CTFishTalk.com: The Cycle of Sapropel 1880-1980 IMEP Newsletter #23 -T.Visel - Connecticut Saltwater Reports ( CT Saltwater Reports ) - A Community Built for Connecticut Fisherman.

BlueChip

The Sound School Inter-District Marine Education Program
IMEP Newsletter #23
The Cycle of Sapropel 1880 to 1980

Habitat Information for Fishers and Fishery Area Managers
Understanding Science Through History
(IMEP Habitat History Newsletters can be found indexed by date on The Blue Crab.Info™ website: Fishing, eeling and oystering thread)
Tim Visel, The Sound School

High Heat and Organic Loadings Complicate Nitrogen Limits
Nitrogen TMDL Input Models Need to Include Sapropel
Why We Need to Look at The Saprobien System
Discussion Paper EPA DEEP Long Island Sound Study Habitat
Restoration Work Group
Submitted by Timothy C. Visel1
The proposal to review the role of Sapropel deposits to Nitrogen Total Maximum Daily loads nor low oxygen release of nitrogen compounds from them does not reflect the EPA/DEEP Habitat Restoration Workgroup nor has consensus been reached regarding the existence of Sapropel in near shore coastal habitats of Long Island Sound.

The Sound School – 60 South Water Street
New Haven, CT
September 2013
For Review and Discussion
Revised for Capstone Project Investigations, March 2014
Blue Crab Appendix Attached August 2014

Abstract

The Saprobien System (1909) offers an interesting look at long term habitat reversals. In the historical reports about early studies that lead up to the development of Saprobien System were the reports of fishers, fish wardens, and river keepers in Europe. They reported upon the impacts of high temperatures and organic matter loadings to European river fisheries, habitats and the association of temperature to them is now over a century old. Although here in Southern New England we had The Great Heat beginning in 1880, Europe and especially Great Britain had “The Great Stink” beginning in 1858. Here the Thames River with vast amounts of organic matter putrefied in high heat sending nauseating “bad airs” onto London Streets that were so intense, sheets soaked in vinegar were hung over Parliament windows in an attempt to quell the stench. (Cairns and Pratt, A History of Biological Monitoring Using Benthic Macro Invertebrates, 1999). The Saprobien system classified habitats by the amount of organic matter that overwhelmed a streams natural ability to clear it and listed temperature as limiting oxygen (see Kolkwitz and Masson 1909).

Although the Saprobien system would be modified many times, its first premise included time, as “self purification” of organic wastes, animal and human sewage, and in time slowing moving rivers could “recover” from organic pollution to pre event status. Unfortunately in high heat, the fish (certain species) had long since “vanished” and one of its primary initial indicators was fish species “zones” and the ability to survive in stressful conditions. The presence of intense odors of dead fish often compelled “such studies.”

The events that drive our habitat intervention unfortunately are historically both most severe and public. Hugh Hammond Bennett, in his attempts to gather a national consensus here about soil loss and habitat conditions of the growing dust bowl in the 1930s was unsuccessful in Congress until a huge dust storm actually hit Washington, DC. Alerted of its Capitol approach by colleagues in field stations, he timed a congressional debate hearing for 2 pm and arranged for drapes to be removed from the windows and tables pushed to them. At 10 a.m. in the morning D.C. street lamps came on, residents were frightened by darkening of the sun, people swarmed hospitals with respiratory distress coughing and eyes watering from the dust as Congress started the debate over a national soil conservation program at 2 pm. Bennett is told to have addressed the group and said something to the effect, “Gentlemen, this is the situation that I have strived to communicate to you, as you can now see, it is here.” Legislation for the Soil Conservation Service was approved shortly later. The truth of the matter was by the time the Soil Conservation Service was created the drought that had occurred for decades was beginning to moderate. With good soil conservation and management practices (and the rain of course) badly eroded fields began to heal and then hold soil and plants again. Climate conditions were changing and we did not have at the time a sense of environmental history.

Introduction

In the marine field we also react slowly to such large habitat changes. After returning to the University of Connecticut in 1983, I had worked briefly with Richard Loring of then Culture Clam in Barnstable, a hatchery producing hard clam seed on the Cape.

Hard clam (Mercenaria mercenaria) inshore sets had largely failed on Cape Cod and the hatchery produced “seed clams” for a growing Quahog aquaculture industry. Soon my work with area fishers I learned that widespread hard clam sets had mostly stopped on the Cape and the need of hatchery produced seed soon increased. My interest in the box culture of clams and the soil growth characteristics in them grew; when I returned to Connecticut many formerly productive inshore coves and bays for hard clams that had also become nonproductive. Upon the request of the Waterford –East Lyme Shellfish Commission, (Robert Porter, chairman), a similar culture experiment was conducted in Smith Cove, a westerly lobe of Niantic Bay. Several thousand Mercenaria seed were purchased and planted in a wood rectangular box placed with j hook re-rod metal stakes, similar then to the Wellfleet method; we wanted to be able to then return to the same location to monitor growth. Several months later we returned to check on the growth of clams but instead found a black soupy leaf mixture that had covered the culture box. The characteristic sulfur smell soon became noticeable as we examined the clams, most had died, and the shells were soft and chalky. Below surface leaf deposits a black jelly and greasy material had formed – termed Sapropel.

The blanket of oak leaves no doubt had suffocated the clams and now the acidic conditions from the oak leaves themselves had eroded shells. In many instances the clams had become smaller. It was disappointing for Mr. Porter to see this type of acidic bottom, it certainly wasn’t like the one he had experienced growing up on Niantic Bay. Smith Cove had a sandy and shelly estuarine bottom then. It was now a soft organic filled mucky organic bottom, the habitat clock for that habitat succession period had long expired. We did scrape this Sapropel off and found black stained sands below with an occasional empty clam shell. It was obvious that this area once supported clams sets, but habitats now contained Sapropel. He tried to save as many clams as he could but was interrupted by a neighbor dragging a tarp full of leaves to dump in the cove, and the discussion then became somewhat “heated.” I left and later Bob told me that after the leaf burning ban, neighbors just started dumping leaves into the cove, believing the tides would “take them out to sea.” We had no idea at the time how leaves would impact the clams, but taking what I had learned on the Cape, we changed the soil for some gravel and bagged sand, and as John Hammond and George McNeil suggested, mixed in some crushed clam shell (obtained in buckets from Harborside Seafood in RI). It came as an aggregate (mostly driveway material) and we mixed that in to this “new bottom,” Clam growth of the remaining clams was nothing short of spectacular; I wrote this restoration project up in 2005 and presented it in 2006 at the International Conference for Shellfish Restoration in Charlestown, South Carolina. Source: Connecticut Shellfish Restoration Projects Linked to Estuarine health by Timothy c. Visel, Coordinator, The Sound School Regional Vocational Aquaculture Center, 60 So. Water Street, new Haven, CT 06519. (tim.visel@new-haven.k12.ct.us).
[A series of CT Sea Grant/Extension shellfish restoration programs for hard clam (Mercenaria mercenaria), soft clam (Mya arenaria), oyster (Crassostrea virginica), and bay scallop (Arogopectin irradians) were coordinated with local municipal shellfish commissions in the 1980s. Potential candidates for projects were identified by local environmental fisheries history, shellfish maps, natural beds and local shellfish surveys. Several restoration projects were undertaken with federal, state and local agency assistance. Results were highly site-specific; some yielded almost immediate positive results and some were complete failures
Predictions/suggestions by the local residents and resource user groups were often confirmed; therefore, their importance and contribution should not be overlooked. Environmental fishery history reviews can be an important tool in understanding the declines in shellfish production from near shore areas. As much information as possible should be obtained before attempting shellfish restoration programs. In this way, scarce shellfish restoration resources can be maximized.
”Connecticut Shellfish Restoration Projects Linked to Estuarine Health” 11:30 Plenary Concurrent Session E “Small Scale Approaches to Shellfish Restoration” – 9th International Conference on Shellfish Restoration; November 15-19, 2006, Charleston, South Carolina, USA]

