Jenny Day & Freshwater Ecology

How I became a freshwater ecologist

Like many students of my generation, I wanted to do medicine. I suppose I had a romantic notion of striding down long corridors in a white coat with a stethescope hanging out of my pocket. In reality, however, I didn’t get a very good Matric and so I wasn’t accepted into first-year medicine. Like most of us in that position, I thought that if I did well enough in the first year of a BSc, I would then be accepted into medical school. That was true, but reality came to the fore once again: I really wasn’t a very good student and Medicine scorned my application once again. Nothing daunted, I continued with the three-year BSc degree, again intending to apply to Medicine when I graduated. But something strange happened: I fell in love with science, and with invertebrate animals in particular. This was driven at least in part by the marine field trip we did to Langebaan in the Easter vac of our second year. What a mind-blowing experience! We dug in mud - and found worms; we searched the rocky shore - and found barnacles and crabs and snails and an immense array of tinier and completely unknown beasties, unknown to me at least. Back in the lab we dissected some of them, and found out how beautifully and cleverly they are constructed. To this day I would rather spend an hour marvelling at the tiny lives revealed by a microscope than spend an hour watching lions stalking their prey. I really would.

My new interests reawakened my academic abilities, which had been cowed by my obvious lack of progress at university. I did really well in third year, even though in Zoology it mostly covered vertebrates, including a lot of emphasis on bones from fish to mammals, and highly hypothetical analyses of potential evolutionary pathways. I also took a second year of Chemistry, which has stood me in much greater stead throughout my career. In Honours we had to do four (yes - FOUR) projects. One of mine was on the distribution of Cumacea (small shrimp-like benthic crustaceans) in False Bay, one was on the feeding mechanism of a local intertidal gastropod, Argobuccinum argus (now with the ghastly name Argobuccinum pustulosum) and a third on its production of sulphuric acid as a means of boring into the shells of its bivalve prey. The fourth was a biochemical study of the enzyme LDH (lactic acid dehydrogenase) in invertebrates. I mention all of these because they were all important for my future studies. As a result of my work on Argobuccinum I was invited to attend a symposium of the AAAS (the American Society for the Advancement of Science) in Dallas, Texas, where I presented my first conference paper (a truly scary experience for a young South African student abroad!) and which resulted in my first published paper. The LDH work led to me beginning an MSc on that enzyme. I later realised that the subject was far too sophisticated for the equipment and expertise we had in the Department (indeed in South Africa) at the time; I was greatly relieved when my supervisor resigned in order to emigrate to the USA and I also found out that I was pregnant (the two being entirely unrelated!), giving me two excellent excuses to abandon that impossible project. It also saved the lives of many octopuses, which were my study animal, and which I greatly admire.

You will note that hardly a word has been said about ecology, let alone wetlands, and I suppose it’s true to say that I fell into both serendipitously. At about that time I became a Junior Lecturer in the Zoology Dept at UCT, and by now I also had two small children, yet I decided to start a PhD project too. (I can’t for the life of me remember why I thought that that was a good idea at the time: I think “sucker for punishment” more or less covers it.) I needed a thesis topic that could co-exist with my duties as wife and mother and lecturer, and bethought me of the beautiful little critters of my Honours project: Cumacaea. So I landed up doing a PhD on the taxonomy of several families of South African Cumacea. I loved those tiny beasties (hardly any of them more than a centimeter long), but the excitement of drawing and describing species after species soon began pall. I eventually competed the thesis and looked about for something new to get my teeth into. And something serendipitous happened, once more.

