This paper describes a comparison between balloon radio-soundings made in summer at the Concordia station, Dome C, Antarctica and coincident model-based meteorological analyses. The comparison allows the assessment of the reliability of the analyses in summer. This allows the use of the winter analyses within an estimated range of uncertainty, while the first in situ measurements are just becoming available. The astronomical interest is to produce an estimate of atmospheric turbulence during the Antarctic winter at this very promising site. For this work the 6-hourly ECMWF operational analyses were used, concurrently with the data obtained in situ by the radio-sounding made at Concordia with standard meteorological balloons and sondes during four summer seasons (November–January), from December 2000 to the end of January 2004.

The northern Victoria Land coastal marine environment was investigated during the late summer 2004, within the framework of the Latitudinal Gradient Project (LGP), to describe the physical, chemical and biological patterns of the water column and their relationship with the pelagic and benthic compartments, and to determine to what extent they change with latitude. A latitudinal gradient from Cape Adare to the Terra Nova Bay–Cape Russell area was determined on the basis of abiotic and trophic factors. Cape Adare had lower values of organic matter (particulate organic carbon < 150 μg l−1) available for the benthic communities, but this organic matter had good trophic quality. In Terra Nova Bay the particulate organic matter was quantitatively higher (organic carbon > 400 μg l−1), presumably reaching the bottom via faecal pellets, but was more detrital, although its nutritive value was still high (carbon protein content nearly 40%), as confirmed by the great quantity of phytopigments in the sediments (> 4.0 μg g−1). The benthic communities changed with latitude as well, partially reflecting the environmental and trophic gradient, but also showing a large within-area variability (except for the Cape Adare area), due to a complex array of variables that did not change with latitude.

Kohnen Station (75°S, 0°E, 2892 m) is one of the two drilling sites of the European Project for Ice Coring in Antarctica. Snow falls at Kohnen only a few times a year with comparatively high precipitation rates of 1 mm to over 5 mm water equivalent per event. These events contribute considerably to the total annual accumulation of which the long-term mean value is 62 mm water equivalent per year. For ice core interpretation, it is important to understand synoptic processes leading to such high precipitation rates. Our investigation is based on visually observed periods of heavy snowfall at Kohnen during summer campaigns since 2001/2002. The corresponding synoptic situations can be grouped into three categories. Category I is where occluding fronts of eastward-moving low pressure systems reach the plateau, a fairly frequent occurrence. Category II is where lows or secondary lows formed east of the Greenwich Meridian move to the west (retrograde movement), and frontal clouds influence the plateau. In Category III, large-scale lifting processes (due to an upper air low west of Kohnen Station) lead to cloud formation over the plateau of Dronning Maud Land.

In 2004 as part of the joint Latitudinal Gradient Project in the Ross Sea, cruises of RV Tangaroa and RV Italica along the Victoria Land coast and the Balleny Islands collected 142 species of mollusc (four Polyplacophora, 99 Gastropoda, 37 Bivalvia and two Scaphopoda). About 20% of these species represent new records for the Ross Sea quadrant. The species richness was found to be higher at 71–72°S (Cape Hallett–Cape Adare) and lower at 74–75°S (Terra Nova Bay–Cape Russell) using Shannon-Wiener's H', Pielou's J' and Simpson's λ indices, as well as by using species richness estimators (e.g. ICE, Chao 2, Jack 2). The Balleny Islands (65–67°S), though not exhaustively sampled, show diversity values comparable to those of Terra Nova Bay–Cape Russell. These islands, located in the main Antarctic Coastal Current, appear to represent a crossroads in the Southern Ocean, with mollusc and other invertebrate species present, that have previously been recorded only from the Weddell Sea. The higher diversity in the Cape Hallett–Cape Adare area is not easy to interpret, but could be a result of the intense iceberg scouring off the two capes, observed from seafloor mapping, a factor that is known to enhance species diversity at the regional scale. The existence of a decreasing trend in diversity towards higher latitudes along the Victoria Land coast cannot yet be shown, due to the large gaps in sampling coverage.

This paper is a contribution to the Latitudinal Gradient Project. It describes macro and epifaunal assemblages and habitats at three shallow water locations at the southern end of the western Ross Sea coast, and investigates relationships between faunal composition and environmental characteristics. Many variables (e.g. substrate type, sediment composition, depth, latitude, longitude) contributed to explaining the differences in community composition between locations, with latitude (a likely surrogate for broader scale factors, e.g. ice cover) one of the most important. The percentage explained by environmental characteristics was strongly scale dependent, decreasing with increasing scale of observation. As much as 66% and 75% of the variability in macrofaunal and epifaunal assemblages, respectively, was explained at the smallest scale (i.e. between transects within a location), compared to 9–18% and 11–32%, respectively, at the scale of the entire study. This relationship was also true for species richness and total abundance. This suggests that while small-scale habitat variability will not confound our ability to detect latitudinal gradients in future studies, adequately quantifying the environmental factors important in structuring these communities at larger (latitudinal) spatial scales will be important. Finally, large differences in habitat structure did not translate into large differences in the diversity of fauna, illustrating the difficulty of predicting faunal composition in the Ross Sea based on seafloor topography alone.

The endemic Antarctic scallop Adamussium colbecki (Mollusca: Bivalvia) represents a key species in the Ross Sea littoral benthic ecosystem, locally reaching very high densities. This species has an annual gametogenic cycle, with a summer spawning event, and a pelagic larval behaviour. This paper aims at describing population structure and genetic polymorphism (using AFLP) of the large populations inhabiting the Ross Sea (Terra Nova Bay and McMurdo Sound) in order to investigate possible genetic exchange between A. colbecki in these areas. In Terra Nova Bay, size-frequency distributions show, generally, the dominance of large individuals, although site related differences are found in the abundance of smaller size classes (less than 40 mm), suggesting that recruitment is not a regular event. All McMurdo sites are characterized by large individuals and, at least during this sampling period, recruitment is completely absent. Nuclear DNA analyses show that the largest differences are found at the largest scale (between McMurdo Sound and Terra Nova Bay), but all populations sampled, even at a smaller spatial scale, have a well-settled genetic structure, notwithstanding the pelagic larval strategy. The panmixia hypothesis has therefore to be rejected for this species.

Data from two new cruises is used to assess whether latitude plays any role in influencing broad-scale spatial patterns in echinoderm assemblage composition along the Victoria Land coast and the Balleny Islands as a contribution to the Latitudinal Gradient Project. Our results indicate that a latitudinal gradient is influencing assemblage structure in subtle and non-linear ways. The Balleny Islands system is different from the Victoria Land coast, probably because of a different biogeographic origin and current oceanographic conditions. Along the Victoria Land coast, latitude related differences arise when taking into account benthic biodiversity at different spatial scales. Alpha diversity increases from north to south, but beta diversity shows the opposite trend, although not linearly, suggesting the different importance of the iceberg disturbance along the northern Victoria Land coast.