Marine Mucilage and Marine Snow (Marine Biology)

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Marine Mucilage Definitions:

Marine Mucilage Background Information:

Marine snow is present in all oceans of the world.
Surface water warming can favour the coalescence of this marine snow into marine mucilage.
Marine mucilage characteristic of aquatic ecosystems with changed environmental conditions.
The phenomenon is causing increased concern around coastal areas as a result of socio-economical consequences.
The Adriatic Sea (esp. Northern portion) within the Mediterranean basin is the most severely affected by outbreaks of massive marine mucilage.
Research evidence suggests that spreading of mucilage in the Mediterranean Sea is linked to climate-driven sea surface warming.

Marine Mucilage History:

Mucilage was reported in the Adriatic Sea for the first time in 1729.
The original description mentioned the “dirty sea” phenomenon (“mare sporco”) as it caused the clogging up of fishing nets.
From this time there have been sporadic reports of the phenomenon.
Over the last 30 years, the reported frequency of this phenomenon appears to have increased markedly.

Marine Mucilage Composition:

Made of exopolymeric compounds with highly colloidal properties that are released by marine organisms.
Phytoplankton will exude photosyntetically-derived carbohydrates when placed in stressful conditions (i.e. P-limited diatoms which produce large amounts of polysaccharides, or death & decomposition of cell-wall debris).
Prokaryotes may not be able to digest these exopolymers leading to release and further accumulation.

Marine Mucilage Consequences:

The mucilage makes seawater areas unsuitable for bathing because of the bad smell & the adherence to the skin of bathers.
The life span of the mucilage may be up to 2-3 months on the water surface or column.
Marine mucilage once it has settled on the sea bottom, coats the sediments, & may extend for kilometers - producing hypoxic / anoxic conditions.
This may then cause suffocation of benthic (bottom-associated) organisms.
The mucilage can also act as major repository for prokaryotes (i.e.bacteraia & protozoa) & viruses with the potential health risks of this.
Fingerprinting techniques also show that the mucilage has increased bacterial diversity compared with the surrounding seawater.
Fluorescence in situ hybridization (FISH) has identified Vibrio harveyi in from some marine mucilage deposits, but not in the surrounding seawater.
It is possible that the complex organic matrix of marine mucilage enables favourable microniches to develop which then support pathogen colonization & survival.

Sea "Mucus" Blobs Pose Threat (National Geographic):

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