Geochemistry of high arsenic groundwater in Chia-Nan plain, Southwestern Taiwan: possible sources and reactive transport of arsenic

Major ion, trace element, and stable isotope analyses were performed on groundwater samples collected during November 2005 and 2006 in Chia-Nan plain of southwestern Taiwan to examine As mobilization in aquifers. The high concentrations of As, Fe and Mn in the groundwater is consistent with low Eh values (under moderately reduced state). Moreover, the observed Na/Cl and SO(4)/Cl molar ratios in groundwater demonstrate the influence of seawater intrusion. Seawater intrusion could provide required electron acceptors (i.e., SO(4)) for bacterial sulfate reduction and promote reducing conditions that are favorable for As mobilization. The concurrent increases in the concentrations of Fe and Mn from 2005 to 2006 may be caused by bacterial Fe(III) and Mn(IV) reduction. Geochemical modeling demonstrate that As(III) is the dominant As species and the presence of Fe-bearing carbonates, sulfides, and oxide phases may locally act as potential sinks for As. Mud volcano fluids were also collected and analyzed to assess the possible source of As in the Chia-Nan plain groundwater. The oxygen and hydrogen isotopic signatures indicate that the As-rich mud volcano fluids may have been modified by chemical exchange with (18)O-rich crustal rocks and possibly originated from mixing of deep brines with circulating meteoric water. Thus As in the Chia-Nan plain groundwater may have been evolved from deep crustal fluids or rock sources. The hydrogeochemistry and widespread As enrichment in groundwater of Chia-Nan plain result from multiple processes, e.g., de-watering of deep crustal fluids, seawater intrusion, and biogeochemical cycling of Fe, As, and S in alluvial sediments.     

Multi-locus DNA fingerprinting supports genetic monogamy in Florida scrub-jays

Extensive behavioural and pedigree data on a colour-marked population of Florida scrub-jays (Aphelocoma coerulescens) suggested that this cooperatively breeding species is monogamous, with extremely rare exceptions in which males have two mates. We used multi-locus DNA fingerprinting to test these observations by determining genetic parentage. Despite restricted dispersal and high relatedness between behavioural parents and non-breeding members of the group, DNA fingerprints provided sufficient variability to determine parentage unambiguously in almost all cases. We found no evidence of extra-pair fertilisation of females or egg dumping, and confirmed a suspected case of polygyny in which a mother and daughter laid and incubated in the same nest. Our results confirm that detailed behavioural data allow accurate assignment of genetic parentage in this species. In Florida scrub-jays, large territory size may limit opportunities for cuckoldry, and persistent intense competition for limited breeding space may lead to low variance in the quality of established male breeders. These factors would reduce both the opportunity for, and benefits of engaging in extra-pair fertilisations. Delayed dispersal and cooperative breeding in this species have not evolved as avenues for direct reproduction by unpaired individuals. Received: 25 May 1998 / Accepted after revision: 26 June 1998     

应用AFLP技术对斜茎黄芪根瘤菌遗传多样性的分析研究

采用ＡＦＬＰ指纹图谱分析技术对来自我国不同地区的９５株斜茎黄芪根瘤菌及２４株已知根瘤菌的参比菌一起进行遗传多样性研究．结果表明,在５０％相似性水平上,全部菌株被分为３１个ＡＦＬＰ群,显示出极大的遗传多样性．相关性较高的菌株的聚类结果与先前的表型性状数值分析结果相一致．具相同ＡＦＬＰ指纹图谱的菌株都具有相同的生长速度,且其中大部分菌株来自我国同一地区,同时具很高的表型相似性．此外,本研究表明,ＡＦＬＰ指纹技术具更高的分辩率,更能揭示种内的遗传多样性     

利用LZF－1DNA指纹探针进行家系的父权鉴定

ＬＺＦ－１ＤＮＡ指纹探针经同位素γ－３２Ｐ－ＡＴＰ标记后，检测了４个家系１３个个体血样的ＤＮＡ指纹．结果表明，父母的遗传物质在子代中的传递符合孟德尔遗传规律，无误地确定了４个家系中的亲子血缘关系．ＬＺＦ－１ＤＮＡ指纹探针在亲权鉴定中的父权概率是０．９９９６４，达到了父权认定的目的     

The Effect of Sediment Source Changes on Pollen Records in Lake Sediments

A major focus of palynological research has been to assess the various pathways by which pollen is delivered to sedimentary archives. In open lake systems, the contribution of streamborne pollen to lake sediments is thought to be highly significant. Despite this, little research has attempted to identify changes in the pollen record that might be attributed to changing sediment pathways rather than to changes in vegetation. This research aims to partially redress this gap by examining a dated pollen sequence from Kyre Pool, Worcestershire, England. The results presented in this paper suggest that some changes in sediment source, as determined by a fingerprinting approach, can influence the pollen record reconstructed from a lake sediment profile.     

