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« on: October 12, 2021, 12:25:15 PM »

IMEP #97 Part 2
Estuarine Cores Records Harmful Algal Bloom History
“Understanding Science Through History”
Climate Change and Red Tide – The Mumford Cove, Groton, CT
A Habitat Case History - January 2020
Does Sapropel Hold MSX Spores
Viewpoint of Tim Visel – no other agency or organization
This is a delayed report
Thank you The Blue Crab Forum™ for supporting our Habitat History Newsletters
The Sound School, New Haven, CT 06519
(Readers should review IMEP #97-Part 1 posted October 5, 2021)

A Note From Tim Visel

In 1981, I participated in a shellfish survey of Mumford Cove, Groton, CT - the site of a municipal sewage outfall and once a productive shellfishing area.  The survey was arranged by Malcolm Shute of the then Connecticut Department of Health and Edward Wong of Region 1, EPA Office in Boston.  This survey was in cooperation with Dr. Sung Feng of the University of Connecticut.  Rhode Island shellfish officials also participated because of their previous experience in sampling soft shell clams, Mya arenaria, which was reported to be in heavy concentrations along the lower cove edges.  The location of a STP outfall had closed a once productive shellfishing area years before.

The sewer outfall had highly enriched Mumford Cove, including hot weather hydrogen sulfide smells, and blankets of thick sea lettuce now linked the availability of ammonia from urea in the outfall and the bacterial ammonium response of high heat and low oxygen.  The sewer outfall combined with high temperatures created toxic conditions at times.  On Cape Cod (1982 during the same period), thick blankets of sea lettuce were so thick that they suffocated oysters beneath them (John Hammond written communications provided to Tim Visel).  This macroalgae has the ability to change soil chemistry and eliminate other submerged grasses, such as eelgrass.  During the survey, I observed sea lettuce (Ulva) so thick as to obscure the bottom, which made it difficult at times to walk into it – it was that soft.  Clyde L. Mackenzie, Jr. described these conditions in a Marine Fisheries Review article titled “Removal of Sea Lettuce, Ulva spp., In Estuaries to Improve the Environments for Invertebrates, Fish, Wading Birds and Eelgrass, MFR Vol. 67, No. 4, in 2005, my comments (  ).

“Ulva lactuca overwinters as birds attached to shells and stones, and in the spring it grows as thalli (leaf fronds).  Mats eventually form that are several thalli thick.  Few macroinvertebrates grow on the upper surfaces of their thalli due to toxins they produce (these toxins kill blue crab megalops – T. Visel) and few can survive beneath them.  The fish, crabs and wading birds that once used the flats to feed on the macroinvertebrates are denied these feeding grounds.  The mats also grew over and kill mollusks, and eelgrass, Zostera marina.”

The shallow water, nutrient enriched and containing heavy accumulations of trapped organic matter most likely fostered the buildup of sulfides.  This leads to a “composting” marine soil.  Residents and local contacts often reported strong “bad tide” odors in late summer.  This is a segment from a 1982 report, Section B, Water Quality, Town of Groton (Municipal Coastal Program report, Town of Groton, CT, 1982):

“Another estuary in the Groton area is Mumford Cove, which has a number or water quality problems resulting from the presence of a sewer outfall.  The town currently pumps about 4 million gallons of treated wastewater into the cove each day, and a study is underway to evaluate the effects of this discharge.  The addition of this treated wastewater is increasing the rate of eutrophication in the shallow cove, and promoting the growth of seaweed.  Other problems noticed by the researchers and area residents include increased turbidity, discoloration of the water, and an odor.  Increased siltation, which has resulted in poor circulation, is also a problem in Mumford Cove.”  From the Town of Groton Municipal Coastal Program prepared by Raymond Parish, Dine and Weiner, Inc., Hamden, CT, September 1982 – reference “Mumford Cove: Disaster in the Making,” New London Day, October 20, 1981.

Conversations with area residents mentioned that in the 1940’s and 1950’s Mumford Cove was once a popular winter duck hunting location due to extreme growths of “duck weed” thought to be Ruppia maritima – a brackish to freshwater submerged plant.  It is a known forage plant to waterfowl, especially its roots stock.  (See Appendix #6, Food of Game Ducks in the United States and Canada, Martin 1939).

Groton Shellfish Committee members Elmer Edwards, Steve Jones and Ken Holloway were also interested in bacteria tests (both waters and meats) in regards to this waste water treatment plan (World War II) that was expanded in the middle 1970’s.  That plant was constructed during the World War II effort to support US Navy housing.  The University of Connecticut Marine Sciences was researching nutrient levels – Drs Buck and Feng.  The 1981 survey of Mumford Cove (See Appendix #5) was conducted in the summer and first reports back in November 1981 (Ed Wong, EPA memorandum of November 2, 1981 to Tim Visel) included one of the results included red ride cysts were found just above a layer of oyster shell some 1.5 meters deep in some areas that according to Dr. Wong these cysts were still “viable” and biological active.  He summarized that these cysts were deposited at a warmer climate recently (1981) and made reference to Narragansett Bay red tides in the 1890’s – similar coves that had also shown them (locations not mentioned). 

We did find large quantities of soft shell clams in the lower cove adjacent to the entrance of Groton Long Point Harbor- also called Venetian Harbor.  Much of the center of the cove was dominated by deep soft muds and thick growths of sea lettuce, Ulva lactuca.  Oyster (living) populations had long since vanished.  The deep muds when disturbed gave off a sulfur smell and in some locations buried oyster shells were brought to the surface and had iron sulfide stains.

That oyster bed observation agreed with local Groton Shellfish Commission members as well and local stories continued to exist that Mumford Cove was once an active oyster bed.  Conditions I experienced then (1981) did not represent any hard bottom – edges were firm into the center channel areas, which held modest eelgrass growths but the flat portion of the cove was entirely covered by dense mats of the green alga Ulva lactuca.  The bottom would not support walking in many areas.  Commonly called sea lettuce, Ulva is now known to emit a natural biocide. 

