Diversity of meiofauna in the lacustrine profundal zone: Bathymetric differences and influence of environmental factors

The diversity and species richness of total meiofauna, Harpacticoida and Oligochaeta in relation to depth and other environmental variables were studied at nine stations and in two profundal depth zones in Lake Päijänne which includes both oligotrophic and eutrophicated or organically loaded areas.Diversity was on average higher in the upper part of the profundal zone than at maximum depths. This may show that the greater temporal stability in temperature at greater depths does not surpass the effect of the lower temporal stability in oxygen content. The productivity factor may be a more important reason for the bathymetric difference in diversity than the stability factor. Diversity in the lower profundal zone shows a negative correlation with variables indicating pollution while in the upper profundal zone a positive one with those variables, thus emphasizing the importance of the production factor in determining diversity in the upper profundal. Diversity was higher within the oligochaetes than within the harpacticoids, which may imply that oligochaetes have a longer evolutionary history as part of the lacustrine benthic system.Of the environmental variables, phytoplankton biomass had the highest influence on total diversity in the lower profundal zone, oxygen being next in importance. The sedimentation of organic matter was most important in the upper part of the profundal zone, where oxygen did not have any significant effect on diversity. Some explaining factors determining bathymetric diversity differences are discussed in relation to the theoretical expectations.     

Assessment of a Mediterranean shallow lentic ecosystem (Lake Pamvotis, Greece) using benthic community diversity: Response to environmental parameters

Macroinvertebrates play a key role in freshwater lentic and lotic ecosystems. The macroinvertebrate benthic community of a shallow Mediterranean lake (Lake Pamvotis, NW Greece) was studied. The benthic assemblage was sampled monthly at five sites during a period of 1 year (Apr. 1998–Mar. 1999). In addition hypolimnetic water quality variables were monitored over the same period at each site.

The aim of the study was (a) to describe the intra-annual and spatial variability in benthic communities, (b) to relate possible community changes to environmental conditions and (c) to evaluate the responses of the lake's ecological status on community indices.

The benthic fauna of Lake Pamvotis was found to be very limited with a total of 10 species belonging to five taxonomic groups. The oligochaete community comprised 80% of the total benthic fauna with Potamothrix bavaricus as a new record for the Lake Pamvotis and Potamothrix hammoniensis, being the dominant benthic species represented more than 61% of the total benthic fauna. Chironomus plumosus was the most abundant chironomid species contributing with about 6% of the total benthic fauna, and Chaoborus flavicans with 19% was the important dipteran. Almost all benthic species showed the same intra-annual seasonal pattern, with peak population densities during spring and early summer except P. hammoniensis which predominated during the whole sampling period. Dissolved oxygen and temperature seemed to be the main environmental factors affecting community indices.

Benthic communities are affected by human disturbances in Lake Pamvotis shifting their composition to more tolerant taxa, reflecting also the eutrophic to hypertophic character of the lake.     

Elevational patterns of abundant and rare bacterial diversity and composition in mountain streams in the southeast of the Tibetan Plateau

Elevational gradients are powerful ‘natural laboratory' for testing the responses of microbes to geophysical influences. Microbial communities are normally composed of a few abundant and many rare taxa. Abundant and rare taxa play different ecological roles in kinds of environments, but how their diversity and composition patterns response to elevation gradients is still poorly elucidated. In this study, we investigated the elevational patterns of abundant and rare bacterial diversity and composition in a mountain stream from 712 to 3435 m at Gangrigabu Mountain on the Tibetan Plateau, China. Our results revealed abundant and rare bacteria had similar decreasing elevation trend of alpha diversity, and both of them showed a significant elevational distance-decay relationship. However, the turnover rate of the elevational distance-decay of rare bacteria was higher than that of abundant bacteria. The species-abundance distribution patterns of rare taxonomic composition were associated with the elevational gradient, while most of abundant bacterial clades did not display any relationships with elevation.Our results suggested that rare bacteria were more sensitive to changes in elevation gradient.     

