scholarly journals Are there Invasive Planktonic Microbes?

2019 ◽  
Vol 2 (2) ◽  
Keyword(s):  
Natural Population ◽  
Human Activities ◽  
Environmental Changes ◽  
Common Species ◽  
Species Level ◽  
Indigenous Species ◽  
Introduced Populations ◽  
Interannual Fluctuations ◽  
Non Indigenous Species ◽  
Gymnodinium Catenatum

The translocation of species by human activities is a problem that increases with the globalization. However, the examples of non-indigenous or exotic planktonic microbes can be questioned as they predominantly have cosmopolitan distributions and natural mechanisms for wide dispersion. In reality, the categorization of any species as non-indigenous requires solving two difficult issues: knowledge of where the ‘natural’ population is, and demonstration of a substantial geographic discontinuity between the supposed source and the introduced populations. With regard to planktonic microorganisms, a non-indigenous taxon could have been previously unnoticed during routine microscopical analyses due to: A) difficult identification at the species level in routine observations such as for the diatoms (Pseudo-nitzschia, Skeletonema, Thalassiosira, Pleurosigma), unarmoured dinoflagellates (Karenia, Karlodinium) and Raphidophytes, and B) species with strong interannual fluctuations of abundance, only detected during bloom periods when they are misinterpreted as newcomers (i.e., Coscinodiscus wailesii or Trieres chinensis, junior synonyms of C. cylindricus and T. regia, respectively, or Gymnodinium catenatum). Rather than attempting to add to the lists of non-indigenous species with planktonic microbes, the monitoring surveys should also pay attention in the less common species with important fluctuations of abundance, independent of tentative labels as exotic or indigenous, because they are potentially useful as bio-indicators of environmental changes.

scholarly journals Terrestrial ecosystems of the Antarctic Peninsula and their responses to climate change and anthropogenic impacts

2020 ◽  
pp. 84-97
Author(s):  
R. Bargagli ◽  
Keyword(s):  
Antarctic Peninsula ◽  
Native Species ◽  
Environmental Changes ◽  
Anthropogenic Impacts ◽  
Extreme Temperature ◽  
Terrestrial Ecosystems ◽  
Indigenous Species ◽  
Non Indigenous Species ◽  
Food Web Complexity ◽  
The Antarctic

Antarctica and the Southern Ocean are unique natural laboratories where organisms adapted to extreme environmental conditions have evolved in isolation for millions of years. These unique biotic communities on Earth are facing complex climatic and environmental changes. Terrestrial ecosystems in the Antarctic Peninsula Region (APR) have experienced the highest rate of climate warming and, being the most impacted by human activities, are facing the greatest risk of detrimental changes. This review provides an overview of the most recent findings on how biotic communities in terrestrial ecosystems of the Antarctic Peninsula Region (APR) are responding and will likely respond to further environmental changes and direct anthropogenic impacts. Knowledge gained from studies on relatively simple terrestrial ecosystems could be very useful in predicting what may happen in much more complex ecosystems in regions with less extreme temperature changes. The rapid warming of the APR has led to the retreat of glaciers, the loss of snow and permafrost and the increase of ice-free areas, with a consequent enhancement of soil-forming processes, biotic communities, and food web complexity. However, most human activity is concentrated in APR coastal ice-free areas and poses many threats to terrestrial ecosystems such as environmental pollution or disturbances to soilcommunities and wildlife. People who work or visit APR may inadvertently introduce alien organisms and/or spread native species to spatially isolated ice-free areas. The number of introduced non-indigenous species and xenobiotic compounds in the APR is likely to be greater than currently documented, and several biosecurity and monitoring activities are therefore suggested to Antarctic national scientific programs and tourism operators to minimize the risk of irreversible loss of integrity by the unique terrestrial ecosystems of APR.

A primer to metabarcoding surveys of Antarctic terrestrial biodiversity

2016 ◽  
Vol 29 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Paul Czechowski ◽  
Laurence J. Clarke ◽  
Alan Cooper ◽  
Mark I. Stevens
Keyword(s):  
High Throughput Sequencing ◽  
Environmental Changes ◽  
Indigenous Species ◽  
Terrestrial Habitats ◽  
Cryptic Taxa ◽  
Terrestrial Biodiversity ◽  
Non Indigenous Species ◽  
Changes Over Time ◽  
Continental Interior ◽  
Highly Uniform