The transition from duck weed (Ruppia maritima) to Ulva may have had an impact on the blue crab as well.  Research is now focusing upon toxic impacts of sea lettuce to blue crabs (The Search for Megalops Blue Crab series #3 July 23, 2013).  Donna A. Johnson and Barbara L. Welsh of the UCONN Marine Sciences were looking at dense growths of sea lettuce for toxic impacts to blue crab megalops – their research found that in low oxygen conditions (at night) these plants shed exudates that were toxic to blue crab larvae.  In very low oxygen conditions in one trial (almost no oxygen) all the blue crab larvae died in 13 to 40 minutes.  (Journal of Experimental Marine Biology and Ecology, 1985).  In semi closed systems where flushing is adequate but tidal energy low sapropel may sustain dense growths of sea lettuce.  Sea lettuce growths have now been linked to high pore sulfide levels in soils below them.  In summer, sapropel/sea lettuce growths shed high levels of ammonia – now thought to provide seed habitats for Harmful Algal Blooms of many cysts forming species.  The extreme alkaline content Ammonia has a pH of 13 may protect spores/cysts until a sulfuric flash (event) when this compost is suddenly mixed as by severe storms.  This could create an acid sulfate soil.

Large dense areas of soft shell clams were found in brown sandy edges near eelgrass – occasionally in dense quantities in the southern portions of the cove.  Concerns were expressed by the Connecticut Health Department (Malcolm Shute) about soft shellfish harvesting but soft shell clam relays were occurring on Cape Cod and Martha’s Vineyard (State of Massachusetts Management Plan For Soft Shell Clam Resources In Moderately Contaminated Areas, September 18, 1978).  The Town of Edgartown Massachusetts moved nearly a half-million seed clams (many stunted) with jet pumps into better growing areas. [The use of an outboard power Hanks (hydraulic) rig – (Clams Being Moved To Ensure Growth In Edgartown Project” Cape Cod Times June 19, 1977 could move 50 bushels of adult steamer clams per day – John Hammond – and source of a newspaper article given to Tim Visel, 1983.]

In this article, several soft shell clam relays using a hydraulic dredge commonly called escalator dredges were able to move up to 20 seed bushels per day with a “Hanks Rig” hydraulics (also called escalator dredges) on Martha’s Vineyard moved to clean waters they became the basis of a recreational shellfishery.  (If large amounts of soft shell clams were present they might be harvested as seed).

The disappearance of widgeon grass (Ruppia maritima) was linked to an increase of sewage discharges and reduction of fresh water – primarily by drought.  According to the Groton Shellfish Commission at times Ulva matts smelled (sulfur) and the Mumford Cove was once a popular duck hunting area before sea lettuce appeared (Ken Holloway, Steve Jones, personal communications).  In more saline periods, lower rainfalls do promote sulfate reduction producing sulfides – eelgrass being very tolerant of sulfide could naturally been displaced Ruppia and then itself by sea lettuce.  That is recorded in many Rhode Island salt ponds and bays in the middle Atlantic.  According to several Groton Shellfish members, “Duck Weed” was once prevalent in Mumford Cove and “held the ducks” (Lee, 1980) also mentions similar Rhode Island salt pond habitat circumstances.  If dry hot periods are long enough sulfides could reach levels to those toxic even to eelgrass – including questions about habitat succession of eelgrass over time (temperature and energy profiles) and the role of sapropel formation in long hot dry periods.  It is in the sapropel that red tide cysts were most abundant according to Dr. Sung Fend – often simply termed “fine grain sediment” then.  We may find that sapropel, a sulfide marine compost when exposed to warm water, is a seed bank for cysts that cause Harmful Algal Blooms.

I respond to all e-mails at [email protected].

Red Tide Cysts -

Concerns were raised by Woods Hole Oceanographic Institute about red tide dynoflagellate blooms in Perch Pond in 1979 (Falmouth MA) was G. excavata – not G. tamarensis.  The Woods Hole Sea Grant project had raised concerns about cyst survival in high organic sediments in poorly flushed areas.  Some evidence did indicate red tide occurrence in the Poquonnock River following the regional outbreaks of the 1970’s (reports of Groton shell fishermen).  It was thought at the time red tide cysts lay deep in these sheltered organic deposits (sapropel) and hydraulics (or any storm) could re expose them to potential blooms (Department of Environmental Quality Report – Town of Falmouth Shellfish Department Project) (Communication to Tim Visel, 1982 - Woods Hole Sea Grant Project).  Red tides appeared on the Cape after the Blizzard of 1978 and summer of 1972.

According to Ed Wong, red tide cysts were found in Mumford Cove just above “shell layers” – represented of poorly flushed nutrient rich organic sediments.  This was confirmed by Malcolm Shute of the CT Health Department a few months later (personal communication, T. Visel).  It was thought at the time that such poorly flushed areas (slow tidal flows) were sources of red tide cysts after heavy storms.  Severe storms could bring them up to the surface again.  Hydraulic transplanting of soft shell clams from Mumford Cove was immediately tabled. 

In 1983, I informed members of the Groton Shellfish Commissioners of the presence of red tide cysts for further possible study.  We looked for oyster shell layers but could not locate any (1983 to 1984).  According to local shellfish commission member accounts oystering in Mumford Cove ended in the mid 1930’s.  The presence of the viable cysts in Mumford was somewhat alarming – it was thought that organic acids could have destroyed the cysts coating or sulfides deep in the sediment was toxic to them as well (during the Mumford Cove shellfishing survey sulfur smells were often quite strong).  Many of the soft shell clams sampled shells at two feet deep on the exposed bars crumbled easily from acidic erosion (T. Visel, personal observations).  No oyster shell layers were observed in any the test sites I examined in 1981 or UCONN Sea Grant surveys 1983 or 1984 that followed (pipe penetration tests).  The ammonia levels in sapropel composts are now connected to protecting these red tide cysts – that is how they could be so deep in the sapropel and once exposed may be released by the presence of oxygen and the formation of sulfuric acid.  (suspected to be a storm event – T. Visel).

