The determination of fresh organic carbon weight from formaldehyde preserved macrofaunal samples

Methodologies are presented whereby the fresh organic carbon weight of formaldehyde preserved macrofaunal samples may be estimated. Length-organic carbon weight regressions were determined for the four numerically dominant bivalves in Narragansett Bay, Rhode Island (Nucula annulata, Yoldia limatula, Mulinia lateralis, and Pandora gouldiana) and one commercially important, but less abundant species (Mercenaria mercenaria). Constants were determined to convert the dry weight of preserved softbodied organisms (polychaetes, oligochaetes, amphipods, etc.) to fresh (unpreserved) organic carbon weight. These results can be used by investigators studying the energetics of benthic communities similar to those in Narragansett Bay.     

基于遥感分析的锦州湾海域填海造地变化

利用Landsat TM和高精度ALOS影像数据,在比较不同水体指数提取海域面积精度的基础上,利用改进的归一化差异水体指数(MNDWI),研究了1988、1995和2006年锦州湾海域填海造地情况.结果表明:1988-2006年间,锦州湾海域填海造地面积达23.63 km2,其中,12.38 km2被用作开发区建设,5.48 km2用于工业用地,3.47 km2用于码头建设,1.37 km2被用作养殖用地,0.93 km2被用为滨海浴场.大面积填海造地反映了锦州湾沿海城市建设和经济发展对土地的强烈需求,同时也必然会对该区域的生态环境造成较大影响,需要进一步加强监测和评价.     

A life history model for the San Francisco Estuary population of the Chinese mitten crab, <Emphasis Type="Italic">Eriocheir sinensis</Emphasis> (Decapoda: Grapsoidea)

First discovered in San Francisco Bay in 1992, the Chinese mitten crab,Eriocheir sinensis, has become established over hundreds of km² of the San Francisco Estuary. Ecological and economic impacts of this invasive species motivated our search for a greater understanding of the crabs life history as an important step in better management and control. Data for this life history model comes from the authors research and scientific literature. Juvenile crabs migrate from the Estuary into fresh water where they develop into adults. Environmental signals may stimulate gonad development that is followed by a downstream migration beginning at the end of summer. Mating occurs after the crabs reach saline water. Embryos are carried until hatching, and the larvae undergo five zoeal stages before settlement. Our model projects rates of development at various temperatures and growth increments, supports a minimum of 2 years in low salinity or freshwater habitat, and predicts that most California mitten crabs are at least 3 years old before becoming sexually mature. Environmental factors strongly influence the timing and duration of the crabs life stages, and are discussed in the context of a gradient of development times for worldwide populations of this important invasive species.     

Age, distribution and abundance of viable resting eggs of Acartia pacifica (Copepoda: Calanoida) in Xiamen Bay, China

The distribution and abundance of viable resting eggs of copepod Acartia pacifica in Xiamen Bay, China, were determined in the laboratory by the presence of nauplii hatched from the sediments. Sediment cores to a depth of 30 cm, sliced at 1.0 cm intervals, showed that most viable resting eggs of A. pacifica occurred near the sediment surface (0-5 cm), and the number of viable eggs sharply decreased with depth of the sediment, although resting eggs remained viable as deep as 23 cm. ²¹⁰Pb analyses of the sediments indicated that the maximum age of viable eggs of A. pacifica was 20.5 years and the mean egg age was 4.3 years. The egg mortality of A. pacifica in the sediment was 0.1408 year⁻¹, or 85.92% annual egg survival, calculated by regressing ln(egg density) on the age of the sediment. The horizontal distribution of viable resting eggs ranged from 2.27×10³ to 3.85×10⁵ m⁻², with a mean value of 9.49×10⁴ m⁻². Regressions between viable eggs of A. pacifica and all fine-fraction particle size classes (at 2 μm intervals) were not significant. The accumulation of viable resting eggs that can persist for an extended period of time provided evidence for the existence of an egg bank of A. pacifica in the seabed of Xiamen Bay.     

Nutrient release rates from the sediments of Saginaw Bay,Lake Huron

Direct measurements of net production rates and pore water profiles of solutes in the fine-grained sediments of Saginaw Bay, imply corresponding steady-state fluxes to the overlying water of 1.1–1.3 (I), 450–1010 (NH₄ ⁺), 1250–2650 (Si(OH)₄), 3000–3400 (Ca²⁺), 440–1330 (Mg²⁺), 1.5–728 (Fe²⁺), and 179–281 (Mn²⁺) moles/m²/day and 11.0–11.8 (alkalinity) meq/m²/day at 17.5 °C. Silica production rates in sediments apparently follow first order kinetics with a rate coefficient of 0.09/day and a steady-state silica concentration of 1.2 mM at 23.5°C. The remaining solutes follow kinetics approximately independent of solute concentration over the range of concentrations observed. Measured solute production rates are consistent with observed solute profiles only if lateral diffusion gradients are maintained in the sediments by the burrowing and irrigation activity of benthic organisms such asChironomous, the dominant burrower in Saginaw Bay. Assuming that solute fluxes from Saginaw Bay are representative of all of the post-glacial sediments of Lake Huron, the iodine flux from sediments is comparable to the total fluvial input of iodine. The extrapolated silica fluxes from Lake Huron sediments balance the estimated biogenic silica flux to the sediments.     

