Meet the Team: Rob!

•May 26, 2013 • Leave a Comment

As this project continues I am hoping that I will gradually be able to introduce the members of the team that are taking an interest in the broad. 

Many thanks to Robert (Rob) Riley who has submitted a short piece about his interests and degree programme within the school of Environmental Sciences at the University of East Anglia. 

Rob is and will be working with Dr Ros Boar in identifying and studying the algae that is present in the broad. 

“I am a first year Environmental Scientist with a keen interest in ecology and statistics. Next year I am studying Field Ecology and Aquatic Ecology, as well as maths, geophysics and the philosophy of nature. A project of this kind is ideal preparation for next year. Using a dichotomous key to identify diatoms in UEA broad gives me an insight into the richness of the microscopic world, whilst also increasing my proficiency with the use of microscopes. Working as part of a team of peers and lecturers will improve my research and time management skills. I also believe that the ethos and nature of this project makes the experience worthwhile. I like the fact that I am contributing to the data collection of the broad, which will provide an historical record of the environmental value of the broad. As a scientist, I like the fact that the trend behind the data is theoretically dynamic (i.e. as we assume there to be intraseasonal and interseasonal variation in algal populations), whilst also practically predictable (i.e. as we can test the assumption to assess the dynamics of the algal population). I am looking forward to continuing my support for this project.”

As summer begins and term ends in Norwich, it is a shame to say that my publications to the blog may be slightly less common, yet I hope to write a few feature articles throughout the summer! So stay tuned! 

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The Van Dorn Water Sampler

•May 5, 2013 • Leave a Comment

When we undertook our control sampling from the boat earlier in the week, a Vertical Van Dorn Water Sampler was used.

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This Van Dorn Water Sampler is intended for use in either shallow or deep water. While it may look quite complicated to use, it is actually quite simple…

– There is a chord fastened inside the releaser tube of the sampler.

– The top and bottom lids also have chords, and water passes through the tube when it is released into the broad.

– When the device has reached the desired depth in the water, a ‘messenger’ is attached to the lowering chord and released down toward the sampler tube.

– The messenger strikes the top of the release tube, depressing the pins and releasing the top and bottom lids.The lids close over the tube and trap the water within.

– The water sampler is then raised to the surface, where the water is transferred into sampling bottles ready to be taken to the lab!

(Adapted from Duncan and Associates Instructions)

An Exciting Day For Sampling! 30/04/2013

•April 30, 2013 • Leave a Comment

The sun was shining this morning as the sampling team for the day met outside the environmental field-store. Spirits were high among the team, as today, our sampling had an exciting edge to it…

In previous years before the pump system was installed into the UEA Broad a small boat was used to allow samples to be taken from the centre of the broad at 1m and 4m depths. Today, almost a year after the last boat trip onto the broad, samples were again collected using a ‘Van Dorn Water Sampler’ after rowing the dinghy out into the water.
The objective of using the boat today was as a control – to check that the samples obtained from the new pump system were the same as those taken by hand from the dinghy. 
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(Image One: Rob and Morgen are preparing the dinghy to be taken out onto the broad. Martin and Ros are preparing the Van Dorn Water Sampler)

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(Image Two: Martin and Rob are preparing to take their water samples from the broad) 
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(Image Three: Collecting samples from the broad) 

While Dr Martin Johnson (Martin) and Rob were collecting the first samples out on the broad, Morgen and I began collecting the first samples using the pump system. After flushing through the system, we collected our samples and took the temperature readings. At 1m depth the water temperature was 12°C, while at 4m depth the water samples were 11°C.

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(Image Four: Morgen preparing to take samples using the pump) 

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(Image Five: Morgen taking pump samples, while in the background samples are being taken from the boat by Martin and Rob) 

Martin and Rob found the first few samples to be quite slow work as it took some time getting used to using the Van Dorn Water Sampler again. There were also slight issues with the length markings on the rope used to deploy the sampler. Returning the first samples to the shore, Martin and Morgen then took to the water again to collect further samples at 4m depths.  

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(Image Six: Morgen and Marting preparing to collect further samples from different depths)

In tandem to water samples being collected Dr Rosalind Boar (Ros) was collecting samples of a slightly different nature using a Plankton Net to see the variety of plankton present in the broad.

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(Images seven and eight: Ros using the plankton net to collect samples)

After a very successful morning collecting samples, there are lots of ideas in the pipeline for developing awareness of this project among the community of The University of East Anglia, as well as linking our project to other independent projects that are also studying  shallow water bodies across the United Kingdom! 

Sampling Tuesday 24/04/2013

•April 24, 2013 • 1 Comment

At 11am Tuesday Morgen and myself met and went to complete the sampling of the UEA Broad. 

We were using the pump that was installed last year to take water two samples at 1m in depth and at 4m in depth. Morgen then took the temperatures of the water – we had readings of around 11 Degrees Celsius which is warmer than previous weeks samples that were 9 Degrees Celsius, meaning the UEA Broad is gradually warming up with the relative warm weather we’ve been experiencing in the last week! 

Morgen then took the samples back to the Laboratory to complete some analysis. 

