Surging growth in human populations combined with sweeping industrialisation over recent generations has triggered an unprecedented expansion in our consumption of natural resources. This has led to profound changes in the natural world, with environmental degradation occurring at levels of species’ populations, whole ecosystems, and even the global climate. We have investigated the effects of current marine contamination issues, finding that a common agricultural pesticide disrupts the health and growth of planktonic lobster larvae, and developed a biological test for seawater quality. We have also found that wild recruitment in European lobsters may be affected by climate change, with shell mineralisation and growth both negatively influenced when future scenarios of ocean warming and acidification are replicated in the lab.

Climate Change Effects

2015: Lauren McMillan – Aberystwyth University, BSc project. ‘Using meta-analysis and experimental design to investigate the potential effects of multiple ecological drivers on larval lobsters’
Abstract

It is widely understood that ocean acidification and ocean warming are two of the main dangers facing our oceans in the modern world. Major ecological changes put biodiversity and marine habitats at risk. These stressors have in the past been studied individually and as combined stressors. However increased nutrients or eutrophication has had far less attention given to it as an ecological stressors of the marine environment. Homarus gammarus is an economically and ecologically important species, and is most vulnerable in its larval stage. To understand how this vulnerable life stage would react in a situation of multiple stressors, a preliminary study was conducted, testing temperature and increased nutrients on newly hatched H. gammarus, up to zoea III. The study found that temperature positively affected carapace length, but the interaction of temperature and increased nutrients negatively impacted upon larval biomass. A meta-analysis was also conducted to assess the biological response of larval lobster species to the effects of ocean warming, ocean acidification and eutrophication. The responses of larval lobsters varied depending upon the response measure. The combination of the stressors; increased carbon dioxide (CO2) and increased temperature either exhibited a negative biological response or a response which was not significant. Biomass of larval lobsters showed a synergistic response to combined stressors, however survival, moult duration and carapace length did not. With the frequency with which stressors are likely to interact in the marine environment and the vulnerability of lobster stocks should larval recruitment collapse, it is important to undertake robust studies which account for multiple stressors in varied geographic environments, to make accurate predictions for the future of our oceans health.

2010-2012: Daniel Small – PhD Studentship, Plymouth University. ‘Investigating the synergistic impacts of climate change drivers on the developmental physiology of the European lobster, Homarus gammarus’.
Funded by Plymouth University and the National Marine Aquarium.

Small DP, Calosi P, Boothroyd D, Widdicombe S, Spicer JI. (2016) The sensitivity of the early benthic juvenile stage of the European lobster Homarus gammarus (L.) to elevated pCO2 and temperature. Marine Biology. 163 (3); 1-2.
Full text      Abstract

The early benthic juvenile stage of many marine invertebrates is a key step in the transition from the planktonic larval stages to the benthic adult stage. It is characterised by high mortality, in part, due to sensitivities to abiotic factors. The impacts of elevated pCO2 and temperature on the physiology and life history of these sensitive life stages are, however, poorly understood. Consequently, the aim of the present study was to investigate the vulnerability of survival, growth, metabolic rate, feeding rate, organic content, and carapace mineralisation of the early benthic juvenile stage of the European lobster Homarus gammarus (L.) to predicted levels of elevated pCO2 [ocean acidification (OA) and carbon capture and storage (CCS) scenarios] and elevated temperature [ocean warming (OW)]. Early benthic juvenile H. gammarus exhibited increased mortality under both OA and CCS conditions at both experimental temperatures, and these mortalities were due to moult death syndrome. There were OA-related reductions in metabolism, food acquisition, and carapace mineral content, while CCS-exposed lobsters exhibited severe shell dissolution. We suggest that disruption of metabolic and calcium homoeostasis is associated with, and possible the cause of, the increased incidence of moult-related mortalities in juvenile lobsters. We conclude that early benthic juvenile lobsters are sensitive, in terms of physiology and life history traits, to both OA and CCS, with OW sometimes mitigating and at other times increasing sensitivities.

Small DP, Calosi P, Boothroyd D, Widdicombe S, Spicer JI. (2015) Stage-specific changes in physiological and life-history responses to elevated temperature and pCO2 during the larval development of the European lobster, Homarus gammarus (L.). Physiological and Biochemical Zoology. 88(5); 494-507.
Full text      Abstract

An organism’s physiological processes form the link between its life-history traits and the prevailing environmental conditions, especially in species with complex life cycles. Understanding how these processes respond to changing environmental conditions, thereby affecting organismal development, is critical if we are to predict the biological implications of current and future global climate change. However, much of our knowledge is derived from adults or single developmental stages. Consequently, we investigated the metabolic rate, organic content, carapace mineralization, growth, and survival across each larval stage of the European lobster Homarus gammarus, reared under current and predicted future ocean warming and acidification scenarios. Larvae exhibited stage-specific changes in the temperature sensitivity of their metabolic rate. Elevated PCO2 increased C∶N ratios and interacted with elevated temperature to affect carapace mineralization. These changes were linked to concomitant changes in survivorship and growth, from which it was concluded that bottlenecks were evident during H. gammarus larval development in stages I and IV, the transition phases between the embryonic and pelagic larval stages and between the larval and megalopa stages, respectively. We therefore suggest that natural changes in optimum temperature during ontogeny will be key to larvae survival in a future warmer ocean. The interactions of these natural changes with elevated temperature and PCO2 significantly alter physiological condition and body size of the last larval stage before the transition from a planktonic to a benthic life style. Thus, living and growing in warm, hypercapnic waters could compromise larval lobster growth, development, and recruitment.

