Remarks on marine and continental biogeography: an areographical viewpoint

1994 ◽  
Vol 343 (1303) ◽  
pp. 71-78 ◽  
Keyword(s):  
Species Richness ◽  
Baltic Sea ◽  
Three Dimensional ◽  
Wide Spread ◽  
The Baltic Sea ◽  
Biogeographical Regions ◽  
The Baltic ◽  
The Way

Differences and similarities in the way marine and continental organisms occupy space are briefly reviewed. Among them, the ‘peninsula effect’ (the decline of species richness with distance from the source) is compared with the ‘bay effect’. Two cases, corals in Mochima Bay, Venezuela and fishes in the Baltic Sea, are presented as examples. The facts that the world’s oceans are larger, continuous and three-dimensional, with fewer evident geographical barriers than there are on land, explain why marine biogeographical regions are less welldefined and geographical ranges of marine taxa more wide-spread. I his generalization has, however, been questioned following recent findings of extremely rich and highly endemic benthic faunas. This problem is discussed using an index of cosmopolitanism to compare terrestrial and marine biotas.

scholarly journals An Evaluation and Implementation of the Regional Coupled Ice-Ocean Model of the Baltic Sea

2017 ◽  
Author(s):  
Jaromir Jakacki ◽  
Sebastian Meler
Keyword(s):  
Baltic Sea ◽  
Three Dimensional ◽  
Coupled Model ◽  
Horizontal Resolution ◽  
Ocean Model ◽  
System Model ◽  
The Baltic Sea ◽  
Community Earth System Model ◽  
The Baltic ◽  
Ice Model

Abstract. A three dimensional, regional coupled ice-ocean model based on the open-source Community Earth System Model has been developed and implemented for the Baltic Sea. The model consists of 66 vertical levels and has a horizontal resolution of approx. 2.3 km. The paper focuses on sea ice component results but the main changes have been introduced in the ocean part of the coupled model. The hydrodynamic part, being one of the most important components, has been also presented and validated. The ice model results were validated against the radar and satellite data, and the method of validation based on probability was introduced. In the last two decades satellite and model results show an increase in the ice extent over the whole Baltic Sea, which is an evidence of a negative trend in air temperature in recent decades and increasing of winter discharge from the catchment area.

Shallow water UAV based habitat monitoring of seagrass meadows in the Baltic Sea

2020 ◽  
Author(s):  
Felix Gross ◽  
Kilian Etter ◽  
Philipp Held ◽  
Jens Schneider von Deimling
Keyword(s):  
Baltic Sea ◽  
Three Dimensional ◽  
Marine Species ◽  
Food Sources ◽  
Storm Events ◽  
Coastal Zones ◽  
The Baltic Sea ◽  
Seagrass Meadows ◽  
Surface Models ◽  
The Baltic

<p>Seagrass meadows are crucial habitats since they serve as fish nurseries and food sources for many marine species. They prevent nearshore erosion and are an important CO<sub>2</sub> sink. As the plants are bound to the photic zone, seagrass meadows normally populate the shallow coastal zones. Unmanned aerial vehicles (UAV) are gaining popularity within the earth sciences community. Most surveys are of terrestrial nature and carried out by using the camera of the UAV to obtain orthophotos and three-dimensional surface models of a survey area. In comparison to space-borne systems, UAVs are capable of higher resolution image quality and time independent measurements, which enables an event-based surveying approach. We here present a submarine habitat mapping study, obtained by using an UAV flying 75 m above the water surface. Within the frame of the BONUS ECOMAP project, we aim to conduct repeated UAV surveys over the seasonal cycle to observe changes within coastal seagrass bed habitats. The key study area is located in the Baltic Sea offshore Heidkate (near Kiel, Germany). For data acquisition, we are using a commercial DJI Inspire 2 UAV with a gimbal mounted 20.8 megapixel Zenmuse X5S camera with a 15 mm/ 1.7 ASPH lens. For less reflection and distortion at the air-water interface, we are using a B&W circular polarized filter. Ground control points are measured and leveled with a Leica RTK system, which has a lateral resolution of ~2 cm. We process the data with the commercial software Pix4D™ and Agisoft PhotoScan™ to compute orthomosaic images and digital elevation/surface models. Since February 2018, we were able to conduct repeated surveys offshore Heidkate and Wendtorf (Germany). The average resolution of the orthomosaic data is better than 5 cm/px. First results show that we can obtain high-resolution images of habitats within water depths less than ~4 m in the Baltic Sea. Penetration is limited to factors like wave action, suspended sediment load and angle of the solar radiation. We perform supervised classification and pattern detection for habitat identification and discrimination. The data show the presence of seagrass, algae but also rocks, which are exposed at the seafloor. All scenes show a seasonal variability of the extent of seagrass meadows which are affected by migrating sand bars and major storm events. These data are the basis for a long-term monitoring framework, we are currently establishing in the working area.</p>

scholarly journals Wind of Change

2019 ◽  
Vol 28 (1) ◽  
pp. 78-84 ◽  
Author(s):  
Tanel Rander
Keyword(s):  
Baltic Sea ◽  
Collective Memory ◽  
Home Country ◽  
Local People ◽  
The Baltic Sea ◽  
The West ◽  
Nuclear Missiles ◽  
The Baltic ◽  
The Way ◽  
Led Zeppelin

What remains of the Soviet identity for those who grew up in an empire that started in the Baltic sea and ended in Kamchatka? What kind of post-Soviet cultural combos have been produced afterwards? Was it bizarre to listen to Led Zeppelin and Nirvana while being targeted with nuclear missiles from the West? In a retrospective way and engaging with the collective memory of his home country, Estonia, the author reflects on different narratives of Europeanisation, shame and peripherality and the way local people embodied them.

