Sind südliche Arten in Nord- und Ostsee auf dem Vormarsch?

The long and warm summer 2003 resulted in water temperatures of about 2°C above the average. This promoted the immigration of southern species like the Anchovy, the Sardine, the Red Mullet and different Squid species. The possible conclusions of such invasions concerning the ordinary species of the area are rather contradictory: For the Western Baltic a positive correlation between the occurrence of Anchovy and a good Cod year-class is shown. For the southern North Sea, stomach investigations of Squid make a negative effect on fish eggs and larvae more likely.

The El Nino of 1972-1973 in the Eastern Tropical Pacific Ocean

ENGLISH: Beginning in February 1972 the usual seasonal cooling of the surface water of the eastern Pacific Ocean in the region of the Peru Current and along the equator failed to develop. By July tropical coastal and equatorial island stations and ships crossing the equator were recording sea-surface temperatures which were 6° to 8°F (3.3°-4.4°C) above the long-term mean. The anomalies spread over most of the eastern tropical Pacific and westward into the central equatorial Pacific through September. During October surface temperatures at coastal stations along South America were returning to normal, but in November and December 1972 temperatures rose rapidly again, with a near-record temperature anomaly of 8.1°F (4.2°C) above the long-term mean recorded at Puerto Chieama, Peru (7°42'S-79°27'W). After January 1973 sea-surface temperatures began returning to normal over most of the eastern tropical Pacific, and by March 1973 the El Nino had completed its cycle. Monthly sea-surface temperature anomalies over the eastern tropical Pacific are discussed to show the extent and magnitude of warming. Annual temperature profiles at several South American coastal and equatorial island stations are compared with temperature profiles for the 1957-1958 and 1965 EI Nino years. Characteristics of the temperature anomaly profiles at Puerto Chicama during several very warm years for the 1925-1972 period are also compared. Finally, meteorological factors contributing to a relaxation of the southeast trade winds and to the decreased unwilling along the coast of South America in 1972-1973 are examined. SPANISH: A comienzos de febrero de 1972, no se registró el enfriamiento común estacional del agua superficial del Océano Pacífico oriental en la región de la Corriente del Perú y a lo largo del ecuador. En julio las estaciones tropicales, costeras y de las islas ecuatoriales, y los barcos que cruzaban la linea ecuatorial registraron temperaturas superficiales del mar de 6° a 8°F (3.3°-4.4°C) más altas que la media a largo plazo. Las anomalías se esparcieron sobre la mayoría del Pacífico oriental tropical, y al oeste en el Pacífico central ecuatorial. En octubre, las temperaturas superficiales de las estaciones costaneras a lo largo de Sudamérica volvieron a la normalidad, pero en noviembre y diciembre de 1972, las temperaturas de nuevo ascendieron rápidamente con una anomalía de temperatura que alcanzó 8.1°F (4.2°C) sobre la media a largo plazo registrada en Puerto Chicama, Perú (7°42'S-79°27'W). Después de enero 1973 las temperaturas de la superficie del mar volvieron rápidamente a la normalidad en la mayoría del Pacífico oriental tropical y en marzo de 1973 el Niño había completado su ciclo. Se discuten las anomalías mensuales de las temperaturas de la superficie del mar en el Pacífico oriental tropical para indicar la extensión y magnitud del calentamiento. Los perfiles anuales de temperatura en varias estaciones costeras y de las islas ecuatoriales sudamericanas se comparan con los perfiles de temperatura de los años en que ocurrió el Niño en 1957-1958 y 1965. Se comparan también las características de los perfiles de las anomalías de temperatura en Puerto Chicama durante varios años muy cálidos para el período de 1925-1972. Finalmente, se examinan los factores meteorológicos que contribuyen al debilitamiento de los vientos alisios del sudeste y a la reducción del afloramiento a lo largo de la costa sudamericana en 1972-1973. (PDF contains 48 pages.)

