Southern Hemisphere Regions Research Articles

Spatio-temporal variation of biomass burning sources over South and Southeast Asia

In this study, we have investigated the seasonality and long-term trends of major biomass burning (BB) sources over South and Southeast Asia (S-SE Asia). The activities of BB and related emissions show bi-modal seasonality in S-SE Asia. From January to May period, the BB dominates in the northern hemisphere parts of S-SE Asia. From July to September, the activities shift to the southern hemisphere where the emissions from Indonesian and Malaysian islands make largest contributions. Overall, the activities of BB are lowest during October–December period in S-SE Asia. The seasonality of BB intensity and rain are just opposite in the phase over India. The climatological (1997–2008) emissions of carbon monoxide (CO), oxides of nitrogen (NOx) and non-methane hydrocarbons (NMHCs) show strong spatio-temporal variation. The trends show large inter-annual variations with highest and lowest values during years 1997 and 2000, respectively. In the southern hemisphere parts of S-SE Asia mainly in Indonesia, the intensity of biomass fires has been modulated by the large scale climatic phenomena like El Nino and Southern Oscillation (ENSO). The annual emissions of trace gases in southern hemisphere region during the El Nino years exceed to those for the normal years. The estimates for northern hemisphere region during the La Nina years were significantly higher than those for the normal years. The Model for Ozone And Related Chemical Tracers (MOZART) simulations of columnar CO and NOx tend to capture the prominent features of BB emissions in S-SE Asia. The impacts of extensive fires in Indonesia during El Nino year of 2006 compared to a normal year of 2005 were clearly seen in the MOZART-4 simulations of both CO and NOx.

Global climate analogues for winegrowing regions in future periods: projections of temperature and precipitation

Background and Aims Climate is a key consideration for winegrowers, so information regarding projected climate change and the relative global impacts are of great interest. Methods and Results This climate analogue approach compares and contrasts future to current climate among the regions. Warming was projected for all regions, with greater warming in Northern Hemisphere continental regions and less for Southern Hemisphere and coastal regions. Projections of annual precipitation varied, with the median result from the range of models indicating a wetter climate for higher latitude regions, such as New Zealand, Mosel Valley and North Oregon, and the Chinese region in this study, while Southern European, Australian and South African winegrowing regions had a projected drier climate. The median model result for winter precipitation indicated a projected decrease for sites in Chile, Greece, Australia and Spain, with other European and American sites experiencing a slight increase in winter precipitation. Shandong, China, was the only region in this study projected to experience increased summer precipitation. Conclusion Future temperature and precipitation projections were made for 23 winegrowing regions worldwide and compared using a climate analogue approach. Significance of the Study An estimated future temperature and precipitation climatology centred on 2030 and 2070 for 23 winegrowing regions worldwide is made using results from 23 global climate models. Using these climatologies, along with consideration of length of the planning horizon, legal limitations and inter-regional climate variability, climate analogues can be described. For future planning, winegrape cultivars better suited to the projected climate may then be selected from the range currently growing in identified analogue regions. Alternatively, climatically optimum sites can be identified for growing particular cultivars in future conditions.

Continental-scale temperature variability during the past two millennia

Past global climate changes had strong regional expression. To elucidate their spatio-temporal pattern, we reconstructed past temperatures for seven continental-scale regions during the past one to two millennia. The most coherent feature in nearly all of the regional temperature reconstructions is a long-term cooling trend, which ended late in the nineteenth century. At multi-decadal to centennial scales, temperature variability shows distinctly different regional patterns, with more similarity within each hemisphere than between them. There were no globally synchronous multi-decadal warm or cold intervals that define a worldwide Medieval Warm Period or Little Ice Age, but all reconstructions show generally cold conditions between ad 1580 and 1880, punctuated in some regions by warm decades during the eighteenth century. The transition to these colder conditions occurred earlier in the Arctic, Europe and Asia than in North America or the Southern Hemisphere regions. Recent warming reversed the long-term cooling; during the period ad 1971–2000, the area-weighted average reconstructed temperature was higher than any other time in nearly 1,400 years.

