Seasonality in Nutrients and Phytoplankton Production in Two Shallow Lakes: Waigani Lake,Papua New Guinea,and Barton Broad,Norfolk, England

Waigani Lake, near Port Moresby, Papua New Guinea and Barton Broad, Norfolk, England are both shallow lakes nutrient-enriched from sewage effluent disposal. In Waigani Lake phytoplankton biomass varied seasonally with lower levels (100-200 mg chlorophyll α m⁻³) during the wet season increasing to over 400 mg chlorophyll α m⁻³ at the end of the dry season. Secchi disc depths varied between 0. 11 and 0. 34 m. Phytoplankton productivity in Waigani Lake was very high throughout the year (range: A_max 4,370-21,000 mg O₂ m⁻³ h⁻¹) but production was lower during the wet season (range: A_max 4,370-12,700 mg O₂ m⁻³ h⁻¹). High surface productivity was recorded from August to December except on sampling days when the weather was overcast. Productivity throughout the year declined rapidly with depth. Algal biomass in Barton Broad varied from 3-10 mg chlorophyll α m⁻³ in winter but increased in spring and was very high in summer (200-500 mg chlorophyll α m⁻³). Secchi disc depth varied from 0.21 m in August 1976 to 1.76 m in December. Phytoplankton production in Barton Broad was low in winter (range: A_max 247-1,250 mg O₂ m⁻³ h⁻¹) but increased markedly in spring and summer with the highest rate (A_max 6,850 mg O₂ m⁻³ h⁻¹) being recorded in August. Surface inhibition was observed during summer except when the weather was overcast. Seasonality in nutrients and phytoplankton in Waigani Lake appear to be related to rainfall. Nutrient concentrations in Barton Broad are more closely related to phytoplankton activity which, in turn, correlates with seasonality in solar radiation.     

New records of rotifers from the South Island lakes,New Zealand

Thirty-five lakes in the South Island of New Zealand were surveyed for rotifers during 1988–1991. Of 85 taxa identified, 31 are first records for New Zealand, bringing the rotifers recorded from the country to 331. Four species (Keratella australis, K. slacki, Lecane herzigi and L. tasmaniensis), previously recorded as endemic forms only in Australia, are now added to the New Zealand checklist. Several of the new records are photographed, and scanning electron micrographs of the trophi are shown. Comments are made on the Australasian endemics and rotifer biogeography in New Zealand.     

Phytoplankton as an Indicator of the Water Quality of the Deep Lakes South of the Alps

This paper offers a synoptic account of studies on the phytoplankton communities in the deep southern subalpine lakes (DSL) Garda, Iseo, Como, Lugano and Maggiore. The main cause of the degradation of the water quality in the DSL is eutrophication. The euphotic layers of these lakes are trophically different, ranging from the oligo-mesotrophy of lakes Maggiore and Garda to the meso-eutrophy of lakes Iseo and Lugano. The trophic status as estimated by using total phosphorus and chlorophyll a has provided consistent results in agreement with the models proposed by OECD (1982. Eutrophication of Waters. Monitoring, Assessment and Control, OECD, Paris). Though related with chlorophyll a and TP, the Secchi disk depths have significantly underestimated the trophic status of the DSL. Two trophic indices using the algal orders (PTI_orders) and species (PTI_species) were drawn up on the basis of the distribution of phytoplankton along a trophic gradient defined by the application of multivariate methods; the scores emerging from these indices were used to make a definitive ecological classification of water bodies on a scale from 1 to 5, in accordance with the Water Framework Directive. A third index (PTI_OE) was computed as the ratio between the annual mean values of the cumulative biovolumes of two groups of algal orders with opposite trophic characteristics. The three PTI indices were highly correlated, providing a consistent classification of the water bodies. The indices proposed in this work were specifically adopted for use in the DSL. However, the criteria for their implementation constitute a robust and impartial tool for assessing similar indices in other lake typologies and for evaluating the degree of specificity of the trophic indicator values assigned to the single phytoplankton orders and species.     

