Confocal laser scanning microscopy: using cuticular autofluorescence for high resolution morphological imaging in small crustaceans

The utility of cuticular autofluorescence for the visualization of copepod morphology by means of confocal laser scanning microscopy (CLSM) was examined. Resulting maximum intensity projections give very accurate information on morphology and show even diminutive structures such as small setae in detail. Furthermore, CLSM enables recognition of internal structures and differences in material composition. Optical sections in all layers and along all axes of the specimens can be obtained by CLSM. The facile and rapid preparation method bears no risk of artefacts or damage occurring to the preparations and the visualized specimens can be used for later analyses allowing for the investigation of irreplaceable type specimens or parts of them. These features make CLSM a very effective tool for both taxonomical and ecological studies in small crustaceans; however, the maximum thickness of the specimens is limited to a few hundred micrometers. Three-dimensional models based on CLSM image stacks allow observation of the preparations from all angles and can permit, improve and speed up studies on functional morphology. The visualization method described has a strong potential to become a future standard technique in aquatic biology due to its advantages over conventional light microscopy and scanning electron microscopy

Dissecting copepod diversity at different spatial scales in southern European groundwater

Galassi, Diana M.P., Stoch, Fabio, Brancelj, Anton (2013): Dissecting copepod diversity at different spatial scales in southern European groundwater. Journal of Natural History 47 (5-12): 821-840, DOI: 10.1080/00222933.2012.738834, URL: http://dx.doi.org/10.1080/00222933.2012.73883

Towards an optimal sampling strategy to assess groundwater biodiversity: comparison across six European regions

1. Reliable assessments of groundwater biodiversity are urgently needed to resolve current issues relating to the protection of aquifers. The assessment of groundwater biodiversity is hampered by the physical complexity and difficult access to the subterranean environment, which is related to the vastness, high degree of fragmentation and environmental heterogeneity of groundwater systems. Knowledge on groundwater biodiversity is also biased towards penetrable karstic habitats (caves), whereas other common habitats such as those found in porous aquifers have been neglected. This situation calls for a standardised and comprehensive strategy to sample an exhaustive and balanced set of groundwater habitats. 2. A standardised sampling protocol aimed at capturing the main sources of environmental heterogeneity within regions was applied in six regions across Europe. Four hierarchical levels were considered: (i) region (c. 400 km2); (ii) basin (c. 100 km2); (iii) aquifer type (karstic or porous) and (iv) habitat (hyporheic and phreatic zones for porous aquifers; saturated and unsaturated zones for karst aquifers). A total of 192 sampling sites equally distributed among habitats were sampled within each region. 3. Stygobiotic species richness significantly varied across regions, probably as a result of important difference in physical and biogeographical characteristics among the regions. Only one species (Graeteriella unisetigera) occurred in all six regions, underlining the narrow geographic range and high degree of endemism of stygobiotic fauna. The low frequency of occurrence of stygobionts also points to the importance of rarity in ground waters and its relevance for drawing up sampling designs. 4. Rarefaction curves were calculated to determine sampling efficiencies within each region. Despite the high sampling effort, the curves did not reach saturation, especially in the Cantabria, Lessinia and Krim regions, which had the greatest numbers of rare species. 5. Species accumulation curves were also calculated by c

Scientists\u27 Warning on the Conservation of Subterranean Ecosystems

In light of recent alarming trends in human population growth, climate change, and other environmental modifications, a “Warning to humanity” manifesto was published in BioScience in 2017. This call reiterated most of the ideas originally expressed by the Union of Concerned Scientists in 1992, including the fear that we are “pushing Earth\u27s ecosystems beyond their capacities to support the web of life.” As subterranean biologists, we take this opportunity to emphasize the global importance and the conservation challenges associated with subterranean ecosystems. They likely represent the most widespread nonmarine environments on Earth, but specialized subterranean organisms remain among the least documented and studied. Largely overlooked in conservation policies, subterranean habitats play a critical role in the function of the web of life and provide important ecosystem services. We highlight the main threats to subterranean ecosystems and propose a set of effective actions to protect this globally important natural heritage