Abstract

Few studies have compared water quality and plankton along the eutrophication gradient from Kingston Harbour to oceanic waters around Jamaica. To compare the planktonic community along the expected nutrient gradient, we sampled every two weeks at four stations, from eutrophic Kingston Harbour to oceanic California Bank. Phytoplankton was assessed from whole water Niskin bottle casts and zooplankton by vertical hauls with plankton nets of three different mesh sizes: 64µm, 200µm, and 600µm. Total phytoplankton biomass declined sharply away from the harbour (1.0 μg L-1 at the Harbour Shoal Beacon to 0.2 μg L-1 at California Bank). Characteristic estuarine phytoplankton genera -such as Ceratium, Gonyaulax, Gyrodinium and Rhizosolenia- dominated harbour samples while genera characteristic of offshore locations -such as Asterionelliopsis, Navicula, Nitzschia, Rhizosolenia and Thalassionema- dominated California Bank. Highest phytoplankton densities (mean values of 34 174 cells L-1) were found at the harbor mouth. Mean zooplankton abundances ranged from maximum (5 858.5m-3) at Beacon to minimum (2 124.2 m-3) at California; 171 species of zooplankton were identified and copepods dominated with 76 species. Overall, 75 species of zooplankton were identified from Beacon, 107 from Port Royal Cays- South East Cay, 110 from the exposed shelf edge- Windward Edge, and 95 from the oceanic California Bank. Larval forms dominated; copepod nauplii, fish eggs and echinoderm larvae occurred at all sites. Lucifer faxoni and Penilia avirostris were indicative of harbor waters and Microsetella sp. and Farranula carinata of offshore waters. Some zooplankton taxa, like L. faxoni, Paracalanus parvus and copepod nauplii, despite showing gradual decline with distance from Beacon to the Edge, increased in abundance at the furthest station, California. California Bank clearly experiences enrichment which at times can be as high as near-shore areas, but the planktonic community is unique and similar only to those at other offshore station. To be reliable, characterization of water masses must involve a range of physicochemical and biological parameters. Rev. Biol. Trop. 62 (Suppl. 3): 259-272. Epub 2014 September 01.

Highlights

  • There is a great deal of information concerning the planktonic communities of the Kingston Harbour and the nearby coastal shelf areas (Moore & Sander, 1979; Webber & Roff, 1996; Webber & Webber, 1998; Dunbar & Webber, 2003; Campbell, Manning, Webber & Webber, 2008)

  • All data were assessed for normal distribution using STATISTICA 7 and Log (x +1) transformations applied where necessary

  • Physicochemical parameters: Mean temperature values showed a slight decrease with increasing distance from Harbour Shoal beacon (HSB)

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Summary

Introduction

There is a great deal of information concerning the planktonic communities of the Kingston Harbour and the nearby coastal shelf areas (Moore & Sander, 1979; Webber & Roff, 1996; Webber & Webber, 1998; Dunbar & Webber, 2003; Campbell, Manning, Webber & Webber, 2008). The only previous study was conducted in 1964 and compared the zooplankton community and water quality between Kingston Harbour, the Port Royal Cays and an offshore station located 5 km away from the coastline of Jamaica (Moore & Sander, 1979). Work on water quality and plankton in Jamaica’s offshore locations has been limited to occasional cruises on large scientific vessels or to the opportunistic trips on Jamaican Coast Guard vessels These voyages provide inadequate descriptions of the offshore planktonic communities and little opportunity for contemporaneous collections in near-shore waters that would allow for adequate examination of an inshore to offshore gradient

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