Environmental History – Mumford Cove

Mumford cove lies within the Town of Groton, CT and is the remains of drowned lagoon.  Weak ebb flows cut a storm-driven sill, between a large barrier spit system southeast at Groton Long Point – a smaller barrier spit in on the western cove.  It was mentioned that dredging projects followed the 1938 Hurricane.  The cove has an open exchange to the Long Island Sound but is susceptible to storm events according to local residents the 1938 Hurricane drove a wedge of sand deep into the cove.  It has never been a deep water anchorage but a salt pond was dredged (Ford Canal – Venetian Harbor) part of the Groton Long Point community and a second canal north part of the Mumford Cove Association mid point in the cove east side.  Many reports mention first dredging projects occurred in the mid 1950’s.  The cove is surrounded by glacial till (Bushy Point State Park to the east), salt marsh to the north, and a mixture of residential communities on its east shore.  Mumford Cove and Groton Long point communities use Mumford Cove for largely recreational purposes such as boating, fishing.

The Morphology of the Cove was well defined by a Wesleyan University study and is in the attached pages.

Fisheries History –

1870’s – Mumford Cove as many eastern CT coves were known to have had mixtures of estuarine shell/sandy habitats during storm and cold periods.  Local reports mention eel spearing (eels prefer poorly flushed sulfur organics) that supported eel fisheries in winter times.  Local historical societies in the region have numerous accounts of eastern CT eel/spear fisheries in these soft bottom coves.

The mid Atlantic – New England historical fisheries are filled with accounts of winter ice spear fisheries for eels.  And is most likely the reason why eelgrass got its name – the sapropel eelgrass crust in which eels would hibernate or hide during the day protected from the sulfide seeps (smells) that kept large predators away – such as striped bass.  In a winter fishery holes would be cut into the ice on such salt ponds and coves over shallow deposits of “eelgrass.”  Spears with hooked tips (not straight) were often called eel gigs (Lee, 1980).  The best spear fisheries were areas of soft organics deep muck – sapropel – with a “live” eelgrass cover some coves such as Alewife Cove in CT were named for the fisheries they once supported and a century ago the most productive eel areas were often called eel river or eel pond for example.  These areas had the soft muck that eels (and terrapins) sought out to hibernate and in periods of warmth – blue crabs as well.  In the historical literature eel spear fisheries mention blue crabs mixing in at times (attempts were made to market speared crabs in New Jersey at one time without success).  Both eels fisheries and blue crab landings often overlap, especially in the New York, Long Island fisheries history.  The open more energy prone eastern Long Island Sound had at times firm bottoms at times soft and Ruppia (duck weed) from core studies.

The Groton Connecticut region in the 1880’s also supported a large winter flounder fyke net fishery – (Smith US Fish Commission, 1889) – winter flounder would return to these coves in spawn in February, March.   

This area of Connecticut was the center of a growing fyke net fishery for winter flounder and the concentration of fykes in this area was among the most important in the country.  H. M. Smith writes in a US Fish Commission Bulletin section on The Fyke Nets and Fyke Net Fisheries of the United States “As already shown, the fyke net fishery of Connecticut is more important than that of any other state.”  The placement of pounds and fykes also is concentrated in eastern CT – State of Connecticut 4th Biennial – Report of the State Commissioners of Fisheries and 1901-1902 Hartford 1902) locates 60 registered trap fyke net sites at the mouths of Eastern CT coves pg 36 – 42. The center of this fyke net fishery was Groton.

Hugh Smiths article about this eastern CT winter flounder fishery is attached but the largest number of fykes were between Stonington and New London (1889) Eastern CT is a high energy zone and prone to the greatest habitat reversals – as evidenced by historic shell layers in these eastern Connecticut coves.  In cooler high energy periods firm bottoms and bivalve shell was prevalent in warm and low energy periods – sapropel (sulfuric ooze) and submerged aquatic vegetation.  Coastal processes continue to shape the cove after storms, change barrier spits or move organic deposits.  Many of these coastal processes have a direct climate signal – warm and few storms tended to seal or reduce flushing – while cold and strong storms had the opposite impacts openings widened and flushing increased.  It is in the latter that sapropel now disappears.

In the late 1980’s, winter flounder fishers reported distinct habitat changes in many of these eastern CT coves especially Waterford coves (hard firm bottoms to soft)).  Many accounts linked the presence of railway causeways as the source of reduced energy and increase in organic matter behind which on August nights shed sulfur smells – the marsh gas “stinks.”  In talking to Mumford Cove residents who spoke to us during the shellfish survey in 1981 mentioned at times horrific smells from the flats – now the center of Mumford Cove (many residents asked if we could do anything about the smells).

In 1991 in response to winter flounder concerns in eastern CT, the Department of Environmental Protection (now DEEP) contracted with Wesleyan University Dr. Peter Paddon to core eastern CT coves looking for shell layers and information on these organic deposits and sedimentation rates.  In the grant award CWF 266-R 7/1/91 to 6/30/93 – Post glacial stratigraphy and rates of sediment accumulation in three small Connecticut coves.  Dr. Peter Paddon includes a habitat history for Mumford Cove which is still relevant today. 

