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41.
Effects of terrestrial runoff on the ecology of corals and coral reefs: review and synthesis 总被引：24，自引：0，他引：24
Fabricius KE 《Marine pollution bulletin》2005,50(2):125-146
This paper reviews and evaluates the current state of knowledge on the direct effects of terrestrial runoff on (1) the growth and survival of hard coral colonies, (2) coral reproduction and recruitment, and (3) organisms that interact with coral populations (coralline algae, bioeroders, macroalgae and heterotrophic filter feeders as space competitors, pathogens, and coral predators). The responses of each of these groups are evaluated separately against the four main water quality parameters: (1) increased dissolved inorganic nutrients, (2) enrichment with particulate organic matter, (3) light reduction from turbidity and (4) increased sedimentation. This separation facilitates disentangling and understanding the mechanisms leading to changes in the field, where many contaminants and many responses co-occur. The review also summarises geographic and biological factors that determine local and regional levels of resistance and resilience to degradation. It provides a conceptual aid to assess the kind of change(s) likely to occur in response to changing coastal water quality. 相似文献
42.
The cause(s) of primary outbreaks of the coral-eating crown-of-thorns starfish (Acanthaster planci) are still subject to scientific controversy. The possibility of primary outbreaks being linked to terrestrial runoff has been postulated a number of times, suggesting that enhanced nutrient supply is critical for enhanced A. planci larval development. This paper examines the evidence for such a cause, focussing particularly on the Great Barrier Reef (GBR). Nutrient discharges from rivers have increased at least four-fold in the central GBR over the last century, and concentrations of large phyto-plankton (>2 microm) of the inshore central GBR shelf in the wet season when A. planci larvae develop, is double that of other places and times. Larval development, growth and survival increase almost ten-fold with doubled concentrations of large phyto-plankton. This and other lines of evidence suggest that frequent A. planci outbreaks on the GBR may indeed be a result of increased nutrient delivery from the land. 相似文献
43.
Changes in algal, coral and fish assemblages along water quality gradients on the inshore Great Barrier Reef 总被引：11，自引：0，他引：11
Macroalgae, hard corals, octocorals, and fish were surveyed on 10 to 13 inshore coral reefs of the Great Barrier Reef, along a water quality gradient in two regions with contrasting agricultural land use. A water quality index was calculated for each reef based on available data of particulate and dissolved nutrients, chlorophyll and suspended solids. Strong gradients in ecological attributes occurred along the water quality gradient. Macroalgae of the divisions Rhodophyta and Chlorophyta increased with increasing nutrients, while Phaeophyta remained similar. Octocoral richness and abundances of many hard coral and octocoral taxa decreased, and none of the hundreds of species increased. At reefs in higher nutrient environments, hard coral and octocoral assemblages were composed of subsets of the many species found in lower nutrient environments, whereas fish and macroalgal assemblages consisted of contrasting suites of species. The study identifies species groups that are likely to increase or decrease in abundance with changing water quality. 相似文献
44.
Effects of short-term exposure to sedimentation and diuron, separately and in combination, on the photophysiology and survival of crustose coralline algae (CCA) were examined in controlled time-course experiments, using pulse-amplitude modulation (PAM) chlorophyll fluorometry. These experiments indicated that the effects of sediments and diuron, when applied in isolation, were often reversible, with recovery time dependent upon sediment type and diuron concentration. Exposure to fine (<63 microm grain size), nutrient-rich estuarine sediments reduced effective quantum yields (Delta F/F(m')) of photosystem II in CCA species more than exposure to the same amount of fine (<63 microm grain size) calcareous sediments. Significant inhibition of photosynthesis (Delta F/F(m')) was also observed at diuron concentrations > or =2.9 microg L(-1). Fine estuarine sediments in combination with 0.79 microg L(-1) dissolved diuron, caused yields (Delta F/F(m')) to drop by 60% compared with controls after 24 h. The combined exposure to sediments and diuron also retarded recovery, thus Delta F/F(m') values were still only 60% of the controls after 9 days recovery in clean seawater. Mortality of CCA was observed in some fragments treated with combinations of sediment and diuron. Our results suggest that sediment deposition and exposure to diuron can negatively affect the photosynthetic activity of CCA, with sedimentation stress being significantly enhanced by the presence of trace concentrations of diuron. 相似文献
45.
