增生地带的混杂堆积和页岩底辟作用的重要性

虽然普遍认为混杂堆积来自于俯冲带,但与那种具有特殊混杂外貌的混杂岩形成机制大不相同。对这个问题的争论,集中在刮落或底侵作用发生过程中沿内海沟斜坡的重力下滑作用和沿冲断裂产生剪切作用的效果上。尽管出露在大陆上的某些混杂沉积,虽适合于一种滑     

Does heavy oil pollution induce bacterial diseases in Japanese flounder Paralichthys olivaceus?

As basic research for the effect of heavy oil on the fish immune system, in this study, the number of leukocyte was counted in Japanese flounder Paralichthys olivaceus, after exposure to heavy oil at a concentration of 30 g/8L for 3 days. To compare the numbers of bacteria in the skin mucus between oil-exposed and control fish, viable bacteria were enumerated by counting colony forming unit (CFU). Compared with 5.79+/-1.88 x 10(7)leukocytes/mL in the controls, the exposed fish demonstrated higher counts, averaging 1.45+/-0.45 x 10(8)cells/mL. The bacterial numbers of control fish were 4.27+/-3.68 x 10(4)CFU/g, whereas they were 4.58+/-1.63 x 10(5)CFU/g in the exposed fish. The results suggest that immune suppression of the fish occurred due to heavy oil stressor, and bacteria could invade in the mucus, resulting in the increasing leukocyte number to prevent infectious disease.     

森林土壤碳、氮淋失过程及其形成机制研究进展

大气氮沉降对森林生态系统碳截存和损耗过程的影响已引起广泛关注, 但对沉降氮在森 林生态系统中的去向、增氮对土壤中碳/氮转化过程的影响以及土壤氮饱和前后土壤渗漏液中溶 解性有机碳(DOC) 和溶解性有机氮(DON) 动态等方面的研究还不够深入。本文论述了近年来国 内外在土壤氮饱和及土壤碳、氮淋溶领域的最新研究进展, 从系统论的角度阐述土壤氮饱和过程 及内涵; 通过论述DOC 和DON 含量及其结构组成变化来揭示其对增氮/氮沉降的内在响应机 理; 论述了增氮对土壤无机氮转化的影响以及生物和非生物因素对沉降氮固持的贡献。指出土壤 氮饱和为土壤中的有效氮随时间增加超过了土壤中生物和非生物的持留能力, 导致土壤氮的净 矿化、净硝化、NO₃^-流失以及土壤酸化等过程发生一系列非线性变化。初步认为土壤中DOC 和 DON 对增氮的不同响应归因于氮素饱和过程的三个不同阶段。对于特定的生态系统来说, 需要 清楚地认识土壤氮素矿化、硝化、反硝化和固持等过程, 才能明晰土壤氮素状态以及随时间的演 变。另外, 指出在上述三个研究领域中存在的问题, 并提出拟解决的途径以及未来的可能研究方 向, 以期对该领域的研究提供参考。     

Effects of nutrients on crude oil biodegradation in the upper intertidal zone

To enhance biodegradation, nutrients in the form of slow-release fertilizer (SRF) were applied to oil-contaminated microcosms (3%, v/v) which simulated intertidal environmental systems. Although nutrient concentrations in the interstitial water were not proportional to those in amended SRF, microbial activity, growth of oil-degrading microorganisms, and oil-degradation rate were closely related to the concentration of nutrients in the interstitial water. Adding nutrients at higher dose (microcosm I, 144.4 mg C/kg sand/day, versus microcosm II, 8.5 mg C/kg sand/day) had a positive effect on oil degradation rate, which was especially obvious during the early phase of treatment. Use of pristane, phytane, and nor-hopane as biomarkers enabled the detection of significant treatment differences in hydrocarbon biodegradation, which were not reliable enough when the data were normalized to sand mass.     

The most temperature-adapted corals have an Achilles' Heel

The corals of the Persian/Arabian Gulf are better adapted to temperature fluctuations than elsewhere in the Indo-Pacific. The Gulf is an extreme marine environment displaying the highest known summer water temperatures for any reef area. The small and shallow sea can be considered a good analogue to future conditions for the rest of the world’s oceans under global warming. The fact that corals can persist in such a demanding environment indicates that they have been able to acclimatize and selectively adapt to elevated temperature. The implication being that colonies elsewhere may be able to follow suit. This in turn provides hope that corals may, given sufficient time, similarly adapt to survive even in an impoverished form, under conditions of acidification-driven lowering of CaCO₃ saturation state, a further consequence of raised atmospheric CO₂. This paper demonstrates, however, that the uniquely adapted corals of the Gulf may, within the next three centuries, be threatened by a chronic habitat shortage brought about by the dissolution of the lithified seabed on which they rely for colonisation. This will occur due to modifications in the chemical composition of the Gulf waters due to climate change.     

Application of enterococci antibiotic resistance patterns for contamination source identification at Huntington Beach,California

Huntington Beach, California, one of the most popular surfing spots in the world, is plagued by sporadic, elevated levels of fecal bacteria. To assist with pollution source identification, we analyzed antibiotic resistance patterns (ARPs) of enterococci from four known sources (bird feces, urban runoff, coastal marsh sediment and sewage effluent from local sanitation district) and one unknown source (seawater) using seven antibiotics at four concentrations each. Of 2491 enterococci tested, all were resistant to at least one antibiotic at some level. Discriminant analysis indicated that the average correct classification rates for bird feces and urban runoff sources were above 80%. Sewage effluent contained mixed fecal sources. Sixty-four percent of the sewage isolates classified with the sewage category, while the other 35% of isolates were assigned evenly across the other three categories. When enterococci isolated from the seawater were classified using the known ARP database, it was evident that bird feces were the source of surf zone contamination on some days while the coastal salt marsh and sewage plume may have impacted the surf zone water quality to various degrees during other times.