Eva Chase et al Applied and Environmental Microbiology April 2015, Vol 81 #7).  (Changes in Community Structure of Sediment Bacteria Along the Florida Coastal Everglades Marsh- Mangrove – Seagrass Salinity gradient – National Science Foundation – The Florida Coastal Everglades Long Term Ecological Research Program Ikenaga et al Florida International University Microbial Ecology 59 (2) pages 284-295).  (Cultivation Dependent Analysis The Microbial Diversity Associated With The Seagrass Meadows In Xincun Bay South China Bay, Ling et al July 2015 Ex toxicology).  (Seagrass Vegetation and Meio Fauna Enhance The Bacterial Abundance in the Baltic Sea Sediments (Puck Bay) Jan Knowska et al Institute of Oceanology Polish Academy of Sciences, Warsaw Poland Environmental Science Polluting Research 2015 22 (18) pages 14372-14378 – online July 2015).     

Mr. Hammond’s sulfur cycle chapter had included them back in 1982 on page 303 in a clear diagram showing bacterial reduction represented by “Desulpho Vibrios.”  To be honest in 1982 I didn’t know what Vibrios were exactly and I didn’t really understand how important the sulfur cycle was to coastal ecology or fisheries for that matter.  I do now.  Many fishers have not yet heard the term Sapropel, or sulfate reducers or sulfide toxicology, all parts of the sulfur cycle.  Instead the sulfur cycle largely a natural process has been pushed aside for the oxygen/nitrogen cycle, which is dominant in cold, when sea water temperatures allow “better” oxygen saturation. 

In heat the sulfur cycle dominates with its terrible consequences and certain death for many organisms we call seafood.  We see the impacts of heat in disease outbreaks as well and now it appears Vibrios is a large factor.  That discussion until just a few years ago was “missing” from our coastal studies until people started to get sick.  The diagram on page 303 references the work of Butlin in 1953.  The Vibrio connection to sediments has been in the research community for over a half century.  The return of heat will strengthen the sulfur cycle and within strains of disease causing bacteria – that is rarely mentioned in current salt marsh papers.  These bacteria like heat and researchers continue to find examples of them.  A January 2015 USC University of Southern California press release titled “New Species Discovered Beneath Ocean Crust” describe hot thermal ocean floor vents as containing microbes (bacteria) that “breath sulfate.”

The Basic Question Is Why – The Neglect Of The Sulfur Cycle?

The sulfur cycle is directly connected to the rise of aquatic vegetation, especially eelgrass.  It is under eelgrass that collects organic matter and fosters the growth of the first Vibrios.  Almost every week a new reach paper from overseas mentions this aquatic vegetation – Vibrio link but here that part of the sulfur cycle is missing from east coast eelgrass research – it’s just not mentioned.  The dominant habitat type in shallow low energy areas (in heat) is Sapropel the organic compost that is produced by sulfate reducing bacteria.  The very first Sapropel deposits can be found under eelgrass matts which naturally collects organics.  In many respects eelgrass helps the sulfur cycle begin in coastal habitats by feeding its sulfur reducing bacteria.  That aspect of toxic sulfides and sulfuric acid formation is also missing from many eelgrass studies.  In fact some Vibrio bacteria can only be found under eelgrass meadows.  (Different Bacterial Communities Associated with the Roots and Bull Sediment of the Seagrass Zostera marina Sheila Ingemann Jensen, Michael Kuhl and Anders Prieme, October 2007 Microbiology Ecology Pg 108-117).

Several questions came in about eelgrass and blue crabs, and habitat quality after the E/C #10 posting.  Eelgrass is part of a complex habitat history – thin Sapropel and eelgrass in cold water has sufficient oxygen and provides good blue crab habitat services.  This is the “clean and green” eelgrass, sandy soils, cool oxygen rich waters and good tidal flows.  That is the eelgrass pictured in many eelgrass reports, but eelgrass as with many habitat types and in the tidal estuary has a life, that is it succeeds over time absent of energy, they “age” and change.  The mispresentation of eelgrass and eelgrass meadows is that they are not constant – they often succeed over time and in time (heat) the “brown and furry” eelgrass emerges.  That habitat history just did not get into the recent eelgrass “movie.”  Those pictures (footage) I guess ended upon the cutting room floor.  The public rarely has seen the end of eelgrass habitat succession – its habitat history is not a great picture after a long period of heat and few storms it grows thick – and as it does it traps organics, some algae but for inshore areas mostly leaves.  In extreme heat it welcomes the sulfur cycle back with all its deadly consequences.

