School of Biological and Marine Sciences Seminar Series 2017/2018

Harmful algal blooms (HABs) – stories from two oceans, future projections and management 

Professor Anna Godhe, Department of Marine Sciences, University of Gothenburg, Sweden 

Dr Andrew Turner, Principal Chemist, Cefas Food Safety Group, Cefas, Weymouth 

Friday 11 May 2018

Phytoplankton form the base of the marine food chain and are responsible for 50% of the CO2 fixation on Earth. However, a few species of algae are harmful in the sense that they produce toxins which sometimes kill marine invertebrates, fishes and mammals. Algal toxins are also known to accumulate in bivalves, and human consumption of such toxic bivalves may be fatal. One prominent group of toxin-producing microalgae are dinoflagellates. We have explored a long-term monitoring series from the eastern Arabian Sea and recorded that during ENSO (El Niño Southern Oscillation) periods the sea surface water temperature increases and the stratification of the water column intensifies. These hydrographic conditions coincide with higher abundances of dinoflagellates. 

During the most recent ENSO event in 2016, the same area was exposed to a large outbreak of ciguatera fish poisoning, which is caused by yet another dinoflagellate toxin which accumulates in fish. Hence, global warming is hypothetically favourable for dinoflagellates at the expense of other phytoplankton groups, and we might have to consider an increase in HABs. We have also further explored the effects of such blooms by looking at the next trophic level and investigated how toxin accumulation in bivalves, and bivalve health will be effected under climate change conditions.

Blue solutions to global challenges: why we need experimental tests of environmental change on species interactions

Dr Nessa O’Connor, Trinity College Dublin

Friday 27 April 2018

The consequences of species loss in the face of environmental change remain difficult to predict, given the complexity of interactions among species and the context-dependence of their functional roles within ecosystems. We have identified the functional roles of several key species in coastal ecosystems and manipulated environmental contexts to test how the impacts of multiple stressors affect rates of ecosystem functioning. The findings of our empirical tests show how predicted increases in wave disturbance and ocean warming, together with climate-driven species range shifts, concurrent with other stressors (e.g. invasive species, nutrient enrichment etc.) are likely to have profound impacts on coastal communities. Our findings underpin the development of a new conceptual model to assess the multiple components of community stability (e.g. resistance, resilience, robustness etc.). Our experimental tests have shown how some of these components may be correlated. If this is correct, it would enable us to more readily make predictions of the effects of stressors on the multiple aspects of community stability. Moreover, we have shown that failing to consider the multidimensionality of stability is limiting our understanding of the factors that regulate ecosystem services and sustainability.

Competition, facilitation and the coexistence of species: lessons from studies in an arid ecosystem

Dr Miguel Franco, School of Biological and Marine Sciences, University of Plymouth

Friday 23 March 2018

Species interactions play an important role in community structuring, but controversy exists over their relative influence and, importantly, over the mechanisms that allow competing species to coexist. The opposite effects of competition and facilitation have been known to operate in arid communities where the limiting factor, water, clearly plays a major role. Forty years ago, a conceptual model of how these two processes allow two interacting plant species competing for this limiting resource to coexist was proposed. However, despite many studies confirming the individual-level effects of competition and facilitation, the integrated effect of these interactions throughout the whole life cycle of the two species had not been documented. We studied the demography of the two interacting plant species on which the conceptual model of replacement (cyclical dynamics) was originally proposed over a seven-year period, and were able to investigate whether this model was correct.

Costs and determinants of weapon use in animal contests

Dr Sarah Lane, University of Plymouth

Friday 9 March 2018

Although fights are often envisaged as violent and bloody encounters, in reality injurious fights are rare. This is because the costs of fighting injuriously usually outweigh the potential benefits. The costs of fighting will vary depending not only upon the individual’s fighting ability and the value of the contested resource, but also on its opponent. Thus,in order to maximise the benefits gained from participating in a contest, individuals must make strategic fighting decisions. One of the most extreme decisions an animal can make during a contest is to inflict an attack on its opponent. While this decision is traditionally seen as advantageous for the attacker and detrimental to the recipient, emerging evidence suggests that the costs of attack are not so straightforward. In this talk, I will discuss the costs of weapon use from a theoretical and empirical perspective and examine the complex interplay between factors which determine whether an individual chooses to strike or flee.

