Ocean temperature measured by elephant seal-CTDs in the Southern Ocean with links to datasets

The potential effects of ocean warming on marine predators are largely unknown, though the impact on the distribution of prey in vertical space may have far reaching impacts on diving predators such as southern elephant seals. We used data from satellite-tracked southern elephant seals from Marion Island to investigate the relationship between their dive characteristics (dive depths, dive durations and time-at-depth index values) and environmental variables (temperature at depth, depth of maximum temperature below 100 m, frontal zone and bathymetry) as well as other demographic and behavioural variables (migration stage, age-class, track day and vertical diel strategy). While other variables, such as bathymetry and vertical diel strategy also influenced dive depth, our results consistently indicated a significant influence of temperature at depth on dive depths. This relationship was positive for all groups of animals, indicating that seals dived to deeper depths when foraging in warmer waters. Female seals adjusted their dive depths proportionally more than males in warmer water. Dive durations were also influenced by temperature at depth, though to a lesser extent. Results from time-at-depth indices showed that both male and female seals spent less time at targeted dive depths in warmer water, and were presumably less successful foragers when diving in warmer water. Continued warming of the Southern Ocean may result in the distribution of prey for southern elephant seals shifting either poleward and/or to increasing depths. Marion Island elephant seals are expected to adapt their ranging and diving behaviour accordingly, though such changes may result in greater physiological costs associated with foraging.

Geochemistry of manganese nodules from a British Columbia fjord

Concretions of iron and manganese oxides and hydrous oxidesóobjects commonly called manganese nodulesóare widely distributed not only on the deep-sea floor but also in shallow marine environments1. Such concretions were not known to occur north of Cape Mendocino in the shallow water zones bordering the North-East Pacific Ocean until the summer of 1966 when they were recovered by one of us (J. W. M.) in dredge samples from Jervis Inlet, a fjord approximately 50 miles north-west of Vancouver, British Columbia.

Geochemistry of ODP Leg 135 vitrophyric rhyolite samples

In-situ proton-microprobe analyses are presented for glasses, plagioclases, pyroxenes, olivines, and spinels in eleven samples from Sites 834-836, 839, and 841 (vitrophyric rhyolite), plus a Tongan dacite. Elements analyzed are Mn, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Pb, and Sn (in spinels only). The data are used to calculate two sets of partition coefficients, one set based on the ratio of element in mineral/element in coexisting glass. The second set of coefficients, thought to be more robust, is corrected by application of the Rayleigh fractionation equations, which requires additional use of modal data. Data are presented for phenocryst core-rim phases and microphenocryst-groundmass phases from a few samples. Comparison with published coefficients reveals an overall consistency with those presented here, but with some notable anomalies. Examples are relatively high Zr values for pyroxenes and abnormally low Mn values in olivines and clinopyroxenes from Site 839 lavas. Some anomalies may reflect kinetic effects, but interpretation of the coefficients is complicated, especially in olivines from Sites 836 and 839, by possible crystal-liquid disequilibrium resulting from mixing processes.

Annotated record and chemical composition of manganese nodules from station VITYAZ 4575, Indian Ocean

Analyses are given for the core and outer colliform shell of a manganese nodule collected at a depth of 5000 m in the Indian Ocean, and for the red clay that encloses the nodules. Trace elements determined include rare earths, Nb, Ta, Th, and V. The cores of the nodules were once composed of basaltic rock, but now are phillipsite and nontronite. The outer shell is composed of manganite, with admixed quartz, phillipsite, and some geothite. The correlations established between the redox potentials and the concentration coefficients for 12 elements indicate that Eh plays a greater role in the formation of the manganiferous shells than coprecipitation properties.