Marine snow

Fig. 2.8 Time series of mean marine snow concentration [kmolP/m3] (solid), number of aggregates [particles/cm3] (dashed), and the mean slope of the particle size distribution in the euphotic zone (solid), and number of aggregates (dashed) at 175W 55°S.

Fig. 2.21 Compartmental burden [t] (left panel), solid lines model experiment with aggregation of marine snow (AGG), dashed lines experiment with satellite assimilation (SAT). Migration of the centre of gravity of the total environmental burden (right panel). Dashed lines show the location of the COG at the end of the simulation. The COG of the SAT experiment is shown in blue, the COG of the AGG experiment in red. Circles represent monthly mean COGs.

Asper VL (1987) Measuring the flux and sinking speed of marine snow aggregates. Deep-Sea Research 34 1-17... 

Kriest I (2002) Different parameterizations of marine snow in a ld-model and their influence on representation of marine snow, nitrogen budget and sedimentation. Deep Sea Research I 49 2133-2162... 

M. Mecozzi and Zs. Papai, Application of curve fitting thin-layer chromatography-flame ionization detection analysis of the carbohydrate fraction in marine mucilage and marine snow samples from Italian seas. J. Chromatogr. Sci. 42 (2004) 268-274. 

This rate law suggests that dissolution should be relatively slow compared to the time that detrital PIC takes to settle to the seafloor. But recent observations indicate that a significant amoimt of dissolution occurs high in the water column, even in saturated waters. Dissolution imder saturated conditions is thought to be a consequence of PIC exposure to metabolic CO2 in acidic microenvironments such as found in zooplankton guts and feces and within aggregations of marine snow. 

Because of its high organic content, the marine snow acts as a microhabitat that supports enhanced rates of heterotrophic microbial activity. The associated nutrient remineralization causes the seawater within and aroimd the marine snow to be characterized by elevated nitrogen and phosphorus concentrations and low levels of O2. The importance of these suboxic and anoxic microzones to the marine cycling of the biolimiting elements is unknown but potentially significant. 

Both the refractory and labile fractions of HMW DOM can be lost from seawater through formation of macrogels that aggregate into marine snow. The labile fraction that is known to participate in marine snow formation are the TEPs, such as mucopolysaccharides found in the mucus sheaths surrounding fecal pellets and plankton colonies. HMW DOM is also lost from seawater via (1) adsorption onto sinking POM and minerals, (2) conversion into POM at the sea surfece by turbulence associated with bursting bubbles, and (3) photochemical degradation. 

Marine snow Large, loosely aggregated solids composed of biogenous and Uthogenous particles. The organic material is often colonized by microbes. 

Scientists have observed that marine snow can be a nuisance. Because in some cases gas may be produced, particles nse and create a scum, and dns can be dried by the sun to produce a surface of sufficient strength to permit seagulls to walk upon it. Such scum extends for many thousands of acres (hectares) in the Adriatic Sea. where it has become a menace to fishermen and the tourist trade. Such scums were reported as early as the 1700s. 

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