Although the hard clams grew well in the culture box, when planted into the adjacent open areas, they did not grow and eventually died off. Although Bob blamed the neighbors for the leaves, trees had grown up along the entire Niantic Bay and the marine soil itself had changed; it was acidic and under the remaining eelgrass patches we did find buried dead hard shell clams. The clock of habitat succession had simply run out for hard clams. In this section of Niantic Bay, the ice filled cooler and stormier 1960s had gone and with them hard clam habitats, but continued shellfish survey work showed Niantic Bay now had a huge set of sub tidal soft shell clams, (steamers) in areas of no leaves. Bob was surprised to see them, as when he was young, steamers (Mya) were rare and largely nonexistent in Niantic Bay, to him, it was perplexing to see a reversal of species and habitat types over several decades. In the marine environment our dust storms are our forest fires and hurricanes and the winter equivalent Nor’easters, our floods. It’s not that acidic bottom conditions were unknown, David Belding at the turn of the century properly identified the negative impacts of organic acids upon shellfish in marine soils (1910-12) but only recently has acidic soils been reviewed in regards to shellfish sets (Dr. Mark Green, St Joseph College Maine). The source of the acid conditions, I feel can be attributed to leaves and organic matter that in oxygen limited conditions formed Sapropel. And, it is not just one event usually, but habitat reversals sometimes take decades.

One of the chief aspects of the Saprobien System is time for “self” purification for habitats to “restore” themselves to a certain expected level of habitat quality. In marine studies this puts researchers at a great disadvantage; we need much longer periods of study (time) to review changes. In 1990, few saw the lobster die off of 1998 and a decade later, a surge of blue crabs. I didn’t either, but I would very much recall the habitat reversal pattern. Just as Bob Porter returned to his hard clam grounds of the 1960s, that habitat had “succeeded” as new trees grew up and matured, although neighbors dumping leaves certainly had helped speed the succession process. The previous sandy/shelly habitat now contained what fishers call “Black Mayonnaise.”

The entire state of Connecticut was recovering its forest canopy, once largely cleared for agriculture; the stormy period of the cooler 1950s and 1960s was over. Leaves now collected over marine soils once cleared by waves and the areas that obtained the least energy. In 1935, agricultural fields occupied 67% of Connecticut’s land acreage; by 1985, only 13% (Lewis, 1980). Many rivers blocked by tidal restrictions (undersized culverts and poorly designed railroad crossings) dams or had long connections to the sea, slowly started to fill with organic matter, primarily leaves. This can also happen during long periods of heat, or when sand waves or sand bars can be driven into the mouths of rivers and coves creating a “sill” or bar partially blocking tidal exchange. Alewife Cove between Waterford and New London is an excellent example of sand bars restricting tidal exchange and buildup of black mayonnaise behind them. The formation of a barrier sill reduces flushing so trapped nutrients and organic matter collects even faster, as organic matter builds that reduces hydraulic capacity as less oxygen containing sea water is exchanged during tides and coves “fouled.” In hot weather these organic accumulations can act as nitrogen sink or storage capacity. As Sapropel builds it allows sulfate reducing bacteria to shed ammonia compounds fueling additional vegetation. Most Connecticut lake associations have experienced sulfur rich (toxic) Sapropel deposits and have them periodically removed or cleared by dredging. In this case the dam also acts to accumulate organic debris which rots in low oxygen conditions.

Some of these coastal storm blocking energy case histories can be found in colonial New England with examples opening of salt ponds. Salt ponds cut off from cooling ocean exchange in high heat putrefied, and fish kills called black water kills were common. These habitat changes were so quick, they were very noticeable (did not take decades to occur) and local interests acted and unblocked or “breached” them. The opening inlets that were important to local herring runs, as herring rights (alewife) were subject to public bidding and franchises. A short case history of Quiambaug Cove in Stonington Connecticut mentions the use of oxen. The restoring of tidal energy has been a part of New England’s salt pond fisheries history.

What was once a small concern of the river oyster tongers of the 1930s and 1940s; tons of leaves now buried river oyster beds in the 1980s. As temperature warmed into the 1980s and 1990s, those leaves rotted and Sapropel formed first in the quiet coves and head waters of tidal streams. The people who noticed it first, as bad smells foul or “sour” bottoms in the marine fisheries were the quahogers, bay scallopers and winter flounder fishers. They could see habitat change over time and had vested interest in habitat quality of their fisheries. No one I feel was expecting what paved streets, a renewed forest canopy and a regional leaf burning ban would have upon the Alewife fisheries. I was to witness that on Cape Cod and to the long hot period and relatively few storms that was to bring a surge of blue crabs in Connecticut not seen here since the last Great Heat. A huge habitat reversal from the 1950s and 1960s was happening. The age of the lobsters in Connecticut had now ended, and the age of the blue crab just lay ahead.

The Saprobien system offers us a different approach one that looks at temperature (climate) and energy and the ability to remove organic waste in all moving streams. Although researchers Kolkwitz and Masson (1909) used biological indicators to describe the qualification of habitat quality, the basic reasons were biological reduction processes that first consumed oxygen and then sulfur reduction naturally recovered as a self purification cycle is still important today.