Phytoplankton succession in Lake Valencia,Venezuela

Phytoplankton counts and supporting physical and chemical data were taken on Lake Valencia, Venezuela, over a five-year interval. The data are used to test the validity of a successional paradigm for class-level taxa. According to the paradigm, formulated from previous studies of Lake Lanao, Philippines, and from data on temperate lakes, the order of taxa from early to late succession is: diatoms, chlorophytes, blue-green algae, dinoflagellates. A successional episode is considered to begin when stability of a water column is restored after deep mixing. As the episode progresses, there is a steady decrease in concentration of the limiting macronutrient (in this case, N). In a test of the validity of the paradigm for Lake Valencia, dates of exceptional population increase or decrease were obtained for each taxon. Since nitrate concentration declines steadily as succession progresses, the entry of a given taxon into the successional sequence is indicated quantitatively by the mean nitrate concentration on dates of exceptional increase in population density, and exit from the successional sequence is indicated by mean nitrate concentration on dates of exceptional population declines. The successional position of each major taxon, bounded by its entry and exit in the sequence, can be mapped on the complete spectrum of nitrate concentrations observed in the lake. For Lake Valencia, the nitrate mapping procedure agrees exactly with the predictions based on the successional paradigm. Conformance of Lake Valencia phytoplankton with predictions made a priori suggests that there is a generalized pattern in the phytoplankton succession of the mixed layers of temperate and tropical lakes.     

Macrophyte depth limits in North Island (New Zealand) lakes of differing clarity

The seasonal variation in water clarity, as indicated by the attenuation coefficient for photosynthetically active radiation, K _d (m^-1), was determined by monthly measurements for a year in 9 North Island, New Zealand lakes. K _d varied by a factor of 2 to 3 in 8 of the lakes, and a factor of 5 in one. Annual mean K _d (symbol% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4saaaa!36BD!\[K\] _d) varied by a factor of approximately 15 between lakes. The maximum depth of water colonized by macrophytes (z _c)was also determined. Values of z _c were in the range 1.5–12.5 m. The relationship z _c =4.34/% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4saaaa!36BD!\[K\]_d accounted for most (93 percent) of the variability in z _c , indicating that average annual clarity was probably a useful predictor of z _c in lakes in this region. The values of z _c in these North Island lakes were generally greater than values calculated using previously published empirical relationships derived for northern hemisphere groups of lakes. The extent to which these relationships underestimated z _c in the North Island lakes was broadly related to latitude. Estimated average irradiance at z _c in each lake was similar to compensation point irradiances reported previously for freshwater macrophytes.     

New species of Euptyctima (Acari,Oribatida) from New Zealand

Abstract

Oribotritia contortula n. sp., O. contraria n. sp., O. teretis n. sp., Rhysotritia bifurcata n. sp., Microtritia contraria n. sp., M. glabrata n. sp., Hoplophthiracarus bisulcus n. sp., Austrophthiracarus pulchellus n. sp., and Notophthiracarus claviger n. sp. are described from New Zealand.

The genera of Oribotritia Jacot, Rhysotritia Märkel & Meyer, Hoplophthiracarus Jacot, and Austrophthiracarus Balogh & Mahunka are new records for New Zealand.     

Fire and ice: volcanic and glacial impacts on the phylogeography of the New Zealand forest fern Asplenium hookerianum

In the Southern Hemisphere there has been little phylogeographical investigation of forest refugia sites during the last glacial. Hooker's spleenwort, Asplenium hookerianum, is a fern that is found throughout New Zealand. It is strongly associated with forest and is a proxy for the survival of woody vegetation during the last glacial maximum. DNA sequence data from the chloroplast trnL-trnF locus were obtained from 242 samples, including c. 10 individuals from each of 21 focal populations. Most populations contained multiple, and in many cases unique, haplotypes, including those neighbouring formerly glaciated areas, while the predominant inference from nested clade analysis was restricted gene flow with isolation by distance. These results suggest that A. hookerianum survived the last glacial maximum in widespread populations of sufficient size to retain the observed phylogeography, and therefore that the sheltering woody vegetation must have been similarly abundant. This is consistent with palynological interpretations for the survival in New Zealand of thermophilous forest species at considerably smaller distances from the ice sheets than recorded for the Northern Hemisphere. Eastern and central North Island populations of A. hookerianum were characterized by a different subset of haplotypes to populations from the remainder of the country. A similar east-west phylogeographical pattern has been detected in a diverse array of taxa, and has previously been attributed to recurrent vulcanism in the central North Island.     

