EC #31 - Part 2: The Battle for Salt Marshes and Blue Carbon

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EC #31 - Part 2: The Battle for Salt Marshes and Blue Carbon
Salt Hay, Duck Ponds and Wharfs – All Part of The Nitrogen Cycle
Sulfate Supports Salt Marsh Composting in High Heat
Viewpoint of Tim Visel – no other agency or organization
This is a delayed report March 2020
Tim Visel retired from The Sound School June 30, 2022
The Nitrogen/Bacteria habitat series has had over 150,000 views to date
Thank you, The Blue Crab Forum^TM for supporting these Bacterial Nitrogen Reports
 
 
 
A Note from Tim Visel
 
When I wrote EC #7: Salt Marsh and Dangerous Bacteria in Warming Waters (September 10, 2015), I was watching conservation efforts turn to the concept of "banking" organic carbon.  The first terminology often had the term "offset" as a mitigation of human released carbon or human "footprint."  The phrase "reducing your carbon footprint" has indeed become a popular conservation phrase in the last decade.
 
Most of the time, the carbon credit policy has been an effort to raise funds for further environmental/conservation efforts.  This practice evolved initially from mitigation of resource loss – tree planting in forestry and dune beach grass planting erosion control are two well-known mitigation policies.  Setting aside wetlands or bogs for land trusts came from the practice of purchasing specific rights, such as mineral, sand or timber "rights" apart from just land ownership.  I came across deed written "sand rights" while employed on Cape Cod and "seaweed rights" were often found as clauses in early Connecticut deeds.  So, the concept of natural use processes (such as water rights) have long been recognized as having commercial value – to be bought and sold in land transactions.  This was the foundation of carbon rights, which led to commercial value.  Today, carbon "credits" are bought and sold openly on commercial markets.  They often have no connection to restoration other than a cost imposed upon pollution (or polluters), as in this case, the release of carbon and its connection to climate warming.  It is sometimes referred to as a "shame tax" or indulgence to pollute.  If you were seen to be a large generator of carbon, the more "offsets" or carbon credit purchases were frequently needed.
 
I watched as the carbon credit concept developed from banking forestry products or manure to "bio gas" alcohols and now credits for natural bogs, marshes and saltwater organics termed "blue carbon."  Here, the value is assigned to non-use instead of the previous rights for resource use.  It was interesting to see this process evolve – to the value of something if you don't use it.  (Imagine if you were paid not to use electricity based on your highest monthly bill.)  This was soon augmented by the evaluation of the capitalization of natural carbon banking by nature in the organic deposits created by bacteria.  That is what blue carbon is – the remains of plant tissue digested by bacteria, resulting in underwater marine compost piles, similar to land-based well-rotted manure.  I was exposed to this concept when a Washington state firm valued the muds at the bottom of Long Island Sound at hundreds of billions of dollars (See The Trillion Dollar Asset Prepared by Earth, Tacoma, Washington 2015.  Prepared for The EPA Long Island Sound Study and New Engine Interstate Water Pollution Control Commission, 84 pages).
 
The mention of salt marshes and eelgrass peat as living "carbon sinks" are places where carbon is naturally "banked" and viewed as important to fighting global warming.  Other than explanations of how this organic deposit is held by plants (mangroves in tropical climates) little else is provided – my view to the bacterial processes of this carbon concentration.  (This is the bacterial climate battlefield that I mentioned in EC #7, posted September 10, 2015, The Blue Crab Forum^TM.)
 
A key factor in this process is often the presence or lack of oxygen, which involves the sulfur, iron, carbon and nitrogen cycles.  This organic deposit over time becomes the largest carbon bank of nature – fossilized sapropel or "coal."  Dead plant tissue containing carbon from the atmosphere (CO₂) is part of the photosynthesis process of plant life itself.  Plants use the carbon of atmosphere CO₂ (which is .04 % of the atmosphere today) and nitrogen, which forms 78% of the atmosphere to form the basic building block, cellulose, a structural sugar which binds carbon in living plant tissue.  When the plant dies or sheds bark or leaves, it loses the carbon component fragment as well.
 
This organic deposit is bulky; it takes up space but bacteria soon begin to digest plant tissue we call composting.  Many homeowners experience this as the huge fall pile of leaves only to see in spring a much smaller pile.  Very rarely have I heard this process described as an "enriched bacterial residue of carbon fractions" but that is what it is – a type of bacterial manure that, with sufficient oxygen, was "reduced" to a much smaller deposit, usually black with much less structure (i.e., woody tissue).  Recycling organics for home gardens is a huge industry and important to replenishing lost carbon harvested as vegetables or flowers.  It is frequently termed as "mulch."  When gardeners purchase mulch, it is a type of carbon reserve to the soil.  Restoring carbon to agricultural soils is an area of increased study and research.  Lawn care is one type of carbon replenishment as it promotes a grass monoculture.  A newer concept is the mulching of cut grass in place so as to keep carbon recycling on the lawn (grass) itself.
 
The Blue Carbon effort is built on a similar natural process except it is not to be used.  It is to be held in storage or "banked."  Some of the first carbon offsets were based on cow manure in Europe, except that in some cases, the banked manure was then used on fields, thereby negating the set-aside or offset concept.  Other carbon credit programs did not include Europe's VAT (Value Added Tax) for creating wealth and ended up in courts (See Trial of Carbon Tax Fraud of the Century Opens in Paris, September 13, 2017).  But most Americans have already seen "banked carbon" and did not realize the bacterial action that released "compost gas" we call "natural" gas – methane or a carbon atom surrounded by four hydrogen atoms or written as CH₄.  The visual example is easily found in closed landfills when I was growing up termed "dumps."  It is here that the remains of uneaten food, paper or at first tree limbs and leaves were buried in the ground.  These closed landfills were often capped with a thick layer of dirt blocking oxygen exchange.  About two or three decades later, some closed landfills started to catch on fire, even below the dirt cap.  It was explained that just burying organic carbon locked in plant and vegetable tissue could support a family of bacteria that don't need oxygen to compost this carbon and produce heat and methane gas as a result of anaerobic bacterial metabolism.  This has been known for decades that organic carbon in the form of cellulose can emit huge amounts of methane.  This bacterial action produces heat (any terrestrial composter may see "steam" coming from a compost pile even while snowing as I have seen) and can cause buried landfills to burn underground.  Once they ignite, they are extremely hard to extinguish and can last for months, even years.  Landfills today are sometimes covered in white pipes (vents) to release the methane gas before it can explode.  A few states have enacted gas capture technology in the hopes of using methane as a commercial product – others just "flare off" the waste methane before it can build up to create a fire.  In this case, the bacterial response to carbon is to produce a much more damaging climate gas methane. 
 