The Danger of Sapropel

Sapropel is a natural substance that occurs naturally in high heat. Dead zones or low oxygen conditions were also present in the 1950s and 1960s (it’s just that they were much smaller). It wasn’t that this situation was unknown to marine researchers; it was in fact in a book titled Estuaries (George H. Lauff, 1967 – American Association for the Advancement of Science #83, Washington DC, 1967- W.K. Kellogg Biological Station). It did get a mention on page 378. “To some extent, the reduction in photosynthesis and dispersal of bacteria laden debris particles reduce the oxygen “tension” of the estuary. Because of waves and water movement however, low oxygen conditions are rare in estuaries except where the flow rate is low. This sometimes occurs the near the bottom, especially at low tide and at night (Day 1952).” Thus the often common reports of “low tide” smells of Connecticut salt marshes during August.

But low oxygen zones were not of great significance in the 1950s and 1960s, four factors would greatly change that, the warming period post 1974, the dramatic drop in the number of storms (CT DEEP has an outstanding reference table that anyone studying climate and energy pathways should look at, it is titled the Coastal Hazards Library), the return of forest cover leaves and the paving of road surfaces would all combine in a much different estuarine organic matter input than during the North Atlantic Oscillation of the 1950s and 1960s. It just didn’t register on the radar then as a concern. In fact some Long Island Sound researchers felt the Sound was “nitrogen limited.” As tree canopies rebuilt and roads were constructed, the first brown water reports can be found (mostly from trout fishers) first during the 1880-1920 periods when New England brook trout habitat failed (too hot) and then again in the late 1970s as the heat retuned.

Rains then started to wash huge amounts of leaves (accumulated in heat and few storms) into estuaries, mostly oak and maple leaves, both with a pH less than four such as vinegar. Roads provided a conduit that led directly to water sheds that carried ground up street leaves, stems and sticks that the Cape Cod fishers in the 1950s termed “oatmeal” chaf into streams. This slurry of brown fall leaves carried pigments tannin a “bio pigment” that is brown thus the brown water or chocolate flood waters – often a frequent report after heavy rains.

Some of the first instances of Sapropel toxicity can be traced to the agricultural applications of “marine mud.” Coastal farmers in the lower Connecticut River had harvested what was called north of Connecticut “mussel mud” for fertilizer- the “older” the Sapropel the more sulfuric acid it contained – (CT Agricultural Experiment Station Report, 1879) Connecticut River area farmers soon learned that old Sapropel was not only foul smelling (sulfur compounds of the infamous rotten egg order of the Great Heat), but deadly to all crops. The putrefied organic matter that had proved to be deadly to field crops was worse behind mill dams, as its age tended to increase sulfide levels. From lack of oxygen and little disturbance leaves collected behind dams and putrefied when it became very hot and coastal storms declined. Barrier beach inlets also “healed” and these natural features acted much like natural dams and trapped organic matter behind them. Soon “chocolate waters” became “black waters” and fish kills with pungent sulfur smells increased. When heavy rains occur after a period of low coastal energy and high heat, they can carry vast amounts of resuspended Sapropel downstream – killing fish and shellfish below. Sulfide winter kill events are still recorded in Massachusetts- mostly in coastal salt ponds.

This is something that the July 2011 Blue crab reporters mentioned several times this “brown water” and also this year (2013) in the Connecticut River, it was brown for weeks. Our trees have helped oxygen depletion worse and even the dominant tree species have a role. Oak leaves resist oxygen decomposition processes their cellulose structure quite simply is tough – hard to break down by oxygen reducing bacteria, instead they become food for another different type of bacteria – once that reduce organic matter by way of sulfur in the absence of oxygen. It is the process that releases waxy hydro carbon molecules from cellulose digestion and gives Sapropel its greasy feel. It is even possible to identify vascular plants sources (P. A. Meyers Organic Geochemistry 2003). So how much impact does this leaf matter have in estuaries, I believe it to be tremendous, perhaps equal to or surpassing the negative effects of human nitrogen inputs especially when indexed with temperature and energy and begs the question of the role of energy and temperature in the TMDL nitrogen pollution issue.

In the 1950s and 1960s, Connecticut’s coast sustained a series of powerful storms and it was cold, and cold water contains more oxygen (inverse solubility law, the colder the water the more oxygen it can hold). Leaves just didn’t hang around and pile up. They quite simply were consumed by shrimp or were washed away by the storms estuarine bottoms were firm and often shelly (alkaline conditions) as reported by fishers, waters were cold so the increase of trees (leaves) and roads many “storm water” carrying organic oatmeal into bays and coves largely went unnoticed except by perhaps trout anglers who watched trout streams and alewife runs on Cape Cod destroyed by leaves. Later the shellfishers noticed it covering river oyster beds, followed by the winter flounder fishers who reported fin rot in fish caught in areas now covered by acidic black mayonnaise and acidic marine humus much from oak and maple leaves now properly termed “Sapropel.”

Fishers frequently noticed the toxic sulfide impacts after heavy rains as the organic matter putrefied and turned brown to black. When Sapropel (called Black Mayonnaise along the coast) is disturbed it often emits a sulfur smell. These habitats were reported to be toxic to Brook trout at the turn of the century and created the programs for transplants for more heat tolerant trout species such as Brown and Rainbow trout.

In the 1970s the water warmed, energy stopped, roads were in place at the same time Connecticut’s forest recovered from agricultural cutting of the previous two centuries. Leaf litter and organic matter accumulated in watersheds for decades.

After heavy storm rains, organic matter rushing in storm water discharges clogged trout streams, and later alewife runs. Then came the prohibition on burning leaves – an increasing fall activity for many New England homeowners. I don’t think anyone really anticipated the impact that would have in the coastal region. I can remember my father who was an avid trout fisher complaining bitterly about the destruction of “natural drainage” and its impact upon trout stream habitats in the 1940s. I had no idea how that observation would influence my later natural science research efforts. So I feel it was the trout fishers who were the first impacted by the return of the forests, and storm water from roads which now made fly fishing only viable upon the largest ponds. The days of clear out open streams for agriculture were coming to end, habitat succession was in full swing post War World II, and as the forest returned, more roads were being built. Trout habitat now came under attack by increased leaves, and “storm water” that carried those leaves into the brook trout habitats. Trout habitats were greatly impacted but nothing would rival the impacts of leaves to alewife runs which remain a huge issue even today. Some alewife runs are totally blocked by leaves (and fallen trees and branches) while others filed with a century or more of street sand. While fish ladders are installed the habitat quality of such runs are often ruined by silt and leaves. The leaves of course also rot in high heat and continue degradation downstream with sulfur residues. In this case leaves could have been classified as a pollutant – at least in terms the alewife especially habitat quality alewife runs into old mill ponds which may now contain several feet of Sapropel behind them. It is often described as a “sulfide block” and if strong enough can kill fish outright.

