A Trillion Species?

For many years one of the most famous questions in biodiversity science was "how many species live on earth". Five years ago researchers predicted ∼8.7 million (±1.3 million SE) eukaryotic species globally. Estimating the number of species on Earth has always been a difficult business and some extrapolations are educated guesses. That might explain why estimates of the total number of species vary between 10  and 100 million but 250 years of taxonomic study has formally described just about 1.8 million of them.

The big unknown is microbial (prokaryotic) life. With the advent of high-throughput sequencing numbers and estimates for microbial taxa skyrocketed by orders of magnitude and researchers are starting to think really really big:

...this period of discovery has uncovered few, if any, general rules for predicting microbial biodiversity at scales of abundance that characterize, for example, the ∼10¹⁴ cells of bacteria that inhabit a single human or the ∼10³⁰ cells of bacteria and archaea estimated to inhabit Earth. Such findings would aid the estimation of global species richness and reveal whether theories of biodiversity hold across all scales of abundance and whether so-called law-like patterns of biodiversity span the tree of life.

The realization that microorganisms were significantly under-sampled caused an explosion in new microbial sampling efforts over the past several years, including the collection of human-related microorganisms by the National Institutes of Health's Human Microbiome Project; marine microorganisms by the Tara Oceans Expedition; and aquatic, terrestrial and host-related microorganisms by the Earth Microbiome Project. 

Two US scientists now combined microbial, plant and animal community datasets from government, academic and citizen science sources, resulting in the largest compilation of its kind. Altogether, these data represent over 5.6 million microscopic and non-microscopic species from 35,000 locations across all the world's oceans and continents, except Antarctica.

We suspected that aspects of biodiversity, like the number of species on Earth, would scale with the abundance of individual organisms. After analyzing a massive amount of data, we observed simple but powerful trends in how biodiversity changes across scales of abundance. One of these trends is among the most expansive patterns in biology, holding across all magnitudes of abundance in nature.

Scaling laws, like those discovered by the colleagues, have been used to accurately predict species numbers for plant and animal communities on smaller scales, e.g. the number of species scales with the area of a landscape. The researchers focused on the question if aspects of biodiversity scale with something as simple as the abundance of organisms. Their message is that the relationships are not only simple but powerful, resulting in the estimate of upwards of 1 trillion species.

These results suggest that identifying every microbial species on Earth is an almost unimaginably huge challenge. To put the task in perspective, the Earth Microbiome Project has so far cataloged about 6 million bacterial taxonomic units (genus or species level taxa). 

Of those cataloged species, only about 10,000 have ever been grown in a lab, and fewer than 100,000 have classified sequences. Our results show that this leaves 100,000 times more microorganisms awaiting discovery - and 100 million to be fully explored. Microbial biodiversity, it appears, is greater than ever imagined.

Pogosta Disease, Karelian fever or Ockelbo disease

BIO Photography Group, Biodiversity Institute of Ontario

Have you ever heard of  Pogosta Disease, Karelian fever or Ockelbo disease? To me these were new but apparently they are all the same viral infection named after the different northern European regions it occurs (Finland, Russia, Sweden). In the 1980s it was shown to be associated with a strain of SINV isolated from mosquitoes. SINV is a mosquito-borne RNA virus, currently divided into five genotypes. One of those comprises of strains from northern Europe and South Africa and is called the African–European genotype. 

The symptoms of the disease usually include a rash, as well as mild fever and other flu-like symptoms. Normally the symptoms cease after about 5 days. However, in some cases, patients develop a painful arthritis in the joints that may persist for months or even years. A typical patient is a middle-aged person who has been infected through a mosquito bite while picking berries in the autumn.

In August and September of 2013, an outbreak of Ockelbo disease occurred in northern Sweden, along the coastline of the Gulf of Bothnia, north of the endemic region where SINV is usually found. A group of Swedish researchers investigated the causative agent of this unexpected outbreak by using novel techniques (e.g. DNA barcoding) for vector identification and a high-throughput screening assay for virus detection.

The mosquitoes were initially screened as large pools by SINV-specific quantitative RT-PCR, and the SINV-positive mosquitoes were species determined by single-nucleotide polymorphism (SNP) analysis, followed by sequencing the barcoding region of the cytochrome oxidase I gene. The proportion of the collected mosquitoes was determined by a metabarcoding strategy.

The colleagues were able to isolate a new SINV strain (Lövånger) linked to strains from Ilomantsi, Finland, and Tärnsjö, Sweden. A pool of 1600 mosquitoes composed members of different genera (Culex, Culiseta, Aedes) was identified by metabarcoding. The only SINV-positive species was Culiseta morsitans which is also known to be a vector for Eastern equine encephalitis in North America.

Genetic diversity of coral reefs

Coral reefs are widely known for their stunning array of color, shape and forms of life, making them a model for extreme biodiversity. Hidden within the multitude of reef inhabitants, but no less important, is their genetic diversity which is linked to adaptive capacity, extinction risk of species, and the overall functioning of ecosystems, so conservation strategies often call for preserving areas of high genetic diversity.