The Deep-Sea Evolutionary Origins of the Vertebrate Brain

Dr Elia Benito-Gutiérrez, University of Cambridge

Friday 23 February 2018

The evolutionary origin of the vertebrate brain is still unclear. It has been a major challenge to trace back homologous brain regions to the simpler brain anatomy of invertebrate chordates. By whole-brain image reconstructions of serially sectioned adult brains, we have found a compelling homologue of the vertebrate telencephalon brain region in amphioxus, a marine invertebrate and, evolutionarily, the most basally branching chordate. This telencephalic region is characterised by a broad FoxG1 domain (possibly induced by a late Hh activation) and molecularly further sub-regionalised into a dorsal domain expressing Emx-Lhx2/9-Pax4/6 and a ventro-medial domain expressing Hh and Nk2.1. The unprecedented finding of Hh in the adult amphioxus brain further suggests that molecules with organising properties might be actively regionalising the amphioxus brain, as in vertebrates, but only late in development and probably after metamorphosis. This is in agreement with our results on neuronal profiling using neurotransmitters and neuropeptides, which clearly show sustained neurogenesis and growth beyond metamorphosis.

The green ‘white ribbon’: how much do we know about the flood and erosion protection provided by shallow intertidal coastal ecosystems?

Dr Iris Moeller, University of Cambridge

Friday 9 February 2018

Wetlands are common features on coasts globally, covering around 756 thousand km2, with medium sea level rise scenarios (50 cm) likely to cause a loss of 46-59% by 2100. While coastal populations are increasingly at risk from flooding and erosion, this is particularly the case on coasts fronted by wetlands. We now know that coastal wetlands provide protection from flooding and erosion through both the effect of their surface characteristics on water flow and their resistant structure. 

This talk will review some of the existing evidence for both aspects, including our true-to-scale experiment in extreme storm surge conditions (such as those experienced in the North Sea in 1953 and in 2013), which showed that NW European salt marsh vegetation reduces non-breaking waves by 14-15% in height over only 40m distance during those extreme conditions. The presence of wetlands thus markedly reduces the overtopping risk of landward sea defences. Further evidence of the geotechnical properties and sedimentary processes of these naturally formed bio-sedimentary features suggests that they act as highly stable platforms, able to respond to sea level rise where sediment delivery is maintained, but potentially most vulnerable to erosion at their seaward margins. Given technological advances in field and remote sensing methods, the capture of information relating to the coastal protection function of vegetated foreshores is now becoming much easier. Possible solutions for incorporating such information into flood and coastal erosion risk management are presented.

Molecular insights into factors controlling phytoplankton evolution and abundance: From nutrient physiology, microbial interactions, to cell signalling 

Dr Katherine Helliwell, The Marine Biological Association, Plymouth

Tuesday 12 December 2017

Marine phytoplankton have vital roles in regulating our global climate, contributing almost half of the biosphere’s net primary production, and representing a critical sink for rising atmospheric CO2. Determining the factors that govern growth of these primary producers, and how they interact, is therefore essential to our understanding of the productivity of aquatic ecosystems. Unlike land plants, many eukaryotic algae require an external source for one or more B vitamins for growth. These water soluble, organic micronutrients play essential roles in central metabolism. Recent progress in algal genetic resources has enabled us to advance understanding of the evolutionary processes and molecular components shaping phytoplankton vitamin dependencies. I will present evidence demonstrating metabolic complexity in the production and bioavailability of different vitamin forms, coupled with specialised phytoplankton acquisition strategies to salvage and remodel vitamin precursors. I will discuss how these findings redefine our view of how B vitamins are cycled in aquatic ecosystems and their importance to structuring phytoplankton communities and microbial interactions.

Potential implications for biotechnology and human nutrition will also be discussed. In the latter half of my talk I will focus on a more recent aspect of my work that applies molecular, genetic and live-cell imaging approaches to decipher signalling mechanisms of marine phytoplankton. This research pays particular attention to the role of Ca2+― the ubiquitous second messenger of eukaryote signalling, in underlying environmental perception processes of a globally important group of eukaryote phytoplankton, the diatoms.