Much of the blue carbon initiative has focused upon the carbon sequestering aspect without mentioning the bacterial role in releasing ammonia, hydrogen sulfide and methane.  This is a concern as it tends to modify or ignore problems with blue carbon.  A report in Connecticut contracted by the EPA Long Island Study in 2015, The Trillion Dollar Asset: Monetizing Ecosystem Goods and Services (pg. 33), detailed the value of Long Island Sound's wetlands, seagrass, watersheds and marine muds estimated up to $136 billion of sequestered carbon.  Carbon credits (carbon indulgences) are often purchased by commercial enterprises to gain goodwill with environmental organizations.  They rarely reduce carbon pollution but impose a type of tax upon commercial interests.  Often, these costs are transferred to consumers and recently described as "public benefit direct cost."  The carbon banking process is a growing conservation and environmental issue – my view, Tim Visel.
 
In our region, more and more emphasis is being placed on the value of salt marshes and eelgrass monocultures to gather organics and compost them, forming a type of carbon bank, which is a natural process.  Our temperature, climate and glaciation has not allowed mangroves to form along our coast and like the great plains energy profile (fires) has held succession to that of grasses.  By sealing organic matter from oxygen and oxygen-requiring bacteria, nature guarantees a ready supply of food for the methanogens and a constant non-manmade source of methane natural gas.  This process occurs in salt marshes and eelgrass peat but is frequently not included in blue carbon discussions.
 
Instead of focusing attention on organic matter bacterial decay that produces methane gas, the health of salt marshes was placed almost entirely upon human coastal development activities.  This continues today with the bacterial action of marine organic matter composting almost largely ignored by climate change studies.  Nowhere is this more apparent than in recent studies of blue carbon – a policy of human disturbance largely replaced the bacterial change in deep accumulations of organic matter in deep marine sediments (See Appendix #1 and Appendix #2).  We may find that keeping organic carbon residues exposed to oxygen may increase CO² but reduce the more dangerous climate gas emissions of methane. (Methane gas is estimated to be 28 times worse for climate warming than carbon dioxide (CO₂)).
 
After World War II, development activities along the coast did increase.  Local motorboat clubs formed and recreational fishing surged.  The commercial fishers along Connecticut's coast watched as dredge cuts increased, marshes were filled or dug out for marinas.  I can recall Nate Walston's response in terms of a Guilford East River dredging project that post-1945 it seemed to him "The Army Corps had declared war on us." 
 
The coast in the next two decades became a busy place as marinas increased to fulfill a surge in recreational boating – boat ramps were built and shorelines bulkheaded 1946 to 1966.  These same activities took place along the shore and in the least developed places, the salt marshes.  That is how the concept of environmental protection started a realization that marshes were important to many species and contained habitats important to both recreational and commercial fisheries.  The small boat fishers of the coast already knew that, they fished in them.  That battle soon was waged in the most visible habitat type, the salt marsh.  This would put coastal dredging into the national environmental spot light.  However, salt marshes have been studied for centuries.
 
Long forgotten the source of very valuable salt hay harvests (current perceptions are that one or two cuttings per year actually strengthened the Spartina patens monocultures and helped keeping phragmites out of them) its large salt hay operations along Connecticut's had largely ceased by the 1950's.
 
Most of the marshes in western Connecticut had already been filled following the Greenwich Malaria outbreak 1898 to 1910 but the scourge of mosquito disease caused the state of Connecticut to declare marshes a public health hazard in 1895, which they were then drained or filled.  But some dredging had frequently occurred in marshes to keep channels clear, to remove trees uprooted in spring floods or to keep ports in operation.  The marshes were of value and important to fisheries, but this was also the time of great storms and floods and national legislation to save beaches, helped by then Senator Prescott Bush of Greenwich, as Connecticut suffered horrific floods in the 1950s.  This federal effort is evidenced by some of the first Flood and Erosion Control Boards in local towns – a mandate to control floods and slow coastal storm erosion.  Environmental protection legislation to protect the coast included those who sought to protect the coast from storms.  This conflict continues today with recent living shoreline legislation fact sheets and programs.  This was a massive shift from protecting the coast (Nature) to shoreline retreat – or letting sea level rise "win."
 
Losing sand from beaches was, at times, both an economic and emotional loss.  The negative NAO pattern had replaced the largely quiet 1880-1920 "heat" now it was active and had beach erosion at a rapid pace.  The 1955 Connecticut hurricane season had Connie and Diane come only 8 days apart. 
 
Bulkheading shorelines, diverting streams and flood dikes were built in response to the devastating floods in the Naugatuck River Valley (1955).  If the remaining salt marshes were to be saved, the battleground was not in the marsh itself but with those that ultimately controlled the fate of them, elected officials and, in turn, the public that, in turn, elected them.  The battle for salt marshes would be fought with the most powerful tools, the pen (education), the science and grant funds to support them both.  It was a massive shift in viewpoints and perceptions which then involved the legislature of not just Connecticut but along many shorelines.  A conflict soon happened between those living on the coast and those who wished to protect it.
 
That had already happened in Connecticut a century before our Environmental Protection Act in 1972 but in 1872 by Connecticut farmers.  Tired of fraud in the fertilizer market, they turned to the Connecticut General Assembly for help to build the first Agriculture Experiment Station in the country, here in New Haven.  Farmers, at the time, were confronted by a massive bias of perspective, the firms that sold the fertilizer paid for (science) testimonials and analysis that would, 100% of the time, support their products. (Today, this is recognized in the scientific community as the "funding effect.") The farm community soon got "honest science" for accurate fertilizer analysis, not unlike the paid promotions of supposed cures and remedies.  The abuse of science studies and misconduct of medicine was to eventually create the Food and Drug Administration with magic potions and medicinal powders still recalled by its most infamous example – snake oil.  We have something similar, unfortunately, with some nitrogen studies – my view, Tim Visel.
 
Salt Marsh Chemistry and the Nitrogen Cycle
 
The chemistry of salt marsh habitats has been controversial for many years, even the creation of two salt marsh nitrogen bacterial pathways – the high marsh and the low marsh.  The concepts of organic matter "outwelling" – source material or which organic pathway should be highlighted as a positive outcome, would divide the research and ecology fields for decades.  These pathways were often described as "energy flows" from John Teal's early work, which was done in a salt marsh at Sapelo Island, Georgia; it was estimated that tides removed 45% of organic matter production, salt hay, before marsh consumers could to use it.  But this study and others that followed looked to organisms other than bacteria (it was much more exciting perhaps to report if salt marshes fed fish rather than bacteria), which did use this organic matter, detritus, and did not, in many cases, include terrestrial organic sources i.e., organic matter that was not produced in the marsh itself but in fact was swept into it.  That would not take into account salt marsh processes of organic trapping – trees, logs, limbs, woody paste and of course leaves that so plagued the turn of the century oyster culturists.  This opens the question if not the production of a marsh itself is dependent upon climate (temperature) and energy events and not just coastal public policy issues (it was thought that some researchers had maximized the value of salt marshes as to assist preservation interests).  At the time - John Teal brings this issue forward in his June (salt marsh studies) 1986 report titled The Ecology of Regularly Flooded Salt Marshes of New England – A Community Profile and his comments on the danger of science, quoting the concept of trading "Credibility for Political Advantage".
 