When I was employed by the University of Massachusetts Cooperative Extension Service (in the 1980s) I watched eelgrass in Buttermilk Bay on Cape Cod turn black, and rot.  It was not the healthy eelgrass of sandy cooler soils – this was dying and covered thick ooze which smelled of sulfide – more properly termed Sapropel when disturbed (personal observations).  It was very hot and dry.  It was during this period that eelgrass grew over “black mayonnaise” in Buttermilk Bay and these areas held “little life.”  Something good habitat wise had turned to something very bad.

That is natural, that is what eelgrass does much like terrestrial grasses – it binds loose marine soils and traps organic matter in them.  Some of the first shellfish research reports mention this ability for eelgrass meadows to rise over time and choke tidal flows.  That is why shellfishers noticed a bottom change, it became softer, fungus thrived in them and in time sulfide in heat caused necrotic root failure (eelgrass) and it just “wasted” away.  In the 1930s eelgrass was a victim of the wasting disease a fungus quickly killed weakened eelgrass already in marginal sulfide rich habitats more properly termed Sapropel.  (I have asked Connecticut researchers on February 16th 2016 to adopt this European designation of Sapropel).  As cooler temperatures also bring stronger storms weakened eelgrass meadows were now torn up – Sapropel deposits under them were then washed away such as in the 1930s, 1940s and 1950s.  That is also natural – eelgrass follows hurricanes as grasses on land follow forest fires.  The law of habitat succession also applies in the coastal region as well.  At the end of its habitat “clock” eelgrass turns deadly, it protects Sapropel which now produces sulfides, ammonia and sulfuric acid.  That is also a part of the eelgrass life cycle of habitat – succession which does not get presented in many eelgrass studies and is a form of research omission (my view).  For many fishers this side of eelgrass was never “viewed.”  The historical fisheries literature (my view) was better at presenting a balanced view.  Many times when describing eelgrass mentioning both its positive and then negative habitat services of eelgrass growths in the same publication.  The State of Massachusetts Coastal Zone Management office has provided many historical manuscripts in which this occurs – a more balanced habitat representation.  (I commend them for their cooperation in providing such historical fish/habitat reports – T. Visel).

In times of increasing heat, eelgrass, oysters and blue crabs all do better – up to a point, extreme heat returns the sulfur cycle to these shallow waters, the purple waters, the harmful algal blooms (HABs) and black water sulfide kills, blue crabs flee this sulfide it is a very toxic substance, and oysters will not feed – they starve and in time die.  Sulfides/sulfuric acids build up so high in Sapropel itself they attack eelgrass roots weakening it now for them advantageous fungal attack – mentioned above.  In time these deposits become as Nichols noted in 1920 – a place of limited shore life.   

The end of the Great Heat 1880-1920 a roughly four decade long period of increasing heat and few strong storms in New England Sapropel/eelgrass deposits were deep and thick.  By the 1920s winters now suddenly turned severe colder and storm filled.  Species that had died off in this “hot term” suddenly returned.  The most surprised were Rhode Island fishery managers as the most severe winters now held enormous bay scallop crops not seen for decades.  As colder water extended well into spring sulfide purged from these remaining Sapropel deposits, now thought to kill overwintering adult blue crabs.  The cold water sulfides were as just as deadly in winter as they were in summer.  As the decades past the abundant Blue Crab populations of Narragansett Bay faded with the eelgrass.

