engleski

Estimating contribution of coastal-trapped internal waves to primary production: a case study of Lastovo Island (Adriatic Sea)

The effect of internal waves on primary production has not been studied extensively, with only a minor number of publications on the topic, all of which conclude that internal waves can increase daily primary production by a factor of less than 10%. Here we examine a special case of resonant excitation of internal waves around specific topographical features, like islands and its effect on primary production. The entrapment of these waves due to resonance can last for a considerable amount of time, ranging from a few days to weeks. First we explore the physical setting which leads to generation and resonant endurance of island trapped internal waves. Then we proceed to investigate mathematical formulations of biological models suitable for dealing with this phenomenon and our research. The analysis reveals that enhancement of primary production occurs if internal waves and the diurnal cycle of irradiance are in phase, whereas weakening of primary production occurs in case of internal waves and the diurnal cycle of irradiance being out of phase. Biomass accumulation is in accordance with literature values on the daily scale, but is stronger the longer the wave resides around the island. In this sense, geometry of some islands can localy increase primary production due to resonant excitation of internal waves. One of locations where longlasting entrapment of gravity waves is known to happen is Lastovo Island, in the Mid Adriatic Sea, where internal gravity waves can persist up to a week. The theoretical model is further developed for Lastovo Island, and validated using coupled ocean-biology Regional Ocean Modelling System (ROMS) and available data.

internal waves ; primary production ; island effect ;

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