History of Oyster Culture – Mumford Cove

J. W. Collins notes on the oyster industry of CT table 52 – lists both Quiambaug and Mumford Cove as producing 2 to 4 thousand bushels/year of oysters mostly from planted (aquaculture) bedding stock.  Quiambaug Cove and Poquonnock River west was extensively leased for oyster culture but no such records were obtained for Mumford Cove.  The oyster shell layers in Mumford Cove mentioned by Wong (1981) could have been the previous core tests that hit these 1880’s oyster beds.  Mumford Cove was planted by several CT oyster companies including the New Haven based McNeil Oyster company.  George McNeil in the 1980’s recounted visiting eastern CT coves with seed oysters in the early 1930’s about the period that oystering in eastern coves declined.  The location of these aquaculture beds were thought to be in the interior cove center.  According to local accounts the 1938 Hurricane did much to alter the bottom topography and ended oystering altogether (various comments from Groton Shellfishers 1980’s).  Although, Mumford Cove was included in the core study the cove center was not cored only the shores (one core MC-2 near the marsh edge) but black organic deposits extensively mapped – called “black mud facies” however those organic deposits were not cored as well. 

Black mud facies is described by B.W. Flemming A. Bartoloma (2009) as “sulphurous – grey – black mud facies” pg. 176.  Black mud facies is a geology term but biologists know it as sulfuric ooze, sulfate acidic soil or Sapropel.  Although no center Mumford Cove cores were examined in this study – one core was described at the northern edge extreme upper part of the cove as core as core M-C-2 (pg. 23).  “The upper 4 meters of this core is black mud that is bound my plant roots” showing distinct layers of black mud and dense Ruppia roots.  (Cores of the Poquonnock River in a later study grant #CWF-310-R 8/26/93 to 8/31/01 has multiple cores showing distinct shell layers).  The report mapped the black mud facies and the thickest deposits were in the center of the cove shown on Dr. Patton describes the black mud facies as follows, pg. 25, it is also the deposit mentioned by the 1981 Mumford Cove reviews as harboring the red tide cysts.

-From the Patton Study- CWF 266-R

“Black Mud Facies – All of the cores recovered from the open water substrate of the coves contain gray to black mud.  The mud is largely structureless but does contain thin sand layers, particularly in cores taken near the mouth of the coves, for example core QC-3 (Fig. 13).  The sand layers may represent individual storm events but it was not possible to date them or to correlate them for core to core.  These are also occasional mollusk shells and the mud is often bound by the roots of marine grasses, probably Ruppia, for example the 4-m thick mud unit in core MC-2 (Fig. 14).  The mud unit begins at the sediment water interface and can be up to 6m (meters) thick” page 17.

Attachment # 1

Wesleyan University CWF 266-R Post Glacial Stratigraphy and
Rates of Sediment Accumulating in three small Connecticut Coves
Cove Morphology – pg. 8 Patton Study

“Bathymetric maps constructed from surveys conducted in 1991 were compared to the modern charts and to the oldest recorded bathymetric data for each cove. The results for each cove are described below, more detail on each cove is provided by McLoughlin (1992).

Mumford Cove (from Patton Study)

“Detailed bathymetric data for Mumford Cove dates to 1882 (Fig. 3). This bathymetric survey indicates that most of the cove was 2 to 3 feet deep, with the exception of one location, approximately halfway up the cove that was 5.5 feet deep. Subsequent bathymetric maps published in 1887 and 1932 show nearly identical bathymetry, the 1932 chart indicates a central channel that ranges from 4.5 to 5.5 feet deep (Fig. 4). The modern chart shows the channel, dredged in 1950 and again in 1982, which deepened the natural channel between 7 and 9 feet and extended the channel to the head of the cove. Our 1991 survey does not differ from the 1982 chart (Fig. 5). The bathymetric record shows that there has been little change to the depth of the cove over the past 100 years with the exception of the dredged navigation channel.

The historic charts do indicate changes to the western shoreline. An 1847 chart of Fishers Island Sound shows the existence of sand spilt built eastward into the cove from the rocky headland of Bluff Point. By 1882, this spit had been eroded and in its place was a small marsh island that was still present in 1934. In the past 50 years a new spit has built eastward from Bluff Point and has prograded across the position of the marsh island. At low tide, salt marsh peat crops out in the swash zone of the spit, revealing the position of the now buried island. Aerial photographs of the cove also show that the mouth of Mumford Cove is a broad shoal consisting of a complex of sand bars, similar to swash bars at the entrance to coastal inlets. This shoal limits the water depth at the mouth of the cove which, in the absence of the dredged channel, would be approximately 2 feet deep at low water.”

It is evident from US Fish Commission reports (Smith 1889) that area habitats were once conducive to winter flounder and Collins (1880) to oyster culture.  The sediment/sapropel conditions surveyed in Mumford Core no longer provided hard bottom habitats for oyster culture.  No relic or surviving oysters were found in a University of CT Sea Grant shellfish survey in 1983 (Visel, Holloway), nor a 1985 review of oyster setting.  (Test shell oyster spat bags were set along the main channel in the harbor at Groton Long Point – no oyster set was recorded).

Red Tide Cysts were found in 1981 and reported by Maranda et al., 1985 (Estuarine, Coastal and Shelf Science 21 pages 401-410) to be in Mumford Cove Strain (Isolates #CIC-2) and by Anderson et al. in 1982 (Estuarine, Coastal and Shelf Science 14-447 to 458 and the CT Health Dept Malcolm Shute in June 1985 (The Day Newspaper June 21, 1985) “State Health Officials Urge lifting Groton Shellfishing Ban” as levels had dropped to 44 micrograms of toxin for 100 grams of shellfish meat – below the recommended level of 80 micrograms.  A red tide bloom was reported in Palmer Cove east of Mumford Cove in 1983.  The prohibition (1981) upon hydraulics dredging for shellfish in Mumford Cove continues by the CT Dept of Agriculture Aquaculture Division, which is also attached (under abstract phytoplankton monitoring.)  The presence of red tide cysts could be a valuable tool in climate change studies, we have in Mumford Cove one of the largest accumulations of Sapropel – indicated by oyster shell habitats of the last century and reports by US Fish Commission reports for winter flounder that includes Mumford cove by name and date.  We know when the bottom was firm enough to support oyster culture from US Fish Commission records, see appendixes.

