OCCURRENCE OF KINORHYNCHS AND TINTINNIDS FROM DISENCHANTMENT BAY AND YAKUTAT BAY, ALASKA: INDICATORS FOR SEASONAL VARIABILITY AND ENVIRONMENTAL MONITORING OF FJORD SETTINGS

Multicores collected in Disenchantment Bay (DB) and Yakutat Bay (YB), Alaska during June 2004 aboard the R/V Alpha Helix contain glacial marine diamictons and laminated muds, silts and sands. Sediment samples, taken every 1 cm, were initially processed and examined for foraminifera (>63 µm fraction). Ullrich and others (2009) documented the foraminiferal distributions in these cores and recognized inter-annual variability related to vertical migration within the sediment. They interpret the sediments as couplets representing winter (diamicton) and summer (laminated muds, silts). In addition to foraminifera, these samples contain kinorhynchs (benthic, marine meiofauna) and tintinnids (pelagic ciliates), both of which are documented here.

In core AHY04MC1#2 Echinoderes, a genus in the phylum Kinorhyncha, was found from the surface down to 4 cm and at 11 cm in AHY04MC2#6, while tintinnids were found down to 20 cm in both cores. In AHY04MC6#4, tintinnids occurred at 6-8 cm and kinorhynchs were found at 7 cm. Lastly, in AHY04MC8#6, kinorhynchs and tintinnids were only found in the top 1 cm.

The distribution of kinorhynchs and tinitinnids, which ingest phytoplankton, may be a function of particulate matter, delivered to the fjords by meltwater discharge. Cores AHY04MC1#2 and AHY04MC2#6 (DB) are proximal to Hubbard Glacier and the deep downcore occurrence of tintinnids may be due to abundant particulate matter (Scott et al., 2001) and rapid burial. Core AHY04MC8#6 (YB) is more distal and restriction of tintinnids and kinorhynchs to the sediment surface may be due to less particulate matter, lower accumulation rates, winnowed substrates, and proximity to the open Gulf of Alaska. Echols and Fowler (1979) show that some tintinnids can indicate fresh water plumes, but may also be easily transported due to their small size and buoyancy. Abundant tintinnids and benthic foraminifera (dominated by Elphidium spp. and Textularia earlandi) in DB suggest low salinity surface and normal salinity bottom waters whereas tintinnids in the YB core may have been transported.

Samples were not taken to study kinorhynchs and tinitinnids, but their occurrence provides additional insight. Future studies aimed at monitoring the climatic and paleoenvironmental record of fjords should include these organisms.