TRAIT-BASED APPROACHES TO OCEAN LIFE traitspace.com

Keynotes Brian Enquist Lionel Guidi Image: Erik Selander Alexandra Worden Neil Banas

CHICHELEY HALL, BUCKINGHAMSHIRE, UK 18th to 21st August, 2019 FOURTH WORKSHOP ON TRAIT-BASED APPROACHES TO OCEAN LIFE

Table of Contents Schedule ...... 2 Keynote Speakers ...... 5 Abstracts ...... 7

1 Schedule

Sunday 13:00-14:00 Lunch

18th August 14:00-14:10 Welcome & Introduction Session 1: Traits, environments, ecology and evolution 14:10-15:10 Keynote: Brian Enquist The past, present, and future of trait- based ecology: Toward a more predictive framework 15:10-15:30 Davi Castro Tavares Traits shared by marine megafauna and their relationships with ecosystem functions and services 15:30-15:50 Stephanie Dutkiewicz Biogeochemical and ecological redundancy in phytoplankton communities 15:50-16:10 Tea/Coffee 16:10-16:30 Stephanie Green A traits-based framework to account for the influence of predator-prey interactions on species distribution under global change 16:30-16:50 David Talmy Trade-offs modify ecosystem biomass structure along trophic gradients

16:50-17:10 Aleksandra Does initial diversity influence Lewandowska phytoplankton response to environmental change? 17:10-17:30 Elena Litchman Traits and immigration determine species abundance distributions in experimental phytoplankton communities 17:30-19:00 Ice-breaker

19:00-20:30 Dinner

21:30 Bus to CMDC

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Monday Session 2: Food-webs and Trophic Interactions 19th August 09:00-10:00 Keynote: Neil Banas Copepod life-history traits along Arctic Ocean transport corridors: Scaling up from the lab to a rapidly changing seascape 10:00-10:20 Christoph Plum Interactive effects of resource supply, phytoplankton composition and macrozooplankton grazing on phytoplankton stoichiometry along the West Antarctic Peninsula 10:20-10:40 Camila Serra-Pompei Emergent patterns in size-structured models of copepod communities

10:40-11:00 Tea/Coffee 11:00-11:20 Daniel van Denderen Vertical feeding strategies and pelagic-benthic energy flows determine fish food-web structure across marine ecosystems 11:20-11:40 Øyvind Fiksen Dying from the lesser of three evils - facilitation and non-consumptive effects emerge in a model with multiple predators 11:40-12:00 Andrew Pershing Changes in community properties under rapid warming

12:00-12:20 Mark Miller Stability and persistence of reef fish functional groups

12:20-12:30 Discussion Info about discussion sessions

12:30-13:30 Lunch

13:30-14:45 Discussion

14:45-15:00 Tea/Coffee

15:00-16:00 Discussion

16:00-17:00 Round table discussion 17:00-17:30 Plenary Discussion Summary of discussions by leads, and a general discussion 17:30-19:00 Poster Session 1

19:00-20:30 Dinner 21:30 Bus to CMDC

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Tuesday Session 3: Multifarious lifestyles of marine microbes

20th August 09:00-10:00 Keynote: Alex Worden

10:00-10:20 Christopher Follett Geometric Niche Partitioning of Nitrogen- Fixers in the Sea

10:20-10:40 Kasia Kenitz Environmental and ecological drivers of variability in chain-forming marine diatoms

10:40-11:00 Tea/Coffee 11:00-11:20 Suzana Gonçalves Leles Mixotrophy and the succession of plankton trophic strategies within ecosystem models

11:20-11:40 Holly Moeller Trait-based evolution of acquired phototrophs: New models for complex endosymbiosis 11:40-12:00 Ursula Gaedke The role of trade-offs and mutual trait adaptation across three trophic levels: Evidence from a natural plankton food web and simulation models 12:00-12:20 Joey Bernhardt The evolution of competitive ability in phytoplankton

12:20-12:30 Discussion

12:30-13:30 Lunch

13:30-17:30 Recreation

17:30-19-00 Poster Session 2

19:00-20:30 Dinner

21:30 Bus to CMDC

Wednesday Session 5: Traits, Networks and Ecosystem Function 21st August 09:00-10:00 Keynote: Lionel Guidi High-throughput sequencing and imaging: New avenues for trait based modeling?

10:00-10:20 Emile Faure From genes to functional traits in the global ocean: de novo plankton functional types from environmental metagenomics data 10:20-10:40 Anna Neuheimer Trait-based explanations of genetic connectivity patterns for zooplankton and fish. 10:40-11:00 Tea/Coffee 11:00-11:20 George Hagstrom Trait-Based Models of Phytoplankton Stoichiometry: Nutrient Uptake, Environmental Drivers, and Genomics. 11:20-11:40 Emily Zakem Incorporating metabolic diversity into trait- based modeling frameworks with metabolic functional types 11:40-12:30 Plenary Discussion 12.30-13:30 Lunch, Departure

4 Keynote Speakers

BRIAN ENQUIST UNIVERSITY OF ARIZONA

I’m a broadly trained plant biologist and ecologist. My collaborative lab group strives to develop a more integrative, quantitative, and predictive framework for biology, community ecology, and large-scale ecology. In particular, we aim to link biological measures across spatial and temporal scales in ecology and evolution. My research focuses on three core areas:

(1) Scaling and Functional Biology/Ecophysiology – highlighting and deducing how general scaling rules, climate, and physical constraints influence organismal form, function, and diversity;

(2) Macroecology – assessing the ecological, macro ecological, biogeographic and evolutionary ramifications of the above organismal rules/constraints;

(3) Novel approaches – utilizing novel computation, big data, statistical, and visualisation tools to assess how differing climate change scenarios will influence the distribution of diversity and functioning of forests and ecosystems. Our research involves focus on field work, big datasets, scaling, developing theory and informatics infrastructure, empirically measuring numerous attributes of organismal form and function, utilizing physiological and trait-based techniques, and assessing macroecological and large-scale patterns. To address these questions my lab group often work in contrasting environments including tropical forests, on elevation gradients, and in high alpine ecosystems. Dr. Enquist is a Professor of Biology at the University of Arizona. He is also external professor at the Santa Fe Institute. He is a broadly trained biologist, plant biologist and an ecologist. He is a Fulbright Fellow, has been listed in Popular Science Magazine as one of their "Brilliant 10", and was elected as a Fellow of the American Association for the Advancement of Science (AAAS) in 2012 and the Ecological Society of America (ESA) in 2018.

ALEXANDRA WORDEN MONTEREY BAY AQUARIUM RESEARCH INSTITUTE

Alexandra Worden earned a B.A. in History from Wellesley College, with a concentration in Earth, Atmospheric and Planetary Sciences at M.I.T. She remained at M.I.T. for two years after graduating as a research technician. She then moved to the University of Georgia, where she received a NASA Earth Systems Science Fellowship (1996- 1999) and completed her Ph.D. in Ecology in 2000.

Dr. Worden then went on to conduct research on microbial interactions at Scripps Institution of Oceanography as an NSF Microbial Biology Postdoctoral Fellow, before accepting an Assistant Professorship at the Rosenstiel School of Marine and Atmospheric Science, University of Miami. In 2007 she joined the Monterey Bay Aquarium Research Institute (MBARI), where she leads a microbial ecology research and technology development group. Dr. Worden’s graduate students

5 attend the University of California Santa Cruz, where she is Adjunct Professor in the Ocean Sciences Department.

Dr. Worden’s research focuses on regulation of photoautotrophic microbes with an emphasis on carbon cycling in marine systems. This includes studies on the basic biology of eukaryotic microbes and how such studies can inform us about the evolution of eukaryotes, including land plants. Her group develops and implements methods and technologies for sea-going oceanography, including innovations in genomic, metagenomic and transcriptomic approaches. Dr. Worden is a Gordon & Betty Moore Foundation Marine Investigator and a Fellow of the Canadian Institute for Advanced Research.

LIONEL GUIDI LABORATOIRE D'OCÉANOGRAPHIE DE VILLEFRANCHE-SUR-MER

Lionel Guidi has been a CNRS researcher since 2013 in Villefranche- sur-Mer, one of the three marine stations of the Université Pierre et Marie Curie (Paris 06) in France. He graduated in 2008 from the Sorbonne Universités, UPMC, Université Paris 06, and Texas A&M University in Texas, USA. Shortly after graduation, he started four years of postdoctoral research at the C-MORE (Center for Microbial Oceanography: Research and Education) at the University of Hawaii. Guidi’s main research interests are driven by the need to better understand the global carbon cycle, and, in particular, the biological carbon pump, from gene to the ecosystem level. In order to achieve that goal, he had early motivation to bring “standard methods” together with new instruments and analytical tools to study the biology and biogeochemistry of the ocean. LEARN MORE

NEIL BANAS UNIVERSITY OF STRATHCLYDE

Neil Banas Is an oceanographer and mathematical ecologist, with a background in physical oceanography. His current organising questions are: first, given that climate change can push on a marine ecosystem by a dozen separate pathways simultaneously, which pathways are the crucial ones? Second, what is the role of biological complexity (diversity, adaptability, behavior, life history) in large-scale patterns in the ocean? Neil uses a range of dynamical model methods from high-resolution, spatially explicit simulations to paper-and-pencil sketches of life history and population dynamics. LEARN MORE

6 Abstracts

Ken Andersen feeding were determined from a literature review. The mechanistic trait-based approach to fish As with functional diversity and its functional Fish are the dominant aquatic organisms in the diversity indices, functional isotopic indices were body size range from about 1 g to 1 kg. Further, they calculated on the same principle to describe trophic are one of most diverse vertebrate groups with over diversity. Metrics take into account 26 known species. Their exceptional high functional/isotopic richness, functional/isotopic productivity support about 1% of global human diversity and functional/isotopic eveness. An consumption of protein with a value of about $1 analysis of the seasonal and interannual evolution bn/yr. Despite the huge functional and taxonomic of these metrics as well as the structure of the diversity among fish I will demonstrate that just community was performed to see how the three fundamental assumptions — metabolic interannual changes in benthic community scaling, scaling of clearance rate with size, and the structure in terms of species diversity and rule that big fish eat smaller fish — makes it functional diversity translate into changes in the possible to calculate the major relations relevant food web. for fish demography, community structure, and Poster Session 1 on Monday at 17.30. evolutionary ecology. These relations can be used in evolutionary ecology and to support practical Dominik Bahlburg management of fish populations and communities, Stefanie Moorthi, Bernd Blasius including fisheries induced evolution. In my talk, I Stoichiometric dynamics in a simple aquatic food will introduce the foundations of the trait-based web with implications for a changing Antarctic framework for fish. I will demonstrate the ecosystem applicability with examples and with a trait-based Rapidly increasing temperatures off the Western analysis of all fish species and an exploration of the Antarctic Peninsula (WAP) directly and indirectly differences between the two major groups, teleosts effect the complex network of geochemical, and elasmobranchs. Finally I will outline open physical and biological processes within the local questions and future applications and extensions of marine pelagic ecosystem. One of the proposed the framework. changes is a shift in the grazer community from Poster Session 2 on Tuesday at 17.30. Antarctic krill to the salp Salpa thompsoni with unknown consequences for the rest of the Lise Bacouillard ecosystem. This study focuses on the feedback of Raphaël Dupont, Céline Houbin, Cédric Leroux, internal macro-nutrient (N:P:C) composition of the Pascal Riera, Éric Thiébaut dominant grazer (Antarctic krill or Salpa thompsoni) Comparative evolution of functional diversity and on the external nutrient pool and consequently isotopic indices in the Bay of Morlaix phytoplankton stoichiometry in the WAP pelagic Functional diversity through functional traits food web. Experimental data, long-term field data analysis is an approach which is more commonly from the Palmer LTER as well as an NPZ-model used to evaluate the functional response of incorporating the effect of variable phytoplankton ecosystems to various natural and anthropogenic stoichiometry suggest that changes in macro- pressures. In parallel, the food web analysis by nutrient composition of the dominant grazer have stable isotopes also allows to study the functioning little effect on the phytoplankton macro-nutritional of ecosystems by focusing on the matter and energy composition. The data shows that concentrations of flows. These two distinct approaches can be bioavailable N and P are commonly very high in the complementary, describing in one hand the waters of the WAP throughout the entire growth theoretical trophic niche from biological traits season which theoretically enables phytoplankton related to the feeding mode of species, and in the to take up both resources with almost maximum other hand the realised niche from isotopic rates. Modifications of the supply ratio are then not signatures. The joint use of these two approaches reflected in the primary producer composition. has been tested on the multi-year food web Absolute external concentrations remain high and monitoring set up in 213 in the Bay of Morlaix at the other factors such as light or iron limit growth "Pierre Noire" station in the framework of the long- before macro-nutrients can be exploited. As a term monitoring program of the fine sand consequence, a shift from Antarctic krill to Salpa macrobenthic community established since 1977. thompsoni would have no notable effect on the This monitoring is based on the measurement of phytoplankton macro-nutrient stoichiometry. isotopic signatures (δ13C, δ15N) of (i) food sources, Poster Session 2 on Tuesday at 17.30. (ii) the 2-3 macrobenthos dominant species and (iii) demersal fish fauna. Biological traits related to