On a wild goose chase for the world's highest flying bird

Dr Lucy Hawkes, University of Exeter

Tuesday 28 November 2017

Many of the most spectacular migrations on earth are made by birds. One notable example is the bar-headed goose, renowned for migratory flights at extremely high altitudes over the world’s tallest mountains, the Himalayas, where partial pressure of oxygen is dramatically reduced while flight costs, in terms of rate of oxygen consumption, are greatly increased. By tracking geese, we show that these birds typically travel through the valleys of the Himalayas, passing over them in less than a day, typically climbing between 4,000 and 6,000 m in 7–8 h. Surprisingly, these birds do not rely on the assistance of upslope tailwinds that usually occur during the day. Bar-headed geese have a suite of adaptations for high altitude throughout the oxygen transport cascade, manifested in an ability of these birds to run at maximum speeds (determined in normoxia) for 15 minutes in severe hypoxia (7% O2; simulating 8500 m altitude) with no decrease in arterial blood oxygen saturation. Barnacle geese (n = 10), on the other hand, were unable to complete similar trials in severe hypoxia. Further, using implanted loggers that recorded heart rate, acceleration, pressure, and temperature, we found no evidence of training for migration in bar-headed geese in advance of migration. It would seem, therefore, that bar-headed geese are capable of sustained climbing flight over the passes of the Himalaya under their own aerobic power.

Fuelling the Future with Synthetic Biology

Professor John Love, The University of Exeter, BioEconomy Centre

Wednesday 1 November 2017

We are witnessing an increasing shift away from reliance on fossil fuels, borne both out of concern for environmental impact, and out of sheer necessity due to the increasing difficulties for exploiting the fossil fuel resources at our disposal. While there is a wide variety of renewable solutions for generation of electricity, most of these fail to address our continued reliance on combustion engines –particularly in modes of transport such as automobiles and aeroplanes. Unless every one of these existing vehicles were to be replaced, at enormous expense, by an electric equivalent, it is clear that the development of some form of commercially available combustible fuel remains essential.The seminar will present the opportunities and difficulties for large-scale, sustainable biofuels production, primarily focusing on the new possibilities offered by the use of synthetic biology to generate the energy-dense, liquid fuels that are required as we transition to a low-carbon economy.

Assessing the potential for pain in crustaceans and other invertebrates

Professor Robert W Elwood, School of Biological Sciences, Queen’s University, Belfast

Tuesday 17 October 2017

All animals face hazards that cause tissue damage and most have nociceptive reflex responses that protect them from such damage. However, some taxa have also evolved the capacity for pain experience, presumably to enhance long-term protection through behaviour modification based on memory of the unpleasant nature of pain. In this talk, I consider various criteria that might help to distinguish nociception from pain. Because nociceptors are so taxonomically widespread, simply demonstrating their presence is not sufficient. Further, investigation of the central nervous system provides limited clues about the potential to experience pain. Physiological changes in response to noxious stimuli or the threat of a noxious stimulus might prove useful but, to date, application to invertebrates is limited. Behaviour of the organism provides the greatest insights. Rapid avoidance learning and prolonged memory indicate central processing rather than mere reflexes and are consistent with the experience of pain. Complex, prolonged grooming or rubbing may demonstrate an awareness of the specific site of stimulus application. Trade-offs with other motivational systems indicate central processing, and an ability to use complex information suggests sufficient cognitive ability for the animal to have a fitness benefit from a pain experience.

Unsuspecting butterflies perish in anthropogenic ecological traps

Professor Michael C. Singer, University of Plymouth

Wednesday 4 October 2017

The late Gary Polis described Homo sapiens as a "ubiquitous keystone pest". From the perspective of most wildlife, it's hard to escape that conclusion. Adaptation to human activities allows some wild species to coexist with us, but many fail to adapt to human land management and suffer in consequence. An example is the setting by humans of ecological traps: "in an environment altered suddenly by human activities, an organism makes maladaptive habitat choices based on formerly reliable environmental cues, despite availability of higher quality habitat" 1. Under this scenario, a novel resource provided by humans is accepted as food, but is at least initially detrimental, with the expectation that evolution should lead either to behavioural avoidance of the resource or physiological ability to use it. By accident, we've documented two examples of a different type of trap in which humans inadvertently provided butterfly populations with novel resources that were not initially preferred, but so WONDERFUL that we effectively invited the insects to evolve preference for them, and then dependence on them. Then we snatched the novel resources away, withdrawing our apparent gift and causing population extinction. This type of event can be completely cryptic to human observers, but from a conservation perspective we may need to understand it, when threatened species are the victims of our tinkering. 

(1 Schlaepfer et al. (2002). Trends Ecol Evol 17, 474)