Marine larval and benthic ecology
Luis Gimenez, School of Ocean Sciences Bangor University. Email: l.gimenez@bangor. ac.uk
Welcome: We study the ecology of marine benthic invertebrates
Research topics:
Multiple stressors - Marine heatwaves - Hypoxia - Range expansions
Publication List
Latest publications
Marine heatwaves impact organism developmental time
Giménez L, Torres G
Communications Earth and Environment
Understanding the effect of marine heatwaves on organisms is central for improving climate change predictions. Even moderate heatwave events are likely to drive performance of organisms especially if they are long relative to the life cycle duration. In ectotherms, such events will affect biological time on a stage-dependent basis; they could alter the timing of life cycle events (e.g. spawning, reproduction) and cause reproductive failure. We use a mathematical framework to explore three different scenarios for the causal relationship between temperature and developmental time and help future experimental research. Here, we highlight the need to experimentally test for (1) stage-dependent responses to temperature and (2) plastic responses to the thermal history. (3) Consider traits linked to developmental time (e.g. body size) and (4) integrate across levels of organization to develop stronger explanatory models. Experiments need to manipulate the timing, duration, and magnitude of warm events.
Heatwave duration, intensity and timing as drivers of performance in larvae of a marine invertebrate
Deschamps MM, L Giménez,C. Astley, M Boersma, G Torres
Scientific Reports
In marine ecosystems, crustaceans face an alarming threat from the increasing frequency and intensity of marine heatwaves as their early planktonic stages are particularly temperature sensitive. While the impact of heatwaves on adult crustaceans is well-studied, their effects on larvae remain underexplored. This study focuses on heatwave effects on larvae of the European shore crab, Carcinus maenas. Through a factorial experiment, larvae were exposed to different heatwaves of varying onset timings, durations, and intensities. Survival, development duration, and dry mass decreased under intense heatwaves, with more severe effects observed when heatwaves occurred later in development, highlighting a stage-specific sensitivity to heatwave. We also identified a “region of existence” beyond which larval performance was compromised compared to baseline temperatures. This region defines the heatwave components considered “extreme” for the organism, as well as those inducing neutral or positive effects on performance. Additionally, we distinguished heatwave effects (characterised by their components) from those attributed to the average temperature experienced during the experiments. Our findings demonstrated that larval performance was lower during intense heatwaves compared to the performance expected under a constant average temperature. These findings emphasize the importance of considering heatwave timing relative to the life cycle for predicting marine population responses to climate change.
Larval physiological responses to temperature across the European distribution range of a global invader at home: the shore crab Carcinus maenas
Geißel JP, Espinosa-Novo N, Giménez L, Aberle N, van der Meeren GI, Harzsch S, Boersma M, Torres G
Ecology and Evolution
In marine species with complex life cycles, thermal tolerance is usually narrower in larvae than in adults. Hence, range contraction and expansion, as a consequence of climate change, may be enhanced or hampered by among-population variability in the thermal tolerance of larval stages. We quantified the performance (i.e., survival, development, and growth) of larvae of the shore crab Carcinus maenas at different temperatures (range 9°C to 27°C in steps of 3°C) in populations located towards the limits of the European distribution range (South: Vigo, Spain; North: Bergen and Trondheim, Norway). We hypothesised that, given the geographical distance, larvae from northern populations would show increased tolerance to low temperatures while those from southern populations would show increased tolerance to high temperatures. Such patterns would enhance poleward range expansion and counteract contraction as compared with a scenario where thermal tolerance does not change along the latitudinal gradient. Populations from southern Europe (Spain) showed slightly increased survival at higher temperatures compared to those further north and in invasive North American populations. However, there was little variation in larval tolerance between populations of Northern Spain and Norway: survival and growth rates were low at temperatures 9°C and 27°C. Larvae from the northernmost European populations (Norway) showed significantly shorter duration of development at low temperatures, which might have an adaptive value, contingent on the actual pattern of temperatures experienced during the larval phase. Further range expansions (or contractions) are likely to be driven solely by increasing temperatures unless populations located right at the range limit show increased tolerance to low (or high) temperatures.
Plankton communities today and tomorrow—potential impacts of multiple global change drivers and marine heatwaves
Meunier CL, Schmidt J, Ahme A, Balkoni A, Berg K, Blum L, Boersma M, Brüwer JD, Fuchs BM, Gimenez L, Guignard M, Schulte-Hillen R, Krock , Rick J, Stibor H, Stockenreiter M, Tulatz S, Weber F, Wichels A, Wiltshire KH, Wohlrab S, Kirstein IV (2025)
Limnology and Oceanography
In the context of global change, marine organisms are subjected not only to gradual changes in abiotic parameters, but also to an increasing number of extreme events, such as heatwaves. However, we still know little about the influence of heatwaves on the structure of marine communities, and experimental studies are needed to test the impact of heatwaves alone and in combination with other environmental drivers. Here, we conducted a mesocosm experiment to assess the potential impact of heatwaves on plankton communities, which we did under ambient and future environmental conditions. To simulate future environmental conditions, we simultaneously manipulated temperature and pH based on IPCC predictions for 2100, and dissolved N : P ratios based on the conditions expected in European coastal zones. While we did not observe any effects of simulated heatwaves on phytoplankton abundances, we identified that future environmental conditions may favor smaller phytoplankton species and that additional heatwaves may especially favor small phytoflagellates and coccolithophores. We also observed that future environmental conditions may reduce the abundances and modify the species composition of bacterioplankton, microzooplankton, and mesozooplankton, and that heatwaves may exacerbate these effects. Using a unique approach to examine the potential impacts of heatwaves under current and future environmental conditions on a natural multi-trophic marine plankton community, we show that the combination of multiple global change drivers has the potential to perturb the entire basis of marine food webs.