I’ve included below a few photo’s of our sampling for your interest.

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(Image One: Morgen taking the temperature reading of the water) 

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(Image Two: The sample taken from 1m depth having its temperature measured) 

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(Image Three: The pump used to take water samples from the UEA Broad. The pump is connected to two pipes that are fitted in the Broad – either the 1m depth or 4m depth pipe) it is then flushed through first to get rid of any stagnant water that has settled in the pipe. Water is then collected and analysed) 

It is hoped that next Tuesday the team will be taking a small boat out onto the Broad which will be interesting and I’ll keep this site updated with what happens! 

Volunteer team working on UEA Broad

•April 13, 2013 • 1 Comment

A team of undergrad student volunteers will be working on the UEA broad project for the coming weeks. Led by a funded internship through UEA’s springboard programme (http://www.uea.ac.uk/internships) a team of students will be running the project, collating and managing the data, making additional measurements and trying to establish a sustainable model for the project to continue as a student-run volunteer project into the future.

For the past ~2 years regular (weekly) water samples have been taken from the lake by me and a couple of PhD student volunteers and analysed for a wide range of biogeochemical parameters including inorganic and organic nutrients, major ions, pH, conductivity, carbonate chemistry etc by the excellent analytical labs in the School of Environmental Sciences. This dataset is pretty unique in its broad range of chemical parameters measured at such high resolution, but there are some key measurements missing. For instance, we don’t know what species of phytoplankton or zooplankton are dominant in the lake or how they interact. We also don’t know what the chlorophyll concentration is, which would allow us to link chemical measurements to phytoplankton activity, or what the temperature profile of the lake is, which would be useful for understanding the vertical mixing in the lake, which links to vertical fluxes of measured chemical parameters. Also, whilst we have lots of chemical info on the dissolved phase, we can’t close the water column budgets of carbon, nitrogen etc as we don’t know what’s going on in the particulate phase.

For this reason, the volunteers will be making measurements of chlorophyll, particulate nitrogen and carbon and temperature in the lake as well as painstaking microscope work to identify and enumerate phytoplankton and zooplankton communities.  There will also be data compilation and analysis and outreach work as well as better documentation of the project here. Details of methods and the team responsible will be documented here later.

It’s really exciting to have a team of people working on the lake project – hopefully we can do some great science based on the data collected so far and the extra parameters we’ll be measuring over the next couple of months.

Peter Sheehan – A Report on Scientific Findings

•March 20, 2013 • Leave a Comment

The report below was kindly written for us by Peter Sheehan who studied the UEA Broad as part of his second year Environmental Analytical Chemistry module at UEA – A big thank-you for his contribution to the UEA Broad Time Series Project! 

“Introduction

This contribution to the UEA Broad Time Series Project (BTSP) follows my participation in an undergraduate coursework project in environmental chemistry at the School of Environmental Sciences. In this post, I summarise the main findings and compare them with previous results produced by the BTSP.

We measured the concentrations of four ions in the broad water: nitrate, ammonium, sulphate and chloride. Multiple measurements were made of each sample, sometimes generating an inconveniently wide spread of results! But statistical techniques were used to remove suspected anomalies and so produce numbers in which we can have confidence.

Water from the nearby river Yare was also sampled as part of the coursework project. Although these measurements are not of immediate relevance to the BTSP, these results shall be presented for the purpose of comparison, and will be discussed in places.

Methods

Broad water was sampled on the afternoon of the 23rd January, 2012 using the hand pump previously installed (see Sampling tubes installed for further information). The samples were filtered, before being stored frozen. Nitrate, sulphate and chloride concentrations were measured using an ion chromatograph; ammonium and phosphate concentrations were measured using an automated spectrophotometer. (Nitrate was measured using both instruments – so as to compare their precision accuracy – but, given that the latter cannot distinguish between nitrate and nitrite, the former is considered to be the more reliable.)

Results & Discussion

Table 1, below, contains the results of the measurements. The concentrations of the five ions in the river Yare are presented for comparison.

Peter Sheehan - Table 1

Peter Sheehan – Table 1

 

The standard deviations associated with the above measurements may be a little larger than one would expect from an analysis carried out by doctoral students or professional researchers, but they are not sufficiently large to render the data useless. Furthermore, that they are broadly consistent with measurements made at the end of 2011 – only a month or so before – indicates that they may be relied upon.

The following graphs present the results from previous years of the BTSP. Please note that these results are for the Broad only.

Peter Sheehan

Peter Sheehan

Ammonium_Graph

Peter Sheehan

Peter Sheehan

Peter Sheehan

Peter Sheehan

 

 

Previous years’ data show that the concentration of nitrate in the Broad follows a clear seasonal cycle. The nutrient is fairly abundant during the winter, but its concentration falls sharply in the spring; it is all but totally absent over the summer, but gradually reappears again in the autumn. This pattern is wholly expected: the ion is used as a nutrient by aquatic algae as they bloom in growing season (analogous to the space-visible plankton blooms in the extra-tropical oceans) and its annual disappearance acts as a break on their growth. But what drives the wintertime increase in the nitrate concentration? Firstly, Hughes et al. (2010) find that the nitrate concentration in the Broad increases after significant rainfall – an increase which cannot be explained by direct input from the rain itself – which, together with the observation that nitrate is strikingly more abundant in the Yare than the Broad (Table 1), suggests that groundwater flow between the two may be an important nutrient input. As an aside, the high nitrate concentration in the Yare has previously been attributed to the fact that the river drains an area of intensive agriculture (Edwards, 1973a).