Utilization of agro-industrial wastes as fish feedstuffs in Nigeria

Fish feeding accounts for a substantial amount in the variable expenditure of a fish farming enterprises. There is a need to examine closely the potentials and advantages of locally available agro-industrial by-products, as possible substitutes for the conventional feedstuffs which are dwindling in supply, and escalating in their cost. A wide range of by products from plant, animal and industrial processes have been studied and posses nutrient composition which can be exploited as dietary ingredients for warm water species as the Tilapia and Clarias sp. Such useful by-products include poultry feathers, rice bran, soybean hulls and cocoa husks which are discarded as wastes. However, some processing treatments might be required to alleviate the toxic effects of possible anti-nutritional factors in the by-products, for the achievement of optimum benefit

Panama City Fisheries Resources Office: FY 2002 Annual Report

HIGHLIGHTS FOR FY 2002 1. United States Senator Bob Graham assisted with a Gulf sturgeon survey. 2. Completed 3-year Gulf sturgeon population study in the Choctawhatchee River drainage. 3. Completed Gulf sturgeon potential spawning habitat survey for Northwest Florida and Southeast Alabama river systems. 4. Initiated Gulf sturgeon marine habitat and food resources study. 5. Completed Gulf sturgeon sentinel fish study. 6. Coordinated and conducted tagging of over 110,000 Phase II striped bass at Welaka and Warm Springs National Fish Hatchery. 7. Completed Okefenokee National Wildlife Refuge fishery sampling. 8. Developed a manuscript regarding the fishery of Banks Lake NWR. 9. Initiated development of a fish Index of Biotic Integrity for Florida panhandle streams. 10. Coordinated Okaloosa darter workshop. 11. Continued examining insect communities on Eglin AFB. 12. Sponsored and coordinated stream restoration workshop. 13. Provided technical assistance via Partners for Fish and Wildlife for stream restoration within the Northeast Gulf Ecosystem. 14. Finalized regional curve development in the Northern Region of Florida and secured significant funds for FY03 to expand to other regions in Florida. 15. Initiated freshwater mussel conservation in the Northeastern Gulf Ecosystem.

Das Klima um Grönland - 1996

Based on air temperature data from three sites of West and East Greenland, on ice charts for the area 54°N, 71°N and 20°W, 70°W, and on CTD profile observations around Greenland, the annual variability of climate is shown. Mean monthly air temperature data from Nuuk/West Greenland reveal the long-term interannual changes of air temperature anomalies. The warming trend which was observed during November, December 1995 was maintained into 1996 for about five months. Thus, spring warming of the near surface water layers, especially on the shallow bank areas off West Greenland has been favoured. As a result of mild air temperatures over most of 1996, sea ice conditions were about normal around Greenland and off eastern Canada. Subsurface observations indicate considerable warming of the 0-200 m water layer off West Greenland. The thermal anomaly of this layer amounts to +1.59K, which is the second highest value on record since the warm 1964 event. The warmer than normal conditions as recorded since November 1995 off East and West Greenland, point at intermediate warming which is characteristic of the second half of the recent decades. The long-term trend of air temperature anomalies off West Greenland points, however, still at cooling, a trend which is persistent since the early 1970s. As the potential driving mechanism for the intermediate warming in the Labrador Sea area, the sea level air pressure gradient between Iceland and the Azores is identified. The 1996 value of this gradient, the North Atlantic Oscillation (NAO) Index, is strongly negative and this represents the flow of mild air masses from the midlatitude Atlantic Ocean to the Greenland/Labrador Sea region. Accordingly, air temperature anomalies indicated unusual warming during the month of February which amounted to >2K in the region of Baffin Land, Labrador and Greenland.

Aerosol-cloud-precipitation interactions in marine stratocumulus clouds

Marine stratocumulus clouds are generally optically thick and shallow, exerting a net cooling influence on climate. Changes in atmospheric aerosol levels alter cloud microphysics (e.g., droplet size) and cloud macrophysics (e.g., liquid water path, cloud thickness), thereby affecting cloud albedo and Earth’s radiative balance. To understand the aerosol-cloud-precipitation interactions and to explore the dynamical effects, three-dimensional large-eddy simulations (LES) with detailed bin-resolved microphysics are performed to explore the diurnal variation of marine stratocumulus clouds under different aerosol levels and environmental conditions. It is shown that the marine stratocumulus cloud albedo is sensitive to aerosol perturbation under clean background conditions, and to environmental conditions such as large-scale divergence rate and free tropospheric humidity.

Based on the in-situ Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE) during Jul. and Aug. 2011, and A-Train satellite observation of 589 individual ship tracks during Jun. 2006-Dec. 2009, an analysis of cloud albedo responses in ship tracks is presented. It is found that the albedo response in ship tracks depends on the mesoscale cloud structure, the free tropospheric humidity, and cloud top height. Under closed cell structure (i.e., cloud cells ringed by a perimeter of clear air), with sufficiently dry air above cloud tops and/or higher cloud top heights, the cloud albedo can become lower in ship tracks. Based on the satellite data, nearly 25% of ship tracks exhibited a decreased albedo. The cloud macrophysical responses are crucial in determining both the strength and the sign of the cloud albedo response to aerosols.

