Russell R. Hopcroft

Annual abundance and biomass of aloricate ciliates in tropical neritic waters off Kingston, Jamaica

The daily abundance of aloricate ciliates at Lime Cay, Jamaica, a shallow neritic site, ranged from 29 to 118 × 106 m−2 (0.97 to 3.93 × 106 m−3) between November 1985 and November 1986. Biomass was converted to kilojoules (1 kcal=4.1855 kJ) assuming 42% carbon, 20.15 kJ (g dry wt)−1, and 20% cell shrinkage. Biomass ranged from 0.40 to 3.00 kJ m−2 (13.3 to 100 J m−3; 0.28 to 2.08µg C l−1) with an annual mean of 1.11 kJ m−2 (36.8 J m−3; 0.764µg C l−1). Nanociliates (<20µm equivalent spherical diameter, ESD) dominated abundance, but microciliates (> 20µm ESD) dominated biomass.Strombidium, Strobilidium, Tontonia andLaboea species were conspicuous taxa. Annual production estimates of the aloricate assemblage, based on literature growth rates, ranged from 404 kJ m−2 yr−1 (37 J m−3 d−1) to 1614 kJ m−2 yr−1 (147 J m−3 d−1). A compromise estimate of 689 kJ m−2 yr−1 (i.e., 63 J m−3 d−1) is comparable to other estimates from tropical and subtropical regions. A model of annual energy flow through 11 planktonic compartments suggests the total ciliate assemblage (aloricates and tintinnines) to be as productive as metazoan herbivores and metazoan carnivores.

Size-fractionated sedimentation in a tropical neritic ecosystem near Kingston, Jamaica

Abstract Particles collected at a tropical neritic station by 24 h sediment trap deployment were size fractionated and analysed for chlorophyll a and phaeopigment. Under calm conditions, picoparticles ( 30% of the netplankton (>20μm) daily primary production were exported to the benthos. Assuming that the annual pattern of net sedimentation can be predicted from a knowledge of the size structure and production of the phytoplankton, our calculations indicate a flux to the benthos of 36 g Cm−2 y−1 or ∼15% of the annual primary production.