Global genetic population structure in the commercially exploited deep-sea teleost orange roughy (Hoplostethus atlanticus) based on microsatellite DNA analyses

The widely distributed teleost orange roughy, Hoplostethus atlanticus, has been one of the main species targeted in deep-sea fisheries. While morphometric, parasite and otolith analyses have generally found differentiation among populations within ocean basins, genetic techniques have shown contradictory results at different geographical scales. Here, we used nine microsatellite DNA loci to study genetic diversity and differentiation in orange roughy at a global scale using samples from New Zealand, Australia, Namibia, Chile, and the Northeast Atlantic Ocean. Additionally, temporal genetic variation was assessed for eight sites in Northern New Zealand sampled in two different years. The expected heterozygosity was high in all the sites, suggesting high levels of genetic diversity in orange roughy. Overall, we detected low but significant differentiation at the global scale: across the Southern hemisphere and between the Southern hemisphere regions and the Northeast Atlantic Ocean. However, genetic homogeneity was found between New Zealand and Australia. The present data does not showed temporal variation in orange roughy from Northern New Zealand. A pattern of isolation by distance at the global scale suggests stepping-stone migration, which is likely the result of active adult dispersal. This study revealed levels of genetic differentiation at the global scale that were undetected with mitochondrial DNA sequences analyses.

Temporal introduction patterns of invasive alien plant species to Australia

We examined temporal introduction patterns of 132 invasive alien plant species (IAPS) to Australia since European colonisation in 1770. Introductions of IAPS were high during 1810-1820 (10 species), 1840- 1880 (51 species, 38 of these between 1840 and 1860) and 1930-1940 (9 species). Conspicuously few introductions occurred during 10-year periods directly preceding each introduction peak. Peaks during early European settlement (1810-1820) and human range expansion across the continent (1840-1860) both coincided with considerable growth in Australia's human population. We suggest that population growth during these times increased the likelihood of introduced plant species becoming invasive as a result of increased colonization and propagule pressure. Deliberate introductions of IAPS (104 species) far outnumbered accidental introductions (28 species) and were particularly prominent during early settlement. Cosmopolitan IAPS (25 species) and those native solely to South America (53 species), Africa (27 species) and Asia (19 species) have been introduced deliberately and accidentally to Australia across a broad period of time. A small number of IAPS, native solely to Europe (5 species) and North America (2 species), were all introduced to Australia prior to 1880. These contrasting findings for native range suggest some role for habitat matching, with similar environmental conditions in Australia potentially driving the proliferation of IAPS native to southern-hemisphere regions. Shrub, tree and vine species dominated IAPS introduced prior to 1840, with no grasses or forbs introduced during early colonisation. Since 1840, all five growth forms have been introduced deliberately and accidentally in relatively large numbers across a broad period of time. In particular, a large number of grass and forb IAPS were deliberately introduced between 1840 and 1860, most likely a direct result of the introduction of legislation promoting intensive agriculture across large areas of the continent. Since the 1980s, only three IAPS have been introduced (all deliberately introduced forbs). The decline in IAPS introductions is most likely a reflection of both increased surveillance and biosecurity efforts and the likelihood that many potential IAPS are still within a pre-expansion lag period.

Wegener's granulomatosis: treatment and survival characteristics in a high‐prevalence southern hemisphere region

Our aim was to describe the treatment and survival characteristics of Wegener's granulomatosis (WG) in Canterbury, New Zealand. The medical records of 48 patients diagnosed between 1 July 1997 and 31 December 2008 and fulfilling validated classification criteria for WG were reviewed to characterise survivorship in the province of Canterbury, New Zealand. The age at diagnosis was 61 years (range 20 to 83 years) with an equal number of males and females. Using Kaplan-Meier product-limit analysis, the probability of survival at 1 and 10 years was 91% and 62% respectively. Of the 12 deaths in the cohort, four occurred within 12 months of diagnosis: two from pulmonary haemorrhage and two from renal failure. Beyond 12 months, two patients died of renal failure, two of myocardial infarction and one from cardiac arrhythmia, one from cerebrovascular disease and two from colorectal carcinoma. The median time to relapse was 6.75 years, and the probability of relapse within 10 years was 67%. Survivorship, treatment response rate and the rate of relapse from WG in a cohort of patients from this high-prevalence southern hemisphere region were similar to that reported for northern hemisphere cohorts with a similar prevalence.