To understand the aerosol indirect effects on global marine warm clouds, multisensory satellite observations, including CloudSat, MODIS, CALIPSO, AMSR-E, ECMWF, CERES, and NCEP, have been applied to study the sensitivity of cloud properties to aerosol levels and to large scale environmental conditions. With an estimate of anthropogenic aerosol fraction, the global aerosol indirect radiative forcing has been assessed.

As the coupling among aerosol, cloud, precipitation, and meteorological conditions in the marine boundary layer is complex, the integration of LES modeling, in-situ aircraft measurements, and global multisensory satellite data analyses improves our understanding of this complex system.

El clima de aula. Un factor decisivo en el aprendizaje de lenguas

[spa] Se ha propuesto una guía didáctica para realizar en sesiones de euskera que profundice en el conocimiento mutuo entre los alumnos para que se fomente así la creación de vinculos interpersonales basados en el diálogo, la negociación y la comprensión. Todo ello supone la generación de un ambiente de aula cálido en el que todos los alumnos (gitanos y no gitanos) se sientan respetados, reconocidos y valorados, lo que garantiza el desarrollo óptimo y el acercamiento de los alumnos a la segunda lengua

Ion acceleration with mixed solid targets interacting with circularly polarized lasers

The interaction of a circularly polarized laser pulse with a mixed solid target containing two species of ions is studied by particle in cell simulations and analytical model. After the interaction tends to be stable, it is demonstrated that the acceleration is more efficient for the heavier ions than that in plasmas containing a single kind of heavy ion and the acceleration efficiency is higher when its proportion is lower. To obtain monoenergetic heavy-ion beams, a sandwich target with a thin mixed ion layer between two light ion layers and a microstructured target are proposed. The influences of parameters of the laser pulse and target on ion acceleration are discussed in detail. It is found that, when the target is thick enough, a cold target is more appropriate for heavy-ion acceleration than a warm target, and the velocity of the reflected heavy ions is proportional to the laser amplitude.

Keine Erholung der westgrönländischen Grundfischbestände

Since 1991, the aggregate biomass of fish stocks inhabiting the West Greenland shelf stagnates at the lowest level. The latest survey results of cruise no. 152 conducted by FRV 'Walther Herwig III' do not indicate any improvements in state of the stocks, although no fishing effort was recently directed towards groundfish. The cod stock showed again a record low and is presently dominated by recruits of the year classes 1991 and 1993. Both year classes are considered to be weak and the cod stock is beyond the 'minimum biologically acceptable level'. Consequently, an increase in stock abundance is not expected either in short or long term. Other ecologically or economically important fish species, American plaice, redfish, wolffish and starry skate, were also found to have minimum stock abundances. By-catch estimates of juvenile groundfish taken by the shrimp fishery, operating at traditional grounds of cod and redfish fisheries, are indispensible. Analysis of climatological data from Nuuk/West Greenland indicates that climate during the past fourty years was characterized by two decades of anomalous warm conditions, and cooling which dominates the dimate since 1969. Anomalous cold events were encountered during 1983, 1984 and during 1992, 1993. Similar to the air temperature anomalies, autumn temperatures of the ocean surface layer indicate cold and warm periods during the past thirty years. In contrast to the colder than normal atmospheric conditions during the early nineties, however, the ocean conditions indicate intermediate warming.

Understanding planet formation through high precision photometry and spectroscopy

From studies of protoplanetary disks to extrasolar planets and planetary debris, we aim to understand the full evolution of a planetary system. Observational constraints from ground- and space-based instrumentation allows us to measure the properties of objects near and far and are central to developing this understanding. We present here three observational campaigns that, when combined with theoretical models, reveal characteristics of different stages and remnants of planet formation. The Kuiper Belt provides evidence of chemical and dynamical activity that reveals clues to its primordial environment and subsequent evolution. Large samples of this population can only be assembled at optical wavelengths, with thermal measurements at infrared and sub-mm wavelengths currently available for only the largest and closest bodies. We measure the size and shape of one particular object precisely here, in hopes of better understanding its unique dynamical history and layered composition.