The location and depths of sapropel (black facies) in Mumford cove raises the question of eelgrass succession that it being more tolerant of sulfides than Ruppia (Widgeon grass or duck weed) – hunters tell me that ducks ate this SAV along the coast years ago.  The presence of Ruppia in the cores from the Mumford Cove, (Patton study) also indicates that at times Mumford Cove may have had species reversals connected to habitat succession – governed by changing climate conditions.  Habitat types do change and sapropel/eelgrass compost have been linked to sulfide purging and huge ammonia generation.  These two toxins may influence eelgrass growths, which lock these composting deposits in place – with viable red tide cysts in them perhaps released by storms.  Researchers are examining these events as they relate to fish and shellfish abundance and the successional attributes of eelgrass itself.  The most important aspect might be the level of pore water sulfides in eelgrass soils in Mumford Cove, below which is a possible red tide HAB seed bank.

In 1987, the sewage plant outfall discharge was removed from the head of Mumford Cove following lengthy legal negotiations.  Summers continued to warm to excessive heat and sulfide ammonia levels most likely increased.  Eelgrass returned to the cove but since Irene and Sandy the cove morphology may have also changed as they have in the past.  Would Mumford Cove support oyster culture today – it might – a return to the sub-zero 1870’s when cold and storms dominated our climate, perhaps that is when Long Island Sounds cold and stormy period gave rise to the Sounds nickname by maritime interests.  During that storm filled and bitters cold climate period they called Long Island Sound – “The Devils Belt.”  These coves then had firmer bottoms.

After Hurricane Gloria 1985 and removal of the 1945 sewer outfall in 1987, eelgrass not duckweed became abundant in Mumford Cove.  The question of the removal of 3.5 million gallons per day of aqueous human sewage nitrogen upon the nutrient residence time in Mumford Cove opens the question of two nitrogen sulfur cycles- the short nitrate cycle of readily available plant nutrients dissolved in seawater (oxygen-human) or the second cycle a much longer ammonia cycle – sulfate digestion of organic matter (leaves) by sulfur reducing bacteria (sulfur/sapropel) in heat and low energy conditions (black facies).

The Gary Park sewage plant discharged up to 3 million gallons (or more) of treated sewage per day influencing the salinity flowing from Fort Hill Brook.  Higher salinities would favor eelgrass.  The Mumford Cove watershed is rather limited and therefore cove salinities subject to tides now more than runoff.  The presence of nitrate is a buffer to the sulfate/sulfur cycle and that also impacts sulfate reduction.   The cove is bathed twice a day in seawater rich sulfate and has sulfate – bacteria processes that are linked to releases of ammonia and the source of “rotten egg” odors.

Ammonia levels and sulfide purging are two important indicators for the cycle of eelgrass.  Dr. Feng (1983) as I recall had questions about the nutrient loads into Mumford Cove, and one of the questions of habitat quality related to the presence of the red tide cysts.  That raised larger questions of long term habitat stability and habitat history of Mumford Cove itself - How did the red tide cysts get so deep and where were the missing oyster beds? 

The cycle of eelgrass as experienced during The Great Heat (1880-1920) allowed the expansion of eelgrass in a very warm and low energy period was related to its tolerance of sulfides and high salinity/low energy.  That would put the cycle of eelgrass directly dependent upon cyclic conditions- not us.

The heat (climate) conditions favors HAB cyst release and blooms (also producing cells that form cysts for the next bloom) are the same that favors sapropel formation.  Deep sapropel deposits may hold Harmful Algal Bloom cysts (spores) for centuries – Mumford Cove gives us a look at the fisheries aspect as well.  It is though that the black facies (sapropel) deposits may held a climate record and presence of HAB cysts a signal to previous habitat/climate changes. 

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Appendix #1

In the colder period before 1890, Connecticut’s shallow coves were free of deep sapropel, storms kept marine soils loose and cultivated.  Bivalve shell acted to moderate tannin releases a marine “lime” effect and held clams in the protected coves and bays.  In these cultivated marine soils winter flounder returned to lay eggs and capture fisheries recorded trap fyke net harvests.  Connecticut fyke net fishery in these coves is in several US Fish Commission Reports.



   As already shown, the fyke-net fishery of Connecticut is more important than that of any other New England State.  Compared with 1880, the fishery seems to have about doubled in extent, judging by the number of nets used, although there are no data for 1880 on which to base a comparison of the catch and stock.  The average value of the nets, however, seems to have decreased.  In 1880, the number of fykes reported for the State was 255, valued at $2,480; in 1880, the number was 440, worth $2,230.

Fyke-net fishing is carried on along most parts of the coast of this State.  All the prominent towns have more or less fishing of this kind.  The largest number of nets is found in Stonington, Quiambog, Mystic, Noank, and New London.  The distribution of the fykes in 1889 was as follows:

Town   # of Nets   Town   # of Nets
Stonington    64   Branford   7
Quiambog   110   Milford   10
Mystic   32   Stratford   20
Noank   68   Southport   1
Poquonoc   21   Norwalk   5
New London   54   Darien   7
Niantic   15   Stamford   5
Saybrook   21      

The fish now taken in the fyke nets of Connecticut are principally flounders, frostfish, tautog, menhaden, and striped bass.  In a few places terrapin are taken, and in Stratford these are much more valuable than the remaining part of the catch.  In 1880, the species reported to be caught in fyke nets were sea bass, cod, bluefish, eels, weakfish, flounders, herring, shad, and occasionally sturgeon.  At Mystic the nets are set about February 1 and taken up about March 31: they are again set about October 1 and remain down until December 31.  Flatfish and frostfish are taken.  At Noank, the nets are fished from the first of February to the last of April, and

from the first of October to the middle of December.  The principal fishing, however, is done in the spring.  The nets are placed in water 6 to 15 feet deep.  In Groton the fykes are operated at the mouths of the rivers during June and July, and within the rivers during the rest of the year; flounders and frostfish are secured.  The nearly 140,000 pounds of flounders, frostfish, and tautog, valued at $2,550, were obtained 1889.  Several nets at Branford were fished for menhaden; about 100,000 fish were taken in the year named.