The Potential Utility of Adjuvanted Seasonal Influenza Vaccine for Travelers

The recently published report and commentary on the risks of acquiring influenza during travel highlights the particular difficulty of protecting persons traveling from the northern to the southern hemisphere and vice versa. 1,2 The frequency of infections acquired in these circumstances was clearly documented by the experience of Mutsch and colleagues at the University of Zurich (northern hemisphere), where influenza cases were encountered throughout the year, comprising infections acquired in the southern hemisphere and equatorial regions where influenza may be transmitted year‐round. 3–5 The approach of importing vaccines from the alternate hemisphere to address the needs of such travelers might be feasible in some countries under a compassionate use authorization, but it would be unrealistic to believe that manufacturers could license alternate hemisphere formulations for such limited use. The US Centers for Disease Control (CDC) and others have thus recommended northern hemisphere formulation vaccines for persons traveling to the southern hemisphere but the short shelf‐life and uniform expiration of northern hemisphere vaccines in June is an important limitation. This is especially true for the large numbers of travelers departing in July and August, during the typical northern hemisphere holiday season when … Corresponding Author: Theodore F. Tsai, MD, MPH, FIDSA, Novartis Vaccines, 350 Mass Ave, Cambridge, MA 02139, USA. E‐mail: theodore.tsai{at}novartis.com

Genetic diversity of Southern hemisphere blue mussels (Bivalvia: Mytilidae) and the identification of non-indigenous taxa

The taxonomic and evolutionary affinities of Southern hemisphere smooth-shelled blue mussels are unclear, with studies using different marker types having identified different relationships among various geographic regions. Using an existing and a new molecular assay, the present study builds on previous work to test the distribution of blue mussels native to and introduced to the Southern hemisphere. Populations of Mytilus were sampled from New Zealand, Australia, and Chile. The nuclear-DNA marker Me 15/16 was used to identify the taxonomic status of 484 individuals. A new restriction fragment length polymorphism (RFLP) assay was used to identify the hemisphere of origin for a subset of Mytilus galloprovincialis. The Me15/16 marker identified 478 pure M. galloprovincialis from Southern hemisphere sites and six Mytilus edulis/M. galloprovincialis hybrids from the Auckland Islands (New Zealand) and Chile. A cytoplasmic RFLP identified Northern hemisphere M. galloprovincialis in almost every Southern hemisphere region. The presence of native M. galloprovincialis at high latitudes (up to 52°S) has implications for our understanding of environmentally induced selective constraints considered to determine species distributions. Widespread occurrence of invasive Northern hemisphere blue mussels in the Southern hemisphere is documented for the first time. Identification of inter-specific hybrids (M. edulis ¥ M. galloprovincialis) in Chile and in the Auckland Islands (subantarctic New Zealand) illustrates that environments ranging from international ports to remote protected locations are vulnerable to bioinvasion. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 898‐909.

Spread and impact of introduced conifers in South America: Lessons from other southern hemisphere regions