AbstractIce-free regions of Antarctica are concentrated along the coastal margins but are scarce throughout the continental interior. Environmental changes, including the introduction of non-indigenous species, increasingly threaten these unique habitats. At the same time, the unique biotic communities subsisting in isolation across the continent are difficult to survey due to logistical constraints, sampling challenges and problems related to the identification of small and cryptic taxa. Baseline biodiversity data from remote Antarctic habitats are still missing for many parts of the continent but are critical to the detection of community changes over time, including newly introduced species. Here we review the potential of standardized (non-specialist) sampling in the field (e.g. from soil, vegetation or water) combined with high-throughput sequencing (HTS) of bulk DNA as a possible solution to overcome some of these problems. In particular, HTS metabarcoding approaches benefit from being able to process many samples in parallel, while workflow and data structure can stay highly uniform. Such approaches have quickly gained recognition and we show that HTS metabarcoding surveys are likely to play an important role in continent-wide biomonitoring of all Antarctic terrestrial habitats.

scholarly journals Juvenile pelagic fish assemblages in the coastal waters of Lebanon: Diversity, biological characteristics & landings

2019 ◽  
Author(s):  
Garabet Kazanjian
Keyword(s):  
Species Richness ◽  
Fish Assemblages ◽  
Niche Partitioning ◽  
Common Species ◽  
Indigenous Species ◽  
Northern Coast ◽  
First Maturity ◽  
Non Indigenous Species ◽  
New Recruits ◽  
Boops Boops

Small pelagic fishes constituted half of the Mediterranean landings and a considerable portion of the Lebanese catches. In this study, the purse seine fishery was analyzed between 2006 and 2007 in two sites along the northern coast of Lebanon.Thirty-six different fish species were collected, out of which seven constituted morethan 97% of the landings. Engraulis encrasicolus, Sardinella aurita and Sardinapilchardus composed 57.7%, 20.9% and 5.6% of the abundance of catches respectively and 31.3%, 19.2%, 9.2% of its biomass. Non-indigenous species comprised 7.2% of the total abundance and 18.7 % of the landing biomass. The fishery targeted mainly the new recruits (0+), and the vast majority of the catches were fishes below their size at first maturity. Diversity and species richness were high in the warmer in the months and low in the colder ones. Temperature and salinity were positively correlated with species richness, while the chlorophyll content of seawater was positively associated with diversity. Clear temporal patterns with distinct shifts of dominance within the landings were detected throughout the year for the most common species. Engraulids dominated catches from October to March, while the rest of the year was characterized by clupeids, Boops boops, and Scomber colias. A temporal niche partitioning seems to exist in the easternmost Mediterranean pelagic waters, possibly to minimize competition.

scholarly journals STUDY OF ECOSYSTEM OF THE SUKHUM BAY WITH EMPHASIS ANTHROPOGENIC IMPACT, ABKHAZIAN BLACK SEA COAST

2019 ◽  
Vol 22 ◽  
pp. 108-116
Author(s):  
Zhanna P. Selifonova ◽  
Pavel R. Makarevich ◽  
Ernest Z. Samyshev ◽  
Levard M. Bartsits
Keyword(s):  
Alien Species ◽  
Black Sea ◽  
Benthic Communities ◽  
Nutrient Status ◽  
Common Species ◽  
Indigenous Species ◽  
Macrophyte Community ◽  
Non Indigenous Species ◽  
Sea Area ◽  
First Time

For the first time in thirty years, baseline comprehensive studies plankton and zoobenthos of the Sukhum Bay were conducted and an assessment of its current environmental status was given. The summer phytoplankton abundance of the port of Sukhum was represented mainly by coccolithophorids  Emiliania huxleyi and diatoms algae, among the latter, the common species in polluted or eutrophic brackish waters were recorded. The presence of euglenic algae and cyanobacteria indicates a higher nutrient status, pollution and desalination of the sea area. The alien species Peridinium quinquecorne Abé (Dinophyceae) was recorded in the Abkhazian coastal waters for the first time. Totally, 7 species of tintinnids  belonging to 3 genera Favella, Tintinnopsis, Eutintinnus were established from the Sukhum Bay. Among them, the non-indigenous species Eutintinnus  tubulosus and E. apertus were noticed. Tintinnid ciliates accounted for ca. 5% of total ciliates abundance. The values of the abundance of aloricated ciliates were comparable to the values obtained  from offshore of bays and ports of the northeastern Black Sea. As the pressure of predators is reduced the well-pronounced peaks of holo- and meroplankton biomass were recorded in the last summer – early autumn. A significant part of total holoplankton biomass – 66.5 % (up to 1.1 g/m3) was composed of cladocerans  Penilia avirostris. The  meroplankton was dominated by larvae of bivalve mollusks Mytilaster lineatus,  polychaetes Polydora cornuta and cirripede barnacle Amphibalanus improvisus. The number of meroplankton in the open Sukhum port was 10–15 times lower above than a level of values obtained for ports and bays of the northeastern Black Sea. Among ichthyoplankton, the dominant species were Mullus barbatus ponticus, Diplodus annularis, Trachurus mediterraneus, Engraulis encrasicholus and Sciena umbra. Mean abundance of ichthyoplankton in vertical catches was 5–10 times lower than in offshore of Anapa and Gelendzhik of the northeastern Black Sea. And the proportion of dead eggs was 2 – 3 times higher than areas of these resort cities. The composition of macrozoobenthos was drastically depleted and resembled that of the polluted port complexes of the northeastern Black Sea. Heteromastus association  dominated in mud bottom sediments. Among spionid polychaetes, the worst invaders Streblospio gynobranchiata and Polydora cornuta have been recorded in soft bottom communities. Depletion of benthic communities, loss from the structure of the trophic web of the macrophyte community and appearance of cyanobacteria and a new alien species in the planktonic and benthic communities leads inevitably to imbalance of the structure of the Sukhum port ecosystem.