But I contend much of the organic transport from the marsh did not come from it at all rather as a composting mechanism – organics from land and sea with multi-faceted bacterial roles of composting bacteria, in the marsh peat itself.  The release of nitrogen frequently from these pathways were glossed over for more public acceptable benefits as fish and shellfish and not primary and secondary sewage compost bacterial pathways.  Although researchers did note that at times nitrate was a product of salt marshes, others at times noted that nitrate was consumed from marsh surfaces or contact waters for both processes directly attributed to bacterial reduction oxidation (compost processes) – and often were not mentioned.  Nitrogen was certainly not a public policy agenda action item in the 1970s.  Descriptions of bacteria use or terrestrial inputs were often put in complex terms and at times perplexing language if included at all.  This was to change as waters warmed and nitrate lessened as ammonia increased.  The heat would change bacterial composting species those that could metabolize sulfate as a source of oxygen.  Sulfate dissolved in seawater will never run out – it is termed "non-limiting."
 
Salt marshes, like most peat bogs, are accumulations of organic terrestrial and marine residues of organic matter.  As such, bacterial respiration in these water-soaked soils is temperature dependent and related to oxygen saturation in pore soil spaces.  In times of heat, bacterial reduction is slower and ammonia generation higher – and when colder nitrate may be produced.  The bacterial reduction process is governed by climate (temperature) and the amount of forest trees or any organic inputs adjacent to the marsh.
 
As the outwelling controversy continued (it is still ongoing), whether salt marshes exported organic matter into coastal waters or that the marsh itself stored and utilized it – terms for close or nearby such as the forest came to describe leaf falls or organic sources into them.  These organics could be linked to bacterial residues from sulfate reduction in the Narrow River, Rhode Island in the 1970s (See Anoxic Water In The Pettaquamscutt River, Gaines et al., January 1972). 
 
Most marshes receive freshwater discharges that contain organics, that is how West Coast researchers tried to describe a failure to describe such nitrogen inputs into nitrogen TMDL limits (See USGS "Quantifying Nitrogen Fluxes In Puget Sound" March 13, 2014, Richard H. Sheibley – Anthony J. Paulson).
 
Many times, salt marsh peat (base) develops as a result of terrestrial organic matter.  Bacterial release of carbon and nitrogen often fuels algal blooms, especially in warm waters.
 
There continues to be a huge absence of impact of natural vegetation (leaf fall) impacts to salt marshes – leaf falls that are natural and those perhaps enhanced by storm water.  Here, organic matter enters creek and river systems and passes to estuaries where it can settle.  Water-dissolved nitrogen, in fact, may never reach the marsh surface as it often accompanies large rainfall events and it is cast directly into the sea.  As freshwater is naturally acidic, even urea (a nitrogen found in human/animal urea) is mobilized quickly in acidic waters – as on land soils that are acidic in high heat "lose" ammonia to the air.  Ammonia a toxic substance to sea life and one of minimal value to many terrestrial plants.  This difference is observable between grasses that utilize nitrate (including eelgrass) and ammonia nourishes non-rooted plants or macroalgae such as Ulva species we call sea lettuce.  The difference between nitrate in cold and ammonia in heat is climate related and dependent upon a oxygen "redox layer."  This bacterial digestion of organic matter is often described as a depth in salt marsh peat in which oxygen is limiting or an anaerobic layer.  To reduce the organic matter in a chemical reaction, bacteria use oxygen and its electrons to release energy.  One may consider that bacteria "eat" the organic matter but need oxygen from the air or dissolved in seawater to do it.  The layer refers to a point in which oxygen in its elemental form becomes scarce or "limiting."  At this time or layer, other bacterial utilize compounds that contain oxygen but are not as efficient as those that utilize elemental oxygen.  It is here in the tidal peat and mudflats that sulfate dissolved in seawater is metabolized by sulfate-reducing bacteria commonly referred to as "SRB."  Other bacteria may utilize nitrate and other nitrogen compounds for energy and gives rise to nitrogen ions needed by plant life.
 
The dilemma comes in as measuring organic nitrogen released by bacteria versus human nitrogen dissolved in water?  Further complicating also arises over climate - a warming climate would naturally reduce oxygen, creating a greater ammonia pathway while cold reduces organic inputs (shorter number of growing days) which now favors nitrate.  Human nitrogen (and agricultural) inputs that enter in the coastal environment in water – able to flow (a type of outwelling) is frequently governed by tidal flushing.  Human and agricultural nitrogen moving into water courses with poor flushing (tidal restrictions) would have greater impacts upon plant life that is quickly able to mobilize it (use) than deep rooted plants.  It is in these shallow heat sensitive habitats that see massive macroalgae "blooms" often proceeded by plankton blooms or HABs (Harmful Algal Blooms).   
 
Here, waters can turn brown, red or even purple as algae blooms respond to available nitrogen compounds – the most responsive being ammonia.  Plants that can switch, utilize from nitrate to ammonia, will dominate in heat.  Those that need nitrate only will diminish or "die off" when these compounds become scarce or "limiting."  In fact, if you consider the natural filtering abilities of sapropel, nitrite and nitrate are both "oxygen" sources for bacteria and important to bacteria life forms (See EC#10: Did We Remove the Correct Nitrogen Compounds in High Heat, posted December 17, 2015, The Blue Crab Forum^TM Environment Conservation thread).
 
In time, we may find the organic matter nitrogen (leaves, woody tissue, bark, grass clippings) is far more damaging than aqueous nitrogen as it is food for bacteria and heavy or prolonged rains deliver this food into those habitats most susceptible to climate change, the shallow habitats which form the nursery areas for fish and shellfish.  Ocean sources of organic matter algal blooms and plankton are "soft walled" cells and easily broken down by bacteria.  The plant tissue of leaves or bark takes much longer to digest.  Its sugar lies in the tough woody compound of cellulose.
 
In terms of coastal ecology, salt marshes can, at times, export organic matter with at times storing it (sea level rise) they also have a dual organic pathway of export from land, passing through them.  Most reports do not mention this export but a large focus upon human nitrogen enhancement on marshes.  We tend to focus upon the impact of nitrogen entering the marsh but little on the impact of its leaving and in what form.  In heat, the bacteria that oxidizes ammonia into less toxic forms (nitrite and nitrate) die off, leaving ammonia levels to increase.  Removing nitrate, while a nitrogen nutrient for plants, can be considered a potential source of oxygen for bacteria. Nitrate, in fact, may help eelgrass root rhizome fields from becoming sulfide-rich.  Iron mineral soils react with hydrogen sulfide and produce monosulfide – the color of black iron.
 