Molecular organic chemistry is one of the most fundamental and widespread facets of the universe, and plays a key role in planet formation. A host of carbon-containing molecules vibrationally emit in the near-infrared when excited by warm gas, T~1000 K. The NIRSPEC instrument at the W.M. Keck Observatory is uniquely configured to study large ranges of this wavelength region at high spectral resolution. Using this facility we present studies of warm CO gas in protoplanetary disks, with a new code for precise excitation modeling. A parameterized suite of models demonstrates the abilities of the code and matches observational constraints such as line strength and shape. We use the models to probe various disk parameters as well, which are easily extensible to others with known disk emission spectra such as water, carbon dioxide, acetylene, and hydrogen cyanide.

Lastly, the existence of molecules in extrasolar planets can also be studied with NIRSPEC and reveals a great deal about the evolution of the protoplanetary gas. The species we observe in protoplanetary disks are also often present in exoplanet atmospheres, and are abundant in Earth's atmosphere as well. Thus, a sophisticated telluric removal code is necessary to analyze these high dynamic range, high-resolution spectra. We present observations of a hot Jupiter, revealing water in its atmosphere and demonstrating a new technique for exoplanet mass determination and atmospheric characterization. We will also be applying this atmospheric removal code to the aforementioned disk observations, to improve our data analysis and probe less abundant species. Guiding models using observations is the only way to develop an accurate understanding of the timescales and processes involved. The futures of the modeling and of the observations are bright, and the end goal of realizing a unified model of planet formation will require both theory and data, from a diverse collection of sources.

Temperature, organic matter and the sustainability of aquatic systems

Changes in sustainability of aquatic ecosystems are likely to be brought about by the global warming that has been widely predicted. In this article, the effects of water temperature on water-bodies (lakes, oceans and rivers) are reviewed followed by the effects of temperature on aquatic organisms. Almost all aquatic organisms require exogenous heat before they can metabolise efficiently. An organism that is adapted to warm temperatures will have a higher rate of metabolism of food organisms and this increases feeding rate. In addition, an increase in temperature raises the metabolism of food organisms, so food quality can be altered. Where populations have a different tolerance to temperature the result is habitat partitioning. One effect of prolonged high temperature is that it causes water to evaporate readily. In the marine littoral this is not an important problem as tides will replenish water in pools. Small rain pools are found in many tropical countries during the rainy season and these become incompletely dried at intervals. The biota of such pools must have resistant stages within the life cycle that enable them to cope with periods of drying. The most important potential effects of global warming include (i) the alteration of existing coastlines, (ii) the development of more deserts on some land masses, (iii) higher productivity producing higher crop production but a greater threat of algal blooms and (iv) the processing of organic matter at surface microlayers.

The lakes of Michoacan (Mexico): A brief history and alternative point of view

This article is intended to open a discussion about the historical development of lakes Zirahuen, Patzcuaro and Cuitzeo in the state of Michoacan, and the postulated relationships between lake ecology and evolution. Dr Fernando De Buen was the first man dedicated to limnology in Mexico who came to the country in the 1930s. He was adviser at the Estacion Limnologica de Patzcuaro and wrote outstanding papers dealing with Mexican lakes. The lakes of Michoacan probably formed in the late Pliocene or Holocene, and were part of a tributary to the Lerma River, which became isolated by successive volanic barriers to form lake basins. Lake Zirahuen is a warm monomictic waterbody with unique water dynamics amongst the Michoacan lakes. Because it is relatively deep (max depth 40m), seasonal patterns of alternating circulation and thermal stratification develop in the lake, a feature not shared by the other two polymictic shallow lakes, Patzcuaro and Cuitzeo.

I. Foehn winds of southern California. II. Foehn wind cyclo-genesis. III. Weather conditions associated with the Akron disaster. IV. The Los Angeles storm of December 30, 1933 to January 1, 1934

I. Foehn winds of southern California.
An investigation of the hot, dry and dust laden winds occurring in the late fall and early winter in the Los Angeles Basin and attributed in the past to the influences of the desert regions to the north revealed that these currents were of a foehn nature. Their properties were found to be entirely due to dynamical heating produced in the descent from the high level areas in the interior to the lower Los Angeles Basin. Any dust associated with the phenomenon was found to be acquired from the Los Angeles area rather than transported from the desert. It was found that the frequency of occurrence of a mild type foehn of this nature during this season was sufficient to warrant its classification as a winter monsoon. This results from the topography of the Los Angeles region which allows an easy entrance to the air from the interior by virtue of the low level mountain passes north of the area. This monsoon provides the mild winter climate of southern California since temperatures associated with the foehn currents are far higher than those experienced when maritime air from the adjacent Pacific Ocean occupies the region.

