| 1. |
- Cael, B.B., et al.
(author)
-
How does lake primary production scale with lake size?
- 2023
-
In: Frontiers in Environmental Science. - : Frontiers Media S.A.. - 2296-665X. ; 11
-
Journal article (peer-reviewed)abstract
- Kleiber’s 3/4-scaling law for metabolism with mass is one of the most striking regularities in biological sciences. Kleiber’s law has been shown to apply not only to individual organisms but also to communities and even the whole-ecosystem properties such as the productivity of estuaries. Might Kleiber’s law also then apply to lake ecosystems? Here, we show that for a collection of whole-lake primary production measurements, production scales to the 3/4 power of lake volume, consistent with Kleiber’s law. However, this relationship is not explicable by analogy to theories developed for individual organisms. Instead, we argue that dimensional analysis offers a simple explanation. After accounting for latitudinal gradients in temperature and insolation, whole-lake primary production scales isometrically with lake area. Because Earth’s topography is self-affine, meaning there are global-scale differences between vertical and horizontal scaling of topography, lake volume scales super-linearly with lake surface area. 3/4 scaling for primary production by volume then results from these other two scaling relationships. The identified relationship between the primary production and temperature- and insolation-adjusted area may be useful for constraining lakes’ global annual productivity and photosynthetic efficiency. More generally, this suggests that there are multiple paths to realizing the 3/4 scaling of metabolism rather than a single unifying law, at least when comparing across levels of biological organization.
|
|
| 2. |
- Cael, B.B., et al.
(author)
-
Simple model of morphometric constraint on carbon burial in boreal lakes
- 2023
-
In: Frontiers in Environmental Science. - : Frontiers Media S.A.. - 2296-665X. ; 11
-
Journal article (peer-reviewed)abstract
- A geometric theory was developed to explain the empirical relationship between carbon burial and lake shape in boreal lakes. The key feature of this model is an attenuation length scale, analogous to models of marine organic carbon fluxes. This length scale is the ratio of how fast carbon is displaced vertically versus how fast it is respired and engenders a simple model with a single easily constrained free parameter. Lake depths are modeled based on fractal area–volume relationships that reflect the approximate scale invariance of Earth’s topography on idealized lake geometries. Carbon burial is estimated by applying the attenuation length scale to these depths. Using this model, we demonstrate the relationship between the dynamic ratio—a metric of lake morphometry calculated by dividing the square root of surface area by the mean depth—and carbon burial. We use scaling relationships to predict how dynamic ratio, and by extension carbon burial, varies across the lake size spectrum. Our model also provides a basis for generalizing empirical studies to the biome scale. By applying our model to a boreal lake census, we estimate boreal lake carbon burial to be 1.8 (Formula presented.) 0.5 g C/m2/yr or 1.1 (Formula presented.) 0.3 Tg C/yr among all boreal lakes.
|
|
| 3. |
- Cael, B. B., et al.
(author)
-
The size-distribution of Earth's lakes
- 2016
-
In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
-
Journal article (peer-reviewed)abstract
- Globally, there are millions of small lakes, but a small number of large lakes. Most key ecosystem patterns and processes scale with lake size, thus this asymmetry between area and abundance is a fundamental constraint on broad-scale patterns in lake ecology. Nonetheless, descriptions of lake size-distributions are scarce and empirical distributions are rarely evaluated relative to theoretical predictions. Here we develop expectations for Earth's lake area-distribution based on percolation theory and evaluate these expectations with data from a global lake census. Lake surface areas >= 8.5 km(2) are power-law distributed with a tail exponent (T = 1.97) and fractal dimension (d = 1.38), similar to theoretical expectations (T = 2.05; d = 4/3). Lakes <8.5 km(2) are not power-law distributed. An independently developed regional lake census exhibits a similar transition and consistency with theoretical predictions. Small lakes deviate from the power-law distribution because smaller lakes are more susceptible to dynamical change and topographic behavior at sub-kilometer scales is not self-similar. Our results provide a robust characterization and theoretical explanation for the lake size-abundance relationship, and form a fundamental basis for understanding and predicting patterns in lake ecology at broad scales.
|
|
| 4. |
- Cael, B.B., et al.