7 Neil Banas Melanie Bon Copepod life-history traits along Arctic Ocean Joao B. Gusmao, Maritza Fajardo, Jacques Grall, transport corridors: Scaling up from the lab to a Chris Harrod, Aldo S. Pacheco rapidly changing seascape Biological trait analysis for revealing macrobenthic Session B: Food-webs and Trophic Interactions functioning along a depth gradient from normoxia Keynote to hypoxia in the Humboldt upwelling system Decreases in dissolved oxygen (DO) concentration Joey Bernhardt is a key stressor in marine environments. When DO Anita Narwani concentrations fall below 2mL/L (i.e. hypoxia), The evolution of competitive ability in benthic organisms are particularly affected due to phytoplankton their limited capacity to move to well oxygenated Competition for limiting resources is one of the habitats. Hypoxia occurs naturally at shallow depths most fundamental ecological interactions, and has in some highly productive systems such as along the long been considered a key driver of biodiversity Humboldt upwelling ecosystem, particularly in patterns. Species' minimum resource requirements, South and Central Peru and Northern Chile. Such their R*, are key traits that link individual habitats are inhabited by opportunistic species physiological demands to the outcome of characterized by their small size, short life cycle, competition. Until recently, evolution was seen as a and little or no parental care. In order to better slow, varying constraint on species traits, rather understand how hypoxia affects the functioning of than a dynamic feedback mediating shifts in these benthic systems, macrobenthic functional abundance and the outcome of species diversity was studied along a gradient from shallow interactions. A key question remains unanswered -- normoxia to deeper hypoxia. Macrobenthos were to what extent are species’ competitive traits able sampled monthly at 1, 2, 3 and 5m depth between to evolve over ecological time scales? To address October 215 and October 217 in two sites of this knowledge gap, we tested the hypothesis that Mejillones Bay, Northern Chile. We found that competitive traits of phytoplankton are able to along a gradient from normoxia to hypoxia, feeding adapt in response to selection under resource modes switched from carnivore and herbivore, to limitation. Alternatively, there may be limits to filter and surface feeders, and then to subsurface adaptive trait evolution; for example if resource deposit feeders. In the deeper habitats with acute requirements for different essential resources (i.e. hypoxia, organisms were characterized by traits nitrogen or phosphorus) are genetically or such as reduced movement and body protection, as physiologically correlated. To identify potential well as asexual reproduction. In general, functional constraints on evolved competitive trait variation, richness were lower in deeper habitats and this we grew five populations of Chlamydomonas pattern was roughly maintained through the study reinhardtii for ~ 3 generations under seven period. However, in the deeper habitats of one of different environmental conditions. We quantified the site, macrobenthic functional richness and the minimum resource requirements of the divergence (using Rao’s Q based on abundance) ancestral and descendant populations and the showed a tendency to decrease with depth and potential for rapid adaptation to alter the outcome time. The results suggest a complete of competition. restructuration of the benthic trophic structure Session A: Traits, environments, ecology and driven by hypoxia with potential to affect local food evolution webs. Besides, the changes in the trait structure of Talk such benthic communities also suggests that bioturbation-mediated sediment processes might be affected. Poster Session 1 on Monday at 17.30.

8 B. B. Cael Pol Capdevila Nick Hawco, Siobhan Braybrook Maria Beger, Iain Stott, Patrick Barks, Gwilym A tale of two cobalts // Quantifying leaf cell shape Rowlands & Roberto Salguero-Gómez Cobalt (Co) is an important micronutrient in the Are marine species more resilient to global change ocean whose geochemistry is relatively poorly than terrestrial ones? characterized. In particular, the global turnover of Despite drastic loss of biodiversity during the last Co is not well-constrained as different processes decades, few documented extinctions exist in the have been argued to control this turnover that have marine realm when compared to terrestrial also been argued to operate on a wide range of ecosystems. The underlying causes of such timescales. Using corresponding radiocarbon differences in extinction rates remain unclear, measurements, we assign ages to a database of Co inevitably leading to the question “are marine and labile Co (LCo) concentration measurements. species more resilient to global change than We then use a regularized inverse Laplace terrestrial species?”. To address this question, we transform to tease apart the multiple timescales of used open-access databases including demographic Co turnover. Surprisingly, Co turnover is robustly information for over 4 marine and terrestrial best characterized by a relatively sharp, bimodal species from around the globe and across the tree distribution, with ~1/3 of Co turning over on a of life. To determine differences in the ~250a timescale and ~2/3 turning over on a ~1500a demographic resilience of marine and terrestrial timescale. LCo, which is independently measured species, we evaluated two components of and constitutes ~1/3 of total Co, is robustly resilience: (i) resistance to disturbances, and (ii) characterized by a relatively sharp, unimodel time to recovery. We also estimated the diststribution turning over on a similar multi- vulnerability of species to increases in centennial timescale. LCo is chemically similar to environmental variability and to changes in the Co2+ ion and is susceptible to scavenging by environmental autocorrelation, using stochastic Mn-oxidizing bacteria, whereas other Co is strongly elasticity analyses. Our results suggest that marine bound by organic molecules and inert. Thus, species do not show higher demographic resilience, somewhat surprisingly, it appears that the deep nor are more vulnerable to environmental change, ocean total Co inventory is well-described as than terrestrial ones. Instead, phylogenetic comprising two distinct pools, turning over on two relationships and environmental factors were more distinct timescales, potentially by distinct important in determining species’ resilience and mechanisms (e.g. bacterial scavenging & vulnerability to environmental change. ventilation). // Leaves’ epidermal cells display a Nonetheless, marine species’ population growth diversity of shapes, from regular and rectangular to rate was more sensitive to changes in complex and jigsaw-like. Understanding of the environmental autocorrelation than terrestrial function(s) as well as the phylogenetic or ones. Considering that climate change will alter the environmental patterns of cell shape arguably natural regimes of environmental fluctuations, remains elusive because of the unsatisfying shape these findings suggest that marine species may be metrics used to date. Drawing inspiration from even less resilient than terrestrial species to global potamology (river science), we argue that the change. Overall, our results do not support the natural shape metric is mean total absolute hypothesis that marine systems are more resilient curvature. This metric is surprisingly weakly than terrestrial ones, and indeed point towards the correlated with the more commonly used solidity opposite conclusion. metric for cells from hundreds of different plant Poster Session 1 on Monday at 17.30. species. We describe additional insight available from a curvature-based approach and discuss next steps. Poster Session 2 on Tuesday at 17.30.

9 Laura Cappelatti Emelia Chamberlain Alizée Mauffrey, John Griffin Hyewon Kim, Scott Doney, Jeff Bowman Applying continuous functional traits to large Leveraging microbial community structure data to brown seaweeds: variation across tidal emersion inform traits-based modeling, an approach based and wave exposure gradients on microbial community segmentation. A functional trait-based approach seeks a general Numerical modeling is a critical method for understanding of organism - environment understanding ecosystem processes. However, interactions, but, among primary producers, its current approaches are typically not informed by empirical basis rests on vascular plants. We microbial diversity data despite the rapidly growing hypothesised that with increasing intertidal availability of these data. One reason for this is that elevation, traits of large brown macroalgae would diversity data is high dimensional, with hundreds or reflect a resource-acquisition vs. conservation even thousands of variables defined for relatively (stress tolerance) trade-off at species and few time/space observations. This creates a community levels. Across the elevation gradient at discrepancy between the observed and modeled four UK sites of varying wave exposure, we: i) biological dimensionality that dramatically screened species’ relevant morphological traits, simplifies the diverse functionality of the microbial using principal component analysis to reduce community within the ecosystem. In Bowman et al. dimensionality; and ii) up-scaled species’ traits (217) we introduced a technique to “segment” the using community weighted trait means (CWMs). microbial community into functionally coherent The first principal component (PC1) strongly related units (“modes”) that can be described by a single to specific thallus area and thallus dry matter categorical variable. This categorical variable content, representing an acquisition - conservation reflects the key genetic traits of the microbial trade-off. Although species generally shifted to the community. From these genetic traits we can make conservative end of this axis as elevation increased, reasonable estimates of physiology (e.g., mid-shore Ascophyllum nodosum sat at the respiration, bacterial growth efficiency, cell size), extreme conservative end. PC2 associated with providing realistic initial conditions and a useful holdfast ratio, thickness and length, with A. “check” against parameter optimization with data nodusum scoring higher than other mid-shore assimilation. Here we describe a strategy for species. CWMs of PC1 decreased with elevation at implementing this approach with the Regional Test- two sites indicating a shift from ‘fast’ to ‘slow’ bed Model, a 1-D data assimilative ecosystem ecosystem functioning, but this relationship was model with parameters optimized for the pelagic disrupted by A. nodusum at the sheltered site, and western Antarctic Peninsula near Palmer Station. In by the up-shore extent of Laminaria digitata at the a recent analysis of 16S rRNA gene data from a 5- most exposed site. The anomalous traits of A. year time-series of the region, we identified 8 nodusum reflect its unique competitive strategy recurrent modes in the bacterial community. (slow, persistent growth) in the relatively stressful Estimates of genome parameters estimated for mid-shore. Seaweed functional traits show promise each mode showed logical temporal trends in 16S in linking species’ identities to their strategies and rRNA gene copy number, genome size, and GC ecosystem contributions. However, because content. From these parameters we can make resource conservation traits can be related to reasonable estimates of 1 key bacterial parameters competitive as well as stress tolerance strategies, in the model. During a model hind-cast of the time predicting seaweed trait responses to series, we will compare parameter estimates environmental stress gradients is challenging. derived from data assimilation with our estimates Poster Session 1 on Monday at 17.30. for the observed mode. When the difference in parameter estimates exceeds a threshold, the model can be “corrected” to match the observed mode and the time-point flagged for further investigation. Ultimately, we expect this approach to improve the fidelity of traits-based ecosystem models, leading to a better understanding of complex ecosystem processes. Poster Session 2 on Tuesday at 17.30.

10 Samuel Chan Chris Clements Huang Danwei Trait-based signals of collapse and recovery Long-term monitoring reveals decline in trait- Predicting population declines is a key challenge in based functional diversity on coral reefs in the face of global environmental change. One Singapore potentially powerful approach to achieving this is to Long-term monitoring of coral reefs in Singapore use shifts in fitness-related phenotypic traits such has revealed changes in both live coral cover and as body size as predictors of the response of diversity over time driven mainly by coastal populations to future stressors. Here I will detail reclamation, shipping and industrial activities. Data recent work which has demonstrated how trait from these studies have only been used to examine shifts can be used as early warning signals of community diversity and assembly in terms of approach population collapse, as well as species richness, which may not fully encapsulate community recovery, with a particular focus on differences among communities. Based on a 3-year marine systems. reef monitoring dataset, we investigate temporal Poster Session 1 on Monday at 17.30. and fine-spatial patterns of taxonomic, phylogenetic and trait-based functional diversity Larry Crowder measures for reef-building corals. Our analyses Elliott L. Hazen, Stephanie J. Green, Natasha A. reveal that while most diversity metrics have Hardy remained relatively stable, the observed decline in Oceanic Predators under Climate Change: functional diversity through time may highlight Changing Distributions and Dynamic Trophic losses of particular reef functions. The temporal Connections in the California Current change is examined in the context of the small The California Current provides an excellent spatial separation among Singapore’s reefs, over opportunity to enhance our understanding of the which we detail divergences in trait diversity role of climate factors in the changing distributions trajectories that may be related to specific of pelagic predators. These changing distributions environmental drivers. This trait-based diversity have been documented empirically in response to assessment thus offers the most consistent both short term (El Nino/La Nina) climate variation evaluation of the general decline that is apparent and longer term environmental changes along the on the urbanised coral reefs of Singapore. Pacific coast. Current food web models involving Poster Session 1 on Monday at 17.30. these predators tend to be temporally or spatially limited and often frame trophic connections based Bingzhang Chen on sparse and dated diet data. A traits-based D.J.S. Montagnes approach to these trophic interactions should allow Thermal diversity affects responses of us to better understand and manage emerging food phytoplankton community to warming webs under climate change. We have modeled In order to reconcile the apparent dichotomy responses of pelagic predators to fixed and dynamic between the intra- and inter-specific activation features using dynamic habitat models that link energy and scale up from individual temperature remotely sensed oceanography and satellite performance curves to the community level, we tracking data to forecast distributions and seasonal propose to use optimal temperature as the master movements of these animals relative to thermal trait to model the temperature responses environmental variation. This research has allowed of each species and the distributions of the thermal us examine the spatial and temporal dynamics of traits of the community. We parameterize the protected species relative to bycatch in fisheries model using a global dataset of phytoplankton and to ship strikes. We have also extended this growth rates, in which significant thermal work to forecast the changes in distribution and compensation is observed. Both the intra- and habitat volume of 15 pelagic predator species over inter-specific activation energy can be well the next century. Although these approaches can be incorporated into the theory. The model powerful and foster the possibility of dynamic simulations suggest that the community level ocean management, the models are currently activation energy is affected by the diversity of the limited by the lack of a robust approach to novel thermal trait, which also indirectly influences trophic connections. community mean optimal temperature. We Poster Session 2 on Tuesday at 17.30. propose that the community level activation energy may not be a static quantity and urge that distributions of optimal temperature of natural plankton communities ought to be made. Poster Session 2 on Tuesday at 17.30.

