Optical transparency, chlorophyll and primary productivity in the eastern mediterranean near the israeli coast

Abstract

For the first time, quantative data on optical characteristics, chlorophyll standing crops and primary production are given for the pelagie waters of the Levant Basin in the Eastern Mediterranean, close to the Israeli coast. During 4 cruises (July, December 1981, April and July 1982) we measured Secchi depths ranging from 33 to 46 rn, diffuse downwelling attenuation coefficients from 0.031 to 0.046 rn1, near-surface chlorophylls from 0.026 to 0.069 J.tg .11 and photosynthetic rates from 1.62 to 9. 79 mg C.mh • Images from the Coastal Zone Col or Scanner on board the Nimbus 7 Satellite confirmed that these low chlorophyll concentrations were characteristic for the pelagie region and suggested that mixing with the neritic waters may occur in winter. The majority of chlorophyll and primary productivity was associated with organisms < 3 J.tm. Deep chlorophyll maxima (75 to 125 rn) were observed at ail pelagie stations. We note that these waters are among the most oligotrophic described.