Although some researchers have found negative relationships between coastal salt marshes and coastal development, a better correlation perhaps is the association that bacterial nitrogen and salt marshes are shoreline nitrogen pollution features.  They are subject to faster heating and cooling and, therefore, different bacterial pathways during hot and cold cycles.  This appears to be true with nitrogen studies as well.  Most aqueous nitrogen is delivered to the marsh creeks in the chemically high reactive zone – rich with bacteria that can utilize several forms of compound oxygen – nitrite, nitrate and sulfate.  That is why in heat, nitrate may become limiting or scarce, and in cold, marshes may shed nitrate; it's not needed and the colder oxygen/nitrate pathway now dominates.  This also drives the spring blooms of algae that need nitrate and why the toxic blooms (browns) occur in late August when the high heat ammonia pathway is much stronger (See EC#8: A Long Hot Spell May Reverse These Bacterial Filters, posted October 30, 2015, The Blue Crab Forum^TM Environmental Conservation thread), changing them from nitrate to ammonium.
 
Salt marsh studies that do not reflect temperature changes and do not take into account bacterial reduction nitrogen pathways or terrestrial organic matter nitrogen inputs are biased by omitting this perspective (my view, T. Visel). In high heat, marshes can become enriched in sulfur compounds and other toxic sulfur substances, killing salt marsh plants and many forms of sea life (See EC#7: Salt Marshes - A Climate Change Bacterial Battlefield, posted September 10, 2015, The Blue Crab Forum^TM Environmental Conservation thread).  Salt marsh research efforts should include bacterial reduction pathways and climate impacts that appear to be cyclical.  That is why crabbers and shellfishers are often the first ones to report nature's compost pile impact as they are the first ones to see it.  Hurricanes are especially damaging, not so much for the energy (which in the marine zone rinses soils) but the associated rainfall and floods that carry huge organic inputs as the leaves and wood tissue washed into estuaries.  Sometimes, the leaves deposited can be measured in feet (personal observations, the Hammonasset River oyster beds (1987-1988) following Hurricane Gloria).
 
In areas that contain blue crabs without marshes to hold terrestrial organic matter, they can be overwhelmed by flood waters carrying huge amounts of decayed leaves and bits of organic matter, turning the water brown.  That is what makes blue crab habitats so unique.  They exist right at the edge of this organic chemistry battlefield – too much heat, a jubilee; too much cold, sulfide/acid kills.  That chemistry could explain how greatly blue crab catches fluctuate year to year and the need of including habitat chemistry in future blue crab studies – my view, Tim Visel.
 
Salt Marshes – Marine Peat Bogs

 

Salt marsh researchers in the 1950's and 1960's in New England generally dismissed forest/leaf impacts in the coastal zone.  It was cold then (colder), oxygen was available, organic material was quickly broken down – composted.  Salt marshes became a somewhat isolated habitat, productive in its own right but subject to climate and energy as well.  This led to a controversy among salt marsh researchers as to the "outwelling" of nutrients from salt marshes, which were peat deposits in the marine environment.  Peat soils once stabilized can be important agricultural soils – and sulfur/nitrogen bacterial pathways were well known in the 1920's.
 
Much of the early work on the value and productivity of peat soils was done at the Gladview Peat Agricultural Experiment Station in the Florida Everglades (established 1924 operations began in 1928).  Peat soils composed of roots from surface plants once stabilized for pH can be very productive acid soils.  The pH and color were controlled by the amount of iron.  Iron was an important part of peat soil biochemistry, which included bacteria.  Once exposed to oxygen, any iron would form iron sulfides – black, while peat below oxygen layer or dry would remain brown.  The bacteria in oxygen limited regions used sulfur compounds for reduction while surface bacteria had access to oxygen where a faster reduction (composting process) occurred.  This is the pathway most gardeners experience as mulch or soil conditions over time disappear as much as a fall leaf fall.  In the presence of oxygen sulfides rarely form.  Sphagnum peat moss is a very important commercial product today sold mostly as a soil conditioner and humic acid needed to stabilize pH.
 
Although not high in plant nutrients itself, it is the food for bacteria that make these plant nutrients available.  When you feed your soil, you actually culture living bacteria.  The concept of agriculture "living" soils as they themselves are alive and helping "feed" the plants and why high-heat forest fires are so damaging.  High-heat fires can kill the bacteria deep in forest soils, which slows habitat succession (restoration) by reducing bacteria that "fix" nitrogen from the air.  Forest soils restoration was a huge issue in the "dry" 1920's and 1930's before and after the dust bowl.  Water flowing across peat can pick up characteristic peat residues in the water. They are often brown from tannins and can be black – the term blackwater can be found for rivers that obtain enormous amounts of tannins (including those rivers that obtained wood pulp and sawdust).
 
The salt marsh preservation effort in the 1950's and 1960's was to guide the value of salt marshes as unique highly productive habitats critical to many organisms.  It was not so much the peat (with reactive oxygen, a source of CO₂ to the atmosphere) or organic salt hay (the structure of which was difficult to reduce, making it a great mulch) production but the subtidal habitats within the marsh for fish and shellfish.  The "salt marsh" was to include the subtidal areas as well as the creeks, canals, ditches and pools important to species of value, such as fish and shellfish and a critical food web for waterfowl. 
 
Most of the northern salt marshes were habitat stopovers for migratory birds, visitors but not always residents.  The real value was the creeks and coves, the subtidal flats, these were home to bank crabs, oysters, clams – these did not migrate and here were some of the most important habitat histories.  The marine food web, as presented in the 1950's and 1960's, had the salt marsh producing organic matter for food – nature's supermarket for numerous species that consumes it including the bacteria that needed oxygen.  The critical aspect of this food web would be that Spartina grass was the largest supplier of organic matter to the marine environment – not land.  It is ironic that this should occur (completely understandable at the time for "marketing" the importance of salt marshes to the public) as the peat in the marsh is largely terrestrial land source material, leaving a tannin signature and well documented in terrestrial peat studies of pollen.  But the concept of Spartina species providing all the organic matter certainly raised the level of salt marsh importance and, therefore, the need to save them.  What was surprising is that the science community largely supported this effort – and "nearby" terrestrial organic inputs minimized.  In time, salt marshes became "priceless."  There were problems one of which that peat collects/forms in areas of water – low energy areas – peat bogs that formed in deep glacial depressions – swamps and bogs.  Along the coast, the flat expanses of shoreline peat had oxygen twice a day from tides, water soluble and also from air and had a thick vegetation crust, Spartina – cord grass or salt meadow hay.  Because of the green coloration, they no doubt resembled meadows of pasture grass.  Access to oxygen made sulfide residues lower, washed by tides and bathed in oxygen, thick Spartina meadows were now valuable and salt hay operations occurred, even eliminating water from the peat at times to improve harvests.  They also occurred in low energy areas, so in time they filled up with organic matter, broke the surface and could support plants – grass.
 