Controls on erosion patterns and sediment transport in a monsoonal,tectonically quiescent drainage,Song Gianh,central Vietnam 
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下载免费PDF全文 Tara N. Jonell Peter D. Clift Long V. Hoang Tina Hoang Andrew Carter Hella Wittmann Philipp Böning Katharina Pahnke Tammy Rittenour 《Basin Research》2017,29(Z1):659-683
The Song Gianh is a small‐sized (~3500 km2), monsoon‐dominated river in northern central Vietnam that can be used to understand how topography and climate control continental erosion. We present major element concentrations, together with Sr and Nd isotopic compositions, of siliciclastic bulk sediments to define sediment provenance and chemical weathering intensity. These data indicate preferential sediment generation in the steep, wetter upper reaches of the Song Gianh. In contrast, detrital zircon U‐Pb ages argue for significant flux from the drier, northern Rao Tro tributary. We propose that this mismatch represents disequilibrium in basin erosion patterns driven by changing monsoon strength and the onset of agriculture across the region. Detrital apatite fission track and 10Be data from modern sediment support slowing of regional bedrock exhumation rates through the Cenozoic. If the Song Gianh is representative of coastal Vietnam then the coastal mountains may have produced around 132 000–158 000 km3 of the sediment now preserved in the Song Hong‐Yinggehai Basin (17–21% of the total), the primary depocenter of the Red River. This flux does not negate the need for drainage capture in the Red River to explain the large Cenozoic sediment volumes in that basin but does partly account for the discrepancy between preserved and eroded sediment volumes. OSL ages from terraces cluster in the Early Holocene (7.4–8.5 ka), Pre‐Industrial (550–320 year BP) and in the recent past (ca. 150 year BP). The older terraces reflect high sediment production driven by a strong monsoon, whereas the younger are the product of anthropogenic impact on the landscape caused by farming. Modern river sediment is consistently more weathered than terrace sediment consistent with reworking of old weathered soils by agricultural disruption. 相似文献
46.
The nannofossils of an hydraulic piston core from the steep scarp between the St. Croix Ridge and Virgin Islands Basin were restudied. Formerly thought to represent a Pliocene debris flow, we interpret it as an early Miocene (NN1/2) hemipelagic deposit. We correlate the seismic unit sampled by piston core with the Kingshill-Jealousy Formation present on St. Croix. These sediments likely belong to an extensive, thick, deep marine cover of the St. Croix Ridge, deposited on a metamorphic—igneous basement between early Eocene and early Miocene time. Faulting did not evidently affect this sediment cover until the late Neogene. 相似文献
47.
P-T-X-controlled element transport through granulite-facies ternary feldspar from Lofoten,Norway 总被引：1，自引：1，他引：0
Katharina Hartmann Richard Wirth Gregor Markl 《Contributions to Mineralogy and Petrology》2008,156(3):359-375
Fluid transport on the grain-scale controls many rock properties and governs chemical exchange. Charnockites from Lofoten
indicate fluid penetration into ternary alkali feldspars controlled by their microtextures. In a process of fluid infiltration
at granulite-facies conditions (∼600°C and 8–11 kbar), tiny pyroxenes enclosed in alkali feldspar reacted to amphiboles, which
are always spatially connected to perthitic albite. Investigation of these microtextures by TEM imaging of Focused Ion Beam
(FIB) prepared foils revealed that pyroxenes in contact with albite lamellae show dissolution features. An amorphous Fe- and
Cl-bearing material interpreted to be a residuum of the percolating fluid was found within albite lamellae. Textures and mineral
compositions indicate that a Cl-rich aqueous fluid attacked the lamellae, which then provided pathways for further fluid flow.
A correspondence was found between feldspar compositions, their microtexture and their degree of alteration as a result of
their permeability for fluids at specific temperatures. Hence, in addition to pressure and temperature, small variations of
feldspar composition can strongly influence the fluid permeability of feldspathic rocks under lower crustal conditions. 相似文献
48.
Sandrine Mathy Patrick Criqui Katharina Knoop Manfred Fischedick Sascha Samadi 《Climate Policy》2016,16(4):S47-S62
Contrary to ‘static’ pathways that are defined once for all, this article deals with the need for policy makers to adopt a dynamic adaptive policy pathway for managing decarbonization over the period of implementation. When choosing a pathway as the most desirable option, it is important to keep in mind that each decarbonization option relies on the implementation of specific policies and instruments. Given structural, effectiveness, and timing uncertainties specific to each policy option, they may fail in delivering the expected outcomes in time. The possibility of diverging from an initial decarbonization trajectory to another one without incurring excessive costs should therefore be a strategic element in the design of an appropriate decarbonization strategy. The article relies on initial experiences in France and Germany on decarbonization planning and implementation to define elements for managing dynamic adjustment issues. Such an adaptive pathway strategy should combine long-lived incentives, like a pre-announced escalating carbon price, to form consistent expectations, as well as adaptive policies to improve overall robustness and resilience. We sketch key elements of a monitoring process based on an ex ante definition of leading indicators that should be assessed regularly and combined with signposts and trigger values at the subsector level.Policy relevanceThese research questions are of special interest and urgency following the Paris Agreement in 2015. It calls on all countries to monitor the implementation of their national contributions and review their ambition regularly. The regular revision of decarbonization pathways constitute a great research opportunity to gather experiences on decarbonization pathway implementation and on dynamic management issues to progress towards an operational dynamic adaptive policy pathway mechanism. 相似文献
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