Influence of New Zealand cockles ( Austrovenus stutchburyi ) on primary productivity in sandflat-seagrass ( Zostera muelleri ) ecotones

2016 ◽  
Vol 181 ◽  
pp. 238-248 ◽  
Author(s):  
Andrew M. Lohrer ◽  
Michael Townsend ◽  
Sarah F. Hailes ◽  
Iván F. Rodil ◽  
Katie Cartner ◽  
...  
Parasitology ◽  
2006 ◽  
Vol 134 (2) ◽  
pp. 247-255 ◽  
Author(s):  
T. L. F. LEUNG ◽  
R. POULIN

The patterns of association between parasites within a particular host are determined by a number of factors. One of these factors is whether or not infection by one parasite influences the probability of acquiring other parasite species. This study investigates the pattern of association between various parasites of the New Zealand cockleAustrovenus stutchburyi. Hundreds of cockles were collected from one locality within Otago Harbour, New Zealand and examined for trematode metacercariae and other symbionts. Two interspecific associations emerged from the study. First, the presence of the myicolid copepodPseudomyicola spinosuswas positively associated with higher infection intensity by echinostomes. The side-effect of the copepod's activities within the cockle is suggested as the proximate mechanism that facilitates infection by echinostome cercariae, leading to a greater rate of accumulation of metacercariae in cockles harbouring the copepod. Second, a positive association was also found between infection intensity of the metacercariae of foot-encysting echinostomes and that of gymnophallid metacercariae. This supports earlier findings and suggests that the gymnophallid is a hitch-hiker parasite because, in addition to the pattern of positive association, it (a) shares the same transmission route as the echinostomes, and (b) unlike the echinostomes, it is not capable of increasing the host's susceptibility to avian predation. Thus, both active hitch-hiking and incidental facilitation lead to non-random infection patterns in this parasite community.


Radiocarbon ◽  
1999 ◽  
Vol 41 (2) ◽  
pp. 119-126 ◽  
Author(s):  
Nancy Beavan Athfield ◽  
Bruce McFadgen ◽  
Rodger Sparks

A suite of 6 bone gelatin accelerator mass spectrometry (AMS) radiocarbon dates for Rattus exulans Peale and associated beta decay 14C dates for Austrovenus stutchburyi shell are presented for 4 middens at Pauatahanui, Wellington, New Zealand. Mean calibrated age ranges of Rattus exulans (520–435 BP and 350–330 BP at 95% confidence level) and shell (465–375 BP at 95% confidence level) from the 4 midden sites overlap. The agreement between Rattus exulans bone gelatin dates and associated shell provides an inter-sample comparison of 14C dating using both gas counting (beta decay) and AMS dating techniques. We examine the adequacy of the standard gelatinization treatment for bone samples, which has been employed consistently at the laboratory since 1995.


2007 ◽  
Vol 26 (1) ◽  
pp. 89-100 ◽  
Author(s):  
VONDA. CUMMINGS ◽  
JUDI. HEWITT ◽  
JANE. HALLIDAY ◽  
GRAEME. MACKAY

2021 ◽  
Author(s):  
◽  
Jessica J. Orsman

<p>Li, B, Mg, Al, Mn, Cu, Zn, As, Sr, Ba and U/Ca ratios were measured by laser ablation inductively coupled plasma mass spectrometry for 11 modern Austrovenus stutchburyi clams to assess the potential of this molluscan species as a proxy for paleo-ocean temperature and environmental change. A. stutchburyi is an intertidal, infaunal, bivalve, widespread in New Zealand coastal regions and throughout the Quaternary-Pliocene sedimentary rock record. Five individuals from Ligar Bay and Estuary (South Island, New Zealand) were analysed to evaluate the variability between individuals calcifying in similar environmental conditions. A further six individuals were sampled from a range of latitudes (38˚ to 40˚) in the North Island, New Zealand to evaluate variability between individuals from different environments. A strong positive correlation between growth rate and Mg, Al, Mn, Sr, Ba and U/Ca ratios was observed, and a marked negative correlation was found between the same trace element/Ca ratios and ontogenetic age as growth rates slow during the molluscs' life. Thus, biological effects are the primary influence on trace element incorporation in A. stutchburyi. No clear seasonal variations were observed in the Mg and Sr/Ca ratio profiles through A. stutchburyi shells representing time periods of several years. Furthermore, for two shells for which chronologies could be reliably constructed, there were no significant correlations between Mg and Sr/Ca ratios and sea surface temperature. When Mg/Ca ratios were normalised to Sr/Ca ratios in order to eliminate the growth rate effect on trace element incorporation into the mollusc shells, some of the remaining variations appeared to visually correlate positively with sea surface temperature in several sections of a shell. However, a quantitative correlation did not confirm this (r² = 0.012). It is likely that neither Mg nor Sr incorporation into A. stutchburyi shell are primarily thermodynamically controlled. Several coincident Ba/Ca peaks in two of the Ligar Bay shells are most likely caused by environmental processes such as short periods of phytoplankton blooms or elevated seawater Ba/Ca from river flooding. Mn/Ca and U/Ca variations in A. stutchburyi from different coastal sites with different sediment characteristics appeared to be linked to the redox conditions prevailing at an open ocean sand-dominated environment (Ligar Bay) versus tidal mud flat environments (e.g. Miranda). Thus, while A. stutchburyi is unlikely to be a useful archive for past coastal ocean temperatures, it holds considerable promise for tracking past changes in coastal ocean productivity and river run-off, as well as sediment redox conditions.</p>


1995 ◽  
Vol 36 (5) ◽  
pp. 725-728 ◽  
Author(s):  
Hitoshi Ishida ◽  
Akira Nozawa ◽  
Kazuhiro Totoribe ◽  
Norio Muramatsu ◽  
Haruo Nukaya ◽  
...  

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