However, there is little direct data to guide debates such as whether many small versus one large reserve would be better to protect genetic resources. Researchers from the University of Hawai'i at Mānoa (UHM) School of Ocean and Earth Science and Technology, the University of California, Santa Barbara (UCSB), University of St. Andrews, and University of Melbourne discovered that large areas of intact coral reef with extensive live coral cover, not disturbed by humans or climate change, harbor the greatest amount of genetic diversity.

The colleagues assessed genetic diversity from over 17,000 samples taken from 47 common reef-associated species across the Hawaiian Archipelago and found that genetic diversity varies across the inhabited Main Hawaiian Islands, extending the argument for targeted protection of reefs throughout the Main Hawaiian Islands. Notably, Hawai'i Island has the greatest amount of coral reef area, harbors the greatest proportion of genetic diversity, and serves a unique, and particularly influential role due to its large size at the margin of the chain. Nihoa and Ni'ihau, which sit at the transition between Papahānaumokuākea Marine National Monument and the Main Hawaiian Islands, also stand out and warrant future research and protection due to intriguing combinations of high genetic divergence and unusual fish composition.

Genetic diversity is widely accepted as critical for adaptation to a changing climate. Although coral bleaching in Hawaii has been relatively rare over the past few decades by comparison to many other places in the Pacific, this stressor still exerts a large impact on the reef communities studied. Research shows that areas which experienced the most frequent coral bleaching conditions also showed depressed levels of genetic diversity, not just for corals but for the entire community of fishes and other invertebrates associated with those habitats.

This negative impact of thermal stress on genetic diversity suggests that climate change will compromise the adaptive capacity and genetic integrity of not just corals but the entire coral reef community.

Identifying features of the landscape that are associated with biodiversity hotspots is one of the key strategies for conservation. The researchers involved in the study plan to follow up on evidence in their dataset that the same large-scale ecological rules that predict species diversity also predict genetic diversity. If that is true it would allow rapid assessment of species diversity using DNA analysis and thereby new metrics of resilience and adaptive capacity.

It is all about the building materials

Leafcutting bees like to make their nests in cavities or in soft rotting wood provided through hollow plant stems or decaying logs. Once a suitable spot has been found, they will build cells using pieces of leaf as lining, by overlapping segments of leaf to make a cylindrical cavity that looks a little like a cigar. Each cell is sealed up with a little segment of leaf. The bees cut leaves from various trees, shrubs, and wildflowers. In parts of Europe, some species line their egg cells with petals instead of leaves. 

The availability of suitable nesting material may limit the geographical ranges and abundances of particular leafcutter bee species. The problem is that their preferences have rarely investigated. For good reasons as the identification of preferred plant species via morphological characters of the leaf fragments is very challenging and direct observation of bees cutting leaves is more than tedious.

Reason enough for a Canadian researcher to barcode the leaf fragments used for cell construction by three different species of the genus Megachile. Two of those species were introduced (Megachile rotundata and Megachile  centuncularis), the third was a native species (Megachile pugnata).  

Interestingly, there was considerable overlap between the preferred species for both introduced bees while the native species showed the least diverse suite of plant species it uses. In addition, the study shows that antimicrobial properties were present in all but six plants collected; all these were exotic plants and none were collected by the native bee, M. pugnata. 

Citizen scientists key to future ecology field research?

Today, research universities scrutinize prospective environmental science faculty candidates, weighing in particular their potential to produce impactful publications and secure large external grants. When can any of us recall a job posting for an academic, tenure-track faculty position that mentioned a transdisciplinary background in natural history as a selection criterion? That omission may exclude those self-identified naturalists and in doing so may be affecting our field in ways we have yet to fully understand. If natural history has lost relevance and has been relegated to the dusty shelves of museums and the weekend pursuits of amateur enthusiasts, then this academic hiring trajectory is justified. However, if it is relevant and arguably constitutes the building blocks for fostering the development of the next Robert MacArthur, E. O. Wilson, or Ruth Patrick, then we should reconsider the path we are on.

A new survey of early-career scientists and environmental-science professionals found that only 11 percent felt their academic training alone provided the needed exposure to natural history, which can be defined as the observation of organisms in their natural environment. The survey coincides with a shift in ecology away from teaching and research rooted in natural history and toward modeling, laboratory and theoretical research, which tend to attract more grant funding and publications in higher-impact academic journals. This shift is occurring despite the cross-disciplinary connections natural history research creates among species, habitats and ecosystems.

For the survey project, researchers questioned 185 professionals, assessing the attitudes and perceptions related to natural history by early-career scientists and environmental-science professionals across 31 universities in California.