11 Stephanie Dutkiewicz Brian Enquist Phil Boyd and Ulf Riebesell The past, present, and future of trait-based Biogeochemical and ecological redundancy in ecology: Toward a more predictive framework phytoplankton communities Session A: Traits, environments, ecology and Global change driven stressors such as warming, evolution ocean acidification and alterations to resource Keynote supply are likely to have differing effects on the diverse set of phytoplankton species. Differing Emile Faure responses are likely to lead to extinction of some S.D. Ayata, L. Bittner species. Here we explore how losses of species, and From genes to functional traits in the global ocean: their specific traits, might impact the marine building de novo plankton functional types from biogeochemistry and ecology. We use a global environmental metagenomics data three-dimensional model that includes functional One global challenge of the 21st century is to and size traits to capture complex regional diverse understand and predict the impacts of anthropic planktonic communities. The communities climate change on ecosystem functioning. In the encompass size classes from .6 to over 2um, and ocean, planktonic organisms play a crucial role in several functional groupings (e.g. diatoms, climate regulation, global biogeochemical cycles, diazotrophs) and trophic strategies. We run a series and marine trophic networks. Models coupling of experiments where we remove a single size class, physics and biogeochemistry are a widely used tool functional group or combination of phytoplankton to quantify biogeochemical cycles through the types to explore redundancy in phytoplankton simulation of planktonic ecosystems dynamics. But communities. We find that removing nitrogen fixing these models often rely on a biogeochemical view phytoplankton has the largest impact on of marine plankton, since they describe dynamics of biogeochemical properties such as global primary functional groups historically described by marine production. However, interestingly, we find that biogeochemists (known as Plankton Functional removing size classes and functional groups (other Types, or PFT). These groups have been criticized than diazotrophs) has little impact on globally for their lack of ecological justifications, potentially integrated primary production, but many of the leading to an oversimplified representation of experiments do show large regional shifts in planktonic diversity in models. However, the lack of biogeochemsitry. We also find non-intuitive data-driven methodologies to determine and ecological changes, with shifts in the rest of the quantify the potential and realized functional traits communities and large impacts on higher trophic of planktonic communities still prevent marine levels in almost all experiments. Our results suggest ecosystem modelers from implementing a lack of ecological redundancy, though potentially realistically diverse planktonic communities into more biogeochemical redundancy, but only when models. Here, we addressed this problem by placed in a global context. building de novo plankton functional types from Session E: Biodiversity and ecosystem function metagenomics data. More precisely, we used a set Talk of 885 procaryotic metagenome-assembled genomes (MAGs) built from the Tara Oceans Kyle Edwards metagenomics data by a precedent study. For each Grieg F. Steward, Christopher R. Schvarcz of these MAGs, we detected and translated gene Size as a master trait in viral ecology domains to protein sequences, and gathered the Body size is often called a 'master trait', due to the genes relative abundance in the Tara Oceans pervasive effects of size on metabolic rates, samples. A sequence similarity network was then predator-prey relationships, biomechanics, etc. built to create groups of homologous proteins that Viruses vary substantially in size (~5-fold in potentially participate to the same metabolic diameter and ~1-fold in genome size), but the pathways. The functional annotations of these sets selective forces that drive the origin and allowed to define groups of proteins linked to maintenance of viral size diversity are poorly biogeochemical functions, e.g. photosynthesis or understand. Here we develop theory and synthesize nitrogen fixation. We investigated the distribution data for key virus traits and how they scale with of each of these sets across the global Ocean in virus size, to consider the fitness advantages of perspective of the environmental conditions.. small vs. large size and how these may be selected Session 5: Traits, Networks and Ecosystem for under different conditions. Function Poster Session 1 on Monday at 17.30. Talk

12 Øyvind Fiksen Christopher Follett Nadia Fouzai, Anders F Opdal, Christian Jørgensen Matthew J. Church, Stephanie Dutkiewicz and Dying from the lesser of three evils - facilitation Michael J. Follows and non-consumptive effects emerge in a model Geometric Niche Partitioning of Nitrogen-Fixers in with multiple predators the Sea Prey modify their behaviour to avoid predation, but Nitrogen fixing organisms play a key role in dilemmas arise when predators vary in hunting alleviating nitrogen limitation and stimulating new style. Behaviours that successfully evade one production in oligotrophic regions of the global predator may reduce foraging or facilitate exposure ocean. Shifts in the elemental ratio of resource to another predator, forcing the prey to choose the supply help explain the biogeography of nitrogen lesser of two evils. Theory therefore separates fixation, but the factors which control the between direct (or consumptive) effects of a functional class of nitrogen fixer (Diatom- predator and all the indirect consequences (or non- Diazotroph Associations, Trichodesmium, UCYN-A, consumptive and trait-mediated indirect effects) Crocosphaera) remain poorly understood. Focusing the predator incurs. We model optimal behaviour on the generation, diffusion and reduction of of Atlantic cod Gadus morhua larvae in a water oxygen, we use the trait of cell size to derive a cap column, and find the minimal vulnerability to three on the growth efficiency of multi-cellular, nitrogen groups of predators with different hunting modes. fixing, consortia. We find that under certain The predators are: i) ambush predators that sit-and- conditions, this maximum efficiency depends wait for approaching fish larvae; ii) cruising entirely on the relative sizes and locations of fixing invertebrates that eat larvae in their path; and iii) and non-fixing cells. This geometric theory correctly fish which are visually hunting predators. We use a predicts the temporal and spatial niche partitioning state-dependent model that finds optimal between UCYN-A and Crocosphaera as behaviours (vertical position and swimming speed) demonstrated by 1 years of monthly nifH gene under any given exposure to the three distinct abundance data at Station ALOHA, an oligotrophic modes of predation. We then vary abundance of time series site in the oligotrophic Pacific Ocean. each predator and quantify direct and indirect We further explain how this geometric efficiency effects of predation. The nature and strength of factor could be straightforwardly encoded in direct and indirect effects varied with predator type computational, trait-based, models. When and abundance. Larvae escaped about half the combined with previous work, this theory provides mortality from fish by swimming deeper to avoid a blueprint for understanding the unique size light, but their activity level and cumulative structuring of nitrogen fixing consortia and their predation from ambush predators increased. When spatial-temporal structuring in the oligotrophic sea. ambush invertebrates dominated, it was optimal to Session C: Multifarious lifestyles of marine be less active but in more lit habitats, and predation microbes from fish increased. Against cruising predators Talk there was no remedy. In all cases, the shift in behaviour allowed growth to remain almost the same, while total predation were cut by one third. In early life stages with high and size-dependent mortality rates, growth rate can be a poor measure of the importance of behavioural strategies. Session B: Food-webs and Trophic Interactions Talk

13 Bethany Fowler, Ursula Gaedke M.G. Neubert, K.R. Hunter-Cevera, A.R. Solow and Elias Ehrlich, Ruben Ceulemans, Toni Klauschies, H.M. Sosik Christian Guill One Million Matrices: Size-structured modeling The role of trade-offs and mutual trait adaptation reveals in situ phytoplankton dynamics. across three trophic levels: Evidence from a The picoeukaryotes are an abundant and diverse natural plankton food web and simulation models group of marine photosynthetic plankton. Functionally diverse, multi-trophic communities Understanding their population dynamics is key to can adapt to altered environmental conditions. This understanding the role they play in the marine food may strongly feedback to their trait diversity and web and in global biogeochemical cycling. population dynamics in which trait changes on one Phytoplankton vital rates are difficult to quantify in trophic level can cascade towards the others. situ due to their large population sizes, short Theory predicts that the shape of trade-offs generation times, and high mortality from viral lysis between traits crucially affects these trait and zooplankton grazing. Building from the work of dynamics, but field evidence is rare. The talk will Sosik et al. (23), we fit a matrix population model to cover three main aspects: (1.) We show how the a 14-year time series of observations of individual shape of a defense-growth trade-off in cell traits, including size and pigmentation. Using phytoplankton governs seasonal trait dynamics the model, we are able to 1) identify apparent using high-frequency, long-term measurements populations within the picoeukaryote assemblage, from Lake Constance. We observed a concave 2) estimate rates of cell division and loss and 3) trade-off curve and a dominance of relatively fast- investigate how those rates change over time. We growing species with intermediate defense levels . find that the picoeukaryotes at Martha's Vineyard The pronounced seasonal changes in selective Coastal Observatory follow a strong seasonal cycle, forces were clearly reflected by changes in the trait with division rates ranging from an average of .1 distributions. By combining data and modelling, we /day in January to 2.1 /day in August. Division and show that low fitness differences can promote loss rates are seen to be closely coupled throughout maintenance of phytoplankton trait variation along the year and to increase with increasing sea surface the trade-off curve. (2.) We demonstrate how such temperature in the spring. Over the 24-hour cycle, temporal trait changes alter the ecological loss rates are not constant, and our analysis dynamics across the first three trophic levels in the suggests that the picoeukaryotes may be food web of Lake Constance. Phytoplankton and preferentially grazed or subject to viral lysis during herbivorous and carnivorous zooplankton all daylight hours. This work demonstrates that our exhibited mutually interacting biomass-trait population model can be usefully applied to feedbacks. The observed temporal order of trait heterogeneous phytoplankton groups and can be a changes between herbivores and primary powerful tool for studying their ecology in a natural producers was counterintuitive and only explicable system. by accounting for trait changes in the carnivores. Poster Session 2 on Tuesday at 17.30. (3.) To generalize our understanding of trait variation in tritrophic systems, we modelled how adding gradually trait variation to each trophic level influences population and community dynamics. We show that trait variation enhances resource use efficiency, productivity, stability, and resilience of the entire food web. Examining the phase relationships between different species both across and within trophic levels revealed how top-down or bottom-up control affects biomass production, and how compensatory dynamical patterns between functionally different species affect community variability. Session C: Multifarious lifestyles of marine microbes Talk

14 Irene Gallego Nogales behavioural and morphological traits play— Anita Narwani independent from species identity—in determining Phytoplankton Trait Evolution under Resource the strength of predator-prey interactions, which Limitation: An In-Lake Mesocosm Experiment structure the flow of energy through communities. The high genotypic diversity and turnover observed We use this synthesis to develop a framework in over space and time in marine and freshwater which foraging interactions occur between species phytoplankton populations suggests that rapid based on their trait typologies, rather than evolution occurs in natural phytoplankton taxonomic identity. Such an approach facilitates populations, but the role of competition in general mechanistic predictions can be made about drivingevolutionary change in these populations is the interaction strengths between species that do unknown. While lab studies have considerably not co-occur now, but are likely to in future. We advanced our understanding of eco-evolutionary outline ecosystem characteristics for which a dynamics, they have some limitations as most predator-prey traits approach could greatly aid in experiments use only single species or very forecasting species redistribution, identify data simplified “communities”, neglecting any effect of needs and analyses for testing and validating the complex community structures. Given these approach, and illustrate its application to two limitations, we aim to investigate adaptation to marine case studies in the tropical Western Atlantic competition in natural phytoplankton populations. and temperate Eastern Pacific in which the Using in situ lake mesocosm experiments in Lake ecological consequences of rapid predator Greifensee (Switzerland), we will manipulate the redistribution are understood through the identity of the primary limiting resource (N, P or application of a trophic traits framework. light) and track changes in community structure, Session E: Biodiversity and ecosystem function species traits, and population-level genotypic Talk diversity. We will also testwhether changes in community structure occur due to changes in Maria Grigoratou individual species’ traits or due to changes in the Fanny M. Monteiro, Jamie Wilson, Andy Ridgwell identity and associated traits of dominant species. and Daniela N. Schmidt The contribution of evolution to trait change will be Exploring planktonic foraminifera ecology in quantified by measuring associations between the present and future climate conditions using a size- degree of trait change within a certain population structured ecosystem global ocean model and changes in population genotypic structure. Planktonic foraminifera are main zooplankton Poster Session 1 on Monday at 17.30. calcifiers, contributing to 23-56% of the modern total pelagic carbonate production. Adult species Stephanie Green are categorized into two groups; herbivorous non- Natasha A. Hardy, Larry B. Crowder spinose and carnivorous spinose. Here we A traits-based framework to account for the developed the first global trait-based ecosystem influence of predator-prey interactions on species model of planktonic foraminifera, ForamEcoGEnIE, distribution under global change to investigate in combination with observations, The distribution and abundance of species across the ecology and biogeography of non-spinose our globe is changing at an unprecedented rate due adults in present and future climate scenarios. The to human-mediated processes such as climate trait-based model accounts for the traits of change, biological invasion, and exploitation- calcification, size and feeding behaviour. Our model mediated population decline and recovery. As a suggests an energy penalty of calcification result of these global change forces, novel equivalent to a 10% reduction of the growth rate, combinations of species are now co-occurring—and and a benefit of calcification represented by a 30% interacting—for the first time. How will the reduction in background mortality. This would structure and function of ecosystems, and the indicate a potential important role of the shell to socio-economic benefits they provide, respond to protection from pathogens. The model captures the changing species composition? Reviewing studies of observed seasonal and annual distribution of non- species’ range and abundance change reveals that spinose species with maximum abundance in the much of the effort thus far has focused on the role subpolar, temperate and upwelling regions and traits play in conferring information about abiotic minimum in subtropics and tropics. We find that requirements and dispersibility in response to global warming has a strong impact on planktonic environmental change. However, a key challenge foraminifera with an overall reduction of their for forecasting species distribution under global stocks which potentially can be associated with a change is a lack of general principles from which to major decrease in the ocean CaCO3 production. predict the strength of novel species interactions as Poster Session 2 on Tuesday at 17.30. they emerge within re-assembled systems. Here we synthesize evidence for the pervasive role