莱州湾三疣梭子蟹的生物学特征、时空分布及环境因子的影响

根据2011年5月—2012年4月进行的9个航次(月份)的底拖网调查,研究了莱州湾水域三疣梭子蟹的生物学特征、数量分布以及环境因子的影响.结果表明: 莱州湾三疣梭子蟹生物量密度的月间排序为9月>10月>7月>8月>6月>11月>3月>5月>4月.其中1龄以下个体占绝对优势,2011年7—10月4个航次所占比例平均值为86.1%.9个航次中,三疣梭子蟹的体质量、头胸甲宽及头胸甲长的平均值均以8月最高、4月最低.7—11月,雌、雄个体肥满度均以8月最高,分别为1.030和1.023,7月最低,雌雄均为1.007;雌雄个体肥满度的性别差异不显著.除6—8月外,其他月份性比(雌/雄)均小于1.0.莱州湾三疣梭子蟹5—7月主要集中在黄河口、龙口近岸,8—9月以潍坊及龙口近海密度最高,11月至翌年4月主要集中在湾口深水区.Pearson相关分析表明,莱州湾三疣梭子蟹数量分布与表层水温、溶解氧和水深的相关性最高,其次为盐度和浮游动物密度,与浮游植物密度及其他底层渔业生物个体数的相关性最低.与1981年同期对比,2011年莱州湾三疣梭子蟹的头胸甲长显著降低.建议适当降低捕捞强度,提高捕捞规格,进一步加强三疣梭子蟹增殖基础的研究,提出更加合理的增殖放流数量,以利于三疣梭子蟹资源的可持续利用.     

Movements of beluga whales (Delphinapterus leucas) in Bristol Bay,Alaska

We describe the annual distribution of beluga whales (Delphinapterus leucas) in Bristol Bay, Alaska, using data from 31 satellite‐linked transmitters during 2002–2011. Bristol Bay has one of the largest and best studied Pacific salmon (Oncorhynchus spp.) fisheries in the world, allowing us to link the seasonal distribution of belugas to that of salmon. During salmon migrations, beluga movements were restricted to river entrances. Belugas generally did not relocate to different river entrances or change bays during peak salmon periods. However, the location of belugas was not related to the number of salmon passing counting towers, suggesting that belugas were either selecting locations that were good for catching salmon or there were simply more salmon than belugas needed to supply their nutritional needs. The distribution of belugas expanded after salmon runs ended, and was greatest in winter when belugas ranged beyond the inner bays, traveling as far west as Cape Constantine. Belugas continued to frequent the inner bays in winter whenever sea ice conditions allowed, e.g., when winds moved sea ice offshore; however, they were never located south of the southern ice edge in open water or outside of Bristol Bay.     

The “Grey Area” in the Northern Bay of Bengal: A Note on a Functional Cooperative Solution

The judgments in maritime delimitation cases involving Bangladesh and Myanmar (2012) and between Bangladesh and India (2014) have resulted in a “Grey Area” in the northern Bay of Bengal involving intersecting and overlapping rights and responsibilities in terms of the exclusive economic zone (EEZ) and continental shelf regimes. This article seeks to identify a functional solution for this Grey Area.     

First record of the dynamics of domoic acid producing Pseudo-nitzschia spp. in Indonesian waters as a function of environmental variability

Within the past few decades, harmful algal blooms (HABs) have occurred frequently in Indonesian waters, resulting in environmental degradation, economic loss and human health problems. So far, HAB related studies mainly addressed ecological traits and species distribution, yet toxin measurements were virtually absent for Indonesian waters. The aim of the present study was to explore variability of the potentially toxic marine diatom genus Pseudo-nitzschia, as well as its neurotoxin domoic acid as a function of environmental conditions in Ambon Bay, eastern Indonesia. Weekly phytoplankton samples, oceanographic (CTD, nutrients) and meteorological (precipitation, wind) parameters were analyzed at 5 stations in the bay during the dry and wet seasons of 2018. Liquid chromatography – tandem mass spectrometry (LC–MS/MS) was used to detect particulate DA (pDA). Vegetative cells of Pseudo-nitzschia spp. and pDA were found in 98.6% and 51.4% of the samples, respectively. pDA levels were low, yet detected throughout the campaign, implying that Ambon Bay might potentially be subject to amnesic shellfish poisoning. The highest levels of both Pseudo-nitzschia spp. cell abundance and pDA were found in the wet season, showing a strong positive correlation between both parameters, compared to the dry season, (r = 0.87 and r = 0.66 (p < 0.01), respectively). Statistical analyses revealed that temperature and mixed layer depth positively correlated with Pseudo-nitzschia spp. and pDA during the dry season, while ammonium showed positive correlations in both seasons. This study represents the first successful investigation of the presence and variability of Pseudo-nitzschia spp. and its neurotoxin DA in Indonesian waters.