Here, a valuable hay crop could be harvested by established meadows that need not be cleared – relatively level and cut by cut with modified terrestrial cutters.  Eliminating the water at harvesting would create dikes in many coastal towns.  But this peat deposit had energy at times, removing hay that died back (detritus), replacing oxygen and washing away sulfides.  This peat bog would be different than the fresh water Sphagnum species that covered inland peat bogs.  This vegetation could be harvested and renewable (up to a point, extreme draining could cause marsh levels to sink as sulfate reduction consumed the base peat).  Although salt marshes were subject to bacterial reduction in oxygen six months of the year, this pathway was "cold" and bacterial reduction, therefore, slowed.  The oxygen-poor environment below the surface sustained sulfur reduction, which was already slow.  So, marshes could build up slowly as long as they obtained plant materials from land and salt marshes could hold it before leaving into more energy prone habitats.  Although much focus has been placed upon nitrogen pollution damaging salt marshes, a greater impact is heat and bacterial sulfate reduction.   Most rain delivered nitrogen, which is flushed out of bays and coves and impacts subtidal areas rather than marshes.  Here, plants would develop that could withstand the heat, high sulfides from sulfate reduction and the cold sub-zero temperatures of winter.  In times of heat (and greater sea level rise), gathering land organics allowed marshes to rise up faster in cold bacteria; growth slows, marshes became firm and peat/root density increased.  Cutting salt hay in the literature appears to strengthen the monoculture, creating root densities as to shut out other species, including some invasive.  Salt hay farmers would comment on this and in areas where salt hay is still occurring today typically have less Phragmites intrusion (harvesting salt hay actually causes root thickening.  This is also experienced in the cutting of lawn grass or commercial turf fields).
 
A rising sea level now made the accumulation of terrestrial material more critical (although many salt marsh papers continue to mention organic base material consisted of only marine algae, they consistently ignore the inputs of organic matter from land floods/hurricanes that, at times, overwhelmed bacterial capacity to reduce it (try putting five feet of compost over a section of lawn and counting the months before it is consumed even with oxygen-requiring bacteria).  It is the terrestrial organics swept by land that collected in low energy depressions along our coast.  Nichols, 1920, has conducted a review of early salt marsh cores and found at the base freshwater plant material, not marine algae.
 
One of the most curious discoveries of George Nichols 1920's Vegetation Investigations was a series of extensive marine cores (vertical borings or plugs) in New England coastal coves. The bottom of such cores and salt marsh had no eelgrass remains as he surmised should be contained in these samples. It was a New Haven core that was most noteworthy. It was the most perplexing to him, and on pages 543-544 is found this section:
  
"Assuming the vertical or historic order of succession during the development of the marsh to have been coordinate with the present day lateral sequence of zones, as set forth in the second paragraph above, the peaty and mucky deposits underlying a salt marsh should show approximately the following sequence of layers, from below upward: (1) a layer of silt, with remains of eelgrass, extending from a variable depth to low tide level; (2) a layer of silt, with but few vegetable remains, extending from low tide level up to the level at which the salt marsh grass becomes established; (3) a layer of muddy peat with more or less abundant remains of salt marsh grass, extending upward nearly to mean high tide level; (4) a layer of peat made up largely of the remains of salt marsh peat along the New England coast has revealed a very different state of affairs. Bartlett ('09), for example, describes a salt marsh near Woods Hole in which the salt marsh peat near the surface is underlain the remains of a former Chamaecyparis bog, the stumps of large numbers of trees being preserved in situ.  C.A. Davis ('10) reports that in the vicinity of Boston, the peat deposits underlying the salt marshes likewise consist, in many cases, of the remains of fresh water vegetation; in other cases peat deposits composed largely of the remains of salt meadow grasses extend from the surface downward to a depth below that of mean low tide level- in other words, to a depth many feet lower than that at which the plants which formed peat could possibly have grown. In no case, Davis emphatically states, does the peat show the hypothetical arrangement of layers specified above. The peat underlying a brackish meadow near New Haven, and sectioned during operations for brick clay, shows similar conditions: just beneath the surface (2) a layer of Distichlis peat and (3) a layer made up largely of cat-tail and fern remains, with (4) numerous scattered stumps resting in place on the underlying gravelly substratum, about five feet below the present mean high tide level.
 
From the foregoing observations it is clear that any assumed agreement between the present-day zonation of salt marsh associations in relations to tide levels and the succession of plant associations which has ensued during the development of the marshes, along the New England coast, is not in harmony with the facts as recorded by the underlying peat deposits, in so far as these records have been made available."
 
The absence of eelgrass from these cores nearly a century ago is today the subject of habitat questions today is our dominant eelgrass strain present today actually native to our shores?
 
The first time I heard this theory I was meeting with John C. Hammond, a retired oyster "planter" on Cape Cod. He had been studying the impact of Eelgrass and a more recent seaweed invader, Codium, upon cultured oysters for decades, they both don't belong here, I can recall him saying the Codium (also called dead man's fingers) invasion was easy for me to believe; I had never seen anything like it growing up in Madison, CT- eelgrass was different, I had seen it, after storms the Hammonasset Beach wrack line was full of it, and it would fill menhaden gill nets set for lobster bait.  It was 1982 and shortly after arriving on Cape Cod I would meet Mr. Hammond in Chatham many times. In reality I was sent by an organization of shell fishermen on Cape Cod to seek him out about shell fish habitat conditions and nitrogen concerns. It would be the first of many meetings.
 
To put it bluntly, Mr. Hammond had no use for either eelgrass or Codium, both in his opinion had damaged shellfish habitats; Mr. Hammond blamed eelgrass for ruining hard clam quahog bottoms (habitats) and Codium had caused much additional cleaning of harvested cultured oysters.  At the time Codium (slightly buoyant) had grown so dense as to lift oyster pond oysters off the bottom, or at least had added so much resistance they were carried out on ebb tides to sea.  The issue regarding eelgrass and hard clam habitats raised by Mr. Hammond came to an open conflict with shell fisheries on Cape Cod.   Mr. Hammond reported to me that growths of eelgrass had overrun hard clam habitats in Pleasant Bay in the 1960s.  Pleasant Bay efforts to control the spread of eelgrass even then included the use of powerful herbicides."
 
Sea level rise had a tremendous impact and now consumed marshes (and the shoreline for that matter) as energy increased drowning marshes in oxygen and sweeping organics away.  This action would impact shellfish and eelgrass living at the edge of this land sea battlefield.  As salt marshes eroded, shellfish beds could live, at times, in organics, especially oysters.  But these oysters lived in an ever changing habitat governed by organic deposition.  In many areas, oysters grew long and thin, trying to keep above a growing marine compost.
 