AbstractThe history of conifers introduced earlier elsewhere in the southern hemisphere suggests that recent invasions in Argentina, Brazil, Chile and Uruguay are likely to increase in number and size. In South Africa, New Zealand and Australia, early ornamental introductions and small forestry plantations did not lead to large‐scale invasions, while subsequent large plantations were followed with a lag of about 20–30 years by troublesome invasions. Large‐scale conifer plantation forestry in South America began about 50–80 years later than in South Africa, Australia and New Zealand, while reports of invasions in South America lagged behind those in the latter nations by a century. Impacts of invading non‐native conifers outside South America are varied and include replacement of grassland and shrubland by conifer forest, alteration of fire and hydrological regimes, modification of soil nutrients, and changes in aboveground and belowground biotic communities. Several of these effects have already been detected in various parts of South America undergoing conifer invasion. The sheer amount of area planted in conifers is already very large in Chile and growing rapidly in Argentina and Brazil. This mass of reproductive trees, in turn, produces an enormous propagule pressure that may accelerate ongoing invasions and spark new ones at an increasing rate. Regulations to control conifer invasions, including measures to mitigate spread, were belatedly implemented in New Zealand and South Africa, as well as in certain Australian states, inspired by observations on invasions in those nations. Regulations in South America are weaker and piecemeal, but the existing research base on conifer invasions elsewhere could be useful in fashioning effective regulations in South America. Pressure from foreign customers in South Africa has led most companies there to seek certification through the Forestry Stewardship Council; a similar programme operates in Australia. Such an approach may be promising in South America.

Effect of regional precursor emission controls on long-range ozone transport – Part 2: Steady-state changes in ozone air quality and impacts on human mortality

Abstract. Large-scale changes in ozone precursor emissions affect ozone directly in the short term, and also affect methane, which in turn causes long-term changes in ozone that affect surface ozone air quality. Here we assess the effects of changes in ozone precursor emissions on the long-term change in surface ozone via methane, as a function of the emission region, by modeling 10% reductions in anthropogenic nitrogen oxide (NOx) emissions from each of nine world regions. Reductions in NOx emissions from all world regions increase methane and long-term surface ozone. While this long-term increase is small compared to the intra-regional short-term ozone decrease, it is comparable to or larger than the short-term inter-continental ozone decrease for some source-receptor pairs. The increase in methane and long-term surface ozone per ton of NOx reduced is greatest in tropical and Southern Hemisphere regions, exceeding that from temperate Northern Hemisphere regions by roughly a factor of ten. We also assess changes in premature ozone-related human mortality associated with regional precursor reductions and long-range transport, showing that for 10% regional NOx reductions, the strongest inter-regional influence is for emissions from Europe affecting mortalities in Africa. Reductions of NOx in North America, Europe, the Former Soviet Union, and Australia are shown to reduce more mortalities outside of the source regions than within. Among world regions, NOx reductions in India cause the greatest number of avoided mortalities per ton, mainly in India itself. Finally, by increasing global methane, NOx reductions in one hemisphere tend to cause long-term increases in ozone concentration and mortalities in the opposite hemisphere. Reducing emissions of methane, and to a lesser extent carbon monoxide and non-methane volatile organic compounds, alongside NOx reductions would avoid this disbenefit.

Global diversity of large branchiopods (Crustacea: Branchiopoda) in freshwater

With about 500 known species worldwide, the large brachiopods are a relatively small group of primitive crustaceans. With few exceptions they live in temporary aquatic systems that are most abundant in arid and semi arid areas. As many regions remain unexplored and as especially the number of species in clam shrimps and tadpole shrimps is underestimated due to difficult identification, the species list will increase with future surveys. The Branchiopoda are monophyletic, but inter-ordinal relationships, as well as many evolutionary relationships at lower taxonomic levels are still unclear. Ongoing molecular studies will more accurately depict species diversity and phylogenetic patterns. With the exception of some anostracan families, most families are not restricted to the northern or southern hemisphere or specific zoogeographical regions. Large branchiopods are used for the assessment of the quality and function of temporary wetlands. Due to the reduction in number and quality of temporary wetlands, several species became endangered and are red listed by the IUCN.

