The generation of reliable and comparable time series data is an important aspect of environmental monitoring and is carried out with a variety of methodologies. In Marine Biology/Oceanography there has been an increasing degree of automation of data generation. Instead of individual measurement intervals of days, weeks or months, modern sensors can generate data oceanographic data at frequencies of minutes or even seconds and at remote locations such as the open ocean and the deep sea. While these sensors were originally designed to measure physical parameters such as temperature, salinity and pH. they are increasingly being developed for the assessment of biological diversity in the water column and marine sediments. Novel technologies include automated sample collection, genetic sequencing and other molecular assays, as well as methods that combine flow cytometry with imaging techniques and automated species identification algorithms applied to digital images.
The different types of sensors used for biodiversity assessments are often at an early stage of development and lack technical and analytical standardization. Consequently, the comparability of data sets generated by different sensors is limited. The extent to which these numerous and diverse datasets can be integrated into existing time series sites has not yet been evaluated.
In the proposed symposium we will therefore invite key developers of these new techniques, biodiversity experts and taxonomists, as well as potential users and technical experts (for instance IT technicians) to discuss these novel technologies in marine biodiversity research and develop mechanisms for standardization and intercalibration. We will also identify possible projects that can be used to evaluate the applicability of sensors in a time series context specifically to investigate long-term changes in marine ecosystems
Marine biodiversity is of fundamental importance for human well-being because it is vital for the functioning of the earth biosphere through processes such as oxygen production, carbon fixation, and the transfer of energy and recycling of matter in marine food webs. Climate change (e.g., ocean warming, acidification, changes in hydrography, etc.) is expected to have severe impacts on marine biodiversity. Notably, changes in phytoplankton composition are expected to have consequences that ripple through entire food webs. Phytoplankton are photosynthetic microorganisms that account for roughly half of global net primary productivity (NPP), as well as significant CO2 drawdown from the atmosphere. As primary producers they are fundamental for marine ecosystem function and resulting ecosystem services. As a consequence, changes in phytoplankton community structure and biogeography (range shifts) as a response to climate change are currently topical issues in marine ecology. Elucidation and quantification of changes in marine plankton biodiversity require long-term observations to link biological effects to their underlying physical-chemical drivers. Despite this its great importance, the task of measuring changes in plankton diversity on a global scale is severely hampered by difficulties in maintaining regular observations of plankton on an adequate temporal and spatial scale, as well as with appropriate taxonomic resolution. As such, new automated high throughput approaches are needed to improve and facilitate long-term observations of marine plankton biodiversity.
Research processes in many fields of marine science are undergoing striking changes, becoming more and more automated and, as a consequence, facilitating much higher frequencies of observation. Two examples of emerging high throughput, and at least partly automated, technologies are (1) Flow cytometry techniques that are coupled with high frequency imaging and (2) High throughput (and other) molecular techniques.
While methodological and analytical advances in the field of imaging flow cytometry and molecular biology hold great promise for an urgently needed improvement in the understanding of marine biodiversity, the challenges are equally great in terms of computational, data storage and archival needs, as well as new approaches needed for data analysis and visualisation. Many different molecular analysis approaches and protocols, as well as optical observation systems are being developed in unconnected research projects (Figure 1). This provides the additional challenge that different data standards, storage technologies, databases and analysis pipelines will ultimately limit the comparability of data sets from these systems and also limit the usability of the individual data sets for large scale ecological analyses. As a consequence, the integration of these new approaches into long-term investigations is very challenging. Nevertheless, many of the new techniques being developed are destined to eventually be used for long-term observations, while an additional danger is that they are introduced into existing observation programmes without enough focus on the comparability of data from different measuring devices, consequently threatening the internal consistency of a given time series (in addition to limiting the comparability between time series).
The above problems are not new, but have been encountered for time series with conventional manual sampling. In some cases, it has taken several decades to overcome issues regarding the inter-calibration and standardization in the face of shifting methods. With the emerging high throughput techniques for biodiversity assessments, we have an opportunity to avoid similar problems.
It is important to emphasize that although these two methodological approaches have distinct differences there is considerable added value in addressing them together. First, the two methodologies are often used for the same time series/ observatories. Second, they provide highly complementary information. Imaging, for instance, is more rapid and can also be used to annotate sequence information, while sequencing can provide a level of taxonomic and evolutionary detail that in many cases cannot be discerned from images alone. It is therefore timely to network respective communities with the goal of harmonizing approaches and protocols as much as possible, and evaluating the synergistic potential of the two methodologies to refine and facilitate long term observation of marine plankton biodiversity.
Aims of this Symposium
There are five major aims of this symposium that, taken together, will represent a large step forward for research related to exploring and understanding global change consequences for marine plankton biodiversity (see also Figure 2):
I. Assess and discuss advantages and pitfalls of the methodologies
II. Develop a strategy for protocol standardization for the observation of marine plankton biodiversity via imaging flow cytometry and molecular methods.
III. Improve communication between scientists working with the two methodologies
IV. Identify and discuss potential synergistic effects of an application and combination of imaging flow cytometry and molecular methods in ongoing marine long term plankton observation programs.
V. Develop a roadmap to promote the integration and better exploitation of these new methodologies in marine plankton observation programs.