15 Josephine Grønning determine what further insights traits might Thomas Kiørboe provide to understanding changes in ecosystem Grazer induction of shell-thickening in diatoms functioning over time. Traits identified in a previous When exposed to predators, many phytoplankton systematic review as both response and effect traits species increase their defense; e.g. toxin were used to build a functional space. General production, reduction of chain length, Additive Models were used to assess the changes in bioluminescence, etc. The silicified cell walls of individual traits and functional diversity over time. diatoms are believed to serve as a defense towards Results indicate an increase in functional diversity grazing and experiments have shown that thin- over time with protection and the immediate shelled cells are grazed less upon by insignificant impact of climate change is mesozooplankton than thick-shelled ones. demonstrated. Increasing body size in protected Moreover, one experiment has indicated, that areas over time contributed to rates of increase of diatoms exposed to chemical cues released from key feeding groups of fish. Such shifts in the herbivores become significantly more silicified than functional space of coral reef fish over time will ones not exposed. To investigate this inducibility of likely have an impact on key ecosystem processes silicification in diatoms, we exposed 7 different such as herbivory and predation, as such processes diatom species to waterborne copepod cues in are directly dependent on traits including size and induction experiments. We measured the diet. By applying a response and effect trait population growth rate and silica content per cell framework to this dataset, the impacts of volume and found no difference in those two disturbances and management on ecosystem parameters between induced and non-induced functioning is illustrated. cells. Hence we found no indication that any of the Poster Session 1 on Monday at 17.30. tested diatom species can upregulate their defense in the presence of grazers. All experiments of this George Hagstrom study were conducted under non-limited conditions Trait-Based Models of Phytoplankton with respect to temperature, light and nutrients. Stoichiometry: Nutrient Uptake, Environmental Therefore, future experiments should test the Drivers, and Genomics. inducibility of silicification of diatoms cells under Trait-Based models have helped reveal how resource limited conditions. environmental conditions control phytoplankton Poster Session 2 on Tuesday at 17.30. elemental stoichiometry. Despite these successes, limitations to our data and our understanding of Lionel Guidi physiology have prevented us from modeling the High-throughput sequencing and imaging: New trade-offs between different nutrient uptake traits, avenues for trait based modeling? the effect of limitation by different nutrients on Session D: Traits, Networks and Ecosystem elemental stoichiometry, and from distinguishing Function the effects of environmental co-variates like Keynote temperature and the nutrients. Here we develop a new trait-based model of phytoplankton Jeneen Hadj-Hammou stoichiometry which captures investments in the Timothy McClanahan, David Mouillot and Nicholas uptake of different types of N, P, and Fe, and thus Graham predicts the effects of different types of nutrient Comparing taxonomic and functional changes of limitation on phytoplankton stoichiometry. We coral reef fish over time in protected areas parametrize this model in a Bayesian framework Coral reef fish are increasingly confronted with a using a new, high quality dataset and show how the range of environmental disturbances. However, resulting model revises our understanding about they also contribute to crucial ecosystem processes the roles of N, P, Fe, and temperature in the and services in a number of ways. Functional traits regulation of stoichiometry. Lastly, we discuss how and corresponding metrics of functional diversity this framework can be extended to incorporate provide a mechanistic link between species and 'omics data derived from both field work and their responses to disturbances and effects on experiments. processes. They provide different insights into how Session D: Traits, Networks and Ecosystem future ecosystems might function and deliver Function ecosystem services to the people dependent on Talk them. A long-term chronosequence dataset spanning 4 years of fish and benthic monitoring data from Kenyan coral reef Marine Protected Areas has previously been analysed using taxonomic-based time-series approaches. We apply a trait-based approach to the same dataset to

16 Natasha Hardy Chris Hill Will Figueira, Elliott Hazen, Larry B. Crowder, Oliver Jahn, Steph Dutkiewicz, Zhen Wu, Greg Stephanie J. Green Britten, Ali Ramadhan Trait-based frameworks for understanding Sub-mesoscale induced variability in trait based predator-prey interactions along gradients of ecosystem models ecological change from the coast to the open This talk will look at a suite of emerging activities ocean aimed at examining how state of the art trait based Species distributions and interactions are rapidly models based on the MIT Darwin ecosystem code changing in response to increasing human-induced and algorithms respond to physical ocean model drivers of environmental change, including variability at spatial scales down to below 1 overexploitation of resources and climate change. kilometer and at temporary scales that capture the Novel combinations of species are giving rise to new diel cycle. The talk will describe some initial results trophic dynamics within communities, and large- from a family of models and will look at ways we are scale changes to the structure and function of trying to synthesize the rather complex systems altered ecosystems. We examine trends in marine into big picture insights. It will discuss current predator-prey interactions in a series of case dilemmas on how to appropriately interpret studies of changes in predator population and classical ecosystem statistical methods such as distribution from across the Pacific Ocean: the rapid Bray-Curtis diversity and Shannon index in the recovery of large coastal predators following context of a moving, Lagrangian frame of reference federal protection of previously harvested species; with potentially vigorous physical mixing present. and, large-scale spatial and temporal shifts in the Poster Session 1 on Monday at 17.30. distribution of large oceanic predators in response to warming and increased variability in Helmut Hillebrand oceanographic habitats. We illustrate the relevance Charlotte Kunze of a trait-based framework for understanding shifts Functional traits explaining species-specific and in trophic interactions between predators and community wide responses to disturbances complex prey communities in changing ecosystems. Resistance to and recovery from pulse disturbances We use a fourth-corner modelling approach to are two dimensions of ecological stability that have analyzing statistical relationships between multiple been addressed in a broad range of global change arrays of data and to assessing the power of trait- experiments. Here, we use this existing literature in based analyses for predicting changing ecological a meta-analyse to ask i) how much functional and interactions. Analytical tools that incorporate compositional stability are connected to each and predictive traits informing the predation process ii) whether each form of stability is related to (the will add salient and cost-effective information to same) traits of component species. We use a existing species distribution and ecosystem-based recently published method to decompose models, such as identifying key groups of prey that responses to pulse disturbances and apply it to a are being exploited by predators in changing cross-system database currently consisting of ecosystems, or for example in identifying spatio- several hundred experiments. We find strong temporal shifts in ecological interactions. This correlations between different aspects of stability, information can be communicated to and applied which are linked to differences in experimental by managers, responsible for achieving physical setup and organisms traits. objectives for conservation and mitigation of Poster Session 1 on Monday at 17.30. human impacts with finite resource budgets. As climate change is shifting fisheries resources across jurisdictional boundaries, our team hopes to foster international collaborations on predator diet data to produce predictive tools for predator-prey interactions across gradients of environmental change. Poster Session 2 on Tuesday at 17.30.

17 Nils H. Hintz Pei-Chi Ho Poelman Y., Wacker A., Striebel M. Chun-Wei Chang, Fuh-Kwo Shiah, Pei-Ling Wang, Phytoplankton response to changing light Chih-hao Hsieh, Ken H. Andersen spectrum Body size, light intensity and nutrient supply Light is considered as key driver of energy and determine plankton stoichiometry in mixotrophic material flow on earth. In aquatic systems the light plankton food webs availability for photosynthetic organisms rapidly Trophic strategy determines stoichiometry of decreases with water depth and thus limits plankton. In general, heterotrophic zooplankton phytoplankton growth and primary production. and mixotrophs have lower and more homeostatic Besides the general decrease in light intensity, the C:N and C:P ratios than photoautotrophic spectral composition of the available light also phytoplankton. Body size may be the key trait changes. Different findings proof that light cannot influencing the development of trophic strategy only be considered as a single resource for and thus plankton stoichiometry: resource (light, phytoplankton but as a multitude of resources in inorganic nutrients, and food particles) uptake terms of spectral quality. To utilize different parts rates depend on body size. Here, we measured of the light spectrum, phytoplankton taxa possess plankton size-fractionated C:N ratios under diverse accessory pigments in addition to different intensities of light and nutrient supply in chlorophyll a in specific combinations and subtropical freshwater and marine systems. quantities. Therefore, different phytoplankton Furthermore, to determine the biological species with specific light-utilization traits can mechanisms that critically shape plankton trophic harvest the available light complementary, which strategy and stoichiometry, we constructed a enables coexistence and a higher diversity. To plankton food web model in which the affinities to estimate effects of different spectral qualities on light, inorganic N nutrient and food particles of an single phytoplankton strains as well as a natural organism allometrically scale with its body size. We North Sea community three different light colors found a unimodal body size-C:N ratio pattern with (red, blue, green) as well as the full control a maximum C:N ratio at 44-74 μm and 5-14 μm spectrum (white) at the same irradiance level were diameter in freshwater and marine systems. tested. We conducted small (up to 200 mL) and Moreover, the change of C:N ratio with light and large-scale (600 L mesocosms) experiments and inorganic nutrient is the largest at 44-74 μm monitored species composition-, pigment- and freshwater phytoplankton size class. These patterns nutrient (stoichiometry) analysis. We expected the are reproduced by our model simulation: C:N ratio monocultures to respond species-specifically in of photoautotrophs (≤ 51μm) increases with body both, growth rate and changes in pigment size, and C:N ratios of mixotrophs (≥ 71μm) composition. For example, cyanobacteria decrease with increasing heterotrophy due to low performed better at green light than diatom or photoautotrophic C gain and high respirational C green algae and exhibited a relative increase in loss. We also found that C:N ratio change with light pigments absorbing the green part of the light and inorganic nutrient is the largest at size class 51 spectrum. Within the natural communities we μm, corresponding to the observations in the expected pigment composition to change prior to freshwater system. Based on our field observations changes in species composition. Our results and simulation, size-dependent trophic strategy indicate responses of the phytoplankton and respiration are critical to plankton communities to light quality on the short- and long- stoichiometry. term scale. The specific utilization of the light Poster Session 2 on Tuesday at 17.30. spectrum enables coexistence of species under the full light spectrum but competitive exclusion occurred under constrained light spectrum conditions. This is important in understanding phytoplankton biodiversity under changing light conditions. Poster Session 2 on Tuesday at 17.30.

18 Rucha Karkarey Kasia Kenitz Mahesh Sankaran, Mayuresh Gangal, Elrika Eric C. Orenstein, Paul L.D. Roberts, Peter J.S. D'souza, Teresa Alcoverro and Rohan Arthur Franks, Jules S. Jaffe, Melissa Carter, Andrew D. Habitat degradation over a decadal scale drives Barton functional shifts in mesopredatory coral reef fish Environmental and ecological drivers of variability assemblages in chain-forming marine diatoms Climate-change is rapidly degrading the structural Colony formation is common among marine complexity of ecosystems which is unraveling phytoplankton, yet little is known about abundance habitat-associated species assemblages. patterns and fitness of colonies relative to Understanding how changes in biodiversity is competing taxa. Particularly, formation of chain- impacting ecosystem function is an urgent like colonies in diatoms has important implications imperative. On coral reefs, benthic mesopredatory for diatom growth, survival and carbon transfer. We fish represent a guild of closely competing species, used supervised machine learning to distinguish with widely divergent life-history traits and diatom chains from 6 million images of suspended susceptibility to habitat degradation. particles and organisms taken by the Scrips Mesopredators can play critical functional roles on Plankton Camera System, an underwater reefs by either directly consuming prey or by microscope which images particles in situ without modifying prey behaviours, yet few studies have mechanically disturbing them. Using a novel, high- explored how changing mesopredator assemblages resolution time series generated by automated are likely to affect ecosystem function. We tracked classification of underwater images, and changes in reef structural complexity and observations using traditional microscopy, we mesopredator fish assemblages since 1998, in the identify environmental drivers underlying temporal lightly fished Lakshadweep archipelago, Indian variability of chain-forming and single-cell diatoms Ocean. Based on our long-term data from twelve off the coast in Southern California Bight. Lower permanent monitoring sites across three islands, abundances of diatom chains were recorded during encompassing three mass-bleaching disturbances anomalously warm and more stratified period, (1998, 21, 216), we studied how a loss of habitat compared with the cooler part of the record. structural complexity impacts the taxonomic and Diatom blooms were dominated by chain-formers, functional diversity of mesopredators (12 species, whereas single-cell diatoms prevailed during low- 15 families). Reefs that remained structurally intact biomass conditions. We hypothesize that nutrient- since 1998 declined rapidly after 21. In these reefs, limited conditions are dominated by better nutrient we found no significant changes in mesopredator competitors, whereas species best adapted to biomass, density and richness but a significant shift escape predation from microzooplankton form in species composition since 21. We used five blooms. Our results show that single-cell and chain- commonly measured fish traits (maximum body forming diatoms have contrasting ecological size, diet, mobility, water-column position and dynamics driven by both bottom-up and top-down foraging strategy) to functionally classify the ecological processes. species. These traits are proxies for two important Session C: Multifarious lifestyles of marine mesopredator functional roles: food acquisition microbes and locomotion, that are likely impacted by habitat Talk structure. Functional diversity of mesopredators was quantified using four indices - richness, evenness, divergence and specialization. Most interestingly, we found a two-fold increase in ‘functional divergence’ and a three-fold increase in ‘functional specialization’ since 21. This functional shift can be attributed to an increase in the abundance of species with a particular combination of traits that appear to be favoured in structurally degraded reefs (ie., large body size, high mobility, omnivorous diets, flexible foraging modes and bentho-pelagic habits). Shifts in mesopredator assemblages from small, site-attached, ambush predators to large, widely-ranging, roving predators likely represent major shifts in predation and associated ecosystem function which need to be addressed further. Poster Session 1 on Monday at 17.30.

