Marine mucilage, also referenced as sea snot or sea saliva, is thick, gelatinous organic matter found around the world's oceans, lately observed in the Mediterranean Sea.
Marine mucilage carries diverse microorganisms. Triggers that cause it to form include increased phosphorus, drought conditions, and climate change. Its effects are widespread, affecting fishing industries, smothering sea life, and spreading bacteria and viruses. Citizens and governments around the world are working to institute countermeasures, including treatment, seawater cleanup, and other public policies.
Marine mucilage has many components, including diverse microorganisms including viruses and prokaryotes, debris, proteins, minerals, [1] and exopolymeric compounds with colloidal properties. [2] Although various historical definitions have not consolidated, it is agreed that mucilages are complex chemical substances, as well as complex natural materials. Its composition can change over time.
Marine mucilage appears following an increase of phosphorus. In one 2021 case phosphorus values were three to four times higher than the previous year. Other excess nutrients [4] combined with drought conditions and prolonged warm sea temperatures and calm weather contributed. Marine mucilage is also produced by phytoplankton when they are stressed. [1]
Anthropogenic global climate change is likely increasing marine mucilage. [5] Warmer, slower moving waters increase production and allow it to accumulate in massive sheets. In the Mediterranean Sea, the frequency of marine mucilage events increases with warm temperature anomalies. [2]
Marine mucilage is a natural occurrence in marine environments, but its presence in excessive amounts can indicate environmental stress and poor water quality. Biogeochemistry plays a crucial role in the formation and dynamics of marine mucilage. Factors such as nutrient availability, temperature, salinity, and microbial activity influence the production and degradation of organic matter that contributes to mucilage formation. Excessive nutrients, often from Anthropogenic sources such as agricultural runoff and wastewater discharge, can accelerate phytoplankton growth and mucilage formation, leading to eutrophication.
Understanding how mucilage interacts with biogeochemistry is vital for monitoring and managing coastal ecosystems. Recent studies have utilized advanced remote sensing techniques, such as Sentinel-2 satellite imagery, to map mucilage distribution and assess environmental conditions. These images, combined with advanced processing techniques, allowed them to notice subtle changes in water quality and identify areas affected by mucilage accumulations. Through the use of spectral indices such as Normalized Difference Turbidity Index (NDTI), Normalized Difference Water Index (NDWI), and Automated Mucilage Extraction Index (AMEI). By employing spectral indices and deep learning methods like Convolutional Neural Networks (CNNs), researchers can improve mucilage detection over large areas. [6] By integrating remote sensing data with biogeochemical models and field observations, researchers can gain insight into the underlying mechanisms that drive mucilage formation and develop strategies to mitigate its effects on coastal environments.
The carbon cycle is affected by the marine mucilage. The release of dissolved organic carbon (DOC) from mucilage contributes to the organic carbon reserve in the marine ecosystem. This infusion of organic carbon stimulates the growth and metabolism of microbial communities in and around the mucilage. As these microbes consume DOC, they respire and convert organic carbon into carbon dioxide (CO2) through microbial respiration. This cycle contributes to the exchange of CO2 between the ocean and the atmosphere, potentially affecting atmospheric CO2 levels and global carbon budgets. [7]
Mucilage events affect the efficiency of the biological pump, a vital mechanism in the ocean carbon cycle. The biological pump explains how carbon moves from the ocean surface to its depths through the sinking of organic particles such as marine snow and phytoplankton. By trapping organic matter and microorganisms, mucilage can accelerate the sinking rate of organic particles and facilitate their transfer to deeper ocean layers.
Marine mucilage was first reported in 1729.[ citation needed ]
The Deepwater Horizon oil spill in the Gulf of Mexico created large amounts of marine mucilage. Scientists are not sure of the mechanism for this, but one theory asserts that a massive kill of microscopic marine life created a "blizzard" of marine snow. Scientists worry that the mass of marine mucilage could pose a biohazard to surviving marine life in the area. Marine mucilage left by the spill likely resulted in the loss of sea life in the Gulf, as evidenced by a dead field of deepwater coral 11 kilometers from the Deepwater Horizon station. [8]
The Mediterranean experienced the worse effects of marine mucilage in 2021.[ clarification needed ] Exponential growth afflicted the Mediterranean and other seas. [2] In early 2021, marine mucilage spread in the Sea of Marmara, due to pollution from wastewater dumped into seawater, which led to the proliferation of phytoplankton, and threatened the marine biome. The port of Erdek at the Sea of Marmara was covered by mucilage. Turkish workers embarked on a massive effort to vacuum it up in June 2021. Yalıköy port in Ordu Province witnessed accumulating mucilage in June 2021, in the Black Sea. [9] Fines were issued to companies discovered to be dumping wastewater. [4]
Increasing marine mucilage has become an issue in public health, economic, and environmental matters. Excessive marine mucilage was observed as early as 2009.