The much colder 1870s saw Connecticut streams ice covered and cold water ice “caps” did help clear streams of organic matter and help Brook trout habitats recover. Ice over streams had already been linked to a Venturi effect of creating tremendous scouring currents. George McNeil an oyster grower that spent his final years growing oysters in Clinton Harbor recounted how heavy rains while ice still covered the lower Hammonasset River cleaned and washed upper oyster beds while the lower beds – notice covered were blanketed with three to four feet of black leaves. If the leaves were not moved they would have suffocated the lower oyster beds – he had noticed a dramatic increase in leaves and suspected that leaves were being dumped into the river as it was taking longer and longer for them to disappear. He saw the return of leaves as a growing problem to oyster culture in coastal rivers and bays in many areas.

Habitat Succession was occurring and oyster growers were some of the first one to record it. This habitat change mirrors that a century ago. Some of the first warnings about “stagnant waters” can be found in the United States Fish Commission reports of the 1880s. Here manure waste from dairy farms rotted and became a nutrient source in estuaries.

Connecticut a century earlier had now become a productive dairy state, lands were cleared beyond that of the first agricultural settlements to industrial scale as a war recovering nation found many southern farms ruined. Here would be another warm period with organic matter – manures. Fishers also noticed the problem with factory wastes as water courses delivered this pollution “to them.” The waters were often tinted from chemical dyes - waste cellulose paper, pulp or chemicals. Rivers and streams merely became natural conduits to carry polluted wastes to the seas. But they also noticed those dairy farms and the industrial practice of using streams to carry manure wastes. A sludge (often black) was linked to dairy farm manure in Groton, Connecticut in the 1880s. Shellfishers on Long Island had complained about Sapropel formation from duck farm operations located in areas of low energy. In one of the more significant habitat case histories involving putrefied organic matter (US Army Corps of Engineers – New York District, Suffolk County New York, Appendix D 2009 is found regarding the Long Island Duck farms. In the 1950s and 1960s discharged duck farm waste occurred into sluggish coves were unsuited to naturally clear such organic matter. Similar problems confronted many of the first cultured Atlantic salmon operations in the North Atlantic. As organic matter accumulated “duck sludge” underwent classic sulfate reduction as sulfur reducing bacteria increased the presence of hydrogen sulfide. Not unlike observations of the Narrow River in Rhode Island or interviews with Niantic Bay, Connecticut residents “sulfide fogs” could discolor paint on homes or acid drips below street lights destroy car finishes. Page 16 of the 2009 study of this sludge problem mentions complaints of paints on homes being discolored – referenced in 1964 and 1972 reports. By the late 1960s the Federal Water Pollution Control Administration had already recommended removal (by dredging). Once Sapropel forms, it can exist for centuries and become increasing acidic from slow sulfuric acid build up. Although most of the Long Island duck farms have now closed, the Sapropel (mentioned as sludge) remains and becomes more toxic to marine life as sulfur bacteria increase. Heavy organic matter accumulations that reduce tidal energy (flushing) can accelerate this process. By hydraulic flow reduction they extend the time required for such sludge to be eventually be reduced. The description fits Sapropel and the impact of organic decomposition is noted in the report below.

“Particles of decomposing organic matter created blankets of sludge that consisted of a homogeneous, black, plastic material with a strong, unpleasant odor.”

Sapropel as it ages also naturally complexes metal ions, so it is not uncommon to find elevated metals in them. Some of the first research (EPA 1982) looked at Sapropel as a natural process for metal remediation processes.

After 1972 the public policy debates of controlling pollution – often “manmade” soon eclipsed natural conditions of forest cover, temperature and energy pathways. But high heat and natural organic loadings does influence nutrient availability and habitat change in Long Island Sound now linked to seafood abundance. The nitrogen input TDML discussion for example needs to be broadened to include climate patterns. Although the public and environmental policies of the last half century has placed most of the pollution emphasis upon “us” as the chief modifiers of coastal environments when in fact a long term environmental review is much less clear. That’s why we need to look at the Saprobien System and the impact of Sapropel to fish and shellfish habitats. This review may shed some light on natural habitat factors first identified in the 1950s and 1960s as Sapropel formed.

“During anaerobic conditions particularly in summer, organically rich sediments may decompose to form Sapropel. This is a blue – black substance containing hydrogen sulfide and methane. It has been suggested that fossilization of Sapropel results in the formation of oil.” (Pg 40, The Ecology of Inland Waters and Estuaries Reid 1961).

When temperatures rose and energy levels decreased estuaries soon became Sapropelic and within decades Sapropel would become a dominant habitat type. One of the signs of Sapropel in hot weather is the smell of sulfur or “stinks” a mixture of methane and sulfides that many reports refer to us the “rotten egg smell.” Sapropel – rich in nitrogen compounds was used as fertilizer for hundreds of years. Its formation and function as nitrogen sink needs to be included in Long Island Sound studies.

A question remains if we gave natural climate patterns a free pass when it came to habitat succession and nitrogen levels.

Always welcome suggestions, comments. I can be reached at tim.visel@new-haven.k12.ct.us

The following appendix is excerpts from Blue Crab reports (2013) some include discussions of Sapropel.

