The Negative Effects of Ocean Acidification on the Physiology of Marine Animals and Fauna

The negative effects of ocean acidification on the physiology of marine animals and fauna

Introduction

With the increasing CO2 levels of the ocean, this factor causes a change in the pH levels of the ocean. Research is ongoing to investigate the effects of the acidification of the ocean and its negative effects on the physiology of marine animal and fauna. Taylor et al. (2015) investigated the effects of ocean acidification on the exoskeleton and the biophotonic properties of Lymata californica in the short-term, while Sarmento et al. (2015) investigated the effects of acidification on a phytal meiofauna community. Fernadez et al (2015) focused on the physiology growth and processes of Macroytis pyrifera under the exposure of increased pH levels of ocean water. Wizemann et al. (2015) also investigated the effects of ocean acidification on kelp physiology but focusing on the skeletal microskeleton of the kelp species Halimeda oputia.MacLeod and Poulin (2013) summarised how coral reefs are formed and eroded through bioerosion and CaCO3 dissolution while discussing how ocean acidification can influence these natural processes. This annotated bibliography will discuss the negative effects of ocean acidification on the physiology of marine animals and fauna communities.

Keywords: CO2-induced, increased pH levels, coral reefs, consequences

Taylor, JRA, Gilleard, JM, Allen, MC, Deheyn, DD (2015) Effects of CO2-induced pH reduction on exoskeleton structure and biophotonic properties of shrimp Lysmata californica. Sci Rep 5:10608 doi: 10.1038/srep10608

Ocean acidification is known to have negative effects upon marine animals and plants. This article aims to test out the consequences of CO2 induced acidification of saltwater on exoskeleton growth, structure and mineralization and animal crytic colouration by altering the pH (7.53+/- 0.06) and the ambient (7.99+/-0.04) of saltwater and exposing the shrimp Lysmata califronica within it for 21 days. Results show that over short-term exposure to the conditions of the saltwater, the L. caifronica showed that the growth was not impacted, but the mineralization of the exoskeleton has changed with an increase of calcium in the exoskeleton. The course of the study was relatively short, however it showed the impacts caused by CO2-induced pH reduction of saltwater. If the study was carried longer more potential impacts of ocean acidification onto L. californica on crypsis, physical defence and predator avoidance could have been discovered.

The primary article provides good detail in the short exposure of increase pH levels to marine animals and gives a good direction for further studies in the behavioural consequences of these changes. 3.5/5

Fernandez, PA, Roleda, MY, Hurd, CL (2015) Effects of ocean acidification on the photosynthetic performance, carbonic anhydrase activity and growth of the giant help Macrocytis pyrifera. Photosynth Res 124: 293-304

The effects of ocean acidification can cause changes that can be beneficial or ill towards the physiology of marine plants. The aim of this study is geared towards the observation of the kelp Macrocystis pyrifera and the effects of CO2-induced acidification on the kelp’s growth, photosynthesis rate, and external and internal carbonic anhydrase (CA) activity. The study was conducted by having 2 separate treatments, the 1st group of M. pyrifera was placed into a tank with pCO2/pH treatments of 400u; pH 8.00 and the 2nd group with 1200uatm; pH7.59 treatment over a 7 day period. Results showed that no changes in growth, photosynthesis rate nor external and internal CA activity, however the combination of factors need to be further investigated for influences affecting M. pyrifera physiology.

The comparison with past studies gives a good indication that it the background was well researched and it gives a good direction for future studies. 3.5/5

Sarmento, V.C, Souza, T.P, Esteves, A.M, Santos, P.J.P (2015) Effects of seawater acidification on coral reef meiofauna community. Coral reefs 34: 955-966

Coral reefs are the most threatened under the changes of pH of the ocean. This study aims to observe the changes within a phytal meiofauna community under the effects of ocean acidification. The study was conducted by collecting the fauna through ASU and placing them into 4 treatment groups excluding the control at pH 8.1, 7.8, 7.5 and 7.2 for a total of 30 days, with the pH and temperature being controlled by a computerised system. Samples of the different treatments were collected at 15 and 30 days for comparison. There were divergent results shown from the fauna collected, some fauna showed tolerance to ocean acidification while other faunas did not.

The primary article gave a good insight to the consequences from ocean acidification. As well as highlighting the fragility of the coral ecosystem and the potential dangers that acidification brings to the ecosystem. 3/5

Wizemann, A, Meye, F.W, Hofmann, L.C, Wild, C, Westphal, H (2015) Ocean acidification alters the calcareous microstructure of the green macro-alga Halimeda opuntia. Coral reefs 34: 941-954

Increasing acidification of the ocean waters is potential threat to marine calcifiers. The aim of the study was to identify the changes of the species Halimeda opuntia in regards to the internal skeleton CaCO3 microstructure when affected by ocean acidification. The algae H. oputina samples were separated into different CO2 concentrations and allowed to grow in the mesocosms, afterwards samples were taken and an electron microscopy was used to view the skeletal microskeleton. It was found that while growth of new needles was uninhibited, the actual sizes of the needles were observed to be longer than the needles in the control treatment. However the needles were substantially thinner due to the loss of micro-anhedral carbonate from the observations of the central utricles. This reduces the efficiency of H. oputina to intake CO2 and its environmental success.

The method to replicate the study was in great detail as well as the consequences of acidification on the kelp H. oputina. 3/5

Andersson, A.J, Gledhill, Dwight (2013) Ocean Acidification and Coral reefs: Effects on Breakdown Dissolution, and Net Ecosystem Calcification. Annual Review of Marine Science 5: 321-348

In this review Andersson and Gledhill (2013) investigates bioerosion, CaCO3 dissolution, and net ecosystem calcification (NEC), and the alterations of these processes that will occur under ocean acidification