Table 2 Top-50 most voted questions in our survey (in bold in the main text when mentioned)

1

2257

V

How does meiofaunal biodiversity contribute to ecosystem function, integrity, and sustainability in the context of anthropogenic activities and global change?

2

2210

V

Is meiofauna taxonomical and functional diversity important in assessing anthropogenic impacts and global change on ecosystems?

3

2209

V

Are meiofauna good indicators of ecosystem quality status and functioning or do they need support from additional sources of evidence?

4

2193

VIII

How can we promote the interest for meiofauna amongst students and young researchers thereby ensuring the future of the field?

5

2189

V

Can meiofauna be used to understand better how pollution impacts ecosystems as a whole?

6

2187

V

How do meiofauna contribute to ecosystem resilience, particularly after a disturbance?

7

2177

V

What are the most damaging impacts for meiofauna (for example extraction of resources, modification of habitat, creation of man-made structures, pollution, warming, ocean acidification, deoxygenation, etc.)?

8

2162

II

Can sampling protocols be standardised to gather comparable distribution and ecological data worldwide?

9

2160

VII

How and how much do meiofauna influence nutrient cycling in different ecosystems?

10

2157

V

What are the main effects on meiofauna caused by anthropogenic pollution?

11

2154

V

Are meiofaunal organisms a good tool in evaluating the success of habitat restoration projects in different ecosystems, for example, by assessing ecosystem function and health?

12

2151

I

How can we efficiently and reliably estimate and measure meiofaunal species diversity?

13

2148

II

What are the main knowledge gaps in meiofaunal diversity?

14

2131

V

What are the roles of meiofauna in the natural restoration process that follow anthropogenic impacts?

15

2130

V

Are meiofaunal species effective indicators for conventional pollutants and emerging contaminants (pharmaceuticals, pesticides, personal care products)?

16

2126

II

Which are the main barriers for meiofaunal species dispersal/colonisation?

17

2124

V

Are meiofauna more or less resilient compared to other benthic components in an ecosystem when under pressure of anthropogenic impacts and global change?

18

2120

V

What are the main effects on meiofauna caused by climate change?

19

2119

VIII

How can we further promote and/or sustain the use of meiofauna as a tool or requirement in standard protocols for assessing and monitoring the quality status of ecosystems?

20

2110

VI

How does connectivity among different habitats affect meiofaunal diversity patterns across different spatial scales?

21

2108

I

How species-rich are meiofauna on a regional and global scale?

22

2106

VIII

How can we strengthen collaboration to speed up the production of a joined global inventory of meiofaunal species in times of biodiversity crisis and global change?

23

2098

V

Do meiofauna in different habitats respond differently to similar anthropogenic impacts or global change?

24

2093

II

What drives patterns of meiofaunal diversity over large-scale gradients?

25

2092

V

Are there suitable early warning meiofaunal organisms, i.e. organisms useful to detect early stages of anthropogenic activities and global change?

26

2090

V

What functional traits or adaptations make meiofauna resistant against the impacts of anthropogenic activities and global change?

27

2086

VII

What do we know about the contribution of meiofauna to global carbon cycling and sequestration?

28

2084

VII

What are the most critical roles of meiofauna in biogeochemical cycling and how do they differ between different ecosystems?

29

2083

V

How will global change affect meiofauna distribution ranges and biogeography; for example, through contraction, expansion or shifts?

30

2080

VI

Are the ecological paradigms that we have developed for macroscopic organisms (for example, vertebrates, plants) transferable to a microscopic context, or do we need new theories and approaches to understand the population and community ecology of meiofauna?

31

2077

I

Do cosmopolitan meiofaunal species exist, do they represent complexes of cryptic species with narrower distributions, or are they just an artefact of poor taxonomy?

32

2072

VI

How do meiofaunal animals sense and react to their environment?

33

2071

V

Which are the most accurate monitoring protocols and tools, including meiofauna-based metrics and indices, to quantify meiofaunal changes in response to anthropogenic impacts and global change?

34

2069

V

How do anthropogenic activities and global change affect the different levels of biological organisation (for example genes, proteins and other compounds, cells, organs, organisms, life stages, populations, communities) in meiofaunal communities, and how could they be used as indicators?

35

2064

VII

What is the relative importance of ecological interactions between meiofauna and prokaryotes, such as facilitation and predation, in ecosystem processes?

36

2063

V

What is the best way to measure meiofauna diversity when assessing impacts from anthropogenic activities and global change?

37

2063

I

What patterns of diversity exist and how do they vary among different groups of meiofauna?

38

2063

II

What drives patterns of meiofaunal phylogenetic and functional diversity up to global scales?

39

2060

VII

Do meiofauna drive organic contaminant biodegradation and heavy metal distribution in different ecosystems?

40

2057

VI

What is the relative contribution of abiotic features versus biotic interactions in determining community assembly in meiofauna?

41

2048

VII

How and how much do meiofauna bioturbation affect transport, transformation, and burial of marine litter and microplastics?

42

2036

II

What are the environmental and biological mechanisms that drive dispersal distance in meiofaunal species?

43

2033

II

What is the relative contribution of local versus regional ecological factors on the distribution of meiofaunal organisms?

44

2030

VIII

Which community efforts are needed to dispel the taxonomic impediment and train new generations of meiobenthologists?

45

2030

VII

How would aquatic ecosystems function without meiofauna and to what extent can meiofauna sustain rates of key biogeochemical processes alone?

46

2023

VII

How and how much do meiofauna living in anoxic and sulfidic sediment layers influence ecosystem functions?

47

2018

V

Do permanent and temporary meiofauna respond differently to anthropogenic impacts and global change and what are the implications of these differences in impact assessments and monitoring?

48

2017

V

What are the main effects on meiofauna caused by microplastics?

49

2017

VII

Are the meiofauna a quantitatively important food source for fish and other vertebrates?

50

2013

V

What are the main effects on meiofauna caused by physical disturbance?