19 Christopher Klausmeier filamentous potentially toxic cyanobacteria, with Thomas Koffel, Kaito Umemura, Elena Litchman high surface/volume ratios, developed most in high Trait-based approaches to species abundance nutrient and temperature treatments. However, distributions different species with similar morphological traits Species abundance distributions (SADs) are an alternatively dominated or coexisted, presenting intermediate-level description of the diversity in a similar fitness which was estimated as R* using community. Studied by ecologists for over a individual morphological traits and literature hundred years, SADs are seen as an example of a reviewed scaling relationships. In experiments general law in ecological communities: few species defined by same environmental conditions (high are common while most are rare. More precise resources and temperature), were MBFG III descriptions have been suggested, such as the dominated, the invasion of the cyanobacteria lognormal distribution, but appreciable variation Cylindrospermopsis raciborskii (belonging to MBFG exists. Over 25 theories have been put forward to III) was successful, but its relative abundance varied explain SADs, but most are unconnected to among replicates. Community metagenomic population dynamics. Here we present a trait-based analysis evidenced that despite the observed theory of SADs in open systems subject to changes in specific composition of both autotrophic immigration. We find that these models readily and heterotrophic microbial communities, main generate realistic SADs where species abundance functions remained similar among treatments. This varies over orders of magnitude, but no universal suggests that MBFG do indeed contain functionally distribution emerges. Instead, the details of the equivalent and interchangeable species. In line with SAD depend on local selective forces and regional the emergent neutrality theory, this means that patterns of abundance. Species can be selection from the species pool is acting on dichotomized as "core species" that would persist functional groups and the identity of a particular in the absence of immigration and "satellite species within such groups could be essentially a species" that require immigration for persistence. stochastic process. The application of trait-based Core species dominate ecosystem functioning, but approaches to summarize the niche and estimate satellite species provide adaptive capacity in fitness changes along environmental gradients was changing environments. useful to evaluate underlying mechanisms and Poster Session 1 on Monday at 17.30. predict microbial invasion success. Comparing present framework to those used in the marine Carla Kruk realm is straightforward and could provide C. Piccini, G. Beamud, L. Sampognaro, F. Lepillanc, benchmarks to find gaps and opportunities to A.M. Segura advance into a comprehensive trait-based aquatic Predictable species coexistence mediated by ecology. functional equivalence Poster Session 1 on Monday at 17.30. Morphological traits are useful to investigate phytoplankton dynamics and community assembly both in freshwater and marine environments. Historical divergence in the approaches requires an effort to synthesize paradigms and reach an unified framework. Here, we use a morphology-based functional groups (MBFG) approach and show that community structure and coexistence of species depends on organisms traits related to ecological and functional aptitude. Our hypothesis is that species with similar functional traits, organized in functional groups have similar niche. Within each functional group, species are relatively equivalent and therefore functionally interchangeable. We predict successful invaders will be species of the same functional group with equal or higher fitness than resident species.To evaluate these hypothesis we analyzed the temporal succession of phytoplankton species retrieved from several natural communities (species pool from lakes in a subtropical region) under different nutrient and temperature levels emulating subtropical shallow oligotrophic and eutrophic lakes in winter and summer.Total phytoplankton and particularly large

20 Suzana Leles was independent on the number of species, but Luca Polimene, Jorn Bruggeman, Jeremy Blackford, influenced by the identity of dominant taxa and Stefano Ciavatta, Aditee Mitra, Kevin John Flynn their sensitivity to salinity fluctuations. Our study Mixotrophy and the succession of plankton trophic emphasizes that the response of local ecosystem strategies within ecosystem models productivity to environmental change will not Carbon acquisition among plankton is usually simply depend on local species richness, but on the assigned to one of the two trophic strategies: entire set of interactions within communities. autotrophy or heterotrophy. In reality, many Session E: Biodiversity and ecosystem function plankton combine both strategies; these are called Talk mixotrophs. Mixotrophy is widespread among protist plankton displaying diverse functional forms Christian Lindemann across a wide range of sizes. Mixotrophs are Scaling buoyancy regulation in marine diatoms distinguished between those with innate capacity Diatoms are an important part in the marine for photosynthesis (constitutive mixotrophs, CMs) ecosystem, contributing as much as 4% to the and those which acquire phototrophy from their marine carbon uptake. Due to the absence of prey (non-constitutive mixotrophs, NCMs). flagellum or cilia they are often modeled as However, little is known about the niches of passively sinking particles, where the sinking different mixotrophs and how they may affect velocity is determined by the cell size. However, biogeochemistry and trophodynamics in marine many diatom species exhibit variable sinking rates ecosystems. Here we explored these dynamics not only with changes in cell size, but driven by using a plankton food web model describing diverse active buoyancy regulation through changes in cell forms of mixotrophs. Simulations were performed density linked to cell physiology and growth of ecosystems limited by different light and nutrient condition. Several hypothesis regarding the regimes. Our results show that cell size is an dominate factor controlling the variations in cell important determinant of success for CMs; smaller density have been suggested; with changes in cells dominate in nutrient poor conditions and vacuole density and vacuole size, as well as the larger cells dominate in light-limited environments. macromolecular composition (carbohydrates, The specificity of the prey from which NCMs acquire lipids, proteins and silicate), being the most phototrophy affects their success, with forms able dominate ones. This study presents a model linking to exploit diverse prey dominating under nutrient allometric-scaling and physiological buoyancy limitation. In turn, strict auto- and hetero- trophic control in marine diatoms. This mechanistic trait- competitors increased in relative importance in the based model accounts for variable vacuole transition from nutrient to light limitation, proportion and vacuole density as well as changes consistent with observed biomass ratios. Overall, in macromolecular composition, as a function of we show that mixotrophy has the potential to cell size and growth condition. The results show impact nutrient availability, mass transfer to higher that both, the macromolecular composition and trophic levels and the microbial loop, radically vacuole density play an important role in changing our understanding of plankton food webs. controlling cell density, with shifting dominance Session C: Multifarious lifestyles of marine depending on cell size and growth. These findings microbes are supported by literature values and have not Talk only important implications for the biological understanding of the persistence of diatom cell in Aleksandra Lewandowska the mixed layer, but also unify several hypothesis N. Aberle regarding the dominate driver in diatom buoyancy Does initial diversity influence phytoplankton regulation. In addition to the full model, a simplified response to environmental change? version of the model, suitable for the Numerous studies in different systems have shown implementation in larger ecosystem models, is that local biodiversity and the resistance of presented. ecosystems to environmental perturbations are Poster Session 2 on Tuesday at 17.30. positively linked. Here we argue that this relationship will strongly depend on the initial community assembly and the niche overlap between the local set of species. We performed experiments with natural marine phytoplankton (control and heat stressed) in five different locations to test the effects of changing salinity on ecosystem productivity. More stable communities that were better adapted to the local conditions were more resistant to salinity change. This effect

21 Elena Litchman regions of the Pacific coast: Alaska, California, Katabuchi, Masatoshi; Umemura, Kaito; Koffel Mexico, and Panama. Prey communities developed Thomas; Klausmeier, Christopher under ambient or reduced predation pressure at Traits and immigration determine species each site. We then assessed the effect of predation abundance distributions in experimental on functional divergence (FDiv) of fourteen traits phytoplankton communities and community weighted means (CWM) of all traits Understanding what determines species abundance that define functional space in terms of palatability, distributions (SADs) should provide insights into competition, and survival. To test for differential processes structuring ecological communities. Here effects of predation on native and novel we test a novel theory that combines niche-based interactions, we also built the indices separately for processes with immigration using experimental the native and introduced components of each prey phytoplankton communities. We assembled community. Overall, predation increased functional multispecies communities and grew them at three diversity and shaped functional structure more different temperatures crossed with three different strongly for low latitude prey communities, but levels of immigration. The resulting SAD shapes effects differed among native and non-native depended on level of immigration and species species. Specifically, predation increased FDiv of abundances correlated with how well their introduced species in Panama and native species in optimum temperatures for growth matched the Mexico. Predation also influenced the CWM of treatment temperature. Species with the Topt close introduced species and whole communities from to the experimental temperature had the highest Panama, native species from Mexico, and native abundance, species with the mismatched thermal species from Alaska, with the strongest effect trait were maintained in the community through occurring in the tropics. Key traits that drive these immigration. The study demonstrates that the patterns are being identified and may elucidate niche-based processes and immigration can trait mismatches between introduced prey and produce realistic SADs and that experimental local predators. Therefore, predation had a phytoplankton communities provide an effective stronger influence on the trait distribution of prey way to test new theories of community assembly. communities at lower latitudes where biotic Session E: Biodiversity and ecosystem function interactions are expected to be more intense, but Talk trait responses can also hinge on evolutionary history of co-occurrence. Diana Lopez Poster Session 1 on Monday at 17.30. Amy Freestone Predation pressure increases functional diversity Tom Lorimer and changes functional structure of marine Francesco Pomati, Carlo Albert, Stuart Dennis, communities at low latitudes Marta Reyes, Christian Ebi The intensity of biotic interactions is hypothesized Revealing and exploiting the non-convexity of trait to increase towards the equator. Predation can distributions have a stronger effect on prey composition, Trait distributions in multiple dimensions are biomass and taxonomic diversity in tropical regions used to make inferences about species niches or compared to higher latitudes. Whether predation interactions. These distributions are often assumed shapes patterns of functional diversity and to be convex, but in more than one dimension, the structure of prey communities, however, has not underlying nonlinear processes may break this been explored across a latitudinal gradient. Theory assumption. Moreover, restricting analysis to one suggests consumer pressure increases functional dimension (or treating dimensions as diversity by reducing competitive dominance and independent) can obscure potentially important promoting trait heterogeneity. Therefore, we higher-dimensional differences, thereby increasing hypothesize that predation will increase functional the apparent "noise" in the system behaviour. To diversity and shape functional structure of prey better understand and overcome these potential communities at lower latitudes. In contrast, we problems, we have developed novel graph-based hypothesize that predation will have a weaker measures for trait distribution non-convexity, and effect at higher latitudes. We further hypothesize trait distribution proximity. These measures do not that evolutionary history of co-occurrence can make assumptions about the intrinsic shape biotic interactions, and novel interactions dimensionality or shape of the data. We will among non-coevolved species may lead to stronger present these measures, as well as some results interaction outcomes if prey lack adequate of their application to in situ plankton imaging data defenses to native predators. To test these from a new dual-magnification automatic hypotheses, we conducted a large-scale predator underwater microscope in a lake in Switzerland. exclusion experiment on nearshore sessile marine Poster Session 2 on Tuesday at 17.30. invertebrate communities across 12 sites in four

22 Séverine Martini Consistent with results from vascular plants, the Emile Faure, Floriane Larras, Aurélien Boye, Nicole first axis of ecological variability related mostly to Aberle, Lise Bacouillard, Beatrix Beisner, Lucie resource utilisation, while competitive dominance Bittner, Emmanuel Castella, Michael Danger, Olivier laid separate. Traditional grouping methods poorly Gauthier, Lee Karp-Boss, Fabien Lombard, Frederic captured variation of individual traits or dispersion Maps, Lars Stemmann, Eric Thiebaut, Philippe in multivariate trait space. We argue that Usseglio-Polatera, Meike Vogt, Martin Laviale, macroalgae could eventually be placed along the Sakina-Dorothée Ayata extended primary producer spectrum that already Trait-based approaches: a common framework for encompasses many autotrophic organisms. We freshwater and marine ecologists caution that traditional groups do not efficiently Freshwater and marine ecologists face common capture macroalgal variation, while emergent challenges: to identify the general rules of the classifications or direct use of traits have the functioning of aquatic ecosystems and to develop a potential to better represent physiology and more predictive ecological understanding of them. morphology and hence, to better explain the However, they traditionally form two distinct ecological role of macroalgae. scientific communities with little crossover Poster Session 1 on Monday at 17.30. between them. We argue that a common framework is needed to bridge communication gaps Aurore Maureaud and foster knowledge sharing. This framework K.H. Andersen, L. Zhang, M. Lindegren should transcend local specificities and taxonomy in Food web structure and species interactions reveal order to provide a common ground and shareable mechanisms underlying biodiversity-ecosystem tools to address common scientific challenges. functioning relationships Here, we advocate the use of trait-based The relationship between biodiversity and approaches as a common language for freshwater ecosystem functioning has been extensively studied and marine ecologists. We propose a unification of over the last three decades using experiments, existing definitions and present a synthesis on theoretical models, and more recently traditional as well as recent and promising methods observational data. While most studies focus on for the study of traits in aquatic organisms, species richness effects on ecosystem functioning, including imaging, genomics, and numerical a large degree of variation remain unexplained, modeling. Finally, we highlight challenges and highlighting that other factors besides species perspectives that are common for freshwater and richness are needed to fully understand and predict marine ecosystems and for which trait-based differences and changes in ecosystem functioning. approaches should foster opportunities for future In this study, we use a trait-based food web model research. By bridging the gap between freshwater to investigate the role of food web structure on and marine ecology, as well as between pelagic and multiple ecosystem functions (e.g. biomass, benthic ecosystems, this framework provides a production, productivity, and metabolism). We clear path forward in using traits-based approaches demonstrate that the relationship with species in aquatic ecology. richness depends on the type of ecosystem function Poster Session 2 on Tuesday at 17.30. considered. Furthermore, we show that the level of ecosystem functions is determined by particular Alizée Mauffrey food web configurations, as well as the degree of L. Cappelatti, J.N. Griffin species dominance. Dominance plays a major role Traditional functional groups capture limited in determining the level of biomass in the food web, variation in the trait space of macroalgae occurring via species interactions and occupancy of Macroalgal functional ecology rests on a tradition the trait space. By manipulating the structure of the of classifying species into groups based on gross food web, we show that species using a wider niche morphology or anatomy. However, applications of space (generalist communities) result in more these traditional grouping approaches have yielded connected food webs compared to species with a contradicting results across large sets of species narrow niches (specialist communities), and and spatial scales, as they do not relate to generally reach the same level of functioning with a ecological roles in consistent ways. Here we explore fewer number of species. We show that a trait- the use of multiple, directly measured functional based approach can help understanding ecosystem traits to characterise ecologically-relevant structure and functioning of marine food webs, and variation, i.e., trait space, among macroalgae. We help building research hypothesis for field-based screened 96 British rocky-shore species for 12 studies. qualitative and quantitative traits relating to Poster Session 2 on Tuesday at 17.30. competitive dominance and resource utilisation. We found all traits to be reliable at the species level, i.e., interspecific > intraspecific variability.