The Search for Megalops – Program Report #1
2013 – Blue Crab Year
April 17, 2013

Could the 2013 blue crab year answer climate change habitat questions?
At the turn of the century winter flounder fishers and bay scallopers found disappointment in many Connecticut coves and bays. Following the cold and storm filled 1870s the 1880s and 1890s were much warmer and then very hot. The 1896 and 1898 heat waves in New England were record breakers for their time. Bays and coves turned black and began to smell of sulfur, the rotten egg smells so common along the shores. Besides the Blizzard of 1888, the Portland
Gale of 1898 (most likely a November hurricane) and two gales of 1903 and 1905, the 1880 to 1920 period was relatively quiet, storm free. But with this period came heat waves that killed hundreds of people. National Public Radio NPR has a comprehensive report on the career of Theodore Roosevelt during The Great Heat Wave of 1896 in New York City. The eastern CT fyke net fishery for winter flounder had largely failed by 1910 – bay scallops were practically nonexistent.
But fishers also noticed some distinct habitat changes then; eelgrass which was almost cleared completely out of the coves by the 1870s storms was back and formed huge dense monocultures (meadows), Brant feasted upon this eelgrass and populations of Brant soared as conditions now favored lush eelgrass growths. Eelgrass meadows trapped organic matter, not disturbed by storms which then rotted and turned black in high heat. Oyster fishers at the time complained the most about these “new habitat conditions” and the first reports of ruinous black “mud” came from Great Salt Pond research in Rhode Island (1898) and the work of Rhode Island Experiment Station run by Dr. G. W. Fields. Organic matter washed into streams with manure, a dairy industry practice then and formed a slurry of rain driven organic oatmeal that buried previous “hard” bottoms and now were soft and sulfur smelling which killed river oyster beds. In the high heat this organic material started to rot and produce hydrogen sulfide, as recorded by the coastal residents who reported the “marsh stinks” the infamous rotten egg smells. That happens today also, and surprisingly Niantic Bay, Connecticut had a brush perhaps with hydrogen sulfide toxicity in August 2009. Then newscasts WTNH-New Haven contained reports of blue crabs crawling on land to escape the “low tide” Niantic Bay (River) waters with pungent smells. (Blue Crabs Picking Land Over Niantic, Friday August 7, 2009 by Jamie Muro). I believe this to be similar to more southern crab “jubilees” when blue crabs walk ashore by the tens of thousands. The August date and very hot temperatures suggests a hydrogen sulfide toxic “event.”
When coves turned black, sulfate reduction processes accelerated and fish kills soon followed- that was the 1890s. These conditions persisted into the 1920s (Grabau 1921).
But as oyster fishers complained about black muds, lobster fishers also watched as their fishery collapsed, and the lobster die offs peaked between 1898 and 1905. Bay scallopers also were out of business, not from overfishing but because instead of cold water coralline reds algae and red weed (thought to be the real scallop grass) such as the deep water Narragansett bay scallop habitats were now covered with eelgrass and in high heat acidic conditions were lethal to bay scallop sets (dissolves shells). But as the bay scallop, lobster and inshore winter flounder fishers saw disappointing catches, those blue crabbing, catching soft shell clams, striped bass, and those involved in oyster culture on hardened bottoms were reporting very positive increases catches couldn’t be better. And for every acre of oyster and clam shells placed on aquaculture acreage, it buffered acidic marine soils for hard shell clams while creating more habitat for winter flounder.
The year following the Portland Gale, the Connecticut oyster set (1899) was to be the set of the century, soft shell clams set heavy on Cape Cod, blue crabbing soared region wide north even into Buzzards Bay and during this heat, striped bass grew huge. Many Connecticut River clammers converted their skiffs into guide boats to take New York hunters duck hunting in Connecticut River marshes no longer iced in as before, and now early “hot” springs made duck hunting and turtle trapping the business of necessity not choice. Noank, once of the center of Connecticut’s lobster fishery became a community of coastal cottages and the place to “torch light” blue crabs at night. Striped bass fishing became a popular past time for the then rich and famous. Many northern islands walking fishing “stations” were build (few storms) and the bait used to catch some of the largest stripers then that would be 2 pound lobsters or soft shell blue crabs. Fishers and hunters were in “The Great Heat,” a period in New England’s climate history of very warm hot summers and few strong storms. If you were to examine the lobster and blue crab fisheries today besides habitat quality indicators that are present today they will provide some answers to habitat questions asked over a century ago. What happened to the Southern New England lobster fishery in 1898 and a century later Connecticut again has experienced a lobster die off while an amazing surge in blue crabs. Why?
These habitat changes were signaled in both cases by the fisheries noticing bottom habitat changes, the muck that covered so many estuarine bay bottoms, and produced those sulfide smells, today that muck is called Sapropel and is the largest indicator we have to habitat reversals and fishery transitions. Fishers in New England wide raised the Sapropel alarm bell in the 1980s and looking back they were correct to do so. In one of the few case histories of this sulfur rich mud impacting fisheries could be the Long Island duck farms of the 1950s and 1960s. The appearance (or disappearance) of Sapropel may become a key indicator of climate induced habitat change. That case history is under review presently.

All About Sapropel – and Habitat Questions from Western Connecticut Crabbers

In July 2011 we had a large die off of adult blue crabs in western CT during a heavy rainstorm. It was hot; also a time of heavy West Nile reported chemical pesticide and reported application of brickets into street drains. A large migration of crabs had already left the Housatonic River and was heading east, and western Connecticut crabbing had been excellent following another great 2010 year. After the heavy July 2011 rain event, many western crabbers noticed a significant brown coloration to the water. This brown color is linked to the breakdown of oak leaves. Tannin, an acid, is very high in oak leaves. Some reported that the waters also “smelled” badly like sulfur. This hydrogen sulfide smell is attributed to coastal bodies of water and salt marshes in late summer when dissolved oxygen is at its lowest point. Bacterial processes in high heat and low oxygen tends to reduce organic matter (leaves) by bacterial reduction of sulfate releasing the hydrogen sulfide gas – thus the foul or rotten eggs smell. This smell (stink) was prevalent in the later stages of The Great Heat a century ago and noticed by coastal residents near marshes. That also occurs today and many coastal residents can confirm this late summer event. The rainfall may have dislodged rotting leaves increasing levels of hydrogen sulfide in tidal areas. The same areas that had been so productive for blue crabs can lead to high sulfide levels and might trigger these large late summer migrations.

Warm waters and few storms helps the blue crabs habitats but as with the lobsters, great catches are made just before a habitat crash – and the blue crabs in Connecticut might be facing a similar tipping point – an almost forgotten hydrogen sulfide toxicity in the water itself. This is due perhaps to the buildup of black sulfurous mud called Sapropel. In warm weather leaves and organic matter rots and produces Sapropel. It accumulates rapidly with few storms to wash it out it can reach several feet deep – locally it’s called Black Mayonnaise, and is often a dominant habitat type. Not too much is known about the extent of Sapropel deposits in Connecticut. Key scientists worldwide were looking at it just after The Great Heat 1880-1920, and had convened a world conference about sulfurous mud just prior to World War II. The conference (1938) papers were eventually printed in 1958 but by that time we were in the period of cold and numerous storms, the North Atlantic Oscillation. Estuarine habitats had reversed - Sapropel deposits were washed away and from bays, coves and salt ponds, and a new habitat type, estuarine bivalve shell now became dominant. Winter flounder was enhanced by firm bottoms estuarine shell, while blue crabs which need the Sapropel to burrow into during the winter – for long hibernation periods retreated -mostly and today to rivers and dredged channels. The onset of a habitat reversal had “helped” some species increase – up to a point. That seems to be the case with Sapropel, and now perhaps blue crabs.

In a Cape Cod study in the middle 1980s, a diverse habitat type produced the best diversity or biological richness. The observations included one quarter, hard mud, or sand, one quarter estuarine shell, one quarter vegetation, and one quarter small stones (or cobblestones) were the richest habitat areas in terms of biological diversity. When one habitat type dominated total abundance often remained about the same but diversity declined. A dominant habitat type – all yielded some organisms- except Sapropel. This habitat type tended to reduce diversity and in large deposits was vacant of most recognizable animal life forms.

