Spatial variability of recent sedimentation in Lake Ohrid (Albania/Macedonia)

The extraordinary diversity in long-lived lakes is largely driven by distinct eco-evolutionary processes. With their unique biota and numerous endemic taxa, these lakes are key settings for fundamental studies related to ecology, diversity, and evolution. Here, we test how the environment shapes diatom diversity and community patterns over space in ancient Lake Ohrid. By applying Bray-Curtis similarity analyses of diatom community data, including widespread and endemic taxa, we identified two major zones: littoral and sublittoral. The latter one is being characterized with higher endemic diversity. The a and b diatom diversity and community distribution in the northern and eastern part of the lake are influenced by the presence of vertical (bathymetrical) and horizontal barriers. The zonation of the diatom communities appears driven by two large-scale factors: (i) water depth, and (ii) water chemistry, primarily, the concentration of total phosphorus, nitrogen ammonia, and conductivity. Both drivers appear to equally influence diatom diversity and community patterns. We present initial data on diatom-environment relations, where the results support earlier ecological studies emphasizing the relevance of ongoing human-induced eutrophication in the northern lake area. This study provides background information on the role of the environment in structuring contemporary diatom diversity. However, future research needs to focus on the biotic component including species competition in order to reveal the mechanisms driving spatial community dynamics in Lake Ohrid.

show abstract

“…Vogel et al, 2010). The sediment structure varies along the whole basin, due to the complex geodynamic setting of the lake.…”

Section: Diatom Diversity and Community Patternsmentioning

confidence: 99%

Spatial patterns of diatom diversity and community structure in ancient Lake Ohrid

et al. 2018

View full text Add to dashboard Cite

show abstract

“…During permanent deposition from the source to the bottom of the lake, sedimentary organic matter is influenced by a variety of factors including river inputs, underwater topography, and lake wind and induced waves, which eventually leads to different spatial distribution patterns [19][20][21][22][23][45][46][47]. In some small lakes, the spatial distribution of sedimentary organic matter is relatively simple, owing to one factor showing the greatest effect [48].…”

Section: Influence Factors and Paleolimnological Significancementioning

confidence: 99%

“…Therefore, it is necessary to understand the modern sedimentary processes of lakes to clarify the environmental significance of proxies [18]. Because surface sediments contain information regarding the formation, sedimentation and distribution of sediments within a lake [19][20][21][22], in this study, we used the organic matter indices of 67 surface sediments from Nam Co, the second largest lake on the Tibetan Plateau, to elucidate the spatial distribution of sediments and their sedimentary processes. This study will provide evidence for interpretation of long sediment records within the lake.…”

mentioning

confidence: 99%

The spatial distribution and sedimentary processes of organic matter in surface sediments of Nam Co, Central Tibetan Plateau

et al. 2012

View full text Add to dashboard Cite

In this study, 67 surface sediment samples collected from Nam Co in central Tibet were analyzed for total carbon, total organic carbon and total nitrogen, and 51 of these samples were also analyzed for n-alkanes. The origin and spatial distribution of organic matter were then investigated using these proxies, and the control factors responsible for the spatial distribution patterns and paleolimnological significance were discussed. The results indicated that the origin of organic matter in surface sediment of Nam Co is consistent with the sources of n-alkanes, which were primarily submerged plants, followed by terrestrial plants, and then aquatic algae and bacteria. The organic matter in surface sediments of the lake showed typical spatial variability. Because of the great influence of underwater topography, river inputs and water quality, the spatial distribution of organic matter is enriched from the source to the deposit center. This spatial variability of organic matter in the lake indicates that the sediments in different areas have different sensitivities to environmental changes, which is important to reconstruction of paleoenvironments and paleoclimate using lake sediment cores.Tibetan Plateau, Nam Co, surface sediments, spatial distribution, sedimentary processes Citation:Wang Y, Zhu L P, Wang J B, et al. The spatial distribution and sedimentary processes of organic matter in surface sediments

show abstract

“…1) in order to improve the water balance of the lake and to enhance its potential for hydropower use. Since then, however, it has been a major source of biochemical oxygen demand (BOD) and sediments fed into the lake (Jordanoski et al, 2006;Vogel et al, 2010b). Long-term microbiological as well as physico-chemical investigations revealed the adverse effects of the Sateska inflow on Lake Ohrid (Watzin et al, 2002).…”

Section: Watershed Impactsmentioning

confidence: 99%

“…2.2) and thus pose a threat to oligotrophic Lake Ohrid (e.g., Vogel et al, 2010b). Most of those rivers flow through populated areas with nonexistent or inefficient sewage treatment systems.…”

Section: Watershed Impactsmentioning

confidence: 99%

A freshwater biodiversity hotspot under pressure – assessing threats and identifying conservation needs for ancient Lake Ohrid

et al. 2010

Self Cite

View full text Add to dashboard Cite

Abstract. Immediate conservation measures for world-wide freshwater resources are of eminent importance. This is particularly true for so-called ancient lakes. While these lakes are famous for being evolutionary theatres, often displaying an extraordinarily high degree of biodiversity and endemism, in many cases these biota are also experiencing extreme anthropogenic impact. Lake Ohrid, a major European biodiversity hotspot situated in a trans-frontier setting on the Balkans, is a prime example for a lake with a magnitude of narrow range endemic taxa that are under increasing anthropogenic pressure. Unfortunately, evidence for a "creeping biodiversity crisis" has accumulated over the last decades, and major socio-political changes have gone along with human-mediated environmental changes.Based on field surveys, monitoring data, published records, and expert interviews, we aimed to (1) assess threats to Lake Ohrids' (endemic) biodiversity, (2) summarize existing conservation activities and strategies, and (3) outline future conservation needs for Lake Ohrid. We compiled threats to both specific taxa (and in cases to particular species) as well as to the lake ecosystems itself. Major conservation concerns identified for Lake Ohrid are: (1) watershed impacts, (2) agriculture and forestry, (3) tourism and population growth, (4) non-indigenous species, (5) habitat alteration or loss, (6) unsustainable exploitation of fisheries, and (7) global climate change.Among the major (well-known) threats with high impact are nutrient input (particularly of phosphorus), habitat conversion and silt load. Other threats are potentially of high impact but less well known. Such threats include pollution with hazardous substances (from sources such as mines, former

show abstract

Spatial variability of recent sedimentation in Lake Ohrid (Albania/Macedonia)

Cited by 73 publications

References 32 publications

Spatial patterns of diatom diversity and community structure in ancient Lake Ohrid

Spatial patterns of diatom diversity and community structure in ancient Lake Ohrid

The spatial distribution and sedimentary processes of organic matter in surface sediments of Nam Co, Central Tibetan Plateau

A freshwater biodiversity hotspot under pressure – assessing threats and identifying conservation needs for ancient Lake Ohrid

Contact Info

Product

Resources

About