23 Donna McCullough Poster Session 2 on Tuesday at 17.30. B. Calfee, E. Zinser, D. Talmy Modeling reactive oxygen species as a possible Holly Moeller control in cyanobacteria community selection Michael G. Neubert, Matthew D. Johnson Reactive oxygen species (ROS) are ubiquitous in the Trait-based evolution of acquired phototrophs: ocean and are detrimental to all cell types. Cells New models for complex endosymbiosis that carry enzymes involved in ROS detoxification Among an organism's most fundamental traits are have costs associated with enzyme maintenance those that govern its metabolic capacity, because and repair, and lower diffusive nutrient uptake due metabolism constrains how species gather to larger cell volume. By considering trade-offs resources through interactions with abiotic and between efficient nutrient acquisition and biotic elements of their environments. Yet maintaining ROS detoxifiers, we plan to use metabolic capacity may also be surprisingly plastic: resource competition theory to assess how nutrient organisms can gain access to novel forms of supply and ROS concentration gradients exert metabolism through interactions with other control on the selection of microbial communities. species. For example, kleptoplastidic (chloroplast- Mathematical models will be developed and stealing) acquired phototrophs retain parameterized with an experimental system photosynthetic machinery from other lineages, allowing competitive and mutualistic interactions transforming their metabolism from heterotrophic among Prochlorococcus (Pro), Synechococcus (Syn), to mixotrophic (combining photosynthesis and and heterotrophic bacteria. Having previously heterotrophy). These lineages represent demonstrated its ability to elucidate the differences hypothetical evolutionary intermediaries along the that cell size and ROS detoxification can make on a endosymbiosis pathway that has allowed numerous community structure, this system is a good fit for eukaryotic lineages to permanently incorporate the empirical testing we have planned. Our models chloroplasts. In this talk, we use a combination of will be used to ask how protection against ROS and empirical and mathematical models to examine the nutrient competition drive large-scale distributions traits that govern this evolutionary pathway. We of Pro, Syn, and heterotrophic bacteria. Our focus on two main classes of traits: those that modeling will provide a quantitative base to govern an organism's ability to retain and replicate understand ROS production and detoxification, and plastids. We use adaptive dynamics to map the the impact of these dynamics on marine primary fitness landscapes that may drive selection for productivity. acquired, and permanent, phototrophy. We then Poster Session 1 on Monday at 17.30. test the model's predictions using a genus of marine ciliates, Mesodinium, whose members span a Mark Miller gradient of reliance on stolen chloroplasts. This Maria Beger empirical model system allows us to identify traits Stability and persistence of reef fish functional that co-vary with photosynthetic capacity, in order groups to identify mechanistic tradeoffs that constrain Distance-based measures of functional diversity are evolutionary capacity. Combining these two sensitive to input parameters and methodology. approaches reveals the environmental and trait The identification of functional groups is space that favors the evolution of different particularly challenging, and is conducted either metabolic strategies. using a-priori knowledge or clustering algorithms. Session C: Multifarious lifestyles of marine Differing communities of species, sets of traits, and microbes clustering algorithms have been used to define fish Talk functional groups, however little attention has been paid to whether similar clusters emerge across studies. Here, we use a detailed and accurate fish trait database, and well-sampled reef communities to identify and compare functional groups emerging from tropical Japan and Australia. We use novel metrics to compare the identity of functional groups in trait space, and determine which species are ‘core’ to each group and which species ‘jump’ between groups. We also evaluate the impact of sampling strategies and trait selection on resultant functional group stability and persistence. We explore our results in the context of reef ecosystem functioning, and present a best-practice approach to identifying fish functional groups.

24 Fanny Monteiro Javier Murillo Jamie Wilson, Joost de Vries, Glen Wheeler Benjamin Weigel, Marieve Bouchard Marmen, Ellen Investigating the effect of size and life cycle on Kenchington coccolithophore ecology and ocean carbon cycling Marine benthic functional diversity on the Flemish in a trait-based global ocean model Cap (Northwest Atlantic) Coccolithophores are a key group of marine The functional diversity of trawl-caught benthic phytoplankton contributing to the global oceanic invertebrate communities was described for the production of calcium carbonate via the production Flemish Cap, a plateau of ~2 km radius in the of coccoliths. While most studies rely on the small northwest Atlantic. Through the use of Hierarchical calcifying Emiliania huxleyi, coccolithophores have Modelling of Species Communities, a statistical a large diversity in size, shape and ecology with framework for analysis of multivariate data, we about 2 species present in the modern ocean and a have identified response-traits to the environment bi-stage life cycle. For instance, within the and evaluated the influence of such traits on the dominant placolith-bearing species (e.g., E. huxleyi, community assembly processes. Although the Calcidiscus leptoporus, Coccolithus pelagicus), cell amount of variation explained by the species’ diameter ranges from 4 to 2 µm and PIC:POC ratio responses to the covariates mediated by the from .2 to 3. Coccolithophores have also 2 main life functional traits was relatively high, the stages, haploid and diploid phases, in which they relationships between particular trait categories change cell size and coccolith properties. This and the covariates were weak and only pointed out highlights the need to include different traits and broad trends. Assemblages from the top of the Bank trade-offs in coccolithophore studies. Here we use (<5 m depth) were characterized in terms of a trait-based model of the global ocean to explore biomass by small- and medium-sized species with the effect of size and life cycle on the distribution, short lifespans, whereas large species with longer diversity and both primary and CaCO3 production lifespans, and broadcast spawners where dominant of the placolith-bearing coccolithophores. The in the deeper assemblages (5 – 15 m depth). Higher model combines the trait-based Darwin ecosystem biomasses of crawlers, scavengers and predator model which accounts for a diverse and adapted species were found in the regularly fished grounds. population of plankton, with the Earth System Assemblages characterized by deep-sea corals and model of intermediate complexity cGENIE, which is sponges showed higher functional diversity and capable of running large ensembles. We present were associated with three discrete functions: here on-going results on how to model size diversity structure forming (and hence biodiversity), nutrient and life cycle of coccolithophores, as well as show cycling, and bioturbation activity. Although current sensitivity experiments on the effect of these key closures to protect Vulnerable Marine Ecosystems traits on coccolithophore ecology and ocean carbon from the adverse impacts of bottom fishing cycling. activities protect most of the functional diversity, Poster Session 2 on Tuesday at 17.30. the spatial scale of influence for each of the functions is unknown and therefore we cannot conclude that the high level of functional diversity found in the current closed areas is sufficient to maintain ecosystem processes over the whole of Flemish Cap. Poster Session 1 on Monday at 17.30.

25 Anita Narwani under future environmental conditions as well as M. Reyes, A.L. Pereira, H. Penson, S.R. Dennis, S. for non-target species. Here we present trait-based Derrer, P. Spaak, B. Matthews models of individuals as tools to explore the Foundation species determine ecosystem biophysical mechanisms underlying genetic properties and stability by changing community connectivity. Our models link life history traits structure and multivariate trait evenness (reproductive timing and location, developmental A major challenge in ecology is to understand rate, migration behaviour, etc.) to the 3D physical determinants of ecosystem functioning and environment to explore how variations in traits stability in the face of disturbance. Foundation change our expectation of modelled connectivity species can strongly shape community structure patterns for zooplankton and fish. Examples from and ecosystem functioning, but their impacts on our lab include explaining connectivity patterns for ecosystem-level responses to disturbance are less coral reef fish communities around Hawai’i Island, well known. Shallow ponds provide a model system and zooplankton species (holoplanktonic copepods) in which to study the effects of such species spanning the Atlantic Ocean. because particular taxa can mitigate transitions Session D: Traits, Networks and Ecosystem between alternate ecosystem states. We Function performed pond experiments to test how two Talk foundation species (a macrophyte and a mussel) affected the biomass of planktonic primary Spiridon Papoulis producers and its stability in response to nutrient Steven Wilhelm, David Talmy, Erik Zinser addition disturbances. In particular, we were Nutrients Explain the Distribution of Restriction interested in determining how taxonomic and Modification Systems in Prokaryotic Genomes multivariate trait variation are affected by The need to understand the principles that control foundation species and mediate ecosystem-level microbial populations is ever increasing as we learn effects. We found that each of the foundation how microbial communities impact the biological species individually reduced phytoplankton processes of the planet. In this study, we focused biomass and tended to increase rates of recovery our efforts in understanding the top-down control from disturbance. When found together, however, of prokaryotic populations by investigating genomic these species reversed these effects, leading to markers indicative of viral predation. Initially, we repeatable phytoplankton blooms, a loss of took a bioinformatics approach to quantify the recovery from large disturbance events, and number of Restriction Modification (RM) systems in increases in temporal autocorrelation of primary prokaryotic genomes as an indirect measurement production. These changes also caused shifts in to infer which organisms are under extreme other ecosystem properties including increases in selection to maintain innate defense systems. RM dissolved oxygen and turbidity and a decrease in systems function by cutting viral DNA to prevent grazer abundances. A structural equations infection, where more RM systems increase the modeling approach showed that blooms of the defense potential of an organism. After the analysis cyanobacterium, Synechococcus, and a resulting of over 13, prokaryotic genomes, we found loss of multivariate trait evenness played key roles Prochlorococcus, a marine picocyanobacterium in driving these changes. Our findings highlight the well-known for its domination of the low-nutrient, important effects that foundation species can have or oligotrophic ocean, consistently had few RM. in governing ecosystem functioning and stability in Contrastingly, we found that the high end of the RM the face of disturbance due to their influence on distribution was dominated by cyanobacteria that community structure and trait variation. generate dense harmful algae algal blooms in Poster Session 1 on Monday at 17.30. eutrophied freshwater systems. Subsequent to our bioinformatic analysis, we undertook an Anna Neuheimer interdisciplinary approach using mathematical J.A.T.K. Wong-Ala, C. Chang, E. Goetze modeling to rationalize how nutrients can drive Trait-based explanations of genetic connectivity selection for the retention and loss of defense patterns for zooplankton and fish. systems in high and low nutrient environments, Connectivity is the rate of exchange of individuals respectively. We found that despite a variety of across populations – a metric thought to be a major viral-host interactions, high nutrients always select controlling factor for a species’ adaptation for an additional defense and that the retention of potential. While connectivity is often estimated RM systems is driven by environmental nutrients genetically, explaining connectivity patterns through viral predation. This suggests microbial requires us to relate observed genetic structure to communities with a higher influx of nutrients will the underlying biophysical mechanisms controlling select for defensive traits relative to communities connectivity. Identifying these mechanisms also with lower available nutrients. allows us to predict population structure patterns Poster Session 2 on Tuesday at 17.30.

26 Andrew Pershing (size, feeding mode), the model is parametrized N.R. Record very simply allowing testing different community Changes in community properties under rapid assemblages and environmental conditions. The warming model is then used to estimate the active carbon The organisms in an ocean community have traits transport mediated by DVM. that allow them to thrive under the prevailing Poster Session 2 on Tuesday at 17.30. conditions at that location. Climate change is now causing rapid shifts in these conditions. We use an Christoph Plum idealized trait-based modeling approach to Philipp Wenta, Dominik Bahlburg, Stefanie Moorthi simulate how marine communities will respond to Interactive effects of resource supply, warming and other climate trends. We initialize our phytoplankton composition and simulations with species that differ in their macrozooplankton grazing on phytoplankton temperature preferences and temperature stoichiometry along the West Antarctic Peninsula tolerances. We impose a trade-off in which Climatological changes along the West Antarctic maximum population growth is higher for Peninsula (WAP) have resulted in shifts in krill and specialists (narrow tolerance) than for generalists salp populations as well as phytoplankton (wider tolerance), but growth rates in the latter composition. Krill and salps represent the most group decline more slowly away from their important macrozooplankton grazers at the WAP preferred temperature. We allow the communities but differ profoundly in feeding biology, population to adjust to a stationary environment (stable mean dynamics, excretion rates and stoichiometric and variance) and then expose them to different demands. Changes in dominance of these grazers rates of warming. We find that rapid warming may have major implications for phytoplankton causes a decrease in the total abundance of composition and (via recycling) resource organisms. Diversity also declines under gradual stoichiometry with subsequent consequences for warming but may increase under extreme warming. the elemental composition of the phytoplankton To test our theoretical predictions, we compared community. Cellular elemental composition of the landings of fish in New England following herbivores and phytoplankton represents an periods of warming, cooling, or little change. We ecophysiological trait that has a strong potential to found a dome-shaped relationship, with maximum modify food web dynamics and biogeochemical landings following periods with little or no trend cycling. However, our knowledge on stoichiometric and reduced landings following both warming and relations in planktonic food webs of remote cooling. ecosystems such as the WAP is limited. The aim of Session B: Food-webs and Trophic Interactions this study is to identify spatial differences in Talk phytoplankton stoichiometry at the WAP ecosystem in relation to grazer abundance, phytoplankton Jérôme Pinti composition as well as cell size distribution. To Thomas Kiørboe, Uffe H. Thygesen, Andre W. Visser assess these relations, we sampled 1 stations Trait-based modelling of multi-trophic diel vertical around Elefant Island and the South Shetland migrations and active carbon transport Islands during a field survey aboard the RV Diel Vertical Migration (DVM) is a key feature of Polarstern in austral summer 218. Spatial pelagic and mesopelagic ecosystems, mainly driven differences in phytoplankton stoichiometry were by predator-prey interactions along a time-varying observed and assigned to resource availability and vertical gradient of light. The migration pattern of spatial patterns of dominant macrograzers. This each organism is intrinsically linked to the patterns study enhances our understanding of the of its conspecifics, its prey and its predators, consequences of climate-change induced shifts in through feedbacks that are hard to understand— plankton community composition on food web but important to consider. DVM is not only dynamics and stoichiometric interactions. important for trophic interactions, but also for the Session B: Food-webs and Trophic Interactions biogeochemistry of the world’s oceans. Organisms Talk preying at the surface and migrating vertically actively bring carbon to depth, accelerating the rate of the biological pump, and directly connecting surface production with the mesopelagic ecosystem. Using game theoretic principles, we present a trait-based mechanistic model to infer the DVM patterns of different classes of pelagic organisms simultaneously, shedding light on the direct effects that different trophic levels can have on each other. Based on key traits each population