Sapropel did contain eels and eelgrass together; it was felt to be important to habitat requirements of overwintering Blue Crabs who needed to hide from predators during long winter hibernation. It was, however, a limiting habitat type and in large deposits devastating to most shore life, fishers often reported accumulating leaves first - the material that creates Sapropel. Oak and Maple leaves are naturally acidic and in poorly flushed coves and bays collect and rot in summer heat. This is the material that so many kayakers experience (not pleasant and often dangerous) in shallow warm waters. When oxygen levels normally lower in warm water, this organic matter cooks – rots as terrestrial compost- but here the reduction processes create a perfect storm of habitat failings or constituents, sulfuric acid, hydrogen sulfide, ammonium and now removes all oxygen. One long time winter flounder fisher, Louis Bayer, from eastern Connecticut (1980s) watched as his favorite winter flounder habitats were covered with “black mayonnaise” and once commented to me “this stuff is bad for fish” – I quickly agreed, it was.
In some bays Sapropel has past 25% coverage to as high as 50 % to 75%. Previous core studies do show episodic events in coves that have core samples layered then mud with estuarine shell. These habitat reversals could have happened before, many times in Connecticut’s fisheries habitat “history”.

In the late 1970s Sapropel seemed to increase along with Blue Crab increases – There appears to be a habitat connection with older blue crabs which tend to seek out these soft deposits in winter, but in late summer Sapropel becomes deadly. The compost residues from Sapropel has a role in acidification of estuarine soils – bivalve shell erosion, lowering oxygen and in the presence of ammonium which fuels brown algal blooms and hydrogen sulfide a lethal one-two knockout punch to many organisms we as a society value. Sapropel is now linked to the tremendous increase in necrotic fin rot disease in winter flounder populations during the same time, and an increase in the plant nutrient ammonium which favors the harmful brown algal species (HAB). HAB blooms have been shown to reduce bay scallop habitat quality.

As habitat quality for Blue Crabs increased, winter flounder habitat quality declined. Sapropel may even trigger mass movements of Blue Crabs by the presence of hydrogen sulfide levels in the water itself. That movement has happened the past three summers- although the 2011 “waves” were weak following a much colder winter, blue crabs could be moving to avoid hydrogen sulfide toxicity.

The Search for Megalops
Megalops Report #5

July 15, 2013

The 2013 Blue Crab Year

Increased Rainfall, Heat and Sapropel Habitats

Black mayonnaise (Sapropel) has been attributed to declining inshore fish, and shellfish habitat quality (Boston Globe article, 11/26/11) and accelerating nitrogen pollution Conservation Law Foundation report 10/30/2011. Coastal residents in many southern New England states now reference it as bottom changes. Its cyclic buildup is part of a natural process now linked to shedding excess nitrogen – ammonia compounds during high heat. The changes in bottom habitats in the 1980s were first observed by fishers, and necrotic fin rot, in winter flounder. Shell fishers then noticed declining bivalve sets and changes in bottom pH and smells would be minor to the enhanced sulfur reduction/nitrogen storage processes people couldn’t see. The increase in sulfur gas would be associated to the “marsh stinks” a century ago. In recent times, the hydrogen sulfide gas of low oxygen reducing environments would create long periods of low oxygen and under the proper conditions create hydrogen sulfide “fish kill” toxic events, the “black water death” of the last century. But, Sapropel buildup is not a new occurrence and many of the first layers of Sapropel were found beneath eelgrass meadows. There are two basic types of Sapropel, forming and ancient. Sapropel can occur in cycles (such as today) much lower amounts from storms that tend to wash it from coves (see Megalops Report #3, June 12) or warm storm free periods in which it tends to accumulate.

Ancient Sapropel is found in deep marine seas and the bottom of lakes. It has over thousands of years become a organic rich high nitrogen material that when applied on farm fields especially cereal and vegetable crops can increase crop yields 30% to 75%. (Reference Lakes Bottom Deposits and Their Economic Value In Industrial Agriculture Sector Off Western Siberia 2011; Tatiana N. Serebriakova, Ph.D. or et al. University of Connecticut). Sapropel is now recognized worldwide for its ability to bank or store (sink) nitrogen compounds. This ability has not gone unnoticed and Sapropel has caught the attention of a growing worldwide organic natural food constituency who consider it to be a natural formed fertilizer supplement for artificial ones.

Most Sapropel forms at the deepest most oxygen deficient areas of lakes and ocean basins. The absence of oxygen is a key ingredient for Sapropel formation. But in the marine environment in high heat Sapropel becomes deadly and zones of oxygen depletion often have soft Sapropel bottom deposits. A shallow water estuary can often have sea grass (eelgrass) environments important to blue crab and other crabs species over it. It is a habitat type that can be influenced by rainfall. Large amounts of organic matter such as sticks, bark, leaves and dead grasses washing into shallow warm estuaries quickly can rot and decrease water exchange. Sapropel tends to absorb heat; soft patches of it with eelgrass were significantly warmer than sandy clear areas in surveys of Niantic Bay in the 1980s. In areas of “black mayonnaise” it was hot and seemed to drive colder-preferring species away from it. Many blue crabbers experienced Sapropel and most likely did not realize it at the time. It can get deep in slowing moving current flows in shallow areas. Several kayakers have had some close calls as well, believing bottoms to be firm only to find themselves stuck in “soupy black muck”.

Sapropel has the following characteristics: it is acidic, black, jelly-like and often feels greasy to the touch. When disturbed it has a slight sulfur (match stick) odor and will, because of its low pH, quickly stain your hands. Because of its high sulfur content it is now suspected to be the source of the yellow coloring of the older yellow faced blue crabs (perhaps from overwintering?). In high heat Sapropel can be damaging in many ways; it can shed ammonia during sulfur reduction processes, a brown (HAB) algal nutrient. It produces both hydrogen sulfide gas (the marsh “stinks” of the last century) and sulfuric acid, and removes any oxygen for organic respiration in contact with water. Because of its tendency to form a jelly-like substance, it tends to collect in slow moving currents away from direct energy pathways; it can be found in the quiet upper reaches of coves and bays.

Fishers first noticed Black Mayonnaise in the early 1980s – especially bay scallopers. The increase of black mayonnaise was very alarming to the Hyannis Bay fishers on Cape Cod in the early 1980s as they had never seen it before become so thick so fast. Fishers who fished in Lewis Bay were the ones to correctly identify its source as deep brown waves of organic debris (sticks, stems, dead grass) – called oatmeal which in high heat turned black. In times of heat, a sudden rainstorm (or storm for that matter) could disturb these putrefied deposits releasing hydrogen sulfide and causing the large fish kills (black water deaths) from the past century. It was the Cape Cod fishers who found in places several feet of organic oatmeal that would turn black in August heat (1983).