The rise of Sapropel and the increase of blue crabs, oysters and eelgrass were all connected, now with a climate pattern shifting habitats were changing as well.  With colder water containing more oxygen Sapropel now purged sulfides and when re-exposed to oxygen sulfuric acid.  Long cold winters now weakened the eelgrass roots themselves and then the plant.  A weakened eelgrass soon fell to warm fungus infections worldwide, starting in 1928 in France – reaching New England between 1931-1934.  With its roots being acted by acids the fungal infections finished off what was left, eelgrass just “wasted” away.  Were blue crab megalops losing a valuable habitat type then yes, but it was the cold that claimed the most – the end of the great oyster sets, the end of the New England “blue crab question” and now the end of shallow Sapropel eelgrass deposits.  By 1938 blue crab populations in New England were in steep decline, by the 1950s it was free fall. 

Habitat Change and Habitat Quality

By the 1938 Hurricane, Sapropel deposits were exposed to full energy from this storm filled period and soon they were gone.  In their place were thousands of acres of cobblestones as sand stripped beaches which soon grew kelp, the age of the blue crab oyster and striped bass were ending – the age of the quahog, bay scallop and lobster was just beginning, that was natural – it is a cycle.  (A striped bass in the colder 1870s over 8 pounds was very rare in Connecticut, they grow very large in periods of heat).

The 1950s and 1960s would be remembered for much colder temperatures and dozens of strong storms and hurricanes in Southern New England especially in Long Island Sound – quahog sets increased in now these cleaned washed marine soils, the kelp cobblestone habitats now helped lobsters recover from the high heat devastating 1898-1905 lobster die off.  Coastal residents from Connecticut to Cape Cod wondered what happened to the huge blue crab populations a half century before as bay scallop production would soar in the same bay bottoms-now mostly free of eelgrass.  The oyster industry great set of 1898 was now just a memory – the remaining oyster companies had already retreated to a few harbors where shallow and easy to warm waters meant good oyster sets there were still possible.  The Narragansett Bay Great Quahog sets in the 1940s and 1950s meant the fishery soared in the 1960s as these seed clams matured into a growing fishery.  Fishers often switched species – bound by commercial expectations – fishery statistics provide important clues when compared to temperature and energy.  As Rhode Island oyster production fell, the hard shell clam quahog fishery soared.  But just what defined these habitats, the changes of temperature, the amount of energy and I contend was the type of bacteria living in the soil itself – determined by the sulfur cycle.

In the heat (and lower oxygen) the sulfur reducing bacteria became prevalent.  They slowly digest organic matter and they are not as efficient as the colder water oxygen reducing bacteria.  Sapropel (a marine compost) builds up in hot periods (salt marshes also) – as this long nitrogen/carbon cycle burns into a sulfur cycle habitat profile.  That reversed in the 1950s colder water meant more oxygen giving the oxygen reducers the edge – much quicker and organic matter was consumed quicker – it did not build up it was quickly “recycled” into a cold water oxygen rich marine food web.  The shift back to the long sulfur carbon cycle would be first reported by shellfishers and winter flounder fishers post 1972 – when it started to warm again.  In the heat and low energy conditions the sulfur reducing bacteria would stage a come back and resemble habitat conditions and species shifts observed between 1880-1920, exactly.  Fishers soon reported that previously hard or firm bay bottoms now became soft and muck filled, they were foul and bad smelling – Winter flounder fishers had specially noticed the change in Jordan Cove in Waterford.  They soon brought this habitat concern to town officials.  It is in eastern Connecticut that the build up of Sapropel was first noticed by fishers – mostly those who fished for winter flounder in the early 1980s.  Within a few years winter flounder were caught with infections and necrotic fin rot.

Waterford Urges Action on Coves

A December 8, 1983 New London Day newspaper article titled “Waterford Studies Urge Action On Coves” focused upon several aspects of habitat change.  While I was on Cape Cod – John A. Scillieri Jr. then Chairman of the Waterford Flood and Erosion Control Board told me about dozens of complaints he had obtained about Waterford’s coves – the changes in bottom and increases of a black like jelly material now suspected to be Sapropel (personal communication T. Visel) and sulfur smells from them in the “hot” summer.  Chairman Scillieri supported dredging and eliminated sewage “tha
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« Reply #1 on: April 28, 2016, 08:12:33 PM »

another great read


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