While marine mucilage is not toxic to humans, public health concerns are associated with it. Due to its complex makeup, marine mucilage contains pathogenic bacteria and transports marine diseases. [2] The majority of such diseases affect both marine invertebrates and vertebrates. [2]
Marine mucilage has had an impact on economies around the world, especially those that revolve around the Mediterranean. Marine mucilage has long been seen as a nuisance to the fishing industry, as it clogs fishing nets. [2] Coastal towns that rely on tourism suffer from unappealing waters. Marine mucilage produce an offensive smell and makes the ocean unsuitable for bathing. [2]
Marine mucilage can coat the gills of sea creatures subsumed in it, cutting off oxygen and killing them.[ citation needed ] Marine mucilage floating on the surface also can significantly limit sunlight that nourishes coral and vegetation.[ citation needed ]
Countermeasures include collecting marine mucilage from the sea surface and laying barriers on the sea surface to prevent it from spreading. Long-term countermeasures include improving wastewater treatment, creating marine protected areas, and limiting climate change. [4] Another approach involves attracting activity such as tourism that prevents the water from stagnating for long periods. Introducing marine species that can consume excessive nutrients.
Plankton are the diverse collection of organisms found in water that are unable to propel themselves against a current. The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish, and baleen whales.
Phytoplankton are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words φυτόν, meaning 'plant', and, meaning 'wanderer' or 'drifter'.
The biological pump (or ocean carbon biological pump or marine biological carbon pump) is the ocean's biologically driven sequestration of carbon from the atmosphere and land runoff to the ocean interior and seafloor sediments. In other words, it is a biologically mediated process which results in the sequestering of carbon in the deep ocean away from the atmosphere and the land. The biological pump is the biological component of the "marine carbon pump" which contains both a physical and biological component. It is the part of the broader oceanic carbon cycle responsible for the cycling of organic matter formed mainly by phytoplankton during photosynthesis (soft-tissue pump), as well as the cycling of calcium carbonate (CaCO3) formed into shells by certain organisms such as plankton and mollusks (carbonate pump).
A biogeochemical cycle, or more generally a cycle of matter, is the movement and transformation of chemical elements and compounds between living organisms, the atmosphere, and the Earth's crust. Major biogeochemical cycles include the carbon cycle, the nitrogen cycle and the water cycle. In each cycle, the chemical element or molecule is transformed and cycled by living organisms and through various geological forms and reservoirs, including the atmosphere, the soil and the oceans. It can be thought of as the pathway by which a chemical substance cycles the biotic compartment and the abiotic compartments of Earth. The biotic compartment is the biosphere and the abiotic compartments are the atmosphere, lithosphere and hydrosphere.
The iron cycle (Fe) is the biogeochemical cycle of iron through the atmosphere, hydrosphere, biosphere and lithosphere. While Fe is highly abundant in the Earth's crust, it is less common in oxygenated surface waters. Iron is a key micronutrient in primary productivity, and a limiting nutrient in the Southern ocean, eastern equatorial Pacific, and the subarctic Pacific referred to as High-Nutrient, Low-Chlorophyll (HNLC) regions of the ocean.
The Redfield ratio or Redfield stoichiometry is the consistent atomic ratio of carbon, nitrogen and phosphorus found in marine phytoplankton and throughout the deep oceans.
Ocean fertilization or ocean nourishment is a type of technology for carbon dioxide removal from the ocean based on the purposeful introduction of plant nutrients to the upper ocean to increase marine food production and to remove carbon dioxide from the atmosphere. Ocean nutrient fertilization, for example iron fertilization, could stimulate photosynthesis in phytoplankton. The phytoplankton would convert the ocean's dissolved carbon dioxide into carbohydrate, some of which would sink into the deeper ocean before oxidizing. More than a dozen open-sea experiments confirmed that adding iron to the ocean increases photosynthesis in phytoplankton by up to 30 times.
Picoplankton is the fraction of plankton composed by cells between 0.2 and 2 μm that can be either prokaryotic and eukaryotic phototrophs and heterotrophs:
The microbial loop describes a trophic pathway where, in aquatic systems, dissolved organic carbon (DOC) is returned to higher trophic levels via its incorporation into bacterial biomass, and then coupled with the classic food chain formed by phytoplankton-zooplankton-nekton. In soil systems, the microbial loop refers to soil carbon. The term microbial loop was coined by Farooq Azam, Tom Fenchel et al. in 1983 to include the role played by bacteria in the carbon and nutrient cycles of the marine environment.