A Trends in Early Larval Traits of a Global Invader at Home Across a Latitudinal Gradient: The European Shore Crab Carcinus maenas
Geißel JP, Espinosa-Novo N, Giménez L, Aberle N, van der Meeren GI, Rautenberger R, Harzsch S, Torres
Journal of Biogeography
Aim: This study sets out to understand the variability in larval traits of dispersive life stages of a famous invader, the European shore crab Carcinus maenas, in its native distribution range. Location: North East Atlantic coast from the Norwegian Arctic to the southern European distribution limit of C. maenas in Southern Spain. Taxon: European shore crab Carcinus maenas (Crustacea, Decapoda). Methods: We quantified latitudinal patterns in larval body mass, elemental composition (C and N content), and thermal tolerance of the first larval stage. We collected crabs from four populations spanning 25° of latitude (Vigo in Northern Spain; Bergen, Trondheim, and Bodø in Norway) and reanalysed published and unpublished data of body mass and elemental composition of additional populations from Germany, Wales, France, and Southern Spain. Furthermore, we used two laboratory experiments to test the thermal tolerance limits of the first larval stage from Vigo and the Norwegian populations. In the first experiment, we reared larvae from hatching to Zoea II at seven temperatures (9°C–27°C) and from hatching to LT50 at 6°C. In the second experiment, we exposed freshly hatched larvae acutely to increasing or decreasing temperatures (up to 40°C and down to 3°C). Results: Across the entire European range, we found a substantial increase in dry mass and carbon and nitrogen content of freshly hatched larvae with latitude. Norwegian populations exhibited higher survival at 9°C than the Vigo population. Furthermore, LT50 at 6°C increased from South to North. All populations showed high survival in the range 12°C–24°C but low survival at 27°C. Main Conclusions: Larval tolerance quantified by using survival to Zoea II is not clearly related to the tolerance quantified with the acute experiments, indicating that each method assesses different aspects of thermal tolerance. Tolerance to low temperature correlated positively to tolerance to high temperature, suggesting that variation among females in larval responses reflects a general physiological quality rather than trade-offs. We provide evidence for potentially adaptive variations in larval body mass and thermal tolerance across a latitudinal gradient for C. maenas.
A geometric approach to understanding biological responses to environmental fluctuations from the perspective of marine organisms
L. Giménez
Marine Ecology Progress Series
A main concern in marine ecology is understanding the mechanisms driving the responses of biological systems to environmental fluctuations. A major issue is that each biological system (e.g. organism, ecosystem) experiences fluctuations according to its own intrinsic characteristics. For instance, how an organism experiences a thermal fluctuation, i.e. as a long marine heatwave or as a mild pulse, depends on its thermal tolerance and developmental time, which can vary as the fluctuation is experienced. Here, a geometric approach is explored, considering the biological perspective. Environmental fluctuations are represented as points in a ‘space of fluctuations’. The biological perspective is then defined as a coordinate frame within that space. Coordinates are given by components (e.g. amplitude and time scale) characterising each environmental fluctuation, which are then transformed into biological scales, using biological traits (tolerance and biological time). Using simulations of organisms growing under thermal fluctuations with different characteristics, the present study shows how this approach (1) enables the integration of physiology and phenology to better interpret biological responses to fluctuating environments; (2) improves our understanding of the role of adaptive plasticity as a rescue effect; and (3) facilitates our understanding of the effects of thermal fluctuations on additional organismal traits (e.g. body mass). Wider applications in the context of species persistence, coexistence, biodiversity and ecosystem function in scenarios of extreme fluctuations are also discussed.