This is the same oxygen deprived substance that collects in closed system aquaculture systems and makes changing filters (which also turn black with the same sulfur odors in them) in restricted air spaces so dangerous. The toxicity of such Sapropel formation and toxic hydrogen gas would cause tragedy at the University of Maine with aquaculture technicians (July 2002). Sapropel and the toxic sulfide formation can be very deadly not only to sea creatures but to us as well. (See Bangor Daily News July 31, 2002 – A sealed Aquaculture System used to recycle water for Halibut culture experiment had tested positive for hydrogen sulfide. The sludge had built up enormous hydrogen sulfide levels in the organic matter and when disturbed released toxins heavier than air that smell “similar to rotten eggs”.)

The increase of Sapropel coverage of estuaries is the largest indicator of habitat change in the past century. The fishers on Cape Cod in the 1980s were right to be concerned about the formation of Sapropel, it would go on to devastate the bay scallop, quahog and winter flounder habitats within a decade. The increase in Blue Crab habitat quality was just beginning but as Sapropel accumulated its impact upon blue crabs would be accumulated by heavy rains – it is those times that hydrogen sulfide is washed from it – the black water death of the last century. Heavy Sapropel layers can be damaging to blue crabs as well. The heavy rains this spring could influence habitat quality into negative areas for the blue crab and we may have seen that happen in July 2011 – western Connecticut.

Lobster and Winter Flounder

If organic composts (Sapropel) is a key link to habitat reversals we should look to other species.

Sapropel and a fungus Saprolegnia is now linked to the winter flounder fin rot disease of the 1980s. And what locations showed the first signs of fin rot, they would be quiet coves and in low energy areas in which black mayonnaise first collected. Organic material is rich in bacteria and fungus and some of the first concerns come from lobsters caught over sewage sludge at the 105 mile off shore New York dumpsite. At the 1977 Rhode Island Fishermen Forums (once sponsored by Rhode Island Sea Grant), Jake Dykstra held up lobsters caught from the 105 mile dump site with shell disease. I had started lobstering in Long Island Sound in 1967 and had never seen anything like that. By 1982 the New Haven Harbor was showing winter flounder caught in the Morris Cove section had fin rot in 22% of the sampled winter flounder. It is a low energy area and offshore surveyed areas in higher energy zones at the same time showed much lower prevalence . (I Incidence of Fin Necrosis In Winter Flounder, Pseudopleuronectes Americanus (Walbaum), from New Haven, Peter J. Auster, The University of Connecticut Marine Sciences Institute, Marine Research Laboratory, P.O. Box 278, Noank, CT 06340. Report to Schooner, Inc., 60 South Water Street, New Haven, CT 06519 1981 )
In high heat both fungus and bacteria thrive and in low oxygen marine environments this compost (black mayonnaise) quickly becomes Sapropel.

In the New England lobster fishery, shell disease first occurred historically in lobster pounds – enclosures in tidal creeks and salt ponds in which lobsters were “wet stored” like cattle pens to be sold at high prices in times of short market supply. These “pens” held lobsters for several months and fed, as usually poorly flushed bacteria and sludge soon built up on the bottom of these storage areas (personal observations, 1977). Bacteria in warm weather thrived and massive August lobster pound mortalities are documented in the fisheries literature. What was happening in a small habitat way would soon impact all of Southern New England, as energy (storms) slowed, and organic matter rotted in high heat – what Peconic Bay and Great South Bay fishers described to me decades ago – bay bottoms just turned black and went soft. With increasing heat into the 1980s, Sapropel deposits grew in poorly flushed coves, a habitat failure occurred first for winter flounder and later for lobsters. A key ingredient it seems was warmth, the warmer waters to the south had higher incidence of lobster shell disease than cooler waters to the north (Cobb Castro 2006).

Shell disease hit lobsters hard in Buzzards Bay in 1997, but stopped short of Maine waters (thought to be to cool). In 1998 the incidence of shell disease soared in the southern New England region as lobster stocks crashed. Shell disease is still with us – as the next section illustrates.

For more information about Sapropel, see “Sapropel and Climate Change – Fisheries Habitats Degraded by Putrefied Organic Debris in High Heat, Low Energy Conditions” available from the Sound School Adult Education program. Contact Sue Weber (susan.weber@new-haven.k12.ct.us).

The Search for Megalops
Program Report #7
August 16, 2013
The 2013 Blue Crab Year