Shellfish beds near the shore, over time, could come and go guided mostly by climate, which included land terrestrial impacts as well.  At times, floods could send tons of organic matter downstream, collecting in areas of low energy in hot climate cycles.  Most of the salt marshes have a tannin signature – the remnants of terrestrial organic matter, and not all algae (as previously reported).  Algae is easily broken down, (it does not contain lignin) is in the active volatile oxygen zone, food for shellfish and plankton filter feeders like menhaden.  Storms and waves could move it as well.  Imagine great pools of algae collected in a thick soup as a basin in salt marsh creation.  Terrestrial inputs appear to be the largest components – compost from land.  Other areas tend to collect dead algae and if dredged tend to collect this jelly that fishers often call black mayonnaise.  Not only was sea level rising but marshes themselves were "sinking," being consumed by bacterial reduction.  This perplexed early marsh observations and core studies.  They found "marshes" far below the current sea level as reported by Nichols for Connecticut marshes in 1925.
 
Species Can Indicate Climate Conditions
 
Like oysters that also face burial in organic litter, the long thin "dog" oysters grow to keep ahead of gathering organics.  Oyster fishers are quick to recognize this shape with, at times, just the mantle sticking out of a growing upward organic material.  These are the huge oysters that Casner describes in the Maine Damariscotta River.  Long, thin and large oysters that grew during heat and gradual burial, a period of cold and storms, would destroy these beds, producing rounder, shorter oysters in a cooler more active period.  Shell middens that reflect size changes could be important indicators of climate - larger longer oysters indicate habitat stability, a sudden switch to smaller rounder oysters indicates cooler and more energy.  
 
We have histories from the Connecticut oyster industry of great storms clearing shells in off-shore reefs and burial in heat by organics (See EC #14).  Those reefs show changes in shell size and shape (personal communication, John Volk).  Eelgrass also has a habitat history of succession, trapping organic particles and shedding leaf litter stems, such as Phragmites reed, a likely invasive strain from Mongolia (See IMEP #18 Parts 1 and 2, posted June 19, 2014, The Blue Crab Forum^TM), which persists a very long period and gets trapped by any vegetation or wood branches (sometimes trees) carried into estuaries by rainwater/floods. 
 
Tidal restrictions can speed up habitat succession and changes in species richness and diversity.  This organic matter collects in low energy areas as some of my 1970's Florida Institute of Technology classes described the Tampa Bay Effect - here in a natural low energy area, causeways had reduced flushing exchange and a greasy deposit (sulfidic muck) had accumulated – the precursor of peat.  Eelgrass also reduces energy – it reduces the holding capacity of water, causing particulate organic matter (POM) to settle.  It is a "peat" builder even under the surface.
 
In fact, the eelgrass became so destructive to hard shell clam habitats that the fishers on Cape Cod declared war upon it, asking state Massachusetts researchers to control it (conversations with Sherril Smith, Fisheries Extension Agent, Massachusetts Division of Marine Fisheries, 1981-1983), including pelleted herbicides and gas-powered mowing machines.  The habitat successive nature of eelgrass was mentioned in several State of Massachusetts natural resource bulletins during this period (Much thanks to the Massachusetts Office of Coastal Zone Management for photocopying the entire series.  I used to review these bulletins with Sherril Smith in DMF offices when I worked for the Cape Cod Cooperative Extension Service).  That is what eelgrass does; it binds and holds loose particulate organic matter (POM) and it is this tendency that eelgrass meadows in low energy areas "rise," trapping leaves and smothering shellfish below, they help form a peat.  In a 1982 hydraulic clam survey of Pleasant Bay (small skiff dredge prototype), numerous eelgrass beds had dead hard shell clams underneath them. 
 
Oyster reefs show this upward successive pattern as well, building upon generation after generation, growing upward and trapping organics in a race to stay on top.  Oyster reefs, tens of feet high, could be made this way, building upon a growing shell base.  In time, shell pieces fall from dead oysters as the reef builds up and forms a solid matrix of buried shells.  In time, older oysters contribute to base and form "bars" at the mouth or rivers and bays.  The first dredging projects in colonial history were often removing oyster bars at river mouths.  In 1981, an oyster bar was discovered at the mouth of the Connecticut River and records showing oyster beds before dredging and breakwater placement.  Some of the Chesapeake Bay records mention these oyster reefs as hazards to navigation.  Some oyster reefs are made from shell hash, pieces of shells driven by storms, which acted to collect on the sand bars (sand waves), such as the New Haven natural bed before breakwaters were built.  Here, storms destroyed wharfs and rivers but cast shells in ridges, especially the light shell of the Anomia simplex, called jingle shells, which obtained oyster sets "on the jingles" according to George McNeil in New Haven Harbor.  
 
Energy governed the ecology of these reefs in a successive pattern, growing, maturing or dying (burial) over hundreds of years.  Hurricanes could end one reef while rinsing the shells, pushing them into hills that would begin another bed.
 
Oysters in rivers, however, succeeded much faster due to the organics in them.  A good set of oysters could trap leaves, sticks, grass and woody tissue, called oatmeal on Cape Cod.  This organic litter could bury oysters in just a few years, leaving a series of long oysters built upon several generations.  Paul Galtsoff, in his 1964 Fish and Wildlife Bulletin, carefully excavated a reef section and picture on page 20 figure 19 is a section of a reef about two feet high.
 
Organics do govern the ecology of these reefs, which succeed and have a habitat history buried below the living oysters.
 
That is what happens with eelgrass, believing once that this type of habitat is helpful to bay scallops, but over time, it is not.  Bay scallops require clean, rinsed marine soils, alkaline pH and a corraline red plant (species).  As bay scallops, eelgrass habitat clocks overlap as habitat is declining for bay scallops; they will set on it but prefer corraline reds, which emits a chemical when torn in a storm (the bleeding grass syndrome) and attracts bay scallops to live near it.  Corraline algae contains gonad stimulants, both of which eelgrass does not.  It is the storm cultivation and ripping of corraline reds that perhaps signal scallops to set heavily on these algal growths.  When I told George McNeil about our seed scallop transplants in 1978, he asked why I had picked eelgrass.  I told him that all the reports I had read mentioned bay scallops needing it.  He chuckled "Well," he said "perhaps some do but that is the last place I would put the scallops."  I had heard stories about Clinton Harbor scallops, but George told me that was around the turn of the century and the outer harbor and not the inner harbor where the eelgrass was and presently.  In fact, the eelgrass is the least type of habitat and one that buried a bed of softshell clams decades ago.  He urged me to look under the eelgrass, which I did and found exactly what Mr. McNeil described – about three to four feet below was the remains of very old softshell clams and a strong sulfide smell.  Later, I found articles in the local newspaper that the inside Clinton Harbor had once had a huge set of softshell clams but a barrier inlet, called the Dardanelles, had been closed and the area filled in over time. 
 
It is natural for eelgrass to transition habitats and acidify marine soils, making them in time toxic to clam larvae.  The shellfishers watched this happen, but in the end all eelgrass control treatments were ineffective (See IMEP #30, posted October 9, 2014, The Blue Crab Forum^TM Fishing, Eeling and Oystering thread). 
 
