Micronekton and Macrozooplankton of the Western Antarctic Peninsula and the Eastern Ross Sea: Contrast Between Two Different Thermal Regimes

• Main Author: Parker, Melanie Leigh
• Format: Doctoral or Postdoctoral Thesis
• Language: unknown
• Published: Digital Commons @ University of South Florida 2012
• Subjects: Assemblage; Continental Shelf; Distribution; Fishes; Krill; American Studies; Arts and Humanities; Other Oceanography and Atmospheric Sciences and Meteorology; Antarctic; Antarctic Peninsula; Austral; Charcot; Charcot Island; Joinville; Joinville Island; Marguerite; Marguerite Bay; Ross Sea; Southern Ocean; Antarc*
• Online Access: https://digitalcommons.usf.edu/etd/4196; https://digitalcommons.usf.edu/context/etd/article/5392/viewcontent/Parker_usf_0206D_11211.pdf

ABSTRACT Micronekton and macrozooplankton were sampled from the Western Antarctic Peninsula (WAP) and eastern Ross Sea regions. Samples were collected over the course of six research cruises to the Southern Ocean. Four of those cruises were conducted in the Marguerite Bay region of the WAP during the austral fall and winter of 2001 and 2002. A fifth cruise sampled faunal assemblages at nine sites, ranging from Joinville Island at the northern tip of the WAP to Charcot Island near the southern extent of the WAP, during austral fall 2010. A sixth cruise was conducted in the pack ice within the offshore, continental slope, and continental shelf zones of the Eastern Ross Sea during austral summer 1999/2000. The purpose of this dissertation was to describe the macrozooplanktonic/ micronektonic faunal assemblages present in each of those regions and relate differences in species composition and distribution patterns to local bathymetry, hydrography, and physical conditions. A variety of multivariate techniques were used to identify unique multispecies assemblages and to quantify the contributions of both oceanic and neritic species to the assemblages within each study region. The invertebrate micronekton/macrozooplankton communities found in the Marguerite Bay region of the WAP during the 2001/2002 cruises were a mixture of oceanic and neritic fauna: a direct result of local hydrographic conditions. Near the shelf break and in the outer reaches of the Marguerite Trough, a deep canyon transecting the shelf in a south-southeast direction, the communities were more diverse, dominated by oceanic species such as the euphausiid, Euphausia triacantha, the salp, Salpa thompsoni, and, an amphipod, Themisto gaudichaudii. The assemblages present in the nearshore fjords exhibited lower diversity and were dominated by neritic species such as the euphausiid, E. crystallorophias, and the mysid, Antarctomysis ohlinii. At the mid-shelf and mid-trough locations, the assemblages were composed of a variable mixture of oceanic and neritic ...