Changes in the sea-ice brine community during the spring-summer transition, McMurdo Sound, Antarctica. I. Photosynthetic protists

Abstract

Dunng the austral spring, a characteristic microbial community develops in the subsurface brine pockets and channels of the annual land-fast sea-lce in Mch4urdo Sound. This community IS distinct from the d~atom-dominated commun~ty that develops in the channels at the base of the scaice, at the seawater/icc interface, and In the platelet layer The photosynthetic biomass In the brlne pockets is domlnated by athecate dinoflagellates Chrysophyte statocysts (sometimes known as archaeomonads) and <5 l m photosynthetic flagellates are also charactel-~stlcally found in thls assemblage. In December, chlorophyll a content and blornass peak, and photosynthetic gymnodinloid dinoflagellates can reach densities of over 10' ml-' of brine The photosynthetic d~noflagellates form cysts (hypnozygotes) during late December and early January, and chrysophyte statocysts also become abundant DUI-lng austral summer, total autotroph~c biomass In the upper Ice brine decreases d u e to dilutlon by melt water, flushlng of brine Into the water column, and grazlng. By late summer, the annual sea-ice in McMurdo Sound has broken out. The yearly decay and retreat of sed-ice introduces a characteristic set of brlne protists and thelr cysts into Mcblurdo Sound.

Planktonic ciliates in the oligotrophic Mediterranean Sea: longitudinal trends of standing stocks, distributions and analysis of food vacuole contents

“…According to Stoecker et al (1992), the factors used to convert biovolumes to biomass are influenced by taxon as well as the fixation method. During this study, the conversion factor 0.14 pg C µm -3 was used, as has been suggested for ciliates fixed with 2% formaldehyde (Putt & Stoecker 1989).…”

Planktonic ciliates in the oligotrophic Eastern Mediterranean:vertical, spatial distribution and mixotrophy

“…According to Stoecker et al (1992), the factors used to convert biovolumes to biomass are influenced by taxon as well as fixation method. During this study, the conversion factor 0.14 pg C pm-3 was used, as has been suggested for cihates fixed with 2 % formaldehyde (Putt & Stoecker 1989, Lessard 1991.…”

Ingestion of bacterial cells by the marine photosynthetic ciliate Myrionecta rubra

“…As a functional primary producer, M. rubra is very common and often causes recurrent red tides in diverse marine pelagic environments, including fjords (Taylor et al 1971, Lindholm 1985, polar water under ice, and in deep water of the adjacent seas (Putt 1990, Satoh & Watanabe 1991, Stoecker et al 1992, Perriss et al 1995. M. rubra has been considered as an unculturable species (Lindholm 1985) ever since Charles Darwin described it as 'minute animalcula darting about, and often exploding' (Darwin 1845, Taylor et al 1971, until recently when isolates were grown as laboratory cultures by 2 research groups (Gustafson et al 2000, Kim 2002).…”