Alkalibacter mobilis sp. nov., an anaerobic bacterium isolated from a coastal lake

A novel anaerobic chemoorganotrophic, facultatively alkaliphilic bacterium (strain M17 DMBT) was isolated from a coastal lake (Golubitsckoe, Taman Peninsula, Russia). Cells were motile rods, 1.6–2.1 µm long and 0.45 µm in diameter. The temperature range for growth was 14–42 °C, with an optimum at 30 °C. The pH range for growth was pH 5.5–10.0, with an optimum at pH 8.0–8.5. Growth of strain M17 DMBT was observed at NaCl concentrations of 1–12 % (w/v) with optimum growth at 1.5–2.0 %. Strain M17 MBTutilized glucose, fructose, sucrose, ribose, mannose, raffinose, arabinose, dextrin, yeast extract, peptone, carbon monoxide, vanillic acid and 3,4-dimethoxybenzoic acid. The end products from glucose fermentation were acetate and ethanol. The DNA G+C content of strain M17 DMBT was 39.1 mol%. The closest phylogenetic relative of strain M17 DMBT was Alkalibacter saccharofermentans with 97.8 % 16S rRNA gene sequence similarity. The OrthoANI value between M17 DMBT and A. saccharofermentans was 70.4 %. Based on the phenotypic, genotypic and phylogenetic characteristics of the isolate, strain M17 DMBT is considered to represent a novel species of the genus Alkalibacter for which the name Alkalibacter mobilis sp. nov. is proposed. The type strain of Alkalibacter mobilis is M17 DMBT (=KCTC 15920T=VKM B-3408T).

An ecosystem services perspective of Lake Wairarapa: Insights from the past, present, and toward the future

<p>Ecosystem services encompass the wide range of intrinsic and extrinsic benefits that humans derive from ecosystems and how such services contribute to community wellbeing. The delivery of effective and efficient provisioning, regulating, and cultural ecosystem services at Lake Wairarapa (a shallow, super-trophic, coastal lake in the lower North Island) has been heavily impacted through current land use. Using a pragmatic epistemology and mixed methods approach, this research sought to understand the past, present, and future delivery of ecosystem services at Lake Wairarapa through three distinct, yet complementary, studies. Firstly, a palaeo-environmental reconstruction using five proxies was completed to build an understanding of past environmental conditions at Lake Wairarapa. Prior to human arrival, the lake was stable and resilient in response to environmental perturbations. However, alteration of the landscape following human arrival has reduced ecosystem service effectiveness, prompting a transition into an entirely new environmental state at Lake Wairarapa. This chapter highlighted the abrupt removal of mānuka and centennial shift from a forest catchment into one dominated by agriculture so a field trial was conducted to assess the ability of mānuka to reduce nitrogen leaching and E. coli contamination. Mānuka can significantly reduce the conversion of ammonium to nitrate compared to pasture, thus regulating nitrate leaching; however, the impact on E. coli counts was less conclusive. Finally, cultural services present at Lake Wairarapa and future community aspirations were assessed through seven semi-structured interviews of Wairarapa community members. Place attachment was recognised as the underlying factor that facilitated strong cultural service delivery. Social and environmental restoration was identified as the key vision for the future, underpinned by collaboration within resource management. From this research, four recommendations were made to enhance ecosystem service delivery at Lake Wairarapa: establishment of ecologically appropriate restoration plans, facilitated collaborative management, further investigation of environmental and economic properties of mānuka, and development of community engagement programmes. This multi-disciplinary and holistic approach outlines a pathway towards a positive and inclusive future for Lake Wairarapa and its communities.</p>

An ecosystem services perspective of Lake Wairarapa: Insights from the past, present, and toward the future

<p>Ecosystem services encompass the wide range of intrinsic and extrinsic benefits that humans derive from ecosystems and how such services contribute to community wellbeing. The delivery of effective and efficient provisioning, regulating, and cultural ecosystem services at Lake Wairarapa (a shallow, super-trophic, coastal lake in the lower North Island) has been heavily impacted through current land use. Using a pragmatic epistemology and mixed methods approach, this research sought to understand the past, present, and future delivery of ecosystem services at Lake Wairarapa through three distinct, yet complementary, studies. Firstly, a palaeo-environmental reconstruction using five proxies was completed to build an understanding of past environmental conditions at Lake Wairarapa. Prior to human arrival, the lake was stable and resilient in response to environmental perturbations. However, alteration of the landscape following human arrival has reduced ecosystem service effectiveness, prompting a transition into an entirely new environmental state at Lake Wairarapa. This chapter highlighted the abrupt removal of mānuka and centennial shift from a forest catchment into one dominated by agriculture so a field trial was conducted to assess the ability of mānuka to reduce nitrogen leaching and E. coli contamination. Mānuka can significantly reduce the conversion of ammonium to nitrate compared to pasture, thus regulating nitrate leaching; however, the impact on E. coli counts was less conclusive. Finally, cultural services present at Lake Wairarapa and future community aspirations were assessed through seven semi-structured interviews of Wairarapa community members. Place attachment was recognised as the underlying factor that facilitated strong cultural service delivery. Social and environmental restoration was identified as the key vision for the future, underpinned by collaboration within resource management. From this research, four recommendations were made to enhance ecosystem service delivery at Lake Wairarapa: establishment of ecologically appropriate restoration plans, facilitated collaborative management, further investigation of environmental and economic properties of mānuka, and development of community engagement programmes. This multi-disciplinary and holistic approach outlines a pathway towards a positive and inclusive future for Lake Wairarapa and its communities.</p>

