Indonesian Institute of Sciences

About: Indonesian Institute of Sciences is a facility organization based out in Jakarta, Indonesia. It is known for research contribution in the topics: Population & Biology. The organization has 4795 authors who have published 10544 publications receiving 76990 citations. The organization is also known as: Indonesian Institute of Sciences Cibinong, Indonesia.

Marine megaherbivore grazing may increase seagrass tolerance to high nutrient loads

Abstract: Summary 1. Populations of marine megaherbivores including green turtle (Chelonia mydas) have declined dramatically at a global scale as a result of overharvesting and habitat loss. This decline can be expected to also affect the tolerance of seagrass systems to coastal eutrophication. Until now, however, simultaneous effects of top–down control by megaherbivore grazing and bottom–up control by nutrient input have not been tested experimentally. 2. We therefore investigated the interacting effects of nutrient (N and P) addition and mimicked green turtle grazing on seagrass and epiphyte productivity, seagrass biomass and nutrient contents in exclosures at a pristine seagrass site in the Indo-Pacific region (Kalimantan, Indonesia). 3. Grazing almost doubled leaf biomass production rates, while nutrient addition (N+P, slow-release granules) did not have an effect on these rates. Rhizome biomass was, however, strongly reduced by nutrient addition. In contrast to phosphorus, tissue nitrogen contents increased after nutrient addition, showing that nitrogen was not limiting primary productivity. Epiphyte growth was, however, strongly correlated with high water column P concentrations, indicating an indirect negative effect of eutrophication when turtle grazing would be absent. We calculated that green turtle leaf grazing leads to substantial exports of N and P, at rates of at least 8% of the standing stock per day equalling the daily seagrass production, up to 13 (N) and 1.4 (P) mg m−2 day−1. 4. Synthesis. By combining our quantified effects with literature data, we propose a conceptual model of seagrass functioning under megaherbivore leaf grazing and eutrophication. In tropical seagrass systems with high green turtle grazing pressure, grazing alleviates the negative effects of eutrophication by the stimulation of seagrass production and concomitant nutrient uptake, the increased export of nutrients and the indirect prevention of low below-ground biomass. Similar to the role of terrestrial megaherbivores, these strong top–down controls show the pivotal role of green turtles in current coastal systems, which is lacking in systems where their numbers have greatly declined. These marine megaherbivores do not only drive structure and functioning of their foraging grounds but also increase the tolerance of seagrass ecosystems to eutrophication.

Long-term carbon sink in Borneo’s forests halted by drought and vulnerable to edge effects

Abstract: Less than half of anthropogenic carbon dioxide emissions remain in the atmosphere. While carbon balance models imply large carbon uptake in tropical forests, direct on-the-ground observations are still lacking in Southeast Asia. Here, using long-term plot monitoring records of up to half a century, we find that intact forests in Borneo gained 0.43 Mg C ha−1 per year (95% CI 0.14–0.72, mean period 1988–2010) above-ground live biomass. These results closely match those from African and Amazonian plot networks, suggesting that the world’s remaining intact tropical forests are now en masse out-of-equilibrium. Although both pan-tropical and long-term, the sink in remaining intact forests appears vulnerable to climate and land use changes. Across Borneo the 1997–1998 El Nino drought temporarily halted the carbon sink by increasing tree mortality, while fragmentation persistently offset the sink and turned many edge-affected forests into a carbon source to the atmosphere.

Energy dependence and fluctuations of anisotropic flow in Pb-Pb collisions at √sNN = 5.02 and 2.76 TeV

Abstract: Measurements of anisotropic flow coefficients with two- and multi-particle cumulants for inclusive charged particles in Pb-Pb collisions at $ \sqrt{s_{\mathrm{NN}}}=5.02 $ and 2.76 TeV are reported in the pseudorapidity range |η| < 0.8 and transverse momentum 0.2 < p$_{T}$ < 50 GeV/c. The full data sample collected by the ALICE detector in 2015 (2010), corresponding to an integrated luminosity of 12.7 (2.0) μb$^{−1}$ in the centrality range 0-80%, is analysed. Flow coefficients up to the sixth flow harmonic (v$_{6}$) are reported and a detailed comparison among results at the two energies is carried out. The p$_{T}$ dependence of anisotropic flow coefficients and its evolution with respect to centrality and harmonic number n are investigated. An approximate power-law scaling of the form v$_{n}$(p$_{T}$) ∼ p$_{T}^{n}^{/3}$ is observed for all flow harmonics at low p$_{T}$ (0.2 < p$_{T}$ < 3 GeV/c). At the same time, the ratios v$_{n}$/v$_{m}^{n}^{/ }^{m}$ are observed to be essentially independent of p$_{T}$ for most centralities up to about p$_{T}$ = 10 GeV/c. Analysing the differences among higher-order cumulants of elliptic flow (v$_{2}$), which have different sensitivities to flow fluctuations, a measurement of the standardised skewness of the event-by-event v$_{2}$ distribution P(v$_{2}$) is reported and constraints on its higher moments are provided. The Elliptic Power distribution is used to parametrise P(v$_{2}$), extracting its parameters from fits to cumulants. The measurements are compared to different model predictions in order to discriminate among initial-state models and to constrain the temperature dependence of the shear viscosity to entropy-density ratio.