Influence of macrofauna long-term natural variability on benthic indices used in ecological quality assessment

An essential prerequisite for the assessment of the ecological quality of marine ecosystems is the understanding of the natural variability and its effect on the performance of quality indices. This study is focused on the long-term natural variability of diversity, biotic and multimetric indices by using long-term macrofauna data of a coastal area in the southern North Sea (1978-2005). The univariate and most biotic and multimetric indices respond significantly on specific natural disturbance events such as cold winters, but the strength of response varied between indices as well as between events. As a result, the ecological quality status can decrease over a range of 3 (out of 5) classification units. The overall ecological quality was good to high, but an increase of indices occurred from the mid 1980s onwards due to changes in the climate regime. This long-term variability has to be considered within ecological quality assessment schemes.     

Biological assessment of the Zayandeh Rud River, Iran, using benthic macroinvertebrates

Benthic macroinvertebrate communities from the middle of Zayandeh Rud River were analyzed monthly during 1 year at 8 stations, in order to assess changes in their diversity and richness in relation to water quality. Two major groups of sites based on similarity between macroinvertebrate communities were identified by cluster analysis. The performances of the original and revised BMWP score systems were assessed by comparing the community structure indices of benthic macroinvertebrates along with physico-chemical parameters of the water. The biotic indices (BMWP, ASPT, revised BMWP and ASPT) showed better correlation with water quality parameters than that of the richness and diversity indices. The revised ASPT had the highest correlation with water quality parameters. It seems that the application of the revised BMWP score system could be useful for assessment of the water quality in Zayandeh Rud River.     

Stories from the IPCC: An essay on climate science in fourteen questions

Women’s experiences as Intergovernmental Panel on Climate Change (IPCC) authors, have been explored showing how gender, race, nationality, etc. increase barriers to participate in the production of climate science even for the best scientists. Recently, the IPCC Gender Task Force, conducted another survey exploring barriers to participation in the IPCC that included men as well as women. The Gender Task Force released a report on gendered barriers mostly focusing on quantitative responses. This paper presents a qualitative analysis of the fourteen open-ended questions in the survey. In addition to qualitative analysis, storytelling and the concept of feminist objectivity are useful approaches to convey the complicated web of responses of over 500 scientists about their experiences participating in the IPCC and in climate science more broadly. Gender, race and nationality continue to be barriers. I stress the connection between exclusions of underrepresented scientists in the IPCC with the persistent western belief that science is an objective and impartial practice. The paper brings attention to exclusionary structures that prevent participation in the IPCC and in science more broadly, but also provides stories of how these are resisted. These stories go beyond recognizing people as disadvantaged toward addressing the intersecting structures that exclude people from participating in science. As climate science becomes more diverse, and evidence points toward the benefit of diversity for superior science, understanding barriers and opportunities for scientists participating in multidisciplinary and international reports such as the IPCC becomes increasingly important. The stories provide a theoretical and methodological catalyst for international science institutions who seek to increase the influence and presence of underrepresented groups in science and produce superior science.     

Beyond total area protected: A new set of metrics to measure progress in building a robust protected area estate

With protected areas identified as the primary tool to halt the loss of biodiversity, the Convention on Biological Diversity has set targets for protected area expansion. Increasingly, concerns are being raised that target-driven growth, where targets focus largely on quantity (total area protected) rather than quality, may fail to achieve their intended biodiversity outcomes. Therefore, it is important to assess whether growth in area protected is translating into a more robust system of protected areas that better safeguard biodiversity. In this study, we propose a set of seven indicators, drawing on the body of evidence for the elements of protected area design and management associated with better biodiversity outcomes. Many of the features of effective design and management interact with one another, making it essential to use a suite of indicators and consider progress relative to trends across all of these indicators. We implemented the proposed indicators for the Australian National Reserve System, which has undergone significant growth over the past two decades. Our findings demonstrate that relying on trends in total area protected can obscure negative trends in other important indicators which suggest many protected areas in Australia are under increasing pressure. Meanwhile, the level of resourcing for management has not kept pace with increases in total area protected and has certainly not scaled with changes in pressures on protected areas. It is important that the global conservation community strive for a more nuanced set of indicators for conservation progress to identify whether growth in area protected has, or has not, translated into a more robust and effective system of protected areas. Given that most of the indicators we propose can be populated with existing data, we believe this approach could be achievable for protected areas globally.     

