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Sawall Y.,Leibniz Center for Tropical Marine Ecology | Sawall Y.,Helmholtz Center for Ocean Research | Jompa J.,Hasanuddin University | Litaay M.,Hasanuddin University | And 2 more authors.
Marine Pollution Bulletin | Year: 2013

Coral recruitment was assessed in highly diverse and economically important Spermonde Archipelago, a reef system subjected to land-based sources of siltation/pollution and destructive fishing, over a period of 2years. Recruitment on settlement tiles reached up to 705spatm-2yr-1 and was strongest in the dry season (July-October), except off-shore, where larvae settled earlier. Pocilloporidae dominated near-shore, while a more diverse community of Acroporidae, Poritidae and others settled in the less polluted mid-shelf and off-shore reefs. Non-coral fouling community appeared to hardly influence initial coral settlement on the tiles, although, this does not necessarily infer low coral post-settlement mortality, which may be enhanced at the near- and off-shore reefs as indicated by increased abundances of potential space competitors on natural substrate. Blast fishing showed no local reduction in coral recruitment and live hard coral cover increased in oligotrophic reefs, indicating potential for coral recovery, if managed effectively. © 2013 Elsevier Ltd.

Kirillov S.A.,Arctic and Antarctic Research Institute | Dmitrenko I.A.,University of Manitoba | Holemann J.A.,Alfred Wegener Institute for Polar and Marine Research | Kassens H.,Helmholtz Center for Ocean Research | Bloshkina E.,Arctic and Antarctic Research Institute
Continental Shelf Research | Year: 2013

The large recurrent areas of open water and/or thin ice (polynyas) producing cold brine-enriched waters off the fast-ice edge are evident in the Laptev Sea in winter time. A number of abrupt positively correlated transitions in temperature and salinity were recorded in the bottom and intermediate layers at a mooring station in the West New Siberian (WNS) polynya in February-March 2008. Being in the range of ~0.5. °C and ~1.6. psu these changes are induced by horizontal motions across the polynya and correspond to temperature and salinity horizontal gradients in the range of 0.3-1.0. °C/10. km and 1.4-3.5. psu/10. km, respectively. The events of distinct freshening and temperature decrease coincide with a northward current off the fast-ice edge, while southward currents brought saltier and warmer waters at intermediate depths. We suggest that the observed transitions are connected to altering pycnocline depths across the polynya. The source of relatively fresher waters at the intermediate depths in polynya is supposed to originate from penetrative mixing of surface low salinity waters to intermediate water depth. Several forcing processes that could be responsible for a penetrative mixing through the density interface in polynya are discussed. These are penetrative convection and shear-driven mixing that originates from two-layer water dynamics and/or baroclinic tidal motions. The heavily ridged seaward fast-ice edge could produce an additional source of turbulent mixing even through a shear-free density interface due to the increased roughness at the ice-water interface. © 2013 Elsevier Ltd.

Zhan A.,CAS Research Center for Eco Environmental Sciences | Briski E.,Helmholtz Center for Ocean Research | Bock D.G.,University of British Columbia | Ghabooli S.,University of Windsor | MacIsaac H.J.,University of Windsor
Marine Biology | Year: 2015

During the past three decades, coastal marine waters have become among the most invaded habitats globally. Ascidians are among the most notorious invaders in these ecosystems. Owing to their rapid spread, frequent population outbreaks, and associated negative ecological and economic impacts, invasive ascidians have become a global problem. Thus, the study of ascidian invasions has become a prominent area of invasion biology. Here, we review current knowledge and conclude that ascidians are good models for studying invasion success in the marine realm. Firstly, we summarize the reconstruction of invasion pathways or colonization histories and associated negative impacts of invasive ascidians, and address the urgent need to clarify ambiguous taxonomy of ascidians. Secondly, we discuss factors that underlie or facilitate invasion success of ascidians, including vectors of introduction and spread, environmental changes, biological traits, and possible genetic issues. Finally, we summarize current science-based policies and management solutions that are in place to prevent and control spread of invasive ascidians. We conclude by highlighting key research questions that remain to be answered, and propose future research to investigate mechanisms of invasion success in the marine realm using ascidians as model systems. © 2015, Springer-Verlag Berlin Heidelberg.

Tang F.J.,CAS Wuhan Institute of Hydrobiology | Tang F.J.,Chinese Academy of Fishery Sciences | Tang F.J.,University of Chinese Academy of Sciences | Liu W.,Chinese Academy of Fishery Sciences | And 3 more authors.
Journal of Applied Ichthyology | Year: 2012

This paper reports the growth pattern and length-weight relationship and summarizes biological data for the clearhead icefish (Protosalanx hyalocranius) in Lake Khanka (Xingkai), on the border between China and Russia. The von Bertalanffy growth was estimated as SL=20.3(1-e -2.93 (t-0.21)). The length-weight relationship was W=0.00448 SL 2.99 for juveniles, and W=0.000896SL 3.59 for adults. P. hyalocranius mature in December and spawn in January, when the lake is still covered with ice, then die after spawning. The larvae hatch in March. Juveniles feed mainly on zooplankton whereas adults also feed on other fishes. © 2012 Blackwell Verlag, Berlin.

De Boer M.K.,University of Groningen | Moor H.,University of Stockholm | Matthiessen B.,Helmholtz Center for Ocean Research | Hillebrand H.,Carl von Ossietzky University | Eriksson B.K.,University of Groningen
Oikos | Year: 2014

Landscape connectivity can increase the capacity of communities to maintain their function when environments change by promoting the immigration of species or populations with adapted traits. However, high immigration may also restrict fine tuning of species compositions to local environmental conditions by homogenizing the community. Here we demonstrate that dispersal generates such a tradeoff between maximizing local biomass and the capacity of model periphyton metacommunities to recover after a simulated heat wave. In non-disturbed metacommunities, dispersal decreased the total biomass by preventing differentiation in species composition between the local patches making up the metacommunity. On the contrary, in metacommunities exposed to a realistic summer heat wave, dispersal promoted recovery by increasing the biomass of heat tolerant species in all local patches. Thus, the heat wave reorganized the species composition of the metacommunities and after an initial decrease in total biomass by 38.7%, dispersal fueled a full recovery of biomass in the restructured metacommunities. Although dispersal may decrease equilibrium biomass, our results highlight that connectivity is a key requirement for the response diversity that allows ecological communities to adapt to climate change through species sorting. © 2014 The Authors.

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