In 1978, I assisted with the transplanting of bay scallop seed into Clinton Harbor.  It was George McNeil who pointed out the eelgrass meadow wasn't natural.  The real bottom was below some three feet of leaf rot.
 
Salt marshes (peat), oyster reefs and eelgrass meadows were largely governed by temperature, energy and sea level rise.  All would rise in response to organics in heat and fall victim to energy (sea level rise) in cold.  The temperature of the seawater would largely govern which bacterial "pathway" would "win" and exposes a weakness in the habitat history of salt marshes today.  With sea level rise and heat, the cold/oxygen pathway collapses.  The marshes "burn" in a slow reduction pathway (although in times of heat, even peat can burn undergrown.  I was exposed to this in Florida, waking to an orange hazy reddish glow from Everglades muck fires) and create toxic residues – from sulfate reduction, low oxygen conditions add to this sulfur-killing zone, adding toxic chemicals, compounds and acids (mostly sulfuric) as fish kills mount in high temperatures. 
 
Although most of blame for these kills is reported to be low oxygen and that is correct, but fails to mention sulfide compounds until people report the rotten egg smells of the last century.  Many people have not dealt with the century ago "great heat" but here in New England, it became extremely hot – free range or barnyard chickens often would hide eggs and in winter were easily collected without concern, but in summer the protective bacteria coating failed and, in high heat, bacterial reduction occurred and sealed from oxygen produced hydrogen sulfide.  As a young boy I watched my aunts crack an egg into a separate bowl before adding them to a cake mix.  Although the period of this heat had long since passed, the memory of rotten eggs does leave an impression. 
 
Even today, many fish kill reports mention the smell of rotten eggs as a characteristic symptom.  That is why salt marsh, eelgrass and oyster habitat histories have this tendency to rise over long periods of time, they collect organics and form a layer of organic peat, that once sealed from oxygen, becomes a sapropel.  Our area is rich in the mineral iron (Fe), so black iron sulfide is the color of sulfide-rich sapropel.  It is in sapropel that carbon is banked and why it was used as a carbon additive to Connecticut soils.  The sulfur from bacterial digestion is how sulfur got into "coal" as it is simply fossilized sapropel.
 

Appendix #1

Anaerobic oxidation of methane alters sediment records of sulfur, iron and phosphorus in the Black Sea

Biogeosciences, 13, 5333-5355, 2016

Matthias Egger, Peter Kraal, Tom Jilbert, Fatimah Sulu-Gambari, Célia J. Sapart, Thomas Röckmann, and Caroline P. Slomp

 

 

Abstract. The surface sediments in the Black Sea are underlain by extensive deposits of iron (Fe)-oxide-rich lake sediments that were deposited prior to the inflow of marine Mediterranean Sea waters ca. 9000 years ago. The subsequent downward diffusion of marine sulfate into the methane-bearing lake sediments has led to a multitude of diagenetic reactions in the sulfate-methane transition zone (SMTZ), including anaerobic oxidation of methane (AOM) with sulfate. While the sedimentary cycles of sulfur (S), methane and Fe in the SMTZ have been extensively studied, relatively little is known about the diagenetic alterations of the sediment record occurring below the SMTZ.
 
 Here we combine detailed geochemical analyses of the sediment and porewater with multicomponent diagenetic modeling to study the diagenetic alterations below the SMTZ at two sites in the western Black Sea. We focus on the dynamics of Fe, S and phosphorus (P), and demonstrate that diagenesis has strongly overprinted the sedimentary burial records of these elements. In line with previous studies in the Black Sea, we show that sulfate-mediated AOM substantially enhances the downward diffusive flux of sulfide into the deep limnic deposits. During this downward sulfidization, Fe oxides, Fe carbonates and Fe phosphates (e.g., vivianite) are converted to sulfide phases, leading to an enrichment in solid-phase S and the release of phosphate to the porewater. Below the sulfidization front, high concentrations of dissolved ferrous Fe (Fe²⁺) lead to sequestration of downward-diffusing phosphate as authigenic vivianite, resulting in a transient accumulation of total P directly below the sulfidization front.
 
 Our model results further demonstrate that downward-migrating sulfide becomes partly re-oxidized to sulfate due to reactions with oxidized Fe minerals, fueling a cryptic S cycle and thus stimulating slow rates of sulfate-driven AOM ( ∼  1–100 pmol cm⁻³ d⁻¹) in the sulfate-depleted limnic deposits. However, this process is unlikely to explain the observed release of dissolved Fe²⁺ below the SMTZ. Instead, we suggest that besides organoclastic Fe oxide reduction and reactivation of less reactive Fe oxides by methanogens, AOM coupled to the reduction of Fe oxides may also provide a possible mechanism for the high concentrations of Fe²⁺ in the porewater at depth. Our results reveal that methane plays a key role in the diagenetic alterations of Fe, S and P records in Black Sea sediments. The downward sulfidization into the limnic deposits is enhanced through sulfate-driven AOM with sulfate, and AOM with Fe oxides may provide a deep source of dissolved Fe²⁺ that drives the sequestration of P in vivianite below the sulfidization front.
Published by Copernicus Publications on behalf of the European Geosciences Union.
 

Appendix #2

 

 

Robertson, A.H.F., Emeis, K.-C., Richter, C., and Camerlenghi, A. (Eds.), 1998 Proceedings of the Ocean Drilling Program, Scientific Results, Vol. 160

 

25. THE RESPONSE OF BACTERIAL POPULATIONS TO SAPROPELS IN DEEP SEDIMENTS OF THE EASTERN MEDITERRANEAN (SITE 969)¹

 

B.A. Cragg,² K.M. Law,² A. Cramp,³ and R.J. Parkes²

 

 

ABSTRACT

 
Sediment samples were obtained from 36 depths between the near-surface to almost 100 mbsf (meters below seafloor) at Site 969, south of Crete. Bacterial populations were determined by the acrinine orange direct count technique. The bacterial profile agreed with a general relationship between sediment depth and bacterial concentration previously obtained from a range of different marine sites. Bacterial populations decreased from a near-surface value of 7.76 × 10⁸ cells/cm3 to 1.0 × 10⁶ cells/ cm³ by 97.79 mbsf. Dividing and divided cell numbers roughly paralleled total bacterial numbers representing ~9.9% of the total population. At two depths, sapropels were specifically sampled in duplicate and enumeration suggested that bacterial populations within sapropels were homogeneous. Two additional sapropels were also encountered by chance. The data strongly indicated an active and probably growing bacterial population within the sapropels because:
 
1. Bacterial populations were considerably, and significantly, greater than     those in adjacent nonsapropel sediment layers.
2. There were locally high TOC concentrations and abundant electron acceptors (sulfate).
3. Evidence of postburial bacterial sulfate reduction activity was supported by independent sulfur isotope data.
4. Dividing bacterial cells were present.
 