The fyke net fishery of Connecticut in 1889 resulted in the capture of 455,250 pounds of fish, valued at $8,759, and 1,019 terrapin, worth $1,280.  The quantities of the different fishes were as follows:

Products of the fyke-net fishery of Connecticut.

Appendix #2

Protocol for Hazardous Algal Blooms/Marine Biotoxin Events State of Connecticut
Department of Agriculture Bureau of Aquaculture

Effective Date: 02/23/11


There are three types of shellfish poisonings which are specifically addressed in the NSSP Model Ordinance relevant to the waters of Connecticut: paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP) and amnesic shellfish poisoning (ASP), also known as domoic acid poisoning. All three are dangerous toxins, and PSP and ASP can cause death at sufficiently high concentrations. In addition, ASP can cause lasting neurological damage. PSP is caused by dinoflagellates of the genus Alexandrium (formerly Gonyaulax). NSP is caused by brevetoxins produced by the dinoflagellates of the genus Karenia (formerly Gymnodinium). Both of these dinoflagellates can produce "red tides", i.e. discolorations of seawater caused by blooms of the algae. Toxic blooms of these dinoflagellates can occur unexpectedly or follow predictable patterns. Historically, Alexandrium blooms have occurred between April and October along the Pacific coasts from Alaska to California and in the Northeast from the Canadian Provinces to Long Island Sound; but these patterns may be changing. The blooms generally last only a few weeks and most shellfish (with the exception of clams which retain the toxin for longer periods) clear themselves rapidly of the toxin once the bloom dissipates.

Phytoplankton and shellfish monitoring program:

Mussels are collected from bags located in Palmer and Mumford Cove in Groton and brought to DA/BA laboratory for processing. Additionally, the use of a hydraulic dredge is not permitted in Mumford Cove in order to prevent the re-suspension of cysts of
HAB causing organisms. In Palmer Cove all operations must cease by April 15th before the water temperature rises above 50oF.

Appendix #3



                  February 9, 1984
Mervin F. Roberts
Chairman, Shellfish Commission
Town of Old Lyme
Old Lyme, Connecticut 06371

Dear Mervin:

   There were no detectable MSX infections in the sample of 31 living oysters that you collected from the Connecticut River on November 21, 1983.  With the exception of a few ciliates in the gills of one oyster, no other parasites were noted in the sample.  The ciliates did not appear to be having any effect on the oyster.

   Judging from the samples you have forwarded, it appears that MSX is not a problem for your oyster population—at least not in 1983.  MSX has in the past been found in oysters from New Haven and Milford, Connecticut, and in 1983 we examined infected oysters from Wellfleet Harbor, Massachusetts and Oyster Bay, Long Island.

A sample collected in early December, 1983 from the latter location had a 30% prevalence.  Moreover, 15% of the living oysters in the sample had advanced infections, as did 80% of the dead oysters collected at the same time.  A 15% mortality had been reported in this group of hatchery reared stock since it was planted in Oyster Bay in the summer of 1983, and MSX could certainly have been implicated in the kill.

   Although your community is evidently blessed with a disease-free oyster population at present, it is surrounded by areas in which MSX is established.  The disease could spread into your oyster population since its infective stage is thought to be waterborne.  Certainly it would be in your best interests to avoid importing stock into your area from elsewhere, particularly from locations where MSX is known to be present.

   In view of what is known about the range of MSX, it is rather surprising that no infected oysters have been found in samples from your area.  It would be of value to us to have more information about the range of salinity one might encounter through the year in the vicinity from which your samples have been taken.  You mentioned that such data might be available form Wesleyan University, and if you could obtain it I would be most grateful.

   Please let me know if you have any questions about my findings.  Thank you for sending an interesting sample.

                  Daniel O’Connor
Cc:   H.H. Haskin

Appendix #4


September 30, 1981

Dr. Edward Wong
U.S. Environmental Protection Agency
Surveillance & Analysis Division
60 Westview Street
Lexington, MA  02173

Dear Dr. Wong:

   I have received a copy of the Mumford Cove Shellfish Survey.  I found the section pertaining to the economic value of shellfish populations very interesting. Would it be possible for you to send me a copy of your publication titled:  A Multiplier for Computing The Value of Shellfish?  Eventually I would like to include such a section in future management proposals.

   The management plan for Old Saybrook got off to a rocky start, but is proceeding in the right direction. I have enclosed some newspaper articles for your interest relating to the program.  Hopefully, recreational shellfishing will occur shortly.

   Thank you for your assistance in May and for including me in the Mumford Cove study.

                     Sincerely yours,

                     Timothy Visel

Re-keyed for The Sound School by Susan Weber

Appendix #5

Mumford Cove Shellfish Survey
Groton, Connecticut
June 1981-A

U.S. Environmental Protection Agency
Region I
Surveillance & Analysis Division
60 Westview Street
Lexington, MA 02173


The U.S. Environmental Protection Agency appreciates the interest and efforts of the people who volunteered and assisted in the completion of the Shellfish Survey of Mumford Cove, Groton, Connecticut.  We extend our thanks and acknowledgement to the following people:

   Edward F.M. Wong      Project Director

   Richard T. Sisson      Principle Marine Biologist
   Arthur Ganz         Senior Marine Biologist
Barbara Simon         Computer Programmer

      Paul Baczenski         Group Leader

      Malcolm C. Shute Jr.      Principle Sanitarian
      Donald Bell         Senior Sanitarian
      James Citak         Senior Sanitarian

      Edward Parker         Principle Sanitary Engineer
      William Hogan         Principle Sanitary Engineer
      James Grier         Principle Sanitary Engineer
      Michael Powers      Sanitary Engineer
      Gary Powers         Sanitary Engineer

      Dr. Thomas Hatfield      Chairman, Life Science Department
      Virginia Magee      Instructor of Biology
      Donna Magee         Student
      Timothy C. Visel      Instructor of Marine Science

The Study

   Presently, and dating back for many years, Mumford Cove is closed to shellfish harvesting.  However, recreational sports such as fishing, boating and bathing on a private beach are available to residents of the immediate area.  The shellfish closure is due, in part, to a sewer outfall that empties into a stream at the Cove’s headwaters and also, discharges from a sanitary landfill located north of Mumford Cove may be involved.