A colleague and friend, Jenny Jarvis, worked on naked mole rats in Namibia. There was unexpected rainfall during one of her field trips to the middle of the Namib Desert and Jenny noticed a pond by the side of the road. It was just a couple of meters across, and maybe 20cm deep at most. But zooming around in it were remarkable little crustaceans that, had they been magnified a hundred times, would have convinced her that she was in Jurassic Park. There were shield shrimps looking like animated trilobites, fairy shrimps with gossamer gills and golden gonads swimming upside down beneath the surface film, clam shrimps in coitus, males holding females at 90 degrees in front of them and using them as battering rams, to say nothing of even smaller ostracods and copepods, their tiny movements adding a shimmer to the water. Jenny was entranced, but more important she thought of my interest in crustaceans. So she collected a whole lot of individuals, which now became inanimate specimens. On her way past the area on her return home, however, she noticed that the pond had entirely disappeared, and that the soft bottom sediments held some tiny corpses. To her eternal credit, and to my delight, she collected some of that dry sediment. When she returned o UCT, she gave me one of the best and most important presents of my life: a few dead crustaceans, and a small bag of dry mud. 

Well, that’s how my interest in inland waters, and wetlands, and ecology all started. I put the dry mud into a plastic lunchbox, added water, and waited. Within a day or two, larvae were buzzing around the “aquarium” and within a week, there were the shield shrimps and fairy shrimps and clam shrimps and ostracods and copepods. What biologist could fail to be intrigued by this amazing demonstration of adaptation in the form of crustaceans, quintessential aquatic organisms, surviving complete desiccation? (As an aside, these fairy, clam and shield shrimps are all primitive crustaceans belonging to the primitive crustacean class Branchiopoda. If you want to read more about their remarkable biology, download Vanishing Waters - see below.)

I didn’t morph from marine biologist to freshwater ecologist overnight, but I did become more interested in inland waters. I also realised that the term “fresh waters” isn’t always appropriate - many ponds and lakes throughout the world are brackish and some are even hypersaline.

At the time, I shared an office with another good friend, Jackie King. She had just started her PhD on Black Duck in the Eerste River, so was becoming very familiar with the freshwater invertebrates that live in rivers. (Don’t forget that my background was entirely on marine inverts.) We became the freshwater “experts” in the Zoology Department, which shows how very little expertise there was in the department at the time. (Horrendously, when the Zoology and Botany Departments merged some years ago, freshwater ecology once again disappeared and is still not studied at UCT, to the University’s eternal shame.) Jackie and I were soon confronted with the reality that many freshwater ecosystems in the vicinity of Cape Town were in very poor condition and were threatened by dams, and pollution, and alien invasive plants and animals - the same issues that confront them today. So if we wanted to study “pristine” rivers and wetlands, we would have to join hands with water managers and assist in the conservation and management of our favourite rivers and wetlands. We both took on this responsibility, if not with enthusiasm then certainly considering it to be our duty (although we didn’t think in such elevated terms at the time!) Jackie became a world expert in river management, ultimately winning the aquatic equivalent of a Nobel Prize - the Stockholm Prize for water management.

I became an academic in the Zoology Department at UCT, eventually paying the price of seniority and becoming Deputy Dean of Science for nearly a decade, followed by heaship  of the Department of Zoology for some years. On the freshwater front, Bryan Davies and I developed a semester-long third-year course in freshwater ecology, which was very popular and which generated quite a few freshwater professionals. I enjoyed lecturing to undergrads but my postgrads were a joy and an inspiration. The Zoology Department’s Freshwater Research Unit (FRU) became the premier institute for freshwater ecology in the country for more than 20 years. I hope that my PhD students who are now academics at other South African universities will succeed in reviving FRU in another manifestation. Freshwater research is still thriving in Cape Town, though, in the form of the Freshwater Reseach Centre, which was started by, and is run largely by, graduates from the old FRU.

On the research front, my students and I worked on rivers and wetlands in the Cape, trying to do some “proper science” despite a lack of funding for anything not considered to be of practical value. In the early days I was able to expand my interest in those little Namibian goggas, and spent quite a lot of time on field trips in the Namib, followed by lab work during term time. My love for those beasties has never left me, but logistics and finances meant that I was unable to concentrate on them. Instead, I have heen involved in water management: Department of Water Affairs, workshops, consulting, biodiversity conservation, water management in the City of Cape Town, East Africa, Australia …  

Download Vanishing Waters from https://www.wrc.org.za/?s=Vanishing+Waters 

Jenny Day 

 April 2025