Seasonal changes in structure of an Alaskan intertidal meiofaunal assemblage

Abstract

ABSTRACT. A subarctic, intertidal meiofaunal assemblage in Auke Bay, Alaska, USA, was sampled throughout one year a t 3 intertidal heights; mean low water (0 m) and 1 m above and below this level ( + l m, -1 m). Samples were taken twice a month at 0 m and approximately every other month at -1 and + l m intertidal heights. Nematodes predominated numerically (31 to 77'?0), followed by harpacticoid copepods (adults and copepodites combined 10 to 35%, nauplii 5 to 32%). Meiofaunal densities fluctuated significantly throughout the sampling period. The demography of the 6 numerically predominant species of copepods was examined. In order of abundance, they were Halectinosoma sp., Amphiascoides dirnorphus Lang 1965, Microarthridion cf. littorale Poppe 1881, Apolethon sp., Mesochra sp. and Stenhelia (Stenhelia) pen~culata Lang 1965. Densities of the adults, ovigerous females and copepodites of these species changed significantly throughout time. The peak densities of ovigerous females and copepodites were well separated temporally (whereas those of adults overlapped) and tended to occur in months from November to March. Only M. cf. littorale displayed a high abundance of ovigerous females and copepodites in the summer months. Reproductive patterns vaned among the harpacticoid species, from discrete (Apolethon sp.) to continuous reproductive periodicity (all other species).

Crustacea in Arctic and Antarctic Sea Ice: Distribution, Diet and Life History Strategies

“…Furthermore, the occurrence of high densities of harpacticoid nauplii in ice from the Arctic Ocean (Gradinger, 1999) and BaYn Bay (Nozais et al, 2001) indicates that reproduction is continually performed in the ice environment. Continual reproduction has been observed for harpacticoid copepods both in sub-Arctic waters (Schizas and Shirley, 1996) and at lower latitudes (Hall and Bell, 1993;Steinarsdo ´ttir et al, 2003).…”

“…Ovigerous females and copepodid stages of Harpacticus sp. were present all year round in the intertidal benthos near Auke Bay (southeast coast of Alaska), although densities peaked between November and March (Schizas and Shirley, 1996). Given the strong seasonal signal in Arctic waters, it is likely that spawning of Harpacticus sp.…”

A seasonally varying biotope at Signy Island, Antarctic: implications for meiofaunal structure

“…nematodes and copepods) are comparatively scarce, and are limited to estuarine (Eskin & Coull 1987, Ansari & Parulekar 1993, intertidal (Alongi 1987, Bouvy & Soyer 1989, Schizas & Shirley 1996, or temperate subtidal (Juario 1975, Boucher 1980, 1983, Rudnick et al 1985, Vincx 1989, Ólafsson & Elmgren 1997, Steyaert et al 1999 regions.…”

Seasonal variability of meiobenthic assemblages inhabiting the Nottinghambukta tidal flat, SW Spitsbergen

“…Meiobenthos (meiofauna) as a functional complex group of organisms is subject to further divisions, among others, to marine and freshwater units, as well as permanent (specimens belonging to a given group throughout their life cycle) and temporary components (juvenile stages of macrobenthos). According to some authors (Soltwedel 1997;Gal'tsova et al 2004;Radziejewska et al 2006;Brandt et al 2007;Giere 2009), Metazoa and large Protista and Foraminifera in particular, are regarded as meiobenthos, while others restrict marine meiobenthos to Metazoa (Sommerfield and Warwick 1996;Schizas and Shirley 1996).…”