scholarly journals Local Drivers of Change in Southern Ocean Ecosystems: Human Activities and Policy Implications

2021 ◽  
Vol 9 ◽  
Author(s):  
Susie M. Grant ◽  
Cath L. Waller ◽  
Simon A. Morley ◽  
David K. A. Barnes ◽  
Madeleine J. Brasier ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Human Activities ◽  
Marine Mammals ◽  
Regional Scale ◽  
Policy Implications ◽  
Ecological Change ◽  
Indigenous Species ◽  
Ocean Ecosystems ◽  
Projected Changes ◽  
Non Indigenous Species

Local drivers are human activities or processes that occur in specific locations, and cause physical or ecological change at the local or regional scale. Here, we consider marine and land-derived pollution, non-indigenous species, tourism and other human visits, exploitation of marine resources, recovery of marine mammals, and coastal change as a result of ice loss, in terms of their historic and current extent, and their interactions with the Southern Ocean environment. We summarise projected increases or decreases in the influence of local drivers, and projected changes to their geographic range, concluding that the influence of non-indigenous species, fishing, and the recovery of marine mammals are predicted to increase in the future across the Southern Ocean. Local drivers can be managed regionally, and we identify existing governance frameworks as part of the Antarctic Treaty System and other instruments which may be employed to mitigate or limit their impacts on Southern Ocean ecosystems.

Meta-analysis on the ecological impacts of widely spread non-indigenous species in the Baltic Sea

2021 ◽  
pp. 147375
Author(s):  
Henn Ojaveer ◽  
Jonne Kotta ◽  
Okko Outinen ◽  
Heli Einberg ◽  
Anastasija Zaiko ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Meta Analysis ◽  
Ecological Impacts ◽  
Indigenous Species ◽  
The Baltic Sea ◽  
The Baltic ◽  
Non Indigenous Species

scholarly journals First Record of the Alien Species Procambarus virginalis Lyko, 2017 in Fresh Waters of Sardinia and Insight into Its Genetic Variability

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 606
Author(s):  
Daria Sanna ◽  
Ilenia Azzena ◽  
Fabio Scarpa ◽  
Piero Cossu ◽  
Angela Pira ◽  
...  
Keyword(s):  
Genetic Variability ◽  
Alien Species ◽  
Procambarus Clarkii ◽  
Mitochondrial Gene ◽  
First Record ◽  
Indigenous Species ◽  
Fresh Waters ◽  
Mediterranean Island ◽  
Marbled Crayfish ◽  
Non Indigenous Species

In the fresh waters of Sardinia (Italy), the non-indigenous crayfish species Procambarus clarkii has been reported from 2005, but, starting from 2019, there have been several reports of a new non-indigenous crayfish in southern and central areas of this Mediterranean island, and its morphology suggests that this species may be the marbled crayfish Procambarus virginalis. Forty-seven individuals of this putative species were analyzed, using the mitochondrial gene Cytochrome c Oxidase subunit I as molecular marker to identify this crayfish and investigate the level of genetic variability within the recently established population. Phylogenetic and phylogeographic analyses were carried out on a dataset including sequences from the Sardinian individuals and from all congenerics available in GenBank. Results showed that the new Sardinian crayfish belong to the species P. virginalis. All the sequences belonging to P. virginalis from European countries are identical, with only few exceptions found among Sardinian individuals. In conclusion, this paper highlights the occurrence of a new further alien species in the Sardinian fresh waters, which are already characterized by the high presence of non-indigenous species.

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