Secondly, it is possible that oxidation of ammonium to nitrate be an important replenishment process. Although there is no clear seasonal or annual cycle, the peak in the ammonium concentration (Figure 2) that generally occurs after that of the nitrate concentration could be caused by the death and subsequent decay of the summertime algal bloom. Theory suggests that the two forms of nitrogen may be linked, although there is but little evidence in the BTSP data to corroborate this hypothesis. More data are needed.

The most recently measured concentrations of nitrate and ammonium in the Broad (Table 1) reveal further information about the nature of the seasonal cycles and interannual variability of each ion. The January 2012 value for nitrate, 36 ± 2 µmol l-1, is substantially less than the values measured around January 2007 and 2008: each was comfortably over 100 µmol l-1. Yet it is consistent with those values measured towards the end of 2011. This implies that interannual variability is considerable. Whereas nitrate concentrations peaked very early in 2007 and 2008, the evidence suggests that this year’s peak may have come some months later. Data from future years should enable us to determine whether this variation is typical for the UEA Broad. The January 2012 ammonium concentration appears to confirm the erratic nature of that ion’s cycle seen clearly in previous years’ data. From approximately 32 µmol l-1 in December 2011, the coursework results show that it fell to 9 ± 1 µmol l-1 in the intervening six weeks. Similarly abrupt changes occurred in September 2007, June 2008 and October 2009. Further investigation is needed to ascertain whether these changes are related to, for instance, biology in the Broad, other nutrients, or to weather conditions.

Unfortunately, given that we only have measurements of the sulphate and chloride concentrations for 2011 only, conclusions about the seasonal cycles and interannual variability of these two ions cannot be drawn. What’s more there are no surprises in the results from January 2012 (Table 1): only a small change from the previous month is observed (Figures 3 & 4), although the differences are greater than the relevant standard deviations in Table 1. What is interesting about the data in Figures 3 and 4 is the sudden, short-lived fall in each concentration observed in the first half of September. This feature seems unusual, and implies that there is a connection between the two ions. Indeed, the order-of-magnitude difference between the two concentrations notwithstanding, there seems to be a similarity in the shape of the two curves that again implies a connection. Yet, to the best of my knowledge, no chemical link – a common source or sink, for instance – strong enough to produce the observed similarity exists. This possibly merits further investigation; at the very least, future measurements should prove whether this apparent similarity is a long-lived feature, or whether it is a product of coincidence.

That chloride is the most concentrated of the ions discussed here is perhaps thanks, at least in part, to its being largely insignificant biologically. Furthermore, its abundance appears not to have changed a great deal in some decades. Concentrations reported by Edwards (1973b, see figure 3 of that publication) in the early 1970s indicate that only a modest but statistically significant (based on the above standard deviations) increase during the intervening years. It is unclear from the two whether this is part of a long-term trend or whether it is explained by natural variability. Rain is a likely a major source: bubbles bursting at the sea surface are a key input into the atmosphere. As for sulphate, Edwards (1973a) notes that both rainfall and sewage are significant inputs into the Yare. If we accept that groundwater flow between the Yare and the Broad is an important input to the latter of nitrate, then we must also consider that the same may be true of sulphate.

There are a number of unanswered questions already raised by the data BTSP. It is hoped that future data will help to provide some answers.”

 

References

Edwards, A.M.C., 1973a. Dissolved load and tentative solute budgets of some Norfolk catchments. Journal of Hydrology, 18, 201 – 217.

Edwards, A.M.C., 1973b. The variation of dissolved constituents with discharge in some Norfolk rivers. Journal of Hydrology, 18, 219 – 242.

Hughes, C., Kettle, A.J., Unazi, G.A., Weston, K., Jones, M.R. and Johnson, M.T., 2010. Seasonal variations in the concentrations of methyl and ethyl nitrate in a shallow freshwater lake. Limnology & Oceanography, 55, 305 – 314.

 

 

 

Sampling tubes installed!

•July 14, 2011 • Leave a Comment

Back at the beginning of June, following a successful bid for funding from the School of Environmental Sciences we  installed 120m of reinforced tubing mounted at the mooring in the deepest part of the lake to allow sampling from the banskide with a hand pump. Pumping enough water through to make sure we’re sampling fresh lake water is quite hard work, but it saves considerable time compared to our previous sampling method – pumping up an inflatable boat and rowing out to the middle of the lake, which was a 3 man job due to health and safety regulations! We’re now able to take regular weekly water samples, which will be analysed for nutrients, chlorophyll, particulate loading, alkalinity and other parameters.

More photos here: http://moblog.net/view/954262/installing-sampling-hoses-in-uea-broad