Local and regional species diversity of benthic Isopoda (Crustacea) in the deep Gulf of Mexico

Recent studies of deep-sea faunas considered the influence of mid-domain models in the distribution of species diversity and richness with depth. In this paper, I show that separating local diversity from regional species richness in benthic isopods clarifies mid-domain effects in the distribution of isopods in the Gulf of Mexico. Deviations from the randomised implied species ranges can be informative to understanding general patterns within the Gulf of Mexico. The isopods from the GoMB study contained 135 species, with a total of 156 species including those from an earlier study. More than 60 species may be new to science. Most families of deep-sea isopods (suborder Asellota) were present, although some were extremely rare. The isopod family Desmosomatidae dominated the samples, and one species of Macrostylis (Macrostylidae) was found in many samples. Species richness for samples pooled within sites ranged from 1 to 52 species. Because species in pooled samples were highly correlated with individuals, species diversity was compared across sites using the expected species estimator (n=15 individuals, ES₁₅). Six depth transects had idiosyncratic patterns of ES₁₅, and transects with the greatest short-range variation in topography, such as basins and canyons, had the greatest short-range disparity. Basins on the deep slope did not have a consistent influence (i.e., relatively higher or lower than surrounding areas) on the comparative species diversity. ES₁₅ of all transects together showed a weak mid-domain effect, peaking around 1200–1500 m, with low values at the shallowest and deepest samples (Sigsbee Abyssal Plain); no longitudinal (east–west) pattern was found. The regional species pool was analyzed by summing the implied ranges of all species. The species ranges in aggregate did not have significant patterns across longitudes, and many species had broad depth ranges, suggesting that the isopod fauna of the Gulf of Mexico is well dispersed. The summed ranges, as expected, had strong mid-domain patterns, contrasting with the local species richness estimates. The longitudinal ranges closely matched a randomized pattern (species ranges placed randomly, 1000 iterations), with significant deviations in the east attributable to lower sampling effort. The depth pattern, however, deviated from the mid-domain model, with a bimodal peak displaced nearly 500 m shallower than the mode of the randomized distribution. The deviations from random expectation were significantly positive above 1600 m and negative below 2000 m, with the result that regional species richness peaked between 800 and 1200 m, and decreased rapidly at deeper depths. The highest species richness intervals corresponded to the number of individuals collected. Residuals from a regression of the deviations on individual numbers, however, still deviated from the randomized pattern. In this declining depth-diversity pattern, the Gulf of Mexico resembles other partially enclosed basins, such as the Norwegian Sea, known to have suffered geologically recent extinction events. This displaced diversity pattern and broad depth ranges implicate ongoing re-colonization of the deeper parts of the Gulf of Mexico. The Sigsbee Abyssal Plain sites could be depauperate for historical reasons (e.g., one or more extinction events) rather than ongoing ecological reasons (e.g., low food supply).     

北极黄河站邻近海域浮游细菌多样性初步研究

通过荧光染色、稀释培养、生理生化和16SrRNA基因鉴定等方法,研究了北极黄河站附近海域海水中浮游细菌的丰度、可培养浮游细菌形态学特征及多样性;采用高通量测序技术研究了黄河站附近采样站点(BJ2)的不可培养浮游细菌群落结构。可培养研究结果表明:(1)9个站点(BJ1-BJ9)水样平均含菌数为2.88×108个/L;(2)21株可培养浮游细菌中,仅AB08、AB09和AB17三株细菌为革兰氏阳性菌;(3)细菌主要包括放线菌纲(Actinobacteria),黄杆菌纲(Flavobacteriia)和γ-变形菌纲(Gammaproteobacteria),其中假单胞菌属(Pseudomonas)为优势菌(占71%)。高通量测序结果显示:在得到的1 467个不可培养浮游细菌OTU中,变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)为优势菌群,所占比例分别为49.71%和41.61%,还有少量的浮霉菌门(Planctomycetes)和疣微菌门(Verrucomicrobia);其中变形菌门中以α-变形菌纲(α-Proteobacteria)为主要类群。