The Darwin Plus project focusing on climate resilience in the Falkland Islands marine ecosystem and fisheries has hit the ground running with lots of different things happening. We trialed our methods for observing zooplankton in Berkeley Sound under the supervision of Peale’s dolphins, sea lions and penguins, and who could ask for better supervisors? We have received our new bongo net, which will allow us to sample zooplankton at two different size classes. It was great using it for our first spring zooplankton samples, and we will continue to use them to capture the rate of change of the zooplankton community and investigate the diversity, abundance, and biomass of various species in the nearshore marine environment. These data will inform our future ecosystem model regarding the seasonal change in zooplankton as well as provide data for a new PhD student who will investigate inshore-offshore connections, life history and genetics in these species.
Further, we have made a lot of progress on the physiology part of the project. Part of understanding how climate change may affect the ecosystem is understanding how animals respond to warming. This can be studied in individual species via the use of controlled experiments where we can determine how well animals do at ambient temperatures and under different warming scenarios. This work would not have been possible without the help of two project partners: British Antarctic Survey (BAS) in the UK and Fortuna via FIFCA here on the Falkland Islands. Dr Simon Morley from BAS has been over to our beautiful Islands to help set up and provide training for the physiological experiments. Without the aquacultural facilities of Fortuna, we would not have been able to set up and conduct these experiments so we are immensely grateful to Fortuna for providing the space and materials for our investigations
There are several key species in the marine environment of the Falkland Islands, including squid (e.g., Doryteuthis gahi), rock cod (especially Patagonotothen ramsayi), lobster krill (Munida) and an amphipod (Themisto gaudichaudii) that are all important in the food web and the first two are also important commercially. Further, inshore kelp forests play an important role as nurseries for many species, such as for squid and rock cod. We will investigate the animals (as well as kelp later in the year) to determine whether they are “winners” or “losers” under climatic warming conditions. We can determine this by estimating their respiration rate. Many of our marine fauna are ectotherms, so they cannot generate their own body heat (humans and other mammals can; we are endotherms). Ectotherm body temperatures are thus equal to the environmental temperature. Respiration rate is a measure how organisms are doing, and specifically how quickly there are using energy. Quicker respiration rates are an indication that more energy is used up, and thus also that more energy (food) intake is required. However, all animals have an upper thermal limit above which they cannot survive. The respiration rate can indicate things are not going well as there will be a quick drop in the respiration rate. By understanding this relationship between temperature and respiration rate, we can understand how organisms may respond to climate change. This temperature-respiration relationship varies between species, geographical locations, and life stages. Our physiological experiments will estimate respiration rates of various organisms in response to warming, and these relationships we will obtain will be used in our future ecosystem model to help understand how organismal responses to climate change may affect directly and indirectly (via changes in prey-predator food-web connections) the marine ecosystem. While we are still far away from that model, it is exciting to start obtaining the relationships that will inform the model via the experiments we are currently working on.