Chronostratigraphic palaeo-climate phasing based on southern African wetlands: From the escarpment to the eastern seaboard

This paper aims to identify chronostratigraphic palaeo-climatic boundaries based on proxy indications from mountain- and coastal wetlands in eastern South Africa and Lesotho. Phase boundaries were identified from timing of climate change inferred by proxies, as well as regime shifts in climate variability. Sometimes magnitude and/or frequency of change was also considered. Summarizing the common palaeo-climatic indications suggest the following chronostratigraphic climate phases: 25 to 18 ka, 18 to 15 ka, 15 to 11.5, 11.5 to 8 ka, 8 to 5.5 ka, 5.5 to 2 ka and 2 to 0 ka. The most robust boundaries were identified at 18 ka, 15 ka and 2 ka, i.e. these boundaries were supported by several proxies/sites. The other boundaries were less clearly detected from available proxies/sites and should be regarded tentative. The timing of a climate shift often coincides at coast and mountain sites. However, the climate conditions within each chronostratigraphic phase sometimes vary between coast and inland sites. The 25 to 18 ka phase was cool and dry with strong and frequent storms, followed by the ca. 18 to 15 ka period when conditions were less severe but still generally cool and dry. At ca. 15 to 11.5 ka several proxies infer warmer climate, with less winter rains. During 11.5 to 8 ka a general increase in wetness is inferred, followed by warming over the 8 to 5.5 ka phase. Between 5.5 and 2 ka a successive change towards wetter is indicated, although timing differ between sites. After 2 ka generally a more variable climate is seen, often with high magnitude shifts between dry and wet. The data resolution, i.e. the number of available wetland records, increases with time from very low during glacial times, to highest resolution during late Holocene. Geographically, sites in the mountain region are overrepresented compared to coastal sites. A comparison with coastal lake records suggests a more variable climate at coastal sites compared to mountain sites during mid- and late Holocene, although different proxy resolution and methodology cannot be ruled out as an explanation. A case study compares multiproxy records from Drakensberg (Sekhokong, Ntsikeni) and the coast (Mfabeni), discussing advantages and problems associated with proxy-comparisons within and between sites.

Aspects of the Biology of Juvenile Freshwater Eels (Anguillidae) in New Zealand

<p>The early freshwater life of the two species of New Zealand freshwater eels, Anguilla australis schmidtii Phillipps and A. dieffenbachii Gray was studied involving an examination of 8131 glass-eels, 5275 migratory elvers, and 4291 resident eels of less than 26 cm. Most eels were collected from the Makara Stream, Wellington by set-net, hand-net and electric fishing. These extensive samples together with subsidiary collections from elsewhere in New Zealand show that glass-eels of both species arrive in fresh-water from July to December. Their otoliths indicate a marine larval life of about 18 months but it is not possible as yet to locate the precise oceanic spawning areas. Migratory movements of glass-eels are in two phases: an invasion of fresh-water from the sea and an upstream migration. The former occurs only at night with a periodicity corresponding to the daily ebb-flood tidal rhythms. There is a seasonal reversal in this response which is attributable to the onset of the behavioural transition taking place prior to the second migratory phase. Increased pigmentation and changes in response to light, flowing fresh-water and schooling tendencies characterise this latter migration which occurs primarily at spring tide periods. Such juvenile eels show specific habitat preferences and a high degree of olfactory differentiation of water types. This behaviour, together with pigment development and physical tolerances, was studied in the laboratory. Measurements of invading glass-eels show that mean length, weight and condition all decline throughout the season of arrival but mean vertebral numbers remain constant. An upstream migration of small eels (elvers) occurs each summer and is readily observed at many hydro-electric stations. These migrations, comprising eels of mixed sizes and age groups, penetrate progressively further upstream each year. In both species, scales begin formation at body lengths of 16.5-20 cm. All features of scale formation, including the number of scale rings, are related to length with relative differences in rate of development occurring between the species. In contrast to scale rings, otolith rings are annual in formation and become visible after grinding or burning the otolith. Growth rates established for 273 eels to 29 cm in length from the Makara Stream, Wellington, are slow, with mean annual increments of 2.2 and 2.1 cm respectively for shortfins and longfins. In contrast, shortfins from a coastal lake near Wellington reach 26 cm in their third year of freshwater life. Length-weight relationships for small eels are given together with mean monthly condition factors. Growth studies on elvers held in a multiple tank unit in which temperature, density, and amount and frequency of feeding could be controlled, show that young eels grow more slowly than normal under such conditions. However, growth appears optimum at 20 degrees C with a feeding rate of 5-7% body weight per day. Feeding efficiency decreases with higher temperatures. At both glass-eel and elver stages, shortfins adapt and survive better under artificial conditions.</p>