scholarly journals Surface morphology and backscattering of ice-ridge sails in the Baltic Sea

1996 ◽  
Vol 42 (140) ◽  
pp. 141-156 ◽  
Author(s):  
A. T. Manninen
Keyword(s):  
Baltic Sea ◽  
Incidence Angle ◽  
Slope Angle ◽  
Three Dimensional ◽  
The Baltic Sea ◽  
Geometrical Properties ◽  
Radar Images ◽  
Side Facet ◽  
The Baltic ◽  
Log Normal

AbstractThe triangular shape of an ice-ridge sail in the Baltic Sea was studied statistically. The dimensions and orientation of individual ice blocks were measured in several ridges. All measurements were carried out from the standpoint of backscattering research. The results confirm that given geometrical properties of the two sides of ice ridges are in general not equal. A slight negative correlation was found between the slope angle and width of the sail. All three orientations and all three size parameters of ice blocks on both sides of the ridges studied can be considered as normally distributed. A log-normal distribution, however, fits slightly better the dimensions of the orientationally best rectangular approximations of the polygonal main facets of flat ice blocks. Three-dimensional modelling of ice ridges is essential, since the total side-facet area visible is typically at least as large as the total main-facet area. Calculated incidence-angle distrubutions show that the broad distributions of orientations and dimensions make different redges appear very similar on radar images.

scholarly journals Species richness and functional attributes of fish assemblages across a large-scale salinity gradient in shallow coastal areas

2021 ◽  
Author(s):  
Birgit Koehler ◽  
Mårten Erlandsson ◽  
Martin Karlsson ◽  
Lena Bergström
Keyword(s):  
Species Richness ◽  
Baltic Sea ◽  
Fish Species ◽  
Large Scale ◽  
Salinity Gradient ◽  
Coastal Areas ◽  
The Baltic Sea ◽  
Salinity Regime ◽  
Functional Attributes ◽  
The Baltic

Abstract. Coastal ecosystems are biologically productive and their diversity underlies various ecosystem services to humans. However, large-scale species richness (SR) and its regulating factors remain uncertain for many organism groups, owing not least to the fact that observed SR (SRobs) is strongly dependent on sample size and inventory completeness (IC). We estimated changes in SR across a natural geographical gradient using statistical rarefaction and extrapolation methods, based on a large fish species incidence dataset compiled from Swedish fish survey databases. The data covered nearly five decades (1975–2020), a 1,300 km north-south distance and a 10-fold salinity gradient along sub-basins of the Baltic Sea plus Skagerrak. Focusing on shallow coastal and offshore areas (< 30 m depth), we calculated standardized SR (SRstd) and estimated SR (SRest), and related these to sub-basin annual mean salinity and water temperature. IC was high, 98.5 %–99.9 %, in the 10 sub-basins with sufficient data for analysis. The recorded fish species were of 75 % marine and 25 % freshwater origin. Total fish SRobs was 144 for shallow coastal areas, and 110 for shallow offshore areas. Sub-basin specific SRest for coastal areas varied between 35 ± 7 (SE) and 109 ± 6 fish species, and was ca. three times higher in the most saline (salinity 29-32) compared to the least saline sub-basins (salinity 2.7). Completing information on functional attributes showed that differences along the salinity gradient reflected an increased share of coastal resident fish species in lower salinities, and a higher share of migratory fish at higher salinities. The proportion of benthic and demersal fish species was also lower in the least saline sub-basins, and increased with increasing salinity. If climate change lowers the salinity regime of the Baltic Sea in the future this may hence influence the SR and community composition of fish.

Metazoan parasites from herring (Clupea harengus L.) as biological indicators in the Baltic Sea

2014 ◽  
Vol 59 (3) ◽  
Author(s):  
Patrick Unger ◽  
Sven Klimpel ◽  
Thomas Lang ◽  
Harry Palm
Keyword(s):  
Species Richness ◽  
Baltic Sea ◽  
Parasite Species ◽  
Distribution Patterns ◽  
Biological Indicators ◽  
Clupea Harengus ◽  
Fish Parasites ◽  
The Baltic Sea ◽  
Metazoan Parasites ◽  
The Baltic

AbstractZoographical distribution of metazoan fish parasites in herring, Clupea harengus, from the Baltic Sea was analysed in order to use them as potential biological indicators. A total of 210 herring from six different sampling sites were investigated, harbouring 12 different parasite species [five digeneans (D), one cestode (C), three nematodes (N) and three acanthocephalans (A)]. The distribution of the parasite species differed according to region, with a distinct gradient of decreasing species richness towards the east of the Baltic Sea. The western localities at Kiel Bay, Rügen and Poland had the highest parasite diversity, including the marine parasite species Anisakis simplex (s.s.) (N), Brachyphallus crenatus and Hemiurus luehei (both D). The eastern localities had low parasite species richness, predominated by the freshwater digenean Diplostomum spathaceum. We could identify three different Baltic herring stocks, the spring-spawning herring of the western Baltic reaching from the Kattegat to the German and Polish coast, the stock of the central Baltic proper and the northern stock of C. harengus var. membras of the Gulf of Finland. The limited distribution of the herring parasites within the Baltic Sea enables their use as biological indicators for migration patterns and stock separation. The acanthocephalan Pomphorhynchus laevis that has already been used as an accumulation bioindicator for heavy metals was only recorded for the western herring stocks. However, the presence of mainly generalistic parasites and their uneven distribution patterns make their use as indicators for regional environmental and global change more difficult.

Sign in / Sign up

Export Citation Format

Share Document