On their way to the north: larval performance of Hemigrapsus sanguineus invasive to the European coast—a comparison with the native European population of Carcinus maenas
Espinosa-Novo N, Giménez L, Boersma M, Torres G
The Asian shore crab Hemigrapsus sanguineus has become invasive in North Europe and it co-occurs and competes with the native European shore crab Carcinus maenas. Both species develop through a feeding and dispersive larval phase characterised by several zoeal and a settling megalopa stage. Larvae of marine crabs are vulnerable to food limitation and warming has the potential to exacerbate the negative effects of food limitation on survival and growth. We quantified the combined effects of temperature and food limitation on larval performance (survival and growth) of H. sanguineus and we compared our results with those reported on performance of C. maenas larvae, under the same experimental design and methodology. Larvae from four females of H. sanguineus collected on Helgoland (North Sea) were experimentally reared from hatching to megalopa, at four temperatures (range 15–24 °C) and two food conditions (permanent vs. daily limited access to food). Larval survival of H. sanguineus was low at 15 °C and increased with temperature, in contrast to the high survival reported for C. maenas larvae in the range 15–24 °C. Food limitation reduced survival and body mass of H. sanguineus larvae at all temperatures, but without evidence of the exacerbating effect caused by high temperatures and reported for C. maenas. By contrast, high temperature (24 °C) mitigated the negative effect of food limitation on body mass on H. sanguineus larvae. Advantages of H. sanguineus over C. maenas appear especially under the increased temperatures expected from climate change.
Investigation of marine temperature changes across temporal and spatial Gradients: Providing a fundament for studies on the effects of warming on marine ecosystem function and biodiversity
de Amorim F, Wiltshire K, Lemke P, Carstens K, Peters S, Rick J, Giménez L, Scharfe M
A current critical issue in climate change studies is how temperature changes and shifts on different spatial and temporal scales can affect organisms in terms of trends, variability and frequency of extremes. In this paper, we analysed marine temperature data on different temporal and spatial scales. We related the sea surface temperature data from the Helgoland Roads Time Series, one of the most important and detailed long-term in situ marine ecological time series, to the Sylt Roads, North Sea, Germany, Europe, North Atlantic and Northern Hemisphere surface temperatures. All time series showed a distinct upwards shift in temperature in the late 1980s, early 1990s, with positive trends in overall for the period between 1962 and 2019 ranging from 1 to 2 °C over 57 years. We quantified changes in temperature variability by comparing the years before and after 1990, on both long-term and seasonal scales. At Helgoland and Sylt, an increase in the number of warmer days in summer and a decrease in extremely cold days in winter are the new characteristics of the temperature pattern after 1990; higher than expected temperatures now also occur earlier during the year. For these locations, we observed the highest trends overall, i.e. of around 0.3 °C/decade. The observed bimodal shape of the probability density functions, characterized by winter and summer modes, had become more heterogeneous, with the cold mode peak moving to higher values and the steepness to the peak increasing, which is a consequence of a decrease in extremely cold days. North Atlantic Oscillation (NAO) and Multidecadal Oscillation (AMO) large-scale phenomena had no significant correlations or, for the NAO, were limited to the winter season at the regional and local scales. The closest landmass (mainland Germany) temperature was highly correlated with the North Sea sites. Taken together, our results suggest that marine pelagic ecosystems and their species are subject to temperature shifts with similar patterns but with variations in magnitude at the different scales. Temperature is one of the main drivers of species diversity and distribution, and this manifests on different spatial and temporal scales depending on population growth, life stages, cycles and habitat. Accordingly, we here present the temperature changes on the appropriate spatio-temporal scales, and thus provide the suitable and useful fundament for studies on the effects of warming on marine ecosystem function and biodiversity.
Thermal acclimation and habitat-dependent differences in temperature robustness of a crustacean motor circuit
Stein W, Torres G, Giménez L, Espinosa-Novo N, Geißel JP, Vidal-Gadea A, Harsch S
Frontiers in Cellular Neuroscience
Introduction: At the cellular level, acute temperature changes alter ionic conductances, ion channel kinetics, and the activity of entire neuronal circuits. This can result in severe consequences for neural function, animal behavior and survival. In poikilothermic animals, and particularly in aquatic species whose core temperature equals the surrounding water temperature, neurons experience rather rapid and wide-ranging temperature fluctuations. Recent work on pattern generating neural circuits in the crustacean stomatogastric nervous system have demonstrated that neuronal circuits can exhibit an intrinsic robustness to temperature fluctuations. However, considering the increased warming of the oceans and recurring heatwaves due to climate change, the question arises whether this intrinsic robustness can acclimate to changing environmental conditions, and whether it differs between species and ocean habitats. Methods: We address these questions using the pyloric pattern generating circuits in the stomatogastric nervous system of two crab species, Hemigrapsus sanguineus and Carcinus maenas that have seen a worldwide expansion in recent decades. Results and discussion: Consistent with their history as invasive species, we find that pyloric activity showed a broad temperature robustness (>30°C). Moreover, the temperature-robust range was dependent on habitat temperature in both species. Warm-acclimating animals shifted the critical temperature at which circuit activity breaks down to higher temperatures. This came at the cost of robustness against cold stimuli in H. sanguineus, but not in C. maenas. Comparing the temperature responses of C. maenas from a cold latitude (the North Sea) to those from a warm latitude (Spain) demonstrated that similar shifts in robustness occurred in natural environments. Our results thus demonstrate that neuronal temperature robustness correlates with, and responds to, environmental temperature conditions, potentially preparing animals for changing ecological conditions and shifting habitats.