27 Friederike Prowe Deepa Rao Bei Su, Markus Schartau Stephanie Dutkiewicz, Michael J. Follows Can mesocosm observations inform model trophic Modeling morphotypes: A trait-based approach to structure? modeling transitions between single cells and Traits controlling plankton trophic interaction colonies of the Phaeocystis genus structure the lower trophic levels of the food web, The Phaeocystis genus is a cosmopolitan with consequences for both higher trophic levels phytoplankton species that has massive, recurrent and the element cycling of carbon, nitrogen and seasonal blooms in high-latitude coastal phosphorus. Observing feeding traits in a complex environments. Although Phaeocystis plays a natural food web is challenging. Controlled fundamental role in carbon and sulphur laboratory conditions facilitate the observation of biogeochemistry, it is often not well represented in traits, but are typically restricted to specific species. marine microbial ecosystem models, partially due A variety of species and the variability of natural to limited observational data. Phaeocystis is a plankton communities can be investigated in haptophyte with a polymorphic life cycle, that mesocosms. Here we investigate whether a model- alternates between free-living, flagellated unicell based analysis of mesocosm observations of food stage (3-8 µm diameter) and a colonial stage webs can inform about the underlying trophic consisting of hundreds to thousands cells living in a pathways. We base our study on the existing model mucus matrix (1s µm - mm in diameter). In its of Larsen et al. (Limnol. Oceanogr. 6, 215, 36-374) colonial stage, Phaeocystis forms near that describes the shift from a diatom- to a monospecific blooms, indicating that it has a bacteria-dominated community by adding a trophic distinct fitness advantage. In essence, Phaeocystis link between ciliates and diatoms. An alternative can be considered as a population with a single model includes a pathway where ciliates and genotype with multiple phenotypes. In this study diatoms are targeted separately by copepods with we explore the trait-trade-offs of multiple passive and active feeding traits. For both model morphotypes. First we use proteomics data to configurations we perform parameter identification develop mechanistic insights into the differences analyses, including maximum likelihood estimation between unicell vs colony stage traits expressed in of the models’ parameter values. We compare the culture treatments based on the KEGG orthology optimised solutions of these models and evaluate database of molecular functions. Second we whether the available observational data suffice to incorporate this Phaeocystis model in a 1D water identify and constrain either of the potential column model to examine competition dynamics trophic pathways. We discuss the explanatory and the seasonal transitions between single vs power of observed changes in community colonial cells. We focus on examining colony- structure, which may guide the development of specific traits that can infer a fitness advantage and trait-based models for large scale biogeochemical observation-based size scaling for the number of applications. cells per colony. These advantages include Poster Session 2 on Tuesday at 17.30. reduction in top down control, changes in how iron is acquired, and increased (size-dependent) internal quota of larger colonial cells. Initial results show that having multiple morphotypes can expand the theoretical and realized niche of model Phaeocystis, potentially enabling it to persist until conditions are favorable. Poster Session 2 on Tuesday at 17.30.

28 Marina Rillo Age structured models allows us to analyze the Mauro Sugawara, Brenno Cabella, Lukas Jonkers, influence of asymmetries in the traits between Michal Kucera, Thomas Ezard different developmental stages on the age On the mismatch in the strength of competition structure and stability of a population. Here we among fossil and modern species of planktonic show how changes in starvation mortality with krill Foraminifera age can lead to large scale population Many clades display the macroevolutionary pattern cycles.Antarctic krill exhibits a five to six year of a negative relationship between diversity and population cycle, with oscillations in biomass diversification rates, and competition among exceeding one order of magnitude.Using data species has been proposed as the main mechanism analysis complemented with modelling of krill underlying this pattern. However, we currently lack ontogeny and population dynamics, we identify empirical insight into how the individual-level intraspecific competition for food as the main effects of ecological interactions scale up to affect driver of the krill cycle, while external species’ diversification. Here we investigate the climatological factors possibly modulate its phase planktonic foraminifera clade that shows the and synchronization over large scales. Our model negative diversity-diversification relationship indicates that the cycle amplitude increases with across the Cenozoic fossil record, and test whether reduction of krill loss rates. Thus, a decline of apex modern communities are regulated by interspecific predators is likely to increase the oscillation competition. We explore two patterns expected amplitude, potentially destabilizing the marine under interspecific competition, under the food web, with drastic consequences for the entire assumption that ecologically similar species Antarctic ecosystem. compete more strongly. (i) Spatial pattern: by Poster Session 2 on Tuesday at 17.30. globally combining species relative abundances in seafloor sediments and a community phylogenetics Fredrik Ryderheim approach, we test for signs of local competitive Thomas Kiørboe, Erik Selander exclusion among ecologically similar species Quantification of trade-offs of toxin production in (defined as closely related or of similar sizes). (ii) PST-producing dinoflagellates Temporal pattern: using sediment-trap time series Studies dedicated to defense mechanisms in spanning from one to 12 years, we analyse whether plankton have often focused on the benefits of the population abundances of co-occurring species co- defense, but have rarely established potential vary negatively through time. The great majority of costs. Dinoflagellates and the toxins they produce our seafloor assemblages show no significant co- are well studied, but so far many experimental occurrence patterns in space regarding phylogeny assessments of the trade-offs have shown defense or size, and are indistinguishable from randomly costs to be insignificant. However, for defense assembled communities. Through time, most mechanisms to be considered adaptive there must species pairs correlated positively, indicating be associated costs; otherwise, non-defended synchronous population dynamics instead of strains would be outcompeted and all species compensatory dynamics. Synchronicity is also would be equally defended, which they are not. In observed between species pairs of similar sizes, addition, toxin production is inducible; i.e., it is closely related or with similar symbiotic strategy. upregulated in the presence of grazers, further Thus, we found no evidence for interspecific suggesting that costs are substantial. The failure of competition structuring extant planktonic experiments to demonstrate the costs may simply foraminifera communities. Neutral processes seem be because experimental assessments are done to dominate how these communities are under resource replete conditions, while costs may assembled, and population dynamics are likely be more significant when resources are deficient. regulated by the abiotic environment and distantly To explore the potential trade-offs, we established related species, rather than intra-clade density chemostat cultures of Alexandrium spp. under dependent processes. To bring community ecology nitrogen-limitation and induced elevated toxin and macroevolution closer together, we need to production using chemical grazer cues. We used consider defining the species pool of direct video-observations to quantify the benefits macroevolutionary dynamics ecologically rather of toxicity, as the fraction of captured cells that are than only phylogenetically. rejected by copepod grazers. We finally quantify Poster Session 1 on Monday at 17.30. the trade-off by exploring the relation between mortality and growth rate of induced vs non- Alex Ryabov induced cells under different regimes of nutrient A. M. de Roos, B. Meyer, S. Kawaguchi, and B. limitation. Blasius Poster Session 2 on Tuesday at 17.30. Competition-induced starvation drives large-scale population cycles in Antarctic krill

29 Angel Segura approximate analytical solutions and dynamic A constraint envelope approach test for competing simulations, in steady and seasonal environments, theories explaining the fluctuations and variability we investigate the patterns and traits that emerge of natural population and communities within the community. We show that, competition Unveiling the mechanisms that molds populations between large protists and juvenile copepods fluctuations is central for understanding the (intraguild predation) defines feeding mode in small dynamic of pest outbreaks, harmful algal blooms or copepods. In productive systems, copepod’s growth extinction risk. We hypothesize that metabolic is strongly regulated by density-dependent restriction to maximum population abundance competition, and therefore productivity increases shapes single population and community at higher mortality rates. Finally, we discuss the fluctuations. Here, we derive a formal theoretical mechanisms that lead to observed seasonal model linking metabolic limits to maximum dynamics for different latitudinal scenarios. This population abundance with the distribution of simple, yet more realistic model, opens the fluctuations of single populations and communities. possibility to improve end-to-end size-structured First, we show that the emergence of fat tails in the models of marine systems and investigate distribution of single population fluctuations is biogeochemical processes such as carbon export caused by the metabolic effect on maximum and trophic transfer. population abundance of periodic changes in Session B: Food-webs and Trophic Interactions resource supply or temperature. Second, we show Talk an explicit link between single population fluctuations and the Laplace distribution of Shlomit Sharoni aggregated community fluctuations. Third, we Itay Halevy derive a general relationship between population The population structure of exponential-growing variance and body mass (called variance-mass phytoplankton is the main determinant of marine allometry; VMA). Predictions were evaluated on an particulate organic matter stoichiometry exceptional data-set of plankton with 15 years of As phytoplankton biosynthesize biomass from weekly samples encompassing ~25 planktonic inorganic substrates, their elemental stoichiometry species from three trophic levels, sampled in the dictates the amount of nutrients transferred to western English Channel (L4 station). This higher trophic levels, and the amount of carbon framework provides a theoretical mechanism to sequestered in the ocean’s interior. Thus, the ratio explain fat-tailed distributions of population of carbon to nitrogen to phosphorus (C:N:P) in fluctuations and the double exponential or Laplace phytoplankton, is a key component of global distribution of community fluctuations observed in biogeochemistry and climate regulation. Recently the L4 data. Finally, it provides a generalization of observed meridional variation in the C:N:P of the VMA model which is able to generate predict particulate organic matter (POM), lacks a robust, patterns of variability among species lifestyles. process-based explanation. On the basis of global Alternative competing models were compared to datasets, local observations and phytoplankton empirical data furthering our understanding about population models, we suggest that the population the determinants of abundance fluctuations. structure of well-adapted phytoplankton is a Poster Session 2 on Tuesday at 17.30. dominant control on POM stoichiometry, and that fine-scale variations in cellular C:N:P, perhaps Camila Serra-Pompei driven by environmental stresses, play a more A.W. Visser, T. Kiørboe, K.H. Andersen minor role. While a change in environmental Emergent patterns in size-structured models of conditions leads to acclimation of some species, copepod communities more importantly, it selects out of the standing Copepods (small aquatic crustaceans) link primary diversity for species suited to the local producers to fish, thus influencing the dynamics of environment, which grow to dominate the both lower and higher trophic levels in marine food- assemblage and the composition of POM. webs and associated biogeochemical cycles. Life Poster Session 2 on Tuesday at 17.30. cycle of organisms strongly influences population dynamics, yet plankton-ecosystem models often omit copepods life cycle. Here we develop a size- and trait-based ecosystem model that includes copepods and their life cycle, protists, detritus, and nutrients dynamics. Using mechanistic individual- level processes, we model population dynamics of key copepod group, characterized by size and feeding mode. Size resolves physiological rates and organisms’ predator-prey interactions. By means of

30 Nuno Simoes Lan Smith a review of mega-fauna symbiotic species Phenotypic plasticity sustains modelled associated with sponges from the Gulf of Mexico phytoplankton size diversity by flattening fitness and the Caribbean Sea gradients, but may confound observed Ecological interactions on coral reefs play a relationships fundamental functioning role and could explain the Inducible phenotypic plasticity has long been high species richness of these habitats. The nature known to impact the growth response of a wide of symbiosis have been recognized as an important variety of organisms, and more recently has been speciation mechanism. Sea sponges are a dominant appreciated as a determinant of biodiversity, element of these environments that contribute to production, and ecosystem function. However, the vertical complexity and texture of the reef considerable uncertainty remains about how intra- matrix, providing a variety of micro-habitats for a specific trait variation may contribute to myriad of reef species. This role is particularly biodiversity. Photo-acclimation is a well known important in the Golf of Mexico and Caribbean sea, example of physiological flexibility for where upon the decline on reef building species and phytoplankton, and a variety of models have been flattening of the reefs due to an increased erosion developed to represent its effects on their growth, rate, sponges help compensate such habitat chlorophyll and nutrient content. I apply a sized- structure reduction, and provide shelter to many structured model accounting for the photo- invertebrate and fish species, significantly acclimation response of phytoplankton (FlexPFT), contributing to the resilience of the region reefs. as well as a control model lacking this response, to The specificity, importance and role of the sponge two contrasting time-series observation sites from symbiotic species interaction is poorly described. A the North Pacific ocean: a relatively calm single sponge can host a single symbiont or more subtropical site (stn. S1) and a more variable than one? Symbionts are so specialized that their subarctic site (stn. K2). As previously reported relationship is exclusive to a single sponge species (Smith et al. J. Plankton Res. 216), compared to the or, can they colonize multiple sponge species? Or, control, the FlexPFT model reproduced better the is the symbiont species an obligate, facultative or available observations of size fractionated general comensalist? This review describes and chlorophyll, nutrients, and primary production and compares all known records of mega-fauna species predicted greater size diversity. Here I clarify that associated with sponges in these two regions. The this is because phenotypic plasticity flattens fitness obtained results quantified the diversity of gradients, quantified here as specific growth rate symbionts associated with each species of sponge, vs. size. This effect contributed more to enhancing determined some patterns that may be molding the size diversity at the more variable subarctic site diversity of associated species, and finally enabled than at the calmer subtropical site. However, at a tentative classification of the symbiont species both sites modelled size diversity differs along the incidental-obligate interactions. The substantially as calculated in terms of chlorophyll, results conclude that the sponge-symbiotic species carbon or nitrogen biomass, because the degree of diversity in the Caribbean Sea is greater than that flexibility differs with cell size, as a result of the of the Gulf of Mexico, although such diversity is size-scaling of traits. Modelled distributions of dominated by alpheid shrimps and amphipods. In chlorophyll over size tend to be substantially less contrast, the taxonomic diversity at the family level even (lower diversity) than those of either fitness is larger at the Gulf of Mexico. or biomass. This suggests that, although much more Poster Session 1 on Monday at 17.30. widely available than observations of biomass or growth rate, chlorophyll-based size distributions should be interpreted with care. Poster Session 1 on Monday at 17.30.

