In 1969, Derek York published a highly general solution to the common problem of how to fit a straight line to points measured with error in both x and y. Unfortunately York's solution is almost unknown outside the geophysical literature, and new studies wrestle with the problem each year. We introduce York's solution and demonstrate it using an example from biogeochemistry: the isotopic mixing line. By Monte Carlo simulation, we show that York’s solution is superior to all popular fit methods.

This paper presents results from a year-long study of a kelp forest offshore of Pacific Grove, California. We use tools and techniques from chemistry to study the kelp forest. We find very large chemical variability in the kelp forest, primarily between the surface of the water and the bottom of the forest. There are many reasons for this variability; we conclude that both regional upwelling and kelp growth are responsible for contributing to this variability.

Ozone is a toxic air pollutant that can damage plant leaves and impact their carbon uptake from the atmosphere. We extend a terrestrial biosphere model to account for ozone damage of plants and investigate the impact on the terrestrial carbon cycle. Our approach accounts for ozone transport from the free troposphere to leaf level. We find that this substantially affects simulated ozone uptake into the plants. Simulations indicate that ozone damages plants less than expected from previous studies

This study documents how much control growth rate has on the chemical composition of fossil shell material. Using a series of chemical analyses of the fossil hard part of a belemnite, an extinct marine predator, a clear connection between the rate of calcite formation and its magnesium and strontium contents was found. These findings provide further insight into biomineralization processes and help better understand chemical signatures of fossils as proxies for palaeoenvironmental conditions.

Carbon cycling in Himalayan mountain forest ecosystems is not well studied. We studied soil respiration and its autotrophic and heterotrophic components as well as the effects of environmental drivers in mixed and broadleaf forest ecosystems in the Bhutan Himalayas for the first time. Soil respiration rates were similar in the two forest ecosystems. A simple temperature-driven model was able to explain more than 90 % of the temporal variation in soil respiration.

Separating tree and grass productivity dynamics in savanna ecosystems is vital for understanding how they function over time. We showed how tree-grass phenology information can improve model estimates of gross primary productivity in an Australian tropical savanna. Our findings will contribute towards improved modelling of productivity in savannas, which will assist with their management into the future.

Plant nitrogen (N) isotope composition is an indicator of N cycling. How N isotopes are distributed within plants is not well understood. We found intra-plant variations in N isotopes were related to organ N and phosphorous (P) contents and predicted by the N–P interaction. We hypothesized that plant N volatilization, resorption and remobilization of N and P from senescing leaves, and mixing of the re-translocated foliar N and P, are responsible for the observed intra-plant N isotope variations.

Climate change is strongly regulated by land carbon cycle. However, we lack the ability to predict future land carbon sequestration. Here, we develop a novel framework for understanding what determines the direction and rate of future change in land carbon storage. The framework offers a suite of new approaches to revolutionize land carbon model evaluation and improvement.

Regional estimated uncertainties originate from methodological failures, errors, and supporting data insufficiency. A case study showed that the fallacy of the CH4MOD contributed 56.6 % to the uncertainty of a national inventory, with the remaining 43.4 % attributed to the scarcity of model inputs. We also revealed a dilemma between model performance and data availability: a model with better performance may reduce uncertainty from model fallacy but increases the uncertainty from data scarcity.

The biological carbon pump (BCP) plays a key role in regulating atmospheric CO₂. Controls on the efficiency at which this occurs are poorly known. Here we combine in situ observations with an ecosystem model to show that zooplankton have an important role in regulating the efficiency of the BCP. Predicted future changes in ocean conditions, such as expansion of oxygen minimum zones, may decrease the role of zooplankton in the BCP globally, increasing its efficiency and altering atmospheric CO₂.

In order to quantify greenhouse gas fluxes from typical eastern African smallholder farms, we measured flux rates every week for 1 year at 59 farms in western Kenya. These upland soils tend to be small sinks for CH₄ and small sources of N₂O. The management intensity of the farm plots had no effect on emissions, likely because the variability was low. Plots with trees had higher CH₄ uptake than other plots. This suggests that emissions from small, low-input farms in this region are quite low.

To investigate seasonal distribution of short-tailed shearwaters we conducted vessel-based seabird surveys and net samplings of krill, i.e., their main prey, during summer and fall in the Bering Sea and Chukchi Sea. Short-tailed shearwaters in the Bering Sea during summer moved to feed in the Chukchi Sea during fall, which might be associated with the seasonal increase in krill size in the Chukchi Sea.

This research characterised the biogeochemical constraints on the origin of methane in an alluvial aquifer, concluding that the most likely source was the upward migration from a directly underlying coal seam. This research was undertaken due to concerns about the effect of coal seam gas production on groundwater quality in the study area. The implications include the fact that no methane is being produced in the aquifer (in situ) and that there is local natural connectivity in the study area.

We measured the sulfur gas dimethylsulfide (DMS) in marine air at a coral cay on the Great Barrier Reef. DMS is well known to be released from the world's oceans, but environmental evidence of coral reefs releasing DMS has not been clearly demonstrated. We showed the coral reef can sometimes release DMS to the air, which was seen as spikes above the DMS released from the ocean. The DMS from the reef supplements the DMS from the ocean to assist formation of clouds that influence local climate.

To evaluate different mechanisms underlying nitrogen (N) pulses that occur following fires in pyrogenic US savannas, we coupled field measures of soil N cycling with soil N isotopic signatures. We found that neither ash deposition nor changes to microbial activity could account for observed N pulse. We hypothesize that changes to plant uptake may contribute to the post-fire N pulses. We encourage future work to explore the role of plant activity on temporal nutrient availability dynamics.