Mating frequency, colony size, polyethism and sex ratio in fungus-growing ants (Attini)

The mating frequency of queens was estimated for eight attine ant species, Myrmicocrypta ednaella, Apterostigma mayri, Cyphomyrmex costatus, C. rimosus (four lower attines), Trachymyrmex isthmicus, Serico-myrmex amabalis, Acromyrmex octospinosus and Atta colombica (four higher attines), and correlated to colony size, worker polyethism, and sex ratio. Mating frequency was calculated from within-colony relatedness estimated by CAP-PCR DNA fingerprinting. Most queens of lower attines and T. isthmicus mated with only one male, while those of the three higher attines mated with multiple males. Mating frequency was positively correlated with colony size. Polyethism among workers was dependent on worker age in lower attines but on body size in higher attines, suggesting some correlation between mating frequency (i.e., within-colony gene diversity) and caste complexity. The sex ratio was biased toward females in species where the mating frequency equaled one, but toward males in species where the mating frequency was greater than two. Changing in nest site from ground surface to deep underground may have facilitated the evolution of large colony size in Attini, and this may have resulted in the evolution of polyandry (a queen mates with multiple males). With the evolution of polyandry in higher attines, Atta and Acromyrmex in particular have generated high genetic diversity within their colonies and complex social structures. Received: 26 October 1999 / Revised: 25 May 2000 / Accepted: 24 June 2000     

Extra-pair paternity and tail ornamentation in the barn swallow Hirundo rustica

Females of socially monogamous species may copulate with attractive non-mates to obtain access to the genes of such males, and a preference for attractive copulation partners may result in sexual selection. Extra-pair copulations are common in the socially monogamous barn swallow Hirundorustica, and a 2-year study of paternity using multi-locus DNA fingerprinting demonstrated that 33% of 63 broods and 28% of 261 offspring were sired by extra-pair males. The frequency of extra-pair offspring within broods was highly skewed with the majority of all broods having either no extra-pair offspring or only extra-pair offspring. Individual pairs were consistent in their frequency of extra-pair paternity among broods, and the repeatability of extra-pair paternity of multiple broods of the same female was statistically significant. The proportion of extra-pair offspring was negatively related to the tail length of the male attending the nest. Behavioural observations showed that extra-pair fertilizations were more likely in broods raised by females that had been observed to engage in extra-pair copulations. The frequency of extra-pair offspring was unrelated to the intensity of two male paternity guards, mate guarding and the rate of intra-pair copulations. In an analysis of extra-pair paternity and male parental care in different broods of the same male, male barn swallows fed their offspring relatively less frequently if the brood contained more extra-pair offspring. Therefore, female barn swallows pursue extra-pair copulations with attractive males, which may result in sexual selection, even though extra-pair paternity is costly for females due to the reduction of paternal care by their social mates. Received: 24 January 1997 / Accepted after revision: 2 August 1997     

Biogeochemical distinction of methane releases from two Amazon hydroreservoirs

Biogeochemical distinction of methane emissions to the atmosphere may essentially rely on the surface area and morphometry of Amazon hydroreservoirs. Tucuruí (deep) and Samuel (shallow) reservoirs released in average 13.82 ± 22.94 and 71.19 ± 107.4 mg CH₄ m⁻² d⁻¹, respectively. δ¹³C–CH₄ values from the sediments to the atmosphere indicate that the deep reservoir has extended methanotrophic layer, oxidizing large quantities of light isotope methane coming from the sediments, while sediment-generated methane can easily evade the shallow reservoir.     

Female control of reproductive skew in cooperatively breeding brown jays (<Emphasis Type="Italic">Cyanocorax morio</Emphasis>)

Brown jays (Cyanocorax morio) are long-lived, social corvids that live in large, stable, territorial groups (mean = 10 individuals). In this study, I determined the distribution of reproductive success within groups using multi-locus DNA fingerprinting. Breeding females produced virtually all (99%) of the young within their own nests. Reproduction within groups was highly skewed towards a single primary female, although long term data indicate that secondary females (female breeders that were usually younger and subordinate to the primary female) were sometimes successful. The high reproductive skew observed for females was associated with primary female aggression. Successful reproduction by secondary females may have been due to parental facilitation or the inability of primary females to completely suppress secondary females. Multiple paternity occurred in 31–43% of broods and extra-group paternity occurred in a minimum of 22% of broods. Patterns of paternity also varied between years, since females often switched or included new genetic mates. Although male consorts of nesting females fathered relatively few offspring (20%), they still had a higher chance of fathering offspring than any other single group male. Reproduction was less skewed for males than females as a result of female mating patterns. Female reproductive patterns are consistent with some of the predictions and assumptions from optimal skew models, while male reproductive patterns are not. The factors affecting skew in species with complex social systems such as incomplete control by breeders over subordinate reproduction, female control of paternity, and resource inheritance have not been well incorporated into reproductive skew models.Communicated by: J. Dickinson     

同位素稀释-液相色谱-串联质谱法同时测定养殖水体中23种镇静剂

建立了同位素稀释-液相色谱-串联质谱法（LC-MS/MS）同时测定养殖水体中23种镇静剂残留的方法。样品经0.45 μm滤膜过滤后,用Oasis HLB固相萃取柱净化,浓缩后用50%的甲醇水定容。以1%甲酸水溶液和乙腈为流动相,采用Agilent InfiniityLab Poroshell 120 SB-C18色谱柱分离后,在多反应监测模式下测定,内标法定量。结果表明,23种镇静剂在0.5～100ng/L质量浓度范围内线性关系良好（r>0.99）,检出限和定量限分别为0.1~0.3和0.4 ~1.0 ng/L。加标回收率为73.5%~117.6%,相对标准偏差（RSD）为1.1%~9.9%。该方法前处理简单,净化效果较好,灵敏度较高,适用于池塘养殖水体中23种镇静剂类药物残留的快速检测。