Eulerian and Lagrangian properties of biophyscial intermittency in the ocean

2000 FLORIDA AVE NW, WASHINGTON, USA, DC, 2000

Towards a Standardized Approach of Cetacean Habitat: Past Achievements and Future Directions

The understanding of what habitat means for an organism as well as the underlying factors driving patterns of habitat use is still unknown for many species. Cetacean habitat has been described using a range of methodologies and variables measured over various temporal and spatial scales that are often author-dependent. However, in order to develop an objective and sound understanding of what habitat actually means for cetaceans, a standardized approach needs to be developed. Here, after briefly reviewing the fundamental differences between terrestrial and marine habitats, we highlight the difficulty in defining a marine habitat, with a special focus on marine mammals. We subsequently provide six recommendations by which future cetacean habitat studies might be approached. This recommended approach aims to amend the way in which we think about and undertake investigations into cetacean habitat. It is believed that through this broadened approach, future cetacean habitat studies will increase our understanding of underlying driving factors of cetacean habitat, rather than just describing distribution patterns. Finally, it is stressed how the proposed approach will be more directly applicable within management frameworks and of benefit to conservation initiatives

Indo-Pacific bottlenose dolphin (Tursiops aduncus) habitat preference in a heterogeneous, urban, coastal environment

Background: Limited information is available regarding the habitat preference of the Indo-Pacific bottlenose dolphin (Tursiops aduncus) in South Australian estuarine environments. The need to overcome this paucity of information is crucial for management and conservation initiatives. This preliminary study investigates the space-time patterns of habitat preference by the Indo-Pacific bottlenose dolphin in the Port Adelaide River-Barker Inlet estuary, a South Australian, urbanised, coastal environment. More specifically, the study aim was to identify a potential preference between bare sand substrate and seagrass beds, the two habitat types present in this environment, through the resighting frequency of recognisable individual dolphins. Results: Photo-identification surveys covering the 118 km2 sanctuary area were conducted over 2 survey periods May to August 2006 and from March 2009 to February 2010. Sighting frequency of recognisable individual Indo-Pacific bottlenose dolphins established a significant preference for the bare sand habitat. More specifically, 72 and 18% of the individuals sighted at least on two occasions were observed in the bare sand and seagrass habitats respectively. This trend was consistently observed at both seasonal and annual scales, suggesting a consistency in the distinct use of these two habitats. Conclusions: It is anticipated that these results will benefit the further development of management and conservation strategies

How islands stir and fertilize the upper ocean

2000 FLORIDA AVE NW, WASHINGTON, USA, DC, 2000

Microscale patchiness of virioplankton

The microscale spatial distributions of viruses were investigated in three contrasting environments including oligotrophic open ocean, eutrophic coastal and estuarine habitats. The abundances of two discrete populations of both viruses and heterotrophic bacteria were measured at spatial resolutions of between 1 and 5 cm using purpose-designed microscale sampling equipment and flow cytometric sample analysis. Within open water samples, virus distributions were characterized by non-normal distributions and by 'hotspots' in abundance where concentrations varied by up to 17-fold. In contrast to patterns generally observed at larger spatiotemporal scales, there was no correlation between bacterial and viral abundance or correspondence between bacteria and virus hotspots within these samples. Consequently, strong hotspots and gradients in the virus:bacteria ratio (VBR) were also apparent within samples. Within vertical profiles taken from above the sediment-water interface within a temperate mangrove estuary, distributions of planktonic viruses were characterized by gradients in abundance, with highest concentrations observed within the 1-2 cm immediately above the sediment surface, and virus distributions were correlated to bacterial abundance (P<0.01). The patterns observed in these contrasting habitats indicate that microscale patchiness of virus abundance may be a common feature of the marine environment. This form of heterogeneity may have important implications for virus-host dynamics and subsequently influence microbial trophodynamics and nutrient cycling in the ocean

From random walk to multifractal random walk in zooplankton swimming behaviour

EDITORIAL OFFICE, TAIPEI, TAIWAN, 11

The impact of turbulence and phytoplankton dynamics on foam formation, seawater viscosity and chlorophyll concentration in the eastern English Channel

The space-time dynamics of chlorophyll a concentration and seawater excess viscosity has been investigated in the hydrographically contrasting inshore and offshore water masses of the eastern English Channel. This was done during the phytoplankton spring bloom dominated by Phaeocystis globosa before and after the very large-scale formation of foam induced by an increase in wind-driven turbulence and the related wave breakings. The results suggest that the dynamics of chlorophyll a concentration and seawater excess viscosity are differentially controlled by the formation of foam through the intensity of the spring bloom and wind-generated turbulence

小型クロロフィル・濁度計の空間解像度について

アレック電子株式会社東京水産大学海洋環境学科東京水産大学海洋環境学