II. Foehn wind cyclo-genesis.
Intense anticyclones frequently build up over the high level regions of the Great Basin and Columbia Plateau which lie between the Sierra Nevada and Cascade Mountains to the west and the Rocky Mountains to the east. The outflow from these anticyclones produce extensive foehns east of the Rockies in the comparatively low level areas of the middle west and the Canadian provinces of Alberta and Saskatchewan. Normally at this season of the year very cold polar continental air masses are present over this territory and with the occurrence of these foehns marked discontinuity surfaces arise between the warm foehn current, which is obliged to slide over a colder mass, and the Pc air to the east. Cyclones are easily produced from this phenomenon and take the form of unstable waves which propagate along the discontinuity surface between the two dissimilar masses. A continual series of such cyclones was found to occur as long as the Great Basin anticyclone is maintained with undiminished intensity.

III. Weather conditions associated with the Akron disaster.
This situation illustrates the speedy development and propagation of young disturbances in the eastern United States during the spring of the year under the influence of the conditionally unstable tropical maritime air masses which characterise the region. It also furnishes an excellent example of the superiority of air mass and frontal methods of weather prediction for aircraft operation over the older methods based upon pressure distribution.

IV. The Los Angeles storm of December 30, 1933 to January 1, 1934.
This discussion points out some of the fundamental interactions occurring between air masses of the North Pacific Ocean in connection with Pacific Coast storms and the value of topographic and aerological considerations in predicting them. Estimates of rainfall intensity and duration from analyses of this type may be made and would prove very valuable in the Los Angeles area in connection with flood control problems.

Freshwater crabs in Africa

Freshwater crabs are a strangely neglected component of the world's inland aquatic ecosystems. Despite their wide distribution throughout the tropical and warm temperate zones of the world, and their great diversity, their role in the ecology of freshwaters is very poorly understood. This is nowhere more true than in Africa, where crabs occur in almost every freshwater system, yet even fundamentals such as their higher taxonomy are yet to be determined. This review will attempt to stimulate interest in this fascinating group of organisms by summarising what little we do know about freshwater crabs in Africa. The author describes habitat, reproduction, diet, population density, terrestrial activity and economical importance of African freshwater crabs. The article concludes with an assessment of threats and conservation. In an appendix the author describes the five families of freshwater crabs which are recognised in Africa.

Temporal and spatial variations in the quality of water in El Gergal Reservior, Seville, Spain

It is often difficult to define ‘water quality’ with any degree of precision. One approach is that suggested by Battarbee (1997) and is based on the extent to which individual lakes have changed compared with their natural ‘baseline’ status. Defining the base-line status of artificial lakes and reservoirs however, is, very difficult. In ecological terms, the definition of quality must include some consideration of their functional characteristics and the extent to which these characteristics are self-sustaining. The challenge of managing lakes in a sustainable way is particularly acute in semi-arid, Mediterranean countries. Here the quality of the water is strongly influenced by the unpredictability of the rainfall as well as year-to-year variations in the seasonal averages. Wise management requires profound knowledge of how these systems function. Thus a holistic approach must be adopted and the factors influencing the seasonal dynamics of the lakes quantified over a range of spatial and temporal scales. In this article, the authors describe some of the ways in which both long-term and short-term changes in the weather have influenced the seasonal and spatial dynamics of phytoplankton in El Gergal, a water supply reservoir situated in the south of Spain. The quality of the water stored in this reservoir is typically very good but surface blooms of algae commonly appear during warm, calm periods when the water level is low. El Gergal reservoir is managed by the Empresa Municipal de Abastecimiento y Saneamiento (EMASESA) and supplies water for domestic, commercial and industrial use to an area which includes the city of Seville and twelve of its surrounding towns (ca. 1.3 million inhabitants). El Gergal is the last of two reservoirs in a chain of four situated in the Rivera de Huelva basin, a tributary of the Guadalquivir river. It was commissioned by EMASESA in 1979 and since then the company has monitored its main limnological parameters on, at least, a monthly basis and used this information to improve the management of the reservoir. As a consequence of these intensive studies the physical, chemical and biological information acquired during this period makes the El Gergal database one of the most complete in Spain. In this article the authors focus on three ‘weather-related’ effects that have had a significant impact on the composition and distribution of phytoplankton in El Gergal: (i) the changes associated with severe droughts; (ii) the spatial variations produced by short-term changes in the weather; (iii) the impact of water transfers on the seasonal dynamics of the dinoflagellate Ceratium.