Inter-hemispheric linkages in climate change: paleo-perspectives for future climate change

Abstract. The Pole-Equator-Pole (PEP) projects of the PANASH (Paleoclimates of the Northern and Southern Hemisphere) programme have significantly advanced our understanding of past climate change on a global basis and helped to integrate paleo-science across regions and research disciplines. PANASH science allows us to constrain predictions for future climate change and to contribute to the management of consequent environmental changes. We identify three broad areas where PEP science makes key contributions. 1. The pattern of global changes. Knowing the exact timing of glacial advances (synchronous or otherwise) during the last glaciation is critical to understanding inter-hemispheric links in climate. Work in PEPI demonstrated that the tropical Andes in South America were deglaciated earlier than the Northern Hemisphere (NH) and that an extended warming began there ca. 21 000 cal years BP. The general pattern is consistent with Antarctica and has now been replicated from studies in Southern Hemisphere (SH) regions of the PEPII transect. That significant deglaciation of SH alpine systems and Antarctica led deglaciation of NH ice sheets may reflect either i) faster response times in alpine systems and Antarctica, ii) regional moisture patterns that influenced glacier mass balance, or iii) a SH temperature forcing that led changes in the NH. This highlights the limitations of current understanding and the need for further fundamental paleoclimate research. 2. Changes in modes of operation of oscillatory climate systems. Work across all the PEP transects has led to the recognition that the El Niño Southern Oscillation (ENSO) phenomenon has changed markedly through time. It now appears that ENSO operated during the last glacial termination and during the early Holocene, but that precipitation teleconnections even within the Pacific Basin were turned down, or off. In the modern ENSO phenomenon both inter-annual and seven year periodicities are present, with the inter-annual signal dominant. Paleo-data demonstrate that the relative importance of the two periodicities changes through time, with longer periodicities dominant in the early Holocene. 3. The recognition of climate modulation of oscillatory systems by climate events. We examine the relationship of ENSO to a SH climate event, the Antarctic cold reversal (ACR), in the New Zealand region. We demonstrate that the onset of the ACR was associated with the apparent switching on of an ENSO signal in New Zealand. We infer that this related to enhanced zonal SW winds with the amplification of the pressure fields allowing an existing but weak ENSO signal to manifest itself. Teleconnections of this nature would be difficult to predict for future abrupt change as boundary conditions cannot readily be specified. Paleo-data are critical to predicting the teleconnections of future changes.

Quaternary paleoecology of aquatic Diptera in tropical and Southern Hemisphere regions, with special reference to the Chironomidae

Chironomid paleoecology in north-temperate regions has made tremendous progress over the past decade, but studies in tropical and Southern Hemisphere regions remain relatively scarce. Reasons for this imbalance are (1) incomplete taxonomic knowledge of chironomid faunas outside Europe and North America, (2) a scarcity of ecological data on local species and genera that might confer bio-indicator value to them, and (3) logistic difficulties hampering the lake surveying necessary to develop paleoenvironmental calibration data sets. Thus far, most chironomid paleoecology in tropical and Southern Hemisphere regions has relied on an indicator-species approach, combining autecological information on local species of which larval morphology is known with the traditional ecological typology of chironomid genera transferred from the Holarctic region. This paper reviews work accomplished to date in tropical and temperate South America, Australia, Africa, and New Zealand, including studies on various families of non-chironomid Diptera with diagnostic fossils. Research has focused mostly on late-Glacial and Holocene climate reconstruction, less on tracing past human disturbance of aquatic ecosystems and their drainage basins. Quantitative chironomid-based paleoenvironmental reconstruction has so far been done only in Australia and Africa. These studies compensated for the lack of traditional surface-sediment calibration data sets, nowadays often the main source of quantitative information on species ecological optima and tolerances, by maximally exploiting archival species-distribution data based on live collections of adult and/or larval midges. This stimulated efforts to achieve trustworthy species-level identification of fossil chironomid remains, and, as a result, the taxonomic resolution of paleoecological studies in Australia and Africa is higher on average than that achieved in European and North American studies.