   The U.S. Environmental Protection Agency, State, local officials, and area residents of Mumford Cove know that unless the pollution standards are met, there will be no chance of lifting the shellfish closure imposed on Mumford Cove by the State Department of Health Services.  There are proposals to remove the sewer outfall and have it placed in an area remote from Mumford Cove.

   Therefore, EPA with the help of several organizations, performed a shellfish survey in Mumford Cove to determine the densities, type and sizes of the shellfish in the beds.  Furthermore, the value of the shellfish will be estimated and compared with shellfish at the market level.

Cove Profile

   The Cove bottom is mostly sand and gravel with a slight tendency toward siltation in certain areas.  The bottom of Area 1 consists mostly of sand and gravel.  The channel bottom, however, is mostly mud and becomes anoxic toward the headwaters.  We noted that the reaches of the headwaters had the appearance of septic conditions at the time of the examination.  Intertidal zones of Area 2 are mostly gravel, sand and silty-sand.  The northeastern portion of this area shows a heavy growth of a green sea lettuce.  Most of the shallow portions, averaging about two to four feet in depth, indicate a predominance of mud and some silty sand.  The outer portion of the Cove, adjacent to the closure line, is mostly gravel, sand and cobblestone.  The bottom is fairly firm at this point.

Re-keyed for The Sound School by Angela Lomanto

Appendix #6

Waterfowl Prefers Ruppia – Food of Game Ducks in the United States
Martin et al., 1939


By A. C. Martin and F. M. Uhler
Associate Biologists
Section of Food Habits
Division of Wildlife Research
Bureau of Biological Survey

Technical Bulletin No. 634 – March 1939
US Department of Agriculture
Washington, DC

Ruppia maritima: Wigeongrass (pl. 27; fig. 29).

   Value. – Excellent.
   Parts consumed. – The seeds (drupes) and vegetative portions.
   Identification. – Though wigeongrass and sago pondweed have some resemblance to each other in their vegetative parts (refer to treatment, p. 26, of Potamogeton pectinatus for comparison), their seeds (pl. 27, B) are very different.  In widgeongrass the seeds are small, blackish, and pointed and are borne in slender-stalked clusters (umbels).
   Environment. – Widgeongrass is a characteristic plant of brackish coastal waters and of alkaline lakes in the West.  In the Potomoc River it is found all the way up from the strongly brackish water of Chesapeake Bay to a point where the average salt content is equivalent to only about 2 to 3 percent or normal sea salinity.  Bourn (7) found experimentally that this plant thrives in water having salt concentrations ranging from 0 to 80 percent of normal sea salinity and appeared healthy after 3 months in concentrations up to 150 percent of sea salinity, although it did not make active growth or produce seeds in the higher salt concentrations.  Ruppia grows on either fertile or sandy bottoms at depths ranging from a few inches to several feet.
   Propagation. – By portions of rootstocks or by seeds.
   Related species. – Ruppia occidentalis (pl. 28) is a large form of wigeongrass that occurs locally in alkaline or saline lakes of the West.

Re-keyed for The Sound School by Angela Lomanto

Appendix #7

The Day
Thursday, January 15, 1987
After Outfall: Cove Residents Seek Comeback
   By: William Hanrahan, Day Staff Writer   

GROTON - Now what for Mumford Cove?
   Given new life by a federal judge’s order to stop dumping treated sewage there, the polluted cove still faces a period of recovery.
   As has been well documented, sometime within the next two years the town will stop dumping millions of gallons of treated wastewater into the cove, and redirect the waste to the Thames River through a sewer outfall pipe.
   But a little-known part of the final court settlement requires a three-member committee to study the restoration of the polluted cove.
   “It will be quite interesting to see if it recovers on its own,” said Paulann H. Sheets, spokeswoman for the Mumford Cove Association.  “I think there’s going to be a very substantial improvement.  That’s my own uninformed opinion.  I have a great deal of confidence in nature to recover from human-inflicted insults once we remove them.”
   Although the committee has not met, its members have been identified as Ronald C. Kollmeyer, an oceanographer who will represent the town; Malcolm Spaulding, a University of Rhode Island professor representing the cove group; and Fred Banuck, principal sanitary engineer from the state Department of Environmental Protection.
   “They will be responsible for deciding what the impacts will be of turning off the sewage,” Mrs. Sheets said.  “It may well be that it will take too long for the cove to recover by itself, in which case it might be appropriate to look at some strategic dredging in the channel.”

Appendix #8

Duckweed A Nuisance DEP Report
Control of Water Weeds and Algae
Connecticut Department of Environmental Protection


When present in moderation, algae and aquatic weeds are beneficial to a lake or pond.  However, when these plants become overabundant, they will lower the recreational and aesthetic qualities in a body of water.  The most effective and economical method of controlling nuisance growths of algae and water weeds is by the application of chemical herbicides or algicides.  It is hoped that this brochure will assist the pond owner or lake property association in becoming acquainted with the problems associated with, and the materials used, in the control of aquatic vegetation.

Filamentous Algae

Filamentous algae includes many different species of plants that consist of long hair-like strands.  They may be either slimey or cottony in appearance.  This algae begins its growth on the pond bottom, but may float to the surface due to entrapped oxygen bubbles produced during photosynthesis.  Floating filamentous algae can best be treated by spraying the algicide directly on the “algae mats.”
Duckweed (Lemna spp.)
Watermeal (Wolffia spp.)