2007-2008: Katie Arnold – Independent research funded by the European Social Fund. ‘Effects of Ocean Acidification on Larval Lobsters’.
Research collaboration with Plymouth University, University of Exeter, and the Plymouth Marine Laboratories.

Arnold KE, Findlay HS, Spicer JI, Daniels CL, Boothroyd D. (2009) Effect of CO2-related acidification on aspects of the larval development of the European lobster, Homarus gammarus (L.). Biogeosciences. 6 (8); 1747-1754.
Full text      Abstract

Oceanic uptake of anthropogenic CO2 results in a reduction in pH termed “Ocean Acidification” (OA). Comparatively little attention has been given to the effect of OA on the early life history stages of marine animals. Consequently, we investigated the effect of culture in CO2-acidified sea water (approx. 1200 ppm, i.e. average values predicted using IPCC 2007 A1F1 emissions scenarios for year 2100) on early larval stages of an economically important crustacean, the European lobster Homarus gammarus. Culture in CO2-acidified sea water did not significantly affect carapace length of H. gammarus. However, there was a reduction in carapace mass during the final stage of larval development in CO2-acidified sea water. This co-occurred with a reduction in exoskeletal mineral (calcium and magnesium) content of the carapace. As the control and high CO2 treatments were not undersaturated with respect to any of the calcium carbonate polymorphs measured, the physiological alterations we record are most likely the result of acidosis or hypercapnia interfering with normal homeostatic function, and not a direct impact on the carbonate supply-side of calcification per se. Thus despite there being no observed effect on survival, carapace length, or zoeal progression, OA related (indirect) disruption of calcification and carapace mass might still adversely affect the competitive fitness and recruitment success of larval lobsters with serious consequences for population dynamics and marine ecosystem function.

Environmental Pollutants

2014-2015: Maite Ruiz – Independent research funded by the Coastal Communities Fund, Waterloo Foundation, and the European Centre for Human Health’s In Residence scheme. “Developing bioassays to assess water quality for lobster larval culture.”
Research collaboration with the European Centre for Human Health.

Daniels C, Ruiz-Perez M, Franks S, Schmidt W, Redshaw CH. Development and validation of a bioassay for assessing acute impacts on European Lobster (Homarus gammarus) larvae. (Manuscript in preparation.)
Abstract

The heavy reliance of agriculture on pesticides, to assure quality and maximal productivity can result in downstream pollution of aquatic environments. The subsequent effects on non-target organisms are established for certain species, but remain largely unknown. This pollution can be problematic for aquaculture, which relies heavily on the use of natural water sources. The present study sought to develop a species specific biological assay that could be used to determine the suitability of water sources for use in aquaculture. The bioassay developed herein represents a simple low-cost technique that could be used to evaluate potential toxicity of any water-borne compound on H. gammarus. Additionally, this bioassay also has direct practical applications for assessing the suitability of water sources for rearing H. gammarus under culture conditions.

2007: Katie Arnold – Plymouth University, MSc thesis. ‘Effect of an insect juvenile hormone analogue, Fenoxycarb®, on development and oxygen uptake by larval lobsters Homarus gammarus’.

Arnold KE, Wells C, Spicer JI. (2009) Effect of an insect juvenile hormone analogue, Fenoxycarb®, on development and oxygen uptake by larval lobsters Homarus gammarus (L.). Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology. 149 (3); 393-396.
Full text      Abstract

Little attention has been focused on the effect of anthropogenic compounds that disrupt the endocrine systems in crustaceans. Consequently, this study investigated the effects of the juvenile hormone analogue (JHA), Fenoxycarb® on selected physiological and developmental processes of the zoeal stages in the European lobster, Homarus gammarus. Chronic exposure to Fenoxycarb (50μg L− 1) resulted in a significant (p b 0.05) reduction in moult frequency and size at moult. Fenoxycarb exposure extended zoeal duration between zoea I to II (pb0.05) and resulted in total inhibition of the moult from zoea II to III. Significantly greater rates of O2 uptake were observed in Fenoxycarb-exposed larvae in comparison with controls (pb0.05). All rates of O2 uptake decreased significantly between 7 and 12d of exposure (pb0.05). At 12d, exposure to the solvent control no longer influenced rates of O2 uptake, but it was not possible to attribute increased O2 uptake to Fenoxycarb exposure directly, as treated individuals did not moult beyond zoea III. The low exposure concentrations of Fenoxycarb, comparable to those used in plant protection, resulted in endocrine disrupted responses in H. gammarus (albeit with little clear, demonstrable effect on metabolism) a finding that could have important ecological and commercial implications.

 

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