Rainfall reliability, a neglected factor in explaining convergence and divergence of plant traits in fire‐prone mediterranean‐climate ecosystems

ABSTRACTAim Rainfall reliability has been neglected as a determinant of plant trait convergence and divergence in mediterranean‐climate ecosystems. This paper reports on patterns of rainfall reliability — quantified as interannual variation in monthly and seasonal rainfall, and as the frequency of individual events in terms of their size, duration and intensity — for four fire‐prone mediterranean‐climate ecosystems.Location The four mediterranean‐climate regions of the world with fire‐prone ecosystems, namely SW Cape (South Africa), SW Australia, California and the Mediterranean Basin (Andalusia, Spain).Methods Using long‐term monthly rainfall data from stations dispersed across the four regions, we computed monthly means and interannual variation for each month of the year — the latter quantified as the coefficient of variation (CV) — and divided these into winter and summer seasons. We also computed the mean number of rainfall events, the mean frequency in various categories of event duration (days), the amount of rainfall per event (mm) and the rainfall intensity per event (mm/day) per year for winter and summer seasons for a subset of the rainfall stations.Results The fraction of rain falling in summer was lowest in California (5%) and similarly low (c. 25%) in the other three regions. The hierarchy of values of coefficient of variation (CV) of monthly rainfall during the winter period was as follows: California > Andalusia >> SW Cape > SW Australia; results for summer were: California > > Andalusia >> SW Australia ∼ SW Cape. SW Australian sites experienced the greatest frequency of short, small and low‐intensity rainfall events in both seasons; patterns in the SW Cape were intermediate between Australia and the two northern hemisphere sites which both received fewer, larger and more intense events. Overall, the two southern hemisphere regions (SW Australia and the SW Cape) had significantly more reliable regimes than the two northern hemisphere ones (Mediterranean Basin and California).Main conclusions These differences in rainfall reliability regimes may provide a novel perspective on the distribution of certain plant life‐history traits in mediterranean‐climate ecosystems. Less reliable regimes would select for germination and seedling survival traits that enable persistence of genets in the face of uncertain moisture conditions during the winter and spring establishment phase. Study systems that accommodate for phylogenetic constraints, namely invasive species derived from mediterranean‐climate ecosystems, as well as shared lineages, provide good opportunities to develop and test hypotheses on the implication of different rainfall reliability regimes. One of the novel implications of this study is that the distinctive trait of assemblages in the southern hemisphere regions may be a consequence not so much of their shared nutrient‐poor soils as of their similarly reliable rainfall regimes.

The Southern Hemisphere and equatorial region ionization response for a 22 September 1999 severe magnetic storm

Abstract. The ionospheric storm evolution process was monitored during the 22 September 1999 magnetic storm over the Australian eastern region, through measurements of the ionospheric Total Electron Content (TEC) from seven Global Positioning Systems (GPS) stations. The spatial and temporal variations of the ionosphere were analysed as a time series of TEC maps. Results of our analysis show that the main ionospheric effect of the storm under consideration are: the long lasting negative storm effect during a magnetic storm at mid-latitude regions; the strong, positive disturbances during the storm's main phase at auroral latitude regions; the effects of storm-induced equatorward directed wind causing a positive disturbance at high and mid-latitude stations with appropriate time shift between higher and lower latitudes; daytime poleward movement of depleted plasma that causes temporary suppression of the equatorial anomaly during the start of the storm recovery phase; and prompt penetration of eastward electric fields to ionospheric altitudes and the production of nearly simultaneous TEC enhancement at all latitudes. In general, we found dominant negative disturbance over mid and high latitudes and positive disturbance at low latitudes. A comparison of storm-time behaviour of TEC determined from GPS satellites, and foF2 derived from ionosondes at a range of latitudes, showed reasonable agreement between the two independent measurements.

Extended parental care and delayed dispersal: northern, tropical, and southern passerines compared

Using modern comparative methods, we found that both time to independence and time with parents were significantly longer in southern hemisphere and tropical birds than in northern hemisphere ones. These differences held even after removing Australian passerines or cooperatively breeding species, and they do not depend on habitat, diet, or migration pattern. In southern hemisphere and tropical regions, both cooperative breeding and non-cooperative parents continue to feed their young for a similar length of time, but cooperative breeders allow them to stay longer in their natal territory after they become nutritionally independent. Nevertheless, the young of non-cooperative species stay longer with their parents than do the young of non-cooperative species in the temperate northern hemisphere. The fact that extended periods of post-fledging parental care are widespread among passerines provides further empirical support for the view that life histories of southern and tropical birds are ‘slow,’ with small clutches, extended parental care, and long lifespan; parents take care of fewer young for longer. These results support recent theoretical models that predict that high adult survival and low turnover of territory owners generally favor natal philopatry. We suggest that the reasons why some species (with or without cooperative breeding) exhibit natal philopatry and others do not lie in the balance between productivity and survival of adults and of retained or dispersing offspring. Key words: Life history, delayed dispersal, parental care. [Behav Ecol 15:831–838 (2004)]