Limnology and plankton periodicity of Jos Plateau water reservoir,Nigeria, West Africa

Limnological data (Dec. 1980–Jan. 1982) on the plankton and water chemistry of Lamingo Dam, located within the Jos biotite granite area of the Plateau State (Nigeria) are presented. The water-body falls in Beadle's (1981) category I of African lakes (conductivity < 40 µS cm^–1). Alkalinity (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0Jf9crFfpeea0xh9v8qiW7rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmiEayaara% aaaa!3914!\[\bar x\] = 0.3 meq l^–1), principally composed of bicarbonates, dominated the anions % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0Jf9crFfpeea0xh9v8qiW7rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaK4waiaajI% eacaqIdbGaaK4tamaaxababaGaeyOeI0caleaacaaIZaaabeaakiaa% b6dacaqIdbGaaKiBaiaaj2cacaqG+aGaaK4uaiaaj+eadaqhaaWcba% GaaKinaaqaaiaajkdacaqITaaaaOGaaKyxaaaa!4657!\[\user1{[HCO}\mathop -\limits_3 {\text{ > }}\user1{Cl - }{\text{ > }}\user1{SO}_\user1{4}^{\user1{2 - }} \user1{]}\]The plankton were characterized by a moderate standing crop of phytoplankton, and zooplankton were, generally, very limited in species and abundance. The order of dominance for the categories of phyto and zooplankton was: [Bacillariophyceae > Chlorophyceae > Dinophyceae] and [Rotifera > Crustacea] respectively. A diel cycle was characterized by nocturnal upward migration of the zooplankton, and the reverse behaviour in the phytoplankton.Interrelations between the biotic assemblages of plankters and various physical and chemical variables are discussed.     

Stratigraphy of the fossil Chironomidae (Diptera) from Lake Grasmere,South Island,New Zealand,during the last 6000 years

The fossil chironomid fauna of a 3.26 m long sediment core from Lake Grasmere has been analysed. The fossil chironomid taxa belong mainly to the subgroups Tanytarsini, Orthocladiinae, Chironomini, and Tanyphodinae. Heptagyini and Podonominae were not common. Tanytarsini were the dominant component of the fauna with Corynocera sp. as the most abundant species during pre-Polynesian times (before 1000 yr BP). The abundance and the composition of the fossil chironomid taxa have fluctuated markedly over the last 6000 years. These fluctuations could be partly correlated with changes in the stratigraphy of the sediments in the core. Layers of highly minerogenic sediment contained the lowest numbers of remains whereas high abundances were found in the sections of the core with the greatest proportion of organic matter. It is suggested that major shifts in the structure of the chironomid community have been mainly caused by changes in the hydrology and inflows of the lake, and the rate and type of sedimentation, in addition to variations in lake productivity.     

New species of the genus Cyamops Melander from New Zealand (Diptera, Periscelididae, Stenomicrinae)

Two new species of the genus Cyamops (Diptera: Periscelididae), the first from New Zealand, are described. The two newly described species are: Cyamops alessandrae and Cyamops crosbyi. A key to the genera of the subfamily Stenomicrinae and to the species of Cyamops from the Australasian/Oceanian Region and detailed illustrations of structures of the male terminalia are provided.     

Calanoid copepod biogeography in New Zealand

The distribution of four calanoid copepod species of Boeckella in New Zealand are mapped and described. An explanation of their distribution patterns based on panbiogeographic methods is compared to an explanation based on dispersalist concepts. The panbiogeographic explanation is simpler, and is consistent with explanation of distribution patterns among other genera of plants, invertebrates, amphibians and birds. This revised version was published online in July 2006 with corrections to the Cover Date.     

Water quality and plankton periodicity in two contrasting mine lakes in Jos,Nigeria

Water quality and plankton periodicity was studied in two mine lakes near Jos in the younger granite area of Plateau State, Nigeria. The investigation was carried out for 8 months. Transparency, pH and NO₃-N were significantly higher in Lake II while DOM, alkalinity, PO ₄ ^3– -P, BOD and chloride were significantly higher in Lake I. The order of dominance in Lake I was Bacillariophyceae, Cyanophyceae, Chlorophyceae and Dinophyceae while for Lake II; Chlorophyceae, Cyanophyceae, Bacillariophyceae and Dinophyceae. In Lake I the zooplankton in order of dominance were Cladocera, Rotifera, Copepoda, and nauplii and in Lake II Cladocera, Copepoda, Rotifera and nauplii. Although both lakes would seem unproductive based on the PO ₄ ^3– -P and NO ₃ ^– -N levels, Lake I appears more productive than Lake II.     