Duckweed and Watermeal are the smallest of the flowering plants.  Duckweed has tiny leaves with rootlets hanging down in the water and appears in tiny clovers floating on the water surface.  Watermeal has neither leaves nor rootlets and appears as minute green grains floating on the water.  Both plants tend to occur together.  Frequently the growth of Duckweed  and especially Watermeal can be so abundant as to form a green cover one to two inches thick on the water surface.  These plants are quite difficult to control and are best treated on calm days when they are not concentrated into one section of the pond by wind.

Appendix #9

The Day, New London, Conn., Wednesday, June 12, 1985

Specialist warns agency of ‘black mayonnaise’ threat

By William Hanrahan
Day Staff Writer

GROTON – they call it black mayonnaise – it’s the murk and muck, sometimes several feet deep, that collects on river bottoms.  It’s also the stuff stifling the area’s oyster crops, according to an expert.

Addressing the town’s Shellfish Commission Tuesday night, Timothy c. Visel, a marine resource specialist for the University of Connecticut, said the build-up of debris in shellfish areas can weaken or eliminate growth.

Working in waters off Old Saybrook, Clinton and Madison, Visel said production of oysters there has more than quadrupled thanks to clean-up efforts during the past three years.

“There seems to be a trend that our rivers are filling up with black mayonnaise,” he said. “We have seen a dramatic increase in river life as the dead stuff is removed.”

The accumulation of debris occurs in waters with poor circulation. “We get so many nutrients going into these sluggish coves without a lot of circulation,” Visel said. “This causes a build-up and no oxygen gets down in the water.”

Visel said removing debris not only enhances oyster growth, but has increased the presence of a number of other fish, including flounder.

Visel said Connecticut used to be a leader in oystering about 100 years ago, with local areas such as the Poquonnock River as prominent beds. More than 100 oyster companies on Cape Cod used to rely on seed oysters from Connecticut which were brought there to mature.

Production dwindled to almost nothing as waters became polluted, he said.  A clean water act in the late 1960’s helped rekindle the industry during the 1970’s, but things are still not what they used to be.

Removing black mayonnaise helps oysters and other life forms grow and even cultivate in areas previously devoid of life.

“About 1500 bushels came out of Old Saybrook last year and no shells were put in the water,” he said.

Visel said areas, where mud is a problem, often smell bad or show a white, milky substance floating on the water.  Commission members said they had seen signs of this in town waters.

Debris can be removed from river and cove bottoms with oyster dredges, Visel said.  By stirring up the mud at high tide, the debris is able to flow out of the area when the tide changes.

Debris can consist of decaying leaves, sticks, logs, garbage and nutrients, which build up in the water.  Visel said water jets also have been effective in removing mud

The commission plans to study the information presented by Visel before considering possible action.

Appendix #10

Tampa Bay, Indian River and Lake Studies Lead
Nation about Sapropel-Nitrogen-Ammonia
Sapropel/Submerged Aquatic Vegetation Contain Bacterial Processes Related to Climate Cycles

In the 1950’s and 1960’s, effects of a changed water cycle in the Everglades had caused researchers to concentrate on Florida peat studies – an area that is often “hot” according to our New England standards New England was in a cold climate cycle with subzero temperatures that freeze bays and salt ponds. Here in the fisheries literature you see the results, of this New England cold strong hurricanes, thick ice and shorter growing seasons.  Seed companies faced with a shorter growing season developed the “number of days till harvest” seeking on advantage for marketing.  Seed packets sold today same reference the growing season time.

But in the 1950’s and 1960’s if you were interested in the sulfur cycle or sapropel, you needed to be in Florida.  Most of the direct references to sapropel or subtidal peat – either in the formation of coal or using such wet peat for agriculture Florida was the place to be.  In fact, Florida hosted the first agricultural Peat Experiment Station in Belle Glade opening in 1923.

To fully understand sapropel you needed to look at bacteria and the formation of coal.  It is the sulfur reducing bacteria (SRB) that utilize sulfate as an oxygen source and in the process seeped hydrogen sulfide into this ooze and later fossilized is coal seams.  That is how sulfur was introduced into coal by bacteria.  To have this happen it needs to be “hot” and oxygen bacteria not present or at least then a small part of the bacterial population.  This is why coal was formed long ago when the earth was hot and sulfur was a dominant atmosphere constituent.  In fact the discussion about global warming is largely the possible return of sulfur to the loss of oxygen requiring life.  Putting sulfides into the air hurts oxygen life – it is as simple or complicated as that.

That is one of the interesting aspects of the blue crab, it is so to speak as it can carry vibrio bacteria, with little effect (it seems), while vibrio bacteria is a pathogen to many organisms (including us) the blue crab lives in an environment that fosters sulfur bacteria but has adapted to its presence.  Some research has indicated that some species have the ability to immobilize vibrio – not kill it but to make it “sticky” by changing bonding locations as to make them ineffective.  It was described to me as grease on a door knob- the door is still there but the knob has no grip and therefore cannot “be opened.”  To understand the chemistry of sapropel the explanation of this bacterial battle needs to be included.  The area of study that allows us to study this bacterial battle is the soils and peats in cold or hot periods, and Florida presents a longer grow, season for sulfur because its climate is warmer (New England has vibrio perhaps in only the hottest of times).  In cold and in oxygen containing waters sulfate reducing bacteria loose to oxygen bacteria that are energy efficient.  In heat, sulfate-reducing bacteria (SRO) set the habitat conditions that extend into acid conditions and sulfuric acid soils that can be part of seafood disease and parasites.  Sapropel is now considered a bank of spores and cysts that are possibly released in rapid sulfuric acids (part of the sapropel – sulfur cycle) that activate disease hosts even perhaps the dreaded oyster disease MSX.  There appears to be a correlation between storms and disease perhaps related to release of sapropel spores and cysts – the creation of acid bottoms that could activate these spores and cysts.



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