A new aspidostomatid bryozoan from the Cape Melville Formation (Lower Miocene) of King George Island, West Antarctica

Fragments of large, bilamellar aspidostomatid bryozoan colonies occur in Early Miocene glaciomarine sedimentary sequences of the Cape Melville Formation, King George Island, South Shetland Islands, West Antarctica. Investigation of the morphological characters of this aspidostomatid cheilostome shows that it represents a new species, which is described herein as Aspidostoma melvillensis sp. n. A combination of the colony-growth pattern, inferred co-occurring biota and associated sedimentary structures indicates a comparatively deep-water, outer shelf palaeoenvironmental setting. This Miocene occurrence of Aspidostoma melvillensis sp.n. emphasizes a biogeographical link with adjacent Southern Hemisphere regions during the early Neogene.

Comparisons of chlorophyll variability between the four major global eastern boundary currents

The first two years of SeaWiFS (Sea viewing Wide Field of view Sensor) data (1997–1999) are used to document the variability of large-scale surface chlorophyll patterns within the coastal region along the full latitudinal extent of each of the four major global eastern boundary currents; the California, Humboldt, Benguela and Canary Currents. Seasonal chlorophyll patterns are compared to coincident seasonal cycles of Ekman transport calculated from satellite scatterometer data. In all four regions, maximum chlorophyll concentrations are generally temporally and latitudinally coincident with the seasonal maximum in upwelling (offshore Ekman transport) over most of their latitudinal range, but exceptions are documented. Interannual differences are evident in each region, most notably in the two Pacific regions where the 1997–1998 chlorophyll seasonality was affected by El Niño conditions. Significant differences between previously published chlorophyll seasonality deduced from the relatively sparse coverage of the Coastal Zone Color Scanner (CZCS) and the more complete coverage of SeaWiFS in both Southern Hemisphere regions are evident.

Syntaxonomy and zonation patterns in coastal salt marshes of the Uilkraals Estuary, Western Cape (South Africa)

Vegetation on salt marshes of the Uilkraals Estuary (near Gansbaai, Western Cape, South Africa) is described and classified into 11 associations and/or rank-less plant communities (further subdivided into a number of sub-units). These communities were grouped into 6 high-rank syntaxa (alliances and community groups of preliminary syntaxonomic status). The Salicornion meyerianae, Sarcocornion decumbentis, Spergulario mediae-Puccinellion angustae, Samolo porosi-Juncion kraussii and Crassulo glomeratae-Sarcocornion capensis were described as new alliances. The dominating species in this estuarine system comprise Salicornia meyeriana, Sarcocornia perenni agg., S. capensis, S. decumbens, Bassia diffusa, Limonium sp. nova, Juncus kraussii subsp. kraussii, Sporobolus virginicus, Triglochin bulbosa etc. Zonation patterns in the salt marsh are characterised and compared to analogous vegetation in Europe and some Southern Hemisphere regions. This paper lays a foundation stone for the definition of a formal syntaxonomic system of South African salt marshes.

Influenza Activity-- United States and Worldwide, April-October 2000

During October 1999-May 2000, influenza A(H3N2), A(H1N1), and B viruses were identified in the Northern Hemisphere. Influenza A(H3N2) predominated, but the number of influenza A(H1N1) viruses increased toward the end of the influenza season in the Northern Hemisphere. Since April, influenza A viruses have predominated in the Southern Hemisphere and tropical regions, but influenza B viruses also have been identified. This report summarizes influenza activity in the United States and worldwide from April 2000 through October 2000.