These results demonstrate the surprising ability of 4.7 Ma organic matter to continue to provide energy for bacterial populations during burial, and this supports the global presence of a deep bacterial biosphere in marine sediments.
 

INTRODUCTION

 
The presence of a deep bacterial biosphere in marine sediments has now been confirmed by a large amount of work, primarily on Ocean Drilling Program (ODP) sediments (Whelan et al., 1986; Tarafa et al., 1987; Parkes et al., 1990, 1993, 1994, 1995; Cragg, 1994; Cragg et al., 1990, 1992, 1995a, 1995b, 1996, 1997; Cragg and Parkes 1994; Cragg and Kemp, 1995), and recent work indicates a bacterial presence in basaltic basement rocks (Furnes et al., 1996; Giovannoni et al., 1996). The depth profile of sediment bacteria is remarkably consistent across different oceans and shows population sizes of ~ 9 × 108 cells/cm³ at the near surface decreasing exponentially to ~1.5 × 106 cells/cm3 at 500 mbsf. In near-surface marine sediments, bacteria play a central role in the degradation and selective preservation of organic matter and are thus intimately involved in biogeochemical cycling of elements (Jorgensen, 1983; Novitsky and Karl, 1986; Jorgensen et al., 1990; Parkes et al., 1993). At greater depths, geochemical evidence has indicated that bacterial populations remain active (Krumbein, 1983), and more recently low levels of bacterial activity have been demonstrated to 500 mbsf in the Japan Sea (Cragg et al., 1992; Getliff et al., 1992; Parkes et al., 1994). Sediment cores from the Mediterranean Sea contain numerous dark bands that are rich in organic carbon and contain above average amounts of pyrite (Rohling, 1994). These layers, called sapropels, are characteristic of silled marginal seas and seem to have occurred in response to significant changes in climate, circulation, and biogeochemical cycling (Emeis, Robertson, Richter, et al., 1996). A number of models exist to explain sapropel formation, from isolation and subsequent anoxia of deep bottom water, resulting in enhanced organic carbon preservation (Vergnaud-Grazzini et al., 1986).
 

Appendix #3

 

Carbon Credits and Pollution Allowances

 

"Regional Greenhouse Gas Initiative RGGI"

 

Department of Energy & Environmental Protection

Regional Greenhouse Gas Initiative (RGGI)
 
RGGI is a cooperative effort among the states of Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, Vermont, and Virginia (RGGI states) to cap and reduce power sector CO₂ emissions. RGGI is the nation's first mandatory, market-based CO₂ emissions reduction program. Within the RGGI states, fossil-fuel-fired electric power generators with a capacity of 25 megawatts or greater must hold allowances equal to their CO₂ emissions over each three-year control period. Generators must also hold allowances equal to 50% of their emissions during each interim control period (the first two calendar years of each three-year control period). The current three-year control period is January 1, 2021 to December 31, 2023.
 
 RGGI is composed of individual CO₂ budget trading programs in each participating state. Through independent regulations, based on the RGGI Model Rule, each state's CO₂ budget trading program limits CO₂ emissions from generators, issues CO₂ allowances, and establishes participation in the quarterly RGGI auctions. The RGGI states invest the majority of auction proceeds toward energy efficiency initiatives, renewable energy deployment, direct greenhouse gas emissions reductions strategies, and direct bill assistance for low-income ratepayers.  As of December 2021, Connecticut has received nearly $285.8 million in auction proceeds since the program's inception in September 2008. Nearly 70% of Connecticut's auction proceeds are invested in energy efficiency programs administered by the electric distribution companies and municipal electric utilities. 23% of auction proceeds are invested by the Connecticut Green Bank to finance the deployment of Class I renewable resources. 
 
 
Amendment of Section 22a-174-31 of the Regulations of Connecticut State Agencies (RCSA)
On November 8, 2018, Connecticut proposed an amendment of Section 22a-174-31 of the RCSA to reflect the conclusions of a thorough program review process conducted by the RGGI states and stakeholders in accordance with a RGGI Memorandum of Understanding, and completed in December of 2017. The program review sought to continue the goal of effectively reducing CO₂ emissions while providing benefits to consumers and the region, and to address the issue of overcapacity of allowances relative to actual emission levels in the region.
"Northeast US carbon dioxide emissions prices return to last year's high"
US Energy Information Administration
Principal contributor: O. Nilay Manzagol
 
The most recent auction of carbon dioxide (CO₂) emissions allowances in the major U.S. northeast regional trading hub reached near record-high prices, as the number of allowances available was reduced. The latest Regional Greenhouse Gas Initiative (RGGI) quarterly auction, held September 6, 2023, resulted in a clearing price of $13.85 per ton for CO₂ emissions allowances, surpassing the previous quarter's clearing price by 9% and nearing the record price, $13.90 per ton, set in March 2022. Allowance prices have been increasing since RGGI's March 2023 auction as fewer allowances have been made available over time.
Launched in 2009, RGGI is a cooperative effort among 12 eastern states to reduce CO₂ emissions from power plants. States involved in RGGI include Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, and Virginia, though Pennsylvania's RGGI regulation is under a court injunction, so the state will not release any allowances until further notice.
Participating states establish a regional cap on CO₂ emissions from regulated power plants. The states require that power plants purchase one CO₂ allowance for each short ton of carbon they emit. RGGI offers new carbon allowances through quarterly regional CO₂ allowance auctions, where a set number of allowances are sold. These auctions are sealed-bid, uniform price auctions open to all qualified participants that result in a single quarterly clearing price. RGGI reduces the number of allowances available in auctions over time in order to reduce regional emissions and adjusts the total to take into account unused allowances from earlier auctions. These changes to the cap on the number of allowances have been put upward pressure on allowance prices.
For 2023, RGGI's adjusted regional cap on emissions to be sold in four auctions for the 12 member states totals allowances for 168.9 million short tons of CO₂. After removing Pennsylvania, the adjusted cap for the remaining 11 participating states totals allowances for 93.4 million short tons of CO₂.
The RGGI states decided to adjust the cap for unused allowances starting in 2012 after experiencing successive years of large surpluses, due to the assumptions at the program's outset that natural gas prices would remain high and growth in electricity demand would continue.
In the September 2023 auction, RGGI sold allowances for 21.9 million short tons of CO₂ emissions. RGGI states invest most of the auction proceeds in consumer benefit programs to improve energy efficiency, accelerate the deployment of renewable energy technologies, and support consumer electricity assistance programs. Auction proceeds totaled $303.9 million in the September auction and have totaled $6.7 billion since inception of the auctions in 2009.

In addition to purchasing allowances at auction, entities can also trade allowances on secondary markets, either directly via over-the-counter trades with third parties or through futures contracts traded on exchanges. Secondary markets give firms the ability to obtain CO₂ allowances at any time during the three months between the RGGI auctions, allowing firms to protect themselves against the potential volatility of future auction clearing prices, and provide a basis to make investment decisions in markets affected by the cost of RGGI compliance.