31 Karen Stamieszkin Maren Striebel Using allometry to model copepod-mediated Miriam Gerhard, Apostolos M. Koussoroplis, carbon flux – how well do we estimate key rates? Helmut Hillebrand Ecosystem modeling and trait-based approaches go Phytoplankton community responses to hand-in-hand because efficient computation temperature fluctuations under different nutrient necessitates simplification of natural complexity. concentrations and stoichiometry Ideally, trait-based approaches distill this Nutrient availability and temperature are important complexity to reveal the mechanistic underpinnings drivers of phytoplankton growth and stoichiometry. of an ecosystem, without losing functionality. Size However, the effect of temperature fluctuations on is used as a master trait because it is consistently phytoplankton communities and its interactions linked to metabolic rate, and shows coherent with nutrient supply is unclear. Using a natural patterns along environmental gradients. It also phytoplankton community, we conducted a captures trophic dynamics via idealized laboratory experiment under two temperature predator:prey size ratios. The biological carbon regimes, fluctuating and constant, across 25 pump is an important component of the ocean’s different combinations of N and P supply. In carbon cycle, but it is hard to measure on large comparison with constant conditions, fluctuating enough spatial and long enough temporal scales to temperatures decreased phytoplankton growth see major changes. We developed a size-based rate (rmax) supporting Jensen´s inequality model to estimate carbon flux through different prediction. In addition, the thermal performance export pathways associated with copepods, the curve shape was altered by nutrient conditions. most numerous metazoan in the ocean. These Stoichiometric responses to temperature pathways included organic carbon production as treatments supported the idea that phytoplankton sinking fecal pellets in surface waters, and cellular nutrient allocation can be adjusted respiration of dissolved inorganic carbon at depth according to the temperature regime. However, the during diel vertical migration. We also measured responses shown by the phytoplankton these rates on the 218 NASA EXPORTS field communities to the temperature conditions were campaign to the Subarctic Northeast Pacific Ocean. not highly explained by differences in the species I compare the predicted carbon flux pathways with diversity and composition. Our results suggested measured values, and discuss the efficacy of the that temperature fluctuations interacting with size-based model. I also highlight traits other than nutrient conditions strongly affect the size that could improve model outputs. phytoplankton physiology and stoichiometry at the Poster Session 2 on Tuesday at 17.30. community level. Poster Session 2 on Tuesday at 17.30.

32 Bei Su David Talmy A. Tagliabue Selina Vage Phytoplankton utilisation of dissolved organic Trade-offs modify ecosystem biomass structure phosphorus: Insights from an optimality-based along trophic gradients model In a broad range of terrestrial and aquatic Phosphorus (P) is essential nutrient to life in the environments, predator biomass scales with prey ocean, regulating oceanic primary production in biomass following power laws with exponents less tropical regions and acting as the ultimate limiting than one. Prey production and prey biomass has oceanic nutrient on long timescales. The major also been shown to scale sub-linearly in diverse dissolved inorganic P (DIP) pool in the ocean is systems. We present a general model to interpret phosphate (PO4) and P stress may occur due to widespread patterns of predator-prey and excess nitrogen (N) supply from both anthropogenic production-biomass scaling. The model allows N deposition or N2 fixation, as well as via a decline competition along trophic gradients among prey in absolute physical supply of PO4 in response to with traits governed by a trade-off between enhanced stratification. Under PO4 scarcity, some resource acquisition, and defense against phytoplankton exploit the larger dissolved organic predation. We show that low resource supply phosphorus (DOP) by synthesizing the hydrolytic selects prey that persist at low biomass density but enzyme alkaline phosphatase (AP), which then take up resources rapidly and are subject to intense alleviates P-limitation, but also requires increased top-down control by predators. High resource N investment. It is unclear how the relative trade- supply selects prey that persist at high biomass off between P acquisition and N allocation to P density, but with low affinity for resource acquisition enzymes affects DOP-utilising acquisition, and high ability to resist predators. In phytoplankton in the context of biogeographic the plankton, cell size may be associated with a variations in the availability of N, DIP and DOP trade-off between resource acquisition and defense across the tropical ocean. Here we extend an against predators, and there are clear increases in existing optimality-based chain model of the average cell size along trophic gradients. In fish and phytoplankton cell, to include the physiological terrestrial ecosystems, defensive behaviors may be response of phytoplankton to DOP utilisation, via less tightly linked with organism size, and instead trade-offs associated with AP synthesis. Our model may be driven by allocations of time, energy and represents the observed inverse hyperbolic resources toward predator deterrence and relationship between DIP concentration and AP avoidance. Our theory explains density-dependent activity (APA) via dynamic feedbacks between the variation in behavioral, physiological, and intracellular P demand and ambient DIP availability. morphological traits observed in diverse systems. APA, regulated by the internal P demand, responds Session A: Traits, environments, ecology and rapidly to environmental DIP fluctuation in our evolution model. Via a set of competition experiments with a Talk non AP producing competitor, we find DOP-utilising phytoplankton have an advantage in regions with high DIP-limitation, but only alongside sufficiently high DOP and DIN concentrations. This arises due to the trade-off between P acquisition and N allocation to AP synthesis and is not affected by varying the model assumptions regarding nutrient supplies, N-demand and key physiological traits. Extrapolating our results to the global ocean using NO3, PO4 and DOP datasets permits us to highlight key regions where optimal conditions for APA occurs, which compare well to the patterns that available APA observations inform of. Given the future P scarcity in the tropical ocean in response to enhanced N addition and stratification, DOP- utilisation will become a key trait for understanding the future biogeographical shift of different microbial groups. Further work is needed to include the parallel role for the trace metal co-factors iron and zinc in driving AP synthesis and its spatial distribution. Poster Session 2 on Tuesday at 17.30.

33 Davi Tavares hypothesize that copepod pigmentation is a plastic Jailson Fulgencio de Moura, Esteban Acevedo- trait that will vary with other traits such as size and Trejos, Agostino Merico life style, as well as with the optical environment. Traits shared by marine megafauna and their We present preliminary results from a field study in relationships with ecosystem functions and a 2m deep fjord with varying optical environments. services We quantified both apparent coloration and Trait-based approaches are being promoted for pigment concentrations of individual copepods studying community structure and functions of across a wide range of species and sizes. Both various groups of organisms, including terrestrial apparent coloration and pigmentation plants, phytoplankton, zooplankton, corals, concentrations seemed related to the optical mammals, and microbes. However, we still lack a environment, also when subtracting food pigments. consistent trait-based framework for the study of We discuss our results in light of the consequences marine megafauna, here comprising large fishes of pigmentation for predation risk in different (e.g. billfishes, tuna and sharks), sea turtles, marine optical habitats. mammals (i.e. pinnipeds, sirenians and cetaceans) Poster Session 2 on Tuesday at 17.30. and seabirds. Here we (1) present key traits that are measurable and comparable among marine Ioannis Tsakalakis megafauna, (2) summarise the relationships Stephanie Dutkiewicz, Mick Follows, Joseph Vallino between the identified traits and critical ecological Patterns of phytoplankton diversity driven by functions and services, and (3) discuss the resource fluctuations in a global ocean model relevance of the trait-based approach for marine Resource fluctuations is a main driver of temporal megafauna research and conservation. Although niches among phytoplankton taxonomic or body size has a remarkable impact on the functional groups, affecting species composition organisation of animal communities, attributes and diversity. In this study we focus on the two such as dietary preference, feeding strategy, major periodic processes of resource fluctuations in metabolic rate, and dispersal capacity, have a the ocean, the seasonal and the diel cycle, and strong influence on nutrient transport, trophic- study their importance for understanding large- dynamic regulations of populations, and scale patterns of phytoplankton biogeography and community structure. We show, for example, how diversity. We consider three phytoplankton feeding strategy is correlated to the exposure of functional groups of differing size that represent marine vertebrates to plastics, with potential distinct adaptations to resource fluctuations: small- cascading impacts on population abundances. We size gleaners (high affinity for nutrient uptake), also suggest how a typically overlooked trait like medium-size opportunists (high maximal growth the charismatic potential can be associated with rate) and large-size hoarders (high capacity in critical ecosystem functions like the maintenance of nutrient storage). We will present preliminary biological diversity via the economical revenues results on the biogeography of the three functional generated from tourism. A considerable amount of groups in the global ocean, with a special focus on information on the physiology and ecology of the latitudinal and productivity gradients. Our marine megafauna has been collected by naturalists analysis includes idealized modelling on the effects over centuries and, more recently, by a vast of resource fluctuations and analysis using the MIT network of scientists. This information, we argue, General Circulation Model. In addition, we use a constitutes a solid foundation for the development thermodynamic-based analysis to estimate energy of a trait-based framework for a new wave of flow through phytoplankton community and the studies on marine megafauna. abiotic environment, focusing on the role of trait Session A: Traits, environments, ecology and adaptations to fluctuating resources. evolution Poster Session 1 on Monday at 17.30. Talk

Josefin Titelman Kim Aalborg, Jan Heuschele, Tom Andersen Copepod pigmentation – more colorful and plastic than we acknowledge? While often considered little escape machines with sophisticated behaviors acting at both small and large spatial scales to reduce predation risk, copepods also vary dramatically in pigmentation. Common to all pigmentation patterns, or lack thereof, is that they affect the detectability of an organism to visual predators. We therefore

34 Daniel van Denderen diversity. Environmental dispersal, ecological Ken H Andersen selection and the adaptive generation of new Vertical feeding strategies and pelagic-benthic phenotypes are manipulated within the model, energy flows determine fish food-web structure allowing assessment of their influence on across marine ecosystems community assembly, in terms of both functional Size-based fish community models have been and taxonomic diversity. developed to characterize the structure of fish Poster Session 1 on Monday at 17.30. communities and to describe energy flow between the upper trophic levels in marine ecosystems. Thus Jamie Wilson far, these models have overlooked important TBD aspects of fish diversity that emerge due to TBD variation in feeding straAbsrtegies (e.g. Poster Session 1 on Monday at 17.30. zooplanktivorous, benthivorous) and behaviors (e.g. diel vertical migrations) that are all associated Alexandra Worden with the vertical habitat strategy of a fish. Here, we Session C: Multifarious lifestyles of marine present a size- and trait-based fish community microbes model that resolves the vertical structure of a fish Keynote community from shelf systems to open ocean environments. Fish individuals interact with each Emily Zakem other through predator-prey interactions that are Martin Polz, Mick Follows determined by a combination of habitat overlap in Incorporating metabolic diversity into trait-based the water column and body sizes of predator and modeling frameworks with metabolic functional prey. Our results show how pelagic-benthic energy types flows, in combination with seabed depth, change Microbial activity mediates the global flow of the vertical structure of the fish community and carbon, oxygen, nitrogen, and other elements, determine the dominant fish functional groups. We including climatically significant gases. However, furthermore show that in open ocean regions with non-photosynthetic microbial activity is typically a substantial detritus flux to the seabed (typical for not resolved dynamically or mechanistically in temperate and polar environments), fish feeding global models of the marine and terrestrial interactions may drive a feeding cascade of carbon biospheres, inhibiting predictive capability. to depth. Such cascades do not occur in areas that Understanding the global-scale impact of complex are primarily structured around the pelagic microbial community activity requires a consistent pathway. Our results highlight the driving forces of framework with which to constrain the fish community structure in marine ecosystems. parameterizations of diverse metabolisms. Here, The model can be used as a tool to predict global we describe how the key redox chemistry fish and fisheries production and to examine underlying specific metabolisms can be exploited to climate impacts on upper trophic level marine parameterize diverse metabolic strategies. By ecosystems. quantitatively relating metabolic yields to chemical Session B: Food-webs and Trophic Interactions gradients, the growth and respiration of microbial Talk biomass is systematically related to stoichiometries of substrate consumption, oxidation, and reduction Ben Ward that constitute biogeochemical fluxes. Linked with S. Collins, C.R. Young, B. Sauterey parameterizations of resource acquisition rates, Functional and taxonomic diversity in a global whole organism metabolism can be integrated into ocean metacommunity model trait-based modeling frameworks as metabolic Recent global surveys have unveiled enormous functional types. Benefits of this approach include levels of diversity in marine microbial communities, prognostic metabolic biogeography and ‘gene- with molecular analysis suggesting the existence of fluent’ predictions of community metabolism. The up 15, genera of marine eukaryotes in the photic theoretically grounded, electron-balanced layer of the ocean alone. Analysis of this data framework progresses the description of microbial suggests a division between taxonomic diversity ecosystems towards conservation of energy as well (identified by neutral genetic markers) and as mass. functional diversity (identified by association with Session D: Traits, Networks and Ecosystem genes of known function). We present results from Function am new 'matrix metacommunity model' that allows Talk the emergence of both functional and neutral

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