(author)
-
The size-distribution of earth's lakes and ponds : limits to power-law behavior
- 2022
-
In: Frontiers in Environmental Science. - : Frontiers Media S.A.. - 2296-665X. ; 10
-
Journal article (peer-reviewed)abstract
- Global-scale characterizations of Earth's lakes and ponds assume their surface areas are power-law distributed across the full size range. However, empirical power-laws only hold across finite ranges of scales. In this paper, we synthesize evidence for upper and lower limits to power-law behavior in lake and pond size-distributions. We find support for the power-law assumption in general. We also find strong evidence for a lower limit to this power-law behavior, although the specific value for this limit is highly variable (0.001–1 km2), corresponding to orders of magnitude differences of the total number of lakes and ponds. The exact mechanisms that break the power-law at this limit are unknown. The power-law extends to the size of Earth's largest lake. There is inconsistent evidence for an upper limit at regional-scales. Explaining variations in these limits stands to improve the accuracy of global lake characterizations and shed light on the specific mechanism responsible for forming and breaking lake power-law distributions.
|
|
| 5. |
- Cael, B. B., et al.
(author)
-
The volume and mean depth of Earth's lakes
- 2017
-
In: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 44:1, s. 209-218
-
Journal article (peer-reviewed)abstract
- Global lake volume estimates are scarce, highly variable, and poorly documented. We developed a rigorous method for estimating global lake depth and volume based on the Hurst coefficient of Earth's surface, which provides a mechanistic connection between lake area and volume. Volume-area scaling based on the Hurst coefficient is accurate and consistent when applied to lake data sets spanning diverse regions. We applied these relationships to a global lake area census to estimate global lake volume and depth. The volume of Earth's lakes is 199,000km(3) (95% confidence interval 196,000-202,000km(3)). This volume is in the range of historical estimates (166,000-280,000km(3)), but the overall mean depth of 41.8m (95% CI 41.2-42.4m) is significantly lower than previous estimates (62-151m). These results highlight and constrain the relative scarcity of lake waters in the hydrosphere and have implications for the role of lakes in global biogeochemical cycles.
|
|
| 6. |
- Carlson, Michael. C. G., et al.
(author)
-
Viruses affect picocyanobacterial abundance and biogeography in the North Pacific Ocean
- 2022
-
In: Nature Microbiology. - : Springer Science and Business Media LLC. - 2058-5276. ; 7:4, s. 570-580
-
Journal article (peer-reviewed)abstract
- The photosynthetic picocyanobacteria Prochlorococcus and Synechococcus are models for dissecting how ecological niches are defined by environmental conditions, but how interactions with bacteriophages affect picocyanobacterial biogeography in open ocean biomes has rarely been assessed. We applied single-virus and single-cell infection approaches to quantify cyanophage abundance and infected picocyanobacteria in 87 surface water samples from five transects that traversed approximately 2,200 km in the North Pacific Ocean on three cruises, with a duration of 2–4 weeks, between 2015 and 2017. We detected a 550-km-wide hotspot of cyanophages and virus-infected picocyanobacteria in the transition zone between the North Pacific Subtropical and Subpolar gyres that was present in each transect. Notably, the hotspot occurred at a consistent temperature and displayed distinct cyanophage-lineage composition on all transects. On two of these transects, the levels of infection in the hotspot were estimated to be sufficient to substantially limit the geographical range of Prochlorococcus. Coincident with the detection of high levels of virally infected picocyanobacteria, we measured an increase of 10–100-fold in the Synechococcus populations in samples that are usually dominated by Prochlorococcus. We developed a multiple regression model of cyanophages, temperature and chlorophyll concentrations that inferred that the hotspot extended across the North Pacific Ocean, creating a biological boundary between gyres, with the potential to release organic matter comparable to that of the sevenfold-larger North Pacific Subtropical Gyre. Our results highlight the probable impact of viruses on large-scale phytoplankton biogeography and biogeochemistry in distinct regions of the oceans.
|
|
| 7. |
- Seekell, David A., et al.
(author)
-
Problems With the Shoreline Development Index—A Widely Used Metric of Lake Shape
- 2022
-
In: Geophysical Research Letters. - : American Geophysical Union (AGU). - 0094-8276 .- 1944-8007. ; 49:10
-
Journal article (peer-reviewed)abstract
- The shoreline development index—The ratio of a lake’s shore length to the circumference of a circle with the lake’s area—Is a core metric of lake morphometry used in Earth and planetary sciences. In this paper, we demonstrate that the shoreline development index is scale-dependent and cannot be used to compare lakes with different areas. We show that large lakes will have higher shoreline development index measurements than smaller lakes of the same characteristic shape, even when mapped at the same scale. Specifically, the shoreline development index increases by about 14% for each doubling of lake area. These results call into question previously reported patterns of lake shape. We provide several suggestions to improve the application of this index, including a bias-corrected formulation for comparing lakes with different surface areas.
|
|