Among the findings:

• Of the scientists surveyed, 93 percent agreed that natural history is relevant to science.
• About 70 percent believed it is essential to conduct field-based research.
• Only 54 percent felt inadequately trained to teach a natural-history course.
• More than 80 percent said they would benefit from additional training in natural history.
• Nearly 82 percent of respondents indicated that writing grants, research reports and manuscripts for publication was a daily to monthly component of their job.
• Just more than half indicated that conducting field research was a regular aspect of their employment.
• Only 24 percent had been given the opportunity to participate in a citizen science-type field campaign, which is defined as the collection and analysis of data relating to the natural world by members of the general public, typically in collaboration with professional scientists.

Building on previous experience with citizen science research, the researchers argue that citizen science may be the key to keeping natural history relevant in the 21st century and keeping pace with the direction of modern ecology.

Modern natural historians are in a unique position to act as a bridge between science and nonscientists and should capitalize on the inclusion of the public in ways that will empower them to make societal changes to combat looming environmental and conservation issues.

Biodiversity threat data gaps

Reducing rates of biodiversity loss and achieving environmental goals requires understanding what is threatening biodiversity, where risks occur, how fast threats are changing in type and intensity, and what are the most appropriate actions to avert them. A UN report proposed specific policy recommendations for mobilizing the “big data” revolution for sustainable development and environmental protection. The combination of crowd-sourced data, large-scale ground-based monitoring schemes, and satellite earth-observation missions is seemingly capable of unprecedented insight into global threats to biodiversity and how human interventions are altering those threats.

But, do we have the reliable and accessible data we need to understand the threats to biodiversity, where they occur and how quickly change is happening? It seems not. A new study shows those data are largely missing. We are lacking key information on important threats to biodiversity such as invasive species, logging, bush meat harvesting, and illegal wildlife trade. 

Over the past two years a consortium of 18 organizations compiled available global data on biodiversity threats. They reviewed 290 data sets ranging from remote sensing via satellites to citizen-science initiatives and marked them on five attributes required for conservation assessments. Datasets should be freely available, up to date, repeated, at appropriate spatial resolution, and validated for accuracy. 

Only 5% of the datasets satisfied all attributes. In some cases, the data needed for effective conservation policy already exists but are not accessible due to associated costs, commercial considerations or intellectual property arrangements. What's needed in such cases are agreements between conservation organizations and private companies, such as the one between IHS Energy and UNEP-WCMC that allow non-commercial use. The authors of the study consider governments as another  valuable future source of information. Some recent Open Government Initiatives e.g. in the UK and US have made more than 200,000 datasets freely available, including several that are relevant to environmental conservation. This should be adopted in other nations as well.

The colleagues also stress that filling these data gaps need not start from scratch. Several existing datasets, such as those dealing with invasive species on islands around the world, can be scaled up if appropriately resourced.

We were surprised that so few datasets met all of the five attributes we believe are required for 'gold standard' of data. We live in the age of Big Data, but are effectively flying blind when it comes to understanding what is threatening biodiversity around the world.

DFO PostDoc Position

Developing metabarcoding tools for environmental DNA-based biomonitoring in aquatic ecosystems

Fisheries and Oceans Canada: Pacific Biological Station, Nanaimo, British Columbia

A post-doctoral fellow with an interest in applied ecological and evolutionary genomics and aquatic ecosystems is being sought to lead the development of metabarcoding-based biomonitoring approaches to meet federal regulatory needs.

Multiple projects are underway. The successful candidate will play a lead role in a multi-disciplinary project on validating the use of environmental DNA (eDNA)-based metabarcoding (targeting meoifauna) for benthic impact assessments of salmon farms in coastal British Columbia. Salmon aquaculture causes organic enrichment of surrounding sediments which affects biodiversity and biomass of benthic fauna concomitant with sediment chemical changes. Existing environmental impact assessments rely on manual morpho-taxonomy or abiotic proxies of organic loading with uncertain accuracy. The project aims to develop an efficient and reliable lower-cost alternative based on cataloging the diversity and abundance of benthic communities through metabarcoding of environmental DNA (eDNA).

The successful candidate will also play a key collaborative role within two other projects aimed at developing metabarcoding based eDNA biosurveillance of aquatic invasive species (AIS). Aquatic invasive species (AIS) pose a major threat to freshwater aquatic ecosystems and fisheries in BC; detecting new invasions early and accurately assessing existing AIS distributions are important to maximize the chance for effective management intervention.

The successful candidate will have a PhD in ecological and/or evolutionary genomics or another relevant area and will demonstrate well-developed bioinformatics and computational skills (including programming, e.g. Perl, R, Unix, Python) as applied to the analysis of next-generation sequencing data. Experience in the preparation of samples for NGS (Illumina) and knowledge of barcoding, metabarcoding, and/or environmental DNA sampling in aquatic systems would be an asset but not a requirement. Candidates should demonstrate a strong track record of publication and be willing to work as part of a collaborative team.

A 2 year Postdoctoral Fellowship position starting by January 2017 is available with stipend funding at NSERC Visiting Fellowship rates. Applications from international candidates will be accepted. For more information and to review eligibility criteria.

To be considered for this position, please send your CV and brief email text explaining your suitability to 

Cathryn Abbott, Ph.D.

Research Scientist, Pacific Biological Station