Phytoplankton dynamics in a shallow,hypertrophic reservoir (Lake Arancio,Sicily)

Phytoplankton abundance and composition in the hypertrophic man-made Lake Arancio was analyzed, based on a programme of weekly sampling from May 1990 to November 1991 and supported by measurements of limnological parameters. The highest value of phytoplankton biomass (78 mg l^–1) was observed in October 1990, during a bloom of the desmid Closterium limneticum var. fallax, while the lowest (0.15 mg l^–1) was measured in April 1991. During spring, autumn and winter 1990, species of the genus Closterium dominated the community, in the sequence: C. aciculare, C. limneticum var. fallax, C. limneticum. The summer community was more diverse with the predominance of organisms belonging to Chlorophyceae (Chlamydomonas, Eudorina, Coelastrum) and Cyanophyceae (Microcystis, Anabaena). In spring 1991, there was a long clear-water phase during which small green algae (Ankyra, Oocystis) and cryptomonads dominated. Subsequently, the summer season was characterized by a clear sequence of dominants, drawn, in turns, from species belonging to: Bacillariophyceae, Dinophyceae, Cyanophyceae, Euglenophyceae. The physics of the reservoir and its depth, owing to filling/draining constraints in a summer-arid climate, appeared to play a key role in the dynamics of phytoplankton community.     

Phytoplankton and Zooplankton Associations in a Set of Alpine High Altitude Lakes: Geographic Distribution and Ecology

Species composition and interactions, biomass dominance, geographic distribution and driving variables were investigated for two key elements of the pelagic food web of Alpine lakes, the phytoplankton and the zooplankton, based on a single sampling campaign during summer 2000. Altogether, 70 lakes were surveyed, 49 of which located in three different lake districts of the west and eastern Italian Alps and 21 in the central Austrian Alps (within the uppermost Danube catchment). In addition to the analysis of environmental variables affecting distribution and species structure of the two planktonic compartments, a brief review of the main research lines and hypotheses adopted in the past for the study of phytoplankton and zooplankton in high Alpine lakes is given. The lakes, investigated partly within the European project EMERGE (EVK1-CT-1999-00032) and partly within a regional project in the eastern Alps, comprise a wide range of morphological, chemical and trophic conditions. The phytoplankton communities were found to be diverse and mostly dominated by flagellates (chrysophytes, cryptophytes and dinoflagellates), and only to a lesser extent by non-motile green algae, desmids and centric diatoms. The zooplankton communities were mainly dominated by Alpine cladocerans and copepod species, while rotifers were abundant within one group of Italian lakes (sampled in early summer). The multivariate statistical analyses (CCA) showed that catchment features (i.e. percentage of vegetation cover and geochemical composition) and nitrate concentration are essential drivers for the phytoplankton, whereas for zooplankton also trophic status of the lakes and phytoplankton structure are important. The combined variance analysis of the lake clusters outlined by the multivariate analyses on phytoplankton and zooplankton data, respectively, allowed the identification of four principal lake types (three located on siliceous and one on carbonaceous bedrock), each one characterised by a certain combination of habitat features, which in their turn influence trophic state, and phytoplankton and zooplankton species composition and functionality.     

Biography,Authenticity and Personalised Post-Mortem Practices in Aotearoa/New Zealand

Current thanatology discourse details a new ethos of openness transforming death-related practices, accentuating a shift to personalised rituals, authenticity and expressive grief. Drawing on ethnographic interviews with mourners and funeral professionals, this article explores these putative post-mortem changes and critically assesses the claims and counterclaims concerning funerary arrangements in New Zealand. While underscoring the complexity of mortuary practices, this study explicates the varying notions of authenticity that pervade the funeral discourse. Although funeral professionals emphasised the significance of grief and bereavement processes characterised by a need for honesty and transparency, bereaved participants proffered an alternative interpretation of authenticity that privileged biographical coherence and the need to confer transcendence to the dead. These findings not only emphasise the inadequacies of the aforementioned representations of post-mortem change, but elucidate the context-specific conceptualisations of authenticity and the continuing relationships between the living and the dead in Aotearoa/New Zealand.     

Species of the genus Crotonia (Acari: Cryptostigmata) from New Zealand

Five new species of Crotonia from New Zealand ( C. cervicorna, C. cupulata, C. longibulbula, C. tuberculata and C. reticulata ) are described as new, and two species ( C. cophinana (Michael 1908) and C. caudatis (Hammer 1966)) are redescribed. Five species groups of the genus are characterized and a key to the adequately described species of the world is presented.     