Aspects of the Biology of Juvenile Freshwater Eels (Anguillidae) in New Zealand

<p>The early freshwater life of the two species of New Zealand freshwater eels, Anguilla australis schmidtii Phillipps and A. dieffenbachii Gray was studied involving an examination of 8131 glass-eels, 5275 migratory elvers, and 4291 resident eels of less than 26 cm. Most eels were collected from the Makara Stream, Wellington by set-net, hand-net and electric fishing. These extensive samples together with subsidiary collections from elsewhere in New Zealand show that glass-eels of both species arrive in fresh-water from July to December. Their otoliths indicate a marine larval life of about 18 months but it is not possible as yet to locate the precise oceanic spawning areas. Migratory movements of glass-eels are in two phases: an invasion of fresh-water from the sea and an upstream migration. The former occurs only at night with a periodicity corresponding to the daily ebb-flood tidal rhythms. There is a seasonal reversal in this response which is attributable to the onset of the behavioural transition taking place prior to the second migratory phase. Increased pigmentation and changes in response to light, flowing fresh-water and schooling tendencies characterise this latter migration which occurs primarily at spring tide periods. Such juvenile eels show specific habitat preferences and a high degree of olfactory differentiation of water types. This behaviour, together with pigment development and physical tolerances, was studied in the laboratory. Measurements of invading glass-eels show that mean length, weight and condition all decline throughout the season of arrival but mean vertebral numbers remain constant. An upstream migration of small eels (elvers) occurs each summer and is readily observed at many hydro-electric stations. These migrations, comprising eels of mixed sizes and age groups, penetrate progressively further upstream each year. In both species, scales begin formation at body lengths of 16.5-20 cm. All features of scale formation, including the number of scale rings, are related to length with relative differences in rate of development occurring between the species. In contrast to scale rings, otolith rings are annual in formation and become visible after grinding or burning the otolith. Growth rates established for 273 eels to 29 cm in length from the Makara Stream, Wellington, are slow, with mean annual increments of 2.2 and 2.1 cm respectively for shortfins and longfins. In contrast, shortfins from a coastal lake near Wellington reach 26 cm in their third year of freshwater life. Length-weight relationships for small eels are given together with mean monthly condition factors. Growth studies on elvers held in a multiple tank unit in which temperature, density, and amount and frequency of feeding could be controlled, show that young eels grow more slowly than normal under such conditions. However, growth appears optimum at 20 degrees C with a feeding rate of 5-7% body weight per day. Feeding efficiency decreases with higher temperatures. At both glass-eel and elver stages, shortfins adapt and survive better under artificial conditions.</p>

New estimates of the magnitude of the sea-level jump during the 8.2 ka event

We analyzed sediment cores from coastal Lake Izabal, Guatemala, to infer Holocene biogeochemical changes in the lake. At ca. 8370 calibrated yr B.P. (cal. yr B.P.), marine waters entered the lake, which presently lies ~38 km from the Caribbean coast. Temporal correlation between Early Holocene drainage of high-latitude Lakes Agassiz and Ojibway (in North America) and marine flooding of Lake Izabal suggests a causal link between the two processes. Our data indicate a relative sea-level jump of 2.60 ± 0.88 m, which is larger than previous estimates of sea-level rise during the 8.2 ka event. The inferred sea-level jump, however, cannot be explained solely by the volume of water released during drainage of Lakes Agassiz and Ojibway. Instead, we propose that previous studies underestimated the magnitude of Lakes Agassiz and Ojibway discharge, or that additional meltwater sources contributed to global sea-level rise at that time.

Water in the Wilderness: The Group of Seven and the Coastal Identity of Lake Superior

This paper challenges the wilderness ideology with which the Group of Seven’s coastal landscapes of the north shore of Lake Superior are often associated. Focusing my analysis around key works by Lawren Harris, A.Y. Jackson, J.E.H. MacDonald, and Franklin Carmichael, I offer an alternative perspective on commonly-adopted national and wilderness narratives, and instead consider these works in line with an emergent ecocritical consciousness. While a conversation about wilderness in relation to the Group of Seven often ignores the colonial history and Indigenous communities that previously inhabited coastal Lake Superior, this paper identifies these within a discussion of the environmental history of the region. That the environment of the north shore of Lake Superior was a primordial space waiting to be discovered and conquered only seeks to ratify the landscape as a colonial space. Instead, by engaging with the ecological complexities and environmental aesthetics of Lake Superior and its surrounding shoreline, I challenge this colonial and ideological construct of the wilderness, accounting for the prevailing fur trade, fishing, and lumber industries that dominated during the nineteenth and early twentieth centuries. A discussion of environmental history and landscape painting further allows for a consideration of both the exploitation and preservation of nature over the course of the twentieth century, and looks beyond the theosophical and mystical in relation to the Group’s Lake Superior works. As such, the timeliness of an ecocritical perspective on the Group of Seven’s landscapes represents an opportunity to consider how we might recontextualize these paintings in a time of unprecedented anthropogenic climate change, while recognizing the people and history to whom this land traditionally belongs.