In the deep ocean, marine snow is a continuous shower of mostly organic detritus falling from the upper layers of the water column. It is a significant means of exporting energy from the light-rich photic zone to the aphotic zone below, which is referred to as the biological pump. Export production is the amount of organic matter produced in the ocean by primary production that is not recycled (remineralised) before it sinks into the aphotic zone. Because of the role of export production in the ocean's biological pump, it is typically measured in units of carbon. The term was coined by explorer William Beebe as observed from his bathysphere. As the origin of marine snow lies in activities within the productive photic zone, the prevalence of marine snow changes with seasonal fluctuations in photosynthetic activity and ocean currents. Marine snow can be an important food source for organisms living in the aphotic zone, particularly for organisms that live very deep in the water column.
Bacterioplankton refers to the bacterial component of the plankton that drifts in the water column. The name comes from the Ancient Greek word πλανκτος, meaning "wanderer" or "drifter", and bacterium, a Latin term coined in the 19th century by Christian Gottfried Ehrenberg. They are found in both seawater and freshwater.
The North Pacific Subtropical Gyre (NPSG) is the largest contiguous ecosystem on earth. In oceanography, a subtropical gyre is a ring-like system of ocean currents rotating clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere caused by the Coriolis Effect. They generally form in large open ocean areas that lie between land masses.
Marine microorganisms are defined by their habitat as microorganisms living in a marine environment, that is, in the saltwater of a sea or ocean or the brackish water of a coastal estuary. A microorganism is any microscopic living organism or virus, which is invisibly small to the unaided human eye without magnification. Microorganisms are very diverse. They can be single-celled or multicellular and include bacteria, archaea, viruses, and most protozoa, as well as some fungi, algae, and animals, such as rotifers and copepods. Many macroscopic animals and plants have microscopic juvenile stages. Some microbiologists also classify viruses as microorganisms, but others consider these as non-living.
Particulate organic matter (POM) is a fraction of total organic matter operationally defined as that which does not pass through a filter pore size that typically ranges in size from 0.053 millimeters (53 μm) to 2 millimeters.
Marine biogeochemical cycles are biogeochemical cycles that occur within marine environments, that is, in the saltwater of seas or oceans or the brackish water of coastal estuaries. These biogeochemical cycles are the pathways chemical substances and elements move through within the marine environment. In addition, substances and elements can be imported into or exported from the marine environment. These imports and exports can occur as exchanges with the atmosphere above, the ocean floor below, or as runoff from the land.
The viral shunt is a mechanism that prevents marine microbial particulate organic matter (POM) from migrating up trophic levels by recycling them into dissolved organic matter (DOM), which can be readily taken up by microorganisms. The DOM recycled by the viral shunt pathway is comparable to the amount generated by the other main sources of marine DOM.
Compared to terrestrial environments, marine environments have biomass pyramids which are inverted at the base. In particular, the biomass of consumers is larger than the biomass of primary producers. This happens because the ocean's primary producers are tiny phytoplankton which grow and reproduce rapidly, so a small mass can have a fast rate of primary production. In contrast, many significant terrestrial primary producers, such as mature forests, grow and reproduce slowly, so a much larger mass is needed to achieve the same rate of primary production.
Human activities affect marine life and marine habitats through overfishing, habitat loss, the introduction of invasive species, ocean pollution, ocean acidification and ocean warming. These impact marine ecosystems and food webs and may result in consequences as yet unrecognised for the biodiversity and continuation of marine life forms.
Low-nutrient, low-chlorophyll (LNLC)regions are aquatic zones that are low in nutrients and consequently have low rate of primary production, as indicated by low chlorophyll concentrations. These regions can be described as oligotrophic, and about 75% of the world's oceans encompass LNLC regions. A majority of LNLC regions are associated with subtropical gyres but are also present in areas of the Mediterranean Sea, and some inland lakes. Physical processes limit nutrient availability in LNLC regions, which favors nutrient recycling in the photic zone and selects for smaller phytoplankton species. LNLC regions are generally not found near coasts, owing to the fact that coastal areas receive more nutrients from terrestrial sources and upwelling. In marine systems, seasonal and decadal variability of primary productivity in LNLC regions is driven in part by large-scale climatic regimes leading to important effects on the global carbon cycle and the oceanic carbon cycle.
Marine mucilage, also referenced as sea snot or sea saliva is thick, gelatinous organic matter found around the world's oceans, specifically in recent times in the Mediterranean Sea.