Hydrology and Changes in the Nutrients and Phytoplankton Levels in Goat Island Bay,Northern New Zealand

A survey of the phytoplankton and nutrient levels in Goat Island Bay, northern New Zealand was carried out in 1981–82 and the data compared with an earlier survey in 1966–69. The contribution of nutrients from the inflowing creek was also measured. The only significant change was a doubling of the dissolved nitrate levels in the sea, which appeared to be related to increased nitrate levels in the freshwater creek. It is suggested that the increase is due to an increase in the farming and recreational use of the catchment area. The standing crops of phytoplankton in the bay showed no correlation with nutrient levels, but there were significant correlations with the radiation received.     

Mitochondrial phylogeography of New Zealand freshwater crayfishes, Paranephrops spp

Tectonic movement at the boundary of the Indo-Australian and Pacific Plates during the Miocene and Pliocene is recognized as a driving force for invertebrate speciation in New Zealand. Two endemic freshwater crayfish (koura) species, Paranephrops planifrons White 1842 and Paranephrops zealandicus White 1842, represent good model taxa to test geological hypotheses because, due to their low dispersal capacity and life history, geographical restriction of populations may be caused by vicariant processes. Analysis of a mitochondrial DNA marker (cytochrome oxidase subunit I) reveals not two, but three major koura lineages. Contrary to expectation, the cryptic West Coast group appears to be more closely related to P. zealandicus than to P. planifrons and has diverged earlier than the final development (Late Pleistocene) of Cook Strait. Our date estimates suggest that koura lineage diversification probably coincided with early to mid-Alpine orogeny in the mid-Pliocene. Estimates of node ages and the phylogenies are inconsistent with both ancient Oligocene and recent postglacial Pleistocene range expansion, but suggest central to north colonization of North Island and west to east movement in South Island during mid- to late Pliocene. Crypsis and paraphyly of the West Coast group suggest that morphological characters presently used to classify koura species could be misleading.     

Phytoplankton communities of North African wetland lakes: the CASSARINA Project

Seasonal variations in phytoplankton species composition (frequencies) and densities (cell numbers) in nine North African coastal lakes selected in Morocco (Merja Sidi Bou Rhaba, Zerga and Bokka), Tunisia (Chitane, Ichkeul and Korba lakes) and Egypt (Edku, Burullus and Manzala lakes) were investigated during 1998. The main aim was to provide gase-line information about overall phytoplankton diversity and how phytoplanktoncharacteristics differ between these contrasting aquatic systems.Water samples were collected at approximately three monthly intervals and phytoplankton analysis revealed marked seasonal and spatial differences in the quantitative and qualitative composition of the communities at each site. The Egyptian lakes generally had larger crops (Manzala and Burullus had mean crop densities of more than 104 cells ml^–1) but in the western North African sites only Korba and Sidi Bou Rhaba had closely comparable densities. Algae belonging to Bacillariophyceae, Chlorophyceae, Chrysophyceae, Cyanophyceae, Dinophyceae and Euglenophyceae were recorded. Taxa representative of all these algal groups occurred in two lakes (Korba and Manzala) but at the other seven sites only some of the groups were present.The Chlorophyceae was the most dominant group in lakes Burullus, Manzala, Korba and Sidi Bou Rhaba whereas Bacillariophyceae were dominant in lakes Zerga, Bokka and Edku. In Ichkeul and acidic Chitane the Dinophyceae and the Cyanophyceae were the dominant groups, respectively. The maximum percentage of Euglenophyceae occurred in Edku Lake but this group was absent in Sidi Bou Rhaba and Ichkeul. Cyanophyceans were present in significant numbers in all investigated lakes except in Ichkeul. A total of fifty-three genera were recorded, 17 of Chlorophyceae, 18 of Bacillariophyceae, 11 of Cyanophyceae, 3 of Chrysophyceae, 2 of Euglenophyceae and 2 of Dinophyceae. The maximum number of species (34) occurred in Burullus Lake and the minimum (6) in Ichkeul Lake. Only one lake (acidic Chitane) possessed species indicative of oligotrophic conditions. The Nile Delta lakes were the most species diverse sites.The phytoplankton communities of the nine North African lakes were composed entirely of cosmopolitan species but with one new species (Cyclotella choctawatcheeana) was recorded for the region. The data presented provide a contemporary account of the levels of algal diversity present in these sites at the end of the 20th century. The relevance of phytoplankton communities to assessment of lake status and future monitoring studies in the region is emphasised.