Western Connecticut Blue Crab Habitat Failure and Recovery
One of the most interesting aspects of the natural ecology of embayment systems is balance, and the other is ecological voids. Nature hates a vacuum and that is true, but what takes years to happen can be gone in an instant and what happens instantly can take years to restore, in other words, we have habitat succession in the marine environment also.
One only has to look at terrestrial forest fires and marine hurricane impacts to experience this change. But what about the habitat succession; we can’t see, we can see the impacts of beaches swept away by storms but will we see the kelp/cobble stone forests that often follow? Forest fires are terrible events for those in its path but years later species that needed grassland habitats thrive, while those that needed the forests before decline, a balance between habitat types and the populations that need each type? Do we know enough about habitat succession and population dynamics of marine fish and shellfish in the marine environment? No, absolutely not, we haven’t even begun to understand it or study it for that matter. We learn about marine habitat succession from fishers, as we did first about terrestrial succession from hunters. Similar to terrestrial habitat succession, (drought and high heat precedes forest fires, while rainfall signals a long term renewal of the forest). Marine habitat succession is governed also by energy and temperature.
Hunters would head to grasslands to seek species that needed that habitat, fishers head to “structure” to catch species that need it. Talk about structure to any freshwater bass fisher, and you will soon find they are keenly aware as to the value of structure to overall fishing success.
But what about blue crabbing, what made the 2006 to 2011 blue crab populations soar in western CT? What do they need, what is their habitat balance in regards to habitat succession? These are questions that need answers if we are truly to understand one of the largest habitat reversals in a century.
Did western CT blue crabbers experience something of a habitat successional event in 2011, yes I believe they did.
Hydrogen Sulfide And Its Impacts Upon Estuarine Health
Sapropel and western CT river life systems may provide response to western CT blue crabbers. The truth of the matter is that we just don’t know much about sulfide toxicity in western CT. It is an area of research that is lacking even into today.
In many respects my response to questions from the western crabbers in 2012 is a combination of several factors low oxygen, freshwater toxicity, chemical toxicity, hydrogen sulfide toxicity and disease.
While all of these factors should be considered, I believe low oxygen/hydrogen sulfide toxicity to be the primary reason for the apparent habitat failure. Many blue crabbers pointed to the West Nile treatments and that deserves a look and I did issue a special report (Pesticides and Blue Crabs on July 24, 2012) about this, I also looked at disease and habitat life cycle stressors including oxygen and chemical factors as contributing causative disease factors, but central and eastern blue crab populations remain to my knowledge relatively disease free. So I looked at a key concern of mine the habitat impacts of high heat, low energy and high organic deposition, particularly leaves oak and maple as acidic sulfur respiration pathways leading to hydrogen sulfide buildup and fish kills.
And, as I usually do, I look at what is in print, in the historical records and current research. After researching the problem for about a year in regards to western CT rivers and harbors, I found very little written about the impact of deep deposits of organic matter (leaves). And when pollution of rivers did grab a national attention here in the US, its focus was upon the chemical manmade aspect of non natural “polluting” substances, entering water courses not natural ones such as organics, leaves for example. A consensus upon pollution would itself contain a biased point of view, how could something “natural” also be considered a pollutant. This public policy component would initially tend to the analytical chemistry descriptions of measures for manmade substances for pollutants.
When examining the historical records it is important to recognize a resource bias in the scientific community at the turn of the century. During this period lakes were the resource of concern, still important for water powered machinery and drinking, however rivers or harbors were not high on the priority list. In fact, rivers were thought to be the best way of “receiving” factory wastes, so it was much to our repugnance a “reasonably use” of pollution policy existed. Until well into this century, one only has to read the three hour speech to the CT Agricultural Board in 1886 about pollution which the editor of the Hartford Courant, then Mr. J. B. Olcott described walking along the Quinnebaug River with cotton soaked in glycerin stuffed into his nostrils to block out the smell from the river. Not doing so would accordingly cause one to instantly wretch. This was a common practice during this time in Connecticut unfortunately along many riverfront factory communities. Therefore, is it not surprising that some of the earliest river studies of the biological impacts of river organic matter pollution came from Europe and not from the United States. Some of the first studies are from the Baltic region, especially Germany and Poland. River fisheries were very important in Europe (fisheries, drinking water) so impacts to them were first studied and the first research on the impacts of high organic matter is from them. The first formal study of putrefied organic matter, and biological impacts upon rivers was developed by Kolkwitz and Marsson at the turn of the century. In 1909, they developed what they termed, a Saprobien system for the assessment of organic pollution, and in the 1950s, 1960s and 1970s this bias (chemical not organic pollution) for lakes and not rivers continued here in the US. In the 1930s a worldwide conference about Sapropelic formation was held and at the urging of Parker D. Trask of the US Geological Survey just prior to World War II, the paper of recent Marine Sediments was finally printed in 1955. In 1971, H.B.N., Hynes of the University of Waterloo, Ontario, Canada, published his now famous book, “The Biology of Polluted Waters” (University of Toronto Press 1971) he mentions this bias in regards to the “well known” classifications of Saprobien System for rivers. “But perhaps well known is too strong an epithet to use because although it is widely used on the Continent, it is rarely mentioned by American or English authors.” The Saprobien System as defined at the turn of the century will be recognizable as a slightly different system for lakes today, not rivers. And the largest constituent of Sapropel in CT now appears to be leaves, and depleted oxygen (warm water) conditions – “a habitat history” or much longer cooler and then warmer periods.
The basis of this classification system is the theory that when a river system receives a tremendous load of organic matter (leaves, grasses, bark, twigs, etc) it would result in a series of “zones” of decreasingly severe conditions for plants and animals downstream. A brief description of the Saprobien System is below:
PolySaprobic – Zone of gross organic pollution organic matter with little or no dissolved oxygen and the formation of sulphides (now sulfide).
MesoSaprobic – less organic matter and grades according to the numbers of indicator life forms
OligoSaprophic – The zone of recovery where the mineralization (breakdown) of organic matter is complete and oxygen content is back to normal and a full range of plants and animals occur.
In simple terms, western Connecticut rivers and estuarine areas could now be termed PolySaprobic, favoring the condition of sulfides and extremely toxic to blue crab Megalops and adults. It is now strongly suspected in the black water deaths (largely fish kills) at the turn of the century. It is suspected that floods following years of hot stagnant conditions ripped open Sapropel deposits (black gelatin) releasing enormous quantities of sulfides causing massive fish kills, by “black water” usually accompanied by strong sulfide rotten egg” smells. Passive deposition of leaves and organic matter in coves in Eastern CT such as the North, Middle and South Coves in Essex in which oak and maple leaves have collected are good examples. Over decades in areas even 10 feet in depth have layers of leaves, the western Connecticut rivers may have received just as much organic matter by active watershed transport, organic matter from storm water, and ripped into “brown bottoms” of organic oatmeal in just a few days.
I believe that is what the western Connecticut crabbers were trying to tell me in July 2011 (see Report #12, August 2, 2011; Report #14, August 19, 2011) that heavy rain had ripped into sulfide deposits killing crabs in place. Irene may have brought down additional organic compost then followed by Sandy. The sulfides now released by these organic deposits (warm water and less oxygen favors deadly Sapropel deposits) which lower pH levels could have resulted in a western Connecticut die off of blue crabs not seen here for a century. I will also add that lower pH tendencies to increase the toxicity of insecticides as detailed in label warnings. Many insecticides have both high heat and low pH application warnings.
In simple terms, it is as if someone dumped overnight 5 feet of compost on your yard, the lawn would quickly die, you could see it, and until it is raked off, no lawn. The same thing happens in the marine environment, usually not as dramatic as floods carrying down decades of built up watershed organic matter at a time, but a gradual build up as temperature rise rot. In this case, rotting leaves may have covered valuable blue crab habitat.
In periods of cold (more oxygen in water) and frequent strong storms Sapropel accumulations “melt” away as storm activity washes it from tidal areas. Several western crabbers have asked me about Sapropel (after Report #5) and many blue crabbers have seen it, but know it best by its common name, black mayonnaise. It is also in the location of blue crab populations making its toxic impact, event (storms and hot weather) temperature related. Organic deposits with sufficient oxygen (cooler water) seems to be a good blue crab habitat type but very deep deposits in hot weather tends to be Sapropel. That explains to some extent hot weather warm water blue crab jubilees down south or here in New England late summer and the turn of the century black water deaths. One of the most notorious black water deaths from the last century occurred on Long Island, New York in Moriches Bay between July 29 and August 4, 1917. Here tens of thousands of winter flounder died and then putrefied in the heat. Although today very little is written about Sapropel itself, in Southern New England from Cape Cod to Long island, in shallow warm coves and bays, with reduced tidal exchange, it has often become a dominant habitat type. It is in hot weather Sapropel is toxic to most forms of requiring oxygen marine life and sheds ammonia, a brown algal nutrient.
This also explains how great blue crab habitats such as those in pre July 2011 habitats quickly turned deadly for blue crabs resulting in a DIP “dead in place” blue crab observed die off.
More about Sapropel and Saprobien System in later newsletters.