Polar gigantism dictated by oxygen availability

The tendency of some animals to be larger at higher latitudes ('polar gigantism') has not been explained, although it has often been attributed to low temperature and metabolism. Investigation of gigantism requires widely distributed taxa with extensive species representation at many well-studied sites. We have analysed length data for 1,853 species of benthic amphipod crustaceans from 12 sites worldwide, from polar to tropical and marine (continental shelf) to freshwater environments. We find that maximum potential size (MPS) is limited by oxygen availability

Metabolism and chemical composition of zooplankton from 500 to 5,000 m depth of the western subarctic Pacific Ocean

Respiration (=oxygen consumption) rates of 28 zooplankton species belonging to 10 taxa from 500-5,000 m depth of the western subarctic Pacific Ocean were determined as 0.027-0.44 μLO2 mg dry mass^[-1] h^[-1] at in situ temperatures (1.5-3℃), which are 80% lower than the rates of the epipelagic Antarctic zooplankton with similar body mass and at a comparable temperature. In terms of Adjusted Metabolic Rate to 1 mg body N (AMR; μLO2 mg N^[-0.8]h^[-1]) at 1℃, the present results (mean: 1.66) fall well within the range (0.84-3.32) reported for copepods, chaetognaths, and mixed crustaceans from 500-7,000 m in the subarctic Pacific Ocean and Antarctic waters. Judging from their body C:N elemental ratios and ash-free dry mass (=organic matter) data, the major component of organic matter is deduced to be protein (C:N = 3.4-8.1, by mass) for 19 out of 28 species and lipids (C:N = 8.6-13.0) for the remaining 9 species

The Baltic Sea spring phytoplankton bloom in a changing climate: an experimental approach

The response of the Baltic Sea spring bloom was studied in mesocosm experiments, where temperatures were elevated up to 6°C above the present-day sea surface temperature of the spring bloom season. Four of the seven experiments were carried out at different light levels (32–202 Wh m −2 at the start of the experiments) in the different experimental years. In one further experiment, the factors light and temperature were crossed, and in one experiment, the factors density of overwintering zooplankton and temperature were crossed. Overall, there was a slight temporal acceleration of the phytoplankton spring bloom, a decline of peak biomass and a decline of mean cell size with warming. The temperature influence on phytoplankton bloom timing, biomass and size structure was qualitatively highly robust across experiments. The dependence of timing, biomass, and size structure on initial conditions was tested by multiple regression analysis of the y-temperature regressions with the candidate independent variables initial light, initial phytoplankton biomass, initial microzooplankton biomass, and initial mesozooplankton (=copepod) biomass. The bloom timing predicted for mean temperatures (5.28°C) depended on light. The peak biomass showed a strong positive dependence on light and a weaker negative dependence on initial copepod density. Mean phytoplankton cell size predicted for the mean temperature responded positively to light and negatively to copepod density. The anticipated mismatch between phytoplankton supply and food demand by newly hatched copepod nauplii occurred only under the combination of low light and warm temperatures. The analysis presented here confirms earlier conclusions about temperature responses that are based on subsets of our experimental series. However, only the comprehensive analysis across all experiments highlights the importance of the factor light

The urban question in Harvey and Castells: Political economy vision and its constraints

Bu yazıda, kent sosyolojisinin en temel yöntem sorunsalı olan ‘kentin teorik bir nesne(obje) olarak’ kabul edilip edilemeyeceği konusu; Marksçı kentsel teorinin politik ekonomi vizyonunun yaklaşımları temelinde ele alınmaktadır. Marksçı kentsel teorinin içerisinde çeşitli varyantlar bulunmakla beraber, politik ekonomi vizyonu olarak adlandırılan yaklaşımın, bu teorinin genel eğilimlerini yansıtabilme noktasında yalnızca bir “ideal tip” oluşturduğu belirtilmelidir. Politik ekonomi vizyonunun temsilcileri olan Harvey ve Castells’in klasik çalışmalarında ise kent, teorik bir öneme sahip değildir. Kendisini kuşatan sosyal süreçlere bağlı olumsal(contingent) bir değişkendir. Bu yazıda, Harvey ve Castells’in kente yaklaşımları ele alınarak teorik kısıtları gösterilmeye çalışılmakta ve Marksçı yöntem için söz konusu edilen kısıtların Weberci yöntemle aşılabileceği ileri sürülmektedir.This article deals with the most essential methodological issue of the urban sociology, i.e. the question whether "the urban can be considered as a theoretical object or not", based on the approaches of political economy vision of the Marxist urban theory. While there are various variants in Marxist urban theory, it should be pointed out that the approach referred to as political economy vision constitutes only an "ideal type" in reflecting the general tendency of this theory. The classical studies of Harvey and Castells, being the representatives of political economy vision, do not attribute a theoretical importance on 'urban'. It is rather considered as a contingent variable depending upon surrounding social processes. This article discusses the urban approaches of Harvey and Castells with an effort to reveal their theoretical constraints, and puts forward that the constraints applying to Marxist methodology can be overcome by Weber's methodology